Department of Gastroenterology and Metabolism, Graduate School of Biomedical & Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan.
Research Center for Hepatology and Gastroenterology, Hiroshima University, Hiroshima, Japan.
Abdom Radiol (NY). 2021 May;46(5):2014-2024. doi: 10.1007/s00261-020-02907-7. Epub 2021 Jan 1.
The aim of this study was to clarify the usefulness of the apparent diffusion coefficient (ADC) value in the differential diagnosis of localized autoimmune pancreatitis (AIP) and pancreatic ductal adenocarcinoma (PDAC) and the evaluation of response to steroids.
This study retrospectively analyzed 40 patients with localized AIP and 71 patients with PDAC who underwent abdominal MRI with DWI (b = 0 and 1000 s/mm). Their ADC values at the lesion sites and five MRI findings useful for diagnosing AIP were evaluated. In addition, ADC values before and after steroid therapy were compared in 28 patients with localized AIP.
The median ADC value was significantly lower for localized AIP than for PDAC (1.057 × 10 vs 1.376 × 10 mm/s, P < 0.001). In the ROC curve analysis, the area under the curve was 0.957 and optimal cut-off value of ADC for differentiating localized AIP from PDAC was 1.188 × 10 mm/s. ADC value ≤ 1.188 × 10 mm/s showed the highest sensitivity and accuracy among the MRI findings (92.6% and 90.7%, respectively), and when combined with one or more other MRI findings, showed 96.3% specificity. The median ADC values before and after steroid therapy (mean 7.9 days) were 1.061 × 10 and 1.340 × 10 mm/s, respectively, and ADC values were significantly elevated after steroid induction (P < 0.001).
The measurement of ADC values was useful for the differential diagnosis of localized AIP and PDAC and for the early determination of the effect of steroid therapy.
本研究旨在阐明表观扩散系数（ADC）值在鉴别局灶性自身免疫性胰腺炎（AIP）和胰腺导管腺癌（PDAC）以及评估对类固醇反应中的作用。
本研究回顾性分析了 40 例局灶性 AIP 患者和 71 例 PDAC 患者的腹部 MRI 弥散加权成像（b 值=0 和 1000 s/mm）。评估了病变部位的 ADC 值和 5 种有助于诊断 AIP 的 MRI 表现。此外，比较了 28 例局灶性 AIP 患者类固醇治疗前后的 ADC 值。
局灶性 AIP 的 ADC 值明显低于 PDAC（1.057×10-3mm/s 比 1.376×10-3mm/s，P<0.001）。在 ROC 曲线分析中，曲线下面积为 0.957，区分局灶性 AIP 和 PDAC 的 ADC 值最佳截断值为 1.188×10-3mm/s。ADC 值≤1.188×10-3mm/s 在 MRI 表现中具有最高的敏感性和准确性（分别为 92.6%和 90.7%），当与一种或多种其他 MRI 表现联合时，特异性为 96.3%。类固醇治疗前后（平均 7.9 天）的 ADC 值中位数分别为 1.061×10-3mm/s 和 1.340×10-3mm/s，类固醇诱导后 ADC 值显著升高（P<0.001）。
ADC 值的测量对鉴别局灶性 AIP 和 PDAC 以及早期确定类固醇治疗效果有帮助。
