1
|
Holmgren M, Henze A, Wåhlin A, Eklund A, Fox AJ, Johansson E. Phase-contrast magnetic resonance imaging of intracranial and extracranial blood flow in carotid near-occlusion. Neuroradiology 2024; 66:589-599. [PMID: 38400954 PMCID: PMC10937755 DOI: 10.1007/s00234-024-03309-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 02/08/2024] [Indexed: 02/26/2024]
Abstract
PURPOSE Compare extracranial internal carotid artery flow rates and intracranial collateral use between conventional ≥ 50% carotid stenosis and carotid near-occlusion, and between symptomatic and asymptomatic carotid near-occlusion. METHODS We included patients with ≥ 50% carotid stenosis. Degree of stenosis was diagnosed on CTA. Mean blood flow rates were assessed with four-dimensional phase-contrast MRI. RESULTS We included 110 patients of which 83% were symptomatic, and 38% had near-occlusion. Near-occlusions had lower mean internal carotid artery flow (70 ml/min) than conventional ≥ 50% stenoses (203 ml/min, P < .001). Definite use of ≥ 1 collateral was found in 83% (35/42) of near-occlusions and 10% (7/68) of conventional stenoses (P < .001). However, there were no differences in total cerebral blood flow (514 ml/min vs. 519 ml/min, P = .78) or ipsilateral hemispheric blood flow (234 vs. 227 ml/min, P = .52), between near-occlusions and conventional ≥ 50% stenoses, based on phase-contrast MRI flow rates. There were no differences in total cerebral or hemispheric blood flow, or collateral use, between symptomatic and asymptomatic near-occlusions. CONCLUSION Near-occlusions have lower internal carotid artery flow rates and more collateral use, but similar total cerebral blood flow and hemispheric blood flow, compared to conventional ≥ 50% carotid stenosis.
Collapse
Affiliation(s)
- Madelene Holmgren
- Department of Clinical Sciences, Neurosciences, Umeå University, Umeå, Sweden
- Department of Radiation Sciences, Biomedical Engineering, Umeå University, Umeå, Sweden
| | - Alexander Henze
- Department of Radiation Sciences, Biomedical Engineering, Umeå University, Umeå, Sweden
| | - Anders Wåhlin
- Department of Radiation Sciences, Biomedical Engineering, Umeå University, Umeå, Sweden
- Umeå Center for Functional Brain Imaging, Umeå University, Umeå, Sweden
- Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden
| | - Anders Eklund
- Department of Radiation Sciences, Biomedical Engineering, Umeå University, Umeå, Sweden
- Umeå Center for Functional Brain Imaging, Umeå University, Umeå, Sweden
| | - Allan J Fox
- Sunnybrook Health Science Center, University of Toronto, Toronto, Canada
| | - Elias Johansson
- Department of Clinical Sciences, Neurosciences, Umeå University, Umeå, Sweden.
- Wallenberg Center for Molecular Medicine, Umeå University, Umeå, Sweden.
- Neuroscience and Physiology, Gothenburg University, Göteborg, Sweden.
| |
Collapse
|
2
|
Holmgren M, Henze A, Wåhlin A, Eklund A, Fox AJ, Johansson E. Diagnostic separation of conventional ⩾50% carotid stenosis and near-occlusion with phase-contrast MRI. Eur Stroke J 2024; 9:135-143. [PMID: 38032058 PMCID: PMC10916822 DOI: 10.1177/23969873231215634] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 11/03/2023] [Indexed: 12/01/2023] Open
Abstract
INTRODUCTION The aim of this study was to assess sensitivity, specificity and interrater reliability of phase-contrast MRI (PC-MRI) for diagnosing carotid near-occlusion. PATIENTS AND METHODS Prospective cross-sectional study conducted between 2018 and 2021. We included participants with suspected 50%-100% carotid stenosis on at least one side, all were examined with CT angiography (CTA) and PC-MRI and both ICAs were analyzed. Degree of stenosis on CTA was the reference test. PC-MRI-based blood flow rates in extracranial ICA and intracranial cerebral arteries were assessed. ICA-cerebral blood flow (CBF) ratio was defined as ICA divided by sum of both ICAs and Basilar artery. RESULTS We included 136 participants. The ICAs were 102 < 50% stenosis, 88 conventional ⩾50% stenosis (31 with ⩾70%), 49 near-occlusion, 12 occlusions, 20 unclear cause of small distal ICA on CTA and one excluded. For separation of near-occlusion and conventional stenoses, ICA flow rate and ICA-CBF ratio had the highest area under the curve (AUC; 0.98-0.99) for near-occlusion. ICA-CBF ratio ⩽0.225 was 90% (45/49) sensitive and 99% (188/190) specific for near-occlusion. Inter-rater reliability for this threshold was excellent (kappa 0.98). Specificity was 94% (29/31) for cases with ⩾70% stenosis. PC-MRI had modest performance for separating <50% and conventional ⩾50% stenosis (highest AUC 0.74), and eight (16%) of near-occlusions were not distinguishable from occlusion (no visible flow). CONCLUSION ICA-CBF ratio ⩽0.225 on PC-MRI is an accurate and reliable method to separate conventional ⩾50% stenosis and near-occlusion that is feasible for routine use. PC-MRI should be considered further as a potential standard method for near-occlusion detection, to be used side-by-side with established modalities as PC-MRI cannot separate other degrees of stenosis.
