NMR in Biomedicine

Cover image for Vol. 29 Issue 5

Early View (Online Version of Record published before inclusion in an issue)

Impact Factor: 3.044

ISI Journal Citation Reports © Ranking: 2014: 9/44 (Spectroscopy); 24/125 (Radiology Nuclear Medicine & Medical Imaging); 27/73 (Biophysics)

Online ISSN: 1099-1492

Associated Title(s): Contrast Media & Molecular Imaging

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  1. 1 - 48
  1. Research articles

    1. Intraventricular temperature measured by diffusion-weighted imaging compared with brain parenchymal temperature measured by MRS in vivo

      Kaoru Sumida, Noriko Sato, Miho Ota, Koji Sakai, Daichi Sone, Kota Yokoyama, Yukio Kimura, Norihide Maikusa, Etsuko Imabayashi, Hiroshi Matsuda, Akira Kunimatsu and Kuni Ohtomo

      Article first published online: 29 APR 2016 | DOI: 10.1002/nbm.3542

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      The temperature of the intraventricular cerebrospinal fluid (Tv) calculated by MR diffusion-weighted imaging was compared with that of brain parenchyma (Tp) using MRS in 35 healthy volunteers, and there were significant positive correlations between them. The correlation was also significant after correction for tympanic temperature (Tt). Negative correlations were found between Tv and age and Tp and age in males, but not in females.

  2. Special issue review articles

    1. Iron quantification with susceptibility

      Stefan Ropele and Christian Langkammer

      Article first published online: 27 APR 2016 | DOI: 10.1002/nbm.3534

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      Iron in tissue can cause local and non-local changes of the magnetic field, which strongly depend on the spin state and valence of its electrons in the iron compound. Quantitative susceptibility mapping allows to assess the iron content and typically shows a good linear relationship with iron concentration. Larger uncertainties may arise in myelinated fibers and in the presence of mineralized iron with unknown magnetic phases such as hemosiderin or hemozoin.

  3. Research articles

    1. Characterization of clear cell renal cell carcinoma with diffusion kurtosis imaging: correlation between diffusion kurtosis parameters and tumor cellularity

      Yongming Dai, Qiuying Yao, Guangyu Wu, Dongmei Wu, Lianming Wu, Li Zhu, Rong Xue and Jianrong Xu

      Article first published online: 27 APR 2016 | DOI: 10.1002/nbm.3535

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      A cohort of 59 patients with clear cell renal cell carcinoma was evaluated with diffusion kurtosis imaging (DKI). The quantitatively measured DKI-related parameters, mean diffusion coefficient (MD) and mean diffusion kurtosis (MK), were shown to be relevant to tumor grade and to correlate with tumor cellularity. This is the first study to use DKI for renal disease evaluation.

    2. Validation of a semi-automatic co-registration of MRI scans in patients with brain tumors during treatment follow-up

      Anouk van der Hoorn, Jiun-Lin Yan, Timothy J. Larkin, Natalie R. Boonzaier, Tomasz Matys and Stephen J. Price

      Article first published online: 27 APR 2016 | DOI: 10.1002/nbm.3538

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      A two-stage semi-automatic non-linear co-registration method was proposed to co-register brain MRI with high-grade glioma before and after operation. The targeted registration error showed fair deviation of both co-registered postoperative and follow-up recurrence images. A mean 3D structural similarity also demonstrated optimal results.

  4. Special issue review articles

    1. Susceptibility tensor imaging (STI) of the brain

      Wei Li, Chunlei Liu, Timothy Q. Duong, Peter C. M. van Zijl and Xu Li

      Article first published online: 27 APR 2016 | DOI: 10.1002/nbm.3540

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      Susceptibility tensor imaging (STI) is a recently developed MRI technique that allows quantitative determination of orientation-independent magnetic susceptibility parameters from gradient echo signal phase. By modeling the magnetic susceptibility of each voxel as a symmetric rank-2 tensor, individual magnetic susceptibility tensor elements as well as the magnetic susceptibility anisotropy (MSA) can be determined for brain tissues. Similar to diffusion tensor imaging (DTI), STI allows mapping of brain white matter fiber orientations and reconstruction of 3D white matter pathways using the principal eigenvectors of the susceptibility tensor.

  5. Research articles

    1. Separation of collagen-bound and porous bone water transverse relaxation in mice: proposal of a multi-step approach

      Magda Marcon, Daniel Keller, Moritz C. Wurnig, Christian Eberhardt, Markus Weiger, Daniel Eberli and Andreas Boss

      Article first published online: 26 APR 2016 | DOI: 10.1002/nbm.3533

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      The separation and quantification of collagen-bound and pore water in the cortical bone signal are important as a result of their different contributions to bone mechanical properties. Ultrashort TE (UTE) imaging offers the potential to separate the two components. We demonstrate that, in mice, UTE sequences are suitable for the separation and quantification of collagen-bound and pore water signals in cortical bone. Moreover, we propose a new multi-step approach to improve the fitting stability of the parameters.

