Small Cell Lung Cancer Staging: Prospective Comparison of Conventional Staging Tests, FDG PET/CT, Whole-Body MRI, and Coregistered FDG PET/MRI.

BACKGROUND. Whole-body MRI and FDG PET/MRI have shown encouraging results for staging of thoracic malignancy but are poorly studied for staging of small cell lung cancer (SCLC). OBJECTIVE. The purpose of our study was to compare the performance of conventional staging tests, FDG PET/CT, whole-body MRI, and FDG PET/MRI for staging of SCLC. METHODS. This prospective study included 98 patients (64 men, 34 women; median age, 74 years) with SCLC who underwent conventional staging tests (brain MRI; neck, chest, and abdominopelvic CT; and bone scintigraphy), FDG PET/CT, and whole-body MRI within 2 weeks before treatment; coregistered FDG PET/MRI was generated. Two nuclear medicine physicians independently reviewed conventional tests and FDG PET/CT examinations in separate sessions, and two chest radiologists independently reviewed whole-body MRI and FDG PET/MRI examinations in separate sessions. Readers assessed T, N, and M categories; TNM stage; and Veterans Administration Lung Cancer Study Group (VALSG) stage. Reader pairs subsequently reached consensus. Stages determined clinically during tumor board sessions served as the reference standard. RESULTS. Accuracy for T category was higher (p < .05) for whole-body MRI (94.9%) and FDG PET/MRI (94.9%) than for FDG PET/CT (85.7%). Accuracy for N category was higher (p < .05) for whole-body MRI (84.7%), FDG PET/MRI (83.7%), and FDG PET/CT (81.6%) than for conventional staging tests (75.5%). Accuracy for M category was higher (p < .05) for whole-body MRI (94.9%), FDG PET/MRI (94.9%), and FDG PET/CT (94.9%) than for conventional staging tests (84.7%). Accuracy for TNM stage was higher (p < .05) for whole-body MRI (88.8%) and FDG PET/MRI (86.7%) than for FDG PET/CT (77.6%) and conventional staging tests (72.4%). Accuracy for VALSG stage was higher (p < .05) for whole-body MRI (95.9%), FDG PET/MRI (95.9%), and FDG PET/CT (98.0%) than for conventional staging tests (82.7%). Interobserver agreement, expressed as kappa coefficients, ranged from 0.81 to 0.94 across imaging tests and staging endpoints. CONCLUSION. FDG PET/CT, whole-body MRI, and coregistered FDG PET/MRI outperformed conventional tests for various staging endpoints in patients with SCLC. Whole-body MRI and FDG PET/MRI outperformed FDG PET/CT for T category and thus TNM stage, indicating the utility of MRI for assessing extent of local invasion in SCLC. CLINICAL IMPACT. Incorporation of either MRI approach may improve initial staging evaluation in SCLC.

Entanglement and Photon Anti-Bunching in Coupled Non-Degenerate Parametric Oscillators.

We analytically and numerically show that the Hillery-Zubairy's entanglement criterion is satisfied both below and above the threshold of coupled non-degenerate optical parametric oscillators (NOPOs) with strong nonlinear gain saturation and dissipative linear coupling. We investigated two cases: for large pump mode dissipation, below-threshold entanglement is possible only when the parametric interaction has an enough detuning among the signal, idler, and pump photon modes. On the other hand, for a large dissipative coupling, below-threshold entanglement is possible even when there is no detuning in the parametric interaction. In both cases, a non-Gaussian state entanglement criterion is satisfied even at the threshold. Recent progress in nano-photonic devices might make it possible to experimentally demonstrate this phase transition in a coherent XY machine with quantum correlations.

A micrometre-scale Raman silicon laser with a microwatt threshold.

