Weak in the Knees
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Wednesday May 11th
Room 710A  16:00 - 18:00 Moderators: Jiang Du and Siegfried Trattnig

16:00 498.   Cartilage Quality Assessment using gagCEST and Sodium MRI at 7 Tesla 
Benjamin Schmitt1, Stefan Zbyn2,3, David Stelzeneder2, Vladimir Jellus4, Dominik Paul4, Lars Lauer4, Peter Bachert1, and Siegfried Trattnig2
1Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany, 2Radiology, Medical University of Vienna, Vienna, Austria, 3Orthopedics, Medical University of Vienna, 4Siemens Healthcare, Erlangen, Germany

A new imaging method based on GRE that allows for acquisition of volumetric gagCEST image datasets in clinically relevant scan times is introduced. Reliability and glycosaminoglycan (GAG)-specificity are evaluated by comparison of results from the new technique to results obtained with sodium imaging in a patient study at 7 Tesla. All patients had cartilage repair surgery in the knee prior to examination, and a strong correlation be-tween gagCEST results, and sodium imaging was found. Cartilage repair regions could be equally well deline-ated from healthy cartilage with both imaging techniques.

16:12 499.   Quantitative and Morphologic Evaluation of Cartilage Repair in an Equine Model 
Sarah Pownder1, Matthew F Koff1, Lisa Fortier2, Emme Castiglione3, Ryan Saska3, Gino Bradica3, Kira Novakofski2, and Hollis G Potter1
1Department of Radiolgy and Imaging - MRI, Hospital for Special Surgery, New York, NY, United States, 2College of Veterinary Medicine, Cornell University, Ithaca, NY, United States, 3Kensey Nash Corporation

Evaluation of cartilage repair by MRI is largely based on subjective impressions of gray scale images. Quantitative MRI sequences such as T1 and T2 mapping measure tissue relaxation to assess the proteoglycan content and collagen organization, respectively. This study evaluated cartilage repair in an equine model using morphologic and quantitative MRI. The repair sites demonstrated regions of variable signal intensity, and the quantitative data indicated peripheral incorporation with native tissue, and diminished proteoglycan content and collagen orientation in the center of the repair. This study demonstrates the feasibility of MR evaluation of a preclinical model of cartilage repair at clinically relevant field strengths.

16:24 500.   Simultaneous Estimation of T2 and ADC in Human Articular Cartilage In Vivo with a Modified 3D DESS Sequence at 3 T 
Ernesto Staroswiecki1,2, Kristin Lee Granlund1,2, Marcus Tedrow Alley1, Garry Evan Gold1, and Brian Andrew Hargreaves1
1Radiology, Stanford University, Stanford, CA, United States, 2Electrical Engineering, Stanford University, Stanford, CA, United States

While ADC and T2 maps have been suggested as methods to obtain biochemical information generating them in cartilage is usually slow or limited by SAR, SNR, or distortion. In this work we present modifications to 3D DESS that enable manipulation of diffusion weighting of the sequence. We then acquire two datasets with this sequence with different weightings to generate two high-resolution images with different contrast and, by fitting to the signal equations, T2 and ADC maps. We show the accuracy of this method with a phantom study and demonstrate maps in vivo that are free of evident artifacts or distortion.

16:36 501.   In vivo DTI of articular cartilage: A new set of biomarkers for the early diagnosis of osteoarthritis 
Jose G Raya1, Annie Horng2, Olaf Dietrich2, Svetlana Krasnokutsky3, Luis S Beltran3, Maximilian F Reiser2, Michael Recht3, Michael Recht3, and Christian Glaser3
1Radiology, New York University Langone Medical Center, New York, NY, United States, 2University of Munich, 3New York University Langone Medical Center

In this work we assess the value of in vivo DTI of the articular cartilage for the early diagnosis of osteoarthritis (OA) at 7T using a 28Ch knee coil and a line scan diffusion sequence. DTI and T2 maps were obtained from 16 volunteers and 8 OA patients with early morphologic cartilage degeneration. Discrimination of the volunteer and patient were possible with mean ADC and FA (P<0.005) but not with T2. A cutoff of 1.210-3mm2 in average ADC and 0.4 in average FA resulted in a specificity of 100% and a sensitivity of 87.5% (positive predictive value=100%, negative predictive value=94.1%).

16:48 502.   Clinical Performance of 3D-FSE-Cube in the Upper Extremity 
Lauren Michelle Shapiro1, Deborah M Lee1, Karthryn J Stevens1, Weitian Chen2, Anja C Brau2, Brian A Hargreaves3, and Garry Evan Gold1,4
1Department of Radiology, Stanford University, Stanford, CA, United States, 2Applied Science Laboratory, GE Healthcare, Menlo Park, CA, United States, 3Department of Radiology, Stanford University, Stanford University, CA, United States, 4Department of Bioengineering, Stanford University, Stanford, CA, United States

Musculoskeletal MRI studies usually comprise of 2D-FSE sequences acquired in orthogonal planes. 3D-FSE enables isotropic voxel acquisition allowing reformations and decreased overall exam time. Thinner slice thickness in 3D-FSE also results in less partial volume artifact. We compare the clinical performance of 3D-FSE to 2D-FSE in evaluating the symptomatic upper extremity at 3.0T using arthroscopy as a reference standard. 3D-FSE showed similar performance to 2D-FSE in pathology identification in the upper extremity. The thinner slices of 3D-FSE, and the ability to reformat images in arbitrary planes, enabled optimal visualization of smaller and oblique pathology.

