Extra [corrected] pulmonary uptake of Tc-99m-MAA perfusion lung scan as a result of right to left intra cardiac shunt.
Extra pulmonary accumulation of Tc-99m-macroaggregate of albumin (MAA) is rarely seen on perfusion lung scan, and has been reported in less than 4% of a study population of nearly 380 patients. It occurs when the agent bypasses the lungs due to a right to left (R-L) cardiac or pulmonary shunt, when it is shunted to the portal vein before reaching the right atrium and ventricle of the heart, and when the agent is degraded to a submicron particle size. When a pharmaceutical problem is excluded, extra-pulmonary uptake implies unusual hemodynamics with a shunt. A case is reported in which a clinically unsuspected shunt was diagnosed from the lung perfusion scintigraphy.
Hussain
Riffat
R
Department of Radiology, Aga Khan University Hospital, Karachi.
Maseeh-uz-Zaman
Khan
Sohail Abrar
SA
Ahmad
M Nadeem
MN
D000328:Adult; D001164:Arteriovenous Fistula / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D006325:Heart Atria / Q000002:abnormalities; D006344:Heart Septal Defects, Atrial / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D006976:Hypertension, Pulmonary / Q000209:etiology*; D008168:Lung / Q000000981:diagnostic imaging*; D010477:Perfusion; D011652:Pulmonary Circulation; D011667:Pulmonary Veins / Q000002:abnormalities; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D013668:Technetium Tc 99m Aggregated Albumin
D019275:Radiopharmaceuticals; D013668:Technetium Tc 99m Aggregated Albumin