Emergency department time for evaluation of patients discharged with a diagnosis of renal colic: unenhanced helical computed tomography versus intravenous urography

The objective of this study was to determine whether patients discharged from the Emergency Department (ED) with a proven diagnosis of renal colic require less total evaluation and treatment time if unenhanced helical computed tomography (CT) rather than intravenous urography (IVU) was the diagnostic imaging study used. A retrospective review was undertaken of the medical records of 98 consecutive patients with a final diagnosis of urolithiasis or renal colic evaluated with an unenhanced helical CT scan or an IVU between January 1, 1999, and December 31, 1999. All patients were managed by Emergency Physicians and discharged from the ED. The time the patient was brought to the treatment area, the time the imaging study was ordered, and the time the patient was discharged were recorded. There were 75 patients evaluated with CT scan and 23 patients with an IVU. Patients who underwent unenhanced helical CT scan were in the ED for a mean time of 291 min [95% confidence interval (CI) 266–316] and those who had an IVU were in the ED for an average of 410 min (95% CI 340–481). Use of unenhanced helical CT scan was associated with less total time in the ED compared to IVU for patients with renal colic by a significant mean of 119 min. It is concluded that ED evaluation and treatment time of patients ultimately discharged with a proven diagnosis of renal colic is significantly less when evaluated with unenhanced helical CT scan compared to IVU.     

Value of computed tomography in the evaluation of retroperitoneal organ injury in blunt abdominal trauma

Computed tomography (CT) is widely used in the evaluation of blunt abdominal trauma. One of its purported advantages is in the evaluation of the retroperitoneum. This study was undertaken to determine the utility of CT in diagnosing retroperitoneal organ injury. A retrospective chart review of 466 stable patients with blunt abdominal trauma who received abdominal CT was conducted. Twelve percent of the patients had CT scans showing retroperitoneal organ injury. There were 58 total injuries, with the kidney being the most frequently injured organ. Twenty-four patients required laparotomy, confirming the CT diagnosis in 8 patients (7 renal and 1 pancreatic). Two duodenal injuries were found at laparotomy that had not been seen on CT scan. Fourteen percent of the patients with positive CT scans had a positive laparotomy, and of those, 38% were therapeutic. Five percent of the patients with positive scans had therapeutic laparotomies. These data infer that the utility of CT to define retroperitoneal organ injury is lower than previously suspected.     

Does computed tomographic scan affect diagnosis and management of patients with suspected renal colic?

Background

Patients with renal colic commonly present to the emergency department (ED) and are usually treated with analgesics, antiemetics and hydration. Computed tomographic (CT) scan is commonly utilized in evaluating patients with suspected renal colic.

Objectives

We compared diagnosis and treatment plans before and after CT in patients with suspected renal colic with the aim to evaluate how often changes in diagnosis, treatment and disposition are made.

Methods

In this prospective observational study, we enrolled a convenience sample of clinically Stable ED patients older than 17 with suspected renal colic for whom CT was planned. Exclusion criteria were: chronic kidney disease, urinary tract infection, recent CT and history of previous kidney stone. Pre-CT and Post-CT surveys were completed by the treating provider.

Results

The discharge diagnosis was renal colic in 62 of 93 enrolled patients (67%). Urinalysis showed blood in 52 of these patients (84%). CT confirmed obstructing kidney or bladder stone in 50 patients. There were five cases of alternative diagnoses noted on CT scan. After CT scan, 7 patients had changes in disposition. Sixteen providers felt that CT would not change management. In these cases, CT offered no alternative diagnosis and didn't change disposition.

Conclusion

CT scan didn't change management when providers did not expect it would. This indicates that providers who are confident with the diagnosis of renal colic should consider forgoing a CT scan. CT scan did occasionally find important alternative diagnoses and should be utilized when providers are considering other concerning pathology.     

