Parasagittal dura (PSD) is located on both sides of the superior sagittal sinus and harbours arachnoid granulations and lymphatic vessels. Efflux of cerebrospinal fluid (CSF) to human PSD has recently been shown in vivo. Here we obtain PSD volumes from magnetic resonance images in 76 patients under evaluation for CSF disorders and correlate them to age, sex, intracranial volumes, disease category, sleep quality, and intracranial pressure. In two subgroups, we also analyze tracer dynamics and time to peak tracer level in PSD and blood. PSD volume is not explained by any single assessed variable, but tracer level in PSD is strongly associated with tracer in CSF and brain. Furthermore, peak tracer in PSD occurs far later than peak tracer in blood, implying that PSD is no major efflux route for CSF. These observations may indicate that PSD is more relevant as a neuroimmune interface than as a CSF efflux route. Human MRI data shows that parasagittal dura volume may not play a major role in cerebrospinal fluid clearance but could instead serve as a neuro-immune interface. Traditionally, the proposed efflux routes include passage directly to the venous sinuses via arachnoid granulations, along cranial and spinal nerve routes, and across the vessel walls in brain capillaries2.The human brain is immersed in cerebrospinal fluid (CSF) and surrounded by the meninges. How the efflux of CSF takes place has been studied over centuries without any firm conclusion4. Impairment of these dural lymphatic vessels decreases the clearance of macromolecules and tracers from the brain: In transgenic mice lacking a functional lymphatic system, injected tau clearance was delayed5. In wild-type mice where the dural lymphatic vessels were ablated, clearance of injected tracers with different sizes was delayed and, in the same study, ablation of dural lymphatic vessels in transgenic mice models of Alzheimer’s disease (AD) led to increased amyloid-beta plaque load in the brain and amyloid-beta depositions in the meninges6. These findings highlight the importance of dural lymphatic vessels for clearance from the brain in animal studies and carry implications for several neurodegenerative diseases, including AD.In 2015, true lymphatic vessels with CSF drainage function were discovered in the dura mater of mice7. In previous anatomical studies, PSD also harbours arachnoid granulations and venous channels that were hypothesised to take part in CSF drainage8. Moreover, PSD contains fluid vacuoles that may serve as reservoirs for CSF drainage9.After intrathecal administration of a CSF tracer in humans, the tracer passed directly from CSF to dura mater adjacent to the superior sagittal sinus, a location where density of lymph vessels is high, the so-called parasagittal dura (PSD)Based on these observations, constituents of PSD may represent a determining step for clearance capacity of brain solutes via CSF to blood. We, therefore, hypothesise there is an association between the volume of PSD and the clearance function of PSD and that the PSD clearance function can be assessed by time-dependent enrichment of tracer from CSF. Primarily, we asked how various clinical- and imaging variables correlate with PSD volume. Secondarily, we questioned the association between PSD volume and enrichment and clearance of a CSF tracer from various locations, including cerebral cortex, white matter, subarachnoid space, CSF, and PSD. Finally, we compared CSF tracer efflux to PSD with tracer concentrations in blood.The study enrolled 82 patients who underwent intrathecal contrast-enhanced magnetic resonance imaging (MRI) from November 2016 to December 2019. Of these, six patients had to be excluded after imaging due to difficulties to segment PSD for various reasons: three patients with diffuse dural thickening, two with the poor image quality from motion artefacts, and one with cerebral venous sinus thrombosis. The remaining 76 patients were finally included in the material and analysed.At the Department of neurosurgery, the 76 patients were divided into different categories based on their clinical diagnosis at the time of evaluation for tentative CSF disorders: arachnoid cysts (AC); pineal cysts (PC), idiopathic intracranial hypertension (IIH), spontaneous intracranial hypotension (SIH), hydrocephalus conditions (HC) and dementia (D) Table . DemograExamples of PSD volume segmentations based on fluid-attenuated inversion recovery-MRI (FLAIR-MRI) and 3D images of two different patients are presented in Fig. R = 0.359, P = 0.001), but was not correlated with volume measures of CSF , cerebral cortex grey matter  or subcortical white matter , respectively. Individual data points shown in Supplementary Table The PSD volume correlated with the total intracranial volume . Moreover, PSD volume was significantly larger in male than female . We found no association between PSD volume and body mass index.Considering the entire material, there was a positive correlation between age and PSD volume .The diagnostic categories differed somewhat regarding PSD volume, with an overall significant difference between groups (n = 68), there was no association between PSD volume and subjective sleep quality . Moreover, poor sleepers (PSQI > 5) and good sleepers (PSQI ≤ 5) did not differ concerning PSD volume. It should be noted, however, that IIH patients presented with poorer sleep quality than REF patients, and that the PSD volume was reduced in IIH versus REF patients.To explore whether PSD volume is associated with sleep, we examined the correlation between PSD volume and subjective sleep quality . Considering all patients with PSQI scores (n = 38), PSD volume correlated negatively with MWA, both regarding the average of MWA  and the percentage of recording time with MWA above established the threshold value (>6 mmHg) . The static ICP (mean ICP), on the other hand, was not associated with the PSD volume .There was a significant negative correlation between PSD volume and the pulsatile intracranial pressure (ICP) as given by the mean ICP wave amplitude (MWA). For the subjects with ICP recordings  turned out to have any significant effect on PSD volume. Therefore, none of the presently addressed variables had a strong effect on PSD volume.R = 0.79, P < 0.001), 6 hours , 24 hours  and 48 hours .There was a strong and highly significant association between tracer enrichment in PSD and tracer enrichment in nearby subarachnoid CSF space at 3 hours .Notably, the time to peak tracer enrichment in PSD was not correlated with time to maximum plasma concentration of tracer Fig. . FurtherR = −0.17, P = 0.30), 6 hours  or 24 hours , but there was a positive correlation between PSD volume and tracer enrichment in PSD at 48 hours .On the other hand, the PSD volume was not strongly associated with the degree of tracer enrichment in PSD. Hence, there was no significant correlation between PSD volume and tracer enrichment after 3 hours (P = 0.038).We further noted some differences between patient categories. For example, after 48 hours, tracer enrichment in PSD was markedly lower in IIH patients than REF subjects , while this was not seen for static ICP . For individual data points, see Supplementary Table Furthermore, there was a significant negative correlation between pulsatile ICP (average MWA) and tracer enrichment in PSD at 24 hours  Table . AccordiTracer enrichment in PSD was significantly correlated with tracer enrichment in the cerebral cortex, subcortical white matter, and the CSF tracer enrichment at vertex Table .Table 3CR = −0.31, P = 0.06), 6 hours , 24 hours  or 48 hours . Second, there was no correlation between PSD volume and tracer enrichment in cerebral cortex at 3 hours , 6 hours , 24 hours  or 48 hours . Third, PSD volume was neither correlated with tracer enrichment in subcortical white matter at 3 hours , 6 hours , 24 hours  or 48 hours . Individual data points of tracer enrichment in the various locations are shown in Supplementary Table On the other hand, PSD volume was not correlated with tracer enrichment in the various compartments: First, PSD volume did not correlate with tracer enrichment in CSF at 3 hours  PSD volume shows large inter-individual variations, (2) PSD volume correlates positively with intracranial volume and negatively with intracranial pulse pressure (MWA); however, no single factor explained PSD volume, and neither was it associated with CSF tracer enrichment in brain, CSF or in PSD itself. (3) After intrathecal administration of tracer, time of peak enrichment in CSF around the upper brain convexities and in PSD occurred far later than the occurrence of peak concentration in blood. The dissociation in time between peak enhancement of CSF tracer in PSD and blood, clearly suggests that most CSF tracer was cleared from the subarachnoid space before it reached PSD and that CSF resorption via PSD and dural lymphatic vessels at the vertex are quantitatively less important compared to other efflux routes. This adds to earlier assumptions from cisternography that the subarachnoid space above the cerebral convexities is not a major bulk efflux route14. In inflammatory and degenerative diseases, T-cells might even enter CSF from PSD15. How the antigens cross the arachnoid, a tissue by some thought impermeable to macromolecules2 is not fully understood, but recently two different anatomical studies describe passage of molecules from the subarachnoid space to PSD: The first via endothelial lined channels;16 The other via arachnoid granulations17. Ligation of dural lymphatic vessels in rodents did not reduce passage from CSF to dura, suggesting dural stroma is an intermediate step for CSF efflux before entry into lymph vessels13. This experimental finding correlates to our in vivo observation of tracer diffusely spread throughout PSD, far more extensive than only confined to lymph vessels, which probably would be difficult to detect with MRI. In animals, the cribriform plate is a major efflux route for CSF2, but its importance as an immunological interface has been questioned in favour of dural lymphatics14. These observations imply that major CSF efflux routes and CSF immune surveillance could be anatomically separated in both animals and humans.Even if PSD does not seem to constitute a major efflux route, it could still have important functions not reflected by its size or tracer dynamics. It has recently been demonstrated in experimental animal studies that PSD stroma may serve as a major hub for crosstalk between the CNS and peripheral immune system. Here, CNS-derived antigens are presented by dendritic cells to blood-borne T-cells, indicating that the CNS has pushed its immunological boundaries towards its borders22, all of that are constituents that may contribute to the high signal in PSD on FLAIR images. The appearance of intradural channels differs somewhat between microscopic studies, but they are not clearly lymphatic21. Intradural channels have been suggested to function as an intermediate step between CSF and the dural lymph vessels9. The CSF tracer observed to diffusely enhance PSD could originate from entry into several of its constituents. One should therefore be cautious to interpret any high signal in PSD on FLAIR images to represent only lymph, as recently done23. Our inability to directly depict tubular lymph-like structures within the PSD, even at long-term imaging after injection of CSF tracer, indeed questions whether tubular structures visualised in dura mater shortly after intravenous administration of MRI contrast agent, truly represent lymphatic vessels as previously described24, but rather contrast within any of the PSD structures including circulating contrast agent within dural veins.It should be emphasised that PSD as shown by MRI-FLAIR