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ImportanceChest radiography (chest x-ray [CXR] and chest computed tomography [CT]) is the most common imaging in blunt trauma evaluation. Unnecessary trauma imaging leads to greater costs, emergency department time, and patient exposure to ionizing radiation. OBJECTIVE To validate our previously derived decision instrument (NEXUS Chest) for identification of blunt trauma patients with very low risk of thoracic injury seen on chest imaging (TICI). We hypothesized that NEXUS Chest would have high sensitivity (>98%) for the prediction of TICI and TICI with major clinical significance.Design, setting, and participantsFrom December 2009 to January 2012, we enrolled blunt trauma patients older than 14 years who received chest radiography in this prospective, observational, diagnostic decision instrument study at 9 US level I trauma centers. Prior to viewing radiographic results, physicians recorded the presence or absence of the NEXUS Chest 7 clinical criteria (age >60 years, rapid deceleration mechanism, chest pain, intoxication, abnormal alertness/mental status, distracting painful injury, and tenderness to chest wall palpation).Main outcomes and measuresThoracic injury seen on chest imaging was defined as pneumothorax, hemothorax, aortic or great vessel injury, 2 or more rib fractures, ruptured diaphragm, sternal fracture, and pulmonary contusion or laceration seen on radiographs. An expert panel generated an a priori classification of clinically major, minor, and insignificant TICIs according to associated management changes.ResultsOf 9905 enrolled patients, 43.1% had a single CXR, 42.0% had CXR and chest CT, 6.7% had CXR and abdominal CT (without chest CT), 5.5% had multiple CXRs without CT, and 2.6% had chest CT alone in the emergency department. The most common trauma mechanisms were motorized vehicle crash (43.9%), fall (27.5%), pedestrian struck by motorized vehicle (10.7%), bicycle crash (6.3%), and struck by blunt object, fists, or kicked (5.8%). Thoracic injury seen on chest imaging was seen in 1478 (14.9%) patients with 363 (24.6%) of these having major clinical significance, 1079 (73.0%) minor clinical significance, and 36 (2.4%) no clinical significance. NEXUS Chest had a sensitivity of 98.8% (95% CI, 98.1%-99.3%), a negative predictive value of 98.5% (95% CI, 97.6%.6-99.1%), and a specificity of 13.3% (95% CI, 12.6%-14.1%) for TICI. The sensitivity and negative predictive value for TICI with clinically major injury were 99.7% (95% CI, 98.2%-100.0%) and 99.9% (95% CI, 99.4%-100.0%), respectively.Conclusions and relevanceWe have validated the NEXUS Chest decision instrument, which may safely reduce the need for chest imaging in blunt trauma patients older than 14 years.

Objectives Scaphoid fractures are the most common carpal fracture, representing 70% of carpal bone fractures. The diagnostic accuracy of physical examination findings and emergency medicine (EM) imaging studies for scaphoid fracture has not been previously described in the EM literature. Plain x-rays are insufficient to rule out scaphoid fractures in a patient with a suggestive mechanism and radial-sided tenderness on physical examination. This study was a meta-analysis of historical features, physical examination findings, and imaging studies for scaphoid fractures not visualized on plain x-ray in adult emergency department (ED) patients, specifically to address which types of imaging tests should be recommended in patients with persistent concern for acute fracture after ED discharge. Methods A medical librarian and two emergency physicians (EPs) conducted a medical literature search of PUBMED and EMBASE. The original studies' bibliographies were reviewed for additional references and unpublished manuscripts were located via a hand search of EM research abstracts from national meetings. All abstracts were independently reviewed by the two physicians, and Quality Assessment Tool for Diagnostic Accuracy Studies (QUADAS-2) was used to assess individual study quality. When two or more qualitatively similar studies were identified, meta-analysis was conducted using Meta-DiSc software. Primary outcomes were sensitivity, specificity, and likelihood ratios (LRs) for predictors of scaphoid fracture detected on follow-up in patients with normal ED x-rays. Results A total of 957 unique citations were identified, yielding 75 studies eligible for inclusion in this systematic review. Studies were significantly heterogeneous in design, study population, and criterion standard. The majority of studies were conducted in non-ED settings (e.g., orthopedic clinics). No studies used accepted diagnostic research publishing guidelines, and the overall QUADAS-2 methodologic quality was low, indicating an increased risk of bias in the estimates of diagnostic accuracy. The prevalence of scaphoid fractures ranged from 12% to 57% with the point estimate of 25% pretest probability for adult ED patients with concern for scaphoid injuries, nondiagnostic index x-rays, and scaphoid fractures on later imaging studies. Except for the absence of snuffbox tenderness (LR– = 0.15), physical examination findings lack accuracy to rule in or rule out scaphoid fractures, and no validated clinical decision rules exist. In patients with persistent concern for injury, magnetic resonance imaging (MRI) is superior to bone scan, computed tomography (CT), or ultrasound (US) to both rule in and rule out scaphoid fractures. Both MRI and CT share the added benefit of identifying alternative etiologies for posttraumatic wrist pain. Conclusions Except for the absence of snuffbox tenderness, which can significantly reduce the probability of scaphoid fracture, history and physical examination alone are inadequate to rule in or rule out scaphoid fracture. MRI is the most accurate imaging test to diagnose scaphoid fractures in ED patients with no evidence of fracture on initial x-rays. If MRI is unavailable, CT is adequate to rule in scaphoid fractures, but inadequate for ruling out scaphoid fractures.

