Circulating and Magnetic Resonance Imaging Biomarkers of Intestinal Fibrosis in Small Bowel Crohn's Disease.

Background: We previously identified circulating and MRI biomarkers associated with the surgical management of Crohn's disease (CD). Here we tested associations between these biomarkers and ileal resection inflammation and collagen content.

Methods: Fifty CD patients undergoing ileal resection were prospectively enrolled at 4 centers.

MRI and Blood-based Biomarkers Are Associated With Surgery in Children and Adults With Ileal Crohn's Disease.

Background: Despite advances in medical therapy, many children and adults with ileal Crohn's disease (CD) progress to fibrostenosis requiring surgery. We aimed to identify MRI and circulating biomarkers associated with the need for surgical management.

Methods: This prospective, multicenter study included pediatric and adult CD cases undergoing ileal resection and CD controls receiving medical therapy.

The influence of voxelotor on cerebral blood flow and oxygen extraction in pediatric sickle cell disease.

Voxelotor is an inhibitor of sickle hemoglobin polymerization that is used to treat sickle cell disease. Although voxelotor has been shown to improve anemia, the clinical benefit on the brain remains to be determined. This study quantified the cerebral hemodynamic effects of voxelotor in children with sickle cell anemia (SCA) using noninvasive diffuse optical spectroscopies.

Diagnostic Excellence in Pediatric Spine Imaging: Using Contextualized Imaging Protocols.

Contextual design and selection of MRI protocols is critical for making an accurate diagnosis given the wide variety of clinical indications for spine imaging in children. Here, we describe our pediatric spine imaging protocols in detail, tailored to specific clinical questions.

Study protocol for a randomized, controlled trial using a novel, family-centered diet treatment to prevent nonalcoholic fatty liver disease in Hispanic children.

Background: Non-alcoholic fatty liver disease (NAFLD) is the leading liver disorder among U.S. children and is most prevalent among Hispanic children with obesity.

Dietary sugar restriction reduces hepatic de novo lipogenesis in adolescent boys with fatty liver disease.

BACKGROUNDHepatic de novo lipogenesis (DNL) is elevated in nonalcoholic fatty liver disease (NAFLD). Improvements in hepatic fat by dietary sugar reduction may be mediated by reduced DNL, but data are limited, especially in children. We examined the effects of 8 weeks of dietary sugar restriction on hepatic DNL in adolescents with NAFLD and correlations between DNL and other metabolic outcomes.

Development of a Plasma Screening Panel for Pediatric Nonalcoholic Fatty Liver Disease Using Metabolomics.

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in children, but diagnosis is challenging due to limited availability of noninvasive biomarkers. Machine learning applied to high-resolution metabolomics and clinical phenotype data offers a novel framework for developing a NAFLD screening panel in youth. Here, untargeted metabolomics by liquid chromatography-mass spectrometry was performed on plasma samples from a combined cross-sectional sample of children and adolescents ages 2-25 years old with NAFLD (n = 222) and without NAFLD (n = 337), confirmed by liver biopsy or magnetic resonance imaging.

Effect of a Low Free Sugar Diet vs Usual Diet on Nonalcoholic Fatty Liver Disease in Adolescent Boys: A Randomized Clinical Trial.

Importance: Pediatric guidelines for the management of nonalcoholic fatty liver disease (NAFLD) recommend a healthy diet as treatment. Reduction of sugary foods and beverages is a plausible but unproven treatment.

Objective: To determine the effects of a diet low in free sugars (those sugars added to foods and beverages and occurring naturally in fruit juices) in adolescent boys with NAFLD.

Effect of repetition time on metabolite quantification in the human brain in H MR spectroscopy at 3 tesla.

Purpose: To examine the effects of repetition time (TR) on metabolite concentration measurements in the human brain in H magnetic resonance spectroscopy at 3 Tesla (T).

Materials And Methods: Spectra were acquired from the posterior cingulate of five healthy adults at repetition times of 1.5 s, 3.

Very short echo time improves the precision of glutamate detection at 3T in 1H magnetic resonance spectroscopy.

Purpose: To examine the precision of glutamate detection using a very short echo time (TE) phase rotation STEAM (PR-STEAM) sequence.

Materials And Methods: Spectrosopic data were acquired from the anterior cingulate gyrus in nine healthy adults using 6.5-msec TE PR-STEAM, 40-msec TE PRESS, 72-msec TE STEAM, and TE-Averaging with an effective TE of 105 msec on a clinical 3T magnetic resonance imaging (MRI) system.

Reconstructing very short TE phase rotation spectral data collected with multichannel phased-array coils at 3 T.

Phased-array volume coils were used in conjunction with the phase rotation STEAM (PR-STEAM) spectroscopy technique to acquire very short TE data from the anterior cingulate gyrus at 3 T. A method for combining PR-STEAM data from multiple subcoils is presented. The data were acquired from seven healthy participants using PR-STEAM (repetition time/mixing time/echo time=3500/10/6.

Increased glucose concentration in the hippocampus in early Alzheimer's disease following oral glucose ingestion.

