MRI MOCO技术在肝脏局灶性病变诊断中的应用

Application of MOCO Technology in Diagnosis of Focal Liver Lesions

目的评估M R I运动校正(motio ncorrection,MOCO)技术对肝脏三维容积内插屏气扫描(three-dimensional volumetric interpolated breath-hold examination,3D-VIBE)动态增强图像的图像配准效果,探讨MOCO重建图像对提高肝脏局灶性病变检出率的作用。方法 52例怀疑有肝脏局灶性病变的患者进行MRI平扫和动态增强扫描。利用MOCO技术对增强扫描不同时相的3D-VIBE图像进行图像配准,得到MOCO重建图像。2位高年资腹部放射医师共同对肝脏平扫T1WI、T2WI、增强扫描不同时相的3D-VIBE图像和MOCO重建图像进行评判,以讨论结果作为最终意见。结果①52例受检者在3D-VIBE多期增强扫描中同一层位图像均出现不同程度的图像失配准,腹水及肝脏术后患者尤为明显。经过M O C O技术的校正,MOCO重建图像修正了因呼吸运动所致的多期扫描同一层位图像失配准;②对52例受检者的MR平扫、3D-VIBE和MOCO重建图像进行集体阅片,共同确认131个病灶。MOCO重建图像和3D-VIBE图像检出病灶数目分别为129个和116个,MOCO重建图像病灶发现率高于3D-VIBE图像(98.47%vs88.55%,x2=9.058,p=0.03)。MOCO重建图像对≤2.0cm的病灶的检出率高于3D-VIBE图像(83.52%vs97.80%),其差异有统计学意义(x2=10.965,P=0.001);③MOCO重建图像能更好显示FHL强化特征,能为FHL的诊断提供更真实的影像信息。结论 MOCO技术能修正由呼吸运动所致的多期扫描同一层位图像失配准,可以提高对小病灶的检出率,能更好显示FHL的强化特征,有助于FHL的影像诊断。

Objective To evaluate the effect of the motion correction （MOCO） technology in modifying the offset which caused by resipiratory motion in three- dimensional volumetric interpolated breath-hold examination （3D-VIBE） images of the dynamic contrast-enhanced liver MRI. To measure the diagnostic perfor- mance in the detection of local hepatic lesions （FHL） by using multiphase gado- linium-enhanced MOCO reconstructive images. Methods Fifty-two patients with suspected focal hepatic lesions （FHL） had been done the conventional MRI and 3D-VIBE multi-phasic dynamic contrast-enhanced liver MRI. The image registra- tion of 3D-VIBE images of the dynamic contrast-enhanced liver MRI was done by the MOCO technology. The final images analysis was adopt according to the consensus of two experienced abdominal radiologists. The images ofTl WI, T2W1, 3D-VIBE dynamic contrast-enhanced liver MRI and MOCO reconstructive im- ages were observed collectively. Results ① A significant mismatch of 3D-VIBE multi-phasic dynamic contrast-enhanced liver MRI data sets was observed in all cases especially in patients with ascites or after treatment. After MOCO technical correction, the same layer potential mismatch due to respiratory motion was corrected in MOCO reconstructed image in all cases. ② Conventional plane scan, 3D-VIBE multi-phasic acquisition and MOCO reconstructive images of 52 pa- tients were read in group. 131 lesions were confirmed commonly. 129 vs 116 foci lesions were displayed on MOCO reconstructive images and 3D-VIBE images respectively. Detection rate of FHL in MOCO reconstructive images was higher than that of 3D-VIBE images with statistically significant （98.47% vs 88.55%, x2=9.058, p=0.03）. The difference of lesion detection rate which size was less than 2.0cm between 3D-VIBE images and MOCO reconstructive images had statisti- cally significant （83.52% vs 97.80%, Z=0.438, p=0.048 ）. ③ MOCO reconstruc- tive image showed more enhanced features of the FHL than 3D-VIBE, which may lead to correct of the imaging diagnosis. Conclusion MOCO technology could correct the offset in 3D-VIBE multi-phasic dynamic contrast-enhanced liver MRI which caused by respiratory motion. It could improve the detection rate of small lesions and get more accurate information for FHL diagnosis.