Department of Neuroscience Imaging and Clinical Sciences, University "G. d'Annunzio", Chieti, Italy.
Department of Neuroscience Imaging and Clinical Sciences, University "G. d'Annunzio", Chieti, Italy; ITAB Institute for Advanced Biomedical Technologies, "G. d'Annunzio" University, Chieti, Italy.
Curr Probl Diagn Radiol. 2020 Nov-Dec;49(6):392-397. doi: 10.1067/j.cpradiol.2019.06.002. Epub 2019 Jun 8.
To assess the added value of diffusion weighted imaging (DWI) with intermediate (500 s/mm) and high (1000 s/mm) b values when combined to conventional contrast-enhanced magnetic resonance imaging (MRI) in identifying peritoneal neoplastic involvement.
Twenty-four patients with peritoneal carcinomatosis from gastrointestinal or gynecological tumors were retrospectively evaluated. All patients underwent peritonectomy with hyperthermic intraoperative chemotherapy and 1.5 T MRI including DWI with 500 s/mm and 1000 s/mm b values within 1 month from surgery. Images were independently reviewed by 2 radiologists with different experience in abdominal MRI in 3 separate reading sessions, the first including conventional MR images alone (T2-weighted, T1-weighted pre- and post gadolinium injection), the second conventional MRI and DWI with a b value of 500 s/mm (b 500-DWI), and the third conventional MRI and DWI with a b value of 1000 s/mm (b 1000-DWI). Apparent diffusion coefficient maps were included in the DWI analyses. Peritoneal dissemination was assessed in 9 anatomical sites, including right and left subphrenic space, paracolic gutters, small bowel mesentery, greater omentum, gastric-bowel serosa, free peritoneal surfaces, rectosigmoid-colon mesentery, and pelvis. The presence or absence of peritoneal dissemination for each patient and for each site was scored using a 5-point confidence scale. Sensitivity, specificity, and area under the curve (AUC) for identifying per-site peritoneal implants were calculated for each reader at each reading session. Interobserver agreement was evaluated using kappa statistics.
For both readers, the sensitivity and AUC values resulting from combined interpretation of conventional MRI and DWI (both b500-DWI and b1000-DWI) were significantly higher than those of conventional MRI alone (P < 0.001). The added value of DWI was greater for the less experienced reader (sensitivity 0.55, specificity 0.73, AUC 0.64 on conventional MRI; sensitivity 0.75, specificity 0.72, AUC 0.74 on b500-DWI; sensitivity 0.87, specificity 0.72, AUC 0.80 on b1000-DWI) than for the more experienced reader (sensitivity 0.63, specificity 0.75, AUC 0.70 on conventional MRI; sensitivity 0.76, specificity 0.77, AUC 0.77 on b500-DWI; sensitivity 0.85, specificity 0.72, AUC 0.79 on b1000-DWI), although the differences between the 2 observers were not statistically significant. Interobserver agreement resulted to be fair (κ = 0.30) when dealing with conventional MRI alone. The addition of b500-DWI and b1000-DWI to conventional MRI allowed to reach a substantial agreement (κ = 0.75).
The combined interpretation of high b value DWI and conventional MRI provides increased sensitivity and diagnostic performance in detection of peritoneal carcinomatosis in oncologic patients.
评估在识别腹膜肿瘤累及方面，扩散加权成像（DWI）与常规对比增强磁共振成像（MRI）联合应用时，中等（500 s/mm）和高（1000 s/mm）b 值的附加价值。
回顾性分析 24 例胃肠道或妇科肿瘤腹膜转移患者。所有患者均接受腹膜切除术联合高热术中化疗，并于术后 1 个月内行 1.5 T MRI 检查，包括 500 s/mm 和 1000 s/mm b 值的 DWI。2 位具有不同腹部 MRI 经验的放射科医生分别在 3 次独立阅读中对图像进行评估，第 1 次包括常规 MRI 图像（T2 加权、钆增强前和后 T1 加权），第 2 次包括常规 MRI 和 b 值为 500 s/mm 的 DWI（b 500-DWI），第 3 次包括常规 MRI 和 b 值为 1000 s/mm 的 DWI（b 1000-DWI）。DWI 分析中包括表观扩散系数图。腹膜播散在 9 个解剖部位进行评估，包括右和左膈下间隙、结肠旁沟、小肠系膜、大网膜、胃-肠浆膜、游离腹膜表面、直肠乙状结肠-结肠系膜和骨盆。使用 5 分置信度评分评估每位患者和每个部位的腹膜播散情况。计算每位读者在每次阅读时识别各部位腹膜种植的灵敏度、特异性和曲线下面积（AUC）。使用kappa 统计评估观察者间的一致性。
对于两位读者，常规 MRI 与 DWI（b500-DWI 和 b1000-DWI）联合解读的灵敏度和 AUC 值均显著高于单独使用常规 MRI（P<0.001）。对于经验较少的读者，DWI 的附加价值更大（常规 MRI 上的灵敏度为 0.55、特异性为 0.73、AUC 为 0.64；b500-DWI 上的灵敏度为 0.75、特异性为 0.72、AUC 为 0.74；b1000-DWI 上的灵敏度为 0.87、特异性为 0.72、AUC 为 0.80），而对于经验丰富的读者则较小（常规 MRI 上的灵敏度为 0.63、特异性为 0.75、AUC 为 0.70；b500-DWI 上的灵敏度为 0.76、特异性为 0.77、AUC 为 0.77；b1000-DWI 上的灵敏度为 0.85、特异性为 0.72、AUC 为 0.79），尽管两位观察者之间的差异没有统计学意义。单独使用常规 MRI 时，观察者间的一致性为中等（κ=0.30）。将 b500-DWI 和 b1000-DWI 添加到常规 MRI 中可达到高度一致（κ=0.75）。
高 b 值 DWI 与常规 MRI 联合应用可提高肿瘤患者腹膜肿瘤累及的检出率和诊断效能。
