ISMRM 21st Annual Meeting & Exhibition 20-26 April 2013 Salt Lake City, Utah, USA

Bone, Tendon & Menisci: State of the Art
Monday 22 April 2013
Room 255 BC  16:30 - 18:30 Moderators: Erik Y. Chang, Mark D. Does

16:30 0141.   Aging Augments the Suppression Ratio, a MRI Biomarker of Cortical Bone Porosity
Yusuf A. Bhagat1, Cheng Li1, Shing Chun Benny Lam1, Alan C. Seifert1, Mahdieh Bashoor Zadeh1, and Felix W. Wehrli1
1Laboratory for Structural NMR Imaging, University of Pennsylvania, Philadelphia, PA, United States

The pore water fraction of cortical bone water is known to increase with age. Here, 3T-based ultra-short echo-time (UTE) MRI of the mid-diaphyseal tibia was used to evaluate the potential of the suppression ratio (SR, unsuppressed to soft-tissue suppressed UTE signal) as a surrogate parameter for porosity in 39 healthy women (24-81 years) and in 13 cortical bone specimens from human donors (27-97 years). SR was strongly associated with age and correlated with micro-CT-derived porosity. SR may serve as an in vivo biomarker of porosity in lieu of more involved methods such as bi-component T2* analysis.

16:42 0142.   Can We Assess Cortical Bone Microstructure with Magnetic Resonance Imaging?
Won C. Bae1, Reni Biswas1, Shantanu Patil2, Christine Chung1, Darryl D. D'Lima2, Graeme M. Bydder3, and Jiang Du1
1Radiology, University of California, San Diego, San Diego, CA, United States, 2Molecular and Experimental Medicine, Scripps Translational Science Institute, La Jolla, CA, United States, 3Radiology, University of California San Diego, San Diego, CA, United States

Bone water occurs at various locations and in different binding states, including water bound to organic matrix and free water residing in the microscopic pores of cortical bone. Cortical bone is typically regarded as “MR invisible” with conventional clinical MR sequences. In this study, we aimed to investigate bone water imaging with UTE and clinical FSE sequences, and to correlate the structure seen with FSE imaging with that seen with uCT imaging.

16:54 0143.   The Porous System Model Suitable to Investigate the Structural Properties of the Cancellous Bone by Using Diffusion Techniques: Validation in Calcaneus and Femoral Neck
Silvia Capuani1
1Physics Department, Sapienza University, Rome, Italy, Italy

A porous system model suitable to investigate the structural properties of the cancellous bone by using diffusion techniques is shown. To validate the model, the calcaneus and the femoral neck of healthy, osteopenic and osteoporotic subjects, as classified by the bone mineral density (BMD) were investigated by measuring the apparent diffusion coefficient (ADC), together with the marrow fat content (Mfc) and assessing associations between BMD, Mfc and ADC. In calcaneus cancellous bone, a microstructure deterioration with a pore enlargement due to osteoporosis, increases ADC. Diffusion assessment obtained in large populations, might increase our pathophysiological understanding of osteoporosis.

17:06 0144.   Assessment of Bone Marrow Fat Fraction in the Presence of Trabecular Bone: Initial Comparison of Water-Fat Imaging with Single-Voxel MRS
Dimitrios C. Karampinos1,2, Gerd Melkus1, Thomas Baum2, Jan S. Bauer2, Ernst J. Rummeny2, and Roland Krug1
1Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, United States, 2Department of Diagnostic and Interventional Radiology, Technical University of Munich, Munich, Germany

Single-voxel MR spectroscopy has been the technique of choice for measuring fat content in localized bone marrow regions. However, there is a growing interest on applying quantitative water-fat imaging techniques to measure bone marrow fat content with high spatial resolution. Bone marrow fat content measurements in the presence of trabecular bone are hindered by strong susceptibility effects and short T2*. The present study describes our preliminary findings in comparing bone marrow fat fraction measurements in the presence of trabecular bone using water-fat imaging and single-voxel MRS. A good agreement was found between the two techniques after accounting for the effect of short T2* species.

17:18 0145.   Variation of Lamellar Layer Thickness in Human Menisci on Ultrashort Echo Time (UTE) Imaging: Correlation with Indentation Stiffness
Ja-Young Choi1, Reni Biswas2, Mike Im1, Won C. Bae1, Sheronda Statum1, Eric Chang2, Jiang Du2, Graeme M. Bydder3, Darryl D. D'Lima4, and Christine Chung2
1Radiology, UC San Diego Medical Center, San Diego, California, United States, 2Radiology, University of California, San Diego, San Diego, California, United States,3Radiology, University of California San Diego, San Diego, California, United States, 4Molecular and Experimental Medicine, Scripps Translational Science Institute, La Jolla, California, United States

In this study, variation of lamellar layer thickness in normal human menisci was evident on 2D UTE images, and femoral lamellar layers were found to be significantly thicker than tibial ones. Moreover, the thickness significantly correlated with surface indentation stiffness.

