Showing papers by "Sharmila Majumdar published in 2015"

Scoring hip osteoarthritis with MRI (SHOMRI): A whole joint osteoarthritis evaluation system

Abstract: Background: To develop a semi-quantitative MR-based hip osteoarthritis (OA) evaluation system (Scoring hip osteoarthritis with MRI, SHOMRI), and to test its reproducibility and face validity. Methods: The study involved 98 subjects with informed consent. Three-Tesla MR imaging of hip was performed in three planes with intermediate-weighted fat saturated FSE sequences. Two radiologists assessed cartilage loss, bone marrow edema pattern, subchondral cyst in 10 subregions, and assessed labrum in 4 subregions. In addition, presence or absence of ligamentum teres integrity, paralabral cysts, intra-articular body, and effusion in the hip joint were analyzed using the SHOMRI system. The reproducibility was assessed with intra-class correlation coefficient (ICC), Cohen’s Kappa values and percent agreement. SHOMRI scores were correlated with radiographic Kellgren-Lawrence (KL) and OARSI atlas gradings, and clinical parameters, the hip osteoarthritis outcome score (HOOS) and hip range of motion (ROM), using Spearman’s rank correlation and ordinal logistic regression. Results: ICC values were in the excellent range, 0.91 to 0.97. Cohen’s Kappa values and percent agreement ranged from 0.55 to 0.79 and 66 to 99%, respectively. SHOMRI demonstrated significant correlations with KL and OARSI gradings as well as with clinical parameters, HOOS and ROM (P < 0.05). Among the SHOMRI features, subchondral cyst and bone marrow edema pattern showed the highest correlation with HOOS and ROM.

International consensus on use of focused ultrasound for painful bone metastases: Current status and future directions.

Abstract: Focused ultrasound surgery (FUS), in particular magnetic resonance guided FUS (MRgFUS), is an emerging non-invasive thermal treatment modality in oncology that has recently proven to be effective for the palliation of metastatic bone pain. A consensus panel of internationally recognised experts in focused ultrasound critically reviewed all available data and developed consensus statements to increase awareness, accelerate the development, acceptance and adoption of FUS as a treatment for painful bone metastases and provide guidance towards broader application in oncology. In this review, evidence-based consensus statements are provided for (1) current treatment goals, (2) current indications, (3) technical considerations, (4) future directions including research priorities, and (5) economic and logistical considerations.

Higher Knee Flexion Moment During the Second Half of the Stance Phase of Gait Is Associated With the Progression of Osteoarthritis of the Patellofemoral Joint on Magnetic Resonance Imaging.

Abstract: Study Design Controlled laboratory study, longitudinal design. Objective To examine whether baseline knee flexion moment or impulse during walking is associated with the progression of osteoarthritis (OA) with magnetic resonance imaging of the patellofemoral joint (PFJ) at 1 year. Background Patellofemoral joint OA is highly prevalent and a major source of pain and dysfunction. The biomechanical factors associated with the progression of PFJ OA remain unclear. Methods Three-dimensional gait analyses were performed at baseline. Magnetic resonance imaging of the knee (high-resolution, 3-D, fast spin-echo sequence) was used to identify PFJ cartilage and bone marrow edema-like lesions at baseline and a 1-year follow-up. The severity of PFJ OA progression was defined using the modified Whole-Organ Magnetic Resonance Imaging Score when new or increased cartilage or bone marrow edema-like lesions were observed at 1 year. Peak external knee flexion moment and flexion moment impulse during the first and second hal...

Cartilage T1ρ and T2 Relaxation Times in Patients With Mild-to-Moderate Radiographic Hip Osteoarthritis.

