Comparison of exercise and pharmacological stress gated SPECT in detecting transient left ventricular dysfunction.

OBJECTIVE: Transient left ventricular contractile dysfunction (TLVD) is observed owing to post-exercise stunning in patients with coronary artery disease (CAD). Pharmacological stimulation differs from exercise stress because it does not cause demand ischemia. The aim of this study was to determine whether TLVD could also be seen after pharmacological stress (dipyridamole). METHODS: Of the patients in whom gated single-photon emission computed tomography (GSPECT) was performed in our institution from January 2004 to April 2007, 439 subjects with known or suspected CAD were included in the study. GSPECT was performed for all patients following exercise (group I, n = 220) or pharmacological stress (group II, n = 219) according to a 2-day (stress-rest) protocol after injection of Tc-99m methoxyisobutyl-isonitrile (MIBI). Stress, rest, and difference (stress-rest value) left ventricular ejection fractions (SLVEF, RLVEF, and DLVEF) and transient ischemic dilatation (TID) ratio were derived automatically. Summed stress score, summed rest score, and summed difference score (SDS) for myocardial perfusion were calculated using a 20-segment model and a five-point scoring system. An SDS > 3 was considered as ischemic. On the basis of the perfusion findings, patients were subdivided into a normal (group A, n = 216) and ischemia group (group B, n = 223). DLVEF and perfusion scores of all groups were compared. Relationships between DLVEF and perfusion, and between TID ratio and DLVEF were also evaluated. RESULTS: Stress-induced ischemia was observed in 223 of 439 patients (50.8%). In group A, the difference between stress and rest LVEF values was not significant (P = 0.670 and P = 0.200 for groups IA and IIA, respectively). However, LVEF was significantly decreased after stress compared with rest values for group B (P < 0.0001 for groups IB and IIB). TLVD (< or =-5% for DLVEF) was observed in 20 of 216 (9%) and 81 of 223 subjects (36%) in patients in groups A and B, respectively (P < 0.0001). In group I, we found TLVD in 46 of 119 (39%) and 12 of 101 (12%) subjects, in patients with and without ischemia, respectively (P < 0.0001). On the other hand, in group II, TLVD was detected in 35 of 104 (34%) and 8 of 115 (7%) patients with and without ischemia, respectively (P < 0.0001). And also, we found significant good correlations between TID ratios and DLVEF values in four subgroups (r = -0.55, r = -0.62, r = -0.59, and r = -0.41; for groups IA, IB, IIA, and IIB, respectively, P < 0.0001 for all). CONCLUSIONS: Dipyridamole is believed to be less likely than exercise to induce ischemia. However, in this study, TLVD after stress was observed following not only exercise but also pharmacological stress, consistent with ischemia.

Comparison of gated SPECT, echocardiography and cardiac magnetic resonance imaging for the assessment of left ventricular ejection fraction and volumes.

BACKGROUND: Left ventricular ejection fraction (LVEF), end-diastolic volume (EDV) and end-systolic volume (ESV) can be determined non-invasively by two-dimensional enchocardiography (ECHO), gated sinle photon emission computed tomography (GSPECT) and cardiac magnetic resonance imaging (CMRI). This study was designed to analyze the concordance between LVEF, EDV and ESV values derived from ECHO, GSPECT and CMRI. METHODS: ECHO, GSPECT and CMRI were performed in a group of 21 patients with suspected coronary artery disease. LVEF, EDV and ESV values were calculated. RESULTS: The mean LVEF measured with GSPECT, ECHO and CMRI were 55.9+/-17.8%, 55.7+/-16.4% and 56.4+/-15.7%, respectively. The mean EDV measured with GSPECT, ECHO and CMRI were 109.2+/-42.45 mL, 127.5+/-42.2 mL, 91.1+/-38.0 mL, respectively. The mean ESV measured with GSPECT, ECHO and CMRI were 54.2+/-41.2 mL, 59.9+/-37.6 mL and 41.8+/-26.9 mL, respectively. The results of linear regression analysis showed very good correlation between LVEF and ESV values derived from GSPECT, ECHO adn CMRI (r=0.91, r=0.92, r=0.97 for LVEF and r=0.86, r=0-91, r=0.91 for ESV, P<0.01). Good correlations were found between EDV values obtained from GSPECT, ECHO and CMRI (r=0.71, r=0.68, r=0.73, P<0.01). Agreement between these techniques in LVEF values was also good, but not in LV volumes, according to Bland-Altman plots. CONCLUSIONS: This study showed good overall correlations between LVEF, EDV and ESV values derived from GSPECT, ECHO and CMRI. LVEF obtained from any of these three imaging modalities could be used interchangeably. However, care should be taken in comparing LV volumes.

The assessment of septal wall motion in patients undergoing CABG by myocardial perfusion-gated SPECT.

PURPOSE: In this study, we aimed to assess the presence and prevalence of paradoxical septal motion (PSM) by myocardial perfusion-gated single-photon emission computed tomography (SPECT) imaging in patients undergoing coronary artery bypass grafting (CABG). METHODS: A total of 172 patients (145 men and 27 women, with a mean age of 64.81 ± 8.93 years) undergoing CABG surgery were included in the study. All selected scintigraphic studies of the patients undergoing CABG were reprocessed. Semiquantitative interpretation of septal perfusion, wall motion, and wall thickening was performed with QPS and QGS programs. Phase analysis parameters were also obtained using the Emory Cardiac Toolbox. According to myocardial perfusion-gated SPECT results, the patients were trichotomized as follows: group 1 (nonischemic PSM): regular perfusion and thickening of the septal wall and abnormal motion of the septal wall; group 2 (ischemic PSM): abnormal perfusion, motion, and thickening of the septal wall; group 3 (non-PSM): normal perfusion, motion, and thickening of the septal wall. The data in each of the three groups were compared using Student's t-test and one-way analysis of variance. RESULTS: No PSM (normal perfusion, motion, and thickening of the septal wall) was observed in 19.2% of patients undergoing CABG, whereas nonischemic PSM (regular perfusion and thickening of the septal wall and abnormal motion of the septal wall) was observed in 60.5% of patients and ischemic PSM (abnormal perfusion, motion and thickening of the septal wall) was seen in 20.3% of patients. CONCLUSION: According to our study results, PSM is fairly common in patients undergoing CABG. It will be beneficial to use myocardial perfusion scintigraphy-gated SPECT, which is a noninvasive examination method, to identify the presence of PSM and investigate whether it is accompanied by ischemia or infarction.