NMR in Biomedicine

Cover image for Vol. 25 Issue 11

November 2012

Volume 25, Issue 11

Pages i–ii, 1209–1309

  1. Issue information

    1. Top of page
    2. Issue information
    3. Research articles
    4. Rapid communication
    1. Issue Information (pages i–ii)

      Article first published online: 25 OCT 2012 | DOI: 10.1002/nbm.2760

  2. Research articles

    1. Top of page
    2. Issue information
    3. Research articles
    4. Rapid communication
    1. Optimization of flow-sensitive alternating inversion recovery (FAIR) for perfusion functional MRI of rodent brain (pages 1209–1216)

      Fatima A. Nasrallah, Eugene L. Q. Lee and Kai-Hsiang Chuang

      Article first published online: 26 MAR 2012 | DOI: 10.1002/nbm.2790

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      In this study, flow-sensitive alternating inversion recovery (FAIR) pulsed arterial spin labeling was optimized for functional MRI of rat brain. Coil coverage was optimized to yield a 38.3% increase in perfusion signal compared with the isocenter position; 53.3% gain was achieved using optimized TR and inversion time compared with a long TR.

    2. Combined use of filtered and edited 1H NMR spectroscopy to detect 13C-enriched compounds in complex mixtures (pages 1217–1223)

      P. W. A. Howe, Z. Ament, K. Knowles, J. L. Griffin and J. Wright

      Article first published online: 8 MAR 2012 | DOI: 10.1002/nbm.2791

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      The natural abundance 13C background present in biological extracts hinders the detection of 13C enriched xenobiotics. This problem can be overcome by quantitative analysis of 1D or 2D 13C filtered and 13C edited proton NMR spectra. The approach is demonstrated by the detection of sub-microgram amounts of 13C enriched Phenacetin in liver microsome extracts.

    3. Group-averaged anatomical connectivity mapping for improved human white matter pathway visualisation (pages 1224–1233)

      Mara Cercignani, Karl Embleton, Geoffrey J M Parker and Marco Bozzali

      Article first published online: 21 MAR 2012 | DOI: 10.1002/nbm.2793

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      Anatomical connectivity mapping (ACM) was obtained by initiating diffusion tractography from all parenchymal voxels and by counting the number of streamlines passing through each voxel. We present group-averaged ACMs providing complementary information and greater anatomical detail than fractional anisotropy, enabling white matter bundles lying next to each other to be discriminated. For example, the superior cerebellar peduncles (SCP), the anterior thalamic radiation (ATR) and the medial lemniscus (mLemn) were clearly identified even where they ran parallel to each other.

    4. Metabolism of [U-13C]glucose in human brain tumors in vivo (pages 1234–1244)

      Elizabeth A. Maher, Isaac Marin-Valencia, Robert M. Bachoo, Tomoyuki Mashimo, Jack Raisanen, Kimmo J. Hatanpaa, Ashish Jindal, F. Mark Jeffrey, Changho Choi, Christopher Madden, Dana Mathews, Juan M. Pascual, Bruce E. Mickey, Craig R. Malloy and Ralph J. DeBerardinis

      Article first published online: 15 MAR 2012 | DOI: 10.1002/nbm.2794

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      Metabolic reprogramming is a hallmark of cancer cells, yet few studies have analyzed the metabolism of human tumors in vivo. Eleven patients with solitary brain tumors were infused with [U-13C]glucose during surgical resection, and metabolites extracted from the tumors were analyzed by 13C NMR spectroscopy. Primary tumors and brain metastases used glucose to supply many metabolic pathways, including glycolysis, the tricarboxylic acid cycle and amino acid synthesis.

    5. Phase-adjusted echo time (PATE)-averaging 1H MRS: application for improved glutamine quantification at 2.89 T (pages 1245–1252)

      Andrew P. Prescot, Todd Richards, Stephen R. Dager, Changho Choi and Perry F. Renshaw

      Article first published online: 12 MAR 2012 | DOI: 10.1002/nbm.2795

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      A novel 1H MRS post-processing method, termed phase-adjusted echo time (PATE) averaging, was developed to improve the quantification of glutamine at 2.89 T. The technique works by applying an optimal TE-specific phase term, which is derived from simulation procedures, prior to averaging over TE space. The potential clinical utility of PATE-averaging 1H MRS was evaluated using data acquired from the human frontal lobe, and the test-retest reliability of brain glutamine levels was comparable with that of existing methods for both within-subject (9%) and inter-subject (14%) measures.

    6. Lipid biomarkers of glioma cell growth arrest and cell death detected by 1H magic angle spinning MRS (pages 1253–1262)

      Ladan Mirbahai, Martin Wilson, Christopher S. Shaw, Carmel McConville, Roger D. G. Malcomson, Risto A. Kauppinen and Andrew C. Peet

      Article first published online: 8 MAR 2012 | DOI: 10.1002/nbm.2796

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      In a detailed quantitative analysis, an increase in MRS-visible lipids was identified during exposure of BT4C glioma cells to the chemotherapeutic drug cisplatin. The lipid signals were associated with cytoplasmic lipid droplets accumulating in cells undergoing cell cycle arrest prior to exhibiting indicators of cell death. This study provides further evidence that in vivo MRS lipids may offer a surrogate marker of the early response to cytotoxic anti-cancer drugs for which tumour size on imaging is a poor indicator of treatment.

