Pinhole SPECT imaging in normal and morbid ankles

Area of Science:

• Nuclear Medicine
• Medical Imaging
• Orthopedics

Background:

• Traditional planar SPECT offers limited resolution for detailed ankle and hindfoot imaging.
• Accurate visualization of anatomical landmarks and pathological alterations is crucial for diagnosing foot and ankle conditions.

Purpose of the Study:

• To evaluate the enhanced resolution of pinhole SPECT for ankle and hindfoot imaging.
• To assess the clinical utility of pinhole SPECT in diagnosing various ankle pathologies.

Main Methods:

• Pinhole SPECT was performed using a single-head gamma camera with a pinhole collimator, replacing the standard parallel-hole collimator.
• Image reconstruction utilized the filtered back-projection algorithm with a Butterworth filter.
• Resolution was compared between planar and pinhole SPECT using a thyroid phantom and normal ankle/hindfoot, with CT validation. Clinical utility was assessed in cases of fracture, reflex sympathetic dystrophy syndrome, and rheumatoid arthritis.

Main Results:

• Pinhole SPECT demonstrated significantly enhanced resolution compared to planar SPECT for both phantom and normal ankle/hindfoot imaging.
• While peripheral image distortion was observed, pinhole SPECT clearly delineated most anatomical landmarks in the ankle and hindfoot.
• Diagnostic signs in diseased ankles, such as fractures and signs of inflammation in rheumatoid arthritis, were visible.

Conclusions:

• Pinhole SPECT, adaptable to standard gamma camera systems, yields sectional ankle and hindfoot images with superior resolution.
• The technique effectively portrays anatomical details and pathological findings, offering valuable diagnostic information for both normal and morbid conditions.
• Pinhole SPECT represents an advancement in nuclear imaging for detailed assessment of the ankle and hindfoot.