The Application Of Preoperative Imaging Technology In Perforator Flap Design And The Research Of A New Nanoprobe Fluorescent Contrast Agent

The application of flap technique plays an extremely important role in plastic and reconstructive surgery.Since 1989,the perforator flap technique has emerged as the new frontiers in modern reconstructive surgery.However,the significant anatomical variability of perforator vessels limited the application of the perforator flaps and its final outcomes of the repair.As a result,the anatomy of the perforator and the choice of the optimal perforators have turned into the a hot area of research.The researches mainly focus on the following two aspects.（1）The localization of perforators:where they are located,vessel caliber,how they run in subcutaneous tissue and muscle.（2）The size of the flap they supply.To solve the urgent issues mentioned above,based on the former researches,we performed following experiments.Section One:The application of pre-operation imaging technology in perforator flap design.This section focused on the localization of perforator vessels.Based on the previous study of perforator localization imaging technology by computed tomography angiography（CTA）and color Doppler ultrasound（CDU）,this research further improve the accuracy of both perforator location technology and facilitate the design of perforator flaps.1.This research explored the optimal CT scanning parameters and set up the localization and imaging measuring system on the CTA imaging technology.Furthermore,two innovative techniques were put forward including a new contrast agent tracing technique which made the imagings of perforators clearer,and a new coordinate model technique which facilitated the perforators localization and reduced the measurement error of the vessels.2.This study combined the color Doppler ultrasound with the contrast agent to increased the perforator imaging signal and improve its sensitivity to the tiny perforator vessels.3.This investigation compared the application of color Doppler ultrasound and computed tomographic angiography in preoperative planning of lower extremity perforator flaps,including the recognition rate and accuracy of identification of the dominant perforator.The time and cost of the two techniques are also concerned.This research described that the two techniques have different advantage and disadvantage and pointed out for the first time that the respective optimal regions of human body for each technique which will guide the clinical practice of locating perforators.Section two:The research of an innovative nanoprobe fluorescent contrast agent.The evaluation of the perforator flap perfusion requires a technology and contrast agent that is capable of demonstrating the actual perfusion range of the flap in real time with high-resolution images.Compared to current imaging contrast agent indocyanine green（ICG）in clinical practice,quantum dots（QDs）nanoprobe is more attractive due to their excellent optical properties and potential of functionalized modifications and application.1.In this part we have developed a micromave-assisted and direct water-phase synthesized PbS quantum dots（PbS QDs）and Ag₂S quantum dots（Ag₂S QDs）which are water-soluble and have high quantum yield and good biocompatibility.Compared with ICG whose emission peak is in 780-850nm,the emission peak of the water-soluble PbS QDs is located at the second infrared window（NIR-Ⅱ,900-1300nm）which has the greater penetration of tissue and lower background autofluorescence.It has a greater biomedicine application prospect.2.We prepared the animal model of the deep circumflex iliac artery perforator flap and the superficial epigastric artery perforator flap in SD mice.We compared the two kinds of models and decided to choose the former for the following experiments of flap fluorescence imaging.3.We injected PbS QD as fluorescent contrast intravenously to study the blood supply range of the flap model.ICG was injected in the same manner in the control group.The accuracy of the two contrast mediums was compared.The results showed that the PbS QDs were more accurate in demonstrating the perfusion range and its images had higher resolution.PbS QDs were not only able to reflect the perfusion range of the flaps objectively,but also had a good chance of predicting the existence of‘potentially damaged’tissue in the distal part the flaps.We believe that PbS QDs have great potential in clinical application.