The Value of Adding MR Diffusion Weighted Imaging to the Conventional Post Contrast MRI Study in Characterization of Sino-nasal Lesions
Background: Diffusion Weighted (DW) MRI, which was used to quantify the diffusional motion of water with the Apparent Diffusion Coefficient (ADC), has also been employed for diagnosing head and neck lesions. Previous studies reported that ADCs were useful in discrimination not only between benign and malignant tumors. We conducted the present study to assess the value of adding Diffusion-Weighted Magnetic Resonance Imaging (DW-MRI) and calculated Apparent Diffusion Coefficient (ADC) values in characterization of sinonasal lesions regarding differentiating benign from the malignant lesions.
Patients and methods: The present prospective study was conducted on 75 patients (with a mean age of 26.40 ± 25.2 year old; the majority of patients were females (58.7%)) who presented with sinonasal masses to the National Cancer Institute in Cairo during the period from June 2018 to June 2019. The following data were collected from eligible patients demographic characteristics, history related to sinonasal masses, conventional MRI characteristics of sinonasal masses, DW-MRI findings, and pathological diagnosis.
Results: Overall 52% of the patients had malignant masses. By Contrast-Enhanced MRI alone, 49 malignant- looking lesions were detected; after pathological analysis, only 33 proved to be truly positive for malignancy. Thus, using Contrast-Enhanced MRI in predicting benign and malignant lesions has the sensitivity of 84.6% and specificity of 55.6% with 67.3% positive predictive value and 76.9% negative predicative value. The calculated ADC value of the lesion was found to be statically significant different between the benign and malignant lesions. The malignant lesions had significantly lower ADC value. The ADC value of 0.99 × 10-3mm2/sec was suggested as the optimal cut-off between benign and malignant entities, with 92.3% sensitivity and 77.8% specificity.
Conclusion: DW-MRI and ADC values improves the diagnostic accuracy of imaging modalities in differentiation between the benign and malignant sinonasal masses.