Clinical relevance of left ventricular volumes and function assessed by gated SPECT in paediatric patients

Left ventricular (LV) end-diastolic and end-systolic volumes (EDV, ESV) and ejection fraction (EF) can be measured by echocardiography and gated single photon emission computed tomography (G-SPECT). The literature is rich in works on G-SPECT in adults, but lacks data for children. This work evaluates the accuracy of G-SPECT in children, compared to echocardiography.

The study comprised 60 children. Eighteen with history of sickle cell disease, 5 dilated cardiomyopathy, 12 valvular heart disease and one with hyperlipidaemia. Other 24 children free from cardiac problems were included. All patients were given 185-370 MBq (5-10 mCi) of 99mTc-MIBI or 99mTc-Myoview. Resting G-SPECT was acquired 45-60 min after injection. LV volumes and EF were measured by G-SPECT and echocardiography.

In all 60 cases, the correlation coefficients between both methods were 0.66 for EDV, 0.73 for ESV and 0.42 for EF. The 36 diseased children yielded fair to weak correlations for EDV, ESV and EF (r = 0.69, 0.74 and 0.41 respectively). The EDV was larger by echocardiography than G-SPECT (81.95 +/- 28.87 vs. 65.91 +/- 31.59 ml, p < 0.01). The ESV was also larger by echocardiography (39.13 +/- 15.96 vs. 23.44 +/- 18.04 ml, p < 0.01). The EF by G-SPECT (67.32 +/- 11.63%) was higher than by echocardiography (52.65 +/- 11.77%), (p < 0.01). The 24 normal subjects yielded almost the same level of weak correlation between both methods for EDV, ESV and EF (r = 0.59, 0.69, and 0.44 respectively).

LV volumes and EF computed by G-SPECT correlated poorly with echocardiography in small ventricles. Consequently, G-SPECT has a limited clinical usefulness in paediatrics.