"MRI pulse sequence" from_date:2012

The Optimization of Magnetic Resonance Imaging Pulse Sequences in Order to Better Detection of Multiple Sclerosis Plaques Magnetic resonance imaging (MRI) is the most sensitive technique to detect multiple sclerosis (MS) plaques in central nervous system. In some cases, the patients who were suspected to MS, Whereas MRI images are normal, but whether patients don't have MS plaques or MRI images

Generalized min-max bound-based MRI pulse sequence design framework for wide-range T1 relaxometry: A case study on the tissue specific imaging sequence. This paper proposes a new design strategy for optimizing MRI pulse sequences for T1 relaxometry. The design strategy optimizes the pulse sequence parameters to minimize the maximum variance of unbiased T1 estimates over a range of T1 values using

Dual-echo and Inversion Recovery Magnetic Resonance Imaging Pulse Sequences in Diagnosis of Temporomandibular Disorders. Diagnostic Accuracy Study In the present study, investigators are going to investigate the potential of inversion recovery (fluid attenuated inversion recovery -FLAIR and short-TI Inversion Recovery -STIR) sequence images to demonstrate joint effusion, compared to T2-weighted

ZTE MRI Pulse Sequence Use for Visualization of Bone Cement, Breast Biopsy Markers This study is being done to determine if a clinically available MRI sequence called ZTE imaging better visualizes breast biopsy markers made of bone cement compared to the currently used breast biopsy markers made of metal. PRIMARY OBJECTIVE: I. To demonstrate that clinically available ZTE imaging allows for better

different. Since ADC values can differ between different scanners and DW MRI pulse sequences, an ADC threshold may be difficult to generalize across institutes, in our data set a threshold of 900 mm/s was useful in separating the two diagnoses with a high degree of accuracy. Clinical features of retinoblastoma and Coats' disease often resemble each other and can lead to misdiagnosis. Since ADCs

understanding and knowledge of the patient’s clinical history, as well as the anatomy and pathophysiology relevant to the MRI examination [6]. The supervising physician must be familiar with the wide spectrum of MRI pulse sequences that can be used in head and neck imaging and their effects on the appearance of the images, including image artifacts. Standard imaging protocols should

1 year. Secondarily we evaluated two diffusion magnetic resonance imaging pulse sequences to determine the best sequence to measure disease progression. This prospective, randomized, double-blind, placebo-controlled trial assessed the effects of rasagiline administered at 1 mg/day over 12 months in early-stage PD. The primary outcome was 1-year change in free-water accumulation in posterior substantia nigra (pSN) measured using two diffusion magnetic resonance imaging pulse sequences, one with a repetition time (TR) of 2500 ms (short TR; n = 90) and one with a TR of 6400 ms (long TR; n = 75). Secondary clinical outcomes also were assessed. Absolute change in pSN free-water accumulation was not significantly different between groups (short TR: P = 0.346; long TR: P = 0.228). No significant

DNA either in the CSF or by histopathology, is an important tool in the detection of PML. In clinical practice, standard MRI pulse sequences are utilized for screening, diagnosis and monitoring of PML, but validated imaging-based outcome measures for use in prospective, interventional clinical trials for PML have yet to be established. We review the existing literature regarding the use of MRI

Qualitative and Quantitative Analysis of a Spiral Gradient Echo Sequence for Contrast-Enhanced Fat-Suppressed T1-Weighted Spine Magnetic Resonance Imaging. Pulse sequences with non-Cartesian k-space sampling enable improved imaging in anatomical areas with high degrees of motion artifacts. We analyzed a novel spiral 3-dimensional (3D) gradient echo (GRE) magnetic resonance imaging (MRI) sequence

