The Three Planes / Views I like to start this section by highlighting the famous short story of blind men and the elephant. For those of you who aren’t familiar with the story, you can read it here. In summary, each blind man encounters different part of the elephant. One man felt the elephant’s leg
The Hounsfield Unit, Window Level & Width The Hounsfield Unit The Hounsfield Unit (HU) is a way to (quantitatively) measure tissue density. More dense structure absorbed more radiation = image is brighter e.g. bone (+1000 HU) Less dense structure absorbed less radiation = image is darker e.g. air (-1000 HU) The reference point is water,
Pulmonary Embolism What’s normal ? For further details on CTPA please see specific section on CTPA and CT angiogram. In summary, the contrast helps to enhance the outline of the vessels. The normal CTPA has continuous flow of hyper-attenuated contrast within the vasculature of pulmonary artery (PA) and its branches. Figure 1: CT chest without