[Show abstract][Hide abstract] ABSTRACT: Our goal was to validate the feasibility of 99mTc-duramycin as a potential apoptosis probe for monitoring tumor response to paclitaxel in breast cancer xenografts. The binding of 99mTc-duramycin to phosphatidylethanolamine was validated in vitro using paclitaxel-treated human breast carcinoma MDA-MB-231 cells. Female BALB/c mice (n = 5) bearing breast cancer xenografts were randomized into 2 groups and intraperitoneally injected with 40 mg/kg paclitaxel or phosphate-buffered saline. 99mTc-duramycin (37-55.5 MBq) was injected at 72 hours posttreatment, and single-photon emission computed tomography/computed tomography was performed at 2 hours postinjection. Apoptotic cells and activated caspase 3 in explanted tumor tissue were measured by flow cytometry. Cellular ultrastructural changes were assessed by light and transmission electron microscopy. 99mTc-duramycin with radiochemical purity of >90% exhibited rapid blood clearance and predominantly renal clearance. The tumor-to-muscle ratio in the paclitaxel-treated group (5.29 ± 0.62) was significantly higher than that in the control. Tumor volume was decreased dramatically, whereas tumor uptake of 99mTc-duramycin (ex vivo) significantly increased following paclitaxel treatment, which was consistent with apoptotic index, histological findings, and ultrastructural changes. Our data demonstrated the feasibility of 99mTc-duramycin for early detection of apoptosis after paclitaxel chemotherapy in breast carcinoma xenografts.
[Show abstract][Hide abstract] ABSTRACT: Aims:
Right ventricular (RV) glucose metabolism disorder in pulmonary arterial hypertension (PAH) has been studied using (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) imaging with inconsistent results. We aimed to quantitatively assess RV glucose metabolism and further identify its role of monitoring RV function in idiopathic PAH (IPAH) patients in a longitudinal study.
Methods and results:
Twenty-seven treatment-naïve IPAH patients and 21 healthy control subjects performed FDG-PET dynamic scan for quantification of the rate of myocardium glucose utilization (rMGU) and echocardiography for assessment of cardiac function. Right heart catheterization was conducted for IPAH patients for haemodynamic measurement. A subgroup of 14 patients repeated FDG-PET and echocardiography after 6-month treatment. RV rMGU was significantly increased compared with controls; while the rMGU in left ventricle showed no difference. RV rMGU was significantly correlated with pulmonary artery pressure, pulmonary vascular resistance, RV Tei index, and right atrial area, and negatively correlated with RV ejection fraction (RVEF) and tricuspid annular plane systolic excursion. Six of 14 patients with increased RV rMGU after 6-month treatment showed no change in RVEF, 6-min walk distance (6MWD), and RV Tei index; however, the other 8 patients with decreased RV rMGU demonstrated significantly increased RVEF and 6MWD and decreased RV Tei index. Notably, the change in RV rMGU of 14 patients was significantly correlated with the change in 6MWD and RV Tei index.
Increased RV rMGU of IPAH correlates with RV dysfunction and RV pressure overload. The change in RV glucose metabolism may help monitor RV function after treatment.
No preview · Article · Nov 2015 · European Heart Journal Cardiovascular Imaging
[Show abstract][Hide abstract] ABSTRACT: Purpose:
Metabolic changes occur in the right ventricle (RV) under increased afterload in pulmonary arterial hypertension. FDG PET imaging has potential to assess RV function. In this study, we aimed to determine the prognostic value of metabolic changes of RV using FDG PET imaging in idiopathic pulmonary arterial hypertension (IPAH).
Patients and methods:
In this prospective investigation, patients newly diagnosed with IPAH were recruited. Patients underwent right heart catheterization, FDG PET imaging, and cardiac MR (CMR) within 1 week. Right ventricle hemodynamics, glucose metabolism derived from the FDG uptake levels, and functional parameters were obtained. The FDG uptake ratio between the RV and the left ventricle (LV) and its relation with the patients' survival were analyzed.