The levels of circulating immune complexes (CIC) were assayed in the sera of 109 patients with intracranial space occupying lesions. The CIC levels were significantly increased in all the brain tumours. After treatment, the CIC levels were still significantly increased when compared to the controls but showed no change when compared to their respective pre-operative values. Further, no change was observed in the CIC levels between the malignant and benign tumour case. Moreover, in brain tumours, 90% of the CIC precipitate consisted of IgG. However, the CIC levels fail to prognosticate the process of the disease in these patients.

Diagnosing subarachnoid hemorrhage (SAH) in emergency department (ED) patients is challenging. Potential diagnostic strategies include computed tomography (CT) only, CT followed by lumbar puncture (CT/LP), CT followed by magnetic resonance imaging and angiography (CT/MRA), and CT followed by CT angiography (CT/CTA). The objective was to determine the relative cost-effectiveness of diagnostic strategies for SAH. The authors created a decision model to evaluate the cost-effectiveness of SAH diagnostic strategies in ED patients with suspected SAH. Clinical probabilities were obtained from published data; sensitivity analyses were conducted across plausible ranges. In the base-case scenario, CT-only had a cost of $10,339 and effectiveness of 20.25 quality-adjusted life-years (QALYs), and CT/LP had a cost of $15,120 and effectiveness of 20.366 QALYs. Among the alternative strategies, CT/CTA had a cost of $12,840 and effectiveness of 20.24 QALYs, and CT/MRA had a cost of $16,207 and effectiveness of 20.27 QALYs. In sensitivity analyses, probability of severe disability from SAH, sensitivity of noncontrast CT, and specificity of LP and MRA were key drivers of the model, and CT-only and CT/LP were preferable.In the base-case scenario, CT-only was preferable to the CT/CTA and CT/MRA strategies. When considering sensitivity analyses and the current medicolegal environment, there are no overwhelming differences between the cost-effectiveness of CT/LP and the alternative strategies to suggest that clinicians should abandon the standard CT/LP approach.

Background Hemorrhage after trauma is a common cause of death in the United States and globally. The primary goals when managing traumatic shock are the restoration of oxygen delivery to end organs, maintenance of circulatory volume, and prevention of ongoing bleeding through source control and correction of coagulopathy. Achieving these goals may require massive transfusion of blood products. Although use of blood products may be lifesaving, dose-related adverse effects are well described. Discussion Complications of massive transfusion include interdependent derangements such as coagulopathy, hypothermia, acidosis, and electrolyte abnormalities, as well as infectious and immunomodulatory phenomena. This article explores the pathogenesis, implications, prevention, and treatment of these complications through the use of massive transfusion protocols. Particular attention is given to the optimal ratio of blood products transfused in large volume resuscitation and prevention of secondary coagulopathy. Conclusions Observational data indicate that the development and use of a massive transfusion protocol may reduce the morbidity and mortality associated with large-volume resuscitation of patients with hemorrhagic shock. Such protocols should include a pre-defined ratio of packed red blood cells, fresh frozen plasma, and platelets transfused; most commonly, the ratio used is 1:1:1. Additionally, such protocols should monitor for and correct hypothermia, hypofibrinogenemia, and electrolyte disturbances such as hypocalcemia and hyperkalemia.