The application of novel technologies to silicon electronics has been intensively studied with a view to overcoming the physical limitations of Moore's law, that is, the observation that the number of components on integrated chips tends to double every two years. For example, silicon devices have enormous potential for photonic integrated circuits on chips compatible with complementary metal-oxide-semiconductor devices, with various key elements having been demonstrated in the past decade. In particular, a focus on the exploitation of the Raman effect has added active optical functionality to pure silicon, culminating in the realization of a continuous-wave all-silicon laser. This achievement is an important step towards silicon photonics, but the desired miniaturization to micrometre dimensions and the reduction of the threshold for laser action to microwatt powers have yet to be achieved: such lasers remain limited to centimetre-sized cavities with thresholds higher than 20 milliwatts, even with the assistance of reverse-biased p-i-n diodes. Here we demonstrate a continuous-wave Raman silicon laser using a photonic-crystal, high-quality-factor nanocavity without any p-i-n diodes, yielding a device with a cavity size of less than 10 micrometres and an unprecedentedly low lasing threshold of 1 microwatt. Our nanocavity design exploits the principle that the strength of light-matter interactions is proportional to the ratio of quality factor to the cavity volume and allows drastic enhancement of the Raman gain beyond that predicted theoretically. Such a device may make it possible to construct practical silicon lasers and amplifiers for large-scale integration in photonic circuits.

Japanese multicenter database of healthy controls for [123I]FP-CIT SPECT.

PURPOSE: The aim of this multicenter trial was to generate a [123I]FP-CIT SPECT database of healthy controls from the common SPECT systems available in Japan. METHODS: This study included 510 sets of SPECT data from 256 healthy controls (116 men and 140 women; age range, 30-83 years) acquired from eight different centers. Images were reconstructed without attenuation or scatter correction (NOACNOSC), with only attenuation correction using the Chang method (ChangACNOSC) or X-ray CT (CTACNOSC), and with both scatter and attenuation correction using the Chang method (ChangACSC) or X-ray CT (CTACSC). These SPECT images were analyzed using the Southampton method. The outcome measure was the specific binding ratio (SBR) in the striatum. These striatal SBRs were calibrated from prior experiments using a striatal phantom. RESULTS: The original SBRs gradually decreased in the order of ChangACSC, CTACSC, ChangACNOSC, CTACNOSC, and NOACNOSC. The SBRs for NOACNOSC were 46% lower than those for ChangACSC. In contrast, the calibrated SBRs were almost equal under no scatter correction (NOSC) conditions. A significant effect of age was found, with an SBR decline rate of 6.3% per decade. In the 30-39 age group, SBRs were 12.2% higher in women than in men, but this increase declined with age and was absent in the 70-79 age group. CONCLUSIONS: This study provided a large-scale quantitative database of [123I]FP-CIT SPECT scans from different scanners in healthy controls across a wide age range and with balanced sex representation. The phantom calibration effectively harmonizes SPECT data from different SPECT systems under NOSC conditions. The data collected in this study may serve as a reference database.

Nuclear medicine practice in Japan: a report of the ninth nationwide survey in 2022.

