Optimisation of radiation dose and contrast medium injection remains an important issue in MDCT, in order to get good image quality with a good compromise between radiation dose and contrast medium delivery. Contrast-to-noise ratio (CNR) is, in practice, an indicator to evaluate image quality in an objective fashion. Recent literature showed that low kilovoltage settings in selected slim patients are adequate for contrast-enhanced acquisitions. A first attempt was provided in the field of cardiac CT using dedicated low-kilovoltage protocols in patients undergoing coronary CT angiography [ 1 ].
A new phantom study by Szucs-Farkas et al. [ 2 ], recently published in Investigative Radiology, evaluated the CNR in pulmonary CT angiography for 300 and 400 mg iodine/mL contrast media using variable X-ray tube parameters and patient sizes.