Objective Variation in emergency department head computed tomography (CT) use in patients with atraumatic headaches between hospitals is being measured nationwide. However, the magnitude of interphysician variation within a hospital is currently unknown. We hypothesized that there was significant variation in the rates of physician head CT use, both overall and for patients diagnosed with atraumatic headaches. Methods This cross-sectional study was conducted in the emergency department of a large urban academic hospital, and institutional review board approval was obtained. All emergency department visits from 2009 were analyzed, and the primary outcome measure was whether or not head CT was performed. Logistic regression was used to control for patient, physician, and visit characteristics potentially associated with head CT ordering. The degree of interphysician variability was tested, both before and after controlling for these variables. Results Of 55,286 emergency department patient encounters, 4919 (8.9%) involved head CT examinations. Unadjusted head CT ordering rates per physician ranged from 4.4% to 16.9% overall and from 15.2% to 61.7% in patients diagnosed with atraumatic headaches, with both rates varying significantly between physicians. Two-fold variation in head CT ordering overall (6.5%-13.5%) and approximately 3-fold variation in head CT ordering for atraumatic headaches (21.2%-60.1%) persisted even after controlling for pertinent variables. Conclusion Emergency physicians vary significantly in their use of head CT both overall and in patients with atraumatic headaches. Further studies are needed to identify strategies to reduce interphysician variation in head CT use.

Computed tomography angiograms (CTAs) for patients with suspected pulmonary embolism (PE) are being ordered with increasing frequency from the emergency department (ED). Strategies are needed to safely decrease the utilization of CTs to control rising health care costs and minimize the associated risks of anaphylaxis, contrast-induced nephropathy, and radiation-induced carcinogenesis. The use of compression ultrasonography (US) to identify deep vein thromboses (DVTs) in hemodynamically stable patients with signs and symptoms suggestive of PE is highly specific for the diagnosis of PE and may represent a cost-effective alternative to CT imaging. The objective was to analyze the cost-effectiveness of a selective CT strategy incorporating the use of compression US to diagnose and treat DVT in patients with a high pretest probability of PE.The authors constructed a decision analytic model to evaluate the scenario of an otherwise healthy 59-year-old female in whom PE was being considered as a diagnosis. Two strategies were used. The selective CT strategy began with a screening compression US. Negative studies were followed up with a CTA, while patients with positive studies identifying a DVT were treated as though they had a PE and were anticoagulated. The universal CT strategy used CTA as the initial test, and anticoagulation was based on the CT result. Costs were estimated from the 2009 Medicare data for hospital reimbursement, and professional fees were obtained from the 2009 National Physician Fee Schedule. Clinical probabilities were obtained from existing published data, and sensitivity analyses were performed across plausible ranges for all clinical variables.In the base case, the selective CT strategy cost $1,457.70 less than the universal CT strategy and resulted in a gain of 0.0213 quality-adjusted life-years (QALYs). Sensitivity analyses confirm that the selective CT strategy is dominant above both a pretest probability for PE of 8.3% and a compression US specificity of 87.4%.A selective CT strategy using compression US is cost-effective for patients provided they have a high pretest probability of PE. This may reduce the need for, and decrease the adverse events associated with, CTAs.

The majority of chest pain admissions originate in the emergency department (ED). Despite a low incidence of cardiac events, limited telemetry availability, and its questionable benefit, these patients are routinely admitted to a monitored setting.The objectives were to analyze the cost-effectiveness of admission to telemetry versus admission to an unmonitored hospital bed in low-risk chest pain patients and explore when the use of telemetry may be cost-effective.The authors constructed a decision analytic model to evaluate the scenario of an ED admission of an otherwise healthy 55-year-old patient with low-risk chest pain defined as an acute coronary syndrome (ACS) probability of 2%. Costs were estimated from 2009 Medicare data for hospital reimbursement and physician services, as well as published data on disability costs. Published studies were used to estimate the risk of ACS, cardiac arrest, time to defibrillation, survival, long-term disability, and quality of life.In the base case, telemetry was more effective (0.0044 quality-adjusted life-years [QALYs]) but more costly ($299.67) than a floor bed, resulting in a high marginal cost-effectiveness ratio (mCER) of $67,484.55 per QALY. In comprehensive sensitivity analyses, the mCER crossed below the willingness-to-pay (WTP) threshold of $50,000 per QALY when the following scenarios were met: the probability of ACS exceeds 3%, the probability of cardiac arrest is greater than 0.4%, the probability of shockable dysrhythmia is above 83%, the probability of delay in telemetry bed availability is below 52%, and the opportunity cost of delay to telemetry bed placement is below $119.Telemetry may be a "cost-effective" use of health care resources for chest pain patients when patients have a probability of ACS above 3% or for patients with a minimal delay and cost associated with obtaining a monitored bed. Further research is needed to better stratify low-risk chest pain patients to the appropriate inpatient setting and to understand the frequency and costs associated with delays in obtaining monitored beds.