A total of 45 IPAH patients were enrolled in this study, which included 13 male (28.9%) and 32 female (71.1%). The median follow-up time of this study was 1043 days. At the end of the follow-up, 36 patients survived, whereas 9 patients were deceased because of right heart failure. Multivariate Cox proportional hazard analysis showed that the ratio between the corrected RV and LV FDG uptake (cRV/LV) in both glucose-loading (cRV/LVg) and fasting (cRV/LVf) conditions independently predicted the mortality after adjusting for pulmonary vascular resistance index, mean right atrial pressure, and World Health Organization functional class. Kaplan-Meier survival analysis showed that patients with cRV/LVf greater than 143.65% in fasting condition (log rank, P = 0.030) or cRV/LVg greater than 120.55% in glucose-loading condition (log rank, P = 0.014) had worse prognosis.
The FDG uptake ratio between the RV and LV can be an independent predictor for long-term prognosis of IPAH patients.
No preview · Article · Sep 2015 · Clinical nuclear medicine
[Show abstract][Hide abstract] ABSTRACT: In dilated cardiomyopathy (DCM), there are limited data on right ventricular (RV) glucose metabolism assessed by [(18)F]fludeoxyglucose positron emission tomography ((18)F-FDG PET) imaging. We aimed to characterize RV glucose metabolism and investigate the prognostic significance of RV FDG uptake in DCM.
(18)F-FDG PET imaging and cardiac magnetic resonance imaging (MRI) were performed in 63 consecutive DCM patients within an interval of 3-7 days. There was a significant correlation between RVEF and RV FDG uptake whether corrected RV standard uptake value (cRVSUV) (r = -0.571, P < .001) or the relative RV FDG uptake determined as the ratio of RV to left ventricular (LV) corrected SUV (cR/L) (r = -0.405, P < .001) was used. During a median follow-up period of 804 days, 15 patients (23.8%) reached the primary endpoint of all-cause mortality or heart transplantation. On univariate Cox analysis, cRVSUV > 7.01 and cR/L > 0.795 were significantly associated with the overall survival (hazard ratio [HR] 5.415, 95% confidence interval [CI] 1.945-15.078, P < .001; HR 6.422, 95% CI 2.250-18.332, P < .001). Patients with increased RV FDG uptake had a worse outcome (cRVSUV > 7.01 vs cRVSUV ≤ 7.01, log-rank 13.085, P < .001; cR/L > 0.795 vs cR/L ≤ 0.795, log-rank 15.695, P < .001). On multivariate analysis, cR/L > 0.795 remained a significant independent predictor of the endpoint (HR 5.001, 95% CI 1.641-15.239, P = .004), while cRVSUV > 7.01 showed no significance (HR 2.611; 95% CI 0.797-8.558; P = .113).
Increased RV FDG uptake was associated with RV dysfunction and may be a prognostic predictor of all-cause mortality or heart transplantation in patients with DCM.
No preview · Article · Aug 2015 · Journal of Nuclear Cardiology
[Show abstract][Hide abstract] ABSTRACT: Transthoracic Doppler-echocardiography (TTE) can estimate mean pulmonary arterial pressure (MPAP) and pulmonary capillary wedge pressure (PCWP) reliably, and cardiac magnetic resonance (CMR) is the best modality for non-invasive measurement of cardiac output (CO). We speculated that the combined use of TTE and CMR could provide a feasible method for non-invasive measurement of pulmonary vascular resistance (PVR) in pulmonary arterial hypertension (PAH).
[Show abstract][Hide abstract] ABSTRACT: 99mTc-3P-RGD2 and SPECT/CT were valuable tools for selecting patient likely benefit from integrin α v β 3 blocking therapy. To evaluate the feasibility of 99mTc-3P-RGD2 imaging to detect head and neck squamous cell carcinoma, 99mTc-3P-RGD2 was prepared and the relationship between its accumulation and integrin α v β 3 expression in nude mice bearing HEP-2 or CNE-1 carcinoma xenograft were analyzed. This study demonstrated that 99mTc-3P-RGD2, with high affinity to integrin α v β 3, will provide basis for α v β 3 involved individual therapy.
