Association between Medicaid expansion status and lung cancer screening exam growth: findings from the ACR lung cancer registry.

PURPOSE: To determine if Medicaid expansion is associated with increased volumes of lung cancer screenings. METHODS: A quasi-experimental study was performed to compare the annual growth rates in lung cancer screenings between states that expanded Medicaid (n = 31) versus those that did not (n = 17). Using the American College of Radiology Lung Cancer Screening Registry, we calculated the average annual growth rate between 2016 and 2019 for both groups. Secondary analyses between these two groups also included calculations of the percentages of studies considered appropriate by USPSTF criteria. RESULTS: No significant difference was identified in the average annual growth in lung cancer screenings between Medicaid expanding and non-expanding states (57.6%, 50.3%, P = 0.51). No difference was observed in the percentage of studies considered appropriate (Medicaid expanding = 89.6%, non-expanding = 90.2%, P = 0.72). At baseline, there were socioeconomic differences between both groups of states. Medicaid expanding states had a more urban population (76.5% versus 67.9%, P = 0.05) and higher average incomes ($56,947, $49,876, P < 0.05). CONCLUSION: No association is found between Medicaid expansion and increasing volumes of lung cancer screening exams. Although no data is available in the registry for screening exams before the implementation of Medicaid expansion (2014), most nationwide estimates of lung screening rates report a low baseline (<5%). Furthermore, despite being advantaged in other ways, such as with a more urban population or with higher incomes, the Medicaid expansion cohort does not demonstrate a higher growth rate. These findings suggest Medicaid expansion alone will not increase lung cancer screenings.

Coronary CT Angiography: Reversal of Earlier Utilization Trends.

PURPOSE: To assess recent trends in utilization of coronary CT angiography (CCTA), based upon place of service and provider specialty. MATERIALS AND METHODS: The nationwide Medicare Part B master files for 2006 through 2016 were the data source. Current Procedural Terminology, version 4 codes for CCTA were selected. The files provided procedure volume for each code. Utilization rates per 100,000 Medicare fee-for-service enrollees were then calculated. Medicare's place-of-service codes were used to identify CCTAs performed in private offices, hospital outpatient departments (HOPDs), emergency departments (EDs), and inpatient settings. Physician specialty codes were used to identify CCTAs interpreted by radiologists, cardiologists, and all other physicians as a group. Medicare practice share was defined as the percent of total Medicare utilization that was billed by each specialty. RESULTS: The total utilization rate of CCTA in the Medicare population rose sharply from 2006 to 2007, peaking at 210.3 per 100,000 enrollees in 2007. Radiologists' CCTA practice share in 2007 was 32%, compared with 60% for cardiologists. The overall utilization rate then declined to a nadir of 107.1 per 100,000 enrollees in 2013, but subsequently increased to 131.0 by 2016. By that year, radiologists' share of CCTA practice had risen to 58%, compared with 38% for cardiologists. HOPD utilization increased sharply since 2010, primarily among radiologists. In EDs and inpatient settings, greater utilization has also occurred recently, primarily among radiologists. By contrast, private office utilization has dropped sharply since 2007. CONCLUSION: After years of declining utilization, the utilization rate of CCTA is now increasing, predominantly among radiologists.

Coronary CT Angiography: Use in Patients With Chest Pain Presenting to Emergency Departments.

OBJECTIVE: Previously published reports have shown that coronary CT angiography (CCTA) is a more efficient method of diagnosis than myocardial perfusion imaging (MPI) and stress echocardiography for patients presenting to emergency departments (EDs) with acute chest pain. In light of this evidence, the objective of this study was to examine recent trends in the use of these techniques in EDs. MATERIALS AND METHODS: The nationwide Medicare Part B databases for 2006-2015 were the data source. The Current Procedural Terminology, version 4, codes for CCTA, MPI, and stress echocardiography were selected. Medicare place-of-service codes were used to determine procedure volumes in EDs. Medicare specialty codes were used to ascertain how many of these examinations were interpreted by radiologists, cardiologists, and other physicians as a group. RESULTS: From 2006 to 2015, there was essentially no change in the number of MPI examinations performed in EDs for patients using Medicare (22,342 in 2006, 22,338 in 2015) or in the number of stress echocardiograms (3544 in 2006, 3520 in 2015). By contrast, the number of CCTA examinations increased rapidly, from 126 in 2006 to 1919 in 2015 (compound annual growth rate, 35%). Despite this rapid growth, patients in EDs underwent 11.6 times as many MPI as CCTA examinations in 2015. In that last year of the study, radiologists interpreted 78% of ED MPI and 83% of ED CCTA examinations. CONCLUSION: Use of CCTA in EDs has increased rapidly, but far more MPI examinations are still being performed. This finding suggests that recently acquired evidence is not yet being fully acted upon.

