Klinička primjena ultrazvučnog kontrastnog sredstva

master's thesis

• Title (english): Clinical application of ultrasound contrast agent
• Author: Lavinia Mehinović
• Mentor: Gordana Ivanac (mentor)
• Committee member: Boris Brkljačić (predsjednik povjerenstva)
• Committee member: Milan Radoš (član povjerenstva)
• Committee member: Gordana Ivanac (član povjerenstva)
• Granter: University of Zagreb; School of Medicine; (Department of Radiology); Zagreb
• Defense date and country: 2018-07-13, Croatia
• Scientific / art field, discipline and subdiscipline: BIOMEDICINE AND HEALTHCARE; Clinical Medical Sciences; Radiology

Abstract

Ultrazvučna kontrastna sredstva su tvari koje pojačavaju ehogenost (sposobnost odbijanja UZV valova) u tkivima ili organima u kojima se nalaze. U prikazima u B-modu struktura u kojoj se nalazi ultrazvučno kontrastno sredstvo biti će svjetlija, a sonogram (ultrazvučni prikaz) kontrastniji. Osnovna reflektivna čestica ultrazvučnog kontrastnog sredstva (mikromjehurića) sastoji se od plina oko kojeg je obloga (stabilizira mikromjehuriće sprečavajući izlazak plina i njegovo otapanje u okolnoj tekućini). Ultrazvučna kontrastna sredstva su primjenu našla prvenstveno u neinvazivnim prikazima srca (ehokardiografija), procjeni perfuzije tkiva, mikrovaskularnog protoka i volumena krvi te u prikazu karotidne arterije i neovaskularizaciji aterosklerotskog plaka (što je i meta za buduće sisteme ciljane primjene lijekova). FDA je za upotrebu u SAD-u odobrila dva preparata mikromjehurića: Optison (od 1997.) i Definity (od 2001.) za poboljšanje kvalitete ehokardiograma lijevog srca. U Europi su u upotrebi drugi preparati (npr. Echovist), za poboljšanje signala venskog bazena i desnog srca. Glavna primjena kontrastom pojačanog ultrazvuka u Europi (i Japanu) je u detekciji i karakterizaciji fokalnih lezija jetre, ali tu primjenu FDA još nije odobrila za SAD. Primjena ultrazvučnog kontrastnog sredstva u srčanim problemima te u fokalnim lezijama jetre je potvrđena i ustaljena u kliničkoj primjeni, ali kliničke studije su zadnjih godina pokazale da za njegovu primjenu mjesta ima i u drugim indikacijama, kao što su dijagnostika tumora bubrega, dojke, gušterače te u procjeni aterosklerotskih promjena krvnih žila.

Abstract (english)

Diagnostic ultrasound is a non-harmful imaging method used routinely in today’s medicine. It is based on the use of high-frequency sound and different density (more accurately, different impedance) of different types of tissue. Ultrasound waves are created by the transducer, sent into the patient’s body through different types of tissue, and then returned to the transducer as a reflected echo. Ultrasound waves are reflected at the surfaces between tissues of different density, the reflection being proportional to the difference in impedance. If the densities of two tissues are very different, then the sound is completely reflected, resulting in total acoustic shadowing (for example behind bones, calculi, and air). If there is no difference in a tissue or between tissues (for example in homogenous fluids such as blood, urine, ascites, pleural effusion, etc.) there is no echo (echo-free structures). Some tissues in the human body have very similar densities (impedances) and because of that can be very hard to differentiate. Here is where contrast-enhanced ultrasound comes in – the microbubbles (contrast agents) act as echo-enhancers. The ideal contrast agent should be non-toxic, injectable intravenously, capable of crossing the pulmonary capillary bed after a peripheral injection, and stable enough to achieve enhancement for the duration of the examination. The goal is to make contrast-enhanced ultrasound as reliable and precise as contrast CT or MRI, so that the patients who have some adverse reactions to those contrasts still have an effective imaging method available.

• Keywords: ultrazvuk; kontrast; mikromjehurići
• Keywords (english): ultrasound; microbubbles; contrast
• Language: croatian
• URN:NBN: urn:nbn:hr:105:083952
• Study programme: Title: Medicine; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: doktor/doktorica medicine (doktor/doktorica medicine)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2019-01-07 13:28:51