2018 JTI (Image quality of SSF in ts with high HR)

Purpose: Recently, a new intracycle motion correction algorithm
(MCA) was introduced to reduce motion artifacts from heart rate
(HR) in coronary computed tomography angiography (cCTA). The
aim of the study was to evaluate the image quality, overall evaluability,
and effective radiation dose (ED) of cCTA with prospective
electrocardiographic (ECG) triggering plus MCA as compared with
standard protocol with retrospective ECG triggering in patients
with HR≥65 bpm.
Materials and Methods: One hundred consecutive patients
(67±10 y) scheduled for cCTA with 65<HR<80 bpm were retrospectively
analyzed. The patients were assigned to 2 groups undergoing
prospective (group 1) or retrospective (group 2) triggered
cCTA. The study protocol was approved by the Institutional Ethics
Committee and a written informed consent was obtained from all
patients. Image noise, signal to noise ratio, contrast to noise ratio,
Likert image quality score (score 1, nondiagnostic; score 2, adequate;
score 3, good; score 4, excellent), overall image evaluability,
and ED were measured and compared between the 2 groups. Both
vessel-based and patient-based analyses were evaluated. Student test
or Wilcoxon test were used to evaluate differences of continuous
variables, whereas the χ2 test was used to study differences with
regard to categorical data. A P-value <0.05 was considered statistically
significant.
Results: cCTA was successfully performed in all patients. In a segment-
based model, group 1 compared with group 2 showed a lower
rate of overall artifacts (67% vs. 83%; P< 0.001) and motion artifacts
(49% vs. 66%; P<0.001), resulting in a better Likert image
quality score (2.83±1.03 vs. 2.37±1.02; P<0.01) and overall
evaluability (85% vs. 75%; P<0.01). Group 1 showed a lower ED
as compared with group 2 (3.1±1.9 vs. 11.9±3.3 mSv; P< 0.01).
Conclusion: MCA and cCTA with prospective ECG-triggering
acquisition in patients with high HR improves image quality and
overall evaluability compared with cCTA with standard retrospective
ECG triggering.
Key Words: heart rate, prospective triggering, retrospective triggering,
intracycle motion correction algorithm, effective radiation dose