Previous research suggests that video laryngoscopy may be superior to direct laryngoscopy.We sought to determine the proportion of Massachusetts emergency departments (EDs) that have adopted video laryngoscopy, the characteristics of user and non-user EDs, the reasons why non-users do not use video laryngoscopy, and how the adoption of video laryngoscopy compares to typical technology adoption life cycles.Surveys were mailed to directors of all non-federal EDs in Massachusetts (n=74) in early 2009. Non-responders received repeat mailings and were then contacted via telephone or e-mail.Sixty-three of 74 (85%) EDs responded and 43% had adopted video laryngoscopy. EDs with video laryngoscopy had a higher median annual visit volume than EDs without video laryngoscopy (48,000 vs. 36,500, p=0.04), but had similar mean intubations per week (4.5 vs. 4.4, p=0.97) and mean surgical airways per year (0.7 vs. 1.1, p=0.19). Half of the EDs affiliated with emergency medicine residency programs had video laryngoscopy available. Among EDs with video laryngoscopy, the technology had been available for5 years in 4% (1/27), 1-5 years in 44% (12/27), and1 year in 52% (14/27). Although EDs not using video laryngoscopy did not do so primarily because it was too expensive (69% [25/36]), video laryngoscopy adoption has still progressed more rapidly than predicted by the typical technology adoption timeline.Video laryngoscopy has been adopted by 43% of Massachusetts EDs; results were similar in academic institutions. Cost is the primary barrier to adoption for non-user EDs, but adoption is progressing more rapidly than expected for a new technology.

Objectives: Financial conflicts of interest have come under increasing scrutiny in medicine, but their impact has not been quantified. Our objective was to use the results of a national survey of academic emergency medicine (EM) faculty to determine if an association between money and personal opinion exists. Methods: We conducted a web-based survey of EM faculty. Opinion questions were analyzed with regard to whether the respondent had either 1) received research grant money or 2) received money from industry as a speaker, consultant, or advisor. Responses were unweighted, and tests of differences in proportions were made using Chi-squared tests, with p

Objectives: The authors surveyed the membership of the Society for Academic Emergency Medicine (SAEM) about their associations with industry and predictors of those associations. Methods: A national Web-based survey inviting faculty from the active member list of SAEM was conducted. Follow-up requests for participation were sent weekly for 3 weeks. Information was collected on respondents’ personal and practice characteristics, industry interactions, and personal opinions regarding these interactions. Raw response rates were reported and a logistic regression was used to generate descriptive statistics. Results: Responses were received from 430 members, representing 14% of the 3,183 active members. Respondents were 83% male and 86% white, with 96% holding an MD degree (24% with an additional postdoctoral degree). Most were at the assistant (37%) or associate (25%) professor rank, with 51% holding at least one leadership position. Most respondents (82%) reported some type of industry interaction, most commonly the acceptance of food or beverages (67%). Respondents at the associate professor rank or higher were more likely to receive payments from industry (51% vs. 22%, odds ratio [OR] = 3.7). Conclusions: This survey suggests that interactions between industry and academic EM faculty are common and increase with academic rank, but not with years in practice or leadership influence. The number and type of interactions are consistent with those reported by a national sampling of other physician specialties. ACADEMIC EMERGENCY MEDICINE 2008; 15:819–824 a 2008 by the Society for Academic Emergency

