Characterization of Active and Infiltrative Tumorous Subregions From Normal Tissue in Brain Gliomas Using Multiparametric MRI

Anahita Fathi Kazerooni, PhD, Mahnaz Nabil, PhD, Mehdi Zeinali Zadeh, MD, Kavous Firouznia, MD, Farid Azmoudeh-Ardalan, MD, Alejandro F. Frangi, PhD, Christos Davatzikos, PhD and Hamidreza Saligheh Rad, PhD


Background: Targeted localized biopsies and treatments for diffuse gliomas rely on accurate identification of tissue subregions, for which current MRI techniques lack specificity.
Purpose: To explore the complementary and competitive roles of a variety of conventional and quantitative MRI methods for distinguishing subregions of brain gliomas.
Study Type: Prospective.
Population: Fifty-one tissue specimens were collected using image-guided localized biopsy surgery from 10 patients
with newly diagnosed gliomas.
Field Strength/Sequence: Conventional and quantitative MR images consisting of pre- and postcontrast T1w, T2w, T2- FLAIR, T2-relaxometry, DWI, DTI, IVIM, and DSC-MRI were acquired preoperatively at 3T.
Assessment: Biopsy specimens were histopathologically attributed to glioma tissue subregion categories of active
tumor (AT), infiltrative edema (IE), and normal tissue (NT) subregions. For each tissue sample, a feature vector comprising 15 MRI-based parameters was derived from preoperative images and assessed by a machine learning algorithm to determine the best multiparametric feature combination for characterizing the tissue subregions.
Statistical Tests: For discrimination of AT, IE, and NT subregions, a one-way analysis of variance (ANOVA) test and for pairwise tissue subregion differentiation, Tukey honest significant difference, and Games-Howell tests were applied (P<0.05). Cross-validated feature selection and classification methods were implemented for identification of accurate multiparametric MRI parameter combination. Results: After exclusion of 17 tissue specimens, 34 samples (AT56, IE520, and NT58) were considered for analysis. Highest accuracies and statistically significant differences for discrimination of IE from NT and AT from NT were observed for diffusion-based parameters (AUCs >90%), and the perfusion-derived parameter as the most accurate feature in distinguishing IE from AT. A combination of “CBV, MD, T2_ISO, FLAIR” parameters showed high diagnostic performance for identification of the three subregions (AUC 90%).
Data Conclusion: Integration of a few quantitative along with conventional MRI parameters may provide a potential
multiparametric imaging biomarker for predicting the histopathologically proven glioma tissue subregions.