Laurence Parker

Accuracy of MRI, MR Arthrography, and Ultrasound in the Diagnosis of Rotator Cuff Tears: A Meta-Analysis

OBJECTIVE The purpose of this study was to compare the diagnostic accuracy of MRI, MR arthrography, and ultrasound for the diagnosis of rotator cuff tears through a meta-analysis of the studies in the literature. MATERIALS AND METHODS Articles reporting the sensitivities and specificities of MRI, MR arthrography, or ultrasound for the diagnosis of rotator cuff tears were identified. Surgical (open and arthroscopic) reference standard was an inclusion criterion. Summary statistics were generated using pooled data. Scatterplots of the data sets were plotted on a graph of sensitivity versus (1 - specificity). Receiver operating characteristic (ROC) curves were generated. RESULTS Sixty-five articles met the inclusion criteria for this meta-analysis. In diagnosing a full-thickness tear or a partial-thickness rotator cuff tear, MR arthrography is more sensitive and specific than either MRI or ultrasound (p < 0.05). There are no significant differences in either sensitivity or specificity between MRI and ultrasound in the diagnosis of partial- or full-thickness rotator cuff tears (p > 0.05). Summary ROC curves for MR arthrography, MRI, and ultrasound for all tears show the area under the ROC curve is greatest for MR arthrography (0.935), followed by ultrasound (0.889) and then MRI (0.878); however, pairwise comparisons of these curves show no significant differences between MRI and ultrasound (p > 0.05). CONCLUSION MR arthrography is the most sensitive and specific technique for diagnosing both full- and partial-thickness rotator cuff tears. Ultrasound and MRI are comparable in both sensitivity and specificity.

MRI criteria for patella alta and baja

ObjectiveTo determine the range of the patellar tendon length to patellar length ratio on magnetic resonance imaging (MRI) of the knee in order to aid in the establishment of MRI criteria for patella alta and baja.PatientsTwo hundred and forty-five patients ages 6–85 (mean 44) years who went through 262 consecutive 1.5 MRI studies of the knee performed during November 2000 through February 2001 were evaluated, regardless of their clinical symptoms.DesignPatellar length (PL) and patellar tendon length (TL) were measured by a single musculoskeletal radiologist on sagittal images by a line connecting the superior and inferior patellar poles and the shortest length of the inner margin of the tendon respectively. TL/PL ratio was subsequently calculated. The distribution of ratios was evaluated; the extreme 2.5% at each end of the distribution was defined as patella alta and baja.ResultsThe TL/PL ratio ranged between 0.56 and 1.71 (mean 1.05). After plotting the ratios, we noted an asymmetric curve skewed to the left. Based upon calculation of the extreme 2.5% of the ratio at each end of the plot, we determined that the MRI definition of patella alta and baja is a ratio of TL/PL of more than 1.50 and less than 0.74 respectively. We found that females had significantly higher TL/PL ratio than males (1.0878 and 1.0032 respectively). Ratios defined for patella alta and baja were 1.52 and 0.79 respectively in females and 1.32 and 0.74 respectively in males (p<0.0001).ConclusionPatella alta and baja are determined as TL/PL of more than 1.50 and less than 0.74 respectively, somewhat different than traditionally quoted radiographic and previously described MRI criteria.

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 years 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

Bending the Curve: The Recent Marked Slowdown in Growth of Noninvasive Diagnostic Imaging

3.6 billion, of which

Trends in Utilization Rates of the Various Imaging Modalities in Emergency Departments: Nationwide Medicare Data From 2000 to 2008

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

Functional magnetic resonance cholangiography (fMRC) of the gallbladder and biliary tree with contrast-enhanced magnetic resonance cholangiography

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.

Geographic Variation in the Utilization of Noninvasive Diagnostic Imaging: National Medicare Data, 1998–2007

