Reliability assessment of the OMERACT whole-body magnetic resonance imaging scoring system for juvenile idiopathic arthritis.

Inter-reader reliability of a new scoring system for evaluating joint inflammation and enthesitis in whole body MRI (WBMRI) in juvenile idiopathic arthritis was tested. The scoring system grades 732 item-region combinations of bone marrow and soft tissue changes for commonly involved joints and entheseal sites. Five radiologists rated 17 WBMRI scans through an online rating platform. Item-wise reliability was calculated for 117 items with non-zero scores in >10 % of readings. Interquartile ranges of the five-reader Kappa reliability coefficients were 0.58-0.73 (range: 0.36-0.88) for the joints, 0.65-0.81 (range: 0.39-0.95) for the entheses, and 0.62-0.75 (range: 0.60-0.76) for chronic nonbacterial osteomyelitis-like lesions.

Quantitative CT for Preoperative Assessment of Lumbar Degenerative Spondylolisthesis: The Unique Impact of L4 Bone Mineral Density on Single-Level Disease.

Background: Quantitative computed tomography (qCT) efficiently measures 3-dimensional vertebral bone mineral density (BMD), but its utility in measuring BMD at various vertebral levels in patients with lumbar degenerative spondylolisthesis (LDS) is unclear. Purpose: We sought to determine whether qCT could differentiate BMD at different levels of LDS, particularly at L4-L5, the most common single level for LDS. In addition, we sought to describe patterns of BMD for single-level and multiple-level LDS. Methods: We conducted a study of patients undergoing surgery for LDS who were part of a larger longitudinal study comparing preoperative and intraoperative images. Preoperative patients were grouped as single-level or multiple-level LDS, and qCT BMD was obtained for L1-S1 vertebrae. Mean BMD was compared with literature reports; in multivariable analyses, BMD of each vertebra was assessed according to the level of LDS, controlling for covariates and for BMD of other vertebrae. Results: Of 250 patients (mean age: 67 years, 64% women), 22 had LDS at L3-L4 only, 170 at L4-L5 only, 13 at L5-S1 only, and 45 at multiple levels. Compared with other disorders reported in the literature, BMD in our sample similarly decreased from L1 to L3 then increased from L4 to S1, but mean BMD per vertebra in our sample was lower. Nearly half of our sample met criteria for osteopenia. In multivariable analysis controlling for BMD at other vertebrae, lower L4 BMD was associated with LDS at L4-L5, greater pelvic incidence minus lumbar lordosis, and not having diabetes. In contrast, in similar multivariable analysis, greater L4 BMD was associated with LDS at L3-L4. Bone mineral density of L3 and L5 was not associated with LDS levels. Conclusion: In our sample of preoperative patients with LDS, we observed lower BMD for LDS than for other lumbar disorders. L4 BMD varied according to the level of LDS after controlling for covariates and BMD of other vertebrae. Given that BMD can be obtained from routine imaging, our findings suggest that qCT data may be useful in the comprehensive assessment of and strategy for LDS surgery. More research is needed to elucidate the cause-effect relationships among spinopelvic alignment, LDS, and BMD.

Preoperative MRI-based vertebral bone quality (VBQ) score assessment in patients undergoing lumbar spinal fusion.