Preview · Article · Jun 2015 · Journal of Radioanalytical and Nuclear Chemistry
[Show abstract][Hide abstract] ABSTRACT: 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 ± 9.7 years) and 65 without LBBB (mean age, 59.9 ± 8.4 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.
[Show abstract][Hide abstract] ABSTRACT: When pathologically externalized, phosphatidylethanolamine (PE) is a potential surrogate marker for detecting tissue injuries. 99mTc-labeled duramycin is a peptide-based imaging agent that binds PE with high affinity and specificity. The goal of the current study was to investigate the clearance kinetics of 99mTc-labeled duramycin in a large animal model (normal pigs) and to assess its uptake in the heart using a pig model of myocardial ischemia-reperfusion injury.
The clearance and distribution of intravenously injected 99mTc-duramycin were characterized in sham-operated animals (n = 5). In a closed chest model of myocardial ischemia, coronary occlusion was induced by balloon angioplasty (n = 9). 99mTc-duramycin (10–15 mCi) was injected intravenously at 1 hour after reperfusion. SPECT/CT was acquired at 1 and 3 hours after injection. Cardiac tissues were analyzed for changes associated with acute cellular injuries. Autoradiography and gamma counting was used to determine radioactivity uptake. For the remaining animals, 99mTc-tetrafosamin scan was performed on the second day to identify the infarct site.
Intravenously injected 99mTc-duramycin cleared from circulation predominantly via the renal/urinary tract with an α-phase half-life of 3.6 ± 0.3 minutes and β-phase half-life of 179.9 ± 64.7 minutes. In control animals, the ratios between normal heart and lung were 1.76 ± 0.21, 1.66 ± 0.22, 1.50 ± 0.20 and 1.75 ± 0.31 at 0.5, 1, 2 and 3 hours post injection, respectively. The ratios between normal heart and liver were 0.88 ± 0.13, 0.80 ± 0.13, 0.82 ± 0.19 and 0.88 ± 0.14. In vivo visualization of focal radioactivity uptake in the ischemic heart was attainable as early as 30 min post injection. The in vivo ischemic-to-normal uptake ratios were 3.57 ± 0.74 and 3.69 ± 0.91 at 1 and 3 hours post injection, respectively. Ischemic-to-lung ratios were 4.89 ± 0.85 and 4.93 ± 0.57; and ischemic-to-liver ratios were 2.05 ± 0.30 to 3.23 ± 0.78. The size of 99mTc-duramycin positive myocardium was qualitatively larger than the infarct size delineated by the perfusion defect in 99mTc-tetrafosmin uptake. This was consistent with findings from tissue analysis and autoradiography.
99mTc-duramycin was demonstrated, in a large animal model, to have suitable clearance and biodistribution profiles for imaging. The agent has an avid target uptake and a fast background clearance. It is appropriate for imaging myocardial injury induced by ischemia/reperfusion.
Full-text · Article · Sep 2014 · Nuclear Medicine and Biology
[Show abstract][Hide abstract] ABSTRACT: It is known that patients with pulmonary hypertension (PH) can have elevated F-FDG uptake in the right ventricle (RV) on PET imaging. This study was designed to assess possible relationship between FDG uptake of ventricles and the function/hemodynamics of the RV in patients with PH.
Thirty-eight patients with PH underwent FDG PET imaging in both fasting and glucose-loading conditions. The standard uptake value (SUVs) corrected for partial volume effect in both RV and left ventricle (LV) were measured. The ratio of FDG uptake between RV to LV (SUVR/L) was calculated. Right heart catheterization and cardiac magnetic resonance (CMR) were performed in all patients within 1 week. The FDG uptake levels by the ventricles were compared with the result form the right heart catheterization and CMR.
