Septal and anterior reverse mismatch of myocardial perfusion and metabolism in patients with coronary artery disease and left bundle branch block.

The effects of left bundle branch block (LBBB) on left ventricular myocardial metabolism have not been well investigated. This study evaluated these effects in patients with coronary artery disease (CAD).Sixty-five CAD patients with complete LBBB (mean age, 61.8 ±â€Š9.7 years) and 65 without LBBB (mean age, 59.9 ±â€Š8.4 years) underwent single photon emission computed tomography, positron emission tomography, and contrast coronary angiography. The relationship between myocardial perfusion and metabolism and reverse mismatch score, and that between QRS length and reverse mismatch score and wall motion score were evaluated.The incidence of left ventricular septum and anterior wall reverse mismatching between the two groups was significantly different (P < 0.001 and P = 0.002, respectively). The incidences of normal myocardial perfusion and metabolism in the left ventricular lateral and inferior walls were also significantly different between the two groups (P < 0.001 and P < 0.001, respectively). The incidence of septal reverse mismatching in patients with mild to moderate perfusion was significantly higher among those with LBBB than among those without LBBB (P < 0.001). In CAD patients with LBBB, septal reverse mismatching was significantly more common among those with mild to moderate perfusion than among those with severe perfusion defects (P = 0.002). The correlation between the septal reverse mismatch score and QRS length was significant (P = 0.026).In patients with CAD and LBBB, septal and anterior reverse mismatching of myocardial perfusion and metabolism was frequently present; the septal reverse mismatch score negatively correlated with the QRS interval.

Gated F-18 FDG PET for assessment of left ventricular volumes and ejection fraction using QGS and 4D-MSPECT in patients with heart failure: a comparison with cardiac MRI.

PURPOSE: Ventricular function is a powerful predictor of survival in patients with heart failure (HF). However, studies characterizing gated F-18 FDG PET for the assessment of the cardiac function are rare. The aim of this study was to prospectively compare gated F-18 FDG PET and cardiac MRI for the assessment of ventricular volume and ejection fraction (EF) in patients with HF. METHODS: Eighty-nine patients with diagnosed HF who underwent both gated F-18 FDG PET/CT and cardiac MRI within 3 days were included in the analysis. Left ventricular (LV) end-diastolic volume (EDV), end-systolic volume (ESV), and EF were obtained from gated F-18 FDG PET/CT using the Quantitative Gated SPECT (QGS) and 4D-MSPECT software. RESULTS: LV EDV and LV ESV measured by QGS were significantly lower than those measured by cardiac MRI (both P<0.0001). In contrast, the corresponding values for LV EDV for 4D-MSPECT were comparable, and LV ESV was underestimated with borderline significance compared with cardiac MRI (P = 0.047). LV EF measured by QGS and cardiac MRI showed no significant differences, whereas the corresponding values for 4D-MSPECT were lower than for cardiac MRI (P<0.0001). The correlations of LV EDV, LV ESV, and LV EF between gated F-18 FDG PET/CT and cardiac MRI were excellent for both QGS (r = 0.92, 0.92, and 0.76, respectively) and 4D-MSPECT (r = 0.93, 0.94, and 0.75, respectively). However, Bland-Altman analysis revealed a significant systemic error, where LV EDV (-27.9±37.0 mL) and ESV (-18.6±33.8 mL) were underestimated by QGS. CONCLUSION: Despite the observation that gated F-18 FDG PET/CT were well correlated with cardiac MRI for assessing LV function, variation was observed between the two imaging modalities, and so these imaging techniques should not be used interchangeably.

Shortened acquisition time or reduced-activity dose for gated myocardial perfusion SPECT with new reconstruction algorithm.

To confirm that shortened acquisition time or reduced-activity dose in single-photon emission computed tomography (SPECT) myocardial perfusion imaging reconstructed with Astonish software (AS) does not compromise image quality or diagnostic accuracy. One hundred patients referred for SPECT myocardial perfusion imaging were prospectively studied. The patients were randomly selected to receive the full-dose protocol (group A, n = 54) or the half-dose protocol (group B, n = 46). The patients of group A underwent a 2-day stress/rest protocol. After half-time acquisition, they underwent a full-time acquisition for stress and rest SPECT. Group B underwent a 1-day stress/rest protocol. During peak stress, all patients received an intravenous injection of (99m)Tc-methoxyisobutylisonitrile (MIBI; 5.2 ± 0.6 mCi). After the full-time stress acquisition, the patients underwent a double-time stress acquisition. If the stress image showed a defect, a patient received (99m)Tc-MIBI (19.5 ± 1.7 mCi) at rest on the same day. The rest SPECT acquisition protocol was the same in both groups. The low count (LC) and high count (HC) were acquired for each patient. AS and filtered back projection (FBP) reconstructed each set of raw data. Image quality of perfusion was assessed on a four-point scale. Perfusion parameters and function parameters were calculated by quantitative perfusion SPECT and quantitative gated SPECT. Mean image quality for LC-AS and HC-AS (3.5 ± 0.5 and 3.7 ± 0.5, respectively) was superior to HC-FBP (3.1 ± 0.4) in group A (for all, p < 0.001). LC-AS and HC-AS (3.5 ± 0.5 and 3.6 ± 0.5, respectively) in group B were superior to HC-FBP (3.1 ± 0.3) (for all, p < 0.001). LC-AS, HC-AS and LC-FBP showed high diagnostic concordance with HC-FBP (kappa value was 0.92, 0.92, and 0.94, respectively; all p < 0.001). Cardiac SPECT studies can be acquired with half of the scan time or reduced radioactivity dose and reconstructed by using the AS algorithm without compromising image quality.

