Impact of contrast transit time on late arterial phase timing in Gd-EOB-DTPA-enhanced MRI

To investigate the physiological factors affecting the timing of late arterial phase imaging in gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic acid-enhanced MRI (EOB-MRI), with a focus on contrast transit times.

This retrospective study included 122 patients who underwent EOB-MRI between April and September 2024. Contrast transit times from the right atrium to the left ventricle (RA-LV time) and to the celiac artery (RA-CeA time) were measured using real-time bolus-tracking images. Using vascular enhancement patterns, the late arterial phase timing was visually assessed and categorized as Early, Appropriate, or Delayed. Differences among the imaging timing groups were analyzed using analysis of variance (ANOVA) and post hoc Welch's t tests with Holm correction, with a significance threshold of p < 0.05.

Mean RA-LV times (mean ± SD, range) were 7.0 ± 1.1 s (5.0-9.0 s), 5.2 ± 0.9 s (4.0-8.0 s), and 4.7 ± 0.6 s (4.0-6.0 s) for the Early, Appropriate, and Delayed groups, respectively; significant differences were observed between Early vs. Appropriate (p < 0.001) and Appropriate vs. Delayed (p = 0.02). Correspondingly, RA-CeA times were 12.4 ± 2.0 s (10.0-15.0 s), 8.9 ± 1.8 s (5.0-14.0 s), and 7.7 ± 1.1 s (6.0-10.0 s), respectively, with significant differences between Early vs. Appropriate (p < 0.001) and Appropriate vs. Delayed (p = 0.001). Additionally, significant differences in sex and height were observed between the Early and Appropriate groups (p < 0.01). No other variables showed significant differences.

Contrast transit times significantly affect the appropriateness of late arterial phase imaging in EOB-MRI. Incorporating individualized transit time assessment alongside conventional bolus tracking may improve the consistency of late arterial phase acquisition and enhance the performance for diagnosing hepatic tumors.