The SUV of RV (SUVR) and SUV of LV were significantly higher in glucose-loading condition than in fasting condition. In both fasting and glucose-loading conditions, SUVR and SUVR/L showed reverse correlation with right ventricular ejection fraction derived from CMR. In addition, in both fasting and glucose-loading conditions, SUVR and SUVR/L showed positive correlations with pulmonary vascular resistance. However, only SUVR/L in glucose-loading condition could independently predict right ventricular ejection fraction after adjusted for age, body mass index, sex, mean right atrial pressure, mean pulmonary arterial pressure, and pulmonary vascular resistance (P = 0.048).
The FDG uptake of RV increases with decreased right ventricular function in patients with PH. Increased FDG uptake ratio between RV and LV might be useful to assess the right ventricular function.
No preview · Article · Mar 2014 · Clinical nuclear medicine
[Show abstract][Hide abstract] ABSTRACT: 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.
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.
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.
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.
[Show abstract][Hide abstract] ABSTRACT: 18F-annexin V was labeled with 18F-SFB, after size-column exclusion chromatography, the radiochemical purity exceeded 95 %. High focal uptake of 18F-annexin V was visualized in myocardium ischemia–reperfusion injury (RI) area of rat models, which was consistent with autoradiography, the standard uptake values (SUV) of RI was 7.93 ± 3.85, whereas remote viable myocardium was 1.02 ± 0.19 (p < 0.001). Histological staining and flow cytometry confirmed ongoing apoptosis in RI. Activated caspase-3, cells in sub-G0 phase, apoptotic cells measuring with FITC-annexin V in RI was 23.04 ± 2.25, 4.62 ± 1.96, 8.84 ± 1.25 respectively, whereas activated caspase-3 in remote viable myocardium was only 3.49 ± 1.83 (p < 0.001). Therefore, 18F-annexin V can be serve as a candidate for the early detection of myocardial ischemia and injury.
No preview · Article · Dec 2013 · Journal of Radioanalytical and Nuclear Chemistry
[Show abstract][Hide abstract] ABSTRACT: The relationship between luminal stenosis measured by coronary CT angiography and stress-induced ischemia by SPECT myocardial perfusion imaging is not clearly defined. The aims of this study were to evaluate the relationship between stenosis severity by coronary CT angiography and abnormal SPECT finding and to explore the impact of clinical factors on this relationship.
Seven hundred six consecutive patients with suspected coronary artery disease between January 2008 and October 2010 were prospectively enrolled.
SPECT revealed 348 reversible and 58 fixed defects in 91 patients. Coronary CT angiography revealed that 339 patients had a maximal luminal stenosis 50% or greater. Total coronary artery calcium score was calculated in 428 patients, including 193 without calcification as well as 128 with mild, 59 with moderate, and 48 with severe-to-extensive calcification. Sensitivity, specificity, positive predictive value and negative predictive value (NPV) of coronary CT angiography for detecting abnormal SPECT finding were, respectively, 48.4%, 90.4%, 42.7%, and 92.2% on a patients' level and 40.2%, 95.6%, 33.6%, and 96.6% on vascular level when cutoff value of stenosis was set at 75%. Receiver operating characteristic analysis showed that the best cutoff value of stenosis for detecting abnormal SPECT finding was 55% on patients' level and 43% on vascular level. Patients with severe-to-extensive calcification had lowest specificity (56.3%) and NPV (69.2%). The sensitivity and positive predictive value of coronary CT angiography were not affected by any clinical factors (P = nonsignificant), whereas the specificity was higher in female patients, population younger than 60 years, and population without hypertension or family history of coronary artery disease (P < 0.05), and the NPV was higher among female patients and population without hypertension (P < 0.05).
Coronary CT angiography has good agreement with stress/rest myocardial perfusion SPECT imaging. Coronary calcification and several clinical factors could affect the specificity and NPV of coronary CT angiography for detecting abnormal SPECT finding.
No preview · Article · Aug 2013 · Clinical nuclear medicine
[Show abstract][Hide abstract] ABSTRACT: In tumors the process of apoptosis occurs over an interval of time after chemotherapy. It is important to determine the best time for detecting apoptosis by in vivo imaging. In this study, we evaluated the dynamics and feasibility of imaging non-small cell lung cancer (NSCLC) apoptosis induced by paclitaxel treatment using a (99)Tc(m)-labeled Annexin V recombinant with ten consecutive histidines (His10-Annexin V) in a mouse model.
