Room 155 EF

13:30 - 15:30

Moderators:

Houchun Harry Hu, Martin P. Smith

Houchun H. Hu
 

Patricia M. Nunes¹, Alan J. Wright¹, Andor Veltien¹, Jack JA van Asten¹, Cees J. Tack², John G. Jones³, and Arend Heerschap^1
1Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, Gelderland, Netherlands, ²Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, Gelderland, Netherlands,³Center for Neurosciences and Cell Biology, Coimbra, Coimbra, Portugal

We investigated in vivo the effects of isocaloric fructose and glucose feeding of mice over 8 weeks on ectopic lipid deposition and hepatic energy status by MRS. Hepatic lipid sources were resolved into dietary, which was investigated in vivo with ₁H{¹³C}MRS after an oral bolus of [U-¹³C]lipids, and de novo lipogenesis which was assessed by ²H NMR spectroscopy using ²H₂O as tracer. Isocaloric fructose feeding had no effect on intramyocellular lipids, but significantly increased hepatic lipids, most likely by stimulating de novo lipogenesis and not by promoting dietary fat uptake. This occurs without expense of net hepatic energy, as shown by ³¹P MRS, unlike acute doses of fructose.

Koji Sagiyama¹, Orson W. Moe², and Masaya Takahashi^1
1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, United States, ²Mineral Metabolism/Internal Medicine, University of Texas Southwestern Medical Center, Dalla, Texas, United States

Our previous studies in murine models of unilateral ureteral obstruction and dietary phosphate overload have shown excellent correlation between MRI and kidney histopathology, where the apparent diffusion constant (ADC) determined by DW-MRI inversely correlates with the severity of fibrosis. It has also been shown that blood oxygen level dependent (BOLD) MRI measures renal hypoxia where hypoxic tissue shows lower T2*. The purpose of this study was to test our hypothesis that a combination of DW- and BOLD-MRI would reflect histopathological and functional changes in vivo in the kidney with type II diabetes.

Deng Mao¹, Lisa Krishnamurthy¹, and Hanzhang Lu^1
1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, United States

Liver consumes 20 percent of the total resting state oxygen consumption and oxygen supply is important for its functionality and viability. However, the current methods measuring hepatic oxygen metabolism rate (HMRO2) are limited due to invasiveness. Therefore, a new and non-invasive way to measure HMRO2 was first developed by us. This method measures the oxygenation level of hepatic vein and hepatic portal vein by a newly established sequence called T2-Relaxation-Under-Spin-Tagging (TRUST). Plus using phase contract MRI to measure portal vein blood flow, HMRO2 can be calculated based on Fick principal. The preliminary results demonstrate a proof-of principle for the method.

Shuo Zhang¹, Alexander Beham², Arun Joseph¹, Henrik Forster², Aaron Niebergall¹, Martin Uecker³, and Jens Frahm^1
1Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut fuer biophysikalische Chemie, Goettingen, Niedersachsen, Germany, ²Allgemein- und Visceralchirurgie, University Hospital Goettingen, Goettingen, Lower Saxony, Germany, ³Dept. of Electrical Engineering and Computer Sciences, University of California, Berkeley, California, United States

Previous studies of esophageal function using conventional clinical methods suffer mainly from invasiveness and limited soft-tissue contrast. Here, we applied the recently introduced real-time MRI technique based on undersampled radial FLASH and nonlinear inversion. Typical T1-weighted images had an in-plane resolution of 2.0 mm and acquisition times of 50 ms (20 fps), and are free from susceptibility or motion artifacts. The movies successfully resolved the transport of pineapple juice as bolus through the esophagus from its thoracic part to sphincter and to stomach. Preliminary results also demonstrated potential to visualize gastroesophageal reflux, which promises a useful tool for disease diagnosis.

Alex Menys¹, Stuart A. Taylor¹, Anton Emmanuel², Asia Ahmed¹, Andrew Plumb¹, Freddy Odille^3,4, Ahsan Alam², Steve Halligan¹, and David Atkinson^1
1Centre for Medical Imaging, UCL, London, UK, United Kingdom, ²GI Physiology UCLH, London, UK, United Kingdom, ³INSERM U947, Nancy, Nancy, France, ⁴IADI, Université de Lorraine, Nancy, Nancy, France

Aberrant small bowel motility is described in a range of diseases including chronic intestinal pseudo-obstruction, Crohn’s disease and irritable bowel syndrome. Few tools exist to investigate abnormal motility and those that do are often invasive and fail to assess the whole of the small bowel. This article describes the validation of a novel MRI technique which safely and non-invasively quantifies global small bowel motility, reporting within-subject repeatability in healthy human subjects and sensitivity to the motility altering drugs butylscopolamine and neostigmine.

