Rachel A High^1,2, Yang Ji¹, Ya-Jun Ma¹, Qingbo Tang², Mark E Murphy³, Jiang Du¹, and Eric Y Chang^1,2
1Radiology, University of California San Diego, San Diego, CA, United States, ²Radiology Service, VA San Diego Healthcare System, San Diego, CA, United States, ³Orthopedic Surgery Service, VA San Diego Healthcare System, San Diego, CA, United States

The acidification of musculoskeletal tissues is being investigated as a way to localize pain in osteoarthritis. AcidoCEST-UTE MRI can measure pH in tissues such as cartilage and meniscus, though in vivo validation is difficult. Thus, it is imperative that the acidoCEST-UTE sequence be reproducible and verifiable ex vivo, where pH measurements can be confirmed with a pH electrode. This study tested the reproducibility of the acidoCEST-UTE sequence in three ex vivo phantoms, confirming the pH sensitivity of the technique and demonstrating the consistency of the method and results.

Xing Lu^1,2, Chang Guo¹, Kai Zheng¹, Dashan Gao², Yunqiang Chen², Haimei Chen¹, and Yinghua Zhao^1
1Department of Radiology, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China, ²12Sigma Technologies, San Diego, CA, United States

Artificial intelligence for interpreting MRI meniscal tear could prioritize high risk patients and assist clinicians in making diagnoses. In this study, a two-stage end-to-end convolutional neural network, with Mask rcnn as backbone for object detecting and Resnet for classification, is proposed for automatically detecting torn in the meniscus on MRI exams. With training dataset of 507 MR images and validation dataset of 69 MR images, the meniscus detection achieves a recall of 0.95 when 1 false positive of 1 image, and the ROC for classification of torn meniscus get a AUC of 0.99.

Nian Wang¹, Gary Cofer¹, Louis E. DeFrate², Abigail Holt², Amy L. McNulty², Yi Qi¹, Charles E. Spritzer¹, and G. Allan Johnson^1
1Department of Radiology, Duke University, Durham, NC, United States, ²Department of Orthopaedic Surgery, Duke University, Durham, NC, United States

Application of diffusion magnetic resonance imaging (dMRI) to map the complex collagen fibril structures of meniscus is still challenging, due to the short T2/T2* values, low fractional anisotropy (FA) values, and relatively low signal-to-noise (SNR). In this study, we imaged the porcine menisci in a preclinical 7 T system with relatively short echo time (TE ~ 11 ms). A 3D diffusion-weighted spin-echo pulse sequence was used for whole meniscus tractography at 125 µm isotropic resolution. 

Venkata Veerendranadh Chebrolu^1,2, Peter Kollasch^1,2, Eric G Stinson^1,2, Andrew J Fagan², Joel P Felmlee², Benjamin M Howe², Matthew A Frick², and Kimberly K Amrami^2
1Siemens Medical Solutions USA, Inc., Rochester, MN, United States, ²Department of Radiology, Mayo Clinic, Rochester, MN, United States

In this work, we propose the use of Subtle Intensity Graduating Homomorphic Transform (SIGHT) along with application of a small percentage of fat-saturation (fat-sat) to improve the conspicuity of meniscal tears at 7T. 2 musculoskeletal radiologists compared turbo-spin-echo (TSE) proton-density (PD)-weighted knee MRI (without fat-sat) with 12 different MRI options (TE, TR, fat-sat, field-of-view, and image-processing variations) for conspicuity of meniscal tears and rated 1^st, 2^nd and 3^rd preferred options for each case. SIGHT image-processing applied to PD-weighted MRI along with a small percentage of fat-sat provided better conspicuity of meniscal tears than the regular PD- and T2-weighted MRI images.

Karyn Elizabeth Chappell¹, Mihailo Ristic², Donald McRobbie³, Wladyslaw Gedroyc⁴, Djordje Brujic², and Catherine Van Der Straeten^5
1Medicine, Orthopaedic Surgery, Stanford University, Redwood City, CA, United States, ²Mechanical Engineering, Imperial College London, London, United Kingdom, ³University of Adelaide, Adelaide, Australia, ⁴Imperial College London, London, United Kingdom, ⁵Imperial College London/Ghent University, Ghent, Belgium

Does freeze/thaw of cadaveric specimens’ damage collagen fibre orientation?  Magic angle directional imaging (MADI) in caprine knees assessed the underlying tissue structure before and after freezing for three and six weeks. Tendon thickness reduced after 6 weeks of freezing.  Segmented collagen containing voxels decreased by half after freezing.  Voids appeared in the internal tendon structure suggestive of ice crystal formation that disrupted collagen fibre orientation. The severity of the structural changes increased the longer the tissue was frozen. Interpreting results with frozen/thawed cadaveric specimens needs care as freezing damages collagen fibre structure that may impact on biomechanical and other properties.