(99)Tc(m)-His10-Annexin V was prepared by one step direct labeling; radio-chemical purity (RCP) and radio-stability was tested. The binding of (99)Tc(m)-His10-Annexin V to apoptotic cells was validated in vitro using camptothecin-induced Jurkat cells. In vivo bio-distribution was determined in mice by dissection. The human H460 NSCLC tumor cell line (H460) tumor-bearing mice were treated with intravenous paclitaxel 24, 48 and 72 hours later. (99)Tc(m)-His10-Annexin V was injected intravenously, and planar images were acquired at 2, 4 and 6 hours post-injection on a dual-head gamma camera fitted with a pinhole collimator. Tumor-to-normal tissue ratios (T/NT) were calculated by ROI analysis and they reflected specific binding of (99)Tc(m)-His10-Annexin V. Mice were sacrificed after imaging. Caspase-3, as the apoptosis detector, was determined by flow cytometry, and DNA fragmentation was analyzed by the terminal deoxynucleotidytransferase mediated dUTP nick-end labeling (TUNEL) assay. Nonspecific accumulation of protein was estimated using bovine serum albumin (BSA). The imaging data were correlated with TUNEL-positive nuclei and caspase-3 activity.
(99)Tc(m)-His10-Annexin V had a RCP > 98% and high stability 2 hours after radio-labeling, and it could bind to apoptotic cells with high affinity. Bio-distribution of (99)Tc(m)-His10-Annexin V showed predominant uptake in kidney, relatively low uptake in myocardium, liver and gastrointestinal tract, and rapid clearance from blood and kidney was observed. The T/NT was significantly increased after paclitaxel treatment, whereas it was low in untreated tumors (T/NT = 1.43 ± 0.18). The %ID/g activity in Group 2 (24 hours), Group 3 (48 hours) and Group 4 (72 hours) after treatment was 2.55 ± 0.73, 3.35 ± 1.10, and 3.4 ± 0.96, respectively. Whereas in the non-treated group, Group 1, %ID/g was 1.10 ± 0.18. The radiotracer uptake was positively correlated to the apoptotic index (r = 0.852, P < 0.01), as well as caspase-3 activity (r = 0.816, P < 0.01).
This study addresses the dynamics and feasibility of imaging non-small cell lung tumor apoptosis using (99)Tc(m)- His10-Annexin V.
No preview · Article · Aug 2013 · Chinese medical journal
[Show abstract][Hide abstract] ABSTRACT: Pulmonary arterial hypertension (PAH) is a disease of progressive vascular remodeling, characterized by dysregulated growth of pulmonary vascular cells and inflammation. A prevailing view is that abnormal cellular metabolism, notably aerobic glycolysis which increases glucose demand, underlies the pathogenesis of PAH. Increased lung glucose uptake has been reported in animal models. There are few data from patients with PAH.
Dynamic PET imaging with fluorine-18 labelled 2-fluoro-2-deoxyglucose ((18)FDG) ligand with kinetic analysis demonstrated increased mean lung parenchymal uptake in 20 patients with PAH, 18 idiopathic PAH (IPAH, FDG score: 3.27±1.22) and 2 patients with connective tissue disease (5.07 and 7.11), compared to controls (2.02±0.71, P<0.05). Further compartment analysis confirmed increased lung glucose metabolism in IPAH. Lung (18)FDG uptake and metabolism varied within the IPAH population and within the lungs of individual patients, consistent with the recognized heterogeneity of vascular pathology in this disease. The monocrotaline rat PAH model also showed increased lung (18)FDG uptake, which was reduced along with improvements in vascular pathology after treatment with dicholoroacetate (DCA) and two tyrosine kinase inhibitors, imatinib and sunitinib. Hyper-proliferative pulmonary vascular fibroblasts isolated from IPAH patients exhibited upregulated glycolytic gene expression, along with increased cellular (18)FDG uptake; both were reduced by DCA and imatinib.
