Gadoxetic acid-enhanced high temporal-resolution hepatic arterial-phase imaging with view-sharing technique: Impact on the LI-RADS category

Effectiveness of deep learning-based reconstruction for improvement of image quality and liver tumor detectability in the hepatobiliary phase of gadoxetic acid-enhanced magnetic resonance imaging

PURPOSE

To evaluate the effectiveness of deep learning-based reconstruction (DLR) in improving image quality and tumor detectability of isovoxel high-resolution breath-hold fat-suppressed T1-weighted imaging (HR-BH-FS-T1WI) in the hepatobiliary phase (HBP) of Gadoxetic acid-enhanced magnetic resonance imaging (Gd-EOB-MRI).

MATERIALS AND METHODS

This retrospective evaluated 42 patients with 98 liver tumors who underwent Gd-EOB-MRI between March 2023 and May 2023 using three techniques based on HBP imaging: isovoxel HR-BH-FS-T1WI reconstructed (1) with DLR (BH-DLR +) and (2) without DLR (BH-DLR -) and (3) HR-FS-T1WI scanned with a free-breathing technique using a navigator-echo-triggered technique and DLR (Navi-DLR +). The three techniques were qualitatively and quantitatively compared by the Friedman test and the Bonferroni post-hoc test. Tumor detectability was compared using the McNemar test.

RESULTS

BH-DLR + (3.85, average score of two radiologists) showed significantly better qualitative scores for image noise than BH-DLR - (2.84) and Navi-DLR + (3.37) (p < 0.0167), and Navi-DLR + showed significantly better scores than BH-DLR - (p < 0.0167). BH-DLR + (3.77) and BH-DLR - (3.77) showed significantly better qualitative scores for respiratory motion artifact than Navi-DLR + (2.75) (p < 0.0167), but there was no significant difference in scores between BH-DLR + and BH-DLR - (p > 0.0167). BH-DLR + (0.32) and Navi-DLR + (0.33) showed significantly higher lesion-to-nonlesion CR than BH-DLR - (0.29) (p < 0.0167), but there was no significant difference in lesion-to-nonlesion CR between BH-DLR + and Navi-DLR + (p > 0.0167). BH-DLR + (89.8%) showed significantly better tumor detectability than BH-DLR - (76.0%) and Navi-DLR + (77.6%) (p < 0.05).

CONCLUSION

The use of DLR for isovoxel HR-BH-FS-T1WI was effective in improving image quality and tumor detectability.

Improved Display of Hepatic Arterial Anatomy Using Differential Subsampling With Cartesian Ordering (DISCO) With Gadoxetic Acid-Enhanced MRI: Comparison With Single Arterial Phase MRI and Computed Tomographic Angiography

BACKGROUND

In clinical practice arterial anatomy evaluation is often determined using computed tomographic angiography (CTA); the effect of enhanced MRI has been neglected.

PURPOSE

To evaluate whether multiple arterial phase (MAP) images from patients who underwent differential subsampling with Cartesian ordering (DISCO) acquisition would improve the hepatic arterial display compared with single arterial phase (SAP) and CTA.

STUDY TYPE

A prospective, randomized trial.

SUBJECTS

In all, 130 patients (mean age, 55.81 ± 9.43 years; range, 35-78 years) including 89 men and 41 women.

FIELD STRENGTH/SEQUENCE

3.0T, DISCO, liver acquisition with volume acceleration-flexible (LAVA-Flex), CTA.

ASSESSMENT

A simple randomization was conducted and the study was subdivided into study part I (DISCO vs. SAP) and study part II (DISCO vs. CTA). Ten hepatic arterial segments were independently evaluated by three readers in the axial plane and the quality of hepatic arterial display was assessed using a four-point scale.

STATISTICAL TESTS

Kendall's W-test, χ2 test, Mann-Whitney U-test, and Kruskal-Wallis one-way analysis of variance (ANOVA) test.

RESULTS

Excellent interobserver agreement was obtained for hepatic arterial display (all Kendall's W values >0.80). For study part I, the mean arterial display scores for the common hepatic artery (CHA), proper hepatic artery (PHA), left hepatic artery (LHA), right hepatic artery (RHA), left gastric artery (LGA), and gastroduodenal artery (GDA) obtained with DISCO were higher than that obtained with SAP imaging (all P < 0.01). For study part II, comparable image quality for CHA (P = 0.798), PHA (P = 0.440), LHA (P = 0.211), RHA (P = 0.775) LGA (P = 0.468), and GDA (P = 0.801) was obtained with DISCO and CTA.

DATA CONCLUSION

The use of MAP acquisition with DISCO is superior to the use of SAP in hepatic arterial display and compares favorably with CTA; in the future, DISCO possibly can replace the latter ionization-related method to provide a more comprehensive evaluation of the liver arterial vessels.

LEVEL OF EVIDENCE

1 Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2020;51:1766-1776.

