Findings on Preoperative Brain MRI Predict Histopathology in Children with Cerebellar Neoplasms

Abstract

Background/Aims: The majority of pediatric patients with cerebellar neoplasms harbor pilocytic astrocytomas (PAs), medulloblastomas, or ependymomas. Knowledge of a preoperative likelihood of histopathology in this group of patients has the potential to influence many aspects of care. Previous studies have demonstrated hyperintensity on diffusion-weighted imaging to correlate with medulloblastomas. Recently, measurement of T₂-weighted signal intensity (T2SI) was shown to be useful in identification of low-grade cerebellar neoplasms. The goal of this study was to assess whether objective findings on these MRI sequences reliably correlated with the underlying histopathology. Methods: We reviewed the radiologic findings of 50 pediatric patients who underwent resection of a cerebellar neoplasm since 2003 at our institution. Region of interest placement was used to calculate the relative diffusion-weighted signal intensity (rDWSI) and relative T2SI (rT2SI) of each neoplasm. Results: Tukey’s multiple comparison test demonstrated medulloblastomas to have significantly higher rDWSIs than PAs/ependymomas, and PAs to have significantly higher rT2SIs than medulloblastomas/ependymomas. A simple method consisting of sequential measurement of rDWSI and rT2SI to predict histopathology was then constructed. Using this method, 39 of 50 (78%) tumors were accurately predicted. Conclusion: Measurement of rDWSI and rT2SI using standard MRI of the brain can be used to predict histopathology with favorable accuracy in pediatric patients with cerebellar tumors.

The Diagnostic Efficiency of Quantitative Diffusion Weighted Imaging in Differentiating Medulloblastoma from Posterior Fossa Tumors: A Systematic Review and Meta-Analysis

“…Sixty-three articles were excluded by full-text review for the following reasons: 24 articles did not have enough data for calculation or construction of TP, FP, TN, and FN values; 9 articles used machine learning for analysis, 17 articles did not include MB, and 13 articles only identified high and low grade or benign and malignant tumors. Finally, a total of 15 studies was included for quantitative analysis [ 3 , 17 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ].…”

“…The majority of the studies had high quality with a low risk of bias. All studies except two [ 30 , 32 ] did not report whether diagnostic thresholds were predetermined, so we marked them [ 3 , 17 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 31 , 33 , 34 , 35 ] as unclear risks of the index bias domain. Two studies [ 24 , 28 ] had a high risk of fluid and timing bias because the number of individual tumor types enrolled did not reach the basic level of statistical analysis.…”

Pediatric low-grade glioma

“…The enhancement pattern, the presence or absence of a distinct tumor margin, and invasiveness may suggest a particular diagnosis. Forbes et al reported that a relatively higher diffusion-weighted imaging signal is associated with high-grade posterior fossa tumors such as medulloblastoma rather than LGG [3]. Grade 1 gliomas are usually associated with contrast uptake, whereas grade 2 gliomas usually do not take up contrast.…”

The effect of semi-quantitative T1-perfusion parameters for the differentiation between pediatric medulloblastoma and ependymoma

“…Several studies have utilized MRI to distinguish between medulloblastoma and ependymoma. However, the results of some studies have shown several overlapping imaging characteristics between these two tumor types; therefore, differentiating between medulloblastoma and ependymoma remains an ongoing concern that is currently being studied [7][8][9][10][11][12][13].…”