title: Optimization of the table speed of lower extremity CT angiography protocols in different patient age groups.
abstract: BACKGROUND
  Scanning with 64-slice multidetector row CT (MDCT) is usually faster than blood flow in peripheral arteries of the lower extremities, and the distal arteries of lower extremities are difficult to visualize, particularly in elderly patients. Thus, the optimal table speed for CT angiography (CTA) studies should be adjusted for appropriate patient age groups.
  
  
  OBJECTIVE
  We evaluated the relative efficacy of different table speeds in several age groups of patients with suspected peripheral arterial occlusive disease (PAOD) undergoing CTA of lower extremity arteries, as a guideline for routine use.
  
  
  METHODS
  This retrospective study reviewed routine CTA of the lower extremity arteries of 107 patients with suspected PAOD to evaluate vascular opacification in each vascular segment of 5 age groups: < or =40 years (group 1), 41-60 years (group 2), 61-70 years (group 3), 71-75 years (group 4), and > or =76 years (group 5). Adequate vascular opacification was measured for attenuation in the suprarenal and infrarenal abdominal aorta and in the arteries of the lower extremity. Venous contamination was also measured.
  
  
  RESULTS
  Adequate vascular opacification from the suprarenal aorta to the level of the mid-popliteal artery was shown in all patients. Arterial opacification at the dorsalis pedis or plantar arteries was visualized in 85.7%-91.7% of patients and at the plantar arch arteries in 84.1%-91.7%. Minimal venous contamination was also shown adjacent to arterial enhancement, ranging from 0% to 28.6%.
  
  
  CONCLUSIONS
  Performing CTA of the lower extremities with 64-slice MDCT could reduce the table speed to allow adequate arterial opacification and minimal venous contamination.
authors.affiliation: Department of Radiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand 10700. thanongchai@gmail.com
authors.forename: Thanongchai
authors.initials: T
authors.lastname: Siriapisith
authors.forename: Jitladda
authors.initials: J
authors.lastname: Wasinrat
authors.forename: Pramook
authors.initials: P
authors.lastname: Mutirangura
authors.forename: Chanean
authors.initials: C
authors.lastname: Ruangsetakit
authors.forename: Chumpol
authors.initials: C
authors.lastname: Wongwanit
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography / Q000379:methods*; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001027:Aortography / Q000379:methods*; D001157:Arterial Occlusive Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001783:Blood Flow Velocity; D003287:Contrast Media; D005260:Female; D006801:Humans; D035002:Lower Extremity / Q000098:blood supply*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D012039:Regional Blood Flow; D012189:Retrospective Studies; D013785:Thailand; D036542:Tomography, Spiral Computed; D014680:Veins / Q000503:physiopathology
chemical_list: D003287:Contrast Media