[Myocardial imaging with 123I-MIBG and 201Tl].
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3-Iodobenzylguanidine↗
Biomedical subjects
H Bunko
Publications and source records attributed to H Bunko.
Dynamic acquisition with a three-headed SPECT system: application to technetium 99m-SQ30217 myocardial imaging.
A method for SPECT data acquisition, "continuous repetitive rotation acquisition," was developed with a high-sensitivity three-headed SPECT system. The method was applied to the dynamic imaging of 99mTc-SQ30217, a new myocardial imaging agent. After acquisition and reconstruction of SPECT data every minute, projection images at arbitrary intervals were used for tomographic reconstruction to determine the best timing of SPECT imaging in 99mTc-SQ30217. Based on a comparison of several possible acquisition intervals, SPECT data acquisition within 9 min after injection is recommended because of high myocardial uptake (myocardium-to-lung ratio, 2.83 +/- 0.42 (mean +/- s.e.m.) at 3-6 min) and relatively low hepatic uptake (myocardium-to-liver ratio, 0.85 +/- 0.13 at 3-6 min). The rate constant of the clearance of 99mTc-SQ30217 from the myocardium obtained by SPECT was: k1 = 0.249 +/- 0.050 per min (average half-life = 2.8 min) and k2 = 0.012 +/- 0.004/min (average half-life = 58 min). The continuous repetitive rotation acquisition SPECT study appears useful for imaging SQ30217 with its rapidly changing myocardial distribution.
Adult↗
[Lung ventilation imaging with TECHNEGAS: clinical study of lung deposition and ventilation/perfusion].
In order to optimize inhalation method for lung ventilation imaging with Tc-99m-gas (TECHNEGAS), relation between lung deposition of TECHNEGAS and inhalation method was evaluated. Submaximal inhalation with breath-holding (BH), continuous submaximal inhalation (C) and tidal inhalation (TV) were compared in 35 patients (36 studies) with various lung diseases. Mean lung deposition of TECHNEGAS was 6.6-7.4%/LD in BH group and was significantly higher than other groups of inhalation method (p less than 0.05-0.001). Lung deposition increased according to the times of inhalation in C group. TV group resulted in the lowest lung deposition which was same as 5 times of inhalation in C group. Lung/filter ratio (L/F) was highest in BH group. Image quality of TECHNEGAS was significantly better in BH group. Hot spot in central airway was seen in 15% of patients. All of them was in TV or C groups. In order to improve lung deposition and image quality of the TECHNEGAS, sufficient breath-holding was important. L/F seemed to be the index of effective inhalation of the TECHNEGAS. TV was suitable for poorly cooperative or dyspneic patients. TECHNEGAS was useful for evaluation of lung ventilation to provide good quality image with safety and simplicity.
Administration, Inhalation↗
[Myocardial perfusion imaging with 99mTc-SQ30217: application of three-headed SPECT system].
The early dynamic change of a new myocardial imaging agent, 99mTc-SQ30217, was investigated in SPECT study. A three-headed high sensitivity SPECT system was employed to evaluate the serial changes of accumulation pattern in the heart, lung and liver using a "continuous repetitive acquisition" mode. The myocardial activity reached a peak rapidly and decreased with rapid clearance rate. The analysis of myocardial clearance curve showed a T1/2 of 2.8 minutes (k1 = 0.25 +/- 0.12/min) in the rapid phase, and a T1/2 of 57 minutes (k2 = 0.012 +/- 0.011/min) in the slow phase. The tracer clearance in the lung was more rapid, while the hepatic uptake reached a peak approximately 10 to 15 minutes after injection. When the serial SPECT images were reviewed, the early 3-minute acquisition within 10 minutes after injection showed better image quality than the images obtained after 10 minutes. The hepatic activity did not obscure the infero-septal wall in the earlier images, but did in the images 10 minutes after injection. Thus, quick SPECT data acquisition seemed to be desirable for this agent. We concluded that 99mTc-SQ30217 was a promising radiopharmaceutical for myocardial perfusion imaging.
