Safety and technique of ferumoxytol administration for MRI.

Ferumoxytol is an ultrasmall superparamagnetic iron oxide agent marketed for the treatment of anemia. There has been increasing interest in its properties as an MRI contrast agent as well as greater awareness of its adverse event profile. This mini-review summarizes the current state of knowledge of the risks of ferumoxytol and methods of administration.

Contrast enhanced pulmonary magnetic resonance angiography for pulmonary embolism: Building a successful program.

The performance of contrast enhanced pulmonary magnetic resonance angiography (MRA) for the diagnosis of pulmonary embolism (PE) is an effective non-ionizing alternative to contrast enhanced computed tomography and nuclear medicine ventilation/perfusion scanning. However, the technical success of these exams is very dependent on careful attention to the details of the MRA acquisition protocol and requires reader familiarity with MRI and its artifacts. Most practicing radiologists are very comfortable with the performance and interpretation of computed tomographic angiography (CTA) performed to detect pulmonary embolism but not all are as comfortable with the use of MRA in this setting.

Quantitative Imaging Biomarkers of NAFLD.

Conventional imaging modalities, including ultrasonography (US), computed tomography (CT), and magnetic resonance (MR), play an important role in the diagnosis and management of patients with nonalcoholic fatty liver disease (NAFLD) by allowing noninvasive diagnosis of hepatic steatosis. However, conventional imaging modalities are limited as biomarkers of NAFLD for various reasons. Multi-parametric quantitative MRI techniques overcome many of the shortcomings of conventional imaging and allow comprehensive and objective evaluation of NAFLD.

Systematic review and meta-analysis of the accuracy of MRI to diagnose appendicitis in the general population.

Purpose: To perform a systematic review and meta-analysis of all published studies since 2005 that evaluate the accuracy of magnetic resonance imaging (MRI) for the diagnosis of acute appendicitis in the general population presenting to emergency departments.

Materials And Methods: All retrospective and prospective studies evaluating the accuracy of MRI to diagnose appendicitis published in English and listed in PubMed, Web of Science, Cinahl Plus, and the Cochrane Library since 2005 were included. Excluded studies were those without an explicitly stated reference standard, with insufficient data to calculate the study outcomes, or if the population enrolled was limited to pregnant women or children.

Longitudinal Changes in Liver Fat Content in Asymptomatic Adults: Hepatic Attenuation on Unenhanced CT as an Imaging Biomarker for Steatosis.

Objective: The objective of this study was to evaluate changes in liver fat content over time in asymptomatic adults and to investigate the factors that may influence these changes.

Materials And Methods: Liver attenuation on unenhanced CT images of 1022 asymptomatic adults (556 women and 466 men; mean age at the time of the index CT examination, 56.7 years) was retrospectively measured on initial and surveillance CT colonography screening examinations (mean [± SD] interval, 5.

An Investigation of Transient Severe Motion Related to Gadoxetic Acid-enhanced MR Imaging.

Purpose: To investigate the cause of imaging artifacts observed during gadoxetic acid-enhanced arterial phase imaging of the liver.

Materials And Methods: This HIPAA-compliant study was approved by the institutional review board. Data were collected prospectively at two sites (site A, United States; site B, Japan) from patients undergoing contrast material-enhanced MR imaging with gadoxetic acid (site A, n = 154, dose = 0.

The White-Nose Syndrome Transcriptome: Activation of Anti-fungal Host Responses in Wing Tissue of Hibernating Little Brown Myotis.

White-nose syndrome (WNS) in North American bats is caused by an invasive cutaneous infection by the psychrophilic fungus Pseudogymnoascus destructans (Pd). We compared transcriptome-wide changes in gene expression using RNA-Seq on wing skin tissue from hibernating little brown myotis (Myotis lucifugus) with WNS to bats without Pd exposure. We found that WNS caused significant changes in gene expression in hibernating bats including pathways involved in inflammation, wound healing, and metabolism.

Pulmonary Embolism Detection with Three-dimensional Ultrashort Echo Time MR Imaging: Experimental Study in Canines.

