Arterial spin labeling in the grading of brain gliomas: could it help?

Abstract

Background Gliomas are characterized by high morbidity and mortality with low cure and high recurrence rates, which depends to a great degree on the angiogenesis of the tumor. Assessment of such angiogenesis by perfusion techniques is of utmost importance for the preoperative grading of gliomas. The purpose of this study was to assess the role of arterial spin labeling (ASL) perfusion as a non-contrast MRI technique in the grading of brain gliomas, in correlation with the dynamic susceptibility contrast perfusion imaging (DSC-PI). The study was carried out on 35 patients admitted to the Neurosurgery Department with MRI features of gliomas and sent for further perfusion imaging. Non-contrast ASL followed by DSC-PI was done for all cases. The final diagnosis of the cases was established by histopathology. Results Fourteen patients (14/35) had low-grade gliomas while twenty-one (21/35) had high-grade gliomas. In low-grade gliomas, four cases out of 14 were falsely graded as high-grade tumors showing hyperperfusion on ASL, three of which showed DSC-PI hypoperfusion. In high-grade gliomas, two cases out of 21 were interpreted as an indeterminate grade by ASL showing isoperfusion, however showed hyperperfusion on DSC-PI. ROC curve analysis showed ASL-derived rCBF > 2.08 to have 80.95% sensitivity, 85.71% specificity, and overall accuracy of 82.86% compared to 100% sensitivity, specificity, and accuracy of DSC-PI-derived rCBV and rCBF of > 1.1 and > 0.9, respectively. A significant positive correlation was noted between ASL and DSC-PI with correlation coefficient reaching r = 0.80 between ASL-rCBF and DSC-rCBF (p < 0.01) and r = 0.68 between ASL and DSC-rCBV (p < 0.01). Conclusions ASL is a relatively recent non-contrast perfusion technique that obtains results which are in fair agreement with the more established DSC perfusion imaging making it an alternative method for preoperative assessment of perfusion of gliomas, especially for patients with contraindications to contrast agents.

Advanced Magnetic Resonance Imaging in Pediatric Glioblastomas

“…In another meta-analysis, although not only composed of gliomas, normalized cerebral blood flow derived from ASL perfusion had 83% accuracy in separating low and high-grade pediatric brain tumors (111). Other authors have also confirmed that ASL can be a potentially valuable tool to differentiate low from high-grade tumors (106,(111)(112)(113)(114) and that the technique has comparable results with DSC in the differentiation between low and HGGs (115).…”

Clinical utility of intraoperative arterial spin labeling for resection control in brain tumor surgery at 3 T

“…Finally, the maximum value of tumor ROI was divided by the mean value of contralateral normal gray matter ROI to estimate CBF ratios 29,38,39 …”

“…If the delay time is sufficiently long for the water spins to reach the capillary bed or tissue, ASL signal is directly proportional to CBF, and absolute CBF measurements can be calculated. Studies have shown the role of ASL in neuro‐oncology for the diagnosis, grading and therapy monitoring of gliomas, with results comparable to those of conventional DSC 25–29 . However, the potential of ASL to assist in the intraoperative setting has been scarcely explored.…”

“…Studies have shown the role of ASL in neuro-oncology for the diagnosis, grading and therapy monitoring of gliomas, with results comparable to those of conventional DSC. [25][26][27][28][29] However, the potential of ASL to assist in the intraoperative setting has been scarcely explored. Two studies including small patient cohorts and performed at the same site have been reported, with results suggesting that intraoperative ASL is feasible at 1.5 T and could provide useful information for resection control.…”

Transformational Role of Medical Imaging in (Radiation) Oncology

“…Various studies have been conducted to evaluate the role of ASL derived tumour blood flow for both tumour grading/differentiation and treatment response with some promising results [ 42 , 43 , 44 , 45 , 46 ]. Some authors have suggested that ASL may be more sensitive in distinguishing tumour recurrence and pseudoprogression than other, more invasive techniques [ 44 , 47 ].…”