Aged↗
Whole-body distribution of iodine 123 metaiodobenzylguanidine in hypertrophic cardiomyopathy: significance of its washout from the heart.
Whole-body distribution of iodine 123 metaiodobenzylguanidine (123I-mIBG) was evaluated in 27 patients with hypertrophic cardiomyopathy (HCM). At 1 and 4 h after injection, anterior and posterior whole-body images were obtained with a dual-headed, camera-computer system. Patients were classified into three groups based on the septal wall thickness as determined by echocardiography: group 1 consisted of 7 patients with less than or equal to 15 mm septal thickness, group 2 included 12 patients with 16-19 mm septal thickness, and group 3 included 6 patients with greater than or equal to 20 mm septal thickness. Although the myocardial mIBG uptakes at 1 h were similar among these groups (1.84% +/- 0.19%, 1.95% +/- 0.38%, 1.98% +/- 0.57%, respectively; NS), mIBG washout from the heart in group 3 was faster than in groups 1 and 2 (31.5% +/- 13.0% vs. 15.8% +/- 11.0% (group 1, P less than 0.05), 17.6% +/- 7.3% (group 2, P less than 0.01)). There was a significant positive correlation between mIBG washout from the heart and septal thickness, with correlation coefficient r = 0.52 (P less than 0.01). The liver, lung, parotid gland, spleen and skeletal muscle showed similar mIBG uptake and washout among the three groups. We conclude from these data that mIBG washout from the heart in HCM was faster in patients with severe hypertrophy than in patients with mild to moderate hypertrophy, and hence it may be a useful parameter for evaluating the severity of altered adrenergic innervation and activities.
3-Iodobenzylguanidine↗
Error of uptake in dual energy acquisition with 201Tl and 123I labeled radiopharmaceuticals.
In myocardial scintigraphy, simultaneous injection of two radionuclides and dual energy acquisition are potentially useful in the assessment of regional perfusion and metabolism. The feasibility of dual radionuclide study with 201Tl and 123I labeled radiopharmaceuticals (meta-iodobenzylguanidine I 123, in this study) was investigated in phantoms and patients. The crosstalk of one radionuclide to the other pulse height window was defined as the ratio of the 201Tl count in the 123I and 201Tl windows, R[I/Tl], and the ratio of the 123I count in the 201Tl and 123I windows, R[Tl/I]. The ratios were determined in planar images and SPECT studies. In clinical studies with whole body scintigraphy (n = 8), the value of R differed significantly in various organs. In the SPECT study (n = 13), R was not uniform and varied with time and location, resulting in significant errors in uptake and regional count ratio. Thus, dual energy acquisition with 201Tl and 123I labeled radiopharmaceuticals is generally not recommended because of varying amounts of crosstalk interference. Possible solutions to this problem are discussed. The feasibility of dual radionuclide study must be confirmed in human as well as in phantom studies.
3-Iodobenzylguanidine↗
Quantitative analysis of 123I-meta-iodobenzylguanidine (MIBG) uptake in hypertrophic cardiomyopathy.
