Table 1.
Dual-mode CAs, set-up parameters and operating conditions for in vitro MRI and UI tests according to different studies. n.a., not available. MBN-into, MBs with nanoparticles entrapped into the shell; MBN-on, MBs with nanoparticles anchored to the shell; END-into, encapsulated nanodroplets filled with fluorescent dyes and SPIONs (transformed into nanobubbles and MBs by ultrasound irradiation); PLA, poly(dl-lactide); PVA, poly(vinyl alcohol); PBCA, poly(butyl cyanoacrylate); PLGA, poly(lactic-co-glycolic acid); PEG, poly(ethylene glycol).
| paper | CA type | mean diameter (µm) | shell | UI: frequency and peak pressure | MRI: magnetic flux density | MB concentration (MBs/ml) | nanoparticle density (µg/ml) | notes |
|---|---|---|---|---|---|---|---|---|
| Yang et al. [4] | MBN-into | 3.98 | 2 layers: PLA and PVA | 3.5 MHz | 7.0 T | 7 × 108 | 5.73–180.23 | UI: standard B-mode imaging technique |
| 187 kPa | MRI: T2-weighted fast spin-echo. | |||||||
| Park et al. [5] | MBN-on | 5 | lysozyme-alginate mixture | n.a. | 3.0 T | 104 | UI: n.a. | UI: comparison of MBN-on loaded with different nanoparticles (SPIONs, gold, or silica) |
| n.a. | MRI: 0.47–4.7a | MRI: T2*-weighted fast field-echo; comparison of MBs with different SPION densities | ||||||
| Liu et al. [6] | MBN-into | 2.3 | PBCA | 25 MHz | 3.0 T | UI: 4 × 104 | UI: 0.17–0.62 × 10−3a | UI: before and after ultrasound-induced destruction |
| n.a. | MRI: approximately 109 | MRI: 20–80a | MRI: T1- and T2-weighted multi-spin-echo before and after ultrasound-induced destruction | |||||
| He et al. [8] | MBN-on | n.a. | PVA | 3.5 MHz | 7.0 T | UI: 1.8 × 108 | 91.73 | UI: standard B-mode imaging technique |
| MBN-into | n.a. | MRI: 0.18–1.8 × 108 | MRI: T2-weighted multi-slice multi-echo | |||||
| Cheng et al. [9] | END-into | 0.385 | 2 layers: PLGA-PEG-PLGA and PVA | 3.5 MHz | 3.0 T | n.a. | UI: n.a. | UI: comparison between proposed nanodroplets and commercial ultrasound CAs |
| 243 kPa | MRI: 2–20a | MRI: T2-weighted spin-echo | ||||||
| This paper | MBN-on | 3.8 | PVA | 4.5 MHz | 0.25 T | 106 | 2–5b | UI: comparison of contrast-enhanced techniques |
| MBN-into | 230–320 kPa | MRI: T2*-weighted gradient-echo |
aApproximate values computed from set-up parameters.
bSPION percentage of 15–38% with respect to the mass of a single MB.