Diagnostic Accuracy of Arterial Spin-Labeling MR Imaging in Detecting the Epileptogenic Zone: Systematic Review and Meta-analysis

Abstract

BACKGROUND: A noninvasive, safe, and economic imaging technique is required to identify epileptogenic lesions in the brain. PURPOSE: Our aim was to perform a meta-analysis evaluating the accuracy of arterial spin-labeling in localizing the epileptic focus in the brain and the changes in the blood perfusion in these regions.DATA SOURCES: Our sources were the PubMed and EMBASE data bases. STUDY SELECTION:English language studies that assessed the diagnostic accuracy of arterial spin-labeling for detecting the epileptogenic zone up to July 2019 were included. DATA ANALYSIS:The symptomatogenic foci of seizures in the brain were determined and used as the references. The relevant studies were evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. The outcomes were evaluated using the pooled sensitivity, pooled specificity, pooled accuracy, diagnostic odds ratio, area under the summary receiver operating characteristic curve, and likelihood ratio.DATA SYNTHESIS: Six studies that included 174 patients qualified for this meta-analysis. The pooled sensitivity, pooled specificity, and area under the summary receiver operating characteristic curve were 0.74 (95% CI, 0.65-0.82), 0.35 (95% CI, 0.03-0.90), and 0.73 (95% CI, 0.69-0.76), respectively. The accuracy of arterial spin-labeling for localizing the epileptic focus was 0.88 (accuracy in arterial spin-labeling/all perfusion changes in arterial spin-labeling) in cases of a positive arterial spin-labeling result. The epileptogenic zone exhibited hyperperfusion or hypoperfusion. LIMITATIONS:Only a few studies were enrolled due to the strict inclusion criteria.CONCLUSIONS: Arterial spin-labeling can be used for assessing, monitoring, and reviewing, postoperatively, patients with epilepsy. Blood perfusion changes in the brain may be closely related to the seizure time and pattern.ABBREVIATIONS: ASL ¼ arterial spin-labeling; QUADAS-2 ¼ Quality Assessment of Diagnostic Accuracy Studies-2; SOZ ¼ seizure onset zone E pilepsy is the most common chronic neurologic disease, characterized by the occurrence of repeat seizures. Several diseases, including brain tumors, hypoxia-related brain diseases, and cerebral cortical dysplasia, can cause epilepsy. Electroencephalography, which identifies the epileptic discharges in the brain, was the earliest method applied for the diagnosis and localization of epileptic disorders. 1,2 The development of imaging technology in recent years has

Arterial Spin Labeling Changes Parallel Asymmetric Perisylvian and Perirolandic Symptoms in 3 Pediatric Cases of Anti-NMDAR Encephalitis

“…The mechanism of increased cerebral blood flow in (predominantly) perisylvian and perirolandic regions is unclear. Analogous to the well-validated ictal and postictal local hyperperfusion by both SPECT 22 and ASL 23 , 24 in focal seizures, the observed changes in our 3 patients may be secondary to focal seizures reflecting local hypermetabolism or compensatory glutamate excitotoxicity rather than direct effect of anti-NMDAR antibodies on the local vessel microenvironment. As anti-NMDAR antibodies are not known to activate complement 25 , 26 or directly produce neuronal cytotoxicity, the follow-up diffusion restriction and ensuing encephalomalacia seen in patient 2 imply indirect cytotoxicity secondary to either repeat and prolonged focal seizures or compensatory glutamate excitotoxicity.…”

Simultaneously Acquired MRI Arterial Spin-Labeling and Interictal FDG-PET Improves Diagnosis of Pediatric Temporal Lobe Epilepsy

“…From recent pooled meta-analyses, sensitivities for interictal FDG-PET and ASL were calculated to be 0.66 and 0.74, respectively, and their specificities, 0.71 and 0.35, respectively. 8,13 Although the sensitivities are similarly modest, FDG-PET has a notable advantage in terms of specificity. The low specificity for epileptogenic foci of ASL is overall indicative of a high false-positive rate.…”

“…Numerous studies have sought to evaluate the effectiveness of ASL techniques in the diagnosis of focal epilepsy during interictal imaging. A recent meta-analysis by Zeng et al 13 analyzed 6 such studies with 174 patients and calculated a pooled sensitivity and specificity of 0.74 and 0.35 for ASL in the localization of epileptic foci. These mediocre diagnostic performance measures imply that ASL is likely best applied as an adjunct diagnostic test to other existing well-validated better performing modalities.…”

Multidelay ASL of the pediatric brain

“…Multimodal imaging approaches are used to lateralize and/or localize the EZ, including anatomic imaging and some combination of ASL, DSC, SPECT, and PET. [90][91][92][93] Concordance between modalities increases the likelihood of seizure-free surgical outcomes. Perfusion imaging findings in epilepsy depend on seizure pattern and timing: in focal epilepsy, the seizure focus shows hypoperfusion in the interictal period and hyperperfusion in the peri-ictal period, with statistical subtraction increasing sensitivity for EZ localization.…”