Distribution and Detection of Radiopaque Beads after Hepatic Transarterial Embolization in Swine: Cone-Beam CT versus MicroCT

Abstract

The full ROB distribution was more extensive than was apparent on cone-beam CT. Quantitative measures of embolic distribution demonstrated significantly better correlation with microCT with decreasing kVp. Similarly, qualitative analysis of MIPs showed improved visualization of beads with decreasing kVp. These findings demonstrate the clinical value of 80 kVp and 100 kVp protocols in the imaging of radiopaque embolizations compared with 120 kVp. However, considerations on X-ray penetration and dose may favor use of 100 kVp imaging over 80 kVp.

Mapping Drug Dose Distribution on CT Images Following Transarterial Chemoembolization with Radiopaque Drug-Eluting Beads in a Rabbit Tumor Model

“…As such, future studies may benefit from a tumor model (eg, hepatocellular carcinoma in the woodchuck model) that more closely recapitulates the highly vascular nature of hepatocellular carcinoma in humans. Finally, consistent with previous findings, very low bead densities were inconspicuous on CT images despite their visibility on micro-CT images (35). Thus, a model with nonzero intercept was used to account for low concentrations of DOX potentially associated with bead densities below the CT detection threshold.…”

Bench-To-Clinic Development of Imageable Drug-Eluting Embolization Beads: Finding the Balance

“…Furthermore, in order to understand the predictive capability of this approach to drug dosimetry, there is also a requirement to determine how well MDCT and CBCT visualize the distribution of the beads in the tissue. Therefore, comparison of DC Bead LUMI in swine liver imaged by MDCT, CBCT and micro-CT has been undertaken, and shows that both MDCT and CBCT under-report the bead distribution density as their resolution is much lower than micro-CT [92,93]. With this knowledge, allowance can be built into predictive software to allow an estimate for unseen beads present between the larger main vessels that are more easily visualized.…”

Cone-Beam Computed Tomography-Based Spatial Prediction of Drug Dose After Transarterial Chemoembolization Using Radiopaque Drug-Eluting Beads in Woodchuck Hepatocellular Carcinoma

“…Also, very low DEB densities may be undetectable on clinical imaging, but the effect on drug dose estimation is unknown. 21 Drug levels in tumor samples were correlated with iodine levels measured using a cone-beam CT of frozen liver ex-plants. HU values may differ slightly for cone-beam CT of liver and radiopaque DEBs in vivo.…”

“…This effect was minimized by waiting 45 minutes for contrast to clear after completion of embolization before imaging and tissue collection. Also, very low DEB densities may be undetectable on clinical imaging, but the effect on drug dose estimation is unknown 21 . Drug levels in tumor samples were correlated with iodine levels measured using a cone-beam CT of frozen liver explants.…”

“…The ratio of the HU-iodine conversion factors at 120 and 100 kVp (1 mg iodine/mL per 46.5 HU; see Supplemental Fig. S1, http://links.lww.com/RLI/A684) was used as a post hoc correction factor for the iodine measurements based on cone-beam CT scans acquired at 100 kVp, since radiopaque DEB detection is greater with the 100 kVp scan than at 120 kVp 21 . Validation of this method was performed by acquiring software iodine measurements using cone-beam CT scans of solutions of known iodine concentration (see Supplemental Fig.…”