A Study Is Conducted to Assess Myocardial Perfusion Imaging Performance

question 457

Multiple Choice

A study is conducted to assess myocardial perfusion imaging performance using a new pharmacologic agent for stress testing.  The test is performed on inpatients and outpatients with chest pain.  Patients with positive stress test results underwent cardiac catheterization to diagnose flow-limiting coronary artery disease (CAD) .  Physicians interpreting the catheterization radiographs were blinded to inpatient/outpatient status.  The following results are obtained: Inpatients:
Number of patients with positive stress test: 122
Flow-limiting CAD on cardiac catheterization: 102/122 (84%)
Outpatients:
Number of patients with positive stress test: 115
Flow-limiting CAD on cardiac catheterization: 67/115 (58%)
Which of the following best explains the difference in the rate of flow-limiting CAD between the groups in this study?

• A)Blinding of the catheterization film readers
• B)Negative likelihood ratio of the test
• C)Prevalence of the disease in the patient groups
• D)Positive likelihood ratio of the test
• E)Sensitivity of the test

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Definitions:

Standard Deviation

A metric that quantifies the degree to which values in a collection vary from the average value of the group.

IQR

The interquartile range, a measure of statistical variability between the 25th and 75th percentiles.

Range

The difference between the highest and lowest values in a dataset, providing a measure of the data's dispersion.

Standard Deviation

An indicator calculating the spread of data around the mean, achieved by the square root of the variance.