Predictive value of multimodality MRI using conventional, perfusion, and spectroscopy MR in anaplastic transformation
Chadi Hlaihel1, Laurent Guilloton, Jacques Guyotat
1Department of Radiology, Hospital Lyon Sud, Université de Lyon, Université Lyon 1, Hospices civils de Lyon, Pierre-Benite, France. chadi.hlaihel@gmail.com
Abstract:
The aim of our study was to evaluate the role of proton magnetic resonance (MR) spectroscopy and MR perfusion in the follow-up of low-grade gliomas, since conventional MR imaging (MRI) is not reliable in detecting the passage from a low- to high-grade tumor. Twenty-one patients with a World Health Organisation (WHO) grade II glioma were followed up using proton MR spectroscopy, perfusion, and conventional MRIs. Follow-up MRIs had been performed at the third month of evolution and then twice a year, with an average of five MR studies per patient. Five out of the 21 patients had an anaplastic transformation. A choline to creatine ratio (choline/creatine ratio) above 2.4 is associated with an 83% risk of a malignant transformation in an average delay of 15.4 months. The choline/creatine ratio at this threshold was more efficient than perfusion MR in detecting the anaplastic transformation, with sensitivity of 80% and specificity of 94%. An increased choline/creatine ratio seemed to occur an average 15 months before the elevation of relative cerebral blood volume (rCBV). The mean annual growth of low-grade glioma was 3.65 mm. A growth rate higher than 3 mm per year was also correlated with greater risk of anaplastic transformation. Proton magnetic resonance spectroscopy should be recommended in the follow-up of low-grade gliomas since the choline/creatine ratio can predict anaplastic transformation before perfusion abnormalities, with high positive predictive value of 83%.
Insights
Proton MR spectroscopy can predict malignant transformation in low-grade gliomas. A high choline/creatine ratio indicates an 83% risk, preceding perfusion changes by 15 months.
Area of Science:
- Neuro-oncology
- Radiology
- Medical Imaging
Background:
- Conventional MRI is insufficient for detecting low- to high-grade glioma progression.
- Low-grade gliomas require reliable monitoring for malignant transformation.
Purpose of the Study:
- To assess the utility of proton MR spectroscopy and MR perfusion in monitoring World Health Organization (WHO) grade II gliomas.
- To identify imaging biomarkers for predicting anaplastic transformation in low-grade gliomas.
Main Methods:
- Follow-up of 21 WHO grade II glioma patients using conventional MRI, proton MR spectroscopy, and MR perfusion.
- Analysis of choline/creatine ratio and relative cerebral blood volume (rCBV) changes.
- Correlation of imaging findings with tumor progression and anaplastic transformation.
Main Results:
- Five of 21 patients experienced anaplastic transformation.
- A choline/creatine ratio > 2.4 predicted malignant transformation with 83% risk at 15.4 months.
- Choline/creatine ratio detected transformation earlier than perfusion (15 months prior to rCBV elevation).
- Tumor growth rate > 3 mm/year also correlated with increased transformation risk.
Conclusions:
- Proton MR spectroscopy, specifically the choline/creatine ratio, is a valuable tool for predicting anaplastic transformation in low-grade gliomas.
- This technique offers high sensitivity and specificity, outperforming perfusion MR in early detection.
- Routine use of proton MR spectroscopy is recommended for improved glioma follow-up and management.
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