高b值计算化DWI在前列腺癌诊断中的应用价值

Value of computed high b-value DWI in diagnosis of prostate cancer

目的:评诂高b值计算化DWI(cDWI)在图像质量和前列腺癌诊断效能方面与传统高b值扫描获得DWI(aDWI)之间的差异。方法:回顾性分析56例前列腺特异性抗原(PSA)筛查异常患者的临床资料,将b值为0和_(800)s/mm^(2)的aDWI图像重建出b值为_(1500)s/mm^(2)的cDWI图像,测量aDWI_(800)、aDWI_(1500)和cDWI_(1500)图像的病灶对比度,并对3组图像5个方面的图像质量评分。由2位放射科医师以方案1(T_(2)WI+aDWI_(800)+ADC)、方案2(T_(2)WI+aDWI_(1500)+ADC)和方案3(T_(2)WI+cDWI_(1500)+ADC)对患者进行回顾性诊断,采用ROC曲线评价诊断效能。结果:3组图像中,cDWI_(1500)组图像对比度为0.39±0.12,明显高于aDWI_(800)组(0.18±0.10)和aDWI_(1500)组(0.22±0.11)(P<0.01),且cDWI_(1500)组5个方面的主观质量评分均高于aDWI_(1500)组,差异均有统计学意义(均P<0.01)。ROC曲线分析示,方案2和方案3的AUC显著高于方案1,且方案2和方案3间差异无统计学意义(P=0.149)。结论:高b值cDWI能明显提高前列腺癌病灶的对比度和整体图像质量,在不增加扫描时间的同时诊断效能与高b值aDWI相当,可作为高b值aDWI诊断前列腺癌的替代方法。

Objective:To evaluate the difference between computed high b-value DWI(cDWI)and acquired high b-value DWI(aDWI)in image quality and diagnostic accuracy in prostate cancer.Methods:A retrospective analysis of clinical data of 56 patients with abnormal prostate specific antigen(PSA)was conducted.The cDWI images with b value of_(1,500)s/mm^(2)were reconstructed from aDWI images with b value of 0 and_(800)s/mm^(2).The lesion contrast of aDWI_(800),aDWI_(1,500)and cDWI_(1,500)images was measured,and the image quality of three groups was scored in five aspects.Two radiologists retrospectively diagnosed all patients using three protocols,protocolⅠ(T_(2)WI+aDWI_(800)+ADC),protocolⅡ(T_(2)WI+aDWI_(1,500)+ADC)and protocolⅢ(T_(2)WI+cDWI_(1,500)+ADC).The diagnostic efficiencies were evaluated using ROC curves.Results:Among the images of three groups,the image contrast of cDWI_(1,500)group was 0.39±0.12,which was significantly higher than that of aDWI_(800)group(0.18±0.10)and aDWI_(1,500)group(0.22±0.11)(P<0.01).The subjective quality scores of five aspects in cDWI_(1,500)group were higher than those in aDWI_(1,500)group(all P<0.01).ROC curve analysis showed that the AUC of protocolⅡand protocolⅢwas significantly higher than that of protocolⅠ,while the difference between protocolⅡand protocolⅢwas not statistically significant(P=0.149).Conclusions:High b-value cDWI can significantly improve the contrast and overall image quality of prostate cancer lesions,while maintaining diagnostic efficiency comparable to high b-value aDWI without the increased scanning time.It can serve as a good alternative in the diagnosis of prostate cancer.