Are combined CT scans of the thorax being overused?

PURPOSE: A news article in June 2011 reported that Medicare claims showed considerable overuse of "double" CT scans of the thorax (ie, combined scans without contrast followed by with contrast) at a number of hospitals. Most radiologists agree that they should be done only on rare occasions. The aim of this study was to determine what proportion of all thoracic CT scans are combined scans in the Medicare population. METHODS: The data sources were the Medicare Part B Physician/Supplier Procedure Summary Master Files for 2001 to 2011. The 3 Current Procedural Terminology codes for thoracic CT (with contrast, without contrast, and without plus with contrast) were selected. Utilization rates per 1,000 beneficiaries and the percentage that were combined scans were calculated. RESULTS: The utilization rate of combined scans increased from 2001 through 2006, remained steady in 2007, but then decreased sharply thereafter. The compound annual rate of change from 2007 to 2011 was -10.4%. From 2001 through 2006, combined thoracic CT scans constituted 6.0% to 6.1% of all thoracic CT scans. However, from 2006 to 2011, this percentage progressively declined, reaching a low of 4.2% in 2011. CONCLUSIONS: Despite the 2011 news report, only a very small percentage of thoracic CT scans nationwide are done both without and with contrast. Moreover, that percentage dropped by almost one-third from 2006 to 2011, suggesting that the practice is declining. The figure of 4.2% can be used as a benchmark against which to judge radiology facilities in the future.

The diversion of outpatient echocardiography from private offices to higher cost hospital facilities: an unanticipated effect of code bundling.

PURPOSE: In 2009, the add-on codes for spectral Doppler and color flow Doppler echocardiography were bundled into the code for primary transthoracic echocardiography. The relative value units for the new single code were substantially lower than the previous sum for the 3 codes. The purpose of this study was to see how this affected the distribution of outpatient echocardiographic studies between cardiology offices and hospital outpatient departments (HOPDs). METHODS: The 2005 to 2011 Medicare databases were used. All echocardiography Current Procedural Terminology codes were selected. Specialty codes identified those done by cardiologists (who do most echocardiographic studies). Place-of-service codes identified those done in offices and HOPDs. Procedure volumes and utilization rates per 1,000 were determined each year before and after bundling occurred in 2009. RESULTS: Cardiologists' office echocardiography utilization rate rose from 219.5 per 1,000 in 2005 to 257.1 in 2008 (+17%), then dropped to 100.0 in 2009 (-61%) because of bundling. Their HOPD echocardiography rate rose from 72.2 in 2005 to 76.5 in 2008 (+6%), then dropped to 35.0 in 2009 (-54%). From 2009 to 2011, cardiologists' office echocardiography rate dropped again from 100.0 to 88.8 (-11%), while their HOPD rate increased from 35.0 to 46.1 (+32%). CONCLUSIONS: Echocardiography code bundling produced the expected sharp drop in outpatient claims from cardiologists in 2009. But after bundling, office echocardiography rates continued to drop, while HOPD rates increased. It seems that in this instance, code bundling led to the closure of many cardiology offices and a resultant shift of echocardiography from that lower cost setting to the higher cost HOPD setting.

Bifid median nerve in carpal tunnel syndrome: assessment with US cross-sectional area measurement.

