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Purpose This study aimed to evaluate the effect of chemical exchange saturation transfer (CEST) on the ischemic regions in hypoxic-ischemic encephalopathy (HIE) in comparison with diffusion-weighted imaging (DWI) and magnetic resonance spectroscopy (MRS) using a 7T-MRI. Methods We used neonatal rats (n = 8), aged 8 days, to clarify the progression of HIE. The rat model of HIE was developed by ligating and severing the left common carotid artery, followed by 45 minutes of recovery, and 60 minutes of hypoxia (8% O2/92% N2; 34°C). At 0-2 and 24 hours after the onset of HIE, CEST imaging, DWI, and MRS were performed with a 7T-MRI. The magnetization transfer ratio (MTR) asymmetry curves and four MTR asymmetry maps at 0.5, 1.0, 2.0, and 3.5 ppm were calculated using the CEST images. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) maps were calculated by DWI, and brain metabolites were assessed by MRS. Results In the ischemic regions of neonatal rats, FA was significantly increased at 0-2 hours and decreased at 24 hours after the onset of HIE. ADC in the ipsilateral side was significantly lower than that of contralateral side. All rats with HIE showed hypointense areas on MTR asymmetry maps (2.0 and 3.5 ppm), that did not correspond with the hyperintense areas on DWI. In addition, a significant increase in lactate levels was observed at 0-2 and 24 hours after the onset of HIE. Conclusion CEST MTR maps did not correspond with the hyperintense areas on DWI at 0-2 and 24 hours after the onset of HIE. The change of multi offset CEST signal may be primarily related to the brain metabolites and pH alterations, such as that caused by lactate, after the onset of HIE.

Cell tracking with magnetic resonance imaging (MRI) is important for evaluating the biodistribution of transplanted cells. Umbilical cord-derived mesenchymal stem cells (UC-MSCs) have emerged as a promising therapeutic tool in regenerative medicine. We examined the UC-MSCs labeled with superparamagnetic (SPIO) and ultrasmall superparamagnetic iron oxide (USPIO) in terms of cell functioning and imaging efficiency in vitro and in vivo. The UC-MSCs were co-incubated with SPIO or USPIO at a concentration of 50 or 100 µg/mL of label. Viability and proliferation were assessed by Trypan blue dye exclusion and MTT assay, respectively. Differentiation (chondrogenesis, osteogenesis, and adipogenesis) was induced to examine the impact of labelling on stemness. For in vitro experiments, we used 7-T MRI to assess the T2 values of phantoms containing various concentrations of cell suspensions. For in vivo experiments, nine neonatal rats were divided into the control, SPIO, and USPIO groups. The UC-MSCs were injected directly into the rat brains. MRI images were obtained immediately and at 7 and 14 days post injection. The UC-MSCs were successfully labeled with SPIO and USPIO after 24 h of incubation. Cell viability was not changed by labelling. Nevertheless, labelling with 100 µg/mL USPIO led to a significant decrease in proliferation. The capacity for differentiation into cartilage was influenced by 100 µg/mL of SPIO. MRI showed that labeled cells exhibited clear hypointense signals, unlike unlabeled control cells. In the USPIO-labeled cells, a significant (P 2 values (= improved contrast) was observed when compared with the controls and between phantoms containing the fewest and the most cells (0.5 × 106 versus 2.0 × 106 cells/mL). In vivo, the labeled cells were discernible on T2-weighted images at days 0, 7, and 14. The presence of SPIO and USPIO particles at day 14 was confirmed by Prussian blue staining. Microscopy also suggested that the regions occupied by the particles were not as large as the corresponding hypointense areas observed on MRI. Both labels were readily taken up by the UC-MSCs and identified well on MRI. While SPIO and USPIO provide improved results in MRI studies, care must be taken while labelling cells with high concentrations of these agents.

OBJECTIVES Drugs are mainly metabolized by hepatic enzymes, the activity of which can differ between individuals. Although it is ideal to measure the hepatic clearance of liver-targeted drugs in individualized medicine, blood enzyme tests typically measure metabolic drug clearance in the entire body, and not just in the liver. We investigated whether I-iomazenil imaging can directly assess and quantify the activity of hepatic drug-metabolizing enzymes. MATERIALS AND METHODS Hepatic enzymes that metabolize I-iomazenil were identified by thin-layer chromatography in mouse liver homogenates with bis(4-nitrophenyl) phosphate (BNPP) inhibitor for carboxylesterase enzymes and nicotinamide adenine dinucleotide phosphate (NADPH) generator for cytochrome P450 enzymes. Whole-body images of mice were acquired using I-iomazenil with and without BNPP, and the distribution was also obtained. The metabolism of I-iomazenil in the blood, liver, gall bladder, and bladder was investigated by thin-layer chromatography. RESULTS From the in-vitro metabolism of I-iomazenil using BNPP, the enzyme converting I-iomazenil to I-R-COOH was identified as carboxylesterase, and that converting I-iomazenil to M2 was identified as cytochrome P450 in experiments with and without an NADPH generator. The biological distribution and whole-body imaging showed increased accumulation in the liver of mice administered BNPP compared with normal mice, but decreased levels in the gall bladder and small intestine. The main fraction in bile and urine was I-R-COOH, with two unknown metabolites (M1 and M2), I, and I-iomazenil also being present. CONCLUSION I-iomazenil whole-body imaging has good possibility of direct measurement of hepatic carboxylesterase activity as accumulation of I-R-COOH in the gall bladder through bile and in the bladder through urine.

Cadmium-zinc-telluride (CZT) detectors have recently been introduced to the field of clinical nuclear cardiology. However, the feasibility of using them for organs other than the heart remains unclear. The aim of this study was to evaluate the potential of a cardiac CZT camera to acquire thyroid and parathyroid images. We used custom-made phantoms and the currently available standard protocols for a CZT camera, instead of a sodium-iodine scintillation (NaI) camera. Methods: Thyroid phantoms with or without parathyroid adenomas were made from agar using radiopharmaceuticals (99mTc or 123I) and imaged using CZT and NaI cameras. Using the CZT camera data, we prepared maximum-intensity-projection (MIP) images and planar-equivalent images. Image counts were compared with those from the NaI camera, and the radioactivity of the phantoms was measured. For parathyroid imaging, 3 different protocols with the NaI camera were tested using MIP images. Results: For thyroid imaging, MIP could provide images as clear as those obtained from the NaI camera. The radioactivity and image counts correlated better for the planar-equivalent images than for the MIP images, especially for 123I. We succeeded in obtaining clear parathyroid adenoma images from MIP images using all 3 protocols. Conclusion: A cardiac CZT camera can effectively perform qualitative and quantitative assessments of the thyroid and parathyroid organs.

