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

Abstract

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.

Keywords: APTw; ASL; High-grade glioma; Radiation-induced brain injury; Tumor recurrence.

Fig. 1

The findings were observed in a 58-year-old patient with typical TR. The multiparametric MR images, including T2WI (a), Gd-enhanced T1WI (b), CBF (c), and APTw (d) maps, demonstrate a lesion in the left temporal lobe with significantly heterogeneous enhancement. Importantly, this enhancing lesion is characterized by remarkably high and red signal intensities on both CBF and APTw maps. The EA, PHA, and CNWMA were divided into six equal-sized ROIs. These ROIs were then overlaid onto the CBF and APTw maps to calculate the mean CBF and APTw values for each region. The average CBF values in TR lesion of the left temporal lobe were as follows: 58.64 mL/100 g/min for EA, 27.93 mL/100 g/min for PHA, and 24.75 mL/100 g/min for CNWMA. The average APTw values in TR lesion were as follows: 4.08 % for EA, 2.63 % for PHA, and 1.64 % for CNWMA.

Fig. 2

The findings were observed in a 57-year-old patient with typical RIBI. Multi-parameter MR images, including T2WI (a), Gd-enhanced T1WI (b), CBF (c), and APTw (d), revealed heterogeneous enhanced lesions in the left frontal lobe. The lesions exhibited predominantly green isoperfusion on the CBF maps and scattered flaky yellow signals slightly higher than background on the APTw maps. The EA, PHA, and CNWMA were divided into six equal-sized ROIs. These ROIs were then overlaid onto the CBF and APTw maps to calculate the mean CBF and APTw values for each region. The average CBF values in RIBI lesion were as follows: 32.06 mL/100 g/min for EA, 16.28 mL/100 g/min for PHA, and 15.47 mL/100 g/min for CNWMA. The average APTw values in RIBI lesion were as follows: 2.83 % for EA, 2.23 % for PHA, and 1.81 % for CNWMA.

Fig. 3

Comparisons of parameters in the EA and PHA between TR and RIBI. EA: enhanced area; PHA: peritumoral T2WI hyperintense area; TR: tumor recurrence; RIBI: radiation-induced brain injury.

Fig. 4

The ROC curve for discriminating between TR and RIBI based on APTw and ASL imaging in the EA and PHA. EA: enhanced area; PHA: peritumoral T2WI hyperintense area; TR: tumor recurrence; RIBI: radiation-induced brain injury; CI: confidence interval.

Fig. 5

The relationship between CBF and APTw in the enhanced area was investigated. The CBF and rCBF demonstrated a significant positive correlation with APTw and rAPTw (R = 0.49, R = 0.27, R = 0.37 and R = 0.45), respectively. *** means P < 0.001,** means P < 0.01,* means P < 0.05.