Karyn Elizabeth Chappell¹, Djordje Brujic², Mihailo Ristic², Donald McRobbie³, Wladyslaw Gedroyc⁴, Catherine Van Der Straeten⁵, and Richard Meeson^6
1Medicine, Orthopaedic Surgery, Stanford University, Redwood City, CA, United States, ²Mechanical Engineering, Imperial College London, London, United Kingdom, ³University of Adelaide, Adelaide, Australia, ⁴Imperial College London, London, United Kingdom, ⁵Imperial College London/Ghent University, Ghent, Belgium, ⁶Royal Veterinary College, London, United Kingdom

A proof of concept study in a spontaneous ligament rupture dog model assessed if the magic angle effect disappears in unhealthy tissue.  Ten dogs were scanned using the MADI technique.  Standard deviation (SD) maps of signal intensity were computed and measured in an interactive display.  Three subjects showed abnormally high SD; two at the ACL origin, one in the trochlear articular cartilage.  Fibre orientation maps showed either disorganised or highly organised collagen fibres in these subjects.  On dissection two subjects had partially torn ACLs and the other a fibrocartilage lesion.  There was excellent correlation between the MADI and dissection findings. 

Saya Horiuchi^1,2, Hon Yu¹, Toshimi Tando¹, Taiki Nozaki², and Hiroshi Yoahioka^1
1Department of radiological sciences, University of California, Irvine, Irvine, CA, United States, ²Radiology Department, St. Luke's International Hospital, Tokyo, Japan

It is technically challenging to diagnose injuries to the radioulnar ligaments (RUL) of the wrist on magnetic resonance imaging (MRI). We identified and classified the morphology of the dorsal and volar radioulnar ligaments (RUL) of the wrist into five types using 3T MRI. Two hundred and nine participants were retrospectively evaluated using 3T axial 2D and reformatted axial isotropic 3D images. Both dorsal and volar RULs attach to the radial to dorsal side of the ulnar styloid. The RUL was equally identified on high-resolution two-dimensional and on isotropic three-dimensional MRI.

Mei Wu^1,2, Mingxin Chen¹, Yajun Ma¹, Akhil Kasibhatla¹, Lidi Wan¹, Saeed Jerban¹, Hyungseok Jang¹, Eric Y Chang^1,3, and Jiang Du^1
1Department of Radiology, University of California, San Diego, San Diego, CA, United States, ²Department of Radiology, Guangzhou First People’s Hospital, School of Medicine, South China University of Technology, Guangzhou, China, ³Radiology Service, VA San Diego Healthcare System, San Diego, CA, United States

This study investigated the magic angle effect in three-dimensional ultrashort echo time Cones Adiabatic T1ρ (3D UTE Cones-AdiabT1ρ) imaging of the Achilles tendon on a clinical 3T scanner. The magic angle effect was investigated by repeated UTE Cones-AdiabT1ρ imaging of five human Achilles tendon samples at five angular orientations ranging from 0° to 90° relative to the B0 field. Conventional Cones continuous wave T1ρ (Cones­-CW-T1ρ) and Cones-T2* sequences were also applied for comparison. Cones-AdiabT1ρ showed a much reduced magic angle effect as compared to regular Cones-CW-T1ρ and Cones-T2*, suggesting its potential use as a novel biomarker for musculoskeletal (MSK) imaging.

xue yu xie¹, puye wu², and shuang chen^3
1radiology, huashan hospital, shanghai, China, ²GE healthcare, beijing, China, ³huashan hospital, shanghai, China

A longitudinal  monitoring of the supraspinatus tendon healing during the first year after arthroscopic rotator cuff repair (ARCR) surgery using quantitative ultrashort echo time (UTE)-Cones.

Benedikt Hager^1,2, Markus M. Schreiner³, Vladimir Mlynarik¹, Vladimir Juras¹, Xeni Deligianni^4,5, Oliver Bieri^4,5, Reinhard Windhager³, and Siegfried Trattnig^1,2
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, ³Department of Orthopaedics and Trauma Surgery, Medical University of Vienna, Vienna, Austria, ⁴Department of Radiology, Division of Radiological Physics, University of Basel Hospital, Basel, Switzerland, ⁵Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland

In our study in which we used a variable echo-time sequence for T₂*-mapping of tendons in vivo at 3T and 7T, we showed that even small changes in the knee position in the knee coil can lead to significant changes in the T₂*-values of the patellar tendon and quadriceps tendon. We have also shown that the T₂*-values of the tendons correlate well with the angle of the bulk of the collagen fibers to the magnetic field. Based on these results, we recommend that for T₂*-mapping it is important to examine the tendon in exactly the same position in the follow-up.

Martin Krämer¹, Marta B Maggioni¹, and Jürgen R Reichenbach^1
1Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany

Segmentation of tendons based on MRI data is challenging because of their very short transverse relaxation times and typically curved structure as well as small diameter. In this work, we performed combined T₂* and T₁ mapping using multi-echo and variable flip angle ultra-short echo-time imaging. Based on the resulting relaxation parameter maps, bivariate histograms were calculated which showed distinct clusters that could be ascribed to various tissues. Ranges for both relaxation parameters were defined using these histograms and applied to volumetrically segment and subsequently visualize the patellar and quadriceps tendon.