Collapse
Affiliation(s)
- Madelene Holmgren
- Department of Clinical Sciences, Neurosciences, Umeå University, Umeå, Sweden
- Department of Radiation Sciences, Biomedical Engineering, Umeå University, Umeå, Sweden
| | - Alexander Henze
- Department of Radiation Sciences, Biomedical Engineering, Umeå University, Umeå, Sweden
| | - Anders Wåhlin
- Department of Radiation Sciences, Biomedical Engineering, Umeå University, Umeå, Sweden
- Umeå Center for Functional Brain Imaging, Umeå University, Umeå, Sweden
- Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden
| | - Anders Eklund
- Department of Radiation Sciences, Biomedical Engineering, Umeå University, Umeå, Sweden
- Umeå Center for Functional Brain Imaging, Umeå University, Umeå, Sweden
| | - Allan J Fox
- Sunnybrook Health Science Center, University of Toronto, Toronto, ON, Canada
| | - Elias Johansson
- Department of Clinical Sciences, Neurosciences, Umeå University, Umeå, Sweden
- Wallenberg Center for Molecular Medicine, Umeå University, Umeå, Sweden
- Neuroscience and Physiology, Sahlgrenska Academy, Gothenburg, Sweden
| |
Collapse
|
3
|
Zarrinkoob L, Myrnäs S, Wåhlin A, Eklund A, Malm J. Cerebral Blood Flow Patterns in Patients With Low-Flow Carotid Artery Stenosis, a 4D-PCMRI Assessment. J Magn Reson Imaging 2024. [PMID: 38168876 DOI: 10.1002/jmri.29216] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 12/16/2023] [Accepted: 12/18/2023] [Indexed: 01/05/2024] Open
Abstract
BACKGROUND Compromised cerebral blood flow can contribute to future ischemic events in patients with symptomatic carotid artery disease. However, there is limited knowledge of the effects on cerebral hemodynamics resulting from a reduced internal carotid artery (ICA) blood flow rate (BFR). PURPOSE Investigate how reduced ICA-BFR, relates to BFR in the cerebral arteries. STUDY TYPE Prospective. SUBJECTS Thirty-eight patients, age 72 ± 6 years (11 female). FIELD STRENGTH/SEQUENCE 3-Tesla, four-dimensional phase-contrast magnetic resonance imaging (4D-PCMRI). ASSESSMENT Patients with ischemic stroke or transient ischemic attack were evaluated regarding the degree of stenosis. 4D-PCMRI was used to measure cerebral BFR in 38 patients with symptomatic carotid stenosis (≥50%). BFR in the cerebral arteries was assessed in two subgroups based on symptomatic ICA-BFR: reduced ICA-flow (<160 mL/minutes) and preserved ICA-flow (≥160 mL/minutes). BFR laterality was defined as a difference in the paired ipsilateral-contralateral arteries. STATISTICAL TESTS Patients were grouped based on ICA-BFR (reduced vs. preserved). Statistical tests (independent sample t-test/paired t-test) were used to compare groups and hemispheres. Significance was determined at P < 0.05. RESULTS The degree of stenosis was not significantly different, 80% (95% confidence interval [CI] = 73%-87%) in the reduced ICA-flow vs. 72% (CI = 66%-76%) in the preserved ICA-flow; P = 0.09. In the reduced ICA-flow group, a significantly reduced BFR was found in the ipsilateral middle cerebral artery and anterior cerebral artery (A1), while significantly increased in the contralateral A1. Retrograde BFR was found in the posterior communicating artery and ophthalmic artery. Significant BFR laterality was present in all paired arteries in the reduced ICA-flow group, contrasting the preserved ICA-flow group (P = 0.14-0.93). DATA CONCLUSIONS 4D-PCMRI revealed compromised cerebral BFR due to carotid stenosis, not possible to detect by solely analyzing the degree of stenosis. In patients with reduced ICA-flow, collaterals were not sufficient to maintain symmetrical BFR distribution to the two hemispheres. EVIDENCE LEVEL 2 TECHNICAL EFFICACY: Stage 3.
