F W Wehrli

Summary

Affiliation: University of Pennsylvania
Country: USA

Publications

  1. ncbi request reprint New architectural parameters derived from micro-MRI for the prediction of trabecular bone strength
    F W Wehrli
    Department of Radiology, University of Pennsylvania Medical Center, Philadelphia 19104, USA
    Technol Health Care 6:307-20. 1998
  2. ncbi request reprint Assessment of axonal fiber tract architecture in excised rat spinal cord by localized NMR q-space imaging: simulations and experimental studies
    Chih Liang Chin
    University of Pennsylvania Medical Center, Department of Radiology, Philadelphia, Pennsylvania 19104, USA
    Magn Reson Med 52:733-40. 2004
  3. ncbi request reprint Role of magnetic resonance for assessing structure and function of trabecular bone
    Felix W Wehrli
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, 1 Founders Pavilion, 3400 Spruce Street, Philadelphia, PA 19104, USA
    Top Magn Reson Imaging 13:335-55. 2002
  4. ncbi request reprint Cross-sectional study of osteopenia with quantitative MR imaging and bone densitometry
    F W Wehrli
    Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce St, 1 Founders, Philadelphia, PA 19104, USA
    Radiology 217:527-38. 2000
  5. ncbi request reprint Digital topological analysis of in vivo magnetic resonance microimages of trabecular bone reveals structural implications of osteoporosis
    F W Wehrli
    Department of Radiology, University of Pennsylvania Medical Center, Philadelphia 19104, USA
    J Bone Miner Res 16:1520-31. 2001
  6. ncbi request reprint Measurement of phosphorus content in normal and osteomalacic rabbit bone by solid-state 3D radial imaging
    S Anumula
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, PA 19104, USA
    Magn Reson Med 56:946-52. 2006
  7. ncbi request reprint Trabecular bone volume fraction mapping by low-resolution MRI
    M A Fernández-Seara
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, PA 19104, USA
    Magn Reson Med 46:103-13. 2001
  8. pmc Multi-modality study of the compositional and mechanical implications of hypomineralization in a rabbit model of osteomalacia
    S Anumula
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Health System, Philadelphia, PA 19104, USA
    Bone 42:405-13. 2008
  9. ncbi request reprint In vivo MR micro imaging with conventional radiofrequency coils cooled to 77 degrees K
    A C Wright
    Department of Radiology, Hosptial of the University of Pennsylvania, Philadelphia 19104, USA
    Magn Reson Med 43:163-9. 2000
  10. pmc Ultra-short echo-time MRI detects changes in bone mineralization and water content in OVX rat bone in response to alendronate treatment
    S Anumula
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Health System, 3400 Spruce Street, Philadelphia, PA 19104, USA
    Bone 46:1391-9. 2010

Collaborators

Detail Information

Publications83

  1. ncbi request reprint New architectural parameters derived from micro-MRI for the prediction of trabecular bone strength
    F W Wehrli
    Department of Radiology, University of Pennsylvania Medical Center, Philadelphia 19104, USA
    Technol Health Care 6:307-20. 1998
    ..and SNR approximately 10. Finally, data are presented highlighting the potential of these methods for predicting the bone's elastic modulus in vitro and fracture risk in vivo...
  2. ncbi request reprint Assessment of axonal fiber tract architecture in excised rat spinal cord by localized NMR q-space imaging: simulations and experimental studies
    Chih Liang Chin
    University of Pennsylvania Medical Center, Department of Radiology, Philadelphia, Pennsylvania 19104, USA
    Magn Reson Med 52:733-40. 2004
    ..The data suggest the NMR q-space approach has potential for nondestructive analysis of the axonal architecture in the mammalian spinal cord...
  3. ncbi request reprint Role of magnetic resonance for assessing structure and function of trabecular bone
    Felix W Wehrli
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, 1 Founders Pavilion, 3400 Spruce Street, Philadelphia, PA 19104, USA
    Top Magn Reson Imaging 13:335-55. 2002
    ..The method currently is confined to peripheral skeletal sites, and its extension to typical fracture sites such as the proximal femur hinges on further advances in detection sensitivity...