    2. Tract-specific and age-related variations of the spinal cord microstructure: a multi-parametric MRI study using diffusion tensor imaging (DTI) and inhomogeneous magnetization transfer (ihMT)

      Manuel Taso, Olivier M. Girard, Guillaume Duhamel, Arnaud Le Troter, Thorsten Feiweier, Maxime Guye, Jean-Philippe Ranjeva and Virginie Callot

      Article first published online: 21 APR 2016 | DOI: 10.1002/nbm.3530

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      Diffusion tensor imaging and inhomogeneous magnetization transfer acquisitions were combined with a spinal cord (SC) atlas-based post-processing pipeline in order to refine the characterization of the normal SC microstructure. Differences between upper and lower vertebral levels as well as tract-specific structural differences were emphasized. Age-related tissue destructuration was also highlighted. This multiparametric approach holds great promise for improving the investigation of the neural damage mechanisms occurring in SC pathologies.

  6. Review articles

    1. Quantitative rotating frame relaxometry methods in MRI

      Irtiza Ali Gilani and Raimo Sepponen

      Article first published online: 21 APR 2016 | DOI: 10.1002/nbm.3518

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      Contemporary MRI methods that have been employed to probe the biophysical mechanisms affecting the R1ρ and R2ρ relaxation rates of human tissue are thoroughly reviewed in this article. Rotating frame relaxation rates R1ρ and R2ρ can provide a non-invasive measure of the iron content and neuronal loss in diseases, such as Alzheimer's and Parkinson's disease. Spin-locking established by normal and adiabatic radiofrequency irradiation schemes are compared. Different acquisition strategies for accurate and precise quantitative imaging at high magnetic fields are reviewed.

  7. Research articles

    1. CEST-MRI detects metabolite levels altered by breast cancer cell aggressiveness and chemotherapy response

      Kannie W. Y. Chan, Lu Jiang, Menglin Cheng, Jannie P. Wijnen, Guanshu Liu, Peng Huang, Peter C. M. van Zijl, Michael T. McMahon and Kristine Glunde

      Article first published online: 21 APR 2016 | DOI: 10.1002/nbm.3526

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      Chemical exchange saturation transfer (CEST) was applied to detect 15 common cellular metabolites in a panel of differentially aggressive human breast cancer cell lines. The highest CEST contrast was generated by creatine, myo-inositol, glutamate, and glycerophosphocholine, whose cellular concentrations decreased with breast cancer aggressiveness. These decreased metabolite concentrations resulted in turn in a decreased CEST profile with increasing breast cancer aggressiveness in water-soluble extracts of breast cell lines. Treatment of both breast cancer cell lines with the chemotherapy drug doxorubicin resulted in increased metabolic CEST profiles, which correlated with significant increases in creatine, phosphocreatine, and glycerophosphocholine.

    2. Influence of regional cerebral blood volume on voxel-based morphometry

      Lei Zheng, Dirk Cleppien, Natalia Gass, Claudia Falfan-Melgoza, Barbara Vollmayr, Jürgen Hesser, Wolfgang Weber-Fahr and Alexander Sartorius

      Article first published online: 13 APR 2016 | DOI: 10.1002/nbm.3519

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      The result of voxel-based morphometry (VBM) might be sensitive to local physiological parameters, such as regional cerebral blood volume (rCBV) changes. Analyses in a study with the congenital learned helplessness (cLH) model were performed for long-term findings by statistical parametric mapping (SPM) and biological parametric mapping (BPM). Co-occurrence of differences in gray matter (GM) volume and rCBV was found, while there was no evidence of significant interaction between both.

  8. Special issue research articles

    1. Investigating lipids as a source of chemical exchange-induced MRI frequency shifts

      K. Shmueli, S. J. Dodd, P. van Gelderen and J. H. Duyn

      Article first published online: 13 APR 2016 | DOI: 10.1002/nbm.3525

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      We measured exchange-induced frequency shifts (fe) in a model of cell membranes consisting of multilamellar vesicles of cerebrosides and phospholipids. Using chemical shift imaging, with dioxane as an internal reference to remove susceptibility-induced frequency shifts, we found significant increases in fe with increasing lipid concentration: 0.044 ± 0.008 ppb/mM (r2 = 0.877, p < 0.01). We also measured and corrected for the water–dioxane frequency shift which was –0.021 ± 0.002 ppb/mM dioxane in agreement with previous measurements at low dioxane concentrations.

