Enhancement of abdominal structures on MRI at 1.5 and 3 T: a retrospective intraindividual crossover comparison.

OBJECTIVE: To quantitatively compare the extent of enhancement of abdominal structures on MRI in an intraindividual fashion at 1.5 and 3 T.

METHODS: HIPAA-compliant, retrospective, longitudinal, intraindividual, crossover study, with waived informed consent, of consecutive individuals scanned at both 1.5 and 3 T closed-bore magnets using gadobenate dimeglumine during different phases of enhancement at tightly controlled arterial phase timing. Quantitative ROI measurements and qualitative sub-phase arterial phase assignments were independently performed by two radiologists. Qualitative discrepancies were resolved by a senior radiologist.

RESULTS: Final population included 60 patients [41 female and 19 male; age, 49.35 ± 18.31 years (range 16-81); weight, 78.88 ± 20.3 kg (range 44.5-136)]. Similar enhancement peak patterns were noted at both field strengths. Interobserver agreement of quantitative evaluations was substantial. Significantly higher amplitudes of enhancement peaks were noted for all abdominal solid organs during all phases at 3 T, except for the pancreas (p = 0.17-0.30). Significantly higher amplitudes of enhancement peaks of the abdominal aorta at 1.5 T were noted.

CONCLUSION: Similar peak patterns of enhancement for abdominal structures were observed at 1.5 and 3 T, with solid abdominal organs showing a higher percentage enhancement at 3 T, while unexpectedly higher aortic higher percentage enhancement was observed at 1.5 T.

KEY POINTS: • Similar enhancement peak patterns at both field strengths for studied abdominal structures. • Significantly higher percentage enhancement of most abdominal organs at 3 T. • Non-statistically significant trend of higher pancreatic percentage enhancement at 3 T. • Significantly lower abdominal aortic percentage enhancement at 3 T.