PURPOSE: To evaluate the accuracy of ultrasonography (US) in the diagnosis of carpal tunnel syndrome (CTS) in patients with a bifid median nerve on the basis of cross-sectional area (CSA) measurements of the median nerve at the level of the carpal tunnel (CSAc), with additional measurements obtained more proximally (CSAp) at the level of the pronator quadratus muscle. MATERIALS AND METHODS: This HIPAA-compliant study was approved by the local institutional review board; informed oral and written consent were obtained. Fifty-three wrists in 49 consecutive patients with a bifid median nerve and CTS symptoms and 28 wrists in 27 healthy volunteers with a bifid median nerve were examined by using US. Two independent US examiners who were blinded to prior test results measured median nerve CSA at two levels, CSAc and CSAp. The difference between CSAc and CSAp (ΔCSA) was calculated for each wrist. Receiver operating characteristic (ROC) analysis was performed. RESULTS: The study population included 17 men and 32 women (mean age, 55.1 years; age range, 24-78 years). The control population included 13 men and 14 women (mean age, 52.6 years; age range, 24-86 years). Mean CSAc was approximately 5 mm(2) greater in patients with CTS than in healthy volunteers (P < .0001), while mean ΔCSA was 5.8-5.9 mm(2) greater in patients with CTS (P < .0001). A CSAc threshold of 12 mm(2) provided sensitivity and specificity of 84.9% and 46.5%, respectively, while a ΔCSA threshold of 4 mm(2) provided sensitivity and specificity of 92.5% and 94.6%, respectively. ROC analysis demonstrated a significant advantage of ΔCSA (area under ROC curve [A(z)] = 0.95-0.96) compared with CSAc (A(z) = 0.84-0.85) for the diagnosis of CTS (P < .003). CONCLUSION: The use of a ΔCSA parameter improves the diagnostic accuracy of US for the presence of CTS in patients with a bifid median nerve.

The lack of growth in use of coronary CT angiography: is it being appropriately used?

OBJECTIVE: The purpose of this article is to study recent utilization trends in coronary CT angiography (CTA) and compare them with radionuclide myocardial perfusion imaging (MPI), a competing procedure. MATERIALS AND METHODS: The nationwide Medicare Part B databases were used to determine utilization rates per 100,000 beneficiaries. Rates for coronary CTA were studied from 2006 (the first year Current Procedural Terminology codes were available for this procedure) through 2008. Rates for MPI were studied from 1998 through 2008. Medicare specialty codes were used to identify examinations done by radiologists and cardiologists. RESULTS: The coronary CTA total utilization rate per 100,000 rose from 99 in 2006 to 210 in 2007 (112%) but then decreased to 193 in 2008 (-8%). The rate for MPI increased from 4748 in 1998 to a peak of 8753 in 2006 (84%), then declined to 8467 in 2008. Cardiologists performed the majority of both coronary CTA and MPI. In 2008, MPI was performed 44 times as often as coronary CTA. CONCLUSION: Given that coronary CTA is a new procedure that has aroused much interest and has been shown to have very favorable results, the drop in its utilization rate in 2008 was surprising. A review of the literature indicates that there are shortcomings to the clinical diagnosis of coronary artery disease (which often includes the use of MPI), that coronary CTA can be used to stratify risk, and that it can expedite the workup of patients with acute chest pain in emergency departments. The evidence from the literature review suggests that both invasive coronary angiography and MPI may be overutilized, whereas coronary CTA is probably underutilized.

A time and imaging cost analysis of low-risk ED observation patients: a conservative 64-section computed tomography coronary angiography "triple rule-out" compared to nuclear stress test strategy.

STUDY OBJECTIVE: The study aimed to examine time and imaging costs of 2 different imaging strategies for low-risk emergency department (ED) observation patients with acute chest pain or symptoms suggestive of acute coronary syndrome. We compared a "triple rule-out" (TRO) 64-section multidetector computed tomography protocol with nuclear stress testing. METHODS: This was a prospective observational cohort study of consecutive ED patients who were enrolled in our chest pain observation protocol during a 16-month period. Our standard observation protocol included a minimum of 2 sets of cardiac enzymes at least 6 hours apart followed by a nuclear stress test. Once a week, observation patients were offered a TRO (to evaluate for coronary artery disease, thoracic dissection, and pulmonary embolus) multidetector computed tomography with the option of further stress testing for those patients found to have evidence of coronary artery disease. RESULTS: We analyzed 832 consecutive observation patients including 214 patients who underwent the TRO protocol. Mean total length of stay was 16.1 hours for TRO patients, 16.3 hours for TRO plus other imaging test, 22.6 hours for nuclear stress testing, 23.3 hours for nuclear stress testing plus other imaging tests, and 23.7 hours for nuclear stress testing plus TRO (P < .0001 for TRO and TRO + other test compared to stress test ± other test). Mean imaging times were 3.6, 4.4, 5.9, 7.5, and 6.6 hours, respectively (P < .05 for TRO and TRO + other test compared to stress test ± other test). Mean imaging costs were $1307 for TRO patients vs $945 for nuclear stress testing. CONCLUSION: Triple rule-out reduced total length of stay and imaging time but incurred higher imaging costs. A per-hospital analysis would be needed to determine if patient time savings justify the higher imaging costs.

