Quantitative MRI of Fibrocartilage
Tuesday 21 April 2009
Room 312 13:30-15:30

Moderators:

 Garry E. Gold and Timothy J. Mosher
 
13:30  288. T1ρ Imaging and Quantification of the Meniscus Using a T1ρ -Prepared Ultrashort TE (T1ρ -UTE) Sequence
    Jiang Du1, Michael Carl2, Atsushi M. Takahashi2, Eric Diaz1, Christine B. Chung1, Eric Han2, Graeme M. Bydder1
1Radiology, University of California-San Diego, San Diego, CA, USA; 2Global Applied Science Laboratory, GE Healthcare Technologies, Menlo Park, CA, USA
    Osteoarthritis is a multisystemic degenerative joint disease affecting not only articular cartilage, but also subchondral bone, synovium, the joint capsule and meniscii. Recently there has been increased interest in imaging and quantifying the impact of the disease on the meniscus. Meniscii appear low signal on the morphological images and accurate quantification may be challenging. Ultrashort TE (UTE) sequences with a TE of 8 ƒÝs provide high signal intensity of the meniscus, and improved confidence in quantification. Here we describe a UTE sequence designed to image and quantify T1ƒâ and T2* of the meniscus on a clinical 3T scanner.
     
13:42 289. Variability of Meniscal T2* Calculations Using Ultra-Short Echo (UTE) Imaging
    Matthew F. Koff1, Atsushi Takahashi2, Hollis Potter1
1Department of Radiology and Imaging, Hospital for Special Surgery, New York, NY, USA; 2Applied Science Laboratory, GE Healthcare, Menlo Park, CA, USA
    The knee meniscus typically displays low signal on standard clinical images. Ultrashort echo (UTE) imaging creates contrast for meniscal visualization and T2* quantitation. This study evaluated the effects of UTE acquisition resolution and inter-echo timings on calculated T2* values. Ex-vivo sheep knees were scanned and the number of arms and inter-echo times of the radial sequence were varied. Higher resolution and longer inter-echo spaced images produced longer T2* values. The average maximum T2* difference from all methods was 1.2ms. This study will aid in the development of optimal UTE scanning parameters for clinical investigation of the meniscus.
   

 
13:54 290. Delayed Contrast Enhanced MRI of Meniscus
    Wei Li1, Robert R. Edelman1, Pottumarthi V. Prasad1
1Department of Radiology, Center of Advanced Imaging, NorthShore University HealthSystem, Evanston, IL, USA
    A retrospective analysis of T10 and T1Gd in menisci, including inner and outer zones, was performed in 10 OA patients and 8 healthy subjects (HS). Data were acquired with a 3DLL sequence using ionic and non-ionic contrast agents. Compared to HS, the mean T10 of meniscus in OA was slightly higher, but T1Gd was lower. The meniscus showed a modest correlation with articular cartilage in T1Gd, with little difference in T1 between the two zones. There was a correspondence closed to 1:1 in T1Gd with the two agents. These findings collectively suggest minimal GAG based contrast distribution within the meniscus.
     
14:06 291. Optimizing MR Signal Contrast of the TMJ Disk
    Michael Carl1, Hatice T. Sanal2, Eric Diaz2, Jiang Du2, Olivier Maciej Girard2, Sheronda Statum2, Richard Znamirowski2, Christine Chung2
1GE Healthcare, Applied Science Lab, Milwaukee, WI, USA; 2Radiology, University of California, San Diego, CA, USA
    The temporomandibular joint is a unique articulation that demonstrates both structural and functional complexity. These tissues comprised largely of short T2 components are challenging as conventional MR sequences are limited in their ability to detect signal from them, as well as produce contrast between the fibrocartilaginous disc and articular surfaces. In this study, we use a tissue specific algorithm that will optimize contrast based on knowledge of intrinsic MR properties of tissues and Bloch equations dictating signal and contrast. This approach to image optimization could be instrumental in improving diagnostic capabilities in the clinical setting.
     
14:18 292. Mechanical and Biochemical Characterization of the Degenerated Rabbit Intervertebral Disc by MRI
   

Deva D. Chan1, Safdar N. Khan2, Xiaojing Ye3, Shane B. Curtiss3, Munish C. Gupta2, Eric Klineberg2, Corey P. Neu1
1Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA; 2Orthopedic Surgery, University of California - Davis Medical Center, Sacramento, CA, USA; 3Center for Tissue Regeneration and Repair, University of California - Davis Medical Center, Sacramento, CA, USA
    An intervertebral disc degeneration model in New Zealand white rabbit was characterized biochemically with delayed gadolinium enhanced MRI of cartilage (dGEMRIC) and mechanically with displacement-encoded stimulated echoes with fast spin echo readout (DENSE-FSE). Glucosaminoglycan content, as measured with dGEMRIC, was significantly decreased in degenerated discs, as expected and confirmed by histology. Deformations within the volume of the disc during cyclic compression demonstrated clear changes in mechanical behavior with degeneration.
   

