title: Efficacy of 'fine' focal spot imaging in CT abdominal angiography.
abstract: OBJECTIVE
  To assess the efficacy of fine focal spot imaging in calcification beam-hardening artefact reduction and vessel clarity on CT abdominal angiography (CTAA).
  
  
  METHODS
  Adult patients of any age and gender who presented for CTAA were included. Thirty-nine patients were examined with a standard focal spot size (SFSS) of 1 × 1 mm in the first 3 months while 31 consecutive patients were examined with a fine focal spot size (FFSS) of 1 × 0.5 mm in the following 3 months. Vessel clarity and calcification beam-hardening artefacts of the abdominal aorta, celiac axis, superior mesenteric artery, inferior mesenteric artery, renal arteries, and iliac arteries were assessed using a 5-point grading scale by two blinded radiologists randomly.
  
  
  RESULTS
  Cohen's Kappa test indicated that on average, there was substantial agreement among reviewers for vessel wall clarity and calcification artefact grading. Mann-Whitney test showed that there was a significant difference between the two groups, with FFSS performing significantly better for vessel clarity (U, 6481.50; p < 0.001; r, 0.73) and calcification artefact reduction (U, 1916; p < 0.001; r, 0.77).
  
  
  CONCLUSIONS
  Fine focus CT angiography produces images with better vessel wall clarity and less vessel calcification beam-hardening artefact.
  
  
  CONCLUSIONS
  Focal spot size affects the spatial resolution of a CT system. Fine focus CTAA produces images with improved vessel wall clarity. Fine focus CTAA is associated with fewer calcification beam-hardening artefacts. Fine focus CTAA may improve accuracy in assessment of luminal stenosis.
authors.affiliation: Department of Diagnostic Imaging, Monash Health, 246 Clayton Road, Clayton, 3168, Victoria, Australia, chia.wei.oh@gmail.com.
authors.forename: Lawrence Chia Wei
authors.initials: LC
authors.lastname: Oh
authors.forename: Kenneth K
authors.initials: KK
authors.lastname: Lau
authors.forename: Ashwini
authors.initials: A
authors.lastname: Devapalasundaram
authors.forename: Kevin
authors.initials: K
authors.lastname: Buchan
authors.forename: Nicholas
authors.initials: N
authors.lastname: Ardley
authors.forename: Minh
authors.initials: M
authors.lastname: Huynh
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography / Q000379:methods; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging; D001018:Aortic Diseases / Q000000981:diagnostic imaging; D001157:Arterial Occlusive Diseases / Q000000981:diagnostic imaging*; D016477:Artifacts; D005260:Female; D006801:Humans; D007083:Iliac Artery / Q000000981:diagnostic imaging; D008297:Male; D017537:Mesenteric Artery, Inferior / Q000000981:diagnostic imaging; D017538:Mesenteric Artery, Superior / Q000000981:diagnostic imaging; D008641:Mesenteric Vascular Occlusion / Q000000981:diagnostic imaging; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods*; D011446:Prospective Studies; D011860:Radiography, Abdominal / Q000379:methods*; D012078:Renal Artery Obstruction / Q000000981:diagnostic imaging; D061205:Vascular Calcification / Q000000981:diagnostic imaging; D055815:Young Adult
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