harbours much more than lymphatic vessels and is therefore not synonymous with lymph. A consistent finding in PSD is intradural channels, vacuoles and veins embedded in a stromaThere was a strong correlation between tracer enrichment in the various locations: PSD, CSF, cerebral cortex and subcortical white matter. Being a small molecule, the results indicate that gadobutrol propagation between these compartments is by large governed by diffusion along concentration gradients. Furthermore, the findings emphasize the close connection between the interstitial space in the brain, CSF, and PSD and the possibility for fluid exchange along this route with the CSF compartment acting as a bridging link between the brain and the dura.26. Patients with AD had less visible intradural channels compared to younger non-AD individuals in a limited post-mortem study21. This could be related to age differences and not AD, but still, an interesting finding as PSD volume increases with age and the channels in PSD decrease with age or AD. The PSD volume was not assessed in that study and the intradural channels could have been collapsed or affected by fibrosis21. As stated before, FLAIR images will not be able to differentiate the contents of PSD and the increase in volume with age could be attributed to increased connective tissue, lymphatic vasculature, or intradural channels. The small number of patients with dementia in our study (n = 2) makes correlations to the various variables, including PSD volume, of limited value for this patient category.Both increasing age and male sex correlated positively with PSD volume, consistent with earlier findings27 and decrease after sleep deprivation28. Also, poor sleep quality has been associated with tracer enrichment in regional areas of the brain29. A previous animal study has shown increased CSF clearance in wake rodents compared to anesthetized30, but an in vivo human study of CSF tracer clearance to PSD showed no impact from sleep deprivation31. In this study, sleep quality and PSD volume did not correlate. Considering no association between PSD volume and CSF clearance was observed, no correlation between sleep quality and PSD volume is expected.The differences in clearance from the brain and CSF in sleep and wake state have been assessed in both animal and human studies before. In short, clearance of macromolecules from the brain has been shown to increase during sleep32. The mechanisms behind SIH and IIH are not known and the differences in PSD volume and tracer dynamics are more probably a result of ICP rather than the causes of the diseases. Reduced compliance, as indicated by increased pulsatile ICP (MWA)34, could lead to altered flow dynamics, both within the brain32, and in the subarachnoid space35 with less tracer reaching the convexity of the brain. In addition, the increased pulsatile ICP could also lead to anatomical changes, in this case, decreased volume of PSD.The differences in PSD volume between patient categories with higher volume in patients with SIH compared to patients with IIH and the negative correlation between PSD volume and pulsatile ICP measurements are noteworthy. There is also a negative correlation between pulsatile ICP and tracer enrichment in PSD and nearby CSF. In a previous study, our group observed increased enrichment and delayed clearance of a CSF tracer from the brain in patients with IIH and increased pulsatile ICP (MWA)37. This could be the result of bulk flow in the cranial direction and main efflux at the vertex as originally described, but our data with peak concentrations in blood before maximum tracer signal in PSD, clearly suggest the tracer has left the subarachnoid space via other routes, and the tracer observed at the vertex in Di Chiros study was a result of limited movement of the parasagittal CSF, as previously discussed by Greitz10. Injection to the subarachnoid space intracranially would probably result in a different temporal correlation between maximum signal in PSD and maximum blood concentration, but injection to the intracranial subarachnoid space was not feasible in our study setting.The CSF tracer was injected at lumbar level, the most used injection site for human in vivo tracer studies throughout history, probably due to a good safety profile. Di Chiro injected radio-iodinated albumin intrathecally at the lumbar level in humans and observed tracer accumulating at the vertex of the skull after 24 hoursWe utilized correlation analysis in this cohort of tentative CSF disorders for a possible association between PSD volume, disease category, and tracer enrichment. The associations observed do not prove causality, as in the case of differences between the SIH and IIH cohorts. The examined group were heterogeneous with poorly understood clinical conditions of CSF disorders with few patients in each disease category and healthy individuals were not included.In conclusion, the present results suggest that PSD has no major role in CSF clearance. Its volume could by large neither be explained by other single parameters we investigated, including anatomical- and ICP metrics. Whether the neuroimmune function of PSD is size dependent should be a matter of investigation in further studies.The study was approved by the Institutional Review Board (2015/1868), the Regional Ethics Committee (2015/96), and the National Medicines Agency (15/04932-7). The patients were included after written and oral informed consent and registered in Oslo University Hospital Research Registry (ePhorte 2015/1868).Patients referred to the Department of Neurosurgery, Oslo University Hospital—Rikshospitalet, for CSF circulation disorders were included. Intrathecal contrast-enhanced MRI was done on clinical indication in all subjects. Inclusion criteria were available MRI acquisitions with 3D T1-gradient echo (T1-GRE), 3D T1 Black blood (BB), and 3D T2-Fluid Attenuated Inversion Recovery (FLAIR) sequences. Exclusion criteria were: age <18 years or >80 years; history of hypersensitivity reactions to contrast media agents; severe allergy reactions in general; evidence of renal dysfunction, pregnancy, and breastfeeding. The study design was prospective and observational.3D T1-gradient echo (T1-GRE): sagittal scanning plane; repetition time (TR) = shortest ; echo time (TE) = shortest ; echo train length (ETL) = 232; flip angle = 8°; 1 average; 1 mm isotropic voxels reconstructed to a 512 × 512 × 368 3D array. Acquisition time: 6 min and 29 s.3D T1 Black blood (T1-BB): sagittal scanning plane; TR = 700 ms; TE = 35 ms; ETL = 55; flip angle = 80°; 2 averages; 1 mm isotropic voxels reconstructed to a 432 × 432 × 426 3D array. Acquisition time: 4 min and 54 s.3D T2-Fluid Attenuated Inversion Recovery (FLAIR): sagittal scanning plane; TR = 4800 ms; TE = 311 ms; inversion time = 1650 ms; ETL = 167; flip angle = 90°; 2 averages; 1 mm isotropic voxels reconstructed to a 512 × 512 × 365 3D array. Acquisition time: 5 min and 41 s.We used a 3 Tesla Philips Ingenia MRI scanner with a 32-channel head coil for the following sequences:T1-GRE, T1-BB, and FLAIR scans were obtained pre-contrast. T1-GRE and T1-BB were repeated at approximately 0.5, 3, 6, 24, and 48 h after intrathecal injection of 0.5 ml gadobutrol (1 mmol/ml) . Correct needle position prior to gadobutrol injection was either verified by free CSF flow from the needle or injection of radiopaque iodixanol . For the first 6 hours after injection the patients were kept in supine position with a pillow under their heads, after that, they could move without any restrictions.T1-GRE and FLAIR sequences were obtained for all participants. T1-BB images were obtained for 46/76 patients.All image processing and analysis were blinded to the patients’ age, gender, and clinical data.http://surfer.nmr.mgh.harvard.edu/)38. To adjust for intensity differences in the images, the signal intensities between scans were normalized to the signal in the retrobulbar fat at the same time point. This resulted in images of tracer enrichment in the brain over time for each patient. The process of alignment and normalization is more extensively explained in a previous work39. The signal intensities for the total cortical grey matter and the white matter are based on these processing steps. The volumes of cortical gray matter and cerebral white matter were obtained from T1-GRE. In five patients the FreeSurfer registration, segmentation, or parcellation failed. No data from dynamic contrast images of the brain were obtained for these patients and all intracranial volumes were instead calculated with SPM12.For each subject, the T1-GRE volumes for all time points were registered to the same space using FreeSurfer version 6.0 . For each subject and time point, regions of interests (ROI) were placed in PSD and the most adjacent CSF compartment, i.e., in the upper parasagittal subarachnoid space. The signal intensities were normalised to a reference ROI in the vitreous body of the ocular bulb. The data from the ROI measurements in PSD have been published previously in 18/46 patientshttps://www.slicer.org)41 to exclude fluid-attenuated CSF and most of the flowing blood. PSD was then manually segmented in three planes using ITK-SNAP version 3.8.0 (http://www.itksnap.org)42. Most large veins were excluded in the previous threshold step, but some high-signal vessels had to be removed manually. An in-house artificial intelligence (AI)-software based on a two-dimensional U-Net43 convolutional network with close resemblance to a tested model, BodySegAI44, was trained from this data and used to segment PSD in another seven subjects. U-Net was chosen for good performance from a limited training set. The resulting seven AI segmentations were manually corrected by the first author (EM) and used to further train the AI model. The remaining sixty-two subjects were segmented using this latest AI model and manually reviewed and corrected if needed. The AI model was used for more efficient segmentation; Accuracy of the AI model was not estimated.We used FLAIR images to segment PSD. PSD was defined as the space with intermediate to high signal next to superior sagittal sinus (SSS) from the most anterior part of the SSS to sinus confluence. A neuroradiologist with 9 years’ experience (EM) manually segmented PSD on eight subjects. The first step was to threshold the images in Slicer (version 4.11.20200930)  placed in the brain parenchyma via a small burr hole, enabling online measurements of the static ICP (mean ICP) and pulsatile ICP  from the same ICP signal47. These ICP measurements did not involve CSF drainage or any placement of catheter to the CSF space. The MWA is computed over 6-second time windows and represents the pressure changes taking place during the cardiac cycle. Both the average values of MWA and mean ICP were computed, as well as the percentage of 6-second time windows with MWA ≥ 5 mmHg or mean ICP ≥ 15 mmHg. Notably, all ICP measurements reported here were obtained before interventions. During ICP monitoring, patients were kept in their beds, lying flat during overnight monitoring.The overnight ICP measurements included both assessment of the pulsatile and static ICP scores, as previously reported48 translated to Norwegian49. A PSQI-score ≤5 indicates good sleep quality50. The patients were asked to answer the questionnaire based on the last months’ sleep quality, not only sleep quality for the few days in relation to the MRI exams.Sleep quality was assessed by a PSQI questionnaire52, and her we particularly addressed the time to peak concentration in plasma.20/76 patients had plasma concentrations of tracer measured. The plasma concentrations of gadobutrol were estimated from quantifying gadolinium, as previously described in detail26 used different protocols to examine and segment PSD and the resulting volumes are not comparable. However, we used the same scanner, coil, protocol, and segmentation method to achieve comparable results within this study, even if the volumes per se are not directly comparable with other studies.Continuous data are presented as mean and standard deviation (SD). Normal distribution of the variables was assessed. Continuous data were compared using independent samples t-test. Correlations were determined by Pearson correlation test. The impact of different variables on PSD volume were assessed using multivariable regression analysis. The statistical analysis was performed using SPSS version 27 . Statistical significance was accepted at the 0.05 level (two-tailed). The method to segment PSD is not a standardised procedure. Two previous studiesFurther information on research design is available in the Peer Review FileSupplementary InformationReporting Summary


