| Objective:This prospective study was aimed to evaluate the accuracy of electrocardiogram-gated blood-pool single photon emission computed tomography (GBPS) for the assessment of left (LV) and right ventricular (RV) ejection fractions (EF), end-diastolic (EDV) and end-systolic volumes (ESV) in patients with dilated cardiomyopathy (DCM), compared with cardiac magnetic resonance (CMR) imaging as the reference standard.Methods:Thirty-two patients (24men and8women, mean age of51±14years old) with a diagnosis of idiopathic DCM underwent GBPS and CMR. LV and RV parameters including EDV, ESV and EF from GBPS were calculated using QBS (ver.2007) software and compared with those obtained by CMR.Results:Biventricular volumes were underestimated by GBPS compared with CMR (LV EDV,229±68ml versus261±69ml; LV ESV,188±68ml versus216±70ml; RVEDV,170±36ml versus195±37ml; and RV ESV,117±37ml versus144±37ml; all p<0.001).No statistical difference was found in the assessment of LV EF(19%±7%versus19%±7%;p=0.23) between these2methods, whereas RV EF was overestimated by GBPS (32%±9%versus26%±6%;p<0.001). Linear regression analysis yielded significant correlations between GBPS and CMR in the assessments of biventricular parameters (r=0.83for LV EDV, r=0.88for LV ESV, r=0.89for LV EF, r=0.86for RV EDV, r=0.86for RV ESV, and r=0.62for RV EF, all p<0.001). Comparing the deviations of RV indices between GBPS and CMR with the ratio of RV EDV to LV EDV (RV EDV/LV EDV) showed that there was statistically significant trend that RV volumes to be underestimated and RV EF to be overestimated as the biventricular volumetric ratio decreased (r=0.61for RV EDV; r=0.68for RV ESV; and r=-0.55for RV EF; all p<0.001). Conclusion:For patients with DCM, GBPS correlated well with CMR for the assessment of biventricular parameters, but RV indices should be cautiously interpreted. Objective:Coronary artery bypass grafting (CABG) is one of the most recommended therapeutic regime in treating coronary artery disease. Taking this operation, targeted coronary will be revascularized, leading to improved blood perfusion of the viable myocardium. The purpose of this study is two folds. First, to explore the utility of a new semi-quantitative scoring system-myocardial "viability index", which integrating the degree and extent of viable myocardium, in assessing the preoperative left ventricular function and in evaluating the postoperative functional recovery in patients underwent CABG with the use of99mTc-MIBI/18F-FDG SPECT. Second, to investigate whether the specific myocardial "viability index" in the LAD, LCX, and RCA territory, and in the apical-, anterior-, septal-, lateral-, and inferior-region is predictive of the postsurgical recovery.Methods:A retrospective study was performed in patients with coronary artery disease who underwent99mTc-MIBI/18F-FDG SPECT before receiving CABG in Fu Wai Hospital between January1,2000and December31,2005. All patients included had a documented history of myocardial infarction. Patients were excluded if they had any of the following conditions:cardiac tumor, ventricular aneurysm resection, significant valvular heart disease, unsuccessful CABG, or died during hospitalization. Based on the standard17-segment model, both perfusion and18F-FDG imaging were visually evaluated by2nuclear physicians blinded to the clinical data. Each segmental score reached consensus between the2readers. All segments were scored on a4-point scale as:0=both normal perfusion and metabolism;1=perfusion-metabolism mismatch;2=perfusion-metabolism partial-mismatch; and3=perfusion-metabolism match. Global ventricular "viability index" was obtained by dividing the sum of all segmental scores with17. LAD-, LCX-, and RCA-specific "viability index" was calculated respectively by dividing the summed scores of each territory with the corresponding segments perfused by each coronary artery. Region-based (apical-, anterior-, septal-, lateral-, and inferior-region)"viability index" was gained by dividing the sum of each regional scores with the corresponding segments. Thus, the more the "viability index" deviates from0, the worse the myocardial viability is. Linear regression analyses were performed to determine the relationship between each of the above "viability index" and the preoperative LVEF and LVEDD, and with the postoperative durations of ICU hospitalization and mechanical ventilation. The correlations of "viability index" and the incidence of postsurgical low cardiac output syndrome and complications were also analyzed.Results:Sixty-seven patients were finally recruited (60men and7women, mean age63±10years). The mean global "viability index" was0.68±0.43.The LAD-, LCX-, and RCA-specific "viability index" was0.83±0.74,0.30±0.68and0.85±0.89, respectively. The apical-, anterior-, septal-, inferior-, and lateral-"viability index" was1.84±1.23,0.67±0.84,0.61±0.91,1.05±1.10and0.30±0.68, respectively. Linear correlations were demonstrated between global "viability index" and preoperative LVEF (r=-0.67,p <0.001) and LVEDD (r=0.66, p<0.001), and postoperative durations of ICU hospitalization (r=0.56, p<0.001) and of mechanical ventilation (r=0.51, p<0.001). Patients who experienced postsurgical low cardiac output syndrome and who encountered postoperative complication showed higher global "viability index" than those without (0.91±0.42versus0.56±0.38, p=0.002; and0.86±0.43versus0.57±0.39, p=0.006). Besides, the LAD-, RCA-, anterior-, and inferior-specific "viability index" were also correlated to the preoperative LVEF and LVEDD (allp<0.05), and the LAD-, LCX-, RCA-, anterior-and lateral-specific "viability index" were related to the durations of postoperative ICU hospitalization and of mechanical ventilation (all p<0.05). Higher LCX-, that is higher lateral-"viability index" was observed in patients who had low cardiac output syndrome and who encountered postoperative complication than those without (both p<0.05).Conclusion:In patients with coronary artery disease who underwent CABG, myocardial viability evaluated by myocardial "viability index" and99mTc-MIBI/18F-FDG SPECT is feasible in estimating myocardial viability status. The global "viability index" was closely related to the preoperative cardiac function and postsurgical recovery. Besides, territory-and region-based "viability index" were also predictive of postoperative recovery. |
PDF Full Text Request