OBJECTIVE Cadmium-zinc-telluride detectors enable shorter acquisition durations in myocardial perfusion imaging (MPI), but the time interval of sequential scanning is still unchanged in clinical practice. We designed a very rapid 1-day protocol of MPI using cadmium-zinc-telluride single-photon emission tomography and evaluated the optimal dose ratio between two scanning acquisitions by means of simulations and phantom experiments. METHODS We intended to perform a 1-day MPI within 140 min and simulate radioactivities in the second scan under various injected dose ratios. To apply this, a cardiac phantom was scanned with various radioactivities and scans were compared with a reference scan with the ideal tracer concentrations. RESULTS In the stress-first protocol, the dose ratio 1 : 5 was enough to show the same regional percentage uptake compared with the reference. However, in the rest-first protocol, the regional percentage uptakes were higher than those of the reference image even with a 1 : 6 dose ratio. CONCLUSION The injected dose ratio 1 : 5 is optimal in a stress-first rapid 1-day protocol. The rest-first protocol is not appropriate because a dose ratio greater than 1 : 6 is required to withdraw shine-through artifacts.

Ionizing radiation generated during medical imaging procedures is a matter of concern. However, the current status of radiopharmaceutical use in stress myocardial perfusion imaging (MPI) and the radiation exposure from these radiopharmaceuticals is unknown in Japan. A nationwide survey was conducted from June through July 2016. The questionnaires on the radiopharmaceuticals used and their administered doses during stress MPI were sent to 641 nuclear medicine facilities. The responses were collected from 431 facilities and the effective dose (ED) for an adult with standard body weight was calculated. Forty-three percent of the facilities used only 201TlCl, 35% used only 99mTc radiopharmaceuticals, and the remaining 22% used both. The two main reasons for using 201TlCl instead of 99mTc radiopharmaceuticals were “more familiarity with the usage of 201TlCl than 99mTc radiopharmaceuticals” and “apprehension about increasing the burden of physicians performing tracer injection twice.” The mean ED was 14.0 ± 5.5 mSv (range, 3.9 to 25.2 mSv), which was higher than that reported in other countries. The ED of stress MPI radiopharmaceuticals in Japan is probably higher than the world standard because more than 50% of the facilities still use 201TlCl. We recommend revising the routine stress MPI protocol to reduce the effects of ionizing radiation.

Purpose To evaluate the utility of neurite orientation dispersion and density imaging (NODDI) for longitudinally assessing neonatal hypoxic-ischemic (HI) encephalopathy severity with 7.0 T magnetic resonance imaging. Methods Thirteen 8-day-old Wistar rats underwent unilateral ligation of the left common carotid artery followed by mild (1 h; n = 6) or severe (2 h; n = 7) hypoxic exposure (8% O2, 34 °C). Diffusion-weighted, T2-weighted (T2W), and flow-sensitive alternating inversion recovery images were obtained with a horizontal 7.0 T scanner at 1, 24, 72, and 168 h after HI insult. The fractional anisotropy (FA), apparent diffusion coefficient (ADC), intracellular volume fraction (ICVF), isotropic volume fraction (ISO), orientation dispersion index (ODI), and cerebral blood flow (CBF) values were calculated for each group (mild and severe) at each time point (1, 24, 72, and 168 h). ICVF, ISO, and ODI were the NODDI parameters. Results Left hemisphere brain damage was identified as slight hyperintensity on T2W images after 1 h in both groups. In the severe group only, the signal hyperintensity increased time-dependently over 168 h. The ADC and CBF were not significantly different between the groups within any region. The ICVF and ODI were significantly higher in the severe vs. mild group at various points between 1 and 168 h (cortex, striatum, or white matter), whereas the FA was significantly higher in the mild vs. severe group at 168 h (cortex and white matter). The ISO was higher in the severe vs. mild group at 72 h (striatum) and 168 h (all regions), while the ISO was significantly higher in the mild vs. severe group at 24 h (all regions). Conclusion Here, ODI, a NODDI metric, identified early differences between mild and severe HI injuries. Our findings support the potential utility of NODDI for determining neonatal HI encephalopathy severity in rats.

Little is known about the affinity and stability of 99mTc-labeled 2-methoxyisobutylisonitrile (99mTc-MIBI) and tetrofosmin (99mTc-TF) for imaging of multiple drug resistance transporters in cancer. We examined the affinity of 99mTc-labeled compounds for these transporters and their stability. 99mTc-MIBI and 99mTc-TF were incubated in vesicles expressing P-glycoprotein (MDR1), multidrug resistance-associated protein (MRP)1–4, or breast cancer resistance protein with and without verapamil (MDR1 inhibitor) or MK-571 (MRP inhibitor). Time activity curves of 99mTc-labeled compounds were established using SK-N-SH neuroblastoma, SK-MEL-28 melanoma, and PC-3 prostate adenocarcinoma cell lines, and transporter expression of multiple drug resistance was measured in these cells. The stability was evaluated. In vesicles, 99mTc-labeled compounds had affinity for MDR1 and MRP1. 99mTc-TF had additional affinity for MRP2 and MRP3. In SK-N-SH cells expressing MDR1 and MRP1, MK-571 produced the highest uptake of both 99mTc-labeled compounds. 99mTc-MIBI uptake with inhibitors was higher than 99mTc-TF uptake with inhibitors. 99mTc-TF was taken up more in SK-MEL-28 cells expressing MRP1 and MRP2 than PC-3 cells expressing MRP1 and MRP3. 99mTc-MIBI was metabolized, whereas 99mTc-TF had high stability. 99mTc-MIBI is exported via MDR1 and MRP1 (MRP1 > MDR1) at greater levels and more quickly compared to 99mTc-TF, which is exported via MDR1 and MRP1–3 (MRP1 > MDR1; MRP1, 2 > MRP3). Because 99mTc-MIBI is metabolized, clinical imaging for monitoring MDR and shorter examination times may be possible with an earlier scanning time on late phase imaging. 99mTc-TF has high stability and accurately reflects the function of MDR1 and MRP1–3.

