DWI中不同b值对肝脏小病灶诊断价值的探讨

Approach the diagnostic values of different b values in DWI for detecting small focuses in liver

目的通过选择DWI中的不同b值,探讨检出肝脏小病灶的价值。方法对27例肝脏小病灶患者(其中包括肝囊肿5例、肝血管瘤6例、肝癌8例、肝转移瘤8例)进行MRI平扫、动态增强扫描及不同b值的DWI(50s/mm2、200s/mm2、400s/mm2、600s/mm2、700s/mm2、1000s/mm2),比较不同b值发现病灶的能力。结果27病例共89个小病灶,b值为50s/mm2时,显示小病灶数89个,随着b值的增加,显示小病灶的个数依次减少,分别为78个、45个、38个、29个、20个,假阴性率明显增加;图像质量用好、中、略差、差分级,b值为50s/mm2时,图像质量最好,随着b值的增加,图像质量逐渐下降。结论低b值能更敏感地检测出肝内小病灶,是MR的有益补充。

Objective By selecting different diffusion coefficient （b value） in DWI,to approach the worth of detecting small focuses in live. Methods Twenty-seven patients whose small focuses （including five cases of hepatic cyst,6 cases of hepatic hemangioma,8 cases of liver cancer,8 cases of liver metastases） were all scaned by ordinary MR,dynamic contrast-enhanced and DWI which applied different b values （50 s / mm2 ,200 s / mm2,400 s / mm2,600 s / mm 2,700 s / mm2,1000 s / mm2 ）. The capacities of different b values were compared. Results Eighty-nine focuses were detected in 27 patients, when b value was 50 s / mm2, all focuses were detected.As b value increasing, the number of focuses detected obviously turned low to78, 45, 38, 29, 20 respectively; image quality was graded into 4 levers （good, satisfied, unsatisfied, bad）, when b value was 50 s / mm2, images were best. As the b value increasing, the image quality turn bad. Conclusion when b value is low,DWI can detect small focuees more sensitive .The DWI can be a useful complement for ordinary MRI.