Rapid and motion-robust pediatric brain imaging: T2-weighted turbo-spin-echo PROPELLER acquisition with compressed sensing.

Background: In pediatric magnetic resonance imaging (MRI), reducing the rate of non-diagnostic scans due to artifacts and shortening acquisition time are crucial not only for economic reasons but also to minimize sedation or general anesthesia.

Objective: Enabling faster and motion-robust MRI of the brain in infants and children using a novel, enhanced compressed sensing (CS) algorithm in combination with a turbo-spin-echo T2-weighted sequence utilizing the PROPELLER-technique (periodically rotated overlapping parallel lines with enhanced reconstruction; T2).

Materials And Methods: This prospective study included 31 patients (8.

Assessing diastolic function using CMR as an alternative to echocardiography: age- and gender-related normal reference values.

Background: Impaired diastolic function is associated with a variety of diseases such as myocarditis or dilated cardiomyopathy. Currently, echocardiography is the standard method for assessing diastolic function. Recently, it has been postulated that cardiovascular magnetic resonance (CMR) is an at least equivalent or superior alternative to echocardiography.

Assessment of CMR Feature-Tracking Age- and Sex-Dependent Right Ventricular Strain in a Healthy Caucasian Cohort.

Right ventricular (RV) strain offers crucial diagnostic insights in cardiovascular and pulmonary disorders. Nonetheless, the absence of established reference values impedes its clinical implementation. Utilizing CMR-feature tracking, age- and gender-dependent RV strains were systematically assessed in 175 heart-healthy Caucasians, 97 females, median 32.

Three-dimensional assessment of image distortion induced by active cardiac implants in 3.0T CMR.

CMR at 3.0T in the presence of active cardiac implants remains a challenge due to susceptibility artifacts. Beyond a signal void that cancels image information, magnetic field inhomogeneities may cause distorted appearances of anatomical structures.

Deep Learning Super-Resolution Reconstruction for Fast and Motion-Robust T2-weighted Prostate MRI.

Background Deep learning (DL) reconstructions can enhance image quality while decreasing MRI acquisition time. However, DL reconstruction methods combined with compressed sensing for prostate MRI have not been well studied. Purpose To use an industry-developed DL algorithm to reconstruct low-resolution T2-weighted turbo spin-echo (TSE) prostate MRI scans and compare these with standard sequences.

Assessment of pulmonary artery stiffness by multiparametric cardiac magnetic resonance-surrogate for right heart catheterization.

Background: Cardiac magnetic resonance (CMR) imaging allows for multiparametric assessment of healthy pulmonary artery (PA) hemodynamics. Gender- and aging-associated PA stiffness and pressure alterations have remained clinically unestablished, however may demonstrate epidemiological differences in disease development. The aim of this study is to evaluate the role of CMR as a surrogate for catheter examinations by providing a comprehensive CMR assessment of sex- and age-related reference values for PA stiffness, flow, and pressure.

Signal voids of active cardiac implants at 3.0 T CMR.

Recent technical advancements allow cardiac MRI (CMR) examinations in the presence of so-called MRI conditional active cardiac implants at 3.0 T. However, the artifact burden caused by susceptibility effects remain an obstacle.

Assessment of coronary artery disease by post-mortem cardiac MR.

Objectives: Minimally invasive or virtual autopsies are being advocated as alternative to traditional autopsy, but have limited abilities to detect coronary artery disease. It was the objective of this study to assess if the occurrence of chemical shift artifacts (CSA) along the coronary arteries on non-contrast, post-mortem cardiac MR may be used to investigate coronary artery disease.

Methods: We retrospectively compared autopsy and CT findings of 30 cases with significant (≥75%), insignificant (<75%), or absent coronary artery stenosis to post-mortem cardiac MR findings.

The influence of body temperature on image contrast in post mortem MRI.

Objective: To assess the temperature dependency of tissue contrast on post mortem magnetic resonance (PMMR) images both objectively and subjectively; and to visually demonstrate the changes of image contrast at various temperatures.

Materials And Methods: The study was approved by the responsible justice department and the ethics committee. The contrast of water, fat, and muscle was measured using regions of interest (ROI) in the orbit of 41 human corpses to assess how body temperature (range 2.

Assessment of magnetization transfer effects in myocardial tissue using balanced steady-state free precession (bSSFP) cine MRI.

Magnetization transfer imaging (MTI) by means of MRI exploits the mobility of water molecules in tissue and offers an alternative contrast mechanism beyond the more commonly used mechanisms based on relaxation times. A cardiac MTI method was implemented on a commercially available 1.5 T MR imager.

Disparity between ratios of diameters and blood flows in central pulmonary arteries in postoperative congenital heart disease using MRI.

Purpose: To compare the relative severity of stenoses of right or left pulmonary arteries with differences in flow to each lung after repair of congenital heart disease (CHD).

Materials And Methods: A total of 15 patients with postoperative congenital heart disease underwent MRI to evaluate branch pulmonary artery stenoses. Spin-echo images and MR angiography were used to assess morphology, and velocity-encoded cine (VEC) MRI was used to measure flow in the right and left pulmonary arteries.

