The prevalence of nausea and vomiting after the administration of non-ionic contrast media has rarely been assessed. Thus, the aim of our study is to evaluate the prevalence and risk factors of nausea and vomiting after the exposure to the non-ionic contrast media for computed tomography examinations in adults.

There is no robust evidence or guideline for fasting prior to contrast-enhanced CT scan in patients. Substantial heterogeneity exists on fasting prior to contrast-enhanced CT worldwide. Through dedicated questionnaires, the investigators plan to prospectively assess the prevalence and the risk factors for nausea and vomiting after the exposure to the non-ionic contrast media agent in adult patients undergoing computed tomography examinations.

Inclusion criteria:

• Patients undergoing contrast-enhanced CT examination with non-ionic contrast media during regular working hours
• Adult patients (20 years old or older)
• Patients with informed written consent
• Patients under observation by medical staffs during and after CT examination up to 30 minutes.

Exclusion criteria:

• Patients without informed written consent
• Age of patients younger than 20 years old
• Uncooperative patients
• Pediatric, pregnant, and emergent patients
• Patients without sufficient observation by medical staffs during and after CT examination up to 30 minutes.

Patients who undergo elective CT examination after the administration of non-ionic contrast media in a single tertiary hospital will be enrolled based on following inclusion and exclusion criteria.