]. Fortunately, nonenhanced MRI pulse sequences may provide useful information in patients that have contrast contraindications and serve as an alternative to CT. Although digital subtraction angiography remains the reference standard for the anatomic delineation of the renal arteries, MRA permits a noninvasive method to evaluate for RAS and does not expose the patient to ionizing

in clinically relevant perpendicular, 45-degree oblique, and parallel orientations relative to the static magnetic field (B0) and center, right off-center, and left off-center needle tip locations in the z = 0 plane. Clinically available interventional MRI pulse sequences including turbo spin echo (TSE), fast TSE, slice encoding for metal artifact correction, compressed sensing slice encoding for metal

individual with an implanted cardiac device who was referred for MRI was included. Clinical MRI protocols without SAR restriction were used. Exclusion criteria were newly implanted leads, abandoned or epicardial leads, and dependence on a pacemaker with an implantable cardioverter defibrillator without asynchronous pacing capability. For each MRI pulse sequence, the calculated whole-body values for SAR, dB

repair) were enrolled. Patients with a history of previous injury or surgery to either knee were excluded. Patients returned for UTE MRI at 1, 3, 6, 9, and 12 months after ACL reconstruction. Imaging at 1 month included the contralateral knee. MRI pulse sequences included high-resolution 3-dimensional gradient echo sequence and a 4-echo T2-UTE sequence (slice thickness, 1 mm; repetition time, 20 ms

. A super-resolution approach was developed to combine fast 3-dimensional (3D) cine MRI with low resolution during free breathing (FB) and high-resolution 3D static MRI during breath hold (BH) using deformable image registration. A T1-weighted, turbo field echo sequence, coronal 3D cine acquisition, partial Fourier approximation, and SENSitivity Encoding parallel acceleration were used. The same MRI pulse sequence, field of view, and acceleration techniques were applied in both FB and BH acquisitions; the intensity-based Demons deformable image registration method was used. Under an institutional review board-approved protocol, 7 volunteers were studied with 3D cine FB scan (voxel size: 5 × 5 × 5 mm) at 2 Hz for 40 seconds and a 3D static BH scan (2 × 2 × 2 mm). To examine the image fidelity of 3D cine

Comparison of MRI sequences in ideal fiducial maker-based radiotherapy for prostate cancer Prostate contouring using CT alone is difficult. To overcome the uncertainty, CT/MRI registration using a fiducial marker is generally performed. However, visualization of the marker itself can be difficult with MRI. This study aimed to determine the optimal MRI pulse sequence for defining the marker

Renal volumetry with magnetic resonance imaging No gold standard exists for renal volumetry in vivo. To devise and evaluate segmentation methods on magnetic resonance imaging (MRI) datasets. Five combinations of MRI pulse sequences and measuring methods were used to measure the renal volumes of five men aged 54-72 years scanned before autologous renal stem cell transplantation and three, six

MB-SWIFT functional MRI during deep brain stimulation in rats Recently introduced 3D radial MRI pulse sequence entitled Multi-Band SWeep Imaging with Fourier Transformation (MB-SWIFT) having virtually zero acquisition delay was used to obtain functional MRI (fMRI) contrast in rat's brain at 9.4 T during deep brain stimulation (DBS). The results demonstrate that MB-SWIFT allows functional images

Liquid crystal phantom for validation of microscopic diffusion anisotropy measurements on clinical MRI systems To develop a phantom for validating MRI pulse sequences and data processing methods to quantify microscopic diffusion anisotropy in the human brain. Using a liquid crystal consisting of water, detergent, and hydrocarbon, we designed a 0.5-L spherical phantom showing the theoretically

Positive Contrast from Cells Labeled with Iron Oxide Nanoparticles. Quantitation of Imaging Data Conventional T -weighted MRI produces a hypointense signal from iron-labeled cells, which renders quantification unfeasible. We tested a SWeep Imaging with Fourier Transformation (SWIFT) MRI pulse sequence to generate a quantifiable hyperintense signal from iron-labeled cells. Mesenchymal stem cells

a clear understanding and knowledge of the patient’s clinical history, as well as the anatomy and pathophysiology relevant to the MRI examination [5]. The supervising physician must be familiar with the wide spectrum of MRI pulse sequences that can be used in head and neck imaging, and their effects on the appearance of the images, including image artifacts. Standard