Saeed Jerban¹, Takehito Hananouchi², Yajun Ma¹, Erik Dorthe³, behnam namiranian¹, Jonathan Wong⁴, Mei Wu¹, Darryl D'lima³, Eric Y Chang⁴, and Jiang Du^1
1Radiology, University of California, San Diego, San Diego, CA, United States, ²Department of Mechanical Engineering, Osaka Sangyo University, Daito, Osaka, Japan, ³Shiley Center for Orthopedic Research and Education at Scripps Clinic, La Jolla, CA, United States, ⁴Research Service, VA San Diego Healthcare System, San Diego, CA, United States

Clinical MRI techniques typically show the anterior cruciate ligament (ACL) as low in signal. Commonly used quantitative MRI techniques are sensitive to tissue orientation and magic angle effect. A recently developed ultrashort echo time (UTE)-based adiabatic T1ρ technique (UTE-Ad-T1ρ) can detect high signal in the ACL and may be less sensitive to magic angle effect. We have investigated for the first time the correlation between UTE-Ad-T1ρ and ACL mechanical properties. T1ρ showed significant strong correlation with average elastic modulus of ACL specimens. The UTE-Ad-T1ρ technique is highlighted as a potential tool to noninvasively assess the ACL mechanical properties.

Erin C Argentieri¹, James C Yoder¹, Garry Gold², Sharmila Majumdar³, Matthew F Koff¹, and Hollis G Potter^1
1Radiology and Imaging, Hospital for Special Surgery, New York, NY, United States, ²Stanford University, Stanford, CA, United States, ³University of California San Francisco, San Francisco, CA, United States

As basketball players represent a population with an inherently high risk of sustaining meniscal injuries, studying how basketball play can lead to changes in the meniscus is of clinical importance. To date, no studies have been performed to evaluate T2* values of the meniscus in high performance athletes. Therefore, the purpose of this study was to utilize ultra-short TE (UTE) MRI to compare meniscal T2* values between basketball players and swimmers. Significant differences of T2* values were found between the medial and lateral menisci. No significant difference of meniscal T2* values were found between basketball players and swimmers.

Erin C Argentieri¹, Tatum W Braun¹, Ryan E Breighner¹, Bin Q Lin², Ellen K Casey³, Shari T Jawetz¹, Alissa J Burge¹, Matthew F Koff¹, and Hollis G Potter^1
1Radiology and Imaging, Hospital for Special Surgery, New York, NY, United States, ²Biostatistics, Hospital for Special Surgery, New York, NY, United States, ³Physiatry, Hospital for Special Surgery, New York, NY, United States

This study evaluates changes in ACL T2* metrics over the course of the female menstrual cycle. In the pre-ovulatory phase, normally ovulating case subjects demonstrated significant shortening of T2*S and PS in comparison to visit #4 (post-ovulatory phase). Non-ovulatory control subjects displayed no significant changes over time. These findings suggest that shifts in collagen bound water occur within the ACL over the course of the menstrual cycle. Shifts in tissue water content have been associated with altered mechanical properties, and changes in ligament stiffness may alter proprioceptive sense, contribute to increases in laxity, and alter ACL-injury risk.

Hui Hao¹, Jia Yin Tong¹, Xiao Cheng Wei², and Jian Yang^1
1Department of Radiology, the First Affiliated Hospital, Xi'an Jiaotong University, xi'an, China, ²MR Research China, GE Healthcare, Bei Jing, China

The increase of multifidus muscle fat infiltration will affect the postoperative rehabilitation of patients with lumbar spine surgery. In this study, reasons for fat infiltration on both sides of multifidus muscles were analyzed retrospectively. Through Priffman grading evaluating the intervertebral disc and Kader grading for fat infiltration, a retrospective analysis was conducted on 453 cases of intervertebral discs images. In our study, nerve root compression was found to be correlated with degree of multifidus muscle fat infiltration. This correlation support the hyposis that nerve root compression would result in an increase in the adiposity of multifarious muscles.

Nick Zafeiropoulos¹, Stephen Wastling¹, Jasper Morrow², Uros Klickovic¹, Pietro Fratta¹, Sachet Shah¹, Enrico De Vita³, Mary M Reilly², Tarek Yousry¹, and John Thornton^1
1UCL Queen Square Institute of Neurology, London, United Kingdom, ²MRC Centre for Neuromuscular Diseases, London, United Kingdom, ³King's College London, London, United Kingdom

In vivo lower-limb STIR images were compared with images simulated using a theoretical signal model with experimentally determined muscle-water T₂ and fat fraction values. Nominally  T₂-weighted STIR contrast is seen to depend on changing tissue-water relative proton density as fat content increases in diseased muscle, in addition to expected T₂ dependent changes. Imperfect inversion-recovery fat nulling may also cause unexpected hyper-intensity in regions of high fat content. These observations may have implications for the clinical interpretation of STIR signal intensity.  

