scholarly journals Reduced magnetic resonance angiography signal intensity in the middle cerebral artery ipsilateral to severe carotid stenosis may be a practical index of high oxygen extraction fraction

2021 ◽  
Author(s):  
Takahisa Mori ◽  
Kazuhiro Yoshioka ◽  
Yuhei Tanno ◽  
Shigen Kasakura ◽  
Yuichi Miyazaki
Keyword(s):  
Carotid Artery ◽  
Middle Cerebral Artery ◽  
Carotid Stenosis ◽  
Signal Intensity ◽  
Oxygen Extraction Fraction ◽  
Slow Flow ◽  
Luminal Diameter ◽  
Relative Signal Intensity ◽  
Extraction Fraction ◽  
Minimal Luminal Diameter

Abstract Objectives Angiographic “slow flow” in the middle cerebral artery (MCA), caused by carotid stenosis, may be associated with high oxygen extraction fraction (OEF). If the MCA slow flow is associated with a reduced relative signal intensity (rSI) of the MCA on MR angiography, the reduced rSI may be associated with a high OEF. We investigated whether the MCA slow flow ipsilateral to carotid stenosis was associated with a high OEF and aimed to create a practical index to estimate the high OEF. Methods We included patients who underwent digital subtraction angiography (DSA) and MRA between 2015 and 2019 to evaluate carotid stenosis. MCA slow flow by image count using DSA, MCA rSI, minimal luminal diameter (MLD) of the carotid artery, carotid artery stenosis rate (CASr), and whole-brain OEF (wb-OEF) was evaluated. When MCA slow flow was associated with a high wb-OEF, the determinants of MCA slow flow were identified, and their association with high wb-OEF was evaluated. Results One hundred and twenty-seven patients met our inclusion criteria. Angiographic MCA slow flow was associated with high wb-OEF. We identified MCA rSI and MLD as determinants of angiographic MCA slow flow. The upper limits of MCA rSI and MLD for angiographic MCA slow flow were 0.89 and 1.06 mm, respectively. The wb-OEF was higher in patients with an MCA rSI ≤ 0.89 and ipsilateral MLD ≤ 1.06 mm than patients without this combination. Conclusions The combination of reduced MCA rSI and ipsilateral narrow MLD is a straightforward index of high wb-OEF. Key Points • The whole-brain OEF in patients with angiographic slow flow in the MCA ipsilateral to high-grade carotid stenosis was higher than in patients without it. • Independent determinants of MCA slow flow were MCA relative signal intensity (rSI) on MRA or minimal luminal diameter (MLD) of the carotid stenosis. • The wb-OEF was higher in patients with an MCA rSI ≤ 0.89 and ipsilateral MLD ≤ 1.06 mm than patients without this combination.

Abstract P509: Signal Intensity in the Middle Cerebral Artery as a Practical and Feasible Index of Hemodynamic Insufficiency Due to Carotid Artery Stenosis

Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Takahisa Mori ◽  
Kazuhiro Yoshioka ◽  
Yuichi Miyazaki
Keyword(s):  
Carotid Artery ◽  
Middle Cerebral Artery ◽  
Cerebral Artery ◽  
Roc Curve ◽  
Signal Intensity ◽  
Single Photon ◽  
Photon Emission ◽  
Oxygen Extraction Fraction ◽  
Arterial Oxygen ◽  
Upper Limit