BACKGROUND CONTEXT: The importance of bone status assessment in spine surgery is well recognized. The current gold standard for assessing bone mineral density is dual-energy X-ray absorptiometry (DEXA). However, DEXA has been shown to overestimate BMD in patients with spinal degenerative disease and obesity. Consequently, alternative radiographic measurements using data routinely gathered during preoperative evaluation have been explored for the evaluation of bone quality and fracture risk. Opportunistic quantitative computed tomography (QCT) and more recently, the MRI-based vertebral bone quality (VBQ) score, have both been shown to correlate with DEXA T-scores and predict osteoporotic fractures. However, to date the direct association between VBQ and QCT has not been studied. PURPOSE: The objective of this study was to evaluate the correlation between VBQ and spine QCT BMD measurements and assess whether the recently described novel VBQ score can predict the presence of osteopenia/osteoporosis diagnosed with QCT. STUDY DESIGN/SETTING: Cross-sectional study using retrospectively collected data. PATIENT SAMPLE: Patients undergoing lumbar fusion from 2014-2019 at a single, academic institution with available preoperative lumbar CT and T1-weighted MRIs were included. OUTCOME MEASURES: Correlation of the VBQ score with BMD measured by QCT, and association between VBQ score and presence of osteopenia/osteoporosis. METHODS: Asynchronous QCT measurements were performed. The average L1-L2 BMD was calculated and patients were categorized as either normal BMD (>120 mg/cm3) or osteopenic/osteoporotic (≤120 mg/cm3). The VBQ score was calculated by dividing the median signal intensity of the L1-L4 vertebral bodies by the signal intensity of the cerebrospinal fluid on midsagittal T1-weighted MRI images. Inter-observer reliability testing of the VBQ measurements was performed. Demographic data and the VBQ score were compared between the normal and osteopenic/osteoporotic group. To determine the area-under-curve (AUC) of the VBQ score as a predictor of osteopenia/osteoporosis receiver operating characteristic (ROC) analysis was performed. VBQ scores were compared with QCT BMD using the Pearson's correlation. RESULTS: A total of 198 patients (53% female) were included. The mean age was 62 years and the mean BMI was 28.2 kg/m2. The inter-observer reliability of the VBQ measurements was excellent (ICC of 0.90). When comparing the patients with normal QCT BMD to those with osteopenia/osteoporosis, the patients with osteopenia/osteoporosis were significantly older (64.9 vs. 56.7 years, p<.0001). The osteopenic/osteoporotic group had significantly higher VBQ scores (2.6 vs. 2.2, p<.0001). The VBQ score showed a statistically significant negative correlation with QCT BMD (correlation coefficient = -0.358, 95% CI -0.473 - -0.23, p<.001). Using a VBQ score cutoff value of 2.388, the categorical VBQ score yielded a sensitivity of 74.3% and a specificity of 57.0% with an AUC of 0.7079 to differentiate patients with osteopenia/osteoporosis and with normal BMD. CONCLUSIONS: We found that the VBQ score showed moderate diagnostic ability to differentiate patients with normal BMD versus osteopenic/osteoporotic BMD based on QCT. VBQ may be an interesting adjunct to clinically performed bone density measurements in the future.

MRI Assessment of Sacroiliitis With High-Resolution Protocol.

Background: Sacroiliac (SI) joint subchondral resorption on high-resolution magnetic resonance imaging (MRI) may be an early sign of the development of sacroiliitis. At our institution, high-resolution intermediate-weighted (proton density) MRI sequences are used in the workup of suspected spondyloarthritis (SpA). Questions/Purpose: We sought to test the hypothesis that SI joint subchondral resorption might be a useful MRI feature in the diagnosis of sacroiliitis. Methods: We retrospectively reviewed the records of patients with suspected SpA from a single rheumatologist's practice from January 1, 2010, to December 31, 2017. Patients had an MRI of the SI joints, using our institution's specialized protocol, and underwent standard physical examination and laboratory evaluation. The sensitivity and specificity of SI joint subchondral resorption in the identification of sacroiliitis were estimated using the clinical diagnosis as the reference standard and from a Bayesian latent class model with conditional dependence. Results: SI joint subchondral resorption on SI joint MRI was highly correlated with a positive diagnosis in patients worked up for axial SpA. It demonstrated superior sensitivity when compared with other MRI features used in the MRI diagnosis of sacroiliitis, such as bone marrow edema pattern, erosion, and ankylosis. Interobserver reliability was high for subchondral resorption. Conclusion: This retrospective study found that subchondral resorption on MRI evaluation of the SI joints appeared to be a sensitive indicator of SpA, potentially of early disease. This imaging feature warrants evaluation in other cohorts of patients suspected of having axial SpA to validate diagnostic performance in diverse populations.

Consensus-driven conceptual development of a standardized whole body-MRI scoring system for assessment of disease activity in juvenile idiopathic arthritis: MRI in JIA OMERACT working group.

