Callithrix jacchus), a commonly used small non-human primate, resembles humans in a variety of aspects. However, its cardiovascular system has not yet been sufficiently studied. It is imperative, though, to have a full understanding of this animal’s cardiovascular system and to have tools to accurately survey it. Therefore, for the first time, cardiac catheterizations along with intracardiac pressure–volume loop (PV loop) measurements were performed that provide real-time heart function data. By developing a protocol for cardiac catheterization (PV loop) in this animal species, the cardiac function in young, healthy animals was assessed. In the same animals, the obtained results were compared with generally established methods, namely, magnetic resonance imaging (MRI) and echocardiography. All three methods were suitable to describe cardiac function in the common marmoset; however, a comparison of the results revealed certain differences between the three techniques that are important for future research. Depending on the study objective, each method has its advantages and disadvantages and should, therefore, be carefully selected. The results provide the basis to establish the common marmoset as a promising primate model for cardiovascular disease.Animal models reflecting the human situation as accurately as possible are still essential to develop new therapies for diseases such as heart failure. The common marmoset  is an interesting candidate to investigate certain heart diseases and cardiovascular comorbidities, yet a basic functional characterization of its hemodynamic system is still missing. Therefore, cardiac functional analyses were performed by utilizing the invasive intracardiac pressure–volume loops (PV loop) system in seven animals, magnetic resonance imaging (MRI) in six animals, and echocardiography in five young adult male common marmosets. For a direct comparison between the three methods, only data from animals for which all three datasets could be acquired were selected. All three modalities were suitable for characterizing cardiac function, though with some systemic variations. In addition, vena cava occlusions were performed to investigate the load-independent parameters collected with the PV loop system, which allowed for a deeper analysis of the cardiac function and for a more sensitive detection of the alterations in a disease state, such as heart failure or certain cardiovascular comorbidities.Appropriate cardiovascular animal models are urgently needed to investigate genetic, molecular, and therapeutic approaches, yet the translation of results from the currently used species is difficult due to their genetic distance as well as their anatomical or physiological differences. Animal species that are closer to the human situation might help to bridge this translational gap. The common marmoset ( Cardiovascular diseases are the number one cause of death worldwide, with increasing incidence especially in the Western world . HyperteThe commonly used animal models for these research questions are typically rodent or porcine species. The possibility to generate genetically modified mice enables the basic clarification of genetic and molecular pathways, whereas—due to their size—larger animal models are often used to test new therapeutic interventional or surgical approaches ,5,6. HowCallithrix jacchus) is a small (300–500 g bodyweight), short-lived  are considered to mirror the human situation most closely and would—in theory—constitute the ideal animal model. The common marmoset , are a well-established and common technique for the comprehensive assessment of cardiovascular function in different animal models ,24,25,26Therefore, the aim of this study was to establish PV loop measurements in the common marmoset primates with potential application in future cardiac studies. In order to validate and classify the collected data, MRI and cardiac echography of the same animals were performed, and the results from the different methods were compared. To the best of the authors’ knowledge, admittance-based PV loop measurements have not been conducted in marmosets before. The provided surgery protocol as well as the reported results characterize the hemodynamic conditions of this interesting animal model and provide guidance and basic data, especially with regard to future cardiovascular investigations. The obtained outcomes contribute to the consolidation of the common marmoset in these fields of research.Animals were fostered and kept at the German Primate Center, Göttingen, Germany. Husbandry and experiments were conducted in compliance with Directive 2021/63/EU of the European Union and the German Animal Welfare Act and, therefore, met the regulations of the European Animal Research Association. The animal study protocol was approved by the institutional animal welfare committee and, subsequently, by the Lower Saxony State Office for Consumer Protection and Food Safety . Experimental procedures were in accordance with regulations of the German Legislature.2 cages or in family cages of 1 m2, 2.5 m height each, fulfilling the requirements of Directive 2021/63/EU of the European Union) either with a male or female partner animal or in a family group. Cages were equipped with one sleeping box per two animals, a hammock, branches, seat boards, wooden chips as litter on the ground, and weekly alternating enrichment such as swings and cartons. Temperature in the enclosures was kept constant at 26 ± 1 °C, with a relative humidity of 60–80% and 10 air changes per hour. Circadian rhythm was maintained at an alternating 12 h duration of light and dark. The diet was composed of a portion of porridge containing curd or milk mash and additional vitamins, minerals, and proteins in the morning. For lunch, animals were given a mixture consisting of fruit, vegetables, and pellets . The daily diet was variated by adding, for example, mealworms, gum arabic, nuts, seeds, and eggs. Water was offered in drinking bottles ad libitum. An enrichment protocol with, e.g., varying food and environmental enrichment, was implemented as part of the animal husbandry. Seven healthy test-naive male common marmosets  were included in this study. Animals were selected by the husbandry unit of the German Primate Center, Göttingen, Germany. Before incorporating the animals into the study, a clinical and hematological assessment was carried out to ensure their health status. The mean age of 32.83 ± 1.08 months at the beginning (MRI measurement) reflects a human age of approximately 25–30 years. At this time, animals weighed, on average, 435 g ± 11.55 g (SEM). For characterization of the animal cohort at the time of PV loop measurement, see Marmosets were conventionally housed in indoor steel cages , instead of barbiturate, to prevent crystalline deposits in the heart tissue. Major organs including the heart were excised during necropsy and used for further analyses unrelated to this study.No blinding was performed during MRIs, echocardiography, or PV loop measurements to ensure correct identification of the respective animals. Data were analyzed in a blinded manner.Induction of anesthesia was achieved by intramuscularly injecting alfaxalone  and diazepam . After placement of a 26G intravenous catheter  into the vena saphena or the caudal vein and intubation of the animals , anesthesia was maintained with 2% propofol  and remifentanil . Animals were mechanically ventilated . Isoflurane  in a mixture of oxygen (50%) and ambient air (50%) was only used additionally to support or increase the depth of anesthesia. The flow rate was set to 1.5–2 l/min. To protect eyes from drying out, eye ointment  was applied to the cornea. Vital parameters such as heart rate, peripheral oxygen saturation (pulse oximetry), respiration rate, ECG, and rectal temperature were continuously monitored during the measurement .Anesthetized animals were placed in a sphinx position see A. Ear ba2, acquisition bandwidth = 200 kHz, echo position = 33.33%, spatial resolution = 0.2 × 0.2 × 1.2 mm3, 2 × 2 in-plane interpolation, slice gap = 0.3 mm, 12 slices, and 200 repetitions, resulting in a total acquisition time of approximately 54 min  equipped with a 330 mT/m gradient system . For signal reception, a single-loop receive coil with elliptical shape and diameter of 38 mm × 35 mm  was used. The ventricular function was quantified, as previously described , using s min see B,C. AfteInitial anesthesia was achieved by intramuscularly injecting alfaxalone  and benzodiazepine  or midazolam ) into the quadriceps muscle. A 26G intravenous catheter  was inserted into the vena saphena or alternatively the tail vein. Eye ointment  was used to prevent eyes from drying out. Abdomen, thorax, and neck were shaved with small electronic clippers up to the junction line of the mandibular branches.For transthoracic echocardiography, a sonography system  and corresponding transducer  with ultrasound gel were used. Animals were secured with adhesive tape in supine position on a heated plate (38–39 °C) with integrated electrocardiogram electrodes see D. A tempSubsequently, after conducting the ultrasound, the animals were intubated  and repositioned on a surgery table. Electrocardiography electrodes were attached to shaved points on the outer site of both forearms and one thigh. Anesthesia was maintained with 2% propofol  and remifentanil  via continuous infusion  and supported by a pressure-controlled ventilation with 1.5–3% sevoflurane  in a mixture of 40% oxygen and 60% ambient air. Sevofluran doses were adjusted according to the depth of anesthesia, with a constant ventilation flow of 2 L/h and post end-expiratory pressure of 1–4 mmHg . Depth of anesthesia was assured by checking on reflexes such as corneal reflex and inter-toe reflex as well as continuously monitoring vital parameters such as heart rate, peripheral oxygen saturation (pulse oximetry), respiration rate, and rectal temperature . During the intervention, body temperature was maintained at a physiological level by using a flat infrared heating pad (38–39 °C) and an inflatable thermal blanket ; both: The 37 °C Company, The Surgical Company International B.V., AJ Amersfoort, The Netherlands). The animals were placed in supine position on a rubber mat with the heating pad underneath and the thermal blanket above it, with arms and legs stretched outwards and fixated with a gauze bandage, if necessary.Opening the thorax made it necessary to ligate the trachea to the non-cuffed tube beforehand to secure optimal ventilation. Therefore, after local anesthesia , a median ~3 cm incision of the skin via blunt dissection was performed directly above the trachea, starting shortly below the larynx. Small elastic retractors  were attached to create a clear view of the surgery field. After this step, local anesthesia  was applied to the muscle layer. Muscle and fat around the trachea were gently prepared aside without damaging the surrounding tissue. The trachea was then ligated to the non-cuffed tubus see G with noFor hemodynamic measurements, an abdominal approach was selected see H–J: the (a)Blood and heart muscle resistivity were determined for each animal using a calibration probe . For measuring blood resistivity, ~0.2 mL blood was drawn from the femoral vein just before the intervention and added to a 1.5 mL Eppendorf tube. The calibration probe was immediately introduced to the blood to acquire values for resistivity. For determination of the heart muscle resistivity, the calibration catheter was positioned directly on the heart surface avoiding coronary arteries, before inserting the cannula as described above. All readouts were directly saved into the ADV500 system.