Utility of diffusion-weighted imaging in the diagnosis of acute appendicitis

Eur Radiol. 2011 Apr;21(4):768-75. doi: 10.1007/s00330-010-1981-6. Epub 2010 Oct 6.


Objectives: To evaluate the value of diffusion-weighted MRI (DWI) in the diagnosis of acute appendicitis.

Methods: 119 patients with acute appendicitis and 50 controls were enrolled in this prospective study. DWI was obtained with b factors 0, 500 and 1000 s/mm² and were assessed with a visual scoring system by two radiologists followed by quantitative evaluation of the DW images and ADC maps.

Results: Histopathology revealed appendicitis in 79/92 patients (78%) who had undergone surgery. On visual evaluation, except for one patient with histopathologically proven appendicitis all inflamed appendixes were hyperintense on DWI (98.7%). Quantitative evaluation with DW signal intensities and ADC values revealed a significant difference with normal and inflamed appendixes (p < 0.001). The best discriminative parameter was signal intensity (b 500). With a cut-off value of 56 for the signal intensity the ratio had a sensitivity of 99% and a specificity of 97%. The cut-off ADC value at 1.66 mm²/s had a sensitivity of 97% and a specificity of 99%.

Conclusion: DWI is a valuable technique for the diagnosis of acute appendicitis with both qualitative and quantitative evaluation. DWI increases the conspicuity of the inflamed appendix. We recommend using DWI to diagnose acute appendicitis.

MeSH terms

  • Acute Disease
  • Adolescent
  • Adult
  • Aged
  • Appendicitis / diagnostic imaging*
  • Appendicitis / pathology*
  • Appendicitis / surgery
  • Diffusion Magnetic Resonance Imaging / methods*
  • Female
  • Humans
  • Image Processing, Computer-Assisted
  • Inflammation
  • Magnetic Resonance Imaging / methods
  • Male
  • Middle Aged
  • Observer Variation
  • Predictive Value of Tests
  • Prospective Studies
  • Radiography
  • Reproducibility of Results
  • Sensitivity and Specificity