No abstract

A method for cardio-thoracic multislice spiral CT imaging with ECG gating for suppression of heart pulsation artifacts is introduced. The proposed technique offers extended volume coverage compared with standard ECG-gated spiral scan and reconstruction approaches for cardiac applications: Thin-slice data of the entire thorax can be acquired within one breath-hold period using a four-slice CT system. The extended volume coverage is enabled by a modified approach for ECG-gated image reconstruction. For a CT system with 0.5-s gantry rotation time, images are reconstructed with 250-ms image temporal resolution. Instead of selecting scan data acquired in exactly the same phase of the cardiac cycle for each image as in standard ECG-gated reconstruction techniques, the patient's ECG signal is used to omit scan data acquired during the systolic phase of highest cardiac motion. With this approach cardiac pulsation artifacts in CT studies of the aorta, of paracardiac lung segments, and of coronary bypass grafts can be effectively reduced.

Volume and mass indexes are superior to the traditional score, density, and number of lesions for comparing the results of electron beam and multirow detector CT and for determining significant coronary artery disease.

With the introduction of multi detector-row CT (MDCT), computed tomography (CT) has been firmly established as the de facto first line test for imaging patients with suspected pulmonary embolism (PE). However, remaining concerns regarding CT's accuracy for diagnosis of isolated peripheral emboli have prevented the unanimous acceptance of this test as the standard of reference for imaging PE. Consequently, many patients with a chest CT scan negative for PE undergo additional testing for a definitive rule-out of PE, increasing radiation burden, risk of complications, and health care cost. After a decade of uncertainty, there is now conclusive evidence that computed tomography (CT), if positive, provides reliable confirmation of the presence of PE and, more importantly, if negative effectively rules out clinically significant PE. Current endeavors to streamline and facilitate workflow for CT diagnosis of PE will further improve the acceptance, utility, and importance of this test. Thus, rather than seeking further confirmation for the accuracy of CT for PE diagnosis, future efforts ought to be directed at harnessing the unique strengths of this test. Examples include improvements in workflow, CT derivation of right ventricular function parameters for triage and prognostication of patients with acute PE, and the comprehensive assessment of patients with acute chest pain for PE, coronary disease, aortic disease, and pulmonary disease by means of a single, contrast enhanced, ECG-synchronized CT scan. At the same time, efforts must be directed at refining clinical pathways to ensure appropriate use and avoid overutilization of this test.

No abstract