Abstract: Author(s): Wyatt, Cory; Kumar, Deepak; Subburaj, Karupppasamy; Lee, Sonia; Nardo, Lorenzo; Narayanan, Divya; Lansdown, Drew; Vail, Thomas; Link, Thomas M; Souza, Richard B; Majumdar, Sharmila | Abstract: ObjectiveTo analyze region-specific T1ρ and T2 relaxation times of the hip joint cartilage in relation to presence or absence of radiographic hip osteoarthritis (OA) and presence or absence of magnetic resonance imaging (MRI)-detected cartilage defectsMethodsWeight-bearing radiographs and 3T MRI studies of the hip were obtained from 84 volunteers Based on Kellgren/Lawrence (K/L) scoring of the radiographs, 54 subjects were classified as healthy controls (K/L grade ≤1) and 30 were classified as having mild or moderate radiographic hip OA (K/L grades 2 or 3, respectively) Two-dimensional fat-suppressed fast spin-echo MRI sequences were used for semiquantitative clinical scoring of cartilage defects, and a T1ρ/T2 sequence was used to quantitatively assess the cartilage matrix The femoral and acetabular cartilage was then segmented into 8 regions and the mean T1ρ/T2 values were calculated Differences in T1ρ and T2 relaxation times were compared between subjects with and those without radiographic hip OA, and those with and those without femoral or acetabular cartilage defectsResultsHigher T1ρ and T2 relaxation times in the anterior superior and central regions of the acetabular cartilage were seen in individuals with radiographic hip OA and those with acetabular cartilage defects compared to their respective controls (P l 005) In the femoral cartilage, the differences in T1ρ and T2 were not significant for any of the comparisons Significant differences in the T1ρ and T2 values (each P l 005) were found in more subregions of the cartilage and across the whole cartilage when subjects were stratified based on the presence of MRI-detected cartilage defects than when they were stratified based on the presence of radiographic hip OAConclusionT1ρ and T2 relaxation parameters are sensitive to the presence of cartilage degeneration Both parameters may therefore support MRI evidence of cartilage defects of the hip

Are There Sex Differences in Knee Cartilage Composition and Walking Mechanics in Healthy and Osteoarthritis Populations

Abstract: Background Women are at a greater risk for knee osteoarthritis (OA), but reasons for this greater risk in women are not well understood. It may be possible that differences in cartilage composition and walking mechanics are related to greater OA risk in women.

Changes in MR relaxation times of the meniscus with acute loading: An in vivo pilot study in knee osteoarthritis

Abstract: THE MENISCUS, A fibrocartilaginous tissue found within the knee joint, is responsible for joint congruity, shock dissipation, load transmission, lubrication, and stability of the joint (1,2). The mechanical function of the meniscus largely depends on the structural and molecular integrity of its matrix, composed of a network of collagen fibers (type I and smaller amounts of type II) immobilizing proteoglycans (PG) (2,3). While PGs in the healthy meniscus resist large loads, it is the collagen fibrils arranged in fibrous lamellae that make meniscus efficient shock absorbers (4). Because of these functional roles, damage to or loss of the menisci affects the articular cartilage, as shown by the increased risk of developing osteoarthritis (OA) after meniscectomy (5). Traditionally, structural damage to the articular cartilage is considered as an initiator for the knee OA, but structural changes in the meniscus, which plays a critical role in the normal biomechanics and stability of the knee joint, may be a precursor to OA. Studies have also demonstrated that meniscal pathologies, such as meniscal degeneration and meniscal tears (6–8), are associated with change of the articular cartilage extracellular matrix (ECM) in patients in early or late stages of OA (9,10). The meniscus is increasingly being recognized as an important tissue in knee osteoarthritis (OA) (1–5). Morphological defects of meniscus and cartilage visualized with MRI are preceded by early degeneration of their ECM (8,10,11). In early stage osteoarthritis, the meniscal ECM exhibits increased proteoglycan content, loss of collagens, and less organized collagen fiber networks than those of normal menisci (12–18), and swelling, resulting in loss of mechanical properties. Changes in the matrix are an early and key finding in the evolution of OA as they likely alter the load distribution transmitted to the underlying articular cartilage. Thus, quantitative measures to detect and monitor changes that occur within the meniscus, both in unloaded and loaded conditions, could provide powerful diagnostic measurements for early-stage OA. Recent studies have shown the potential of MR relaxation times (T1ρ and T2) in studying biochemical composition of meniscus. This technology is promising for quantifying early meniscal degeneration and injury (15,19). These measures are highly sensitive to alterations in composition and structural integrity of collagen in the ECM of articular cartilage in vivo (20–22). Previous studies have shown that the collagen content and its orientation is the major factor in changes of cartilage T2 relaxation times (21,22). T2 relaxation time mapping is sensitive to a wide range of water interactions in tissue and in particular depends on the content, orientation and anisotropy of collagen and may therefore also play a role in assessing meniscal degeneration. While the exact contributor to T1ρ and T2 relaxation times remain disputed it is generally agreed upon that these metrics are sensitive to alterations in ECM composition and macromolecular structure and integrity. Rauscher et al reported promising results using this technique to quantify degenerative changes in the meniscal matrix in subjects with early OA (15). While several studies have investigated the use of these quantitative measures (T1ρ and T2) in assessing the effect of acute loading and physical exercise on articular cartilage (23–27), there is a lack of information regarding the affects of acute loading on meniscus relaxation times. Understanding the behavior of the meniscus relaxation times to acute loading may provide valuable information regarding the transmission of forces to the articular cartilage in persons with knee OA. Thus the purpose of this study was to evaluate changes in MR (T1ρ and T2) relaxation times in the meniscal body with acute loading in osteoarthritic knees and to compare these findings with those of age-matched healthy controls. The underlying hypothesis was that healthy knees will exhibit greater T1ρ and T2 change with loading when compared with osteoarthritic knees.

