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Updated: Jan 4, 2026
Diffusion Tensor Magnetic Resonance Imaging in the Analysis of Neurodegenerative Diseases
Published on: July 28, 2013
Differentiation of pilocytic and pilomyxoid astrocytomas using dynamic susceptibility contrast perfusion and
Chang Y Ho1, Nucharin Supakul2, Parth U Patel3
1Department of Radiology and Imaging Sciences, MRI Department, Indiana University School of Medicine, 705 Riley Hospital Drive, Indianapolis, IN, 46202, USA. cyho@iupui.edu.
Insights
Dynamic susceptibility contrast (DSC) perfusion and diffusion MRI can help differentiate pilomyxoid astrocytomas (PMA) from pilocytic astrocytomas (PA) in children. PMA shows higher rCBV in the infratentorial space, aiding in diagnosis.
Area of Science:
- Pediatric neuro-oncology
- Neuroradiology
- Quantitative MRI
Background:
- Pilocytic astrocytoma (PA) and pilomyxoid astrocytoma (PMA) are low-grade pediatric brain tumors.
- While sharing similar imaging, PMA presents a worse prognosis and supratentorial predilection in younger children.
- Distinguishing between PA and PMA is crucial for appropriate management.
Purpose of the Study:
- To evaluate quantitative MRI techniques, specifically dynamic susceptibility contrast (DSC) perfusion and diffusion-weighted imaging (DWI), for differentiating PA and PMA.
- To assess for significant differences in imaging characteristics between these two tumor types and their locations (supratentorial vs. infratentorial).
Main Methods:
- Retrospective analysis of pediatric patients with pathology-proven PA and PMA who underwent MRI with DSC and DWI.
- Manual segmentation of tumors on anatomic images registered to rCBV, K2, and ADC maps.
- Comparison of mean values between tumor groups and locations using Student's t test, ROC analysis, and histogram evaluation.
Main Results:
- Analysis of 49 patients revealed significantly increased relative Cerebral Blood Volume (rCBV) in infratentorial PMA compared to PA (2.39 vs. 1.39, p=0.0006).
- Receiver Operating Characteristic (ROC) analysis showed an Area Under the Curve (AUC) of 0.87 for differentiating infratentorial PA from PMA (p<0.001).
- Histogram analysis indicated a higher ADC peak location for PMA (1.8) versus PA (1.56).
Conclusions:
- PMA exhibits significantly higher rCBV than PA within the infratentorial compartment.
- DSC perfusion and DWI MRI are valuable tools for distinguishing between PMA and PA in the infratentorial location.
Purpose:
Pilocytic (PA) and pilomyxoid astrocytomas (PMA) are related low-grade tumors which occur predominantly in children. PMAs have a predilection for a supratentorial location in younger children with worse outcomes. However, the two have similar imaging characteristics. Quantitative MR sequences such as dynamic susceptibility contrast (DSC) perfusion and diffusion (DWI) were assessed for significant differences between the two tumor types and locations.
Methods:
A retrospective search for MRI with DSC and DWI on pathology-proven cases of PMA and PA in children was performed. Tumors were manually segmented on anatomic images registered to rCBV, K2, and ADC maps. Tumors were categorized as PA or PMA, with subclassification of supratentorial and infratentorial locations. Mean values were obtained for tumor groups and locations compared with Student's t test for significant differences with post hoc correction for multiple comparisons. ROC analysis for significant t test values was performed. Histogram evaluation was also performed.
Results:
A total of 49 patients met inclusion criteria. This included 30 patients with infratentorial PA, 8 with supratentorial PA, 6 with supratentorial PMA, and 5 with infratentorial PMA. Mean analysis showed significantly increased rCBV for infratentorial PMA (2.39 ± 1.1) vs PA (1.39 ± 0.16, p = 0.0006). ROC analysis for infratentorial PA vs PMA yielded AUC = 0.87 (p < 0.001). Histogram analysis also demonstrated a higher ADC peak location for PMA (1.8 ± 0.2) vs PA (1.56 ± 0.28).
Conclusion:
PMA has a significantly higher rCBV than PA in the infratentorial space. DSC perfusion and diffusion MR imaging may be helpful to distinguish between the two tumor types in this location.