Subcommittee on Survey of Nuclear Medicine Practice in Japan has performed a nationwide survey of nuclear medicine practice every 5 years since 1982 to survey contemporary nuclear medicine practice and its changes over the years. The subcommittee sent questionnaires, including the number and category of examinations as well as the kind of the radiopharmaceuticals during the 30 days of June 2022 to all nuclear medicine institutes in Japan. The total numbers of them for the year 2022 were estimated depends on the 1-month data. A total of 1095 institutes responded to the survey, including 364 positron emission tomography (PET) centers. The recovery rate was 90.6%. The number of gamma cameras installed was 1299 in total, with 2.5% decrease in 5 years. Dual-head cameras and hybrid SPECT/CT scanners accounted for 83.8% and 35.5%, respectively. The number of single-photon tracer studies in 2022 was 1.11 million which means increase in 2.7% in 5 years. Bone scintigraphy was a leading examination (31.0%), followed by myocardial scintigraphy (27.1%) and cerebral perfusion study (23.8%) in order. The percentage of SPECT studies showed an increase from 63.5% in previous survey to 66.8% in this survey. PET centers have also increased from 389 to 412, as compared with the previous one. One hundred and twenty-two PET centers have installed one or two in-house cyclotrons. Increasing trends of the PET studies were observed from 1992 to 2017, the trend changed and PET studies showed 1.5% decrease in 5 years. 18F-FDG accounted for 98.6% (610,497 examinations). PET examinations using 11C-methionine, 13N-NH3 and 11C-PIB have decreased, with 1624, 2146 and 525 examinations, respectively in 2022. The total number of nuclear medicine examination was eventually increased by 1.0%. Therapies for pheochromocytoma or paraganglioma (PPGL) with 131I-MIBG and for neuroendocrine tumor with 177Lu-DOTA-TATE were newly started, however, a total number of targeted radionuclide therapy was decreased by 17.7% because 131I-radioiodine and 223Ra targeted therapies were decreased and supply of some radioisotopes was discontinued. 131I-radioiodine targeted therapy showed a decrease in 5 years (- 15.9%), including 4099 patients for thyroid cancer. The number of out-patient thyroid bed ablation therapy with 1110 MBq of 131I was also decreased to 1015 per year. The number of admission rooms specialized for radionuclide targeted therapy increased from 157 to 160. The number of 223Ra targeted therapies for castration-resistant metastatic prostate cancer (mCRPC) was 1041 patients. This survey was performed during COVID-19 pandemic, however, total number of nuclear medicine examinations was almost same as previous survey (+ 1.0%). Radionuclide therapies with 131I-MIBG and 177Lu-DOTA-TATE were newly started, and new radionuclide therapy will be available in future, therefore, the development of radionuclide therapy will be continued. We are convinced that this survey report is useful in understanding the current status of the nuclear medicine practice in Japan, and in devising the new strategy to strengthen a role of nuclear medicine.

Examination of postmortem changes in the lungs, trachea, and bronchi in a rat model imaged with small-animal computed tomography.

Objectives: As less autopsies are performed, the need for postmortem computed tomography (PMCT) as an alternative is increasing. It is important to know how postmortem changes over time are reflected on CT, in order to improve the diagnostic capability of PMCT and replace forensic pathology evaluations such as time of death estimation. Methods: In this study, we examined temporal changes on postmortem chest CT images of a rat model. After acquiring antemortem images under isoflurane inhalation anesthesia, the rats were euthanized with a rapid intravenous injection of anesthetics. From immediately after death to 48 hours postmortem, chest images were acquired using small-animal CT. The 3D images were then evaluated on a workstation to measure the antemortem and postmortem air content in the lungs, trachea, and bronchi over time. Results: The air content in the lungs decreased, but the air content of the trachea and bronchi temporarily increased 1-12 hours postmortem, then decreased at 48 hours postmortem. Therefore, the measurement of trachea and bronchi volumes on PMCT could be an objective way to estimate the time of death. Conclusions: While the air content of the lungs decreased, the volume of the trachea and bronchi temporarily increased after death, indicating the potential to use such measurements to estimate time of death.

Effective implementation of [Formula: see text]-regularised compressed sensing with chaotic-amplitude-controlled coherent Ising machines.

Coherent Ising machine (CIM) is a network of optical parametric oscillators that can solve large-scale combinatorial optimisation problems by finding the ground state of an Ising Hamiltonian. As a practical application of CIM, Aonishi et al., proposed a quantum-classical hybrid system to solve optimisation problems of [Formula: see text]-regularisation-based compressed sensing. In the hybrid system, the CIM was an open-loop system without an amplitude control feedback loop. In this case, the hybrid system is enhanced by using a closed-loop CIM to achieve chaotic behaviour around the target amplitude, which would enable escaping from local minima in the energy landscape. Both artificial and magnetic resonance image data were used for the testing of our proposed closed-loop system. Compared with the open-loop system, the results of this study demonstrate an improved degree of accuracy and a wider range of effectiveness.

Ultrahigh-Q photonic crystal nanocavities in wide optical telecommunication bands.

We have studied the feasibility of extending the operating wavelength range of high-Q silicon nanocavities above and below the 1.55 µm wavelength band, while maintaining Q factors of more than one million. We have succeeded in developing such nanocavities in the optical telecommunication bands from 1.27 µm to 1.50 µm. Very high Q values of more than two million were obtained even for the 1.30 µm band. The Q values increase proportionally to the resonant wavelength because the scattering loss decreases. We have also analyzed the influence of absorption due to surface water. We conclude that high-Q nanocavities are feasible for an even wider wavelength region including parts of the mid-infrared.

