ROUTINE HELICAL CT OF THE ABDOMEN - IMAGE QUALITY CONSIDERATIONS

PURPOSE: Both helical and nonhelical abdominal computed tomographic (C T) scans were obtained to compare image quality, study the effect of p atient size and collimation, and compare the frequency of visualizatio n of normal abdominal structures. MATERIALS AND METHODS: The study gro up consisted of 60 consecutive patients with clinically suspected meta static malignancy. RESULTS: Both helical and nonhelical image quality was excellent, with equal mean image quality scores of 4.1 on a 5-poin t scale. In patients weighing more than 175 lb (79 kg), both helical a nd nonhelical image quality degraded equally when 5-mm collimation was used; 10-mm collimation resulted in excellent image quality, regardle ss of patient size. Small in-plane structures (eg, renal arteries, ren al veins, pancreatic duct) were seen best on helical scans. With the a ddition of retrospectively reconstructed overlapping images, improveme nt in visualization of these structures was statistically significant. CONCLUSION: Helical CT scanning should be the preferred means of acqu iring routine abdominal CT images.