Purpose: To test whether the prognosis of systemic thrombolysis can be estimated with the attenuation values of vascular occlusions as measured with multi-slice computed tomography (MSCT).
Methods: Prior to thrombolysis with rt-PA, the attenuation values of vascular occlusions were determined with a helical MSCT using a collimation of 0.5 mm. We examined 5 patients that were 63 - 79 years old. With the help of reference values that were obtained from a phantom study we categorised the vascular occlusions according to their attenuation values as being mixed thrombi with low or high proportions of erythrocytes, or red thrombi. TOF angiographies were done before and after the thrombolytic therapy.
Results: The systemic therapy with rt-PA was effective in vascular occlusions that had attenuation values of red thrombi or of mixed thrombi with a high proportion of erythrocytes. The therapy showed no effect when the attenuation values matched with mixed thrombi with a low proportion of erythrocytes. Due to artefacts that were caused by beam hardening, attenuation measurements could not be performed in the posterior fossa.
Conclusion: The presented cases are in accordance with the results of experimental studies which indicate that the efficacy of thrombolysis increases with the attenuation values of thromboembolic vascular occlusions. The predictive value of attenuation measurements by MSCT for the prognosis of systemic thrombolysis cannot be given yet.