Phantom-Based Standardization Method for 123I-metaiodobenzylguanidine Heart-to-Mediastinum Ratio Validated by D-SPECT Versus Anger Camera.

Background: The 123I-metaiodobenzylguanidine heart-to-mediastinum ratios (HMRs) have been standardized between D-SPECT and Anger cameras in a small patient cohort using a phantom-based conversion method. This study aimed to determine the validity of this method and compare the diagnostic performance of the two cameras in a larger patient cohort. Methods: We retrospectively calculated HMRs from early and late anterior-planar equivalent and planar images acquired from 173 patients in 177 studies using D-SPECT and Anger cameras, respectively. The D-SPECT HMRs were cross-calibrated to an Anger camera using conversion coefficients based on previous phantom findings, then standardized to medium-energy general-purpose collimator conditions. Relationships between HMRs before and after corrections were investigated. Late HMRs were classified into four cardiac mortality risk groups and divided into two groups using a threshold of 2.2 to verify diagnostic performance concordance. Results: Correction improved linear regression lines and differences in HMRs among the groups. The overall ratios of perfect concordance were (134 [75.7%] of 177), and higher in groups with very low (49 [80.3%] of 61) and high (51 [86.4%] of 59) HMRs when the standardized HMR was classified according to cardiac mortality risk. That between the systems was the highest (164 [92.7%] of 177) when the HMR was divided by a threshold value of 2.2. Conclusions: Phantom-based conversion can standardize HMRs between D-SPECT and Anger cameras because the standardized HMR provided comparable diagnostic performance. Our findings indicated that this conversion could be applied to multicenter studies that include both D-SPECT and Anger cameras.

Exercise program to reduce the risk of cognitive decline and physical frailty in older adults: study protocol for an open label double-arm clinical trial.

Objective: It is a big problem that many older adults are physically inactive. Well-known benefits of physical exercise include a decrease in the risk of cognitive decline and physical frailty. Therefore, this study aims to examine whether our proposed exercise program can prevent cognitive decline and improve physical function in the elderly. Methods: This study will include nondemented older adults (n = 103) without regular exercise habits. The trial will include a physical exercise training program (once a week) and nutritional lectures (once a month) over 5 months and follow-up for ≥1 year. The primary endpoint is the program's efficacy in preventing cognitive decline, as assessed by changes in the memory performance index of the mild cognitive impairment (MCI) screen; the secondary endpoints are the incidence of MCI and dementia, physical testing, and frailty proportion. In the exploratory phase of the study, we will elucidate the underlying diseases causing MCI in community-dwelling older adults by neuroimaging. Discussion: This double-arm trial that aims to assess the impact of physical exercise on nondemented older adults' cognitive and physical function. Furthermore, our newly developed exercise program will be easy for older adults to undertake.Clinical Trial Registration: https://clinicaltrials.gov/, identifier [jRCT 1040220140].

Modified signal-to-noise ratio in the liver using the background-to-lung activity ratio to assess image quality of whole-body 18F-fluorodeoxyglucose positron emission tomography.

The signal-to-noise ratio in the liver (SNR liver) is commonly used to assess the quality of positron emission tomography (PET) images; however, it is weakly correlated with visual assessments. Conversely, the noise equivalent count (NEC) density showed a strong correlation with visual assessment but did not consider the effects of image reconstruction conditions. Therefore, we propose a new indicator, the modified SNR liver, and plan to verify its usefulness by comparing it with conventional indicators. We retrospectively analyzed 103 patients who underwent whole-body PET/computed tomography (CT). Approximately 60 min after the intravenous injection of 18F-fluorodeoxyglucose (FDG), the participants were scanned for 2 min/bed. The SNR liver and NEC density were calculated according to the Japanese guidelines for oncology FDG-PET/CT. The modified SNR live was calculated by multiplying the background-to-lung activity ratio by the SNR liver. Patients were classified into groups based on body mass index (BMI) and visual scores. Subsequently, the relationships between these physical indicators, BMI, and visual scores were evaluated. Although the relationship between the modified SNR liver and BMI was inferior to that of NEC density and BMI, the modified SNR liver distinguished the BMI groups more clearly than the conventional SNR liver. Additionally, the modified SNR liver distinguished low visual scores from high scores more accurately than the conventional SNR liver and NEC density. Whether the modified SNR liver is more suitable than the NEC density remains equivocal; however, the modified SNR liver may be superior to the conventional SNR liver for image-quality assessment.

