Namimoto T, Yamashita Y, Sumi S, Tang Y, Takahashi M
Department of Radiology, Kumamoto University School of Medicine, Japan.
Radiology. 1997 Sep;204(3):739-44. doi: 10.1148/radiology.204.3.9280252.
To evaluate diffusion-weighted echo-planar magnetic resonance (MR) imaging for improving the specificity of characterization of liver tumors.
Diffusion-weighted echo-planar imaging was performed with a 1.5-T whole-body imager with use of a body phased-array coil in 51 patients with 59 hepatic masses (41 malignant tumors, nine hemangiomas, and nine cysts). Apparent diffusion coefficient (ADC) values were obtained with two motion-probing gradients (b = 30 and 1,200 sec/mm2) during each of the breath-hold periods, and an ADC map was constructed. The T2 was derived from spin-echo echo-planar images with echo times of 47 and 99 msec.
The ADC value of malignant masses (1.04 x 10(-3) mm2/sec) was significantly lower (P < .01) than that of benign masses (hemangiomas [1.95 x 10(-3) mm2/sec] and cysts [3.05 x 10(-3) mm2/sec]), although the T2s showed considerable overlap. A small amount of overlap in ADC values occurred among malignant tumors, hemangiomas, and cysts. ADC values of two cystic masses from ovarian carcinomas were within the range of those of hemangiomas.
These preliminary results indicate that diffusion-weighted MR imaging can be useful in characterizing focal liver masses. With the exception of cystic metastatic tumors, the technique may be especially useful in tumors that appear markedly hyperintense on T2-weighted images due to a long T2.
评估扩散加权回波平面磁共振（MR）成像对提高肝脏肿瘤特征描述特异性的作用。
使用1.5-T全身成像仪及体部相控阵线圈，对51例患有59个肝脏肿块（41个恶性肿瘤、9个血管瘤和9个囊肿）的患者进行扩散加权回波平面成像。在每次屏气期间，利用两个运动探测梯度（b = 30和1200秒/平方毫米）获取表观扩散系数（ADC）值，并构建ADC图。T2值来自回波时间为47和99毫秒的自旋回波回波平面图像。
恶性肿块的ADC值（1.04×10⁻³平方毫米/秒）显著低于良性肿块（血管瘤[1.95×10⁻³平方毫米/秒]和囊肿[3.05×10⁻³平方毫米/秒]）（P <.01），尽管T2值有相当大的重叠。恶性肿瘤、血管瘤和囊肿之间的ADC值存在少量重叠。两个卵巢癌囊性肿块的ADC值在血管瘤的范围内。
这些初步结果表明，扩散加权MR成像可用于肝脏局灶性肿块的特征描述。除囊性转移瘤外，该技术对于在T2加权图像上因T2较长而表现为明显高信号的肿瘤可能特别有用。
