The aim of this study is to determine the efficacy of atorvastatin in the prevention of contrast-induced nephropathy in patients undergoing computed tomography coronary angiography. Investigators assume that atorvastatin is effective in this regard. Investigators include patients referring for elective computed tomography coronary angiography and allocate them to atorvastatin or placebo from 24 hours before to 48 hours after administration of contrast material. Investigators then measure serum creatinine and see if it is raised by ≥ 0.5 mg/dL or ≥ 25% of the baseline value.

Inclusion Criteria:

• adult patients
• candidate of elective computed tomography angiogram
• willingness to participate

Exclusion Criteria:

• unstable angina or myocardial infarction, cardiac arrhythmia, seizures, acute renal failure, end-stage renal disease
• unstable serum creatinine
• unstable hemodynamic
• intravascular administration of contrast material in the past month
• using high dose atorvastatin in the past month,
• known hypersensitivity to atorvastatin