Devkumar Mustafi¹, Sheng-Ru Shiou², Xiaobing Fan³, Erica Markiewicz¹, Gregory S. Karczmar¹, and Erika Claud^4
1Radiology, The University of Chicago, Chicago, Illinois, United States, ²Pediatrics, The University of Chicago, Chicago, Illinois, United States, ³Radiology, University of Chicago, Chicago, Illinois, United States, ⁴Pediatrics and Medicine, The University of Chicago, Chicago, Illinois, United States

Neonatal necrotizing enterocolitis (NEC) is a poorly understood, life-threatening illness afflicting premature infants. The pathophysiology for this disease is also poorly understood. Moreover, there is no suitable animal model or appropriate method for monitoring the disease non-invasively. Using high-resolution anatomical and diffusion weighted imaging, including pixel-by-pixel T2 and ADC maps, in conjunction with the gold-standard histological images of the excised ileal tissue samples and the measured levels of intestinal inflammatory cytokines, we have detected NEC in 2-4 days old rat pups. We have also assessed intestinal injuries prior to clinical symptoms in a physiologic rat pup model of NEC.

Gemma Louise Chaddock^1
1Physics & Astronomy, The University of Nottingham, Nottingham, Nottinghamshire, United Kingdom

We developed a novel MRI technique to measure colonic transit time using MRI marker capsules. We validated this new method against the gold standard X-ray radiopaque markers. 20 subjects took part in the study twice (test-retest). On each study week they swallowed 5 MRI transit marker capsules 24 hours before undergoing an MRI scan. Subjects also undertook the X-ray test, swallowing 20 radiopaque markers on 3 consecutive days with a single abdominal x-ray taken on day 4 as validated in the literature. We found that the MRI transit marker and radiopaque marker results correlated well (Spearman’s r= 0.85, p<0.0001).This could provide an alternative test for measuring colonic transit which is simple to carry out and interpret, convenient, non invasive, and does not involve exposure to ionising radiation.

Nienke Lynn Hansen¹, Alexandra Barabasch¹, Martina Distelmaier¹, Alexander Ciritsis², Nicolas Kuehnert³, Jens Otto³, Joachim Conze³, Christiane K. Kuhl¹, and Nils Andreas Kraemer^1
1Department of Diagnostic and Interventional Radiology, RWTH Aachen University Hospital, Aachen, NRW, Germany, ²Department of Diagnostic and Interventional Radiology, RWTH University Hospital, Aachen, NRW, Germany, ³Department of Surgery, RWTH Aachen University Hospital, Aachen, NRW, Germany

Thirteen patients surgically treated for inguinal hernias using iron-loaded visible mesh implants were examined by MRI on the first postsurgical day. Two conventional gradient echo sequences and a T2-weighted turbo-spin echo (TSE) sequence were used. To achieve best mesh visualization, GRE sequences were preferred, whereas anatomy was depicted best using TSE. Consequently, for optimal diagnosis we propose a combination of both types of sequences.

Shantanu Sinha¹, Valmik Bhargava², Melissa Ledgerwood², and Ravinder Mittal^2
1Radiology, University of California at San Diego, San Diego, C, United States, ²Medicine, University of California at San Diego, San Diego, CA, United States

The External Anal Sphincter (EAS) is the most commonly affected muscle in patients with fecal incontinence. Current belief is that the EAS is “donut shaped” ; we hypothesize that the EAS instead has a “purse-string” morphology with transverse perinei being extensions of the EAS muscles. Such structure contracts in a circumferential manner to generate higher anal canal pressure than the circular shape and has significant relevance for the effects of lateral episiotomy on EAS function. We report a combination of multiple imaging techniques including 3D-ultrasound, structural MRI and fiber tractography that strongly suggest that EAS is configured as a “purse-string”.