(b)The pressure–volume catheter was presoaked in body-warm saline in a 1 mL syringe on the level of the animal’s heart 20 min prior to the measurement to adjust to 37 °C fluid. After zeroing pressure offset, the catheter was inserted into the ventricle lumen.Before the pressure–volume measurement some preparation steps had to be performed:The catheter was positioned in the center of the left ventricle by confirmation of the correct shapes of the pressure–magnitude loops (magnitude versus pressure) and the phase signal. Followed by a baseline scan to determine Gb-ED and Gb-ES, the measurement was started, and absolute blood volume and pressure loops were collected. Sampling rate was set to 400/s, and smoothing or digital filtering (30–50 Hz) was applied to filter out interference from other equipment, if necessary. To acquire a set of loops without potential breathing artifacts, ventilation was switched off for some seconds.To measure load-independent parameters, vena cava occlusions were conducted by carefully lifting the placed thread for a few seconds, until appropriate pressure and volume reductions could be observed  were analyzed using LabChart 8 Pro software .Per animal, a section of 13–35 representative loops for baseline data and 9–14 representative loops for occlusion data, depending on heart frequency as well as loop quality and steadiness, were selected and analyzed. Calculation for stroke volume (SV), ejection fraction (EF), cardiac output (CO), and arterial elastance (Ea) were performed by using the following formula :Tau (isovolumic relaxation constant) was calculated by LabChart program using the Weiss method.2) were reported, as given in LabChartPro program.For analysis of the compliance and contractility parameters, generated by performing vena cava occlusions, equations, as given in LabChartPro program, were used to calculate the respective parameters. For end-systolic pressure–volume relationship (ESPVR), parameters were calculated with linear equations as well as quadratic equations; for end-diastolic pressure–volume relationship (EDPVR), linear and exponential fits were applied to gain a comprehensive overview of possible collectable values. Respective coefficients of determination  and pressure–volume area (PVA) were calculated by LabChartPro using linear equation models for both ESPVR and EDPVR. For preload recruitable stroke work (PRSW), the linear equation, as given in LabChartPro, was used.Statistical analysis was conducted using SigmaStat 4.0 . Graphs were plotted using GraphPad Prism 9.3.1 . Normal distribution of all parameters was confirmed using the Shapiro–Wilk and Kolmogorov–Smirnov tests. Descriptive statistics were applied. Quantitative values are stated as mean ± standard error of the mean (SEM).For comparison of the methods, HR, EDV, ESV, EF, SV, and CO were assessed with each method. Repeated-measurements ANOVA followed by Bonferroni adjustments were used to compare the parameters.p-values <0.05 and <0.01 were considered as significant and highly significant, respectively. p < 0.001 was defined as being highly significant.An overview of the PV loop data and the corresponding graphs is presented in 2) for ESPVR were, on average, 0.816 ± 0.069 for the linear fit and 0.857 ± 0.048 for the quadratic fit. For EDPVR, an r2 value of 0.867 ± 0.035 was calculated for the linear fit and 0.843 ± 0.039 for the exponential fit. The end-systolic elastance (Ees), derived from the linear equation for ESPVR, was 0.467 ± 0.095 mmHG/µL. The volume at a pressure of 100 mmHg (V100) was calculated to be 214 ± 55 µL, using the linear equation model. The constant of curvilinearity (a) amounted to −0.012 ± 0.004 for the quadratic fit of ESPVR. The constant determined by nonlinear least squares regression (b) was 1.634 ± 0.494. For EDPVR, the index of stiffness (dp/dV)—the slope of the EDPVR—was 0.027 ± 0.009 mmHG/µL for the linear fit and 0.013 ± 0.004 mmHG/µL for the exponential fit. The axis intercept of the linear equation for EDPVR amounted to −1.132 ± 1.189. The constant k2 was 0.793 ± 0.292 in the exponential curve. Preload recruitable stroke work (PRSW) was described by a linear fit model with a mean r2 of 0.945 ± 0.017. The slope of the PRSW, representing the relation of SW and ESV and serving as an index of contractile function, was, on average, 40 ± 5 mmHG. The axis intercept for PRSW was, on average, −1949 ± 506 mmHG. For myocardial energetics, the elastic potential energy (PE) was calculated with linear models for both ESPVR and EDPVR and amounted to 3112 ± 1181 mmHG∗µL. This resulted in a mean pressure–volume area (PVA) of 6217 ± 1689 mmHG∗µL  as well as from both linear and exponential equation models for the end-diastolic pressure–volume relationship (EDPVR) are presented also see . The meaalso see .Volumetric and functional parameters of the left ventricle were obtained by MRI (free breathing IntraGate Flash in the short-axis orientation with whole heart coverage). The HR  during the MRI exam widely varied among the animals. However, the assessed volumes only showed mild variations within the expected heart-size-dependent differences. In detail, the average values of the left ventricular mass (LVM), EDV, ESV, and SV were 1.21 ± 0.04 g, 956 ± 53 µL, 365 ± 15 µL, and 591± 46 µL, respectively. The resulting EF was, on average, 61 ± 2%. In addition, investigations of the right ventricular function were performed: right ventricular mass (RVM), right ventricular end-systolic volume (RV-ESV), right ventricular end-diastolic volume (RV-EDV), right ventricular stroke volume (RV-SV), and right ventricular ejection fraction (RV-EF) were measured and accounted for 0.57 ± 0.02 g, 356 ± 32 µL, 875 ± 45 µL, 518 ± 28 µL, and 59 ± 2%, respectively .The echocardiographic investigations of the left ventricle in long-axis view also allowed for measuring ESV, EDV, SV, HR, CO, and EF, as with MRI and PV loops. In addition, left ventricular internal diameter in systole (LV IDs) and in diastole (LV IDd) as well as fractional shortening (FS) could be measured. The speckle tracking method of the echocardiographic system also allowed for strain analyses of the left ventricle. Accordingly, time to peak and peak could be acquired for the longitudinal and radial velocity, longitudinal and radial displacement, longitudinal and radial strain, and longitudinal and radial strain rates. The values for these parameters are presented, from the midventricular anterior wall segment, in p > 0.05, Prior to PV loops, MRI measurements were conducted in all animals and, additionally, echocardiographic analyses were performed in five of the animals. Comparisons of the volumetric and functional parameters of the left ventricle obtained by MRI (free-breathing IntraGate Flash in the short-axis orientation), PV loops, and ultrasound for the same five animals are summarized in Given the increasing interest in the common marmoset as an in vivo model in various research areas ,8, a comThe use of NHPs like common marmosets raises some ethical concerns  and theyThe present study not only provides an anesthesia and surgery protocol for the acquisition of pressure–volume hemodynamic data but also reveals, for the first time, basic values from young male marmosets as references for future studies. The comparison to the established cardiovascular assessment methods, echocardiography and MRI, as well as the discussion of the respective advantages and disadvantages supports researchers in deciding which method to use for their specific scientific question.PV loop measurements are considered as the standard to comprehensively assess cardiac function in animal models due to their ability to measure highly sensitive alterations in left ventricular function . In geneAs a first-time description, the basic data of PV loop measurements for young, healthy male marmosets were provided. Since admittance-based PV loop studies had not been performed in this animal species before, any comparison to previous studies is complicated: the group of McLennon et al. calculated the cardiac parameters for common marmosets based on radionuclide angiography data during a feeding experiment 30 years ago . Their iTo the best of the authors’ knowledge, only one other study (performed by coauthors of the current manuscript) reports on the cardiac MRI values of common marmosets. Moussavi et al. investigated the cardiovascular aging process of this animal species via MRI and observed values similar to those presented here . The repFor the cardiovascular parameters, which could also be collected via echocardiography and MRI, similar values of HR, EDV, ESV, SV, and CO for PV loops and echocardiography were assessed, whereas the volume MRI data were significantly higher. However, although differences in absolute values could be observed, EF remained rather similar between the methods. Interestingly, although