Clinical Evaluation of Free Breathing Contrast Enhanced T1w MRI of the Liver using Pseudo Golden Angle Radial k Space Sampling.
PURPOSE Contrast enhanced T1 weighted MR imaging of the liver is typically acquired using breath hold techniques to reduce motion artifacts and to allow for optimal diagnostic image quality. Insufficient breath holds during MR data collection can cause severe reduction of image quality up to the point of being non diagnostic. The aim of this study was to evaluate the subjective and objective clinical image quality of a novel free breathing radial k space sampling MR technique. MATERIALS AND METHODS Consent for this study was given by the local IRB committee. 86 patients who underwent both breath hold (BH) and free breathing (FB) late phase contrast T1w FS FFE liver MRI using conventional BH Cartesian (Cartesian eTHRIVE) and FB "pseudo golden angle" radial k space sampling (Radial eTHRIVE) were included in this retrospective analysis. Subjective analysis comprised 5 point Likert scale ratings (1 very good; 5 non diagnostic) for "artifact impact" "anatomic sharpness" "vessel sharpness" "contrast impression" and "overall diagnostic quality" Relative signal intensities in different ROIs were compared between Cartesian eTHRIVE and Radial eTHRIVE. For statistical differences paired Wilcoxon test and paired t test have been performed (p 0.05) RESULTS The MR scan time was significantly longer for FB Radial eTHRIVE (2 min, 54 s) compared to BH Cartesian eTHRIVE (0 min 15 s) Cartesian eTHRIVE demonstrated a superior subjective contrast impression and objective measurements revealed an increased lesion to liver contrast for hypointense liver lesions (Hypo LTLC: 0.33 0.19 vs. 0.20 0.11; p 0.000) while no difference was observed for hyperintense liver lesions (Hyper LTLC) Subjective evaluation showed superior anatomic sharpness ratings by both readers for Radial eTHRIVE. Most importantly, in a subgroup analysis of patients who were unable to perform adequate breath holds, free breathing Radial eTHRIVE still demonstrated good subjective image quality. CONCLUSION Free breathing, radial k space sampling T1w MRI of the liver delivers high diagnostic image quality, especially in patients who are unable to adequately perform breath hold maneuvers. Thus, Radial eTHRIVE can be an important clinical alternative in patients with impaired respiration status. KEY POINTS Delayed phase contrast enhanced MRI of the liver can be robustly performed using a "pseudo golden angle" Radial eTHRIVE sequence. Free breathing Radial eTHRIVE yields good diagnostic image quality in case of a high artifact burden in breath hold Cartesian eTHRIVE and thus could be used as a "back up" for patients with impaired respiratory capacity. A lower lesion to liver contrast ratio is observed for hypointense liver lesions in free breathing Radial eTHRIVE sequence. CITATION FORMAT Hedderich DM, Weiss K, Spiro JE et al. Clinical Evaluation of Free Breathing Contrast Enhanced T1w MRI of the Liver using Pseudo Golden Angle Radial k Space Sampling. Fortschr Rontgenstr 2018; 190: 601 609.
RoFo Fortschritte auf dem Gebiete der Rontgenstrahlen und der Nuklearmedizin