Characterization of a Novel Hafnium-Based X-ray Contrast Agent

Abstract

The profile of BAY-576 indicates its potential as the first compound in a new class of noniodine x-ray contrast agents, which can contribute to the reduction of the radiation burden in contrast-enhanced CT imaging.

Improved Calcium Scoring at Dual-Energy Computed Tomography Angiography Using a High-Z Contrast Element and Novel Material Separation Technique

“…In addition, development of tungsten trioxide (WO 3 ) nanoparticle agents, coated with either chitosan (41) or poly-ε-caprolactone (42) display similar properties that are promising for further development. Agents based on several other high-Z elements such as gold (43) ytterbium (44), bismuth (45), tantalum (46) and hafnium (47) have also been proposed. Such agents would share the properties exhibited by tungsten, as most high-Z elements also show dual energy ratios of ~1 (18, 34).…”

“…Gadolinium also raises toxicity and retention concerns, particularly for the large injected doses required for use as a CT contrast agent compared to MRI (19, 48). Further benefits offered by high-Z contrast elements include greater attenuation and thus brighter image contrast (16, 17, 49), good tolerability (46, 47), utility in double contrast DECT studies (18, 21, 22, 50), and compatibility with metal artifact reduction (27). Agents based on these elements are still however in preclinical toxicity testing stages, with a hafnium chelate (47) and a tantalum nanoparticle-based agent (46) appearing most promising for clinical translation in the medium term.…”

“…Further benefits offered by high-Z contrast elements include greater attenuation and thus brighter image contrast (16, 17, 49), good tolerability (46, 47), utility in double contrast DECT studies (18, 21, 22, 50), and compatibility with metal artifact reduction (27). Agents based on these elements are still however in preclinical toxicity testing stages, with a hafnium chelate (47) and a tantalum nanoparticle-based agent (46) appearing most promising for clinical translation in the medium term. Preclinical injected elemental concentrations of 300 mg/mL and 140 mg/mL have been achieved for hafnium and tantalum respectively, with favorable toxicity results compared to iodine (46, 47).…”

“…Agents based on these elements are still however in preclinical toxicity testing stages, with a hafnium chelate (47) and a tantalum nanoparticle-based agent (46) appearing most promising for clinical translation in the medium term. Preclinical injected elemental concentrations of 300 mg/mL and 140 mg/mL have been achieved for hafnium and tantalum respectively, with favorable toxicity results compared to iodine (46, 47). Both agents remain several years from clinical introduction, however, as safety requirements for intravenously injected contrast agents remain demanding, and regulatory hurdles stringent (19).…”

An Intravascular Tantalum Oxide–based CT Contrast Agent: Preclinical Evaluation Emulating Overweight and Obese Patient Size

“…No adverse effects were seen, and organ retention was similar to that of existing commercial iodine agents in rats (12). However, as with all other preclinical studies of high-atomic-number contrast agents (7,8,10,11,21), the small-animal model precluded anatomically relevant image quality analysis. As such, these key properties remained untested in large-animal models for all high-atomic-number contrast agent candidates.…”