Differentiating focal autoimmune pancreatitis and pancreatic ductal adenocarcinoma: contrast-enhanced MRI with special emphasis on the arterial phase
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To compare focal-type autoimmune pancreatitis (AIP) and pancreatic ductal adenocarcinoma (PDA) using contrast-enhanced MR imaging (CE-MRI), and to assess diagnostic performance of the lesion contrast at arterial phase (AP) (ContrastAP) for differentiating between the two diseases.
Thirty-six patients with focal-type AIP and 72 patients with PDA were included. All included patients underwent CE-MRI with triple phases. The signal intensity (SI) of the mass and normal pancreas was measured at each phase, and the lesion contrast (SIpancreas/SImass) was compared between AIP and PDA groups. The sensitivity and specificity of ContrastAP using an optimal cutoff point were compared with those of key imaging features specific to AIP and PDA.
The lesion contrast differed significantly between AIP and PDA groups at all phases of CE-MRI; the maximum difference was observed at AP. For AIP, the sensitivity (94.4%) and specificity (87.5%) of ContrastAP (cutoff ≤ 1.41) were comparable or significantly higher than those of all key imaging features (sensitivity, 38.9–88.9%; specificity, 48.6–95.8%), except for the halo sign. For PDA, the sensitivity (87.5%) and specificity (94.4%) of ContrastAP (cutoff > 1.41) were comparable or significantly higher than those of all key imaging features (sensitivity, 40.3–68.1%; specificity, 72.2–94.4%), except for the discrete mass.
Quantitative analysis of the lesion contrast using CE-MRI, particularly at AP, was helpful to differentiate focal-type AIP from PDA. The diagnostic performance of ContrastAP was mostly comparable or higher than those of the key imaging features.
• Diagnosis of focal-type AIP vs. PDA using imaging techniques is extremely challenging.
• Lesion contrast in the arterial-phase MRI differs significantly between focal-type AIP and PDA.
• Quantitative analysis of lesion contrast using CE-MRI, particularly at the arterial phase, is helpful to differentiate focal-type AIP from PDA.
KeywordsPancreatic neoplasms Pancreatitis Autoimmune disease Carcinoma, pancreatic ductal Magnetic resonance imaging
Area under receiver operating characteristic curve
Contrast-enhanced magnetic resonance imaging
Main pancreatic duct
Pancreatic ductal adenocarcinoma
Receiver operating characteristic
Region of interest
The authors state that this work has not received any funding.
Compliance with ethical standards
The scientific guarantor of this publication is Jin Hee Kim.
Conflict of interest
The authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article.
Statistics and biometry
No complex statistical methods were necessary for this paper.
Written informed consent was waived by the Institutional Review Board.
Institutional Review Board approval was obtained.
• performed at one institution
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