Metabolic and physiologic magnetic resonance imaging in distinguishing true progression from pseudoprogression in patients with glioblastoma

Abstract

Pseudoprogression (PsP) refers to treatment-related clinico-radiologic changes mimicking true progression (TP) that occurs in patients with glioblastoma (GBM), predominantly within the first 6 months after the completion of surgery and concurrent chemoradiation therapy (CCRT) with temozolomide. Accurate differentiation of TP from PsP is essential for making informed decisions on appropriate therapeutic intervention as well as for prognostication of these patients. Conventional neuroimaging findings are often equivocal in distinguishing between TP and PsP and present a considerable diagnostic dilemma to oncologists and radiologists.These challenges have emphasized the need for developing alternative imaging techniques that may aid in the accurate diagnosis of TP and PsP. In this review, we encapsulate the current state of knowledge in the clinical applications of commonly used metabolic and physiologic magnetic resonance (MR) imaging techniques such as diffusion and perfusion imaging and proton spectroscopy in distinguishing TP from PsP. We also showcase the potential of promising imaging techniques, such as amide proton transfer and amino acid-based positron emission tomography, in providing useful information about the treatment response. Additionally, we highlight the role of "radiomics", which is an emerging field of radiology that has the potential to change the way in which advanced MR techniques are utilized in assessing treatment response in GBM patients. Finally, we present our institutional experiences and discuss future perspectives on the role of multiparametric MR imaging in identifying

Tumor Progression and Treatment-Related Changes: Radiological Diagnosis Challenges for the Evaluation of Post Treated Glioma

“…PsP is predominantly a subacute treatment-related reaction that may or may not involve neurological deterioration [ 4 ]. Radiologically, PsP can be described as new or enlarging areas of contrast enhancement on follow-up MRI within the first 3–6 months of the completion of chemoradiotherapy following surgical resection, which subsides or stabilizes without further intervention treatments, and some studies suggest that PsP may have a relatively good prognosis [ 7 , 8 ]. Various reports have defined the time of PsP occurrence differently, which is likely to affect the incidence.…”

“…The O 6 -methylguanine-DNA methyltransferase (MGMT) status [ 9 ], isocitrate dehydrogenase (IDH) gene status [ 11 ], Ki67 expression [ 12 ], and p53 status [ 13 ] were all associated with PsP occurrence. Tumors with a methylated MGMT promoter and IDH mutation show PsP more frequently and have better median OS [ 7 , 9 ], and a study found a 91.3% probability of PsP in patients with methylated MGMT promoter tumors [ 9 ]. These biomarkers clearly affect PsP incidence and prognosis.…”

Radiomics analysis of amide proton transfer‐weighted and structural MR images for treatment response assessment in malignant gliomas

“…32 Alternatively, radiomics analysis is capable of converting images into quantitative and objective features. Multiple radiomics studies have demonstrated that such quantitative measurements have potential in the diagnosis and subsequent management of patients with gliomas, [33][34][35][36][37][38][39][40][41][42] including APTw-based radiomics studies for the molecular marker identification 43 and differentiation of gliomas from metastases. 44 In addition, researchers are beginning to develop computer-aided diagnostic models for radiomics analysis to assess the treatment response of gliomas.…”

A Comparison of PET Tracers in Recurrent High-Grade Gliomas: A Systematic Review

“…It is believed to be due to factors causing tissue inflammation and the upregulation of vascular endothelial growth factor (VEGF), which lead to increased vessel permeability and edema. Patients exhibiting pseudoprogression show a favorable response to temozolomide chemotherapy treatment [9] and are symptomatically managed along with follow-up CE-MRI scans.…”