7 / 2021-08-23 20:19:11

The Comparative Investigation of Diagnostic Performance of Diffusion Weighted Imaging in the Differential Diagnosis of Benign and Malignant Sinonasal Tumours Between Different Selection Methods of Region of Interest

sinonasal tumours,magnetic resonance imaging,diffusion-weighted imaging,apparent diffusion coefficient,region of interest,observer variation

Abstract

Purpose

To compare the apparent diffusion coefficients (ADCs) calculated from diffusion weighted imaging (DWI) of sinonasal tumours (SNTs) using different methods to select the region of interest (ROI), and assess the diagnostic performance of ADCs of different ROI selection methods in differentiating benign and malignant SNTs.

Methods

DWI of 324 patients with pathology-proven SNTs were retrospectively evaluated. ADCs were calculated from the maximum-slice ROI (ROIms) and small solid sample ROI (ROIsss) drawn on ADC map by two radiologists. The mean ADCs and ADC ratios (ADCr= mean ADC of the tumour/mean ADC of the pons) of the tumours using two ROI selection methods were compared by the Mann–Whitney U-test. Diagnostic performances of ADCs using different ROI selection methods were compared by receiver operating characteristic curves. Inter-observer variability was evaluated using the interclass correlation coefficient (ICC) and Bland–Altman method.

Results

The mean ADCs of benign and malignant SNTs obtained using ROIsss method were significantly lower than those obtained using ROIms method (P<0.001). Both methods showed lower mean ADCs and ADCr for malignant SNTs than those for benign SNTs (P<0.001). The ROIms method showed excellent reproducibility (average differences and limits of agreement between readers were −0.00 [−0.30 to 0.29] ×10⁻³mm²/s [ICC=0.929]). Sensitivity, specificity, and accuracy of ADCs in differentiating benign and malignant SNTs using ROIms method was 83.6%, 84.7%, and 84.2%, respectively while sensitivity, specificity, and accuracy of ADCs using ROIsss method was 82.8%, 89.5%, and 86.6%, respectively. However, there was no significant difference in the diagnostic performance of ADCs and ADCr between two ROI selection methods (mean ADC: P=0.149; ADCr: P=0.054).

Conclusion

ADCs and ADCr of the tumour can accurately differentiate benign and malignant SNTs, in which the diagnostic performance was not affected by ROI selection methods. However, ROIms selection method was recommended because of its excellent inter-observer variability.