Images of pulmanary perfusion scintigraphy
View main image(pe) in a separate image viewer
View second image(pe). Pulmanary perfusion scintigraphy - spot views
View third image(xr). Chest radiograph
View fourth image(pe). Quntitative activity of whole body and lungs (lower data are lungs vs the rest of the imaged body)
Full history/Diagnosis is available below
The perfusion images show diffusely decreased activity in the left lung, with slightly more prominent activity in the left lung base.
The right lung receives 65% and the left lung receives 35% of total pulmonary perfusion.
Analysis of the global pulmonary activity as compared to the systemic activity demonstrates approximately 60% of activity in the lung and approximately 40% in the remainder of the visualized portions of the body. The findings are consistent with a marked right-to-left shunt.
The presence of extrapulmonary activity on perfusion scintigraphy indicates the presence of free Tc-99m pertechnetate or an intra- or extracardiac right-to-left shunt. In a right-to-left shunt, the radiopharmaceutical will accumulate in the systemic capillary beds, primarily the kidneys, brain, and spleen. In contrast, free Tc-99m pertechnate will accumulate most prominently in the stomach, thyroid, salivary glands, and kidneys. An image of the head is the most definitive way to distinguish between a right-to-left shunt and free Tc-99m pertechnetate because intracerebral activity is present with a shunt but not when there is free Tc-99m pertechnetate.
Normal patients should have more than 90% of radioactivity in the lungs. Pulmonary accumulation of Tc-99m MAA drops as a function of time and become less than 90% after 30 min because of breakdown of the MAA. Timing is thus importnat in evaluating a shunt.
Absolute quantification, including the pulmonary to systemic perfusion ratio (Qp/Qs) is possible, but was not completely done in the case because the entire body was not imaged.
1. Hosono M, Machida K, Honda N. Quantitative lung perfusion scintigraphy and detection of intrapulmonary shunt in liver cirrhosis. Annals of Nuclear Medicine. 2002; Vol. 16, No. 8, 577–581.
2. Gang L, Wei-jen S, Chou C, et a. Tc-99m MAA Total-Body Imaging to Detect Intrapulmonary Right-to-Left Shunts and to Evaluate the Therapeutic Effect in Pulmonary Arteriovenous Shunts. Clinical Nuclear Medicine. 1996; 21(3):197-202.
3. Verttukattil JJ, et al. Radionuclide investigation of congenital heart disease. Heart 2000;84:467-468.
4. MIR Teaching file case vq026.
5. Ziessman HA, Rehm P. Case review: nuclear medicine. Mosby, Inc. 2002.
References and General Discussion of Perfusion (only) Scintigraphy (Anatomic field:Lung, Mediastinum, and Pleura, Category:Normal, Technique, Congenital Anomaly)
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