The efficacy of urinalysis,plain films,and spiral CT in ED patients with suspected renal colic

We determined the diagnostic value of urinalysis and plain films in patients with suspected renal colic presenting to an emergency department (ED). Over a 1-year period, 138 patients presented to the ED during the daytime with suspected renal colic, but for technical reasons the diagnostic modalities used in the study could be completed for only 99 patients, and 34 patients were lost to follow-up. A urinalysis; kidney, ureter, and bladder film; and spiral computed tomography (CT) were performed on each patient. The presence of urinary tract stones was determined by their definite presence on helical CT and/or passage of a stone on clinical follow-up (average follow-up = 3 months). A urinary stone was visualized on spiral CT or passed in the urine in 54 of the patients. Using helical CT findings or passage of a stone as the gold standard, plain radiography had a sensitivity of 69% and specificity of 82%. Urinalysis had a sensitivity of 69% and specificity of 27%. The sensitivity increased to 89% if either test was positive, but the specificity remained low at 27%. The sensitivity and specificity of CT in the diagnosis of urinary stones was 91%. Urinalysis and plain films are much less accurate than helical CT for confirming the diagnosis of acute urolithiasis. Further evaluation of the clinical and cost-effectiveness of helical CT should be done to determine its role in the work-up of these patients.     

Does diagnosis change as a result of repeat renal colic computed tomography scan in patients with a history of kidney stones?

Study objective

We sought to determine the incidence of alternative diagnosis in patients with a history of kidney stones who experience recurrent symptoms and undergo repeat computed tomography (CT) imaging at their return to the emergency department (ED).

Methods

This was a retrospective chart review of ED patients at a tertiary care hospital. Inclusion criteria were all adult ED patients who received a repeat CT for renal colic, after having previously received the diagnosis of obstructive kidney stone confirmed by CT, in our ED. Patients were identified by reviewing the charts of those patients with repeat visits to the ED after January 1, 2004, in which they complained of symptoms suggestive of renal colic and received a CT scan. We determined the frequency of the same diagnosis on repeat CT scan in this population compared with the frequency of alternative diagnosis.

Results

Two hundred thirty-one patients met criteria for the study. Fifty-nine percent were male. One hundred eighty-nine (81.8%) patients had no change in diagnosis as a result of a repeat renal colic CT scan. Twenty-seven (11.6%) patients received an alternative diagnosis that did not require urgent intervention, and 15 (6.5%) patients received a diagnosis that did require an urgent intervention.

Conclusion

Repeat CT imaging of patients with known nephrolithiasis changed management in a minority of patients (6.5%). Knowing the frequency of alternative diagnosis in this population may help clinicians and patients balance the risks and benefits of repeat renal colic CT scans in patients with a history of kidney stones who return to the ED with similar symptoms.     

Racial disparities in analgesic use amongst patients presenting to the emergency department for kidney stones in the United States

IntroductionWe sought quantify racial disparities in use of analgesia amongst patients seen in Emergency Departments for renal colic.MethodsWe identified all individuals presenting to the Emergency Department with urolithiasis from 2003 to 2015 in the nationally representative Premier Hospital Database. We included patients discharged in ≤1 day and excluded those with chronic pain or renal insufficiency. We assessed the relationship between race/ethnicity and opioid dosage in morphine milligram equivalents (MME), and ketorolac, through multivariable regression models adjusting for patient and hospital characteristics.ResultsThe cohort was 266,210 patients, comprised of White (84%), Black (6%) and Hispanic (10%) individuals. Median opioid dosage was 20 MME and 55.5% received ketorolac. Our adjusted model showed Whites had highest median MME (20 mg) with Blacks (−3.3 mg [95% CI: −4.6 mg to −2.1 mg]) and Hispanics (−6.0 mg [95% CI: −6.9 mg to −5.1 mg]) receiving less. Blacks were less likely to receive ketorolac (OR: 0.72, 95% CI: 0.62–0.84) while there was no difference between Whites and Hispanics.ConclusionsBlack and Hispanic patients in American Emergency Departments with acute renal colic receive less opioid medication than White patients; Black patients are also less likely to receive ketorolac.     

