1-6-4-Pulmonary embolism

1-CT is the examination of choice nowdays.

2-Acute embolus:

-An intraluminal filling defect that fills part of the vessel.

-Complete obstruction is less common.

-Large clots are usually elongated, if it occurs at the site of bifurcation of pulmonary artery, it is known as saddle embolus.

-Small distal emboli are difficult to be seen.

Pulmonary embolus in the left main pulmonary artery.

Saddle pulmonary embolus

--If you an opacity in the artery and another one in the lung, so you are sure that the one in the lung is due to pulmonary infarction resulting from pulmonary embolism.

An opacity situated peripherally in the right lung due infarction

--You cannot say that this lung opacity is due to infarction except if you have clinical history or you do CT pulmonary angiography CT for the patient.

-By spiral CT, you can see embolus in the main pulmonary branches.

-To see more peripheral emboli, you needs to use multidetector CT.

-CT is more preferred than MRI in this situation because it needs less time where the time is crucial for the condition of the patient, MRI can be done for patient with contrast sensitivity.One of the most important benefit of CT over MRI is that by CT we can diagnose the cause of pulmonary embolism as deep venous thrombosis as multidetector CT can imaging the whole body in the same sitting.

Pulmonary embolus affecting peripheral vessel

--Acute thrombus:

Starts small in size than after that begins to increase in size due to aggregation of blood behind it.

-Chronic thrombus:

Starts again to decrease in size eccentric, so you can see the thrombus on one side of the vessel and blood passes from the other side.

-The size of the embolus is not proportional with size of pulmonary infarction, so you can find a big pulmonary embolus with very minimal pulmonary infarcting reaction.

--D.D. from post irradiation pulmonary affection.

-Iodinated oil embolism due to injection of sclerosing material lefted on lipidol to treat varices.