Little is known about the affinity and stability ofIn vesicles

Objectives: Little is known about the affinity of 99mTc-labeled 2-methoxyisobutylisonitrile (99mTc-MIBI) and tetrofosmin (99mTc-TF) for multiple drug resistance in cancer cells. Additionally, if 99mTc-labeled compounds are metabolized immediately after injection, imaging with these compounds may not allow monitoring of multiple drug resistance in cancer cells. We examined the affinity of 99mTc-labeled compounds for these transporters and their stability in vivo. Methods: 99mTc-MIBI or 99mTc-TF was incubated in vesicles expressing P-glycoprotein (MDR1), multidrug resistance-associated protein (MRP)1-4, or breast cancer resistance protein with and without verapamil (MDR1 inhibitor) or MK-571 (MRP inhibitor). Time activity curves of 99mTc-labeled compounds were established using SK-N-SH neuroblastoma, SK-MEL-28 melanoma, and PC-3 prostate adenocarcinoma cell lines, and transporter expression of multiple drug resistance was measured in these cells. The stability of 99mTc-labeled compounds was evaluated in mice and human liver S9 fractions. Results: In vesicles, 99mTc-labeled compounds had affinity for MDR1 and MRP1. 99mTc-TF had additional affinity for MRP2 and MRP3. In SK-N-SH cells expressing MDR1 and MRP1, MK-571 produced the highest uptake of both 99mTc-labeled compounds. 99mTc-MIBI uptake with inhibitors was higher than 99mTc-TF uptake with inhibitors. 99mTc-TF was taken up more in SK-MEL-28 cells expressing MRP1 and MRP2 than PC-3 cells expressing MRP1 and MRP3. 99mTc-MIBI was metabolized after a 30-min incubation in SK-N-SH cells, mouse liver, human liver S9 fractions, and plasma. 99mTc-TF had high stability. Conclusion: 99mTc-MIBI is exported via MDR1 and MRP1 (MRP1 > MDR1) at greater levels and more quickly compared to 99mTc-TF, which is exported via MDR1 and MRP1-3 (MRP1 > MDR1; MRP1, 2 > MRP3). Although 99mTc-MIBI is metabolized, clinical imaging for monitoring MDR and shorter examination times may be possible with an earlier scanning time on late phase imaging. 99mTc-TF has high stability and accurately reflects the function of MDR1 and MRP1-3.

Regulation of metabolic activity in adipose tissue is of great concern for treating obesity. This study aimed to evaluate the adrenergic regulation of glucose uptake and the thermogenic program in adipose tissues in mouse models of both type 1 and 2 diabetes mellitus (DM). Male mice were treated with streptozotocin to induce type 1 (T1) DM, and obese ob/ob mice were used for the type 2 (T2) DM model. After selective β3-adrenoreceptor stimulation by CL 316,243 (CL) treatment, 2-deoxy-d-[14C]glucose ([14C]DG) was administered to DM and corresponding control mice. Radioactivity and uncoupling protein 1 (UCP1) expression were measured and analyzed in adipose tissues. In T1DM, [14C]DG uptake in brown adipose tissue (BAT) decreased both at rest and upon CL stimulation, and UCP1 expression was preserved. However, CL treatment enhanced [14C]DG uptake without impairing UCP1 expression in inguinal white adipose tissue (iWAT). In this model, CL could not alter blood glucose levels. In T2DM mice, the blood glucose level was significantly lowered by CL treatment. There was no decrease in CL-induced [14C]DG uptake in BAT, and UCP1 expression was maintained. However, [14C]DG uptake was not increased in iWAT and no UCP1 expression was observed in iWAT (browning). The metabolic response against adrenergic stimulation varied depending on the type of adipose tissue and DM. This could be important for the therapeutic activation of adipose tissue metabolism in obese diabetic patients.

Introduction Although [S-methyl-11C]-labeled L-methionine and D-methionine ( 11 C-L-MET and 11 C-D-MET) are useful radiotracers for positron emission tomography imaging of brain tumors, it is not known whether the accumulation and transport mechanisms underlying uptake of 11 C-D-MET and 11 C-L-MET are the same. 11 C-L-MET is mainly taken up by the amino acid transport system L. We evaluated accumulation and the transport mechanism of D-MET in high- and low-grade human glioma cells in vitro. Methods The expression of transport system genes in high- (A172 and T98G) and low-grade (SW1088 and Hs683) glioma cells was quantitatively analyzed. Accumulation of [S-methyl- 3 H]-L-MET ( 3 H-L-MET) and [S-methyl- 3 H]-D-MET ( 3 H-D-MET) in these cells was compared during 60min of incubation. The transport mechanism of 3 H-L-MET and 3 H-D-MET was investigated by incubating the cells with these compounds and examining the effect of the inhibitors 2-amino-2-norbornane-carboxylic acid or α-(methylamino) isobutyric acid. Results Absolute expression levels of system L and system alanine–serine–cysteine (ASC) in high-grade glioma cells were higher than in low-grade cells. In high-grade glioma cells, expression of system ASC genes was higher than that of system L genes. 3 H-D-MET, which is transported by systems L and ASC, accumulated at higher levels than 3 H-L-MET at all incubation times because 3 H-D-MET is more sensitive to system ASC than 3 H-L-MET. Conversely, in low-grade glioma cells with lower expression of system L and ASC, 3 H-D-MET accumulated at higher levels than 3 H-L-MET in early incubation times because 3 H-D-MET may be more sensitive to system ASC than system L. Conclusion 3 H-D-MET was mainly transported by systems L and ASC and sensitive to system ASC, whereas 3 H-L-MET was transported by system L in human glioma cells. In vitro, the accumulation of 3 H-D-MET was significantly higher than that of 3 H-L-MET during the entire incubation time in high-grade glioma cells, and in early incubation times in low-grade glioma cells.

A 70-year-old woman with a submucosal gastric tumor was referred to our hospital for surgical treatment. Upon examination, it was found that she had hypertension, and abdominal computed tomography revealed swelling on both adrenal glands. The patient was examined with gamma camera imaging and iodine-123 metaiodobenzylguanidine (MIBG), because her hypertension was thought to be due to a suspected adrenomedullary tumor. The planar image showed an unexpected abnormal uptake of MIBG in the upper abdomen. On single-photon emission computed tomographic images, the area of abnormal tracer uptake was thought to correspond to the known gastric tumor. The surgical procedure and histological assessments revealed that the gastric tumor was a gastrointestinal stromal tumor (GIST). MIBG can accumulate in GISTs as well as in neuroendocrine tumors of the medulla of the adrenal glands. Although the cause of radiolabeled MIBG uptake in GISTs is uncertain, further studies are necessary to establish the significance of MIBG scintigraphy in GIST imaging.

