The value of diffusion-weighted imaging and apparent diffusion coefficient quantification in the diagnosis of perforated and nonperforated appendicitis.

PURPOSE We aimed to evaluate the effectiveness of diffusion-weighted magnetic resonance imaging (DW-MRI) and apparent diffusion coefficient (ADC) values in the diagnosis of acute appendicitis and differentiation of perforated and nonperforated appendicitis cases, with histopathologic correlation. MATERIALS AND METHODS Sixty consecutive patients (34 males, 26 females; mean age, 35.6±15.5 years; range, 17-83 years) with a presumptive diagnosis of acute appendicitis were included in this prospective study. With a 1.5 Tesla MRI unit, DW-MRI examinations were performed with b values of 50, 400, and 800 s/mm(2). The mean ADC values of case and control groups, as well as in perforated and nonperforated groups were compared. RESULTS Of the 60 cases, 44 had a radiological diagnosis of acute appendicitis, and 16 were regarded as normal. Of the 40 patients who underwent surgical operation, 12 had a histopathological diagnosis of perforated appendicitis, and 28 had nonperforated appendicitis. Mean ADC value in patients with acute appendicitis (1.01±0.26×10(-3) mm(2)/s) was lower than the control group (1.85±0.13×10(-3) mm(2)/s) (P < 0.001). Mean ADC value of the perforated group (0.79±0.19×10(-3) mm(2)/s) was lower than the nonperforated group (1.11±0.22×10(-3) mm(2)/s) (P < 0.001). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy rate of DW-MRI in the diagnosis of acute appendicitis were 97.5%, 100%, 97.5%, 100%, and 98.1%, respectively. CONCLUSION DW-MRI and ADC quantification are effective in the diagnosis of acute appendicitis, both in perforated and nonperforated cases.