Computer-generated attenuation correction does not improve the accuracy of myocardial perfusion scintigraphy.

A short study was performed to determine if it is possible to increase the accuracy of thallium-201 (201T1) single photon emission tomographic myocardial perfusion imaging using computer-generated ('Chang') attenuation correction. The stress and rest myocardial perfusion studies from 22 patients with suspected or known ischaemic heart disease were reconstructed with and without "Chang' attenuation correction. For all patients, the scintigraphy results were compared with those of coronary angiography. Attenuation correction improved the accuracy of 201T1 myocardial perfusion imaging for defining myocardial ischaemia or infarction in 8% of coronary artery territories (23% of patients), but it was worse in 5% of coronary artery territories (14% of patients). These changes were not significant (McNemar's test). Therefore, computer-generated 'Chang' attenuation correction does not appear to improve the accuracy of myocardial perfusion scintigraphy. It is important that all techniques suggested to improve the accuracy of clinical images should be tested on patients before being widely used.