Twenty patients were studied by equilibrium radionuclide angiography (RNA) twice in the same day in order to assess the repeatability of quantitative measurements of left ventricular (LV) regional function by using a sector analysis method. RNA was performed in the best septal 45° left anterior oblique projection, acquiring 150,000 counts/frame, at 20 msec/frame with 5% gate tolerance. LV regional analysis was performed using a computer algorithm written by the authors running on Digital PDP 11/34 machine. The algorithm after having identified the center of gravity of the LV, divided it into 4, 5 and 6 equiangular sectors. In the 5, and 6 sector analysis, the region including the mitral and aortic valves was excluded from subsequent analysis. In each sector Ejection Fraction (EF) and Peak Filling Rate (PFR) were computed. In addition, the Time to End Systole (TES) and Time to Peak Filling Rate were also assessed for each region. The coefficient of variation of the regional values of TES (CV-TES) and regional TPFR (CV-TPFR) were then computed and considered as indices of LV systolic (CV-TES) and diastolic (CV-TPFR) asynchrony. Repeatability was firstly assessed by linear regression analysis between the 2 RNA studies. Our data show a high correlation coefficient on regional values of EF and PFR (R: > 0.92). Moreover, the differences in a given parameter between the 2 studies were plotted against their mean value, and the coefficient of repeatability (CR) was calculated as twice the standard deviation of the differences. No significant differences were found between EF and PFR regional values in the 2 RNA studies (EF coefficient of repeatability: <0.18; PFR coefficient of repeatability: <0.8). A low value of coefficient of repeatability was found also for CV-TES (<17) and for CV-TPFR (<18). In conclusion LV regional analysis is a repeatable method of analysis, and the number of regions does not affect the repeatability.
ASJC Scopus subject areas
- Cancer Research
- Molecular Medicine
- Radiology Nuclear Medicine and imaging