We report a rare case of benign esophageal schwannoma showing [18F]-fluorodeoxyglucose (FDG) uptake on positron emission tomography computed tomography (PET-CT). A 43-year-old woman diagnosed with left breast cancer was referred to our hospital for further treatment. Preoperative PET-CT showed a significant accumulation [maximum standardized uptake value (SUVmax) 2.5] in the upper thoracic esophagus. Endoscopy revealed a submucosal tumor about 40 mm in size in the upper thoracic esophagus. Endoscopic ultrasonography-guided fine-needle aspiration biopsy did not reveal the histological diagnosis. The patient underwent thoracoscopic enucleation of the tumor. The resected tumor measured 40 × 20 mm. Microscopically, the tumor consisted of spindle cells. Immunohistochemistry was positive for S-100 and vimentin and was negative for KIT (CD117) and CD34. The final diagnosis was benign esophageal schwannoma.

Primary aldosteronism (PA) may account for as much as 6-20% of cases of refractory hypertension referred to hypertension clinics. Because antihypertensive agents affect the physiologic renin-angiotensin-aldosterone system, screening diagnostic tests for PA are generally performed after antihypertensive agents are discontinued. However, such tests can be dangerous for patients with severe hypertension or other cardiovascular complications. However, a reliable cutoff value for the aldosterone-to-renin ratio (ARR) has not been established, especially for Asians, including the Japanese.Fifty-five consecutive patients with clinically suspected PA were evaluated from July 10, 2001, to March 1, 2005, at the National Cardiovascular Center in Japan. Every referred patient was screened prospectively for PA with the ARR at the outpatient clinic. The patients tested continued to be treated with a variety of antihypertensive agents. We reviewed the sensitivity, specificity, and accuracy of the ARR without modifying the antihypertensive agents. The diagnosis of PA was established with the results of both abdominal computed tomography and adrenal scintigraphy.Of the 55 patients, 27 were found to have PA, including adrenal adenoma (n = 18) and bilateral adrenal hyperplasia (n = 9). The mean ARR of patients with PA was significantly higher than that of patients without PA. By assuming a cutoff value of the ARRor= 69 calculated from the receiver operating characteristics curve, the highest sensitivity (81%), specificity (82%), positive-predictive value (81%), and negative-predictive value (81%) were obtained.The data suggest that an ARRor= 69 strongly indicates PA in Japanese patients with hypertension being treated with antihypertensive agents.

Patients with isolated congenital complete atrioventricular block (CCAVB) occasionally develop dilated cardiomyopathy (DCM), despite early pacemaker implantation. However, the etiology of the DCM and its relationship to permanent ventricular pacing are not fully understood. Twenty-five patients with CCAVB underwent (99m) technetium (Tc) myocardial perfusion scintigraphy. Five patients were studied before and after pacing, providing a total of 30 image sets, which were divided into three groups; group 1: CCAVB before pacemaker implantation (PMI) (n = 11); group 2: CCAVB after PMI who did not subsequently develop DCM (n = 13); group 3: CCAVB after PMI who subsequently developed DCM (n = 6). Perfusion defects on single-photon-emission computed tomography (SPECT) were identified in group 1, 0 of 11 patients; group 2, 85% of patients; and group 3, 100% of patients. In groups 2 and 3, in patients with right ventricular pacing, the perfusion defects were mainly in the septum or between the apex and septum. On 20 segments' polar maps, the distribution of %uptake showed a similar pattern in groups 2 and 3, the degree of decreased %uptake and the number of segments with decreased %uptake being more severe in group 3. "Artificial" left bundle branch block (LBBB) pattern myocardial contraction induced by right ventricular pacing decreased myocardial perfusion around the apex and septum. Some patients with CCAVB will develop left ventricular dysfunction caused by artificial LBBB-induced interventricular asynchrony.

Aims: Renal dysfunction occurs occasionally after the repair of abdominal aortic aneurysm (AAA), and preoperative renal function is considered as one of the potential causes. The present study was designed to evaluate and compare renal function and risk factors of AAA patients with those of hypertensive patients. Methods: We prospectively examined 95 patients with AAA and 72 patients with essential hypertension (HT) without other cardiovascular diseases (CVD). Renal function, urinary albumin excretion (UAE) and renal scintigraphy were compared. Kidney size was calculated using ultrasonography. Results: Serum creatinine and creatinine clearance in AAA patients was worse than in HT patients. Smoking status was more apparent in AAA patients. Renal artery stenosis occurred in 8 patients with AAA. Renal scintigraphy showed normal function in 19%, hypofunction in 69% and severe dysfunction in 12% of the AAA patients, and normal function in 42% and hypofunction in 58% of the HT patients (p < 0.0001). Multivariate linear regression analysis showed that renal function was related to age, UAE, CVD, smoking status and kidney size for all patients, UAE, CVD, smoking status and kidney size for AAA patients, and age and kidney size for HT patients. Conclusion: Renal function of AAA patients was worse than HT patients without other CVD. The risk factors for renal dysfunction were different between AAA and HT patients. These preoperative conditions may relate to the postoperative renal dysfunction seen in AAA patients.

Objective Radionuclide imaging with fluorodeoxyglucose (FDG) and positron emission tomography (PET) has been proposed for the identification of vascular graft infection; however, its accuracy has not been determined. We performed this prospective study to compare the usefulness of FDG-PET in the assessment of vascular graft infection relative to computed tomography (CT). Methods FDG-PET was performed for 33 consecutive patients with a suspected arterial prosthetic graft infection. The PET images were then assessed visually in terms of the density of uptake. In cases with positive uptake, the pattern of accumulation was also defined, such as focal or diffuse uptake. We compared the diagnostic efficiency of PET with contemporaneous CT in detection of infection of the arterial prosthetic graft. Results On the basis of the surgical, microbiological, and clinical follow-up findings, the aortic grafts were considered infected in 11 patients and not infected in 22 patients. Although the sensitivity of PET (91%) was higher than that of CT (64%), its specificity (64%) was lower than that of CT (86%). When focal uptake was set as the positive criterion in FDG, the specificity and positive predictive value of PET for the diagnosis of aortic graft infection improved significantly to 95% ( P Conclusions Although both techniques are useful in evaluation of patients with suspected aortic graft infection, using the characteristic FDG uptake pattern described previously as a diagnostic criterion made the efficacy of FDG superior to that of CT in the diagnostic assessment of patients with suspected aortic graft infection.