  9. Research articles

    1. Methodological and physiological test–retest reliability of 13C-MRS glycogen measurements in liver and in skeletal muscle of patients with type 1 diabetes and matched healthy controls

      Tania Buehler, Lia Bally, Ayse Sila Dokumaci, Christoph Stettler and Chris Boesch

      Article first published online: 13 APR 2016 | DOI: 10.1002/nbm.3531

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      Determination of glycogen levels by means of 13C-MR spectroscopy is attractive yet very time consuming, such that interventional studies with a lengthy MRS–intervention–MRS sequence are often not feasible or could introduce systematic bias due to fatigue, hormonal changes or other variations. This study found in healthy volunteers and type 1 diabetes patients that physiological standardization can lead to sufficiently reproducible glycogen levels at baseline and that pre- and post-intervention MRS could be determined on separate days without increasing the methodological variations further.

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      Optimization of 4D vessel-selective arterial spin labeling angiography using balanced steady-state free precession and vessel-encoding

      Thomas W. Okell, Peter Schmitt, Xiaoming Bi, Michael A. Chappell, Rob H. N. Tijssen, Fintan Sheerin, Karla L. Miller and Peter Jezzard

      Article first published online: 13 APR 2016 | DOI: 10.1002/nbm.3515

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      A time-resolved balanced steady-state free precession readout was optimized for arterial spin labeling dynamic angiography, compared with spoiled gradient echo, and combined with a vessel-encoded preparation to allow the generation of 4D (dynamic 3D) non-contrast vessel-selective angiograms with high spatial and temporal resolution. Signal-to-noise ratio efficiency and vessel-selectivity were shown to be high. A dynamic 2D protocol took only 1.5 min. Potential applications include the assessment of collateral blood flow and evaluation of the arterial supply to lesions.

    3. Diffusional kurtosis MRI of the lower leg: changes caused by passive muscle elongation and shortening

      Lukas Filli, David Kenkel, Moritz C. Wurnig and Andreas Boss

      Article first published online: 8 APR 2016 | DOI: 10.1002/nbm.3529

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      Diffusional kurtosis MRI (DKI) has recently gained interest for the detailed characterization of tissue microstructure. We demonstrate that diffusional kurtosis (K) in the lower leg muscles is significantly influenced by the joint ankle position. This extends our knowledge about the physiological microstructural behavior of skeletal muscle, and may have implications for future research on muscle pathologies.

    4. MRSI-based molecular imaging of therapy response to temozolomide in preclinical glioblastoma using source analysis

      T. Delgado-Goñi, S. Ortega-Martorell, M. Ciezka, I. Olier, A. P. Candiota, M. Julià-Sapé, F. Fernández, M. Pumarola, P. J. Lisboa and C. Arús

      Article first published online: 8 APR 2016 | DOI: 10.1002/nbm.3521

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      The methodology described in this work is able to characterize the response to TMZ in preclinical GB both at a defined time point and in real time, throughout the therapy protocol. The response patterns detected correlate well with the histopathological analysis of control and treated tumors at each stage. This strategy has translational potential for monitoring patient response to treatment.

    5. Hierarchical non-negative matrix factorization applied to three-dimensional 3 T MRSI data for automatic tissue characterization of the prostate

      Teresa Laudadio, Anca R. Croitor Sava, Diana M. Sima, Alan J. Wright, Arend Heerschap, Nicola Mastronardi and Sabine Van Huffel

      Article first published online: 8 APR 2016 | DOI: 10.1002/nbm.3527

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      In this study non-negative matrix factorization (NMF) is hierarchically applied to simulated and to in vivo MRSI data of the prostate to extract characteristic patterns for tumour and benign tissue and to visualize their spatial distribution. The hierarchical scheme provides higher quality tissue patterns than obtained by performing one NMF level. In the image TP (TM) and BP (BM) respectively stand for tumour and benign patterns (models), and MAT for the most aggressive tumour spectrum in the dataset

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    6. In vivo MR guided boiling histotripsy in a mouse tumor model evaluated by MRI and histopathology

      Martijn Hoogenboom, Dylan Eikelenboom, Martijn H. den Brok, Andor Veltien, Melissa Wassink, Pieter Wesseling, Erik Dumont, Jurgen J. Fütterer, Gosse J. Adema and Arend Heerschap

      Article first published online: 7 APR 2016 | DOI: 10.1002/nbm.3520

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      An in vivo MR guided boiling histotripsy (BH) set-up is developed for the treatment of subcutaneous mouse tumors. With BH, the tissue is fragmentized into submicron fragments, without significant hemorrhages and with a sharp transition zone (<200 µm) between disintegrated and vital tissue. Both one hour and four days post treatment, among T1w, T2w, PDw and DCE imaging, T2w imaging was found to be the best method for treatment planning and evaluation.

