Faculty Bibliography

OBJECTIVE: Arteriovenous malformations (AVMs) are difficult lesions to treat, partly because it is difficult to formulate a three-dimensional mental image of the nidus and its supplying arteries, draining veins, and arteries of passage. Our purpose is to develop personal computer software that allows better visualization of complex, three-dimensional, connected vascular anatomy for surgical planning. METHODS: Vessels are defined from magnetic resonance angiograms and are symbolically linked to form vascular trees. The nidus of the AVM is also defined by magnetic resonance angiography. These representations of the nidus and vasculature can be viewed together in a software program that allows the user to color-code groups of vessels or to selectively turn connected groups of vessels "off" to avoid obscuring the part of the image that the user wants to observe. Structures can be viewed from any angle. The vessels can also be shown intersecting any magnetic resonance angiogram slice or superimposed upon digital subtraction angiograms obtained from the same patient. RESULTS: We report results from two patients with AVMs in which our representations were compared with the findings during surgery. Our three-dimensional vascular trees correctly depicted the relationship of the nidus to feeding vessels in three dimensions. We show findings in an additional, unoperated patient for whom vessel trees were created from three-dimensional digital subtraction angiography data and compared with a volume rendering of the original data set. CONCLUSION: Computer-assisted, three-dimensional visualizations of complex vascular anatomy can be helpful in planning the surgical excision of AVMs. Software programs that produce these images can provide important information that is difficult to obtain by traditional techniques. This imaging method is also applicable to guidance of endovascular procedures and removal of complex tumors.

Enlargement of the cerebral lateral ventricles is observed in several neuropsychiatric disorders with origins in early brain development. Lateral ventricle size is also predictive of poor neurodevelopmental outcome in premature infants. Three-dimensional (3-D) ultrasound (US) offers an improved methodology for the study of lateral ventricle volume in neonates and infants. To assess the validity of ventricle volume measures obtained with 3-D US, we compared the volumes obtained by 3-D US with magnetic resonance imaging (MRI) in seven infants. Ventricle volumes were determined using a computer-assisted image analysis program, IRIS. There was excellent correlation between ventricle volumes obtained with 3-D US and those obtained with MRI (intraclass correlation coefficient 0.92, F = 23.28, p = 0.00027), indicating that 3-D US provides valid measures of overall lateral ventricle volume compared to the "gold standard" of MRI. 3-D US can provide an economical and practical means of studying lateral ventricle volume in neonates, a neurostructural marker of abnormal brain development.