MR evaluation of cardiovascular physiology in congenital heart disease: flow and function.

Cardiovascular magnetic resonance (CMR) has become the method of choice in the evaluation of a number of questions in congenital heart disease. In addition to morphology, modern CMR techniques allow the visualization of function and flow in a temporally resolved manner. Among the pathologies where these methods play a major role are shunts, septal defects, aortic coarctation, anomalies of the pulmonary arteries, and valvular regurgitation.

Placement of deep brain stimulator electrodes using real-time high-field interventional magnetic resonance imaging.

A methodology is presented for placing deep brain stimulator electrodes under direct MR image guidance. The technique utilized a small, skull-mounted trajectory guide that is optimized for accurate alignment under MR fluoroscopy. Iterative confirmation scans are used to monitor device alignment and brain penetration.

Carotid stent delivery in an XMR suite: immediate assessment of the physiologic impact of extracranial revascularization.

Background And Purpose: Patients undergoing stent placement as treatment for severe stenosis of the internal carotid artery (ICA) were assessed with MR imaging in a combined MR-radiographic (XMR) angiography suite. MR imaging was performed before and immediately following conventional radiography-guided stent placement. Changes in MR imaging measurable properties, including flow and perfusion, resulting from stent placement were evaluated.

Free-breathing, three-dimensional coronary artery magnetic resonance angiography: comparison of sequences.

Purpose: To compare six free-breathing, three-dimensional, magnetization-prepared coronary magnetic resonance angiography (MRA) sequences.

Materials And Methods: Six bright-blood sequences were evaluated: Cartesian segmented gradient echo (C-SGE), radial SGE (R-SGE), spiral SGE (S-SGE), spiral gradient echo (S-GE), Cartesian steady-state free precession (C-SSFP), and radial SSFP (R-SSFP). The right coronary artery (RCA) was imaged in 10 healthy volunteers using all six sequences in randomized order.

Whole-heart steady-state free precession coronary artery magnetic resonance angiography.

Current implementations of coronary artery magnetic resonance angiography (MRA) suffer from limited coverage of the coronary arterial system. Whole-heart coronary MRA was implemented based on a free-breathing steady-state free-precession (SSFP) technique with magnetization preparation. The technique was compared to a similar implementation of conventional, thin-slab coronary MRA in 12 normal volunteers.

Experimental renal artery embolization in a combined MR imaging/angiographic unit.

Purpose: The purpose of this study was to use a combined x-ray angiography and MR imaging (XMR) system to manipulate intraarterial catheters and monitor the deposition of gadolinium (Gd)-impregnated embolic microspheres in vivo in a canine kidney model.

Materials And Methods: Seven anesthetized dogs (18-28 kg) were studied. The renal arteries were catheterized under fluoroscopic guidance.

Steady-state imaging for visualization of endovascular interventions.

Steady-state imaging techniques offer the potential to couple high spatial and temporal resolution with good signal-to-noise ratio (SNR), which makes them ideally suited for fluoroscopic applications. However, disturbance of the steady state can result in artifacts and substantially reduced signal levels. In this study the use of steady-state imaging techniques was investigated as a means of guiding endovascular interventions with fluoroscopic MRI.

Endovascular stents in pulmonary valve and artery in swine: feasibility study of MR imaging-guided deployment and postinterventional assessment.

Purpose: To assess the feasibility of using magnetic resonance (MR) imaging to guide stent deployment in the pulmonary valve and artery and evaluate, after stent deployment, the position and morphology of and blood flow through the stent.

Materials And Methods: Angiography and 1.5-T MR imaging were performed in a dual-imaging suite.

MR portal venography: preliminary results of fast acquisition without contrast material or breath holding.

Rationale And Objectives: The authors performed this study to evaluate the feasibility of using the steady-state free precession (SSFP) sequence to perform magnetic resonance (MR) venography of the portal venous system without the use of contrast material or breath holding.

Materials And Methods: Eleven patients underwent MR venography with the SSFP technique. Coronal three-dimensional images were obtained with respiratory triggering.

Real-time MR properties of particulate embolic agents tested in a dynamic flow model.

Purpose: Interventional magnetic resonance (MR)-guided transcatheter embolization could potentially limit radiation exposure and improve visualization of target organs. The feasibility of monitoring injection and distribution of embolic agents was assessed in a dynamic flow model with real-time MR imaging.

Materials And Methods: MR-compatible flow models were constructed with use of clear plastic chambers containing 170-microm polyethylene tubular filters.

Single breath-hold extended free-breathing navigator-gated three-dimensional coronary MRA.

Purpose: To acquire the center of k-space while extending three-dimensional free-breathing navigator-gated coronary magnetic resonance (MR) angiography by an initial single breath-hold.

Materials And Methods: This approach was successfully applied in eight healthy adult subjects. Resulting images were compared with conventionally acquired free-breathing navigator-gated MR angiograms.