Can noncontrast helical computed tomography replace intravenous urography for evaluation of patients with acute urinary tract colic?

The objective of this study was to determine whether helical computed tomography (CT) performed without oral or intravenous contrast agents is accurate in the evaluation of patients with suspected acute renal colic. One hundred consecutive patients with suspected renal colic or ureteral colic were referred by our institution's emergency department for unenhanced helical CT scans. We reviewed the original radiographic report for each patient and recorded the size and location of ureteral calculi and other concurrent urinary tract calculi, if any. We also recorded the presence or absence of hydronephrosis, hydroureter, perinephric edema, and periureteral edema. A total of 49 patients had ureteral calculi, 17 patients had only renal calculi, and 34 patients had no stones. Forty-nine patients had ureteral calculi, and 40 (82%) of these 49 patients had associated CT signs including hydroureter and periureteral edema. Calculi were present in the proximal ureter in 11 patients, the midureter in seven patients, and the distal ureter including ureterovesical junction in 31 patients. Calculi were seen elsewhere in the urinary tract and renal pelvis in 44 patients. Other diagnostic tests and stone passage were used to confirm the CT diagnosis of ureteral stones. The sensitivity and specificity of helical CT in evaluating ureteral calculi were 100% and 94%, respectively. Sixteen extraurinary lesions were detected in 34 patients who had no urinary calculi. Most extraurinary lesions (81%) were deemed the cause of acute flank pain. The room time for CT averaged 26 min, compared to 69 min for intravenous urography (IVU). The charge for CT was $600 compared to $400 for IVU in our institution. Unenhanced helical CT was fast and accurate in determining the cause of colic and proved to be highly accurate for emergency situations.     

Frequency and follow-up of incidental findings on trauma computed tomography scans: experience at a level one trauma center

Objectives: Incidental findings found on computed tomography (CT) scan during the Emergency Department evaluation of trauma patients are often benign, but their presence must always be communicated to patients, who should be referred for follow-up care. Our objective was to quantify the frequency of these incidental CT findings in trauma patients. A secondary goal was to determine how often these lesions were communicated to patients and how often patients were referred for follow-up. Methods: We performed a retrospective chart review of 500 consecutive patients presenting as trauma activations. Subjects received head, chest, or abdomen/pelvis CT scans at our hospital. Patients were identified using our trauma registry. Final CT reports were examined and discharge summaries were reviewed for basic demographics. Scans with incidental findings prompted detailed secondary review of discharge summaries to determine follow-up. Investigators reviewed incidental findings and classified them into three groups by clinical importance, using predetermined criteria. Results: Of the 500 patient charts identified for review, 480 (96%) were available, yielding 1930 CT reports for analysis. Incidental findings were noted in 211 of 480 (43%) patients and on 285 (15%) of the 1930 CT studies performed for the 480 patients. Of available patient records, only 27% of patient charts had mention of the finding in the discharge summary, had documentation of an in-hospital workup, or had documentation of a referral for follow-up. Most-concerning lesions, such as suspected malignancies or aortic aneurysms, accounted for 15% of all incidental findings and were referred for follow-up in only 49% of cases. Conclusions: Incidental findings were noted in 15% of trauma CT scans. Follow-up was poor, even for potentially serious findings. Further studies should examine the long-term outcome of patients with these findings.     

Headache in the emergency department

Non-traumatic headache is an unusual presenting complaint in emergency medicine, representing only 1.4% of all patients seen over 45 consecutive days at the Royal Hobart Hospital Department of Emergency Medicine. Computerised tomographic (CT) scanning was used to assist diagnosis in 28% of cases, with nearly half (47%) of CT scans positive. Twenty three percent of patients were admitted to hospital. Emergency physicians are reminded that patients with headache commonly have serious underlying pathology.     

