Yoonho Nam¹, Joon-Yong Jung¹, Hyun Seok Choi¹, Eojin Hwang¹, Hongpyo Lee², and Dong-Hyun Kim^2
1Department of Radiology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea, Republic of, ²Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea, Republic of

Fat fraction of the bone marrow has been suggested as an important quantitative parameter in the assessment of treatment response and determination of the benignity in oncologic imaging. Therefore, accurate fat quantification is a prerequisite for the fat fraction to be established as a reliable imaging biomarker. For this purpose, spoiled gradient echo sequences have been commonly used. However, gradient echo imaging is susceptible to B₀ variations from various sources such as respiration, cardiac pulsation. In this study, we investigate and compensate the effects of respiration-induced B₀ variations on fat quantification of the bone marrow in the lumbar spine.

Jeff L. Zhang¹, Christopher Hanrahan¹, Christopher C. Conlin¹, Corey Hart², Gwenael Layec², Kristi Carlston¹, Daniel Kim¹, Michelle Mueller³, and Vivian S. Lee^1
1Radiology, University of Utah, Salt Lake City, UT, United States, ²Internal Medicine, University of Utah, Salt Lake City, UT, United States, ³Vascular surgery, University of Utah, Salt Lake City, UT, United States

Noninvasive mapping of calf muscle perfusion with high spatial resolution has potential for assessing the severity of peripheral artery disease (PAD) and studying associated capillary density abnormality. We tested our novel DCE-MRI method to measure calf muscle hyperemia stimulated by plantar flexion at three different workloads. Increases in exercise load caused increased total perfusion in gastrocnemius, with a heterogeneous pattern at medium load and homogeneous at higher load. Perfusion in soleus did not increase until very heavy load of 16 lbs. DCE-MRI provides high spatial resolution measurement of post-exercise muscle perfusion.  

Ping Wang^1,2, Muge Serpil Deger³, Hakmook Kang⁴, T. Alp Ikizler³, Jens M. Titze⁵, and John C. Gore^1,2
1Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, United States, ²Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, United States, ³Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States, ⁴Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN, United States, ⁵Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States

Sodium ions play a vital role in cellular homeostasis and electrochemical activity throughout the human body.  Previous studies have measured muscle and skin sodium contents in vivo in humans using MRI and have shown characteristic changes with age and as a result of pathological changes.  In this study, we found significant gender differences in sodium deposition between muscle and skin, with male has higher sodium content in skin than in muscle, while female has higher muscle sodium than skin sodium.  This observation seems to be more reliable with the increase of age.
 

Eric Y Chang^1,2, Robert M Healey³, Reni Biswas², Sheronda Statum², Betty Tran², Kenyu Iwasaki⁴, Jiang Du², Won C Bae², and Christine B Chung^1,2
1Radiology Service, VA San Diego Healthcare System, San Diego, CA, United States, ²Department of Radiology, University of California, San Diego Medical Center, San Diego, CA, United States, ³Department of Orthopaedic Surgery, University of California, San Diego Medical Center, San Diego, CA, United States, ⁴Department of Orthopaedic Surgery, Kyushu University, Fukuoka, Japan

In this pilot study, we sought to determine if mono-exponential T2, mono-exponential UTE-T2*, or bi-exponential UTE-T2* correlated with biomechanical properties in human Achilles tendons. We found very high and significant correlation coefficients between mono-exponential T2* (rho = 0.90, p = 0.002) and bi-exponential T2* fractions (rho = -0.97, p < 0.001) obtained using the UTE-Cones sequence and ultimate tensile strain. Ultimate tensile strain represents the percentage change in tendon length prior to failure and high strains have been previously associated with tendon degeneration. Our results suggest that non-invasive MRI of the Achilles tendon may serve as a surrogate measure.

Benjamin C Rowland¹ and Alexander P Lin^1
1Centre for Clinical Spectroscopy, Brigham and Women's Hospital, Boston, MA, United States

 MR spectroscopy is often used to study dynamic systems, such as muscle energetics using ³¹P. The need to perform temporal averaging to improve signal to noise ratios can compromise the temporal resolution of the measurements. Indirect time domain denoising can help to resolve this issue. In this study we evaluate six potential denoising approaches for dynamic MRS.

