Question:
A 73 year old male was referred to our laboratory for a Myoview exercise stress test.
He had no prior history of CAD, but presented with persistent atrial fib/flutter over a
period of 3 years, with multiple unsuccessful cardioversion attempts.
The reconstructed stress and rest SPECT images are shown below.

What is your interpretation?

(Image 1)

Answer:

If you said that there is an irregular perfusion uptake pattern with a large severe mid to
distal lateral wall and apical myocardial infarction, then you're wrong. If you said that we
reconstructed the region of 99mTc-Tetrofosmin uptake superior to the LV myocardium,
you're right.

The properly reconstructed images of the myocardium are normal as seen below.
(Image 2)

This was a case of incidental finding of extracardiac uptake of 99mTc-Tetrofosmin recognized
and reported by our staff. Referring physician was recommended to order a CT scan.

CT findings confirmed a large 11cm. X 8cm. mass with mixed attenuation that was located in
the prevascular space of the anterior mediastinum just above the level of the left atrium and
most likely consistent with carcinoma.

Surgical biopsy revealed a largely encapsulated atypical thymoma, predominantly composed
of epithelial and spindle cell type with large areas of central necrosis.

After successful resection of the tumor, patient returned to normal sinus rhythm.

Technologists should always be on the lookout for extracardiac uptake of tracer substances as
this can lead to incidental finding of potentially malignant tumors.