Gadoxetate acid disodium-enhanced MRI: Multiple arterial phases using differential sub-sampling with cartesian ordering (DISCO) may achieve more optimal late arterial phases than the single arterial phase imaging

BACKGROUND

To prospectively determine whether the use of a multiple arterial phase imaging (DISCO) improve the capturing rate of late arterial phase with less motion artifact than single arterial phase obtained with gadoxetate acid disodium.

MATERIALS AND METHODS

From 06/2017 to 10/2018, prospectively acquired data of 132 patients who underwent either single (n = 67) or multiple arterial phase (n = 65) gadoxetate acid-enhanced MR imaging were analyzed. Two readers independently assessed arterial phase timing and the degree of motion artifact using a five-point scale. The kappa test was used to determine the agreement between the two readers, χ2 or fisher exact test were used for the categorical variables and Student t-test or Mann-Whitney U test were used for the comparison of the motion artifacts.

RESULTS

Good to perfect inter-observer agreement was obtained for the arterial phase timing and degree of motion artifact (all kappa value >0.70). Optimal timing of arterial phase was observed in 95.4% (62/65) of multiple arterial phase compared with 73.1% (49/67) of single arterial phase (χ2 = 12.209, p < 0.001). Motion artifact score of the late arterial phase images measured using single arterial phase acquisition (3.22 ± 0.68) was significantly higher than the multiple arterial phase (2.42 ± 0.74) group (t = 5.921, p < 0.001). For the multiple arterial phase comparison, motion artifact score of the 2nd, 3rd and 4th phases were also significant reduced compared with 1st, 5th and 6th phases (all p < 0.05).

CONCLUSION

The use of multiple arterial phase acquisition with gadoxetate acid disodium can improve the capturing rate of well-timed late arterial phase with less motion artifact.

LI-RADS 2017: An update

The computed tomography / magnetic resonance imaging (CT/MRI) Liver Imaging Reporting & Data System (LI-RADS) is a standardized system for diagnostic imaging terminology, technique, interpretation, and reporting in patients with or at risk for developing hepatocellular carcinoma (HCC). Using diagnostic algorithms and tables, the system assigns to liver observations category codes reflecting the relative probability of HCC or other malignancies. This review article provides an overview of the 2017 version of CT/MRI LI-RADS with a focus on MRI. The main LI-RADS categories and their application will be described. Changes and updates introduced in this version of LI-RADS will be highlighted, including modifications to the diagnostic algorithm and to the optional application of ancillary features. Comparisons to other major diagnostic systems for HCC will be made, emphasizing key similarities, differences, strengths, and limitations. In addition, this review presents the new Treatment Response algorithm, while introducing the concepts of MRI nonviability and viability. Finally, planned future directions for LI-RADS will be outlined.

LEVEL OF EVIDENCE

5 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2018;47:1459-1474.

Simultaneous acquisition of MR angiography and diagnostic images of abdomen at view-sharing multiarterial phases and comparing the effect of two different contrast agents

BACKGROUND

Simultaneous acquisition of magnetic resonance angiography (MRA) and diagnostic images is challenging in contrast-enhanced upper abdominal MRI.

PURPOSE

To evaluate the image quality of MRA of the abdomen acquired simultaneously with diagnostic MR images, and to compare the contrast effect, conspicuity of aortic branches, and pancreatic lesions in MRA between gadobutrol and gadoterate meglumine.

STUDY TYPE

Prospective.

POPULATION

Eighty-eight patients with known and suspected upper abdominal disease.

FIELD STRENGTH/SEQUENCES

3T/4D-eTHRIVE (T₁ -weighted fat-suppressed 3D fast gradient echo) for multiarterial phase imaging.

ASSESSMENT

The artery-to-muscle signal intensity ratio (SIR), conspicuity of aortic branches on the axial, maximum intensity projection (MIP), and volume-rendered (VR) images, and conspicuity of focal pancreatic lesions were compared between gadobutrol and gadoterate meglumine. The diameters of aortic branches were measured on axial MRA and computed tomography angiography (CTA) images and then compared.

STATISTICAL TESTS

Quantitative and qualitative data were assessed with the Mann-Whitney U-test. The diameters of aortic branches between MRA and CTA were compared with a Spearman rank correlation test.

RESULTS

View-sharing multiarterial phase imaging was successfully performed in all patients. The SIRs of common hepatic artery (P = 0.0051) and left renal artery (RA) (P = 0.045), vascular conspicuities of right and left hepatic arteries (P = 0.010 and 0.030) and right and left RAs on axial (P = 0.0065 and 0.036), and that of gastroduodenal artery on MIP (P = 0.039) with gadobutrol were significantly higher than those with gadoterate meglumine. The conspicuity of focal pancreatic lesions were comparable between the gadobutrol and gadoterate meglumine (P = 0.73). The vascular diameters on MRA and CTA were strongly correlated in all aortic branches (r = 0.842-0.942, P < 0.0001).

DATA CONCLUSION

High-quality MRA of the abdomen was obtained simultaneously with the diagnostic MR images using view-sharing multiarterial phase imaging that also demonstrated comparable image quality between gadobutrol and gadoterate meglumine.

LEVEL OF EVIDENCE

2 Technical Efficacy Stage 1 J. Magn. Reson. Imaging 2017.