Hepatic cavernous hemangiomas : the relationship between speed of intratumoral enhancement during dynamic MRI and apparent diffusion coefficient on diffusion-weighted imaging

Abstract

Purpose: To investigate the relationships between the apparent diffusion coefficients (ADCs) on diffusion-weighted imaging (DWI) and the speed of contrast-enhancement during dynamic MRI of hepatic hemangiomas.Materials and Methods: Sixty-nine hepatic hemangiomas (≥1 cm) in 47 patients underwent DWI using multiple b factors (b=50, 400, 800 s/mm2) followed by gadolinium-enhanced dynamic MRI. The lesions were classified into three groups according to the intralesional filling-in of contrast material on the portal phase images (rapid, >75%; intermediate,25%-75%; slow, <25%). Besides the ADC measured on the ADC map, ADCs were manually calculated using two different b factors (mADC50-400 with b=50 and 400; mADC400-800 with b=400 and 800s/mm2).Results: Mean ADCs (x10-3 mm2/s) were significantly higher in the rapid group than in the intermediate (p=0.046) or slow groups (p=0.002). There were significant differences between the rapid and slow groups in mADC50-400 (2.12 vs. 1.48, p=0.008) and mADC400-800 (1.68 vs. 1.22, p=0.010) and between the rapid and intermediate groups in mADC50-400(2.12 vs. 1.79, p=0.049). Comparing mADC50-400 with mADC400-800, there was a significant difference only in the rapid group (p=0.001).Conclusion: Compared with slowly-enhancing hemangiomas, higher ADCs of rapidly-enhancing hemangiomas might be related to richer intralesional vascular perfusion.