Development of a simple non-invasive microsphere quantification method for cerebral blood flow using I-123-IMP

Area of Science:

• Nuclear Medicine
• Cerebrovascular Imaging
• Quantitative SPECT

Background:

• Cerebral blood flow (CBF) measurement is crucial in clinical practice.
• Current methods like I-123-IMP SPECT with microsphere (MS) technique require invasive arterial blood sampling.
• Existing non-invasive methods lack the accuracy of the MS method, necessitating a simpler, accurate alternative.

Purpose of the Study:

• To develop a simple, non-invasive quantification method for I-123-IMP SPECT.
• To establish a simplified input function protocol based on the MS method.
• To enable routine clinical application of accurate CBF measurement.

Main Methods:

• Developed the Simple Input function-determining Method for SPECT (SIMS) method.
• Determined the input function using administered dose and integrated lung washout ratio from dynamic chest SPECT.
• Compared SIMS-derived mean CBF (mCBF) and input function with the MS method in 80 patients.

Main Results:

• High correlation between MS method arterial blood counts and SIMS estimated counts (r = 0.94, p < 0.01).
• Strong agreement between mCBF values obtained by MS and SIMS methods (r = 0.83, p < 0.01).
• SIMS method demonstrated high accuracy and reliability.

Conclusions:

• The SIMS method provides mCBF values consistent with the gold-standard MS method.
• This non-invasive technique shows potential for routine clinical use in SPECT imaging.
• SIMS offers a practical alternative for accurate quantitative CBF assessment.