Room 255 BC

13:30 - 15:30

Moderators:

Christopher J. Hamrahan, Roland Krug

Timothy Mosher

 

Hans Liebl¹, Ursula Heilmeier¹, Sonia Lee¹, Lorenzo Nardo¹, Christopher Schuppert¹, Misung Han¹, Suchandrima Banerjee², Kevin Koch³, Thomas M. Link¹, and Roland Krug^1
1Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, United States, ²GE healthcare, Menlo Park, California, United States, ³GE healthcare, Milwaukee, Wisconsin, United States

3D Multi-Spectral Imaging techniques such as MAVRIC and SEMAC are currently being investigated to improve MR-imaging in the presence of metal hardware. We study the performance of MAVRIC-SL at 1.5T vs. 3T compared to standard-of-care sequences. Detection rates for cartilage and bone lesions created in the proximity of metallic hardware placed in twelve pigknee specimens were analyzed and the sizes of artifacts measured. Preliminary data analysis indicates significantly better lesion detection in MAVRIC compared to conventional sequences at both field strengths. Comparing field strenghts, no significant differences were found in lesion detection, but artifact sizes were measured larger at 3T.

Gerd Melkus¹, Michelle Grabau¹, Dimitrios C. Karampinos^1,2, and Sharmila Majumdar^1
1Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, United States, ²Diagnostic and Interventional Radiology, Technical University of Munich, Munich, Bavaria, Germany

Studies have linked low pH and loss of glycoaminoglycan in the intervertebral disc of patients with discogenic back pain. Therefore MRI methods to measure pH in intervertebral discs would be valuable in research and clinical settings. The present study performed on phantoms and porcine discs investigates if gagCEST shows pH dependence and if this effect could be used to detect pH changes in the discs. Further, the DIACEST agent Iopromide is injected into the disc specimens to investigate if CEST MRI can be used to detect intervertebral disc pH using this molecule.

Yongxian Qian¹, Jinbai Huang¹, Vincent K. Lee¹, and Fernando Emilio Boada^2
1Radiology, University of Pittsburgh, Pittsburgh, PA, United States, ²Radiology, New York University, New York, NY, United States

A major challenge to two-component T2* mapping on cartilages in human knee at pixel level is the instability of mapping for the short-T2* component due to insufficient signal-to-noise ratio (SNR) available in clinical setting. A large number of TE acquisitions was proposed in this work to mitigate the demanding of high SNR and stabilize the mapping of short-T2* relaxation. The technical feasibility of this idea was successfully tested in this study.

Emily J. McWalter¹, Garry E. Gold¹, Marcus T. Alley¹, and Brian Andrew Hargreaves^1
1Radiology, Stanford University, Stanford, California, United States

T₂ and T₂* relaxation time mapping can be used to detect early degeneration of the meniscus; however, current techniques require lengthy scans (10 to 20 minutes per measure). We present a novel, rapid multi-echo steady state technique to simultaneously estimate T₂ and T₂* relaxation times in the meniscus in under 5 minutes. The relaxation times estimated using this new technique agreed well with standard measures and were obtained in a fraction of the time.

Chan Hong Moon¹, Jung-Hwan Kim¹, Tiejun Zhao², and Kyongtae Ty Bae^1
1Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States, ²MR R&D Collaborations, Siemens Healthcare, Pittsburgh, Pennsylvania, United States

We developed a new high-sensitivity multi-channel ²³Na RF coil for knee MRI at 7T. Our ¹H/²³Na MRI allowed quantitative measurement of [²³Na] in knee cartilage by taking into consideration of the ²³Na imaging point spread function and ¹H imaging cartilage thickness.