Computed tomography scan versus ventilation-perfusion lung scan in the detection of pulmonary embolism

This study compared the sensitivity and specificity of computed tomography (CT) scan and ventilation-perfusion (V-P) scan in detecting pulmonary embolism (PE) with pulmonary angiogram (AG) as the reference standard. Following a comprehensive search of the indexed medical literature, CT scan studies related to PE diagnosis were systematically evaluated to select those using AG as the reference standard and meeting specified methodologic criteria. Studies were further grouped by those reporting results for central PE findings only versus central and peripheral PE combined. A composite analysis of data derived from seven selected publications yielded sensitivity and specificity estimates for CT scan in detecting PE, which were statistically compared to the published results of a multi-center study reporting the sensitivity and specificity of the V-P scan with pulmonary AG as the reference standard. The calculated CT scan sensitivity was 77% for central PE only data and 81% for central and peripheral PE combined data, and the CT scan specificity was 91% and 98%, respectively. High-probability V-P scan sensitivity was 41% and specificity 97%; high- and intermediate-probability V-P scans combined yielded sensitivity 83% and specificity 52%. The sensitivity for PE detection was significantly greater for CT scan than for high-probability V-P scan; CT scan sensitivity was equivalent to V-P when high- and intermediate-probability scans were considered together. CT scan specificity for central and peripheral PE combined was equivalent to that of the high-probability V-P scan, but significantly greater than that of high- and intermediate-probability V-P scans considered together. Considering that only a small proportion of patients with suspected PE yield high-probability V-P scan results (which are usually indicative of PE), while as many as one-half of patients may yield intermediate-probability results (which are commonly not useful in PE diagnosis), our results suggest the CT scan may be an appropriate study for use by Emergency Physicians in the clinical evaluation of suspected PE.     

16-MDCT低剂量平扫在肾绞痛病因诊断中的应用

目的回顾性分析16-MDCT低剂量扫描在肾绞痛检查病因诊断中的应用价值。方法106例因“肾绞痛”要求低剂量CT筛查的患者纳入分析研究,男68例,女38例,平均年龄44岁,采用16-MDCT机,层厚1mm,120kV,60～150mA,0．5s／rot,并辅以全程输尿管曲面重建进行评价。结果除1例输尿管下端小结石外,MDCT正确诊断尿路结石共52例（肾结石23例侧,输尿管结石41例侧、膀胱结石1例）,显示尿路积水22例侧、尿外渗7例侧。MDCT影像诊断尿路结石的敏感性98．1％,特异性100％,准确性99．1％;其中肾结石诊断准确性达到100％。低剂量CT同时显示肾囊肿18例,疑诊肿瘤1例,输尿管先天异常4例,未见漏诊。结论MDCT薄层低剂量扫描检出尿路结石具有极高的敏感性、特异性和准确性,并可以有效提示其他病变。     

