Role of MR diffusion weighted imaging in characterization of sinonasal lesions / Mostafa Mohamed Ahmed Elkhashab ; Supervised Ramy Edward Assad , Ayda Aly Youssef , Talaat Ahmed Hassan

Thesis (Ph.D.) - Cairo University - Faculty of Medicine - Department of Radio-diagnosis

Background: Differentiating benign from malignant sinonsal lesions is essential for treatment planning as well as determining the patient{u2019}s prognosis, but such differentiation is often difficult. In our study we aim to evaluate the role of diffusion weighted imaging (DWI) and apparent diffusion coefficient (ADC) in characterizing sinonasal lesions. Materials and methods: A perspective study including 75 treatment naive patients (36 benign and 39 malignant) underwent magnetic resonance imaging (MRI), including DWI using b-values of 500 and 1000 s/mm2. Freehand regions of interest along the margins of the lesions were manually placed onto the ADC maps then average ADCs of the whole lesions were determined. Receiver operating characteristic (ROC) curve was drawn to determine a cut-off ADC value for the differentiation between benign and malignant masses. Results: The mean ADC value for malignant lesions (0.67x10-3 mm2/sec) were significantly lower than the mean ADC value for benign lesions (1.25x10-3mm2/sec) (P <0.0001). When a cut-off ADC value 0.995 {u00D7}10-3 mm2/sec was used, sensitivity and specificity were 92.3%, 77.8% respectively with 81.8% positive predictive value and 90.3% negative predicative value, which was statistically significant. ADCs also effectively discriminated lymphomas from other malignant tumors

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