The Visceral-to-subcutaneous Adipose Tissue Area Ratio Is Associated with Retreatment in Chronic Pancreatitis Patients with Pancreatolithiasis after Extracorporeal Shock Wave Lithotripsy.

Objective Extracorporeal shock wave lithotripsy (ESWL) has been used to treat pancreatolithiasis in patients with chronic pancreatitis (CP), but the high recurrence rate remains challenging. We therefore evaluated the association between body composition parameters and the prediction of retreatment after ESWL. Methods This study retrospectively evaluated 42 patients with CP who had been treated with ESWL between 2008 and 2019 in a single center. Body composition parameters were measured on pretreatment computed tomography images. Patients who underwent repeat ESWL were classified as the retreatment group. Results There were 13 (31.0%) and 29 (69.0%) patients in the retreatment and non-retreatment groups, respectively. The visceral-to-subcutaneous adipose tissue area ratio (VSR) of the retreatment group was significantly lower than that of the non-retreatment group (p=0.016). When divided by the median VSR, 10 of the 20 patients with a VSR of <0.85 underwent retreatment, whereas 3 of the 22 patients with a VSR of ≥0.85 underwent retreatment (p=0.019). According to a multivariate analysis, the VSR (p=0.010) and age (p=0.037) were independent factors associated with retreatment after ESWL. Conclusion This study showed that the VSR can predict the retreatment of patients with CP after ESWL.

Beads phantom for evaluating heterogeneity of SUV on 18F-FDG PET images.

PURPOSE: This study aimed to develop a dedicated phantom using acrylic beads for texture analysis and to represent heterogeneous 18F-fluorodeoxyglucose (FDG) distributions in various acquisition periods. METHODS: Images of acrylic spherical beads with or without diameters of 5- and 10-mm representing heterogeneous and homogeneous 18F-FDG distribution in phantoms, respectively, were collected for 20 min in list mode. Phantom data were reconstructed using three-dimensional ordered subset expectation maximization with attenuation and scatter corrections, and the time-of-flight algorithm. The beads phantom images were acquired twice to evaluate the robustness of texture features. Thirty-one texture features were extracted, and the robustness of texture feature values was evaluated by calculating the percentage of coefficient of variation (%COV) and intraclass coefficient of correlation (ICC). Cross-correlation coefficients among texture feature values were clustered to classify the characteristics of these features. RESULTS: Heterogeneous 18F-FDG distribution was represented by the beads phantom images. The agreements of %COV between two measurements were acceptable (ICC ≥ 0.71). All texture features were classified into four groups. Among 31 texture features, 24 exhibited significant different values between phantoms with and without beads in 1-, 2-, 3-, 4-, 5-, 20-min image acquisitions. Whereas, the homogeneous and heterogeneous 18F-FDG distribution could not be discriminated by seven texture features: low gray-level run emphasis, high gray-level run emphasis, short-run low gray-level emphasis, low gray-level zone emphasis, high gray-level zone emphasis, short-zone low gray-level emphasis, and coarseness. CONCLUSIONS: We have developed the acrylic beads phantom for texture analysis that could represent heterogeneous 18F-FDG distributions in various acquisition periods. Most texture features could discriminate homogeneous and heterogeneous 18F-FDG distributions in the beads phantom images.

Hydrogen-producing small intestinal bacterial overgrowth is associated with hepatic encephalopathy and liver function.

Overt hepatic encephalopathy (HE) is one of the complications of liver cirrhosis (LC), which negatively affects the prognosis and quality of life of patients. Small intestinal bacterial overgrowth (SIBO) is significantly associated with LC and its complications, including HE. We investigated the relationship between SIBO and LC, and the difference between hydrogen-producing and methane-producing SIBO (H-SIBO and M-SIBO, respectively). This is a prospective cohort study of 107 cases. Breath measurements of hydrogen and methane concentrations were performed for the diagnosis of SIBO. The study cohort included 81 males with a median age of 70 (40-86) years, and SIBO was detected in 31 cases (29.0%). There were no significant differences between the SIBO positive and SIBO negative groups. Reclassification into H-SIBO (16 cases) and others (91 cases) was performed, and the Child-Pugh score was only derived in the multivariate logistic analysis (P = 0.028, odds ratio 1.39, 95% confidence interval 1.04-1.85). Furthermore, H-SIBO was significantly associated with covert HE in chi-square test (50.0% vs. 24.2%, P = 0.034). In addition, we evaluated the therapeutic response on SIBO of rifaximin in eight covert HE patients. 20% patients with M-SIBO and 67% patients with H-SIBO showed an improvement of the breath test. In conclusion, H-SIBO, but not M-SIBO, is significantly associated with liver function, and rifaximin might be more effective for covert HE with H-SIBO. Therefore, the diagnosis of SIBO, including the classification as H-SIBO and M-SIBO, might help to determine the choice of treatment for HE.

