The interpolated projection data estimation method improves the image quality of myocardial perfusion SPECT with a short acquisition time

Objective: The interpolated projection data estimation processing (IPDE) method increases the amount of projection data by interpolation of the projection data. We examined the usefulness of the IPDE method for ²⁰¹Tl myocardial perfusion imaging (MPI) single photon emission computed tomography (SPECT) with a short acquisition time. Methods: Forty patients with suspected ischemic heart disease underwent stress ²⁰¹Tl-MPI SPECT. Both stress and delayed images were acquired with 4 cycles of 360° continuous rotation with a 90-direction setting for 14 min. The projection data used for reconstruction were 1) all cycle data (Tl-90-14min), 2) 2 cycles of data (Tl-90-7min), and 3) 2 cycles of data processed using the IPDE method (Tl-180IPDE-7min). This study compared the detection of the perfusion defect by the uptake score and the image quality of ²⁰¹Tl-MPI SPECT using the normalized mean square error (NMSE). Results: The uptake score of Tl-180IPDE-7min was significantly more concordant with Tl-90-14min in comparison to the Tl-90-7min (p < 0.05). The NMSE of the Tl-180IPDE-7min (1.85 ± 1.06%) was significantly lower than that of the Tl-90-7min (2.07 ± 1.24%) (p < 0.05). The degree of improvement by the IPDE method was significantly greater for the delayed ²⁰¹Tl-MPI SPECT than for the stress ²⁰¹Tl-MPI SPECT (p < 0.05). Conclusion: The IPDE method improved the image quality and secured the diagnostic ability of ²⁰¹Tl-MPI SPECT for a short acquisition time. Furthermore, the IPDE method is a simple software program that does not require any expensive equipment or use advanced algorithms. These results suggest that the IPDE method may be useful as an adjunctive method for shortening the acquisition time of ²⁰¹Tl-MPI SPECT.