showing the biggest variations in absolute values, the coefficients of variations for MRI were often lower compared to those for echocardiography and PV loops (data not shown).The literature research on comparisons of different imaging methods resulted in a mixed picture: studies in larger animal species or humans report on higher volumes in MRI and either slightly lower or higher EFs compared to echocardiography . In contThe inconsistencies in the results could also be partially explained by the different time points for the respective measurement methods. Through the use of machine learning, artificial intelligence (AI) could help identify the sources of error that arise from the temporal differences in measurements. By analyzing the available data and accounting for temporal variations, AI could identify patterns that are consistent over time. In this way, AI possibly aids in the evaluation of the cardiac function assessments described above and, thus, may complement previously described applications in the prevention and diagnosis of heart failure .Not only the surgical approach can significantly influence the outcome of hemodynamic measurements. One important factor is the anesthetic regimen: for the least cardio-depressive effects, the induction of anesthesia was performed with alfaxalone and benzodiazepines, followed by a combination of propofol and remifentanil supplemented with sevoflurane for maintenance, to provide balanced anesthesia with simultaneous adequate analgesia. The comparable low pressures during PV loop measurements indicate good anesthetic depth, which was confirmed by the maintained good peripheral blood perfusion. However, studies for the optimization of the anesthesia protocol could benefit the outcomes of future PV loop measurements. In addition to the anesthetic regimen, factors like body temperature and hydration status are known to influence cardiac performance. Similar to other small animal species, the common marmoset is also susceptible to temperature loss and dehydration under anesthesia, especially when invasive procedures are performed . ConsideOf the seven initially planned animals for this study, one animal had to be excluded from the hemodynamic measurements due to severe fibrillations as soon as the PV loop catheter was inserted into the heart. This unusual observation might be due to an underlying susceptibility of individual animals to the electric field emitted by the catheter. However, this phenomenon should be confirmed in future investigations.In conclusion, it was shown that PV loop measurements can be reliably performed in the common marmoset, and they nicely complement standard routine cardiological measurements like ultrasound and MRI. PV loops offer the additional benefit of providing pressure–volume relationships and give indications about ventricular chamber mechanical properties like contractility and chamber compliance, ventricular arterial coupling, and myocardial energetics. In contrast, ultrasound and MRI enable the repeated assessment of basic cardiovascular parameters and, in the case of MRI, provide the possibility of also measuring perfusion kinetics. Whereas the different methods might result in differences for absolute values, all of them reliably provide functional parameters. In addition to already established cardiovascular diagnostic methods, the measurement of hemodynamic functional parameters via PV loops, therefore, represents a valuable tool for the comprehensive assessment of cardiovascular function and allows for the assessment of important information about the common marmoset’s cardiovascular system in health as well as under pathological conditions.In summary, it was shown that all three commonly used cardiovascular assessment techniques can be performed in the common marmoset, each with its own advantages and disadvantages: echocardiography and MRI offer, as non-invasive imaging techniques, the possibility to repeatedly assess the heart function over the course of a study. However, especially MRI measurements are time-consuming and require considerable technical efforts; although important parameters can be assessed, information about intra-cardiac pressures cannot be obtained. Especially in small animals, it can be challenging to precisely determine volumetric data due to small chamber sizes, turbulent blood flows, and short T2 relaxation times and valve movements and, therefore, requires a specialized MRI team and technical equipment. However, up to date, MRI measurements have been considered the gold standard to precisely and non-invasively detect cardiac volumes. Contrast-enhanced protocols allow for the assessment of myocardial infarction in the MRI setting, and MR spectroscopy enables the study of the cardiac metabolism.Echocardiography is commonly available and can be routinely used to assess parameters like the wall and chamber dimensions. It requires appropriate expertise with imaging modalities; otherwise, the acquired values may be variable. The possibility to perform deformation imaging in the form of myocardial shortening provides information on the contractility and regional wall motion. Echocardiographic and MRI volumetric measurements usually rely on volumetric assumptions, and volume calculations require post-processing.In contrast to MRIs and echocardiography, PV loop measurements allow for comprehensive measuring, mostly of load-independent parameters, in real time, including the unique possibility to assess the LV performance contractility, elastance, energetics, and efficiency—all important to adequately assess heart function, especially under pathological conditions. Importantly, one has to be careful that the catheters are properly calibrated to accurately assess the volumetric values.Overall, echocardiography and MRIs are useful for non-invasive serial measurements, with the appropriate expertise and technical equipment. Invasive PV loop-measurements, in contrast, allow for a more comprehensive estimation of cardiac function, with the advantage of assessing the parameters on a beat-to-beat basis.


Fabry disease (FD) is a genetic lysosomal storage disease with frequent cardiovascular involvement, whose presence is a major determinant of adverse clinical outcomes. As a potentially treatable cause of left ventricular hypertrophy (LVH) and heart failure with preserved ejection fraction, the early recognition of FD is crucial to initiate enzyme replacement therapy and improve long-term prognosis. Multimodality imaging plays a central role in the evaluation of patients with FD and helps in the differential diagnosis of other conditions presenting with LVH. In the present review, we explore the current applications of multimodality cardiac imaging, in particular echocardiography and cardiovascular magnetic resonance, in the diagnosis, prognostic assessment, and follow-up of patients with FD. GLA gene. The prevalence of FD in males is currently estimated at 1 in 3100 to 1 in 8500, significantly higher than previous estimates, which did not take into account recent newborn screening studies [Fabry disease (FD) is an inherited X-linked lysosomal storage disorder secondary to altered glycosphingolipid processing resulting from reduced or absent activity of the enzyme α-galactosidase A (aGAL), owing to a mutation in the The abnormal deposition of globotriasylceramide (Gb3) in the myocardium leads to left ventricular hypertrophy (LVH), diastolic dysfunction and eventually heart failure with preserved ejection fraction, conduction disturbances, atrial and ventricular arrhythmias leading to sudden cardiac death (SCD). Despite its relative rarity, the recognition of FD is necessary as one of the potentially reversible causes of LVH; however, FD remains underdiagnosed. The introduction of enzyme replacement therapy (ERT) has significantly changed the natural history of FD but also highlighted the need for early diagnosis to maximize its efficacy . MultimoThe deposition of Gb3 occurs in all cardiac cells and tissues, including myocytes, endothelial cells, fibroblasts, and conduction system cells, leading to systolic and diastolic dysfunction, conduction disturbances and arrhythmias. FD is not a simple storage cardiomyopathy, as experimental and clinical studies have shown that cardiac damage occurs secondary to Gb3 deposition, but inflammation and fibrosis also play a significant role, causing the biochemical and functional impairment of myocytes . A seminDepending on mutation type and residual enzyme activity, two clinical forms exist: a classic early-onset type with renal, cardiac and nervous system involvement manifesting in childhood and a late-onset variant presenting with single organ involvement . In women, according to the degree of skewed inactivation of the X chromosome, clinical manifestations are heterogeneous in terms of severity and organ involvement and usually appear a decade later than in men .The diagnosis of FD in males is often based on the demonstration of the reduced or absent activity of the aGAL enzyme; in females, genotype confirmation is needed as the activity of the aGAL enzyme can be quite variable.ECG changes classically associated with early-phase FD consist of bradycardia and a short PR interval . The re(1)In lead V1: a QRS complex with a right bundle branch block and an rSR’ morphology (FD) versus an rS complex with J point elevation in V1 (HCM);(2)In lead aVF : ST-segment depression and a negative T wave (FD) versus a pathological Q wave and a discordant T wave (QT discordance) in HCM;(3)A short PR interval (FD) versus a first-degree atrio-ventricular block (HCM);(4)In lead aVL: a high R wave (>1.1 mV) and a large QRS (FD) versus a normal R wave and a narrow QRS (HCM).In the setting of unexplained left ventricular hypertrophy diagnosed using echocardiography, a standard ECG can help to differentiate FD from hypertrophic cardiomyopathy (HCM) . PeculiaExtra-cardiac manifestations of FD include, among other things, angiokeratomas, neuropathic pain, cornea verticillata, hypohidrosis, transient ischemic attack or stroke, renal failure, and hearing loss. Such extra-cardiac red flags should prompt further evaluation for FD in patients with suggestive imaging findings. In association with clinical and imaging assessment, biomarkers like