Joint Annual Meeting ISMRM-ESMRMB 2014 10-16 May 2014 Milan, Italy

COMBINED EDUCATIONAL & SCIENTIFIC SESSION
Osteoporosis Hybrid Imaging
SKILL LEVEL: Intermediate to Advanced
ORGANIZERS: Richard Kijowski, M.D., William B. Morrison, M.D. & Ravinder Regatte, Ph.D.
Wednesday, 14 May 2014
 
OVERVIEW
The course will provide an in-depth discussion of advanced MRI techniques for evaluating bone architecture and composition. The lectures will discuss the technical aspects and the clinical and research applications of emerging MRI methods for imaging cortical and trabecular bone. The didactic lectures will be followed by presentation of scientific abstracts discussing novel MRI techniques for evaluating bone architecture and composition. The course is intended to bridge the gap between basic science research and patient care.
 
TARGET AUDIENCE
“Osteoporosis Hybrid Imaging” is directed at clinicians interested in learning about emerging MRI techniques used to assess bone architecture and composition and basic science researchers seeking to enhance their knowledge on clinical applications of novel MRI technology.
 
EDUCATIONAL OBJECTIVES

As a result of attending this course, participants should be able to:

  • Identify emerging MRI techniques for evaluating bone architecture and composition; and
  • Refine or apply new MRI techniques to assess bone architecture and composition in clinical practice and osteoporosis research studies.
 

PROGRAM

Moderators: Gregory Chang, M.D. & Sharmila Majumdar, Ph.D.

         
10:00 Clinical Imaging of Osteoporosis Thomas M. Link, M.D., Ph.D.
10:30 Advanced Quantitative MRI of Bone Structure & Mechanics Felix W. Wehrli, Ph.D.
         
11:00 0506.   
MRI Measures of Cortical Bone Water Concentration: Dependence on Age and Pore Volume Fraction
Alan C. Seifert1, Cheng Li1, Hamidreza Saligheh Rad1, Chamith S. Rajapakse1, Wenli Sun1, Shing Chun Benny Lam1, and Felix W. Wehrli1
1Radiology, University of Pennsylvania, Philadelphia, PA, United States

 
Increased cortical porosity is a major cause of impaired strength of osteoporotic bone. Ultrashort echo-time MRI can detect short-T2 components in cortical bone and enables measurement of bulk bone water content (BWC). The suppression ratio (SR, ratio of signal without and with long-T2 suppression) may better reflect bone porosity. BWC is quantified in 72 humans and SR in 40 humans and 13 bone specimens, and these measurements are compared to x-ray-based modalities. Although SR is not an absolute measurement of pore volume fraction, SR is more highly correlated with age and porosity than pQCT mineral density or BWC.

 
11:10 0507.   
Linkage of vertebral bone marrow fat content with biomechanical strength and trabecular bone structure parameters
Thomas Baum1, Stefan Ruschke1, Olga Gordijenko1, Eduardo Grande Garcia1, Hendrik Kooijman2, Rainer Burgkart3, Ernst J Rummeny1, Jan S Bauer4, and Dimitrios C Karampinos1
1Department of Radiology, Klinikum rechts der Isar, Technische Universität München, Munich, Bavaria, Germany, 2Philips Healthcare, Hamburg, Hamburg, Germany, 3Department of Orthopedics and Orthopedic Sports Medicine, Technische Universität München, Munich, Bavaria, Germany,4Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Bavaria, Germany

 
There is a growing interest in understanding the linkage between bone marrow adiposity and bone weakening. The present pilot ex vivo study investigates, using human spine specimens, the relationship between MRS-based vertebral bone marrow proton density fat fraction, MDCT-based measures of BMD and trabecular microstructure, and biomechanical strength. The reported results confirm the previously reported negative association between bone marrow fat content and bone mineral density and provide the first direct validation of a negative association between bone marrow fat content and bone biomechanical strength.