Myocardial scintigraphy with 123I-meta-iodobenzylguanidine (MIBG) and thallium-201 (201Tl) was performed in 29 patients with hypertrophic cardiomyopathy (HCM) using whole-body scintigraphy and single-photon emission computed tomography (SPECT). Nonhypertensive patients were classified into three groups according to the septal thickness determined by ultrasonography; group 1 (wall thickness less than 16 mm, n = 5), group 2 (from 16 to 20 mm, n = 12) and group 3 (greater than 20 mm, n = 4). The regional myocardial uptakes of both 201Tl and 123I-MIBG (percent of injected dose/cm3 myocardium) were higher in the more hypertrophic septa. However, when regional MIBG uptake at 3 hours was divided by the 201Tl uptake to calculate the MIBG uptake per unit of blood flow, the hypertrophic septa showed lower mean values--0.39 +/- 0.23 and 0.50 +/- 0.10 in groups 3 and 2, respectively (p less than 0.1 compared with 0.69 +/- 0.20 in group 1). The regional MIBG clearance rate in the septum was significantly higher in group 3 compared with group 1 (13.4 +/- 8.0%/hr versus 1.5 +/- 6.2%/hr, p less than 0.05). The uptake and 123I-MIBG clearance rate in the lateral wall showed a similar tendency. Myocardial uptake determined by whole-body scintigraphy was slightly increased in group 2 (3.5 +/- 0.6%, p less than 0.05) compared with group 1 (2.7 +/- 0.8%); however, it was lower in group 3 (2.7 +/- 0.4%). Myocardial 123I-MIBG distribution demonstrated various patterns in comparison with 201Tl distribution, suggesting that flow-independent changes in sympathetic innervation or activity may exist in patients with HCM.(ABSTRACT TRUNCATED AT 250 WORDS)
3-Iodobenzylguanidine↗
Shunt between right subclavian vein and the left heart in superior vena cava obstruction due to lung cancer.
A case in which there was a shunt between systemic veins and the left heart in superior vena cava syndrome due to lung cancer is reported. Superior vena cava syndrome developed one and a half years after right upper lobectomy with combined resection of thoracic wall. Radionuclide venography from the right antecubital vein showed immediate visualization of the left ventricle and aorta, before the right atrium and right ventricle were seen. In the superior vena cava syndrome due to a malignant tumor, this rare pathway as well as usual collaterals should be considered.
Carcinoma, Squamous Cell↗
Cardiac sarcoidosis demonstrated by Tl-201 and Ga-67 SPECT imaging.
Ga-67 and Tl-201 SPECT was performed to evaluate cardiac sarcoidosis in a 15-year-old boy. Tl-201 SPECT imaging showed decreased uptake in the inferior to lateral wall and Ga-67 accumulation in the area of decreased Tl-201 uptake. These findings suggested cardiac sarcoidosis, and cardiac biopsy confirmed this diagnosis. After corticosteroid therapy, myocardial uptake of Ga-67 disappeared and myocardial TI-201 uptake became more homogeneous.
Adolescent↗
Estimation of right ventricular pressure by 201Tl scintigraphy in paediatric cardiac disease.
To estimate right ventricular overload in paediatric cardiac disease, 201Tl scintigraphy was used to quantify right ventricular uptake. Six methods for calculating the 201Tl right-to-left ventricular uptake ratio (TRL) were compared, based on the location of regions of interest (ROIs), use of total count or mean count density, and the ROI-based method or profile method. When the TRL was compared with the right-to-left ventricular peak systolic pressure ratio (RVP/LVP), the mean count density method using entire right and left ventricular ROIs seemed to be appropriate, considering its simplicity, reproducibility and regression line. The linear regression line was RVP/LVP = 1.15 x TRL - 0.13 (n = 15, P = -0.0001), and RVP(mm Hg) = 162 x TRL - 33 (n = 15, P = 0.0001). In four patients with pulmonary stenosis, the changes of TRL were in good agreement with the right ventricular pressure changes after percutaneous balloon valvuloplasty. Thus, evaluation of thallium scintigraphy using this quantitative method can be a simple and effective way to evaluate patients with right ventricular pressure overloading.
Adolescent↗
[Washout rate in patients with hypertrophic cardiomyopathy and hypertensive cardiac hypertrophy].