Some patients with IPAH exhibit increased lung (18)FDG uptake. (18)FDG PET imaging is a tool to investigate the molecular pathology of PAH and its response to treatment.
[Show abstract][Hide abstract] ABSTRACT: To assess the diagnostic accuracy of ventilation/perfusion (V/Q) single photon emission CT (SPECT) as compared to computed tomographic pulmonary angiography (CTPA) for pulmonary embolism (PE).
In this prospective multicenter study, 111 patients in whom acute or sub-acute PE was clinically confirmed or suspected were enrolled. The patients underwent one-day method V/Q lung scan (including SPECT and planar imaging) within 3 days before and after completion of CTPA. The European Association of Nuclear Medicine (EANM) guidelines for ventilation/perfusion scintigraphy (2009) reference was used as the evaluation criteria of V/Q SPECT imaging. The refined modified prospective investigation of pulmonary embolism diagnosis (RM-PIOPED) criteria was used for evaluation of planar imaging. According to the direct and indirect signs of PE, the imaging of CTPA was evaluated. All patients were followed for at least 6 months. A diagnosis was finally made by consensus of respiratory physicians, radiologists and nuclear medicine physicians based on the clinical data, laboratory tests, imaging features and follow-up results. The difference among diagnostic methods was evaluated for significance using chi-square test. The receiver operator characteristic (ROC) curve was drawn according to the results of the 3 diagnostic tests. The area under ROC curve (AUC) was calculated and compared. P < 0.05 was considered statistically significant.
Among the 111 patients, PE was confirmed in 80, and excluded in 31. The diagnostic sensitivity/specificity/accuracy of V/Q SPECT, planar imaging, and CTPA were 85.9%/93.5%/88.1%, 75.7%/92.9%/81.4%, and 85.5%/90.0%/86.8%, respectively. By ROC curve analysis, the AUC values of V/Q SPECT, planar imaging and CTPA were 0.898, 0.838, and 0.877, respectively; with 95% confidence intervals [CI] 0.831 to 0.966, 0.759 to 0.917, and 0.801 to 0.954, respectively. The area of the fitted smooth ROC curve was statistically significant (P < 0.05) as compared with the area under the reference line.
The results indicate that SPECT V/Q imaging is superior to V/Q planar scan and CTPA in the diagnosis of PE.
No preview · Article · Mar 2013 · Zhonghua jie he he hu xi za zhi = Zhonghua jiehe he huxi zazhi = Chinese journal of tuberculosis and respiratory diseases
[Show abstract][Hide abstract] ABSTRACT: Purpose:
To investigate the value of gated F-18 FDG PET/CT on left ventricular (LV) dyssynchrony assessment in comparison with gated Tc-99m sestamibi SPECT in patients with coronary artery disease (CAD).
The data of 100 consecutive CAD patients who underwent both gated myocardial Tc-99m sestamibi SPECT and F-18 FDG PET/CT imaging were analyzed. Phase standard deviation (SD) and histogram bandwidth (BW) were derived from phase analysis using Cedars software package. The correlation and agreement of SD and BW between Tc-99m sestamibi SPECT and F-18 FDG PET/CT were examined. Myocardial viability and the site of latest activation assessed by the two imaging methods were compared as well.
A moderate correlation for SD (r = 0.58, p < 0.0001) and BW (r = 0.60, p < 0.0001) was found between gated SPECT and gated F-18 FDG PET/CT. Bland-Altman analysis revealed an overestimation of SD and BW (6.4° ± 14.3° and 22.0° ± 46.8°) by gated F-18 FDG PET/CT. Multivariate logistic regression analysis identified that significant LV remodeling on SPECT imaging, LV functional parameters and F-18 FDG uptake ratio of myocardium to blood pool (SUVM/B) were associated with the overestimation. Myocardial SPECT and F-18 FDG PET/CT had a 67.1 % identity in determining the latest activation site and 5.2 % more viable myocardium was detected by F-18 FDG PET/CT than SPECT.
