Velocity measurement of microvessels using phase‐contrast magnetic resonance angiography at 7 tesla MRI

Kang, Chang-Ki; Park, Chan-A; Lee, David I.; Lee, Yeong-Bae; Park, Cheol-Wan; Kim, Young-Bo; Cho, Zang-Hee

doi:10.1002/mrm.25600

Cited by 27 publications

(26 citation statements)

References 31 publications

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“…Moreover, 3D image reconstruction of CTAs is a more effective means of classifying morphological variations of the ICA and for detecting ICA abnormalities; therefore, this method can be used to reduce the risk of serious complications during neck surgery 85 , 86 . In addition to CTA, MRA is another useful non-invasive method for diagnosing DICAs 87 . For instance, Tomiya et al (1995) performed MRA in 13 patients with DICAs and obtained very clear images of ICA tortuosity.…”

Section: Image Examinationmentioning

confidence: 99%

Current Understanding of Dolichoarteriopathies of the Internal Carotid Artery: A Review

et al. 2017

Int. J. Med. Sci.

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Dolichoarteriopathies of the internal carotid artery (DICAs) are not uncommon, and although several studies have investigated DICAs, several questions regarding the etiology and best management course for DICAs remain unanswered. It is also difficult to correlate the occurrence of DICAs with the onset of clinical symptoms. Therefore, we surveyed the literature in PubMed and performed a review of DICAs to offer a comprehensive picture of our understanding of DICAs. We found that DICAs can be classified into three types, specifically tortuous, coiling and kinking, and are not associated with atherosclerotic risk factors. Cerebral hemodynamic changes are mainly associated with the degree of bending of DICAs. DICAs can result in symptoms of the brain and eyes due to insufficient blood supply and can co-occur with a pulsatile cervical mass, a pharyngeal bulge and pulsation. The diagnostic tools for the assessment of DICAs include Doppler ultrasonography, computed tomography angiography (CTA), magnetic resonance angiography (MRA) and digital subtraction angiography (DSA), and although DSA remains the gold standard, Doppler ultrasonography is a convenient method that provides useful data for the morphological evaluation of DICAs. CTA and MRA are efficient methods for detecting the morphology of the cervical segment of DICAs. Some DICAs should be treated surgically based on certain indications, and several methods, including correcting the bending or shortening of DICAs, have been developed for the treatment of DICAs. The appropriate treatment of DICAs results in good outcomes and is associated with low morbidity and mortality rates. However, despite the success of surgical reconstruction, an appropriate therapeutic treatment remains a subject of numerous debates due to the lack of multicentric, randomized, prospective studies.

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Section: Image Examinationmentioning

confidence: 99%

Current Understanding of Dolichoarteriopathies of the Internal Carotid Artery: A Review

et al. 2017

Int. J. Med. Sci.

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“…A recent ultra-high field study focused on the velocity profile and related pulsatility of the collection of (basal ganglia and semiovale center) perforating arteries in young volunteers, but not individual LSAs and the intracerebral pulse damping effect (Bouvy et al, 2016 ). Another recent study nicely visualized the velocity and direction of the blood flow averaged over the cardiac cycle in the circle of Willis, major cerebral arteries and LSA in young subjects (Kang et al, 2016 ). In the current study we focus on the dynamic wave form features (pulsatility and damping) of the flow through the LSA and MCA and on the quality (reproducibility and effect size) of the MRI measurement.…”

Section: Introductionmentioning

confidence: 99%

Pulsatility of Lenticulostriate Arteries Assessed by 7 Tesla Flow MRI—Measurement, Reproducibility, and Applicability to Aging Effect

et al. 2017

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Characterization of flow properties in cerebral arteries with 1.5 and 3 Tesla MRI is usually limited to large cerebral arteries and difficult to evaluate in the small perforating arteries due to insufficient spatial resolution. In this study, we assessed the feasibility to measure blood flow waveforms in the small lenticulostriate arteries with 7 Tesla velocity-sensitive MRI. The middle cerebral artery was included as reference. Imaging was performed in five young and five old healthy volunteers. Flow was calculated by integrating time-varying velocity values over the vascular cross-section. MRI acquisitions were performed twice in each subject to determine reproducibility. From the flow waveforms, the pulsatility index and damping factor were deduced. Reproducibility values, in terms of the intraclass correlation coefficients, were found to be good to excellent. Measured pulsatility index of the lenticulostriate arteries significantly increased and damping factor significantly decreased with age. In conclusion, we demonstrate that blood flow through the lenticostriate arteries can be precisely measured using 7 Tesla MRI and reveal effects of arterial stiffness due to aging. These findings hold promise to provide relevant insights into the pathologies involving perforating cerebral arteries.