Evaluation of left and right ventricular ejection fraction and volumes from gated blood-pool SPECT in patients with dilated cardiomyopathy: comparison with cardiac MRI.

UNLABELLED: This prospective study evaluated the accuracy of electrocardiogram-gated blood-pool SPECT (GBPS) for the assessment of left ventricular (LV) and right ventricular (RV) ejection fraction (EF), end-diastolic volume (EDV), and end-systolic volume (ESV) in patients with dilated cardiomyopathy (DCM), using cardiac magnetic resonance (CMR) imaging as the reference standard. METHODS: Thirty-two patients (24 men and 8 women; mean age, 51 y) with a diagnosis of idiopathic DCM underwent GBPS and CMR. LV and RV parameters including EDV, ESV, and EF from GBPS were calculated using fully automated gradient software and compared with those obtained by CMR. RESULTS: Biventricular volumes were underestimated by GBPS, compared with CMR (P < 0.001). We found no statistical difference between these 2 methods in the assessment of LV EF (P = 0.23), whereas RV EF was overestimated by GBPS (P < 0.001 vs. CMR). Regression analysis yielded significant correlations between GBPS and CMR in the assessments of biventricular parameters (r = 0.83 for LV EDV, 0.88 for LV ESV, 0.89 for LV EF, 0.86 for RV EDV, 0.86 for RV ESV, and 0.62 for RV EF; all P < 0.001). Comparison of the deviations of RV indices between GBPS and CMR with the ratio of RV EDV to LV EDV showed that there was a statistically significant trend for RV volumes to be underestimated and for RV EF to be overestimated as the biventricular volumetric ratio decreased (r = 0.61 for RV EDV, 0.68 for RV ESV, and -0.55 for 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.

[Myocardial perfusion evaluation post percutaneous transluminal septal myocardial ablation in patients with hypertrophic obstructive cardiomyopathy by 99Tc(m) MIBI SPECT MPI].

OBJECTIVE: To evaluate the myocardial perfusion and function in patients with hypertrophic obstructive cardiomyopathy (HOCM) before and after percutaneous transluminal septal myocardial ablation (PTSMA). METHODS: Sixty-eight patients with hypertrophic obstructive cardiomyopathy were included and (99)Tc(m)-MIBI SPECT MPI was applied before and at 1 week after PTSMA, six-month follow-up was finished in 11 patients. Semi quantity and QGS quantity perfusion and function assessment was performed in 17 LV segments. RESULTS: Myocardial perfusion post-PTSMA was significantly reduced in 98% patients, especially in basal anterosepta, basal interseptal, mid-anteroseptal, mid-interseptal and apical septal segments compared with pre-PTSMA (all P < 0.05). Perfusion was significantly increased at 6 months follow-up than at 1 week post-PTSMA but still lower than pre-PTSMA (all P < 0.05). LVEF (evaluated by gated SPECT) was similar before and after the procedure (P > 0.05). Regional wall motion after PTSMA was lower than pre-PTSMA in basal anterior, basal anteroseptal, basal interseptal and basal inferior (P < 0.05). Regional wall thinkening was lower than pre-PTSMA in basal interseptal, mid-anteroseptal, mid-interseptal (P < 0.05). CONCLUSIONS: (99)Tc(m) MIBI SPECT can be used to monitor myocardial perfusion post PTSMA in patients with HOCM.

[Feasibility of in vivo isotope labeled autologous mononuclear bone marrow cells monitoring post cardiac transplantation in a swine model of myocardial infarction].

OBJECTIVE: To observe in vivo stem cell distribution and viability after transplantation by noninvasive imaging of 18F-fluorodeoxyglucose (18F-FDG) labeled autologous mononuclear bone marrow cells. METHODS: Myocardial infarction was established in 8 swine by ligating left anterior descending coronary artery after anesthesia. Bone marrow (20 ml) was drawn through ileum. After isolation, mononuclear bone marrow cells were labeled by radionuclide 18F-FDG and intramyocardially injected into infarction region. Whole body planar scan and myocardial tomography scan were performed immediately, 1 h, 2 h, and 3 h post stem cell injection. Viability and stability of radionuclide labeled stem cells were determined at 3 h post labeling in vitro. RESULTS: The labeling efficiency was (67 +/- 14)%. Mean dose of radioactive in marrow cells was (32 +/- 7) MBq. Trypan blue staining showed in vitro viability was (95 +/- 3)% at 3 h post labeling. After intramyocardial injection, labeled mononuclear bone marrow cell retention rate in infarction region was (83 +/- 6)%, (49 +/- 8)%, (32 +/- 6)% and (24 +/- 5)% immediately, 1 h, 2 h, and 3 h post injection, respectively. CONCLUSIONS: Distribution and viability of stem cell after cardiac transplantation could be effective monitored by 18F-FDG labeled autologous mononuclear bone marrow cell technique in acute stage in this model.