High resolution MR imaging and localization of laser-induced thermal injury in the vascular wall

With the increasing use of lasers in surgical procedures, there is need for a noninvasive imaging modality to monitor laser-tissue interactions. MRI can be used readily for imaging human anatomy and holds the potential to map laser-induced thermal injury. This study investigates high resolution T1-weighted MR imaging of human aorta samples (in vitro) that have been damaged thermally using an argon ion laser and the corresponding histology. High resolution T1-weighted MR images (voxel size, .156 x .156 x .700 mm) clearly detected residual thermal injury as areas of bright signal intensity. Effective localization of thermal injury was achieved by subtraction of preinjury and postinjury slices with pseudocoloring of positive and negative differences. The results may serve as a basis from which to guide future in vivo studies.