One-day protocol for cerebral perfusion reserve with acetazolamide

Area of Science:

• Nuclear Medicine
• Cerebrovascular Imaging
• Radiopharmaceuticals

Background:

• Assessing cerebral perfusion reserve is crucial for diagnosing and managing cerebrovascular diseases.
• Existing methods for measuring cerebral perfusion reserve can be time-consuming and complex.

Purpose of the Study:

• To introduce and evaluate a novel one-day protocol for cerebral perfusion reserve assessment using a double injection of 99mTc-ECD.
• To determine the feasibility and effectiveness of this simplified protocol.

Main Methods:

• Thirty subjects underwent two sequential brain perfusion studies with 99mTc-ECD (370 MBq then 740 MBq) and dynamic SPECT scans.
• Acetazolamide (ACZ) was administered to 23 subjects to assess cerebrovascular reactivity.
• Washout rates, regional count increases, and inter-hemispheric differences were calculated to evaluate the protocol's performance and reproducibility.

Main Results:

• The 99mTc-ECD washout rate was minimal and unaffected by ACZ administration within the first 50 minutes.
• The protocol demonstrated excellent reproducibility (r = 0.997).
• ACZ administration significantly increased cerebral perfusion in normal brain regions compared to affected regions in patients with cerebrovascular disease, highlighting its utility in detecting perfusion deficits.

Conclusions:

• The developed one-day double-injection 99mTc-ECD protocol is feasible and effective for assessing cerebral perfusion reserve.
• The minimal ECD washout and lack of ACZ interference support the protocol's validity.
• The procedure's simplicity and short duration make it a clinically valuable tool for evaluating cerebrovascular reactivity.