The Usefulness of Diffusion-Weighted Imaging (DWI) and Apparent Diffusion Coefficient (ADC) Value for the Diagnosis and the Assessment of the Therapeutic Effect on Autoimmune Pancreatitis (AIP)

Keizo Tanitame¹, Yuko Nakamura¹, Yoko Kaichi¹, Chihiro Tani¹, Yukiko Honda¹, Miyuki Takasu¹, Kazuo Awai¹

Problem: To compare the ADC values of AIP and pancreatic carcinoma and investigate their usefulness in IgG4-related AIP during steroid therapy. Methods: ADC values were compared among 10 patients with IgG4-related AIP, 7 with IgG4-negative AIP, 27 with carcinoma. In 6 patients with IgG4-related AIP ADC values were followed during steroid therapy. Results: The ADC values were significantly lower in IgG4-related and -negative AIP than carcinoma (p<0.01, each). ADC values increased during the therapy in all patients with IgG4-related AIP. Conclusion: ADC value was useful for differentiating between AIP and pancreatic carcinoma and for assessing the effects of steroid therapy.