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Differentiating low‐ and high‐grade pediatric brain tumors using a continuous‐time random‐walk diffusion model at high b ‐values
Author(s) -
Karaman M. Muge,
Sui Yi,
Wang He,
Magin Richard L.,
Li Yuhua,
Zhou Xiaohong Joe
Publication year - 2016
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.26012
Subject(s) - random walk , effective diffusion coefficient , receiver operating characteristic , grading (engineering) , diffusion , medicine , nuclear medicine , diffusion mri , mathematics , nuclear magnetic resonance , radiology , statistics , physics , magnetic resonance imaging , thermodynamics , civil engineering , engineering
Purpose To demonstrate that a continuous‐time random‐walk (CTRW) diffusion model can improve diagnostic accuracy of differentiating low‐ and high‐grade pediatric brain tumors. Methods Fifty‐four children with histopathologically confirmed brain tumors underwent diffusion MRI scans at 3Twith 12 b ‐values (0‐4000 s/mm 2 ). The diffusion imageswere fit to a simplified CTRW model to extract anomalous diffusion coefficient, D m , and temporal and spatial heterogeneity parameters, α and β , respectively. Using histopathology results as reference, a k ‐means clustering algorithm and a receiver operating characteristic (ROC) analysis were employed to determine the sensitivity, specificity, and diagnostic accuracy of the CTRW parameters in differentiating tumor grades. Results Significant differences between the low‐ and high‐grade tumors were observed in the CTRW parameters ( p ‐values<0.001). The k ‐means analysis showed that the combination of three CTRW parameters produced higher diagnostic accuracy (85% vs. 75%) and specificity (83% vs. 54%) than the apparent diffusion coefficient (ADC) from a mono‐exponential model. The ROC analysis revealed that any combination of the CTRW parameters gave a larger area under the curve (0.90‐0.96) than using ADC (0.80). Conclusion With its sensitivity to intravoxel heterogeneity, the simplified CTRW model is useful for non‐invasive grading of pediatric brain tumors, particularly when surgical biopsy is not feasible. Magn Reson Med 76:1149–1157, 2016. © 2015 Wiley Periodicals, Inc.