24 Chapter 1 This report is described in Chapter 5: Single-center experience of surgical and endovascular treatment of ruptured intracranial aneurysms. Recurrence and rebleed after treatment Although the aim of treating aneurysms after a SAH is to prevent rebleeds, these do occur, mostly in the first weeks after treatment. Early rebleed incidence (within 30 days after endovascular treatment of ruptured aneurysms) is reported to be between 1.1 and 3.6%.387-389 The main risk factors for early rebleed are larger aneurysms and the presence of intracerebral hematoma (ICH), incomplete aneurysm occlusion by coils being a lesser factor.387-389 Late rebleed incidence is lower, with an annual rate between 0.1 and 0.3%,323,390,391 and incomplete aneurysm occlusion is a strong predictor of late rebleed.323,390-393 Since repeat treatment of recurrences involves relatively little risk,391,394-396 it is recommended that patients with treated aneurysms be followed in order to detect recurrences, and that these recurrences should be treated.392 Follow-up of coiled aneurysms Until recently, DSA was the established post-coiling standard of reference for aneurysm evaluation. Whereas it is true that CTA images suffer too much from beam hardening artefacts caused by the coil mesh,397 MRA is potentially a good alternative: the platinum coils are compatible with MR imaging in terms of safety and do not produce image artefacts at magnetic field strengths up to 3 Tesla.398-400 The first reports on the use of MRA for coiled aneurysm follow-up were published at the end of the last century.401-405 These first studies were all performed with flow-dependent MRA sequences incurring the potential disadvantages described in the aneurysm detection section above. Studies using contrast enhanced TOF sequences followed, but this did not improve performance.406-409 First-pass or ultra-fast CEMRA sequences appeared in few studies to be superior to flow-dependent MRA,410-412 but in another study no such superiority was found.413 Two meta-analyses on the diagnostic accuracy of MRA in the detection of recurrences after endovascular coiling were published one shortly after the other: Kwee and Kwee414 and Weng et al.415 Kwee and Kwee evaluated 16 studies, all with DSA as standard of reference, and evaluated TOF MRA and CEMRA data separately. However, the CEMRA data included studies using contrast-enhanced TOF as well as true first pass CEMRA: of the seven studies providing CEMRA data, only two410,411 used first- pass CEMRA. Pooled estimates of sensitivity and specificity were found to be 83.3 and 90.6% for non- enhanced TOF MRA, and 86.6 and 91.9% for the mixed “CEMRA” group. Thus Kwee and Kwee found slightly but not significantly better results for the mixed “CEMRA” group than for non-enhanced TOF MRA. Weng et al415 also evaluated 16 studies, largely overlapping with Kwee and Kwee’s meta-analysis. They performed the same analysis on TOF and CEMRA data, using the same mix of CEMRA data as Kwee and Kwee: from the six studies providing CEMRA data, only three had used true first-pass CEMRA.410,411,413 The authors found pooled sensitivity and specificity of 90 and 95% for non-enhanced TOF MRA, and 92 and 96% for CE-TOF/CEMRA. Again the difference was not significant.
proefschrit Van Zwam inhoud met kaft en stellingen.indd
To see the actual publication please follow the link above