OBJECTIVES: Whole body-MRI is helpful in directing diagnostic and treatment approaches, and as a research outcome measure. We describe our initial consensus-driven phase towards developing a whole body-MRI scoring system for juvenile idiopathic arthritis. METHODS: An iterative approach using three rounds of anonymous Delphi surveys followed by a consensus meeting was used to draft the structure of the whole body-MRI scoring system, including the relevant anatomic joints and entheses for assessment, diagnostic item selection, definition and grading, and selection of appropriate MRI planes and sequences. The surveys were completed independently by an international expert group consisting of pediatric radiologists and rheumatologists. RESULTS: Twenty-two experts participated in at least one of three rounds of Delphi surveys and a concluding consensus meeting. A first iteration scoring system was developed which ultimately included the assessment of 100 peripheral, 23 chest, and 76 axial joints, and 64 entheses, with 2-4 diagnostic items graded in each of the items, using binary (presence/absence) and 2-3-level ordinal scores. Recommendations on anatomic MRI planes and sequences were specified as the minimally necessary imaging protocol for the scoring system. CONCLUSION: A novel whole body-MRI scoring system for juvenile idiopathic arthritis was developed by consensus among members of MRI in JIA OMERACT working group. Further iterative refinements, reliability testing, and responsiveness are warranted in upcoming studies.

Radiation safety and knowledge: an international survey of 708 interventional pain physicians.

INTRODUCTION: Interventional pain procedures have increased in complexity, often requiring longer radiation exposure times and subsequently higher doses. The practicing physician requires an in-depth knowledge and evidence-based knowledge of radiation safety to limit the health risks to themselves, patients and healthcare staff. The objective of this study was to examine current radiation safety practices and knowledge among interventional pain physicians and compare them to evidence-based recommendations. MATERIALS AND METHODS: A 49-question survey was developed based on an extensive review of national and international guidelines on radiation safety. The survey was web-based and distributed through the following professional organizations: Association of Pain Program Directors, American Academy of Pain Medicine, American Society of Regional Anesthesia and Pain Medicine, European Society of Regional Anesthesia and Pain Therapy, International Neuromodulation Society, and North American Neuromodulation Society. Responses to radiation safety practices and knowledge questions were evaluated and compared with evidence-based recommendations. An exploratory data analysis examined associations with radiation safety training/education, geographical location, practice type, self-perceived understanding, and fellowship experience. RESULTS: Of 708 responding physicians, 93% reported concern over the health effects of radiation, while only 63% had ever received radiation safety training/education. Overall, ≥80% physician compliance with evidence-based radiation safety practice recommendations was demonstrated for only 2/15 survey questions. Physician knowledge of radiation safety principles was low, with 0/10 survey questions having correct response rates ≥80%. CONCLUSION: We have identified deficiencies in the implementation of evidence-based practices and knowledge gaps in radiation safety. Further education and training are warranted for both fellowship training and postgraduate medical practice. The substantial gaps identified should be addressed to better protect physicians, staff and patients from unnecessary exposure to ionizing radiation during interventional pain procedures.

Vertebroplasty and kyphoplasty in the USA from 2004 to 2017: national inpatient trends, regional variations, associated diagnoses, and outcomes.

BACKGROUND: To explore the national inpatient trends, regional variations, associated diagnoses, and outcomes of vertebral augmentation (vertebroplasty and kyphoplasty) in the USA from 2004 to 2017. METHODS: Data from the National Inpatient Sample were used to study hospitalization records for percutaneous vertebroplasty and kyphoplasty. Longitudinal projections of trends and outcomes, including mortality, post-procedural complications, length of stay, disposition, and total hospital charges were analyzed. RESULTS: Following a period of decreased utilization from 2008 to 2012, hospitalizations for vertebroplasty and kyphoplasty plateaued after 2013. Total hospital charges and overall financial burden of hospitalizations for vertebroplasty and kyphoplasty increased to a peak of $1.9 billion (range $1.7-$2.2 billion) in 2017. Overall, 8% of procedures were performed in patients with a history of malignancy. In multivariable modeling, lung cancer (adjusted OR (aOR) 2.6 (range 1.4-5.1)) and prostate cancer (aOR 3.4 (range 1.2-9.4)) were associated with a higher risk of mortality. The New England region had the lowest frequency of routine disposition (14.1±1.1%) and the lowest average hospital charges ($47 885±$1351). In contrast, 34.0±0.8% had routine disposition in the West Central South region, and average hospital charges were as high as $99 836±$2259 in the Pacific region. The Mountain region had the lowest number of procedures (5365±272) and the highest mortality rate (1.2±0.3%). CONCLUSION: National inpatient trends of vertebroplasty and kyphoplasty utilization remained stable after a period of decline from 2008 to 2012, while the financial burden of hospitalizations increased. Despite recent improvements in outcomes, significant regional variations persisted across the USA.