Improved differentiation between knees with cartilage lesions and controls using 7T relaxation time mapping

Abstract: Author(s): Wyatt, Cory; Guha, Aditi; Venkatachari, Anand; Li, Xiaojuan; Krug, Roland; Kelley, Douglas E; Link, Thomas; Majumdar, Sharmila | Abstract: Background/objectiveT1ρ and T2 relaxation mapping in knee cartilage have been used extensively at 3 Tesla (T) as markers for proteoglycan and collagen, respectively. The objective of this study was to evaluate the feasibility of T1ρ and T2 imaging of knee cartilage at 7T in comparison to 3T and to evaluate the ability of T1ρ and T2 to determine differences between normal and osteoarthritis (OA) patients.Materials and methodsTwenty patients, seven healthy patients (Kellgren-Lawrencen=n0), and 13 patients with signs of radiographic OA (Kellgren-Lawrencengn0) were scanned at 3T and 7T. The knee cartilage was segmented into six compartments and the T1ρ and T2 values were fit using a two-parameter model. Additionally, patients were stratified by the presence of cartilage lesions using the modified Whole Organ Magnetic Resonance Imaging Score classification of the knee. One-way analysis of variance was used to compare the healthy and OA groups at 3T and 7T. The specific absorption ratio was kept under Food and Drug Administration limits during all scans.ResultsT1ρ and T2 values at 3T and 7T were significantly higher in the lateral femoral condyle and patella in patients with OA. However, more regions were significant or approached significance at 7T compared with 3T, with the differences between healthy and OA patients also larger at 7T. The signal to noise ratio across all cartilage and meniscus compartments was 60% higher on average at 7T compared to 3T.ConclusionT1ρ imaging at 7T has been established as a viable imaging method for the differentiation of degenerated cartilage despite previous concerns over specific absorption rate and imaging time. The potential increased sensitivity of T1ρ and T2 imaging at 7T may be useful for future studies in the development of OA.

Bone Remodeling after MR Imaging–guided High-Intensity Focused Ultrasound Ablation: Evaluation with MR Imaging, CT, Na18F-PET, and Histopathologic Examination in a Swine Model

Abstract: This exploratory MR imaging, CT, and PET study demonstrated a progressive pattern of bone remodeling after MR imaging–guided high-intensity focused ultrasound ablation.

