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The aim of this study was to investigate the value of a real-time magnetic resonance imaging (MRI) approach for the assessment of left-ventricular-wall motion in patients with insufficient transthoracic echocardiography in terms of accuracy and temporal expenditure. Twenty-five consecutive patients were examined on a 1.5-Tesla whole-body MR system (ACS-NT, Philips Medical Systems, Best, NL) using a real-time and ECG-gated (the current gold standard) steady-state free-precession (SSFP) sequence. Wall motion was analyzed by three observers by consensus interpretation. In addition, the preparation, scanning, and overall examination times were measured. The assessment of the wall motion demonstrated a close agreement between the two modalities resulting in a mean kappa coefficient of 0.8. At the same time, each stage of the examination was significantly shortened using the real-time MR approach. Real-time imaging allows for accurate assessment of left-ventricular-wall motion with the added benefit of decreased examination time. Therefore, it may serve as a cost-efficient alternative in patients with insufficient echocardiography.

We sought to assess the value of non-contrast enhanced transthoracic harmonic echocardiography (TEE) for the visualization of left ventricular thrombi in 34 patients with cardiomyopathy. Results were compared to contrast-enhanced magnetic resonance imaging as reference standard. Maximal thrombus size was quantified with both modalities. Magnetic resonance imaging demonstrated thrombi in 15 patients. In these subjects echocardiography was negative in seven patients. Thrombi were excluded in 19 patients with magnetic resonance while echocardiography was deemed positive in 5 subjects. Thrombus size by ce-CMR was not different for clots visualized or not visualized by echocardiography (P = 0.71). Moreover, observer agreement was superior for ce-CMR (kappa = 0.94) as compared to TTE (kappa= 0.71). Non-contrast-enhanced harmonic TTE has limited value for the visualization of thrombi in patients with cardiomyopathy.

The main aim of this study was to validate the accuracy of 4D-MSPECT in the assessment of left ventricular (LV) end-diastolic/end-systolic volumes (EDV, ESV) and ejection fraction (LVEF) from gated technetium-99m methoxyisobutylisonitrile single-photon emission tomography ((99m)Tc-MIBI SPET), using cardiac magnetic resonance imaging (cMRI) as the reference method. By further comparing 4D-MSPECT and QGS with cMRI, the software-specific characteristics were analysed to elucidate clinical applicability. Fifty-four patients with suspected or proven coronary artery disease (CAD) were examined with gated (99m)Tc-MIBI SPET (8 gates/cardiac cycle) about 60 min after tracer injection at rest. LV EDV, ESV and LVEF were calculated from gated (99m)Tc-MIBI SPET using 4D-MSPECT and QGS. On the same day, cMRI (20 gates/cardiac cycle) was performed, with LV EDV, ESV and LVEF calculated using Simpson's rule. Both algorithms worked with all data sets. Correlation between the results of gated (99m)Tc-MIBI SPET and cMRI was high for EDV [ R=0.89 (4D-MSPECT), R=0.92 (QGS)], ESV [ R=0.96 (4D-MSPECT), R=0.96 (QGS)] and LVEF [ R=0.89 (4D-MSPECT), R=0.90 (QGS)]. In contrast to ESV, EDV was significantly underestimated by 4D-MSPECT and QGS compared to cMRI [130+/-45 ml (4D-MSPECT), 122+/-41 ml (QGS), 139+/-36 ml (cMRI)]. For LVEF, 4D-MSPECT and cMRI revealed no significant differences, whereas QGS yielded significantly lower values than cMRI [57.5%+/-13.7% (4D-MSPECT), 52.2%+/-12.4% (QGS), 60.0%+/-15.8% (cMRI)]. In conclusion, agreement between gated (99m)Tc-MIBI SPET and cMRI is good across a wide range of clinically relevant LV volume and LVEF values assessed by 4D-MSPECT and QGS. However, algorithm-varying underestimation of LVEF should be accounted for in the clinical context and limits interchangeable use of software.