 
11:20 0508.   Simultaneous fat, water and T2* mapping of trabecular bone and comparison with high resolution MRI in the hip
Pippa Storey1, Gregory Chang1, Stephen Honig2, Kashif Khokhar1, Mary T. Bruno1, David R. Stoffel1, and Sandra L. Moore1
1Radiology Department, New York University School of Medicine, New York, NY, United States, 2Division of Rheumatology, New York University School of Medicine, New York, NY, United States

 
Destruction of trabecular bone can result from osteoporosis or malignant processes, and is difficult to characterize adequately using conventional methodologies. We compared simultaneous fat, water and T2* mapping with high resolution trabecular imaging in the hips of 30 patients with osteoporosis or osteopenia. T2* is known to be sensitive to trabecular density since the magnetic susceptibility of mineralized bone differs from that of marrow. In addition, fat content may potentially allow discrimination of osteoporosis from malignant infiltration. Elevated T2* was found to be correlated with trabecular paucity, both in terms of anatomic distribution and across patients (Spearman r=0.64, p=0.00014).

 
11:30 0509.   
Predicting Whole Bone Strength in Radii Using MRI Measurements of Bound and Pore Water
Mary Kate Manhard1,2, Sasidhar Uppuganti3, Mathilde C Granke3, Jeffry S Nyman3, and Mark D Does1,2
1Biomedical Engineering, Vanderbilt University, Nashville, TN, United States, 2Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States, 3Department of Orthopaedics & Rehab, Vanderbilt University, Nashville, TN, United States

 
Ultra-short echo time (UTE) measures of bound and pore water using the DAFP and AIR sequences were found in cortical bone of the radius in cadaveric specimens. The concentrations of bound and pore water were correlated to mechanical properties found from a three-point bend test. DXA and μCT imaging measures on the same bones were also correlated to mechanical properties. Bound and pore water correlated well with bending strength, while DXA and μCT showed slightly weaker correlations. Additionally, bound water was significantly correlated with toughness. These results validate the potential for MRI as a useful tool for predicting fracture risk.

 
11:40 0510.   Ultrashort Echo Time Magnetization Transfer (UTE-MT) Imaging of Cortical Bone
Jiang Du1, Shihong Li1, Won Bae1, Reni Biswas1, Sheronda Statum1, Eric Chang1, and Christine B Chung1
1Radiology, University of California, San Diego, San Diego, CA, United States

 
Magnetization transfer (MT) imaging is one way of indirectly assessing pools of protons with extremely fast transverse relaxation. However, conventional long TE MT imaging sequences are not applicable to short T2 tissues such as cortical bone. Ultrashort echo time (UTE) sequences can detect signal from short T2 species. The combination of UTE with MT (UTE-MT) provides a valuable option to assess different bone components. In this study we evaluated UTE-MT imaging of cortical bone and its application in assessing cortical porosity and biomechanical properties of cadaveric human bone samples using a clinical whole body 3T scanner.

 
11:50 0511.   Muscle-based pharmacokinetic model for bone marrow perfusion study - permission withheld
Heather T. Ma1, James F. Griffith2, Chenfei Ye3, Xinxin Zhao4, and David K. Yeung2
1Harbin Institute of Technology Shenzhen Graduate School, Shenzhen, Guangdong, China, 2Department of Imaging and Interventional Radiology, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong, 3Department of Electronic and Information Engineering, Harbin Institute of Technology Shenzhen Graduate School, Shenzhen, Guangdong, China, 4Department of Electronic and Information Engineering, Harbin Institute of Technology Shenzhen Graduate School, Guangdong, China

 
This study characterized bone marrow perfusion properties in a quantitative way by adopting surrounding muscle as the reference. A muscle-based pharmacokinetic model was established by adapting a reference region-based model in the bone marrow. Contrast agent extravasation rate constants for bone marrow and the extravascular-extracellular volume fractions for muscle were observed to diminish with the decreased bone mineral density (BMD), while muscle perfusion indices had no significant change among groups with different BMD. The results indicated that the impaired perfusion function is only a function of the bone marrow and not of the adjacent musculature.

 
         
12:00     Adjournment