PURPOSE: To clarify whether there are differences in MRI findings between pancreatic lymphomas and autoimmune pancreatitis (AIP). MATERIALS AND METHODS: MRI of 8 patients with pancreatic lymphomas and 21 patients with AIP were retrospectively reviewed. For multifocal pancreatic lymphomas (n=2) and AIP (n=4), the largest 2 lesions were evaluated. Ten pancreatic lymphomas and 25 AIP were compared on three bases: the signal intensity on T2-weighted images, internal homogeneity, and presence or absence of capsule-like rim. In 8 lymphomas and 19 AIP, the enhancement pattern on dynamic MRI was compared, as well. RESULTS: On T2-weighted images, pancreatic lymphomas comprised 5, 5 and 4 lesions with low (iso), slightly high, and moderately high intensity, respectively, while the numbers for AIP were 14, 10, and 1 (P<0.01). Nine of 10 (90%) lymphomas appeared homogenous, and 11 of 25 (44%) AIP were homogenous (P<0.05). A capsule-like rim was present in 9 of 25 (36%) AIP, but was not seen in lymphomas (P<0.05). On dynamic MRI, 18 of 19 (94.7%) AIP showed persistent (n=5) or delayed enhancement (n=13), and 6 of 8 (75%) lymphomas showed low intensity without delayed enhancement (P<0.001). CONCLUSION: MRI findings for pancreatic lymphomas and AIP were significantly different, which may be helpful for the differential diagnosis of these two diseases. Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.
PURPOSE: To clarify whether there are differences in MRI findings between pancreatic lymphomas and autoimmune pancreatitis (AIP). MATERIALS AND METHODS: MRI of 8 patients with pancreatic lymphomas and 21 patients with AIP were retrospectively reviewed. For multifocal pancreatic lymphomas (n=2) and AIP (n=4), the largest 2 lesions were evaluated. Ten pancreatic lymphomas and 25 AIP were compared on three bases: the signal intensity on T2-weighted images, internal homogeneity, and presence or absence of capsule-like rim. In 8 lymphomas and 19 AIP, the enhancement pattern on dynamic MRI was compared, as well. RESULTS: On T2-weighted images, pancreatic lymphomas comprised 5, 5 and 4 lesions with low (iso), slightly high, and moderately high intensity, respectively, while the numbers for AIP were 14, 10, and 1 (P<0.01). Nine of 10 (90%) lymphomas appeared homogenous, and 11 of 25 (44%) AIP were homogenous (P<0.05). A capsule-like rim was present in 9 of 25 (36%) AIP, but was not seen in lymphomas (P<0.05). On dynamic MRI, 18 of 19 (94.7%) AIP showed persistent (n=5) or delayed enhancement (n=13), and 6 of 8 (75%) lymphomas showed low intensity without delayed enhancement (P<0.001). CONCLUSION: MRI findings for pancreatic lymphomas and AIP were significantly different, which may be helpful for the differential diagnosis of these two diseases. Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.