  4. ncbi request reprint Cross-sectional study of osteopenia with quantitative MR imaging and bone densitometry
    F W Wehrli
    Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce St, 1 Founders, Philadelphia, PA 19104, USA
    Radiology 217:527-38. 2000
    ..To evaluation the cancellous bone-induced intravoxel spin dephasing rate (R2') and its relationship to bone mineral density and marrow fat and to examine these parameters as predictors of vertebral fracture status...
  5. ncbi request reprint Digital topological analysis of in vivo magnetic resonance microimages of trabecular bone reveals structural implications of osteoporosis
    F W Wehrli
    Department of Radiology, University of Pennsylvania Medical Center, Philadelphia 19104, USA
    J Bone Miner Res 16:1520-31. 2001
    ....
  6. ncbi request reprint Measurement of phosphorus content in normal and osteomalacic rabbit bone by solid-state 3D radial imaging
    S Anumula
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, PA 19104, USA
    Magn Reson Med 56:946-52. 2006
    ..2 +/- 3.5 vs. 54.1 +/- 2.7 s, P = 0.004), which suggests that relaxation occurs via a dipole-dipole (DD) mechanism involving exchangeable water protons, which are more prevalent in bone from osteomalacic animals...
  7. ncbi request reprint Trabecular bone volume fraction mapping by low-resolution MRI
    M A Fernández-Seara
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, PA 19104, USA
    Magn Reson Med 46:103-13. 2001
    ..0001). The method may fail in large imaging objects such as the human trunk at high magnetic field where standing wave and RF penetration effects cause intensity variations that cannot be corrected. Magn Reson Med 46:103-113, 2001...
  8. pmc Multi-modality study of the compositional and mechanical implications of hypomineralization in a rabbit model of osteomalacia
    S Anumula
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Health System, Philadelphia, PA 19104, USA
    Bone 42:405-13. 2008
    ..47, p=0.001) as well as with ultimate strength (r(2)=0.54, p=0.0004). The results show that the methods presented have potential for in situ assessment of mineralization and water, both critical to the bone's mechanical behavior...
  9. ncbi request reprint In vivo MR micro imaging with conventional radiofrequency coils cooled to 77 degrees K
    A C Wright
    Department of Radiology, Hosptial of the University of Pennsylvania, Philadelphia 19104, USA
    Magn Reson Med 43:163-9. 2000
    ..The performance of the coil is illustrated with images from the human finger and rabbit eye and potential applications are discussed...
  10. pmc Ultra-short echo-time MRI detects changes in bone mineralization and water content in OVX rat bone in response to alendronate treatment
    S Anumula
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Health System, 3400 Spruce Street, Philadelphia, PA 19104, USA
    Bone 46:1391-9. 2010
    ....
  11. pmc Method for cortical bone structural analysis from magnetic resonance images
    Bryon R Gomberg
    Department of Radiology, Laboratory for Structural NMR Imaging, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, Pennsylvania 19104, USA
    Acad Radiol 12:1320-32. 2005
    ..The aim of this study is to develop MR acquisition and analysis methods optimized for the detection of cortical boundaries in such complex geometries as the femoral neck...
  12. doi request reprint 3D fast spin echo with out-of-slab cancellation: a technique for high-resolution structural imaging of trabecular bone at 7 Tesla
    Jeremy F Magland
    Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104, USA
    Magn Reson Med 63:719-27. 2010
    ....
  13. pmc Spin-echo micro-MRI of trabecular bone using improved 3D fast large-angle spin-echo (FLASE)
    J F Magland
    Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104, USA
    Magn Reson Med 61:1114-21. 2009
    ....
  14. ncbi request reprint Implications of pulse sequence in structural imaging of trabecular bone
    Aranee Techawiboonwong
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104, USA
    J Magn Reson Imaging 22:647-55. 2005
    ....
  15. pmc Retrospective 3D registration of trabecular bone MR images for longitudinal studies
    Jeremy F Magland
    Department of Radiology, University of Pennsylvania Health System, Philadelphia, Pennsylvania, USA
    J Magn Reson Imaging 29:118-26. 2009
    ..To evaluate an automatic 3D registration algorithm for serial high-resolution images of trabecular bone (TB) in studies designed to evaluate the response of the trabecular architecture to intervention or disease progression...
