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Meta-Analysis of Apparent Diffusion Coefficient in Pediatric Medulloblastoma, Ependymoma, and Pilocytic Astrocytoma

Dury, Richard J.; Lourdusamy, Anbarasu; Macarthur, Donald C.; Peet, Andrew C.; Auer, Dorothee P.; Grundy, Richard G.; Dineen, Robert A.

Meta-Analysis of Apparent Diffusion Coefficient in Pediatric Medulloblastoma, Ependymoma, and Pilocytic Astrocytoma Thumbnail


Richard J. Dury

Donald C. Macarthur

Andrew C. Peet

Professor of Neuroimaging

Professor of Paediatric Neuro-Oncology

Professor of Neuroradiology


Background: Medulloblastoma, ependymoma, and pilocytic astrocytoma are common pediatric posterior fossa tumors. These tumors show overlapping characteristics on conventional MRI scans, making diagnosis difficult. Purpose: To investigate whether apparent diffusion coefficient (ADC) values differ between tumor types and to identify optimum cut-off values to accurately classify the tumors using different performance metrics. Study type: Systematic review and meta-analysis. Subjects: Seven studies reporting ADC in pediatric posterior fossa tumors (115 medulloblastoma, 68 ependymoma, and 86 pilocytic astrocytoma) were included following PubMed and ScienceDirect searches. Sequence and Field Strength: Diffusion weighted imaging (DWI) was performed on 1.5 and 3T across multiple institution and vendors. Assessment: The combined mean and standard deviation of ADC were calculated for each tumor type using a random-effects model, and the effect size was calculated using Hedge's g. Statistical Tests: Sensitivity/specificity, weighted classification accuracy, balanced classification accuracy. A P value < 0.05 was considered statistically significant, and a Hedge's g value of >1.2 was considered to represent a large difference. Results: The mean (± standard deviation) ADCs of medulloblastoma, ependymoma, and pilocytic astrocytoma were 0.76 ± 0.16, 1.10 ± 0.10, and 1.49 ± 0.16 mm2/sec× 10−3. To maximize sensitivity and specificity using the mean ADC, the cut-off was found to be 0.96 mm2/sec× 10−3 for medulloblastoma and ependymoma and 1.26 mm2/sec× 10−3 for ependymoma and pilocytic astrocytoma. The meta-analysis showed significantly different ADC distributions for the three posterior fossa tumors. The cut-off values changed markedly (up to 7%) based on the performance metric used and the prevalence of the tumor types. Data Conclusion: There were significant differences in ADC between tumor types. However, it should be noted that only summary statistics from each study were analyzed and there were differences in how regions of interest were defined between studies. Evidence Level: 1. Technical Efficacy: Stage 3.

Journal Article Type Article
Acceptance Date Nov 16, 2021
Online Publication Date Nov 29, 2021
Publication Date Jul 1, 2022
Deposit Date Nov 25, 2021
Publicly Available Date Nov 30, 2022
Journal Journal of Magnetic Resonance Imaging
Print ISSN 1053-1807
Electronic ISSN 1522-2586
Peer Reviewed Peer Reviewed
Volume 56
Issue 1
Pages 147-157
Keywords Radiology Nuclear Medicine and imaging
Public URL
Publisher URL
Additional Information This is the peer reviewed version of the following article: Dury, R.J., Lourdusamy, A., Macarthur, D.C., Peet, A.C., Auer, D.P., Grundy, R.G. and Dineen, R.A. (2022), Meta-Analysis of Apparent Diffusion Coefficient in Pediatric Medulloblastoma, Ependymoma, and Pilocytic Astrocytoma. J Magn Reson Imaging, 56: 147-157, which has been published in final form at This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited


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