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J Neurooncol. 2018 Apr;137(2):313-319. doi: 10.1007/s11060-017-2719-y. Epub 2018 Jan 30.

Normalization of ADC does not improve correlation with overall survival in patients with high-grade glioma (HGG).

Qin L1,2, Li A3,4, Qu J3,5, Reinshagen K2,3,6, Li X3,5, Cheng SC7, Bryant A1,8, Young GS9,10,11.

Author information

1
Department of Imaging, Dana-Farber Cancer Institute, Boston, MA, USA.
2
Department of Radiology, Harvard Medical School, Boston, MA, USA.
3
Department of Radiology, Brigham and Women's Hospital, 75 Francis Street, Boston, MA, 02115, USA.
4
The Robert Larner, M.D. College of Medicine, University of Vermont, Burlington, VT, USA.
5
Department of Radiology, Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou, Henan, China.
6
Department of Radiology, Massachusetts Eye and Ear Infirmary, Boston, MA, USA.
7
Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute, Boston, MA, USA.
8
Department of Behavioral Neuroscience, Northeastern University, Boston, MA, USA.
9
Department of Imaging, Dana-Farber Cancer Institute, Boston, MA, USA. gsyoung@partners.org.
10
Department of Radiology, Harvard Medical School, Boston, MA, USA. gsyoung@partners.org.
11
Department of Radiology, Brigham and Women's Hospital, 75 Francis Street, Boston, MA, 02115, USA. gsyoung@partners.org.

Abstract

Mixed reports leave uncertainty about whether normalization of apparent diffusion coefficient (ADC) to a within-subject white matter reference is necessary for assessment of tumor cellularity. We tested whether normalization improves the previously reported correlation of resection margin ADC with 15-month overall survival (OS) in HGG patients. Spin-echo echo-planar DWI was retrieved from 3 T MRI acquired between maximal resection and radiation in 37 adults with new-onset HGG (25 glioblastoma; 12 anaplastic astrocytoma). ADC maps were produced with the FSL DTIFIT tool (Oxford Centre for Functional MRI). 3 neuroradiologists manually selected regions of interest (ROI) in normal appearing white matter (NAWM) and in non-enhancing tumor (NT) < 2 cm from the margin of residual enhancing tumor or resection cavity. Normalized ADC (nADC) was computed as the ratio of absolute NT ADC to NAWM ADC. Reproducibility of nADC and absolute ADC among the readers' ROI was assessed using intra-class correlation coefficient (ICC) and within-subject coefficient of variation (wCV). Correlations of ADC and nADC with OS were compared using receiver operating characteristics (ROC) analysis. A p value 0.05 was considered statistically significant. Both mean ADC and nADC differed significantly between patients subgrouped by 15-month OS (p = 0.0014 and 0.0073 respectively). wCV and ICC among the readers were similar for absolute and normalized ADC. In ROC analysis of correlation with OS, nADC did not perform significantly better than absolute ADC. Normalization does not significantly improve the correlation of absolute ADC with OS in HGG, suggesting that normalization is not necessary for clinical or research ADC analysis in HGG patients.

KEYWORDS:

ADC normalization; Apparent diffusion coefficient (ADC); Diffusion weighted imaging (DWI); High-grade glioma (HGG)

PMID:
29383647
PMCID:
PMC6071871
DOI:
10.1007/s11060-017-2719-y
[Indexed for MEDLINE]
Free PMC Article

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