Assessment of left ventricular volumes; reliable by gated SPECT?

Assessment of cardiac function continues to be an important issue in patients with assumed left ventricular dysfunction [1][2][3][4][5][6][7][8][9][10].In particular in patients with enlarged left ventricles, such as occurs in ischemic and idiopathic dilated cardiomyopathy, accurate assessment of left ventricular function remains pivotal [11][12][13][14].To assess myocardial function, different diagnostic methods are currently performed, such as MRI, SPECT,.In the clinical arena, detection of myocardial function is predominantly based on echocardiographic studies.However, nuclear techniques, showing preserved tracer uptake and metabolism in viable myocardium, may also assess left ventricular function and wall motion.Analysis by gated SPECT imaging offers considerable additional value to SPECT myocardial perfusion imaging in characterizing functional abnormalities thereby potentially improving test specificity [24][25][26][27][28][29][30].Preserved wall motion and/or thickening in region with perfusion defects might denote remaining viability indicating potentially well functioning myocardium [31][32][33][34][35][36].By assessing left ventricular volumes the application of gated SPECT influences the appropriate management strategy.Since myocardial perfusion, function and wall motion/thickening can be assessed simultaneously, gated SPECT imaging follows the concept of a one-stop shop such as propagated by MRI studies [37][38][39][40][41].However, MRI may be more accurate than gated SPECT in establishing left ventricular parameters because of its superb spatial resolution [20,[42][43][44][45][46][47][48][49].In the current issue of the International Journal of Cardiovascular Imaging, Sipola et al. [50] prospectively compared left ventricular end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (LVEF) both by gated SPECT and cardiac MRI in 21 patients with idiopathic dilated cardiomyopathy.All 21 patients underwent both 99 mTctetrofosmin gated SPECT imaging and MRI within a 3 h interval.Close linear correlations were observed between both methods in left ventricular EDV and left ventricular ESV but correlations were significantly weaker for LVEF.Left ventricular EDV and left ventricular ESV were smaller for gated SPECT than for MRI.In 4 patients (21%) the left ventricular EDV index was considered normal by gated SPECT and increased by MRI, if MRI-derived normal values were used.No differences were found between gated SPECT and MRI when MRI-determined LVEF was below 40%.However, gated SPECT showed smaller LVEF when MRI-determined LVEF was over 40%.The authors concluded that an increased left ventricular EDV in gated SPECT is reliable compared with