Mary Kate Manhard¹, Sasidhar Uppuganti², Mathilde C Granke², Daniel F Gochberg³, Jeffry S Nyman², and Mark D Does^1
1Biomedical Engineering, Vanderbilt University, Nashville, TN, United States, ²Department of Orthopaedics & Rehabilitation, Vanderbilt University, Nashville, TN, United States, ³Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States

Bound and pore water concentration measures of cortical bone found from MRI have been shown to correlate with material properties of bone, but the ideal way to analyze and draw information from 3D quantitative maps remains unclear. Material properties of cadaver radii found from a 3-point bend test were correlated with characteristics of the distribution of bound and pore water concentrations (e.g. mean, skewness) in ROIs found from different segmentations. Results highlighted the importance of segmentation method as well as quantitative measures drawn from the maps.  

Tan Guo¹, Dandan Zheng², Bing Wu², and Min Chen^1
1Radiology, Beijing Hospital, Beijing, China, People's Republic of, ²GE Healthcare, MR Research China, Beijing, Beijing, China, People's Republic of

The blood supply of meniscus is an essential indicator for the prognosis of meniscal problems. With a favorable blood supply of the teared meniscus, it’s tend to preserve the meniscus as much as possible at partial meniscetomy and meniscal repair. Intravoxel incoherent motion (IVIM) theory provide information about microcirculation of blood in addition to the pure molecular diffusion. The perfusion information detected with IVIM is emphasized on microvascular bed, which is the typical blood supply pattern of meniscus. In this study, IVIM model were used to estimate the change of vasculature in normal, degenerated and teared meniscus.

Jari Rautiainen¹, Lassi Rieppo^2,3, Simo Saarakkala^2,3,4, and Mikko Johannes Nissi^1,5
1Department of Applied Physics, University of Eastern Finland, Kuopio, Finland, ²Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland, ³Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland, ⁴Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland, ⁵Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland

Classical ($$$T_1$$$, $$$T_2$$$) and several rotating frame quantitative MR parameters have been used for evaluation of composition and structure of articular cartilage, and demonstrated to have variable sensitivity to tissue orientation. The orientation dependence of $$$T_1$$$, $$$T_2$$$, $$$T_2^*$$$, CW-$$$T_{1\rho}$$$ with four spin-lock amplitudes, adiabatic $$$T_{1\rho}$$$ with three different pulse modulations, adiabatic $$$T_{2\rho}$$$ and $$$T_{\rm RAFF}$$$ relaxation times were further investigated at 9.4T at different orientations of articular cartilage relative to B0 and compared with polarized light microscopy of the same tissue. $$$T_1$$$, adiabatic $$$T_{1\rho}$$$ with HS1-pulse and CW-$$$T_{1\rho}$$$ at 2 kHz spin-lock demonstrated the least orientation dependence.

Xinwei Lei¹, Jin QU¹, Ying ZHAN¹, Huixia Li¹, and Yu Zhang^2
1Tianjin First Center Hospital, Tianjin, China, People's Republic of, ²Philips Healthcare, Beijin, China, People's Republic of

The aim of study was to explore whether synovitis and bone erosion judged by ADC values correspond exactly or not to those judged by CE-MRI. 25 patients were examined by 3.0T MR including DWI and CE-MRI. ADC value of synovitis and bone erosion was signi?cantly lower than that of joint effusion and cysts. ADC values of 2.0 was found distinguishing joint effusion from synovitis, and bone erosion from cysts. Therefore, MR diffusion provides additional information to the routine MRI sequences rendering it an effective non-invasive tool in differentiating between synovitis and joint effusion, as well as bone erosion and cysts.

Lisa Maria Harris^1,2, Ella Hodder^2,3, Mara Cercignani², Jan Bush², Derek Convill³, Paul Colley¹, and Nicholas Dowell^2
1Radiological Sciences, Brighton and Sussex University Hospitals NHS Trust, Brighton, United Kingdom, ²Clinical Imaging Sciences Centre, Brighton and Sussex Medical School, Brighton, United Kingdom,³Computing, Engineering and Mathematics, University of Brighton, Brighton, United Kingdom

An assessment was made to determine whether proteoglycan concentration could accurately be quantified at 1.5T using 1HMRS in a group of 13 healthy volunteers.  A peak from the N-acetyl resonance associated with proteoglycan was seen in all thirteen spectra, and reliably measured (308.8±59.9).  This compares favourably with studies performed at higher field strengths, thus showing that is it possible even at 1.5T to measure proteoglycans in intervertebral discs.