Unexpected occurrence of right to left shunt during lung perfusion scintigraphy: a problem-based learning exercise


  • James Edward Goodhind Elliott Canterbury Christ Church University Maidstone and Tunbridge Wells NHS Trust https://orcid.org/0000-0003-3122-6275
  • Luisa Roldao Pereira Maidstone and Tunbridge Wells NHS Trust


VQ scan, 99mTc-MAA, nuclear medicine practitioner


This case report presents a problem-based learning exercise that occurred during lung perfusion scintigraphy with technetium-99m macroaggregated albumin (99mTc-MAA) with the incidental finding of a previously undiagnosed right-to-left shunt. The pathology manifested with a redirection of 99mTc-MAA-loaded blood into systemic circulation and subsequent uptake in gastric, renal, and thyroid tissues. Incorrect radiopharmaceutical administration, radiopharmacy error and independent constituents of 99mTc-MAA offered alternative explanations which required exclusion. Subsequent recommendations included diligent use of safety procedures and appropriate documentation during receiving, dispensing and administration of radiopharmaceuticals. Clinical suspicion of RLS may warrant additional 99mTc-MAA imaging to confirm diagnosis or quantify severity.


Lay abstract

This case report provides an illustrated example of problem-based learning during a nuclear medicine lung imaging scan. The unexpected distribution of radioactivity within the stomach, kidneys and thyroid tissues required the attending nuclear medicine staff to provide a revised diagnosis of right-to-left cardiac shunt.

Author Biographies

James Edward Goodhind Elliott, Canterbury Christ Church University Maidstone and Tunbridge Wells NHS Trust

Lecturer in diagnostic radiography at Canterbury Christ Church University.

Senior radiographer at Maidstone Nuclear Medicine department, Maidstone and Tunbridge Wells NHS Trust (Kent, United Kingdom).

Luisa Roldao Pereira, Maidstone and Tunbridge Wells NHS Trust

Therapy Lead and Advanced Practitioner in Nuclear Medicine Physics

Maidstone Nuclear Medicine department.






Case Reports