Purpose: To demonstrate the feasibility of free-breathing three-dimensional (3D) radial ultrashort echo time (UTE) magnetic resonance (MR) imaging in the simultaneous detection of pulmonary embolism (PE) and high-quality evaluation of lung parenchyma.

Materials And Methods: The institutional animal care committee approved this study. A total of 12 beagles underwent MR imaging and computed tomography (CT) before and after induction of PE with autologous clots.

High specificity targeting and detection of human neuroblastoma using multifunctional anti-GD2 iron-oxide nanoparticles.

Aim: To develop biocompatible, tumor-specific multifunctional iron-oxide nanoconstructs targeting neuroblastoma, an aggressive pediatric malignancy.

Materials & Methods: Clinical-grade humanized monoclonal antibody (hu14.18K322A), designed to target GD2 antigen on neuroblastoma with reduced nonspecific immune interactions, was conjugated to hydroxyethyl starch-coated iron-oxide nanoparticles.

Dermal white adipose tissue: a new component of the thermogenic response.

Recent literature suggests that the layer of adipocytes embedded in the skin below the dermis is far from being an inert spacer material. Instead, this layer of dermal white adipose tissue (dWAT) is a regulated lipid layer that comprises a crucial environmental defense. Among all the classes of biological molecules, lipids have the lowest thermal conductance and highest insulation potential.

In Nonobese Girls, Waist Circumference as a Predictor of Insulin Resistance Is Comparable to MRI Fat Measures and Superior to BMI.

Objective: The aim of this study was to investigate the degree to which waist circumference (WC), body mass index (BMI), and magnetic resonance imaging (MRI)-measured abdominal fat deposition predict insulin resistance (IR) in nonobese girls of diverse racial and ethnic backgrounds.

Methods: Fifty-seven nonobese girls (12 African-American, 16 Hispanic White, and 29 non-Hispanic White girls) aged 11-14 years were assessed for WC, MRI hepatic proton density fat fraction, visceral and subcutaneous adipose tissue volume, BMI Z-score, fasting insulin, homeostasis model of assessment (HOMA)-IR, adiponectin, leptin, sex hormone-binding globulin, high-density lipoprotein cholesterol, and triglycerides.

Results: Univariate and multivariate analyses adjusted for race and ethnicity indicated that only WC and visceral adipose tissue volume were independent predictors of fasting insulin and HOMA-IR, while hepatic proton density fat fraction, BMI Z-score, and subcutaneous adipose tissue volume were dependent predictors.

Quantitative magnetic resonance imaging of hepatic steatosis: Validation in ex vivo human livers.

Unlabelled: Emerging magnetic resonance imaging (MRI) biomarkers of hepatic steatosis have demonstrated tremendous promise for accurate quantification of hepatic triglyceride concentration. These methods quantify the proton density fat-fraction (PDFF), which reflects the concentration of triglycerides in tissue. Previous in vivo studies have compared MRI-PDFF with histologic steatosis grading for assessment of hepatic steatosis.

Magnetic Resonance Angiography of the Upper Extremity.

The magnetic resonance angiography (MRA) toolbox includes a wide array of versatile methods for diagnosis and therapy planning in patients with a variety of upper extremity vascular pathologies. MRA can provide excellent image quality with high spatial and high temporal resolution without the disadvantages of ionizing radiation, iodinated contrast, and operator dependency. Contrast-enhanced techniques are preferred for their robustness, image quality, and shorter scan times.

Intraindividual Crossover Comparison of Gadoxetic Acid Dose for Liver MRI in Normal Volunteers.

Purpose: We performed a quantitative intraindividual comparison of the performance of 0.025- and 0.05-mmol/kg doses for gadoxetic acid-enhanced liver magnetic resonance (MR) imaging.

Non-contrast-enhanced MRA of renal artery stenosis: validation against DSA in a porcine model.

Objectives: To compare 3D-inversion-recovery balanced steady-state free precession (IR-bSSFP) non-contrast-enhanced magnetic resonance angiography (MRA) with 3D-contrast-enhanced MRA (CE-MRA) for assessment of renal artery stenosis (RAS) using digital subtraction angiography (DSA) as the reference standard.

Methods: Bilateral RAS were surgically created in 12 swine. IR-bSSFP and CE-MRA were acquired at 1.

