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Background: Diabetes is frequently accompanied by chronic kidney disease, and both diabetes and chronic kidney disease are risk factors for ischemic heart disease; however, cardiac risk among diabetic patients with mild renal dysfunction has not been analyzed in detail. The present study investigates how myocardial perfusion imaging (MPI) contributes to the risk stratification of diabetic patients with mild renal dysfunction who are asymptomatic for cardiac diseases., Patients and Methods: Among 513 asymptomatic patients with type 2 diabetes in the Japanese Assessment of Cardiac Events and Survival Study 2 (J-ACCESS) database, we selected 286 with estimated glomerular filtration rates (eGFR) of at least 45 ml/min/1.73 m and assigned them to groups on the basis of eGFR of at least 60 without (group A, n=66) or with microalbuminuria or eGFR 45 to less than 60 (group B, n=220). The 3-year incidence of cardiac events and the value of MPI were evaluated., Results: Cardiac events developed in 1.52 and 4.55% of patients in groups A and B, respectively. Event-free survival did not differ according to summed stress scores in group A but was significantly lower among patients with summed stress scores of at least 9 in group B., Conclusion: Routine MPI might be useful for stratifying risk among diabetic patients with mild renal dysfunction but is unnecessary for those with good renal function.

Purpose: This study estimates whether myocardial perfusion single photon emission computed tomography (SPECT) can predict the prognostic risk of cardiac events among patients with diabetes and relatively mild chronic kidney disease (CKD)., Methods: Data from 2423 patients in the Japanese Assessment of Cardiac Events and Survival Study were examined. Patients were classified into group A (diabetes-, CKD-), B (diabetes-, CKD+), C (diabetes+, CKD-), and D (diabetes+, CKD+). After 3 years of follow-up, the incidence of cardiac events and the ability of myocardial perfusion SPECT to estimate prognosis were evaluated., Results: A total of 119 (4.9%) events (28 cardiac deaths, 25 myocardial infarctions, and 66 severe heart failures) occurred. Each type of event occurred more frequently in CKD compared with non-CKD groups with both diabetic and nondiabetic populations. Risk was higher in patients with high summed stress scores. Risk gradually increased in nondiabetic groups according to the decrease in the estimated glomerular filtration rate and roughly consisted of two diabetic groups with a cutoff of eGFR equal to 50 ml/min., Conclusion: A high incidence of cardiac events is associated with CKD in both nondiabetic and diabetic patients. Summed stress scores obtained by myocardial perfusion SPECT have a highly incremental value for predicting the cardiac prognosis of patients with diabetes and CKD. These scores are useful for the risk stratification of asymptomatic patients with relatively mild renal dysfunction requiring neither dialysis nor renal transplantation.

Objective: This study was conducted in an attempt to use blood flow scintigraphy with 99mTc-hexakis-2-methyoxy-isobutylisonitrile (99mTc-MIBI) for the evaluation of the angiogenic effect of hepatocyte growth factor (HGF) plasmid in a rat model of hind limb ischemia., Materials and Methods: The femoral artery of the left hind limb of each rat was ligated to create a model of hind limb ischemia. Three weeks later, HGF plasmid (1.5 mg/1.1 ml/body) or saline (1.1 ml/body) was administered intramuscularly into three sites of the ischemic hind limb. Two and 4 weeks after the treatment, blood flow through the hind limb was measured by 99mTc-MIBI scintigraphy. In addition, the number of capillary endothelial cells obtained by immunostaining for CD31 was counted., Results: After 99mTc-MIBI scintigraphy in the HGF plasmid-treated group, the blood flow ratio increased significantly from the pretreatment ratio 63.8 to 73.4%, 2 weeks after treatment (P<0.05) and to 97.8%, 4 weeks after treatment (P<0.05). The number of CD31-positive endothelial cells was significantly higher in the HGF plasmid-treated group than in the control group., Conclusions: The experimental study using a rat model of hind limb ischemia showed usefulness of 99mTc-MIBI scintigraphy to evaluate the angiogenic effect of HGF plasmid treatment.

Objective: To construct a region-of-interest (ROI) template for Z-score images of three-dimensional stereotactic surface projections (3-D SSP) and to assess whether the ROI template can be a useful tool for evaluation of brain perfusion abnormalities of neurological disorders., Materials and Methods: We constructed the ROI template for Z-score images of 3-D SSP based on the standardized magnetic resonance imaging data of 10 healthy volunteers. We assigned a total of 26 ROIs to Z-score images and superimposed it on Z-score images constructed from the brain perfusion SPECT data of 15 patients with Alzheimer's disease and 10 patients with mild cognitive impairment (MCI) who developed Alzheimer's disease within the following 2 years. We then obtained the mean Z-scores of each ROI and examined them to determine whether the hypoperfusion typical of Alzheimer's disease had been demonstrated quantitatively. We also visually inspected the Z-score image of each patient in both groups to determine whether the areas with the highest Z-scores were demonstrated within the ROIs of regions typical of Alzheimer's disease., Results: In the patients with Alzheimer's disease, our ROI template quantitatively demonstrated hypoperfusion in regions typical of the disease and the Z-scores were very high. In the MCI patients, the mean Z-scores of the ROI in the posterior cingulated gyrus were the highest among all regions. Visual inspection of the Z-score images of each patient in both groups confirmed that the areas with the highest Z-scores were demonstrated within the ROIs in regions typical of Alzheimer's disease in all cases., Conclusion: Use of 3-D SSP methods and our ROI template enables automated quantitative evaluation of brain function images over the entire brain surface. In addition, the ROI template may facilitate visual interpretation of functional images of individual patients with neurological disorders.

