Takatoshi Tsuda

Quantification of area and percentage of infarcted myocardium by single photon emission computed tomography with thallium-201: a comparison with serial serum CK-MB measurements.

In order to quantify the size of the infarcted myocardium, two kinds of data processing techniques were applied to single photon emission computed tomography (SPECT) with thallium-201 and its clinical reliability was evaluated by comparing it with the infarct sizing procedure with the serial serum creatine kinase-MB measurements in 14 patients with acute myocardial infarction. After maximum-count circumferential profile analysis, short axis images were reformatted into an unfolded surface map and a bull’s eye view map. The SPECT-determined infarct size was defined as the area or the percentage of hypoperfused myocardium of which the profile count was less than the mean minus 2SD derived from 8 normal subjects. The infarct area was calculated from the number of pixels with an abnormal count and expressed in an unfolded surface map. The percentage was calculated from the number of abnormal profile points and displayed in a bull’s eye view map. A high linear correlation was observed between the enzymatically determined infarct size and the infarct area or the percentage (r=.947, r=.872, respectively), despite underestimations in 2 patients with accompanying right ventricular infarction and overestimations in 2 patients with prior anterior infarction. Moreover, a close negative correlation was found between the left ventricular ejection fraction and the infarct area or the percentage (r=.836, r=.821, respectively).Thus, the semiautomatic techniques for processing thallium-201 SPECT images might contribute to the quantitative estimation and display of infarcted myocardium and have high clinical reliability.

Radioimmunoscintigraphy of human pancreatic carcinoma xenografts in nude mice with131I-labeled monoclonal antibody

Encouraged by reports of radioimmunoimaging of colorectal carcinomas1−3 and by examining an immunohistochemical report on resected pancreas cancer tissues4, we studied the diagnostic potential of radioimmunoimaging with the radioiodinelabeled monoclonal antibody to the surface antigen of a pancreas cancer cell line. A monoclonal antibody (MoAb; HC-1) to a human pancreas cancer cell line (HGC25)5 was labeled with radioiodine and injected into athymic nude mice implanted with human pancreas cancer cells. Antibody HC-1 was cleared from the circulation and accumulated significantly in the implanted tumor sites.

Scintigraphic imaging of a case of congenitally corrected transposition of the great vessels and an adult case of single atrium and single ventricle

We report on the clinical utility of radionuclide angiography and gated blood pool single emission computed tomography (gated blood pool SPECT) in two patients having congenital heart disease. Both conventional equilibrium radionuclide angiography and gated blood pool SPECT demonstrated the connection of the great vessels with both ventricles in a 15-year-old male patient with a congenitally corrected transposition of the great vessels. In particular, the latter procedure could provide very useful information about the ventricular morphology and inversion which is important for diagnosing this disorder. The second case is an extremely rare 42-year-old female patient with a single atrium and single ventricle. She underwent first-pass and multiple gated blood pool angiography from the anterior, right and left oblique views. The combination of these scintigraphic techniques revealed an insufficiency in anatomical correlations among the single atrium, atrioventricular valve, single ventricle and the great vessels in addition to the connection of superior vena cava with the single atrium, and the atrioventricular valve. Thus, conventional equilibrated angiography from multiple views and gated blood pool SPECT seems to be very reliable not only for anatomical evaluation but also for clinical course observation in patients with complicated congenital heart disease.

Dipyridamole‐provoked chest pain implies severe coronary artery disease in children

The diagnostic significance of dipyridamole‐provoked chest pain was studied in 17 children with severe coronary arterial stenotic lesions (CAL) complicated with Kawasaki disease. Although dipyridamole induced chest pain in seven patients (symptomatic group), 10 reported no pain (asymptomatic group). In the asymptomatic group, seven children had one vessel disease (1VD) of right coronary artery (RCA) and the other three had two vessel disease (2VD) involving the RCA and left anterior descending artery (LAD). Four multivessel disease patients, one three vessel disease (3VD) and three 2VD of LAD and RCA, and three 1VD of LAD, were symptomatic. In the thallium scans, all patients, except two of the asymptomatic group, showed perfusion abnormalities. In addition, the extent score of the symptomatic group was significantly worse than that of the asymptomatic group (P = 0.01). While only one in six of the asymptomatic group showed abnormal ST depression on treadmill exercise electrocardiography, all patients in the symptomatic group (P = 0.02) showed ischemic ST depression. These findings suggest that the occurrence of chest pain after medication with dipyridamole closely correlates with the severity of CAL in children.

