nuclear stress test - decreased perfusion

Results of cardiology tests:

Clinically positive and electrically negative Bruce protocol exercise treadmill test. Fair exercise tolerance. Test stopped due to dyspnea. Chest pressure at peak exercise. Occasional PVCs. No ischemia.

A nuclear stress (only) test showed decreased perfusion in the anterior and inferolateral walls. ECG gated LV wall motion study revealed normal wall motion, normal wall thickening, normal systolic function, with a calculated ejection fraction of 58%.

Catheterization revealed no significant coronary artery stenosis, but mild aneurysmal changes, and normal left ventricular systolic function.

Since there is no evidence of stenosis, what might be causing the decreased perfusion?

[kenkeith]

"decreased perfusion in the anterior and inferolateral walls."

Almost always indicates some vessel occlusion from plague at location described. "No significant coronary artery strenosis".  The lumen (inside channel) size is normal.  If there were stenosis that could be the result of soft plaque (plaque within the artery lining) that narrows the the lumen, congenitally narrow, aneurysm, etc.