The Vascular Pedicle

The vascular pedicle is bordered on the right by venous structures (right brachiocephalic vein above and superior vena cava) and on the left by an arterial structure (the left subclavian artery origin). The azygos vein (black oval) is seen en face above the right main bronchus.

The vascular pedicle width (VPW) is the distance between parallel lines drawn from the point at which the superior vena cava intersects the right main bronchus an a line drawn at the takeoff of the left subclavian artery from the aorta. The mean vascular pedicle width is 38-58 mm on posteroanterior chest radiographs.

The vascular pedicle width correlates well with systemic blood volume and can help differentiate different forms of pulmonary edema. It is usually normal in acute cardiac failure and wide in overhydration/renal failure pulmonary edema and chronic heart failure. In can be normal or narrowed in capillary permeability pulmonary edema.

References

• Milne EN, Pistolesi M, Miniati M, Giuntini C. The vascular pedicle of the heart and the vena azygos. Part I: The normal subject. Radiology. 1984 Jul;152(1):1-8.
• Milne EN, Pistolesi M, Miniati M, Giuntini C. The radiologic distinction of cardiogenic and noncardiogenic edema. AJR Am J Roentgenol. 1985 May;144(5):879-94.