  16. ncbi request reprint Spatial autocorrelation and mean intercept length analysis of trabecular bone anisotropy applied to in vivo magnetic resonance imaging
    Michael J Wald
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104, USA
    Med Phys 34:1110-20. 2007
    ..There was good agreement between the two techniques as far as the eigenvectors of the fabric ellipsoids were concerned, which parallel the bone's macroscopic axis...
  17. ncbi request reprint A novel local thresholding algorithm for trabecular bone volume fraction mapping in the limited spatial resolution regime of in vivo MRI
    Branimir Vasilic
    Department of Radiology, The University of Pennsylvania Medical Center, 3400 Spruce Street, 1st Floor Founders, MRI Leaming Center, Philadelphia, PA 19104 USA
    IEEE Trans Med Imaging 24:1574-85. 2005
    ..Finally, we demonstrate that the LTA is superior in preserving connectivity by showing for 75 in vivo images that the genus of the trabecular bone surface is always higher than when processed with the HDA...
  18. pmc Construction and calibration of a 50 T/m z-gradient coil for quantitative diffusion microimaging
    A C Wright
    Laboratory for Structural NMR Imaging, Department of Radiology, 1 Silverstein, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, PA 19104, USA
    J Magn Reson 186:17-25. 2007
    ..5 microm diameter), which showed the expected diffraction peak. In addition, diffusion-weighted images of a fixed mouse spinal cord illustrated the capability of this coil for quantitative imaging of tissue microstructure...
  19. pmc Implications of resolution and noise for in vivo micro-MRI of trabecular bone
    Charles Q Li
    Department of Radiology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
    Med Phys 35:5584-94. 2008
    ....
  20. pmc Trabecular bone structure analysis in the limited spatial resolution regime of in vivo MRI
    Jeremy F Magland
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Health System, Philadelphia, PA 19104, USA
    Acad Radiol 15:1482-93. 2008
    ....
  21. ncbi request reprint Skeletal effects of short-term exposure to dexamethasone and response to risedronate treatment studied in vivo in rabbits by magnetic resonance micro-imaging and spectroscopy
    Masaya Takahashi
    Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, PA 19104, USA
    J Bone Miner Metab 24:467-75. 2006
    ..The data lend support to a protective effect of risedronate on trabecular architecture during GC exposure. The improvement in trabecular network parameters beyond baseline values further suggest a therapeutic effect of risedronate...
  22. ncbi request reprint Image metric-based correction (autofocusing) of motion artifacts in high-resolution trabecular bone imaging
    Wei Lin
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania, USA
    J Magn Reson Imaging 26:191-7. 2007
    ..To evaluate the performance of the autofocusing (AF) motion correction technique in high-resolution trabecular bone imaging where image signal-to noise ratio (SNR) is limited...
  23. ncbi request reprint Nuclear magnetic resonance studies of bone water
    Felix W Wehrli
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, PA 19104, USA
    Ann Biomed Eng 33:79-86. 2005
    ..Finally, whereas isotope exchange is not feasible in vivo, it is shown that bone water can be imaged by proton MRI...
  24. pmc Mineral volume and morphology in carotid plaque specimens using high-resolution MRI and CT
    Ronald L Wolf
    Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce St, Philadelphia, PA 19104, USA
    Arterioscler Thromb Vasc Biol 25:1729-35. 2005
    ..The purpose of this study was to assess the performance of high-resolution MRI in evaluation of the quantity and pattern of mineral deposition in carotid endarterectomy (CEA) specimens, with quantitative micro-CT as the gold standard...
  25. ncbi request reprint Structural and functional assessment of trabecular and cortical bone by micro magnetic resonance imaging
    Felix W Wehrli
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, PA 19104, USA
    J Magn Reson Imaging 25:390-409. 2007
    ..Current data suggest that noninvasive assessment of cortical and trabecular bone (TB) architecture by mu-MRI may provide new surrogate endpoints to assess the efficacy of intervention in osteoporosis treatment and prevention...
  26. ncbi request reprint Quantitative MRI for the assessment of bone structure and function
    Felix W Wehrli
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, PA 19104, USA
    NMR Biomed 19:731-64. 2006
    ..Key clinical applications targeted involve fracture risk prediction and evaluation of the effect of therapeutic intervention...
  27. ncbi request reprint Correcting bulk in-plane motion artifacts in MRI using the point spread function
    Wei Lin
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
    IEEE Trans Med Imaging 24:1170-6. 2005
    ..Rotation is detected by analyzing the relative displacements of two such markers. The technique was evaluated with simulations, phantom and in vivo experiments...
