Impact of Written Informed Consent on the Number of Intravenous Contrast−Enhanced CT and MR Studies

Abstract

The purpose of this study was to evaluate the impact of written informed consent on the number of intravenous contrast-enhanced CT and MR imaging studies. On December 2002, the Conference of Physicians and Medical Directors in our institution decided that all referring physicians must obtain written informed consent in each case before intravenous injection of contrast material for CT and MR imaging studies. The numbers and proportions of contrast-enhanced CT and MR imaging studies before introduction of the written informed consent requirement (January 2002-December 2002) were compared with those after (January 2003-December 2003). The number of contrast-enhanced CT studies decreased from 5930 (50.6% of all CT studies) to 5539 (49.0% of all CT studies) (odd ratio [OR]: 0.94, 95% confidence interval [CI]: 0.89-0.99). The number of contrast-enhanced MR studies also decreased from 1895 (46.5% of all MR studies) to 1712 (43.4% of all MR studies) (OR: 0.88, 95% CI: 0.81-0.96). Findings suggest that the written informed consent requirement reduces the number of intravenous contrast-enhanced CT and MR imaging studies.