Advanced multimodal imaging in differentiating glioma recurrence from post-radiotherapy changes

Beyond conventional imaging: Advancements in MRI for glioma malignancy prediction and molecular profiling

This review examines the advancements in magnetic resonance imaging (MRI) techniques and their pivotal role in diagnosing and managing gliomas, the most prevalent primary brain tumors. The paper underscores the importance of integrating modern MRI modalities, such as diffusion-weighted imaging and perfusion MRI, which are essential for assessing glioma malignancy and predicting tumor behavior. Special attention is given to the 2021 WHO Classification of Tumors of the Central Nervous System, emphasizing the integration of molecular diagnostics in glioma classification, significantly impacting treatment decisions. The review also explores radiogenomics, which correlates imaging features with molecular markers to tailor personalized treatment strategies. Despite technological progress, MRI protocol standardization and result interpretation challenges persist, affecting diagnostic consistency across different settings. Furthermore, the review addresses MRI's capacity to distinguish between tumor recurrence and pseudoprogression, which is vital for patient management. The necessity for greater standardization and collaborative research to harness MRI's full potential in glioma diagnosis and personalized therapy is highlighted, advocating for an enhanced understanding of glioma biology and more effective treatment approaches.

Amide proton transfer-weighted and arterial spin labeling imaging may improve differentiation between high-grade glioma recurrence and radiation-induced brain injury

Rationale and objectives

The management of tumor recurrence (TR) and radiation-induced brain injury (RIBI) poses significant challenges, necessitating the development of effective differentiation strategies. In this study, we investigated the potential of amide proton transfer-weighted (APTw) and arterial spin labeling (ASL) imaging for discriminating between TR and RIBI in patients with high-grade glioma (HGG).

Methods

A total of 64 HGG patients receiving standard treatment were enrolled in this study. The patients were categorized based on secondary pathology or MRI follow-up results, and the demographic characteristics of each group were presented. The APTw, rAPTw, cerebral blood flow (CBF) and rCBF values were quantified. The differences in various parameters between TR and RIBI were assessed using the independent-samples t-test. The discriminative performance of these MRI parameters in distinguishing between the two conditions was assessed using receiver operating characteristic (ROC) curve analysis. Additionally, the Delong test was employed to further evaluate their discriminatory ability.

Results

The APTw and CBF values of TR were significantly higher compared to RIBI (P < 0.05). APTw MRI demonstrated superior diagnostic efficiency in distinguishing TR from RIBI (area under the curve [AUC]: 0.864; sensitivity: 75.0 %; specificity: 81.8 %) when compared to ASL imaging. The combined utilization of APTw and CBF value further enhanced the AUC to 0.922. The Delong test demonstrated that the combination of APTw and ASL exhibited superior performance in the identification of TR and RIBI, compared to ASL alone (P = 0.048).

Conclusion

APTw exhibited superior diagnostic efficacy compared to ASL in the evaluation of TR and RIBI. Furthermore, the combination of APTw and ASL exhibits greater discriminatory capability and diagnostic performance.

Texture Analysis of the Apparent Diffusion Coefficient Focused on Contrast-Enhancing Lesions in Predicting Survival for Bevacizumab-Treated Patients with Recurrent Glioblastoma

PURPOSE

Glioblastoma often recurs after treatment. Bevacizumab increases progression-free survival in some patients with recurrent glioblastoma. Identifying pretreatment predictors of survival can help clinical decision making. Magnetic resonance texture analysis (MRTA) quantifies macroscopic tissue heterogeneity indirectly linked to microscopic tissue properties. We investigated the usefulness of MRTA in predicting survival in patients with recurrent glioblastoma treated with bevacizumab.

METHODS

We evaluated retrospective longitudinal data from 33 patients (20 men; mean age 56 ± 13 years) who received bevacizumab on the first recurrence of glioblastoma. Volumes of contrast-enhancing lesions segmented on postcontrast T1-weighted sequences were co-registered on apparent diffusion coefficient maps to extract 107 radiomic features. To assess the performance of textural parameters in predicting progression-free survival and overall survival, we used receiver operating characteristic curves, univariate and multivariate regression analysis, and Kaplan-Meier plots.

RESULTS

Longer progression-free survival (>6 months) and overall survival (>1 year) were associated with lower values of major axis length (MAL), a lower maximum 2D diameter row (m2Ddr), and higher skewness values. Longer progression-free survival was also associated with higher kurtosis, and longer overall survival with higher elongation values. The model combining MAL, m2Ddr, and skewness best predicted progression-free survival at 6 months (AUC 0.886, 100% sensitivity, 77.8% specificity, 50% PPV, 100% NPV), and the model combining m2Ddr, elongation, and skewness best predicted overall survival (AUC 0.895, 83.3% sensitivity, 85.2% specificity, 55.6% PPV, 95.8% NPV).

CONCLUSIONS

Our preliminary analyses suggest that in patients with recurrent glioblastoma pretreatment, MRTA helps to predict survival after bevacizumab treatment.

