Technical noteEvaluation of tumor blood flow after feeder embolization in meningiomas by arterial spin-labeling perfusion magnetic resonance imaging
Introduction
Preoperative embolization of meningioma facilitates surgical resection by decreasing intraoperative bleeding and softening tumors. The most commonly accepted indications for preoperative embolization include large and highly vascular convexity meningiomas supplied primarily by the external carotid artery (ECA) [1]. However, there is no standard method for evaluating how much the tumor blood flow is decreased by embolization before surgical resection. In addition, for those tumors supplied mainly by the internal carotid artery (ICA), embolization of the ECA may increase surgical risks [2], [3]. The potential explanation of this is that tumor blood flow and flow distribution patterns are dynamically changed by embolization of one or several of the multiple feeders. This means that preoperative evaluation of flow diversion after embolization is important. Arterial spin-labeling (ASL) perfusion imaging has already been widely used clinically for measuring blood flow in both physiological and pathological states such as brain tumors [4], [5], [6], [7], [8], [9]. In the present study, tumor blood flow in meningioma was measured by ASL perfusion imaging before and after embolization to evaluate changes in blood flow and distribution patterns.
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Patients
This study had the approval of our institutional review board, and all participants gave their written informed consent prior to starting the study. Between April 2011 and March 2012, eight patients with meningioma (two men and six women) underwent embolization at our institution (Table 1). Average age of the patients was 56 years (range: 25–76 years). Tumor locations were convexity (two cases), parasagittal (two cases), falx (one case), sphenoid ridge (one case), tentorial (one case) and
Results
Digital subtraction angiography after embolization demonstrated the disappearance of staining by embolized feeders (data not shown). The pre-embolization T/N ratio was 2.96 ± 0.69 (range: 1.39–7.21) and the post-embolization T/N ratio was 1.98 ± 0.47 (range: 0.43–4.66; Table 1 and Fig. 1). As shown in Fig. 1, the post-embolization T/N ratio decreased in most cases and the difference was statistically significant (P < 0.05 by paired t test). However, the degree and pattern of decrement in tumor blood
Discussion
The devascularization of tumors after embolization is usually evaluated by angiography, contrast-enhanced computed tomography (CT) and MRI. Angiography directly demonstrates the disappearance of tumor staining, while focal defects of enhancement on contrast-enhanced CT and MRI suggest tumor infarction (Fig. 4, lower left). However, these imaging techniques fail to substantially show tumor perfusion status. Dynamic susceptibility contrast (DSC) perfusion imaging is a qualitative MRI perfusion
Disclosure of interest
The authors declare that they have no conflicts of interest concerning this article.
References (14)
- et al.
Grading of adults primitive glial neoplasms using arterial spin-labeled perfusion MR imaging
J Neuroradiol
(2011) - et al.
Preoperative intracranial meningioma embolization
Expert Rev Neurother
(2011) - et al.
Preoperative embolization of intracranial meningiomas
Neurosurgery
(1983) - et al.
Subselective preoperative embolization for meningiomas. A radiological and pathological assessment
J Neurosurg
(1984) - et al.
Arterial spin-labeling in routine clinical practice, part 1: technique and artifacts
AJNR Am J Neuroradiol
(2008) - et al.
Perfusion MRI of brain tumours: a comparative study of pseudo-continuous arterial spin labelling and dynamic susceptibility contrast imaging
Neuroradiology
(2010) - et al.
Perfusion imaging of brain tumors using arterial spin-labeling: correlation with histopathologic vascular density
AJNR Am J Neuroradiol
(2008)
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