Imaging modalities in high-grade gliomas: pseudoprogression, recurrence, or necrosis?

Area of Science:

• Neuro-oncology
• Radiology
• Nuclear Medicine

Background:

• High-grade gliomas (HGG) often recur post-treatment, posing diagnostic challenges.
• Therapy-induced changes like pseudoprogression (PP) and radiation necrosis (RN) can mimic progressive disease (PD) on imaging.
• Accurate differentiation is crucial for appropriate patient management.

Purpose of the Study:

• To review existing literature on imaging modalities for differentiating HGG progressive disease (PD) from pseudoprogression (PP) and radiation necrosis (RN).
• To assess the sensitivity and specificity of various imaging techniques in this differentiation.

Main Methods:

• A comprehensive literature review was conducted, analyzing 26 articles.
• Studies compared the diagnostic value of different imaging modalities, including MRI, PET, and SPECT.

Main Results:

• Conventional MRI and (18)fluorine-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) demonstrated higher sensitivity in differentiating PD from PP and RN.
• (18)F-FDG PET showed promise in detecting metabolic changes associated with tumor activity.
• Thallium single photon emission CT (SPECT) exhibited greater specificity in distinguishing PD from PP and RN.

Conclusions:

• Both MRI and (18)F-FDG PET are sensitive tools for detecting potential HGG progression.
• Thallium SPECT provides higher specificity for differentiating true progression from treatment effects.
• Further prospective studies are essential to determine the optimal diagnostic imaging strategy for HGG recurrence.