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“…However, there is need for more MRA studies [especially utilizing UHF MRI] [19, 60, 73–77]. Non-invasive methods like nCE MRA, TOF, SWI, and diffusion related methods have very high potential in safe, non-radiation, nCE detection of high-signal-intensity plaque, coronary arterial wall [69], and atherosclerotic vascular disease [83, 84] as well as in a host of other indications [19, 60, 65–70, 73, 74, 85]. UHF 7T imaging can alleviate and overcome several imaging challenges encountered in neurovascular disease at lower field strengths [1.5T and 3T] like venous contamination obscuring underlying arterial architecture or delineation of contextual anatomical structures [65].…”

Section: Discussionmentioning

confidence: 99%

Ultra-high field upper extremity peripheral nerve and non-contrast enhanced vascular imaging

et al. 2017

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ObjectiveThe purpose of this study was to explore the efficacy of Ultra-high field [UHF] 7 Tesla [T] MRI as compared to 3T MRI in non-contrast enhanced [nCE] imaging of structural anatomy in the elbow, forearm, and hand [upper extremity].Materials and methodA wide range of sequences including T1 weighted [T1] volumetric interpolate breath-hold exam [VIBE], T2 weighted [T2] double-echo steady state [DESS], susceptibility weighted imaging [SWI], time-of-flight [TOF], diffusion tensor imaging [DTI], and diffusion spectrum imaging [DSI] were optimized and incorporated with a radiofrequency [RF] coil system composed of a transverse electromagnetic [TEM] transmit coil combined with an 8-channel receive-only array for 7T upper extremity [UE] imaging. In addition, Siemens optimized protocol/sequences were used on a 3T scanner and the resulting images from T1 VIBE and T2 DESS were compared to that obtained at 7T qualitatively and quantitatively [SWI was only qualitatively compared]. DSI studio was utilized to identify nerves based on analysis of diffusion weighted derived fractional anisotropy images. Images of forearm vasculature were extracted using a paint grow manual segmentation method based on MIPAV [Medical Image Processing, Analysis, and Visualization].ResultsHigh resolution and high quality signal-to-noise ratio [SNR] and contrast-to-noise ratio [CNR]—images of the hand, forearm, and elbow were acquired with nearly homogeneous 7T excitation. Measured [performed on the T1 VIBE and T2 DESS sequences] SNR and CNR values were almost doubled at 7T vs. 3T. Cartilage, synovial fluid and tendon structures could be seen with higher clarity in the 7T T1 and T2 weighted images. SWI allowed high resolution and better quality imaging of large and medium sized arteries and veins, capillary networks and arteriovenous anastomoses at 7T when compared to 3T. 7T diffusion weighted sequence [not performed at 3T] demonstrates that the forearm nerves are clearly delineated by fiber tractography. The proper digital palmar arteries and superficial palmar arch could also be clearly visualized using TOF nCE 7T MRI.ConclusionUltra-high resolution neurovascular imaging in upper extremities is possible at 7T without use of renal toxic intravenous contrast. 7T MRI can provide superior peripheral nerve [based on fiber anisotropy and diffusion coefficient parameters derived from diffusion tensor/spectrum imaging] and vascular [nCE MRA and vessel segmentation] imaging.

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Velocity measurement of microvessels using phase‐contrast magnetic resonance angiography at 7 tesla MRI

Abstract: This study demonstrated the potential for measuring the velocity and direction of blood flow in the targeted microvessels using an appropriate VENC and 7T MRI.

Cited by 27 publications

References 31 publications

Current Understanding of Dolichoarteriopathies of the Internal Carotid Artery: A Review

Current Understanding of Dolichoarteriopathies of the Internal Carotid Artery: A Review

Pulsatility of Lenticulostriate Arteries Assessed by 7 Tesla Flow MRI—Measurement, Reproducibility, and Applicability to Aging Effect

Ultra-high field upper extremity peripheral nerve and non-contrast enhanced vascular imaging

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