Introduction: Cholesteatoma is a retraction pocket or cyst lined by squamous epithelium containing keratin debris occurring in the pneumatized portions of temporal bone, have a propensity for growth, bone destruction and is considered “unsafe” ear requires surgical treatment. High resolution CT is the method of choice for imaging cholesteatoma, but it cannot differentiate cholesteatoma from other soft tissues or mucoid secretions, especially in patients who have previous surgery, thus diffusion weighted MRI (DW-MRI) is recently used for differentiating cholesteatoma from other pathologies. 

Objectives: We aimed to evaluate the role of DW-MRI in diagnosis of de novo and recurrent cholesteatoma. 

Patients and Methods: We enrolled forty patients with suspected cholesteatoma either de novo or recurrent. All patients were subjected to complete history taking, otoscopic examination, HRCT scan and DW- MRI scanning with calculation of the apparent diffusion co-efficient (ADC). Then, surgical exploration of the middle ear was done, and we correlated between the operative and DW-MRI results. 

Results: We found ADC values ranged between 0.1-1.7 with median ADC value was 0.8 mm2/s. ADC cut-off point for detecting cholesteatoma was 0.8. P values for ADC, were significant for both denovo and recurrent cases, 0.044 and 0.039 respectively. Also, we found that DW-MRI had a sensitivity of (83%), specificity (75%), PPV (88%), NPV (67%) for detection of cholesteatoma in de novo cases, and a sensitivity of (80%), specificity (75%), PPV (89%) and NPV (60%) for recurrent cases. 

Conclusion: DW-MRI could be a sensitive non-invasive tool for detecting cholesteatoma.