Hiroyuki Takashima^1,2, Tsuneo Takebayashi³, Yasuhisa Abe³, Rui Imamura¹, Hiroshi Oguma³, Izaya Ogon², Yoshihiro Akatsuka¹, and Toshihiko Yamashita^2
1Division of Radiology and Nuclear Medicine, Sapporo Medical University Hospital, Sapporo, Japan, ²Department of Orthopaedic Surgery, Sapporo Medical University School of Medicine, Sapporo, Japan, ³Department of Orthopaedic Surgery, Sapporo Maruyama Orthopedic Hospital, Sapporo, Japan

Previous studies have reported that the disorder of intramedullary perfusion in the vertebral fracture (VF) delays the bone union process. However, few reports evaluating VF using intravoxel incoherent motion (IVIM) exist. The IVIM parameters between favorable and unfavorable VF prognosis were compared, and we investigated whether possible to evaluate for the VF prognosis. ADC, D, D*, and f in VF as IVIM parameters were measured, and the IVIM parameters between the favorable and unfavorable prognosis groups was compared. The IVIM parameters were significantly different between groups. Therefore, it is concluded that the IVIM analysis enables the prediction of VF prognosis.

Seung Eun Lee¹, Joon-Yong Jung¹, and Dongyeob Han^2
1Seoul St. Mary’s Hospital, Seoul, Korea, Republic of, ²Siemens Healthineers, Seoul, Korea, Republic of

The morphologic MR imaging is limited in identifying sub-voxel sized cartilage defect due to partial volume averaging. We assessed the feasibility of synovial fluid fraction (SFF) map generated by multicomponent approach using MRF-derived relaxation maps to characterize sub-voxel sized cartilage defect. In ex vivo experiment, we proved that SFF map can quantify synovial fluid fraction in sub-voxel sized cartilage defects. In clinical study, we demonstrated that SFF map can complement morphologic imaging in cartilage segmentation and volumetric assessment.

Iman Khodarahmi¹, Inge Manuela Brinkmann², Dana Lin¹, Mary Bruno¹, Patricia Johnson¹, Florian Knoll¹, Mahesh Bharath Keerthivasan², Hersh Chandarana¹, and Jan Fritz^1
1Department of Radiology, New York University School of Medicine, New York, NY, United States, ²Siemens Medical Solutions USA Inc., Malvern, PA, United States

Next-generation, advanced low-field MRI holds promise to improve metal artifact reduction MRI of hip arthroplasty implants due to inherently lower susceptibility effects. Using titanium-on-ceramic and metal-on-metal cobalt-chromium total hip arthroplasty implant phantoms, we compared the degree of metal artifacts and signal-to-noise ratios of MR images obtained with modified 0.55T prototype and clinical 1.5T MRI systems. The 0.55T SEMAC MR images with 6-9 encoding steps invariably demonstrated superior, near-complete metal artifact reduction. Our preliminary results suggest clinically viable sequence acquisition times of ≤ 6-min with advanced 0.55T MRI.

Cihat Eldeniz¹, Udayabhanu Jammalamadaka¹, Gary B. Skolnick², Paul K. Commean¹, Kamlesh B. Patel², and Hongyu An^1
1Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, MO, United States, ²Division of Plastic and Reconstructive Surgery, Washington University in St. Louis, St. Louis, MO, United States

Computed tomography (CT) is the reference method for skull imaging, but can cause cancer due to ionizing radiation. Magnetic resonance imaging (MRI) is safer, but the prolonged scan time increases the chance of motion, especially for pediatric patients. Sedation helps reduce motion significantly, but is associated with risks. A sedation-free MRI scheme that is robust to motion is therefore highly desirable. Here, we proposed such a method by making use of a radial acquisition scheme that is inherently robust to motion. The robustness was further boosted by a forward-modeled motion-corrected reconstruction. The results show the promise of the method.

Kevin Matthew Koch¹, Mohammad Zarenia², V. Emre Arpinar², L Tugan Muftuler³, Alyssa Joy Schnorenberg ⁴, Joshua Leonardis⁴, Brooke Slavens⁴, and Andrew S Nencka^2
1Medical College of Wisconsin, Milwaukee, WI, United States, ²Radiology, Medical College of Wisconsin, Milwaukee, WI, United States, ³Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, United States, ⁴University of Wisconsin, Milwaukee, Milwaukee, WI, United States

A unique approach to analysis of wrist mechanics is analyzed.  In this approach, 4D dynamic MRI is utilized to track unconstrained movement of individual wrist carpal bones.   Through a boundary-based slab-to-volume registration approach, fiducial points identified or computed on high resolution static images are tracked using the dynamic time series to generate time-domain signals indicative of independent and relative carpal bone movement.  After rudimentary processing of 12  derived signals, each computed on 3 asymptomatic control subjects, correlation analysis is utilized to elucidate the utility of these metrics in establishing a normative kinematic profile of the healthy wrist. 