Glucose is the primary source of energy for brain cells. Because energy storage in the brain is limited, an uninterrupted supply of glucose and its rapid metabolism are essential for normal cognitive function. This study utilized an oral glucose load to examine hippocampal glucose metabolism in early Alzheimer's disease (AD) - a disease characterized by progressive deterioration of cognitive function and glucose hypometabolism.

q-Space analysis of lung morphometry in vivo with hyperpolarized 3He spectroscopy.

Purpose: To examine the utility of a (3)He spectroscopic q-space technique for detecting changes in lung morphometry in vivo.

Materials And Methods: A diffusion-weighted spectroscopy sequence was used to collect global diffusion data from healthy adults (N = 11), healthy children (N = 5), and chronic obstructive pulmonary disease (COPD) patients (N = 2) using 40 cc of hyperpolarized (3)He gas within a two second breathhold. Displacement probability profiles (DPP) were obtained by Fourier transformation of diffusion data with respect to q.

A phase rotation scheme for achieving very short echo times with localized stimulated echo spectroscopy.

In a single-voxel stimulated echo localization sequence in magnetic resonance spectroscopy, magnetic field gradients are inserted within the echo time (TE) to filter signals generated through coherence pathways other than that leading to the stimulated echo. There is a significant penalty for these gradients as they increase the minimum TE, thereby leading to significant signal loss from spin-spin relaxation and phase distortions in coupled spin systems. Here, an RF phase rotation technique is described for a stimulated echo localization sequence that allows removal of the gradients in the TE intervals and, subsequently, reduction of the minimum TE to only 6 ms.

Increasing the speed of relaxometry-based compartmental analysis experiments in STEAM spectroscopy.

In this work we present a method for improving the speed of spin-spin relaxation time (T2) measurements for compartmental analysis in stimulated echo localized magnetic resonance spectroscopy without reducing the sampling density. The technique uses a progressive repetition time (TR) to compensate for echo time (TE) dependent variations in saturation effects that would otherwise modulate the received signal at short TRs. The method was validated in T2 studies on 10 young healthy subjects in spectroscopic voxels localized along either the right or left Sylvian fissure (2 x 2 x 1.

Shortening of hippocampal spin-spin relaxation time in probable Alzheimer's disease: a 1H magnetic resonance spectroscopy study.

We quantified the differential effects of the spin-spin relaxation times (T2) of tissue water and cerebral spinal fluid in order to examine hippocampal T2 changes as a non-invasive bio-marker of Alzheimer's disease (AD). We measured T2 in the right hippocampus of ten patients fulfilling the NINCDS-ADRDA criteria for AD and 40 healthy adult volunteers using localized proton magnetic resonance spectroscopy. The T2 values of AD patients (73 +/- 8 ms) were significantly shorter (P < 0.

Molality as a unit of measure for expressing 1H MRS brain metabolite concentrations in vivo.

Absolute concentrations of cerebral metabolite in in vivo 1H magnetic resonance spectroscopy studies (1H-MRS) are widely reported in molar units as moles per liter of tissue, or in molal units as moles per kilogram of tissue. Such measurements require external referencing or assumptions as to local water content. To reduce the scan time, avoid assumptions that may be invalid under specific pathologies, and provide a universally accessible referencing procedure, we suggest that metabolite concentrations from 1H-MRS measurements in vivo be reported in molal units as moles per kilogram of tissue water.

Imaging the lungs in asthmatic patients by using hyperpolarized helium-3 magnetic resonance: assessment of response to methacholine and exercise challenge.

Background: Imaging of gas distribution in the lungs of patients with asthma has been restricted because of the lack of a suitable gaseous contrast agent. Hyperpolarized helium-3 (HHe3) provides a new technique for magnetic resonance imaging of lung diseases.

Objective: We sought to investigate the use of HHe3 gas to image the lungs of patients with moderate or severe asthma and to assess changes in gas distribution after methacholine and exercise challenge.

Constrained modeling for spectroscopic measurement of bi-exponential spin-lattice relaxation of water in vivo.

The (1)H NMR water signal from spectroscopic voxels localized in gray matter contains contributions from tissue and cerebral spinal fluid (CSF). A typically weak CSF signal at short echo times makes separating the tissue and CSF spin-lattice relaxation times (T(1)) difficult, often yielding poor precision in a bi-exponential relaxation model. Simulations show that reducing the variables in the T(1) model by using known signal intensity values significantly improves the precision of the T(1) measurement.

Ventilation-perfusion ratio of signal intensity in human lung using oxygen-enhanced and arterial spin labeling techniques.

This study investigates the distribution of ventilation-perfusion (V/Q) signal intensity (SI) ratios using oxygen-enhanced and arterial spin labeling (ASL) techniques in the lungs of 10 healthy volunteers. Ventilation and perfusion images were simultaneously acquired using the flow-sensitive alternating inversion recovery (FAIR) method as volunteers alternately inhaled room air and 100% oxygen. Images of the T(1) distribution were calculated for five volunteers for both selective (T(1f)) and nonselective (T(1)) inversion.