What is the chest x-ray finding in a L-R shunt? Differentiate pulmonary arterial from pulmonary venous congestion. Question No.4

X-ray finding in Left to Right Shunt ↑ pulmonary vasculature- increase in the caliber and prominence of both upper and lower lobe blood vessels centrally, in midlung and in the periphery. Engorged hilar arteries Right descending pulmonary artery > 1.1cm Specific cardiac chamber enlargement

ASDVSDPDAPAPVR CARDIAC SIZE↑↑↑↑ Pulmonary Vascularity ↑↑↑↑ Main Pulmo Artery Segment Prominent LVNormalEnlarged Normal LANormalEnlarged Normal RVEnlargedNormal Enlarged RAEnlargedNormal Enlarged AortaSmall EnlargedSmall Charactistic feature Absent LAE Enlarged AortaSchimitar Sign

Pulmonary Arterial Congestion Pulmonary Venous Congestion Active congestion Pulmonary arterial hypertension Constricted arterial vessels ↓pulmonary vasculature on CXR findings Dilated hilar trunks Seen in ASD, VSD, PDA Passive congestion Pulmonary venous hypertension ↑ prominence and thickening of upper lobe vessels ↓ prominence of lower lobed vessels Hazy hilar vessels present Roentgen features of Kerley A, B, C lines Kerley B Lines= pulmonary venous pressure is at mmHg Pulmonary edema= > 25 mmHg Seen in left sided obstruction such as mitral or aortic valve defects ( regurgitation and stenosis)