Problems of [S-methyl-11C]-L-methionine as a protein synthesis marker in the pancreas.

To evaluate the possibility of [S-methyl-11C]-L-methionine as a protein synthesis marker in the pancreas, the effect of various labeling positions in the accumulation and metabolism of 14C-labeled L-methionines (S-methyl-14C, 1-14C and 3,4-14C) was studied. In mouse biodistribution studies, the methionines showed differing patterns of labeling position-dependent pancreatic accumulation. In the case of [S-methyl-14C]-L-methionine, protein-incorporation and methyl-transformation equally served as retention mechanisms in the pancreas, indicating [S-methyl-11C]-L-methionine's unsuitability as a pancreatic protein synthesis marker.

[Clinical trial of 111In-antimyosin antibody imaging: (4). Effect of reperfusion in acute myocardial infarction].

Effects of reperfusion by intra-coronary thrombolysis (ICT) or percutaneous transluminal coronary angioplasty (PTCA) on the myocardial imaging using 111In-labeled antimyosin monoclonal antibody Fab (In-AM) were studied. Reperfusion by ICT or PTCA was done in 16 patients (reperfusion group) and recanalization was seen in 14. Positive images were obtained in 28 of 30 patients (93%) with acute myocardial infarction (onset to imaging: 9.

[A study of renal leak of 99mTc-DMSA in maleate-treated rats by factor analysis].

To elucidate renal leak of 99mTc-dimercaptosuccinic acid (99mTc-DMSA) in maleate-treated rats, plasma amino acid levels and urinary excreted % doses of 99mTc-DMSA and 131I-ortho-iodohippurate (131I-OIH) were studied by factor analysis. 0.4 m mol of Na-maleate dissolved in 2 ml of saline was intraperitoneally injected twice at an interval of 20 hours.

Indium-111-antimyosin antibody imaging for detecting different stages of myocardial infarction: comparison with technetium-99m-pyrophosphate imaging.

The diagnostic value of 111In-antimyosin (AM) imaging for identifying myocardial infarction was evaluated in comparison with 99mTc-pyrophosphate (PPi) imaging. Twenty-four patients with various stages of myocardial infarction, ranging from three days to nine months after the onset of infarction, underwent both AM and PPi scans. Of 26 infarct lesions AM scan identified 22 (85%), while PPi scans detected 10 (38%) (p less than 0.

[Assessment of resting thallium-201 reinjection after stress-delayed Tl imaging (I): Comparison with 24-hour scan and regional wall motion].

Clinical value of resting reinjection of 1 mCi (37 MBq) of Tl after stress-delayed scan was assessed in comparison with 24 hr delayed scan and regional wall motion (RWM) in 37 patients with coronary artery disease. Of 101 segments with initial perfusion abnormality, concordant findings were observed after Tl reinjection in 67 segments (66%). But redistribution (RD) after Tl reinjection was observed in 19 of the 52 persistent defect (PD) segments (37%), and complete RD was observed 15 of the 43 segments (35%) where 3 hr scan showed incomplete RD.

Evaluation of glucose transport in malignant glioma by PET.

Using dynamic PET mode and 18FDG, glucose transport in patients with gliomas were investigated. The values for transfer rate constants k1*, k2*, k3*, and glucose consumption were found to be low in the low-grade glioma as compared to those of the high-grade glioma and the contralateral cerebral cortex. The differences were statistically significant with the exception of k2*.

Temporal changes in accumulation of N-isopropyl-p-iodoamphetamine in human brain: relation to lung clearance.

Temporal changes in brain uptake of 123I-labeled N-isopropyl-p-iodoamphetamine (IMP) were studied by means of a multi-detector single photon emission computed tomography (SPECT) scanner. Serial dynamic SPECT scan was performed for 50 min following an i.v.

[Usefulness of exercise Tl-201 myocardial scintigraphy: comparison with positron emission tomography].

To evaluate the usefulness of exercise Tl-201 myocardial scintigraphy, we performed positron emission tomography and conventional exercise Tl-201 emission computed tomography (ECT) in 33 patients with old anterior myocardial infarction (Q-MI: 24, non Q-MI: 9). N-13 ammonia was used as a blood flow tracer, and imaging was performed at rest and after multistage, symptom-limited ergometer exercise. After the administration of F-18 deoxyglucose (FDG) at rest in the fasting state, metabolic imagings were performed to evaluate regional exogenous glucose utilization.

A new zinc-62/copper-62 generator as a copper-62 source for PET radiopharmaceuticals.

