Improved visualization of perfusion defects by respiratory-gated SPECT: a phantom simulation study.

Area of Science:

• Nuclear Medicine
• Medical Imaging
• Diagnostic Radiology

Background:

• Single-photon emission computed tomography ventilation/perfusion (SPECT V/Q) imaging is crucial for diagnosing pulmonary embolism.
• Respiratory motion during SPECT imaging causes blurring and degrades image quality, potentially hindering accurate diagnosis.

Purpose of the Study:

• To investigate the effectiveness of respiratory gating and motion correction in improving SPECT lung imaging.
• To reduce image blur and enhance the definition of lung structures and defects.

Main Methods:

• Simulated pulmonary perfusion defects in an anthropomorphic lung phantom.
• Acquired gated and nongated SPECT images with simulated respiratory motion (10 and 20 cycles/min).
• Reconstructed images using ordered-subset expectation maximization and applied rigid motion correction; analyzed contrast and contrast-to-noise ratios (CNRs) using free-response receiver operating characteristic analysis.

Main Results:

• Respiratory motion significantly degraded the detectability of simulated lung defects.
• Motion-corrected gated SPECT images showed improved image quality, defect definition, and observer confidence.
• Quantification revealed significant increases in contrast and CNR after motion correction (P=0.0002).

Conclusions:

• Respiratory-gated, motion-corrected SPECT imaging enhances defect visualization compared to nongated images.
• This technique holds promise for improving the diagnostic accuracy of SPECT V/Q imaging, particularly for pulmonary embolism detection.