However, the changes in CSF sPDGFRβ levels and their role in blood–2, respectively. CSF total tau, phosphorylated tau181 (p-tau181), Aβ40, and Aβ42 were measured using the Simoa assay. Albumin and CSF sPDGFRβ were measured by commercial assay kits. CSVD burden was assessed by magnetic resonance imaging.A total of 158 individuals from the China Aging and Neurodegenerative Disorder Initiative cohort were selected, including 27, 48, and 83 individuals with a clinical dementia rating (CDR) score of 0, 0.5, and 1β = 0.314, p = 0.008) but not in the CDR 1–2 group . In the CDR 0–0.5 group, CSF sPDGFRβ exhibited a significant mediating effect between Aβ42/Aβ40 levels and Q-alb (p = 0.038). Q-alb, rather than CSF sPDGFRβ, showed a significant difference between individuals with or without CSVD burden. Furthermore, in the CDR 0.5 group, CSF sPDGFRβ was higher in subjects with progressive mild cognitive impairment than in those with stable mild cognitive impairment subjects (p < 0.001). Meanwhile, CSF sPDGFRβ was significantly associated with yearly changes in MMSE scores in the CDR 0.5 group  and CDR 0.5 (A+) subgroup .CSF sPDGFRβ was the highest level in the CDR 0.5 group. CSF sPDGFRβ was significantly correlated with the CSF/serum albumin ratio  in the CDR 0–0.5 group (We provide evidence that increased CSF sPDGFRβ is associated with BBB leakage in the early cognitive impairment stage of AD, which may contribute to cognitive impairment in AD progression.The online version contains supplementary material available at 10.1186/s13195-023-01199-5. Alzheimer’s disease (AD) is a major cause of dementia in elderly populations. There are numerous risk factors leading to AD occurrence and development, such as age, depression, obesity, diabetes, and hypertension –4. RecenPlatelet-derived growth factor receptor beta (PDGFRβ) is a type of tyrosine kinase receptor expressed by pericytes and vascular smooth muscle cells (SMCs) and usually serves as a biomarker of pericytes as PDGFRβ expression in pericytes is much higher than that in SMCs , 14. PDGThe China Aging and Neurodegenerative Disorder Initiative (CANDI) cohort recruited elderly participants with or without cognitive impairment for early diagnosis and prediction of AD in the Chinese Han population . In thisThe CANDI study was launched in 2018; it was a longitudinal study including individuals with normal cognition (CN), mild cognitive impairment (MCI), and dementia. All participants were recruited from the First Affiliated Hospital of the University of Science and Technology of China (USTC) in November 2018. CSF samples, plasma samples, imaging data, and cognition measurements were available and were used for this study .18F-florbetapir PET and/or CSF Aβ42/40 ratio were included in the A+ group. All cases in the CDR 1–2 group were A+, and only 3 cases were A+ in the CDR 0 group, but in the CDR 0.5 group, there were 20 A− cases and 28 A+ cases, using accepted cutoff values (0.06423) and/or visual judgment for 18F-florbetapir PET in the CANDI study [APOE genotypes were determined as described previously [For our study, 158 participants were from the CANDI cohort, and complete clinical data were required, after a detailed cognitive assessment, including the Mini-Mental State Examination (MMSE) and clinical dementia rating (CDR) scores . CSF sPDGFRβ  and albumin levels were measured by the corresponding commercial assay kits .CSF specimens from patients or controls in the above three groups were collected using lumbar puncture (LP) in the morning after an overnight fast. After confirming a clear appearance of the CSF sample, it was aliquoted in polypropylene tubes and stored at − 80 °C until measurements were taken. The CSF samples were vortexed and centrifuged at 10000×Noanticoagulative blood samples were collected by venipuncture during the collection of CSF specimens. The collected blood samples were centrifuged, and serum albumin concentrations were determined using a bromocresol green dye binding assay . The Q-alb value was calculated using the following formula:  × 1000.All images were acquired by using GE DISCOVER 750w 3.0T MRI scanner , including DWI/FLAIR/SWI and T2-weighted images, which were assessed by two experienced neuroradiologists blinded to clinical information. According to the recently described score for small vascular lesions , we ratep value < 0.05. For describing demographic data, the Wilcoxon signed-rank test was used for continuous variable intergroup comparisons, and chi-square analysis was used for categorical variables. AD biofluid biomarker measurements including Aβ42, Aβ40, p-tau, t-tau, and the Aβ42/Aβ40 ratio were compared using analysis of covariance (ANCOVA), with age, sex, and the APOE genotype as covariates. ANCOVA was also used to compare CSF sPDGFRβ and Q-alb levels between different cognition groups. A multiple linear regression model was adopted to evaluate the associations between CSF sPDGFRβ, Q-alb, and AD biomarkers. In multiple linear regression models, ratios of Q-alb much greater or lower than the triple standard deviation from the mean value were regarded as outliers and discarded. The Q-albumin ratio and concentration measures of CSF sPDGFRβ were ln-transformed when necessary, and the Shapiro–Wilk test was used to test the normality of the transformed data. Age, sex, and APOE genotype were included in multiple linear regression models as covariances to adjust the effects. The extent of pericyte injury contributing to BBB damage was determined using mediation analysis. This was based on a multiple linear regression model adjusted for age, sex, and APOE genotype. Ranked data, such as CSVD scores, are shown as the median of the interquartile range (IQR).The IBM SPSS 23.0 software for Windows , GraphPad Prism 7.0 , and R 4.0.4  were used for the analysis. Statistical significance in all two-sided tests was defined as p = 0.013). MMSE scores were significantly different among the three groups. As expected, there were more APOE e4 gene carriers in the CDR 0.5 group (45.83%) and CDR 1–2 group (63.86%) than in the CDR 0 (14.81%) group.As shown in Table p < 0.001). However, its level was reduced in the CDR 1–2 group compared to that in the CDR 0.5 A− group (p = 0.013) and CDR 0.5 A+ group (p = 0.023). In addition, we compared the CSF sPDGFRβ levels between subjects with a different APOE e4 gene carrier status or different sex. In the CDR 0, CDR 0.5, or CDR 1–2 groups, no significant difference was observed between APOE e4 gene carriers and non-carriers or males and females .The Q-alb exhibited no significant difference among the CDR 0, CDR 0.5 A−, CDR 0.5 A+, and CDR 1–2 groups , t-tau , and Aβ42/Aβ40 ratio . In patients with CDR 1–2, there were positive correlations between sPDGFRβ and p-tau , t-tau , Aβ40 , and Aβ42 . Q-alb was correlated with t-tau  in the CDR 0–0.5 group, whereas a significant correlation was observed between Q-alb and Aβ42/Aβ40  in the CDR 1–2 group  (28.5% for Aβ42/Aβ40). Meanwhile, there was no significant direct effect  or CSF sPDGFRβ-mediated effects  of Aβ42 or Aβ40 on Q-alb ratios. However, in the CDR 1–2 group, Aβ42/Aβ40 changed its CSF sPDGFRβ-mediated effect on BBB damage  to a direct effect on BBB damage .BBB breakdown and pericyte injury have been suggested to occur before cognitive impairment in patients . Meanwhip < 0.001), PVWMH (p < 0.001), DWMH (p = 0.035), and cerebral microbleeds (p = 0.028) among the CDR 0, 0.5, and 1–2 groups . The remaining 19 patients with stable disease pathology were defined as the stable mild cognitive impairment (SMCI) group . No significant difference was observed between the PMCI and SMCI groups regarding the baseline age, sex ratio, years of education, MMSE, APOE genotype, Aβ40, and Aβ42 levels (Table p = 0.004) and p-tau (p = 0.004) were significantly higher in the PMCI group, whereas the ratio of Aβ42/Aβ40 was lower in the PMCI group (p = 0.005) , while the correlation in the A− group was not statistically significant  group, and one patient met the diagnostic criteria for AD , including MCI or AD, with or without CSVD burden. Some interesting findings were observed: (1) the most significant increase in CSF sPDGFRβ levels was found in CDR 0.5 group; (2) in the CDR 0–0.5 group, CSF sPDGFRβ levels were significantly associated with Q-alb and partially mediated Aβ pathology-induced Q-alb change; (3) in the CDR 1–2 group, CSF sPDGFRβ was associated with AD core biomarkers, and no significant mediating effect was observed in the relationship between Aβ pathology and Q-alb; (4) CSF sPDGFRβ levels were not different between the groups with CSVD burden; and (5) in the CDR 0.5 group, the increased CSF sPDGFRβ levels were associated with accelerated cognitive decline.Elevation of CSF sPDGFRβ levels in humans and animal models indicates pericyte injury and is linked to BBB breakdown , 25–27. In the previous studies, Nation et al.  mainly fAlthough elevated CSF sPDGFRβ levels in AD have been verified in several independent studies , 21, 23,We also explored the possible relationship between pericyte damage and cerebral small vessel lesions in AD progression. CSF Q-alb was found to be significantly increased in individuals with CSVD burden ≥ 2, whereas CSF sPDGFRβ levels were similar among the groups with or without CSVD burden. Previous studies have suggested that cerebral small vessel lesions could cause cognitive impairment independent of Aβ . The preAPPsw/0 mouse model [Numerous studies have indicated that BBB breakdown is a marker of cognitive dysfunction , 24, andse model , it is rse model , 38, 39,se model , 41.Our study had some limitations. (1) The sample size was relatively small and was based on a single-center clinical cohort, with participants mainly recruited from eastern China. To obtain more accurate and general results, a larger population-based multicenter clinical study is needed. (2) Longer observation times and more follow-up cases are necessary to improve the statistical effectiveness of such longitudinal studies. (3) Other important biomarkers for BBB leakage, such as DCE-MRI data, were unavailable. In the future, a more comprehensive study should improve our understanding of the role of pericyte damage and BBB breakdown in AD progression.In conclusion, our study characterized the changes in CSF sPDGFRβ levels in different cognitive stages of AD and analyzed the relationship between CSF sPDGFRβ and AD core biomarkers, CSVD burden, and BBB breakdown. These results suggest that the contribution of pericyte injury to BBB damage varies during the progression of AD. The association between CSF sPDGFRβ levels and cognitive decline indicates that pericyte damage may promote the progression of AD.Additional file 1: Figure S1. Study flowchart. Figure S2. The potential effects of age, sex and APOE genotype on CSF sPDGFRβ levels.


