Abstract 2618: Influence of Heart Rate on the Presence of Motion Artefacts and Image Reconstruction With Dual Source Computed Tomography Coronary Angiography
Purpose: To investigate influence of heart rate on the presence of motion artefacts and image reconstruction interval providing optimal image quality using Dual Source CT (DSCT) Coronary Angiography.
Material and Methods: We studied 30 patients (24 men; mean age, 66±13.2) with atypical chest pain, stable or unstable angina pectoris, or non-ST-segment elevation myocardial infarction, scheduled for diagnostic conventional coronary angiography. All patients were scanned with a DSCT scanner (Somatom Definition, Siemens Medical Solutions Forcheim, Germany) equipped with an improved temporal resolution of 83 ms. Only patients in sinus rhythm were included. Patients with contra-indications to Iodinated contrast material were excluded. No β-blockers were administered prior to the scan. A bolus of 70 ml of high Iodine contrast material was injected at 5 ml/s followed by a saline chaser of 50 ml at 5 ml/s. Mean scan time was 7.8±1.9s. Pitch varied between 0.2 and 0.5. Datasets were standard reconstructed during the mid-to-end diastolic and end-systolic phase using a single-segment ECG-gated reconstruction algorithm. Patients were classified in 3 groups: patients with low (group 1:<60 bpm) 27% (8 of 30), intermediate (group 2:60 – 80 bpm) 43% (13 of 30) and high heart rates (group 3: >80bpm) 30% (9 of 30). Image quality was classified by 2 independent observers as good, adequate or poor, based on the presence of motion artefacts, on a per-segment level.
Results: A total of 347 segments were evaluated. Poor image quality was seen in 0% (2 of 347) of segments in group 1, in 3% (11 of 347) in group 2, and in 6% (21 of 347) in group 3. Optimal image quality was seen in the mid-to-end diastolic phase in 93% (323 of 347) of segments in group 1, in 65% (226 of 347) in group 2, and in 23% (80 of 347) in group 3.
Conclusion: Motion artefacts are reduced due to improved temporal resolution of 83 ms, thereby providing nearly motion-free image quality in patients with high heart rates. End-systolic reconstructions provide optimal image quality in patients with fast heart rates.