Electrocardiographically gated thin-section CT of the lung

PURPOSE: To determine whether electrocardiographic (ECC) gating improves image quality of thin-section computed tomographic (CT) scans of the lung obtained with a subsecond CT scanner. MATERIALS AND METHODS: Thin-section CT was performed in 35 patients by using standard techniques. Three additional sections were obtained in each patient with prospective ECC gating at corresponding levels of the paracardiac lung parenchyma. Non-EGG-gated and EGG-gated sections were then rated in blinded fashion by three experienced radiologists for overall image quality, spatial resolution, and diagnostic value and for different types of respiratory and cardiac motion artifacts. RESULTS: ECC gating helped significantly reduce artifacts caused by cardiac motion tie, distortion of pulmonary vessels, double images, or blurring of the cardiac border) (P <.05). ECG gating did not reduce respiratory motion artifacts. In patients with heart rates of less than 76 beats per minute, ECC gating significantly improved overall image quality (P =.041). ECG gating was not perceived to increase the diagnostic value of thin-section CT scans. CONCLUSION: ECC gating improves image quality of thin-section CT scans of the lung by reducing cardiac motion artifacts that may mimic disease. It must be established whether ECG gating can help increase the diagnostic accuracy of thin-section CT for the evaluation of subtle parenchymal disease.