Background Recently, it has been proposed that discontinuation of antihypertensive medications is not necessarily essential for the measurement of plasma aldosterone-to-renin ratios. We examined the efficacy of adrenocortical scintigraphy performed without modification of antihypertensive medications. Methods A retrospective study was conducted on 119 patients, in whom functional tests, anatomic studies, and adrenocortical scintigraphy were replete. Interrelationship among these was studied. The patients tested were being treated with antihypertensive medications from several classes including angiotensin-converting enzyme inhibitors, calcium antagonists, β-blockers, diuretics, and spironolactone. Results Significantly higher percentage of scintigraphy positive patients had plasma aldosterone-to-renin ratio of greater than 25:1. Positive rate for adrenal nodules by anatomic studies was significantly higher in the scintigraphy positive patients than in the scintigraphy negative patients. Finally, the percentage of patients who underwent adrenalectomy was higher in the scintigraphy positive patients than in the scintigraphy negative patients. Conclusions We conclude that adrenocortical scintigraphy is a valid evaluation tool for primary aldosteronism and that the discontinuation of antihypertensive medications is not a requirement for this test.

The present study examines whether or not baseline and acetazolamide (ACZ) Tc-99m MAG3 renography can assess renal blood flow reserve.Renography proceeded for 50 min after sequential injections of 370 MBq Tc-99m MAG3 for baseline renography and 10 min after a 1,000 mg injection of ACZ for ACZ renography. Effective renal plasma flow of renal cortex (cERPF) in each kidney and the percentage change in cERPF of those parameters (deltaERPF) were obtained before and after the administration of ACZ in 10 subjects without hypertension or diabetes (normal group), in 10 with essential hypertension (hypertensive group) and in 10 who had Type 2 diabetes with hypertension (diabetic group). A placebo test was performed in the 10 without hypertension or diabetes using distilled water instead of ACZ (placebo group).The placebo test performed in the 10 without hypertension or diabetes using distilled water instead of ACZ indicated that the parameter variance between the two types of renogram was below 3.2%. The cERPF of baseline and ACZ Tc-99m MAG3 renography and deltaERPF in the normal, hypertensive and diabetic groups were 89 +/- 10 and 110 +/- 10 ml/min, 89 +/- 14 and 117 +/- 22 ml/min, 100 +/- 23 and 112 +/- 23 ml/min, respectively, and 24.5 +/- 13.5%, 26.0 +/- 9.7% and 12.3 +/- 11.1%, respectively. The difference in the cERPF value was significant in the normal and hypertensive groups whereas this did not change in the diabetic group before or after ACZ administration.We suggested that the deltaERPF determined by baseline and ACZ Tc-99m MAG3 renography is a useful parameter for assessing renal blood flow reserve.

Background — We explored the feasibility of measuring regional tracer activity concentrations and flow defects in myocardium of rats with a high spatial resolution small-animal PET system (microPET). Methods and Results — Myocardial images were obtained after intravenous 18 F-fluorodeoxyglucose ( 18 FDG) in 11 normal rats (group 1) and assembled into polar maps. Regional 18 F activity concentrations were measured in 9 regions of interest and compared with tissue activity concentrations measured by well counting. In another 9 rats (group 2), myocardial perfusion images were acquired with 13 N -ammonia at baseline and during coronary occlusion. On the polar maps recorded during coronary occlusion, the size of perfusion defects was measured as the myocardium with 18 FDG and 13 N -ammonia microPET images was good to excellent; the images were easily assembled into polar maps. In group 1, regional 18 F concentrations by microPET and postmortem were correlated linearly ( r =0.99; P r =0.97; P P r =0.93). Conclusions — The findings indicate the feasibility of noninvasive studies of the myocardium in rats with a dedicated small-animal PET-imaging device.

Clinical studies using 18 F-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 14 C-deoxyglucose was performed in fasting rats whose left coronary artery was occluded for 60 min and then reperfused. 14 C-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.

However, extracranial and intracranial arterial bypass surgery (EC/IC BYPASS) was denied by the randomized study, some patients may be suitable for surgery after selecting areas of misery perfusion. Steady-state O-15 positron emission tomography (PET) showed cerebral blood flow of 31.6±4.1 (ml/100 g/min) with acetazolamide reactivity of 30.6±5.4 (%) in misery perfused areas. The authors examined whether or not patients could be selected for surgery through combining cerebral blood flow (CBF) measurements with vasoreactivity determined by I-123 IMP (IMP; N-isopropyl-p-[I-123]-iodoamphetamine) single-photon emission-computed tomography (SPECT), which has good linearization at high flow ranges. Cerebral blood flow was quantified immediately after PET in 24 patients by counting I-123 IMP in arterial blood 10 min after injection. The CBF in the middle-cerebral arterial territories (MCA) was obtained by selecting regions of interest and comparing the fit between O-15 H2O and I-123 IMP using a nonlinear PS model curve. In 48 MCA areas, the CBF correlation between brain PET and IMP brain SPECT was close according to the equation, PET=12.4+0.46×IMP; r=0.743 (p

Information about myocardial perfusion and function has limitations in the assessment of disease severity and prognosis in patients with heart failure. Information about myocardial biochemistry may actually be more important in patient management. In vivo assessment of myocardial biochemistry, which started from the use of positron emission tomography, is now becoming a reality with the use of single-photon emission tomography (SPET). 123 I-BMIPP as a fatty acid tracer and 123 I-MIBG as a norepinephrine (NE) tracer are already used for clinical assessment here in Japan. In this chapter, based on our experiences, we introduce the utilities of these two tracers in assessing disease severity, the effects of medical treatment and prognosis in patients with heart failure. In 123 I-BMIPP imaging, we could not characterize metabolic abnormalities specific for idiopathic dilated cardiomyopathy, but we identified utility in differentiating ischemic from idiopathic dilated cardiomyopathy based on a high prevalence of regional myocardial 123 I-BMIPP defects in ischemic cardiomyopathy. In 123 I-MIBG imaging, we recognized the utility of the washout rate (WR) of 123 I-MIBG from the heart as an index of sympathetic activation. It showed good correlations with the plasma NE concentration and the left ventricular ejection fraction. In addition, we recognized important utilities of WR in evaluating the effectiveness of β-blocker treatment and prognosis in patients with idiopathic dilated cardiomyopathy.

