Abstract
A 56-yr-old man, two months after an operation for an acoustic neurinoma, gradually developed dyspnea. Massive pulmonary embolism (MPE), with a significant right-to-left (R-L) shunt, was seen in a perfusion scan of the lungs with Tc-99m MAA. Radioactivity was noted in the thyroid, spleen, kidneys and brain. A cardiac ultrasound study did not reveal intracardiac shunting. A few days later, when the patient’s condition improved, another perfusion scan of the lungs did not show the shunt, whereas a subsequent digital subtraction angiographic study confirmed the diagnosis of MPE but failed to reveal the cause of the shunt. In the absence of any possible pathophysiological mechanism, to explain the observed R-L shunt, we deduce that the particles of Tc-99m MAA might have passed through the precapillary pulmonary arteriovenous anastomoses and/or through dilated pulmonary capillaries, as a result of highly increased pulmonary vascular pressure due to MPE.
Similar content being viewed by others
References
Rosenbaum RC, Reiner BI, Bidwell JK, Johnston GS. Right-to-left shunting via persistent left superior vena cava identified by perfusion lung scintigraphy.J Nucl Med 30: 412–414, 1989.
Konstam MA, Levine BW, Strauss HW, McKusick KA. Left superior vena cava to left atrial communication diagnosed with radionuclide angiography and with differential right-to-left shunting.Am J Cardiol 43: 149–153, 1979.
Verzilbergen F, van Telling C, Plokker HW. Significance of the site of injection in unexpected right-to-left shunting.J Nucl Med 25: 1103–1105, 1984.
Brendel AJ, Larnaudie B, Lambert B, Leccia F, Barat JL, Dunasson D. Unsuccessful lung scan due to major right-to-left shunt through a sinus venous septal defect.J Nucl Med 26: 1029–1034, 1985.
Moyer JH, Glantz L, Brest AN. Pulmonary arteriovenous fistula.Am J Med 32: 417–435, 1962.
Kjoller E, Pedersen F, Svendsen TL, Sorensen SS. Microvascular right-to-left pulmonary shunt demonstrated by a radionuclide method.J Nucl Med 32: 139–140, 1991.
Rahimtoola SH, Kirklin JW, Burchell HB. Atrial septal defect.Circulation 37 (Suppl V): 2–12, 1968.
Mody MK, Karvelis KC, Pantelic MV. Scintigraphic demonstration of a right-to-left intracardiac shunt in a patient with massive pulmonary emboli.Clin Nucl Med 21: 368–370, 1996.
Moses CA. Right-to-left shunt on a lung scan.New Engl J Med 340: 857, 1999.
Datz FL.Handbook of Nuclear Medicine, Second Edition, Saint Louis, Mosby-Yearbook, p. 96, 1993.
Elliott CG. Pulmonary physiology during pulmonary embolism.Chest 101 (4 Suppl): 163S-171S, 1992.
West JB.Respiratory Physiology—The essentials, 3rd edition. Baltimore, Williams and Wilkins, pp. 31–40, 1985.
Wellman HN. Pulmonary thromboembolism: current status report on the role of nuclear medicine.Semin Nucl Med 16: 236–274, 1986.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Panoutsopoulos, G., Ilias, I. & Christakopoulou, I. Transient right-to-left shunt in massive pulmonary embolism. Ann Nucl Med 14, 217–221 (2000). https://doi.org/10.1007/BF02987863
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF02987863