Pulmonary 64-MDCT angiography with 30 mL of IV contrast material: vascular enhancement and image quality.

OBJECTIVE: The objective of our study was to determine whether vascular enhancement and image quality can be preserved in pulmonary CT angiography (CTA) performed on a 64-MDCT scanner with 30 mL of IV contrast material. MATERIALS AND METHODS: This retrospective matched-cohort study compared image quality of pulmonary CTA performed using 30 mL of IV contrast material versus 100 mL of IV contrast material. CT images of 50 patients (46 men, four women; mean age, 66 years) who underwent pulmonary CTA on a 64-MDCT scanner using a low dose (30 mL) of iodixanol 320 and another 50 patients (49 men, one woman; mean age, 65 years) who underwent pulmonary CTA using a regular dose (100 mL) of contrast material during the same time period were selected for review. The 30- and 100-mL pulmonary CTA studies were retrospectively evaluated by two thoracic radiologists in random order. Attenuation values were recorded over the main, right main, selected lobar, segmental, and subsegmental pulmonary arteries. Image quality was also subjectively assessed using visual scores on a scale from 1 (nondiagnostic) to 5 (excellent). RESULTS: The average attenuation measurements of the main, right main, selected lobar, segmental, and subsegmental pulmonary arteries were 260, 262, 280, 316, and 338 HU, respectively, on the 30-mL studies and 313, 301, 316, 344, and 349 HU, respectively, on the 100-mL studies. The average visual score was 4.0 for both the 30- and 100-mL groups. A visual score of 4 or 5 was given to 82% of studies in the 30-mL group and 78% of studies in the 100-mL group. CONCLUSION: Contrast agent dose for pulmonary CTA using a 64-MDCT scanner can be significantly reduced without compromising diagnostic image quality.

Does a clinical decision rule using D-dimer level improve the yield of pulmonary CT angiography?

OBJECTIVE: The objective of our study was to evaluate the impact of incorporating a mandatory clinical decision rule and selective d-dimer use on the yield of pulmonary CT angiography (CTA). MATERIALS AND METHODS: Guidelines incorporating a clinical decision rule (Wells score: range, 0-12.5) and a highly sensitive d-dimer assay as decision points were placed into a computerized order entry menu. From December 2006 through November 2008, 261 pulmonary CTA examinations of 238 men and 14 women (mean age ± SD, 65 ± 12 years; range, 31-92 years) were performed. Eight patients underwent more than one pulmonary CTA examination. Charts were reviewed. The results of pulmonary CTA, the clinical decision rule, and d-dimer level (if obtained) were analyzed with the Student t test, chi-square test, or other comparisons using statistical software (MedCalc, version 11.0). RESULTS: Of the pulmonary CTA examinations, 16.5% (43/261) were positive for pulmonary embolism (PE) compared with 3.1% (6/196) during the previous 2 years. The mean clinical decision rule score and mean d-dimer level were 5.5 ± 2.4 (SD) and 4956 ± 2892 ng/mL, respectively, for those with PE compared with 4.5 ± 2.1 and 2398 ± 2100 ng/mL for those without PE (both, p < 0.01). The negative predictive value of a clinical decision rule score of 4 or less and d-dimer level of less than 1000 ng/mL was 1.0. A clinical decision rule of greater than 4 and a higher d-dimer level were better predictors for PE, especially a d-dimer level of greater than 3000 ng/mL (odds ratio = 6.69; 95% CI = 2.72-16.43). CONCLUSION: Guidelines combining a clinical decision rule with d-dimer level significantly improved the utilization of pulmonary CTA and positive yield for PE.

Long-Term Experience With a Mandatory Clinical Decision Rule and Mandatory d-Dimer in the Evaluation of Suspected Pulmonary Embolism.

PURPOSE: This study evaluated the long-term effectiveness of mandatory assignment of both a clinical decision rule (CDR) and highly sensitive d-dimer in the evaluation of patients with suspected pulmonary embolism (PE). MATERIALS AND METHODS: Institutional guidelines with a CDR and highly sensitive d-dimer were embedded in an order entry menu with mandatory assignment of key components before ordering a CT pulmonary angiogram (CTPA). Data were retrospectively extracted from the electronic health record. RESULTS: This was a retrospective review of 1,003 CTPA studies (905 patients, 845 male and 60 female patients, age 63.7 ± 13.5 years). CTPAs were positive for PE in 170 studies (17%), representing an average yield of 15% (year [average]; 2007 [15%], 2008 [18%], 2009 [15%], 2010 [15%], 2011 [17%], 2012 [15%], 2013 [23%]). The increased yield represented efforts of mandatory order entry assignments, educational sessions, and clinical champions. Different d-dimer thresholds with or without age adjustments in combination with the CDR identified about 10% of patients who may have been managed without CTPA. CONCLUSION: Mandatory assignment of a CDR and highly sensitive d-dimer clinical decision pathway can be successfully incorporated into an order entry menu and produce a sustained increase in CTPA yield of patients with suspected PE.

Contralateral decubitus positioning enhances computed tomographic angiographic evaluation of pulmonary vasculature in a patient with a pulmonary arteriovenous malformation.

Computed tomographic pulmonary angiography has become the diagnostic procedure of choice in patients suspected of having a pulmonary embolus. However, intrapulmonary shunting of blood in a variety of pathologic conditions can cause suboptimal opacification of the pulmonary arterial circulation and result in a suboptimal or even nondiagnostic study. Radiologists should be aware of these conditions and be familiar with positioning techniques to minimize such shunting. We report a patient suspected of having pulmonary embolism, in whom a preexisting unilateral arteriovenous malformation prevented adequate evaluation of the pulmonary circulation. Positioning the patient in the contralateral decubitus position significantly enhanced image quality.

Use of coronary computed tomography angiography to detect coronary ostial stenosis after Bentall procedure.

Coronary ostial stenosis is a rare complication of the Bentall procedure for aortic root and aortic valve replacement. We report a case of coronary ostial stenosis after a Bentall procedure that was detected by coronary computed tomography angiography and subsequent percutaneous coronary interventions.

Absence of the left brachiocephalic vein with venous return through the left superior intercostal vein: CT findings.

Asymptomatic congenital thoracic venous anomalies are becoming clinically more relevant with the increasing utilization of minimally invasive surgical vascular procedures, such as left-sided implantable cardioverter defibrillator implantation. The purpose of this report is to describe the computed tomography findings of the congenital absence of the left brachiocephalic vein in a patient with no evidence of congenital cardiovascular disease and no prior history of central venous instrumentation. In this patient, the left internal jugular and the left subclavian veins drain via the left superior intercostal vein, the accessory hemiazygous, the hemiazygous, and the azygous vein into the right brachiocephalic vein to form the superior vena cava. The clinical significance and possible embryogenesis of this anomaly are discussed.