troponin and natriuretic peptides are important for staging FD cardiomyopathy.GLA mutations. The treatment with ERT is costly and requires lifelong twice-a-month infusions; however, the early initiation of therapy is advocated as the progression of the disease may compromise its effectiveness. Criteria for initiation of ERT in FD patients have been defined: in particular, LVH  without  fibrosis and/or cardiac rhythm disturbances constitute a class I recommendation. On the contrary, treatment should not be initiated in FD patients with advanced cardiac disease with extensive fibrosis if only the heart is affected, as treatment is believed to be ineffective [In patients with Fabry disease, the goals of treatment are to avoid the development of LVH and fibrosis and, if this has already occurred, to prevent further progression and possibly reduce morbidity and mortality . ERT witffective .Cardiac imaging has proved fundamental in each aspect of Fabry cardiomyopathy. Echocardiography offers several techniques for the evaluation of patients with FD, ranging from standard two-dimensional transthoracic echocardiography and conventional Doppler to tissue Doppler and speckle-tracking methods. CMR has gained a leading role in FD as it is the reference modality for wall thickness and chamber size assessment , regional and global function of the myocardium, or non-invasive tissue characterization in a wide spectrum of cardiomyopathies. CMR has also provided significant insights into the mechanisms that lead from Gb3 deposition to inflammation and fibrosis. Early recognition of FD in the context of unexplained LVH is crucial to initiate ERT and limit the progression of the disease. CMR can unveil subclinical myocardial involvement, help to non-invasively differentiate FD from other diseases manifesting with LVH, mainly HCM, and stage the progression of the disease. The role of cardiac imaging is of great importance, especially in patients with cardiac variant FD, as they may be lacking suggestive extra-cardiac involvement.Echocardiography is often the first imaging modality to be performed in suspected FD or to investigate otherwise unexplained ECG abnormalities, and it is also useful during the follow-up of affected patients. The hallmarks of FD are concentric LV remodeling or hypertrophy with the often-disproportionate hypertrophy of the papillary muscles; preserved systolic function, as measured by a left ventricular ejection fraction (LVEF) with an impaired myocardial strain; and right ventricular (RV) hypertrophy .LVH is not specific to FD; it is present in other more common conditions, and other patterns of hypertrophy have been described, such as asymmetrical septal or apical hypertrophy, or even outflow tract obstruction (as in HCM). LVH is more common in male patients with FD, increases with age, and is associated with symptoms . RV hypeGlobal longitudinal strain (GLS), a reliable marker of LV systolic function in a broad spectrum of cardiomyopathies, is an early marker of FD cardiomyopathy, potentially useful for identifying gene carriers before LVH becomes manifest ,18. In aDiastolic dysfunction is common among patients with LVH and is sometimes observed even before LVH develops. Reduced tissue Doppler velocities, higher E/e’ ratios, and shortened isovolumetric relaxation times are early markers of cardiac involvement ,24,25. AThe “binary sign”, defined as a hyperechogenic stripe in the LV myocardium adjacent to a relatively hypoechogenic region, once considered an almost pathognomonic sign of FD , has beeCMR allows us to precisely identify and quantify left and right ventricular hypertrophy, including papillary muscle hypertrophy, and assess its spatial distribution .CMR is more sensitive than echocardiography in detecting changes in LV mass ,32. LV mLGE, representing areas of replacement fibrosis, is present in about 50% of patients . The preA study by Niemann  found thT1 mapping, a quantitative technique used to derive pixel-by-pixel T1 relaxation times of the myocardium, is particularly useful in FD. Likely due to the intramyocardial deposition of sphingolipids, native T1 values are lower than expected in other cardiomyopathies presenting with LVH, where native T1 is normal or, more frequently, increased, except for iron overload cardiomyopathy. Low T1 values can also testify to LV involvement before hypertrophy and fibrosis appear, allowing for an early diagnosis of cardiac involvement ,39. Low Extracellular volume (ECV) is usually normal in FD except for areas with LGE, confirming that, at least in part, LVH is due to cell hypertrophy rather than extracellular matrix expansion .T2 mapping shows elevated T2 values, both globally and in areas with LGE; this finding has been described  as a pecAtrial function, expressed as an LA conduit strain and evaluated using feature tracking CMR, has been found to be already reduced in patients in the pre-hypertrophic phase, where only T1 mapping abnormalities were present . This prThe characteristic features of FD using echocardiography and CMR are summarized in GLA gene mutations, especially those causing late-onset cardiac variants, of around 1% [GLA mutation in 1.3% of the patients [A hypertrophic phenotype may develop as an adaptive response to different stimuli, and CMR is key in the differential diagnosis of other diseases presenting with LVH, such as amyloidosis, HCM, aortic stenosis and hypertensive cardiomyopathy, or even LV hypertrophy in athletes, although a degree of overlap exists between these different conditions. FD is regarded as a phenocopy of HCM and, indeed, timely diagnosis is often missed as some patients with FD are misdiagnosed as having HCM and excluded from disease-modifying treatments. Accordingly, screening studies conducted in patients with HCM have found a prevalence of round 1% ,47. Simipatients . These fHCM sometimes can manifest with concentric hypertrophy, but the degree of hypertrophy is usually greater than with FD; in HCM, LGE and impaired regional strain are typically present in the most hypertrophied segments. In a study of 40 patients with LVH divided into 2 groups (FD and HCM) and matched for the degree of LVH and age, the FD group had lower LVEF, more reduced regional longitudinal strain in the inferolateral wall of the LV, and more impaired RV-free wall longitudinal strain, and the pattern of hypertrophy was more often concentric . The finCMR-based studies showed that atrial remodeling, expressed as more pronounced LA dilatation and worse LA strain, is greater in HCM than in FD cardiomyopathy, with a good potential for distinguishing the two conditions . AnotherIn cardiac amyloidosis, instead, native T1 values and ECV are globally increased, and LGE is often present with a global subendocardial or transmural pattern. LGE is less helpful in aortic stenosis and hypertensive cardiomyopathy, but elevated T1 values coupled with a globally reduced longitudinal strain in AS and regionally at the level of the septum in hypertensive cardiomyopathy are valuable clues.Despite being a multi-system disease, FD can be regarded as a predominantly cardiac disease from a mortality perspective since most deaths are SCDs . As discThe prognostic role of LV-GLS has been confirmed in a study by Spinelli et al. , where aAs discussed above, RV hypertrophy is common in FD patients. Graziani et al. , in a stThe extent of hypertrophy, indeed, seems to be associated with outcomes. In a prospective study of 78 patients, a maximum LV wall thickness > 20 mm measured using echocardiography was found in all subjects with ventricular arrhythmias . Elevate2 increase in indexed LV mass was linked to an 8% increase in the risk of adverse outcomes. Although the contribution of papillary muscles and trabeculations to LV mass is disproportionately elevated in FD patients compared to controls [CMR, LVH and LGE have been found to be potent prognostic factors in FD. In a study  involvincontrols , it was controls .In a study mentioned previously , patientFrom tissue characterization, lower native T1 values were found to be associated with clinical worsening at 12 months’ follow-up in a group of patients with genetically confirmed FD and no evidence of LVH . ElevateMultimodality imaging can potentially assist the treating physician after the initiation of ERT. Although the evidence is derived from mostly retrospective observations, it seems that imaging features assessed by echocardiography or CMR are able to predict the extent of response to available treatments.Echocardiography is frequently used for the longitudinal monitoring of patients with FD after treatment initiation, ideally every 6 to 12 months. Numerous studies have been conducted on markers of LVH, such as LV mass and LV wall thickness, showing conflicting results, with some studies showing progression despite therapy  and otheOther studies have demonstrated improvement in diastolic function: a decrease in the E/e’ ratio and LV filling pressures  and an i2 in the treatment arm, while it was 12 g/m2 in the control arm [Randomized data show that LV mass was significantly reduced after 6 months of treatment with agalsidase alpha: the mean decrease in indexed LV mass was 6.4 g/mtrol arm . Anothertrol arm  demonstrLGE is probably the most potent predictor of response to ERT. Beer at al.  demonstrAn increase in native T1 relaxation time has also been observed in treated patients, potentially signaling a reduced accumulation of sphingolipids in the myocardium , while nFD is one of the genetic diseases for which treatment is available and potentially capable of improving prognosis. Multimodality imaging allows for a comprehensive evaluation of cardiac involvement and is fundamental when the disease is in the subclinical phase, for diagnosis, prognostic assessment, and the evaluation of response to available therapies. CMR is the imaging technique of choice due to its ability to characterize myocardial tissue and provide reproducible measurements of LV mass. Echocardiography with strain imaging efficiently complements CMR. Further, longitudinal studies are needed to prospectively validate the proposed prognostic markers of FD cardiomyopathy, to find reliable imaging findings to trigger the initiation of therapy, and to monitor its progression over time.


