Stephen Matzat | Stanford University (original) (raw)

Papers by Stephen Matzat

Advanced Quantitative Imaging of Knee Joint Repair, 2014

Journal of magnetic resonance imaging : JMRI, Jan 22, 2014

To compare T2 relaxation time measurements between MR pulse sequences at 3 Tesla in agar phantoms... more To compare T2 relaxation time measurements between MR pulse sequences at 3 Tesla in agar phantoms and in vivo patellar, femoral, and tibial articular cartilage. T2 relaxation times were quantified in phantoms and knee articular cartilage of eight healthy individuals using a single echo spin echo (SE) as a reference standard and five other pulse sequences: multi-echo SE (MESE), fast SE (2D-FSE), magnetization-prepared spoiled gradient echo (3D-MAPSS), three-dimensional (3D) 3D-FSE with variable refocusing flip angle schedules (3D vfl-FSE), and quantitative double echo steady state (qDESS). Cartilage was manually segmented and average regional T2 relaxation times were obtained for each sequence. A regression analysis was carried out between each sequence and the reference standard, and root-mean-square error (RMSE) was calculated. Phantom measurements from all sequences demonstrated strong fits (R(2) > 0.8; P < 0.05). For in vivo cartilage measurements, R(2) values, slope, and ...

Current rheumatology reports, 2014

Efforts to reduce the ever-increasing rates of osteoarthritis (OA) in the developed world require... more Efforts to reduce the ever-increasing rates of osteoarthritis (OA) in the developed world require the ability to non-invasively detect the degradation of joint tissues before advanced damage has occurred. This is particularly relevant for damage to articular cartilage because this soft tissue lacks the capacity to repair itself following major damage and is essential to proper joint function. While conventional magnetic resonance imaging (MRI) provides sufficient contrast to visualize articular cartilage morphology, more advanced imaging strategies are necessary for understanding the underlying biochemical composition of cartilage that begins to break down in the earliest stages of OA. This review discusses the biochemical basis and the advantages and disadvantages associated with each of these techniques. Recent implementations for these techniques are touched upon, and future considerations for improving the research and clinical power of these imaging technologies are also discus...

Quantitative imaging in medicine and surgery, 2013

Due to aging populations and increasing rates of obesity in the developed world, the prevalence o... more Due to aging populations and increasing rates of obesity in the developed world, the prevalence of osteoarthritis (OA) is continually increasing. Decreasing the societal and patient burden of this disease motivates research in prevention, early detection of OA, and novel treatment strategies against OA. One key facet of this effort is the need to track the degradation of tissues within joints, especially cartilage. Currently, conventional imaging techniques provide accurate means to detect morphological deterioration of cartilage in the later stages of OA, but these methods are not sensitive to the subtle biochemical changes during early disease stages. Novel quantitative techniques with magnetic resonance imaging (MRI) provide direct and indirect assessments of cartilage composition, and thus allow for earlier detection and tracking of OA. This review describes the most prominent quantitative MRI techniques to date-dGEMRIC, T2 mapping, T1rho mapping, and sodium imaging. Other, less...

PURPOSE/AIM The purpose of this exhibit is to: Emphasize the importance of quantitative imaging t... more PURPOSE/AIM The purpose of this exhibit is to: Emphasize the importance of quantitative imaging techniques to assess cartilage biochemical composition and quality for research on osteoarthritis (OA), the most common joint disease with tremendous consequences for patients and healthcare. Learn about basic principles, and Review a wide range of novel MRI and CT-based quantitative imaging techniques for cartilage composition. CONTENT ORGANIZATION Impact of OA and need for quantitative imaging techniques in OA research Basic principles of quantitative radiological imaging techniques for cartilage composition Review of the following quantitative imaging techniques for cartilage composition: Delayed gadolinium enhanced MRI of cartilage (dGEMRIC) T2 mapping T1rho Ultrashort echo time (UTE) GAG-specific chemical exchange saturation transfer (gagCEST) Sodium MRI Quantitative CT arthrography Of each technique we discuss outcome measures, biochemical correlates, pros/cons, reported application...

