Low Iodine Concentrations During DECT Yield Improved Uric Acid Detection

A phantom study and clinical illustration published in European Radiology Experimental found that the use of lower iodinated contrast medium (ICM) concentrations improved detection of low and medium uric acid concentrations with dual-energy computed tomography (DECT) in patients with gouty arthritis.

“Since patients with unclear arthritis undergoing contrast-enhanced multiparametric DECT may also suffer from gout, currently an unenhanced DECT is performed routinely beforehand due to the unknown effect of ICM on the detection of [monosodium urate (MSU)],” the investigators wrote. “Therefore, the aim of this study was to systematically analyze whether, and if so how, the presence of ICM influences the detection of MSU in different ex vivo phantom settings.”

The study included 2 types of phantoms—a grid-like phantom and a biophantom—each having suspensions with varying concentrations of ICM (range, 0%-2%) and MSU (range, 0%-50%). Through a series of DECT scans, the researchers explored how different ICM concentrations affected the detection of MSU crystals.

Lower concentrations of ICM (0.25% and 0.50%) enhanced the detection of small uric acid concentrations by an impressive 35% to 45% compared with scans conducted without ICM. “However, high ICM concentrations (1% and 2%) almost completely precluded MSU detection for all MSU concentrations investigated,” according to the researchers.

The researchers also presented a real-world case of a patient suffering from gouty arthritis. The results of the clinical example found that the visualization of tophi in the wrist was only achieved after intravenous administration of ICM.

“The clinical impact of our findings has yet to be demonstrated in further studies,” they concluded. “For now, the authors recommend adding an unenhanced scan to contrast-enhanced protocols when gouty arthritis is suspected.”