Introduction: Intracranial hemorrhage occasionally occurs after carotid revascularization in presents with hemodynamic insufficiency. Positron emission tomography is unavailable in most facilities, and a feasible index is required to identify high-risk patients. Reduced signal intensity (SI) of the middle cerebral artery (MCA) on magnetic resonance angiography (MRA) is associated with postoperative hyperperfusion. Hypothesis: Reduced signal intensity (SI) of the MCA on MRA is associated with decreased regional cerebral blood flow (rCBF) on single-photon emission CT (SPECT) and increased blood-sampling whole-brain oxygen extraction fraction (wb-OEF). Methods: We included patients who: 1) were admitted from 2015 to 2019 for carotid artery stenting (CAS), 2) MRA, and SPECT before CAS, and 3) examined the wb-OEF immediately before CAS. We measured bilateral MCA SI on MRA and defined the MCA relative SI as (SI in the affected MCA)/ (SI in the contralateral MCA). We defined the rCBF% as rCBF in the affected MCA territory against the ipsilateral cerebellum. Before CAS, we sampled blood, measured the arterial oxygen and the venous oxygen content in the dominant-sided jugular vein, and calculated the wb-OEF. We evaluated the correlation between the MCA relative SI, the MCA slow flow, the rCBF%, and the wb-OEF. We estimated the upper limits of the MCA relative SI for the rCBF% < 80% or wb-OEF ≥ 0.40 using the area under the curve (AUC) values derived from the receiver operating characteristic (ROC) curves. Results: During the study period, 150 patients met our inclusion criteria. The MCA relative SI was positively correlated with rCBF% and negatively with the wb-OEF. The ROC curve for the rCBF% < 80% showed that the upper limit of the relative SI was 0.77 (the sensitivity of 53.9%, the specificity of 83.9%, AUC of 0.723). The ROC curve for the wb-OEF ≥ 0.40 showed that the upper limit of the relative SI was 0.95 (the sensitivity of 67.7%, the specificity of 55.2%, AUC of 0.625). Conclusion: Reduced MCA SI on MRA ≤ 0.77 is a practical and feasible index of hemodynamic insufficiency, indicating the decreased rCBF and increased wb-OEF.

scholarly journals Analysis of postprocedural microembolic infarctions and global oxygen extraction fraction during balloon-protected carotid artery stenting: Preliminary study

2021 ◽  
Vol 12 ◽  
pp. 87
Author(s):  
Hidemichi Ito ◽  
Masashi Uchida ◽  
Hiroshi Takasuna ◽  
Ichiro Takumi ◽  
Tanaka Yuichiro
Keyword(s):  
Cerebral Ischemia ◽  
Carotid Artery ◽  
Carotid Stenosis ◽  
Carotid Artery Stenting ◽  
Cerebral Hypoperfusion ◽  
Oxygen Extraction Fraction ◽  
Oxygen Extraction ◽  
Black Blood ◽  
Extraction Fraction ◽  
Carotid Flow

Background: Atherosclerotic carotid stenosis with impaired cerebral perfusion is a risk factor for cerebral ischemia. In major carotid stenoocclusive diseases, increased oxygen extraction fraction (OEF) is associated with ischemic stroke. Balloon-protected carotid artery stenting (CAS) is valuable for high-grade carotid stenosis. However, while balloon-protected CAS can effectively reduce the occurrence of ischemic complications by blocking carotid flow, cerebral hypoperfusion may result in simultaneous cerebral ischemia. We sought to evaluate whether increased OEF during balloon-protected CAS can predict postprocedural microembolic infarction (MI). Methods: Eighty-four patients who underwent balloon-protected CAS were enrolled. Initial, intraprocedural, and postprocedural OEFs were calculated from the cerebral arteriovenous oxygen differences obtained from blood sampled just before the temporary occlusion and reperfusion of the internal carotid artery during and after the procedure. MIs were evaluated by diffusion-weighted imaging (DWI). Patients were classified into two groups based on the presence or absence of new MIs, and the relationship between the OEF and postprocedural MIs was analyzed. Results: New DWI-positive lesions were found in 37 cases (44.0%). Age, signal intensity ratio (SIR) of carotid plaque on T1-weighted black blood magnetic resonance imaging, and intraprocedural OEF were significantly higher in the DWI-positive group. The high SIR and intraprocedural OEF were significantly associated with the development of postprocedural MIs in multivariate analysis. MIs were correlated with the increase in OEF. Conclusion: Increased intraprocedural OEF, obtained by blood sampling during balloon-protected CAS, could predict the incidence of postprocedural MIs. Patients with carotid stenosis could be hemodynamically compromised by carotid flow blockage during balloon-protected CAS.

