Abstract
PurposePatients with Moyamoya Angiopathy (MMA) require hemodynamic evaluation to assess the risk of stroke. Assessment of cerebral blood flow with [15O]water PET and acetazolamide challenge is the diagnostic standard for the evaluation of the cerebral perfusion reserve (CPR). Estimation of the cerebrovascular reactivity (CVR) by use of breath-hold-triggered fMRI (bh-fMRI) as an index of CPR has been proposed as a reliable and more readily available approach. Recent findings suggest the use of resting-state fMRI (rs-fMRI) which requires minimum patient compliance. The aim of this study was to compare rs-fMRI to bh-fMRI and [15O]water PET in patients with MMA.MethodsPatients with MMA underwent rs-fMRI and bh-fMRI in the same MRI session. Maps of the CVR gained by both modalities were compared retrospectively by calculating the correlation between the mean CVR of 12 volumes of interest. Additionally, the rs-maps of a subgroup of patients were compared to CPR-maps gained by [15O]water PET.ResultsThe comparison of the rs-maps and the bh-maps of 24 patients revealed a good correlation (Pearson’s r = 0.71 ± 0.13; preoperative patients: Pearson’s r = 0.71 ± 0.17; postoperative patients: Pearson’s r = 0.71 ± 0.11). The comparison of 7 rs-fMRI data sets to the corresponding [15O]water PET data sets also revealed a high level of agreement (Pearson’s r = 0.80 ± 0.19).ConclusionThe present analysis indicates that rs-fMRI might be a promising non-invasive method with almost no patient cooperation needed to evaluate the CVR. Further prospective studies are required.
Highlights
Moyamoya Angiopathy (MMA) is a progressive stenoocclusive arteriopathy of terminal parts of the internal carotid arteries and the circle of Willis [1] resulting in reactive collateralization from new vessels
Functional bloodoxygen-level-dependent (BOLD) fMRI with hypercapnic stimulation provides a more widely available but comparable alternative by measuring the cerebrovascular reactivity (CVR), which is defined as the change in cerebral perfusion in response to a vasodilatory stimulus as an index for the cerebral perfusion reserve (CPR) [10]. CO2 is a potent vasodilatory stimulus that leads to increased perfusion in brain tissue with unimpacted CVR [12]
25 resting-state fMRI (rs-fMRI) data sets of 24 patients with MMA were analyzed and compared to the corresponding breath-hold-triggered fMRI (bh-fMRI) data sets and seven of the rs-fMRI data sets were compared to the corresponding [15O]water PET data sets
Summary
Moyamoya Angiopathy (MMA) is a progressive stenoocclusive arteriopathy of terminal parts of the internal carotid arteries and the circle of Willis [1] resulting in reactive collateralization from new vessels. If a reduced cerebral perfusion reserve capacity is seen on functional imaging, patients have an increased risk of stroke. For the indication of neurosurgical revascularization cerebral perfusion reserve (CPR) must be measured by functional perfusion imaging [6, 7]. Functional bloodoxygen-level-dependent (BOLD) fMRI with hypercapnic stimulation provides a more widely available but comparable alternative by measuring the cerebrovascular reactivity (CVR), which is defined as the change in cerebral perfusion in response to a vasodilatory stimulus as an index for the CPR [10]. Hypercapnia can be achieved by the inhalation of CO2-enriched gas [12, 14,15,16,17,18,19] or by performing short breath-hold periods [10, 12, 20,21,22,23]. Breath-holding (bh) is an implementable method to achieve hypercapnia and does not require any additional equipment [11, 26, 27], but relies on the patients’ cooperation [11, 12]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