    7. 39K and 23Na relaxation times and MRI of rat head at 21.1 T

      Armin M. Nagel, Reiner Umathum, Manuela B. Rösler, Mark E. Ladd, Ilya Litvak, Peter L. Gor'kov, William W. Brey and Victor D. Schepkin

      Article first published online: 7 APR 2016 | DOI: 10.1002/nbm.3528

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      39K and 23Na relaxation times show a distinct increase with magnetic field strength, which is beneficial for MRI at ultrahigh magnetic field strengths (e.g. 21.1 T). This increase is more pronounced for 39K MRI. 39K MRI largely benefits from ultrahigh magnetic fields, and the acquired in vivo 39K MR images of healthy rat brain show markedly improved resolution and image quality compared with previous work performed at 9.4 T.

    8. UTE–ΔR2–ΔR2* combined MR whole-brain angiogram using dual-contrast superparamagnetic iron oxide nanoparticles

      H. S. Jung, S. H. Jin, J. H. Cho, S. H. Han, D. K. Lee and H. Cho

      Article first published online: 7 APR 2016 | DOI: 10.1002/nbm.3514

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      Through Monte Carlo (MC) simulation and MR angiography (MRA) experiments in normal and tumor-bearing animals with intravascular superparamagnetic iron oxide nanoparticles (SPION), we show that ultrashort TE (UTE) MRA acquires well-defined vascularization on the brain surface, minimizing air–tissue artifacts, and the multiplied ΔR2 and ΔR2* MRAs simultaneously improve the sensitivity to intracortical penetrating vessels and reduce vessel size overestimation. Consequently, UTE–ΔR2–ΔR2* combined MRA complements the shortcomings of individual angiograms and provides a strategy to synergistically merge longitudinal and transverse relaxation effects to generate a more robust in vivo whole-brain micro-MRA.

  10. Special issue review articles

    1. Mechanisms of T2* anisotropy and gradient echo myelin water imaging

      Jongho Lee, Yoonho Nam, Joon Yul Choi, Eung Yeop Kim, Se-Hong Oh and Dong-Hyun Kim

      Article first published online: 7 APR 2016 | DOI: 10.1002/nbm.3513

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      A white matter voxel demonstrates T2* anisotropy that originates from isotropic and anisotropic magnetic susceptibility and multi-compartmental microstructure induced frequency shifts. These mechanisms result in multi-exponential magnitude decay and nonlinear phase evolution. Using the complex signal, myelin water fraction can be estimated, producing gradient echo myelin water imaging.

  11. Research articles

    1. Influence of fat–water separation and spatial resolution on automated volumetric MRI measurements of fibroglandular breast tissue

      Georg J. Wengert, Katja Pinker-Domenig, Thomas H. Helbich, Wolf-Dieter Vogl, Paola Clauser, Hubert Bickel, Maria-Adele Marino, Heinrich F. Magometschnigg and Pascal A. Baltzer

      Article first published online: 7 APR 2016 | DOI: 10.1002/nbm.3516

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      Automated quantitative MRI measurement approaches of breast fibroglandular tissue (FGT), using different T1- and T2-weighted sequences, as well as fat–water separation techniques, are introduced. This article investigates the influence of fat–water separation and spatial resolution in MRI on the results of automated quantitative measurements of FGT. Dixon fat–water separation techniques showed superior repeatability of FGT measurements compared with conventional sequences. A standard dynamic protocol using Dixon fat saturation is best suited for combined diagnostic purposes and prognostic measurements of FGT.

    2. Whole-body radiofrequency coil for 31P MRSI at 7 T

      J. Löring, W. J. M. van der Kemp, S. Almujayyaz, J. W. M. van Oorschot, P. R. Luijten and D. W. J. Klomp

      Article first published online: 1 APR 2016 | DOI: 10.1002/nbm.3517

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      31P MRSI can be obtained throughout the human body with an integrated body radiofrequency (RF) coil at 7 T that includes pick-up coils for fast power calibration. High B1 efficiency can be appreciated by the strong T1 weighting and the relatively high bandwidth observed in the spectra. The similarity of the spectra over the liver shows the uniformity of the B1 fields obtained.

    3. Quantitative analysis of the reconstruction errors of the currently popular algorithm of magnetic resonance electrical property tomography at the interfaces of adjacent tissues

      Song Duan, Chao Xu, Guanhua Deng, Jiajia Wang, Feng Liu and Sherman Xuegang Xin

      Article first published online: 1 APR 2016 | DOI: 10.1002/nbm.3522

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      Magnetic resonance electrical property tomography (MREPT) is a recently developed imaging approach, regarded as a potential tool for the early detection of tumors. Reducing reconstruction errors (REs) is important to improve the MREPT technique. This article analyzed quantitatively REs using a currently popular algorithm. Various REs were observed along different tissue interfaces shown in the figure. The mean relative REs ranged from 0.3986 to 36.11 for conductivity and 0.2218 to 11.96 for relative permittivity with respect to different interfaces.

