NMR in Biomedicine

Cover image for Vol. 25 Issue 5

May 2012

Volume 25, Issue 5

Pages i–iii, 695–812

  1. Issue Information

    1. Top of page
    2. Issue Information
    3. Review Articles
    4. Research Articles
    1. Issue Information (pages i–iii)

      Version of Record online: 10 APR 2012 | DOI: 10.1002/nbm.2754

  2. Review Articles

    1. Top of page
    2. Issue Information
    3. Review Articles
    4. Research Articles
    1. 7-T MR—from research to clinical applications? (pages 695–716)

      Ewald Moser, Freddy Stahlberg, Mark E. Ladd and Siegfried Trattnig

      Version of Record online: 21 NOV 2011 | DOI: 10.1002/nbm.1794

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      Over 20 000 MR systems are currently installed worldwide, about 70% ≤1.5 T, 30% 3 T and only 0.2% 7 T or higher. However, we provide a rationale for a shift to higher fields and review the current clinical potential of 1H MRI, as well as 23Na MRI and 31P MRS. We also discuss current challenges and relevant safety issues. We conclude by identifying areas of 7-T research with the highest potential to become some of the first clinical applications to benefit patients.

      One example is cartilage imaging at 7 T: T2 (a) and T2* (b) mapping of the patella in the axial plane visualises the zonal variation of cartilage based on the collagen fibre network in articular cartilage.

  3. Research Articles

    1. Top of page
    2. Issue Information
    3. Review Articles
    4. Research Articles
    1. Spatial location and strength of BOLD activation in high-spatial-resolution fMRI of the motor cortex: a comparison of spin echo and gradient echo fMRI at 7 T (pages 717–725)

      J. Harmer, R. M. Sanchez-Panchuelo, R. Bowtell and S. T. Francis

      Version of Record online: 22 SEP 2011 | DOI: 10.1002/nbm.1783

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      The spatial locations of, and signal changes in, the motor cortex for gradient echo and spin echo functional MRI data at ultrahigh field (7 T) and high spatial resolution (1.5 mm isotropic) were compared. The spin echo blood oxygenation level-dependent signal increased linearly with TE, with 45 ms being optimal. Gradient echo activation maps contained more voxels overlying venous blood vessels. We identified a dark band in the precentral gyrus on spin echo images corresponding to shortened T2/T2*.

    2. Phase contrast MRI is an early marker of micrometastatic breast cancer development in the rat brain (pages 726–736)

      Matthew D. Budde, Eric Gold, E. Kay Jordan, Melissa Smith-Brown and Joseph A. Frank

      Version of Record online: 22 SEP 2011 | DOI: 10.1002/nbm.1786

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      Phase contrast MRI is an intrinsic contrast exquisitely sensitive to deoxyhemoglobin. In an experimental model of metastatic breast cancer in the brain, phase images were more sensitive than magnitude images to vascular abnormalities in tumors. Serial phase contrast changes demonstrated the early growth of micrometastatic breast cancer in the brain, suggestive of vascular remodeling in the absence of angiogenesis in this infiltrative and rapidly growing tumor.

    3. Imaging and quantification of metastatic melanoma cells in lymph nodes with a ferritin MR reporter in living mice (pages 737–745)

      Seung Hong Choi, Hye Rim Cho, Hoe Suk Kim, Young Hwa Kim, Keon Wook Kang, Hyeonjin Kim and Woo Kyung Moon

      Version of Record online: 28 NOV 2011 | DOI: 10.1002/nbm.1788

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      This is the first MRI study to both visualize and quantify ferritin gene expression in lymph node (LN) metastasis. R50 (i.e. median) values calculated from cumulative T2* histograms correlated well with histologically measured metastatic burden in LNs. Potential future applications of this technique include the tracking of tumor progression and metastasis and the monitoring of transgene expression in deep tissues.

    4. Noninvasive imaging identifies new roles for cyclooxygenase-2 in choline and lipid metabolism of human breast cancer cells (pages 746–754)

      Tariq Shah, Ioannis Stasinopoulos, Flonne Wildes, Samata Kakkad, Dmitri Artemov and Zaver M. Bhujwalla

      Version of Record online: 22 SEP 2011 | DOI: 10.1002/nbm.1789

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      Cyclooxygenase-2 (COX-2)-silenced cells showed significantly decreased invasion relative to COX-2-containing parental cells, consistent with reduced expression of several invasion-associated genes. We identified a new role for COX-2 in mediating changes in choline phospholipid metabolism and established that choline kinase expression is partly dependent on COX-2 function. COX-2 silencing resulted in a significant decrease in phosphocholine and total choline and an increase in lipids. COX-2 silencing transformed metabolite patterns to those characteristic of less aggressive cancer cells.

