View‐Sharing Artifact Reduction With Retrospective Compressed Sensing Reconstruction in the Context of Contrast‐Enhanced Liver MRI for Hepatocellular Carcinoma (HCC) Screening

Abstract

Background: View-sharing (VS) increases spatiotemporal resolution in dynamic contrast-enhanced (DCE) MRI by sharing high-frequency k-space data across temporal phases. This temporal sharing results in respiratory motion within any phase to propagate artifacts across all shared phases. Compressed sensing (CS) eliminates the need for VS by recovering missing k-space data from pseudorandom undersampling, reducing temporal blurring while maintaining spatial resolution. Purpose: To evaluate a CS reconstruction algorithm on undersampled DCE-MRI data for image quality and hepatocellular carcinoma (HCC) detection. Study Type: Retrospective. Subjects: Fifty consecutive patients undergoing MRI for HCC screening (29 males, 21 females, 52-72 years). Field Strength/Sequence: 3.0T MRI. Multiphase 3D-SPGR T 1 -weighted sequence undersampled in arterial phases with a complementary Poisson disc sampling pattern reconstructed with VS and CS algorithms. Assessment: VS and CS reconstructions evaluated by blinded assessments of image quality and anatomic delineation on Likert scales (1-4 and 1-5, respectively), and HCC detection by OPTN/UNOS criteria including a diagnostic confidence score (1-5). Blinded side-by-side reconstruction comparisons for lesion depiction and overall series preference (-3-3). Statistical Analysis: Two-tailed Wilcoxon signed rank tests for paired nonparametric analyses with Bonferroni-Holm multiple-comparison corrections. McNemar's test for differences in lesion detection frequency and transplantation eligibility. Results: CS compared with VS demonstrated significantly improved contrast (mean 3.6 vs. 2.9, P < 0.0001) and less motion artifact (mean 3.6 vs. 3.2, P = 0.006). CS compared with VS demonstrated significantly improved delineations of liver margin (mean 4.5 vs. 3.8, P = 0.0002), portal veins (mean 4.5 vs. 3.7, P < 0.0001), and hepatic veins (mean 4.6 vs. 3.5, P < 0.0001), but significantly decreased delineation of hepatic arteries (mean 3.2 vs. 3.7, P = 0.004). No significant differences were seen in the other assessments. Data Conclusion: Applying a CS reconstruction to data acquired for a VS reconstruction significantly reduces motion artifacts in a clinical DCE protocol for HCC screening. Level of Evidence: 3 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2019;49:984-993. View this article online at wileyonlinelibrary.com.

Multiarterial Phase Acquisition in Gadoxetic Acid–Enhanced Liver MRI for the Detection of Hypervascular Hepatocellular Carcinoma in High-Risk Patients

“…In contrast, sharing the peripheral k-space data of VS with the first acquisition subset with other image sets may share motion artifacts related to TSM. 31 Indeed, the incidence of TSM was 13.6% in CS-MAP, which falls into the reported frequency of TSM (10.7%-18%) in previous studies, 12,16,17,40 whereas the TSM incidence was 23.6% in VS-MAP. However, there was no significant difference in achieving optimal time for LAP between the CS and VS groups: failure to obtain optimally timed LAP images, regardless of TSM, occurred in only 4.9% (11/224) for CS-MAP and 5.6% (9/161) for VS-MAP.…”

“…The independent acquisition of k-space data at each AP of the CS technique increases the chance of obtaining AP image sets while avoiding the time of occurrence of TSM. In contrast, sharing the peripheral k-space data of VS with the first acquisition subset with other image sets may share motion artifacts related to TSM 31 . Indeed, the incidence of TSM was 13.6% in CS-MAP, which falls into the reported frequency of TSM (10.7%–18%) in previous studies, 12,16,17,40 whereas the TSM incidence was 23.6% in VS-MAP.…”

“…A higher score indicates better image quality, less artifact, higher SNR, less noise, more sharp liver edge, and less synthetic appearance (Table E1, http://links.lww.com/RLI/A740). 16,29,31…”

“…One potential limitation of VS techniques for MAP acquisition is that motion artifacts caused by respiratory motion during acquisition could propagate every AP image 30 . Shaikh et al 31 reported that applying a CS reconstruction for MAP images acquired by Differential Subsampling With Cartesian Ordering, which is a type of VS technique, after administration of gadobutrol, significantly reduces motion artifacts. Until now, there has been no study that has directly compared a VS-3D GRE technique and a CS-3D GRE technique for MAP imaging regarding image quality and focal liver observation detectability in patients at high risk for HCC.…”

Alternative approach of hepatocellular carcinoma surveillance: abbreviated MRI

“…Recent advances [64][65][66][67][68][69][70] that allow acquisition of multiple arterial phases in a single breath hold are finding their way into clinical practice, increasing the chances of capturing an optimally timed arterial phase, when HCC most commonly shows the highest degree of APHE [ Figure 6].…”