  28. pmc Computational biomechanics of the distal tibia from high-resolution MR and micro-CT images
    Chamith S Rajapakse
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
    Bone 47:556-63. 2010
    ..0.71+/-0.11) when correlated with reference subregional elastic and shear moduli. This work suggests that elastic properties of distal tibia can be reliably estimated by microFE analysis from microMRIs obtainable at in vivo resolution...
  29. ncbi request reprint A theoretical and experimental investigation of the tagging efficiency of pseudocontinuous arterial spin labeling
    Wen Chau Wu
    Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
    Magn Reson Med 58:1020-7. 2007
    ..These improvements provide a better balance between tagging efficiency and SNR...
  30. ncbi request reprint Visualization of individual axons in excised lamprey spinal cord by magnetic resonance microscopy
    Alexander C Wright
    Laboratory for Structural NMR Imaging, Department of Radiology, 1 Silverstein, Hospital of the University of Pennsylvania, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, PA 19104, USA
    J Neurosci Methods 114:9-15. 2002
    ..Although the lamprey previously has not been the subject of MR microscopy investigations, these results demonstrate the method's potential for imaging this axon system, which is an important model of spinal cord injury and regeneration...
  31. pmc Mechanical implications of estrogen supplementation in early postmenopausal women
    Felix W Wehrli
    Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
    J Bone Miner Res 25:1406-14. 2010
    ..The data further highlight the anabolic effect of short-term estrogen supplementation...
  32. ncbi request reprint Multislice double inversion pulse sequence for efficient black-blood MRI
    Hee Kwon Song
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania, USA
    Magn Reson Med 47:616-20. 2002
    ..It is demonstrated in vivo with examples from carotid and coronary arteries that one can acquire multiple slices with sufficient nulling of blood, following a single set of inversion pulses...
  33. ncbi request reprint Noninvasive assessment of bone microarchitecture by MRI
    Glenn A Ladinsky
    Division of Renal, Electrolytes and Hypertension, University of Pennsylvania, 700 Clinical Research Bldg, 415 Curie Blvd, Philadelphia, PA 19104 4218, USA
    Curr Osteoporos Rep 4:140-7. 2006
    ..This technique is noninvasive, involving no contrast or ionizing radiation, and provides useful clinical information independent of bone mineral density, thereby allowing for better classification of those at high risk for fracture...
  34. pmc Classification of trabeculae into three-dimensional rodlike and platelike structures via local inertial anisotropy
    Branimir Vasilic
    Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
    Med Phys 36:3280-91. 2009
    ..Finally, the method is applied to data acquired in a previous translational pilot study showing that the trabecular bone of untreated hypogonadal men is less platelike than that of their eugonadal peers...
  35. doi request reprint Fast prospective registration of in vivo MR images of trabecular bone microstructure in longitudinal studies
    Chamith S Rajapakse
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania School of Medicine, 3400 Spruce Street, Philadelphia, PA 19104, USA
    Magn Reson Med 59:1120-6. 2008
    ..Based on phantom and human subject studies it is shown that prospective registration yields very close matching between baseline and follow-up imaging volumes...
  36. pmc Implications of noise and resolution on mechanical properties of trabecular bone estimated by image-based finite-element analysis
    Chamith S Rajapakse
    Department of Radiology, Laboratory for Structural NMR Imaging, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
    J Orthop Res 27:1263-71. 2009
    ..Systematic errors manifesting in significant deviations of the slopes from unity are caused by higher apparent bone-volume fraction of the MR images but can potentially be corrected with appropriate histogram-standardization techniques...
  37. ncbi request reprint Measurement of trabecular bone thickness in the limited resolution regime of in vivo MRI by fuzzy distance transform
    Punam K Saha
    Medical Image Processing Group, Department of Radiology, University of Pennsylvania, Fourth Floor, Blockley Hall, 423 Guardian Drive, Philadelphia, PA 19104 6021, USA
    IEEE Trans Med Imaging 23:53-62. 2004
    ..Finally, with in vivo micro-MR images from a prior study in rabbits subjected to corticosteroid exposure, it is demonstrated that short-term treatment resulting in trabecular thinning can be quantified with the new method...