To evaluate ancillary MRI features which may aid the identification of lateral temporal bone cephaloceles (LTBCs).T2W temporal bone and whole brain imaging according to a priori criteria by consensus, with emphasis on the relationship of any adjacent cerebrospinal fluid (CSF) cleft to the defect. The contents, location, and clinical features of the LTBCs were recorded.A retrospective cohort study analysed patients with MRI evidence of surgically confirmed spontaneous LTBCs as defined by intracranial contents traversing the tegmen tympani or mastoideum. Cases were identified from radiology and surgical databases. Two observers analysed three-dimensional Eighteen patients  with 20 surgically confirmed spontaneous LTBCs  were evaluated. A temporal lobe sulcus or other CSF cleft extending to or traversing the defect was identified in 19/20 (95%) cases. Isointense CSF tympanomastoid signal was present in 41.2% cases, whilst superior semi-circular canal dehiscence was found in 40% of cephaloceles. At least two MRI features of idiopathic intracranial hypertension were seen in 38.9% patients. Cephaloceles were most commonly centred on the tegmen tympani (55%). Meningoencephaloceles were present in 95% cases.A temporal lobe sulcus or CSF cleft extending to or traversing the defect may aid the identification of LTBCs. Isointense CSF tympanomastoid signal, superior semi-circular canal dehiscence and MRI features of idiopathic intracranial hypertension are only present in under half of LTBCs.The study details novel ancillary MRI features of LTBCs which may aid their identification. Although thought to be fairly uncommon, there are increasing reports of spontaneous temporal bone cephaloceles in recent international literature with a prevalence of up to 2% in healthy controls.Spontaneous lateral temporal bone cephaloceles (LTBCs) are characterised by the abnormal passage of intracranial contents into the middle ear and mastoid in the absence of trauma, surgery, tumours, or developmental defects. The condition has been frequently associated with idiopathic intracranial hypertension (IIH).Spontaneous LTBCs are thought to manifest from a multifactorial process involving increased intracranial pressure in conjunction with an anatomical structural predisposition at the site of pneumatisation. Patients are at risk of potentially life-threatening infections such as meningitis, so timely identification is required.Diagnosis of the condition is often difficult due to the non-specific constellation of presenting signs and symptoms. Commonly reported symptoms include hearing loss and cerebrospinal fluid (CSF) otorrhea, whilst rarer clinical presentations include seizures.T2W sequences are the mainstay for evaluation. However, detecting the herniation of intracranial contents may be challenging, particularly in the absence of a meningocele. It is therefore important to evaluate ancillary imaging features which aid the identification. In this regard, the configuration of adjacent sulcal spaces and the presence of tympanomastoid fluid may provide indirect evidence of a cephalocele, whilst superior semi-circular canal dehiscence (SSCD) and features of IIH are recognised associations. Recent studies have described certain clinical and radiological findings in spontaneous LTBCs but have not focussed specifically on the MRI features of this condition.Imaging has an important role in the prompt and accurate diagnosis of the condition and to prevent further complications. Whilst CT can identify temporal bone defects and soft tissue opacification, MRI is optimal for directly demonstrating a LTBC. Thin section spin echo or gradient recalled echo (GRE) The primary objective of the study was to determine ancillary MRI findings which aid the identification of surgically confirmed spontaneous LTBCs whilst the secondary objectives were to define their contents, location and clinical features.T2W imaging of the temporal bones. The study flowchart shown in Institutional approval (project number 13453) to conduct a service improvement project was obtained and patient consent was waived. This was a retrospective cohort study undertaken in a tertiary referral centre. Searches of a radiology imaging system and a dedicated surgical database were conducted from 01/01/2006 to 09/02/2022. The Boolean search comprised the keywords ‘cephalocele’ AND ‘petrous’ OR ‘temporal’ OR ‘ear’ OR ‘mastoid’. Exclusion criteria were cephaloceles secondary to trauma, surgery, tumours or developmental defects, cephaloceles at the petrous apex, previous tympano-mastoid surgery, those not confirmed surgically and those without three-dimensional (3D) During this period, 25 MRI studies were found from a dedicated surgical database and supplemented with 779 studies on an additional imaging search. Following this, 786 studies were excluded and MRI studies of 18 individual patients were included for analysis. Demographic data including age, gender and surgical history were collated. Surgical data including the operation date, site, surgical approach and type of cephalocele were collated.Clinical features including presenting signs and symptoms were collected. A diagnosis of IIH was confirmed according to clinical documentation of the patient meeting the Modified Dandy Criteria.T2W imaging and 3D T2W dedicated axial imaging of the temporal bones was performed on 1.5 Tesla (T) or 3T MRI systems. With respect to the 3D T2W axial imaging, CISS (constructive interference in steady state) was performed on 1.5T MAGNETOM Aera or Avanto scanners  in 16/20 (80%) cases, with one case (5%) performed on a 3T MAGNETOM Skyra scanner , whilst 3D T2W SPACE  was performed on 3T MAGNETOM Skyra scanners  in 3/20 (15%) cases. Whilst there was some variation between MRI scanners, the most frequently applied parameters were repetition time 5.8 ms, echo time 2.6 ms, one signal average, FOV 180 x 180 mm, slice thickness 0.7 mm, flip angle 660, acquisition matrix 320 × 320, 420 pixel bandwidth Hz/pixel for the CISS sequence and repetition time 1400 ms, echo time 155 ms, two signal averages, FOV 150 x 150 mm, slice thickness 0.7 mm, flip angle 1200, acquisition matrix 320 × 320, 290 pixel bandwidth Hz/pixel for the SPACE sequence.Axial whole brain Two head and neck radiologists with 30 years (SC) and 5 years (RS) experience analysed the MRI studies with the aid of multiplanar reconstructions and according to a priori criteria by consensus.≥2 MRI features of IIH was recorded  and location .MRI ancillary features and associations of LTBCs were evaluated. Firstly, the presence of either an adjacent temporal lobe sulcus or another CSF cleft overlying the temporal lobe was recorded if it extended to  or traverecorded .18,21 ® Excel for Mac 2021.Descriptive statistics were applied using Microsoft18 patients  with surgically confirmed spontaneous LTBCs were identified during the study period. Two patients had bilateral defects and the final cohort comprised 20 spontaneous LTBCs.T2W CSF signal cleft traversing the margin or centre of the defect was identified in 12/20 (60%) LTBCs. A high T2W CSF signal cleft, extending to the margin or central portion of the defect was detectable in 7/20 (35%) cases. Overall, a CSF signal cleft which either extended to or traversed the defect was found in 19/20 (95%) LTBCs (A high %) LTBCs . The sinT2W tympanomastoid signal abnormality demonstrated in all cases. In cases where 3D CISS imaging was performed, the tympanomastoid signal change was entirely CSF isointense in 7/17 (41.2%), partially CSF isointense in 7/17 (41.2%) or different to CSF signal in 3/17 (17.6%) cases.There was Eight of 20 (40%) cases in the cohort were found to demonstrate SSCD on MRI .At least two MRI imaging features of IIH were demonstrated in 7/18 (38.9%) patients. There was one patient (14.3%) with IIH imaging features without a corresponding clinical diagnosis. In total, nine (50%) patients were found to have clinically confirmed IIH.MRI demonstrated meningoencephaloceles in 19/20 (95%) cases. Cephaloceles were most frequently centred upon the tegmen tympani, either alone in 11/20 (55%) LTBCs or in combination with other sites in 16/20 (80%) of cases .Hearing loss was the most common presenting symptom, experienced by 16/18 (88.9%) patients. Seven (38.9%) patients presented with otorrhea, whilst three (16.7%) patients had meningitis. No patient presented with a seizure. The 20 cases were surgically confirmed using transmastoid (12/20), middle fossa (7/20) or combined (1/20) approach repairs. Two (11.1%) patients underwent bilateral surgical repairs.T2W CSF signal cleft was identified to extend to or traverse the bony defect in almost all (95%) surgically confirmed LTBCs on MRI and represents a key MRI feature which may aid their identification. Adjacent LTBC sulcal widening or asymmetric enlargement of an intracranial subarachnoid space was also seen in 85% of cases. Minor ancillary features such as tympanomastoid signal entirely isointense to CSF, SSCD and MRI features of IIH are only present in under half of LTBCs and their absence should therefore not deter the diagnosis.A high  Our study adds to this literature by evaluating associated MRI features in a cohort of surgically confirmed cases which may aid their detection. Previous studies investigating the MRI appearances of cephaloceles more generally have included descriptions regarding the associated traction of adjacent sulci towards a cephalocele. For example, this may manifest as an accompanying herniation of a pouch of CSF or asymmetric enlargement of the adjacent intracranial subarachnoid space. However, our study expands on this by specifically detailing the prevalence and description of a T2W CSF signal cleft extending to or traversing the defect in spontaneous LTBCs.The current radiological literature characterising the imaging features of spontaneous LTBCs is limited. Two recent studies investigating a cohort of spontaneous LTBCs predominantly focussed upon the clinical features and CT imaging findings. GRE 3D T2W sequences such as CISS are optimal for the analysis of the differing fluid composition of tympanomastoid fluid due to the utilisation of heavier T2 weighting and increased signal-to-noise ratios. Breen et al studied patients with temporal bone CSF leaks, although without cephaloceles in the majority of cases, and found that tympanomastoid signal isointense to CSF was 100% specific and 76% sensitive for the presence of a CSF leak. Interestingly, only 41.2% of our LTBCs demonstrated entirely CSF isointense tympanomastoid fluid. This discrepancy may relate to the partial or transient obstruction of the defect, in the presence of a cephalocele, resulting in an increased protein content of any tympanomastoid CSF leak. Secondly, SSCD and spontaneous LTBCs are both linked to thinning of the tegmen tympani and mastoideum. The high rate of SSCD (40%) in our cohort was similar