자기공명혈관촬영술을 이용한 분지형 경동맥 Phantom 상 혈류의 표현성에 대한 실험 연구

Abstract

Purpose : A common finding of carotid artery on magnetic resonance angiograms(MRAs) is a signal dropout along the posterior wall of carotid bulb due to reverse flow. The purpose of this study is to evaluate variable flow patterns on bifurcated carotid arterial phantoms using steady-state flow. Materials and Methods : We designed phantoms of a bifurcated carotid artery with acrylic materials. Flow patterns were evaluated with axial and coronal imaging of MRA(2D-TOF, 3D-TOF), color Doppler imaging, and computational fluid dynamics (CFD), within the phantoms constructed of an automated closed-type circulatiory system filled with 4% sugar solution. These findings were compared with findings obtained from normal volunteers. Results : Axial 3D-TOF MRA images exhibited colser resemblance to the contour of the inner wall of phantoms when compared to coronal 2D-TOF MRA imaging. However,2D-TOF MRA showed good contrast difference of signal intensities between forward flow area and reverse flow area. Dark zones with reduced signal intensities due to reversed flow were separated from the outer wall of the internal and external carotid arteries by a thin layer of forward flow along the wall on the source slice image of MRA. The general hemodynamics of the phantoms on MRA were identical to hemodynamics on color Doppler imaging and CFD. The results obtained with the phantoms matched the findings on normal volunteers. Conclusion : Although representations of bifurcated carotid arterial phantoms on axial 3D-TOF MRA were excellent if ideally desinged, the zone of reversed flow could be a significant factor in creating distorted image when the zone of reversed flow contacted directly with curved or deformed arterial wall.