Can the probability for obliteration after radiosurgery for arteriovenous malformations be accurately predicted?

Purpose: To investigate how accurate different models predict the probabili ty for obliteration following radiosurgery for an arteriovenous malformatio n (AVM), Methods and Materials: The probability for obliteration was calculated for all 838 AVMs with a known treatment outcome and treated at the Karolinska H ospital with Gamma Knife surgery 1970-1993, Four different models were used for the calculation, resulting in four different values of the probability for obliteration. The calculated prediction values were added for each mod el, and the total number of predicted obliteration compared to that observe d in the whole patient material as well as in different subgroups. Results: Three of the four models predicted the total number of obliteratio ns accurately. In two of those three models, the accuracy of the prediction was dependent on AVM volume and treatment dose. In one model only, the pre diction was accurate and independent of all investigated parameters. Conclusions: The probability for obliteration was accurately predicted by o ne of the models analyzed. In this model, the probability for obliteration was related to the dose to the AVM periphery only. The AVM volume had no in dependent impact on the probability for obliteration. There was a trend tha t AVMs with a central location had a better obliteration rate than predicte d. (C) 1999 Elsevier Science Inc.