Goshima Satoshi, Kanematsu Masayuki, Kondo Hiroshi, Yokoyama Ryujiro, Kajita Kimihiro, Tsuge Yusuke, Watanabe Haruo, Shiratori Yoshimune, Onozuka Minoru, Moriyama Noriyuki
Department of Radiology, Gifu University School of Medicine, Gifu University Hospital, Gifu, Japan.
J Magn Reson Imaging. 2008 Sep;28(3):691-7. doi: 10.1002/jmri.21467.
To determine the optimal b values required for diffusion-weighted (DW) imaging of the liver in the detection and characterization of benign and malignant hepatic lesions.
MR images obtained in 76 patients including 28 malignant hepatic lesions (21 hepatocellular carcinomas and 7 metastases) and 27 benign lesions (12 hemangiomas and 15 cysts) were reviewed. DW-echo planner images (EPIs; b values with 100, 200, 400, and 800 s/mm2) were reviewed solely first, and then with T2-weighted EPIs (b=0 s/mm2).
Sensitivity for malignant lesions (74%) was highest on DW-EPIs with b value of 100 s/mm2 and T2-weighted EPIs combined (P<0.05), and sensitivity for benign lesions (87%) was highest on DW-EPIs with b value of 800 s/mm2 and T2-weighted EPIs (P<0.05). Specificities were comparably high for all sequences. The Az values for malignant lesions were 0.94, 0.90, 0.87, and 0.89, and those for benign lesions were 0.91, 0.89, 0.87, and 0.94 on DW-EPIs with b values of 100, 200, 400, and 800 and T2-weighted EPIs combined, respectively. Hepatic cysts were clearly distinguished with the cutoff ADC value of 2.5x10(-3) mm2/s using a b value of 400 s/mm2 or greater.
DW-EPIs with middle b values were not required in the detection and characterization of benign and malignant hepatic lesions.
确定在肝脏良恶性病变的检测与特征描述中，扩散加权（DW）成像所需的最佳b值。
回顾了76例患者的磁共振图像，其中包括28例恶性肝脏病变（21例肝细胞癌和7例转移瘤）以及27例良性病变（12例血管瘤和15例囊肿）。首先单独回顾DW回波平面成像（EPI；b值分别为100、200、400和800 s/mm²），然后再结合T2加权EPI（b = 0 s/mm²）进行回顾。
在b值为100 s/mm²的DW-EPI与T2加权EPI联合使用时，对恶性病变的敏感性最高（74%）（P < 0.05）；在b值为800 s/mm²的DW-EPI与T2加权EPI联合使用时，对良性病变的敏感性最高（87%）（P < 0.05）。所有序列的特异性都相对较高。在b值为100、200、400和800且与T2加权EPI联合使用的DW-EPI上，恶性病变的Az值分别为0.94、0.90、0.87和0.89，良性病变的Az值分别为0.91、0.89、0.87和0.94。使用b值为400 s/mm²或更高时，肝囊肿通过截断ADC值2.5×10⁻³ mm²/s可被清晰区分。
在肝脏良恶性病变的检测与特征描述中，不需要中间b值的DW-EPI。
