1 Department of Radiology, Soonchunhyang University College of Medicine, Bucheon Hospital, Bucheon, Republic of Korea.
2 Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Ilwon-Ro, Gangnamgu, Seoul, Republic of Korea.
AJR Am J Roentgenol. 2016 Feb;206(2):291-300. doi: 10.2214/AJR.15.14974.
The purpose of this study was to assess value of contrast-enhanced MRI, MRCP, and DWI for differentiating mass-forming autoimmune pancreatitis (AIP) from pancreatic ductal adenocarcinoma (PDAC).
This study included 15 patients with mass-forming AIP and 79 with PDAC who underwent gadoxetic acid-enhanced MRI with DWI and MRCP. Two radiologists evaluated the MRI findings in consensus. Statistically significant imaging findings were identified through univariate and multivariate analyses, and their diagnostic performance for predicting mass-forming AIP was analyzed.
In the univariate analysis, multiplicity, similar or high signal intensity on portal phase and 3- and 20-minute delayed phase images, homogeneous enhancement, no peripancreatic fat infiltration, no internal cystic or necrotic portion, capsulelike rim, no upstream pancreatitis, no vascular invasion, and duct penetrating sign were more frequently observed (p < 0.05) in mass-forming AIP. The apparent diffusion coefficient (ADC) value was also significantly lower for mass-forming AIP than for PDAC (0.96 ± 0.14 versus 1.13 ± 0.23 × 10(-3) mm(2)/s; p < 0.001). The optimal cutoff value of ADC for differentiating mass-forming AIP from PDAC was 0.9407 × 10(-3) mm(2)/s. In multivariate analysis, homogeneous enhancement (p = 0.001), duct penetrating sign (p < 0.001), and ADC value less than 0.9407 × 10(-3) mm(2)/s (p < 0.001) were significant for differentiating mass-forming AIP from PDAC. When two of these three criteria were combined, 80% (12/15) of mass-forming AIPs were identified with specificity of 98.7%. When all three criteria were satisfied, specificity was 100%.
Contrast-enhanced MRI with MRCP and DWI may be helpful for differentiating mass-forming AIP from PDAC.
本研究旨在评估对比增强 MRI、MRCP 和 DWI 对鉴别肿块型自身免疫性胰腺炎（AIP）与胰腺导管腺癌（PDAC）的价值。
本研究纳入了 15 例肿块型 AIP 患者和 79 例 PDAC 患者，均行钆塞酸增强 MRI 联合 DWI 和 MRCP 检查。两名放射科医生进行了 MRI 结果的一致性评估。通过单因素和多因素分析确定了具有统计学意义的影像学表现，并分析了其对预测肿块型 AIP 的诊断性能。
在单因素分析中，肿块型 AIP 更常表现为多发病灶、门脉期及 3 分钟和 20 分钟延迟期图像上相似或高信号强度、均匀强化、无胰周脂肪浸润、无内部囊变或坏死部分、包膜样边缘、无上游胰腺炎、无血管侵犯和胆管穿透征（p < 0.05）。与 PDAC 相比，肿块型 AIP 的表观扩散系数（ADC）值也显著降低（0.96 ± 0.14 比 1.13 ± 0.23×10(-3)mm(2)/s；p < 0.001）。用于鉴别肿块型 AIP 与 PDAC 的 ADC 最佳截断值为 0.9407×10(-3)mm(2)/s。多因素分析显示，均匀强化（p = 0.001）、胆管穿透征（p < 0.001）和 ADC 值小于 0.9407×10(-3)mm(2)/s（p < 0.001）是鉴别肿块型 AIP 与 PDAC 的重要因素。当这三个标准中的两个结合时，80%（12/15）例肿块型 AIP 具有 98.7%的特异性。当所有三个标准均满足时，特异性为 100%。
增强 MRI 联合 MRCP 和 DWI 有助于鉴别肿块型 AIP 与 PDAC。
