Object: Cerebral arteriovenous malformations (AVMs) have a higher postresection recurrence rate in children than in adults. The authors' previous study demonstrated that a diffuse AVM (low compactness score) predicts postresection recurrence. The aims of this study were to evaluate the intra- and interrater reliability of the AVM compactness score.
Methods: Angiograms of 24 patients assigned a preoperative compactness score (scale of 1-3; 1 = most diffuse, 3 = most compact) in the authors' previous study were rerated by the same pediatric neuroradiologist 9 months later. A pediatric neurosurgeon, pediatric neuroradiology fellow, and interventional radiologist blinded to each other's ratings, the original ratings, and AVM recurrence also rated each AVM's compactness. Intrarater and interrater reliability were calculated using the κ statistic.
Results: Of the 24 AVMs, scores by the original neuroradiologist were 1 in 6 patients, 2 in 16 patients, and 3 in 2 patients. Intrarater reliability was 1.0. The κ statistic among the 4 raters was 0.69 (95% CI 0.44-0.89), which indicates substantial reliability. The interrater reliability between the neuroradiologist and neuroradiology fellow was moderate (κ = 0.59 [95%CI 0.20-0.89]) and was substantial between the neuroradiologist and neurosurgeon (κ = 0.74 [95% CI 0.41-1.0]). The neuroradiologist and interventional radiologist had perfect agreement (κ = 1.0).
Conclusions: Intrarater and interrater reliability of the AVM compactness score were excellent and substantial, respectively. These results demonstrate that the AVM compactness score is reproducible. However, the neuroradiologist and interventional radiologist had perfect agreement, which indicates that the compactness score is applied most accurately by those with extensive angiography experience.