17:00 503.   Rapid Multi-Planar Assessment of the Articular Cartilage of the Knee Joint Using Isotropic Resolution VIPR-ATR Imaging  -permission withheld
Richard Kijowski1, Jessica Klaers2, Kenneth Lee1, Humberto Rosas1, Larry Hernandez2, and Walter Block2,3
1Radiology, University of Wisconsin, Madison, Wisconsin, United States, 2Medical Physics, University of Wisconsin, Madison, Wisconsin, United States, 3Biomedical Engineering, University of Wisconsin, Madison, Wisconsin, United States

The study was performed to compare SNR, CNR, and subjective criteria of image quality of VIPR-ATR and currently used three-dimensional MR sequences for evaluating the articular cartilage of the knee joint. VIPR-ATR produced multi-planar images of the knee joint with 0.4 mm isotropic resolution in 5 minutes and 0.3 mm isotropic resolution in 8 minutes which were well suited for evaluating articular cartilage. VIPR-ATR had high cartilage SNR and high CNR between cartilage and adjacent joint structure. On subjective analysis, VIPR-ATR had the highest rank for tissue contrast, clarity of articular surface, cartilage lesion conspicuity, and overall image quality.

17:12 504.   A B1-insensitive High Resolution 2D T1 Mapping Pulse Sequence for Radial dGEMRIC of the Hip at 3T 
Riccardo Lattanzi1,2, Christian Glaser1,2, Artem V Mikheev2, Catherine Petchprapa2, David J Mossa2, Soterios Gyftopoulos2, Henry Rusinek2, Michael Recht2, and Daniel Kim1,2
1Center for Biomedical Imaging, New York University Langone Medical Center, New York, NY, United States, 2Radiology, New York University Langone Medical Center, New York, NY, United States

Early detection of cartilage degeneration in the hip with dGEMRIC may help prevent osteoarthritis in patients with femoroacetabular impingement. We propose a new high-resolution 2D T1-mapping saturation-recovery (SR) pulse sequence with FSE readout for dGEMRIC at 3T in radial imaging planes. Our sequence was validated in a phantom and in 10 hips against a rigorous multi-point SR pulse sequence. T1 measurements by the two sequences were strongly correlated (R2 > 0.95) and in excellent agreement (mean difference = -8.7ms; ± 95% limits of agreement = 64.5 and -81.9ms, respectively). T1 measurements were insensitive to B1+ variation as large as 20%.

17:24 505.   Parametric relaxation measurements in bovine patellar cartilage 
Wen Ling1, Elizabeth Arendt2, Denis Clohisy2, Silvia Mangia1, Shalom Michaeli1, Michael Garwood1, and Jutta Elllermann1
1Center for Magnetic Resonance Research, Univ. of Minnesota, Minneapolis, MN, United States, 2Dept. of Orthopedic Surgery, Univ. of Minnesota, Minneapolis, MN, United States

Bovine patellar cartilage plugs with trypsin treatment (n=4) were used to compare various contrast mechanisms, including T2, T1ρ by adiabatic HS1 and HS4 modulation, RAFF (relaxation along a fictitious field), and MT (magnetic transfer). Each of the plugs was scanned twice: before and after trypsin treatments. The control group (n=4) were through the same process except without trypsin treatment. Our results not only depict that adiabatic T1ρ gives rise to high sensitivity to proteoglycan induced change in cartilage, but also indicate it is a robust and artifact-free method.

17:36 506.   Simultaneous acquisition of T1rho and T2 quantification in cartilage reproducibility and diurnal variation 
Xiaojuan Li1, Joseph Schooler1, Fei Liang1, Keerthi Shet Vishnudas1, Weitian Chen2, Suchandrima Banerjee2, and Sharmila Majumdar1
1Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States, 2Global Applied Science Laboratory, GE Healthcare, Menlo Park, CA

Magnetic resonance (MR) T1ρ and T2 relaxation time quantification can detect biochemical changes within cartilage collagen/proteoglycan matrix, and may provide complementary information associated with cartilage degeneration during osteoarthritis (OA). These techniques, however, normally need a long acquisition time. Furthermore, few studies have explored the potential diurnal variation in cartilage. The goals of this study were three fold: 1) To develop a sequence that combines T1ρ and T2 quantification; 2) To examine intra-day and inter-day reproducibility of the T1ρ and T2 quantification; 3) To examine the potential diurnal variation of T1ρ and T2 quantification in cartilage in young healthy adults.

17:48 507.   Are sports good for your knees? An MRI evaluation of the effects of basketball on knee health in Division I collegiate athletes 
Melissa Ann Vogelsong1,2, George Pappas3, Ernesto Staroswiecki1,4, Neal K Bangerter5, Eric Han6, Brian A Hargreaves1, Hillary J Braun1, Marc R Safran3, and Garry E Gold1
1Radiology, Stanford University, Stanford, CA, United States, 2UCSF School of Medicine, San Francisco, CA, United States, 3Orthopaedic Surgery, Stanford University,4Electrical Engineering, Stanford University, 5Electrical Engineering, Brigham Young University, 6GE Global Applied Sciences Laboratory, Menlo Park, CA

Advances in imaging of cartilage biochemistry allow a more nuanced look at the effects of exercise on articular cartilage. T2 mapping reflects collagen structure and water content, while T and sodium MRI reflect proteoglycan content. We imaged 21 knees of collegiate basketball players before and after one season and assessed knee health using conventional proton, T2 mapping, T and sodium MRI. Rates of morphological pathologies remained relatively stable while T decreased in all patellar and tibiofemoral regions, T2 increased in the medial femur, lateral femur and medial tibia, and sodium signal decreased in the patella, suggesting that basketball may have varying effects on different cartilage regions.