Contrast‐enhanced ultrasound studies registered on ClinicalTrials.gov: A cross‐sectional analysis of characteristics, early discontinuation, and reporting results

Abstract

A data set containing all contrast-enhanced ultrasound clinical studies from ClinicalTrials.gov registered was downloaded. Then, a cross-sectional descriptive study of clinical contrast-enhanced ultrasound studies was conducted. Cox and logistic regression of early discontinuation and reported results, respectively, were also performed. A total of 225 studies were identified; 174 were interventional and 51 were observational. Regarding the outcomes measure, 175 (77.78%) were diagnosis-oriented, and the remaining 50 (22.22%) were interventional radiology studies. The most common regions of interest were abdominal (56%), superficial (14.22%), or vascular (7.11%) organs. As of the contrast agents, SonoVue/Lumason (39.11%) was most frequently used, followed by Definity (20.89%) and Sonazoid (8.89%). Of all contrast-enhanced ultrasound studies, 32 (14.22%) were discontinued early, and 29 (12.89%) completed studies reported their results. Cox regression analysis revealed that a large sample size and US registration were factors reducing early discontinuation risk. Among completed studies, factors associated with reported results were industry funding and US registration. The findings suggest that the number of contrast-enhanced ultrasound studies has grown over time, but is still small. Developing new advancements in contrast-enhanced ultrasound will require a concerted effort to increase the quality and quantity of clinical studies in this field.