Alfredo Liubomir Lopez Kolkovsky^1,2, Benjamin Marty^1,2, Marc Lapert³, Eric Giacomini¹, and Pierre G Carlier^1,2
1NMR Laboratory, Institute of Myology, Paris, France, ²NMR Laboratory, CEA/DRF/IBFJ/MIRCen, Paris, France, ³Siemens Healthcare SAS, Saint-Denis, France

Interleaving multinuclear NMR measurements in the muscle during a transient state enriches the value of the exam by generating multiple data sets simultaneously. Here we show the results of our multinuclear interleaved approach using a ¹H/³¹P dual-tune RF coil dedicated for calf experiments during an exercise and an ischemia-hyperemia paradigm. The nuclear Overhauser enhancement effect, which is dependent on the sequence and RF design, is characterized and its impact on rephosphorylation rate estimation and the [Pi]/[PCr] ratio is evaluated. The proposed methodology constitutes a powerful tool to evaluate mitochondrial function and metabolic efficiency in vivo.

YueFen Zou¹, Yu Zheng¹, HongYuan Ding¹, SiSeung Kim², Shekhar Suresh Chandra³, Jurgen Fripp⁴, Jian Bao², HuiYao Zhang², Bing Keong Li², and Craig Engstrom ^5
1Medical Imaging, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China, ²Jiangsu LiCi Medical Device Co. Ltd, LianYunGang, China, ³ITEE, The University of Queensland, Brisbane, Australia, ⁴The Australian e-Health Research Centre, CSIRO, Brisbane, Australia, ⁵School of Human Movement & Nutrition Science, The University of Queensland, Brisbane, Australia

Standing weight-bearing MR images of the knee joint in full extension and at various flexion angles (~15°, 30°) were acquired using 2D and 3D sequences on a newly developed open 0.25T extremity MRI system. 3D FLASH images were used to calculate measures of patella positioning used in previous clinical investigations as well as to produce MRI-based 3D bone models. The use of MRI and 3D modeling for topographical analyses of the bones and soft-tissues of the knee joint have the potential to provide more detailed assessment of pathoanatomical conditions involving structures such as the patella tendon and the menisci.

Martin Krämer¹, Matthias R Kollert^2,3, Nicholas M Brisson², Marta B Maggioni¹, Georg N Duda^2,3, and Jürgen R Reichenbach^1
1Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany, ²Julius Wolff Institute and Center for Musculoskeletal Surgery, Charité – Universitätsmedizin Berlin, Berlin, Germany, ³Berlin-Brandenburg Center and School for Regenerative Therapies, Charité – Universitätsmedizin Berlin, Berlin, Germany

Controlling tissue integrity and hydration levels is a crucial step when preparing and measuring ex vivo samples of tendons. In this work, we immersed ex vivo Achilles tendons in phosphate buffered saline solution and measured T₁ and T^₂* relaxation times at baseline, 30 h and 67 h after immersion using 3D ultra-short echo-time imaging with variable flip angles and echo-train shifted multi-echo acquisition, respectively. Results based on regions-of-interest in mid-tendon and enthesis areas showed a significant increase in both T₁ and T₂* after 30 h of immersion in the phosphate buffered saline solution.

Marta Brigid Maggioni¹, Martin Krämer¹, and Jürgen R. Reichenbach^1,2,3,4
1Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital - Friedrich Schiller University, Jena, Germany, ²Michael Stifel Center for Data-driven and Simulation Science Jena, Friedrich Schiller University, Jena, Germany, ³Abbe School of Photonics, Friedrich Schiller University, Jena, Germany, ⁴Center of Medical Optics and Photonics, Friedrich Schiller University, Jena, Germany

Tendons are highly ordered tissues, mainly composed of collagen, and characterized by very short transverse T₂^* relaxation times. Even when using ultra-short echo-time imaging sequences, quantification of T₂^* is challenging as the origin and characteristics of the signal decay in tendons is still under debate. In this work, we finely sampled the decay of the transverse magnetization using an echo-train shifted multi-echo ultra-short echo-time sequence with 55 echoes and applied a complex tri-exponential model to extract T₂^* constants.

Yanjun Chen^1,2, Zhenyu Cai², Liang Li², Carolyn Xie², Michael Carl³, Eric Y Chang⁴, Jiang Du², and Yajun Ma^2
1The Third Affiliated Hospital of Southern Medical University, Guangzhou, China, ²UC San Diego, San Diego, CA, United States, ³GE healthcare, San Diego, CA, United States, ⁴VA health system, San Diego, CA, United States

Strong fat signal contamination leads to significant errors in quantitative UTE (qUTE) imaging of musculoskeletal tissue. In this study, we used a fat suppression technique to investigate whether fat signals could be sufficiently suppressed in qUTE imaging and whether the fat saturation preparation would affect the resultant qUTE measures due to the induced water attenuation.

