Evaluating the effectiveness of a single CT method for attenuation correction in stress-rest myocardial perfusion...

This study aimed to evaluate the effectiveness of a single computed tomography (CT) based attenuation correction method using thallium-201 chloride (²⁰¹TlCl) in stress-rest myocardial perfusion imaging (MPI). The data of 106 patients who underwent MPI with single photon emission computed tomography (SPECT) using ²⁰¹TlCl were retrospectively reviewed. MPI SPECT images were reconstructed using stress SPECT and stress CT (SI_O), rest SPECT and rest CT (RI_O), and rest SPECT and stress CT (RI_A). The accuracy of alignment between the SPECT and CT images was evaluated with normalized cross-correlation (NCC) and visual examination. The summed rest score (SRS) was used to evaluate hypoperfusion at rest; washout rate (WO) was used to assess ischemia; and left ventricular ejection fraction (LVEF) was used to evaluate the left ventricle (LV) function. There was no significant difference in NCC and visual evaluation in all three dimensions. The SRS of both RI_O and RI_A (7.5 ± 7.7 and 7.7 ± 7.6, respectively) did not differ significantly. However, SRSs of RI_O and RI_A showed a strong correlation (r = 0.98). The WO was 39.0 ± 0.98% for both RI_O and RI_A, with a strong correlation between the two values (r = 1.00). LVEF was 61.1 ± 17.4% for RI_O and 61.3 ± 17.4% for RI_A, and a strong correlation was observed between the two values (r = 1.00). In conclusion, the single CT-based attenuation correction method with ²⁰¹TlCl SPECT has an accuracy equivalent to that of the conventional two CT-based attenuation correction method.