A new 62Zn/62Cu generator system was designed to provide a readily available 62Cu source for positron emission tomographic radiopharmaceuticals, based on the differences of complex formation between Zn and Cu. Noncarrier added 62Cu was selectively eluted as a glycine complex from 62Zn-adsorbed cation-exchange resin (CG-120, Amberlite), when a glycine solution (200 mM) was used as the eluant. The elution efficiency and radionuclidic purity of 62Cu were 70% and greater than 99.

Quantitative analysis of regional wall motion by gated myocardial positron emission tomography: validation and comparison with left ventriculography.

Electrocardiographically gated positron emission tomography (ECG-gated PET) with [13N] ammonia was used to assess regional myocardial wall motion of left ventricle (LV) based on a nongeometric method in nine healthy volunteers and 16 patients with coronary artery disease (CAD). Three transverse sections (upper, middle, and lower) with 16-mm intervals at end-diastole (ED) and end-systole (ES) were analyzed. The LV wall was divided into eight segments with every 30 degrees from septal wall to lateral wall.

Silent myocardial ischemia in patients with myocardial infarction: evaluation with positron emission computed tomography.

To evaluate myocardial blood flow and glucose utilization, N-13 ammonia and F-18 deoxyglucose positron emission tomography were performed in 33 patients with myocardial infarction. The N-13 ammonia study was performed at rest and during supine exercise, and the F-18 deoxyglucose was done at rest after greater than or equal to 5 hours of fasting. Based on angina, exercise-induced hypoperfusion, and deoxyglucose uptake, 3 groups of patients were classified; 10 patients in group I (neither angina nor exercise induced hypoperfusion), 8 patients in group II (painless exercise-induced hypoperfusion) and 15 patients in group III (anginal patients with/without exercise-induced hypoperfusion).

[Assessment of myocardial viability by quantitative analysis of stress Tl-SPECT--comparison with FDG-PET].

Stress Tl-201 tomography (SPECT) is widely used for evaluating myocardial viability. To assess its value, redistribution (RD) on SPECT was compared with metabolic imaging using FDG. Thirty patients with coronary artery disease underwent stress-3 hour Tl-201 SPECT and PET using N-13 ammonia and FDG.

Positron emission tomography using fluorine-18 deoxyglucose in evaluation of coronary artery bypass grafting.

To assess the clinical value of positron emission tomography (PET) in the evaluation of coronary artery bypass grafting (CABG), PET perfusion and metabolic imaging using nitrogen-13 ammonia and fluorine-18 deoxyglucose (FDG) was performed before and 5 to 7 weeks after CABG in 22 patients with coronary artery disease. Postoperative improvement in hypoperfusion was observed more often in the metabolically active segments (62%) than in the inactive segments (27%) on the preoperative PET study (p less than 0.05).

Glucose metabolism and rate constants in Alzheimer's disease examined with dynamic positron emission tomography scan.

Glucose metabolic rate constants in patients with Alzheimer's disease were analyzed using dynamic positron emission tomography with [18-F] fluoro-2-deoxyglucose (FDG). The cerebral metabolic rate of glucose (CMRG) was calculated using obtained rate constants, as well as the autoradiographic method. The half-life and distribution volume of FDG between the blood and the brain tissue were also calculated from obtained metabolic rate constants.

[Pathophysiology of dementia and medical imaging].

Dementia is not a particular disease but a clinical syndrome based on the subjective and objective symptoms. Morphological imaging modalities such as X-ray computed tomography (CT) and magnetic resonance imaging (MRI) can accurately identify those which can be treated. Functional imaging techniques such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT) can visualize the regional decrease of neuronal function as mapping of cerebral blood flow and metabolism.

[Crossed "cerebral" diaschisis? Seven cases with unilateral cerebellar vascular lesion which showed decreased perfusion in the contralateral cerebral cortex].

In 7 cases with unilateral cerebellar vascular lesion, decreased perfusion was observed in the contralateral cerebral cortex by single photon emission computed tomography (SPECT) with I-123 labeled N-isopropyl-p-iodoamphetamine (IMP). These cases had symptoms due to cerebellar lesions but did not show any cerebral cortical symptoms. Reduction of cerebral cortical perfusion appeared on more than 25 days after the onset of CVA, did not correlate with morphological changes by cranial X-ray computed tomography and digital subtraction angiography in acute phase, and was persistent or irreversible later.

[Clinical trial of 111In-antimyosin antibody imaging: (3) Comparison with 99mTc-pyrophosphate imaging].