Olli Nykänen¹, Nina Hänninen^1,2, and Mikko J Nissi^1,2
1Department of Applied Physics, University of Eastern Finland, Kuopio, Finland, ²Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland

Typical measurement protocols for quantitative MRI of ex vivo osteochondral samples may last hours when multiple parameters with high resolution are measured. However, knowledge about the changes in the relaxation properties of articular cartilage during long scans is inadequate. In this study, we measured T1, adiabatic T1rho and T2-relaxation times for two osteochondral samples directly after sample preparation and repeated the measurements after 15 hours of storage at room temperature. T1-relaxation time decreased noticeably at later timepoint while adiabatic T1rho and T2-relaxation times remained the same. Due to small sample size, statistical significance of the results could not be verified.

Jeehun Kim^1,2, Wanyong Shin^2,3, Mei Li^1,2, and Xiaojuan Li^1,2,3
1Biomedical Engineering, Cleveland Clinic, Cleveland, OH, United States, ²Program of Advanced Musculoskeletal Imaging (PAMI), Cleveland Clinic, Cleveland, OH, United States, ³Department of Diagnostic Radiology, Cleveland Clinic, Cleveland, OH, United States

To fully utilize the superior signal-to-noise ratio of 7T MRI for cartilage T_1ρ imaging, high specific-absorption ratio (SAR) needs to be accounted for. Previous researches showed the use of high dielectric pad could substantially decrease the SAR in 7T MRI. In this work, the effect of the use of high dielectric pad on T_1ρ imaging in terms of SAR level and T_1ρ relaxation time quantification.

Nian Wang¹, Anthony J. Mirando², Gary Cofer¹, Yi Qi¹, Matthew J. Hilton², and G. Allan Johnson^1
1Department of Radiology, Duke University, Durham, NC, United States, ²Department of Orthopaedic Surgery, Duke University, Durham, NC, United States

Using high-order diffusion tractography to map the complex collagen fibril structures in knee joint is still challenging, due to the limited spatial resolution, low angular resolution, and low signal-to-noise (SNR). The complex fiber distributions in different connective tissues in knee joint were investigated using high resolution diffusion imaging.

Xiaoqing Liang¹, Ruyi Xie¹, Yitong Li¹, Bowen Hou¹, Weiyin Vivian Liu², and Xiaoming Li^1
1Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China, ²MR Research,GE Healthcare, Beijing, China

       Low back pain (LBP) is a common spinal disease during the middle-to-old-aged population. Degeneration of lumbar intervertebral discs (IVDs) is recognized as the common and crucial cause of LBP. Histogram analysis is a recently popular method for assessing microstructural heterogeneity, however, its diagnostic performance in intervertebral disc degeneration hasn’t been proved. Histogram analysis on axial T2* mapping was applied to characterize degenerative degrees and heterogeneity of discs. All histogram parameters of T2* value were significantly related to Pfirrmann grading. Our study confirmed that the apparent “red zone” on T2* color maps was clearly related to degeneration.

Feifei Zeng¹, Yunfei Zha², and Weiyin Liu^3
1Radiology, Renmin Hospital of Wuhan University, Wuhan, China, ²Renmin Hospital of Wuhan University, Wuhan, China, ³MR Research, GE Healthcare, Bejing, China

The purpose of this study is to compare the diagnostic value of diffusion kurtosis imaging (DKI) and intravoxel incoherent motion(IVIM) in assessing lumbar intervertebral disc degeneration. DKI parameters ( MK, MD, and FA), and IVIM parameters (ADC_standard, ADC_slow, ADC_fast, and f) of nucleus pulposus (NP), anterior annulus fibrosus (AAF) and posterior annulus fibrosus (PAF) were measured and correlated with Pfirrmann grades. It was found that DKI and IVIM parameters had significantly correlation with Pfirrmann grades. In addition, DKI was more sensitive than IVIM in quantitative detection of early lumbar intervertebral disc degeneration.

Yen-Chang Chen¹, Chien-Yuan Lin¹, Ching-Wei Gu², Yu-Hsin Tang², Wei-Min Hung², Yi-Chih Hsu², and Guo-Shu Huang^2
1GE Healthcare, Taipei, Taiwan, ²Department of Radiology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan

The cartilage endplate (CEP) plays an important role in the function and homeostasis of the intervertebral disc by serving as a mechanical stabilizer as well as a pathway for nutrient transport. There is a very little known about CEP due in part to the lack of suitable imaging technique to evaluate the CEP. The purposes of this study were to optimize the parameters of zero echo time (ZTE) MRI in enhancing CEP structure and then to evaluate the morphology of CEP in lumbar spine with herniation of disc using ZTE-MRI.

Kilian Stumpf¹, Patrick Metze¹, Tobias Speidel¹, Thomas Hüfken¹, and Volker Rasche^1
1Department of Internal Medicine II, University Medical Center Ulm, Ulm, Germany

Disorders of the temporomandibular joint (TMJ), such as pain and blockage, usually arise while the joint is in motion. Capturing this dynamic process requires high temporal resolutions and good contrast between condyle and articular disk, which is possible with advanced sequences that often need sophisticated reconstruction algorithms. In this contribution, the widely available or easily implemented and reconstructed TSE-Zoom sequence was compared to advanced radial and spiral sequences employing uniform and tiny golden angle(tyGA) profile ordering. While tyGA sequences allow fluid rendering of the joint motion, TSE-Zoom can be considered a viable alternative with excellent contrast between condyle and disk.