to a recent study evaluating the prevalence in patients with lateral temporal bone cephaloceles, and much higher than the estimated prevalence of 0.7–4.0% in asymptomatic individuals. Whilst SSCD was absent in the majority of cases, the finding is of potential clinical importance since concomitant SSCD and LTBC repair can be performed using either a transmastoid or middle fossa approach. Finally, there is a known relationship between skull base cephaloceles and IIH. In our cohort, 38.9% of patients had MRI features of IIH, whilst half had a clinically confirmed diagnosis. This is higher than previously described in a retrospective case–control study investigating the rate of spontaneous intracranial meningoceles in IIH patients.Additional ancillary MRI features were chosen for evaluation on the basis of known associations. Firstly, unilateral tympanomastoid effusion is known to be associated with LTBCs, both clinically and on imaging studies. In addition, identifying the centre of the defect is another important factor in influencing surgical approach. The tegmen tympani was involved as the centre of defect, either alone or in conjunction with other sites, in the majority (80%) of LTBCs in our cohort. The rate of tegmen tympani involvement in our study is towards the higher end compared to recent studies. The non-specific constellation of clinical presenting features in patients with spontaneous LTBCs presents a diagnostic challenge. Hearing loss was the most common symptom and in line with the rate in other recent studies. CSF otorrhea and meningitis are recognised clinical presentations and featured in our cohort, whereas seizures did not.MRI can also have an important role in delineating the intracranial contents within a cephalocele. Meningoencephaloceles accounted for the majority of cephaloceles in the study. No previous studies have delineated the type of cephalocele using MRI in a cohort of patients with spontaneous LTBCs. The finding is of particular importance since the type of cephalocele has implications on pre-operative planning and outcome. However, the body mass indices in most patients were not available. Secondly, the scoring of MRI features was performed by consensus rather than by multiple observers. Whilst a priori criteria were applied, the subjective nature of these observations would have benefited from independent scoring and calculation of agreement statistics. Thirdly, our proposed ancillary features have not been fully evaluated for their diagnostic utility since they were not applied to a control group. Finally, the low number of patients in our study somewhat limits the overall generalisability of the results.The authors appreciate there are some limitations to the methodology. Firstly, inherent to the nature of the retrospective study, there were some data points which were not possible to complete. For example, spontaneous temporal bone cephaloceles have been significantly associated with obesity.T2W CSF signal cleft extends to or traverses the temporal bone defect in almost all cases of surgically confirmed spontaneous LTBCs on MRI, whilst entirely CSF isointense tympanomastoid signal, SSCD and MRI features of IIH are only present in under half of LTBCs. Interrogating the MRI for CSF clefts at the interface of the temporal lobe and temporal bone tegmen may aid the detection of LTBCs in the appropriate clinical setting.In conclusion, a


The aim of this study was to evaluate the performance of the BioFire® FilmArray® Meningitis Encephalitis panel (MEP) for the detection of bacterial and fungal pathogens compared with cerebrospinal fluid (CSF) cultures and other parameters to determine the predicted value of a positive result (PPV).This study is a retrospective chart review of patients with positive MEP from 10/2016–9/2022 at the University of Kentucky. Results of the MEP, culture, cellularity, protein, and glucose were collected using an electronic medical record search. Chart review was performed to collect demographic data, presentation, and test indication if a bacteria or fungus was identified. MEP was considered true positive (TP) if it was confirmed by CSF culture. It was classified a likely TP based on a positive CSF Gram stain, blood culture, other CSF findings consistent with clinical meningitis. It was considered false positive (FP) if the MEP was discordant with CSF and clinical findings. Statistical analysis was performed.Table 1. Results were summarized as TP, likely TP or FP by the pathogen detected (Table 2). The majority of results [106(92.2%)] were classified as TP or likely TP whereas 9 (7.8%) were classified as FP. 28/37 (75.7%) of patients with negative CSF cultures received at least one day of antibiotics prior to lumbar puncture. One third of the FP results were S. agalactiae. FP were statistically different from those classified as positive for cellularity, glucose and protein (Table 3).Of the 11,969 panels tested, 132 (1.1%) were positive for bacterial or fungal pathogens. Seventeen positive repeats were excluded. Clinical characteristics, outcomes, and CSF findings for 115 patients with positive MEP for bacterial and fungal organisms are shown in S. agalactiae. Interestingly, 27.4% (29/106) cases (excluding the FP) would not have had a pathogen definitively identified if MEP was not used. The positive CSF and blood culture rates were higher for cryptococcal meningitis. The median CSF cell count and protein were the highest among patients with S. pneumoniae meningitis. Inpatient mortality was uncommon.The PPV of MEP ranged from 78.6-100% based on an organism. Three-quarters of negative CSF cultures were likely from a prior antibiotic exposure. FP MEP were most common for All Authors: No reported disclosures


Osteoarticular infections (OAI) have been commonly treated with prolonged intravenous (IV) antimicrobials. The Oral versus Intravenous Antibiotics for Bone and Joint Infection (OVIVA) trial demonstrated that oral (PO) antibiotic therapy was noninferior to IV antibiotics in the treatment of OAIs. We surveyed Infectious disease (ID) physicians to see how often they used PO antibiotics in the treatment of OAIs and the barriers to using PO antibiotics.An EIN survey was sent to 1475 ID physicians. The survey had 9 questions pertaining to antibiotic prescribing patterns in the treatment of OAIs. The questions were mostly multiple choice, Yes/No questions with an area provided for free text. Definitive oral antibiotic therapy was defined as switching to PO antibiotics within 2 weeks of starting antibiotics.Staphylococcus aureus infections followed by doxycycline/minocycline. Amoxicillin/ cefadroxil/ cephalexin was used for treatment of streptococcal infections and fluoroquinolones were used as definitive treatment for infections caused by Gram-negative organisms. The most common reasons for not transitioning to PO antibiotics included non-susceptible pathogen, comorbidities preventing therapeutic drug levels and concern about adherenceThere were 413 respondents who treated OAIs and responded to the survey. A plurality of respondents 150/413 (36%) switched from IV to PO antibiotics after 4 weeks of IV therapy. 129/413 (31%) switched to oral antibiotics as definitive treatment . PO antibiotics were used as definitive therapy most often for diabetic foot osteomyelitis and native joint septic arthritis . Trimethoprim-sulfamethoxazole was most often used as definitive therapy for For the following infections, how often do you use oral antibiotics as definitive therapy?A sizeable portion of ID physicians utilize PO antibiotics for the management of OAIs, although significant practice variation exists regarding the timing of IV to PO switch.Philip M. Polgreen, MD, Eli Lilly: Case adjudication for a clinical trial Keenan L. Ryan, PharmD, PhC, PharmCon: Honoraria


The efficacy of intermittent cerebrospinal fluid (CSF) drainage compared with that of continuous CSF drainage in patients with subarachnoid hemorrhage (SAH) remains undetermined to date. Therefore, we investigated whether intermittent CSF drainage is effective in reducing secondary chronic hydrocephalus (sCH) after aneurysmal SAH.Overall, 204 patients (69 men and 135 women) treated for aneurysmal SAH between 2007 and 2022 were included in this study. Following SAH onset, 136 patients were managed with continuous CSF drainage, whereas 68 were managed with intermittent CSF drainage. Logistic regression analyses were used to calculate the age-adjusted and multivariate odds ratios for the development of sCH. The Cox proportional hazards regression model were used to compare the effects of intermittent and continuous CSF drainage on sCH development.Overall, 96 patients developed sCH among the 204 patients with SAH. In total, 74 (54.4%) of the 136 patients managed with continuous CSF drainage developed sCH, whereas 22 (32.4%) of the 68 patients managed with intermittent CSF drainage developed sCH. This demonstrated that the rate of sCH development was significantly lower among patients managed with intermittent CSF drainage. Compared with continuous CSF drainage, intermittent CSF drainage exhibited a multivariate odds ratio  of 0.25 (0.11–0.57) for sCH development. Intermittent CSF drainage was more effective  in patients with severe-grade SAH than in those with mild-grade SAH . Intermittent CSF drainage was ineffective in patients with acute hydrocephalus , but it was effective in patients without acute hydrocephalus .Compared with continuous CSF drainage, intermittent drainage is more effective in reducing sCH after aneurysmal SAH. Although intermittent drainage was ineffective in cases of co-occurrence of acute hydrocephalus, it was effective in reducing sCH development regardless of the severity of initial symptoms at SAH onset. Subarachnoid hemorrhage (SAH) is recognized as one of the most lethal disorders, and SAH survivors often have a low quality of life. The poor prognosis of this condition is mainly attributed to various comorbidities, including cerebral infarction due to cerebral vasospasm and secondary chronic hydrocephalus (sCH) after SAH. Notably, regarding the prevalence of sCH, < 50% of the patients with aneurysmal SAH have been reported to have sCH –12. At tMoreover, according to Rao et al., compared with continuous cerebrospinal fluid (CSF) drainage and gradual weaning, intermittent CSF drainage and rapid weaning of external ventricular drainage were reported to be associated with a lower number of patients with sCH requiring permanent ventriculoperitoneal shunt (VPS) implantation . FurtherWe retrospectively identified 278 consecutive patients with SAH who were admitted to Nagoya City University between February 2007 and November 2022. Of them, 27 patients died in the acute phase of SAH onset, 1 was unknown origin SAH, 8 had not received any treatments for ruptured aneurysms within 72 h of admission, 4 were treated with both