Assessment of Loosening and Rotational Malalignment Following Knee Endoprosthesis or Other Surgical Components.

Total knee arthroplasty (TKA) has significant medical and economic implications. The correct placement of the femoral and tibial components is vital to ensure a functional knee and also low failure and revision surgery rates. This article provides the most relevant information regarding knee endoprosthesis from a radiologic point of view. Basic information on the recommended alignment of the femoral and tibial components in TKA and how to measure them are discussed. We then present the most important axial plane rotational references for the femoral and the tibial components. The optimal coronal alignment, illustrating the axes of the lower limb, and loosening as the major complication are also discussed. Finally, we offer a detailed example of rotational assessment.

Quality Measurements in Radiology: A Systematic Review of the Literature and Survey of Radiology Benefit Management Groups.

PURPOSE: As the US health care system transitions toward value-based reimbursement, there is an increasing need for metrics to quantify health care quality. Within radiology, many quality metrics are in use, and still more have been proposed, but there have been limited attempts to systematically inventory these measures and classify them using a standard framework. The purpose of this study was to develop an exhaustive inventory of public and private sector imaging quality metrics classified according to the classic Donabedian framework (structure, process, and outcome). METHODS: A systematic review was performed in which eligibility criteria included published articles (from 2000 onward) from multiple databases. Studies were double-read, with discrepancies resolved by consensus. For the radiology benefit management group (RBM) survey, the six known companies nationally were surveyed. Outcome measures were organized on the basis of standard categories (structure, process, and outcome) and reported using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. RESULTS: The search strategy yielded 1,816 citations; review yielded 110 reports (29 included for final analysis). Three of six RBMs (50%) responded to the survey; the websites of the other RBMs were searched for additional metrics. Seventy-five unique metrics were reported: 35 structure (46%), 20 outcome (27%), and 20 process (27%) metrics. For RBMs, 35 metrics were reported: 27 structure (77%), 4 process (11%), and 4 outcome (11%) metrics. The most commonly cited structure, process, and outcome metrics included ACR accreditation (37%), ACR Appropriateness Criteria (85%), and peer review (95%), respectively. CONCLUSIONS: Imaging quality metrics are more likely to be structural (46%) than process (27%) or outcome (27%) based (P < .05). As national value-based reimbursement programs increasingly emphasize outcome-based metrics, radiologists must keep pace by developing the data infrastructure required to collect outcome-based quality metrics.

Sclerotic lesions of the spine: MRI assessment.

Sclerotic (T2 dark) lesions of the spine are infrequent and, as a result, these are often missed or misdiagnosed. Plain films may not be always available during magnetic resonance imaging (MRI) readout. Knowledge of such lesions and their imaging appearances on MRI evaluation is essential for a reader. Additionally, a systematic approach is important to accurately diagnose these lesions. In this article we discuss the various causes of spinal sclerotic lesions, describe their MRI characteristics with relevant case examples, and outline a systematic approach to their evaluation.

Radiology fellowship with a focus on musculoskeletal imaging: current challenges and future directions.

OBJECTIVE: Many musculoskeletal fellowships are nonaccredited, leading to heterogeneity of educational experiences. There is no governing body for these nonaccredited fellowships, leaving program content and rules to the program directors' discretion. In addition, imaging fellowships in general currently face many external pressures that challenge their capacity to provide a high-quality education. Federal cuts to Medicare, diminished reimbursement to radiology departments, and pressure for increased accountability exerted by insurance companies and hospitals all place additional stress on fellowship training programs. CONCLUSION: Only those fellowships providing the highest-quality educational experience will continue to thrive.

Magnetic resonance imaging of musculoskeletal infections: systematic diagnostic assessment and key points.