Abstract W P115: Utilization of Blood Sampling Global Oxygen Extraction Fraction and SPECT to Anticipate Cerebral Hyperperfusion Syndrome Following Elective Carotid Artery Stenting

Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
Takahisa Mori ◽  
Tomonori Iwata ◽  
Yuhei Tanno ◽  
Shigen Kasakura ◽  
Yoshinori Aoyagi ◽  
...  
Keyword(s):  
Carotid Artery ◽  
Carotid Artery Stenting ◽  
Blood Sampling ◽  
Oxygen Extraction Fraction ◽  
Oxygen Extraction ◽  
Cerebral Hyperperfusion Syndrome ◽  
Hyperperfusion Syndrome ◽  
Cerebral Hyperperfusion ◽  
Arterial Blood ◽  
Extraction Fraction

Background: It is required to anticipate cerebral hyperperfusion syndrome (CHS) following carotid artery stenting (CAS). Purpose: The purpose of our retrospective study was to investigate whether or not blood sampling oxygen extraction fraction (OEF) and post-CAS CBF increase in SPECT had relation to CHS following CAS. Methods: Included in our analysis were patients (1) who underwent elective CAS in our institution between October 2010 and May 2014, and (2) who underwent blood sampling for OEF calculation before and immediately after CAS, and (3) who underwent SPECT before and just after CAS. OEF was calculated from cerebral arteriovenous oxygen difference. Arterial blood was sampled from the common carotid artery and venous blood from the dominant-sided superior jugular bulb. CHS was defined as pulsatile headaches, restlessness, convulsion, and/or new neurological symptoms not due to cerebral ischemia within seven days following CAS. CBF was measured before and just after CAS. CBF increase in the CAS side was defined as follows; (post-CAS CBF ratio - pre-CAS CBF ratio) of more than 10%, where CBF ratio was defined as CAS-sided fronto-parietal CBF divided by ipsilateral cerebellar CBF (%). Evaluated were baseline features in patients, pre-CAS OEF, post-CAS OEF, CBF ratio, CBF increase and CHS. Results: During the study period, 134 patients matched our criteria for analysis. Pre-CAS OEF was 0.41+-0.06, post-CAS OEF was 0.42+-0.08, pre-CAS CBF ratio: 88.7+-15.4%, CBF increase: 1.86+-12.3%. Nine patients presented CHS. Among them, pre-CAS OEF, CBF ratio and CBF increase were significant. ROC curves showed that pre-CAS OEF of 0.46 (p<0.001, OR: 9.3), CBF ratio of 92%(p<0.05, OR: 6.5), CBF increase of 8.8% (p<0.005, OR: 6.6) were cut-off values. Among 10 patients with pre-CAS OEF of more than 0.46 and CBF increase of more than 8.8%, 4 patients presented CHS (p<0.0001, OR;15.9). Conclusion: Elevation of pre-CAS OEF and increase of post-CAS CBF were strongly related to CHS.

scholarly journals Predictors of the pulsatility index in the middle cerebral artery of acute stroke patients

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Olivier Bill ◽  
Dimitris Lambrou ◽  
Guillermo Toledo Sotomayor ◽  
Ivo Meyer ◽  
Patrik Michel ◽  
...  
Keyword(s):  
Carotid Artery ◽  
Middle Cerebral Artery ◽  
Carotid Stenosis ◽  
Flow Pattern ◽  
Cerebral Artery ◽  
Carotid Artery Stenosis ◽  
Pulsatility Index ◽  
Artery Stenosis ◽  
Doppler Velocity ◽  
High Grade

Abstract Cervical and transcranial Doppler (TCD) are widely used as non-invasive methods in the evaluation of acute ischemic stroke (AIS) patients. High-grade carotid artery stenosis induces haemodynamic changes such as collateral flow and a so-called post-stenotic flow pattern of the middle cerebral artery (MCA), which appears flattened, with a reduction of the velocity difference between systole and diastole. We studied the influence of carotid artery stenosis and other variables on the flow pattern in the MCA using the pulsatility index (PI), a quantitative TCD parameter reflecting the flow spectrum in a large of cohort AIS patients. We performed ultrasound examinations of 1825 AIS patients at the CHUV from October 2004 to December 2014. We extracted patient characteristics from the ASTRAL registry. Carotid stenosis severity was classified as < 50%, 50–70%, 70–90% and > 90%, or occlusion, according to Doppler velocity criteria. We first determined variables associated with stenosis grade. Then we performed a multivariate analysis after adjusting for baseline differences, using MCA PI as dependent variable. Carotid stenosis > 70% (− 0.07) and carotid stenosis > 90%, or occlusion (− 0.14) and left side (− 0.02) are associated with lower MCA PI values. Age (+0.006 PI units per decade), diabetes (+0.07), acute ischemic changes on initial CT (+0.03) and severe plaque morphology (+0.18) are associated with higher MCA PI values. We found a number of clinical and radiological conditions that significantly influence the PI of the MCA, including high-grade ipsilateral carotid stenosis in AIS patients. We provide for the first time a quantitative evaluation of the effect of these influencing factors from a large cohort of AIS patients.