Clinical decision instruments for CT scan in minor head trauma

Previous studies have presented conflicting results regarding the predictive value of various clinical symptoms and signs for performing computed tomography (CT) scan in minor head injury. Moreover, despite the presence in the literature of several similar publications regarding whether or not CT should be employed at the time of presentation of minor head injured patients, data regarding delayed CT are limited. The objective of this study was to determine whether high-risk criteria represent a significant indication for initial CT scan in patients with minor head trauma, and whether or not analysis using delayed CT scan is necessary in patients with high-risk criteria before being discharged. Patients presenting to the Emergency Department with minor head trauma between September 1, 2003 and September 1, 2004 were evaluated prospectively. After being divided into two main groups, low- and high-risk, four separate sub-groups based on age were established. Initial spiral CT examination was done within 3 h of trauma on all patients in addition to a delayed control CT scan in those with high-risk criteria between 16 and 24 h after trauma. The difference between the high- and low-risk groups in terms of abnormal CT findings was statistically significant (p < 0.0005). Among high-risk patients there was a significant difference between patients with a Glasgow Coma Scale (GCS) score of 13 or 14 and those with a GCS score of 15 (p < 0.0005). The relationship between vomiting and abnormal CT scan was significant (odds ratio 4.61, 95% confidence interval 2.20-9.64, p = 0.0001), and the relationship between abnormal CT scan and suspected skull fracture was also significant (odds ratio 3.46, 95% confidence interval 1.52-7.91, p = 0.0032). No significant correlations between other high-risk criteria and abnormal CT scan were determined. The difference between initial and delayed CT scans in patients with high-risk criteria was not significant (p = 0.161). Low-risk patients with a GCS score of 15 may be discharged without initial CT scan being performed. Initial CT scan absolutely must be performed, however, on patients with GCS < or = 15 in the event of vomiting or suspected skull fracture, even if isolated. Even though the difference between initial and delayed CT scans in patients with high-risk criteria is not significant, it is our opinion that it is still prudent for delayed CT scan to be performed, particularly on patients whose GCS score does not rise to 15, or decreases.     

Impact of CT scan in patients with first episode of suspected nephrolithiasis

This prospective observational outcome study assessed the impact of helical computed tomography (CT) scan in patients with a first episode of suspected nephrolithiasis. Before CT scanning, Emergency Physicians completed a questionnaire, including diagnostic certainty of nephrolithiasis and anticipated patient disposition. Primary outcome measure was the comparison of physician diagnostic certainty and CT scan results. Secondary outcome measures included alternate diagnoses and changes in patient disposition after CT scan. Four categories grouped the pre-CT diagnostic certainty: 0-49%, 50-74%, 75-90%, and 90-100%. The CT scan found urinary calculi in 28.6%, 45.7%, 74.2%, and 80.5% of patients in each category, respectively. CT scanning revealed alternate diagnoses in 40 cases (33.1%). Of these, 19 (47.5%) included other significant pathology. Before CT scanning, physicians planned to discharge 115 patients and admit six patients. After CT scanning, six of the former group were admitted, and five of the latter group were discharged. Patients presenting with a first episode of clinically suspected nephrolithiasis should undergo CT scanning because it enhances diagnostic certainty by identifying alternate diagnoses not suspected on clinical grounds alone.     

Validation of emergency physician ultrasound in diagnosing hydronephrosis in ureteric colic

Objective: Patients presenting to the ED with obstructive nephropathies benefit from early detection of hydronephrosis. Out of hours radiological imaging is expensive and disruptive to arrange. Emergency physician ultrasound (EPU) could allow rapid diagnosis and disposition. If accurate it might avert the need for formal radiological imaging, exclude an obstruction and improve patient flow through the ED. Methods: This was a prospective study of a convenience sample of all adult non‐pregnant patients with presumed ureteric colic attending the ED with prior ethics committee approval. An emergency physician or registrar performed a focused ultrasound scan and were blinded to the patient’s other management. A computerized tomography scan was also performed for all patients while in the ED or within 24 h of the EPU. The accuracy of EPU detection of hydronephrosis was determined; using computerized tomography scans reported by a senior radiologist as the ‘gold‐standard’. Results: Sixty‐three patients with suspected ureteric colic were enrolled of whom 57 completed both EPU and computerized tomography imaging. Forty‐nine had confirmed nephrolithiasis by computerized tomography with 39 having evidence of hydronephrosis. Overall prevalence of hydronephrosis was 68% (95% confidence interval [CI] 56–79%); compared with computerized tomography, EPU had a sensitivity of 80% (95% CI 65–89%); specificity of 83% (95% CI 61–94%); positive predictive value of 91% (95% CI 75–98%) and negative predictive value of 65% (95% CI 43–83%). The overall accuracy was 81% (95% CI 69–89%). Conclusion: Although the accuracy of detection of hydronephrosis after focused training in EPU is encouraging, further experience and training might improve the accuracy of EPU and allow its use as a screening tool.     