Pancreas T2* remained significantly associated with future arrhythmias after adjusting for any other univariate predictor . According to the receiver-operating characteristic curve analysis for arrhythmias, a pancreas T2* < 6.73 ms was the optimal cut-off value. In TDT, pancreatic iron levels had significant prognostic power for arrhythmias. Regular monitoring and the development of targeted interventions to manage pancreatic IO may help improve patient outcomes.We assessed the value of pancreatic T2* magnetic resonance imaging (MRI) for predicting cardiac events from a large prospective database of transfusion-dependent thalassemia (TDT) patients. We considered 813 TDT patients  enrolled in the Extension-Myocardial Iron Overload in Thalassemia Network. MRI was used to measure hepatic, pancreatic, and cardiac iron overload (IO), to assess biventricular function and atrial dimensions, and to detect replacement myocardial fibrosis. The mean follow-up was 50.51 ± 19.75 months. Cardiac complications were recorded in 21 (2.6%) patients: one with heart failure (HF) and 20 with arrhythmias. The single patient who developed HF had, at the baseline MRI, a reduced pancreas T2*. Out of the 20 recorded arrhythmias, 17 were supraventricular. Pancreatic T2* values were a significant predictor of future arrhythmia-related events (hazard ratio = 0.89;  Beta-thalassemia is a common hereditary blood disease that affects the production of the beta-globin chain, leading to ineffective erythropoiesis, chronic hemolysis, and anemia ,2. TransHowever, because the body lacks efficient mechanisms to eliminate excess iron ,7, a majIn recent years, with the widespread use of T2* cardiac magnetic resonance (CMR), it has become evident that arrhythmias in TDT patients are mostly of supraventricular origin and that MIO is less strongly associated with the development of arrhythmias compared to heart failure ,29,30. ATo our current knowledge, no study has evaluated the prognostic role of pancreatic iron in TDT patients. We postulated that the measurement of pancreatic iron burden may play a role in cardiovascular risk stratification and should therefore be taken into account to better tailor iron chelation to the needs of patients.The goal of this multicenter study was to determine the value of pancreatic T2* MRI for predicting cardiac events (heart failure and arrhythmias) from a large prospective database of TDT patients who started regular transfusions since early childhood.We considered 836 TDT patients . All patients were white, regularly transfused since early childhood to maintain pretransfusion hemoglobin > 9–10 g/dL, and chelated. The mean age at the start of regular transfusions was 18.01 ± 39.87 months, while the age at the start of chelation treatment was 4.94 ± 5.89 years.The patients performed their first T2* MRI for pancreatic iron overload assessment within the Extension-Myocardial Iron Overload in Thalassemia (E-MIOT) project between October 2015 and January 2022. The E-MIOT project is an Italian network composed of 66 thalassemia centers and 13 MRI sites where a homogeneous, standardized, and validated T2* MRI technique is adopted . All cenThe study complied with the Declaration of Helsinki and was approved by the institutional ethics committee. All patients provided written informed consent.All patients underwent MRI using conventional clinical 1.5 T scanners from three main vendors , equipped with a phased-array receiver surface coil.®, Version 2.0, Consiglio Nazionale delle Ricerche and Fondazione Toscana Gabriele Monasterio, Pisa, Italy, Year 2015). Three small regions of interest (ROIs) were manually delineated over the pancreatic head, body, and tail, encompassing parenchymal tissue and bypassing large blood vessels or ducts and regions with susceptibility artifacts caused by gastric or colic intraluminal gas [For the quantification of tissue iron levels, T2* multiecho gradient-echo sequences were acquired. Five or more axial slices, including the whole pancreas , a mid-tinal gas . The gloinal gas  and convinal gas . The LV inal gas , and theinal gas . The gloSteady-state free procession (SSFP) cine images were acquired in sequential 8-mm short-axis slices from the atrioventricular ring to the apex to assess biventricular size and function in a standard and reproducible way . Areas o®; Bayer Schering Pharma; Berlin, Germany) intravenous administration at the standard dose of 0.2 mmol/kg. LGE images were not acquired in patients presenting with a glomerular filtration rate < 30 mL/min/1.73 m2, refusing the contrast medium administration, or with less than 10 years of age. LGE was deemed to be present when observed in two different views [To determine the presence of focal/macroscopic myocardial fibrosis, late gadolinium enhancement (LGE) short-axis and vertical, horizontal, and oblique long-axis images were acquired 10–18 min after Gadobutrol  and MedCalc version 19.8  statistical packages.Continuous variables were described as mean ± standard deviation (SD). Categorical variables were expressed as frequencies and percentages. The normality of the distribution of the continuous variables was assessed using the Kolmogorov–Smirnov test.t-test. Levene’s test was employed to verify the homogeneity of variances (homoscedasticity). In cases where Levene’s test yielded a significance level of less than 0.05, indicating that homoscedasticity could not be assumed, the Welch statistic was used. The Wilcoxon signed-rank test was employed for continuous values that did not exhibit a normal distribution. χ2 testing was conducted for categorical variables.For continuous variables that followed a normal distribution, comparisons between two groups were conducted using an independent-samples Analysis of covariance (ANCOVA) models were used to assess how potential covariates influenced the differences between groups concerning clinical and MRI parameters. Covariates were integrated into the analysis if a variable showed a significant difference between the groups and an association with the assessed outcome. When necessary, outcomes were log-transformed to achieve normality in the residual distributions and to equalize the residual variance.Correlation analysis was conducted using Pearson’s or Spearman’s tests, where appropriate.The Cox proportional hazard model was employed to examine the association between the prognostic variables under consideration and the outcome. The results were reported as hazard ratios (HRs) with 95% confidence intervals (CI).Kaplan–Meier curves were generated by relating the development of an outcome over time to each significant prognosticator. The log-rank test was employed to compare different strata in Kaplan–Meier analyses.To identify the optimal pancreas T2* cut-off for distinguishing the presence of a specified outcome, the maximum sum of sensitivity and specificity was computed from receiver-operating characteristic (ROC) curve analysis.p < 0.05 was considered statistically significant.In all tests, a 2-tailed Twenty-three patients were excluded from this study due to the presence of a cardiac complication  at the baseline MRI.The baseline demographic, clinical, and MRI features of the 813 considered TDT patients are summarized in p < 0.0001).Patients were homogeneously distributed in terms of gender, and the mean age was 36.47 ± 10.71 years. Mean global pancreas T2* was 13.16 ± 10.49 ms, and global pancreas T2* was significantly lower in patients with diabetes than in those without diabetes  patients.All patients were naïve to pancreatic T2* MRI, while 671 (82.5%) of them had already undergone at least one MRI scan for the quantification of cardiac and hepatic iron levels. These patients had been previously enrolled in the MIOT project, which lasted from 2006 to 2015 .The mean follow-up time was 50.51 ± 19.75 months (median = 51.94 months). Cardiac complications were recorded in 21 (2.6%) patients: one with HF and 20 with arrhythmias.The single patient who developed heart failure (six months after the MRI) was a female with diabetes and a history of ischemic stroke. At the baseline MRI, she had a global heart T2* value of 47.50 ms and a reduced pancreas T2* (5.50 ms).Out of the 20 recorded arrhythmias, three were ventricular and 17 were supraventricular . The mean time from the MRI to an arrhythmia episode was 30.28 ± 20.53 months (range: 1–67 months).In light of the increased prevalence of arrhythmias, all analyses were conducted considering only this cardiac disease.p < 0.0001) and was therefore used as a covariate in the ANCOVA. The difference in global pancreas T2* values remained significant even after the adjustment for age (p = 0.043). Compared to patients who were arrhythmia-free, patients with arrhythmias had comparable biventricular function parameters and prevalence of replacement myocardial fibrosis at baseline, but they exhibited significantly higher atrial areas indexed by BSA. Biatrial areas were independent of age, so ANCOVA correction was not performed.Age exhibited a significant inverse correlation with global pancreas T2* values . The HR for previous arrhythmias predicting future arrhythmias was 14.78 .Thirteen (1.6%) patients had a prior and resolved history of arrhythmias, all supraventricular . Patients who developed arrhythmias during the FU had a more frequent positive history of past arrhythmias than patients who did not develop arrhythmias . The area under the curve was 0.71 (95% CI: 0.68–0.74)  .Global pancreas T2* values were dichotomized according to their median value (12.99 ms) and also according to the cut-off value found on ROC curve analysis.p = 0.019). p = 0.012).Patients with a global pancreas T2* below the median level had an increased risk of arrhythmias compared to those with a global pancreas T2* above the median . p = 0.001).When patients were dichotomized according to the optimal cut-off obtained from the ROC curve, the difference in the arrhythmia-free survival between the reduced and nonreduced pancreas T2* groups was slightly more pronounced  taking up circulating NTBI [Our data confirm that supraventricular arrhythmias are the most common type of arrhythmia that cannot be predicted by the iron levels in the left ventricle of the heart . Conversing NTBI . These cThe introduction of a T2* cut-off of 6.73 ms may help identify patients at high risk for arrhythmias. In these patients, developing targeted interventions to manage pancreatic iron overload may help prevent arrhythmias and improve patient outcomes. In this context, recent longitudinal studies demonstrated that the three iron chelators in monotherapy were equivalent in terms of reduction of pancreatic iron levels , emergedIn addition to pancreas T2* values, increased left atrial area index emerged as a significant MRI predictor of arrhythmias. Left atrium dilatation is recognized as an early feature of cardiac remodeling in TDT , where tBeyond the MRI, age and male sex emerged as significant predictors of arrhythmias. Aging itself is associated with changes in the shape and size of the heart chambers, in the cardiac mechanical and electrical system, and in the heart’s energy production and utilization ,62. ThesIn conclusion, in TDT patients who have received regular transfusions since early childhood, elevated pancreatic iron levels have significant prognostic significance for arrhythmias. Therefore, regular monitoring of pancreatic iron levels may improve stratification of arrhythmia risk, and the development of targeted interventions to manage pancreatic iron burden, such as intensification or modification of iron chelation therapy, may help prevent or minimize the associated complications and further improve the prognosis of TDT patients.


