Utilizing Magnetic Resonance Perfusion Imaging to Dectect Tumor Recurrence: A 180 Patient Series

Introduction: Recurrence is inevitable for patients with glioblastoma multiforme (GBM) and many with intracranial metastases. Early detection of tumor progression is critical for effective management and timely secondary treatment. However, distinguishing recurrent tumors (RT) from radiation necrosis (RN) or treatment effects (TE) remains challenging. Magnetic resonance perfusion (MRP) is often employed non-invasively to make this distinction, though its accuracy compared to histologic diagnosis remains debated.

Methods: An institutional retrospective review was conducted on patients with suspected recurrent GBM or metastases between September 2012 and July 2024. Inclusion criteria were: 1) age ≥18 years, 2) MRP performed prior to re-operation, and 3) diagnosis confirmed through histopathology of resected tissue. The sensitivity and specificity of elevated cerebral blood volume (CBV) on MRP, along with MRP-based diagnoses by board-certified neuroradiologists, were analyzed. Diagnostic concordance (κ) between MRP and histologic diagnosis was also evaluated.

Results: A total of 180 patients, with a mean age of 62 years, were included. Elevated CBV on MRP showed sensitivity and specificity of 86.7% and 63.6% for GBM and 42.9% and 78.9% for metastases. MRP-based diagnoses, incorporating all available imaging data, demonstrated higher sensitivity: 90.3% for GBM and 66.7% for metastases. Cohen’s kappa revealed moderate concordance between MRP and histologic diagnosis for GBM (κ=0.45, p< 0.001) but not for metastases (κ=0.01, p=0.91). A significant relationship between MRP accuracy and time-to-biopsy was observed (p < 0.001).

Conclusion : This large study suggests that MRP offers some predictive value in differentiating RT, TE, and RN. However, the clinical utility of MRP before re-operation remains limited, especially for metastases. These findings support the need for direct tissue diagnosis—via resection or stereotactic biopsy—when RT is suspected, to ensure timely, definitive diagnosis and avoid treatment delays.