Texture Feature Comparison Between Step-and-Shoot and Continuous-Bed-Motion 18F-FDG PET.

Our objective was to investigate the differences in texture features between step-and-shoot (SS) and continuous-bed-motion (CBM) imaging in phantom and clinical studies. Methods: A National Electrical Manufacturers Association body phantom was filled with 18F-FDG solution at a sphere-to-background ratio of 4:1. SS and CBM were performed using the same acquisition duration, and the data were reconstructed using 3-dimensional ordered-subset expectation maximization with time-of-flight algorithms. Texture features were extracted using the software LIFEx. A volume of interest was delineated on the 22-, 28-, and 37-mm spheres with a threshold of 42% of the maximum SUV. The voxel intensities were discretized using 2 resampling methods, namely a fixed bin size and a fixed bin number discretization. The discrete resampling values were set to 64 and 128. In total, 31 texture features were calculated with gray-level cooccurrence matrix (GLCM), gray-level run length matrix, neighborhood gray-level different matrix, and gray-level zone length matrix. The texture features of the SS and CBM images were compared for all settings using the paired t test and the coefficient of variation. In a clinical study, 27 lesions from 20 patients were examined using the same acquisition and image processing as were used during the phantom study. The percentage difference (%Diff) and correlation between the texture features from SS and CBM images were calculated to evaluate agreement between the 2 scanning techniques. Results: In the phantom study, the 11 features exhibited no significant difference between SS and CBM images, and the coefficient of variation was no more than 10%, depending on resampling conditions, whereas entropy and dissimilarity from GLCM fulfilled the criteria for all settings. In the clinical study, the entropy and dissimilarity from GLCM exhibited a low %Diff and excellent correlation in all resampling conditions. The %Diff of entropy was lower than that of dissimilarity. Conclusion: Differences between the texture features of SS and CBM images varied depending on the type of feature. Because entropy for GLCM exhibits minimal differences between SS and CBM images irrespective of resampling conditions, entropy may be the optimal feature to reduce the differences between the 2 scanning techniques.

Comparison of 18F-FDG PET/CT and 67Ga-SPECT for the diagnosis of fever of unknown origin: a multicenter prospective study in Japan.

OBJECTIVE: The aim of this multicenter prospective study was to compare the sensitivity of 18F-fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) with that of 67Ga single photon emission computed tomography (SPECT) for the identification of the site of greatest importance for the final diagnosis of the cause of fever of unknown origin (FUO). METHODS: The study participants consisted of patients with an axillary temperature ≥ 38.0 °C on ≥ 2 occasions within 1 week, with repeated episodes for ≥ 2 weeks prior to providing consent, and whose final diagnosis after undergoing specific examinations, including a chest-to-abdomen CT scan, was uncertain. All the patients underwent FDG-PET/CT imaging first, followed by 67Ga-SPECT imaging within 3 days. The results of the FDG-PET/CT and 67Ga-SPECT examinations were reviewed by the central image interpretation committee (CIIC), which was blinded to all other clinical information. The sensitivities of FDG-PET/CT and 67Ga-SPECT were then evaluated with regard to identifying the site of greatest importance for a final diagnosis of the cause of the fever as decided by the patient's attending physician. The clinical impacts (four grades) of FDG-PET/CT and 67Ga-SPECT on the final diagnosis were evaluated. RESULTS: A total of 149 subjects were enrolled in this study between October 2014 and September 2017. No adverse events were identified among the enrolled subjects. Twenty-one subjects were excluded from the study because of deviations from the study protocol. Among the 128 remaining subjects, a final diagnosis of the disease leading to the appearance of FUO was made for 92 (71.9%) subjects. The final diagnoses in these 92 cases were classified into four groups: noninfectious inflammatory disease (52 cases); infectious disease (31 cases), malignancy (six cases); and other (three cases). These 92 subjects were eligible for inclusion in the study's analysis, but one case did not meet the PET/CT image acquisition criteria; thus, PET/CT results were analyzed for 91 cases. According to the patient-based assessments, the sensitivity of FDG-PET/CT (45%, 95% CI 33.1-58.2%) was significantly higher than that for 67Ga-SPECT (25%, 95% CI 15.5-37.5%) (P = 0.0029). The clinical impact of FDG-PET/CT (91%) was also significantly higher than that for 67Ga-SPECT (57%, P < 0.001). CONCLUSIONS: FDG-PET/CT showed a superior sensitivity to 67Ga-SPECT for the identification of the site of greatest importance for the final diagnosis of the cause of FUO.

