Delineation of brain AVMs on MR-Angiography for the purpose of stereotactic radiosurgery

Dennis R Buis, Frank J Lagerwaard, Clemens M F Dirven, Frederik Barkhof, Dirk L Knol, René van den Berg, Ben J Slotman, W Peter Vandertop

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

PURPOSE: To assess the dosimetric consequences of brain arteriovenous malformation (bAVM) delineation on magnetic resonance angiography (MRA) for the purpose of stereotactic radiosurgery.

METHODS AND MATERIALS: Three observers contoured a bAVM in 20 patients, using digital subtraction angiography (V(DSA)) and three-dimensional time-of-flight MRA (V(MRA)). Displacement between contours was calculated. Agreement and differences between observers and imaging modalities were assessed. A standardized treatment plan with dynamic conformal arcs was generated and dosimetric coverage of all contours and the volume of normal brain tissue within the high dose region was determined.

RESULTS: The generalized reliability coefficient was "fair" for target volume (0.79), but "poor" for displacement (0.35). V(MRA) was larger than V(DSA) (5.0 vs. 4.0 mL, p = 0.001). No difference in displacement was found (2.8 vs. 2.5 mm, p = 0.156). Dosimetric coverage of V(MRA) was 62.9% (95% CI, 56.9-68.8) when V(DSA) was used as planning target volume, and coverage of V(DSA) was 83.5% (95% CI, 78.1-88.8) when V(MRA) was used for planning (p < 0.001). The mean volume of normal brain within the 80% isodose was larger when the bAVM was delineated on MRA (0.7 vs. 1.0 mL (p = 0.02) for targets < or =3 mL and 3.7 vs. 7.0 mL (p = 0.01) for targets >3 mL).

CONCLUSIONS: Brain arteriovenous malformations delineated on MRA are larger and more randomly displaced. However, for bAVMs < or =3 mL, the difference in volume of normal brain tissue within the high-dose region does not seem to be clinically relevant. Therefore, MRA-images might be used as the sole imaging modality for the radiosurgical treatment of bAVMs < or =3 mL when the bAVM is located in a noneloquent position.

Original languageEnglish
Pages (from-to)308-16
Number of pages9
JournalInternational journal of radiation oncology, biology, physics
Volume67
Issue number1
DOIs
Publication statusPublished - 1 Jan 2007

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