小视野扩散加权成像提高宫颈癌诊断价值

Reduced Field-of-View Diffusion-Weighted MRI Improving Diagnostic Value in Cervical Cancer

目的探讨b值=1000 s/mm^(2)的小视野扩散加权成像(r-FOV DWI)对宫颈癌的诊断价值。方法回顾性搜集28例宫颈癌和30例无宫颈癌患者的MRI资料。患者在治疗前均行常规视野扩散加权成像(f-FOV DWI)及r-FOV DWI扫描,由两名影像医师分别对两组DWI图像质量进行主观评价,测量并计算两种DWI图像的肿瘤对比度和正常组织对比度并采用Mann-Whitney U test进行比较。结果两名阅片者均认为r-FOV DWI获得更好的图像质量且差异具有统计学意义(P均<0.05)。r-FOV DWI肿瘤对比度、正常组织对比度更显著(P=0.024,P=0.004)。结论b值=1000 s/mm^(2)的r-FOV DWI为宫颈癌早期诊断及分期提供更准确的信息。

Objective To evaluate the diagnostic value of reduced field-of-view(r-FOV)DWI(b=1000 s/mm~2)in patients with cervical cancer.Methods Twenty-eight patients diagnosed with cervical cancer and thirty patients diagnosed without cervical cancer by pathology were retrospectively included.All pelvic MRI sequences included f-FOV DWI(b=1000 s/mm~2)and r-FOV DWI(b=1000 s/mm~2)before therapy.Two radiologists independently rated image quality for r-FOV DWI and f-FOV DWI regarding anatomic detail,lesion conspicuity(only for patients with cervical cancer),presence of artifacts,and overall image quality using a 4-point scale.The scores were compared using Wilcoxon signed-rank test.Interobserver agreement was evaluated by weighted Kappa statistics.The contrast of the tumour tissue(for patients with cervical cancer)and normal cervical tissue(for patients without cervical cancer)were calculated and compared using the Mann-Whitney U test.The maximum tumour diameters were measured from two DWI sequences and compared with those from the TWI.The distribution and concordance of the maximum lesion diameters were shown in a Bland-Altman plot.Results The anatomic detail,lesion conspicuity,presence of artifacts,and overall image quality scores were higher for the r-FOV DWI than for f-FOV DWI(P=0.001-0.031).The interobserver agreement was fair to excellent for anatomic detail,lesion conspicuity,presence of artifacts,and overall image quality(Kappa=0.478-0.931 at r-FOV DWI and Kappa=0.457-0.916 at f-FOV DWI).The contrast of cervical cancer was higher for the r-FOV DWI than for the f-FOV DWI sequences(0.50±0.14 vs 0.42±0.15,P=0.024).The contrast of normal tissue was also higher for the r-FOV DWI than for the f-FOV DWI(0.39±0.1 vs 0.33±0.08,P=0.004).There was no significant difference in mean tumor ADC value between the two DWI sequences[(826.1±78.4)mm~2/s at r-FOV DWI vs(849.5±106.3)mm~2/s at f-FOV DWI,P=0.085].The tumour diameters measured from the r-FOV DWI experienced less bias than those from the f-FOV DWI.Conclusion r-FOV DWI(b=1000 s/mm~2)is technically feasible to acquire and could shows better image quality in terms of anatomic detail and lesion conspicuity with fewer artifacts than f-FOV DWI of the female pelvis.This could help radiologists to better assess cervical cancer in detail.