Definition of the ostium (neck) of an aneurysm revealed by intravascular sonography: an experimental study in canines.

BACKGROUND AND PURPOSE The major factor influencing the effectiveness of Guglielmi detachable coils (GDCs) in the treatment of saccular aneurysms is the size of the aneurysm's ostium (neck). Current imaging techniques often do not allow accurate assessment of aneurysm neck morphology. The primary purpose of this study was to determine the feasibility of using intravascular sonography to provide this information. METHODS Lateral and bifurcation aneurysms were created in each of six adult mongrel dogs by using a well-established surgical technique. Aneurysms were evaluated with digital subtraction angiography and intravascular sonography before (n = 12) and after (n = 6) treatment with GDCs. Angiography was performed using standard techniques. Sonography was performed using both a commercially available 2.6F 40-MHz catheter and a preproduction 0.014-inch 40-MHz imaging core wire housed in a Tracker catheter. Angiograms and sonograms were reviewed independently by two observers to assess the clarity and accuracy with which they depicted the size of each aneurysm's ostium. Posttreatment intravascular sonograms were evaluated for the extent to which they depicted the completeness of aneurysm obliteration. Two-dimensional reformatted images were made of the intravascular sonographic pullback sequences. RESULTS In all instances, intravascular sonography provided clear definition of the aneurysm's neck (ostium) morphology as well as its relationship to the parent artery and adjacent branches, especially when 2D reformatted images were obtained. The position of coils in aneurysms was also clearly defined. CONCLUSION Intravascular sonography is a novel technique for viewing the ostium (neck) of an aneurysm. It provides information not available with current angiographic methods.