Table 2.
Selection of imageable embolic microsphere systems described in the literature.
| Imaging modality | Embolic matrix | Imaging component | Method of inclusion | Comments | Study (year) | Ref. |
|---|---|---|---|---|---|---|
| X-ray | PHEMA | Iodine (triiodobenzyl groups) | Covalent coupling | 25-30 wt% loading | Horak et al. (1987) | 94 |
| X-ray | PMMA (hydrolyzed) | Barium sulfate | Precipitation | 70 wt% loading achieved | Thanoo and Jayakrishnan (1989) | 95 |
| X-ray | PHEMA | Iodine (iothalamic/iopanoic acid) | Covalent esterification | 30 wt% loading achieved | Jayakrishnan et al. (1990) | 96 |
| X-ray | PHEMA | Barium sulfate | Entrapment | 40-50 wt% loading achieved | Thanoo and Jayakrishnan (1990) | 97 |
| X-ray | Silicone | Tantalum powder | Entrapment | Needed surface modn. | Thanoo and Jayakrishnan (1991) | 98 |
| X-ray | PHEMA copolymer | Iodine (triiodobenzyl monomer) | Copolymerization | 27 wt% achieved | Horak et al. (1997) | 99 |
| X-ray | PHEMA/PVP copolymers | Iodine (monoiodobenzyl monomer) | Copolymerization | 20 wt% achieved | van Hooy-Corstjens et al. (2008) | 100 |
| CT | Alginate | MoS2 nanosheets | Entrapment | 12% loading | Fu et al. (2017) | 101 |
| CT | PLGA | Iodine (2,3,5-triiodobenzoic acid (TIBA)) | Entrapment | 23.15 wt % Iodine loading/Sorafenib loading demonstrated | Choi et al. (2017) | 102 |
| CT | Polystyrene | Tantalum oxide | Entrapment | 9.4 wt% tantalum oxide loading | Morrison et al. (2015) | 103 |
| CT | PLAU | Iodine (4,4′-isopropylidinedi-(2,6-diiodophenol) (IBPA)) | Copolymerization | 14.48 wt% Iodine loading | Sang et al. (2017) | 72 |
| CT | PVAL | Iodine (4-iodobenzyl or 2,3,5-triiodobenzyl groups) | Copolymerization | 40-70 wt % Iodine loading | Agusti et al. (2015) | 104 |
| MR | Trisacryl (Embosphere) | Iron oxide (SPIO) | Entrapment | Detectable by common echo sequences | Namur et al. (2007) | 105 |
| MR | Trisacryl (Embosphere) | Iron oxide (SPIO) | Entrapment | 100% detectable | Lee et al. (2008) | 106 |
| MR | PVA | Gadolinium III Chelates | Covalent coupling | 45.5 μg Gd(III)/mg PVA | Cilliers et al. (2008) | 107 |
| MR | Chitosan | Iron oxide (SPIO) | Entrapment | 1.0 mM SPIO loading | Chung et al. (2012) | 108 |
| MR | Alginate | Prohance® and Holmium ions |
Complexation/entrapment | T1 MRI & T2 MRI 0~1.35wt% Ho3+ loading | Van et al. (2015) | 109 |
| MR | Alginate | Iron oxide (SPIO) | Entrapment | 0.06 ~ 6.0 mg/mL SPIO loading | Wang et al. (2017) | 67 |
| MR/gamma | Alginate | Holmium | Complexation | 1.3 wt% Ho loading | Zielhuis et al. (2007) | 110 |
| CBCT/MR | Alginate | Holmium and iodine (Lipiodol) | Complexation/entrapment | 0.38% Ho loading | Oerlmans et al. (2015) | 111 |
| DSA/CT | Alginate | Barium sulfate | Complexation | Microfluidic method | Wang et al. (2015) Du et al. (2018) |
88, 112 |
| DSA/CT | Alginate | Tantalum nanoparticles | Entrapment | 10 w/v% Ta loading | Zeng et al. (2018) | 93 |
| DSA/CT/MRI | P(MAOETIB-GMA) | Iodine/ Iron oxide (SPIO) | Copolymerization/ Precipitation | diameter 40-200 µm | Bartling et al. (2011) | 113 |
| Radiography/MR/CT | PMAA (Embozene) | Barium sulfate/iodine/iron oxide | Precipitation/entrapment | Three different loading densities | Stampfl et al. (2012) | 114 |
| Fluoro/μCT/CT | PVA-AMPS (DC/LC bead) | Iodine (Lipiodol) | Entrapment | Dose-dependent imaging | Sharma et al. (2010) | 115 |
| Fluoro/μCT/CT | PVA-AMPS (DC/LC bead) | Iodine (Lipiodol) | Entrapment | Correlation with drug | Dreher et al. (2012) | 116 |
| Fluoro/μCT/MDCT/CBCT | PVA-AMPS (DC/LC bead) | Iodine (Lipiodol) | Entrapment | Different imaging modes | Tacher et al. (2016) | 117 |
| μCT/CT | PVA-AMPS (DC/LC bead) | Iodine (triiodobenzyl groups) | Covalent attachment | Drug loading demonstrated | Negussie et al. (2015) | 118 |
| Fluoro/μCT/CT | PVA-AMPS (DC/LC bead) | Iodine (triiodobenzyl groups) | Covalent attachment | IR imaging reading study | Duran et al. (2016) | 119 |
| US/MR/PA | PLGA | SPIO/Perfluorohexane | Entrapment | double-emulsion process | You et al. (2016) | 120 |
Note: CBCT: Cone-beam computed tomography; CT: Computed tomography; DSA: Digital subtraction angiography; Ho: Holmium; modn: Modification; MDCT: Multidetector computed tomography; MR: Magnetic resonance; PHEMA: Poly(2-hydroxyethyl methacrylate); PLAU: Poly(lactic acid)-polyurethane; PLGA: poly(lactic-co-glycolic acid); P(MAOETIB-GMA): homopolymerization of 2-methacryloy-loxyethyl (2,3,5-triiodobenzoate) (MAOETIB) with glycidyl methacrylate (GMA). PMMA: Poly(methylmethacrylate); PVP: Poly(N-vinyl-2-Pyrrolidone); PMAA: Poly(methylacrylic acid); PVA-AMPS: Poly(vinyl alcohol-co-2-acrylamido-2-methylpropane sulfonate); SPIO: Super paramagnetic iron oxide; US: Ultrasound; PA: Photoacoustic. Expanding based on the work of Lewis et al. 38