ABSTRACT
OBJECTIVES: This study describes the practical implementation of X-ray-based attenuation correction (AC) of myocardial perfusion scans in a large teaching hospital, characterizes the impact of AC on the diagnostic confidence of the interpreter and tries to predict which patients are likely to benefit from the technique. METHODS: One hundred and seven consecutive patients underwent a 2 day (99m)Tc-tetrofosmin protocol with adenosine stress using GE Millennium VG with AC and ECG-gated acquisition (ECG-g). The diagnostic impact of AC/ECG-g was judged by a panel of three observers. RESULTS: AC was not achieved in 46 patients. Individual observers rated AC 'essential' in 37 scans and 'helpful' in 68 scans. For ECG-g, this applied to 12 and 78 scans, respectively. The rating for AC was better than that for ECG-g in 57 scans, and vice versa in 31 scans. Equal ratings were recorded in 41 scans, and neither technique was needed in 54 scans. Diagnostic interpretation of abnormal scans was significantly more likely to benefit from either AC or ECG-g than interpretation of normal scans. Patients in whom AC was considered useful had a significantly higher body mass and chest circumference, but the overlap was large. CONCLUSIONS: In practice, AC was not feasible in a significant proportion of our patients. AC received better ratings from observers more often than ECG-g. Interpreter confidence with AC was significantly greater in scans with perfusion defects than in normal scans. Body mass and chest circumference cannot be used to predict which patients will benefit from AC.