    5. A phase and frequency alignment protocol for 1H MRSI data of the prostate (pages 755–765)

      Alan J. Wright, Lutgarde M. C. Buydens and Arend Heerschap

      Version of Record online: 26 SEP 2011 | DOI: 10.1002/nbm.1790

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      Three-dimensional 1H MRSI is a promising tool for investigations into the identification, localisation and staging of prostate cancer. We have developed a peak alignment algorithm that aligns the frequency and phase variations in the spectra of these datasets. The procedure is fully automated and adapted to the specific challenges of prostate cancer datasets.

    6. Considerations in high-resolution skeletal muscle diffusion tensor imaging using single-shot echo planar imaging with stimulated-echo preparation and sensitivity encoding (pages 766–778)

      Dimitrios C. Karampinos, Suchandrima Banerjee, Kevin F. King, Thomas M. Link and Sharmila Majumdar

      Version of Record online: 11 NOV 2011 | DOI: 10.1002/nbm.1791

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      In the present work, the reduction factor and diffusion weighting time are theoretically optimized with respect to the signal-to-noise ratio (SNR) in a scheme combining eddy current-compensated diffusion-weighted stimulated-echo preparation with sensitivity encoding (SENSE). Trade-offs for the proposed scheme are presented in order to maintain good SNR properties and reduce the sensitivity to distortions, T2* blurring and tissue incoherent motion in skeletal muscle single-shot diffusion-weighted echo planar imaging. In vivo results demonstrate significant benefit from the reduction in partial volume effects on the resolution of multi-pennate muscles and muscles with small cross-sections in skeletal muscle diffusion tensor imaging.

    7. Comparison of relative cerebral blood flow maps using pseudo-continuous arterial spin labeling and single photon emission computed tomography (pages 779–786)

      Peiying Liu, Jinsoo Uh, Michael D. Devous, Bryon Adinoff and Hanzhang Lu

      Version of Record online: 2 DEC 2011 | DOI: 10.1002/nbm.1792

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      Arterial transit times in arterial spin labeling were determined using a bolus tracking approach. The use of tissue-specific parameters in the one-compartment pseudo-continuous arterial spin labeling (PCASL) model was helpful in improving the correspondence between PCASL and single photon emission computed tomography (SPECT) results. Despite the need for further improvement in quantification, PCASL-derived relative cerebral blood flow after accounting for transit time offers an excellent choice for a fast, convenient and noninvasive measurement of perfusion in the human brain.

    8. Interstitial fluid pressure correlates with intravoxel incoherent motion imaging metrics in a mouse mammary carcinoma model (pages 787–794)

      Sungheon Kim, Lindsey Decarlo, Gene Y. Cho, Jens H. Jensen, Daniel K. Sodickson, Linda Moy, Silvia Formenti, Robert J. Schneider, Judith D. Goldberg and Eric E. Sigmund

      Version of Record online: 9 NOV 2011 | DOI: 10.1002/nbm.1793

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      Tumor interstitial fluid pressure (IFP) strongly correlates with the median pseudo-diffusivity (Dp) of apparent vascular voxels (r = 0.76, p = 0.02) and with the median product of the perfusion fraction and pseudo-diffusivity (fpDp) of apparent vascular voxels (r = 0.77, p = 0.02). This study represents the first direct comparison of intravoxel incoherent motion (IVIM) metrics with IFP, with the results supporting the feasibility of using IVIM diffusion-weighted imaging metrics as noninvasive biomarkers for tumor IFP.

    9. The importance of axonal undulation in diffusion MR measurements: a Monte Carlo simulation study (pages 795–805)

      Markus Nilsson, Jimmy Lätt, Freddy Ståhlberg, Danielle van Westen and Håkan Hagslätt

      Version of Record online: 21 OCT 2011 | DOI: 10.1002/nbm.1795

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      Axons following wave-like undulating courses are a general feature of extracranial nerve segments, but are also found in some intracranial nervous tissue. The presence of undulation influences all parameters derived from a diffusion MR measurement, according to Monte Carlo simulations. Stretching or compression of tissue comprising undulating axons affects the fractional anisotropy (FA).

    10. Regional homogeneity abnormalities in patients with interictal migraine without aura: a resting-state study (pages 806–812)

      Dahua Yu, Kai Yuan, Ling Zhao, Limei Zhao, Minghao Dong, Peng Liu, Guihong Wang, Jixin Liu, Jinbo Sun, Guangyu Zhou, Karen M. von Deneen, Fanrong Liang, Wei Qin and Jie Tian

      Version of Record online: 21 OCT 2011 | DOI: 10.1002/nbm.1796

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      We employed a regional homogeneity (ReHo) method to analyze the local features of spontaneous brain activity in 26 patients with migraine without aura and 26 healthy volunteers during the resting state. Patients with migraine without aura showed a significant decrease in ReHo values in the right rostral anterior cingulate cortex (rACC), the prefrontal cortex (PFC), the orbitofrontal cortex (OFC) and the supplementary motor area (SMA). In addition, we found that ReHo values were negatively correlated with the duration of disease in the right rACC and PFC.