17:30 0146.   Correlation Between Quantitative Delayed Contrast-Enhancement in Meniscus and Cartilage in Knee Osteoarthritis
Jasper van Tiel1,2, Esther Bron1,3, Koen Bos2, Stefan Klein1,3, Max Reijman2, Jan Verhaar2, Gabriel Krestin1, Harrie Weinans2,4, Gyula Kotek1, and Edwin Oei1
1Radiology, Erasmus MC, Rotterdam, Zuid-Holland, Netherlands, 2Orthopedic Surgery, Erasmus MC, Rotterdam, Zuid-Holland, Netherlands, 3Medical Informatics, Erasmus MC, Rotterdam, Zuid-Holland, Netherlands, 4Biomechanical Engineering, Delft University of Technology, Delft, Zuid-Holland, Netherlands

We investigated the relation between delayed contrast-enhancement of an ionic contrast agent in the meniscus and adjacent cartilage in early stage knee osteoarthritis patients. We observed a moderate to strong relation between contrast uptake into both structures after a 1.5 hour delay. This finding is in agreement with the outcomes of previous research in which semi-quantitative whole joint assessment on MR images showed a relation between meniscal damage and cartilage loss. However, our results also raise a question about the specificity of delayed gadolinium-enhanced MRI of cartilage for sGAG content in (osteoarthritic) cartilage.

17:42 0147.   Experimental Influences on the Anisotropies of Multi-Component T2 and T1? in Tendon -permission withheld
Yang Xia1,2 and Nian Wang1
1Physics, Oakland University, Rochester, Michigan, United States, 2Center for Biomedical Research, Oakland University, Rochester, Michigan, United States

To study the anisotropic characteristics of multi-component T1ρ and T2 relaxation times in tendon, T2 and T1ρ were measured by NMR spectroscopy at different orientations and by microscopic MRI at the magic angle. Up to three T2 and T1ρ components were resolved in tendon. Both the values and the fractions of T2 in tendon showed significant orientational dependence. T1ρ strongly depended on both the specimen orientation and the spin-lock strength. The imaging resolution (35 – 280 µm) had little influence in the T2 experiments. The transitions between mono- and multi-component result call for the caution in interpreting the relaxation results.

17:54 0148.   The Shear Modulus of the Nucleus Pulposus Measured Using MR Elastography: A Potential Biomarker for Intervertebral Disc Degeneration
Daniel H. Cortes1, Jeremy F. Magland2, Alexander C. Wright2, and Dawn M. Elliott1
1Biomedical Engineering, University of Delaware, Newark, DE, United States, 2Radiology, University of Pennsylvania, Philadelphia, PA, United States

Intervertebral disc degeneration is characterized by a progressive cascade of biochemical and mechanical changes that affect its function. The structural changes characteristic of advanced degeneration are considered permanent due to the slow matrix turnover performed by disc cells. Therefore, early diagnosis of disc degeneration is critical for the success of any molecular or biological treatment. It is known that the shear modulus of the tissues in the disc changes significantly even for mild degeneration, and therefore it has potential for the diagnosis of early changes in the degeneration cascade. The objectives of the this study are: 1) to develop MRE methods to measure the shear modulus of the NP of intervertebral disc segments, 2) to quantify the effect of disc degeneration on the shear modulus measured using MRE, and 3) to compare the shear modulus to other MR-based biomarkers of disc degeneration.

18:06 0149.   Feasibility of Using MR Elastography in the Intervertebral Disc and Comparison to Finite Element Model
Ephraim I. Ben-Abraham1, Jun Chen1, and Richard Leroy Ehman1
1Mayo Clinic, Rochester, Minnesota, United States

Low back pain (LBP) is a very costly and prevalent health disorder in the U.S. One of the most common causes of LBP is degenerative disc disease (DDD). There are many techniques to characterize disc degeneration; however there is no way to directly assess the material properties of the intervertebral disc within the intact spine. Shear stiffness may be a more sensitive measure for DDD than current methods. In this study, we investigate the feasibility of using MRE to detect shear wave propagation in the intervertebral disc, and compare the experimental results with a finite element model of disc MRE.

18:18 0150.   DCEMRI Shows Slower Wash-Out in Lumbar Disc Endplates to Sustain Diffusion of Nutrients Into the Discs
L. Tugan Muftuler1,2, Hon J. Yu3, Vance O. Gardner4, and Dennis J. Maiman1
1Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, United States, 2Center for Imaging Research, Medical College of Wisconsin, Milwaukee, WI, United States, 3Department of Radiology, University of California, Irvine, CA, United States, 4Orthopaedic Education and Research Institute of Southern California, Orange, CA, United States

The IVD is avascular; nutrition is supplied via diffusion from the capillary beds of the cartilaginous vertebral body endplates. We are investigating perfusion characteristics in these capillary beds, disruption of which might cause poor nutrient delivery and lead to disc degeneration. We anticipated that the DCEMRI signal would be different in the endplate capillaries from those in bone marrow in adjacent vertebral bodies because of the different mechanisms of nutrient delivery to these two different systems. Our findings show slow wash-out in the endplates, which might be needed to maintain higher concentrations to sustain diffusion into the discs.