Optic nerve head diffusion-weighted magnetic resonance imaging and apparent diffusion coefficient values as measuring tools for papilledema grade in idiopathic intracranial hypertension

Abstract

Aim The aim of this study was to explore if there is a relationship between the grade of papilledema and MRI diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) values of the optic nerve head (ONH) in patients having idiopathic intracranial hypertension (IIH). Patients and methods This is a prospective study that was conducted between March 2020 and June 2022 on 285 patients diagnosed as having IIH, who were subjected to meticulous clinical examination, visual field testing, color vision testing, and orbital MRI done within one week of diagnosis. ONH signal intensity was graded and then compared with papilledema grade, and the results were analyzed. Results The study included 285 patients (156 females and 129 males), with a mean age of 30.8±9.6 years, definitely diagnosed as having IIH with lumbar puncture opening pressure ranging from 18 to 58 cmH2O (mean=35.6±9.8 cmH2O). The papilledema grades were grade I (121 patients), grade II (136 patients), grade III (21 patients), and grade IV (seven patients). ADC values of the ONH were found to be gradually decreased with higher papilledema grades among cases. In addition, according to papilledema grading, in grade I, 67% of the patients showed no DWI changes, whereas in grade II, 97% of the patients showed DWI changes in the ONH. In grades III and IV, all patients showed DWI changes. Conclusion MRI can be considered as a diagnostic tool for papilledema. In addition, low ADC values and diffusion restriction can be used as indicators for the severity of ONH insult in cases of increased intracranial tension.