Purpose: A retrospect study was done to determine the clinical utility of low-resolution X-ray CT attached to a gamma camera, utilizing its X-ray CT in attenuation correction (AC) of myocardial SPECT and comparing it with non-correction (NC) SPECT images and also with the coronary angiography (CAG) results which is considered as the gold standard for coronary artery disease (CAD).
Methods: We retrospectively reviewed the myocardial SPECT images of the 1920 continuous patients from May 2007 to April 2008 (1,209 men, 711 women; mean age 63 years) referred for suspected CAD. These patients had sequential myocardial SPECT imaging and CT. The myocardial perfusion imaging was done with 74 MBq (2 mCi) 201Tl under a standard dipyridamole pharmacological stress protocol. Visual interpretation revealed 29% (557 out of 1,920) and 41% (787 out of 1,920) were positive for CAD in AC and NC SPECT images, respectively. Based on the positive clinical interpretation of AC SPECT images, 224 men and 132 women of the 356 patients (with a total of 484 coronary territory lesions) had received CAG within 2 months after SPECT imaging. We compared the accuracy of AC and NC SPECT images with the coronary angiography (CAG).
Results: Visual assessment resulted in improvements of overall diagnostic accuracy (sensitivity/specificity/accuracy were 81%/86%/85% and 79%/74%/76%, respectively, for AC and NC images) with CAG as the gold standard for CAD.
Conclusion: The accuracy and specifically the specificity were increased on AC images. These preliminary data suggest that X-ray CT based AC of hybrid SPECT/CT in myocardial SPECT imaging has the potential to develop into a preferred standard clinical technique in nuclear medicine myocardial perfusion imaging.