PURPOSE: The purpose of this study was to establish, using computed tomography, the normal thickness of thepericardium in adults. MATERIALS AND METHODS: CT scans of 50 patients, including sections through the level of theheart, were reviewed. Patients were excluded if there were any suspicions of pericardial abnormality such asinfectious or neoplastic diseases. Twenty-four of the 50 were men and 26 were women; their mean age was 47.0(range,18-76) years. We measured pericardial thickness at the level of the right ventricle, interventricularseptum and left ventricle, and also compared pericardial thickness in terms of age and sex. RESULTS: In allpatients, the pericardium was observed in the right ventricular region; in 41 (82%) at the interventricularseptum; and in 41 (82%) along the left ventricle. The mean thickness of normal pericardium at the level of theright ventricle, interventricular septum, and left ventricle was 1.8 mm +/- 0.5 mm, 1.8 mm +/- 0.4 mm, and 1.7 mm +/-0.5 mm, respectively. No statistically significant correlation was apparent between pericardial thickness and agegroup (p > 0.63, ANOVA test). Mean pericardial thickness was 1.9 mm +/- 0.6 mm in males and 1.7 mm +/- 0.4 mm in females; thus, no statistically significant correlation was apparent between pericardial thickness and sex (p >0.29, Student's t-test). CONCLUSION: The pericardium was best visualized in sections through the right ventricle.The mean thickness of normal pericardium was 1.8 mm +/- 0.5 mm and pericardial thickness did not differ accordingto age or sex.