Noninvasive Fractional Flow on MRA Predicts Stroke Risk of Intracranial Stenosis

Liebeskind, David S; Kosinski, Andrzej S.; Lynn, Michael; Scalzo, Fabien; Fong, Albert K; Fariborz, Pari; Chimowitz, Marc I.; Feldmann, Edward

doi:10.1111/jon.12101

Cited by 63 publications

(68 citation statements)

References 19 publications

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“…Leng et al [31] demonstrated on CFD models that the translesional pressure gradient has a trend towards being able to predict recurrent ischemic stroke risk in the territory of the treated artery within 1 year. Liebeskind et al [32] reported that the use of the signal intensity ratio index, calculated from the change of signal intensities based on flow-related contrast enhancement on time-of-flight MRA images, was associated with recurrent stroke in the territory of the stenotic artery, irrespective of the anatomical stenosis severity. These noninvasive methods, though attractive, are also in the initial phase of development and are not without their own limitations.…”

Section: Discussionmentioning

confidence: 99%

Fractional Flow Assessment for the Evaluation of Intracranial Atherosclerosis: A Feasibility Study

Miao

Liebeskind

et al. 2016

Intervent Neurol

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Purpose: Current studies on endovascular intervention for intracranial atherosclerosis select patients based on luminal stenosis. Coronary studies demonstrated that fractional flow measurements assess ischemia better than anatomical stenosis and can guide patient selection for intervention. We similarly postulated that fractional flow can be used to assess ischemic stroke risk. Methods: This was a feasibility study to assess the technical use and safety of applying a pressure guidewire to measure fractional flow across intracranial stenoses. Twenty patients with severe intracranial stenosis were recruited. The percentage of luminal stenosis, distal to proximal pressure ratios (fractional flow) and the fractional flow gradients across the stenosis were measured. Procedural success rate and safety outcomes were documented. Results: All 20 patients had successful crossing of stenosis by the pressure guidewire. Ten patients underwent angioplasty, and 5 had stenting performed. There was one perforator stroke, but not related to the use of the pressure wire. For the 13 patients with complete pre- and postintervention data, the mean preintervention stenosis, fractional flow and translesional pressure gradient were 76.2%, 0.66 and 29.9 mm Hg, whilst the corresponding postintervention measurements were 24.7%, 0.88 and 10.9 mm Hg, respectively. Fractional flow (r = -0.530, p = 0.001) and the translesional pressure gradient (r = 0.501, p = 0.002) only had a modest correlation with the luminal stenosis. Conclusion: Fractional flow measurement by floating a pressure guidewire across the intracranial stenosis was technically feasible and safe in this study. Further studies are needed to validate its use for ischemic stroke risk assessment.

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Section: Discussionmentioning

confidence: 99%

Fractional Flow Assessment for the Evaluation of Intracranial Atherosclerosis: A Feasibility Study

Miao

Liebeskind

et al. 2016

Intervent Neurol

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“…Comparison of the signal intensity on TOF MRA proximal and distal to a symptomatic intracranial stenosis may be a reasonable measure of fractional flow reserve associated with the stenosis. A post-hoc analysis of patients in the WASID and SONIA trials suggests that patients with distal to proximal signal ratios of less than 0·9 on TOF MRA are at a higher risk of stroke than are those with ratios of 0·9 or greater 124 .…”