  38. ncbi request reprint Water content measured by proton-deuteron exchange NMR predicts bone mineral density and mechanical properties
    Maria A Fernandez-Seara
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104, USA
    J Bone Miner Res 19:289-96. 2004
    ..Water content showed an inverse relationship with mineral content, suggesting it could serve as a surrogate measure for the bone's degree of mineralization...
  39. ncbi request reprint Reference-scan-free method for automated correction of Nyquist ghost artifacts in echoplanar brain images
    Yan Zhang
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104, USA
    Magn Reson Med 51:621-4. 2004
    ..In vivo data demonstrate the effectiveness of the algorithm showing ghost suppression comparable to that achievable with the reference-scan method...
  40. ncbi request reprint Quantitative high-resolution magnetic resonance imaging reveals structural implications of renal osteodystrophy on trabecular and cortical bone
    Felix W Wehrli
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104, USA
    J Magn Reson Imaging 20:83-9. 2004
    ....
  41. pmc Diffusion of exchangeable water in cortical bone studied by nuclear magnetic resonance
    Maria A Fernandez-Seara
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104, USA
    Biophys J 82:522-9. 2002
    ..Finally, the data reveal a water component (approximately 30%) diffusing four orders of magnitude more slowly, which is ascribed to water tightly bound to the organic matrix and mineral phase...
  42. doi request reprint Vertebral deformities and fractures are associated with MRI and pQCT measures obtained at the distal tibia and radius of postmenopausal women
    C S Rajapakse
    University of Pennsylvania School of Medicine, Philadelphia, PA, USA
    Osteoporos Int 25:973-82. 2014
    ..Distal extremity measures showed variable degrees of association with vertebral deformities and fractures, highlighting the systemic nature of postmenopausal bone loss...
  43. ncbi request reprint Fast low-angle dual spin-echo (FLADE): a new robust pulse sequence for structural imaging of trabecular bone
    J Magland
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, PA 19104, USA
    Magn Reson Med 55:465-71. 2006
    ..Structural parameters derived from the in vivo images with the two pulse sequences are highly correlated, therefore suggesting that clinical data obtained with either pulse sequence can be merged...
  44. ncbi request reprint General algorithm for automated off-center MRI
    J Magland
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104, USA
    Magn Reson Med 56:230-3. 2006
    ....
  45. ncbi request reprint Coherence-induced artifacts in large-flip-angle steady-state spin-echo imaging
    Branimir Vasilic
    Laboratory for Structural NMR Imaging, University of Pennsylvania Medical Center, Department of Radiology, Philadelphia, Pennsylvania 19104, USA
    Magn Reson Med 52:346-53. 2004
    ..The results of the simulations were in exact agreement with the experiments and the proposed remedy was found to eliminate the artifact...
  46. pmc Indirect measurement of regional axon diameter in excised mouse spinal cord with q-space imaging: simulation and experimental studies
    Henry H Ong
    Department of Radiology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
    Neuroimage 40:1619-32. 2008
    ..QSI may be able to quantify nondestructively changes in WM axon architecture due to pathology or injury at the cellular level...
  47. ncbi request reprint A new approach for simultaneous measurement of ADC and T2 from echoes generated via multiple coherence transfer pathways
    Henry Ong
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, PA, USA
    J Magn Reson 173:153-9. 2005
    ..The regional SMART derived T2 and ADC agree well with those obtained with conventional double-spin-echo and pulsed gradient spin-echo methods...
  48. pmc In vivo NMR microscopy allows short-term serial assessment of multiple skeletal implications of corticosteroid exposure
    Masaya Takahashi
    Department of Radiology, University of Pennsylvania Medical Center, 1 Silverstein, 3400 Spruce Street, Philadelphia, PA 19104, USA
    Proc Natl Acad Sci U S A 99:4574-9. 2002
    ..Finally, this work, which was performed on a clinical scanner, has implications for evaluating patients on high-dose steroid treatment...
  49. ncbi request reprint Topology-based orientation analysis of trabecular bone networks
    Bryon R Gomberg
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
    Med Phys 30:158-68. 2003
    ..16, 1520 (2001)] shows that the mean orientation and anisotropy at the medial and lateral sides in the distal radius mataphyseal trabecular network are consistent with the mechanical stresses acting on the radius during common tasks...
