Accuracy of 4 different algorithms for the analysis of tomographic radionuclide ventriculography using a physical, dynamic 4-chamber cardiac phantom.
Various automatic algorithms are now being developed to calculate left ventricular (LV) and right ventricular (RV) ejection fraction from tomographic radionuclide ventriculography. We tested the performance of 4 of these algorithms in estimating LV and RV volume and ejection fraction using a dynamic 4-chamber cardiac phantom.


METHODS
We developed a realistic physical, dynamic 4-chamber cardiac phantom and acquired 25 tomographic radionuclide ventriculography images within a wide range of end-diastolic volumes, end-systolic volumes, and stroke volumes. We assessed the ability of 4 algorithms (QBS, QUBE, 4D-MSPECT, and BP-SPECT) to calculate LV and RV volume and ejection fraction.


RESULTS
For the left ventricle, the correlations between reference and estimated volumes (0.93, 0.93, 0.96, and 0.93 for QBS, QUBE, 4D-MSPECT, and BP-SPECT, respectively; all with P < 0.001) and ejection fractions (0.90, 0.93, 0.88, and 0.92, respectively; all with P < 0.001) were good, although all algorithms underestimated the volumes (mean difference [+/-2 SDs] from Bland-Altman analysis: -39.83 +/- 43.12 mL, -33.39 +/- 38.12 mL, -33.29 +/- 40.70 mL, and -16.61 +/- 39.64 mL, respectively). The underestimation by QBS, QUBE, and 4D-MSPECT was greater for higher volumes. QBS, QUBE, and BP-SPECT could also be tested for the right ventricle. Correlations were good for the volumes (0.93, 0.95, and 0.97 for QBS, QUBE, and BP-SPECT, respectively; all with P < 0.001). In terms of absolute volume estimation, the mean differences (+/-2 SDs) from Bland-Altman analysis were -41.28 +/- 43.66 mL, 11.13 +/- 49.26 mL, and -13.11 +/- 28.20 mL, respectively. Calculation of RV ejection fraction correlated well with true values (0.84, 0.92, and 0.94, respectively; all with P < 0.001), although an overestimation was seen for higher ejection fractions.


CONCLUSIONS
Calculation of LV and RV ejection fraction based on tomographic radionuclide ventriculography was accurate for all tested algorithms. All algorithms underestimated LV volume; estimation of RV volume seemed more difficult, with different results for each algorithm. The more irregular shape and inclusion of a relatively hypokinetic RV outflow tract in the right ventricle seemed to cause the greater difficulty with delineation of the right ventricle, compared with the left ventricle.
De Bondt
Pieter
P
Division of Nuclear Medicine, P7, Ghent University Hospital, 9000 Ghent, Belgium. pdebondt@skynet.be
Claessens
Tom
T
Rys
Bart
B
De Winter
Olivier
O
Vandenberghe
Stijn
S
Segers
Patrick
P
Verdonck
Pascal
P
Dierckx
Rudi Andre
RA
D000465:Algorithms; D002306:Cardiac Volume; D006352:Heart Ventricles / Q000000981:diagnostic imaging; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000295:instrumentation / Q000379:methods*; D019047:Phantoms, Imaging; D015635:Radionuclide Ventriculography / Q000295:instrumentation / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012986:Software Validation; D013318:Stroke Volume; D015899:Tomography, Emission-Computed, Single-Photon / Q000295:instrumentation / Q000379:methods; D016276:Ventricular Function; D016277:Ventricular Function, Left / Q000502:physiology*; D016278:Ventricular Function, Right / Q000502:physiology*