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Settecase F, Rayz VL. Advanced vascular imaging techniques. HANDBOOK OF CLINICAL NEUROLOGY 2021; 176:81-105. [DOI: 10.1016/b978-0-444-64034-5.00016-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Li CQ, Hsiao A, Hattangadi-Gluth J, Handwerker J, Farid N. Early Hemodynamic Response Assessment of Stereotactic Radiosurgery for a Cerebral Arteriovenous Malformation Using 4D Flow MRI. AJNR Am J Neuroradiol 2018; 39:678-681. [PMID: 29371257 DOI: 10.3174/ajnr.a5535] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 11/13/2017] [Indexed: 11/07/2022]
Abstract
Brain AVMs treated with stereotactic radiosurgery typically demonstrate a minimum latency period of 1-3 years between treatment and nidus obliteration. Assessment of treatment response is usually limited to evaluation of AVM nidus structural changes using conventional MR imaging and MRA techniques. This report describes the use of 4D Flow MRI to also measure radiation-induced hemodynamic changes in a Spetzler-Martin grade III AVM, which were detectable as early as 6 months after treatment.
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Affiliation(s)
- C Q Li
- From the Department of Radiology (C.Q.L., A.H., J.H., N.F.), University of California, San Diego, San Diego, California
| | - A Hsiao
- From the Department of Radiology (C.Q.L., A.H., J.H., N.F.), University of California, San Diego, San Diego, California
| | - J Hattangadi-Gluth
- Department of Radiation Medicine and Applied Sciences (J.H.-G.), University of California, San Diego, La Jolla, California
| | - J Handwerker
- From the Department of Radiology (C.Q.L., A.H., J.H., N.F.), University of California, San Diego, San Diego, California
| | - N Farid
- From the Department of Radiology (C.Q.L., A.H., J.H., N.F.), University of California, San Diego, San Diego, California
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Schnell S, Ansari SA, Wu C, Garcia J, Murphy IG, Rahman OA, Rahsepar AA, Aristova M, Collins JD, Carr JC, Markl M. Accelerated dual-venc 4D flow MRI for neurovascular applications. J Magn Reson Imaging 2017; 46:102-114. [PMID: 28152256 DOI: 10.1002/jmri.25595] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 11/28/2016] [Indexed: 12/28/2022] Open
Abstract
PURPOSE To improve velocity-to-noise ratio (VNR) and dynamic velocity range of 4D flow magnetic resonance imaging (MRI) by using dual-velocity encoding (dual-venc) with k-t generalized autocalibrating partially parallel acquisition (GRAPPA) acceleration. MATERIALS AND METHODS A dual-venc 4D flow MRI sequence with k-t GRAPPA acceleration was developed using a shared reference scan followed by three-directional low- and high-venc scans (repetition time / echo time / flip angle = 6.1 msec / 3.4 msec / 15°, temporal/spatial resolution = 43.0 msec/1.2 × 1.2 × 1.2 mm3 ). The high-venc data were used to correct for aliasing in the low-venc data, resulting in a single dataset with the favorable VNR of the low-venc but without velocity aliasing. The sequence was validated with a 3T MRI scanner in phantom experiments and applied in 16 volunteers to investigate its feasibility for assessing intracranial hemodynamics (net flow and peak velocity) at the major intracranial vessels. In addition, image quality and image noise were assessed in the in vivo acquisitions. RESULTS All 4D flow MRI scans were acquired successfully with an acquisition time of 20 ± 4 minutes. The shared reference scan reduced the total acquisition time by 12.5% compared to two separate scans. Phantom experiments showed 51.4% reduced noise for dual-venc compared to high-venc and an excellent agreement of velocities (ρ = 0.8, P < 0.001). The volunteer data showed decreased noise in dual-venc data (54.6% lower) compared to high-venc, and improved image quality, as graded by two observers: fewer artifacts (P < 0.0001), improved vessel conspicuity (P < 0.0001), and reduced noise (P < 0.0001). CONCLUSION Dual-venc 4D flow MRI exhibits the superior VNR of the low-venc acquisition and reliably incorporates low- and high-velocity fields simultaneously. In vitro and in vivo data demonstrate improved flow visualization, image quality, and image noise. LEVEL OF EVIDENCE 2 Technical Efficacy: Stage 1 J. MAGN. RESON. IMAGING 2017;46:102-114.