  12. Special issue review articles

    1. Susceptibility-based time-resolved whole-organ and regional tissue oximetry

      Felix W. Wehrli, Audrey P. Fan, Zachary B. Rodgers, Erin K. Englund and Michael C. Langham

      Article first published online: 26 FEB 2016 | DOI: 10.1002/nbm.3495

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      Quantification of reactive hyperemia with dynamic oximetry showing cross-sectional phase difference image of the thigh, 10 cm below the inferior boundary of the pressure cuff along with post-ischemia femoral vein SvO2 time course, and series of zoomed phase images showing relative phase of venous blood during period indicated. Darker blue represents lower saturation levels. Parameterization of time-course data yields quantitative metrics: washout time, upslope and overshoot.

  13. Special issue research articles

    1. Reproducibility of R2* and quantitative susceptibility mapping (QSM) reconstruction methods in the basal ganglia of healthy subjects

      M. D. Santin, M. Didier, R. Valabrègue, L. Yahia Cherif, D. García-Lorenzo, P. Loureiro de Sousa, E. Bardinet and S. Lehéricy

      Article first published online: 23 FEB 2016 | DOI: 10.1002/nbm.3491

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      The registration of four sessions of three-dimensional gradient echo complex images in a cohort of healthy subjects allowed the quantification of the reproducibility of quantitative susceptibility mapping (QSM) methods versus the reproducibility of more conventional R2* mapping. The sensitivity to changes in the QSM technique was shown to reach a level of 1.5% in the basal ganglia.

    2. Joint 2D and 3D phase processing for quantitative susceptibility mapping: application to 2D echo-planar imaging

      Hongjiang Wei, Yuyao Zhang, Eric Gibbs, Nan-Kuei Chen, Nian Wang and Chunlei Liu

      Article first published online: 17 FEB 2016 | DOI: 10.1002/nbm.3501

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      Current two-dimensional (2D) echo-planar imaging (EPI)-based quantitative susceptibility mapping (QSM) uses three-dimensional (3D) phase unwrapping followed by 3D background phase removal, and leaves phase inconsistencies across slices. Here, we report a new data processing procedure that integrates 2D and 3D phase processing to reduce phase inconsistencies between slices. Experimental results show that the new 2D EPI-based QSM method can produce quantitative susceptibility measures that are comparable with those of time-consuming 3D gradient-echo (GRE)-based QSM.

    3. Quantitative susceptibility mapping at 3 T: comparison of acquisition methodologies

      M. Louis Lauzon, Cheryl R. McCreary, D. Adam McLean, Marina Salluzzi and Richard Frayne

      Article first published online: 17 FEB 2016 | DOI: 10.1002/nbm.3492

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      We compared deep grey matter susceptibility (χ) values in healthy adults acquired from various quantitative susceptibility mapping (QSM) sequences at 3 T using unipolar or bipolar readout gradients, accelerated imaging or not (R2 or R1), with/without gradient-warp correction (GW). Using a linear mixed effects model, only GW was found to alter the χ estimate, but its overall effect was small (~5%).

  14. Special issue review articles

    1. New insights into rotating frame relaxation at high field

      John T. Spear and John C. Gore

      Article first published online: 11 FEB 2016 | DOI: 10.1002/nbm.3490

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      Spin-locking at high static fields provides the ability to examine relatively slow molecular motions, specifically diffusion and chemical exchange, which are shown to dominate relaxation in the rotating frame. R dispersions provide insight into these relaxation mechanisms, and these are shown to be independent effects through finite difference simulations and experiments examining the impact of blood oxygenation. These mechanisms can be exploited further to potentially estimate solute concentrations in mixtures or to infer geometric distributions of inhomogeneities.

  15. Special issue research articles

    1. Regionally progressive accumulation of iron in Parkinson's disease as measured by quantitative susceptibility mapping

      Xiaojun Guan, Min Xuan, Quanquan Gu, Peiyu Huang, Chunlei Liu, Nian Wang, Xiaojun Xu, Wei Luo and Minming Zhang

      Article first published online: 8 FEB 2016 | DOI: 10.1002/nbm.3489

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      Quantitative susceptibility mapping was used to confirm a regionally progressive pattern of iron accumulation in patients with Parkinson's disease (PD) at different stages, which indicates that iron deposition in the substantia nigra pars compacta (SNc) is affected exclusively in the early PD (EPD) patients, while the substantia nigra pars reticulata (SNr), red nucleus (RN) and globus pallidus internal (GPi) as well as globus pallidus external (GPe) become involved in the late PD (LPD) patients.