Object: Hybrid single-photon emission computed tomography/computed tomography, which is recently developed, is useful for the sentinel node (SN) mapping in patients with breast cancer. However, this expensive new technology is only available at limited hospitals. The purpose of this study was to assess the feasibility of software-based computed tomography (CT) and single-photon emission tomography (SPECT) image fusion using external fiducial markers for visualization of SNs in breast cancer.Methods: Preoperative lymphoscintigraphy using 99mTc-phytate colloid was performed in 70 consecutive patients (mean age, 55.3 ± 11.8). Continually, SPECT and low-dose chest CT were performed using an 241Am-containing button as an external fiducial marker attached to the skin surface of the patient’s chest wall. The acquired SPECT and CT images were rescaled, interpolated, reformatted, and registered point-by-point on a workstation.Results: SPECT detected SN sites, including axillar (n = 96) and internal mammary lesions (n = 7). On fused images, precise overlap of hot spots shown at the corresponding lymph nodes on CT images was achieved in all but 2 cases. In cases with axillar lesions, rendering the fused images into 3D volumes with accentuation of the pectoralis minor muscle was helpful for diagnosis of SN locations in level II (n = 10). After surgery, all nodes were depicted as “hot nodes” on fused images, and 14 metastatic nodes were confirmed by histological examination.Conclusions: External fiducial-based coregistration of SPECT lymphoscintigraphic and CT images depicted the precise location of SN drainage and may provide useful information for preoperative planning, without the need for hybrid SPECT/CT.

Clinical investigations have suggested that the defects in SPECT images of a free fatty acid analog, I-123 beta-methyliodophenyl pentadecanoic acid (BMIPP) may indicate the ischemic risk area. To elucidate whether I-123 BMIPP can indicate the area at risk of ischemia, ex-vivo autoradiography was performed in rats whose left coronary artery was occluded for 60 min and then reperfused. I-123 BMIPP was injected at the acute stage (n = 10), or the subacute stage (7 days after reperfusion; n = 9). Infarction and the area at risk were identified by triphenyl tetrazolium chloride staining and injection of methylene blue during religation just before sacrifice, respectively. The BMIPP uptake in the risk area was significantly lower than that in the remote area at the acute (risk, 53.7+/-23.3% of the uptake at right ventricle, mean +/- SD; remote, 109.3+/-11.8%; p0.01) and subacute (risk, 52.5+/-11.5%; remote, 97.9+/-14.3%; p0.01) stages. In addition, the area with reduced uptake of I-123 BMIPP showed a significant correlation with the area at risk both at the acute (r = 0.98, p0.01) and subacute (r = 0.92, p0.01) stages. In conclusion, the area at risk can be evaluated by I-123 BMIPP both at the acute and subacute stages.

To elucidate the change in perfusion and aerobic metabolism in myocarditis, tissue counting and dual tracer ex vivo autoradiography with Tl-201 and a free fatty acid analog, I-123- or I-125-labeled (p-iodophenyl)-methyl-pentadecanoic acid (BMIPP), were performed in rats with myocarditis induced by immunization with cardiac myosin. Inflammatory damage was classified histologically. At the acute stage (2-4 weeks after the antigen-injection), total heart uptakes of Tl and BMIPP and the ratio (BMIPP/Tl) were significantly reduced in myocarditis rats (N = 15) compared with the controls (N = 12). Myocardial distribution of Tl and BMIPP was not homogeneous. Relative uptake of Tl and BMIPP (N = 9, 128 regions) was gradually decreased with the extent of inflammation, and the regional BMIPP/Tl was smaller than the control. At the subacute stage (7 weeks after the antigen-injection), total Tl uptake in myocarditis rats (N = 5) recovered to the control level (N = 4), but that of BMIPP was still significantly lower than the control. BMIPP/Tl was still significantly lower in myocarditis. Myocardial distribution of Tl and BMIPP recovered to be more homogeneous. Relative uptake of Tl and BMIPP (N = 6, 78 regions) still gradually but significantly decreased with the extent of inflammation. Regional BMIPP/Tl was still depressed in myocarditis. These results indicate that myocardial perfusion and aerobic metabolism were discrepant and heterogeneously suppressed with severe inflammation during the acute stages, but the difference decreases with time. Examination with Tl-201 and BMIPP may provide information about the severity of myocarditis.

Serial improvement in myocardial perfusion images from the acute or subacute to the chronic stage of acute myocardial infarction (AMI) has been attributed to improved coronary microcirculation or cell function after acute ischaemia and reperfusion. However, conventionally used non-gated imaging cannot eliminate the effect of improved regional contraction. We studied the possibility that such scintigraphic improvement reflects the functional recovery by using ECG-gated myocardial perfusion imaging with technetium-99m sestamibi. Nineteen AMI patients who received acute reperfusion therapy underwent ECG-gated myocardial single-photon emission tomography (SPET) in the subacute and chronic stages. Serial changes in regional image count distributions were analysed on the non-gated, end-diastolic (ED) and end-systolic (ES) images by using segmental mean percent peak activity (MPA) and ΔMPA (MPA in chronic stage – MPA in subacute stage) on bull’s-eye polar maps. These changes were compared with those in regional wall motion on biplane left ventriculography (LVG) from the acute (just after reperfusion) to the chronic stage. During the follow-up, regional wall motion remained the same in 42 (group A) but improved in 17 (group B) of the 59 ischaemically compromised segments. MPA showed no improvement in group A but significant improvement in group B on the non-gated and ES images (P

To evaluate the ability to detect coronary artery disease (CAD) with a new iodine-123 labeled branched fatty acid analog, iodophenyl-9-methyl pentadecanoic acid (9MPA), we performed 9MPA, iodine-123 BMIPP and thallium-201 SPECT in patients with CAD. Twenty-four patients (11 with effort angina and 13 with myocardial infarction) were studied. In all patients, 9MPA SPECT was obtained at 15 min after injection. Twenty-three patients underwent stress-redistribution 201Tl SPECT and 9 patients also underwent BMIPP myocardial fatty acid imaging. The regional uptakes of 9MPA, BMIPP and 201Tl were scored semiquantitatively and the segmental agreements were compared among them. In the segment-to-segment comparison, 9MPA showed reduced activity in comparison to stress-redistribution 201Tl imaging. The defect score of 9MPA was significantly greater than that of redistribution 201Tl images (p0.001). In addition, segmental 9MPA uptake was lower than BMIPP and its defect score was significantly greater than that of BMIPP (p0.05). When coronary angiography was used as the criterion, 9MPA showed higher sensitivity and lower specificity than stress-redistribution 201Tl (p0.01). In conclusion, fatty acid metabolic imaging with 9MPA is a sensitive but nonspecific detector of CAD.