microsurgical clipping and coil embolization, 30 did not undergo CSF drainage, and 4 were managed with both intermittent and continuous CSF drainage. Finally, 204 patients were enrolled in this study, including 136 patients managed with continuous CSF drainage and 68 patients managed with intermittent CSF drainage , duration of CSF drainage, and time from the onset of SAH to the development of sCH was obtained from the medical records of the patients. Other clinical data collected were as follows: age at SAH onset, sex, medication status, World Federation of Neurological Surgeons (WFNS) scale grade for initial symptoms of severity at SAH onset, Fisher rating scale grade at admission, and treatment of the ruptured aneurysm . The ruptured aneurysms were classified according to their location as follows: middle cerebral artery (MCA), 39; anterior communicating artery (ACoA), 57; anterior cerebral artery (ACA), 11; internal carotid-posterior communicating artery (IC-PCoA), 45; other internal carotid artery (ICA), 17; posterior cerebral artery (PCA), 3; basilar artery (BA), 6; BA–superior cerebellar artery (BA-SCA), 1; vertebral artery (VA), 18; VA–posterior inferior cerebellar artery (VA-PICA), 7. The locations of the aneurysms were divided into five categories: MCA, ACA (including ACA and ACoA), IC-PCoA, ICA, and posterior circulation . Concomitant acute hydrocephalus was defined as patients with ventricular enlargement on CT scan and rapidly progressive loss of consciousness requiring immediate CSF drainage via external ventricular drainage, and sCH was defined as patients with progressive ventricular enlargement on CT scan and progressive symptoms, such as impaired consciousness, requiring CSF shunt surgery if CSF removal from the ventricles or lumbar subarachnoid space was not performed at least 2 weeks after the onset of SAH. Acute hydrocephalus is often obstructive hydrocephalus, while sCH after SAH is usually classified as non-obstructive hydrocephalus.2O by adjusting the height of the drainage disk open to atmospheric pressure before treatment of ruptured cerebral aneurysms in order to reduce the risk of rebleeding. Further, after treatment, the pressure was controlled down to to approximately 10 cm H2O. Notably, the height of the drainage disk should be correctly adjusted when measuring the CSF drainage volume. If the intracranial pressure does not rise for several days after the SAH onset, CSF drainage method is switched from external ventricular to external lumbar drainage.Patients with concomitant acute hydrocephalus were immediately treated with emergency external ventricular drainage to control intracranial pressure; subsequently, treatments for ruptured cerebral aneurysms were performed. Intracranial pressure was controlled to approximately ≤ 20 cm H2O, and the drainage was clamped until the next session. During intermittent CSF drainage, if the patients were in good condition, i.e., if they were conscious and able to move, they were allowed to leave the bed with the drain clamped and actively engage in rehabilitation interventions, such as standing and gait training. In contrast, during continuous CSF drainage, the patients remained in the bed and uderwent rehabilitation therapies to prevent contracture and maintain muscle strength in the extremities and trunk. Further, we routinely managed the gradual weaning of CSF drainage. Specifically, we considered drainage weaning approximately 2 weeks after the onset of SAH, when the acute phase of SAH, including cerebral vasospasm, was over. Further, when it was determined that CSF drainage was no longer required  of < 0.05 was considered to be statistically significant. R software  was used for all statistical analyses.We examined the relationship between sCH and the following factors: CSF drainage method (continuous or intermittent), concomitant acute hydrocephalus, age, sex, location of ruptured cerebral aneurysms, WFNS scale grade, Fisher rating scale grade, microsurgical clipping or coil embolization, cerebral vasospasm, and the use of medications (cilostazol and statin) to prevent delayed cerebral infarction due to cerebral vasospasm. Logistic regression analysis was conducted to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs) for the development of sCH. The continuous variable of age at the onset of SAH was used to adjust all analyses. Further, multivariate analyses were performed after adjusting for the above-mentioned factors to assess the effect of modification and interaction between the CSF drainage method and sCH development. For continuous variables, Wilcoxon rank-sum test was used to compare mean values and standard deviations (SDs). Chi-square test was used to compare the proportions of the location of ruptured cerebral aneurysms and WFNS scale grade, etc. between the intermittent and continuous CSF drainage methods. In addition, to compare the intermittent and continuous drainage, Kaplan–Meier curves in the Cox proportional hazard regression model were plotted to demonstrate the probability of not developing sCH within 180 days after the onset of SAH. They were also evaluated after stratification based on the presence of concomitant acute hydrocephalus and concomitant intracerebral hematomas, severe initial symptoms at SAH onset, and initial pressure setting at the time of CSF drainage placement. In the present study, severe symptoms were defined by WFNS grade IV or V, whereas mild symptoms were defined by WFNS grades I–III. A high initial pressure setting was defined as 12.0 cmH2O in the continuous CSF drainage group, and 10.0 and 6.0–20.0 cmH2O in the intermittent drainage group, with significant differences (P = 0.02). The two groups (continuous and intermittent CSF drainage) showed significant differences in terms of acute hydrocephalus and cerebral vasospasm prevalence, cilostazol and statin use, and WFNS scale grade for symptom severity; conversely, no significant differences were found in terms of the location of ruptured cerebral aneurysms and Fisher rating scale grades. Among 204 patients with aneurysmal SAH, 103 were treated with microsurgical clipping and 101 with coil embolization. Notably, there were no statistically significant differences in terms of these treatments between the two groups.Table Overall, 96 (47.0%) of 204 patients treated with aneurysmal SAH developed sCH at an average of 35.1 ± 19.8  days after SAH. Further, 74 (54.4%) of 136 patients managed with continuous CSF drainage developed sCH at 35.2 ± 18.6 (15–114) days after SAH, whereas 22 (32.4%) of 68 patients managed with intermittent CSF drainage developed sCH at 34.8 ± 24.0 (17–132) days after SAH.P = 0.005). Furthermore, the presence of concomitant acute hydrocephalus  as well as the WFNS scale grades IV  and V  were associated with a significantly higher risk of sCH development. Compared with ruptured aneurysms in MCA, those in ACA, IC-PCoA, and posterior circulation were associated with a significantly higher risk of sCH development. Further, regarding the risk of sCH development in terms of treatment, there was no statistically significant difference between microsurgical clipping and coil embolization.As shown in Table The Kaplan–Meier curve for the probability of not developing sCH within 180 days after the onset of SAH are presented in Fig. P = 0.015) and 0.20 , and those in the mild-grade SAH were 0.66  and 0.33 , respectively.Moreover, in the subgroup analyses, the intermittent drainage had a lower tendency to cause sCH in both subgroups—severe-grade SAH  and mild-grade SAH —although the probability of developing sCH was higher and the effect of intermittent CSF drainage was greater in the severe-grade SAH subgroup than in the mild-grade SAH subgroup Fig. . The ageP = 0.308) and 8.37 , and those in the subgroup without acute hydrocephalus were 0.32  and 0.11 .In the acute hydrocephalus subgroup Fig. , the proP = 0.001) and 0.02 , and those in the subgroup of low initial pressure of CSF drainage were not significant.In the subgroup of high initial pressure of CSF drainage Fig. , intermiP = 0.007) and 0.22 , although those in the subgroup of concomitant intracerebral hematomas were not significant.In the subgroup of concomitant intracerebral hematomas, i.e., grade 4 on Fisher CT rating scale at admission Fig. , the proThe present study found that intermittent CSF drainage is more effective than continuous CSF drainage in reducing the development of sCH after aneurysmal SAH. To the best of our knowledge, only one previous study has demonstrated the effectiveness of intermittent CSF drainage. In the study by Rao et al. , intermiAlthough the mechanism of the effectiveness of intermittent CSF drainage in reducing sCH development is unknown, storage of CSF in the subarachnoid space during periods of no drainage would help prevent arachnoid membrane adhesion. There is consensus that extensive adhesions in the subarachnoid space are the main pathogenesis of sCH after SAH , 21–24. Furthermore, this study confirmed that increasing age, severe initial symptoms, a large amount of diffuse subarachnoid hematoma, the presence of concomitant acute hydrocephalus, and the location of ruptured cerebral aneurysms in ACA, IC-PCoA, and posterior circulation were significantly associated with the development of sCH, and these results are consistent with those of previous studies –14. HoweThis study has several limitations. First, there are different historical backgrounds on the treatment of SAH, including CSF drainage, as mentioned above. Advances in endovascular therapy and frequency of use of cilostazol and statins markedly differ between before and after 2012, and their influences should not be overlooked. Second, 74 patients (26.6%) of 278 consecutive patients with SAH were excluded from the present study due to various reasons. Third, there was a difference in the number of cases between the two groups, with 136 patients managed with continuous CSF drainage and 68 patients managed with intermittent CSF drainage. This difference may be attributed to selection bias. Finally, because this study was conducted at a single institute in a retrospective fashion, we could not establish a direct causal relationship between intermittent CSF drainage and the development of sCH. Thus, further randomized multicenter controlled trials are warranted to assess the effectiveness of new interventions or treatments.The results of the present study indicate that intermittent CSF drainage after SAH is associated with fewer cases of sCH than continuous CSF drainage. Although intermittent CSF drainage was ineffective in SAH with concomitant acute hydrocephalus, it was effective in reducing sCH development regardless of the severity of the initial symptoms at the onset of SAH. Further studies are required to understand the mechanisms of the effectiveness of intermittent CSF drainage in reducing sCH development after SAH.