Prompt diagnosis and treatment are essential in preventing the complications of musculoskeletal infection. In this context, imaging is often used to confirm clinically suspected diagnoses, define the extent of infection, and ensure appropriate management. Because of its superior soft-tissue contrast resolution, magnetic resonance imaging (MRI) is the modality of choice for evaluating musculoskeletal infections. This article describes the MRI features along the full spectrum of musculoskeletal infections and provides several illustrative case examples.

Augmented reality visualization with use of image overlay technology for MR imaging-guided interventions: assessment of performance in cadaveric shoulder and hip arthrography at 1.5 T.

PURPOSE: To prospectively assess overlay technology in providing accurate and efficient targeting for magnetic resonance (MR) imaging-guided shoulder and hip joint arthrography. MATERIALS AND METHODS: A prototype augmented reality image overlay system was used in conjunction with a clinical 1.5-T MR imager. A total of 24 shoulder joint and 24 hip joint injections were planned in 12 human cadavers. Two operators (A and B) participated, each performing procedures on different cadavers using image overlay guidance. MR imaging was used to confirm needle positions, monitor injections, and perform MR arthrography. Accuracy was assessed according to the rate of needle adjustment, target error, and whether the injection was intraarticular. Efficiency was assessed according to arthrography procedural time. Operator differences were assessed with comparison of accuracy and procedure times between the operators. Mann-Whitney U test and Fisher exact test were used to assess group differences. RESULTS: Forty-five arthrography procedures (23 shoulders, 22 hips) were performed. Three joints had prostheses and were excluded. Operator A performed 12 shoulder and 12 hip injections. Operator B performed 11 shoulder and 10 hip injections. Needle adjustment rate was 13% (six of 45; one for operator A and five for operator B). Target error was 3.1 mm±1.2 (standard deviation) (operator A, 2.9 mm±1.4; operator B, 3.5 mm±0.9). Intraarticular injection rate was 100% (45 of 45). The average arthrography time was 14 minutes (range, 6-27 minutes; 12 minutes [range, 6-25 minutes] for operator A and 16 minutes [range, 6-27 min] for operator B). Operator differences were not significant with regard to needle adjustment rate (P=.08), target error (P=.07), intraarticular injection rate (P>.99), and arthrography time (P=.22). CONCLUSION: Image overlay technology provides accurate and efficient MR guidance for successful shoulder and hip arthrography in human cadavers.

Proton MR spectroscopy in metabolic assessment of musculoskeletal lesions.

OBJECTIVE: The purposes of this review are to describe the principles and method of MR spectroscopy, summarize current published data on musculoskeletal lesions, and report additional cases that have been analyzed with recently developed quantitative methods. CONCLUSION: Proton MR spectroscopy can be used to identify key tissue metabolites and may serve as a useful adjunct to radiographic evaluation of musculoskeletal lesions. A pooled analysis of 122 musculoskeletal tumors revealed that a discrete choline peak has a sensitivity of 88% and specificity of 68% in the detection of malignancy. Modest improvements in diagnostic accuracy in 22 of 122 cases when absolute choline quantification was used encourage the pursuit of development of choline quantification methods.

Recognition, assessment, and treatment of non-union after surgical fixation of fractures: emphasis on 3D CT.

For the post-operative patient, conventional axial computed tomography (CT) imaging and 2D multiplanar reconstruction are of limited value because of the beam-hardening artifact. However, three-dimensional (3D) CT imaging is an effective means of detecting subtle fracture healing, or confirming non-union, and for evaluating the integrity of metal hardware. In this article we emphasize the advantages of 3D CT imaging in the assessment and preoperative planning of non-union for patients who have been surgically treated for fractures.

Musculoskeletal imaging: medicare use, costs, and potential for cost substitution.

