Sensitivity Of Helical Computed Tomography Research Articles

Validation of helical computed tomography for suspected pulmonary embolism: a near miss?

In this issue of the Journal of Thrombosis and Haemostasis, van Strijen et al. report the results of a study designed to establish the performance of single-detector helical computed tomography (CT) for diagnosing pulmonary embolism (PE) [1]. The main finding of those authors is the poor 69% sensitivity of helical CT (i.e. an around 30% false-negative rate), which is hardly reassuring for a test increasingly used as a stand-alone imaging modality. The history of the rapid uptake of helical CT in the field of PE [2,3] is exemplary in many respects.

Occlusive arterial disease of abdominal aorta and lower extremities: Comparison of helical CT angiography with transcatheter angiography

The purpose of this study was to evaluate helical CT angiography in the assessment of occlusive arterial disease of abdominal aorta and the lower extremities. Sixteen patients underwent both transcatheter angiography and helical CT. Helical CT was inconclusive in 6.2% of segments whereas angiography was inconclusive in 5%. The overall sensitivity of helical CT was 91% and specificity 93%. Segmental analysis found a sensitivity of 43% in infrapopliteal arteries, and a specificity of 86%.

Performance of helical computed tomography in unselected outpatients with suspected pulmonary embolism.

Helical computed tomography (CT) is commonly used to diagnose pulmonary embolism, although its operating characteristics have been insufficiently evaluated. To assess the sensitivity and specificity of helical CT in suspected pulmonary embolism. Observational study. Emergency department of a teaching and community hospital. 299 patients with clinically suspected pulmonary embolism and a plasma D -dimer level greater than 500 microgram/L. Pulmonary embolism was established by using a validated algorithm that included clinical assessment, lower-limb compression ultrasonography, lung scanning, and pulmonary angiography. Sensitivity, specificity, and likelihood ratios of helical CT and interobserver agreement. Helical CT scans were withheld from clinicians and were read 3 months after acquisition by radiologists blinded to all clinical data. 118 patients (39%) had pulmonary embolism. In 12 patients (4%), 2 of whom had pulmonary embolism, results of helical CT were inconclusive. For patients with conclusive results, sensitivity of helical CT was 70% (95% CI, 62% to 78%) and specificity was 91% (CI, 86% to 95%). Interobserver agreement was high (kappa = 0.823 to 0.902). The false-negative rate was lower for helical CT used after initial negative results on ultrasonography than for helical CT alone (21% vs. 30%). Use of helical CT after normal results on initial ultrasonography and nondiagnostic results on lung scanning had a false-negative rate of only 5% and a false-positive rate of only 7%. Helical CT should not be used alone for suspected pulmonary embolism but could replace angiography in combined strategies that include ultrasonography and lung scanning.

Traumatic rupture of the aortic isthmus: program of selective management.

Two hypotheses were investigated: (1) helical computed tomography (CT) of the chest on victims of decelerating trauma can yield a diagnosis of, or "rule out," a traumatic rupture of the aorta (TRA) without the need for an aortogram; and (2) selective delay of aortic repair can be safely accomplished through a medical management protocol. Screening helical CT examinations were done on 6169 victims of blunt thoracic trauma; 47 were found to have TRA; in 8, indirect but nondiagnostic findings not clarified by an aortogram led to surgical exploration. The sensitivity of helical CT was higher than that of aortograms, and a "normal" helical CT scan was never associated with a proved TRA. It is estimated that the use of helical CT has resulted in at least a 40% to 50% decrease in the need for aortograms, in addition to yielding rapid, noninvasive valuable information about other injuries. Drugs (beta-blockers +/- vasodilators) to decrease the stress in the aortic wall were used in 93 patients when the diagnosis was suspected and were continued as necessary through the evaluation, stabilization, and until the aorta was cross-clamped at operation. Elective, delayed operation was done between 2 days and 25 months in 15 patients who were deemed to be excessive risks for emergency aortic repair; there were 2 deaths (13. 3%). Eleven patients never had aortic repair. No patient maintained on this protocol, whether repaired emergently, electively, or not at all, developed free rupture of the periaortic hematoma and death from TRA.