Observer agreement in the assessment of minor and major cerebral aneurysm recurrence.

We studied the use of minor and major recurrence classifications with regard to observer variability, which directly affects validity of these terms as outcome measures. Recurrences at the time of a three to six month follow-up angiogram were assessed independently by two experienced observers in 83 cases. Intra- and interobserver concordance is approximately 90% for assessment of minor and major recurrence.