BACKGROUND. The aim of this study was to evaluate the impact of attenuation correction (AC) on the diagnostic accuracy of conventional stress/red thallium SPECT studies. METHODS. We studied 60 consecutive patients (36 males) who underwent conventional diagnostic stress/red study with and without AC (NAC) using a dual-head SPECT camera (Vertex ADAC) with a 153Gd source. The mean age of these patients was 60 years (30-80) and 29 of the subjects had a history of MI. Reconstructed images were visually analyzed using 20 segments scored on a 5-point scale (0 = normal, 4 = no uptake). Diagnostic accuracy was evaluated in 24 consecutive patients who underwent coronary angiography. Polar plots from each of the four reconstructed data sets per patient were normalized on the maximum and quantified using a nine segment model. RESULTS. The comparison between the segmental stress score obtained with and without AC showed agreement in 1057 out of 1200 (88%) segments analyzed, K statistic value = 0.67. The number of fixed defects was significantly lower after AC. The diagnostic accuracy, evaluated in 24 patients (480 sags), was not significantly different between AC and NAC analysis (80 vs 84% respectively). CONCLUSIONS. AC seems to reduce the number of fixed defects due to attenuation artefacts without improving diagnostic accuracy, probably because of the low number of subjects submitted to angiography and of the interpreting bias due to the expertise of the operators. In fact, in the rather small group of patients evaluated, no improvement in diagnostic accuracy was observed, probably because several attenuation defects were not considered pathological due to operator expertise.
|Titolo:||Comparison between TI-201 transmission-emission SPECT images, with and without attenuation correction in CAD patients [Confronto tra immagini SPECT trasmissive-emissive corrette per attenuazione e non corrette, ottenute con TI-201 in coronaropatici]|
|Parole Chiave:||Coronary heart diseases; Myocardial Scintigraphy; Thallium 201|
|Settore Scientifico Disciplinare:||Settore MED/36 - Diagnostica per Immagini e Radioterapia|
|Data di pubblicazione:||1999|
|Appare nelle tipologie:||01 - Articolo su periodico|