This study evaluates how far T2 mapping can identify arthroscopically confirmed pathologies in the long biceps tendon (LBT) and quantify the T2 values in healthy and pathological tendon substance. This study comprised eighteen patients experiencing serious shoulder discomfort, all of whom underwent magnetic resonance imaging, including T2 mapping sequences, followed by shoulder joint arthroscopy. Regions of interest were meticulously positioned on their respective T2 maps, capturing the sulcal portion of the LBT and allowing for the quantification of the average T2 values. Subsequent analyses included the calculation of diagnostic cut-off values, sensitivities, and specificities for the detection of tendon pathologies, and the calculation of inter-reader correlation coefficients (ICCs) involving two independent radiologists. The average T2 value for healthy subjects was measured at 23.3 ± 4.6 ms, while patients with tendinopathy displayed a markedly higher value, at 47.9 ± 7.8 ms. Of note, the maximum T2 value identified in healthy tendons (29.6 ms) proved to be lower than the minimal value measured in pathological tendons (33.8 ms), resulting in a sensitivity and specificity of 100%  across all cut-off values ranging from 29.6 to 33.8 ms. The ICCs were found to range from 0.93 to 0.99. In conclusion, T2 mapping is able to assess and quantify healthy LBTs and can distinguish them from tendon pathology. T2 mapping may provide information on the (ultra-)structural integrity of tendinous tissue, facilitating early diagnosis, prompt therapeutic intervention, and quantitative monitoring after conservative or surgical treatments of LBT. Shoulder pain is a common clinical issue and a known cause of disability, which can lead to significant functional impairment and thereby compromise the overall quality of patients’ lives ,2. PathoIn addition to clinical examination, imaging techniques, especially non-contrast magnetic resonance imaging (MRI), are central to the evaluation of the shoulder joint. While a variety of common shoulder pathologies can be detected via MRI with relatively high diagnostic accuracy, several studies have reported suboptimal diagnostic performance regarding pathologies of the LBT, which are usually visualized in more advanced stages of tendinopathy or rupture ,8,9,10. Functional MRI sequences, such as T2 or T2* mapping, have mainly been used for the evaluation of ultrastructural changes affecting the collagen network of articular cartilage and have been shown to detect and quantify early degenerative changes in various joints ,17,18. BThus, the purpose of this study was to investigate the ability of T2 mapping to detect arthroscopically proven pathologies of the long biceps tendon and to quantify the correlating T2 values for damaged and healthy tendons.Over a period of three months, this study enrolled 19 consecutive patients with shoulder pain who were referred to our radiology department for preoperative MRI assessments between September and November 2017. MRI and shoulder arthroscopy were indicated when the patient complained of significant shoulder pain, severe enough to interfere with activities of daily living, and for which conservative therapy, including physical therapy and analgesic medications, did not improve the overall pain level. In patients with negative MRI examination, the indication for exploratory shoulder arthroscopy was based on the combination of symptom severity, clinical examination, and ineffective conservative therapy. Patients with endoprosthetic joint replacement or osteosynthetic material at the proximal humerus, advanced osteoarthritis , a previous shoulder joint surgery, or an age of less than 18 years were excluded from the study. In addition, one patient was excluded who mistakenly underwent a routine MRI protocol without T2 mapping sequences, leaving 18 patients for inclusion in the study. The study was approved by the Institutional Review Board of Heidelberg University (S-081/2010) and was conducted in accordance with the Declaration of Helsinki. Written informed consent was obtained from all patients after they were informed of the nature of the examination.After enrollment, each participant underwent the index test, which included a T2 mapping MRI sequence at 3 Tesla. Subsequently, the reference examination, a shoulder arthroscopy, was performed within a maximum period of 6 days (mean: 4 days). Based on the arthroscopy findings, the study population was divided into two subgroups: “healthy subjects” and “patients with confirmed LBT pathology”. With respect to item 5 from the latest version of the STARD guidelines published by the EQUATOR network (Centre for Statistics in Medicine (CSM), NDORMS, University of Oxford, Oxford, UK) in 2015, this study can, therefore, be defined as a prospective observational study .Each participant underwent imaging with a 3-Tesla MRI system with a 70 cm wide gantry and an 18-channel imaging matrix . The examination was conducted in the supine position with the shoulder joints kept stabilized in external rotation to ensure that the joint was positioned as isocentrically as possible. A standard house-internal MRI protocol was used to morphologically assess the joint structures, including the proton density-weighted fat-saturated sequences as well as the T1- and T2-weighted sequences without fat saturation. For the acquisition of the oblique coronal views, the sequences were acquired perpendicular to the glenoid fossa, whereas the oblique sagittal sequences were aligned parallel to the glenoid articular surface. A manufacturer-supplied oblique coronal multiecho spin-echo T2 mapping sequence  was used as the primary sequence of interest. In this sequence, a pixel-by-pixel, monoexponential, non-negative least squares analysis was conducted to determine the T2 relaxation times from the T2 parameters. This analysis resulted in a color-coded T2 map, which could then be used for subsequent analysis.The MRI protocol used in this study represents our in-house standard protocol augmented by the T2 mapping study sequence, and is based on a previous study by our research group investigating the diagnostic performance of T2 mapping with respect to the detection of superior labral anterior to posterior (SLAP) lesions . For morA picture archiving and communication system  was used to evaluate the morphologic sequences by two independent radiologists with 19 (CR) and 6 (FW) years of experience in musculoskeletal MRI. Both gained experience in the MRI evaluation of the shoulder joint through several training courses as well as by participation in previous studies with functional and quantitative MRI imaging techniques for (fibro)cartilaginous structures. The parameters for slice selection, magnification, and windowing were set by both radiologists, and the ambient light was minimized during the reading sessions. To ensure objectivity, the patients’ names, clinical data, arthroscopy results, and ratings from the other reader were blinded for both radiologists. As all study participants were informed about the additional study sequence and their upcoming shoulder arthroscopy, they were not blinded.Proton density-weighted, fat-saturated sequences were utilized to classify the LBT as either normal or damaged. Focal or longitudinal changes in signal intensity, a significantly increased tendon diameter, marked fraying or contour irregularities, and partial or complete tears of tendon substance were defined as LBT tendinopathy. If none of these diagnostic features were present, the LBT was considered normal.First, an oblique coronally orientated proton-density-weighted fat-saturated sequence dissecting the bicipital groove was used to identify the LBT and decide upon the optimal position for the placement of the region of interest (ROI). The ROI was placed in the section in which the largest longitudinal diameter of the sulcal part of the LBT was depicted and no partial volume effect was present . To furtTwo experienced orthopedic surgeons performed shoulder arthroscopy on all patients. The operations were performed under general anesthesia with the patients seated at an angle of 30–90° above the horizontal plane and the head fixed in a headrest. During the arthroscopy, both the labroligamentous and cartilaginous joint structures were assessed. A standardized questionnaire was used to evaluate the intra-articular portion of the LBT, including its extension into the sulcal portion. If medically indicated, a ventral approach was made for surgical intervention. The diagnosis of LBT tendinopathy was defined by a marked fraying of the tendon substance or significant changes in the tendon diameter. Partial tears were defined as a disruption of a single or multiple tendon fibers, whereas complete tears were defined as a disruption