78 Chapter 4 possible the number of DSA examinations performed in these patients while maintaining an acceptable level of diagnostic accuracy for aneurysm detection as well as assessment of suitability of the aneurysm for endovascular coiling. Beside the reduction of risk, when CEMRA is used, there is also a cost saving.13,19 In the present study four diagnostic scenarios employing various combinations of CEMRA and DSA are compared with regard to diagnostic accuracy as well as costs. MaterialsandMethods Study design The study made use of the CEMRA and DSA imaging data which had been acquired in 75 consecutive patients presenting with a SAH, in a study assessing the validity of CEMRA in the detection and workup to treatment of patients suspected of harboring an intracranial aneurysm (see Chapters 2 and 3). In the study the following four scenarios are compared with regard to firstly the effect of each scenario on treatment, and secondly to the costs generated by the different scenarios: Scenario 1: All patients undergo only DSA. Selection of best treatment (endovascular coiling or surgical clipping) is based on the DSA findings. Scenario 2: All patients first undergo CEMRA, and the selection of best treatment is based on the CEMRA findings. Only if no aneurysm is found will additional DSA be performed. Scenario 3: All patients first undergo CEMRA. If no aneurysm is found or if there is doubt about the best treatment on the basis of CEMRA findings, additional DSA will be performed. Scenario 4: All patients first undergo CEMRA. If no aneurysm is found or if there is doubt about the best treatment in the group allocated to surgical clipping, additional DSA will be performed in this group. All patients allocated to endovascular coiling on the basis of the CEMRA findings will go directly for coiling. To assess these four scenarios we asked two observers, a neuro-interventionist and a neurosurgeon, both experienced in treating cerebral aneurysms, to evaluate jointly the CEMRA studies of the patients harboring one or more aneurysms. The observers were asked to make a decision in consensus about the feasibility of endovascular treatment of the aneurysm. In a separate session all the DSA studies performed in these patients, either before treatment or as part of the coiling procedure, had previously also been blindly evaluated by the two observers in consensus. These DSA findings were regarded as the standard of reference. If the quality of the CEMRA study in a given patient was insufficient or if for other reasons the observers were not sure about their decision they could request access to the findings of the “gold standard” DSA study performed in that patient. In this way the four scenarios could be simulated with the same observers evaluating both modalities. Patients Patient characteristics are described in Chapter 2. There are two alterations in the number of aneurysms that are described in Chapter 2. One aneurysm had been detected by CEMRA but the finding was not confirmed at the first DSA study because of temporary aneurysm thrombosis, and therefore regarded as a false positive CEMRA finding. A second DSA examination however confirmed the CEMRA finding of an
proefschrit Van Zwam inhoud met kaft en stellingen.indd
To see the actual publication please follow the link above