Joanna Lind Langner¹, Marianne Black¹, James MacKay², Kimberly Hall³, Marc Safran³, Feliks Kogan¹, and Garry Gold^1
1Radiology, Stanford University, Stanford, CA, United States, ²Cambridge University, Cambridge, United Kingdom, ³Stanford University, Stanford, CA, United States

Femoroacetabular impingement (FAI) is a disorder that causes hip pain and disability in young patients, particularly athletes. Treading water leads to increased stress on the hip, the effects of which are poorly understood. In this study, we used MRI to identify the prevalence of FAI anatomy in elite aquatic athletes that tread water. The prevalence of cam FAI was higher than that previously reported for any other sport. This study demonstrates that synchronized swimmers and water polo athletes are at increased risk of cam FAI, more than other sports.

Enrico Soldati¹, Martine Pithioux², David Bendahan³, and Jerome Vicente^1
1IUSTI, AixMarseille, Marseille, France, ²ISM, AixMarseille, Marseille, France, ³CRMBM, AixMarseille, Marseille, France

It has been previously suggested that trabecular bone could be assessed using ultra-high and high-field MRI. In the present study, human femurs head were scanned using with MRI at 3T and 7T MRI and the corresponding metrics were compared to those obtained using high resolution X-ray micro tomography.  

Feliks Kogan¹, Scott Uhlrich², Madeleine Berkson³, Akshay Chaudhari¹, Marianne Black¹, Valentina Mazzoli¹, Lauren Watkins¹, Garry E Gold¹, and Brian Hargreaves^1
1Department of Radiology, Stanford University, Stanford, CA, United States, ²Department of Mechanical Engineering, Stanford University, Stanford, CA, United States, ³Palo Alto Veterans Affairs Hospital, Palo Alto, CA, United States

Varus and valgus alignment are associated with the presence and progression of knee osteoarthritis. We assessed the feasibility of rapidly assessing leg alignment with a non-weight bearing MRI in under a minute.  Good agreement was observed between alignment measurements from MRI and weight-bearing radiographs. This technique offers a sub-one-minute scan that can be incorporated into routine MRI knee scans to add important knee alignment information and potentially removes the need for additional scanning.

Mariam Taha^1,2, Greg O. Cron^1,3,4, Gerd Melkus^3,4, Peder E.Z. Larson⁵, Mazen Ibrahim², Adam D.M. Paish^6,7, Yusra Al Mosuli^1,2, William Hadden², David Holdsworth^6,7, and Hesham Abdelbary^2
1Ottawa Hospital Research Institute, Ottawa, ON, Canada, ²Orthopedic Surgery, The Ottawa Hospital, Ottawa, ON, Canada, ³Medical Imaging, The Ottawa Hospital, Ottawa, ON, Canada, ⁴Radiology, University of Ottawa, Ottawa, ON, Canada, ⁵Radiology, University of California at San Francisco, San Francisco, CA, United States, ⁶Western University, London, ON, Canada, ⁷Robarts Research Institute, London, ON, Canada

Two to fourteen percent of primary total joint replacement cases develop periprosthetic joint infection (PJI), a devastating complication.  PJI animal models for hip and knee are required to evaluate prevention and treatment methods.  We developed a novel rat model for PJI using a 3D printed titanium hip implant. Implant stability in the rats was monitored with 7T MRI using Ultrashort Echo Time (UTE) imaging and classical spin echo imaging. UTE demonstrated superior image quality compared to spin echo imaging. This rat model will provide a unique opportunity to validate and study strategies focusing on the prevention and treatment of PJI.

Tianyang Gao¹, Shinong Pan¹, Zhao Lu¹, Fengzhe Wang¹, and Jiazheng Wang^2
1Shengjing Hospital of China Medical University, Shenyang, China, ²Clinical Science, Philips Healthcare, Beijing, China

SENSE-TSE is widely used in routine joint scanning, which requires a considerable length of scan duration. Staying in the same position for a long time inevitably causes discomfort and unwanted movement of patients, resulting in image quality degradation. Therefore, shortening imaging time to reduce motion artifacts has become an important goal in the application of CS acceleration in clinical practice.This study aims to retrospectively compare the image quality and diagnosis accuracy of CS-TSE and SENSE-TSE in lumbar vertebra MRI.

Xu Lulu¹, Qi Liang¹, Dou Weiqiang², and Shen Yong^3
1Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China, ²MR Research China, GE Healthcare, Beijing, China, ³Enhanced MR application, GE Healthcare, Beijing, China

Finding the most suitable fat-suppression technique when acquiring the images with titanium alloy, the phantom was studied. We found the STIR was most potent when comparing the other methods. This result may provide the reference value when we offer the patients with metallic hardware after surgery with the proper fat-suppression technique.

