Beaded Pulmonary Arteries

Intravascular pulmonary tumor emboli can result in a dilated and beaded appearance of medium to small pulmonary arteries distended by tumor.

Lymphangitic spread of tumor through pulmonary capillaries, lymphatic vessels, and the septal interstitium, on the other hand, results in nodular thickening of the interlobular septa (the so-called beaded septum sign).

Plugged dilated bronchi and pulmonary anteriovenous malformations may have a similar appearance at first glance. The former is diagnosed by noting communication with the bronchial tree, while the latter can be diagnosed by noting connection to a draining vein.

References

• Ren H, Hruban RH, Kuhlman JE, Fishman EK, Wheeler PS, Zerhouni EA, Hutchins GM. Computed tomography of inflation-fixed lungs: the beaded septum sign of pulmonary metastases. J Comput Assist Tomogr. 1989 May-Jun;13(3):411-6.
• Shepard JA, Moore EH, Templeton PA, McLoud TC. Pulmonary intravascular tumor emboli: dilated and beaded peripheral pulmonary arteries at CT. Radiology. 1993 Jun;187(3):797-801.