Gated F-18 FDG PET/CT moderately correlated with gated Tc-99m sestamibi SPECT in assessing LV dyssynchrony. Gated F-18 FDG PET/CT phase analysis should be cautiously applied in CAD patients with significant LV remodeling on SPECT imaging, severe LV functional impairment or poor myocardial F-18 FDG uptake.
Full-text · Article · Jan 2013 · Annals of Nuclear Medicine
[Show abstract][Hide abstract] ABSTRACT: Background:
Right ventricular (RV) function is a powerful predictor of survival in patients with pulmonary hypertension (PH), but noninvasively assessing RV function remains a challenge. The aim of this study was to prospectively compare gated (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) myocardial imaging (gated PET), cardiac magnetic resonance (CMR), and cardiac computed tomography (CCT) for the assessment of RV volume and ejection fraction in patients with PH.
Twenty-three consecutive patients aged more than 16 years diagnosed with PH were included. All patients underwent gated PET, CMR, and CCT within 7 days. Right ventricular end-diastolic volume (RVEDV), right ventricular end-systolic volume (RVESV), and right ventricular ejection fraction (RVEF) were calculated by three imaging modalities. RV (18)F-FDG uptake was determined as RV-corrected standardized uptake value (SUV), and the ratio of RV to left ventricular (LV)-corrected SUV (Corrected SUV R/L).
Gated PET showed a moderate correlation (r = 0.680, P < .001) for RVEDV, good correlation for RVESV (r = 0.757, P < .001) and RVEF (r = 0.788, P < .001) with CMR, and good correlation for RVEDV (r = 0.767, P < .001), RVESV (r = 0.837, P < .001), and RVEF (r = 0.730, P < .001) with CCT. Bland-Altman analysis revealed systematic underestimation of RVEDV and RVESV and overestimation of RVEF with gated PET compared with CMR and CCT. The correlation between RVESV (r = 0.863, P < .001), RVESV (r = 0.903, P < .001), and RVEF (r = 0.853, P < .001) of CMR and those of CCT was excellent; Bland-Altman analysis showed only a slight systematic variation between CMR and CCT. There were statistically significant negative correlations between RV-corrected SUV and RVEF-CMR (r = -0.543, P < .01), Corrected SUV R/L and RVEF-CMR (r = -0.521, P < .05), RV-corrected SUV and RVEF-CCT (r = -0.429, P < .05), Corrected SUV R/L and RVEF-CCT (r = -0.580, P < .01), respectively.
Gated PET had moderate-to-high correlation with CMR and CCT in the assessments of RV volume and ejection fraction. It is an available method for simultaneous assessing of RV function and myocardial glucose metabolism in patients with PH.
No preview · Article · Jan 2013 · Journal of Nuclear Cardiology
[Show abstract][Hide abstract] ABSTRACT: The aim of this study is to evaluate the agreement between myocardial F-FDG PET imaging and cardiac magnetic resonance imaging (cMRI) in assessing cardiac function and relationship of cMRI late gadolinium enhancement (cMRI-LGE) and myocardial perfusion/metabolism pattern in patients with idiopathic dilated cardiomyopathy (IDCM).
Forty-two consecutive patients diagnosed with IDCM were enrolled. All patients underwent Tc-MIBI SPECT, gated F-FDG PET imaging, and cMRI within 3-7 days. Cardiac function parameters were calculated using PET and cMRI. The segments analysis was performed using a 17-segment model. Patterns of perfusion/metabolism were classified as normal, mismatch, mild-to-moderate match, and severe match, and cMRI-LGE was classified into 3 categories (non-LGE, mid-wall LGE, and transmural LGE).
