102 Chapter 6 Abstract ObjectiveǣTo evaluate the performance of contrast enhanced MRA (CEMRA) at 1.5T in the follow-up of coiled intracranial aneurysms, with digital subtraction angiography (DSA) as the standard of reference. Materials and methods: This is a single-center study, including patients who had been treated by endovascular coiling of one or more intracranial aneurysms and were scheduled for routine follow-up. In addition to the scheduled DSA study participants all underwent CEMRA after giving written informed consent. The interval between DSA and CEMRA was less than 24 hours. Test characteristics of CEMRA were calculated for assessing the occlusion grade of aneurysms according to the Roy and Raymond (R&R) classification, with DSA as the standard of reference. Change in aneurysm occlusion grade in comparison with the initial post-coiling result was evaluated. CEMRA studies were evaluated by two independent observers interactively on a dedicated workstation. In case of discordant results, consensus was reached after joint re-evaluation by both observers. Results: Sixty-nine patients with 74 aneurysms were included. Fourteen of these patients, harboring 17 aneurysms, were studied at six months as well as eighteen months after coiling, resulting in a total of 91 aneurysm assessments. Adequate aneurysm occlusion (Roy and Raymond (R&R) class 1 and 2) was seen at DSA in 69 assessments (75.8%). Sensitivity with 95% confidence interval (CI) for detecting inadequate aneurysm occlusion (R&R class 3) was 81.8% (95% CI: 65.7 – 97.9), specificity was 55.1 (95% CI: 43.4 – 66.8) and negative and positive predictive values were 90.5% (95% CI: 81.6 – 99.4) and 36.7% (95% CI: 23.2 – 50.2) respectively. Linear weighted Kappa for interobserver agreement was 0.57 (95% CI: 0.43 – 0.72). The results did not differ significantly when calculated for detecting any aneurysm remnant (R&R class 2 and 3), nor when calculated for only a single follow-up assessment per patient. Conclusion: CEMRA can be used for the follow-up of coiled aneurysms. When CEMRA shows complete aneurysm occlusion a recanalization of the aneurysm can be confidently excluded. As a consequence of the low positive predictive value however, additional DSA may be necessary in case of incomplete occlusion seen on CEMRA. The results of this assessment employing CEMRA are not better than those published in the literature employing time-of-flight (TOF) MRA in this patient population.
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