Vladimir Juras^1,2, Sebastian Apprich¹, Pavol Szomolanyi¹, Oliver Bieri³, Xeni Deligianni³, and Siegfried Trattnig^1
1MR Centre of Excellence, Department of Radiology, Medical University of Vienna, Vienna, Austria, ²Department of Imaging Methods, Institute of Measurement Science, Bratislava, Slovakia,³Department of Radiology, Division of Radiological Physics, University of Basel Hospital, Basel, Switzerland

Mono-exponential curve-fitting for T2* calculation in AT can lead to misinterpretation of the results. The suggested algorithm for bi-exponential T2* fitting enables T2* to be a robust parameter that correlates with the actual clinical condition of the patient's tendon. T2* short may be a predictive marker for the probability of an AT rupture, as well as for a re-rupture after surgery. Bi-exponential fitting, although it is computationally more demanding, is also more precise and also allows distinguishing between bound and free water molecules.

William D. Rooney¹, Sean C. Forbes², William Triplett³, D-J Wang⁴, James Pollaro¹, Soren DeVos², Rebecca J. Willcocks³, Richard Finkel⁵, Barry Russman⁶, Barry Byrne⁷, Lee Sweeney⁸, Glenn A. Walter³, and Krista Vandenborne^2
1Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR, United States, ²Department of Physical Therapy, University of Florida, Gainesville, FL, United States,³Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL, United States, ⁴Radiology, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States,⁵Neurology, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States, ⁶Neurology, Oregon Health & Science University, Portland, OR, United States, ⁷Department of Pediatrics, University of Florida, Gainesville, FL, United States, ⁸Department of Physiology, University of Pennsylvania, Philadelphia, PA, United States

The purpose of the study was to investigate the age dependence of MRS water proton qT2 values in healthy control boys and boys with DMD. Data were acquired from 83 DMD boys and 22 healthy controls on 3T MRI instruments at three institutions. 1H MRS data were acquired to estimate 1H2O T2 using a STEAM single voxel located in the soleus muscle. 1H2O T2 values were significantly increased for DMD boys and decreased with age. Corticosteroid treated DMD boys had a lower 1H2O T2 than untreated DMD boys.

Steven Baete¹, Gene Cho^1,2, and Eric E. Sigmund^1
1Center for Biomedical Imaging, Dept. of Radiology, NYU Langone Medical Center, New York, NY, United States, ²Sackler Institute of Graduate Biomedical Sciences, NYU School of Medicine, New York, NY, United States

Dynamic single voxel acquisition of diffusion tensor parameters is demonstrated in an anisotropic phantom and in in vivo skeletal muscle on a 3T clinical scanner. This method, Single Voxel Multiple Echo Diffusion Tensor Acquisition Technique (SV-MEDITATE) encodes multiple echoes generated by five RF-pulses with each a different diffusion weighting and strength. A single voxel is selected by orthogonal slice selective gradients. The resulting single voxel dynamic acquisition can be used to study the transient changes in diffusion tensor parameters, such as in muscle tissue following exercise, where traditional DTI methods lack temporal resolution.

Christopher D.J. Sinclair^1,2, Jasper M. Morrow¹, Robert L. Janiczek³, Michael G. Hanna¹, Mary M. Reilly¹, Tarek A. Yousry^1,2, Rebecca S. Samson⁴, Nikolaus Weiskopf⁵, Antoine Lutti⁵, David L. Thomas², Xavier Golay⁶, and John S. Thornton^1,2
1MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, London, United Kingdom, ²Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London, London, United Kingdom, ³United Kingdom, GlaxoSmithKline, Brentford, Middlesex, United Kingdom, ⁴Department of Neuroinflammation, UCL Institute of Neurology, London, London, United Kingdom, ⁵Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, London, London, United Kingdom, ⁶Department of Brain Repair and Rehabilitation, University College London, London, London, United Kingdom

Quantitative imaging of skeletal muscle may provide important markers of disease for clinical trials. We used quantitative magnetization transfer (qMT) imaging and the IDEAL-CPMG fat-water separation method to quantify the muscle water-component T2 relaxation times and muscle fat-fraction in the calves of patients with inclusion body myositis. A range of pathologies were observed including isolated T2 elevation, isolated fat-fraction increases or both. QMT parameters, such as the bound pool fraction f, reflected the variations and f was decreased in muscle displaying isolated edema. Further investigation of these relationships may allow the identification of muscles involved early in the disease.