Multi-Atlas Segmentation of Biomedical Images: A Survey

Abstract Multi-atlas segmentation (MAS), first introduced and popularized by the pioneering work of Rohlfing

Healing Response to Coronary Stenting In Acute Coronary Syndrome – Early Anatomical and Functional Healing Assessed by Optical Coherence Tomography and Flow Reserve

Drug-eluting stents are associated with delayed vascular healing. Anatomical and functional healing of coronary arteries after balloon angioplasty with stenting was investigated in patients presenting with acute coronary syndrome. Bioactive stents, sirolimus-, zotarolimus-, and everolimus-eluting stents were compared in two ran-omized trials with optical coherence tomography and coronary flow reserve measurement at 2- or 3-month follow-up after stenting. Coronary flow reserve measurements were obtained by invasive thermodilution and transthoracic echocardiography. Variability of optical coherence tomography data was assessed between observers and sampling intervals. Uncovered stent struts and impaired coronary flow reserve values were detected in all stent groups, and a link between anatomical and functional healing was discovered. Bioactive stents showed earlier and more comprehensive neointimal coverage, which happened at the expense of luminal narrowing. Strut malapposition occurred frequently despite post-dilatation. Measurement of coronary flow reserve by transthoracic echocardiography was feasible after stenting in the left anterior descending artery of non-diabetic patients, and agreement with the invasive method was good. The results confirm that noninvasive measurement of coronary flow reserve by echocardiography can be considered for follow-up after stenting. The sampling interval of optical coherence tomography cross-sections had a significant effect on the observed percentage of uncovered and malapposed struts. The shorter sampling interval of 0.6 mm can be used to reduce variability and overestimation of strut level data.Sepelvaltimostenttien paranemisvaste sepelvaltimotautikohtauksen hoidossa – varhainen anatominen ja toiminnallinen paraneminen valokerroskuvauksella ja virtausreservillä tarkasteltuna Lääkestentteihin liittyy viivästynyttä verisuonen seinämän paranemista. Sepelvaltimoiden anatomista ja toiminnallista paranemista pallolaajennuksen jälkeen selvitettiin akuutin sepelvaltimotautikohtauksen saaneilla potilailla. Bioaktiivisia sekä sirolimuusia, everolimuusia ja tsotarolimuusia vapauttavia stenttejä vertailtiin kahdessa satunnaistetussa tutkimuksessa valokerroskuvantamisella ja virtausreservimittauksella 2 tai 3 kuukauden kuluttua stenttauksesta. Virtausreservimittaukset suoritettiin sekä kajoavalla termodiluutiomenetelmällä että kajoamattomalla kaikututkimuksella rintakehän päältä. Valokerroskuvantamismittausten hajontaa vertailtiin havainnoijien ja otantatiheyksien välillä. Peittymättömiä stentin osia ja heikentyneitä virtausreserviarvoja havaittiin kaikissa stenttiryhmissä ja anatomisen ja toiminnallisen paranemisen välillä havaittiin yhteys. Bioaktiiviset stentit osoittautuivat peittyneen endoteelilla aikaisemmin ja kattavammin, mikä puolestaan johti suonen kaventumiseen. Huono kontakti suonen seinämään oli yleistä jälkilaajennuksesta riippumatta. Kaikututkimus mahdollisti virtausreservin mittauksen kajoamattomasti vasemman laskevan haaran stenttauksen jälkitilassa diabetesta sairastamattomilla ja mittausarvot korreloivat hyvin kajoavalla menetelmällä mitattujen arvojen kanssa. Tulokset vahvistavat, että kajoamatonta virtausreservin mittausta kaikututkimuksella voidaan hyödyntää stenttauksen jälkeisessä seurannassa. Valokerroskuvauksen otantatiheys vaikutti merkitsevästi stenttien havaittuun peittymättömyyden ja malapposition osuuteen. Tiheämmällä 0,6 mm otantavälillä voidaan vähentää hajontaa ja peittymättömyyden yliarviointia.Siirretty Doriast

Depth-Resolved Assessment of Atherosclerosis by Intravascular Photoacoustic-Ultrasound Imaging

Coronary heart disease is the leading cause of death in the United States and the incidence is projected to increase by 18% by 2030. Yet, there remains a pressing clinical need for tools to detect vulnerable atherosclerotic plaques that can rupture and lead to major adverse cardiac events. Plaques that are considered most vulnerable for rupture are thin-capped fibroatheromas, which are grossly defined by hallmarks of a thin fibrous cap, a large lipid-rich necrotic core, inflammatory infiltrate, and positive remodeling. These plaques are often structurally non-obstructive to moderately obstructive, thus asymptomatic and clinically unidentifiable with routine angiography and stress testing. Rather, their vulnerability is a product of their chemical composition. We have developed a dual-mode intravascular catheter which is capable of producing co-registered cross-sectional images of arterial wall morphology and lipid content, via ultrasound and photoacoustic modes, respectively. Validation of this capability will rely on interrogation of atherosclerotic coronary arteries from humans and peripheral arteries from swine, with comparison to gold-standard histopathology and competing technologies. Here, we present ex vivo validation of a novel intravascular photoacoustic-ultrasound (IVPA-US) imaging catheter and the first systematic in vivo IVPA-US imaging study in a preclinical swine model with native disease, necessary benchmarks before proceeding with translation to clinic. We aim to ultimately demonstrate predictive utility to detect plaques that are vulnerable to rupture and trigger adverse cardiac events. In addition, this will be instrumental in elucidating the mechanism of plaque rupture, the development of preventive and therapeutic interventions, and reducing coronary heart disease-related mortality