title: Subtraction CT angiography for the diagnosis of iliac arterial steno-occlusive disease.
abstract: OBJECTIVE
  Accurate evaluation of stenosis in severely calcified arteries is a major challenge in conventional CT angiography (CTA) for peripheral arterial disease (PAD). The aim of this study was to evaluate the efficacy of subtraction CTA compared with conventional CTA and conventional angiography.
  
  
  METHODS
  175 arterial segments of 31 consecutive patients with PAD who underwent CTA and subsequent digital subtraction angiography (DSA) were evaluated. The percentage stenosis of diseased arteries was measured in iliac arteries with caliper methods on conventional CTA and subtraction CTA, and the concordance of each CTA method with DSA in the identification of >50 % stenosis was evaluated. Interpretation of CTA was always based only on maximum intensity projection (MIP).
  
  
  RESULTS
  174 (99 %) segments were interpretable on subtraction CTA and showed a good correlation with DSA (R (2) = 0.844), although 55 (31 %) segments were not evaluable on conventional CTA due to severe calcification. On subtraction CTA, the segmental accuracy, sensitivity, and specificity were 90.5, 78.9, and 80.0 %, respectively.
  
  
  CONCLUSIONS
  Subtraction CTA is an accurate diagnostic tool for the evaluation of PAD. It may be easier to interpret stenosis in the presence of calcifications using subtraction CTA rather than with the conventional CTA approach. Also, subtraction CTA using only MIP presented a similar accuracy to DSA.
authors.affiliation: Department of Radiology, Iwate Medical University, 19-1 Uchimaru, Morioka, Iwate, 020-8505, Japan. mamimichiko@gmail.com.
authors.forename: Michiko
authors.initials: M
authors.lastname: Suzuki
authors.affiliation: Department of Radiology, Iwate Medical University, 19-1 Uchimaru, Morioka, Iwate, 020-8505, Japan.
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Tanaka
authors.affiliation: Department of Radiology, Iwate Medical University, 19-1 Uchimaru, Morioka, Iwate, 020-8505, Japan.
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Yoshioka
authors.affiliation: Department of Cardiology, Memorial Heart Center, Iwate Medical University, 1-2-1 Tyuodori, Morioka, Iwate, 020-8505, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Abiko
authors.affiliation: Department of Radiology, Iwate Medical University, 19-1 Uchimaru, Morioka, Iwate, 020-8505, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Ehara
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015901:Angiography, Digital Subtraction / Q000379:methods*; D001157:Arterial Occlusive Diseases / Q000000981:diagnostic imaging*; D000072226:Computed Tomography Angiography / Q000379:methods*; D005260:Female; D006801:Humans; D007083:Iliac Artery / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results
keywords: CT angiography; Digital subtraction angiography; Percentage stenosis; Peripheral arterial disease; Subtraction CT angiography