Natural History of Brain Arteriovenous Malformations in Hereditary Hemorrhagic Telangiectasia: A Longitudinal Neuroimaging Study

Purpose: The natural history of brain arteriovenous malformations (bAVMs) in Hereditary Hemorrhagic Telangiectasia (HHT) remains poorly understood and it has been suggested that they may have a benign course different from sporadic bAVMs. Here, we present a single-center longitudinal study evaluating the growth of bAVMs over time as assessed by serial MRIs. Methods: We performed a retrospective analysis of 44 patients with suspected bAVMs followed at an HHT Center of Excellence from 2014 to 2024. We excluded patients that did not have serial MRIs and/or poor-quality MRIs, and patients without radiographic bAVMs. Primary outcome was growth of bAVM as measured by largest dimension on T1 post-contrasted weighted sequences of serial MRIs. Secondary outcome was hemorrhage from bAVM rupture. Results: Twelve patients (3 male, 9 female) met our criteria. Average age at first MRI was 39.9 years (range 6 -65 years). Ten patients had micro-bAVMs and 3/10 of these patients had multiple micro-bAVMs. None of the micro-bAVMs showed any growth on serial MRIs. The other two patients in our study had bAVMs with niduses >1 cm and showed an average rate of growth of 1.61 mm/year. Ultimately, none of our patients had rupture of bAVMs over an average radiographic follow-up of 4.15 years and a total of 49.78 patient years. Conclusion: Our study suggests that bAVMs in HHT patients may have a benign natural history. We found no hemorrhages and noted minimal growth of bAVMs on serial MRIs. Our results suggest HHT patients with bAVMs may not warrant frequent surveillance imaging.