First, we studied the diagnostic utility of myocardial imaging with 123I-BMIPP (BMIPP), a 3-methyl-branched fatty acid analog, in patients with various types of cardiomyopathy and left ventricular dysfunction (ejection fraction below 40%) by comparing with myocardial flow tracer imaging. The incidence of a dissociation between myocardial BMIPP and 201Tl distributions (BMIPP < 201Tl) as a marker of metabolic abnormality in viable tissue varied considerably among various heart diseases. Patients with ischemic cardiomyopathy and the dilated form of hypertrophic cardiomyopathy had a higher incidence while those with idiopathic dilated, alcoholic and hypertensive cardiomyopathy had a lower incidence. These results suggest that the marked difference between ischemic and idiopathic dilated cardiomyopathies may contribute to the differential diagnosis between these two diseases which are main basic abnormalities in congestive heart failure. Second, we investigated the relationship between myocardial BMIPP uptake and ventricular stress in patients with right ventricular pressure overload due to pulmonary hypertension. Myocardial BMIPP uptake in the right ventricle estimated by referring to uptake in the left ventricle showed a significant correlation with mean pulmonary artery pressure (mPAP) and no significant difference with myocardial 99mTc-sestamibi uptake in the 15-81 mmHg mPAP range. These results suggest that myocardial utilization of free fatty acid may be preserved in the presence of higher ventricular wall stress.

We have evaluated a polar cortical flow Baumkuchen map (BK map), constructed from projection data by inwardly layering cortical flow stripes from the base to the apex, to detect postural cerebral hypoperfusion using 99Tcm-HMPAO brain SPET. A circular cortical perfusion outline was constructed from sinogram data at a 20% threshold; a ring was then formed by constructing an inner line with a radius equal to half that of the outer line. This ring on the transaxial image was superimposed onto the cortical image, then divided into 60 portions at 6 degrees intervals from the centre. The maximal number of counts per pixel within each sector was determined, translated into polar coordinate profiles and displayed as a polar map. We studied 11 patients with unilateral stenosis of the internal carotid artery or middle cerebral artery (MCA) and 7 patients without stenosis, using upright and supine (rest) 99Tcm-HMPAO brain SPET Cerebral perfusion was visibly altered on the BK maps of all 11 patients with arterial stenosis and on the transaxial images of 8 of them. A semi-quantitative analysis of the BK maps using a ratio of the counts in the regions of interest over the right and left MCA areas, showed that the mean of the ratios was significantly lower in the upright images than in the upright + rest and rest images (P = 0.0044 and 0.0033, respectively). Although the difference in the means of the ratios between the upright and upright + rest images was significant for both the BK map and transaxial image data (P = 0.0044 and 0.0051, respectively), the BK map was accurate in detecting changes in perfusion in the upright position. We conclude that BK map analysis is useful for detecting changes in patients examined using upright brain SPET.

Comparative studies of thallium-201 (201Tl) and 99Tcm-tetrofosmin for the detection of ischaemic heart disease (IHD) have previously been reported. These 201Tl and 99Tcm-tetrofosmin studies were usually performed separately with different exercise loads at an interval of several days. Here, we used a dual-isotope technique with exercise myocardial SPET (single photon emission tomography) in 17 patients with IHD and 10 patients with normal coronary arteries. The triple-energy window (TEW) method was applied for cross-talk correction. SPET imaging was performed at 10 and 70 min (S1 and S2) after the injection of 99Tcm-tetrofosmin (222 MBq) and 201Tl (74 MBq) at peak exercise to determine the optimal imaging time of 99Tcm-tetrofosmin. The S2 value was obtained 35 min after the subject drank a glass of milk to accelerate hepatobiliary clearance. Twenty-five minutes after S2, 37 MBq of 201Tl were reinjected at rest and SPET imaging (S3) was performed. Immediately after S3, 666 MBq of 99Tcm-tetrofosmin were reinjected and SPET imaging (S4) was performed 50 min later. Representative short and vertical long axis tomograms were divided into 17 segments. Each segment was assessed using a 4-point scoring system. The defect score was defined as the sum of each segmental score. The defect scores for imaging at exercise were 14.3 +/- 11.4 for 201Tl at S1, 11.4 +/- 8 for 99Tcm-tetrofosmin at S1 and 9.7 +/-9.8 for 99Tcm-tetrofosmin at S2 (P < 0.01), respectively. The washout rate of 99Tcm-tetrofosmin for the first hour was 15.5 +/- 7.3% and 11.8 +/- 7.7% (P < 0.01), respectively, for the normal and ischaemic segments. The image quality of 201Tl at S1 was almost equivalent to that of 99Tcm-tetrofosmin at S1/S2. The overall sensitivity and specificity for the detection of ischaemia was 94% and 82% for 201Tl at S1, 89% and 86% for 99Tcm-tetrofosmin at S1, and 88% and 95% for 99Tcm-tetrofosmin at S2, respectively. The overall accuracy was 86%, 88% and 92%, respectively. The myocardial viability score was 7.4 +/- 7.1 for 201Tl at S3 and 5.8 +/- 7.0 for 99Tcm-tetrofosmin at S4 (P < 0.01). The results indicate that the diagnostic accuracy of 99Tcm-tetrofosmin for myocardial ischaemia is almost equivalent to that of 201Tl as assessed by dual SPET imaging, and that the optimal imaging time for 99Tcm-tetrofosmin is within 10-35 min (S1) after exercise.

A cardiac tumor was the first manifestation of acquired immunodeficiency syndrome (AIDS) in a female patient in a state of severe immunodeficiency caused by human immunodeficiency virus (HIV) infection. The extensive cardiac and extracardiac involvement shown by various imaging modalities, including echocardiography and 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), suggested that she was in the critical stage of non-Hodgkin's lymphoma (NHL). AIDS was treated by highly active-antiretroviral therapy and the NHL was treated by a combination of rituximab-cyclophosphamide-vincristine-doxorubicine-predonisolone. After 6 cycles of chemotherapy, she was in complete remission. Her cardiac tumor dramatically reduced in size and FDG-PET showed no positive uptake on whole body imaging. Generally, an AIDS-related cardiac tumor tends to be diagnosed at the late stage of the disease because of its nonspecific clinical findings, resulting in an extremely poor prognosis. In the present case, the cardiac tumor was detected by echocardiography and treated with appropriate chemotherapy. Early diagnosis and prompt treatment may improve a patient's prognosis.

We describe a patient with extra-adrenal pheochromocytoma and high plasma norepinephrine levels. Radionuclide images of this patient obtained using (18)F-fluorodeoxyglucose and (123)I-metaiodobenzylguanidine revealed bilateral tracer accumulation in the shoulder and lower neck. The regions of radiotracer uptake corresponded to the location of human brown adipose tissue (BAT). Excessive sympathetic stimulation by high circulating catecholamine concentrations augmented the metabolic activity and tracer uptake in the BAT. This study showed that radionuclide imaging can noninvasively visualize human BAT in terms of metabolic and functional activity.