Section: Future Directionsmentioning

confidence: 99%

Stroke Caused by Atherosclerosis of the Major Intracranial Arteries

Banerjee¹,

Chimowitz²

2017

Journal of Vascular Surgery

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Our goal in this review is to discuss the pathophysiology, diagnosis and treatment of stroke caused by atherosclerosis of the major intracranial arteries. References for the review were identified by searching PubMed for related studies published from 1955 to June 2016 using search terms "intracranial stenosis" and "intracranial atherosclerosis". Reference sections of published randomized clinical trials and previously published reviews were searched for additional references. Intracranial atherosclerotic disease (ICAD) is a highly prevalent cause of stroke that is associated with a high risk of recurrent stroke. It is more prevalent among blacks, Hispanics and Asians compared with whites. Diabetes, hypertension, metabolic syndrome, smoking, hyperlipidemia and a sedentary lifestyle are the major modifiable risk factors associated with ICAD. Randomized clinical trials comparing aggressive management (dual antiplatelet treatment for 90 days followed by aspirin monotherapy and intensive management of vascular risk factors) with intracranial stenting plus aggressive medical management have shown medical management alone to be safer and more effective for preventing stroke. As such, aggressive medical management has become the standard of care for symptomatic patients with ICAD. Nevertheless, there are subgroups of patients who are still at high risk of stroke despite being treated with aggressive medical management. Future research should aim to establish clinical, serologic, and imaging biomarkers to identify high-risk patients, and clinical trials evaluating novel therapies should be focused on these patients.

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“…The index SIR of ICAS on TOF-MRA has been demonstrated to be of high inter-observer reproducibility, as reported in our previous study [12]. In theory, SIR across an ICAS may reflect hemodynamic features of the stenosis, and has been proven to be associated with recurrent stroke in the relevant territory in patients with symptomatic ICAS [11,14,17]. However, the capacity of SIR to represent the hemodynamic changes of stenosis needed to be verified, so that it could be further utilized in assessment and risk stratification of affected patients.…”

Section: Discussionmentioning

confidence: 75%

“…1) [11,12,14]. In brief, SIs proximal or distal to a target lesion were measured on MRA by outlining a 3-mm-length region of interest (ROI) covering the arterial lumen.…”

Section: Methodsmentioning

confidence: 99%

Diminished Signal Intensities Distal to Intracranial Arterial Stenosis on Time-of-Flight MR Angiography Might Indicate Delayed Cerebral Perfusion

et al. 2016

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Background: Intracranial arterial stenosis (ICAS) is a predominant cause of ischemic stroke in Asia. Changes in the signal intensities (SIs) across ICAS lesions on time-of-flight magnetic resonance angiography (TOF-MRA) have been indicated to partially reflect the hemodynamic significance of the lesions, which we aimed to verify by correlating it with cerebral perfusion features provided by CT perfusion (CTP) imaging. Methods: Ischemic stroke or transient ischemic attack patients with unilateral symptomatic stenosis (≥50%) of intracranial internal carotid artery or middle cerebral artery (MCA) were included in this study. Change of SIs across an ICAS lesion on TOF-MRA was calculated by the distal and proximal SI ratio (SIR). Cerebral blood volume (CBV), cerebral blood flow (CBF), and mean transit time (MTT) within the MCA territory of ipsilateral and contralateral hemispheres were evaluated on the CTP images at the basal ganglia level. Relative CBV, CBF and MTT were defined as ratios of the values obtained from ipsilateral and contralateral hemispheres. The relationships between SIR and CTP parameters were analyzed. Results: Fifty subjects (74% male, mean age 62) were recruited. Overall, the mean SIR was 0.77 ± 0.17. SIR of ICAS was significantly, linearly and negatively correlated with ipsilateral CBV (r = -0.335, p = 0.017), ipsilateral MTT (r = -0.301, p = 0.034), and ipsilateral/contralateral MTT ratio (r = -0.443, p = 0.001). Conclusions: Diminished SIs distal to ICAS on TOF-MRA might be associated with delayed ipsilateral cerebral perfusion. Changes of the SIs across ICAS lesions on TOF-MRA may be a simple marker to reflect cerebral perfusion changes in patients with symptomatic ICAS.

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Noninvasive Fractional Flow on MRA Predicts Stroke Risk of Intracranial Stenosis

Cited by 63 publications

References 19 publications

Fractional Flow Assessment for the Evaluation of Intracranial Atherosclerosis: A Feasibility Study

Fractional Flow Assessment for the Evaluation of Intracranial Atherosclerosis: A Feasibility Study

Stroke Caused by Atherosclerosis of the Major Intracranial Arteries

Diminished Signal Intensities Distal to Intracranial Arterial Stenosis on Time-of-Flight MR Angiography Might Indicate Delayed Cerebral Perfusion

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