Global Oxygen Extraction Fraction by Blood Sampling to Anticipate Cerebral Hyperperfusion Phenomenon After Carotid Artery Stenting

Neurosurgery ◽  
2014 ◽  
Vol 75 (5) ◽  
pp. 546-551 ◽  
Author(s):  
Tomonori Iwata ◽  
Takahisa Mori ◽  
Yuichi Miyazaki ◽  
Yuhei Tanno ◽  
Shigen Kasakura ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Carotid Artery ◽  
Carotid Artery Stenting ◽  
Blood Sampling ◽  
Oxygen Extraction Fraction ◽  
Cerebral Hyperperfusion Syndrome ◽  
Hyperperfusion Syndrome ◽  
Cerebral Hyperperfusion ◽  
Extraction Fraction

Abstract BACKGROUND: Cerebral hyperperfusion syndrome sometimes occurs after carotid revascularization in patients with severe hemodynamic failure. To prevent cerebral hyperperfusion syndrome, cerebral hyperperfusion phenomenon (CHP) must be detected early. Single-photon emission computed tomography (SPECT) is useful for detecting CHP, but it is impractical on a daily basis. A tool with high availability to find CHP is desired. OBJECTIVE: To investigate whether global oxygen extraction fraction (OEF) by a blood sampling method is useful for indicating CHP after carotid artery stenting (CAS). METHODS: When patients underwent elective CAS from September 2010 to August 2012, we performed blood sampling for OEF calculation and SPECT before and immediately after elective CAS. Data were collected prospectively. OEF was calculated from the cerebral arteriovenous oxygen difference. Cerebral blood flow was measured in the affected middle cerebral artery (MCA) territory and in the ipsilateral cerebellum by SPECT. The ratio of MCA to cerebellar activity was defined as cerebral blood flow in the affected MCA territory divided by cerebral blood flow in the ipsilateral cerebellar hemisphere. Probable CHP was defined as ≥10% increase in the ratio of MCA to cerebellar activity after CAS. The relationship between peri-CAS OEF and probable CHP was evaluated. RESULTS: Of the 96 patients enrolled, 92 patients were analyzed. Probable CHP occurred in 17 patients. Post-CAS OEF was related to probable CHP (P &lt; .01), but pre-CAS OEF was not. The receiver-operating characteristic curve showed that the cutoff value was 45% for probable CHP (P &lt; .001). CONCLUSION: An increase in blood sampling OEF immediately after CAS was related to probable CHP; then the oxygen demand should be reduced.

scholarly journals Identification of Collaterally Perfused Areas following Focal Cerebral Ischemia in the Rat by Comparison of Gradient Echo and Diffusion-Weighted MRI

1995 ◽  
Vol 15 (4) ◽  
pp. 578-586 ◽  
Author(s):  
S. A. Roussel ◽  
N. van Bruggen ◽  
M. D. King ◽  
D. G. Gadian
Keyword(s):  
Signal Intensity ◽  
Magnetic Resonance Images ◽  
Core Area ◽  
Oxygen Extraction Fraction ◽  
Oxygen Extraction ◽  
Great Promise ◽  
Gradient Echo ◽  
The Core ◽  
Extraction Fraction ◽  
Diffusion Weighted

Diffusion-weighted (DW) and gradient echo (GE) magnetic resonance images were acquired before and after occlusion of the middle cerebral artery (MCA) in the rat. Upon occlusion, an increase in DW imaging signal intensity was observed in a core area within the MCA territory, most likely reflecting cytotoxic edema. The signal from GE images, which is sensitive to changes in the absolute amount of deoxyhemoglobin, decreased following ischemia within a region that extended beyond the core area observed with DW imaging. This hypointensity is attributed to increases in blood volume and/or oxygen extraction fraction, which result from a decrease in perfusion pressure in the collaterally perfused area. The evolution of the GE imaging signal intensity from different regions was studied for 3.5 h following the occlusion. In the core area, the GE imaging signal returned towards baseline values after ∼1–2 h, while it remained stable in the surrounding area. This feature may reflect a decrease in hematocrit due to microcirculatory defect and/or a decrease in the oxygen extraction fraction due to ongoing infarction of the tissue and may indicate that tissue recovery is severely compromised. The combined use of DW and GE imaging offers great promise for the noninvasive identification of specific pathological events with high spatial resolution.