of the entire thickness of the LBT. In terms of the statistical calculations, partial and complete tears were also considered tendinopathic changes.The analysis of the patient’s demographic data was carried out in a descriptive manner, while the analysis of the continuous variables was summarized as the mean values, median, and associated extrema. The frequency and percentage were calculated for the qualitative variables. For comparison of the patients’ ages between the groups with and without LBT tendinopathy, the Wilcoxon two-sample test was used.t-test. The p-values were presented as two-sided p-values, and the level of significance was set to 5%. To assess whether the T2 mapping values were normally distributed, the Shapiro–Wilk test was used.For analysis of the T2 mapping values of the sulcal part of the LBT, three measurements were performed by the two readers and repeated within a time interval of 7 days for calculation of the intra-rater agreement. Statistical analysis of the T2 imaging was carried out descriptively using summary statistics and interpreted exploratively. A comparison of the groups with and without lesions was performed using a two-sample We performed an analysis of the diagnostic performance of T2 mapping for tendinopathic changes in the LBT or LBT lesions and reported the estimates and exact 95% confidence intervals for the sensitivity, specificity, positive predictive values, and negative predictive values. As complete separation of the data occurred, no ROC curves were plotted for the accuracy assessment.www.cran.r-project.org, accessed on 10 May 2022) by a qualified statistician who was independent of the study.As the raters were viewed as a random selection of observers drawn from a larger pool of possible observers, the intraclass correlation coefficient (ICC) was utilized to assess both the inter- and intra-reader agreement. In order to gauge interrater reliability, we employed a two-way random-effect model considering the subject and rater as random effects to estimate the ICC and 95% confidence intervals, following the methodology outlined by Shrout and Fleiss . Data anA total of 12 (66.7%) out of the 18 patients included were male, and 6 (33.3%) were female. The mean patient age was 52.4 ± 14.72  years. On average, patients with LBT tendinopathy were slightly younger than the healthy subjects (46.3 ± 17.2 (range: 22–64) years vs 60.0 ± 5.0 (range: 52–67) years). Out of the eight patients with arthroscopically proven LBT tendinopathy, seven (87.5%) were male and only one (12.5%) was female. In n = 7; 87.5%), whereas one patient (12.5%) was diagnosed with a complete tear. Using the conventional morphological MRI sequence, all eight patients with arthroscopically proven tendinopathy were detected by both readers.A total of 10 persons (55.6%) had healthy long biceps tendons, whereas 8 patients (44.4%) showed tendinopathic changes. Out of the eight patients with pathologic long biceps tendons, the majority showed minor lesions or partial tears (p < 0.001). In the subgroup of healthy individuals, the maximum T2 value measured was 29.6 ms, which was found to be lower than the minimum T2 value recorded in patients with confirmed LBT tendinopathy (33.8 ms). This difference led to a complete separation of the T2 mapping values between the normal and pathological tendon substance, as depicted in In matching the arthroscopy results, eight LBT lesions were detected in the MRI, and no additional lesions were found intraoperatively. The mean T2 values show a significant difference between the patients with LBT tendinopathy, with 47.9 ± 7.8 ms, and the healthy subjects, with 23.3 ± 4.6 ms  showed a near-perfect inter-reader agreement of 0.99 : 0.98–1.00). The intra-reader agreement for the two respective readers was also almost perfect, with 0.93 (95% CI: 0.86–0.97) for reader 1 and 0.96 (95% CI: 0.97–0.99) for reader 2.Although pathologies of the long biceps tendon (LBT) are a well-known cause of shoulder pain, limited mobility, and associated impairments in daily living, common diagnostic tools have proven to be low in accuracy, particularly regarding the evaluation of early tendon damage. When detected by conventional MRI or MR arthrography, most LBT pathologies are visualized at more advanced stages of rupture or tendinopathy ,8,9. Desp < 0.001). Additionally, the maximum T2 value in healthy subjects (29.6 ms) was lower than the minimum T2 value in damaged tendons . Therefore, these two findings, resulting in sensitivities, specificities, and positive and negative predictive values of 100% for all cut-off values between 29.6 and 33.8 ms (95% CI: 63.1–100.0%), demonstrate the ability of T2 mapping to evaluate tendinous tissues and to distinguish between healthy and damaged tendons. A previous study by our working group focused on the T2 mapping of SLAP lesions in the glenoid labrum [Therefore, the aim of this study was to evaluate the ability of T2 mapping to identify and quantify pathologies of the LBT and to distinguish them from healthy tendons using arthroscopy as the gold standard. As one major finding, the mean T2 values showed a significant difference between the healthy subjects (23.3 ± 4.6 ms) and patients with LBT tendinopathy , with a resulting sensitivity of 91.2% and specificity of 92.3% [While T2 hyperintensities are well-known radiological correlates of tendon or cartilage damage using morphological MRI sequences, the novel aspect of T2 mapping lies in its ability to quantify the actual T2 relaxation times and thereby provide objectifiable measures. Thus, several areas of potential clinical use can be inferred. First, by providing cut-off values, quantification of the T2 relaxation times may help to increase diagnostic accuracy in the detection of tendon lesions. While the complete statistical separation between healthy and pathological tendon substance described in this study may be partially due to the small study population, future studies with larger sample sizes might show a gradual increase in T2 values with progressing degrees of degeneration and ascribe certain stages of degeneration to the associated levels of increased T2 relaxation times. In an analogy using area-under-the-curve calculations, Li et al. reported a diagnostic cut-off value of 49.5 ms for discriminating between healthy subjects and early stages of osteoarthritis in the articular cartilage of the knee  in our study could potentially contribute to statistical artifacts, which may have influenced these findings to some extent.As evidenced by the almost perfect intra- and inter-reader agreement observed in the T2 values between the healthy and damaged long biceps tendons, T2 mapping demonstrates potential for reliable clinical utilization. The intraclass correlation coefficients (ICCs) for intra-reader agreement ranged from 0.93 to 0.96 (95% CI 0.86–0.99), while inter-reader agreement reached ICCs of up to 0.99 (95% CI 0.98–1.00). In concordance with this, previous studies on T2 mapping of the glenohumeral joint in healthy subjects have shown comparable intraclass correlation coefficients (ICCs), with good to excellent agreement among investigators ,49. NeveOur study has some limitations. As a major limitation, the small sample size has to be mentioned, as it has important statistical implications. In studies investigating a small number of participants, extreme values can have a disproportionate impact on confidence interval (CI) calculations, resulting in wider ranges. For this study, the 95% CI for sensitivity and specificity ranged from 63.1% to 100%, indicating the potential effect of the small sample size on the precision of these measures. Furthermore, this study recruited patients from a specialized referral center, which makes it highly selective and prone to sampling errors. The higher prevalence of LBT lesions in this specific population may have led to improved test performance. Given these statistical limitations, the results may apply only to our specific study cohort, giving this study the characteristics of a pilot or preliminary study. To address this concern, further studies with larger sample sizes are necessary. These larger studies would also provide the opportunity to more accurately differentiate lesion severity and potentially identify different T2 values for the respective lesion grades.Another limitation to consider is the possibility of human error in the manual placement of regions of interest (ROIs), which can lead to variability and subjective judgments. Although all patients were positioned for MRI examination in the same way and a standardized slice orientation was used for ROI placement , the exaAdditionally, it is important to note that, to the best of our knowledge, this study represents the first systematic evaluation of T2 mapping specifically for the LBT. As a result, there are no suitable studies available for direct comparison of the quantified T2 relaxation times in this context. The few existing studies on the T2 mapping of tendinous structures have reported similar results, with T2 relaxation times around 30 ms for healthy supraspinatus tendons, for instance ,25. HoweFinally, it should be mentioned that the T2 values analyzed in this study and the resulting diagnostic parameters are representative only of a field strength of 3.0 Tesla. Some studies comparing cardiac and uterine T2 mapping sequences at 1.5 and 3.0 Tesla found significant field strength-dependent differences in the mean T2 values ,51. WhilT2 mapping effectively detects and quantifies long biceps tendon (LBT) pathologies, as evidenced by the significantly higher T2 values observed in arthroscopically confirmed tendinopathy compared to provenly healthy tendons. Additionally, the high diagnostic performance values and strong inter-rater reliability (ICC) among radiologists further support this finding. Thus, T2 mapping has the potential to provide valuable insights into the (ultra-)structural integrity of the tendinous collagen network and may, therefore, serve as a valuable tool for early diagnosis, facilitating the prompt initiation of therapy. Additionally, by providing objectifiable measures, it may enable longitudinal quantitative monitoring during conservative therapy or after surgical treatment.