Objective: Conventional methods of quantitative Na18F positron emission tomography require multiple arterial blood sampling in order to obtain the input function, and the procedures are invasive and complicated. This study aims to establish a simplified and reliable technique for obtaining the input function., Methods: Multiple arterial blood sampling was performed on 12 persons. The time point for one-point sampling was determined as the time when (1) the plasma radioactivity obtained showed the highest correlation to the real integrated value, which was calculated from the input function, and (2) the coefficient of variation of the real integrated value divided by plasma radioactivity obtained at each time point became the minimum. Scaling factors were obtained in order to estimate the plasma radioactivity at each time point, and a reference table was produced in order to estimate the input function., Results: The optimal timing for one-point sampling was 12 min after intravenous injection of Na18F. The estimated integrated value obtained from arterial blood sampling at 12 min and the reference table was highly correlated with the real integrated value (P<0.001). Levels of plasma radioactivity of arterial blood and venous blood were almost the same at 12 and 40 min after Na18F injection. Percentage errors in the estimation of the integrated value were 2.63% (n=12) for the arterial blood collected at 12 min and 4.14% (n=12) for the venous blood collected at 30 min., Conclusions: This simplified method is clinically applicable and would replace traditional methods that require multiple blood sampling.

Objectives: Oestrogen has been shown to increase nitric oxide-mediated vasodilatation and modulate sympathetic tone in postmenopausal women. We investigated the acute effects of oestrogen on the coronary microcirculation in men., Methods: Myocardial blood flow was quantified using N-ammonia positron emission tomography before and 20 min after an intravenous administration of conjugated oestrogen (10 mg) in nine healthy men., Results: There were no significant changes in either systemic blood pressure or heart rate before and after oestrogen infusion. However, myocardial blood flow was increased by oestrogen from 0.88 +/-0.06 to 1.05+/-0.09 ml x g x min (P<0.05). Although serum levels of nitrite/nitrate (end products of nitric oxide) were not increased, circulating norepinephrine (noradrenaline) levels were decreased after the administration of oestrogen from 401+/-114 to 346+/-112 pg x ml (P<0.01). A significant negative correlation was found between myocardial blood flow and plasma norepinephrine levels (r=-0.67, P<0.05)., Conclusions: A single administration of oestrogen enhanced myocardial circulation in healthy men. The oestrogen-induced increase in myocardial blood flow may be due to direct effects on the coronary circulation or through the modulation of norepinephrine levels, rather than the production of nitric oxide.

Neuroblastomas sometimes recur after the initial disappearance of the tumour. We evaluated the utility of meta-[123I]iodobenzylguanidine (123I-MIBG) scintigraphy for the detection of recurrent neuroblastomas by comparing with the measurement of biochemical markers and clinical findings. Forty patients who had received treatment for neuroblastomas were included in the study. After the disappearance of the initial tumours, periodic measurements of urinary vanillyl mandelic acid, homovanillic acid and serum neuron specific enolase values, and an 123I-MIBG scintigraphy were performed. Whenever an abnormal finding was observed, other appropriate examinations and/or follow-up examinations were performed to elucidate the true state of the patient. Eleven recurrent episodes in eight patients were observed. Most of them occurred in the bone marrow or bone. Corresponding symptoms were observed in only two episodes; the other episodes were asymptomatic, and discovered by the periodic examinations. 123I-MIBG scintigrams visualized the recurrent tumours in 10 (91%) episodes. Elevated tumour markers were observed in only three episodes. 123I-MIBG scintigrams visualized most of the recurrent tumours, unless they were accompanied by any symptoms or elevations in biochemical tumour markers. Periodic examinations with 123I-MIBG scintigraphy appears to be a useful technique for the detection of the recurrences.

Clinical studies using 18F-fluorodeoxyglucose suggest that this tracer may overestimate myocardial viability. This study aimed to elucidate whether 2-deoxyglucose accurately indicates myocardial viability at the early phase of myocardial infarction. Autoradiography with 14C-deoxyglucose was performed in fasting rats whose left coronary artery was occluded for 60 min and then reperfused. 14C-deoxyglucose was injected 30 min after the reperfusion (acute; n=10) or 1 week later (subacute; n=9). Infarction and risk areas were identified by triphenyl tetrazolium chloride or haematoxylin-eosin staining and methylene blue, respectively. Immuno-histochemical staining using anti-glucose transporter 1 and 4 antibodies was performed. At the acute stage, the uptake of deoxyglucose was consistent with the grade of anti-glucose transporter 4 expression. At the subacute stage, the uptake of deoxyglucose in poorly viable myocardium (543.4+/-343.7%: normalized with the uptake at the right ventricle) as well as in the viable one (335.2+/-149.8%) in the risk area was significantly greater than that in the remote area (116.4+/-94.9%, P<0.01). Anti-glucose transporter 1 was expressed in the poorly viable area where inflammatory cells infiltrated. It is concluded that deoxyglucose uptake by inflammatory cells which express anti-glucose transporter 1 causes overestimation of myocardial viability at subacute stage.

Fifty-six patients with hypertrophic cardiomyopathy who had echocardiography and cardiac catheterization were studied. Eleven (18%) of 56 patients had right ventricular (RV) thallium-201 visualization at resting scan. RV thallium-201 visualization was observed in the apex or lower half of the RV free wall, which was quite different from that with RV pressure or volume overload. There was no significant correlation between RV thallium-201 visualization and interventricular septal thickness or haemodynamic data. RV systolic pressure and RV dimension were within normal limits whether RV visualization was observed or not. Thus, an abnormal increase of RV mass in hypertrophic cardiomyopathy may lead to RV thallium-201 visualization without RV pressure or volume overload.