Leptomeningeal metastases (LM) were rare in gastric cancer (GC), and GC patients with LM (GCLM) generally suffer from poor prognosis. Nevertheless, the clinical utility of cerebrospinal fluid (CSF) circulating tumor DNA (ctDNA) was underinvestigated in GCLM.We retrospectively studied 15 GCLM patients, and all patients had paired primary tumor tissue samples and post-LM CSF samples while 5 patients also had post-LM plasma samples. All samples were analyzed using next-generation sequencing (NGS), and the molecular and clinical features were correlated with clinical outcomes.P = 0.015), more somatic mutations (P = 0.032), and more copy-number variations (P < 0.001) than tumor or plasma samples. Multiple genetic alterations and aberrant signal pathways were enriched in post-LM CSF, including CCNE1 amplification and cell cycle-related genes, and CCNE1 amplification was significantly associated with patients’ overall survival (P = 0.0062). More potential LM progression-related markers were detected in CSF samples than in tumor samples, including PREX2 mutation (P = 0.014), IGF1R mutation (P = 0.034), AR mutation (P = 0.038), SMARCB1 deletion (P < 0.001), SMAD4 deletion (P = 0.0034), and TGF-beta pathway aberration (P = 0.0038). Additionally, improvement in intracranial pressure (P < 0.001), improvement in CSF cytology (P = 0.0038), and relatively low levels of CSF ctDNA (P = 0.0098) were significantly associated with better PFS. Lastly, we reported a GCLM case whose CSF ctDNA dynamic changes were well correlated with his clinical assessment.CSF had higher mutation allele frequency (CSF ctDNA could more sensitively detect molecular markers and metastasis-related mechanisms than tumor tissues in GCLM patients, and our study sheds light on utilizing CSF ctDNA in prognostic estimation and clinical assessment in GCLM.The online version contains supplementary material available at 10.1186/s12967-023-04077-8. The incidence of leptomeningeal metastases (LM) was 5–8% in cancer patients, and patients with LM are usually associated with poor prognosis, suffering from severe symptoms such as headache, nausea, and vomiting. Adenocarcinoma is the major form of LM, and breast, lung, and skin are the most common primary sites of tumorigenesis . In contPlasma circulating tumor DNA (ctDNA) is tumor-derived cell-free DNA (cfDNA) that was released into the blood circulatory system, and plasma ctDNA has been widely used as a non-invasive tool to characterize tumor genomics , 8. HoweIn the current study, we recruited 15 GCLM patients and conducted next-generation sequencing (NGS) analysis of 425 cancer-relevant genes on matched primary tumor, plasma, and CSF samples. The detected genetic alterations were compared among different sample types, and the molecular results were then correlated with patients’ survival to investigate the prognostic factors related to LM. Overall, our study aimed to elucidate the clinical utility of CSF in GCLM.A total of 15 GCLM patients were diagnosed and treated in the Department of Neurology, The Second Hospital of Hebei Medical University  between July 2016 and November 2020. All patients provided signed informed consent and the study protocol was approved by the Research Ethics Committee of The Second Hospital of Hebei Medical University. The LM diagnosis was confirmed using CSF cytology in all 15 patients. Typical imaging of LM was identified as linear or micro-nodular pial enhancement in magnetic resonance imaging (MRI) by two experienced radiologists. Approximately 5 mL of CSF from each patient was collected via lumbar puncture for cytology examination and NGS. Meanwhile, 10 mL blood samples were collected for control and plasma ctDNA detection. Fifteen primary stomach lesion samples were available from the specimen repository. All primary tumor tissue, post-LM plasma samples, and post-LM CSF samples underwent NGS of 425 cancer-relevant genes, and white blood cells were used as normal controls to filter out germline mutations  tumor, freshly frozen CSF, and whole blood samples were collected for genomic profiling. All FFPE tissues were reviewed by histopathological assessment. Tissue DNA was extracted using the QIAamp DNA FFPE tissue kit  following the manufacturer’s instructions. Similar procedures were used for cfDNA extraction from whole blood and CSF. Total DNA from plasma and freshly frozen CSF was extracted by QIAamp Circulating Nucleic Acid Kit . The quantity and quality of the extracted DNA were evaluated using a Qubit 3.0 fluorometer and Nanodrop 2000, respectively (Thermo Fisher Scientific).Sequencing libraries were prepared using the KAPA Hyper Prep Kit (KAPA Biosystems) according to the manufacturer's suggestions for different sample types. In brief, 1 μg of fragmented genomic DNA underwent end-repairing, A-tailing, and ligation with indexed adapters sequentially, followed by size selection using Agencourt AMPure XP beads (Beckman Coulter). Hybridization-based target enrichment was carried out with the Geneseeq Prime™ panel  covering 425 cancer-associated genes, and xGen Lockdown Hybridization and Wash Reagents Kit (Integrated DNA Technologies). Captured libraries by Dynabeads M-270 (Life Technologies) were amplified in KAPA HiFi HotStart ReadyMix (KAPA Biosystems) and quantified by qPCR using the KAPA Library Quantification Kit (KAPA Biosystems) for sequencing. Enriched libraries were sequenced on HiSeq X10 sequencing system  with 150 bp pair-end reads.Sequencing data were processed as previously described . In brieP values that were smaller than 0.05 were considered statistically significant.Fisher’s exact test was used to compare the frequency of genetic alterations between groups, and it was carried out using the SPSS for Windows software package . Relative ctDNA abundance was defined as Max ctDNA AF*cfDNA concentration (ng/mL). Progression-free survival (PFS) was defined as the time between diagnosis of LM and disease progression or patient death, and overall survival (OS) was defined as the time between the diagnosis of GC and patient death. Prognosis data were analyzed by Kaplan–Meier curve and log-rank test . Statistical analyses were performed using the R (v4.2.1). Two-tailed The clinical characteristics of the enrolled 15 GCLM patients were summarized in Table TP53 was the most commonly mutated genes in both tumor tissue and CSF, with 100% detection consistency between the two types of samples  vs 26.7% (4/15), 53.3% (8/15) vs 13.3% (2/15), and 26.7% (4/15) vs 13.3% (2/15), respectively  and missense mutations (P = 0.032) than tumor tissue samples , RTK/RAS pathway (P = 0.050), and PI3K pathway (P = 0.050) , IGF1R mutation (P = 0.034), AR mutation (P = 0.038), SMARCB1 deletion (P < 0.001), SMAD4 deletion (P = 0.0034), and TGF-beta pathway aberration (P = 0.0038)   showed no abnormality; however, gadolinium-enhanced T1-weighted MRI of the brain showed leptomeningeal contrast enhancement, which was most prominent over the superior aspect of the temporal lobe  to phosphorylate and inactivate Rb, resulting in activating E2F-mediated transcription and promoting the transition from G1 to S phase to initiate DNA synthesis [CCNE1 amplification has been reported in breast, ovary, gastric, and endometrial cancers and was related to poor prognosis [CCNE1 amplification is found in 11–12% of gastric cancers, and it was suggested to be associated with liver metastasis in gastric carcinoma [CCNE1 amplification had shorter OS. This indicates that CCNE1 amplification may serve as a prognostic marker for GCLM, and patients who are positive for CCNE1 amplification may need to adjust their treatment regimen accordingly.Many previous experimental studies focus on the survival of tumor cells in CSF after leptomeningeal metastasis of solid tumors. Nevertheless, the underlying mechanism of meningeal metastasis of solid tumors is still unclear. Fan et al. reported the potential implication of cell cycle pathway changes in lung cancer leptomeningeal metastasis , which iynthesis . CCNE1 arognosis –35. CCNEarcinoma . Our datWe discovered that aberrations in SMAD4 or TGF-β pathways were associated with worse clinical outcomes. During cancer progression, TGF-β signaling pathway promotes tumor progression by promoting epithelial-mesenchymal-transition (EMT) invasion and augmenting cellular transformation in advanced stages of malignancy . SMAD4 iERBB2 amplification was detected in the CSF samples of 4 patients, and these patients may thus benefit from HER2-targeted therapies. Additionally, for GC patients without radical surgery or metastatic cancer, comprehensive treatment using systemic anti-tumor drugs has become accepted treatment regimens, including chemical drugs, targeted drugs, and immune checkpoint inhibitors. Notably, anti-PD-1 monoclonal antibody combined with chemotherapy has become the new standard of first-line treatment for advanced metastatic GC. The combination of anti-PD-1 therapy with stereotactic radiosurgery was also shown to be effective in GC patients with brain metastases [In our cohort, most patients received intrathecal chemotherapy, some patients received systemic chemotherapy and stereoscopic radiotherapy, while none of the patients received targeted therapy or immunotherapy. The resulting median progression-free survival was 12 weeks. Previous studies found that HER2-positive GC patients had increased incidence of brain metastases , and simtastases . In our There are some limitations of our study. Firstly, the GCLM cohort size was relatively small given the rareness of the samples. Secondly, the study was conducted in a single medical center, so the results of this study need to be validated in future studies. Thirdly, due to the rarity of the sample, we cannot find a good external GCLM patient cohort that contains NGS data of both primary tumor and CSF samples. Fourthly, since both tissue and CSF samples were analyzed by NGS, there might be some potential technical bias in mutation/CNV detection between these two samples. Therefore, future studies using alternative approaches, such as droplet digital PCR (ddPCR), are necessary to validate our data, especially the CSF results. Lastly, our cohort lacked paired post-LM tissue samples and time-series CSF samples, which is important for further validations.In conclusion, we performed NGS analyses of matched primary tumor tissue samples, post-LM plasma samples, and post-LM CSF samples from 15 GCLM patients, and we correlated the molecular features with clinical outcomes. We found that CSF could more sensitively detect molecular markers and metastasis-related mechanisms, suggesting a profound potential for using CSF ctDNA in prognostic estimation and clinical assessment in GCLM patients.Additional file 1: Fig. S1 The overview of patient cohorts and the study plan. Fig. S2 The comparison of different types of cancer samples in 15 GCLM patients. (A) The consistency of detected mutations between CSF and tumor tissue samples in each patient. (B) The comparison of the mean allele frequency (AF) of all the mutations between CSF and tumor tissue samples. (C) The comparison of the genetic mutations among primary tumor, post-LM CSF, and post-LM plasma samples for patients 1, 2, 4, 7, and 10. Fig. S3 The phylogenetic analysis of the primary tumor and post-LM CSF samples in 15 GCLM patients. For each patient, the shared mutations were shown in black (stem), the primary tumor unique mutations were shown in blue (branch), and the CSF unique mutations were shown in red (branch). Fig. S4 The molecular characteristics that were associated with GCLM clinical outcomes. (A-B) The Kaplan-Meier curves of PFS in GCLM patients stratified by PTPN13 mutation status (A) or ERBB2 mutation status (B) that was assessed by tumor tissue samples. (C-H) The Kaplan-Meier curves of PFS in GCLM patients stratified by PREX2 mutation status (C), IGF1R mutation status (D), AR mutation status (E), SMARCB1 deletion status (F), SMAD4 deletion status (G), or TGF-beta pathway aberration status (H) that was assessed by CSF samples. PFS, progression-free survival. Fig. S5 The Kaplan-Meier curve of PFS in GCLM patients stratified by the treatment status prior to LM. Table S1 The clinical characteristics of the 293 primary gastric cancer patients from the TCGA database. Table S2 The clinical characteristics of the 15 GCLM patients. Table S3 The comparison of mutation/pathway aberration between patients with and without prior LM treatments.