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Affiliation(s)
- Susanne Schnell
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Sameer A Ansari
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.,Department of Neurosurgery, Northwestern University, Chicago, Illinois, USA
| | - Can Wu
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.,Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, Illinois, USA
| | - Julio Garcia
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.,Department of Cardiac Sciences - Stephenson Cardiac Imaging Centre, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Ian G Murphy
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Ozair A Rahman
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Amir A Rahsepar
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Maria Aristova
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Jeremy D Collins
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - James C Carr
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Michael Markl
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.,Department of Neurosurgery, Northwestern University, Chicago, Illinois, USA
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Wu C, Schnell S, Vakil P, Honarmand AR, Ansari SA, Carr J, Markl M, Prabhakaran S. In Vivo Assessment of the Impact of Regional Intracranial Atherosclerotic Lesions on Brain Arterial 3D Hemodynamics. AJNR Am J Neuroradiol 2017; 38:515-522. [PMID: 28057635 DOI: 10.3174/ajnr.a5051] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 10/26/2016] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Intracranial atherosclerosis induces hemodynamic disturbance, which is not well-characterized, particularly in cerebral flow redistribution. We aimed to characterize the impact of regional stenotic lesions on intracranial hemodynamics by using 4D flow MR imaging. MATERIALS AND METHODS 4D flow MR imaging was performed in 22 symptomatic patients (mean age, 68.4 ± 14.2 years) with intracranial stenosis (ICA, n = 7; MCA, n = 9; basilar artery, n = 6) and 10 age-appropriate healthy volunteers (mean age, 60.7 ± 8.1 years). 3D blood flow patterns were visualized by using time-integrated pathlines. Blood flow and peak velocity asymmetry indices were compared between patients and healthy volunteers in 4 prespecified arteries: ICAs, MCAs, and anterior/posterior cerebral arteries. RESULTS 3D blood flow pathlines demonstrated flow redistribution across cerebral arteries in patients with unilateral intracranial stenosis. For patients with ICA stenosis compared with healthy volunteers, significantly lower flow and peak velocities were identified in the ipsilateral ICA (P = .001 and P = .001) and MCA (P < .001 and P = .001), but higher flow, in the ipsilateral PCA (P < .001). For patients with MCA stenosis, significantly lower flow and peak velocities were observed in the ipsilateral ICA (P = .009 and P = .045) and MCA (P < .001 and P = .005), but significantly higher flow was found in the ipsilateral posterior cerebral artery (P = .014) and anterior cerebral artery (P = .006). The asymmetry indices were not significantly different between patients with basilar artery stenosis and the healthy volunteers. CONCLUSIONS Regional intracranial atherosclerotic lesions not only alter distal arterial flow but also significantly affect ipsilateral collateral arterial hemodynamics.
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Affiliation(s)
- C Wu
- From the Department of Biomedical Engineering (C.W., M.M.), McCormick School of Engineering, Northwestern University, Chicago, Illinois .,Departments of Radiology (C.W., S.S., P.V., A.R.H., S.A.A., J.C., M.M.).,Philips Healthcare (C.W.), Gainesville, Florida
| | - S Schnell
- Departments of Radiology (C.W., S.S., P.V., A.R.H., S.A.A., J.C., M.M.)
| | - P Vakil
- Departments of Radiology (C.W., S.S., P.V., A.R.H., S.A.A., J.C., M.M.)
| | - A R Honarmand
- Departments of Radiology (C.W., S.S., P.V., A.R.H., S.A.A., J.C., M.M.)
| | - S A Ansari
- Departments of Radiology (C.W., S.S., P.V., A.R.H., S.A.A., J.C., M.M.).,Neurological Surgery (S.A.A.)
| | - J Carr
- Departments of Radiology (C.W., S.S., P.V., A.R.H., S.A.A., J.C., M.M.)
