GABA, glutamate and excitatory-inhibitory ratios measured using short-TE STEAM MRS at 7-Tesla: Effects of macromolecule basis sets and baseline parameters.

Rationale And Objectives: Macromolecules (MMs) affect the precision and accuracy of neurochemical quantification in magnetic resonance spectroscopy. A measured MM basis is increasingly used in LCModel analysis combined with a spline baseline, whose stiffness is controlled by a parameter named DKNTMN. The effects of measured MM basis and DKNTMN were investigated.

Quantification of Cerebral Glucose Concentrations via Detection of the H1-α-Glucose Peak in H MRS at 7 T.

Background: Sensitive detection and quantification of cerebral glucose is desired.

Purpose: To quantify cerebral glucose by detecting the H1-α-glucose peak at 5.23 ppm in H magnetic resonance spectroscopy at 7 T.

Simultaneous multislice diffusion-weighted imaging versus standard diffusion-weighted imaging in whole-body PET/MRI.

Objective: To compare standard (STD-DWI) single-shot echo-planar imaging DWI and simultaneous multislice (SMS) DWI during whole-body positron emission tomography (PET)/MRI regarding acquisition time, image quality, and lesion detection.

Methods: Eighty-three adults (47 females, 57%), median age of 64 years (IQR 52-71), were prospectively enrolled from August 2018 to March 2020. Inclusion criteria were (a) abdominal or pelvic tumors and (b) PET/MRI referral from a clinician.

Repeatability of proton magnetic resonance spectroscopy of the brain at 7 T: effect of scan time on semi-localized by adiabatic selective refocusing and short-echo time stimulated echo acquisition mode scans and their comparison.

Background: Proton magnetic resonance spectroscopy (MRS) provides a unique opportunity for measurements of the brain's metabolic profile. Two methods of mainstream data acquisition are compared at 7 T, which provides certain advantages as well as challenges. The two representative methods have seldom been compared in terms of measured metabolite concentrations and different scan times.

Comparison of Functional Free-Breathing Pulmonary H and Hyperpolarized Xe Magnetic Resonance Imaging in Pediatric Cystic Fibrosis.

Rationale And Objectives: Phase resolved functional lung (PREFUL) magnetic resonance imaging (MRI) is a free-breathing H-based technique that produces maps of fractional ventilation (FV). This study compared ventilation defect percent (VDP) calculated using PREFUL to hyperpolarized (HP) Xe MRI and pulmonary function tests in pediatric cystic fibrosis (CF).

Materials And Methods: 27 pediatric participants were recruited (mean age 13.

Image quality and diagnostic accuracy of complex-averaged high b value images in diffusion-weighted MRI of prostate cancer.

Purpose: To evaluate the impact of complex-averaging on image quality (IQ) and diagnostic accuracy of acquired and calculated high b value (aHBV, cHBV) images in diffusion-weighted prostate MRI.

Materials And Methods: This retrospective study included 84 patients who underwent multiparametric prostate MRI at 3 Tesla without endorectal coil. DWIs were acquired at three different b values which included two lower b values (b = 50,900 s/mm) and one higher b value (aHBV at 2000 s/mm).

Language universals engage Broca's area.

It is well known that natural languages share certain aspects of their design. For example, across languages, syllables like blif are preferred to lbif. But whether language universals are myths or mentally active constraints-linguistic or otherwise-remains controversial.

Validation of catheter segmentation for MR-guided gynecologic cancer brachytherapy.

Segmentation of interstitial catheters from MRI needs to be addressed in order for MRI-based brachytherapy treatment planning to become part of the clinical practice of gynecologic cancer radiotherapy. This paper presents a validation study of a novel image-processing method for catheter segmentation. The method extends the distal catheter tip, interactively provided by the physician, to its proximal end, using knowledge of catheter geometry and appearance in MRI sequences.

Analysis of myocardial perfusion MRI.

Rapid MR imaging (MRI) during the first pass of an injected tracer is used to assess myocardial perfusion with a spatial resolution of 2-3 mm, and to detect any regional impairments of myocardial blood flow (MBF) that may lead to ischemia. The spatial resolution is sufficient to detect flow reductions that are limited to the subendocardial layer. The capacity of the coronary system to increase MBF severalfold in response to vasodilation can be quantified by analysis of the myocardial contrast enhancement.

Applications of magnetic resonance imaging for cardiac stem cell therapy.

Background: The latest generation of interactive cardiac magnetic resonance (MR) scanners has made cardiac interventions with real-time MRI possible. To date, cardiac MRI has been mostly applied to measure myocardial perfusion, viability, and regional function, but now the application of cardiac MRI can be extended to cardiovascular interventions. The purpose of this article is to illustrate the potential of MRI in stem cell therapy for cardiac restoration.

An approach to the three-dimensional display of left ventricular function and viability using MRI.

Cardiac MRI was performed in human volunteers to determine the magnitude of the misregistration (MSR) of cardiac landmarks due to variability in the diaphragm position for repeated breath-holds. Seven normal volunteers underwent MR imaging of the left ventricle (LV) to evaluate the magnitude of the endocardial centroid MSR. The MSR for a mid-ventricle short-axis image was 3.

Magnetic resonance imaging guided cardiovascular interventions in congenital heart diseases.

The purpose of this article is to present some recent applications of diagnostic and interventional MRI in congenital heart disease. To date x-ray-based techniques have been the norm for most diagnostic and therapeutic applications. With the advent of ultrafast MRI and the development of MRI-compatible catheters and guide wires, the goal of achieving real-time guidance by MRI for interventions in congenital heart diseases has proven feasible.

Feedback-assisted three-dimensional reconstruction of the left ventricle with MRI.

Purpose: To develop and test a new technique for rapid, accurate three-dimensional (3D) reconstruction of the left ventricle (LV) and calculation of its volume parameters, with images from multiple orientations and interactive feedback.

Materials And Methods: The ventricular surface was fit to a number of user-placed guide points in magnetic resonance (MR) images using bivariate smoothing splines. A 3D model was reconstructed and the LV volumes were calculated at both end diastole (ED) and end systole (ES).

Magnetic resonance image-guided transcatheter closure of atrial septal defects.

Background: Recent developments in cardiac MRI have extended the potential spectrum of diagnostic and interventional applications. The purpose of this study was to test the ability of MRI to perform transcatheter closures of secundum type atrial septal defects (ASD) and to assess ASD size and changes in right cardiac chamber volumes in the same investigation.

Methods And Results: In 7 domestic swine (body weight, 38+/-13 kg), an ASD (Q(p):Q(s)=1.

Myocardial blood flow quantification with MRI by model-independent deconvolution.

Magnetic resonance (MR) imaging during the first pass of an injected contrast agent has been used to assess myocardial perfusion, but the quantification of blood flow has been generally judged as too complex for its clinical application. This study demonstrates the feasibility of applying model-independent deconvolution to the measured tissue residue curves to quantify myocardial perfusion. Model-independent approaches only require minimal user interaction or expertise in modeling.