PURPOSE: The current study explores the substitution of ultrasound (US) for magnetic resonance imaging (MRI) of musculoskeletal (MSK) disorders by describing the recent use and costs of MSK imaging in the Medicare population, projecting these trends from 2006 to 2020, and estimating cost-savings involved in substituting MSK US for MSK MRI, when appropriate. METHODS: The study used government-published data sets and de-identified Radiology Information System records exempt from institutional review board approval. From 1 year's MSK MRI records (n = 3,621), the proportion of cases in which US could be substituted for MRI was estimated. The use rates for 4 modalities of MSK imaging and average costs were determined from government Medicare data sets from 1996 to 2005. Regression analysis was used to project use rates from 2006 to 2020. The effect on costs of substitution was calculated. RESULTS: For the Medicare population, although there has been a moderate overall increase (25.7%) in MSK imaging, MSK MRI has increased 353.5% from 1996 to 2005. Projected MSK imaging costs in 2020 are $3.6 billion, of which $2.0 billion will be for MRI. A study of 3,621 MSK MRI reports indicates that 45.4% of primary diagnoses and 30.6% of all diagnoses could have been made with MSK US. The substitution of MSK US for MSK MRI, when appropriate, would lead to savings of more than $6.9 billion in the period from 2006 to 2020. CONCLUSION: MRI MSK use has grown substantially from 1996 to 2005. The substitution of MSK US, when appropriate, would lead to large cost-savings for Medicare.

Vertebroplasty in the United States: guidance method and provider distribution, 2001-2003.

PURPOSE: To use the nationwide Medicare database to retrospectively evaluate the provider distribution for vertebroplasty, as well as the guidance method used in the United States. MATERIALS AND METHODS: Use of the Medicare database was exempt from Institutional Review Board review and informed consent; regarding HIPAA compliance, the Medicare database lacks unique patient identifiers. Using the 2001, 2002, and 2003 United States Medicare part B claims database, the authors studied CPT-4 (Current Procedural Terminology, fourth edition) procedure codes used for vertebroplasty procedures, including thoracic and lumbar vertebroplasty (22520 and 22521, respectively), treatment of additional levels (22522), and method of radiologic guidance (fluoroscopy, 76012; CT, 76013). For each of these codes, volume and physician specialty participation were tabulated. RESULTS: In 2001, 14 152 vertebroplasty procedures were reimbursed through Medicare. In 2003, the volume increased to 24 558 (+73.5%). In 2001 radiologists performed the majority (9864, 69.7%) of these procedures. The minority were performed by other specialists, mainly orthopedic surgeons (1792, 12.7%), neurosurgeons (1037, 7.3%) and anesthesiologists (736, 5.2%). In 2003, radiologists performed 86.8% more vertebroplasties than in 2001, and participation increased to 75.0% of the total. Radiologists had the greatest increase of all specialties from 2001 to 2003 (+86.8% vs: orthopedic surgery, +58.3%; neurosurgery, +55.7%; other, +46.6%; physiatry, +32.1%; neurology, +15.5%; anesthesiology, -11.8%). From 2001 to 2003, the number of additional levels treated by each of the three highest-volume specialties decreased (radiology, 23.0% to 20.8%; orthopedic surgery, 36.3% to 27.5%; neurosurgery, 28.2% to 27.0%). As a guidance method, fluoroscopy is used almost exclusively (98.7% in 2003). CONCLUSION: Radiologists performed the majority of Medicare-reimbursed vertebroplasty procedures in the United States in 2001-2003. Fluoroscopy is nearly universal as a guidance method.

Percutaneous vertebroplasty among low income Medicare beneficiaries.

STUDY DESIGN: Cohort. OBJECTIVE: To assess the patterns and predictors of percutaneous vertebroplasty use among low-income Medicare beneficiaries from 1 U.S. state. SUMMARY OF BACKGROUND DATA: Many observational studies have examined the effectiveness of vertebroplasty, but none has described its pattern of use in the community. METHODS: We studied a cohort of low-income Medicare beneficiaries from Pennsylvania diagnosed with a spine fracture between 2001 and 2004. Healthcare utilization data were assessed to determine receipt of a vertebroplasty. The frequency of vertebroplasty among spine fracture patients was examined by year and by county of residence. Multivariable logistic regression models were constructed to identify correlates of receiving a vertebroplasty. RESULTS: We found 6392 patients who fulfilled our criteria for a spine fracture. Of these, 459 (7.2%) underwent a vertebroplasty in the subsequent 12 months. The percent of patients sustaining a fracture who underwent vertebroplasty increased from 6.8% to 8.2%, a 20% increase, over the 4-year study period. Substantial variation in use of vertebroplasty was observed across county of patient residence, with several counties having zero patients and many with >15% undergoing vertebroplasty. Several patient factors predicted use of vertebroplasty, including age 65 to 84 years (compared with 85 years and older), and more physician visits in the 12 months before the spine fracture. The model fit statistic (C statistic) for models with only patient factors was weak (c = 0.60), but this increased substantially when county of residence was also included in the model (c = 0.72). CONCLUSION: Vertebroplasty use has generally increased over the study period. Patient characteristics determined from healthcare utilization data are weak correlates of vertebroplasty use, but a patient's county of residence is a relatively strong predictor.