Diagnostic value of PET with different radiotracers and MRI for recurrent glioma: a Bayesian network meta-analysis

OBJECTIVE

The purpose of this study was to evaluate the diagnostic accuracy of 6 different imaging modalities for differentiating glioma recurrence from postradiotherapy changes by performing a network meta-analysis (NMA) using direct comparison studies with 2 or more imaging techniques.

DATA SOURCES

PubMed, Scopus, EMBASE, the Web of Science and the Cochrane Library were searched from inception to August 2021. The Confidence In Network Meta-Analysis (CINeMA) tool was used to evaluate the quality of the included studies with the criterion for study inclusion being direct comparison using 2 or more imaging modalities.

DATA EXTRACTION AND SYNTHESIS

The consistency was evaluated by examining the agreement between direct and indirect effects. NMA was performed and the surface under the the cumulative ranking curve (SUCRA) values was obtained to calculate the probability of each imaging modality being the most effective diagnostic method. The CINeMA tool was used to evaluate the quality of the included studies.

MAIN OUTCOMES AND MEASURES

Direct comparison, inconsistency test, NMA and SUCRA values.

RESULTS

A total of 8853 potentially relevant articles were retrieved and 15 articles met the inclusion criteria. 18F-FET showed the highest SUCRA values for sensitivity, specificity, positive predictive value and accuracy, followed by 18F-FDOPA. The quality of the included evidence is classified as moderate.

CONCLUSION AND RELEVANCE

This review indicates that 18F-FET and 18F-FDOPA may have greater diagnostic value for glioma recurrence relative to other imaging modalities (Grading of Recommendations, Assessment, Development and Evaluations B).

PROSPERO REGISTRATION NUMBER

CRD42021293075.

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

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 PsP in GBM patients treated with "standard-of-care" CCRT as well as novel/targeted therapies.

Regorafenib in Glioblastoma Recurrence: How to Deal With MR Imaging Treatments Changes

The treatment of recurrent high-grade gliomas remains a major challenge of daily neuro-oncology practice, and imaging findings of new therapies may be challenging. Regorafenib is a multi-kinase inhibitor that has recently been introduced into clinical practice to treat recurrent glioblastoma, bringing with it a novel panel of MRI imaging findings. On the basis of the few data in the literature and on our personal experience, we have identified the main MRI changes during regorafenib therapy, and then, we defined two different patterns, trying to create a simple summary line of the main changes of pathological tissue during therapy. We named these patterns, respectively, pattern A (less frequent, similar to classical progression disease) and pattern B (more frequent, with decreased diffusivity and decrease contrast-enhancement). We have also reported MR changes concerning signal intensity on T1-weighted and T2-weighted images, SWI, and perfusion imaging, derived from the literature (small series or case reports) and from our clinical experience. The clinical implication of these imaging modifications remains to be defined, taking into account that we are still at the dawn in the evaluation of such imaging modifications.

Advanced Imaging Techniques for Newly Diagnosed and Recurrent Gliomas

Management of gliomas following initial diagnosis requires thoughtful presurgical planning followed by regular imaging to monitor treatment response and survey for new tumor growth. Traditional MR imaging modalities such as T1 post-contrast and T2-weighted sequences have long been a staple of tumor diagnosis, surgical planning, and post-treatment surveillance. While these sequences remain integral in the management of gliomas, advances in imaging techniques have allowed for a more detailed characterization of tumor characteristics. Advanced MR sequences such as perfusion, diffusion, and susceptibility weighted imaging, as well as PET scans have emerged as valuable tools to inform clinical decision making and provide a non-invasive way to help distinguish between tumor recurrence and pseudoprogression. Furthermore, these advances in imaging have extended to the operating room and assist in making surgical resections safer. Nevertheless, surgery, chemotherapy, and radiation treatment continue to make the interpretation of MR changes difficult for glioma patients. As analytics and machine learning techniques improve, radiomics offers the potential to be more quantitative and personalized in the interpretation of imaging data for gliomas. In this review, we describe the role of these newer imaging modalities during the different stages of management for patients with gliomas, focusing on the pre-operative, post-operative, and surveillance periods. Finally, we discuss radiomics as a means of promoting personalized patient care in the future.

Targeted therapy with anlotinib for a leptomeningeal spread recurrent glioblastoma patient

Glioblastoma (GBM) is the most common and the most aggressive primary malignant brain tumor in adults. Although tumor recurrence is inevitable, leptomeningeal spread is relatively rare. We describe a case of leptomeningeal spread recurrent GBM treated with anlotinib in this report. When the recurrent GBM patient had leptomeningeal spread was administered anlotinib 10mg p.o. once every day and added oral temozolomide chemotherapy 100mg/m² (days 1-7, days 15-21, 28-day cycle) after 3 months. The patient's overall survival time was more than 5 months and developed oral ulcer and acute cerebral infarction during his oral administration of anlotinib. This patient showed a favorable clinic outcome for treatment of leptomeningeal spread recurrent GBM with anlotinib and didn't show serious side effects.

