Carotid ultrasound is a technically exam dreaded by even many otherwise experienced examiners. A key reason is the rigorous attention to details and technical parameters that need to be followed in order to get reliable results. Small changes in angle of insonation, or poor positioning of the sampling gate can lead to unreliable measurements. These can result in tremendous under/overestimation of the degree of stenosis. Things are further complicated by the multitude of quantitative and velocity parameters which can be obtained. Unfortunately on US eyeballing the stenosis is also unlikely produce a reliable result since in practice the acoustic shadowing and artifacts makes this often impossible in the most important advanced plaques and narrowings.
To overcome at least some of the hurdles several societies and organizations released consensus criteria putting the level of stenosis into distinct subcategories primarily based on systolic velocity and visual assessment. Today I have made available a carotid stenosis calculator based on the Society of Radiologists in Ultrasound (SRU) consensus criteria which is uses internal carotid artery (ICA) peak systolic velocity and grayscale/Doppler appeareance as the main criteria, while other parameters (ICA/CCA PSV ratio, ICA end diastolic velocity) can be used as ancillary features and for troubleshooting.
Incidentally found indeterminate lung lesions and their further management is again a challenge most of us face every day. The Fleischner Society recommendation aim to ease the dilemma by offering specific follow-up recommendations based on lesion morphology and size, and also specify clear thresholds below which routine follow-up is generally not mandated. While in daily practice caliper measurements done in standard imaging planes are still the most widely used parameter to express nodule size, the importance (and availability) of nodule volumetry is growing. Thus two calculators have been made, a diameter-based one (using long and short axis diameters), and a volume-based calculator. Both calculators reflect the latest, 2017 version of the Fleischner Society recommendations.