Frequently Encountered Artifacts in the Application of Dual-Energy CT to Cardiovascular Imaging for Urate Crystals in Gout: A Matched-Control Study.

OBJECTIVES: There is surging interest in utilizing dual-energy CT (DECT) to identify cardiovascular monosodium urate (MSU) deposits among gout patients. We sought to examine the prevalence and characterization of cardiovascular DECT artifacts using non-ECG-gated DECT pulmonary angiograms.

METHODS: We retrospectively reviewed non-ECG-gated DECT pulmonary angiograms performed on patients with and without gout at a single academic center. We noted the presence and locations of vascular green colorization using the default post-processing two-material decomposition algorithm for MSU. The high- and low-energy grayscale images and advanced DECT measurements were used to determine if they were true findings or artifacts. We classified artifacts into five categories: streak, contrast medium mixing, misregistration due to motion, foreign body, and noise.

RESULTS: Our study included CT scans from 48 gout patients and 48 age- and sex-matched controls. The majority of patients were males with a mean age of 67 years. Two independent observers attributed all areas of vascular green colorization to artifact. The most common types of artifacts were streak (56% vs. 57% among cases vs. controls, respectively) and contrast medium mixing (51% vs. 65%, respectively). While some of the default DECT measurements of cardiovascular green colorization were consistent with values reported for subcutaneous tophi, advanced DECT measurements were not consistent with that of tophi.

CONCLUSION: Artifacts that could be misconstrued as cardiovascular MSU deposits were commonly identified among patients with and without gout on non-ECG-gated DECT pulmonary angiograms. These artifacts can inform future vascular DECT studies in gout patients to minimize false-positive findings.