Segmentation of gated Tl-SPECT images for automatic computation of myocardial volume and ejection fraction

The authors present an algorithm for automatic assessment of left ventricular ejection fraction (EF) and absolute volume from gated Thallium-SPECT myocardial perfusion images. The system consists of two independent blocs for segmentation and computation of function. The authors introduce a novel formulation for computation of EF based on the epi-cardial contour. The algorithm was validated against manual border tracing from two physicians on different modalities, and gave consistent linear agreement. PET manual vs. Automatic-avg. r=0.91, Tl-SPECT manual vs. auto-r=0.79. The new epicardial method was compared to performance at. High noise. Finally, preliminary comparison were made of EFs computed for PET, ^99mTc-SPECT and ²⁰¹Tl-SPECT to those obtained from planar gated blood pool imaging (GBP) yielding good results. The proposed scheme is specifically designed for ²⁰¹Tl-SPECT, but may be used on other image modalities as well. It permits EF computation on relatively noisy images without the need for additional image acquisitions