P = 0.110, age >44 HR, 1.80; P = 0.056) but lower relapse risk . There were no differences in CRS, aGVHD or cGVHD. We found no difference in outcomes based on the donor-recipient relationship. No differences were found based on HLA match grade or DRB1 match status. Increasing donor age was associated with lower relapse risk but higher NRM, resulting in no difference in OS based on donor age. Other donor factors including relationship , CMV status, donor sex, HLA match grade, and DRB1 status were not associated with outcomes.Here we describe a retrospective analysis of outcomes in 299 patients who underwent peripheral blood haplo-HCT with PTCy from July 2009 through May 2021 and their association with donor characteristics. Patients had mostly acute leukemias and high or very high DRI. Multivariate analyses were conducted examining OS, NRM, relapse, cytokine release syndrome, acute and chronic GVHD. Donor characteristics included age, sex, relationship, ABO status, CMV status, and HLA match grade. Our analysis revealed increasing donor age was associated with higher NRM (compared to age <30; age 30–44 HR, 1.65;  Allogeneic hematopoetic cell transplant (HCT) is an important therapy for a variety of hematologic malignancies and non-malignant hematologic disorders, and for many patients it represents the only curative intent treatment. An increasingly utilized source for hematopoetic stem cells is HLA haploidentical-related donors , 2. ImprIn the matched-unrelated donor setting, younger donor age is associated with improved transplant-related and non-relapse mortality (NRM) –11. In tThere has been more variability in reports regarding the effect of donor relationship/kinship on transplant outcomes. One study suggested improved OS and relapse-free survival (RFS) with children relative to parental donors, though not controlled for donor age . Wang etOther potential variables of interest in selecting a haploidentical donor include degree of HLA disparity, specific HLA allele mismatches, blood group ABO compatibility, and donor/recipient cytomegalovirus (CMV) status. The degree of total HLA disparity has not been shown thus far to be of importance in haplo-HCT –24. HoweThe graft source in these previously described populations has been predominantly, or in some cases entirely, bone marrow-derived grafts. A uniform population of all peripheral blood grafts has yet to be described. There are important differences in the cellular composition of peripheral blood stem cells (PBSCs) relative to bone marrow, including much higher T cell content, that may alter the biology of HCT. Prior studies have identified higher rates of GVHD with PBSCs , 15, 25.Institutional review board approval was granted for this retrospective study of 324 consecutive patients who underwent haploidentical transplant from July 2009 to June 2021. Donors could be either first-degree or second-degree relatives. Patient-donor pairs who were not both HLA typed at the HLA-A, HLA-B, HLA-DRB1, HLA-C, and HLA-DQB1 loci at a high-resolution level were excluded. In total, 299 patients meet inclusion criteria for the final analysis. Haplo-HCT was performed after either myeloablative or nonmyeloablative conditioning. T-cell-replete peripheral blood grafts were administered on Day 0. GVHD prophylaxis consisted of PTCy on days +3 and +4, mycophenolate mofetil on day +5 to +35, and Tacrolimus on day +5 to +180. A subset of patients received itacitinib on day +3 to day +100 on a clinical trial (NCT03755414).The primary study outcomes were overall survival (OS), relapse, and non-relapse mortality (NRM). OS was defined as the time from haplo-HCT to death by any cause. RFS was defined as the time from haplo-HCT to death by any cause or relapse, whichever occurred first. NRM was defined as death in the absence of any relapse or progression. Relapse and NRM were considered competing risks. Acute GVHD was graded using the Glucksberg grading system and classified as any (grades I–IV) or severe (grades III–IV) . Chronicp-value of 0.05. All the analyses were performed using SAS 9.4 .Patient and donor characteristics were summarized using counts and frequencies for categorical variables or means and standard deviations for continuous variables. The distributions of OS across subgroups of interest were described using Kaplan-Meier product limit methods and compared by log-rank tests. Cumulative incidences of relapse and non-relapse mortality (NRM) were estimated using Gray’s sub-distribution method to account for competing risks. Death without relapse was considered a competing risk for relapse, while relapse was considered a competing risk for NRM. Given that relapse and NRM were in opposing directions for some key variables, the composite endpoint of relapse-free survival was unlikely to be informative and thus not included. Multivariate analyses were performed to assess the association between patient/donor characteristics and outcomes using Cox proportional hazards models for OS and using Gray’s sub-distribution regression for relapse/NRM, while using the backward selection procedure to identify independent prognostic factors. The assumption of proportional hazards was assessed graphically based on residuals out of the corresponding regression models. These potential factors included patient age, disease risk index by Armand criteria, HCT comorbidity index, CMV status, disease status at transplant, and myeloablative or nonmyeloablative conditioning. We included donor age as a continuous variable in the Cox regression model, but a linear relationship was not observed. Therefore, we classified donor age using cutoffs of less than 30, 30–44, and 45 or greater per protocol. We compared parents vs. siblings for patients 40 years of age or younger and children vs. siblings for patients over 40 years of age. All tests were two-sided and significance was set at a In total, 299 patients underwent peripheral blood haplo-HCT and high-resolution HLA typing at the above mentioned loci from July 2009 to June 2021. Mean patient follow up was 20.7 months (0.2–119). Baseline demographics of recipients and donors, as well as other transplant characteristics are shown in Table P = 0.038, age > 65 HR, 2.42; P < 0.001), DRI , HCT CI , KPS > 80 , disease status at transplant , and myeloablative conditioning . We then evaluated the impact of selectable donor characteristics on survival while adjusting for the above variables. The results of this multivariate analysis are shown in Table P = 0.463, age >44 HR, 1.34; P = 0.134, Fig. n = 74) and as child vs. sibling for patients >40 years of age (n = 199). We further exam maternal donors vs. male donors and non-maternal female donors as well as maternal recipients vs. other female recipients and male recipients. There was no association with OS seen for any relationship category. HLA disparity and HLA DRB1 match status were not evaluated in the multivariate model as they did not reach significance in the univariate analysis.On univariate analysis (UVA), the following patient and disease related variables were found to be significantly associated with OS Table : patientP = 0.273, high/very high HR, 2.93; P = 0.005), disease in remission at transplant , and myeloablative conditioning . Controlling for these variables, the MVA , HCT-CI , and KPS . Subsequent MVA , but not in the multivariate model . There was no correlation between NRM and donor relationship or DRB1 status.Significant patient and disease-related variables in the UVA for NRM Table  consisteNo association was found between acute GVHD and any of the examined donor characteristics in the univariate analysis. This was true for both any grade aGVHD and grades III-IV aGVHD. Similarly, no association was seen for any donor characteristics and chronic GVHD or CRS. Thus, a subsequent MVA was not performed.Haplo HCT represents an important and increasingly utilized therapeutic option for patients undergoing allo-HCT. Patient, disease, and donor related characteristics all contribute to patient outcomes. While patient characteristics and disease biology remain largely unmodifiable, donor characteristics can often be selected for and optimized, especially in haplo HCT where many patients have multiple potential donors. This large, single center, retrospective study of patients receiving peripheral blood stem cell grafts examines the effect of a number of donor characteristics on outcomes, and demonstrates the importance of donor age in choosing the best haplo donor for the clinical situation.Somewhat surprisingly, our analysis revealed that increasing donor age was associated with higher NRM, but conversely reduced relapse risk. These opposing effects resulted in no net statistically significant difference in OS based on donor age. A trend toward improved overall survival was noted and it is possible that with a larger sample size this effect might reach significance. The deleterious effect of increasing donor age on NRM in haplo HCT has been demonstrated by others, including Canaani et al. and DeZern et al., who found the improvement in NRM with younger donors was such that it conferred a benefit in overall survival , 16. OurThe reduced risk of relapse with older donors is an unexpected and noteworthy finding of this analysis, though has been described in one other retrospective study by Mariotti et al. . A uniquA clear biological explanation for these observations has yet to be fully elucidated. One possible factor is the increased rate of clonal hematopoiesis of indeterminate potential (CHIP) among older donors. The recent work of Gibson et al. showed donor CHIP, specifically with DNMT3A mutation, was associated with reduced relapse . This coWe did not find that donor relationship had any effect on outcomes after controlling for donor age and patient variables - including age. Additionally, we were interested in the immunologic ramifications of non-inherited maternal antigens. Previously they have been associated with decreased rates of GVHD, and this increased tolerance could plausibly impact relapse and survival as well , 20. ThuWe wondered if the observed effects of donor age on NRM and relapse could be explained by correlation with another patient or disease characteristic known to be related to these outcomes, particularly the close association between donor and recipient age. However, in our analysis the correlation between donor and recipient age was modest (correlation coefficient=0.18) and each was able to be reliably assessed in the multivariate models. We carefully controlled for recipient age, donor-recipient relationship, sex, HCT-CI, DRI, disease status, conditioning regimen, CMV, and KPS and found that donor age remained a significant and independent predictor of NRM and Relapse. Additionally, NRM and relapse were evaluated using the Gray’s sub-distribution method to account for their competing risk. Our study has a number of limitations. While it benefits from uniformity in graft source, it is smaller than the multicenter and registry-based studies traditionally used for donor optimization. Furthermore, this is a single center, retrospective analysis. However, this did allow for granular data collection and uniform transplant protocols.In conclusion, increasing donor age was associated with higher NRM. However, relapse risk was lower with donors over the age of 30. These competing effects resulted in no significant difference in overall survival based on donor age. Our data suggests that in peripheral blood haplo-HCT, younger donors may be preferred in patients with high risk of transplant related complications. A unique finding of our analysis is the reduction in relapse we observed when using older donors. Further exploration of this effect is warranted in larger, multicenter studies, particularly in populations where relapse risk is high.Supplemental Figure 1Supplemental Figure 2Supplementary Figure Legends