Dataset Information

Identifying Hypoperfusion in Moyamoya Disease With Arterial Spin Labeling and an [15O]-Water Positron Emission Tomography/Magnetic Resonance Imaging Normative Database.

ABSTRACT: Background and Purpose- Noninvasive imaging of brain perfusion has the potential to elucidate pathophysiological mechanisms underlying Moyamoya disease and enable clinical imaging of cerebral blood flow (CBF) to select revascularization therapies for patients. We used hybrid positron emission tomography (PET)/magnetic resonance imaging (MRI) technology to characterize the distribution of hypoperfusion in Moyamoya disease and its relationship to vessel stenosis severity, through comparisons with a normative perfusion database of healthy controls. Methods- To image CBF, we acquired [15O]-water PET as a reference and simultaneously acquired arterial spin labeling (ASL) MRI scans in 20 Moyamoya patients and 15 age-matched, healthy controls on a PET/MRI scanner. The ASL MRI scans included a standard single-delay ASL scan with postlabel delay of 2.0 s and a multidelay scan with 5 postlabel delays (0.7-3.0s) to estimate and account for arterial transit time in CBF quantification. The percent volume of hypoperfusion in patients (determined as the fifth percentile of CBF values in the healthy control database) was the outcome measure in a logistic regression model that included stenosis grade and location. Results- Logistic regression showed that anterior ( P<0.0001) and middle cerebral artery territory regions ( P=0.003) in Moyamoya patients were susceptible to hypoperfusion, whereas posterior regions were not. Cortical regions supplied by arteries with stenosis on MR angiography showed more hypoperfusion than normal arteries ( P=0.001), but the extent of hypoperfusion was not different between mild-moderate versus severe stenosis. Multidelay ASL did not perform differently from [15O]-water PET in detecting perfusion abnormalities, but standard ASL overestimated the extent of hypoperfusion in patients ( P=0.003). Conclusions- This simultaneous PET/MRI study supports the use of multidelay ASL MRI in clinical evaluation of Moyamoya disease in settings where nuclear medicine imaging is not available and application of a normative perfusion database to automatically identify abnormal CBF in patients.

SUBMITTER: Fan AP

PROVIDER: S-EPMC7161423 | biostudies-literature | 2019 Feb

REPOSITORIES: biostudies-literature

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Identifying Hypoperfusion in Moyamoya Disease With Arterial Spin Labeling and an [<sup>15</sup>O]-Water Positron Emission Tomography/Magnetic Resonance Imaging Normative Database.

Fan Audrey P AP Khalighi Mohammad M MM Guo Jia J Ishii Yosuke Y Rosenberg Jarrett J Wardak Mirwais M Park Jun Hyung JH Shen Bin B Holley Dawn D Gandhi Harsh H Haywood Tom T Singh Prachi P Steinberg Gary K GK Chin Frederick T FT Zaharchuk Greg G

Stroke 20190201 2

Background and Purpose- Noninvasive imaging of brain perfusion has the potential to elucidate pathophysiological mechanisms underlying Moyamoya disease and enable clinical imaging of cerebral blood flow (CBF) to select revascularization therapies for patients. We used hybrid positron emission tomography (PET)/magnetic resonance imaging (MRI) technology to characterize the distribution of hypoperfusion in Moyamoya disease and its relationship to vessel stenosis severity, through comparisons with ...[more]

PMID: 30636572

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Project description:Background and purposeArterial spin-labeling MR imaging with multiple postlabeling delays has a potential to evaluate various hemodynamic parameters. To clarify whether arterial spin-labeling MR imaging can identify CBF and perfusion delay in patients with Moyamoya disease, we compared arterial spin-labeling, DSC, and 15O-gas PET in terms of their ability to identify these parameters.Materials and methodsEighteen patients with Moyamoya disease (5 men, 13 women; ages, 21-55 years) were retrospectively analyzed. CBF values of pulsed continuous arterial spin-labeling using 2 postlabeling delays (short arterial spin-labeling, 1525 ms; delayed arterial spin-labeling, 2525 ms) were compared with CBF values measured by 15O-gas PET. All plots were divided into 2 groups by the cutoff of time-based parameters (the time of the maximum observed concentration, TTP, MTT, delay of MTT to cerebellum, and disease severity [symptomatic or not]). The ratio of 2 arterial spin-labeling CBFs (delayed arterial spin-labeling CBF to short arterial spin-labeling CBF) was compared with time-based parameters: time of the maximum observed concentration, TTP, and MTT.ResultsThe short arterial spin-labeling-CBF values were significantly correlated with the PET-CBF values (r = 0.63; P = .01). However, the short arterial spin-labeling-CBF value dropped in the regions with severe perfusion delay. The delayed arterial spin-labeling CBF overestimated PET-CBF regardless of the degree of perfusion delay. Delayed arterial spin-labeling CBF/short arterial spin-labeling CBF was well correlated with the time of the maximum observed concentration, TTP, and MTT (ρ = 0.71, 0.64, and 0.47, respectively).ConclusionsArterial spin-labeling using 2 postlabeling delays may detect PET-measured true CBF and perfusion delay in patients with Moyamoya disease. Provided its theoretic basis and limitations are considered, noninvasive arterial spin-labeling could be a useful alternative for evaluating the hemodynamics of Moyamoya disease.