Teleradiology interpretations of emergency department computed tomography scans

Background: Teleradiologist interpretation of radiographic studies during after-hours Emergency Department (ED) care has the potential to influence patient management. Study Objectives: We sought to characterize frequencies of discrepancies between teleradiology and in-house radiology interpretations for computed tomography (CT) scans. Methods: We conducted a prospective observational study comparing teleradiologist and in-house radiologist interpretations of CT scans obtained between 7:00 p.m. and 7:00 a.m. from the ED at a Level I trauma center. For each scan, discrepancies were characterized as major, minor, or no discrepancy. Follow-up data were used to characterize major discrepancies. Results: Of 787 studies sent to teleradiology, 550 were scans of the head, cervical spine, chest, or abdomen and pelvis. Major discrepancies were identified in 32 of 550 studies (5.8%; 95% confidence interval 4.1%–8.1%), including 7 of 160 head CT scans, 1 of 29 cervical spine CT scans, 3 of 64 chest CT scans, and 21 of 297 abdominopelvic CT scans. We attributed 8 of the 32 major discrepancies to a teleradiology misinterpretation, with one case leading to an adverse event. Conclusions: We identified major discrepancies due to teleradiologist misinterpretation in 8 of 550 studies, with one patient suffering an adverse event. Our findings support the cautious use of teleradiology interpretations.     

Diagnosis and initial management of kidney stones

The diagnosis and initial management of urolithiasis have undergone considerable evolution in recent years. The application of noncontrast helical computed tomography (CT) in patients with suspected renal colic is one major advance. The superior sensitivity and specificity of helical CT allow urolithiasis to be diagnosed or excluded definitively and expeditiously without the potential harmful effects of contrast media. Initial management is based on three key concepts: (1) the recognition of urgent and emergency requirements for urologic consultation, (2) the provision of effective pain control using a combination of narcotics and nonsteroidal anti-inflammatory drugs in appropriate patients and (3) an understanding of the impact of stone location and size on natural history and definitive urologic management. These concepts are discussed with reference to contemporary literature, with the goal of providing tools that family physicians can use in the emergency department or clinic.     

Subarachnoid hemorrhage diagnosis by computed tomography and lumbar puncture: Are fifth generation CT scanners better at identifying subarachnoid hemorrhage?

This study sought to determine the sensitivity and specificity of modern computed tomography (CT) scans for the diagnosis of subarachnoid hemorrhage (SAH). No studies have been done recently with fifth generation CT scanners to look at the diagnosis of SAH. A retrospective chart review was done of Emergency Department (ED), laboratory, and hospital records at Pitt County Memorial Hospital in Greenville, North Carolina over 1 year from January 1, 2002 to December 31, 2002. Patients presented with headache and had a CT scan of the head with a fifth generation multi-detector CT scanner followed by a lumbar puncture (LP) to rule out SAH. There were 177 patients who presented to the ED with headache and went on to have a CT scan and an LP to rule out SAH. No patients who had a negative CT were found to have a subarachoid hemorrhage. It is concluded that fifth generation CT scanners are probably more sensitive than earlier scanners at detecting SAH.     

Use of spiral computed tomography contrast angiography and ultrasonography to exclude the diagnosis of pulmonary embolism in the emergency department