 
14:30 293. Assessing the Inververtebral Disc Via GagCEST
    Wen Ling1, Galit Saar2, Ravinder R. Regatte3, Alexej Jerschow4, Gil Navon2
1CMRR, Univ. of Minnesota, Minneapolis, MN, USA; 2School of Chem., Tel Aviv Univ., Ramat Aviv, Tel Aviv, Israel; 3Dept. of Radiology, NYU, New York, NY, USA; 4Chem. Dept., NYU, NYU, NY, USA
    Synopsis: The loss of the proteoglycans is thought to be an initiating event of disc degeneration. Therefore, the ability to detect these early events is of crucial importance to facilitate earlier intervention, to monitor the effectiveness of treatments, and to study the mechanism of disease progression. We demonstrate here the possibility of a MRI strategy based on glycosaminoglycan chemical exchange saturation transfer (gagCEST), which would allow one to detect the loss of proteoglycans within the disc. Our results show that gagCEST can be used to monitor early signs of disc degeneration.
     
14:42 294. Sodium MRI of Intervertebral Disc Degeneration
   

Chenyang Michael Wang1, Erin McArdle2, Walter Witschey3, Mark Elliott2, Ravi Reddy2, Ari Borthakur2
1Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; 2Radiology, University of Pennsylvania; 3Biophysics and Molecular Biology, University of Pennsylvania
    Intervertebral disc degeneration is a common and sometimes painful condition. The initial sign of intervertebral disc degeneration involves the breakdown of proteoglycans, and current diagnostic measure for the condition is not sensitive to it. Sodium MRI has previously been used to study proteoglycan depletion in articular cartilage. In this study, we conducted high-resolution sodium MRI on ex vivo bovine intervertebral discs samples, and correlated sodium MRI result with 1,9-dimethylmethylene blue proteoglycan assay results. Our results demonstrated the potential for sodium MRI to become a non-invasive diagnostic tool for early stage intervertebral disc degeneration.
   

 
14:54 295. Correlation Between Apparent Diffusion Coefficient Values and Pfirrmann Grades of Lumbar Intervertebral Disc Degeneration
    Hon J. Yu1, Shadfar Bahri1, Lutfi Tugan Muftuler1, Orhan Nalcioglu1, Vance Gardner2
1Tu & Yuen Center for Functional Onco-Imaging, University of California, Irvine, CA, USA; 2Orthopaedic Education and Research Institute of Southern California, Orange, CA, USA
    The level of degeneration was graded on 5-level Pfirrmann classification system and its correlation with ADC values was investigated in vivo using 166 lumbar intervertebral discs (IVD). The ADC values from the whole IVD were obtained on a pixel-by-pixel basis and then grouped for each Pfirrman grade for comparison. The mean population values of ADC amongst the 5 groups differed significantly and showed an inversely proportional trend with respect to the grades (1: normal; 5: severe degeneration). A 5-bin histogram analysis of the ADC values exhibited a characteristic distribution of ADC values for each group, perhaps revealing different degenerative-related changes taking place in nucleus pulposus and annulus fibrosus of IVD.
     
15:06 296. Self-Coregistered T1ρ and Sodium MRI of Intervertebral Discs
    Chenyang Michael Wang1, Walter Witschey, Erin McArdle, Mark Elliott2, Ari Borthakur2, Ravi Reddy2
1Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; 2Radiology, University of Pennsylvania
    Intervertebral disc degeneration is a common and sometimes debilitating condition. Current diagnostic technique for intervertebral disc degeneration is not sensitive to the initial phase of degeneration, which involves the breakdown of proteoglycans. T1ρ is a non-invasive MRI technique that has been shown to be sensitive to interaction between macromolecules and bulk water. Sodium MRI has already been shown to be sensitive to proteoglycan change in tissue. In this study, we carried out sodium MRI and T1ρ MRI on ex vivo bovine intervertebral disc, and demonstrated linear correlation between the two measurements.
     
15:18 297. Degeneration of the Long Biceps Tendon of the Shoulder: Comparison of MR Imaging with Gross Anatomy and Histology
    Florian M. Buck1, Holger Grehn2, Monika Hilbe3, Silvana Manzanell4, Juerg Hodler1
1Department of Radiology, Balgrist University Hospital, Zurich, Switzerland; 2Orthopedic Surgery, Balgrist University Hospital, Zurich, Switzerland; 3Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland; 4MSRU, Equine Hospital, Vetsuisse Faculty, University of Zurich, Zurich, ZH, Switzerland
    Problem: Diagnosis of biceps tendinopathy in the shoulder is difficult (artifacts, complex anatomy, degeneration).  Method: Evaluation of tendon caliber and signal in MRI and comparison with gross anatomy and histology in cadaveric specimen. Results:  Agreement between gross anatomy and MRI was moderate to strong. Agreement between MRI and histology concerning the location of tendon degeneration was good. A diameter alteration always concurred with a tendon degeneration histologically. Conclusion:  Biceps tendon caliber changes are specific for tendinopathy but lack sensitivity. Signal changes are useful in the diagnosis of tendinopathy although none of the employed sequences in isolation demonstrated histological changes precisely.