Abstract
Differentiating true progression or recurrence (TP/TR) from therapy-related changes (TRC) is complex in brain tumours. Amide proton transfer-weighted (APT) imaging is a chemical exchange saturation transfer (CEST) MRI technique that may improve diagnostic accuracy during radiological follow-up. This systematic review and meta-analysis elucidated the level of evidence and details of state-of-the-art imaging for APT-CEST in glioma and brain metastasis surveillance. PubMed, EMBASE, Web of Science, and Cochrane Library were systematically searched for original articles about glioma and metastasis patients who received APT-CEST imaging for suspected TP/TR within 2 years after (chemo)radiotherapy completion. Modified Quality Assessment of Diagnostic Accuracy Studies-2 criteria were applied. A meta-analysis was performed to pool results and to compare subgroups. Fifteen studies were included for a narrative synthesis, twelve of which (500 patients) were deemed sufficiently homogeneous for a meta-analysis. Magnetisation transfer ratio asymmetry performed well in gliomas (sensitivity 0.88 [0.82-0.92], specificity 0.84 [0.72-0.91]) but not in metastases (sensitivity 0.64 [0.38-0.84], specificity 0.56 [0.33-0.77]). APT-CEST combined with conventional/advanced MRI rendered 0.92 [0.86-0.96] and 0.88 [0.72-0.95] in gliomas. Tumour type, TR prevalence, sex, and acquisition protocol were sources of significant inter-study heterogeneity in sensitivity (I= 62.25%; p < 0.01) and specificity (I= 66.31%; p < 0.001). A growing body of literature suggests that APT-CEST is a promising technique for improving the discrimination of TP/TR from TRC in gliomas, with limited data on metastases. This meta-analysis identified a utility for APT-CEST imaging regarding the non-invasive discrimination of brain tumour progression from therapy-related changes, providing a critical evaluation of sequence parameters and cut-off values, which can be used to improve response assessment and patient outcome. Therapy-related changes mimicking progression complicate brain tumour treatment. Amide proton imaging improves the non-invasive discrimination of glioma progression from therapy-related changes. Magnetisation transfer ratio asymmetry measurement seems not to have added value in brain metastases.
Overview
- The study aims to evaluate the level of evidence and details of state-of-the-art imaging for amide proton transfer-weighted (APT)-CEST in glioma and brain metastasis surveillance. The study uses a systematic review and meta-analysis to compare subgroups and identify the utility of APT-CEST imaging for non-invasively discriminating brain tumor progression from therapy-related changes. The study includes 15 studies with 500 patients who received APT-CEST imaging for suspected true progression or recurrence (TP/TR) within 2 years after (chemo)radiotherapy completion. The study applies modified Quality Assessment of Diagnostic Accuracy Studies-2 criteria and performs a meta-analysis to pool results and compare subgroups. The primary objective of the study is to provide a critical evaluation of sequence parameters and cut-off values that can be used to improve response assessment and patient outcome.
Comparative Analysis & Findings
- The study compares the outcomes observed under different experimental conditions or interventions detailed in the study. The study identifies a growing body of literature suggesting that APT-CEST is a promising technique for improving the discrimination of true progression or recurrence (TP/TR) from therapy-related changes in gliomas, with limited data on metastases. The study finds that magnetisation transfer ratio asymmetry measurement seems not to have added value in brain metastases. The study also identifies a utility for APT-CEST imaging regarding the non-invasive discrimination of glioma progression from therapy-related changes, providing a critical evaluation of sequence parameters and cut-off values, which can be used to improve response assessment and patient outcome.
Implications and Future Directions
- The study's findings suggest that APT-CEST is a promising technique for improving the discrimination of true progression or recurrence (TP/TR) from therapy-related changes in gliomas, with limited data on metastases. The study identifies a utility for APT-CEST imaging regarding the non-invasive discrimination of glioma progression from therapy-related changes, providing a critical evaluation of sequence parameters and cut-off values, which can be used to improve response assessment and patient outcome. The study also identifies sources of significant inter-study heterogeneity in sensitivity and specificity, such as tumor type, TR prevalence, sex, and acquisition protocol. Future research should address these sources of heterogeneity and explore the utility of APT-CEST imaging in other brain tumor types and metastatic sites. The study also suggests that APT-CEST imaging can be used to improve response assessment and patient outcome, and future research should investigate the impact of APT-CEST imaging on patient outcomes, such as survival and quality of life.