New Imaging Strategies Using a Motion-Resistant Liver Sequence in Uncooperative Patients

Abstract

MR imaging has unique benefits for evaluating the liver because of its high-resolution capability and ability to permit detailed assessment of anatomic lesions. In uncooperative patients, motion artifacts can impair the image quality and lead to the loss of diagnostic information. In this setting, the recent advances in motion-resistant liver MR techniques, including faster imaging protocols (e.g., dual-echo magnetization-prepared rapid-acquisition gradient echo (MP-RAGE), view-sharing technique), the data under-sampling (e.g., gradient recalled echo (GRE) with controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA), single-shot echo-train spin-echo (SS-ETSE)), and motion-artifact minimization method (e.g., radial GRE with/without k-space-weighted image contrast (KWIC)), can provide consistent, artifact-free images with adequate image quality and can lead to promising diagnostic performance. Understanding of the different motion-resistant options allows radiologists to adopt the most appropriate technique for their clinical practice and thereby significantly improve patient care.

Feasibility of free-breathing dynamic contrast-enhanced MRI of the abdomen: a comparison between CAIPIRINHA-VIBE, Radial-VIBE with KWIC reconstruction and conventional VIBE

“…3 Recently, new motion-resistant sequences were proposed, including radial acquisition of VIBE (Radial-VIBE) and controlled aliasing in parallel imaging results in higher acceleration with VIBE (CAIPIRINHA-VIBE). 4 Radial-VIBE with k-space-weighted image contrast (KWIC) reconstruction (KWIC-Radial-VIBE) has been proposed for freebreathing DCE-MRI of the abdomen. 3,5 According to a recent study, KWIC-Radial-VIBE is insensitive to respiratory motion, enabling the acquisition of high-quality images for free-breathing examinations.…”

Comparison of Three, Motion-Resistant MR Sequences on Hepatobiliary Phase for Gadoxetic Acid (Gd-EOB-DTPA)-Enhanced MR Imaging of the Liver

“…The acquired k-space samplings are offset from the normal grid-like sampling by shifting the sampling positions of alternate rows with respect to the partition-encoding direction (7,9,10). This technique can save the acquisition time and the breathholding time more effectively than the generalized auto calibrating partially parallel acquisition (GRAPPA) technique (8)(9)(10)13).…”

“…The newly developed, parallel acceleration technique (3D gradient recalled echo [GRE], with controlled aliasing in parallel imaging, resulting in higher acceleration [CAIPIRINHA]), can save image acquisition time, by modifying the phase encoding sampling manner, which leads to reduced aliasing artifacts and provides better image quality, although patients cannot hold their breath long enough (7)(8)(9)(10). Therefore, this rapid imaging technique that reduces respiration artifacts, may propel patients with short breathing capacity, into routine clinical MR practice.…”

Free-Breathing Hepatobiliary Phase Gd-EOB-DTPA-Enhanced MR Imaging with Radial VIBE Sequence: Comparison with Conventional Cartesian VIBE Sequence

“…Therefore, in recent liver MR imaging, taking high quality hepatobiliary phase images is very important. However, motion artifacts such as respiratory motion, cardiac pulsation, and bowel peristalsis can degrade the image quality of abdominal MR examinations [6][7][8].…”

“…The breath-hold fat-saturated three-dimensional (3D) T1-weighted gradient echo sequence is usually selected for hepatobiliary phase Gd-EOB-DTPA-enhanced MR imaging because of its ability to image thin slices of the whole liver within a single acquisition and to reduce motion artifacts [6,[9][10][11]. However, in patients with a diminished breath-hold capacity, such as elderly, debilitated, or pediatric patients, motion artifacts degrade image quality and diagnosis can become difficult [12,13].…”