NMR in Biomedicine

Cover image for Vol. 28 Issue 1

January 2015

Volume 28, Issue 1

Pages i–ii, 1–139

  1. Issue Information

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

      Article first published online: 4 DEC 2014 | DOI: 10.1002/nbm.3204

  2. Research articles

    1. Top of page
    2. Issue Information
    3. Research articles
    1. CEST signal at 2 ppm (CEST@2ppm) from Z-spectral fitting correlates with creatine distribution in brain tumor (pages 1–8)

      Kejia Cai, Anup Singh, Harish Poptani, Weiguo Li, Shaolin Yang, Yang Lu, Hari Hariharan, Xiaohong J. Zhou and Ravinder Reddy

      Article first published online: 8 OCT 2014 | DOI: 10.1002/nbm.3216

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      The chemical exchange saturation transfer (CEST) quantification based on asymmetrical analysis is affected by the semi-solid magnetization transfer asymmetry and the nuclear Overhauser enhancement. To remove these contaminations, we fitted individual contributions to the Z-spectrum. The fitted CEST peak at 2 ppm (CEST@2ppm) was found to correlate with the creatine distribution in brain tumor. This method may have broad implications in cancer bioenergetics.

    2. Increased brain perfusion contrast with T2-prepared intravoxel incoherent motion (T2prep IVIM) MRI (pages 9–16)

      Christian Federau and Kieran O'Brien

      Article first published online: 10 OCT 2014 | DOI: 10.1002/nbm.3223

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      Intravoxel incoherent motion (IVIM) MRI is an intrinsically local and quantitative method to measure brain microvascular perfusion, but is contaminated by partial volume effects with cerebrospinal fluid. In this work, we demonstrate that cerebrospinal fluid can be advantageously suppressed with a T2-weighted inversion recovery magnetization preparation, leading to an increased brain tumor blood volume contrast, and an increased subjective lesion detection and diagnostic confidence.

    3. Real-time assessment of 13C metabolism reveals an early lactate increase in the brain of rats with acute liver failure (pages 17–23)

      Laia Chavarria, Jordi Romero-Giménez, Eva Monteagudo, Silvia Lope-Piedrafita and Juan Cordoba

      Article first published online: 10 OCT 2014 | DOI: 10.1002/nbm.3226

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      Hyperpolarized 13C1-pyruvate was used to study the in vivo metabolism of the acute liver failure model in rats, showing an early detection of the de novo synthesis of lactate when animals had no evident disease. These results suggest that brain lactate is involved in the physiopathology of acute liver failure. Hyperpolarization is a potential non-invasive technique to follow metabolism and, together with the development of 13C-labeled substrates, may clarify the mechanism involved in acute liver failure.

    4. Regional fractional ventilation mapping in spontaneously breathing mice using hyperpolarized 129Xe MRI (pages 24–29)

      Hirohiko Imai, Hironobu Matsumoto, Erika Miyakoshi, Shintaro Okumura, Hideaki Fujiwara and Atsuomi Kimura

      Article first published online: 13 OCT 2014 | DOI: 10.1002/nbm.3222

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      The feasibility of hyperpolarized 129Xe MRI has been investigated for quantitative and regional assessment of ventilation in spontaneously breathing mice. Adopting the multiple ventilation imaging technique modified to the protocol of spontaneous inhalation, we succeeded in acquiring a series of images by varying the number of breaths and mapping the fractional ventilation parameter of r. The r map could visualize the significant dysfunction of ventilation in the emphysematous mouse lung induced by porcine pancreatic elastase.

    5. Accelerated three-dimensional cine phase contrast imaging using randomly undersampled echo planar imaging with compressed sensing reconstruction (pages 30–39)

      Tamer A. Basha, Mehmet Akçakaya, Beth Goddu, Sophie Berg and Reza Nezafat

      Article first published online: 16 OCT 2014 | DOI: 10.1002/nbm.3225

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      An accelerated three-dimensional cine phase contrast MRI sequence was implemented by combining echo planar imaging readout with a randomly undersampled three-dimensional k space. Compressed sensing (CS) reconstruction was then used to reconstruct the whole cine volume. The scan time was reduced by a factor of seven and the quantification results show a good agreement with the standard two-dimensional cine phase contrast.

