title: Body physique and heart rate variability determine the occurrence of stair-step artefacts in 64-slice CT coronary angiography with prospective ECG-triggering.
abstract: The purpose of this study was to describe and characterize the frequency and extent of stair-step artefacts in computed tomography coronary angiography (CTCA) with prospective electrocardiogram (ECG)-triggering and to identify their determinants. One hundred and forty three consecutive patients (55 women, mean age 57 +/- 13 years) underwent 64-slice CTCA using prospective ECG-triggering. Occurrence of stair-step artefacts in CTCA of the thoracic wall and the coronary arteries was determined and maximum offset was measured. If stair-step artefacts occurred in both cases, a difference between thoracic wall and coronary artery offset of 0.6 mm or greater was attributed to additional motion of the heart. Mean effective radiation dose was 2.1 +/- 0.7 mSv (range 1.0-3.5 mSv). Eighty-nine patients (62%) had stair-step artefacts in CTCA of the coronary arteries (mean offset of 1.7 +/- 1.1 mm), while only 77 patients had thoracic wall stair-step artefacts (mean offset of 1.0 +/- 0.3 mm; significantly different, P < 0.001). Stair-step artefacts in CTCA of the thoracic wall were determined by BMI and weight (P < 0.01), while artefacts in CTCA of the coronary arteries were associated with heart rate variability (P < 0.05). Stair-step artefacts in CTCA with prospective ECG-triggering are determined by (a) motion of the entire patient during table travel, particularly in large patients and (b) by motion of the heart, particularly when heart rates are variable.
authors.affiliation: Nuclear Cardiology, University Hospital Zurich, Ramistrasse 100, 8091, Zurich, Switzerland.
authors.forename: Lars
authors.initials: L
authors.lastname: Husmann
authors.forename: Bernhard A
authors.initials: BA
authors.lastname: Herzog
authors.forename: Nina
authors.initials: N
authors.lastname: Burkhard
authors.forename: Fuminari
authors.initials: F
authors.lastname: Tatsugami
authors.forename: Ines
authors.initials: I
authors.lastname: Valenta
authors.forename: Oliver
authors.initials: O
authors.lastname: Gaemperli
authors.forename: Christophe A
authors.initials: CA
authors.lastname: Wyss
authors.forename: Ulf
authors.initials: U
authors.lastname: Landmesser
authors.forename: Philipp A
authors.initials: PA
authors.lastname: Kaufmann
mesh_terms: D016477:Artifacts; D001824:Body Constitution; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D011856:Radiographic Image Enhancement / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*