title: High-pitch prospective ECG-triggered helical coronary computed tomography angiography in clinical practice: image quality and radiation dose.
abstract: High-pitch prospective ECG-triggered helical (PTH) protocols for coronary computed tomography angiography (CCTA) have demonstrated adequate image quality (IQ) in small-scaled studies and highly selected patients. Clinical applicability in a general clinical population is uncertain. This study evaluated the implementation of a PTH protocol in a routine clinical cohort, focusing on IQ and radiation dose. The local scientific board approved the retrospective analysis and all patients signed an informed consent statement for usage of their data. In consecutive patients suspected of coronary artery disease CCTA was performed using a dual source 128-slice scanner. All patients with a regular heart rate <65 bpm underwent a PTH CCTA. IQ for each coronary segment was graded (1 = absence of artifacts to 4 = non-evaluable). In 664 (80.4 %) of 826 included patients [mean age ± standard deviation (SD) 57 ± 11, 65 % female, mean body mass index (BMI) ± SD 27 ± 9 kg m(-2)] PTH CCTA was acquired whereas in 162 (19.6 %) a non-PTH sequence was used. Reasons for not performing a PTH protocol were persistent high heart rate (41.6 %) or heart rate irregularity (58.4 %). Mean ± SD heart rates for PTH and non-PTH CCTA were 55 ± 5 and 65 ± 9 bpm, respectively, p < 0.001. In the PTH group 92 % of the segments were of diagnostic quality (score 1-3), versus 87 % in the non-PTH group (p = 0.055). Per patient, mean IQ score was 1.19 and 1.21 respectively (lower is better; p = 0.012). Effective dose (including topogram, test bolus, and coronary calcium score), as calculated with a conversion factor of 0.014 mSv mGy(-1) cm(-1) was 1.6 ± 0.6 and 4.7 ± 2.6 mSv for the PTH and the non-PTH group respectively, (p < 0.001). Performing high-pitch PTH sequences on a routine basis is feasible in the majority of patients with high IQ and significant reduction in radiation dose.
authors.affiliation: Department of Cardiology, Medisch Centrum Alkmaar, Alkmaar, The Netherlands, k.bogaard@rijnland.nl.
authors.forename: Kjell
authors.initials: K
authors.lastname: Bogaard
authors.forename: Friso M
authors.initials: FM
authors.lastname: van der Zant
authors.forename: Remco J J
authors.initials: RJ
authors.lastname: Knol
authors.forename: Sjoerd
authors.initials: S
authors.lastname: Reinders
authors.forename: Marije M G
authors.initials: MM
authors.lastname: Krul
authors.forename: Albert C
authors.initials: AC
authors.lastname: van Rossum
authors.forename: Paul
authors.initials: P
authors.lastname: Knaapen
authors.forename: Jan H
authors.initials: JH
authors.lastname: Cornel
mesh_terms: D000368:Aged; D016477:Artifacts; D055424:Cardiac-Gated Imaging Techniques; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000503:physiopathology; D004562:Electrocardiography; D005240:Feasibility Studies; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D011237:Predictive Value of Tests; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D012189:Retrospective Studies; D012720:Severity of Illness Index; D036542:Tomography, Spiral Computed