Chunye Geng¹ and Jianling Cui^1
1The Third Hospital of Hebei Medical University, Shijiazhuang, China

In BOLD-MRI studies, cuff compression was often used to establish the ischemia-reactive hyperemia model of calf muscle.We found some BOLD signals did not decrease during ischemia, but increased or stay the same.This study was to find the reasons why BOLD signal showed multiple trends in ischemic period and to optimize the ischemia model. BOLD scan was performed on volunteers under two cuff pressures.BOLD signals of all muscles showed a downward trend in the P1 model of partly reduced blood supply. However, in P2 model of blood supply blocked completely, BOLD signals had mostly gone up during ischemia ,unexpectedly.

Xiaodong Zhang^1,2, Ya-jun Ma², Aria Ashir², Mei Wu², Zhao Wei², Eric Y Chang³, and Jiang Du^2
1The third affilated hospital of Southern Medical Univerisity, Guangzhou, China, ²Department of Radiology, University of California, San Diego, CA, United States, ³Radiology Service, VA San Diego Healthcare System, San Diego, CA, United States

Magnetization transfer (MT) imaging has been used for indirect assessment of macromolecules in biological tissues. In this study, we explore the value of the 3D UTE-Cones-MT sequence for volumetric quantification of magnetization transfer ratio (MTR) and macromolecular proton fraction（f） in menisci of healthy volunteers and patients with different degrees of OA. The primary results demonstrate that this method can detect compositional changes in meniscus and can be used to differentiate healthy subjects from patients with mild or advanced OA.

HAJIME YOKOTA¹, TAKAYUKI SAKAI², MASAMI YONEYAMA³, AKIYO TAKADA⁴, and TAKASHI UNO^1
1Diagnostic Radiology and Radiation Oncology, Graduate School of Medicine, Chiba University, Chiba, Japan, ²Radiology, Eastern Chiba Medical Center, Togane, Japan, ³Philips Japan, Tokyo, Japan, ⁴Radiology, Chiba University Hospital, Chiba, Japan

MR neurography for the crus is challenging because signals of the vessels and subcutaneous edema interrupt visualization of the nerve, and the water content of the nerve is small. Phase-cycling diffusion-sensitized driven-equilibrium (pcDSDE) can reduce signals of the neighboring structures including the vesssels, and visualize the nerves with diffusion contrast. pcDSDE was better than 3D-NerveVIEW for visualizing the tibial and sural nerves in the crus. The contrast ratio between the tibial nerve and neighboring muscle was significantly higher on pcDSDE than on 3D-NerveVIEW in both the proximal and distal crura.

Ali Rashidi¹, Shivani Ahlawat¹, Rodrigo Luna¹, and Jan Fritz^1
1Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States

We investigated the exchangeability of accelerated SEMAC TSE and high-bandwidth TSE MRI in patients with spinal hardware. Two musculoskeletal radiologists found through quantitative and qualitative evaluations of 50 patients with cervical, thoracic, and lumbar spinal instrumentation that accelerated SEMAC resulted in fewer metal artifacts, better visibility of anatomical structures and abnormalities, only mildly increased blur and similar soft tissue and bone contrasts. In the spine, accelerated SEMAC TSE can be used as a replacement, rather than “add-on”, of high-bandwidth TSE. 

Deepa Thakuri¹, Puneet Bagga¹, Dushyant Kumar¹, and Ravinder Reddy^1
1Radiology, University of Pennsylvania, philadelphia, PA, United States

Nicotinamide adenine dinucleotide (NAD) plays an important role in cellular metabolism and it is important to study its correlation with other metabolites of the skeletal muscle. Phosphocreatine (PCr) present in abundant amount in the skeletal muscle facilitates the generation of ATP by conversion into creatine. 31P-MRS is a common technique used to study PCr recovery kinetics and its application has been shown in various diseases related to mitochondrial disorders. In this study, we aim to investigate the relationship between PCr recovery kinetics, total NAD concentration, and age.

Rina Ito^1,2, Junichi Hata^3,4, Mayu Iida^1,2, Fumiko Seki², Mitsuki Rikitake^1,2, Yuji Komaki², Chihoko Yamada², Daisuke Nakashima⁴, Hirotaka James Okano^3,4, and Takako Shirakawa^1
1Department of Radiology, Faculty of Health Sciences, Tokyo Metropolitan University, Tokyo, Japan, ²Live Imaging Center, Central Institute for Experimental Animals, Kanagawa, Japan, ³Jikei University School of Medicine, Tokyo, Japan, ⁴Keio University School of Medicine, Tokyo, Japan

 To analyze the disease of muscular dystrophy noninvasively, we assessed the degeneration of skeletal muscle and the distinction depending on types of muscle fibers, with changing parameters based on the sequence of diffusion weighted imaging. The mdx mice were used for longitudinal evaluation at the age from 5 to 10 weeks. We confirmed conventional diffusion tensor imaging could evaluate the pathological structure. Moreover, by applying the advanced imaging such as time-dependent diffusion MRI, we could demonstrate the functional characteristics of skeletal muscle cell and to detect micro-level condition of degeneration in mdx-mice.