scholarly journals Hemodynamics and oxygen extraction in chronic large artery steno-occlusive disease: Clinical applications for predicting stroke risk

2017 ◽  
Vol 38 (9) ◽  
pp. 1584-1597 ◽  
Author(s):  
Colin P Derdeyn
Keyword(s):  
Blood Flow ◽  
Ischemic Stroke ◽  
Carotid Artery ◽  
Stroke Risk ◽  
Arterial Stenosis ◽  
Oxygen Extraction Fraction ◽  
Oxygen Extraction ◽  
Large Artery ◽  
Extraction Fraction ◽  
Hemodynamic Assessment

Depending on the adequacy of collateral sources of blood flow, arterial stenosis or occlusion may lead to reduced perfusion pressure and ultimately reduced blood flow in the distal territory supplied by that vessel. There are two well-defined compensatory mechanisms to reduced pressure or flow – autoregulatory vasodilation and increased oxygen extraction fraction. Other changes, such as metabolic downregulation, are likely. The positive identification of autoregulatory vasodilation and increased oxygen extraction fraction in humans is an established risk factor for future ischemic stroke in some disease states such as atherosclerotic carotid stenosis and occlusion. The mechanisms by which ischemic stroke may occur are not clear, and may include an increased vulnerability to embolic events. The use of hemodynamic assessment to identify patients with occlusive vasculopathy at an increased risk for stroke is very appealing for several different patient populations, such as those with symptomatic intracranial atherosclerotic disease, moyamoya phenomenon, complete internal carotid artery occlusion, and asymptomatic cervical carotid artery stenosis. While there is very good data for stroke risk prediction in some of these groups, no intervention based on these tools has been proven effective yet. In this manuscript, we will review these topics above and identify areas for future research.

Measurement of oxygen extraction fraction by blood sampling to estimate severe cerebral hemodynamic failure and anticipate cerebral hyperperfusion syndrome following carotid artery stenting

2018 ◽  
Vol 10 (11) ◽  
pp. 1063-1066 ◽  
Author(s):  
Tomonori Iwata ◽  
Takahisa Mori ◽  
Yuhei Tanno ◽  
Shigen Kasakura ◽  
Kazuhiro Yoshioka
Keyword(s):  
Carotid Artery ◽  
Carotid Artery Stenting ◽  
Blood Sampling ◽  
Oxygen Extraction Fraction ◽  
Oxygen Extraction ◽  
Cerebral Hyperperfusion Syndrome ◽  
Hyperperfusion Syndrome ◽  
Cerebral Hyperperfusion ◽  
Extraction Fraction ◽  
Hemodynamic Failure

BackgroundCerebral hyperperfusion syndrome (CHS) is likely to occur after carotid revascularization in patients with stage 2 hemodynamic failure (st2HF), in whom the oxygen extraction fraction (OEF) increases.ObjectiveThe purpose of our study was to investigate whether measurement of the global cerebral OEF (gcOEF) by blood sampling can be used to estimate st2HF and anticipate CHS following carotid artery stenting (CAS).MethodsThe OEF was calculated by blood sampling just before and after elective CAS. Data were collected prospectively. Patients who underwent elective CAS and gcOEF calculation were included in the study. Patients’ baseline features, pre-CAS gcOEF, post-CAS gcOEF, and incidence of CHS (defined as headache, seizure, focal neurologic deficits, and/or restlessness) were evaluated.Results141 patients met the inclusion criteria and 134 patients were analyzed. Median pre-CAS gcOEF and post-CAS gcOEF were 0.41 and 0.42, respectively. Nine patients developed CHS. Median pre-CAS gcOEF was higher in patients with than in those without CHS (Mann–Whitney U test, P<0.05), but median post-CAS gcOEF was not significantly higher in patients with CHS (P=0.058). Scattergrams of patients with and without CHS showed that the cut-off values of the pre-CAS gcOEF and post-CAS gcOEF for anticipation of CHS were 0.46 (P<0.01) and 0.49 (P<0.001), respectively.ConclusionElevation of the pre-CAS or post-CAS gcOEF by blood sampling allowed for anticipation of CHS following CAS. Elevation of the pre-CAS gcOEF might be associated with st2HF.

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