<title>Evaluation of multidirectional fluorescence-sensing laser catheter for the development of an intelligent laser angioplasty system</title>

Abstract

. AbstructThe differential diagnostic capacity of a multi-directional sensing catheter with intraluminal objects was evaluated by fluorescence analysis following administration of a photosensitizer. The measurement catheter is 1.7 mm in diameter and is constructed with cross-sectional arrangement of 6 sensor bundle units and a centered guide wire lumen. Fluorescence was analyzed by polychrometer and amplified CCD camera with an image intensifier. The excitation light was 405nm wavelength obtained from an Xe-Hg lamp using a band pass filter. In vivo and in vitro fluorescence analysis of normal and atherosclerotic rabbit aorta was performed following intravenous administration of 5 mg/kg Hematoporphyrin Derivatives (HpD) 24 hours before. The diagnostic algorithm was based on the spectrum profile, a peak at 405nm and Plaque Index (PI=[F1630-(O.76F1600-i-O.24F1725)] /F1600) was identified for the fluorescence spectrum detected by each one of sensing units. Blood and fresh thrombus showed a flat profile without a 405nm peak (sens.=83.3%, spec.=100%). The normal arterial wall was PI O.15 with a 405nm peak. Intima of less than 200p.m was O.15<PI<z2.O (sens.=92%, spec.=97%) and atherosclerosis (more than 200p.m intimal thickness) was 2.O PI (sens.=98%, spec.=lOO%). The multi-directional sensing catheter detected fluorescence spectra independently in real time. In vivo measurement of this catheter showed, relative to the tip of catheter, in which direction there was blood, normal intima, slight intimal thickness, which should not be treated by laser, or areas of atherosclerosis, which can be treated by laser. 0-8194-1

Optical spectroscopy for in vivo medical diagnosis—a review of the state of the art and future perspectives

“…There have been many examples of the use of fluorescent spectroscopy to discriminate between healthy and diseased tissues ex vivo published since the earliest report in the 1940s [98]. There have also been many examples of fluorescent point-based spectroscopy for diagnostic discrimination of healthy and diseased tissues in many parts of the anatomy, both in developmental animal models and in human medical trials, including the alimentary tract [44,, heart or major arteries [131][132][133][134][135][136][137][138][139][140][141], bladder [142][143][144][145][146][147][148][149], brain [45-48, 143, 150-175], breast [176], cervix [177][178][179][180][181][182][183][184][185][186][187][188][189][190][191][192][193][194], endocrine system [195][196][197][198]…”

In vitro study of a radiofrequency guidewire aimed at recanalization of totally occluded peripheral arteries

“…Previous studies were aimed at performing a reliable feedback system for angioplasty. Most of them were based on luminescence analysis using a combination of a therapeutic laser with a second diagnostic laser exciting the tissue [26] or complex multifiber catheters irradiating the tissue and detecting the fluorescence signal continuously [27]. During radiofrequency ablation one can measure the electrosur- gical parameters, namely the impedance or current, and estimate the parameters of ablation such as the depth of penetration.…”