The Fast Spoiled Gradient Echo (FSPGR) sequence is often used in MRI to create T1-weighted images. The signal intensity generated by this sequence depends on the applied flip angle. Knowing the correct flip angle is essential for the determination of T1-maps by means of an FSPGR based Variable Flip Angle (VFA) approach. Also, quantitatively determining the concentration of contrast agent in case of Dynamic Contrast Enhanced MRI (DCE-MRI) requires knowledge of the applied flip angle. In both cases, the B1-field (in)homogeneity significantly affects the results. In this paper, we present a new method to obtain both the T1-map and B1-inhomogeneity map using scans that can each be acquired within a breath-hold. We combine two short sequences for T1 quantification: Variable Flip Angle and Look-Locker (LL). The T1-maps obtained from the LL data were used to estimate the B1-inhomogeneity inherently present in the VFA data, which was then used to correct for the VFA method's inaccurate flip angles. This way, a reliable T1-map could be computed, which was validated using both in vitro and in vivo scans. The in vitro results show that the procedure yields a substantially smaller mean deviation in T1 from the T1 measurement's gold standard (the Inversion Recovery method), while the in vivo results show both a more accurate estimation of T1 and a reduction of the influence of the B1-inhomogeneity on the signal intensity.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/j.mri.2014.10.008 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Modified Trochanteric Flip Osteotomy in Varus Intertrochanteric Osteotomy for Treatment of Legg-Calvé-Perthes Disease.
Children (Basel)
January 2025
Pediatric Orthopedics, Deformity Reconstruction and Foot Surgery, University Hospital Muenster, 48149 Muenster, Germany.
: Legg-Calvé-Perthes disease (LCPD) presents challenges in treatment due to its varied course and unclear etiology. This study aimed to evaluate the efficacy of combining proximal femoral varus osteotomy (PFVO) with a modified trochanteric flip osteotomy to address biomechanical consequences and improve hip abductor muscle strength. : We present a modified approach combining PFVO with a trochanteric flip osteotomy.
View Article and Find Full Text PDFGadopiclenol Enables Reduced Gadolinium Dose While Maintaining Quality of Pulmonary Arterial Enhancement for Pulmonary MRA: An Opportunity for Improved Safety and Sustainability.
Invest Radiol
January 2025
From the Departments of Radiology (J.F.H., S.Y.C., J.-P.G., J.S., P.N., S.B.R., T.M.G.), Biomedical Engineering (S.B.R., T.M.G.), Medical Physics (S.Y.C., S.B.R., T.M.G.), Medicine (S.B.R.), and Emergency Medicine (S.B.R.), University of Wisconsin-Madison, WI; and Department of Diagnostic and Interventional Radiology (J.F.H., J.-P.G.), University Hospital Würzburg, Würzburg, Germany.
Rationale And Objectives: Pulmonary magnetic resonance angiography (MRA) is an imaging method with proven utility for the exclusion of pulmonary embolism and avoids the need for ionizing radiation and iodinated contrast agents. High-relaxivity gadolinium-based contrast agents (GBCAs), such as gadopiclenol, can be used to reduce the required gadolinium dose for pulmonary MRA. The aim of this study was to compare the contrast enhancement performance of gadopiclenol with an established gadobenate dimeglumine-enhanced pulmonary MRA protocol.
View Article and Find Full Text PDFIn vivo simultaneous proton resonance frequency shift thermometry and single reference variable flip angle T measurements.
Magn Reson Med
January 2025
Department of Radiology and Imaging Sciences, University of Utah Health, Salt Lake City, Utah, USA.
Purpose: The single reference variable flip angle sequence with a multi-echo stack of stars acquisition (SR-VFA-SoS) simultaneously measures temperature change using proton resonance frequency (PRF) shift and T-based thermometry methods. This work evaluates SR-VFA-SoS thermometry in MR-guided focused ultrasound in an in vivo rabbit model.
Methods: Simultaneous PRF shift thermometry and T-based thermometry were obtained in a New Zealand white rabbit model (n = 7) during MR-guided focused ultrasound surgery using the SR-VFA-SoS sequence at 3 T.
Determining the Rates of α-Tocopherol Movement in DPPC Vesicles Using Small Angle Neutron Scattering.
Biophys J
January 2025
Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada. Electronic address:
α-Tocopherol (αtoc, vitamin E) is an essential nutrient sufficiently acquired through a balanced diet. This fat-soluble vitamin is most known for its antioxidative properties, however, its fundamental mechanism of action in cellular membranes remains unknown. To this end, we use time-resolved small angle neutron scattering (TR-SANS) and a contrast matching scheme to determine intervesicular exchange (k) and intrabilayer flip-flop (k) rates of αtoc in 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) vesicles.
View Article and Find Full Text PDFThree-dimensional high-isotropic-resolution MR fingerprinting optimized for 0.55 T.
Magn Reson Med
January 2025
Department of Radiology, Stanford University, Stanford, California, USA.
Purpose: To provide a fast quantitative imaging approach for a 0.55T scanner, where signal-to-noise ratio is limited by the field strength and k-space sampling speed is limited by a lower specification gradient system.
Methods: We adapted the three-dimensional spiral projection imaging MR fingerprinting approach to 0.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!