Faculty Bibliography

Background/Purpose: To investigate the expression of vascular adhesion protein -1 (VAP-1) in joint tissues and serum in knee osteoarthritis (OA) patients and examine whether VAP-1 levels predict increased risk of disease severity or progression of knee OA.
Method(s): Baseline serum and synovial fluid VAP-1/semicarbazide-sensitive amine oxidase (SSAO) levels were assessed in cohorts of patients with tibiofemoral medial knee OA and healthy subjects. Standardized fixed-flexion posteroanterior knee radiographs were scored for Kellgren Lawrence (KL) grade (0-4) and medial joint space width (JSW) at the mid-portion of the joint space. Radiographic severity was defined by KL2/3 vs. KL4. Biochemical markers assessed comprised VAP-1/ SSAO, IL-1Ra, IL-6, sRAGE, CCL2, CCL4, CD163, hsCRP and MMPs-1,-3,-9. Associations between biomarkers and radiographic severity (logistic regression controlling for covariates) and pain (Spearman correlation) were evaluated.
Result(s): VAP-1 was locally overexpressed at least 2 fold in the OA synovium based on immunohistochemical, microarray and qRT-PCR analyses compared to controls. Synovial fluid SSAO levels was also significantly higher in OA (107.94+41.42) compared to normals (38.12 + 22.98 ng/ml; p=0.0001) and inversely associated with radiographic severity. We observed a positive correlation with the levels of SSAO in the synovial fluid and serum of OA patients (r=0.47; p=0.014). However, serum SSAO levels in OA patients were lower than in controls, and inversely correlated with pain and inflammation markers (CRP and soluble RAGE). Serum SSAO levels were also lower in radiographically severe (KL4) OA patients compared to KL2/3. Serum SSAO did not correlate with other markers of inflammation or radiographic joint space narrowing (JSN) over 24 months.
Conclusion(s): Synovial fluid VAP-1/SSAO levels were elevated in OA and correlate with radiographic severity. However, serum or circulating SSAO levels are lower in OA patients and inversely correlate with pain and inflammation. Serum VAP-1 levels could identify patients at increased risk for knee radiographic severity

Radiographs are indicated as the first imaging test in all patients with chronic wrist pain, regardless of the suspected diagnosis. When radiographs are normal or equivocal, advanced imaging with MRI (without or without intravenous contrast or following arthrography), CT (usually without contrast), and ultrasound each has a role in establishing a diagnosis. Furthermore, these examinations may contribute to staging disease, treatment planning, and prognostication, even when radiographs are diagnostic of a specific condition. Which examination or examinations are best depends on the specific location of pain and the clinically suspected conditions. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

PURPOSE: Diffusion tensor imaging (DTI) of articular cartilage is a promising technique for the early diagnosis of osteoarthritis (OA). However, in vivo diffusion tensor (DT) measurements suffer from low signal-to-noise ratio (SNR) that can result in bias when estimating the six parameters of the full DT, thus reducing sensitivity. This study seeks to validate a simplified four-parameter DT model (zeppelin) for obtaining more robust and sensitive in vivo DTI biomarkers of cartilage. METHODS: We use simulations in a substrate to mimic changes during OA; and analytic simulations of the DT drawn from a range of fractional anisotropies (FA) measured with high-quality DT data from ex vivo human cartilage. We also use in vivo data from the knees of a healthy subject and two OA patients with Kellgren-Lawrence (KL) grades 1 and 2. RESULTS: For simulated in vivo cartilage SNR ( approximately 25) and anisotropy levels, the estimated mean values of MD from the DT and zeppelin models were identical to the ground truth values. However, zeppelin's FA is more accurate in measuring water restriction. More specifically, the FA estimations of the DT model were additionally biased by between +2% and +48% with respect to zeppelin values. Additionally, both mean diffusivity (MD) and FA of the zeppelin had lower parameter variance compared to the full DT (F-test, P < 0.05). We observe the same trends from in vivo values of patient data. CONCLUSION: The zeppelin is more robust than the full DT for cartilage diffusion anisotropy and SNR at levels typically encountered in clinical applications of articular cartilage. Magn Reson Med, 2017. (c) 2017 International Society for Magnetic Resonance in Medicine.

