3D-FS-FLASH序列在肝细胞癌MRI诊断中的应用价值

目的　评价MRI三维 ( 3D)FS FLASH序列诊断肝细胞癌的价值。方法　 2 0名患者 2 8枚病灶运用二维和三维序列行二次动态增强检查。观察各序列对病灶的显示能力 ,测量信号值 ,计算对比噪声比 (CNR)和增强指数 (EI)。并对三维资料运用多种方法重建。结果　 3D FS FLASH动态增强发现病灶 2 8枚 ,优于二维增强的 2 4枚 (P <0 .0 5 )。二维增强动脉期、T2WI和三维增强动脉期CNR高于二维和三维平扫及增强实质期 (P <0 .0 0 1)。三维序列中病灶的EI >二维序列病灶EI>三维序列肝实质EI >二维序列肝实质EI (P <0 .0 0 1)。经重建 ,5枚病灶可显示供血动脉 ,1枚显示引流静脉 ,1例静脉曲张避免了误诊为肿瘤。结论　 3D FS FLASH动态增强扫描不但诊断肝细胞癌优于 2D序列 ,还能提供更多有价值信息。

Value of 3D-FS-FLASH Sequence in Diagnosis of Hepatocellular Carcinoma in MRI

Objective To evaluate the value of three-dimensional (3D) FS-FLASH sequence in diagnosis of hepatocellular carcinoma (HCC) in MRI. Methods Twenty-eight foci of HCC in 20 patients were underwent twice MR examinations in two days. Two-dimensional (2D) T1WI, T2WI and 2D Gd-DTPA multiphase dynamic enhanced imagings were acquired in the first examination, and three-dimensional (3D) T1WI and 3D Gd-DTPA multiphase dynamic enhanced imagings were acquired in the second. The appearances of foci in all sequences were compared. Signal intensities of foci, normal hepatic parenchyma and background noise were measured for calculating contrast-noise ratio(CNR) and enhancement index(EI). Multiple planar reconstruction(MPR) and maximize intensity projection(MIP) were used to evaluate the 3D images. Results 17, 7, 24, 4 and 28 foci were displayed in T2WI,nonenhanced 2D-T1WI,2D enhanced images,nonenhanced 3D-T1WI and 3D enhanced images, respectively(P<0.05).CNRs(mean SD) were 3.65±4.85(T2WI), 0.36±2.37(nonenhanced 2D-T1WI), 4.55±3.24(2D arterial-phase), -0.71±2.53(2D liver-parenchyma-phase), -0.36±1.18(nonenhanced 3D-T1WI), 3.62±3.60(3D arterial-phase) and -1.43±2.35(3D liver-parenchyma-phase), and CNRs of T2WI, 2D arterial-phase and 3D arterial-phase were higher than those of nonenhanced 2D-T1WI, 2D liver-parenchyma-phase, nonenhanced 3D-T1WI and 3D liver-parenchyma-phase(P<0.001). EI of focus in 3D enhanced imagings was the highest(1.0931±0.5987), focus in 2D enhanced the second(0.5369±0.2938,P<0.001), hepatic parenchyma in 3D enhanced the third (0.3479±0.4319,P<0.001) and hepatic parenchyma in 2D enhanced the fourth (0.1724±0.1573,P<0.001).Supplying arteries of 5 foci and draining vein of one focus were displayed by MIP. And by MIP, a variciform vein was avoided from being misdiagnosed as a carcinous focus. Conclusion 3D-FS-FLASH multiphase dynamic enhanced scanning are not only better than 2D scanning in diagnosis of HCC, but also able to offer much more valuable information.