Differentiation between pancreatic carcinoma and mass-forming chronic pancreatitis: usefulness of high b value diffusion-weighted imaging

Abstract

Objective: To investigate the value of high b value diffusion-weighted (DW) imaging in differentiating between pancreatic carcinoma and mass-forming chronic pancreatitis (MFCP).

Methods: Fifty-one consecutive patients with pathology-proven pancreatic carcinoma (n = 37) or MFCP (n = 14) were evaluated with DW imaging (b value, 0 and 1000 s/mm(2)) at a 3-T MR system. Overall 20 healthy volunteers were evaluated as the control group. The apparent diffusion coefficient (ADC) values of normal pancreas, pancreatic carcinoma, MFCP, and mass-associated obstructive pancreatitis were measured.

Results: On high b value (1000 s/mm(2) ) DW images, both pancreatic carcinoma and MFCP were hyperintense focal lesions; mass-associated obstructive pancreatitis occurred in 17 of 37 (45.9%) pancreatic carcinoma and 8 of 14 (57.1%) MFCP. The ADC (×10(-3) mm(2) /s) of the pancreatic carcinomas (1.06 ± 0.15) was significantly lower than that of normal pancreas (1.47 ± 0.18; P < 0.01), MFCP (1.35 ± 0.14; P < 0.01) and mass-associated chronic pancreatitis (1.44 ± 0.17; P < 0.01). The ADC of MFCP was also lower than that in the normal pancreas (P = 0.025), whereas the ADC of mass-associated obstructive pancreatitis was not different from those of the MFCP (P = 0.113) and normal pancreas (P = 0.544). When 1.195 was used as the optimal cut-off value, ADC quantification obtained a sensitivity of 85.7% and a specificity of 86.5% for differentiating pancreatic carcinomas from MFCP.

Conclusion: High b value DW imaging in combination with ADC quantification at a 3-T MR system is useful in differentiating between pancreatic carcinoma and MFCP.