title: Routine helical CT of the abdomen: image quality considerations.
abstract: OBJECTIVE
  Both helical and nonhelical abdominal computed tomographic (CT) scans were obtained to compare image quality, study the effect of patient size and collimation, and compare the frequency of visualization of normal abdominal structures.
  
  
  METHODS
  The study group consisted of 60 consecutive patients with clinically suspected metastatic malignancy.
  
  
  RESULTS
  Both helical and nonhelical image quality was excellent, with equal mean image quality scores of 4.1 on a 5-point scale. In patients weighing more than 175 lb (79 kg), both helical and nonhelical image quality degraded equally when 5-mm collimation was used; 10-mm collimation resulted in excellent image quality, regardless of patient size. Small in-plane structures (eg, renal arteries, renal veins, pancreatic duct) were seen best on helical scans. With the addition of retrospectively reconstructed overlapping images, improvement in visualization of these structures was statistically significant.
  
  
  CONCLUSIONS
  Helical CT scanning should be the preferred means of acquiring routine abdominal CT images.
authors.affiliation: Department of Radiology, Georgetown University Medical Center, Washington, DC 20007.
authors.forename: R K
authors.initials: RK
authors.lastname: Zeman
authors.forename: A S
authors.initials: AS
authors.lastname: Zeiberg
authors.forename: W J
authors.initials: WJ
authors.lastname: Davros
authors.forename: S M
authors.initials: SM
authors.lastname: Ascher
authors.forename: C J
authors.initials: CJ
authors.lastname: Cooper
authors.forename: D I
authors.initials: DI
authors.lastname: Weltman
authors.forename: R
authors.initials: R
authors.lastname: Patt
authors.forename: B S
authors.initials: BS
authors.lastname: Garra
authors.forename: D L
authors.initials: DL
authors.lastname: Griego
authors.forename: P M
authors.initials: PM
authors.lastname: Silverman
mesh_terms: D000008:Abdominal Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D016477:Artifacts; D001943:Breast Neoplasms / Q000473:pathology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007472:Iohexol; D008223:Lymphoma / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010183:Pancreatic Ducts / Q000000981:diagnostic imaging; D011446:Prospective Studies; D011856:Radiographic Image Enhancement / Q000379:methods*; D011860:Radiography, Abdominal; D012077:Renal Artery / Q000000981:diagnostic imaging; D012082:Renal Veins / Q000000981:diagnostic imaging; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D007472:Iohexol