Cost-effectiveness of coronary CT angiography in evaluation of patients without symptoms who have positive stress test results.

OBJECTIVE: Patients without symptoms who have positive stress test results are often referred for diagnostic catheter angiography in an evaluation for coronary artery disease (CAD). The purpose of this study was to use decision tree analysis to determine the cost-effectiveness and radiation dose that would result from performing coronary CT angiography (CTA) before catheterization. MATERIALS AND METHODS: A decision tree was constructed to compare the false-negative rates, false-positive rates, costs, and radiation exposure of direct referral of patients for cardiac catheterization with the values associated with performing coronary CTA before catheterization. We assumed that patients referred for coronary CTA proceed to catheterization only when significant disease is identified. Costs for coronary CTA and diagnostic catheterization were obtained from the 2009 physician Medicare fee schedule. Sensitivity, specificity, and radiation dose were obtained by literature review. RESULTS: Cost reduction with coronary CTA depends on the prevalence of coronary artery disease, but overall costs are reduced as long as the prevalence is less than 85%. At a 50% prevalence of coronary artery disease, performing coronary CTA before cardiac catheterization results in an average cost saving of $789 per patient with a false-negative rate of 2.5% and average additional radiation exposure of 1-2 mSv. CONCLUSION: Performing coronary CTA before cardiac catheterization is a cost-effective strategy in the care of patients without symptoms who have positive stress test results when the probability that the patient has significant coronary artery disease is less than 50%. The false-negative rate with this strategy compares favorably with the false-negative rate of stress testing. The use of coronary CTA in this role can avoid many unnecessary cardiac catheterization procedures.

Decision analytic model for evaluation of suspected coronary disease with stress testing and coronary CT angiography.

RATIONALE AND OBJECTIVES: The aim of this study was to apply a decision analytic model for the evaluation of coronary artery disease (CAD) to define the optimal utilization of coronary computed tomographic angiography (cCTA) and stress testing. MATERIALS AND METHODS: The model tested in this study assumes that CAD is evaluated with a stress test and/or cCTA and that a patient with positive evaluation results undergoes cardiac catheterization. On the basis of values of sensitivity, specificity, and radiation dose from the published literature and test costs from the Medicare fee schedule, a decision tree model was constructed as a function of disease prevalence. RESULTS: The false-negative rate is lowest when cCTA is used as an isolated test. The false-positive rate is minimized when cCTA is used in combination with stress echocardiography. Effective radiation is minimized by use of stress electrocardiography or stress echocardiography alone or prior to cCTA. When the pretest probability of CAD is low, a strategy that uses stress echocardiography followed by cCTA minimizes the false-positive rate and effective radiation exposure, with relatively low imaging costs and with a false-negative rate only slightly higher than a strategy including stress myocardial scintigraphy. As the pretest probability of CAD increases above 20%, the false-negative rate of stress echocardiography followed by cCTA increases by >5% relative to cCTA alone. CONCLUSION: Effective radiation dose and imaging costs for the workup of CAD may be minimized by an appropriate combination of stress testing and cCTA. A strategy that uses stress echocardiography followed by cCTA is most appropriate for the evaluation of low-risk patients with CAD with a pretest probability < 20%, while cCTA alone may be more appropriate in intermediate-risk patients.

Is coronary stent assessment improved with spectral analysis of dual energy CT?

RATIONALE AND OBJECTIVES: The aims of this study were to distinguish stents from iodinated contrast on the basis of spectral characteristics on dual-energy computed tomographic (DECT) imaging and to determine whether DECT imaging might provide a more accurate measurement of true stent lumen. MATERIALS AND METHODS: Three stainless steel stents and one cobalt chromium stent were scanned using a multidetector, single-source DECT scanner. Stents 2.5, 3.5, and 4.0 mm in diameter were filled with iodinated contrast, submerged in water, and scanned. Spectral analysis was performed to assess the separation of stents from iodinated contrast. Two independent reviewers measured stent lumen diameter and strut thickness on low-energy (L(0)), high-energy (L(1)), and combined-energy (L(c)) images. Dual-energy full-width half-maximum edge detection analysis was used to provide an independent assessment of stent luminal diameter and strut thickness. RESULTS: Two-dimensional graphical plots of computed tomographic attenuation for the L(0) and L(1) images did not demonstrate a sharp separation between the absorption characteristics of stents and iodinated contrast material. Stent lumens were underestimated by approximately 50% on L(c) images. Observer measurements on L(1) images demonstrated a 24% decrease in strut thickness and a 25% increase in stent luminal diameter compared to L(0) images (P < .0001). Full-width half-maximum measurements did not demonstrate significant changes in stent luminal diameters or strut thicknesses between L(0) and L(1) images. CONCLUSIONS: Spectral analysis did not clearly distinguish stents from iodinated contrast with the DECT system used in this study. The larger stent lumens visualized by the high-energy components of the x-ray spectrum were not related to improved computed tomographic delineation of stent thickness.