Multimodal imaging in the differential diagnosis of glioma recurrence from treatment-related effects: A protocol for systematic review and network meta-analysis

BACKGROUND

Glioma is the most common malignant primary brain tumor and it will always recur. To date, various multimodal imaging including magnetic resonance imaging (MRI) and positron emission tomography computed tomography (PET/CT) was used to differentiate the diagnosis of true tumor recurrent (TuR) and treatment-related effects (TrE) in glioma patient but with no overall conclusion. In this study, SROC curve and Bayesian network meta-analysis will be used to conduct a comprehensive analysis of the results of different clinical reports, and assess the efficacy of multimodal imaging in difference TuR and TrE.

METHODS

To find more comprehensive information about the application of multimodal imaging in glioma patients, we searched the EMBASE, Pubmed, and Cochrane Central Register of Controlled Trials for relevant clinical trials. We also reviewed their reference lists to avoid omissions. QUADAS-2, RevMan software, Stata, and R software will be used.

RESULTS

This study will provide reliable evidence for the efficacy of multimodal imaging in the differential diagnosis of TuR and TrE in glioma patients.

CONCLUSION

We will evaluate the effectiveness of different and rank each imaging method in glioma patients to provide a decision-making reference on which method to choose for clinicians. Protocol registration number: CRD42020217861.

Identify glioma recurrence and treatment effects with triple-tracer PET/CT

Background

Differential diagnosis of tumour recurrence (TuR) from treatment effects (TrE), mostly induced by radiotherapy and chemotherapy, is still difficult by using conventional computed tomography (CT) or magnetic resonance (MR) imaging. We have investigated the diagnostic performance of PET/CT with 3 tracers, ¹³N-NH₃, ¹⁸F-FDOPA, and ¹⁸F-FDG, to identify TuR and TrE in glioma patients following treatment.

Methods

Forty-three patients with MR-suspected recurrent glioma were included. The maximum and mean standardized uptake values (SUVmax and SUVmean) of the lesion and the lesion-to-normal grey-matter cortex uptake (L/G) ratio were obtained from each tracer PET/CT. TuR or TrE was determined by histopathology or clinical MR follow-up for at least 6 months.

Results

In this cohort, 34 patients were confirmed to have TuR, and 9 patients met the diagnostic standard of TrE. The SUVmax and SUVmean of ¹³N-NH₃ and ¹⁸F-FDOPA PET/CT at TuR lesions were significantly higher compared with normal brain tissue (¹³N-NH₃ 0.696 ± 0.558, 0.625 ± 0.507 vs 0.486 ± 0.413; ¹⁸F-FDOPA 0.455 ± 0.518, 0.415 ± 0.477 vs 0.194 ± 0.203; both P < 0.01), but there was no significant difference in ¹⁸F-FDG (6.918 ± 3.190, 6.016 ± 2.807 vs 6.356 ± 3.104, P = 0.290 and 0.493). L/G ratios of ¹³N-NH₃ and ¹⁸F-FDOPA were significantly higher in TuR than in TrE group (¹³N-NH_3, 1.573 ± 0.099 vs 1.025 ± 0.128, P = 0.008; ¹⁸F-FDOPA, 2.729 ± 0.131 vs 1.514 ± 0.141, P < 0.001). The sensitivity, specificity and AUC (area under the curve) by ROC (receiver operating characteristic) analysis were 57.7%, 100% and 0.803, for ¹³N-NH₃; 84.6%, 100% and 0.938, for ¹⁸F-FDOPA; and 80.8%, 100%, and 0.952, for the combination, respectively.

Conclusion

Our results suggest that although multiple tracer PET/CT may improve differential diagnosis efficacy, for glioma TuR from TrE, ¹⁸F-FDOPA PET-CT is the most reliable. The combination of ¹⁸F-FDOPA and ¹³N-NH₃ does not increase the diagnostic efficiency, while ¹⁸F-FDG is not worthy for differential diagnosis of glioma TuR and TrE.

Multimodal MRI Assessment of Thalamic Structural Changes in Earthquake Survivors

Moving from the central role of the thalamus in the integration of inner and external stimuli and in the implementation of a stress-related response, the objective of the present study was to investigate the presence of any MRI structural and volumetric changes of the thalamic structures in earthquake witnesses. Forty-one subjects were included, namely 18 university students belonging to the experimental earthquake-exposed group (8 males and 10 females, mean age 24.5 ± 1.8 years) and a control group of 23 students not living in any earthquake-affected areas at the time of the earthquake (14 males and 9 females, mean age 23.7 ± 2.0 years). Instrumental MRI evaluation was performed using a 3-Tesla scanner, by acquiring a three-dimensional fast spoiled gradient-echo (FSPGR) sequence for volumetric analysis and an EPI (echoplanar imaging) sequence to extract fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values. As compared to the control one, the experimental group showed significantly lower gray matter volume in the mediodorsal nucleus of the left thalamus (p < 0.001). The dominant hemisphere thalamus in the experimental group showed higher mean ADC values and lower mean FA values as compared to the control group.