Archive | 2021
Diagnostic Performance of MRI Diffusion Weighted Heterogeneity Index to Discriminate Brain Metastases from Normal Brain Tissue in Hybrid PET/MR
Abstract
\n IntroductionTo evaluate diagnostic performance of apparent diffusion coefficient (ADC) heterogeneity index to differentiate brain metastasis (BM) from normal appearing brain parenchyma (NABP) and to find out the correlation between 2-[18F]-fluoro-2-deoxy-D-glucose (18F-FDG) standardized uptake value (SUV) and ADC heterogeneity index derived from hybrid PET/MRI.MethodsWhole-body PET/MRI was performed to evaluate proven 40 BM of 18 oncology patients (9 females, 9 males; mean age 61±16 years), sourced from different primary cancer. Brain sequences, which were dixon and diffusion weighted imaging (DWI) protocols with simultaneous PET were used to calculate coefficient of variance of the ADC (ADCCV) and SUVmax. All images were assessed by three radiologists and the same size of VOI was placed on BM and NABP. Inter-rater reliability was tested by inter-class correlation (ICC). The correlation of ADCCV and SUVmax and the differences in ADC values and SUVmax between BM and NABP were investigated.ResultsThe excellent consistency was found between raters at ADCmean (0.972) and ADCCV (0.995). There was a strong correlation between ADCCV and SUVmax (r=0.763) and a slight inverse correlation between ADCmean and SUVmax (r=-0.122). A statistically significant difference between BM and NABP was determined for ADCCV (p<0.001) and SUVmax (p<0.001). An area under the curve (AUC) of 0.960, 0.998 and 0.574 were obtained with ROC analysis of SUVmax, ADCCV and ADCmean, respectively.ConclusionADCCV may be considered as a potential biomarker that quantitatively discriminates BM from NABP with excellent interrater reliability.