Contraindications and limitations may include the following:

• Inadequate acoustic windows and/or poor patient positioning
• Restless or uncooperative patients
• U.S. Food and Drug Administration (FDA) recommends the power output of the transducer be reduced to the lowest power that allows a complete orbital examination
• Remove contact lenses prior to the exam
• Output power must not exceed 10% of maximum emitted power or 17mW per cm2 or equivalent
• In emergent or critical care situations, it may be difficult to perform a complete exam
• TCD/TCDI performance during interventional procedures requires additional precautions for the examiner, due to the presence of radiation