Design and synthesis of novel DFG-out RAF/vascular endothelial growth factor receptor 2 (VEGFR2) inhibitors: 2. Synthesis and characterization of a novel imide-type prodrug for improving oral absorption.

As an alternative to the previously reported solid dispersion formulation for enhancing the oral absorption of thiazolo[5,4-b]pyridine 1, we investigated novel N-acyl imide prodrugs of 1 as RAF/vascular endothelial growth factor receptor 2 (VEGFR2) inhibitors. Introducing N-acyl promoieties at the benzanilide position gave chemically stable imides. N-tert-Butoxycarbonyl (Boc) introduced imide 6 was a promising prodrug, which was converted to the active compound 1 after its oral administration in mice. Cocrystals of 6 with AcOH (6b) possessed good physicochemical properties with moderate thermodynamic solubility (19µg/mL). This crystalline prodrug 6b was rapidly and enzymatically converted into 1 after its oral absorption in mice, rats, dogs, and monkeys. Prodrug 6b showed in vivo antitumor regressive efficacy (T/C=-6.4%) in an A375 melanoma xenograft model in rats. Hence, we selected 6b as a promising candidate and are performing further studies. Herein, we report the design, synthesis, and characterization of novel imide-type prodrugs.

Effect of cognitive reserve on amnestic mild cognitive impairment due to Alzheimer's disease defined by fluorodeoxyglucose-positron emission tomography.

This study aimed to investigate the effect of cognitive reserve (CR) on the rate of cognitive decline and cerebral glucose metabolism in amnestic mild cognitive impairment (MCI) using the Study on Diagnosis of Early Alzheimer's Disease-Japan (SEAD-J) dataset. The patients in SEAD-J underwent cognitive tests and fluorodeoxyglucose-positron emission tomography (FDG-PET). MCI to be studied was classified as amnestic MCI due to Alzheimer's disease (AD) with neurodegeneration. A total of 57 patients were visually interpreted as having an AD pattern (P1 pattern, Silverman's classification). The 57 individuals showing the P1 pattern were divided into a high-education group (years of school education ≥13, N = 18) and a low-education group (years of school education ≤12, N = 39). Voxel-based statistical parametric mapping revealed more severe hypometabolism in the high-education group than in the low-education group. Glucose metabolism in the hippocampus and temporoparietal area was inversely associated with the years of school education in the high- and low-education groups (N = 57). General linear mixed model analyses demonstrated that cognitive decline was more rapid in the high-education group during 3-year follow-up. These results suggest that the cerebral glucose metabolism is lower and cognitive function declines faster in patients with high CR of amnestic MCI due to AD defined by FDG-PET.

Voxel-based analysis of age and gender effects on striatal [123I] FP-CIT binding in healthy Japanese adults.

OBJECTIVE: Although previous studies have investigated age and gender effects on striatal subregional dopamine transporter (DaT) binding, these studies were mostly based on a conventional regions of interest-based analysis. Here, we investigated age and gender effects on striatal DaT binding at the voxel level, using a multicenter database of [(123)I] N-omega-fluoropropyl-2beta-carbomethoxy-3beta-{4-iodophenyl}nortropane ([(123)I] FP-CIT)-single photon emission computed tomography (SPECT) scans in 256 healthy Japanese adults. METHODS: We used the Southampton method to calculate the specific binding ratios (SBRs) of each subject's striatum and then converted the [123I] FP-CIT SPECT images to quantitative SBRs images. To investigate the effects of age and gender effects on striatal DaT binding, we performed a voxel-based analysis using statistical parametric mapping. Gender differences were also compared between young to middle-aged subjects and elderly subjects (age threshold: 60 years). RESULTS: When all subjects were explored as a group, DaT binding throughout the striatum decreased with advancing age. Among all subjects, the females showed higher DaT binding in the bilateral caudate compared to the males. In the young to middle-aged subjects, the females showed higher DaT binding throughout the striatum (with a slight caudate predominance) versus the males. In the elderly, there were no gender differences in striatal DaT binding. CONCLUSION: Our findings of striatal subregional age- and gender-related differences may provide useful information to construct a more detailed DaT database in healthy Japanese subjects.

