Evaluating the effectiveness of a single CT method for attenuation correction in stress-rest myocardial perfusion imaging with thallium-201 chloride SPECT.

This study aimed to evaluate the effectiveness of a single computed tomography (CT) based attenuation correction method using thallium-201 chloride ( 201 TlCl) in stress-rest myocardial perfusion imaging (MPI). The data of 106 patients who underwent MPI with single photon emission computed tomography (SPECT) using 201 TlCl 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 201 TlCl SPECT has an accuracy equivalent to that of the conventional two CT-based attenuation correction method.