The Efficacy of Papaverine to Prevent Radial Artery Spasm During Transradial Cerebral Angiography

Inclusion Criteria: 1. All patients scheduled for cerebral angiography will be eligible for screening. 2. Participant is willing and is able to give informed consent for participating in the trial. 3. Male or Female, aged 18 years or above. Exclusion Criteria: 1. Any patient with negative modified Allen test 2. Altered liver function 3. atrioventricular heart block III degree 4. Suspected or confirmed cerebral hemorrhage patients 5. Hemodynamic Instability : systolic pressure \< 100 mmHg, heart rate \> 100 bpm, tachycardia uncontrollable. 6. Patients with cerebral edema and increased intracranial pressure within 24 hours to 2 weeks after stroke 7. Coronary artery bypass grafting(CABG) operation history and whose right radial artery is missing as a "bridge vessel" 8. Severe skin musculoskeletal malformation of forearm or failure to complete radial artery puncture and sheath placement for other reasons 9. Hypersensitivity or contraindication to papaverine 10. Hypersensitivity or contraindication to nitroglycerine 11. Glaucomatous patients 12. Parkinson's disease patients 13. Women who are suspected or known to be pregnant or breastfeeding