The segmentation algorithm ESM based on an elastic surface model was validated for the assessment of left ventricular volumes and ejection fraction from ECG-gated myocardial perfusion SPECT. Additionally, it was compared with the commercially available quantification packages 4D-MSPECT and QGS. Cardiac MRI was used as the reference method. SPECT and MRI were performed on 70 consecutive patients with suspected or proven coronary artery disease. End-diastolic (EDV) and end-systolic (ESV) volumes and left ventricular ejection fraction (LVEF) were derived from SPECT studies by using the segmentation algorithms ESM, 4D-MSPECT and QGS and from cardiac MRI. ESM-derived values for EDV and ESV correlated well with those from cardiac MRI (correlation coeffients R = 0.90 and R = 0.95, respectively), as did the measurements for LVEF (R = 0.86). Both EDV and ESV were slightly overestimated for larger ventricles but not for smaller ventricles; LVEF was slightly overestimated irrespective of ventricle size. The above correlation coefficients are comparable to those for the 4D-MSPECT and QGS segmentation algorithms. However, results obtained with the three segmentation algorithms are not interchangeable. The ESM algorithm can be used to assess EDV, ESV and LVEF from gated perfusion SPECT images. Overall, the performance was similar to that of 4D-MSPECT and QGS when compared with cardiac MRI. Results obtained with the three tested segmentation methods are not interchangeable, so that the same algorithm should be used for follow-up studies and control subjects.

The goal of this study was to validate the accuracy of the Emory Cardiac Tool Box (ECTB) in assessing left ventricular end-diastolic or end-systolic volume (EDV, ESV) and ejection fraction (LVEF) from gated (99m)Tc-methoxyisobutylisonitrile ((99m)Tc-MIBI) SPECT using cardiac MRI (cMRI) as a reference. Furthermore, software-specific characteristics of ECTB were analyzed in comparison with 4D-MSPECT and Quantitative Gated SPECT (QGS) results (all relative to cMRI).Seventy patients with suspected or known coronary artery disease were examined using gated (99m)Tc-MIBI SPECT (8 gates/cardiac cycle) 60 min after tracer injection at rest. EDV, ESV, and LVEF were calculated from gated (99m)Tc-MIBI SPECT using ECTB, 4D-MSPECT, and QGS. Directly before or after gated SPECT, cMRI (20 gates/cardiac cycle) was performed as a reference. EDV, ESV, and LVEF were calculated using Simpson's rule.Correlation between results of gated (99m)Tc-MIBI SPECT and cMRI was high for EDV (R = 0.90 [ECTB], R = 0.88 [4D-MSPECT], R = 0.92 [QGS]), ESV (R = 0.94 [ECTB], R = 0.96 [4D-MSPECT], R = 0.96 [QGS]), and LVEF (R = 0.85 [ECTB], R = 0.87 [4D-MSPECT], R = 0.89 [QGS]). EDV (ECTB) did not differ significantly from cMRI, whereas 4D-MSPECT and QGS underestimated EDV significantly compared with cMRI (mean +/- SD: 131 +/- 43 mL [ECTB], 127 +/- 42 mL [4D-MSPECT], 120 +/- 38 mL [QGS], 137 +/- 36 mL [cMRI]). For ESV, only ECTB yielded values that were significantly lower than cMRI. For LVEF, ECTB and 4D-MSPECT values did not differ significantly from cMRI, whereas QGS values were significantly lower than cMRI (mean +/- SD: 62.7% +/- 13.7% [ECTB], 59.0% +/- 12.7% [4DM-SPECT], 53.2% +/- 11.5% [QGS], 60.6% +/- 13.9% [cMRI]).EDV, ESV, and LVEF as determined by ECTB, 4D-MSPECT, and QGS from gated (99m)Tc-MIBI SPECT agree over a wide range of clinically relevant values with cMRI. Nevertheless, any algorithm-inherent over- or underestimation of volumes and LVEF should be accounted for and an interchangeable use of different software packages should be avoided.

