What types of scans are associated with Tc MAA?

• A. Lung perfusion (PE), right to left cardiac shunt, liver/lung shunt mapping
• B. Kidney and bladder imaging
• C. Bone studies
• D. Brain imaging

Answer: (A)

The association of Technetium (Tc) labeled macroaggregated albumin (MAA) with lung perfusion scans is critical because MAA is specifically utilized in pulmonary perfusion imaging to assess blood flow in the lungs. In the case of a lung perfusion scan, a patient inhales or is injected with the Tc MAA, which then radiotracer aggregates get trapped in the pulmonary capillaries based on the perfusion of blood through the lungs. This imaging technique is vital for diagnosing conditions such as pulmonary embolism.

Additionally, Tc MAA can be instrumental in evaluating right-to-left cardiac shunts, where the aggregates can escape into the systemic circulation without passing through the lungs, which is a critical diagnostic element. The use of MAA in liver/lung shunt mapping further highlights its versatility in investigating vascular conditions beyond the lungs, providing a comprehensive assessment of shunt-related issues.

This choice accurately reflects the applications of Tc MAA in various imaging scenarios, central to pulmonary and shunt assessment in nuclear medicine. The other options pertain to different radiopharmaceuticals that do not utilize Tc MAA, correlating with distinct imaging studies unrelated to the perfusion and shunt functions that Tc MAA serves.