Total knee arthroplasty (TKA) is the most commonly performed joint replacement procedure in the United States and annual demand for primary TKA is expected to grow by 673% by 2030. The first part provides an overview of imaging modalities (radiographs, CT, MRI, ultrasound, and various nuclear medicine studies) and discusses their usefulness in the imaging evaluation of TKA. The second part focuses on evidence-based imaging and imaging-guided intervention algorithms for the workup of TKA and its complications, including routine follow-up, component wear, periprosthetic infection, aseptic loosening, granulomas/osteolysis, conventional and rotational instability, periprosthetic fracture, patellar complications, and a variety of periprosthetic soft tissue abnormalities. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

OBJECTIVE: We are fortunate to live in a time when real advances in medicine are happening at an increasingly rapid pace. This is especially true in the field of radiology, and keeping abreast of these advances is one of the main challenges of clinical practice. Traditionally, cutting edge techniques in our field have been researched and validated at major academic medical centers before slowly making their way into the armamentarium of routine clinical practice. However, the improved ability to communicate and disseminate information in our modern age has facilitated more rapid implementation of new techniques to allow us to better serve our patients. CONCLUSION: As such, this article aims to review the current standards for MRI of the shoulder used in routine practice. Furthermore, we will discuss some of the most recent advances in shoulder MRI, with particular emphasis on the applicability of an additional axial 3D T1-weighted FLASH sequence with Dixon-based water-fat separation in routine clinical practice that can be useful in characterizing several commonly encountered pathologic processes of the shoulder joint.

PURPOSE: We establish a mechanical injury model for articular cartilage to assess the sensitivity of diffusion tensor imaging (DTI) in detecting cartilage damage early in time. Mechanical injury provides a more realistic model of cartilage degradation compared with commonly used enzymatic degradation. METHODS: Nine cartilage-on-bone samples were obtained from patients undergoing knee replacement. The 3 Tesla DTI (0.18 x 0.18 x 1 mm3 ) was performed before, 1 week, and 2 weeks after (control zero, mild, and severe) injury, with a clinical radial spin-echo DTI (RAISED) sequence used in our hospital. We performed stress-relaxation tests and used a quasilinear-viscoelastic (QLV) model to characterize cartilage mechanical properties. Serial histology sections were dyed with Safranin-O and given an OARSI grade. We then correlated the changes in DTI parameters with the changes in QLV-parameters and OARSI grades. RESULTS: After severe injury the mean diffusivity increased after 1 and 2 weeks, whereas the fractional anisotropy decreased after 2 weeks (P < 0.05). The QLV-parameters and OARSI grades of the severe injury group differed from the baseline with statistical significance. The changes in mean diffusivity across all the samples correlated with the changes in the OARSI grade (r = 0.72) and QLV-parameters (r = -0.75). CONCLUSION: DTI is sensitive in tracking early changes after mechanical injury, and its changes correlate with changes in biomechanics and histology. Magn Reson Med, 2016. (c) 2016 Wiley Periodicals, Inc.

OBJECTIVE: OA pathogenesis includes both mechanical and inflammatory features. Studies have implicated synovial fluid urate (UA) as a potential OA biomarker, possibly reflecting chondrocyte damage. Whether serum urate (sUA) levels reflect/contribute to OA is unknown. We investigated whether sUA predicts OA progression in a non-gout knee OA population. METHODS: Eighty-eight subjects with medial knee OA (BMI <33) but without gout were included. Baseline sUA was measured in previously banked serum. At 0 and 24 months, subjects underwent standardized weight-bearing fixed-flexion posteroanterior knee radiographs to determine joint space width (JSW) and Kellgren-Lawrence (KL) grades. Joint space narrowing (JSN) was determined as JSW change from 0 to 24 months. Twenty-seven subjects underwent baseline contrast-enhanced 3T knee MRI for synovial volume (SV) assessment. RESULTS: sUA correlated with JSN in both univariate (r=0.40, p/=6.8; JSN of 0.31 mm for sUA<6.8, p<0.01). Baseline sUA distinguished progressors (JSN>0.2mm) and fast progressors (JSN>0.5mm) from nonprogressors (JSN