Project description:Background:Distinguishing moyamoya disease (MMD) from intracranial atherosclerotic stenosis (IAS) is critical for its treatment and outcome evaluation. This study aimed to use the combined sequences of high-resolution magnetic resonance imaging (HRMRI) and arterial spin labeling MR (ASL-MR) to identify the two entities accurately. Methods:This prospective study enrolled 58 patients with middle cerebral artery (MCA) steno-occlusion identified by digital subtraction angiography (DSA), including 27 cases of MMD and 31 cases of IAS. All patients underwent MRA, HRMRI and ASL-MR prior to DSA. Two radiologists blinded to DSA results analyzed the MR images. The inner and outer diameters of the target arteries, the wall thickness of the stenotic segment, and the perfusion status in the territories of the target arteries [cerebral blood flow (CBF), cerebral blood volume (CBV) and arterial transit time (ATT)] were measured quantitatively. The differences between MMD and IAS regarding the aspects of HRMRI and Pseudo-continuous ASLMR (PCASL-MR) maps were analyzed based on both visual characteristics and data information. Results:Regarding the HRMRI images, MMD tended to have homogeneous and concentric vessel-wall thickening as well as collaterals adjacent to the stenotic vessels; while IAS showed eccentric and heterogeneous vessel-wall thickening. For the CBF maps of PCASL-MR, abnormal hyper-perfused spots embedded inside the hypo-perfused regions were observed in MMD instead of IAS. Quantitative analysis revealed that MMD displayed smaller inner and outer diameters, and smaller maximum wall thickness, higher average value of CBF, CBV and ATT, and higher maximum value of CBF and CBV, when compared to IAS (all P<0.01). The average wall thickness and the maximum value of ATT showed no significant difference between MMD and IAS (P>0.01). Conclusions:HRMRI combined with PCASL-MR may help distinguish MMD and IAS induced cerebral arterial stenosis and cerebral perfusion disorder accurately and non-invasively.

Project description:Cerebrovascular reserve capacity (CVR), an important predictor of ischaemic events and a prognostic factor for patients with moyamoya disease (MMD), can be assessed by measuring cerebral blood flow (CBF) before and after administration of acetazolamide (ACZ). Often, a single CBF measurement is performed between 5 and 20 min after ACZ injection. Assessment of the temporal response of the vasodilation secondary to ACZ administration using several repeated CBF measurements has not been studied extensively. Furthermore, the high standard deviations of the group-averaged CVRs reported in the current literature indicate a patient-specific dispersion of CVR values over a wide range. This study aimed to assess the temporal response of the CBF and derived CVR during ACZ challenge using arterial spin labeling in patients with MMD. Eleven patients with MMD were included before or after revascularisation surgery. CBF maps were acquired using pseudo-continuous arterial spin labeling before and 5, 15, and 25 min after an intravenous ACZ injection. A vascular territory template was spatially normalized to patient-specific space, including the bilateral anterior, middle, and posterior cerebral arteries. CBF increased significantly post-ACZ injection in all vascular territories and at all time points. Group-averaged CBF and CVR values remained constant throughout the ACZ challenge in most patients. The maximum increase in CBF occurred most frequently at 5 min post-ACZ injection. However, peaks at 15 or 25 min were also present in some patients. In 68% of the affected vascular territories, the maximum increase in CBF did not occur at 15 min. In individual cases, the difference in CVR between different time points was between 1 and 30% points (mean difference 8% points). In conclusion, there is a substantial variation in CVR between different time points after the ACZ challenge in patients with MMD. Thus, there is a risk that the use of a single post-ACZ measurement time point overestimates disease progression, which could have wide implications for decision-making regarding revascularisation surgery and the interpretation of the outcome thereof. Further studies with larger sample sizes using multiple CBF measurements post-ACZ injection in patients with MMD are encouraged.

Dataset Information

Identifying Hypoperfusion in Moyamoya Disease With Arterial Spin Labeling and an [15O]-Water Positron Emission Tomography/Magnetic Resonance Imaging Normative Database.

Publications

Identifying Hypoperfusion in Moyamoya Disease With Arterial Spin Labeling and an [<sup>15</sup>O]-Water Positron Emission Tomography/Magnetic Resonance Imaging Normative Database.

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