Preety Krishnan¹, Tejas J Shah², Akshay Godkhindi², Rupsa Bhattacharjee³, Stanley Kovil Pichai³, Ajay Krishnan¹, Bharat Dave¹, and Indrajit Saha^3
1Stavya Spine Research Institute, Ahmedabad, India, ²MR, Philips Innovation Campus, Bangalore, India, ³Philips India Limited, Gurgaon, India

Given the prevalence and disease burden of osteoporosis, it is critical to detect it as early as possible. This is challenging not only because the disease is typically asymptomatic but also due to known limitations of the gold standard method of DEXA. The aim of this study was to determine if alternative approach of 2D texture analysis in L1-L5 lumbar spine on T1W images can be used to detect osteoporosis. It is demonstrated that such an approach can indeed be used to clinically detect osteoporosis with an AUC of 0.8. 

Benedikt Hager^1,2,3, Markus M. Schreiner⁴, Sonja M. Walzer⁴, Lena Hirtler⁵, Vladimir Mlynarik¹, Martin Zalaudek¹, Andreas Berg⁶, Xeni Deligianni^7,8, Oliver Bieri^7,8, Reinhard Windhager⁴, Vladimir Juras¹, and Siegfried Trattnig^1
1Department of Biomedical Imaging and Image-guided Therapy, High Field MR Centre, Medical University of Vienna, Vienna, Austria, ²CD Laboratory for Clinical Molecular MR Imaging, Vienna, Austria, ³Austrian Cluster for Tissue Regeneration, Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, Vienna, Austria, ⁴Department of Orthopedics and Trauma-Surgery, Medical University of Vienna, Vienna, Austria, ⁵Center for Anatomy and Cell Biology, Division of Anatomy, Medical University of Vienna, Vienna, Austria, ⁶Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria, ⁷Division of Radiological Physics, Department of Radiology, University of Basel Hospital, Basel, Switzerland, ⁸Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland

In this study, we analyzed the T₂* anisotropy and mono- vs. bi-exponentiality of T₂* decay of Achilles and patellar tendons in vitro with a variable echo time sequence, ultrashort echo times and microscopic resolution and compared the results with histological findings. A total of four human Achilles tendons and four patellar tendons were measured at their maximum and minimum dipolar interaction (0°, 55°). In addition, one Achilles tendon and one patellar tendon were measured at  11 fiber-to-field angles (0,10,20,30,40,50,60,70,80,90°) each in order to study the change in T₂* values at these angles.

Brandon Clinton Jones^1,2, Hyunyeol Lee¹, Shaowei Jia^1,3, Anna Feng¹, Snehal S Shetye⁴, Hee Kwon Song¹, Felix Werner Wehrli¹, and Chamith Sudesh Rajapakse^1,4
1Radiology, University of Pennsylvania, Philadelphia, PA, United States, ²Bioengineering, University of Pennsylvania, Philadelphia, PA, United States, ³Biomedical Science and Medical Engineering, Beihang University, Beijing, China, ⁴Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, United States

UTE measures of cortical bone water were evaluated in 15 cadaveric proximal femora. Pore water content, total water content, and porosity index were all negatively associated with whole-bone stiffness obtained in a sideways fall loading configuration and with volumetric bone mineral density. In contrast, bound water content was not found to be related to stiffness or mineral density. This data suggest that bone water measures may provide useful information on cortical bone mechanical competence.

Sophia Kronthaler¹, Christof Boehm¹, Peter Börnert², Ulrich Katscher², Kilian Weiss³, Marcus R. Makowski¹, Benedikt J. Schwaiger¹, Alexandra S. Gersing¹, and Dimitrios C. Karampinos^1
1Department of Diagnostic and Interventional Radiology, School of Medicine, Technical University of Munich, Munich, Germany, ²Philips Research Laboratory, Hamburg, Germany, ³Philips Healthcare, Hamburg, Germany

CT and MR imaging are often both performed in patients with vertebral fractures or degenerative changes, with CT aiming at the characterization of osseous changes and the MR focusing on bone marrow edema. CT is associated with radiation exposure and therefore it is desirable to assess both soft-tissue and osseous components in one MR examination. The present work develops a methodology for simultaneously extracting susceptibility weighted imaging (SWI) and single point Dixon imaging based on a single-TE ultrashort echo time (UTE) scan to simultaneously assess vertebral fractures and degenerative bone changes in the thoracolumbar spine with a single MR sequence.

Wenzhao Yuan¹, Yiwu Lei¹, Cheng Tang¹, Fang Qin¹, Jing Wen¹, Chenhui Li², Min Ling¹, Jiang Huang¹, Huiting Zhang³, and Liling Long^1
1The First Affiliated Hospital of Guangxi Medical University, Nanning, China, ²Siemens Healthcare Ltd., Guangzhou, China, ³Siemens Healthcare Ltd., Wuhan, China

The purpose of this study was to determine whether high-speed T2-corrected multiecho (HISTO) sequences can quantify bone marrow edema (BME) in the capitate bone in rheumatoid arthritis (RA), and whether the HISTO fat fraction (FF) reflects therapeutic effectiveness.

The results showed that the HISTO sequence can measure the bone marrow FF of the wrist joint in RA patients. We also found that the HISTO sequence may help quantify BME in RA and help monitor the effectiveness of RA treatment.