Study objective Patient-reported penicillin allergies are often unreliable and can result in unnecessary changes in antibiotic therapy. Although penicillin allergy skin testing is commonly performed in allergy clinics, it has not been used in emergency departments (EDs) to verify self-reported allergies. We hypothesize that ED-based testing is possible and that the false-positive rate of patients with self-reported penicillin allergy are greater than 90%. Methods This prospective observational cohort study enrolled a convenience sample of ED patients with a self-reported penicillin allergy. Patients were enrolled by one of 2 emergency physicians who performed skin prick and intracutaneous tests with penicillin major and minor determinants. The total testing time was 30 minutes. The proportion of false-positive self-reported allergies was computed with 95% confidence intervals (CIs) by using the score method. Results A total of 150 patients (mean age 42 years; SD 16 years; 46% men; 47% black) were enrolled. The false-positive rate for self-reported penicillin allergy was 137 of 150 (91.3%; 95% CI 85.3% to 95.1%). There were no adverse reactions associated with penicillin skin testing. Compared with patients with a false-positive penicillin allergy result (confirmed by negative penicillin skin testing result), patients reporting a true penicillin allergy confirmed by positive penicillin skin test results tended to be more frequently men (61.5% versus 44.5%; Δ 17.0%; 95% CI −13.5% to 42%), black (69.2% versus 44.5%; Δ 24.7%; 95% CI −6.9% to 46.8%), and have no family history of drug allergy (7.7% versus 17.5%; Δ9.8%; 95% CI −20.9% to 20.4%), but self-reported other drug allergies more frequently (61.5% versus 38.7%; Δ 22.9%; 95% CI −7.7% to 47.5%). Conclusion Penicillin skin testing is feasible in the ED setting. A substantial number of patients who self-report a penicillin allergy do not exhibit immunoglobulin E-mediated sensitization to penicillin major and minor determinants. Penicillin testing in the ED may allow the use of more appropriate antibiotics for patients presenting with a history of penicillin allergy.

Background Sleepiness is a significant problem among residents due to chronic sleep deprivation. Recent studies have highlighted medical errors due to resident sleep deprivation. We hypothesized residents routinely use pharmacologic sleep aids to manage their sleep deprivation and reduce sleepiness. Methods A web-based survey of US allopathic Emergency Medicine (EM) residents was conducted during September 2004. All EM residency program directors were asked to invite their residents to participate. E-mail with reminders was used to solicit participation. Direct questions about use of alcohol and medications to facilitate sleep, and questions requesting details of sleep aids were included. Results Of 3,971 EM residents, 602 (16%) replied to the survey. Respondents were 71% male, 78% white, and mean (SD) age was 30 (4) years, which is similar to the entire EM resident population reported by the ACGME. There were 32% 1st year, 32% 2nd year, 28% 3rd year, and 8% 4th year residents. The Epworth Sleepiness Scale (ESS) showed 38% of residents were excessively sleepy (ESS 11–16) and 7% were severely sleepy (ESS>16). 46% (95 CI 42%–50%) regularly used alcohol, antihistamines, sleep adjuncts, benzodiazepines, or muscle relaxants to help them fall or stay asleep. Study limitations include low response and self-report. Conclusion Even with a low response rate, sleep aid use among EM residents may be common. How this affects performance, well-being, and health remains unknown.

We present a case of papillary cystic low-grade adenocarcinoma of endolymphatic sac origin. These tumors are very rare and only a few cases have been reported in literature. They have a protracted clinical course causing progressive invasion and bony destruction. Radiologically, they appear as a heterogenous lobulated vascular mass, invading bone and compressing surrounding structures. Histologically, these tumors are composed of uniform population of cells, resembling normal endolymphatic sac epithelium. This causes considerable diagnostic difficulty. A strong index of suspicion along with clinical and radiological correlation is essential to arrive at a correct diagnosis. In some bilateral cases, association with von Hippel–Lindau disease has been noted. Radical mastoidectomy and temporal bone resection, which may sometimes necessitate sacrifice of cranial nerves, is the treatment of choice.

The dura provides an excellent protection against infiltration by malignant tumours. It is extremely rare for glial tumour cells to infiltrate the dura and subsequently invade adjacent structures. We report an interesting case of glioblastoma of the temporal lobe with spontaneous transdural spread to the skull base and infratemporal fossa. This is the first radiologically documented case of transdural spread of glioblastoma before and after the spread without previous craniotomy.

Radiation therapy has played an important integral part in the management of various intracranial rumours. However, radiation has been implicated in the development of intracranial tumours. We describe three cases of radiation-induced meningiomas following high dose cranial irradiation. All these patients developed tumours within the previous radiation field and satisfied the criteria used for the definition of radiation-induced neoplasm. The interval between the irradiation and the onset of meningioma was significantly less in the younger patient. All the cases had several unique features of radiation-induced meningioma including features of atypical meningioma. Two patients developed multiple site meningiomas and one patient developed early recurrence of the tumour. This report confirms that patients exposed to cranial irradiation are at lifelong risk of developing radiation-induced tumours such as meningiomas. Hence these patients require long-term clinical and radiological surveillance to detect occurrence as early as possible.