Factors Associated With Radiation Pneumonitis in Patients Receiving Electron Boost Radiation for Breast-Conserving Therapy: A Retrospective Review.

PURPOSE: This study aimed to investigate risk factors for radiation pneumonitis (RP) caused by electron beam (EB) boost irradiation during breast-conserving therapy. METHODS AND MATERIALS: This single-institution retrospective study included patients with breast cancer treated with breast-conserving therapy from 2013 to 2019. Radiation therapy comprised whole-breast irradiation with a dose of 50 Gy and 10 Gy EB boost dose to the tumor bed. EB energies were 4, 6, 9, 12, and 15 MeV. The lung volume receiving ≥1.25 Gy (V1.25) was calculated and considered because the EB energies have a short range. All patients underwent computed tomography and positron emission tomography/computed tomography within 1 year of irradiation. Imaging evaluation was based on the Common Terminology Criteria for Adverse Events, version 5.0. RESULTS: Overall, 105 patients (median age, 62 years; range, 33-85) were included for analysis with a median follow-up period of 5 months. Average area of EB boost irradiation was 72 cm2 (range, 36-196). Grade 1 RP developed in the EB irradiation field in 22 (20.6%) patients; grade 2 RP developed in 1 (0.93%) patient. Even in patients with central lung distance (CLD) ≥1.8 cm, a positive correlation was found between RP and both energy (r = 0.36; P = .005) and V1.25 (r = 0.26; P = .04). No correlation was found between RP and irradiation field size (P = .47). The EB energy and V1.25 cutoff values were 12 MeV and 24 cm3, respectively. CONCLUSIONS: CLD of ≥1.8 cm, EB energy of ≥12 MeV, and V1.25 of ≥24 cm3 were risk factors associated with RP. Although the frequency of severe RP was not high, patients receiving high-energy electron treatment and those with a large CLD should be closely monitored.

Obesity and accumulation of subcutaneous adipose tissue are poor prognostic factors in patients with alcoholic liver cirrhosis.

In alcoholic liver cirrhosis (LC) patients, obesity has become a problem that progresses into liver dysfunction. Herein, we investigated the relationship between the prognosis of steatohepatitis and body weight, along with fat accumulation in patients with alcoholic LC. We conducted a single-center retrospective study, enrolled 104 alcoholic LC patients without hepatocellular carcinoma (HCC) based on histological and clinical evidence, and investigated factors related to poor prognosis using multivariate Cox regression and cluster analyses. Cox regression analysis revealed three independent relevant factors: subcutaneous adipose tissue (SAT) index (median 34.8 cm2/m2, P = 0.009, hazard ratio [HR] 1.017, 95% confidence interval [CI] 1.004-1.030), total bilirubin level (median 1.7 mg/dL, P = 0.003, HR 1.129, 95% CI 1.042-1.223), and prothrombin time value (median 64%, P = 0.007, HR 0.967, 95% CI 0.943-0.991). In the cluster analysis, we categorized the patients into three groups: no adipose tissue accumulation (NAT group), SAT prior accumulation (SAT group), and visceral adipose tissue prior accumulation (VAT group). The results of the three groups revealed that the SAT group displayed a significantly poor prognosis of the Kaplan-Meier curve (67.1 vs 21.2 vs 65.3, P<0.001) of a 5-year survival rate. Propensity score matching analysis of the SAT and VAT groups was performed to adjust the patient's background, but no significant differences were found between them; however, the prognosis was poorer (21.2 vs 66.3, P<0.001), and hemostatic factors were still at a lower level in the SAT group. These findings suggest that SAT accumulation type of obesity is a poor prognostic factor in alcoholic LC patients without HCC, and the hemorrhagic tendency might worsen the poor prognosis in such cases.