Clinical value of 111In-antimyosin monoclonal antibody F ab (AM) was compared with 99mTc-pyrophosphate (PYP) in 13 patients with myocardial infarction and 3 patients with myocarditis. Following PYP injection, PYP imaging was performed 3 hours later. Immediately after PYP imaging, AM was administrated and AM images were obtained 48 hours later.

Value of rest-stress myocardial positron tomography using nitrogen-13 ammonia for the preoperative prediction of reversible asynergy.

To determine the predictive value of stress [13N]ammonia positron emission tomography (PET) for reversible ischemia, 31 patients with coronary artery disease underwent rest-stress [13N]ammonia PET before and after coronary artery bypass surgery. The circumferential profile analysis was applied to determine the presence of transient defect (TD) and persistent defect (PD) preoperatively, and the fate of perfusion abnormality and asynergy after the surgery was assessed. Preoperative PET demonstrated 100 segments with perfusion abnormalities, including 69 TD and 31 PD.

[The effect of glycerol on regional cerebral blood flow, blood volume and oxygen metabolism].

Using positron emission tomography with 15O-labelled CO2 O2 and CO gases, the effects of glycerol on regional cerebral blood flow (CBF), blood volume (CBV) and oxygen metabolism (CMRO2) were investigated in 6 patients with meningioma accompanying peritumoral brain edema. The same study was done in 5 normal volunteers. The changes of blood gases, hematocrit and hemoglobin were also examined.

Multidetector SPECT scanner for brain and body: system performance and applications.

A multidetector whole-body single photon emission computed tomography (SPECT) scanner has been developed for high-resolution dynamic SPECT imaging. The scanner consists of three detector rings with 128 NaI crystals (14 x 26 x 30 mm) in each ring, providing three tomographic images at 30 mm intervals. This system uses a rotation of collimator around the patient combined with the detector rotation for fine data sampling.

[Clinical trial of 111In-antimyosin antibody imaging: (2). Imaging of myocardial infarction and myocarditis].

A new scintigraphic method to detect myocardial necrosis has been developed using antimyosin monoclonal antibody F ab labeled with indium-111 (111In-antimyosin). We investigated 111In-antimyosin scintigraphy in 35 patients with myocardial infarction, 5 patients with myocarditis and 3 patients with angina pectoris. 111In-antimyosin F ab was administered iv and antimyosin images were recorded by planar and single photon emission computed tomography (SPECT) 48-72 hrs after injection.

[Clinical trial of 111In-antimyosin antibody imaging: (1). Assessment of tracer kinetics and imaging time].

The human clinical trial of 111In-antimyosin antibody was performed in 20 patients with various cardiac disorders to assess its safety and tracer kinetics and to determine the optimal imaging time. There were no side effects derived from this tracer after its administration. The skin test and the antimurine antibody were both negative in any patient.

Value of stress thallium-201 emission tomography for predicting improvement after coronary bypass grafting and assessing graft patency.

To examine the value of stress and redistribution thallium-201 single photon emission computed tomography (SPECT) for predicting improvement after coronary artery bypass grafting (CABG) and for assessing graft patency, 17 patients underwent SPECT before and after CABG. Preoperatively, 16 patients (94%) showed reversible ischemia with redistribution, and defect score decreased from 16.4 +/- 7.

Regional cerebral blood flow and oxygen metabolism in normal pressure hydrocephalus after subarachnoid hemorrhage.

To clarify the pathophysiology of normal pressure hydrocephalus (NPH) after subarachnoid hemorrhage, the authors measured cerebral blood flow (CBF), cerebral oxygen metabolic rates (CMRO2), the cerebral oxygen extraction fraction (OEF), and cerebral blood volume (CBV) in eight normal volunteers, six SAH patients with NPH, and seven patients without NPH by 15O-labeled gas and positron emission tomography (PET). In the NPH group, PET revealed a decrease in CBF in the lower regions of the cerebral cortex and a diffuse decrease in CMRO2. The decrease in CBF in the lower frontal, temporal, and occipital cortices was significantly greater in the NPH than in the non-NPH group.

[Serial assessment of cardiac function during and after exercise by an ambulatory ventricular function monitor (VEST)].

Cardiac function was serially assessed during and after exercise by an ambulatory ventricular function monitor (VEST) in 31 patients who received coronary angiography. Based on the study of fluctuation during the baseline recording, greater than or equal to 6% change in ejection fraction (EF) was considered significant. The serial changes in EF during exercise was divided into 5 types, including continuous increase (type A), initial increase but return to the baseline (type B), no change (type C), initial increase but later decrease below the baseline (type D), and continuous decrease (type E).