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Kan H, Mizuno K, Takizawa M, Shimohira M, Kawai T, Aoki T, Tsubokura S, Kasai H. Noncontrast time-resolved pulmonary magnetic resonance angiography with consecutive beam saturation pulse and variable flip angles using three-dimensional fast spin echo: A preliminary study. Magn Reson Imaging 2022; 94:80-88. [PMID: 36122676 DOI: 10.1016/j.mri.2022.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 08/20/2022] [Accepted: 09/13/2022] [Indexed: 11/16/2022]
Abstract
To develop and validate a novel noncontrast time-resolved magnetic resonance angiography (NC TR-MRA) using consecutive beam pulses with variable flip angles for visualizing hemodynamics in the pulmonary artery, we performed phantom and volunteer studies and applied the novel NC TR-MRA to a 51-year-old woman with pulmonary arteriovenous malformation (PAVM).The novel NC TR-MRA sequence utilized consecutive multiple-beam saturation pulses with variable flip angles considering venous blood T1 relaxation to alter the visualized blood signal length. The flowing blood signal length is suppressed according to the number of beam saturation pulses. NC TR-MRA in each flow phase was assessed by subtracting the images with and without beam saturation pulses. In the flow phantom study, three flow velocities were used to simulate physiological pulmonary arterial blood flow. Signal profiles along the flow direction were evaluated in each flow phase. In the volunteer study, five healthy volunteers were recruited, and NC TR-MRA was applied to evaluate relationships between the flow-saturated time and signal enhancement rates. Four regions of interest (ROIs) were determined on the proximal and distal portions of the right basal artery. A patient with PAVM was included to validate whether a PAVM lesion could be visualized using NC TR-MRA. The visualized flow signal lengths extended proportionally with the number of beam saturation pulses in the steady-flow phantom at all velocities. In the volunteer study, NC TR-MRA images showed signal enhancement from the proximal to distal portions of the right basal artery with increase in the flow-saturated time. Signal enhancement rates in all ROIs were significantly positively correlated with the flow-saturated time (p < 0.001 in all ROIs). Further, the lesion and its hemodynamics could be explicitly visualized in the patient with PAVM. Hence, NC TR-MRA using beam saturation pulse can visualize the hemodynamics of the pulmonary artery and may be useful for diagnosing and following patients with PAVM.
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Affiliation(s)
- Hirohito Kan
- Department of Integrated Health Sciences, Nagoya University Graduate School of Medicine, 1-1-20, Daiko-Minami, Higashi-ku, Nagoya, Aichi 461-8673, Japan; Department of Radiology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-ku, Nagoya, Aichi 467-8601, Japan.
| | - Kyosuke Mizuno
- Department of Radiology, Nagoya City University Hospital, 1 Kawasumi, Mizuho-ku, Nagoya, Aichi 467-8601, Japan.
| | - Masahiro Takizawa
- FUJIFILM Healthcare Corporation, 2-1, Shintoyofuta, Kashiwa, Chiba, 277-0804, Japan..
| | - Masashi Shimohira
- Department of Radiology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-ku, Nagoya, Aichi 467-8601, Japan.
| | - Tatsuya Kawai
- Department of Radiology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-ku, Nagoya, Aichi 467-8601, Japan.
| | - Toshitaka Aoki
- Department of Radiology, Nagoya City University Hospital, 1 Kawasumi, Mizuho-ku, Nagoya, Aichi 467-8601, Japan.
| | - Satoshi Tsubokura
- Department of Radiology, Nagoya City University Hospital, 1 Kawasumi, Mizuho-ku, Nagoya, Aichi 467-8601, Japan.
| | - Harumasa Kasai
- Department of Radiology, Nagoya City University Hospital, 1 Kawasumi, Mizuho-ku, Nagoya, Aichi 467-8601, Japan.
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Giron A, Cox C, MacKay B. Techniques for Imaging Vascular Supply of Peripheral Nerves. J Brachial Plex Peripher Nerve Inj 2021; 16:e24-e30. [PMID: 34316297 PMCID: PMC8302262 DOI: 10.1055/s-0041-1731280] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 03/31/2021] [Indexed: 11/23/2022] Open
Abstract
Few studies have been developed to map the vascular structures feeding peripheral nerves, with the majority using cadaveric models and inadequate sample sizes. Preliminary evidence, while limited, indicates that the mapping of these vessels may allow or preclude certain procedures in nerve reconstruction due to the location of essential arterial inflow to the vasa nervorum. This review evaluates the evidence regarding historical, current, and emerging techniques for visualizing these vascular structures in vivo and considers their potential application in peripheral nerve vasculature.
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Affiliation(s)
- Alec Giron
- Department of Orthopaedic Surgery, Texas Tech University Health Sciences Center School of Medicine Lubbock, Texas Tech University Health Sciences Center School of Medicine, Lubbock, Texas, United Sates
| | - Cameron Cox
- Department of Orthopaedic Surgery, Texas Tech University Health Sciences Center, Lubbock, Texas, United States
| | - Brendan MacKay
- Department of Orthopaedic Surgery, Texas Tech Health Sciences Center, Lubbock, Texas, United Sates
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Kilburg C, Scott McNally J, de Havenon A, Taussky P, Kalani MYS, Park MS. Advanced imaging in acute ischemic stroke. Neurosurg Focus 2017; 42:E10. [DOI: 10.3171/2017.1.focus16503] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The evaluation and management of acute ischemic stroke has primarily relied on the use of conventional CT and MRI techniques as well as lumen imaging sequences such as CT angiography (CTA) and MR angiography (MRA). Several newer or less-established imaging modalities, including vessel wall MRI, transcranial Doppler ultrasonography, and 4D CTA and MRA, are being developed to complement conventional CT and MRI techniques. Vessel wall MRI provides high-resolution analysis of both extracranial and intracranial vasculature to help identify previously occult lesions or characteristics of lesions that may portend a worse natural history. Transcranial Doppler ultrasonography can be used in the acute setting as a minimally invasive way of identifying large vessel occlusions or monitoring the response to stroke treatment. It can also be used to assist in the workup for cryptogenic stroke or to diagnose a patent foramen ovale. Four-dimensional CTA and MRA provide a less invasive alternative to digital subtraction angiography to determine the extent of the clot burden and the degree of collateral blood flow in large vessel occlusions. Along with technological advances, these new imaging modalities are improving the diagnosis, workup, and management of acute ischemic stroke— roles that will continue to expand in the future.
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