Collapse
Affiliation(s)
- Laleh Zarrinkoob
- Department of Surgical and Perioperative Sciences, Anesthesiology and Intensive Care Medicine Unit, Umeå University, Umeå, Sweden
| | - Sanne Myrnäs
- Department of Surgical and Perioperative Sciences, Anesthesiology and Intensive Care Medicine Unit, Umeå University, Umeå, Sweden
| | - Anders Wåhlin
- Department of Radiation Sciences, Biomedical Engineering, Umeå University, Umeå, Sweden
- Centre for Biomedical Engineering and Physics, Umeå University, Umeå, Sweden
- Umeå Center for Functional Brain Imaging, Umeå University, Umeå, Sweden
| | - Anders Eklund
- Centre for Biomedical Engineering and Physics, Umeå University, Umeå, Sweden
- Umeå Center for Functional Brain Imaging, Umeå University, Umeå, Sweden
| | - Jan Malm
- Department of Clinical Science, Neurosciences, Umeå University, Umeå, Sweden
| |
Collapse
|
4
|
Kellomäki E, Gu T, Fox AJ, Johansson E. Symptomatic and asymptomatic carotid near-occlusions have very similar angiographic appearance on CT-angiography. Neuroradiology 2022; 64:2203-2206. [PMID: 36129513 PMCID: PMC9576665 DOI: 10.1007/s00234-022-03054-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 09/13/2022] [Indexed: 10/25/2022]
Abstract
The aim of this study was to compare the angiographic appearance of symptomatic and asymptomatic carotid near-occlusion. We have found no such previous study. The study hypothesis was that among symptomatic patients with ≥ 50% carotid stenosis, near-occlusion is more common and near-occlusions are more severe than among asymptomatic persons with ≥ 50% carotid stenosis. We reassessed consecutive CTAs from 4042 persons, 645 had ≥ 50% carotid stenosis, and 385 (60%) symptomatic. Near-occlusion was similarly common in symptomatic (105, 27%) and asymptomatic (56, 24%) cases. Among near-occlusions, the angiographic appearance was very similar between symptomatic and asymptomatic cases: mean stenosis lumen diameter (0.7 mm), distal ICA diameter (2.1 mm), and ECA ratio (0.79) were the same in both groups. Mean ICA ratio (0.46 and 0.48) and share of full collapse was very similar (45% and 42%). These findings add to the pathophysiological understanding of carotid near-occlusion.
Collapse
Affiliation(s)
- Elisa Kellomäki
- Clinical Science, Neurosciences, Umeå University, Umeå, Sweden
| | - Thomas Gu
- Clinical Science, Neurosciences, Umeå University, Umeå, Sweden
| | - Allan J Fox
- Sunnybrook Health Science Centre, University of Toronto, Toronto, ON, Canada
| | - Elias Johansson
- Clinical Science, Neurosciences, Umeå University, Umeå, Sweden. .,Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden.
| |
Collapse
|
5
|
Johansson E, Holmgren M, Henze A, Fox AJ. Diagnosing carotid near-occlusion is a difficult task-but it might get easier. Neuroradiology 2022; 64:1709-1714. [PMID: 35829763 DOI: 10.1007/s00234-022-03007-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 07/02/2022] [Indexed: 11/28/2022]
Affiliation(s)
- Elias Johansson
- Clinical Science, Umeå University, Neurosciences, Umeå, Sweden. .,Wallenberg Center for Molecular Medicine, Umeå University, Umeå, Sweden.
| | | | | | - Allan J Fox
- Sunnybrook Health Science Center, University of Toronto, Toronto, Canada
| |
Collapse
|
6
|
Abstract
Alterations in cerebral blood flow are common in several neurological diseases among the elderly including stroke, cerebral small vessel disease, vascular dementia, and Alzheimer's disease. 4D flow magnetic resonance imaging (MRI) is a relatively new technique to investigate cerebrovascular disease, and makes it possible to obtain time-resolved blood flow measurements of the entire cerebral arterial venous vasculature and can be used to derive a repertoire of hemodynamic biomarkers indicative of cerebrovascular health. The information that can be obtained from one single 4D flow MRI scan allows both the investigation of aberrant flow patterns at a focal location in the vasculature as well as estimations of brain-wide disturbances in blood flow. Such focal and global hemodynamic biomarkers show the potential of being sensitive to impending cerebrovascular disease and disease progression and can also become useful during planning and follow-up of interventions aiming to restore a normal cerebral circulation. Here, we describe 4D flow MRI approaches for analyzing the cerebral vasculature. We then survey key hemodynamic biomarkers that can be reliably assessed using the technique. Finally, we highlight cerebrovascular diseases where one or multiple hemodynamic biomarkers are of central interest.