Automated classification of increased uptake regions in bone single-photon emission computed tomography/computed tomography images using three-dimensional deep convolutional neural network.

OBJECTIVE: This study proposes an automated classification of benign and malignant in highly integrated regions in bone single-photon emission computed tomography/computed tomography (SPECT/CT) using a three-dimensional deep convolutional neural network (3D-DCNN). METHODS: We examined 100 regions of 35 patients with bone SPECT/CT classified as benign and malignant by other examinations and follow-ups. First, SPECT and CT images were extracted at the same coordinates in a cube, with a long side two times the diameter of a high concentration in SPECT images. Next, we inputted the extracted image to DCNN and obtained the probability of benignity and malignancy. Integrating the output from DCNN of each SPECT and CT image provided the overall result. To validate the efficacy of the proposed method, the malignancy of all images was assessed using the leave-one-out cross-validation method; besides, the overall classification accuracy was evaluated. Furthermore, we compared the analysis results of SPECT/CT, SPECT alone, CT alone, and whole-body planar scintigraphy in the highly integrated region of the same site. RESULTS: The extracted volume of interest was 50 benign and malignant regions, respectively. The overall classification accuracy of SPECT alone and CT alone was 73% and 68%, respectively, while that of the whole-body planar analysis at the same site was 74%. When SPECT/CT images were used, the overall classification accuracy was the highest (80%), while the classification accuracy of malignant and benign was 82 and 78%, respectively. CONCLUSIONS: This study suggests that DCNN could be used for the direct classification of benign and malignant regions without extracting the features of SPECT/CT accumulation patterns.

Clinical utility of the normal database of 123I-iodoamphetamine brain perfusion single photon emission computed tomography for statistical analysis using computed tomography-based attenuation correction: a multicenter study.

OBJECTIVES: We have established a common normal database (NDB) with applicability in multicenter settings for the statistical analysis of brain perfusion single photon emission computed tomography (SPECT) with triple energy window scatter correction, computed tomography-based attenuation correction (CTAC), and spatial resolution compensation. This study aimed to compare the CTAC normal database (CTAC-NDB) with conventional normal databases for the statistical analysis of 123I-iodoamphetamine (123I-IMP) brain perfusion SPECT at three institutions and to assess the clinical efficiency of CTAC-NDB. METHODS: We recruited 45 patients (26 men and 19 women; mean age, 74.2 ± 3.9 years; Mini-Mental State Examination score, 19.8 ± 6.1) with Alzheimer's disease (AD, n = 26), dementia with Lewy bodies (DLB, n = 9), and mild cognitive impairment (n = 10) from three institutions. Three-dimensional stereotactic surface projection (3D-SSP) technique was used to analyze data obtained from the 123I-IMP brain perfusion SPECT images compared with both CTAC-NDB and conventional NDB. We visually assessed each 3D-SSP z score map to determine the changes in specific findings, such as AD/DLB pattern. Furthermore, the stereotactic extraction estimation analysis software was used to measure the regional z score severity and extent as a semiquantitative assessment. RESULTS: In the visual assessment, all cases exhibited clearer findings with CTAC-NDB than with conventional NDB in the parietotemporal association cortex as well as in the inferior temporal, frontal, and lateral occipital cortices. Contrarily, the findings from the medial cerebral regions, including the precuneus and the posterior cingulate, became indistinct in 71% of the cases and remained unchanged in 25% of the cases. In the semiquantitative analysis, a similar tendency was observed in the mean z score in the three institutions included in the study. CONCLUSION: Using the CTAC-NDB, the findings in the vicinity of the cranium became increasingly clear, whereas those in the medial surface of the brain became less defined or remained unchanged. These findings were confirmed via a semiquantitative analysis. Moreover, similar changes in the reduction pattern were observed in the three institutions. Therefore, the new database with CTAC might be applicable in other institutions. Data collected in this study may serve as a CTAC-NDB.

