The value of arterial spin labelling in adults glioma grading: systematic review and meta-analysis

Abstract

This study aimed to evaluate the diagnostic performance of arterial spin labelling (ASL) in grading of adult gliomas. Eighteen studies matched the inclusion criteria and were included after systematic searches through EMBASE and MEDLINE databases. The quality of the included studies was assessed utilizing Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2). The quantitative values were extracted and a meta-analysis was subsequently based on a random-effect model with forest plot and joint sensitivity and specificity modelling. Hierarchical summary receiver operating characteristic (HROC) curve analysis was also conducted. The absolute tumour blood flow (TBF) values can differentiate high-grade gliomas (HGGs) from low-grade gliomas (LGGs) and grade II from grade IV tumours. However, it lacked the capacity to differentiate grade II from grade III tumours and grade III from grade IV tumours. In contrast, the relative TBF (rTBF) is effective in differentiating HGG from LGG and in glioma grading. The maximum rTBF (rTBFmax) demonstrated the best results in glioma grading. These results were also reflected in the sensitivity/specificity analysis in which the rTBFmax showed the highest discrimination performance in glioma grading. The estimated effect size for the rTBF was approximately similar between HGGs and LGGs, and grade II and grade III tumours, (-1.46 (-2.00, -0.91), p-value < 0.001), (-1.39 (-1.89, -0.89), p-value < 0.001), respectively; while it exhibited smaller effect size between grade III and grade IV (-1.05 (-1.82, -0.27)), p < 0.05). Sensitivity and specificity analysis replicate these results as well. This meta-analysis suggests that ASL is useful for glioma grading, especially when considering the rTBFmax parameter.

Keywords: arterial spin labeling; glioma; grading.

Figure 1. Preferred Reporting Items of Systematic Reviews and Meta-Analyses-PRISMA flow chart for the study selection process

Figure 2. The Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) results for the included studies

Figure 3. HROC plot of the summary point of the sensitivity and the specificity (square) and its 95% CI (the green curve) of rTBF from ASL to differentiate between

(A) grade II and grade III (94%, CI (75%, 99%)) and (61%, CI (48%, 73%)), respectively; (B) grade III and grade IV (86%, CI (75%, 93%)) and (69%, CI (57%, 79%)), respectively.

Figure 4. HROC plot shows the summary point of the sensitivity and the specificity (square) and its 95% CI (the green curve)

(A) from all of the analysed ASL parameters to differentiate between HGGs and LGGs (86%, CI (78%, 91%)) and (84%, CI (76%, 90%)), respectively; (B) rTBF to differentiate between HGGs and LGGs (86%, CI (77%, 91%)) and (84%, CI (76%, 90%)), respectively; (C) rTBFmean to differentiate between HGGs and LGGs (84%, CI (71%, 92%)) and (79%, CI (66%, 88%), respectively; (D) rTBFmax to differentiate between HGGs and LGGs (85%, CI (69%, 94%)) and (92%, CI (80%, 97%)).