Nuclear Medicine: Planar Thallium Stress myocardial Imaging and False -Positive Test Results

Planar thallium stress myocardial imaging is a nuclear medicine diagnostic technique for predicting the presence of coronary artery disease.

Non-smoking hypertensive women in their forties with atypical chest pain have about a 10 % prevalence of significant coronary artery disease. This thallium stress test has a sensitivity of 80 % and a specificity of 90 % for coronary artery disease.


  1. What are the false-positive and false-negative rates for thallium stress tests as defined above?
  2. Determine the Predictive Value Negative for this test.


First some terminology:

  1. To find these rates it is helpful to draw a tree diagram:
  2. This is an application of Bayes’ Rule, a theorem of probability, which can be used to revise the probability a patient does or does not have the disease based on additional information being introduced ... in this case, a positive or negative result on a this test.

    If the test results are negative, then there is now a 98 % chance that the woman does not actually have the disease. This is a revision of the original probabilities based on the information given by the test.

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Written by Louise Routledge, Tuesday, June 24, 1997