Normative values of 99mTc-MIBI distribution in myocardium in males and females, as a basis for quantitative planar scintigraphic method for detection of coronary artery disease in patients of both sexes.
BACKGROUND
Radionuclide perfusion studies of myocardium are being performed using planar and tomographic (SPECT) procedures. The latter method enables better detection as well as assessment of localisation and severity of scintigraphically visualised perfusion defects. On the other hand, lower cost of planar procedures using 99mTc-MIBI as the tracer and their much wider availability in countries of Central and Eastern Europe could significantly increase the diagnostic potential of nuclear cardiology in this region. The aim of the study was an assessment of normal distribution of 99mTc-MIBI in the myocardium and generation of normative basis for quantitative planar scintigraphic procedure, aiming at detection of CAD in patients of both sexes.


METHODS
The study was based on 250 patients. The reference (control) group consisted of 53 individuals (29 men, 24 women) with the low (< 10%) initial probability of CAD as estimated on basis of Diamond's tables. The second group included 197 patients (132 men, 65 women) with diagnosed CAD or with substantiated suspicion of its presence. In all patients of the latter group coronary angiography was performed and was used as the reference method for assessment of diagnostic efficacy of the scintigraphic procedure.


RESULTS
The original own method of acquired data evaluation was based on creation of circumferential profiles of activity and on using the procedure of trend-fitting for obtaining average curves and their dispersion around the mean values. The mean profile curves were obtained for three projections (anterior, LAO 45 degrees and LAO 70 degrees ). These mean curves differed significantly between both sexes. In LAO 45 degrees projection the differences affected mostly the region of the septum and postero-lateral wall of the left ventricle (LV). In LAO 70 degrees projection differences were most pronounced in the antero-septal wall of the LV.


CONCLUSIONS
Sensitivity, specificity and accuracy of CAD detection using the elaborated method, taking into account inter-sex differences, amounted to 86, 87 and 86% respectively in males, and correspondingly 81, 84 and 83% in females. The differences between corresponding indices for two sexes were statistically insignificant. For the whole group of patients the sensitivity, specificity and accuracy was 85, 86 and 85%, respectively.
Department of Nuclear Medicine, Medical University, Łódź, Poland.
J
J
Kuśmierek
A
A
Płachcińska