David M. Thomas BSC, Presenter: Nothing to Disclose

Sarah Anne Barrett MBBCh, Abstract Co-Author: Nothing to Disclose

Patrick McLaughlin FFR(RCSI), Abstract Co-Author: Nothing to Disclose

John R. Mayo MD, Abstract Co-Author: Speaker, Siemens AG

Ana-Maria Bilawich MD, Abstract Co-Author: Nothing to Disclose

Savvas Nicolaou MD, Abstract Co-Author: Nothing to Disclose

Graham Wong MD, MPH, Abstract Co-Author: Nothing to Disclose

Luck Jan-Luck Louis MD, Abstract Co-Author: Nothing to Disclose

As rotation time, coverage and pitch increase, modern CT systems are more likely able to produce motion free images of the coronary arteries during CTPA scans. The purpose of this study was to compare coronary artery motion and diagnostic acceptability between dual source ultra high pitch (UHP), single source (SS) and dual source dual energy (DE) CTPA studies.

362 consecutive patients underwent CTPA scans for suspected pulmonary embolism between Sept 1, 2013 and Jan 31, 2014. 238 UHP, including 194 at 100kV (UHP-100kV) and 44 at 120kV (UHP-120kV), 57 SS scans, and 37 DE scans were analyzed. Coronary arteries were separated into nine segments, and coronary artery motion was qualitatively scored using a scale from 1-4 (non-interpretable to diagnostic with no motion artifacts) to assess the quality of each protocol for visualization of the coronary arteries. CTDI and DLP values were collected for each scan to determine the effective radiation dose. Signal intensity, noise, and signal to noise ratio (SNR) of the aorta, main pulmonary artery, and paraspinal muscles were also assessed.

The UHP-120kV and UHP-100kV scans had the lowest amount of motion, with 38.8% and 30.1% of coronary segments being evaluable compared to 4.2% of SS segments. Proximal coronaries were more diagnostic than distal coronaries UHP-120kV (53.5% vs 24%, median score 2 vs 1, p0.05), and both were higher than the UHP-100kV group (20.04 vs 15.80, p<0.001).

UHP-120kV CTPA significantly reduced coronary artery motion and allows for accurate evaluation of the proximal coronary arteries compared to SS CTPA, without a statistically significant impact on SNR. UHP-100kV resulted in 77.2% less radiation exposure than SS although it came at the expense of an 18.8% reduction in average SNR.

UHP CTPA protocols can be used to assess the proximal coronary arteries while maintaining the ability to rule in or out pulmonary embolism in patients with chest pain.

Thomas, D, Barrett, S, McLaughlin, P, Mayo, J, Bilawich, A, Nicolaou, S, Wong, G, Louis, L, Dual Source, Ultra High Pitch CT Pulmonary Angiography (CTPA) Reduces Motion and Allows for Accurate Evaluation of the Proximal Coronary Arteries in Approximately 50% of Patients Imaged for Suspected Pulmonary Embolism.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14016917.html