Microliter-ordered automatic blood sampling system for fully quantitative analysis of small-animal PET.

OBJECTIVE: The objective of the present study was to develop a fully automated blood sampling system for kinetic analysis in mice positron emission tomography (PET) studies. Quantitative PET imaging requires radioactivity concentrations in arterial plasma to estimate the behavior of an administered radiopharmaceutical in target organs. Conventional manual blood sampling has several drawbacks, such as the need for troubleshooting in regard to blood collection, necessary personnel, and the radiation exposure dose. We recently developed and verified the operability of a fully automated blood sampling system (automatic blood dispensing system-ABDS). Here, we report the results of fully quantitative measurements of the cerebral metabolic rate of glucose (CMRglc) in mice using the ABDS. METHODS: Under 1% isoflurane anesthesia, a catheter was inserted into the femoral artery of nine wild-type male mice. Immediately after injection of 18F-fluorodeoxyglucose (FDG) (13.2 ± 3.93 MBq in 0.1 mL saline), arterial blood samples were drawn using the ABDS and then analyzed using CD-Well, a system we previously developed that can measure radioactivity concentration (Bq/µL) using a few microliters of blood in the plasma and whole blood separately. In total, 16 blood samplings were conducted in 60 min as follows: 10 s × 9; 70 s × 2; 120 s × 1; 250 s × 1; 10 min × 2; and 30 min × 1. Dynamic PET scans were conducted concurrently using a small-animal PET/computed tomography (CT) (PET/CT) scanner. Full kinetics modeling using a two-tissue-three-compartment model was applied to calculate CMRglc. Blood volume was also estimated. RESULTS: No significant differences were observed between the manual and ABDS measurements. A proportional error was detected only for plasma. The mean ± standard deviation CMRglc value in the mice was 5.43 ± 1.98 mg/100 g/min (30.2 ± 11 µmol/min/100 g), consistent with a previous report. CONCLUSIONS: The automated microliter-ordered blood sampling system developed in the present study appears to be useful for absolute quantification of CMRglc in mice PET studies.

Reliability of diagnosing acute ischemic cerebrovascular on magnetic resonance imaging disorders using iPads.

PURPOSE: The use of tablet terminals has been explored in various medical settings; however, caution should be exercised when performing image diagnosis using this technology. The present study examined the characteristics of an iPad Air™ monitor and assessed radiographic image interpretations to verify the reliability of the telediagnosis of acute cerebral infarction based on magnetic resonance imaging (MRI) using a tablet terminal. MATERIALS AND METHODS: The luminance of the iPad Air™ was measured using a UA-10 analyzer, and radiographic image interpretation experiments were performed in 100 patients who underwent MRI within 6 h of symptom onset. Ten physicians viewed the images on the iPad Air™ and a medical monitor, with an interval of 2 months between each interpretation. RESULTS: When the iPad Air™ screen was pure white, the contour lines revealed nonuniform luminance distribution. In the reading experiment, the areas under the curve of the medical monitor and the iPad Air™ were 0.9311 and 0.9431, respectively. No significant difference was observed between the medical monitor and the iPad Air™ (p = 0.113). CONCLUSION: The results of the observer performance studies for detecting acute ischemic cerebrovascular disorders on an iPad Air™ were found to be similar to those on a medical monitor.

CT-based attenuation correction and resolution compensation for I-123 IMP brain SPECT normal database: a multicenter phantom study.