    6. Towards quantification of pulsed spinlock and CEST at clinical MR scanners: an analytical interleaved saturation–relaxation (ISAR) approach (pages 40–53)

      Volkert Roeloffs, Christian Meyer, Peter Bachert and Moritz Zaiss

      Article first published online: 18 OCT 2014 | DOI: 10.1002/nbm.3192

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      Saturation of a two-pool-CEST system by pulsed spinlock can be modeled by an interleaved saturation–relaxation (ISAR) approach. Taking into account the chemical exchange during the pause is crucial, and leads to an analytical solution that agrees well with the full numerical simulation of the Bloch–McConnell equations for a broad range of values of the system parameters. This analytical solution allows the quantitative evaluation of Z-spectra obtained from creatine model solutions on a clinical 3 T scanner.

    7. Skin sodium measured with 23Na MRI at 7.0 T (pages 54–62)

      Peter Linz, Davide Santoro, Wolfgang Renz, Jan Rieger, Anjuli Ruehle, Jan Ruff, Michael Deimling, Natalia Rakova, Dominik N. Muller, Friedrich C. Luft, Jens Titze and Thoralf Niendorf

      Article first published online: 18 OCT 2014 | DOI: 10.1002/nbm.3224

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      This work demonstrates the feasibility of submillimeter in-plane spatial resolution 23Na MRI in skin at clinically acceptable acquisition times at 7.0 T. Intra-subject variability of human skin Na+ content in the volunteer population was <10.3%. An age-dependent increase in skin Na+ content was observed (r = 0.78). Assigning Na+ stores with 23Na MRI techniques could be improved at 7.0 T compared with current 3.0-T technology.

    8. Measuring renal tissue relaxation times at 7 T (pages 63–69)

      Xiufeng Li, Patrick J. Bolan, Kamil Ugurbil and Gregory J. Metzger

      Article first published online: 23 OCT 2014 | DOI: 10.1002/nbm.3195

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      Renal relaxometry measurements were made at 3 T and 7 T using a magnetization-prepared single-breath-hold fast spin echo imaging method. Reproducibility of measured relaxometry parameters was demonstrated at 7 T while overcoming the challenges of B1+ and B0 inhomogeneity and limitation in peak available B1+ and short-term SAR.

    9. Effects of inversion time on inversion recovery prepared ultrashort echo time (IR-UTE) imaging of bound and pore water in cortical bone (pages 70–78)

      Shihong Li, Lanqing Ma, Eric Y. Chang, Hongda Shao, Jun Chen, Christine B. Chung, Graeme M. Bydder and Jiang Du

      Article first published online: 28 OCT 2014 | DOI: 10.1002/nbm.3228

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      IR-UTE imaging of the tibial midshaft of a 39 year old healthy female volunteer with a TR of 300 ms, a TI of 110 ms, and TE value of 8 µs (A), 0.1 ms (B), 0.2 ms (C), 0.4 ms (D), 0.6 ms (E), 1.0 ms (F), 1.5 ms (G) and 2.5 ms (H) as well as single-component fitting of the bone signal decay (I), which accounted for 99.88% of the signal variance, consistent with only bound water with a T2* of 347 ± 10 µs being detected by the IR-UTE sequence. Residual signals from muscle and fat were better observed at longer TE values due to fast signal decay from cortical bone, which dominated the IR-UTE signal at shorter TE values.

    10. Positive contrast of SPIO-labeled cells by off-resonant reconstruction of 3D radial half-echo bSSFP (pages 79–88)

      Clemens Diwoky, Daniel Liebmann, Bernhard Neumayer, Andreas Reinisch, Florian Knoll, Dirk Strunk and Rudolf Stollberger

      Article first published online: 7 NOV 2014 | DOI: 10.1002/nbm.3229

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      We propose a new cell tracking technique based on 3D radial bSSFP half-echo imaging. Signal recovery of voxels containing paramagnetic loaded cells is achieved by multiple reconstructions of the raw data modulated with an artificial global frequency offset ∆B0add. Background suppression with positive cellular contrast is gained by subtraction of the on-resonant from modulated data. The proposed method is able to remarkably exceed the cellular CNR values known from negative contrast bSSFP, improving the detection limits for labeled cells.