Acute vertigo and dizziness are frequent presenting symptoms in patients in the emergency department. These symptoms, which can be subtle and transient, present diagnostic challenges because they can be caused by a broad range of conditions that cut across many specialties and organ systems. Previous work has emphasized the value of combining structured history taking and a targeted examination focusing on subtle oculomotor signs. In this review, we discuss various diagnostic bedside algorithms proposed for the acutely dizzy patient. We analyzed these different approaches by calculating their area-under-the-curve (ROC) characteristics and sensitivity/specificity. We found that the algorithms that incorporated structured history taking and the use of subtle oculomotor signs had the highest diagnostic accuracy. In fact, both the HINTS+ bedside exam and the STANDING algorithm can more accurately diagnose acute strokes than early (<24 to 48 h after symptom onset) MRI with diffusion-weighted imaging (DWI). An important caveat is that HINTS and STANDING require moderate training to achieve this accuracy. Therefore, for physicians who have not undergone adequate training, other approaches are needed. These other approaches  rely on vascular risk factors, clinical symptoms, and focal neurologic findings. While these other scores are easier for frontline providers to use, their diagnostic accuracy is far lower than HINTS+ or STANDING. Therefore, a focus on providing dedicated training in HINTS+ or STANDING techniques to frontline clinicians will be key to improving diagnostic accuracy and avoiding unnecessary brain imaging. A chief complaint of acute vertigo or dizziness is related to about 2.1 to 7.1% of all emergency department (ED) visits ,4, whichThis emphasizes the need to distinguish between dangerous central and benign, self-limited peripheral vestibular disorders to avoid misdiagnosis. Overall, roughly 9% of cerebrovascular events are missed at the initial ED presentation and risk of misdiagnosis is much greater when the presenting neurologic complaints are mild, nonspecific, or transient (range 24–60%) . For posApproximately 25% ± 15% of AVS patients will be diagnosed with a stroke, usually in the posterior circulation . The desEven MRIs including DWI in AVS have limited sensitivity, missing about one out of five vertebrobasilar strokes presenting as an AVS when obtained within the first 24–48 h after symptom onset . This faFortunately, the evidence base for effective bedside differentiation of inner ear diseases from stroke in patients with acute dizziness and vertigo has grown substantially over time ,18, as eTherefore, because of the limitations of current brain imaging techniques and because these various bedside evaluation tools have the potential to outperform imaging, we reviewed the diagnostic performance of these relatively new diagnostic algorithms for the diagnosis of patients with the AVS patient. We will discuss the advantages and limitations of these specific clinical tools. A broad range of clinical scores has been proposed to diagnose patients with AVS  can accurately identify central causes (mostly ischemic stroke) in AVS patients . The thrThis is evidenced by the recently published GRACE3 clinical guideline on acute vertigo and dizziness in the ED , which itrained non-subspecialists  demonstrated a high accuracy when using either the HINTS or the HINTS+ exam. Although the sensitivity of the HINTS exam was comparable amongst these two groups , the specificity of the HINTS exam was higher in the subspecialist group than in the non-subspecialist group , indicating potential differences in the interpretation of test results ) ) . Thus, Ho the ED . Both tho the ED . Likewiso the ED  and the o the ED  as descro the ED . All patIn the hands of neuro-otologists and trained ED physicians, HINTS(+) has been very successfully applied . Less exFor these reasons, assessing for gait and truncal instability (GTI) has been proposed as a substitute for the HINTS exam for ED physicians who have not received any training in performing HINTS . In an a2 = 0.17) was reported in a single study [In a recently published meta-analysis including ten studies reporting on GTI in acutely dizzy patients, pooled estimated sensitivity reached 69.7% (43.3–87.9%) and specificity was at 83.7% (52.1–96.0%) when considering GTI ratings of two or three as indicative of a central cause . When cole study . The invFocusing on grade 3 GTI, another recent meta-analysis found a sensitivity of 35.8% (5.2–66.5%) and a specificity of 99.2% (97.8–100.0%), emphasizing that the presence of grade 3 GTI is highly suggestive of a central cause , whereasImportantly, several limiting factors in GTI analysis need to be considered. First, the timing of GTI testing varied among studies. Whereas some studies applied truncal instability testing early in the clinical examination, others performed testing only after having the patient rest for at least 5–10 min. Secondly, severe nausea or motion intolerance may prevent adequate testing for grades 2 and 3 GTI . HoweverMissed or delayed diagnosis of posterior circulation stroke is an important and, unfortunately, a common problem ,44,45,46For the bedside clinical assessment of acutely dizzy patients meeting the diagnostic criteria of an acute vestibular syndrome, looking for subtle oculomotor signs is key to increasing diagnostic accuracy. This approach was initiated by the introduction of the HINTS examination in 2009, with growing popularity among specialists. With more than ten high-level-of-evidence studies reporting on unselected patient populations, the utility of the HINTS, when performed by trained examiners, is clear. Thus, it is not surprising that the GRACE-3 clinical guideline, created by emergency physicians strongly recommends performing the bedside HINTS to optimally manage ED patients with acute dizziness . We wanttrained emergency physicians, non-sub-specialists, and neuro-otology/neuro-ophthalmology subspecialists [Both the HINTS(+) exam and the STANDING algorithm are very good exclusion tests in the hands of cialists . Gerliercialists . It is nImportantly, both HINTS(+)  and STANw as 47% , and neaThe diagnostic work-up of the acutely dizzy patient remains challenging, and absent or inadequate training in performing and interpreting subtle oculomotor findings constitutes important limitations, especially in frontline providers. Most ED physicians are not yet familiar with a structured approach to the dizzy patient as, e.g., outlined in the TiTrATE approach and HINTS(+) or similar bedside algorithms ,37. While the introduction of quantitative (video oculography—VOG) HINTS to the ED seems promising, increasing the diagnostic accuracy beyond that of neuro-otology experts ,50, thisThere is tempered validation of the findings of Wang et al. , that thDisseminating knowledge about the management of the acutely dizzy patient to frontline providers and providing dedicated training in HINTS+ or STANDING techniques will remain key to improving diagnostic accuracy and avoiding unnecessary brain imaging.