OBJECTIVE: Statistical image analysis of brain SPECT images has improved diagnostic accuracy for brain disorders. However, the results of statistical analysis vary depending on the institution even when they use a common normal database (NDB), due to different intrinsic spatial resolutions or correction methods. The present study aimed to evaluate the correction of spatial resolution differences between equipment and examine the differences in skull bone attenuation to construct a common NDB for use in multicenter settings. METHODS: The proposed acquisition and processing protocols were those routinely used at each participating center with additional triple energy window (TEW) scatter correction (SC) and computed tomography (CT) based attenuation correction (CTAC). A multicenter phantom study was conducted on six imaging systems in five centers, with either single photon emission computed tomography (SPECT) or SPECT/CT, and two brain phantoms. The gray/white matter I-123 activity ratio in the brain phantoms was 4, and they were enclosed in either an artificial adult male skull, 1300 Hounsfield units (HU), a female skull, 850 HU, or an acrylic cover. The cut-off frequency of the Butterworth filters was adjusted so that the spatial resolution was unified to a 17.9 mm full width at half maximum (FWHM), that of the lowest resolution system. The gray-to-white matter count ratios were measured from SPECT images and compared with the actual activity ratio. In addition, mean, standard deviation and coefficient of variation images were calculated after normalization and anatomical standardization to evaluate the variability of the NDB. RESULTS: The gray-to-white matter count ratio error without SC and attenuation correction (AC) was significantly larger for higher bone densities (p < 0.05). The count ratio error with TEW and CTAC was approximately 5% regardless of bone density. After adjustment of the spatial resolution in the SPECT images, the variability of the NDB decreased and was comparable to that of the NDB without correction. CONCLUSION: The proposed protocol showed potential for constructing an appropriate common NDB from SPECT images with SC, AC and spatial resolution compensation.

Evaluation of probable or possible dementia with lewy bodies using 123I-IMP brain perfusion SPECT, 123I-MIBG, and 99mTc-MIBI myocardial SPECT.

UNLABELLED: We evaluated the diagnostic usefulness of combination studies with a statistical mapping method in N-isopropyl-p-(123)I-iodoamphetamine ((123)I-IMP) brain perfusion SPECT, cardiac sympathetic nerve function by (123)I-metaiodobenzylguanidine ((123)I-MIBG), and myocardial function by electrocardiographically gated (99m)Tc-sestamibi ((99m)Tc-MIBI) SPECT for patients with probable or possible dementia with Lewy bodies (DLB). METHODS: Twelve patients with probable DLB (7 male, 5 female; mean age +/- SD, 72.3 +/- 5.63 y; range, 65-82 y) and 9 patients with possible DLB (3 male, 6 female; mean age +/- SD, 73.1 +/- 9.23 y; range, 59-88 y) were enrolled in this study. (123)I-IMP SPECT images were analyzed with 3-dimensional stereotactic surface projections (3D-SSP) and the severity of ischemia was classified objectively using quantitatively analytic and display software; stereotactic extraction estimation (SEE) methods were compared with a normal database. In addition, we evaluated (123)I-MIBG heart-to-mediastinum (H/M) uptake ratios. Moreover, we performed (99m)Tc-MIBI SPECT to evaluate myocardial perfusion and the left ventricular ejection fraction (LVEF) compared with a normal database. RESULTS: 3D-SSP images of group comparison with healthy control subjects showed significantly decreased perfusion in the parietotemporal, occipital cortex, posterior cingulated, and precuneus regions in the probable DLB group but no significant reduction in the possible DLB group. Mean H/M ratios in the probable DLB group were significantly lower than those of the possible DLB group and the control group, respectively. Ten of 12 patients (83.3%) with probable DLB and 1 of 9 patients (11.1%) with possible DLB showed severe reduction in the bilateral occipital lobe and also a low (123)I-MIBG uptake. One patient (8.3%) with probable DLB and 2 patients (22.2%) with possible DLB showed no bilateral occipital hypoperfusion but showed low (123)I-MIBG uptake. One patient (8.3%) with probable DLB and 6 patients (66.7%) with possible DLB showed no occipital hypoperfusion and normal (123)I-MIBG uptake. (99m)Tc-MIBI gated SPECT did not indicate any wall motion abnormality in any subjects. CONCLUSION: These results suggest that combined examination of cerebral blood flow with 3D-SSP and SEE analysis, and cardiac sympathetic nerve function with (123)I-MIBG, would be a useful supporting diagnostic method in patients with DLB-particularly, in possible DLB and when cerebral blood flow does not indicate occipital hypoperfusion.

