Blooming artifact (CT)

Blooming artifact in CT is caused by small, high density structures such as artery calcifications and metallic objects, which appear larger than their true size.

The cause of the artifact is that the high Hounsfield value of such objects coupled with the use of smoothing filter kernels results in saturated pixels, due to which these structures can seemingly appear larger than their real size. It can result in e.g. an overestimation of atherosclerotic arterial narrowing, or lead to underestimation/missing a subdural collection.

Possible solutions are increasing the window width, use of sharper filter kernels and iterative reconstruction algorithms, thinner slice thickness, and by reducing the field of view for better spatial resolution .