Improved accuracy in estimation of left ventricular function parameters from QGS software with Tc-99m tetrofosmin gated-SPECT: a multivariate analysis.

The original publication is available at www.springerlink.com authorThe purpose of this study was to verify whether the accuracy of left ventricular parameters related to left ventricular function from gated-SPECT improved or not, using multivariate analysis. METHODS: Ninety-six patients with cardiovascular diseases were studied. Gated-SPECT with the QGS software and left ventriculography (LVG) were performed to obtain left ventricular ejection fraction (LVEF), end-diastolic volume (EDV) and end-systolic volume (ESV). Then, multivariate analyses were performed to determine empirical formulas for predicting these parameters. The calculated values of left ventricular parameters were compared with those obtained directly from the QGS software and LVG. RESULTS: Multivariate analyses were able to improve accuracy in estimation of LVEF, EDV and ESV. Statistically significant improvement was seen in LVEF (from r = 0.6965 to r = 0.8093, p < 0.05). Although not statistically significant, improvements in correlation coefficients were seen in EDV (from r = 0.7199 to r = 0.7595, p = 0.2750) and ESV (from r = 0.5694 to r = 0.5871, p = 0.4281). CONCLUSION: The empirical equations with multivariate analysis improved the accuracy in estimating LVEF from gated-SPECT with the QGS software

A compartment model analysis for investigation of myocardial fatty acid metabolism in patients with hypertrophic cardiomyopathy

This is a non-final version of an article published in final form in Okizaki, Atsutaka ; Shuke, Noriyuki ; Sato, Junichi ; Sasaki, Tomoaki ; Hasebe, Naoyuki ; Kikuchi, Kenjiro ; Aburano, Tamio, A compartment model analysis for investigation of myocardial fatty acid metabolism in patients with hypertrophic cardiomyopathy, Nuclear Medicine Communications 28(9), SEP 2007, pp. 726-735 authorObjective: The purpose of this study was to investigate the myocardial fatty acid metabolism in patients with hypertrophic cardiomyopathy (HCM) from dynamic SPECT through a compartment model analysis. Methods: Twenty-four normal controls, 7 patients with left ventricular hypertrophy (LVH) due to essential hypertension (eHT), and 30 patients with HCM were studied. I-123 BMIPP and Tc-99m tetrofosmin SPECT were performed. All the myocardium was divided into 13 segments, and totally 390 segments of HCM were categorized into early, moderately and severely advanced HCM segments, based on these SPECT imaging. By using the myocardial and blood pool time-activity curves, BMIPP pharmacokinetics was analyzed through a 2-compartment model. We defined k1 and k2 as influx and outflux rate constants between blood and myocardial reversible component, k3 as specific uptake rate constant between myocardial reversible and irreversible compartments. Results: The averages of k3 in HCM were higher than in normal. In contrast, the averages of k1/k2 in HCM were lower than in normal, and gradually decreased with progression of HCM. There are no significant differences in these indexes between normal controls and patients with LVH due to eHT. Conclusion: k3 might be a sensitive predictor for early detection of HCM, and k1/k2 could be a useful index to evaluate its progression. A mathematical compartment model analysis with BMIPP SPECT study might be useful not only for identification of HCM in very early stage, but also for evaluation of the progression of HCM

Estimation of fractional liver uptake and blood retention of 99mTc-DTPA-galactosyl human serum albumin: an application of a simple graphical method to dynamic SPECT.

This is a non-final version of an article published in final form in Shuke, Noriyuki ; Aburano, Tamio ; Okizaki, Atsutaka ; Zhao, Chunlei ; Nakajima, Kenichi ; Yokoyama, Kunihiko ; Kinuya, Seigo ; Watanabe, Naoto ; Michigishi, Takatoshi ; Tonami, Norihisa, Estimation of fractional liver uptake and blood retention of 99mTc-DTPA-galactosyl human serum albumin: an application of a simple graphical method to dynamic SPECT, Nuclear Medicine Communications 24(5), MAY 2003, pp. 503-511 authorThe objective of this study was to investigate clinical utility of a graphical method for estimating liver uptake and blood retention of 99mTc-DTPA-galactosyl human serum albumin (99mTc-GSA; DTPA is diethylenetriaminepentaacetic acid) using dynamic single photon emission computed tomography (SPECT) data. When considering the kinetics of 99mTc-GSA, if it is assumed that (1) 99mTc-GSA distributes only between blood and liver, and (2) no metabolism of 99mTc-GSA occurs during the observation period, a plot of liver counts versus cardiac blood pool counts should, theoretically, be a straight line. From the slope and y intercept of a regression line, coefficients for converting count based liver and blood pool data to the per cent injected dose (%ID) can be calculated. The applicability of this method was tested on dynamic SPECT data from 30 patients with liver dysfunction. To validate this method, plasma concentrations (%ID/ml plasma) at 6, 15 and 30 min after the injection were estimated by this method and compared with the measured ones. To investigate the clinical significance of the per cent liver uptake, the value obtained by this method was compared with the results of conventional liver function tests, including serum albumin, the hepaplastin test, prothrombin time and indocyanine green clearance. In every data set, a plot of liver counts to cardiac blood pool counts was fitted well by a straight line (P<0.00001). Estimated plasma concentrations by this method showed good correlation with the measured ones at 6, 15 and 30 min after the injection (r = 0.748, 0.838, 0.875, respectively; P<0.0001). The liver uptake determined by this method showed good correlation with the results of conventional hepatic function tests (P<0.002). The graphical method could provide an accurate estimate of %ID of 99mTc-GSA in blood without the need for blood sampling. The liver uptake determined by this method could be a simple but useful quantitative indicator of hepatic function

