Diagnosis of pulmonary embolism and the underlying venous thrombosis by multi-slice CT.

Aim: To determine the value of multi-slice CT for the diagnosis of acute pu lmonary embolism and an underlying venous thrombosis. Methods: 70 patients with clinically suspected acute pulmonary embolism were examined. Using mul ti-slice CT a combined examination of the pulmonary arteries and the veins of the lower limb, pe(vis and abdomen was performed. Only one single bo[us of 150 ml iopromid 300 was injected into a cubital vein with a flow of 4 ml /s. First, the pulmonary arteries were scanned with a slice thickness of 2. 5 mm and a pitch of 1.5. On arrival of the contrast medium at the popliteal veins, indicated by bolus trakking, the veins of the lower limbs up to the end of the inferior vena cava were imaged using a slice thickness of 3.75 mm and a pitch of 1.5. The results could be compared with a ventilation-per fusion scan in 48 cases, with a Doppler ultrasound examination in 46 cases, and with a venography in 70 cases. Furthermore, the image quality of all a rterial and Venous regions was subjectively assessed. Results: in all patie nts who underwent multi-slice CT the pulmonary arteries as well as the vein s of the lower half of the body could be recorded completely. Regarding the pulmonary arteries the image quality showed excellent results for the cent ral and segmental arteries. The region up to the 3rd division in subsegment al branches could be sufficiently judged. More peripherally, a diagnostic a ssessment was not possible. The image quality of the veins was excellent in all sections, except the calf, where a reliable diagnosis could not be mad e. The comparison with the other techniques confirmed the superiority of mu lti-slice CT concerning the central and segmental pulmonary arteries and th e veins from the popliteal vein to the inferior vena cava. In contrast, per ipheral pulmonary emboli can be detected more certainly in ventilation/perf usion scans. The veins of the calf can be evaluated more reliably with veno graphy. Conclusion: Multi-slice CT proved to be an outstanding tool in the diagnosis of acute pulmonary embolism. The clinically suspected disease and a causing venous thrombosis can be detected in a fast and reliable way. At present, multi-slice CT is not suitable for the recognition of peripheral emboli. However, expected technical developments hold promise for future im provements.