The present study was performed to clinically clarify the pathogenesis of hypertensive cardiac hypertrophy (HT) and hypertrophic cardiomyopathy (HCM). Exercise thallium-201 (Tl-201) myocardial scintigraphy using a bicycle ergometer was performed for controls, HT and HCM. The scintigrams were evaluated by the circumferential profile analysis. Furthermore, the changes in Tl-201 dynamics in exercise Tl-201 scintigraphy with verapamil injections were examined in these three groups. Analysis of exercise Tl-201 scintigraphy without verapamil injections showed that the initial uptake did not differ among the three groups, but the washout rate three hours after the Tl-201 injections (WR3) did differ among the three groups. Although the WR3 of HT did not differ from that of the controls, the WR3 of HCM was lower than that of the controls. The WR3 with and without verapamil were compared. Although the WR with verapamil injections equalled that without verapamil injections in the controls and HT, the WR3 with verapamil injections decreased more than did that without verapamil injections in HCM. As an index of great and rapid changes in circulation, the washout rate one hour after the Tl-201 injection (WR1) was calculated. The WR1 without verapamil did not differ among the three groups and did not differ from that with verapamil injections in each group. These results suggest that Tl-201 dynamics of HT differ from those of HCM and lowering of the WR3 in HCM may not be caused by disturbance in the microcirculation, but rather by disturbance of Tl-clearance through the cell membrane and its cytoplasm.
Cardiomegaly↗
[Evaluation of factor analysis and other functional images in exercise gated blood-pool study].
Factor analysis, a new method of functional imaging, has been applied to cardiovascular nuclear medicine. Because of the difficulty of its interpretation, it has not been popular as a method for detecting abnormal wall motion. The purpose of this study was to evaluate the usefulness of factor analysis in exercise gated blood-pool study in patients with ischemic heart disease. In our factor analysis, left ventricular region of interest (LVROI) was extracted to exclude the surrounding radioactivities. The new method was compared with 1) the conventional factor analysis using whole region (whole ROI method), and with 2) the other functional images, i.e. stroke volume, ejection fraction and phase images. At first we tried 3-factor analysis of the LVROI method, which resulted in many uninterpretable factors. Whereas in 2-factor analysis no uninterpretable factors were extracted. In comparison with cine-mode display, the LVROI method with 2-factor analysis showed the best sensitivity (85%) and specificity (100%). In exercise gated blood-pool study, it became easier to detect abnormal wall motion by comparing the factor image at exercise with resting image. In conclusion, the 2-factor analysis using the LVROI method greatly improved the limitation of conventional factor analysis, and will be useful in detecting wall motion abnormality in patients with ischemic heart disease.
Adult↗
[Myocardial viability evaluation by nuclear cardiology].
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Deoxyglucose↗
[Evaluation of hypertrophic cardiomyopathy with 123I-metaiodobenzylguanidine].
Single-photon emission computed tomography was performed in 29 patients with hypertrophic cardiomyopathy (HCM) using 123I-metaiodobenzylguanidine (MIBG). Segmental myocardial uptake of MIBG and 201T1 was calculated in 21 patients with primary HCM without history of hypertension. Septal thickness was measured by echocardiography and the relationship to septal MIBG uptake was studied. Initial MIBG uptake and 201T1 uptake showed positive correlation with the septal thickness (R = 0.581, p = 0.0058 and R = 0.677, p = 0.0007). When the septal MIBG uptake was divided by the corresponding 201T1 uptake (MIBG/T1), both the early and delayed MIBG/T1 showed negative correlation with the septal thickness (R = -0.485, p = 0.0255 and R = -0.535, p = 0.0125). Significant positive correlation was observed between septal MIBG clearance and the thickness (R = 0.510, p = 0.0182). In patients with severe septal hypertrophy (greater than 20 mm), the MIBG clearance was significantly higher compared with less hypertrophic (less than or equal to 20 mm) group (13.4 +/- 8.0%/hr vs. 3.2 +/- 4.7%/hr, p = 0.0028). Thus, MIBG was useful for the evaluation of sympathetic innervation and activity in HCM. The MIBG clearance and uptake in conjunction with 201T1 study seemed to reflect the severity of hypertrophy in HCM.
3-Iodobenzylguanidine↗
[A three-headed SPECT system with high resolution and high sensitivity: application to myocardial imaging].
A three-headed single-photon emission computed tomography (SPECT) system was developed, and the fundamental SPECT performance and clinical applications were investigated. The full width at half maximum (FWHM) of the SPECT system is 10.8 mm at the center of rotation with a radius of 20 cm. In clinical applications, 201Tl myocardial images with the three-headed system demonstrated a distincter and thinner myocardium compared to those with the dual-headed system. The right ventricular wall was observed even in patients without right ventricular overload. Owing to both the increased sensitivity and resolution, the three-headed system has high performance capability in clinical use such as ECG-gating and dynamic studies.
