Optimization of the Image Contrast for the Developing Fetal Brain using 3D Radial VIBE Sequence in 3T Magnetic Resonance Imaging

Abstract Background: Faster and motion robust magnetic resonance imaging (MRI) sequences are desirable in fetal brain MRI. T1-weighted images are essential for evaluating fetal brain development. We optimized the radial volumetric interpolated breath-hold examination (VIBE) sequence for qualitative T1-weighted images of the fetal brain with improved image contrast and reduced motion sensitivity. Materials and Methods: This was an institutional review board-approved prospective study. Thirty-two pregnant subjects underwent fetal brain scan at 3 Tesla MRI. T1-weighted images were acquired using a 3D radial VIBE sequence with flip angles of 6º, 9º, 12º, and 15º and turbo FLASH (TFL) sequence. Qualitative assessments including image quality and motion artifact severity were evaluated. The image contrast ratio between gray and white matter were measured. Interobserver reliability and intraobserver repeatability were assessed using intraclass correlation coefficient (ICC).Results: Interobserver reliability and intraobserver repeatability universally revealed almost perfect agreement (ICC > 0.800). Significant differences in image quality were detected in basal ganglia (P < 0.001), central sulcus (P = 0.005), myelination (P < 0.001), lateral fissure (P = 0.008), optic chiasm (P < 0.001), and gray matter (P < 0.001) among radial VIBE with flip angles 6º, 9º, 12º, 15º and TFL groups. Image quality at the 9º flip angle in radial VIBE was generally better than TFL. Radial VIBE sequence with 9º flip angle of gray matter was significantly different by gestational age (GA) before and after 28 weeks (P = 0.036). Quantified image contrast was significantly different among protocols, consistent with qualitative analysis of image quality.Conclusions: Three-dimensional radial VIBE with 9º flip angle provides optimal, stable T1-weighted images of the fetal brain. Fetal brain structure and development can be evaluated using high-quality images obtained using this angle.

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Dynamic Imaging of Perfusion and Oxygenation by Functional Magnetic Resonance Imaging

Journal of Cerebral Blood Flow & Metabolism ◽

10.1097/01.wcb.0000141501.12558.9b ◽

2004 ◽

Vol 24 (12) ◽

pp. 1369-1381 ◽

Cited By ~ 15

Author(s):

Kida Ikuhiro ◽

K. Maciejewski Paul ◽

Fahmeed Hyder

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Functional Mri ◽

Dynamic Imaging ◽

Flip Angle ◽

Image Contrast ◽

Laser Doppler ◽

Resonance Imaging ◽

Tissue Water ◽

Dynamic Changes

Cerebral blood flow can be measured with magnetic resonance imaging (MRI) by arterial spin labeling techniques, where magnetic labeling of flowing spins in arterial blood water functions as the endogenous tracer upon mixing with the unlabeled stationary spins of tissue water. The consequence is that the apparent longitudinal relaxation time (T1) of tissue water is attenuated. A modified functional MRI scheme for dynamic CBF measurement is proposed that depends on extraction of T1 weighting from the blood oxygenation level–dependent (BOLD) image contrast, because the functional MRI signal also has an intrinsic T1 weighting that can be altered by variations of the excitation flip angle. In the α-chloralose-anesthetized rat model at 7T, the authors show that the stimulation-induced BOLD signal change measured with two different flip angles can be combined to obtain a T1-weighted MRI signal, reflecting the magnitude of the CBF change, which can be deconvolved to obtain dynamic changes in CBF. The deconvolution of the T1-weighted MRI signal, which is a necessary step for accurate reflection of the dynamic changes in CBF, was made possible by a transfer function obtained from parallel laser-Doppler flowmetry experiments. For all stimulus durations (ranging from 4 to 32 seconds), the peak CBF response measured by MRI after the deconvolution was reached at 4.5 ± 1.0 seconds, which is in good agreement with (present and prior) laser-Doppler measurements. Because the low flip angle data can also provide dynamic changes of the conventional BOLD image contrast, this method can be used for simultaneous imaging of CBF and BOLD dynamics.

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Faculty Opinions recommendation of Magnetic resonance imaging of the prostate at 1.5 versus 3.0T: A prospective comparison study of image quality.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.727719412.793549259 ◽

2018 ◽

Author(s):

Ardeshir Rastinehad

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Image Quality ◽

Comparison Study ◽

Resonance Imaging ◽

Prospective Comparison

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The Kaplan Fibers of the Iliotibial Band Can Be Identified on Routine Knee Magnetic Resonance Imaging

The American Journal of Sports Medicine ◽

10.1177/0363546519868219 ◽

2019 ◽

Vol 47 (12) ◽

pp. 2895-2903 ◽

Cited By ~ 5

Author(s):

Lachlan Batty ◽

Jerome Murgier ◽

Richard O’Sullivan ◽

Kate E. Webster ◽

Julian A. Feller ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Sagittal Plane ◽

Interobserver Reliability ◽

Joint Line ◽

Coronal Plane ◽

Iliotibial Band ◽

Resonance Imaging ◽

Lateral Gastrocnemius ◽

The Mean

Background: The Kaplan fibers (KFs) of the iliotibial band have been suggested to play a role in anterolateral rotational instability of the knee, particularly in the setting of an anterior cruciate ligament (ACL) rupture. Description of the normal magnetic resonance imaging (MRI) anatomy of the KFs may facilitate subsequent investigation into the MRI signs of injury. Purpose: To assess if the KF complex can be identified on 3-T MRI using standard knee protocols. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: 3-T MRI scans of 50 ACL-intact knees were reviewed independently by a musculoskeletal radiologist and 2 orthopaedic surgeons. Identification of the KFs was based on radiological diagnostic criteria developed a priori. Identification of the KFs in the sagittal, coronal, and axial planes was recorded. Interobserver reliability was assessed using the Kappa statistic. Detailed anatomy including distance to the joint line and relationship to adjacent structures was recorded. Results: The mean patient age was 43 years (range, 15-81 years), 58% were male, and 50% were right knees. The KFs were identified by at least 2 reviewers on the sagittal images in 96% of cases, on the axial images in 76% of cases, and on the coronal images in 4% of cases. The mean distance from the KF distal femoral insertion to the lateral joint line was 50.1 mm (SD, 6.6 mm) and the mean distance to the lateral gastrocnemius tendon origin was 10.8 mm (SD, 8.6 mm). The KFs were consistently identified immediately anterior to the superior lateral geniculate artery on sagittal imaging. Interobserver reliability for identification was best in the sagittal plane (Kappa 0.5) and worst in the coronal plane (Kappa 0.1). Conclusion: The KF complex can be identified on routine MRI sequences in the ACL-intact knee; however, there is low to moderate interobserver reliability. Imaging in the sagittal plane had the highest rate of identification and the coronal plane the lowest. There is a consistent relationship between the most distal KF femoral attachment and the lateral joint line, lateral gastrocnemius tendon, and superior lateral geniculate artery.

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