Multidetector CT pulmonary angiography features of pulmonary embolus

Abstract

Pulmonary embolism (PE) is a life-threatening condition. Multidetector CT pulmonary angiography is currently the imaging method of choice for the detection of PE. The aim of this pictorial essay is to review the appearances of PE on multidetector CT pulmonary angiography, including signs that differentiate acute and chronic PE and markers of severity. The features of a non-diagnostic study and pitfalls leading to a false-positive or false-negative study are presented.

Imaging in thromboembolic disease

“…When it comes to documenting the sites of acute PE, the pulmonary arteries are ordered by size with the main pulmonary arteries (main, right and left) representing the first order, lobar arteries are second order, segmental arteries are third order and the subsegmental arteries are fourth order [9]. Acute PE also occurs more commonly in the lower lobe pulmonary arteries because of increased perfusion here.…”

“…At the level of the thrombus, the vessel is usually enlarged due to impaction of thrombus by pulsatile flow [9]. Acute PE that is not completely occluding the artery and is centrally placed will be surrounded by contrast material producing the 'lifesaver sign' or 'polo mint sign' on an image acquired transversely or the 'railway track sign' on an image obtained parallel to the artery (Figure 4 &Supplementary Figure 4) [9]. Acute PE that is not completely occluding the artery and is centrally placed will be surrounded by contrast material producing the 'lifesaver sign' or 'polo mint sign' on an image acquired transversely or the 'railway track sign' on an image obtained parallel to the artery (Figure 4 &Supplementary Figure 4) [9].…”

“…On an image parallel to the vessel, the thrombus has a convex margin (or the intravenous contrast cut-off has a concave margin) (Figure 3). Acute PE that is eccentrically located in the vessel will demonstrate acute angles with the vessel wall and some eccentric contrast enhancement (Supplementary Figure 5) [9]. Acute PE that is eccentrically located in the vessel will demonstrate acute angles with the vessel wall and some eccentric contrast enhancement (Supplementary Figure 5) [9].…”

“…In contrast to an acute PE, the vessel is usually smaller than adjacent arteries, and the thrombus has a straight or concave margin (with the intravenous contrast cut-off seen as a convex margin or 'pouch' defect) [9]. In contrast to an acute PE, the vessel is usually smaller than adjacent arteries, and the thrombus has a straight or concave margin (with the intravenous contrast cut-off seen as a convex margin or 'pouch' defect) [9].…”

Point of care ultrasound in cardiac arrest: A case report of PE in PEA arrest

“…MDCT-PA improved imaging techniques have increased the ability to diagnosis segmental and sub-segmental emboli and has led to a better estimation of the overall thrombus burden. These improvements have led to improved risk stratification for patients, thus allowing better to determine the most appropriate treatment options [32]. However, in the hemodynamically unstable patient, this is not an option.…”