    7. Diffusion tensor quantification and cognitive correlates of the macrostructure and microstructure of the corpus callosum in typically developing and dyslexic children (pages 1263–1270)

      Khader M. Hasan, David L. Molfese, Indika S. Walimuni, Karla K. Stuebing, Andrew C. Papanicolaou, Ponnada A. Narayana and Jack M. Fletcher

      Article first published online: 13 MAR 2012 | DOI: 10.1002/nbm.2797

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      Validated diffusion tensor imaging (DTI)-based segmentation methods (A) were applied to the midsagittal corpus callosum (CC) of 11 healthy (typically developing readers, TDR), 24 dyslexic (DX) and 15 age-matched children with fluency and comprehension difficulties (CF) (B). Significant differences were noted in posterior CC areas (C) and corresponding DTI metrics, such as fractional anisotropy (FA) (D) and radial diffusivity, in which correlations with reading scores were also noted (E). Our results indicate that the two hemispheres communicate in reading disorders. Our work contributes towards an understanding of the neurobiology of reading disorders.

    8. Lactate and glycine—potential MR biomarkers of prognosis in estrogen receptor-positive breast cancers (pages 1271–1279)

      Guro F. Giskeødegård, Steinar Lundgren, Beathe Sitter, Hans E. Fjøsne, Geert Postma, Lutgarde M. C. Buydens, Ingrid S. Gribbestad and Tone F. Bathen

      Article first published online: 8 MAR 2012 | DOI: 10.1002/nbm.2798

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      In this study, we have revealed differences in the metabolite profiles of breast cancer biopsies (n = 98) from 5-year survivors and nonsurvivors using high-resolution magic angle spinning MRS. The metabolites lactate and glycine were more strongly expressed in nonsurvivors and are potential biomarkers for breast cancer prognosis. MR metabolomics may serve as a tool for the evaluation of prognosis in patients with breast cancer

    9. Inhibition of the sodium–calcium exchanger via SEA0400 altered manganese-induced T1 changes in isolated perfused rat hearts (pages 1280–1285)

      Ya Chen, Kevin Payne, Vindya S. Perara, Songping Huang, Akemichi Baba, Toshio Matsuda and Xin Yu

      Article first published online: 21 MAR 2012 | DOI: 10.1002/nbm.2799

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      In this study, the impact of the sodium–calcium exchanger (NCX) on the manganese-enhanced MRI (MEMRI) signal was evaluated in isolated perfused rat hearts. The results show that NCX inhibition with 1 µ m SEA0400 leads to an increase in manganese retention and altered kinetics of T1 changes during manganese perfusion and wash-out. Hence, MEMRI may provide an in vivo imaging method for the simultaneous evaluation of the calcium uptake and efflux via L-type calcium channels and NCX by measuring the dynamics of manganese-induced T1 changes.

    10. Comparison of kinetic models for analysis of pyruvate-to-lactate exchange by hyperpolarized 13C NMR (pages 1286–1294)

      Crystal Harrison, Chendong Yang, Ashish Jindal, Ralph J. DeBerardinis, M. A. Hooshyar, Matthew Merritt, A. Dean Sherry and Craig R. Malloy

      Article first published online: 26 MAR 2012 | DOI: 10.1002/nbm.2801

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      Analyses of six different metabolic models were compared for the extraction of the flux of hyperpolarized (HP) [1-13C1]pyruvate through lactate dehydrogenase using frequency-selective double-Gaussian observe pulses to conserve polarization in pyruvate. Isotopomer data obtained by mass spectrometry on the same cells provided evidence of intracellular and extracellular lactate pools. The inclusion of both pools did not affect the calculated flux values obtained from HP data alone. Exchange and net flux models resulted in accurate values, but only the exchange model predicted the lactate enrichment.

    11. Diffusion kurtosis imaging and log-normal distribution function imaging enhance the visualisation of lesions in animal stroke models (pages 1295–1304)

      Farida Grinberg, Luisa Ciobanu, Ezequiel Farrher and N. Jon Shah

      Article first published online: 27 MAR 2012 | DOI: 10.1002/nbm.2802

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      We report a case study of a stroke model in animals using two methods of quantification of diffusion: diffusion kurtosis imaging and log-normal distribution function imaging. It is demonstrated that the metrics quantifying the degree of deviations from the exponential attenuation undergo essentially larger changes in the ischaemic lesions in the subacute phase than do the parameters quantifying the apparent diffusivity itself. As a result, both methods provide a dramatic enhancement of the visualisation contrast in comparison with conventional diffusion tensor imaging.

  3. Rapid communication

    1. Top of page
    2. Issue information
    3. Research articles
    4. Rapid communication
    1. Exchange rates of creatine kinase metabolites: feasibility of imaging creatine by chemical exchange saturation transfer MRI (pages 1305–1309)

      Mohammad Haris, Ravi Prakash Reddy Nanga, Anup Singh, Kejia Cai, Feliks Kogan, Hari Hariharan and Ravinder Reddy

      Article first published online: 20 MAR 2012 | DOI: 10.1002/nbm.2792

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      Creatine (Cr), phosphocreatine (PCr), adensine-5-triphosphate (ATP) and adensine-5-diphosphate (ADP) are the major metabolites of the enzyme creatine kinase. At physiological temperature and pH, the exchange rate of amine protons in Cr was found to be 7-8 times higher than PCr, ATP and ADP. Higher exchange rate in Cr is associated with lower pKa value suggesting the faster dissociation of its amine protons when compared to PCr, ATP and ADP. Chemical exchange saturation transfer MR imaging of these metabolites in vitro in phantoms displayed predominant contrast from Cr and negligible contribution from PCr, ATP and ADP. These results provide a new method to perform high resolution proton imaging of Cr without any contamination from PCr.