Longer-Term Investigation of the Value of 18F-FDG-PET and Magnetic Resonance Imaging for Predicting the Conversion of Mild Cognitive Impairment to Alzheimer's Disease: A Multicenter Study.

BACKGROUND: The value of fluorine-18-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) and magnetic resonance imaging (MRI) for predicting conversion of mild cognitive impairment (MCI) to Alzheimer's disease (AD) in longer-term is unclear. OBJECTIVE: To evaluate longer-term prediction of MCI to AD conversion using 18F-FDG-PET and MRI in a multicenter study. METHODS: One-hundred and fourteen patients with MCI were followed for 5 years. They underwent clinical and neuropsychological examinations, 18F-FDG-PET, and MRI at baseline. PET images were visually classified into predefined dementia patterns. PET scores were calculated as a semi quantitative index. For structural MRI, z-scores in medial temporal area were calculated by automated volume-based morphometry (VBM). RESULTS: Overall, 72% patients with amnestic MCI progressed to AD during the 5-year follow-up. The diagnostic accuracy of PET scores over 5 years was 60% with 53% sensitivity and 84% specificity. Visual interpretation of PET images predicted conversion to AD with an overall 82% diagnostic accuracy, 94% sensitivity, and 53% specificity. The accuracy of VBM analysis presented little fluctuation through 5 years and it was highest (73%) at the 5-year follow-up, with 79% sensitivity and 63% specificity. The best performance (87.9% diagnostic accuracy, 89.8% sensitivity, and 82.4% specificity) was with a combination identified using multivariate logistic regression analysis that included PET visual interpretation, educational level, and neuropsychological tests as predictors. CONCLUSION: 18F-FDG-PET visual assessment showed high performance for predicting conversion to AD from MCI, particularly in combination with neuropsychological tests. PET scores showed high diagnostic specificity. Structural MRI focused on the medial temporal area showed stable predictive value throughout the 5-year course.

123I-metaiodobenzylguanidine myocardial scintigraphy with early images alone is useful for the differential diagnosis of dementia with Lewy bodies.

123I-metaiodobenzylguanidine cardiac scintigraphy (MIBG) is a useful imaging technique for the diagnosis of dementia with Lewy bodies (DLB). However, MIBG has a serious disadvantage in that it demands a long examination time. The objective of this study was to evaluate statistically the usefulness of the heart/mediastinum ratio (H/M) from the early phase of MIBG for the differential diagnosis of DLB. In total, 113 patients were examined, including 32 non-DLB (19 with Alzheimer's dementia) and 79 DLB patients. The mean early-H/M ratio was 2.83 in the non-DLB group and 1.95 in the DLB group. The mean delayed-H/M ratio was 3.0 in the non-DLB group and 1.76 in the DLB group. With a cutoff point of 2.27 on early images, the sensitivity, specificity, and diagnostic accuracy were 65%, 94%, and 73%, respectively, and the area under the curve was 0.82, indicating moderate accuracy. This analysis indicates that images from the early phase of MIBG alone are sufficient for the differential diagnosis of Alzheimer's disease and DLB.

Brain fluorodeoxyglucose (FDG) PET in dementia.

The purpose of this article is to present a selective and concise summary of fluorodeoxyglucose (FDG) positron emission tomography (PET) in dementia imaging. FDG PET is used to visualize a downstream topographical marker that indicates the distribution of neural injury or synaptic dysfunction, and can identify distinct phenotypes of dementia due to Alzheimer's disease (AD), Lewy bodies, and frontotemporal lobar degeneration. AD dementia shows hypometabolism in the parietotemporal association area, posterior cingulate, and precuneus. Hypometabolism in the inferior parietal lobe and posterior cingulate/precuneus is a predictor of cognitive decline from mild cognitive impairment (MCI) to AD dementia. FDG PET may also predict conversion of cognitively normal individuals to those with MCI. Age-related hypometabolism is observed mainly in the anterior cingulate and anterior temporal lobe, along with regional atrophy. Voxel-based statistical analyses, such as statistical parametric mapping or three-dimensional stereotactic surface projection, improve the diagnostic performance of imaging of dementias. The potential of FDG PET in future clinical and methodological studies should be exploited further.