Safety and efficacy of Melissa officinalis extract containing rosmarinic acid in the prevention of Alzheimer's disease progression.

We conducted a randomized placebo-controlled double-blind 24-week trial using Melissa officinalis (M. officinalis) extract richly containing rosmarinic acid (RA) on patients with mild dementia due to Alzheimer's disease (AD) with the aim to examine the safety and tolerability (primary endpoint) of RA (500 mg daily) and its clinical effects and disease-related biomarker changes (secondary endpoints). Patients (n = 23) diagnosed with mild dementia due to probable AD were randomized to either the placebo or M. officinalis extract group. No differences in vital signs or physical and neurologic examination results were detected between the M. officinalis and placebo groups. No serious adverse events occurred. There were no significant differences in cognitive measures; however, the mean Neuropsychiatric Inventory Questionnaire (NPI-Q) score improved by 0.5 points in the M. officinalis group and worsened by 0.7 points in the placebo group between the baseline and 24-week visit, indicating a significant difference (P = 0.012). No significant differences were apparent in disease-related biomarkers between the groups. M. officinalis extract containing 500 mg of RA taken daily was safe and well-tolerated by patients with mild dementia due to AD. Our results suggest that RA may help prevent the worsening of AD-related neuropsychiatric symptoms.Trial registration: The registration number for this clinical trial is UMIN000007734 (16/04/2012).

Monitoring chronological change by liver-to-spleen attenuation ratio for secondary hepatic steatosis for a short term.

Parenteral nutrition-associated liver disease (PNALD) causes hepatic steatosis and moderate liver enzyme elevation due to lack of enteral nutrition and deficiency of some nutrients. However, the period for recovery from PNALD after a nutritional intervention is unknown with no report. Herein, we report a case of a 44-year-old Japanese woman with severe fatty infiltration of the liver due to malnutrition. Our nutritional support team administered appropriate total parenteral, especially fat and carnitine, nutrition to improve her malnutrition. Chronological changes in liver-to-spleen attenuation ratio were also considered because of her disease state. Computed tomography demonstrated improved attenuation of the liver, and the liver enzymes level normalized after 5 weeks from appropriate nutrition. Understanding the nutritional condition of a patient may help in elucidating an appropriate treatment strategy.

Accuracy of metabolic volume and total glycolysis among six threshold-based target segmentation algorithms.

OBJECTIVE: This study aimed to evaluate the accuracy of six threshold-based segmentation methods with different target-to-background ratios (TBR), images with different voxel sizes and image noise, in measuring metabolic volume (MV) and total glycolysis (TG). METHODS: A standard body phantom consisting of six spheres (inner diameters of 37, 28, 22, 17, 13, and 10 mm) was filled with 18F-FDG solution. The background radioactivity level was 2.65 kBq/mL, and the TBRs were 4 and 8. PET data were acquired for 30 min with list mode. PET data for 30 and 3 min were reconstructed with a three-dimensional ordered subset expectation maximization algorithm plus time-of-flight information with images with 2 and 4 mm isotropic voxels. The six methods examined were absolute standardized uptake value (SUV) of 2.5 (SUV2.5), 41%, 50%, adaptive 41%, and adaptive 50% thresholds of maximum SUV (Th41, Th50, ThA41, and ThA50, respectively); and the contrast-oriented algorithm (ThCOA). Segmented MV and TG were compared with the actual inner volume and expressed as percentages (%MVseg and %TGseg, respectively). In addition, the segmented MV was converted to the diameter, and the differences of it from the reference diameter were compared among six methods. RESULTS: The ThCOA method yielded the most accurate measurements of %MVseg and %TGseg; the difference between %MVseg or %TGseg and its reference were smaller than 10% in 30-min and 15% in 3-min images, but the segmented contour was almost the same as the reference diameter. Measurements with Th50 and ThCOA were highly accurate for both %MVseg and %TGseg in the large spheres, and the adaptive threshold methods, including ThA41, ThA50, and ThCOA, were also highly accurate in the small spheres. The voxel sizes affected the accuracy of %MVseg and %TGseg with a TBR of 4 in any threshold-based methods. CONCLUSIONS: Of the six threshold-based segmentation methods studied, ThCOA was the most accurate method for evaluating MV and TG and had only minor dependence on TBRs and sphere size. The small voxel sizes improved the variation of the accuracy in low TBR.

