MRI VIBE序列评价肝脏局灶性病变的价值

目的:探讨MRI快速梯度回波的三维容积式插入法屏气检查(three-dimensional volumetric interpolated breath-hold examination,3D-VIBE)序列多期动态增强扫描评价肝脏局灶性病变的价值.方法:对128例疑肝脏局灶性病变的患者采用常规自旋回波(spin-echo,SE)T2W、2D GRE T1W平扫及3D-VIBE序列钆剂增强的多期增强扫描和2D GRE T1W钆剂增强扫描.所有病例均先行T2W和T1W平扫,再相继进行3D-VIBE增强多期(动脉早期、动脉晚期和门静脉期)扫描和2D GRE T1W平衡期增强扫描.经手术、病理或综合CT、US等多种影像学及实验室检查确诊的肝脏局灶性病变患者51例(90个病灶).分析51例(90个病灶)各序列的MR征象、VIBE资料重建后对病灶血管及肝血管解剖的显示,评价3D-VIBE和2D GRE T1W序列对不同大小病灶检测与定性的准确性及对病灶组织学起源诊断的准确性.结果:3D-VIBE多期动态增强扫描与常规2D GRE T1W增强扫描对病灶总的检测及定性能力分别为98.9% (89/90)、91.1% (82/90)和86.7% (78/90)、75.6% (68/90)(P＜0.05). 对肝细胞癌、肝转移瘤、肝血管瘤、肝囊肿诊断的符合率分别为92.9%(39/42)、90.4%(19/21)、80%(12/15)、100%(12/12)和78.6%(33/42)、81%(17/21)、53.3%(8/15)、83.3%(10/12) (P＜0.05). 3D-VIBE肝动脉期扫描有44例(86.3%)肝动脉显示良好,门静脉期有46例(90.2%)门脉期显示良好;肝细胞癌17个病灶可清晰显示供血动脉,14个病灶显示引流静脉;1例肝血管瘤显示供血动脉;1例肝转移瘤显示毗邻静脉.结论:MRI 3D-VIBE多期动态增强扫描无论在病灶的显示及定性诊断方面,还是在病灶供血动脉、引流静脉及肝血管解剖的显示上均较常规2D GRE T1W增强扫描具有更高的临床价值.

Diagnostic Value of a Volumetric Interpolated Breath-hold Examination MR Imaging Sequence in Evaluating Focal Hepatic Lesions

Objectives:To investigate the diagnostic value of a fast gradient-echo(GRE) three-dimensional isotropic volumetric interpolated breath-hold examination(3D-VIBE) MR sequence capable of Gadolinium(Gd) enhanced multi-phase acquisitions in evaluating focal liver lesions.Methods:Conventional spin-echo T2W,2D GRE T1W plain scan,Gd-enhanced 3D-VIBE multi-phase acquisitions,and Gd-enhanced 2D GRE T1W scanning were performed for 128 suspicious patients with focal liver lesions in clinic or for other imaging examination basis.Native T2W and 2D GRE T1W were performed first,then 3D-VIBE fast scanning at early arterial,late arterial and portal venous phases respectively,last followed by 2D GRE T1W scanning at the equilibrium phase.The final diagnosis for 51 patients with a total of 90 focal liver lesions was confirmed by either surgical,pathology or integrating clinical data,imaging and laboratory findings,and follow-up observations,which formed into the study group.Among of them,there were 25 cases of hepatocellular carcinoma(42 lesions),7 cases of neoplasm metastasis(21 lesions),12 cases of cavernous hemangioma(15 lesions) and 7 cases of simple cyst(12 lesions).The lesion appearances on 3D-VIBE and 2D GRE T1W sequence were carefully observed along with delineation of hepatic arterial and portal venous structures on VIBE sequence.The lesion detection rates and lesion characterization ability were compared among various MR sequences.The diagnostic accuracies of 3D-VIBE and 2D GRE T1W for the genetic tissue of lesions were calculated.Results:The diagnostic accuracies of 3D-VIBE and 2D GRE T1W for lesion detection and characterization were(98.9%)(8990),91.1%(8290) and 86.7%(7890),75.6%(6890), respectively.There were significant differences(P<(0.05)).The diagnostic coincidence rates of hepatocellular carcinoma,neoplasm metastasis,cavernous hemangioma and simple cyst were 92.9%(3942),90.4%(1921),80%(1215),100%(1212) and 78.6%(3342),81%(1721),53.3%(815),83.3%(1012)on 3D-VIBE and 2D GRE T1W sequences(P<0.05),respectively.Using the data generated from 3D-VIBE sequence,the hepatic arterial anatomy was well delineated in 44 patients(86.3),while the portal venous structures were clearly depicted in 46 cases(90.2).The feeding arteries of 17 lesions and the draining veins of 14 lesions of hepatocellular carcinoma were clearly displayed through MIP and MPR reconstruction techniques.Conclusions:The performance of 3D-VIBE is better than 2D GRE T1W not only in lesion detection and characterization for patients with focal liver lesions,but also in being able to provide more information about the details of lesion hemodynamics and hepatic vascular anatomy.