Comparison of Imaging Strategies with Conditional versus Immediate Contrast-Enhanced Computed Tomography in Patients with Clinical Suspicion of Acute Appendicitis.

OBJECTIVES: To compare the diagnostic accuracy of conditional computed tomography (CT), i.e. CT when initial ultrasound findings are negative or inconclusive, and immediate CT for patients with suspected appendicitis. METHODS: Data were collected within a prospective diagnostic accuracy study on imaging in adults with acute abdominal pain. All patients underwent ultrasound and CT, read by different observers who were blinded from the other modality. Only patients with clinical suspicion of appendicitis were included. An expert panel assigned a final diagnosis to each patient after 6 months of follow-up (clinical reference standard). RESULTS: A total of 422 patients were included with final diagnosis appendicitis in 251 (60 %). For 199 patients (47 %), ultrasound findings were inconclusive or negative. Conditional CT imaging correctly identified 241 of 251 (96 %) appendicitis cases (95 %CI, 92 % to 98 %), versus 238 (95 %) with immediate CT (95 %CI, 91 % to 97 %). The specificity of conditional CT imaging was lower: 77 % (95 %CI, 70 % to 83 %) versus 87 % for immediate CT (95 %CI, 81 % to 91 %). CONCLUSION: A conditional CT strategy correctly identifies as many patients with appendicitis as an immediate CT strategy, and can halve the number of CTs needed. However, conditional CT imaging results in more false positives. KEY POINTS: • Conditional CT (CT after negative/inconclusive ultrasound findings) can be used for suspected appendicitis. • Half the number of CT examinations is needed with a conditional strategy. • Conditional CT correctly identifies as many patients with appendicitis as immediate CT. • Conditional imaging results in more false positive appendicitis cases.

CT evaluation of chronic thromboembolic pulmonary hypertension.

The educational objectives of this article are to provide an overview of the computed tomography (CT) findings in chronic thromboembolic pulmonary hypertension. This article reviews the key imaging findings at CT in patients with chronic thromboembolic pulmonary hypertension. After reading this article, the reader should have an improved awareness of the condition, its imaging features, and the CT imaging features associated with surgically accessible disease.

Real-Time 3D fluoroscopy guidance during needle interventions: technique, accuracy, and feasibility.

OBJECTIVE: Real-time 3D fluoroscopy guidance using cone beam CT with dedicated needle path planning software is a promising new interventional technique. The objective of this study was to evaluate the procedure and to assess the accuracy and feasibility of this technique for use in needle interventions. SUBJECTS AND METHODS: All procedures were performed using a flat panel-based fluoroscopy system capable of acquiring cone beam CT images and dedicated needle path-planning software. This new technology allows the use of fluoroscopy coregistered with a 3D data set reconstructed from the acquired attenuation information. The needle trajectory is planned in the 3D data set using the needle path-planning software. The calculated trajectory is then projected on to the real-time fluoroscopy image. Fluoroscopy time, accuracy, technical success of the procedures, median procedure time, and complications were recorded in 145 interventions. RESULTS: One hundred forty-five needle interventions were performed in 139 patients using real-time 3D fluoroscopy guidance. Procedures were divided into five groups according to anatomic region: upper thoracic (n = 19; 13.1%), lower thoracic (n = 18; 12.4%), upper abdominal (n = 65; 44.8%), lower abdominal (n = 13; 9.0%), and musculoskeletal (n = 30; 20.7%). Thirty needle interventions were therapeutic, and 115 were diagnostic biopsies. All interventions were within the predefined 5-mm safety margin and achieved 100% technical success. A histopathologic diagnosis could be made in 91.4% of the diagnostic biopsies. The median interventional procedure time was 28.5 minutes, and the median fluoroscopy time was 2 minutes 58 seconds. There were minor complications in six patients (4.3%) and one major complication (0.7%). CONCLUSION: Real-time 3D fluoroscopy guidance is a new, promising, and feasible technique providing high accuracy in needle interventions.

[Optimal patient position for catheterisation of the subclavian vein: in the Trendelenburg position without a rolled towel between the shoulder blades]. / Optimale positie van de patiënt bij katheterisatie van de V. subclavia: in Trendelenburgligging, zonder rol tussen de schouderbladen.

OBJECTIVE: To determine the optimal patient position for subclavian-vein catheterisation. DESIGN: Descriptive. METHOD: The anteroposterior diameter of the right and left subclavian vein was measured using B-mode ultrasound in 26 healthy volunteers lying in 4 different positions: horizontally with or without a rolled towel between the should blades, or in the Trendelenburg position with or without a rolled towel. RESULTS: The mean diameter of the subclavian vein was 10.7 mm. There was a statistically significant association between the diameter of the vein and the position of the volunteer, the use of the rolled towel, and the side of the body. The least favourable results were obtained on the left side when the patient was lying horizontally with a rolled towel (8.65 mm). The most favourable results were obtained on the right side when the patient was in the Trendelenburg position without a rolled towel (12.05 mm). CONCLUSION: For successful catheterisation of the subclavian vein, the patient should be placed in the Trendelenburg position without a rolled towel between the shoulder blades, and the puncture should be preferably on the right side.