  50. pmc Magnetic resonance microimaging of intraaxonal water diffusion in live excised lamprey spinal cord
    Masaya Takahashi
    Departments of Radiology and Neurology, University of Pennsylvania Medical Center, 1 Silverstein, 3400 Spruce Street, Philadelphia, PA 19104 USA
    Proc Natl Acad Sci U S A 99:16192-6. 2002
    ..These findings support the hypothesis that the cell membrane is the primary source of diffusion anisotropy in fiber tracts of the central nervous system...
  51. pmc In vivo magnetic resonance detects rapid remodeling changes in the topology of the trabecular bone network after menopause and the protective effect of estradiol
    Felix W Wehrli
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
    J Bone Miner Res 23:730-40. 2008
    ....
  52. pmc Quantifying axon diameter and intra-cellular volume fraction in excised mouse spinal cord with q-space imaging
    Henry H Ong
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
    Neuroimage 51:1360-6. 2010
    ..92, p<0.05) with measurements from histology (0.68+/-0.07). These methods may provide insight into axonal architecture in normal and abnormal WM tissue but additional validation with more samples will be needed...
  53. ncbi request reprint Structural MRI of carotid artery atherosclerotic lesion burden and characterization of hemispheric cerebral blood flow before and after carotid endarterectomy
    C E Jones
    Department of Radiology, Neuroradiology Section, University of Pennsylvania Medical Center, Philadelphia, 19104, USA
    NMR Biomed 19:198-208. 2006
    ..Unilateral ASL may better predict hemodynamic surgical outcome (measured by improved perfusion) than ICA OR...
  54. ncbi request reprint Biexponential diffusion attenuation in the rat spinal cord: computer simulations based on anatomic images of axonal architecture
    Chih Liang Chin
    Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104, USA
    Magn Reson Med 47:455-60. 2002
    ....
  55. pmc MRI estimation of global brain oxygen consumption rate
    Varsha Jain
    Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104, USA
    J Cereb Blood Flow Metab 30:1598-607. 2010
    ..In addition, the short acquisition time (approximately 30 seconds) makes the technique suitable for studying the temporal variations in CMRO(2) in response to physiologic challenges...
  56. ncbi request reprint Retrospective correction for induced magnetic field inhomogeneity in measurements of large-vessel hemoglobin oxygen saturation by MR susceptometry
    Michael C Langham
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104, USA
    Magn Reson Med 61:626-33. 2009
    ....
  57. ncbi request reprint Subvoxel processing: a method for reducing partial volume blurring with application to in vivo MR images of trabecular bone
    Scott N Hwang
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104, USA
    Magn Reson Med 47:948-57. 2002
    ..The subvoxel-processed images are shown to have architectural features characteristic of images acquired at higher spatial resolution...
  58. pmc High-resolution black-blood MRI of the carotid vessel wall using phased-array coils at 1.5 and 3 Tesla
    Seshasailaja Anumula
    Department of Radiology, Laboratory for Structural NMR Imaging, University of Pennsylvania Health System, Philadelphia, PA, USA
    Acad Radiol 12:1521-6. 2005
    ..5 and 3 Tesla (T) and determine the extent to which the improved SNR at the higher field can be traded for improved spatial resolution...
  59. pmc Trabecular structure quantified with the MRI-based virtual bone biopsy in postmenopausal women contributes to vertebral deformity burden independent of areal vertebral BMD
    Glenn A Ladinsky
    Division of Renal, Electrolytes and Hypertension, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania, USA
    J Bone Miner Res 23:64-74. 2008
    ....
  60. pmc Cortical bone water: in vivo quantification with ultrashort echo-time MR imaging
    Aranee Techawiboonwong
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce St, 1 Founders, MRI Education Center, Philadelphia, PA 19104, USA
    Radiology 248:824-33. 2008
    ..To develop and evaluate a method based on ultrashort echo-time radial magnetic resonance (MR) imaging to quantify bone water (BW) concentration as a new metric of bone quality in human cortical bone in vivo...
  61. ncbi request reprint Multipoint mapping for imaging of semi-solid materials
    M A Fernández-Seara
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
    J Magn Reson 160:144-50. 2003
    ..The method's potential is illustrated with 3D proton images of short-T(2) materials such as synthetic polymers and bone...