| | - M Markl
- From the Department of Biomedical Engineering (C.W., M.M.), McCormick School of Engineering, Northwestern University, Chicago, Illinois.,Departments of Radiology (C.W., S.S., P.V., A.R.H., S.A.A., J.C., M.M.)
| | - S Prabhakaran
- Neurology (S.P.), Feinberg School of Medicine, Northwestern University, Chicago, Illinois
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Automatic Liver Segmentation from CT Images Using Single-Block Linear Detection. BIOMED RESEARCH INTERNATIONAL 2016; 2016:9420148. [PMID: 27631012 PMCID: PMC5008026 DOI: 10.1155/2016/9420148] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 06/22/2016] [Accepted: 07/26/2016] [Indexed: 12/30/2022]
Abstract
Automatic liver segmentation not only plays an important role in the analysis of liver disease, but also reduces the cost and humanity's impact in segmentation. In addition, liver segmentation is a very challenging task due to countless anatomical variations and technical difficulties. Many methods have been designed to overcome these challenges, but these methods still need to be improved to obtain the desired segmentation precision. In this paper, a fast algorithm is proposed for liver extraction from CT images with single-block linear detection. The proposed method does not require iteration; thus, the computational time and complexity are decreased enormously. In addition, the initialization is not crucial in the algorithm, so the algorithm's robustness and specificity are improved. The experimental evaluation of the proposed method revealed effective segmentation in normal and abnormal (liver hemangioma and liver cancer) abdominal CT images. The average sensitivity, accuracy, and specificity for liver cancer are 96.59%, 98.65%, and 99.03%, respectively. The results of image segmentation approximate the manual segmentation results by the technical doctor. Moreover, our method shows superior flexibility to newly published method with comparable performance. The advantage of our method is verified with experimental results, which is described in detail.
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Schnell S, Wu C, Ansari SA. Four-dimensional MRI flow examinations in cerebral and extracerebral vessels - ready for clinical routine? Curr Opin Neurol 2016; 29:419-28. [PMID: 27262148 PMCID: PMC4939804 DOI: 10.1097/wco.0000000000000341] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
PURPOSE OF REVIEW To evaluate the feasibility of 4-dimensional (4D) flow MRI for the clinical assessment of cerebral and extracerebral vascular hemodynamics in patients with neurovascular disease. RECENT FINDINGS 4D flow MRI has been applied in multiple studies to qualitatively and quantitatively study intracranial aneurysm blood flow for potential risk stratification and to assess treatment efficacy of various neurovascular lesions, including intraaneurysmal and parent artery blood flow after flow diverter stent placement and staged embolizations of arteriovenous malformations and vein of Galen aneurysmal malformations. Recently, the technique has been utilized to characterize age-related changes of normal cerebral hemodynamics in healthy individuals over a broad age range. SUMMARY 4D flow MRI is a useful tool for the noninvasive, volumetric and quantitative hemodynamic assessment of neurovascular disease without the need for gadolinium contrast agents. Further improvements are warranted to overcome technical limitations before broader clinical implementation. Current developments, such as advanced acceleration techniques (parallel imaging and compressed sensing) for faster data acquisition, dual or multiple velocity encoding strategies for more accurate arterial and venous flow quantification, ultrahigh-field strengths to achieve higher spatial resolution and streamlined postprocessing workflow for more efficient and standardized flow analysis, are promising advancements in 4D flow MRI.
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Affiliation(s)
- Susanne Schnell
- Dept. of Radiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - Can Wu
- Dept. of Radiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois
- Dept. of Biomedical Engineering, Northwestern University, Evanston, Illinois
| | - Sameer A. Ansari
- Dept. of Radiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois
- Dept. of Neurology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois
- Dept. of Neurological Surgery, Northwestern University, Feinberg School of Medicine, Chicago, Illinois
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Turski P, Scarano A, Hartman E, Clark Z, Schubert T, Rivera L, Wu Y, Wieben O, Johnson K. Neurovascular 4DFlow MRI (Phase Contrast MRA): emerging clinical applications. ACTA ACUST UNITED AC 2016. [DOI: 10.1186/s40809-016-0019-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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