Collapse
Affiliation(s)
- Anders Wåhlin
- Department of Radiation Sciences, Umeå University, Umeå, Sweden.,Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden.,Umeå Center for Functional Brain Imaging (UFBI), Umeå University, Umeå, Sweden
| | - Anders Eklund
- Department of Radiation Sciences, Umeå University, Umeå, Sweden.,Umeå Center for Functional Brain Imaging (UFBI), Umeå University, Umeå, Sweden
| | - Jan Malm
- Department of Clinical Science and Neurosciences, Umeå University, Umeå, Sweden
| |
Collapse
|
7
|
Johansson E, Gu T, Castillo S, Brunström M, Holsti M, Wanhainen A. Intracerebral Haemorrhage after Revascularisation of Carotid Near Occlusion with Full Collapse. Eur J Vasc Endovasc Surg 2022; 63:523-524. [DOI: 10.1016/j.ejvs.2021.10.057] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 10/18/2021] [Accepted: 10/31/2021] [Indexed: 11/03/2022]
|
8
|
Near-Occlusion is a Common Variant of Carotid Stenosis: Study and Systematic Review. Can J Neurol Sci 2021; 49:55-61. [PMID: 33988097 DOI: 10.1017/cjn.2021.50] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Symptomatic carotid near-occlusion is often described as rare. Recent studies have shown that near-occlusions are overlooked, especially near-occlusion without full collapse (with a small but normal-appearing distal internal carotid artery). OBJECTIVE To assess the prevalence of near-occlusion among symptomatic ≥50% carotid stenosis, incidence of symptomatic near-occlusion, and review the literature. METHODS Prospective controlled single-center cross-sectional study. Consecutive cases with symptomatic ≥50% carotid stenosis were examined with computed tomography angiography (CTA). The CTAs were assessed for near-occlusion by two observers. A systematic literature review was performed with emphasis on how study design affects prevalence estimate. RESULTS Totally, 186 patients with symptomatic ≥50% carotid stenosis were included, 34% (n = 63, 95% CI 27, 41) had near-occlusion. The incidence of symptomatic near-occlusion was 3.4 (95% CI 2.5, 4.2) per 100,000 person-years. Inter-rater κ was 0.71. The average prevalence of near-occlusion among symptomatic ≥50% carotid stenosis was higher in studies with good design (30%, range 27%-34%) than studies without good design (9%, range 2%-10%). CONCLUSIONS Near-occlusion is common variant of symptomatic ≥50% carotid stenosis, both in the current study and in all previous studies of good design. Studies that suggest that near-occlusion is rare have had methodological issues.
Collapse
|
9
|
Defining carotid near-occlusion with full collapse: a pooled analysis. Neuroradiology 2021; 64:59-67. [PMID: 33944975 PMCID: PMC8724220 DOI: 10.1007/s00234-021-02728-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 04/26/2021] [Indexed: 11/21/2022]
Abstract
Purpose Create a new definition of near-occlusion with full collapse to predicting recurrent stroke. Methods Pooled analysis of two studies. Patients with symptomatic ≥ 50% carotid stenoses were included. Outcome was preoperative recurrent ipsilateral ischemic stroke or retinal artery occlusion within 28 days of presenting event. We analyzed several artery diameters on computed tomography angiography and stenosis velocity on ultrasound. Results A total of 430 patients with symptomatic ≥ 50% carotid stenosis were included, 27% had near-occlusion. By traditional definition, 27% with full collapse and 11% without full collapse reached the outcome (p = 0.047). Distal internal carotid artery (ICA) diameter, ICA ratio, and ICA-to-external carotid artery ratio were associated with the outcome. Best new definition of full collapse was distal ICA diameter ≤ 2.0 mm and/or ICA ratio ≤ 0.42. With this new definition, 36% with full collapse and 4% without full collapse reached the outcome (p < 0.001). Conclusions Defining near-occlusion with full collapse as distal ICA diameter ≤ 2.0 mm and/or ICA ratio ≤ 0.42 seems to yield better prognostic discrimination than the traditional appearance-based definition. This novel definition can be used in prognostic and treatment studies of near-occlusion with full collapse.
Collapse
|