Quantitative evaluation of atlas-based MR attenuation correction for brain PET imaging using a time-of-flight PET/MRI system: A direct comparison with CT-based attenuation correction

Abstract: 259 Objectives CT-atlas-based bone-anatomy compensation for MR-based attenuation correction (MRAC) in brain PET imaging using PET/MRI is a current standard. It is important to ensure the quantitative accuracy of this technique in the combined PET/MRI system. Methods Whole-body FDG-PET/CT followed by PET/MRI were performed for twelve patients. Using the same PET raw data from PET/MRI, time-of-flight (TOF) iterative reconstruction was performed with the attenuation correction applied using atlas-based MRAC as well as CTAC from PET/CT. CT images were aligned to MR images before CTAC was applied. For quantitative evaluation, PET mean activity concentration values were measured and compared in eight 10 ml volumes-of-interest (VOI). Results PET activity concentration with the atlas-based MRAC was systematically underestimated on average by 0.64±0.29 kBq/ml (3.9±1.5%). In addition, the results were patient-specific (highest: 6.9% vs. lowest: 1.0%) and VOI-specific (highest: 5.6% vs. lowest: 2.6%). Specifically, the highest discrepancy (5.6%) between PET/MRAC and PET/CTAC occurred at the cerebellum (VOI #7). Also, the patient-specific difference images for AC maps and PET reconstructions show that skull differences between MRAC and CTAC resulted in a small but measurable underestimation of activities on PET/MR. Conclusions For the first time, the atlas-based MRAC was evaluated for brain PET imaging in an integrated TOF-PET/MRI system. Overall, the MRAC achieves quantification accuracy similar to CTAC with a small but measurable difference of 5% in values. Further studies are needed to determine if this difference is clinically significant as well as the etiology of the patient specific differences. Additionally, since the skull has the greatest contribution to AC difference, bone-enhancing MR pulse sequences such as ultra-short or zero echo-time (UTE/ZTE) may improve the accuracy of PET quantitation compared to the CT-based bone atlas.

Impact of atlas-CT-based bone anatomy compensation on MR-based attenuation correction for brain PET imaging in a time-of-flight PET/MRI system: A direct comparison to a patient-CT-based approach.

Abstract: An atlas-CT-based bone-anatomy compensation for MR-based attenuation correction (MRAC) in brain PET/MRI imaging is a current standard. However, the impact of an anatomical difference has not been clinically evaluated. Thus, we aim to evaluate the impact of the anatomical dissimilarity on MRAC. Whole-body FDG-PET/CT followed by PET/MRI were performed for twelve patients in an integrated TOF PET/MRI system. The MRAC utilized an atlas-CT (MRAC-atlas) as well as a patient-specific-CT (MRAC patient) to produce AC maps (pseudo-CT). Instead of using atlas-CT, the MRAC-patient approach derived pseudo-CT from patient-specific-CT aligned to MR. For quantitative evaluation, CTAC was considered as gold standard for AC, and PET mean activity concentration values were measured and compared in eight 10 ml volumes-of-interest (VOI). PET activity concentration with MRAC, compared to CTAC, were systematically underestimated on average by 0.63±0.34 kBq/ml (4.0±2.2%) and 0.22±0.21 kBq/ml (1.4±1.5%) for the MRAC-atlas and the MRAC-patient, respectively: using the MRAC atlas, the error was increased to 0.41±0.25 kBq/ml (2.6±1.8%) on average (p≈0). However, the error increase was patient-dependent (highest: 5.7% vs. lowest: 0.3%) and VOI dependent (highest 3.1% vs. lowest: 1.9%). For the first time, the atlas-CT based MRAC was compared to the patient-specific-CT-based MRAC for brain PET imaging in an integrated TOF PET/MRI system. Overall, the MRAC-atlas achieves quantification accuracy similar to CTAC with a small but measurable difference of 5% in values, which is 2.6% higher than the error of the MRAC-patient.

Imaging Specific to Cartilage Injury

Abstract: Magnetic resonance imaging (MRI) has been used for morphological joint imaging, allowing visualization of abnormalities in cartilage, ligaments, bone, and other anatomical features. Quantitative MRI sequences provide noninvasive or minimally invasive means to assess proteoglycan and collagen integrity. These sequences vary in sensitivity to macromolecular content and differences between native and repair cartilage. When these standard MR sequences are used to image repaired cartilage, the presence of implanted metallic objects interferes and causes artifacts in the images affecting the clinical outcomes. Different types of artifacts, pulse sequences currently used, and emerging techniques to minimize these artifacts are discussed.