目的 探讨不同方法测量扩散峰度成像(DKI)及体素内不相干运动(IVIM)模型DWI参数鉴别诊断乳腺良恶性肿块性病变的价值.方法 收集经病理或随访证实的59例乳腺肿块性病变患者(62个病变).MR检查包括动态增强MRI、IVIM DWI和DKI.分别于动态增强MRI强化最明显处设置ROI,测量其标准扩散系数(ADCstand)、慢速扩散系数(ADCslow)、平均峰度值(mean kurtosis,MK)和平均扩散系数(mean diffusion,MD);于病灶实性部分最大层面沿病变边缘勾画ROI,测量病灶整体的ADCstand-max、ADCslow-max、ADGfast-max、MK-max、MD-max,比较乳腺良恶性病变间各参数的差异,并绘制ROC曲线,比较AUC.结果 62个病变中,良性36个,恶性26个.良恶性病变间ADCstand、ADCstand-max、ADCslow、ADCslow-max、MK、MK-max、MD、MD-max差异均有统计学意义(P均＜0.001).ROC曲线结果显示ADCslow联合MK的AUC最大(0.915),诊断乳腺良恶性病变的敏感度和特异度分别为88.9％和84.6％.ADCstand与ADCstand-max(Z=1.465,P=0.143)、ADCslow与ADCslow-max(Z=1.013,P=0.311)、MK与MK-max(Z=1.021,P=0.307)、MD与MD-max(Z=1.428,P=0.153)间AUC差异均无统计学意义.结论 各DKI和IVIM DWI参数对鉴别乳腺良恶性肿块具有较高诊断价值,不同测量方法之间鉴别诊断效能无明显差异.

Objective To evaluate the value of IVIM-DWI and DTI parameters in quantitative analysis and differential diagnosis of invasive breast carcinoma of no special type(NST).Methods We retrospectively analyzed 60 patients (63 lesions)who underwent MR examination in our hospital and all lesions were verified by pathologic results.MR protocol included DCE-MRI,IVIM-DWI using 14b values and DTI.The ADC,ADCslow,ADCfast,f,λ1of lesions were measured and compared by two independent samples t test between the benign lesions and NST.Logistic regression analysis was made using ADC,ADCslow,f,λ1as predictors in detecting and differentiating the NST,ROC analysis was performed to compare diagnostic performance based on the area under the curve(AUC).Results The ADC,ADCslow,ADCfast,f andλ1of NST were (1.49±0.63)×10-3mm2/s,(1.32±0.49)×10-3mm2/s,(25.98±21.84)×10-3mm2/s,0.20±0.13 and (4.98±0.47)×10-3mm2/s,these values of benign lesions were (2.31±0.66)×10-3mm2/s,(2.24±0.65)×10-3mm2/s,(18.71± 12.26)×10-3mm2/s,0.33±0.15 and(5.59±0.59)×10-3mm2/s.All parameters except ADCfast(P=0.271)had significantly statistical differences (P<0.000 1)between NST and benign lesions.The regression model showed that ADCslowwas an independent predictor in NST’s detection.Conclusion The ADC,ADCslow,f andλ1is helpful for differentiation between NST and benign lesions.The regression model is most valuable in NST detection and ADCslowis the preferred index.

目的 探讨高分辨率MRI对腕管段正中神经及其伴行结构解剖变异的检测价值.资料与方法 连续对2015年8月-2017年5月共257只手腕的高分辨率MRI图像进行回顾性分析,观察正中神经在腕管近端及腕管内的影像学表现,记录正中神经的位置、正中神经及其伴行结构有无解剖变异及变异的种类.结果 在质子密度加权脂肪抑制序列上,共219例(85.2％)正中神经在腕管内及其远端呈高或稍高信号;38例(14.8％)在腕管内呈等信号,而腕管近端的正中神经则呈等信号.在T1WI序列上,腕管内外正中神经均呈等信号.解剖变异:①正中神经二分(含高位分叉)7例(2.7％);②正中神经裂24例(9.3％);③永存正中动脉16例(6.2％),永存正中静脉15例(5.8％);④正中神经变异伴永存正中动脉7例(2.7％)、伴永存正中静脉4例(1.6％),同时伴永存正中动、静脉3例(1.2％).正中神经及伴行血管的变异多发生于左侧腕管,神经变异组的年龄偏小,血管变异组男性偏多(P<0.05).结论 高分辨率MRI可以清晰显示腕管内正中神经及其伴行结构的解剖变异,识别这些变异有助于腕管综合征的正确诊断,并避免在腕管松解术或其他腕部手术中损伤正中神经及其伴行结构.

Objective:Investigate the value of CARE kV technique in computed tomography angiography (CTA)of lower extremity arteries.Methods:Seventy-eight consecutive patients who underwent lower extremity CTA were randomly divided into Group A (CARE-kV group)and Group B (kV value was determined according to body mass index),with 39 cases in each group.The imaging findings including CT values at each measure point,contrast to noise ratio (CNR),CT dose index volume (CTDIvol),dose length product (DLP),effective dose (ED),reconstructed image quality,the edge mor-phology of vascular and intravascular filling of contrast agent of the two groups were measured and analyzed.Results:The mean CT values at each measure point (430.02 HU vs 374.11HU,P =0.10),CNR (26.60±11.20 vs 29.86 ±9.95,P =0.13),subjective scores of images quality in VR (3.38±0.59 vs 3.31±0.61,P =0.58)and MIP (3.79 ±0.40 vs 3.62 ± 0.49,P =0.08)were not significantly different between the two groups (P >0.05 ).There were significant differences of CTDIvol (4.41±1.32 vs 6.19±3.19,P =0.02),DLP (533.59 ±185.66 vs 711.29 ±388.63,P =0.03)and ED (8.00 ± 2.76 vs 10.66±5.82,P =0.03).Conclusion:CARE kV technique could be used in the lower extremity CTA,which not only could reduce the radiation dose effectively,but also ensure the image quality.The selection of tube voltage could be more reasonable and intelligent.