Size-appropriate radiation doses in pediatric body CT: a study of regional community adoption in the United States.

BACKGROUND: During the last decade, there has been a movement in the United States toward utilizing size-appropriate radiation doses for pediatric body CT, with smaller doses given to smaller patients. OBJECTIVE: This study assesses community adoption of size-appropriate pediatric CT techniques. Size-specific dose estimates (SSDE) in pediatric body scans are compared between community facilities and a university children's hospital that tailors CT protocols to patient size as advocated by Image Gently. MATERIALS AND METHODS: We compared 164 pediatric body scans done at community facilities (group X) with 466 children's hospital scans. Children's hospital scans were divided into two groups: A, 250 performed with established pediatric weight-based protocols and filtered back projection; B, 216 performed with addition of iterative reconstruction technique and a 60% reduction in volume CT dose index (CTDIvol). SSDE was calculated and differences among groups were compared by regression analysis. RESULTS: Mean SSDE was 1.6 and 3.9 times higher in group X than in groups A and B and 2.5 times higher for group A than group B. A model adjusting for confounders confirmed significant differences between group pairs. CONCLUSIONS: Regional community hospitals and imaging centers have not universally adopted child-sized pediatric CT practices. More education and accountability may be necessary to achieve widespread implementation. Since even lower radiation doses are possible with iterative reconstruction technique than with filtered back projection alone, further exploration of the former is encouraged.

CT angiography in the evaluation of acute pulmonary embolus.

OBJECTIVE: The purpose of this study was to assess the appropriate use of CT angiography (CTA) in the diagnostic evaluation of acute pulmonary embolism (PE). MATERIALS AND METHODS: We reviewed a total of 575 CT angiograms obtained to evaluate for PE at a large level 1 trauma teaching hospital from January 2004 through March 2005. Various clinical settings were used for 267 inpatient (46%), 258 emergency department (45%), and 50 outpatient (9%) studies. We excluded CTA performed for other reasons, repeated CTA, and patient records with incomplete clinical data. On the basis of chart review in which the investigators were blinded to final diagnoses, pretest probability of PE according to the Wells criteria was retrospectively assigned to each patient. D-dimer values, when obtained, also were reviewed. The diagnosis of PE was based on final CTA reports. RESULTS: PE was diagnosed in 9.57% of 575 patients. Positivity rates by location were 32 (12%) of the 267 inpatients, 22 (8.5%) of the 258 emergency department patients, and one (2.0%) of the 50 outpatients. Three (< 1%) of the 575 patients had high probability of PE, even though 351 patients had gone directly to CTA. Of the other 572 patients, 158 (28%) had intermediate and 414 (72%) low probability of PE. In the high, intermediate, and low probability groups, two (67%), 24 (15%), and 29 (7%), respectively, of the patients had PE. A D-dimer assay was performed for 224 (39%) of the 575 patients. Thirty-nine (17%) of the 224 patients had normal results (< 0.5 microg/mL); 107 (48%), intermediate results (0.6-2.0 microg/mL); and 78 (35%), abnormal results (> 2.0 microg/mL). In the emergency department cohort, 151 (59%) of 258 patients underwent a D-dimer assay. Thirty-two (21%) of the 151 patients had normal results; 81 (54%), intermediate results; and 38 (25%), abnormal results. Only one patient with a normal D-dimer level and three patients with intermediate D-dimer levels had PE, the equivalent of 3% of each group. The number of CTA examinations ordered for patients with normal and intermediate D-dimer results was 146 (25% of the 575 total studies). Twenty-two (8%) of the 258 emergency department patients had PE, and clinical suspicion of PE was high for 11 (50%), intermediate for 10 (45%), and low for one (5%) of those patients. CONCLUSION: Our data showed suboptimal use of the Wells criteria and subjective overestimation of the probability of PE before ordering of CTA. Although a definitive acceptable PE positivity rate for CTA has not been established, the 10% yield represents overuse of CTA as a screening rather than a diagnostic examination.

Short-term femoral vein catheterization rarely causes thrombosis or bacteremia.

BACKGROUND: Experts and national regulatory bodies have deemed femoral vein catheterization (FVC) unsafe, and recommend avoiding it whenever possible. OBJECTIVE: To assess rates of catheter-related bloodstream infections (CRBI) and deep venous thrombosis (DVT) complicating FVC. DESIGN: Prospective observational cohort study. SETTING: Medical intensive care unit (MICU) of a 350-bed community teaching hospital. PATIENTS: Consecutive admissions to the MICU during 7 months. METHODS: Demographic, laboratory and Doppler ultrasound studies were collected on patients receiving large vein catheters (VC) in our MICU. Ultrasound examinations were systematically performed on the day of and 5 to 7 days after removal of FVC. RESULTS: VC were inserted in 238 (35% of) patients. Of that total, 217 catheters were in large veins (49% FVC, 38% internal jugular and 13% subclavian) for an average of 2.7 days for femoral, 5.7 days for internal jugular and 3.6 days for subclavian vein catheters. During 1200 catheter-days, no central VC CRBI was identified. Of 107 FVC, initial and follow-up Doppler studies were performed in 50 patients. A total of 97% of patients received routine thromboprophylaxis and none had a DVT. Of the 57 patients with initial but no Doppler follow-up at 5 to 7 days following removal, no patient developed clinically detected venous thromboembolism (VTE). CONCLUSION: Short-term FVC was used safely in our MICU in the setting of thromboprophylaxis. In light of its favorable safety profile for initial resuscitation of critically ill patients, it may be premature to strongly discourage FVC.