OBJECTIVE The purpose of this article is to determine whether there has been any change in the rapid growth pattern that has characterized noninvasive diagnostic imaging in recent years. MATERIALS AND METHODS The annual nationwide Medicare Part B databases were used. All Current Procedural Terminology codes for discretionary noninvasive diagnostic imaging were identified. The overall utilization rates per 1,000 fee-for-service beneficiaries were calculated from 1998 through 2008, as were rates by modality. Determination was made as to whether studies were interpreted by radiologists or nonradiologist physicians. RESULTS The total utilization rate of noninvasive diagnostic imaging grew at a compound annual growth rate of 4.1% from 1998 to 2005, but this decreased to 1.4% from 2005 to 2008. From 2005 through 2008, the overall growth trends flattened dramatically for MRI and nuclear medicine and abated somewhat for CT, ultrasound, and echocardiography. In ambulatory settings, flattening of the advanced imaging growth curves was seen in both private offices and hospital outpatient facilities. From 1998 to 2005, the compound annual growth rate was 3.4% among radiologists and 6.6% among nonradiologist physicians. From 2005 to 2008, the compound annual growth rate decreased to 0.8% among radiologists and 1.8% among nonradiologists. CONCLUSION There has been a distinct slowing in the growth of discretionary noninvasive diagnostic imaging in the Medicare fee-for-service population since 2005. The slowdown has been most pronounced in MRI and nuclear medicine. This should allay some of the concerns of policymakers and payers. Both before and after 2005, growth was approximately twice as rapid among nonradiologist physicians as among radiologists.

Lumbar interspinous bursitis (Baastrup disease) in a symptomatic population: prevalence on magnetic resonance imaging.

PURPOSE To study utilization trends in the various imaging modalities in emergency departments (EDs) over a recent multiyear period. METHODS The nationwide Medicare Part B databases for 2000 to 2008 were queried. Medicares location codes were used to identify imaging examinations done on ED patients. All diagnostic imaging Current Procedural Terminology(®) codes were grouped by modality. For each code, the database provides procedure volume; utilization rates per 1,000 beneficiaries were then calculated. Medicares physician specialty codes were used to determine provider specialty. Utilization trends were studied between 2000 and 2008. RESULTS The overall utilization rate per 1,000 beneficiaries for all imaging in EDs increased from 281.0 in 2000 to 450.4 in 2008 (+60%). The radiography utilization rate rose from 227.3 in 2000 to 294.3 in 2008 (+29%, 67 accrued new studies per 1,000). The CT rate rose from 40.0 in 2000 to 130.7 in 2008 (+227%, 90.7 accrued new studies per 1,000). The ultrasound rate rose from 9.6 in 2000 to 18.7 in 2008 (+95%, 9.1 accrued new studies per 1,000). Other modalities had much lower utilization. In 2000, CT constituted 14% of all ED imaging, but by 2008, it constituted 29%. In 2008, radiologists performed 96% of all ED imaging examinations. CONCLUSIONS The rate of utilization of imaging is increasing in EDs. Growth is by far the most pronounced in CT, in terms of both the growth rate itself and the actual number of accrued new studies per 1,000 beneficiaries. Radiologists strongly predominate as the physicians of record for all ED imaging.

The Recent Downturn in Utilization of CT: The Start of a New Trend?

To determine the diagnostic performance of functional magnetic resonance cholangiography (fMRC) for the evaluation of anatomic and functional biliary disorders.

Suspected early or mild chronic pancreatitis: Enhancement patterns on gadolinium chelate dynamic MRI

OBJECTIVE This study provides an overview of geographic variation in noninvasive diagnostic imaging utilization in the Medicare population over the period 1998 to 2007. MATERIALS AND METHODS The Centers for Medicare and Medicaid Services Physician Supplier Procedure Summary Master Files for 1998-2007 were the primary data source for the study. Physician Supplier Procedure Summary Master Files are an aggregation of the complete Part B Medicare billing records for all 32-37 million fee-for-service beneficiaries and provide the total number of each type of procedure performed, categorized by geographic regions. For the 10 Centers for Medicare and Medicaid Services geographic regions, we calculated the overall noninvasive diagnostic imaging procedure utilization rate and the ratio of the highest to lowest region (a relative risk statistic) for each year of the study. For the first and last years of the study, we calculated these numbers for 28 noninvasive diagnostic imaging categories. RESULTS In 2007, the Atlanta region had the highest utilization rate, with 4.60 procedures per capita, and Seattle had the lowest rate, with 2.99 procedures per capita. The relative risk was 1.54. Over the 10 years of the study, there was little change in the relative utilization rates of regions, and the relative risk ranged between 1.47 and 1.56. In 2007, bone densitometry showed the lowest regional relative risk (1.29), and cardiovascular PET showed the highest regional relative risk (70.2). Cardiovascular noninvasive diagnostic imaging and high-technology, high-cost noninvasive diagnostic imaging (e.g., MRI, PET, and nuclear medicine) showed high regional relative risk. CONCLUSION Regional variation is substantial--about 50% higher in the highest regions than in the lowest regions--but is not huge. Regional variation is increasing slightly. Cardiovascular and high-technology procedures show the greatest regional variation.