Gated myocardial perfusion SPECT allows assessment of left ventricular end-diastolic volume (EDV), left ventricular end-systolic volume (ESV), left ventricular stroke volume (SV), and left ventricular ejection fraction (LVEF). Acquiring images with the patient both prone and supine is an approved method of identifying and reducing artifacts. Yet prone positioning alters physiologic conditions. This study investigated how prone versus supine patient positioning during gated SPECT affects EDV, ESV, SV, LVEF, and heart rate.Forty-eight patients scheduled for routine myocardial perfusion imaging were examined with gated (99m)Tc-sestamibi SPECT (at rest) while positioned prone and supine (consecutively, in random order). All parameters for both acquisitions were calculated using the commercially available QGS algorithm.Whereas EDV and SV were significantly lower (P0.0004) for prone acquisitions (EDV, 110.5 +/- 39.1 mL; SV, 55.9 +/- 13.3 mL) than for supine acquisitions (EDV, 116.9 +/- 36.2 mL; SV, 61.0 +/- 14.5 mL), ESV and LVEF did not differ significantly. Heart rate was significantly higher (P0.0001) during prone acquisitions (69.1 +/- 10.5 min(-1)) than during supine acquisitions (66.5 +/- 10.0 min(-1)).The observed position-dependent effect on EDV, SV, and heart rate might be explained by decreased arterial filling and increased sympathetic nerve activity. Hence, supine reference data should not be used to classify the results of prone acquisitions.

The aim of this study was to validate Quantitative Gated SPECT (QGS) and 4D-MSPECT for assessing left ventricular end-diastolic and systolic volumes (EDV and ESV, respectively) and left ventricular ejection fraction (LVEF) from gated (18)F-FDG PET.Forty-four patients with severe coronary artery disease were examined with gated (18)F-FDG PET (8 gates per cardiac cycle). EDV, ESV, and LVEF were calculated from gated (18)F-FDG PET using QGS and 4D-MSPECT. Within 2 d (median), cardiovascular cine MRI (cMRI) (20 gates per cardiac cycle) was done as a reference.QGS failed to accurately detect myocardial borders in 1 patient; 4D-MSPECT, in 2 patients. For the remaining 42 patients, correlation between the results of gated (18)F-FDG PET and cMRI was high for EDV (R = 0.94 for QGS and 0.94 for 4D-MSPECT), ESV (R = 0.95 for QGS and 0.95 for 4D-MSPECT), and LVEF (R = 0.94 for QGS and 0.90 for 4D-MSPECT). QGS significantly (P0.0001) underestimated LVEF, whereas no other parameter differed significantly between gated (18)F-FDG PET and cMRI for either algorithm.Despite small systematic differences that, among other aspects, limit interchangeability, agreement between gated (18)F-FDG PET and cMRI is good across a wide range of clinically relevant volumes and LVEF values assessed by QGS and 4D-MSPECT.

The aim of this study was to validate the estimation of left ventricular end-diastolic and end-systolic volumes (EDV, ESV) and ejection fraction (LVEF) as well as wall motion analysis from gated fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) in patients with severe coronary artery disease (CAD) using software originally designed for gated single-photon emission tomography (SPET). Thirty patients with severe CAD referred for myocardial viability diagnostics were investigated using a standard FDG PET protocol enhanced with gated acquisition (8 gates per cardiac cycle). EDV, ESV and LVEF were calculated using standard software designed for gated SPET (QGS). Wall motion was analysed using a visual four-point wall motion score on a 17-segment model. As a reference, all patients were also examined within a median of 3 days with cardiovascular cine magnetic resonance imaging (cMRI) (20 gates per cardiac cycle). Furthermore, all gated FDG PET data sets were reoriented in a second run with deliberately misaligned axes to test the quantification procedure for robustness. Correlation between the results of gated FDG PET and cMRI was very high for EDV and ESV ( R=0.96 and R=0.97) and for LVEF ( R=0.95). With gated FDG PET, there was a non-significant tendency to underestimate EDV (174+/-61 ml vs 179+/-59 ml, P=0.21) and to overestimate ESV (124+/-58 ml vs 122+/-60 ml, P=0.65), resulting in underestimated LVEF values (31.5%+/-9.4% vs 34.2%+/-12.4%, P0.003). The results of reorientations 1 and 2 showed very high correlations (for all R/=0.99). Segmental wall motion analysis revealed good agreement between gated FDG PET data and cMRI (kappa =0.62+/-0.03). In conclusion, despite small systematic differences which contributed mainly to the lower temporal resolution of gated FDG PET, agreement between gated FDG PET and cMRI was good across a wide range of volumes and LVEF values as well as for wall motion analysis. Therefore, gated FDG PET provides clinically relevant information on function and volumes, using the commercially available software package QGS.