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Role of FDG-PET/MRI, FDG-PET/CT, and Dynamic Susceptibility Contrast Perfusion MRI in Differentiating Radiation
Mojgan Hojjati1, Chaitra Badve1, Vasant Garg1
1Department of Radiology, University Hospitals Cleveland Medical Center, Cleveland, OH.
Background And Purpose:
To compare the utility of quantitative PET/MRI, dynamic susceptibility contrast (DSC) perfusion MRI (pMRI), and PET/CT in differentiating radiation necrosis (RN) from tumor recurrence (TR) in patients with treated glioblastoma multiforme (GBM).
Methods:
The study included 24 patients with GBM treated with surgery, radiotherapy, and temozolomide who presented with progression on imaging follow-up. All patients underwent PET/MRI and pMRI during a single examination. Additionally, 19 of 24 patients underwent PET/CT on the same day. Diagnosis was established by pathology in 17 of 24 and by clinical/radiologic consensus in 7 of 24. For the quantitative PET/MRI and PET/CT analysis, a region of interest (ROI) was drawn around each lesion and within the contralateral white matter. Lesion to contralateral white matter ratios for relative maximum, mean, and median were calculated. For pMRI, lesion ROI was drawn on the cerebral blood volume (CBV) maps and histogram metrics were calculated. Diagnostic performance for each metric was assessed using receiver operating characteristic curve analysis and area under curve (AUC) was calculated.
Results:
In 24 patients, 28 lesions were identified. For PET/MRI, relative mean ≥ 1.31 resulted in AUC of .94 with both sensitivity and negative predictive values (NPVs) of 100%. For pMRI, CBV max ≥3.32 yielded an AUC of .94 with both sensitivity and NPV measuring 100%. The joint model utilizing r-mean (PET/MRI) and CBV mode (pMRI) resulted in AUC of 1.0.
Conclusion:
Our study demonstrates that quantitative PET/MRI parameters in combination with DSC pMRI provide the best diagnostic utility in distinguishing RN from TR in treated GBMs.
Insights
Quantitative PET/MRI and perfusion MRI (pMRI) effectively differentiate radiation necrosis from tumor recurrence in treated glioblastoma. Combining these imaging techniques offers the highest diagnostic accuracy for these challenging cases.
Area of Science:
- Neuro-oncology
- Radiology
- Medical Imaging
Background:
- Distinguishing radiation necrosis (RN) from tumor recurrence (TR) is critical in treated glioblastoma multiforme (GBM).
- Standard imaging follow-up can be challenging in identifying these conditions accurately.
- Novel imaging techniques are needed to improve diagnostic precision.
Purpose of the Study:
- To compare the diagnostic utility of quantitative PET/MRI, dynamic susceptibility contrast perfusion MRI (DSC pMRI), and PET/CT.
- To differentiate radiation necrosis from tumor recurrence in patients with treated GBM.
- To evaluate the performance of quantitative imaging metrics in this differentiation.
Main Methods:
- 24 GBM patients with suspected RN or TR underwent quantitative PET/MRI and DSC pMRI.
- 19 patients also underwent PET/CT.
- Analysis involved calculating lesion-to-white matter ratios for PET and histogram metrics for pMRI, followed by ROC analysis.
Main Results:
- Quantitative PET/MRI (relative mean ≥ 1.31) and DSC pMRI (CBV max ≥ 3.32) showed high diagnostic performance (AUC .94) with 100% sensitivity and NPV.
- A combined model using PET/MRI and pMRI metrics achieved a perfect AUC of 1.0.
- 28 lesions were analyzed across 24 patients.
Conclusions:
- Quantitative PET/MRI parameters combined with DSC pMRI offer superior diagnostic utility for differentiating RN from TR in treated GBM.
- This multimodal imaging approach enhances diagnostic accuracy in challenging post-treatment scenarios.
- The findings support the integration of these advanced imaging techniques in GBM follow-up.
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