    11. MR elastography and diffusion-weighted imaging of ex vivo prostate cancer: quantitative comparison to histopathology (pages 89–100)

      Ramin S. Sahebjavaher, Guy Nir, Louis O. Gagnon, Joseph Ischia, Edward C. Jones, Silvia D. Chang, Andrew Yung, Mohammad Honarvar, Ladan Fazli, S. Larry Goldenberg, Robert Rohling, Ralph Sinkus, Piotr Kozlowski and Septimiu E. Salcudean

      Article first published online: 10 NOV 2014 | DOI: 10.1002/nbm.3203

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      We report the design of a new electromechanical transducer (a) for MR elastography (MRE) studies – in this case for studies of ex vivo prostate glands (b). Using this system we performed a preliminary patient study (c) to show that mono- and multi-frequency MRE examinations – alone and in combination with diffusion-weighted imaging – can improve the diagnostic performance of cancer detection. More experiments are needed in light of the effect of tissue fixation.

    12. FID navigator-based MR thermometry method to monitor small temperature changes in the brain of ventilated animals (pages 101–107)

      Nicolas Boulant, Michel Bottlaender, Lynn Uhrig, Eric Giacomini, Michel Luong, Alexis Amadon, Aurélien Massire, Benoît Larrat and Alexandre Vignaud

      Article first published online: 11 NOV 2014 | DOI: 10.1002/nbm.3232

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      An MR thermometry method is proposed for measuring in vivo small temperature changes engendered by RF heat sources on ventilated animals. The stability of the main magnetic field as well as the variations induced by breathing are characterized during a first monitoring stage. Suitable post-processing based on this data then allows us to correct for these effects during RF heating. Experiments performed at 7 T on an anesthetized baboon and with a dedicated RF heating setup reveal a precision around 0.1°C.

    13. 1H MRS characterization of neurochemical profiles in orthotopic mouse models of human brain tumors (pages 108–115)

      Keith M. Hulsey, Tomoyuki Mashimo, Abhishek Banerjee, Todd C. Soesbe, Jeffrey S. Spence, Vamsidhara Vemireddy, Elizabeth A. Maher, Robert M. Bachoo and Changho Choi

      Article first published online: 13 NOV 2014 | DOI: 10.1002/nbm.3231

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      We report an in vivo 1H MRS study of the neurochemical profile of a human orthotopic tumor mouse model of human GBM in mice. The tumors had significantly lower concentrations of creatine, GABA, glutamate, N-acetylaspartate, aspartate, and lipids/macromolecules than did the brains of healthy mice. The glycine and lactate levels were significantly higher in tumors than in the controls.

    14. Analysis of left ventricular function of the mouse heart during experimentally induced hyperthyroidism and recovery (pages 116–123)

      Neele Saskia Hübner, Annette Merkle, Bernd Jung, Dominik von Elverfeldt and Laura-Adela Harsan

      Article first published online: 13 NOV 2014 | DOI: 10.1002/nbm.3233

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      High-field mouse cardiac MRI was performed to monitor and follow-up longitudinally the effects of long-term thyroid hormone (T3) administration, inducing hyperthyroidism in adolescent and adult female mice. Sustained cycles of T3 administration and arrest lead to an impairment of cardiac performance with a decline in ejection fraction and wall thickening. Treatment cessation for 3 weeks resulted in partly restored cardiac performance in adolescent mice but not in adult animals, indicating a presence of chronically developed heart pathology.

    15. MR elastography of prostate cancer: quantitative comparison with histopathology and repeatability of methods (pages 124–139)

      Ramin S. Sahebjavaher, Guy Nir, Mohammad Honarvar, Louis O. Gagnon, Joseph Ischia, Edward C. Jones, Silvia D. Chang, Ladan Fazli, S. Larry Goldenberg, Robert Rohling, Piotr Kozlowski, Ralph Sinkus and Septimiu E. Salcudean

      Article first published online: 14 NOV 2014 | DOI: 10.1002/nbm.3218

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      This study presents the first MR elastography study of prostate cancer that compares imaging with full-mount histopathology (Gleason score). Though the overall AUC was poor due to many false positives, a significant difference (p < 0.05) between normal and cancerous tissue was identified in most cases. The repeatability of the method was tested in phantoms and volunteers, and it was observed that the inversion algorithm was sensitive to (i) vibration amplitude and displacement nodes, which shifted with small changes in excitation frequency, and (ii) misalignment of the 3D wave field due to slight subject movement.

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