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Updated: May 29, 2026
Diffusion Tensor Magnetic Resonance Imaging in the Analysis of Neurodegenerative Diseases
Published on: July 28, 2013
MRI apparent diffusion coefficient reflects histopathologic subtype, axonal disruption, and tumor fraction in
Inas S Khayal1, Scott R Vandenberg, Kenneth J Smith
1UCSF/UCB Joint Graduate Group in Bioengineering, University of California, San Francisco, CA, USA.
Abstract:
The apparent diffusion coefficient (ADC) determined from MR diffusion tensor imaging (DTI) has shown promise for distinguishing World Health Organization grade II astrocytoma (AS) from the more prognostically favorable grade II oligodendroglioma (OD). Since mixed oligoastrocytomas (OAs) with codeletions in chromosomes 1p and 19q confer prognoses similar to those of OD, we questioned whether a previously determined ADC-based criterion for distinguishing OD and AS would hold on an independent set of gliomas that included OA with codeleted or intact 1p/19q chromosomes. We also questioned whether the ADC is associated with the tumor microstructure. ADC colormaps generated from presurgical DTI scans were used to guide the collection of biopsies from each tumor. The median normalized ADC distinguished OD from AS with 91% sensitivity and 92% specificity. 1p/19q codeleted OAs were always classified as ODs, while 1p/19q intact OAs were always classified as ASs. There were positive associations between the ADC and both the SMI-31 score of axonal disruption and the fraction of tumor cells in the biopsies. The ADC of OD and 1p/19q codeleted OA was more associated with tumor fraction, while the ADC of AS and 1p/19q intact OA was more associated with SMI-31 score. We conclude that our previously determined threshold median ADC can distinguish grade II OD and AS on a new patient cohort and that the distinctions extend to OA with codeleted and intact 1p/19q chromosomes. Further, the ADC in grade II gliomas is associated with the fraction of tumor cells and degree of axonal disruption in tumor subregions.
Insights
Apparent diffusion coefficient (ADC) from MR diffusion tensor imaging reliably distinguishes grade II astrocytoma from oligodendroglioma, including mixed types. ADC also correlates with tumor microstructure and cell fraction.
Area of Science:
- Neuro-oncology
- Radiology
- Pathology
Background:
- Distinguishing World Health Organization (WHO) grade II astrocytoma (AS) from oligodendroglioma (OD) is critical due to differing prognoses.
- Mixed oligoastrocytomas (OAs) with 1p/19q codeletion share prognoses similar to OD, complicating classification.
- Previous studies suggested apparent diffusion coefficient (ADC) from diffusion tensor imaging (DTI) can differentiate AS and OD.
Purpose of the Study:
- To validate a previously established ADC-based criterion for differentiating AS and OD in an independent cohort.
- To investigate the performance of this criterion in mixed oligoastrocytomas (OAs) with varying 1p/19q chromosome status.
- To explore the association between ADC and tumor microstructure, including axonal disruption and tumor cell fraction.
Main Methods:
- Presurgical DTI scans were acquired, and ADC maps were generated.
- ADC colormaps guided targeted biopsies from distinct tumor regions.
- Biopsies were analyzed for SMI-31 (axonal disruption) and tumor cell fraction.
Main Results:
- The median normalized ADC distinguished OD from AS with 91% sensitivity and 92% specificity.
- 1p/19q codeleted OAs were classified as OD, while 1p/19q intact OAs were classified as AS.
- ADC showed positive associations with axonal disruption (SMI-31) and tumor cell fraction, with differing correlations based on glioma subtype.
Conclusions:
- The established ADC threshold effectively differentiates grade II OD and AS in a new cohort, including OAs with different 1p/19q statuses.
- ADC serves as a valuable imaging biomarker for distinguishing these glioma subtypes.
- ADC in grade II gliomas reflects underlying tumor biology, correlating with cellularity and axonal integrity.
