Effect of perfluorocarbon composition on activation of phase-changing ultrasound contrast agents.
Med Phys
; 49(4): 2212-2219, 2022 Apr.
Article
em En
| MEDLINE
| ID: mdl-35195908
ABSTRACT
BACKGROUND:
While microbubble contrast agents (MCAs) are commonly used in ultrasound (US), they are inherently limited to vascular targets due to their size. Alternatively, phase-changing nanodroplet contrast agents (PNCAs) can be delivered as nanoscale agents (i.e., small enough to extravasate), but when exposed to a US field of sufficient mechanical index (MI), they convert to MCAs, which can be visualized with high contrast using nonlinear US.PURPOSE:
To investigate the effect of perfluorocarbon (PFC) core composition and presence of cholesterol in particle coatings on stability and image contrast generated from acoustic activation of PNCAs using high-frequency US suitable for clinical imaging.METHODS:
PNCAs with varied core compositions (i.e., mixtures of perfluoropentane [C5] and/or perfluorohexane [C6]) and two coating formulations (i.e., with and without cholesterol) were characterized and investigated for thermal/temporal stability and postactivation, nonlinear US contrast in phantom and in vivo environments. Through hydrophone measurements and nonlinear numerical modeling, MI was estimated for pulse sequences used for PNCA activation.RESULTS:
All PNCA compositions were characterized to have similar diameters (249-267 nm) and polydispersity (0.151-0.185) following fabrication. While PNCAs with majority C5 core composition showed higher levels of spontaneous signal (i.e., not due to US activation) in phantoms than C6-majority PNCAs, all compositions were stable during imaging experiments. When activating PNCAs with a 12.3-MHz US pulse (MI = 1.1), C6-core particles with cholesterol-free coatings (i.e., CF-C6-100 particles) generated a median contrast of 3.1, which was significantly higher (p < 0.001) than other formulations. Further, CF-C6-100 particles were activated in a murine model, generating US contrast ≥ $ \ge $ 3.4.CONCLUSION:
C6-core PNCAs can provide high-contrast US imaging with minimal nonspecific activation in phantom and in vivo environments.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Meios de Contraste
/
Fluorocarbonos
Tipo de estudo:
Diagnostic_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2022
Tipo de documento:
Article