Rejection evaluation after renal transplantation using MR diffusion tensor imaging.

Background Renal allograft dysfunction monitoring is mainly performed using the serum creatinine (SC) level, Doppler ultrasound (US), or renal biopsy. Recently proposed diffusion-based magnetic resonance imaging (MRI) methods have been explored as new, non-invasive tools for assessing renal function after transplantation. Purpose To investigate the value of fractional anisotropy (FA) measurements in the evaluation of acute rejection cases after renal transplant.

Characterization of 3D geometric distortion of magnetic resonance imaging scanners commissioned for radiation therapy planning.

Objective: To develop a method for the assessment and characterization of 3D geometric distortion as part of routine quality assurance for MRI scanners commissioned for Radiation Therapy planning.

Materials And Methods: In this study, the in-plane and through-plane geometric distortions on a 1.5T GE MRI-SIM unit are characterized and the 2D and 3D correction algorithms provided by the vendor are evaluated.

Effect of imaging parameters on the accuracy of apparent diffusion coefficient and optimization strategies.

Purpose: We aimed to investigate the effect of key imaging parameters on the accuracy of apparent diffusion coefficient (ADC) maps using a phantom model combined with ADC calculation simulation and propose strategies to improve the accuracy of ADC quantification.

Methods: Diffusion-weighted imaging (DWI) sequences were acquired on a phantom model using single-shot echo-planar imaging DWI at 1.5 T scanner by varying key imaging parameters including number of averages (NEX), repetition time (TR), echo time (TE), and diffusion preparation pulses.

A comparison of liver fat content as determined by magnetic resonance imaging-proton density fat fraction and MRS versus liver histology in non-alcoholic fatty liver disease.

Background: Many imaging methods have been defined for quantification of hepatic steatosis in non-alcoholic fatty liver disease (NAFLD). However, studies comparing the efficiency of magnetic resonance imaging-proton density fat fraction (MRI-PDFF), magnetic resonance spectroscopy (MRS), and liver histology for quantification of liver fat content are limited.

Purpose: To compare the efficiency of MRI-PDFF and MRS in the quantification of liver fat content in individuals with NAFLD.

Quantification of liver, pancreas, kidney, and vertebral body MRI-PDFF in non-alcoholic fatty liver disease.

Purpose: The purpose of the present study was to determine liver, pancreas, kidney, and vertebral fat deposition in NAFLD patients by proton density fat fraction (PDFF) using magnetic resonance imaging (MRI) and to evaluate the relationships among them.

Methods: A total of 41 biopsy-proven NAFLD patients underwent MRI-PDFF with IDEAL-IQ. MRI protocol included T1-independent volumetric multi-echo gradient-echo imaging with T2* correction and spectral fat modeling.

Fat fraction estimation of the vertebrae in females using the T2*-IDEAL technique in detection of reduced bone mineralization level: comparison with bone mineral densitometry.

Objective: The aim of this study was to use the T2*-iterative decomposition of water and fat with echo asymmetry and least squares estimation quantification (IDEAL) technique to estimate vertebral fat fraction (FF) and compare it with bone mineralization levels in females.

Materials And Methods: Forty-five (mean age, 49.5 years) consecutive women who underwent magnetic resonance imaging and spinal dual-energy x-ray absorptiometry bone mineral density (BMD) examination constituted the study population.

Is quantitative magnetic resonance imaging valuable in the assessment of trabecular bone structure in osteoporosis?

Objectives: This study aims to evaluate the value of quantitative magnetic resonance imaging in the assessment of bone trabeculae in osteoporosis by comparing the results with dual-energy X-ray (DXA) absorptiometry.

Patients And Methods: The study consisted of 85 postmenopausal women (mean age 57.2 years; range 43 to 83 years) underwent both DXA absorptiometry and lumbar quantitative magnetic resonance imaging.

Hepatic steatosis: quantification by proton density fat fraction with MR imaging versus liver biopsy.

Purpose: To determine utility of proton density fat fraction (PDFF) measurements for quantifying the liver fat content in patients with nonalcoholic fatty liver disease (NAFLD), and compare these results with liver biopsy findings.

Materials And Methods: This retrospective study was approved by the institutional review board with waivers of informed consent. Between June 2010 and April 2011, 86 patients received a diagnosis of NAFLD.

Staging of hip avascular necrosis: is there a need for DWI?

Background: No comprehensive study has been performed to stage avascular necrosis of the hip using diffusion-weighted imaging (DWI).

Purpose: To determine apparent diffusion co-efficient (ADC) alterations in hip avascular necrosis (AVN) and to determine variations of ADC values according to stages of disease.

Material And Methods: The study is approved by our institutional review board and local ethical committee.

The role of DTI in early detection of cervical spondylotic myelopathy: a preliminary study with 3-T MRI.

Introduction: The radiological diagnosis of cervical spondylotic myelopathy (CSM) has to be made as soon as possible, since surgery performed in earlier stages during the course of CSM was reported to be more successful when compared with later stages. We hypothesized that diffusion tensor imaging (DTI) may detect CSM in earlier stages, before the appearance of signal increase in T2-weighted sequences.

Methods: A total of 16 patients with neurological signs and symptoms of CSM but without hyperintensity in spinal cord on T2-weighted sequences enrolled in the study.

Focal sparing of iron and fat in liver tissue in patients with hemosiderosis: diagnosis with combination of R2* relaxometry and proton density fat fraction calculation by MRI.

Purpose: To demonstrate magnetic resonance imaging (MRI) findings of the focal sparing of iron and fat in liver tissue in patients with hepatic iron overload.

Materials And Methods: We retrospectively reviewed 48 liver MRIs performed in patients with hemosiderosis from 2007-2009. We selected five (10%) of these patients based on the observation of focal signal abnormalities in the posterior aspect of segment 4, anterior to the portal vein, on in- and out-of-phase T1-weighted gradient-echo images.

Diffusion-weighted imaging of the appendicular skeleton with a non-Carr-Purcell-Meiboom-Gill single-shot fast spin-echo sequence.

Objective: The objective of our study was to prospectively evaluate the signal-to-noise ratio (SNR) improvement in diffusion-weighted imaging (DWI) of the appendicular skeleton with the use of a newly developed non-Carr-Purcell-Meiboom-Gill (non-CPMG) single-shot fast spin-echo (SSFSE) sequence and to evaluate its effect on apparent diffusion coefficient (ADC) measurements.

Subjects And Methods: DWI of the bone was performed in 32 patients with an echo-planar imaging (EPI)-based sequence followed by a non-CPMG SSFSE technique. SNR and ADC values were measured over a lesion-free right femoral head.

Magnetic resonance cerebral metabolic rate of oxygen utilization in hyperacute stroke patients.

The purpose of this study was to explore the feasibility of obtaining magnetic resonance-measured cerebral metabolic rate of oxygen utilization (MR-CMRO(2)) in acute ischemic stroke patients. Seven stroke patients were serially imaged: 4.5 +/- 0.