Cost-effectiveness of CTA, MRA and DSA in patients with non-traumatic subarachnoid hemorrhage 133 Introduction Rupture of an intracranial aneurysms is a major cause of death and disability with an overall incidence of approximately 9 out of 100.000.1 In the group of patients who survived initial bleed, the risk of rebleeding without treatment would be 1-2% per day for the first four weeks with a 70% case fatality rate.2,3 To prevent rebleeding from ruptured aneurysms, treatment is performed as soon as feasible in order to exclude the aneurysm from the arterial circulation.2,4,5 Treatment options are either neurosurgical clipping via craniotomy or endovascular aneurysm occlusion by detachable platinum coils. The ISAT trial demonstrated better clinical outcome and significant risk reduction for endovascular treatment. Coiling is the preferred option in patients where both treatments are feasible.2,6-9 Total treatment costs were found to be slightly higher for surgical clipping compared to endovascular coiling.10-13 Non-traumatic subarachnoid hemorrhage (SAH) is caused in about 85% of cases by a ruptured intracranial aneurysm.14 Diagnostic imaging is required to fulfill two tasks: 1. To detect the presence of intracerebral aneurysms. 2. To determine the most suitable treatment: endovascular coiling or surgical clipping. DSA is the reference standard for detecting aneurysms and determing the feasibility of coiling. Nevertheless this invasive and labor intensive technique is relatively expensive and carries discomforts and potential risks.15-18 Promising noninvasive and less costly diagnostic alternatives are CTA and MRA. CTA is easily available and can be rapidly performed in an acute setting. The main benefits of MRA are the fact that no ionizing radiation is used, and the contrast medium injected has less nephrotoxic complications. Although costs and characteristics of diagnostic tests and treatment have been reported, we found no studies determining the optimal diagnostic pathway in patients with suspected ruptured intracranial aneurysms. The goal of our study was to compare the cost-effectiveness of MRA, CTA and DSA in these patients for the first year’s period after the bleed. Cost-effectiveness of diagnostic tests in follow-up of coiled aneurysm has previously been evaluated by Schaafsma et al.19 MaterialsandMethods The results of Chapter 2 and 3 of this thesis are used as input parameters. 75 patients with non- traumatic SAH were included.20 For all patients, MRA, CTA and DSA had been performed. Details of the patient population and scan parameters can be found in Chapter 2. For each diagnostic test, two experienced observers determined the presence of an aneurysm and feasibility of endovascular coiling. The observers were blinded to the parallel imaging modality and to the results of each other’s findings. Pooled sensitivity of CTA for detection of aneurysms was 91.5% (95% CI: 85.0-95.5) and specificity was 94.4% (95% CI: 79.0-99.0). Pooled sensitivity of MRA for detection of aneurysms was 95.4% (95% CI: 89.8-98.1) and specificity was 83.3% (95% CI: 66.5-93.0). Pooled sensitivity of CTA in determining feasibility of endovascular coiling was 71.9% (95% CI: 59.0-82.1) and specificity was 75.4% (95% CI: 62.0-85.5). Pooled sensitivity of MRA in determining feasibility of endovascular coiling was 60.6% (95%
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