Availability of111In-labeled platelet scintigraphy in patients with postinfarction left ventricular aneurysm

Eighteen patients with postinfarction left ventricular aneurysms (LVAs) were examined with Indium-111-labeled autologous platelet scintigraphy to identify intracardiac thrombi and to investigate the effect of antithrombotic agents on thrombogenesity within their LVAs. Left ventriculography (LVG), and two-dimensional echocardiography were also carried out to assess the diagnostic ability of the platelet imaging.Indium-111-platelet scintigraphy for the detection of LVA mural thrombi had a sensitivity of 60% and a specificity of 100%. Four of six patients with false-negative scintigraphic studies had been under antiplatelet therapy. Eight of the nine patients who had showed active platelet deposition on initial examination had not received antiplatelet therapy. Thereafter, five of these nine were treated with tichlopidine (300 mg/day) for 29.8±5.0 days. On the second platelet study, two had resolution and the other three had interruption of intra-aneurysmal deposition, which remained positive. In only one patient of the three, the third platelet study was performed after warfarin therapy. It took two weeks after beginning the therapy to completely interrupt platelet deposition within the LVA in this patient.ECG gated radionuclide ventriculography and Thallium-201-myocardial scintigraphy were also performed to assess left ventricular wall motion of left ventricular ejection fraction (LVEF) and myocardial blood perfusion.Thallium-201-SPECT showed apical or anteroapical perfusion defects and the radionuclide ventriculography correctly identified all 18 apical and anteroseptal aneurysms which were confirmed by LVG methods.The comparison between the thrombus positive group and the thrombus negative group was carried out on both the LVEF and the period from the last myocardial infarction to the initial platelet scanning study. There were no statistical differences in the LVEF and the interval (34.5±12.5% vs 37.3±14.6%, 39.6±52.6 days vs 89.6± 108.3 days) between the two groups.These results suggest that Indium-111-labeled platelet scintigraphy can be a reliable method for the identification of active left ventricular mural thrombi and a practical method of judging antiplatelet and anticoagulant therapy.

Autoradiographic analysis of [14C]deoxy-D-glucose in thyroid cancer xenografts: A comparative study with pathologic correlation

An experimental model of thyroid cancer was prepared for evaluating the accumulation of [14C]deoxy-D-glucose ([14C]DG) in thyroid cancer xenografts (AC2). A continuous cell line established from a biopsy specimen of a metastatic thyroid carcinoma possessed the ability to synthesize the cellular protein without increase in cell division after adding bovine TSHin vitro. The histological sections of the xenografts resected from the131I treated nude mice mainly consisted of structures showing follicular and trabecular growth. Immunohistochemically the cytoplasm of the tumor cells was positive for human thyroglobulin(hTg). These observations provide strong evidence that the AC2 cell originates in the thyroid follicular epithelium. By comparing autoradiographic accumulation patterns of [14C]DG and histopathological examinations, it was found that the uptake of [14C]DG was higher in the granulation tissues surrounding necrosis than in viable tumor cells of trabeculary growing and follicle forming tissues.It is suggested that the degree of [14C]DG content reflects not only tumor cell viability and proliferation but also the inflammatory and degenerative reaction accompanying tumor cell growth.

