ARDMS (American Registry for Diagnostic Medical Sonography) Practice Test

A sonographer has access to 10 MHz linear sequential, 7 MHz linear sequential, and 4.5 MHz curved array transducers. If the 10 MHz transducer produces aliasing during a carotid duplex study, what can be done to alleviate this issue if a shallower window did NOT correct the problem?

1. Switch to the 4.5 MHz curved array transducer.

2. Neither of the two remaining transducers will resolve this issue.

3. Switch to the 7 MHz linear sequential transducer.

4. None of these transducers should be used for carotid duplex exams.

The correct answer is: Switch to the 4.5 MHz curved array transducer.

Explanation In a carotid duplex study, the 10 MHz transducer may produce aliasing, which occurs when the speed of blood flow is higher than the chosen sampling frequency. This leads to incorrect representation of blood flow direction and may obscure important information. If switching to the 4.5 MHz curved array transducer does not alleviate this issue, it is recommended to switch to the 7 MHz linear sequential transducer instead. Option D, which suggests not using any of the transducers for carotid duplex exams, is incorrect as the 7 MHz transducer can still be effective in certain situations. Option B, stating that neither of the remaining transducers will work, is also incorrect as the 7 MHz transducer can provide a deeper view which may help alleviate the aliasing issue.