The need for phase‐encoding flow compensation in high‐resolution intracranial magnetic resonance angiography

Parker, Dennis L.; Goodrich, K. Craig; Roberts, John A.; Chapman, Brian E.; Jeong, Eun Kee; Kim, Seong Eun; Tsuruda, Jay S.; Katzman, Gregory L.

doi:10.1002/jmri.10322

Cited by 22 publications

(25 citation statements)

References 17 publications

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“…MRA screening was performed by using a three-dimensional time-offlight MRA technique to visualize the base of the brain to above the circle of Willis and including all major intracranial branches. A specially designed head coil, providing substantial image improvement, was used, allowing identification of intracranial aneurysms down to the size of 2 mm (Parker et al 2000(Parker et al , 2003. All images were reviewed independently by two investigators for the presence of IA.…”

Section: Subjectsmentioning

confidence: 99%

Confirmation of chromosome 7q11 locus for predisposition to intracranial aneurysm

et al. 2004

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A significant linkage of intracranial aneurysm (IA) has recently been reported to chromosomal region 7q11 (MLS=3.22) in a genomic search of 85 Japanese nuclear families with at least two affected siblings (104 sib pairs). This region contains the elastin gene (ELN, OMIM 130160), which is a functional candidate gene for IA. We have replicated this finding through linkage analyses in 13 extended pedigrees from Utah, comprising 39 IA cases. We genotyped three markers flanking ELN and performed two-point and multipoint parametric analyses, employing simple dominant and recessive models. Analyses utilizing a recessive affecteds-only model yielded significant confirmation of linkage to the region (best evidence, multipoint TLOD=2.34, at D7S2421, corrected P=0.001). This study is the first to confirm the linkage of the 7q11 locus for IA.

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Section: Subjectsmentioning

confidence: 99%

Confirmation of chromosome 7q11 locus for predisposition to intracranial aneurysm

et al. 2004

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“…Differences in resolution may affect the tortuosity measure. Some vessels visible in MRA images from high 7.0 T field strengths may not be seen at lower resolution and the high field may cause phase flow artifacts [13,14] that can be mistaken for arteries by centerline algorithms, requiring pre- or post-processing for removal. Filtering can cause data loss and could affect the tortuosity measure.…”

Section: Introductionmentioning

confidence: 99%

Validation of an arterial tortuosity measure with application to hypertension collection of clinical hypertensive patients

et al. 2011

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BackgroundHypertension may increase tortuosity or twistedness of arteries. We applied a centerline extraction algorithm and tortuosity metric to magnetic resonance angiography (MRA) brain images to quantitatively measure the tortuosity of arterial vessel centerlines. The most commonly used arterial tortuosity measure is the distance factor metric (DFM). This study tested a DFM based measurement’s ability to detect increases in arterial tortuosity of hypertensives using existing images. Existing images presented challenges such as different resolutions which may affect the tortuosity measurement, different depths of the area imaged, and different artifacts of imaging that require filtering.MethodsThe stability and accuracy of alternative centerline algorithms was validated in numerically generated models and test brain MRA data. Existing images were gathered from previous studies and clinical medical systems by manually reading electronic medical records to identify hypertensives and negatives. Images of different resolutions were interpolated to similar resolutions. Arterial tortuosity in MRA images was measured from a DFM curve and tested on numerically generated models as well as MRA images from two hypertensive and three negative control populations. Comparisons were made between different resolutions, different filters, hypertensives versus negatives, and different negative controls.ResultsIn tests using numerical models of a simple helix, the measured tortuosity increased as expected with more tightly coiled helices. Interpolation reduced resolution-dependent differences in measured tortuosity. The Korean hypertensive population had significantly higher arterial tortuosity than its corresponding negative control population across multiple arteries. In addition one negative control population of different ethnicity had significantly less arterial tortuosity than the other two.ConclusionsTortuosity can be compared between images of different resolutions by interpolating from lower to higher resolutions. Use of a universal negative control was not possible in this study. The method described here detected elevated arterial tortuosity in a hypertensive population compared to the negative control population and can be used to study this relation in other populations.

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“…7 Spins in a voxel at bifurcation or bending portions of vessels are likely to have greater components of incoherent motion. 8,9 In the ‰ow dephasing gradient, b-values at zero frequency (k＝0) for 2-and 3-axis GMN sequences were almost the same and below 0.01 s/mm 2 , whereas those at the maximum frequency (k＝128) were 0.05 and 0.1 s/mm 2 . In the present study, we examined the images obtained when we applied GMN to 2 and 3 axes in phantom and clinical studies.…”

Section: Methodsmentioning

confidence: 97%

“…As a result, the ‰ow void seemed to be more prominent in the sequence with GMN applied to 3 axes than to 2 axes. 8,9 The calculation of b-value showed that dispersion in the phase encoding on the 3-axis GMN sequence was twice that on the 2-axis GMN sequence. Therefore, the signal magnitude of such voxels on the 3-axis GMN was reduced to a greater extent than on the 2-axis GMN sequence.…”

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confidence: 99%

Improved Visualization of Intracranial Vessels by Gradient Moment Nulling in Hybrid of Opposite-contrast Magnetic Resonance Angiography (HOP MRA)

Azuma

Kodama

Yokota

et al. 2010

MRMS

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Hybrid of opposite-contrast (HOP) magnetic resonance angiography (MRA) is a new method that combines the advantages of 3-dimensional (3D) time-of-‰ight (TOF) MRA and black-blood (BB) MRA without prolonging acquisition time. In phantom and clinical studies, we focused on image diŠerences when we applied gradient moment nulling (GMN) to 2 or 3 axes in theˆrst echo. We made an original phantom with a semicircular tube of 3-and 5-mm internal diameter, with ‰ow rate in the tube of 0, 20, 60, 80, or 120 cm/s. In original images of the phantom obtained with TOF MRA and ‰ow-sensitive BB MRA and inˆlter frequency-weighted subtraction (FWS) processed images acquired with HOP MRA, we measured the contrast-to-noise ratio (CNR) of both the inside and outside of the tubes. In FWS processed images with GMN applied to 2 axes, the CNR was high at various ‰ow rates in both straight and bending portions of the tubes in comparison with TOF images. In a clinical study in 15 patients, we evaluated vessel visualization in images obtained using conventional TOF MRA with magnetization transfer contrast (MTC) and HOP MRA. In clinical studies, visualization scores of HOP MRA were equivalent to those of conventional TOF MRA in the bilateral internal carotid arteries (ICA) and inferior in the basilar arteries. However, visualization of the peripheral portion of the middle cerebral artery (MCA) improved signiˆcantly in HOP MRA with GMN applied to 2 and 3 axes. Visualization of the main trunk of the ICA and MCA was superior in HOP MRA with GMN applied to 2 axes. HOP MRA with 2-axis GMN may be useful for excellent visualization of both major arteries and peripheral vessels in the head.

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The need for phase‐encoding flow compensation in high‐resolution intracranial magnetic resonance angiography

Cited by 22 publications

References 17 publications

Confirmation of chromosome 7q11 locus for predisposition to intracranial aneurysm

Confirmation of chromosome 7q11 locus for predisposition to intracranial aneurysm

Validation of an arterial tortuosity measure with application to hypertension collection of clinical hypertensive patients

Improved Visualization of Intracranial Vessels by Gradient Moment Nulling in Hybrid of Opposite-contrast Magnetic Resonance Angiography (HOP MRA)

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