Granular cell tumor is found in various organs but is rare in the mediastinum. We report a case of 21-year-old woman with a granular cell tumor in the left upper mediastinum. Chest computed tomography (CT) showed a 30 x 20 mm well circumscribed tumor in the left upper mediastinum. Tumor resection was performed. It was found that the tumor involved the sympathetic nerve. Histopathologically, the tumor consisted of cells with eosinophilic granules and diagnosed as a granular cell tumor.

A 70-year-old woman who experienced transient left hemiparesis had 90% stenosis of the right internal carotid artery. CT revealed small low-density areas in the subcortical frontal area. Baseline cerebral blood flow was reduced, and vasoreactivity was poor in the right frontoparietal area according to I-123 IMP brain SPECT with acetazolamide. The distribution of I-123 iomazenil was normal on the delayed SPECT image but reduced in the early SPECT image, mimicking baseline cerebral blood flow. The distribution of I-123 iomazenil SPECT on the delayed image reflected the normal binding potential of the benzodiazepine receptor and thus identified viable tissue in an area of severely reduced perfusion. These findings were confirmed by positron emission tomography.

Renal dysfunction occurs occasionally after the repair of abdominal aortic aneurysm (AAA), and preoperative renal function is considered as one of the potential causes. The present study was designed to evaluate and compare renal function and risk factors of AAA patients with those of hypertensive patients.We prospectively examined 95 patients with AAA and 72 patients with essential hypertension (HT) without other cardiovascular diseases (CVD). Renal function, urinary albumin excretion (UAE) and renal scintigraphy were compared. Kidney size was calculated using ultrasonography.Serum creatinine and creatinine clearance in AAA patients was worse than in HT patients. Smoking status was more apparent in AAA patients. Renal artery stenosis occurred in 8 patients with AAA. Renal scintigraphy showed normal function in 19%, hypofunction in 69% and severe dysfunction in 12% of the AAA patients, and normal function in 42% and hypofunction in 58% of the HT patients (p0.0001). Multivariate linear regression analysis showed that renal function was related to age, UAE, CVD, smoking status and kidney size for all patients, UAE, CVD, smoking status and kidney size for AAA patients, and age and kidney size for HT patients.Renal function of AAA patients was worse than HT patients without other CVD. The risk factors for renal dysfunction were different between AAA and HT patients. These preoperative conditions may relate to the postoperative renal dysfunction seen in AAA patients.

We evaluated a male patient with chronic heart failure using Ga-67 citrate and F-18 FDG imaging to eliminate secondary dilated cardiomyopathy resulting from sarcoidosis. Tracer accumulated bilaterally in the breast tissueduring both imaging procedures. This uptake was probably the result of bilateral gynecomastia caused by therapeutic spironolactone administration in addition to standard therapy for chronic heart failure.

Adoption of standard input function (SIF) has been proposed for kinetic analysis of receptor binding potential (BP), instead of invasive frequent arterial samplings. The purpose of this study was to assess the SIF method in quantitative analysis of [123I]iomazenil (IMZ), a central benzodiazepine antagonist, for SPECT. SPECT studies were performed on 10 patients with cerebrovascular disease or Alzheimer disease. Intermittent dynamic SPECT scans were performed from 0 to 201 min after IMZ-injection. BPs calculated from SIFs obtained from normal volunteers (BPs) were compared with those of individual arterial samplings (BPo). Good correlations were shown between BP(o)s and BP(s)s in the 9 subjects, but maximum BP(s)s were four times larger than the corresponding BP(o)s in one case. There were no abnormal laboratory data in this patient, but the relative arterial input count in the late period was higher than the SIF. Simulation studies with modified input functions revealed that height in the late period can produce significant errors in estimated BPs. These results suggested that the simplified method with one-point arterial sampling and SIF can not be applied clinically. One additional arterial sampling in the late period may be useful.

Fusion of images of vascular anatomy and of myocardial perfusion images might be helpful for understanding the relationship between ischemia and the responsible vessels. The aim of this study was to develop a simple means of superimposing the images obtained from coronary angiography and gated myocardial perfusion SPECT.Right and left oblique views from conventional coronary angiography and left ventriculography (LVG) were stored as 512 x 512 x 8-bit digital datasets and combined. We reconstructed images from routine gated myocardial perfusion imaging (MPI) by using (99m)Tc-tetrofosmin to match the oblique positions between the image from MPI and combined angiographic images. We then generated a 3-dimensional (3D) surface map by using the quantitative gated SPECT (QGS)/quantitative perfusion SPECT (QPS) program. Both the combined angiographic images and the 3D surface map were rescaled and unified by registering the internal landmarks between the 2 images. After subtraction of the LVG image, the coronary angiogram and the 3D surface map were fused into 1 image. All processes were performed with the QGS/QPS program and commercially available graphic software. We applied this method to datasets from a cardiac phantom and from several patients with coronary artery disease.In the phantom study, our technique could obtain a 3D surface map in which the oblique angle was identified as that of radiography and could realize image registration and superimposition of radiography on scintigraphy. The preliminary results from the patients indicated that the markedly stenotic vessels showed good coincidence with the regional myocardial perfusion abnormalities on the unified images. In addition, these images could show the relationship between the coronary artery and regional wall motion in the gated mode.We developed a simple method of superimposing the image of the coronary artery tree on images from gated MPI. The technique yielded useful information about myocardial perfusion and function as well as the supplying coronary artery.

Because of the difficulty of predicting the response of patients with idiopathic dilated cardiomyopathy (IDC) to beta-blocker therapy, this study was performed to evaluate whether gated myocardial SPECT (gated SPECT) could be useful for predicting that response.We performed gated SPECT with (99m)Tc-sestamibi on 38 patients with IDC before treatment with a beta-blocker and standard medication. Perfusion abnormalities, left ventricular (LV) function, and spheric distortion were assessed by a quantitative software program.We classified patients into 2 groups according to improvement in LV function after 4 mo of therapy. The groups consisted of 16 poor responders whose LV ejection fraction (LVEF) increased less than 10% and 22 good responders whose LVEF increased by 10% or more. The patient characteristics before therapy, including LV volume and LVEF, did not significantly differ between the 2 groups, but the size of the myocardial perfusion defect and spheric distortion were significantly greater in poor responders than in good responders.Gated SPECT, by allowing simultaneous assessment of perfusion, function and geometry, might be useful for predicting the response of patients with IDC to beta-blocker therapy.