View clinical trials related to Tomography, Optical Coherence.
Filter by:In calcified lesions, optimal stent placement and expansion may prove to be challenging. Lesion preparation is necessary to facilitate optimal stenting in calcified lesions, for which orbital atherectomy can used. Therefore the aim of this study is to: 1. Show that orbital atherectomy effectuates optimal stent expansion 2. Investigate the mechanics of lesion preparation when using orbital atherectomy Patients presenting with a significant and severely calcified lesion in need of orbital atherectomy will undergo optical coherence tomography guided orbital atherectomy and stent placement.
Kidney biopsy play a key role for the investigation of either acute kidney injury or chronic kidney disease. Despite possible complications due to the invasive nature of the biopsy, such procedure is still essential in a number of clinical situations to improve the diagnosis specificity of kidney disease, better inform about its prognosis and guide the management of a future treatment. Pursuing the idea to improve both performance and rapidity associated with the histopathological analysis of kidney biopsy, with a possible recourse to artificial intelligence-based renal pathology, the present study intends to assess the impact of direct histopathological examination of kidney biopsy with dynamic full-field optical coherence tomography in routine practices for the diagnosis of either acute kidney injury or chronic kidney disease.
Giant cell arteritis (GCA) is a type of large vessel granulomatous vasculitis responsible for the inflammation of the aorta and the branches of the external carotid, notably temporal arteries. The diagnosis of GCA relies upon the identification of vasculitis following histopathological analysis of temporal artery biopsy (TAB) showing mononuclear cells infiltration, fragmentation of the internal elastic lamina as well as significant intimal hyperplasia. Apart from its lack of sensitivity, one of the weaknesses of TAB is the delay in obtaining the result due to the time required to prepare the sample for histological analysis. Pursuing the idea to improve TAB performances, our group recently demonstrated the use of full-field optical coherence tomography (FF-OCT) to visualize structural changes associated with the inflammatory processes of GCA. The present work suggests a further use of dynamic FF-OCT on TAB for a direct visualization of the mononuclear cells infiltration to ensure rapid on-site diagnosis of GCA.
This trial is designed to associate angiography-based fractional flow reserve (3D-angio-based FFR) values with optical coherence tomography findings in pre- and post-percutaneous coronary intervention in patients with non-ST segment elevation acute coronary syndromes.
Prospective, multicentre, non-randomized, investigator-initiated study aiming to assess the safety and efficacy of the Fantom Encore sirolimus-eluting bioresorbable scaffold (BRS).
The study will compare two invasive methods (FFR -fractional flow reserve and iFR—instantaneous wave free ratio) for assessment of hemodynamic impact of coronary stenosis on myocardial perfusion. There is a very good correlation between these methods for the assessment of hemodynamic significance in a broad spectrum of lesions. However, this correlation decreases significantly near the cut off points for each method. The investigators will try to find possible explanations for these differences by detailed morphology assessment of coronary stenosis using optical coherence tomography (OCT), analysis of gene polymorphisms that play a role in vasodilatation, and by shear stress analysis. The head-to-head comparison between FFR and iFR is not simple, because there is no "gold standard" for assessment of hemodynamic significance. Studies comparing these methods have used hyperemic stenosis resistance (HSR). For this kind of measurement it is necessary to measure the speed of blood flow. This is usually done by a Doppler analysis of flow. Unfortunately, the Doppler signal can yield many artificial or erroneous indicators, and obtaining a good quality signal is frequently time-consuming. These are the reasons that HSR has not been used in routine practice. The investigators have developed a new console and software that can provide real time analysis of the Doppler signal. It allows us to easily measure HSR, and to differentiate between the FFR and iFR measures through intrabeat analysis of microvascular resistance (lowest microvascular resistance is an essential condition for proper pressure measurement). Using this tool, it is possible to automatically identify the point of lowest microvascular resistance during each cardiac beat. The pressure gradient can then be measured at that point. This approach can eliminate almost all uncertainties in assessment of the pressure gradient produced by coronary stenosis. This tool can potentially improve the existing methods used to precisely reveal a significant stenosis. This should increase the number of hemodynamic guided procedures.