The correlation between gated PET and cMRI was excellent for end-diastolic volume (EDV; r = 0.948, P < 0.001), end-systolic volume (ESV; r = 0.939, P < 0.001), and left ventricular ejection fraction (LVEF; r = 0.685, P < 0.001). EDV and ESV were underestimated, whereas LVEF was slightly overestimated by gated PET in comparison to cMRI. Perfusion/metabolism patterns varied in 3 different categories of non-LGE, mid-wall LGE, and transmural LGE (χ = 14.276, P < 0.001). Also, 71.0% (44/62) segments with mid-wall LGE had normal perfusion/metabolism patterns, and 75.9% (63/83) perfusion/metabolism mismatch segments were shown as non-LGE. The incidence of LGE was significantly higher in segments with severe match than the other 3 segment groups (χ = 112.53, P < 0.001).
There is an excellent agreement between gated PET and cMRI in assessment of cardiac function. LGE-cMRI is much more sensitive in detecting moderate fibrosis, while PET could detect more impaired but viable myocardium. Combining the 2 imaging modalities is useful for providing more comprehensive evaluations of myocardial injury in patients with IDCM.
No preview · Article · Dec 2012 · Clinical nuclear medicine
[Show abstract][Hide abstract] ABSTRACT: Rapid and timely diagnosis of pulmonary embolism (PE) and deep venous thrombosis (DVT) is important to improve patient outcome. The goal of this study was using (99m)Tc-chSZ21-F(ab)(2), F(ab)(2) fragment of anti-glycoprotein IIIa chimeric monoclonal antibody, to image experimental thromboembolism (DVT and PE) in dogs.
Flow cytometry assay and adenosine diphosphate (ADP) stimulated platelet aggregation was performed to determine the specificity and affinity of chSZ21-F(ab)(2) to the GPIIb/IIIa receptor on human or canine platelets. Both PE and DVT were induced in 12 beagle canines by catheter under X-ray direction. After (99m)Tc-chSZ21-F(ab)(2) injection,animals were imaged for up to 3hours then heparinized and sacrificed.
Specific binding of chSZ21-F (ab)(2) to GPIIb/IIIa on human or canine platelets was verified by flow cytometry assay. chSZ21-F (ab)(2) inhibited ADP induced platelet aggregation with a dose-dependent manner, the concentration required to inhibit 50% (IC(50)) of platelet aggregation was 11.6±7.9nM and 24.9±18.8nM for human and canine, respectively. In vivo, focal uptake was observed in planar images as early as 30min (DVT) and 60min (PE), and became clearer within 3hours after injection. Lesion-to-background ratio averaged 12.8 (PE-to-lung), 7.2 (DVT-to-blood), and 117.0(DVT-to-muscle), respectively.
These results suggested that (99m)Tc-chSZ21-F(ab)(2) with high DVT and PE uptake is a promising agent for imaging vascular thrombosis.
Full-text · Article · Sep 2012 · Thrombosis Research
[Show abstract][Hide abstract] ABSTRACT: This study measured glucose uptake in the right ventricle (RV) of patients with pulmonary hypertension and investigated the relationship to hemodynamics and survival. Myocardial 18F-fluorodeoxy-glucose (FDG) uptake was measured using single-photon positron emission tomography (SPECT) in 24 patients with idiopathic pulmonary arterial hypertension (IPAH) and 43 patients with congenital heart disease (CHD). In both IPAH and CHD-PAH, RV FDG uptake (RV/LV ratio) was associated with pulmonary vascular resistance (PVR). A second SPECT scan was performed in nine patients after 6 months treatment with sildenafil. PVR decreased from 1683±426 to 1207±383 dyn s(-1) cm(-5) (P < 0.05) and cardiac index improved from 2.2±0.2 to 2.8±0.5 L/min/m(2) (P < 0.01). RV/LV FDG uptake decreased from 1.28±0.32 before treatment to 0.99±0.23 (P < 0.05). Survival in the IPAH group with a baseline RV/LV FDG uptake greater than the median value of 1.20 was significantly lower than that of the group with RV/LV FDG uptake below 1.20 (log-rank test, P < 0.05). In contrast, baseline RV/LV FDG was of little informative value in CHD. FDG uptake by the RV reflects the severity of PVR in PAH. Increased RV FDG uptake is a marker of poor prognosis in IPAH and is reduced in patients receiving effective therapy. It could prove useful in the early clinical assessment of novel therapies for PAH.