  62. ncbi request reprint Reproducibility and error sources of micro-MRI-based trabecular bone structural parameters of the distal radius and tibia
    B R Gomberg
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania, Philadelphia 19104, USA
    Bone 35:266-76. 2004
    ..68 to 0.92 in the tibia. Error analysis based on simulations suggests involuntary patient motion, primarily rotation, to be the chief source of imprecision, followed by failure to accurately match the analysis volumes in repeat studies...
  63. pmc Water magnetic relaxation dispersion in biological systems: the contribution of proton exchange and implications for the noninvasive detection of cartilage degradation
    U Duvvuri
    Department of Radiology, Metabolic Magnetic Resonance Research and Computing Center, University of Pennsylvania, Philadelphia, PA 19104, USA
    Proc Natl Acad Sci U S A 98:12479-84. 2001
    ..Further, low frequency dispersion changes are correlated with loss of proteoglycan from the extra-cellular matrix of articular cartilage. This finding has significance for the noninvasive detection of matrix degradation...
  64. ncbi request reprint Effect of testosterone replacement on trabecular architecture in hypogonadal men
    Maria Benito
    Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104 6149, USA
    J Bone Miner Res 20:1785-91. 2005
    ..After 2 years, microMRI parameters of trabecular connectivity improved significantly, suggesting the possibility that testosterone improves trabecular architecture...
  65. ncbi request reprint Quantitative magnetic resonance imaging in the calcaneus and femur of women with varying degrees of osteopenia and vertebral deformity status
    Felix W Wehrli
    Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104, USA
    J Bone Miner Res 17:2265-73. 2002
    ..01). The data suggest the calcaneus to be suited as a surrogate site to assess vertebral osteoporosis and that R2* is sensitive to alterations in bone quality not captured by density...
  66. pmc Accuracy and precision of MR blood oximetry based on the long paramagnetic cylinder approximation of large vessels
    Michael C Langham
    Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, PA 19104, USA
    Magn Reson Med 62:333-40. 2009
    ..In conclusion, the data suggest that %HbO(2) can be measured reproducibly in vivo in large vessels of the peripheral circulation on the basis of the paramagnetic cylinder approximation of the incremental field...
  67. ncbi request reprint MR susceptometry for measuring global brain oxygen extraction
    Maria A Fernandez-Seara
    Center for Functional Neuroimaging, Department of Neurology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104, USA
    Magn Reson Med 55:967-73. 2006
    ..Unlike alternative methods, the susceptometric technique does not require calibration...
  68. ncbi request reprint In vivo MRI of submillisecond T(2) species with two-dimensional and three-dimensional radial sequences and applications to the measurement of cortical bone water
    Aranee Techawiboonwong
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, PA 19104, USA
    NMR Biomed 21:59-70. 2008
    ..With the use of an external reference, the water volume fraction of cortical bone in four subjects (mean +/- SD age 32.25 +/- 5.3 years) was found to be 22.5 +/- 2.7%, in good agreement with literature values...
  69. ncbi request reprint Isolating quantum coherences in structural imaging using intermolecular double-quantum coherence MRI
    Chih Liang Chin
    Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, PA 19104 4283, USA
    J Magn Reson 165:309-14. 2003
    ..Finally, preliminary data suggest the method to be able to provide information on trabecular bone architecture such as regional mean trabecular plate separation...
  70. pmc Hyperemic flow heterogeneity within the calf, foot, and forearm measured with continuous arterial spin labeling MRI
    Wen Chau Wu
    Department of Radiology, The Hospital of University of Pennsylvania, 3400 Spruce St, Philadelphia, PA 19104, USA
    Am J Physiol Heart Circ Physiol 294:H2129-36. 2008
    ..These results demonstrate that CASL is sensitive to flow heterogeneity between diverse muscle groups and that nonuniform hyperemic flow patterns following an ischemic paradigm correlate with relative fiber-type predominance...
  71. ncbi request reprint Spatially-confined arterial spin-labeling with FAIR
    Yan Zhang
    Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104, USA
    J Magn Reson Imaging 22:119-24. 2005
    ..To investigate the effectiveness of slab-selective inversion in pulsed arterial spin labeling with body coil excitation as a means to reduce large vessel contamination of the perfusion signal...