Coronary Disease↗
[Angiotensin II-induced hypertension chemotherapy of bone and soft-tissue sarcomas].
We treated 14 patients with high grade sarcomas by angiotensin II-induced hypertension chemotherapy. The chemotherapy protocol described by Rosen was selected according to histological classification of sarcomas (small cell sarcoma, spindle cell sarcoma, pleomorphic sarcoma). The level of angiotensin-induced hypertension was one and half times as high as blood pressure at rest. Induced hypertension was maintained for 30-60 minutes. In three cases of 5 primary osteosarcomas, induced hypertension resulted in the increase of tumor stain and/or vascularity angiographically, and chemotherapeutic effects were CR or PR. The six cases with soft-tissue sarcomas were 2 cases each of CR, PR, and NC. The decrease of relative tumor blood flow under the condition of angiotensin II-induced hypertension was detected in 5 cases of 6 soft-tissue sarcomas by 133Xe clearance method. In the case of rhabdomyosarcoma, the decrease of tumor stain and vascularity by induced hypertension was observed on angiogram. As the side effects accompanying induced hypertension, nausea and chest oppression were noted in 2 cases, respectively. In this study it was suggested that angiotensin II-induced hypertension chemotherapy was effective for osteosarcoma, but that it might be ineffective for soft-tissue sarcomas.
Adolescent↗
[Evaluation of ischemia by exercise stress Tl-201 myocardial SPECT in silent and symptomatic ischemia].
Forty patients with ischemic heart disease confirmed by coronary arteriography were performed Tl-201 stress myocardial scintigraphy using SPECT. Fifteen patients had anginal attack during exercise Tl-201 myocardial perfusion study (symptomatic group), and 25 patients had horizontal or downsloping ST segment depression more than 0.1 mV without angina (asymptomatic group). The washout maps were derived from circumferential profile analyses of tomographic short-axis slices, and the data were plotted as a bull's eye map. The patient's washout map was compared with the lower limit of normal (mean--2 SD), and the extent and severity scores were calculated. On visual analysis 87% (13/15) of symptomatic patients showed redistribution, while only 56% (14/25) of asymptomatic patients showed redistribution (p less than 0.05). The extent score was significantly higher in the symptomatic group than in asymptomatic group (37.2 + 23.6 vs. 19.6 + 20.8, p less than 0.05), but severity score was slightly higher in symptomatic group (56.1 + 59.4 vs. 30.0 + 54.8, NS). In conclusion, symptomatic ischemia may be more severe than asymptomatic one and the degree of ischemia may be one of the factors that determine the presence of angina during ischemia.
Adult↗
[Evaluation of ischemic heart disease by thallium-201 washout-rate map using SPECT].
In thallium-201 myocardial perfusion scintigraphy, washout rate (WR) has been used for the evaluation of the severity of ischemic heart disease (IHD). The WR was calculated from the polar map (Bull's-eye display) of myocardial perfusion using SPECT. To analyze the abnormality of WR map, we computed the extent and severity scores of WR. Applications of two types of standards, absolute and relative standards from control group (n = 16), were compared. The multiple regression analysis showed that the global WR was a function of the severity of coronary artery stenosis and exercise level, i.e. WR (%) = -2.38 X (number of stenotic artery) + 0.093 X (rate-pressure product/100) + 19.7 (n = 62, r = 0.63). Thus in evaluating the severity of IHD by absolute WR, the correction of WR was necessary according to the exercise level. Whereas, to evaluate the score of WR abnormality in polar map, the relative standard separated each group with different number of stenotic artery better than absolute standard did. In conclusion, calculation of WR score from relative standard is recommended for the analysis of polar WR map, although absolute global WR is useful for the evaluation of severity of coronary artery disease.
Coronary Disease↗