Advanced MRI Findings in Medulloblastomas: Relationship to Genetic Subtypes, Histopathology, and Immunohistochemistry. Issue 2 (19th January 2021)

• Record Type: Journal Article
• Authors: Reis, Jonas; Stahl, Robert; Zimmermann, Hanna; Ruf, Viktoria; Thon, Niklas; Kunz, Mathias; Liebig, Thomas; Forbrig, Robert
• Is Part Of: Journal of neuroimaging. Volume 31:Issue 2(2021)
• Page Start: 306
• Page End: 316
• Publication Date: 2021-01-19
• Subjects: Apparent diffusion coefficient -- diffusion‐weighted imaging -- medulloblastoma -- molecular groups -- posterior fossa tumors; Diagnostic imaging -- Periodicals; Nervous system -- Diseases -- Diagnosis -- Periodicals; Imagerie pour le diagnostic -- Périodiques; Système nerveux -- Maladies -- Diagnostic -- Périodiques; Imagerie médicale; Neuroimagerie; Neurologie; Système nerveux; Périodique électronique (Descripteur de forme); Ressource Internet (Descripteur de forme); 616.804754
• DOI: 10.1111/jon.12831
• Languages: English
• ISSNs: 1051-2284

Abstract

ABSTRACT: BACKGROUND AND PURPOSE: For diagnosis of medulloblastoma, the updated World Health Organization classification now demands for genetic typing, defining more precisely the tumor biology, therapy, and prognosis. We investigated potential associations between magnetic resonance imaging (MRI) parameters including apparent diffusion coefficient (ADC) and neuropathologic features of medulloblastoma, focusing on genetic subtypes. METHODS: This study was a retrospective single‐center analysis of 32 patients (eight females, median age = 9 years [range, 1‐57], mean 12.6 ± 11.3) from 2012 to 2019. Genetic subtypes (wingless [WNT]; sonic hedgehog [SHH]; non‐WNT/non‐SHH), histopathology, immunohistochemistry (p53, Ki67), and the following MRI parameters were correlated: tumor volume, location (midline, pontocerebellar, and cerebellar hemisphere), edema, hydrocephalus, metastatic disease (presence/absence and each), contrast‐enhancement (minor, moderate, and distinct), cysts (none, small, and large), hemorrhage (none, minor, and major), and ADCmean . The ADCmean was calculated using manually set regions of interest within the solid tumor. Statistics comprised univariate and multivariate testing. RESULTS: Out of 32 tumors, three tumors were WNT activated (9.4%), 13 (40.6%) SHH activated, and 16 (50.0%) non‐WNT/non‐SHH. Hemispherical location ( n = 7/8, P = .003) and presence of edema (8/8; P < .001, specificity 100%, positive predictive value 100%) were significantly associated with SHH activation. The combined parameter "no edema + no metastatic disease + cysts" significantly discriminated WNT‐activated from SHH‐activated medulloblastoma ( P = .036). ADCmean (10 –6 mm 2 /s) was 484 for WNT‐activated, 566 for SHH‐activated, and 624 for non‐WNT/non‐SHH subtypes ( P = .080). A significant negative correlation was found between ADCmean and Ki67 ( r = –.364, P = .040). CONCLUSION: MRI analysis enabled noninvasive differentiation of SHH‐activated medulloblastoma. ADC alone was not reliable for genetic characterization, but associated with tumor proliferation rate.