  72. pmc Complete volumetric decomposition of individual trabecular plates and rods and its morphological correlations with anisotropic elastic moduli in human trabecular bone
    X Sherry Liu
    Bone Bioengineering Laboratory, Department of Biomedical Engineering, Columbia University, New York, NY 10027, USA
    J Bone Miner Res 23:223-35. 2008
    ..The ITS-based morphological analyses better characterize microarchitecture and help predict anisotropic mechanical properties of trabecular bone...
  73. pmc Quantification of the roles of trabecular microarchitecture and trabecular type in determining the elastic modulus of human trabecular bone
    Xiaowei S Liu
    Bone Bioengineering Laboratory, Department of Biomedical Engineering, Columbia University, New York, New York 10027, USA
    J Bone Miner Res 21:1608-17. 2006
    ..The results suggest that trabecular plates play an essential role in determining elastic properties of trabecular bone...
  74. ncbi request reprint Experimental and computational analyses of the effects of slice distortion from a metallic sphere in an MRI phantom
    Tim A J Hopper
    School of Physical and Chemical Sciences, Queensland University of Technology, GPO Box 2434, Brisbane 4001, Australia
    Magn Reson Imaging 24:1077-85. 2006
    ....
  75. ncbi request reprint Magnetization transfer micro-MR imaging of live excised lamprey spinal cord: characterization and immunohistochemical correlation
    Hidemasa Uematsu
    Department of Radiology, University of Fukui, 23 Shimoaizuki, Matsuoka cho, Yoshida gun, Fukui, 910 1193, Japan
    AJNR Am J Neuroradiol 25:1816-20. 2004
    ..These characteristics permit determination of the effect of cell membrane density on MT. The purpose of this study was to characterize regional MT effects in lamprey spinal cord...
  76. ncbi request reprint [Micro MRI of trabecular bone]
    Masaya Takahashi
    Harvard Medical School, Department of Radiology, Beth Israel Deaconess Medical Center
    Clin Calcium 14:47-54. 2004
    ..Surfaces and curves are the lower-dimensionality counterparts of plates and rods for better differentiation of bone quality...
  77. ncbi request reprint Structural anisotropy and internal magnetic fields in trabecular bone: coupling solution and solid dipolar interactions
    Louis S Bouchard
    Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
    J Magn Reson 176:27-36. 2005
    ..A simple calculation using a priori knowledge of the material geometry and distribution of internal magnetic fields verifies the experimental measurements as a function of gradient strength, direction, and sample orientation...
  78. ncbi request reprint Quantitative microcomputed tomography assessment of intratrabecular, intertrabecular, and cortical bone architecture in a rat model of severe renal osteodystrophy
    Tim A J Hopper
    School of Physical and Chemical Sciences, Queensland University of Technology, Brisbane, Australia
    J Comput Assist Tomogr 31:320-8. 2007
    ..To determine the effects of renal osteodystrophy (ROD) on bone microarchitecture in growing rats...
  79. ncbi request reprint Deterioration of trabecular architecture in hypogonadal men
    Maria Benito
    Department of Medicine, University of Pennsylvania, Phyladelphia 19104, USA
    J Clin Endocrinol Metab 88:1497-502. 2003
    ..We conclude that male hypogonadism is associated with marked deterioration of trabecular architecture and to a greater degree than bone densitometry of the spine and hip suggests...
  80. ncbi request reprint An image-based finite difference model for simulating restricted diffusion
    Scott N Hwang
    New York University Medical Center, Combined Neurology Radiology Neuroradiology Program, New York, New York, USA
    Magn Reson Med 50:373-82. 2003
    ....
  81. pmc In vivo microMRI-based finite element and morphological analyses of tibial trabecular bone in eugonadal and hypogonadal men before and after testosterone treatment
    X Henry Zhang
    Department of Biomedical Engineering, Columbia University, New York, New York 10027, USA
    J Bone Miner Res 23:1426-34. 2008
    ..These results suggest that 24 mo of testosterone treatment of hypogonadal men improves estimated elastic moduli of tibial trabecular bone by increased trabecular plate thickness...
  82. ncbi request reprint NMR of the musculoskeletal system
    Felix W Wehrli
    NMR Biomed 19:721-2. 2006
  83. ncbi request reprint On the 2003 Nobel Prize in medicine or physiology awarded to Paul C. Lauterbur and Sir Peter Mansfield
    Felix W Wehrli
    Magn Reson Med 51:1-3. 2004