Mathematical optimization of contrast concentration for T1-weighted spoiled gradient echo imaging.

Purpose: To develop and validate closed form mathematical expressions that predict the optimal contrast agent concentration for the maximum T1-weighted spoiled gradient echo (SGRE) signal.

Theory And Methods: Gadolinium and iron-based contrast agents can have significant transverse relaxivity that leads to signal dropout with increasing contrast agent concentration. A mathematical expression for the "optimal" contrast agent concentration where recovery of longitudinal magnetization is offset by increasing transverse signal decay was derived.

A data management and publication workflow for a large-scale, heterogeneous sensor network.

It is common for hydrology researchers to collect data using in situ sensors at high frequencies, for extended durations, and with spatial distributions that produce data volumes requiring infrastructure for data storage, management, and sharing. The availability and utility of these data in addressing scientific questions related to water availability, water quality, and natural disasters relies on effective cyberinfrastructure that facilitates transformation of raw sensor data into usable data products. It also depends on the ability of researchers to share and access the data in useable formats.

Proton density fat-fraction is an accurate biomarker of hepatic steatosis in adolescent girls and young women.

Objectives: To compare complex quantitative magnetic resonance imaging (MRI) with MR spectroscopy (MRS) for quantification of hepatic steatosis (HS) and determine clinically significant MRI-based thresholds of HS in female youths.

Methods: This prospective, cross-sectional study was conducted in 132 healthy females (11-22 years, mean 13.3 ± 2).

Sensitivity of chemical shift-encoded fat quantification to calibration of fat MR spectrum.

Purpose: To evaluate the impact of different fat spectral models on proton density fat fraction quantification using chemical shift-encoded MRI (CSE-MRI).

Methods: In a simulation study, spectral models of fat were compared pairwise. Comparison of magnitude fitting and mixed fitting was performed over a range of echo times and fat fractions.

Quantification of liver fat with respiratory-gated quantitative chemical shift encoded MRI.

Purpose: To evaluate free-breathing chemical shift-encoded (CSE) magnetic resonance imaging (MRI) for quantification of hepatic proton density fat-fraction (PDFF). A secondary purpose was to evaluate hepatic R2* values measured using free-breathing quantitative CSE-MRI.

Materials And Methods: Fifty patients (mean age, 56 years) were prospectively recruited and underwent the following four acquisitions to measure PDFF and R2*; 1) conventional breath-hold CSE-MRI (BH-CSE); 2) respiratory-gated CSE-MRI using respiratory bellows (BL-CSE); 3) respiratory-gated CSE-MRI using navigator echoes (NV-CSE); and 4) single voxel MR spectroscopy (MRS) as the reference standard for PDFF.

Impaired regulation of portal venous flow in response to a meal challenge as quantified by 4D flow MRI.

Purpose: Portal and mesenteric hemodynamics is greatly altered in portal hypertension patients. This study utilizes 4D flow magnetic resonance imaging (MRI) to visualize and quantify changes in abdominal hemodynamics in patients with portal hypertension undergoing meal challenge.

Materials And Methods: Twelve portal hypertension patients and six healthy subjects participated in the study.

Cytochrome P450 1B1: An unexpected modulator of liver fatty acid homeostasis.

Cytochrome P450 1b1 (Cyp1b1) expression is absent in mouse hepatocytes, but present in liver endothelia and activated stellate cells. Increased expression during adipogenesis suggests a role of Cyp1b1 metabolism in fatty acid homeostasis. Wild-type C57BL/6j (WT) and Cyp1b1-null (Cyp1b1-ko) mice were provided low or high fat diets (LFD and HFD, respectively).

Pancreatic Steatosis Demonstrated at MR Imaging in the General Population: Clinical Relevance.

Purpose: To determine the relationship between pancreatic fat content and type 2 diabetes and prediabetes.

Materials And Methods: From the prospective population-based Study of Health in Pomerania (SHIP), 1367 volunteers (563 men, 678 women; median age, 50 years) underwent whole-body magnetic resonance (MR) imaging at 1.5 T, which included multiecho chemical shift-encoded acquisition of the abdomen.