The purpose of this study was to examine the impact of a multifaceted, clinical decision support (CDS)-enabled intervention on magnetic resonance imaging (MRI) use in adult primary care patients with low back pain.After a baseline observation period, we implemented a CDS targeting lumbar-spine MRI use in primary care patients with low back pain through our computerized physician order entry, as well as 2 accountability tools: mandatory peer-to-peer consultation when test utility was uncertain and quarterly practice pattern variation reports to providers. Our primary outcome measure was rate of lumbar-spine MRI use. Secondary measures included utilization of MRI of any body part, comparing it with that of a concurrent national comparison, as well as proportion of lumbar-spine MRI performed in the study cohort that was adherent to evidence-based guideline. Chi-squared, t-tests, and logistic regression were used to assess pre- and postintervention differences.In the study cohort preintervention, 5.3% of low back pain-related primary care visits resulted in lumbar-spine MRI, compared with 3.7% of visits postintervention (P.0001, adjusted odds ratio 0.68). There was a 30.8% relative decrease (6.5% vs 4.5%, P.0001, adjusted odds ratio 0.67) in the use of MRI of any body part by the primary care providers in the study cohort. This difference was not detected in the control cohort (5.6% vs 5.3%, P = .712). In the study cohort, adherence to evidence-based guideline in the use of lumbar-spine MRI increased from 78% to 96% (P = .0002).CDS and associated accountability tools may reduce potentially inappropriate imaging in patients with low back pain.

Recent genetic studies have linked mental illness to alterations in disrupted in schizophrenia 1 (DISC1), a multifunctional scaffolding protein that regulates cyclic adenosine monophosphate (cAMP) signaling via interactions with phosphodiesterase 4 (PDE4). High levels of cAMP during stress exposure impair function of the prefrontal cortex (PFC), a region gravely afflicted in mental illness. As stress can aggravate mental illness, genetic insults to DISC1 may worsen symptoms by increasing cAMP levels. The current study examined whether viral knockdown (KD) of the Disc1 gene in rat PFC increases susceptibility to stress-induced PFC dysfunction. Rats were trained in a spatial working memory task before receiving infusions of (a) an active viral construct that knocked down Disc1 in PFC (DISC1 KD group), (b) a ‘scrambled' construct that had no effect on Disc1 (Scrambled group), or (c) an active construct that reduced DISC1 expression dorsal to PFC (Anatomical Control group). Data were compared with an unoperated Control group. Cognitive performance was assessed following mild restraint stress that had no effect on normal animals. DISC1 KD rats were impaired by 1 h restraint stress, whereas Scrambled, Control, and Anatomical Control groups were unaffected. Thus, knocking down Disc1 in PFC reduced the threshold for stress-induced cognitive dysfunction, possibly through disinhibited cAMP signaling at neuronal network synapses. These findings may explain why patients with DISC1 mutations may be especially vulnerable to the effects of stress.

Study objective Computed tomography (CT) use has increased rapidly, raising concerns about radiation exposure and cost. The Centers for Medicare & Medicaid Services (CMS) developed an imaging efficiency measure (Outpatient Measure 15 [OP-15]) to evaluate the use of brain CT in the emergency department (ED) for atraumatic headache. We aim to determine the reliability, validity, and accuracy of OP-15. Methods This was a retrospective record review at 21 US EDs. We identified 769 patient visits that CMS labeled as including an inappropriate brain CT to identify clinical indications for CT and reviewed the 748 visits with available records. The primary outcome was the reliability of OP-15 as determined by CMS from administrative data compared with medical record review. Secondary outcomes were the measure's validity and accuracy. Outcome measures were defined according to the testing protocol of the American Medical Association's Physician Consortium for Performance Improvement. Results On record review, 489 of 748 ED brain CTs identified as inappropriate by CMS had a measure exclusion documented that was not identified by administrative data; the measure was 34.6% reliable (95% confidence interval [CI] 31.2% to 38.0%). Among the 259 patient visits without measure exclusions documented in the record, the measure's validity was 47.5% (95% CI 41.4% to 53.6%), according to a consensus list of indications for brain CT. Overall, 623 of the 748 ED visits had either a measure exclusion or a consensus indication for CT; the measure's accuracy was 16.7% (95% CI 14% to 19.4%). Hospital performance as reported by CMS did not correlate with the proportion of CTs with a documented clinical indication ( r =–0.11; P =.63). Conclusion The CMS imaging efficiency measure for brain CTs (OP-15) is not reliable, valid, or accurate and may produce misleading information about hospital ED performance.