Diagnostic accuracy of apparent diffusion coefficient (ADC) in differentiating low- and high-grade gliomas, taking histopathology as the gold standard

Abstract

Gliomas are known to be one of the most grievous malignant central nervous system (CNS) tumors and have a high mortality rate with a low survival rate severe disability and increase risk of recurrence. Aim of his study is to determine the diagnostic accuracy of apparent diffusion coefficient (ADC) in differentiating low-grade and high-grade gliomas, taking histopathology as the gold standard. It is a Cross-sectional validation study conducted at the Armed Forces Institute of Radiology and Imaging, (AFIRI) Rawalpindi, Pakistan from 28th February 2022 to 27th August 2022. Materials and methods: A total of 215 patients with focal brain lesions of age 25-65 years of either gender were included. Patients with a cardiac pacemaker, breastfeeding females, de-myelinating lesions and malignant infiltrates, and renal failure were excluded. Then diffusion-weighted magnetic resonance imaging was performed on each patient by using a 1.5 Tesla MR system. The area of greatest diffusion restriction (lowest ADC) within the solid tumor component was identified while avoiding areas of peritumoral edema. Results of ADC were interpreted by a consultant radiologist (at least 5 years of post-fellowship experience) for high or low-grade glioma. After this, each patient has undergone a biopsy in the concerned ward, and histopathology results were compared with ADC findings. Results: Overall sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of apparent diffusion coefficient (ADC) in differentiating low- and high-grade gliomas, taking histopathology as the gold standard was 93.65%, 87.64%, 91.47%, 90.70% and 91.16% respectively. Conclusion: This study concluded that apparent diffusion coefficient (ADC) is the non-invasive modality of choice with high diagnostic accuracy in differentiating low- and high-grade gliomas.