Rapid Cartesian versus radial acquisition: comparison of two sequences for hepatobiliary phase MRI at 3 Tesla
Johannes Budjan1, Philipp Riffel1, Melissa Ong1, Stefan O Schoenberg1, Ulrike I Attenberger1, and Daniel Hausmann1

1Department of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Mannheim, Germany


In patients with breath-holding difficulties, breathing artifacts can result in dramatically reduced image quality during hepatobiliary phase imaging. Rapid Cartesian as well as radial acquisition techniques are approaches to minimize these artifacts. In 21 patients, both techniques were used and compared regarding image quality and lesion conspicuity. For most patients, a high flip angle Cartesian sequence with short breath-hold interval was feasible and resulted in superior overall image quality. Radial techniques proved to be a valuable option for the few patients who were unable to hold even short breath-hold intervals.


Hepatocyte-specific gadolinium based contrast agents (HSCA) can provide substantial information for the classification and differential diagnosis of focal liver lesions1. In clinical routine, breathing artifacts can impair image quality and thus decrease diagnostic confidence. In a previous study on dynamic arterial phase imaging we found that patients receiving HSCA particularly suffered from breath-holding difficulties, probably due to their overall reduced general condition2. In this context, sequences with radial read-out seem to be a possible solution, as the influence of motion (i.e. breathing) on image quality is far less compared to Cartesian approaches3. On the other hand, new techniques in parallel imaging allow highly accelerated acquisition, resulting in shorter breath-hold intervals4. The aim of this study was to evaluate these different approaches for the reduction of breathing artifacts in the hepatobiliary phase - a T1-weighted, volumetric-imaging-breath-hold-examination-(VIBE) sequence with radial k-space sampling (radialVIBE) and a highly accelerated Cartesian VIBE with Dixon fat suppression (CD-VIBE).


40 min after injection of the HSCA (0,025mmol/kg KG Primovist, Bayer HealthCare, Germany) radialVIBE (TE 1,7 ms; TR 4,2 ms; resolution 0,9x0,9x3 mm3; flip angle 12°; 3 min acquisition in free breathing) and CD-VIBE (TE 2,5 ms; TR 5,5 ms; 0,9x0,9x3 mm3; CAIPIRINHA acceleration with r=2x2, flip angle 30°; breath-hold 10 sec) were acquired in 21 patients (15 male, 68±9 years), who showed breath-holding difficulties during the dynamic arterial sequence. 2 blinded readers assessed image quality (image sharpness, noise, artifacts, homogeneity of fat saturation and overall image quality) as well as conspicuity of focal liver lesions for both radial- and CD-VIBE.


Overall image quality was rated good to excellent for both sequences, with CD-VIBE receiving statistically significantly better ratings (p=0,02). While radialVIBE received better results regarding image noise and artifacts (p=0.03), both sequences were rated equally regarding sharpness and homogeneity of fat saturation. Focal liver lesion (n=25) conspicuity was rated significantly better in CD-VIBE (p<0.01). In 3 patients, CD-VIBE was rated as non-diagnostic due to severe breathing artifacts. In contrast, radialVIBE was rated diagnostic in those patients.


The majority of patients with breath-holding difficulties in the dynamic arterial phase sequence were able to follow the substantially shorter breath-hold in the accelerated Cartesian sequence used for hepatobiliary phase imaging. The superior lesion conspicuity and overall image quality in the CD-VIBE sequence (likely attributable to the increased flip angle) made the CD-VIBE the preferable technique for most patients. However, some patients showed breath-holding difficulties despite the short breath-hold interval, resulting in non-diagnostic hepatobiliary phase images using CD-VIBE. radialVIBE however was able to generate diagnostic images in those patients, which – despite its inferior overall image quality – allowed a detection and differentiation of lesions that were not visible on CD-VIBE.


Both highly accelerated Cartesian as well as radial acquisition techniques provide good to excellent image quality in hepatobiliary phase MRI. In comparison, CD-VIBE offers better overall image quality and focal liver lesion conspicuity. However, radialVIBE is a valuable alternative in patients unable to hold even short breath-hold intervals.


No acknowledgement found.


1. Matos AP, Velloni F, Ramalho M, et al. Focal liver lesions: Practical magnetic resonance imaging approach. World J Hepatol. 2015;7(16):1987-2008. 2. Budjan J, Ong M, Riffel P, et al. CAIPIRINHA-Dixon-TWIST (CDT)-volume-interpolated breath-hold examination (VIBE) for dynamic liver imaging: comparison of gadoterate meglumine, gadobutrol and gadoxetic acid. Eur J Radiol. 2014;83(11):2007-12. 3. Reiner CS, Neville AM, Nazeer HK, et al. Contrast-enhanced free-breathing 3D T1-weighted gradient-echo sequence for hepatobiliary MRI in patients with breath-holding difficulties. Eur Radiol. 2013;23(11):3087-93. 4. Ogawa M, Kawai T, Kan H, et al. Shortened breath-hold contrast-enhanced MRI of the liver using a new parallel imaging technique, CAIPIRINHA (controlled aliasing in parallel imaging results in higher acceleration): a comparison with conventional GRAPPA technique. Abdom Imaging. 2015;40(8):3091-8.

Proc. Intl. Soc. Mag. Reson. Med. 24 (2016)