Carpal tunnel syndrome assessment with US: value of additional cross-sectional area measurements of the median nerve in patients versus healthy volunteers.

PURPOSE: To improve accuracy in the diagnosis of carpal tunnel syndrome (CTS) by comparing cross-sectional area (CSA) measurements of the median nerve obtained at the level of the carpal tunnel (CSAc) with those obtained more proximally (CSAp), at the level of the pronator quadratus muscle. MATERIALS AND METHODS: The study protocol was approved by the institutional review board, and all subjects gave written informed consent. One hundred wrists of 68 consecutive patients with CTS (16 men, 52 women; mean age, 57.9 years; range, 25-85 years) and 93 wrists of 58 healthy volunteers (16 male, 42 female; mean age, 55.1 years; range, 17-85 years) were examined with ultrasonography (US). Electrodiagnostic test results confirmed the diagnosis of CTS in all 68 patients. The US examiner was blinded to these test results. The CSA of the median nerve was measured at the carpal tunnel and proximal levels, and the difference between CSAc and CSAp (Delta CSA) was calculated for each wrist. RESULTS: The mean CSAc in healthy volunteers (9.0 mm(2)) was smaller than that in patients (16.8 mm(2), P < .01). The mean Delta CSA was smaller in asymptomatic wrists (0.25 mm(2)) than in CTS-affected wrists (7.4 mm(2), P < .01). Receiver operating characteristic analysis revealed a diagnostic advantage to using the Delta CSA rather than the CSAc (P = .036). Use of a Delta CSA threshold of 2 mm(2) yielded the greatest sensitivity (99%) and specificity (100%) for the diagnosis of CTS. CONCLUSION: Receiver operating characteristic analysis revealed improved accuracy in the diagnosis of CTS determined with the Delta CSA compared with the accuracy of the diagnosis determined with the CSAc.

Science to practice: Noninvasive assessment of portal hypertension--can US aid in the prediction of portal pressure and monitoring of therapy?

A method that could be used to accurately assess portal venous pressure would be valuable when diagnosing portal hypertension, evaluating patient prognosis, and monitoring the progress of therapy. Baik et al have suggested that a qualitative noninvasive Doppler US parameter can be used to monitor therapy of portal hypertension. Further clinical investigation is needed to confirm these results and to determine whether hepatic venous Doppler waveform tracings can be used to monitor patient response to therapy. Ongoing research suggests that microbubble contrast agents may enable a more quantitative noninvasive estimate of intravascular pressures with US.

Angiographic assessment of initial balloon angioplasty results.

PURPOSE: To determine the influence of three factors involved in the angiographic assessment of balloon angioplasty-interobserver variability, operator bias, and the definition used to determine success-on the primary (technical) results of angioplasty in the peripheral arteries. MATERIALS AND METHODS: Percent stenosis in 107 lesions in lower-extremity arteries was graded by three independent, experienced vascular radiologists ("observers") before and after balloon angioplasty and their estimates were compared with the initial interpretations reported by the physician performing the procedure ("operator") and an automated quantitative computer analysis. Observer variability was measured with use of intraclass correlation coefficients and SD. Differences among the operator, observers, and the computer were analyzed with use of the Wilcoxon signed-rank test and analysis of variance. For each evaluator, the results in this series of lesions were interpreted with three different definitions of success. RESULTS: Estimation of residual stenosis varied by an average range of 22.76% with an average SD of 8.99. The intraclass correlation coefficients averaged 0.59 for residual stenosis after angioplasty for the three observers but decreased to 0.36 when the operator was included as the fourth evaluator. There was good to very good agreement among the three independent observers and the computer, but poor correlation with the operator (P