Simulation study employing different scenarios 83 On the other hand, when a coiling procedure is unsuccessfully attempted for an aneurysm which is in fact not suitable for endovascular treatment, the patient undergoes a procedure under general anesthesia which would not have been necessary if a diagnostic DSA study had been performed earlier. With regard to the risk of DSA, these studies pose relatively little hazard to the patient, with morbidity and mortality rates of 0.14 and 0.06% respectively (although the presence of SAH has been associated with an increased risk).3 Only a few reports on cerebral aneurysm detection by CEMRA have been published6,7,9,25,26 and to our knowledge no study has been published to date addressing the question whether CEMRA can be used for treatment planning. An alternative technique to CEMRA is CTA. This technique has some disadvantages compared to CEMRA, as ionizing radiation is employed, while X-ray contrast media are considered to be more invasive than MR contrast media. The accuracy of aneurysm detection by CTA has been described in two meta- analyses.27,28 There are few reports in the literature describing the accuracy CTA in deciding whether endovascular treatment is possible.29-32 One study, using CTA as the only pretreatment modality for aneurysm detection and treatment planning, states that in only 18% (41/223) of patients with an aneurysm was an additional DSA study needed for treatment planning.30 The report does not mention however whether all the decisions on treatment mode made on the basis of CTA were correct. Other studies report strategies using CTA as a pretreatment modality,33-37 but none specify the accuracy in guiding the decision whether to perform endovascular treatment or not. CTA has the logistical advantage that it can be performed directly following a diagnostic CT study aimed at detecting the presence of blood in the subarachnoid cisterns, without the need to transport the patient. Conclusion Diagnostic strategy in patients who have undergone a SAH and are suspected of harboring an intracranial aneurysm must focus on accurate detection and reliable morphologic classification of the aneurysm in order to assist selection of the preferred type of treatment: endovascular coiling or surgical clipping. Given the higher cost and more invasive nature of DSA, several strategies using a technique such as CEMRA can be employed. The present study indicates that acceptable results can be achieved by performing CEMRA as the first study, and reserving DSA for cases in which CEMRA produces a negative result or leaves room for doubt in patients who are to be referred for surgical clipping. References 1 Dawkins, A. A. et al. Complications of cerebral angiography: a prospective analysis of 2,924 consecutive procedures. Neuroradiology 49, 753-759, (2007). 2 Fifi, J. T. et al. Complications of modern diagnostic cerebral angiography in an academic medical center. J Vasc Interv Radiol 20, 442-447, (2009).
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