多序列MRI检查在胆系结石诊断中的应用价值

The clinical value of multiple sequence MRI in detecting gallstones

目的:探讨胆系结石MRI检出的适宜序列,评价MRI推测胆系结石类型的可行性。方法:回顾性分析临床诊断胆石症,且手术取出最大径>8 mm的胆囊或胆管结石的30例患者。术前行上腹部轴面三维脂肪抑制快速扰相梯度回波(3D-FSPGR-FS T_(1)WI)、脂肪抑制快速扰相梯度回波(FSPGR-FS T_(1)WI)、稳态采集快速成像(FIESTA)和脂肪抑制快速自旋回波(FSE-FS T2WI)序列扫描。30例患者中,胆色素石16例,胆固醇石14例。观察各序列结石的信号特点,测量信号强度,计算结石检出率。采用McNemar′s检验对各序列胆系结石的检出率差异进行组间比较。采用Mann-Whitney U检验比较胆色素石与胆固醇石各序列信号强度之间的差异。结果:3D-FSPGR-FS T_(1)WI和FIESTA序列对胆系结石的检出率分别为93.33%(28/30)和96.67%(29/30)。胆色素石在3D-FSPGR-FS T_(1)WI上表现特征性高信号,绝大部分胆固醇石在所有MRI序列中为均匀或混杂的低信号。3DFSPGR-FS T_(1)WI上,胆色素石的信号强度高于胆固醇石[146.3(42.12)vs.32.15(35.61),P<0.0001]。结论:3D-FSPGR-FS T_(1)WI和FIESTA序列对胆系结石的检出率高,3D-FSPGR-FS T_(1)WI有助于结石的分类。

Objective:To explore optimal MRI sequences in the detection and classification of gallstones,and evaluate the feasibility of MRI in predicting the types of gallstones.Methods:The MR imagings of 30 patients with gallstones confirmed by pathology were retrospectively analyzed.All included gallstones were larger than 8 mm and were classified into two subtypes,pigment and cholesterol.The 3D fast spoiled gradient-echo T_(1)-weighted imaging with fat saturation(3D-FSPGR-FS T_(1)WI),in-phase fast spoiled gradient-echo T_(1)-weighted imaging(FSPGR-FS T_(1)WI),fast imaging employing steady-state acquisition(FIESTA),and single-shot fast spin-echo T2-weighted imaging with fat saturation(FSE-FS T2WI)were further applied in epigastrium before operation.The signal characteristics of each sequence were observed,the signal intensity was measured,and the stone detection rate was calculated.The difference of the detection rate of biliary stones in each sequence were compared using McNemar′s test.The signal intensity of gallstones between different sequence of pigment and cholesterol were compared using Mann-Whitney U test.Results:Among 30 patients,there were 16 cases with pigment gallstone and 14 cases with cholesterol gallstone.The detection rate of gallstones was 93.33%(28/30)and 96.67%(29/30)on 3D-FSPGRFS T_(1)WI and FIESTA sequences,respectively.On 3D-FSPGR-FS T_(1)WI sequence,most pigment gallstones presented with high signal.Most of the cholesterol gallstone appeared as homogenous or mixed low signal on all MRI sequences.The corrected average signal intensity of pigment gallstones were statistically higher than cholesterol gallstone on 3D-FSPGR-FS T_(1)WI[146.3(42.12)vs.32.15(35.61),P<0.0001].Conclusion:3D-FSPGR-FS T_(1)WI and FIESTA sequences are sensitive to detect gallstones,especially 3D-FSPGR-FS T_(1)WI is helpful to classify the type of gallstones.