Hyungseok Jang¹, Yajun Ma¹, Michael Carl², Saeed Jerban¹, Eric Chang^1,3, and Jiang Du^1
1University of California, San Diego, San Diego, CA, United States, ²GE Healthcare, La Jolla, CA, United States, ³VA San Diego Healthcare System, San Diego, CA, United States

Cartilage has a complex structure comprised of multiple zones with different MR signal properties. Among them, osteochondral junction (OCJ) cannot be directly imaged with conventional MR imaging techniques. In this study, we explore the feasibility of inversion recovery prepared fat-saturated zero echo time (IR-FS-ZTE) to image the human knee OCJ. To accentuate the signal from the OCJ region with short T2*, adiabatic inversion recovery along with fat-saturation preparation was applied, followed by continous, slient ZTE imaging. The feasibility and efficacy of IR-FS-ZTE were shown in ex vivo cadaveric human knee joints and in in vivo healthy volunteers. 

Lenka Minarikova¹, Alena Svatkova², Wolfgang Bogner¹, Siegfried Trattnig^1,3, Thomas Stulnig², and Stephan Gruber^1
1High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria, ²Clinical Division for Endocrinology and Metabolism, Department of Medicine III, Medical University of Vienna, Vienna, Austria, ³CD Laboratory for Clinical Molecular MR Imaging, Vienna, Austria

Spinal skeletal disease is one of least therapy responding symptoms in MPS patients. Cervical spine of three MPS II patients and three matched controls was measured using ²³Na MRI at 7T. There was a significant difference in intervertebral discs of MPS II patient compared to controls. ²³Na MRI represents a potential quantitative method for assessment of cervical disc degeneration in MPS II patients and could serve as a potential marker used in monitoring of emerging therapies.

Kaixuan Zhao¹, Shisi Li², Keyan Yu², Jian Wang², Xiaodong Zhang², Qinqin Yu², Cuiling Zhu², Yingjie Mei^3,4, Pu Xu³, Peiwei Yi³, Jiang Du⁵, and Yanqiu Feng^3
1Southern Medical University, Guang Zhou, China, ²Imaging department of Southern Medical University affiliated the third hospital, Guang Zhou, China, ³School of Biomedical Engineering, Guangdong Provincial Key Laborary of Medical Image Processing, Southern Medical University, Guang Zhou, China, ⁴Philips Healthcare, Guang Zhou, China, ⁵Department of Radiology, University of California San Diego, San Diego, CA, United States

In this preclinical study, we assessed feasibility of evaluating Gadolinium deposition in cortical bone by using recently developed actual flip angle variable repetition time 3D ultrashort echotime technique in rabbit model at 7T. Twenty times of administration of clinical equivalent dose of Magnevist and Gadovist that normalized according to body surface by U.S. FDA recommendation, and three times the dose of Gadovist (high-dose group) were investigated. Significant lower T1 values were observed in Magnevist administration group, Gadovist administration group and high-dose Gadovist administration group compared to control group, suggested T1 mapping might be a potential biomarker for evaluating Gadolinium deposition.

Dimitri Alexander Kessler¹, Mary A McLean², Titus Lanz³, Frank Riemer⁴, Rolf F Schulte⁵, Andrew Grainger¹, Fiona J Gilbert¹, Martin J Graves¹, and Joshua D Kaggie^1
1Department of Radiology, University of Cambridge, Cambridge, United Kingdom, ²Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, United Kingdom, ³Rapid Biomedical GmbH, Rimpar, Germany, ⁴Mohn Medical Imaging and Visualization Centre, Department of Radiology, Haukeland University Hospital Helse Bergen, Bergen, Norway, ⁵General Electric Healthcare, Munich, Germany

We present a method for bilateral sodium magnetic resonance imaging (MRI) of the lower extremities. Sodium MRI can provide direct information on tissue biochemistry not available through standard proton MRI, and could therefore potentially assist in disease diagnosis. Our preliminary results demonstrate the application of large field-of-view sodium MRI to the musculoskeletal system for potential compositional assessment of multiple tissues in both legs including muscle, cartilage, synovium and arteries.

Lumeng Cui¹, Emily J McWalter^1,2, Gerald Moran³, and Niranjan Venugopal^4
1Division of Biomedical Engineering, University of Saskatchewan, Saskatoon, SK, Canada, ²Department of Mechanical Engineering, University of Saskatchewan, Saskatoon, SK, Canada, ³Siemens Healthcare Limited, Oakville, ON, Canada, ⁴Department of Radiotherapy Physics, CancerCare Manitoba, Winnipeg, MB, Canada

Ultrashort echo time (UTE) pulse sequences have the unique ability to visualize short T2 tissues. While several UTE techniques have been implemented and demonstrated good clinical results, there currently does not exist a flexible and robust UTE pulse sequence which can easily manipulate multiple parameters “on-the-fly“ (i.e. selection of trajectories, excitation pulses, acquisition parameters, etc.), and obtain several complimentary scans in a single scan session. In this work we present a newly developed hybrid UTE pulse sequence that includes multiple excitation pulses, and varying trajectories, allowing for novel investigations in studying short T2 tissues.