Trends in utilization: has extremity MR imaging replaced diagnostic arthroscopy?

OBJECTIVE: To examine the relative change in utilization of magnetic resonance (MR) imaging of the extremities versus diagnostic and therapeutic arthroscopy. DESIGN AND PATIENTS: Using the 1993, 1996, and 1999 nationwide Medicare Part B databases, utilization rates (per 100000) were determined for upper and lower extremity MR imaging, diagnostic arthroscopy and therapeutic arthroscopy using CPT-4 codes. Utilization of extremity MR imaging was compared with that of diagnostic and therapeutic arthroscopy in 10 geographic regions of the United States and tracked over time. RESULTS: Combined lower and upper extremity MR imaging utilization per 100000 increased from 393 to 1056 in 1999 (+168.7%). Utilization of diagnostic arthroscopy of the extremities decreased from 18 in 1993 to 8 in 1999 (-55.6%); therapeutic arthroscopy rates increased from 461 in 1993 to 636 in 1999 (+40.0%). Specifically, from 1993 to 1999, utilization of lower extremity MR imaging increased from 270 to 661 (+144.8%). Utilization of diagnostic arthroscopy of the knee over the same time period decreased from 11 to 5 (-54.5%); therapeutic arthroscopy increased from 394 to 501 (+27.2%). Similarly, utilization rates for upper extremity MR imaging increased from 123 to 395 (+221.1%). Utilization of diagnostic arthroscopy of the shoulder over the same time period decreased from 7 to 2 (-71.4%); therapeutic arthroscopy increased from 44 to 104 (+136.4%). No specific geographic trends were ascertained. CONCLUSION: The utilization of MR imaging of the extremities has markedly increased from 1993 to 1999. During the same time period the utilization of diagnostic arthroscopy has decreased and that of therapeutic arthroscopy has increased. These findings support the hypothesis that there is increased reliance of clinical practitioners on the diagnostic information provided by MR imaging in preoperative clinical decision-making.

Trends in knee magnetic resonance imaging.

OBJECTIVE: To assess trends in knee magnetic resonance imaging (MRI) use and accompanying management changes to determine whether indications for this test have changed over time. DATA SOURCES: Large administrative database containing health care information for 587,010 people living in 1 state who were enrolled in the Medicare or Medicaid programs. They all had used health services during 3 consecutive years between 1991 to 1995. METHODS: We performed a retrospective cohort study examining the rates of lower extremity MRI in successive years and calculated the proportion of patients who were seen by a knee specialist or underwent knee surgery subsequent to the MRI. RESULTS: The annual rate of knee MRI was 1.4 per 1000 person-years in 1991 and increased by 140% to 3.4 per 1000 person-years by 1995 (P = 0.001). Approximately half of patients who underwent a knee MRI in 1991 had a diagnosis of internal derangement of the knee in the prior year; this figure dropped to 35% in 1995 (P < 0.001). The percentage of patients undergoing a knee MRI who had no record of any knee diagnosis in the prior year grew from 13% in 1991 to 33% in 1995 (P < 0.001). Over the 5 years of the study, the percentage of patients whose knee MRI was followed by specialist care or knee surgery decreased from 68% to 58%, a relative change of 15% (P < 0.005). CONCLUSION: Knee MRI use increased sharply during the study period, but the proportion of such patients who had a prior diagnosis of internal derangement or subsequently saw a knee specialist or underwent knee surgery decreased. This finding indicates that the criteria for knee MRI appear to have broadened substantially during this period.