Changes in AVM angio-architecture and hemodynamics after stereotactic radiosurgery assessed by dynamic MRA and phase
Lydia Schuster1, E Schenk, F Giesel
1Department of Radiology, German Cancer Research Center, Im Neuenheimer Feld 280, 69120, Heidelberg, Germany. l.schuster@dkfz-heidelberg.de
Objectives:
Assessment of changes in the hemodynamics of Arteriovenous malformations (AVM) induced by radiosurgery by MR Phase contrast (PC) measurements of the internal carotid arteries (ICA).
Methods:
65 patients shortly after or before stereotactic radiosurgery underwent MRI including morphological series, MR-Angiography (Time-of-flight, dynamic MRA) and bilateral ECG triggered MR phase contrast (PC) measurements of the ICA. Follow-up was performed in 34 patients. The observation period was up to 4 years.
Results:
Over all subjects, a significant relationship between mean arterial blood flow in the ICA on the side of the lesion and AVM volume was revealed (p = 0,0002). In large (>10 ccm) and medium-sized AVMs, (>3, 5 ≤ 10 ccm) the blood flow was significantly increased on the side of the AVM (p = 0,0004; p = 0,047), whereas in lesions <3, 5 ccm, no significant rise of the mean blood flow was detectable. At follow-up, the mean blood flow in the ipsilateral artery was not increased anymore compared to the contralateral ICA (p = 0,11). These changes correlated with a significant reduction of the average AVM volume (p = 0, 0026).
Conclusions:
The AVM angioarchitecture has significant impact on the blood flow in feeding arteries. A significant reduction of the shunt volume by successful radiotherapy leads to normalization of the hemodynamics.
