Thallium stress test

A relative of mine had a Thallium stress test done and was told that the test revealed that he had some blockage on the lower right side of his heart. The doctor did not do a catherization but told my relative that he probably had perhaps a 10% blockage. My relative is very active (although over weight) 40 years old and has no chest pain during activities such as mowing grass etc. He has a family history of heart disease on his fathers side also. My question to you is...How could an insignificant amount of blockage show up on his Thallium stress test, yet the Heart Forum states that a small amount of blockage will not show up on the Thallium stress test. Could a blockage of 10 or 20 percent be revealed on this stress test?

[CCF CARDIO MD - DLB]

A 10-20% blockage of a particular coronary artery would not show up on a Thallium stress test.

[Rodney Cirello]

I beg to differ with you doctor.....but my mother had a Thallium stress test done about 5 years ago and it showed some blockage. A catherization was performed and it showed a blockage of 25% percent. According to you, this is impossible because the Thallium stress test doesn't detect "small" blockages. As the saying goes "The proof of the pudding is in the tasting". In my mothers case, the proof that the Thallium stress test detected a "minor" blockage was the follow uo catherization. Perhaps you should get a new gamma machine which performs better...like the one that was used on my mother! According to the Heart Forum, there is no test that can detect any significant blockages short of the catherization. A person could go on for years with heart disease and not even know it until the pain starts. Thats a sad state of affairs in you ask me. There has to be a better way!

[CCF CARDIO MD - DLB]

Half a knowledge is a dangerous thing, and that is exactly what you have provided. The 25% blockage did not cause the abnormality in the Thallium scan, but was just incidental to it. You should not speak so authoritatively about topics that you know nothing about.