  16. Special issue review articles

    1. Rapid brain MRI acquisition techniques at ultra-high fields

      Kawin Setsompop, David A. Feinberg and Jonathan R. Polimeni

      Article first published online: 2 FEB 2016 | DOI: 10.1002/nbm.3478

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      Recent development trends in moving away from 2D imaging to simultaneous multislice (SMS) and 3D imaging have provided dramatic improvements in acquisition speed and SNR efficiency for high-resolution imaging at ultra-high field. SMS and 3D imaging can make better use of coil sensitivity information for parallel imaging acquisitions through controlled aliasing in multiple spatial directions. This has enabled unprecedented acceleration factors of an order of magnitude or higher, with low artifact levels and high SNR.

    2. In vivo diffusion MRS investigation of non-water molecules in biological tissues

      Peng Cao and Ed X. Wu

      Article first published online: 21 JAN 2016 | DOI: 10.1002/nbm.3481

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      In this review, recent diffusion MRS studies of biologically relevant non-water molecules under normal and diseased conditions will be presented. Technique considerations for diffusion MRS experiments will be discussed. With advances in MRI hardware and diffusion methodology, diffusion MRS of non-water molecules is expected to provide increasingly valuable and biologically specific information on tissue microstructures and physiology, complementing the traditional diffusion MR of small and ubiquitous water molecules.

    3. Diffusion MRI in early cancer therapeutic response assessment

      C. J. Galbán, B. A. Hoff, T. L. Chenevert and B. D. Ross

      Article first published online: 15 JAN 2016 | DOI: 10.1002/nbm.3458

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      Diffusion-weighted MRI (DW-MRI) is sensitive to cellular changes and has been evaluated extensively as a quantitative and early imaging biomarker of the therapeutic response. DW-MR can be applied to many different solid tumors to detect changes in cellularity as measured by an early increase in the apparent diffusion coefficient (ADC) of water molecules within the lesion. An overview of DW-MRI acquisition protocols, quantitative image analysis approaches and applications implementing DW-MRI for the early prediction of cancer treatment response is presented.

    4. Diffusion lung imaging with hyperpolarized gas MRI

      Dmitriy A. Yablonskiy, Alexander L. Sukstanskii and James D. Quirk

      Article first published online: 16 DEC 2015 | DOI: 10.1002/nbm.3448

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      Diffusion MRI with hyperpolarized gases provides quantitative information on lung microstructure at the alveolar level and makes it possible to measure the same morphometric parameters (mean linear intercept, surface-to-volume ratio, number of alveoli per unit volume) as have been traditionally obtained by means of invasive stereology.

  17. Special issue research articles

    1. Proton observed phosphorus editing (POPE) for in vivo detection of phospholipid metabolites

      Jannie P. Wijnen, Dennis W. J. Klomp, Christine I. H. C. Nabuurs, Robin A. de Graaf, Irene M. L. van Kalleveen, Wybe J. M. van der Kemp, Peter R. Luijten, Mark C. Kruit, Andrew Webb, Hermien E. Kan and Vincent O. Boer

      Article first published online: 25 NOV 2015 | DOI: 10.1002/nbm.3440

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      We demonstrate the enhanced sensitivity of proton observed phosphorus editing (POPE) over direct 31P MRS with Ernst angle excitation for 1H–31P coupled metabolites in the human brain at 7 T.

  18. Special issue review articles

    1. Diffusion tensor imaging in abdominal organs

      Rotem Shlomo Lanzman and Hans-Jörg Wittsack

      Article first published online: 11 NOV 2015 | DOI: 10.1002/nbm.3434

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      Diffusion tensor imaging of abdominal organs adds additional diagnostic information about the microstructure of human tissues. Besides the technical requirements for DTI in abdominal organs, recent studies of major organs such as kidney, liver, prostate and pelvic floor are presented and discussed.

    2. You have full text access to this OnlineOpen article
      Diffusion MRI in the heart

      Choukri Mekkaoui, Timothy G. Reese, Marcel P. Jackowski, Himanshu Bhat and David E. Sosnovik

      Article first published online: 20 OCT 2015 | DOI: 10.1002/nbm.3426

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      Diffusion MRI provides unique information on the integrity of the myocardium without the need for exogenous contrast agents. However, diffusion MRI in the heart has proven technically challenging. In this review, we describe approaches that have been developed to overcome these challenges, and briefly examine the application of diffusion MRI in ischemic heart disease. The use of diffusion MRI as a clinical tool may lead to new and complementary approaches to diagnose and treat patients with heart disease.

