肝脏Gd-DTPA快速动态增强MRI的临床应用──较小HCC与FNH的动态增强表现

Clinical Application of Rapid Dynamic Gd DTPA enhanced MR Imaging in Liver:Dynamic enhanced MRI Manifestations of Small HCC and FNH

目的：运用梯度回波（ＧＲＥ）的快速场回波（ＦＦＥ）技术，对２０例肝肿块进行Ｇｄ－ＤＴＰＡ动态增强，旨在探明不同肿块的增强规律，提高肝肿块的诊断和鉴别诊断能力。材料与方法：选取经过其他影像学检查未确诊的２０例肝肿块，作常规自旋回波（ＳＥ）平扫后作Ｇｄ－ＤＴＰＡＦＦＥ序列快速动态增强扫描，分别测量病灶信号强度（ＳＩｌｅｓｉｏｎ），灶周正常肝脏信号强度（ＳＩｌｉｖｓｒ），背景噪声信号强度和标准差（ＳＩｎｏｉｓｅｃ±ｓ），计算不同病变不同时相的肝－病灶对比噪声比（Ｃ／Ｎ），描出不同肿块（本文只评价其中手术病理证实的１３例肿块，包括肝细胞癌１０例，局灶性结节增生３例的时间－病灶Ｃ／Ｎ曲线。结果：ＨＣＣ与ＦＮＨ两者曲线较接近（包括强化峰值和升降坡度），但在增强早期，ＨＣＣ的Ｃ／Ｎ值高于ＦＮＨ，３分钟以后二者强化值均下降，且ＦＮＨ的Ｃ／Ｎ值大于０，ＨＣＣ的Ｃ／Ｎ值小于０，此差异可持续１５～２０分钟。结论：不同的肝肿块，动态增强后的时间－Ｃ／Ｎ曲线不同，对ＨＣＣ及ＦＮＨ而言，增强早期（１分钟以内）及３分钟以后曲线差异较大，最有助于鉴别诊断。动态增强ＭＲ成像可作为肝脏常规ＳＥ序列成像的一种有效的补充方法。

Objective: To determine the characteristics of dynamic Gd DTPA-enhanced of 13 cases liver lesions with fast field echo (FFE) technique of gradient echo (GRE) and improve the accuracy of diagnosis in liver lesions.Materials and Methods:20 cases single liver lesion, unconfirmed by other imaging, were performed with conventional spin echo (SE) and rapid dynamic Gd DTPA enhanced with FFE sequences. The signal intensity of normal liver (SI liver), lesions (SI lesion) and noise in the image background (SI noise±[WT5”BX〗s[WT5”BZ〗) were measured respectively. The contrast to noise ratio of livers and lesions (C/N) were calculated in different phases of various liver lesion. 13 cases of single liver lesion were confirmed by histology or surgery, including 10 cases of hepatic cell carcinoma (HCC), 3 cases of focal nodular hyperplasia (FNH). According to the liver lesion C/N values of different lesions in each phase, the time C/N curves wre illustrated.Results:The time C/N curve of HCC is similar to that of FNH (including enhancement peaks, rising and dropping slope), but at early stage (within 1 minute) the C/N values of HCCs are higher, the second later stage (after 3 minutes) the enhancement value of them drops, the C/N valuse of FHNs is above zero, that of HCCs are below zero. These difference could last 15～20 minutes.Conclusion: Underwent rapid dynamic enhancement, the time C/N curves of various hepatic lesion are different, particularly at the early stage and the second later stage. Rapid dynamic Gd DTPA enhanced MRI can be used as a effective supplement method of conventional SE sequence of liver.