Optimization of the uptake method for estimating renal clearance of 99mTc mercaptoacetyltriglycine

This is a non-final version of an article published in final form in Zhao, Chunlei ; Shuke, Noriyuki ; Okizaki, Atsutaka ; Yamamoto, Wakako ; Usui, Koki ; Kikuchi, Kenjiro ; Kaneko, Shigeo ; Yachiku, Sunao ; Sasajima, Tadahiro ; Aburano, Tamio, Optimization of the uptake method for estimating renal clearance of 99mTc mercaptoacetyltriglycine, Nuclear Medicine Communications 25(2), FEB 2004, pp. 159-166OBJECTIVE: To improve the estimation of 99mTc mercaptoacetyltriglycine clearance in the renal uptake method by optimizing the conditions of renal depth, background, threshold for renal boundary determination, and time interval for integrating renal counts. METHODS: Dynamic renal imaging was performed in 232 patients with dual energy window acquisition (main, 140 +/- 14keV; sub, 122.5 3.5keV). For drawing renal regions of interest (ROIs), cut-off methods with 50% and 70% of the highest renal pixel counts were used. For drawing the backgrounds, circumferential and lateral-inferior quadrant peri-renal ROIs were used. For setting the time interval, periods of 1-2, 1-2.5, 1.5-2.5, 1.5-3 and 2-3 min post-injection were used. For determining renal depth, three methods of a theoretical exponential function using scatter fraction, Tonnesen's formula, and linear combination of scatter fraction and Tonnesen's formula were used. The scatter fraction was calculated using the counts in renal ROIs in the two energy windows. Using every combination of these conditions, renal uptake was calculated. As a reference, one-sample clearance was calculated from a blood sample taken at 30 min post-injection following Bubeck's formula. According to the methods for estimating renal depth, three non-linear regression models were derived to convert renal uptake to clearance. Using one-sample clearance and integrated renal counts as dependent and independent variables, data were fitted to the models to determine the necessary constants. The correlations between the model estimated clearances and one-sample clearance were investigated. RESULTS: One-sample clearance ranged from 11 to 404 ml x min(-1) per 1.73 m2. More than half of the regression using renal depth determined by the scatter fraction alone failed to converge. Among the successfully converged regressions, all model estimated clearances showed significant correlations (P<0.01) with one-sample clearance. The best correlation was observed in the model using renal depth determined by the combination of scatter fraction and Tonnesen's formulas, renal ROIs by 50% cut-off, lateral-inferior background and time interval of 2-3 min (r=0.898, P<0.001). CONCLUSION: The renal uptake method for estimating the clearance of mercaptoacetyltriglycine can be improved by the processing conditions proposed here

Impaired cardiac sympathetic nerve function in patients with Kawasaki disease: comparison with myocardial perfusion

This is a non-final version of an article published in final form in Zhao, Chunlei ; Shuke, Noriyuki ; Yamamoto, Wakako ; Okizaki, Atsutaka ; Sato, Junichi ; Kajino, Hiroki ; Fujieda, Kenji ; Aburano, Tamio, Impaired cardiac sympathetic nerve function in patients with Kawasaki disease: comparison with myocardial perfusion, Pediatric research 57(5 pt1), 2005, pp. 744-748Kawasaki disease (KD) is a leading cause of CAD in children. The impairment of cardiac sympathetic nerve function (CSNF) in the adult patients with coronary artery disease (CAD) could often be seen. However, little is known concerning the impairment of CSNF in KD patients. We investigated CSNF and its relationship with myocardial perfusion in KD patients. Eleven children with KD and 4 controls were studied with 123I-metaiodobenzylguanidine (MIBG) and stressed 201Tl single photon emission computed tomography. By the findings on coronary artery angiography (CAG), the patients were divided into 2 groups: A, without stenosis; B, with significant stenosis and/or old myocardial infarction. CSNF was evaluated from the uptake of 123I-MIBG. While myocardial perfusion was evaluated from 201Tl uptake. The numbers of patients in the groups A and B were 7 and 4. Perfusion defect was found in 0, and 2 patients in group A (0%), and B (50%). 123I-MIBG defects were found in 1 and 4 patients in the group A (14%) and B (100%). There were excellent concordances between the finding of 201Tl and 123I-MIBG in group A. While in group B, the coronary territories with 123I-MIBG defects were significantly more than those with perfusion defects (p < 0.05). In KD patients, the impairment of CSNF might be subsequent to coronary artery stenosis and was more severe than the injury of myocardial perfusion