  19. Special issue research articles

    1. Dipole antennas for ultrahigh-field body imaging: a comparison with loop coils

      A. J. E. Raaijmakers, P. R. Luijten and C. A. T. van den Berg

      Article first published online: 17 AUG 2015 | DOI: 10.1002/nbm.3356

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      This article provides electromagnetic insight into the operating principles of dipole antennas by numerical simulations. It focuses on a comparison study of dipole antennas and loop coils at the frequencies of 128, 298 and 400 MHz. When the optimal element is chosen for each depth, loop coils have higher B1+ efficiency for shallow depths, whereas dipole antennas have higher B1+ efficiency for large depths. Loop coils demonstrate a better B1+/√SARmax ratio, but not in an array setup with overlapping elements.

    2. Concurrent recording of RF pulses and gradient fields – comprehensive field monitoring for MRI

      David O. Brunner, Benjamin E. Dietrich, Mustafa Çavuşoğlu, Bertram J. Wilm, Thomas Schmid, Simon Gross, Christoph Barmet and Klaas P. Pruessmann

      Article first published online: 13 AUG 2015 | DOI: 10.1002/nbm.3359

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      By using NMR field probes in conjunction with broadband RF receivers, a stand-alone monitoring unit measuring RF pulses and gradient waveforms concurrently and with common timing was built. The unit can capture the field dynamics of multi-channel RF transmission systems without the need for dedicated RF pickups, and delivers a comprehensive sequence depiction as it is executed by the scanner. These abilities are exemplified by monitoring typically challenging applications such bSSFP, UTE and spatially selective parallel transmission pulses at 7 T.

  20. Special issue review articles

    1. Diffusion imaging of the vertebral bone marrow

      Olaf Dietrich, Tobias Geith, Maximilian F. Reiser and Andrea Baur-Melnyk

      Article first published online: 26 JUN 2015 | DOI: 10.1002/nbm.3333

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      Diffusion-weighted MRI (DWI) of the vertebral bone marrow is a clinically important tool for the characterization of bone-marrow pathologies and, in particular, for the differentiation of benign and malignant vertebral compression fractures. DWI of the vertebral bone marrow is, however, complicated by some unique MR and tissue properties of vertebral bone marrow. This review summarizes data from numerous studies in which diffusion measurements of normal vertebral bone marrow and of different vertebral bone-marrow lesions were performed.

  21. Review articles

    1. You have full text access to this OnlineOpen article
      Parallel transmission for ultrahigh-field imaging

      Francesco Padormo, Arian Beqiri, Joseph V. Hajnal and Shaihan J. Malik

      Article first published online: 19 MAY 2015 | DOI: 10.1002/nbm.3313

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      Ultrahigh-field MRI provides a powerful new investigational device for in vivo imaging, but is hindered by non-uniform and variable radiofrequency fields. Parallel transmission (PTx) promises to address these issues by providing more control over the fields. In this article, we review methods for exploiting the new degrees of freedom provided by PTx to improve image quality and to reduce the specific absorption rate (SAR).

  22. Special issue review articles

    1. The technological future of 7 T MRI hardware

      A. G. Webb and P. F. Van de Moortele

      Article first published online: 14 MAY 2015 | DOI: 10.1002/nbm.3315

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      In this article we present some projections for future hardware developments on human 7 T MRI scanners. Areas covered include magnet design, magnetic field gradients, RF coils, dynamic shimming, SAR estimation, and patient monitoring.

  23. Special issue research articles

    1. A simple approach to evaluate the kinetic rate constant for ATP synthesis in resting human skeletal muscle at 7 T

      Jimin Ren, A. Dean Sherry and Craig R. Malloy

      Article first published online: 6 MAY 2015 | DOI: 10.1002/nbm.3310

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      Extracting the ATP synthesis rate constant (kPi[RIGHTWARDS ARROW]γATP) from 31P inversion transfer measurements is generally complicated by the tangle of multiple spin relaxation and exchange parameters in the magnetization equations describing the exchange system. This problem can be avoided by using a simple alternative approach based on the Bloch–McConnell equation for inorganic phosphate Pi, which allows the evaluation of kPi[RIGHTWARDS ARROW]γATP by a linear plot of Pi magnetization rate (m˙Pi) against the magnetization difference between Pi and γ-ATP (mPi − mγATP) .

    2. You have full text access to this OnlineOpen article
      Assessment of blood flow velocity and pulsatility in cerebral perforating arteries with 7-T quantitative flow MRI

      W. H. Bouvy, L. J. Geurts, H. J. Kuijf, P. R. Luijten, L. J. Kappelle, G. J. Biessels and J. J. M. Zwanenburg

      Article first published online: 27 APR 2015 | DOI: 10.1002/nbm.3306

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      A two-dimensional, single-slice, quantitative flow (Qflow) sequence on a 7-T system yielded the first non-invasive in vivo measurements of blood flow velocity and pulsatility in cerebral perforating arteries in the basal ganglia (BG) and semioval centre (CSO), with the middle cerebral artery as reference. The precision of the velocity measurements in individual vessels and the pulsatility index per anatomical region was determined using Bland–Altman analysis. This sequence allows the study of the haemodynamics of cerebral perforating arteries and their association with, for example, vascular lesions.