Advanced Quantitative Imaging of Knee Joint Repair, 2014

Journal of magnetic resonance imaging : JMRI, Jan 22, 2014

To compare T2 relaxation time measurements between MR pulse sequences at 3 Tesla in agar phantoms... more To compare T2 relaxation time measurements between MR pulse sequences at 3 Tesla in agar phantoms and in vivo patellar, femoral, and tibial articular cartilage. T2 relaxation times were quantified in phantoms and knee articular cartilage of eight healthy individuals using a single echo spin echo (SE) as a reference standard and five other pulse sequences: multi-echo SE (MESE), fast SE (2D-FSE), magnetization-prepared spoiled gradient echo (3D-MAPSS), three-dimensional (3D) 3D-FSE with variable refocusing flip angle schedules (3D vfl-FSE), and quantitative double echo steady state (qDESS). Cartilage was manually segmented and average regional T2 relaxation times were obtained for each sequence. A regression analysis was carried out between each sequence and the reference standard, and root-mean-square error (RMSE) was calculated. Phantom measurements from all sequences demonstrated strong fits (R(2) > 0.8; P < 0.05). For in vivo cartilage measurements, R(2) values, slope, and ...

Current rheumatology reports, 2014

Efforts to reduce the ever-increasing rates of osteoarthritis (OA) in the developed world require... more Efforts to reduce the ever-increasing rates of osteoarthritis (OA) in the developed world require the ability to non-invasively detect the degradation of joint tissues before advanced damage has occurred. This is particularly relevant for damage to articular cartilage because this soft tissue lacks the capacity to repair itself following major damage and is essential to proper joint function. While conventional magnetic resonance imaging (MRI) provides sufficient contrast to visualize articular cartilage morphology, more advanced imaging strategies are necessary for understanding the underlying biochemical composition of cartilage that begins to break down in the earliest stages of OA. This review discusses the biochemical basis and the advantages and disadvantages associated with each of these techniques. Recent implementations for these techniques are touched upon, and future considerations for improving the research and clinical power of these imaging technologies are also discus...

Quantitative imaging in medicine and surgery, 2013

Due to aging populations and increasing rates of obesity in the developed world, the prevalence o... more Due to aging populations and increasing rates of obesity in the developed world, the prevalence of osteoarthritis (OA) is continually increasing. Decreasing the societal and patient burden of this disease motivates research in prevention, early detection of OA, and novel treatment strategies against OA. One key facet of this effort is the need to track the degradation of tissues within joints, especially cartilage. Currently, conventional imaging techniques provide accurate means to detect morphological deterioration of cartilage in the later stages of OA, but these methods are not sensitive to the subtle biochemical changes during early disease stages. Novel quantitative techniques with magnetic resonance imaging (MRI) provide direct and indirect assessments of cartilage composition, and thus allow for earlier detection and tracking of OA. This review describes the most prominent quantitative MRI techniques to date-dGEMRIC, T2 mapping, T1rho mapping, and sodium imaging. Other, less...

PURPOSE/AIM The purpose of this exhibit is to: Emphasize the importance of quantitative imaging t... more PURPOSE/AIM The purpose of this exhibit is to: Emphasize the importance of quantitative imaging techniques to assess cartilage biochemical composition and quality for research on osteoarthritis (OA), the most common joint disease with tremendous consequences for patients and healthcare. Learn about basic principles, and Review a wide range of novel MRI and CT-based quantitative imaging techniques for cartilage composition. CONTENT ORGANIZATION Impact of OA and need for quantitative imaging techniques in OA research Basic principles of quantitative radiological imaging techniques for cartilage composition Review of the following quantitative imaging techniques for cartilage composition: Delayed gadolinium enhanced MRI of cartilage (dGEMRIC) T2 mapping T1rho Ultrashort echo time (UTE) GAG-specific chemical exchange saturation transfer (gagCEST) Sodium MRI Quantitative CT arthrography Of each technique we discuss outcome measures, biochemical correlates, pros/cons, reported application...