Intravenous contrast medium administration at 128 multidetector row CT pulmonary angiography: Bolus tracking versus test bolus and the implications for diagnostic quality and effective dose

Aim To investigate the effects of a test bolus protocol contrast medium administration on diagnostic image quality in computed tomography pulmonary angiography (CTPA). Materials and methods Fifty patients referred for exclusion of pulmonary embolism underwent CTPA using a test bolus protocol CTPA at 120 kVp and were compared with 50 patients undergoing CTPA using a standard bolus-tracking protocol at 120 kVp, via assessment of attenuation, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) seen in the pulmonary arteries (PAs). An additional group of 10 non-obese patients who underwent CTPA using a test bolus protocol performed at 100 kVp were also analysed. Mean effective dose was calculated from the dose–length product, using standard conversion factors. Results The test bolus protocol showed significantly higher attenuation, SNR, and CNR in the pulmonary vasculature down to the segmental level compared to bolus-tracking CTPA ( p