    3. Safety testing and operational procedures for self-developed radiofrequency coils

      Jens Hoffmann, Anke Henning, Ioannis A. Giapitzakis, Klaus Scheffler, G. Shajan, Rolf Pohmann and Nikolai I. Avdievich

      Article first published online: 6 APR 2015 | DOI: 10.1002/nbm.3290

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      Herein, a comprehensive guideline on electrical and mechanical safety tests, specific absorption rate (SAR) simulation, risk analysis and operational procedures for self-developed RF coils is described that helps to recognize and eliminate safety concerns during RF coil design and operation. Although the procedure is generally applicable to all field strengths, specific requirements with regard to SAR simulation and verification, as well as electrical safety and performance, at ultrahigh-field are considered.

  24. Special issue review articles

    1. Recent applications of UHF-MRI in the study of human brain function and structure: a review

      Wietske van der Zwaag, Andreas Schäfer, José P. Marques, Robert Turner and Robert Trampel

      Article first published online: 12 MAR 2015 | DOI: 10.1002/nbm.3275

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      MRI at ultra-high field strength of 7 T and greater has made tremendous progress over the last decade and a half. This review discusses the rapidly expanding literature on UHF applications of BOLD fMRI and structural imaging in the brain, including relaxation-time-weighted imaging, phase imaging, and QSM; angiography and diffusion- and MT-weighted imaging.

    2. Clinical applications at ultrahigh field (7  T). Where does it make the difference?

      Siegfried Trattnig, Wolfgang Bogner, Stephan Gruber, Pavol Szomolanyi, Vladimir Juras, Simon Robinson, Štefan Zbýň and Stefan Haneder

      Article first published online: 12 MAR 2015 | DOI: 10.1002/nbm.3272

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      Although it will probably take some years before full whole-body investigations can be performed routinely with high quality at 7 T, many morphological applications, as well as metabolic and functional MRI applications, in neuroimaging, musculoskeletal and breast imaging have already been shown to be superior compared with the benchmark 3 T, which will further enhance the move to 7 T. The rapid increase in operating 7-T systems indicates the growing interest in ultrahigh-field MRI because of the improved clinical results with regard to morphological detail, as well as functional and metabolic imaging capabilities.

    3. W(h)ither human cardiac and body magnetic resonance at ultrahigh fields? technical advances, practical considerations, applications, and clinical opportunities

      Thoralf Niendorf, Katharina Paul, Celal Oezerdem, Andreas Graessl, Sabrina Klix, Till Huelnhagen, Fabian Hezel, Jan Rieger, Helmar Waiczies, Jens Frahm, Armin M. Nagel, Eva Oberacker and Lukas Winter

      Article first published online: 23 FEB 2015 | DOI: 10.1002/nbm.3268

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      This work documents and reviews advances and progress in cardiac and body MR technology at ultrahigh fields and its application in forefront research and in early clinical applications. The achievements of ultrahigh field cardiac and body MR are shown to be a powerful motivator and enabler, since the extra speed, signal and imaging capabilities may be invested to overcome the fundamental constraints that continue to hamper traditional cardiac and body MR applications at lower magnetic field strengths.

  25. Special issue research articles

    1. Cortical phase changes measured using 7-T MRI in subjects with subjective cognitive impairment, and their association with cognitive function

      Sanneke van Rooden, Mathijs Buijs, Marjolein E. van Vliet, Maarten J. Versluis, Andrew G. Webb, Ania M. Oleksik, Lotte van de Wiel, Huub A. M. Middelkoop, Gerard Jan Blauw, Annelies W. E. Weverling-Rynsburger, Jeroen D. C. Goos, Wiesje M. van der Flier, Ted Koene, Philip Scheltens, Frederik Barkhof, Ondine van de Rest, P. Eline Slagboom, Mark A. van Buchem and Jeroen van der Grond

      Article first published online: 19 DEC 2014 | DOI: 10.1002/nbm.3248

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      In subjects with subjective cognitive impairment (SCI), Alzheimer's disease-like changes may occur in the brain. We investigated whether cortical phase shifts at 7 T in SCI can be detected, implicating the deposition of amyloid-beta (Aβ) plaques and associated iron, and which cognitive domains are associated with cortical phase shifts in SCI. In SCI, an increased cortical phase shift at high field is associated with a poorer memory performance, although no increased phase shift could be determined in subjects with SCI compared with controls.

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