A case of massive transient reduction of attenuation of iodine contrast bolus during computed tomography pulmonary angiography: why and how to avoid it.

We report an incidental case of combined disproportionate deep inspiration and breath-old artifacts producing during computed tomography pulmonary angiography performed to exclude pulmonary embolism in a 69-year-old patient. These known but unwelcome cumulated artifacts may cause transient major attenuation or interruption of the contrast bolus which may occasionally obscure or mimic an embolus. We shortly review the mechanisms of these classical artifacts and the adequate breathing instructions to avoid them are remembered.