Nasu Katsuhiro, Kuroki Yoshifumi, Tsukamoto Tatsuaki, Nakajima Hiroto, Mori Kensaku, Minami Manabu
Department of Radiology, University of Tsukuba, Institute of Clinical Medicine, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8575, Japan.
AJR Am J Roentgenol. 2009 Aug;193(2):438-44. doi: 10.2214/AJR.08.1424.
The objective of our study was to determine the relationship between the signal intensity of hepatocellular carcinoma (HCC) assessed with diffusion-weighted imaging (DWI) and T2-weighted imaging and the apparent diffusion coefficient (ADC) with the histopathologic grade of each nodule.
MR examinations including DWI and T2-weighted imaging of 125 surgically resected hypervascular HCCs in 99 patients were retrospectively reviewed. Pathologic examinations revealed 25 well-, 61 moderately, and 39 poorly differentiated HCCs. Two radiologists reviewed the images and classified the signal intensity of each tumor on DWI and T2-weighted imaging by mutual agreement. The incidence of each signal intensity and the relationship between signal intensity and histopathologic grade were assessed for each sequence. The relationship between the ADC and histopathologic grade was also evaluated.
On DWI, 11 of 125 HCCs appeared hypo- to isointense, 27 tumors appeared slightly hyperintense, and the remaining 87 tumors appeared obviously hyperintense to the surrounding liver. Overall, 91.2% (114/125) of HCCs showed hyperintensity to the surrounding hepatic parenchyma. Statistical analysis showed that this rate on DWI was significantly higher than that on T2 turbo spin-echo (TSE) imaging (p < 0.001). On DWI, the tumors tended to show a brighter signal with rising histopathologic grade (p = 0.031), but this trend was not observed on T2-weighted imaging. ADC measurements revealed that the mean ADCs of well-, moderately, and poorly differentiated HCCs were approximately 1.45, 1.46, and 1.36 x 10(-3) mm(2)/s, respectively. There was no significant correlation between ADC and histopathologic grade.
The histopathologic grade of HCC had no correlation with the ADC, but HCC tumors tended to show a higher signal on DWI as the histopathologic grade rose. However, predicting the correct histopathologic grade of each HCC before surgery on the basis of DWI findings was difficult because of the large overlap among histopathologic grades.
本研究的目的是确定用扩散加权成像（DWI）和T2加权成像评估的肝细胞癌（HCC）的信号强度以及表观扩散系数（ADC）与每个结节的组织病理学分级之间的关系。
回顾性分析99例患者125个手术切除的富血管性HCC的MR检查，包括DWI和T2加权成像。病理检查显示25个高分化、61个中分化和39个低分化HCC。两名放射科医生对图像进行了复查，并通过相互协商对每个肿瘤在DWI和T2加权成像上的信号强度进行了分类。评估每个序列中每种信号强度的发生率以及信号强度与组织病理学分级之间的关系。还评估了ADC与组织病理学分级之间的关系。
在DWI上，125个HCC中有11个表现为低至等信号，27个肿瘤表现为轻度高信号，其余87个肿瘤表现为明显高于周围肝脏的高信号。总体而言，91.2%（114/125）的HCC表现为高于周围肝实质的高信号。统计分析表明，DWI上的这一比率显著高于T2快速自旋回波（TSE）成像（p < 0.001）。在DWI上，肿瘤倾向于随着组织病理学分级的升高而显示更亮的信号（p = 0.031），但在T2加权成像上未观察到这种趋势。ADC测量显示，高分化、中分化和低分化HCC的平均ADC分别约为1.45、1.46和1.36×10⁻³mm²/s。ADC与组织病理学分级之间无显著相关性。
HCC的组织病理学分级与ADC无相关性，但随着组织病理学分级升高，HCC肿瘤在DWI上倾向于显示更高的信号。然而，由于组织病理学分级之间存在较大重叠，基于DWI表现术前预测每个HCC的正确组织病理学分级很困难。
