Perfusion of hepatocellular carcinomas measured by diffusion‐derived vessel density biomarker: Higher hepatocellular carcinoma perfusion than earlier intravoxel incoherent motion reports

Abstract

AbstractDiffusion‐derived vessel density (DVDD) is a physiological surrogate of the area of microvessels per unit tissue area. DDVD is calculated according to DDVD(b0b2) = Sb0/ROIarea0 – Sb2/ROIarea2, where Sb0 and Sb2 refer to the liver signal when b is 0 or 2 s/mm2. Pathohistological studies and contrast‐enhanced CT/MRI data showed higher blood volume in hepatocellular carcinoma (HCC) relative to native liver tissue. With intravoxel incoherent motion (IVIM) imaging, most authors paradoxically reported a decreased perfusion fraction of HCC relative to the adjacent liver. This study applied DDVD to assess the perfusion of HCC. MRI was performed with a 3.0‐T magnet. Diffusion‐weighted images with b‐values of 0 and 2 s/mm2 were acquired in 72 HCC patients. Thirty‐two patients had microvascular invasion (MVI(+)) and 40 patients did not have microvascular invasion (MVI(−)). Fifty‐eight patients had Edmondson–Steiner grade I or II HCC, and 14 patients had Edmondson–Steiner grade III or IV HCC. DDVD measurement was conducted on the axial slice that showed the largest HCC size. DDVD(b0b2) T/L = HCC DDVD(b0b2)/liver DDVD(b0b2). DDVD(b0b2) T/L median (95% confidence interval) of all HCCs was 2.942 (2.419–3.522), of MVI(−) HCCs was 2.699 (2.030–3.522), of MVI(+) HCCs was 2.988 (2.423–3.990), of Edmondson–Steiner grade I/II HCCs was 2.873 (2.277–3.465), and of Edmondson–Steiner grade III/IV HCCs was 3.403 (2.008–4.485). DDVD(b0b2) T/L approximately agrees with contrast agent dynamically enhanced CT/MRI literature data, whereas it differs from earlier IVIM study results, where HCC perfusion fraction was paradoxically lower relative to native liver tissue. A weak trend was noted with MIV(+) HCCs had a higher DDVD(b0b2) T/L than that of MVI(−) HCCs, and a weak trend was noted with the poorly differentiated group of HCCs (Edmondson–Steiner grade III and IV) had a higher DDVD(b0b2) T/L than that of the better differentiated group of HCCs (Edmondson–Steiner grade I and II).