Spiral computed tomography (CT) contrast angiography is a promising imaging modality for the diagnosis of pulmonary embolism but the negative predictive value of this test remains controversial. We performed a multi-center prospective cohort study to determine the safety of relying on a negative spiral CT contrast angiography scan to exclude pulmonary embolism. Patients presenting to the Emergency Departments of three tertiary care institutions with clinically suspected pulmonary embolism were potentially eligible for the study. Patients underwent a clinical evaluation to categorize pretest probability into low, moderate, and high categories, and had D-dimer testing performed. Patients at low pretest probability with normal D-dimer were considered to have pulmonary embolism excluded. The remaining patients underwent spiral CT contrast angiography scan of the pulmonary arterial circulation and bilateral venous ultrasound of the proximal leg veins. Patients who were confirmed to have pulmonary embolism or deep vein thrombosis were treated with anticoagulant therapy. Patients in whom the diagnosis of pulmonary embolism was excluded did not receive anticoagulant therapy and were followed for a 3-month period for the development of venous thromboembolic complications. Eight hundred fifty-eight (858) patients were enrolled in this study. Three-hundred sixty-nine (369) patients had low pretest probability and negative D-dimer results and no further diagnostic tests were performed. None of these patients subsequently developed venous thromboembolic complications (0%, 95% confidence interval [CI] 0% to 1.0%). The remaining 489 were referred for spiral CT contrast angiography scan and ultrasound. Sixty-seven patients were confirmed to have pulmonary embolism and an additional 15 patients with negative CT scans had proximal deep vein thrombosis (DVT) on ultrasound for a total prevalence of venous thromboembolism of 82/489 (16.8%). Two of 409 patients who had pulmonary embolism excluded in the initial evaluation phase developed proximal venous thromboembolism (0.5%; 95% CI 0% to 1.8%) in the 3-month follow-up period. These findings suggest that the combination of a negative spiral CT contrast angiography scan and normal venous ultrasound imaging safely excludes the diagnosis of pulmonary embolism in the Emergency Department setting.     

The incidence and implications of haematuria in renal colic

The aim of the study was to investigate the incidence of haematuria in patients presenting to the emergency department with renal colic, subsequently proven to be due to renal or ureteric calculus. Of 461 files reviewed, 239 satisfied the study criteria. Twenty two of these (9.2%) had no haematuria. Injectable narcotic analgesic was required in 203 of 239 cases whilst the remaining 36 patients received oral analgesic. Analysis of data from the study group as well as two other groups selected from the rejected files showed that the incidence of haematuria was the highest (91%) when patients presented with acute renal colic requiring injectable narcotic analgesic (active state) and was the lowest (47%) for patients admitted for elective management of calculi (quiescent state). Emergency intravenous urogram should be performed in patients presenting with suspected renal colic without haematuria.     

The impact of body mass index on concordance in the interpretation of matched noncontrast and contrast abdominal pelvic computed tomographic scans in ED patients with nontraumatic abdominal pain

OBJECTIVE: To determine if body mass index (BMI) is associated with interpretation agreement between matched abdominal pelvic computed tomographic (CT) scan performed with and without oral contrast in emergency department (ED) patients. METHODS: A prospective observational trial of a convenience sample of 100 adult patients undergoing an abdominal pelvic CT was done at a tertiary care academic ED from September 4, 2001, to August 30, 2002. Patients with trauma, renal colic, pregnancy, need of intravenous contrast, or who were clinically unstable were excluded. Height, weight, and waist circumference were recorded and BMI was calculated. Patients had a helical abdominal pelvic CT without oral contrast followed by two drinks of oral contrast 90 minutes apart and then a repeat CT. Attending staff radiologists interpreted the CT scans using explicit data sheets and were blinded to the results of the matching CT. Clinically important discordance between the matching scans was determined by a panel of attending staff from radiology and emergency medicine departments. RESULTS: Of the 100 patients who completed the protocol, 21% (95% confidence interval, 13%-30%) had clinically significant disagreement between noncontrast and oral contrast CT interpretations. Logistic regression analyses yielded an odds ratio of 1.0 (95% confidence interval, 0.9-1.1) for BMI. CONCLUSIONS: This study did not find an association between BMI, sex, or waist circumference and concordance of radiologists' interpretation of noncontrast and oral contrast abdominal pelvic CT scans in ED patients.