Quantification of antimyosin uptake and infarct size at various stages of myocardial infarction

We studied with quantitative techniques the clinical efficacy of indium-111 antimyosin at a later stage of myocardial infarction in 18 patients at various stages after infarction. Antimyosin accumulation was detected irrespective of infarct age and size and quantified as an infarct weight with a tomographic technique. Higher intensities in a planar image were observed in anterior Q wave infarct group (36 +/- 5 g) but not in inferior and non-Q wave anterior infarct groups because of the smaller infarct weights (8 +/- 3 g, 13 +/- 6 g, respectively). Infarct area calculated from thallium-201 tomography significantly correlated with left ventricular ejection fraction in both recent (less than 2 weeks) and older (2-week- to 6-month-old) infarct groups (r = -0.969, P less than 0.001; r = -0.860, P less than 0.001, respectively), whereas there was a significant negative correlation between infarct weight and left ventricular ejection fraction in the recent infarct group (r = -0.731, P less than 0.05) but not in the older infarct group. Thus, antimyosin tomography can detect myocardial necrosis with a high sensitivity regardless of infarct age, size, and location. However, the accumulation might be affected by infarct age and correspond to necrotic mass but not necessarily to infarct volume itself at a later stage probably because of the presence of necrosed and scarred tissues in infarcted myocardium.

In vitro andin vivo characterizations of established human follicular carcinoma cell line derived from thyroid cancer: A novel model for well-differentiated thyroid malignant tumor

A continuous cell line, named SMC R86 Fl, was established from a surgically resected primary thyroid lesion. The cell grew as an adhering monolayer with a doubling time of about 25 hours in modified Eagle’s medium supplemented with fetal bovine serum. When the cells were transplanted into athymic nude mice, tumors developed at the site of inoculation. The cells not only showed epithelial origin upon light and electron microscopic examination but also possessed a biosynthetic marker human thyroglobulin (hTg). In order to examine the iodide trapping ability of the xenografts, radioiodine at doses of 3.7 MBq was injected into the peritoneum of131I treated nude mice bearing xenografts at about 4 weeks after the cell inoculation. Judging from the results of scintigraphic, autoradiographic and biodistribution studies, viable tissue of the xenografts in the treated mice had the ability to trap radioiodine. Histological sections of the xenografts resected from the treated mice consisted of follicle-like and trabecular growing structures, and immunohistochemically the cytoplasm of the tissues was hTg positive. The cells possessed the ability to trap radioactive iodinein vitro under the control of TSH. In addition, the expression of iodinated 19S Tg in the cell cytoplasms in the monolayer cultures was revealed by immunoblotting and auto-radiographic assays. These observations provide strong evidence that the SMC R86 Fl cell line possesses well-differentiated properties of the malignant thyroid follicular epithelial cells.

Noninvasive evaluations of pulmonary circulation, cardiac function, and liver excreting rate at late follow-up following the modified Fontan operation

The purpose of this paper was to define the late postoperative pulmonary circulation and cardiac and liver functions after a modified Fontan operation by radionuclide studies. Eleven patients (5 with single ventricle and 6 with double outlet right ventricle) underwent a modified Fontan operation using a RA-PA anastomosis. These 11 patients ranging in age from 7 to 42 years (mean 17±10 years) were examined at 4.7–12.1 years (mean 8.6±2.4 years) postoperatively and compared with studies in 10 normal adults. Pulmonary circulation, cardiac function and liver excreting function were determined by intravenous administration of Tc-MAA, Tc-PYP, and Tc-PMT, respectively. No extrapulmonary radioactivity was detected by Tc-MAA lung perfusion in patients. Although the cardiac diastolic function of the patients remained normal, the systolic functions (EF=46.4±7.8%, 1/3EF=11.2±4.4%, PER=1.93±0.54/sec) of the patients were significantly decreased compared with those of normal controls (EF=54.7±4.7%, 1/3EF=21.7±2.1%, PER=2.91±0.4/sec), respectively. The mean level of MTT of the patients (9.4±2.7 minutes) was also significantly prolonged compared with that of normal controls (6.1±4.4 minutes). Some of these deteriorated parameters clearly related to higher age at operation and length of intervals since operation. These data suggest that the earlier surgical intervention by the Fontan operation is desired for the complex congenital cardiac anomalies.