Rare gastric outlet obstruction owing to ectopic pancreas: a case report and literature review.

The ectopic pancreas is often observed in the gastrointestinal tract, and is typically asymptomatic. A 28-year-old woman was referred to our hospital following repeated vomiting after every meal. Following gastroscopy, contrast-enhanced computed tomography (CE-CT), and endoscopic ultrasonography (EUS), she was diagnosed with gastric outlet obstruction, also known as pyloric obstruction, caused by a giant submucosal cystic tumor. The condition was successfully treated with EUS-guided cystic drainage, and she was diagnosed with a cystic tumor originating from the ectopic pancreas. The tumor shrank following EUS-guided cystic drainage, and her obstructive symptoms resolved. In cases with overgrowth of the ectopic pancreas, the differential diagnosis of malignancy is important but challenging. Herein, we report a unique final pathology of this rare case and discuss the findings with a literature review.

Small Intestinal Bacterial Overgrowth Diagnosed by a Breath Test and Improved by Rifaximin in a Patient with Hepatic Encephalopathy and Alcoholic Liver Cirrhosis.

A 66-year-old Japanese man was admitted to our hospital with grade 2 hepatic encephalopathy (HE). Abdominal computed tomography and laboratory examinations revealed decompensated liver cirrhosis. Intravenous administration of branched-chain amino acids immediately ameliorated the HE, and lactulose was initiated. However, a breath test revealed small intestinal bacterial overgrowth (SIBO); therefore, rifaximin was additionally initiated. The breath test was repeated after discharge, when no evidence of SIBO or overt HE was identified. This case suggested that a breath test is effective for the identification of SIBO and that the administration of a poorly absorbed antibiotic should be considered in SIBO-positive HE patients taking lactulose.

[The 41st Report on Survey of the Adverse Reaction to Radiopharmaceuticals (The 44th Survey in 2018)].

This survey was performed in order to investigate the incidence of adverse reactions to radiopharmaceuticals in FY2018 in Japan. It was based on the responses to questionnaires sent to nuclear medicine institutions. Replies were obtained from 999 institutions among 1,230 to which the questionnaire had been sent. Fourteen cases of adverse reactions were reported. A total of 1,017,702 radiopharmaceutical administrations were reported. The incidence of adverse reactions per 100,000 cases was 1.4. No case of deficient products was reported.

Superior mediastinal lymphadenopathy by silicosis mimicking metastasis of papillary thyroid carcinoma - Case report and literature review.

Silicosis is caused by inhalation of silica dust and is the most common type of pneumoconiosis. The characteristics of silicosis are inflammation of lung tissue and calcified lymphadenopathy of pulmonary hilum, mediastinum and paratrachea. We present a papillary thyroid carcinoma (PTC) case with paratracheal and superior mediastinal calcified lymphadenopathy caused by silicosis. The patient did not exhibit any respiratory symptoms or abnormal chest x-ray findings due to early phase silicosis. The lymph nodes were thought to be metastasis of PTC before surgery. Patient underwent total thyroidectomy with neck and superior mediastinum dissection. Post-surgery pathological examination exhibited coexistence of silica nodules and micrometastasis of PTC in paratracheal lymph nodes, but only silica nodules were observed in superior mediastinum lymph nodes. Patient's occupation was office worker but had worked as a stonemason for several decades prior. This is a first observed case of superior mediastinal lymphadenopathy by silicosis mimicking metastasis of PTC. Benign calcified lymphadenopathy may mimic metastasis of PTC in the evaluation of neck or mediastinal lesions.

Full report on a survey of adverse reactions to radiopharmaceuticals from 1975 to 2017 in Japan.

OBJECTIVE: This pharmacovigilance-based survey was aimed at determining the prevalence of, and association between, radiopharmaceuticals and adverse reactions to radiopharmaceuticals from 1975 to 2017 in Japan. METHODS: The Subcommittee for Safety Issues of Radiopharmaceuticals of the Japan Radioisotope Association's Medical Science and Pharmaceutical Committee mailed a form for reporting adverse reactions to radiopharmaceuticals to all institutes performing nuclear medicine examinations in Japan. This investigation included adverse reactions to diagnostic radiopharmaceuticals labeled with both single-photon- and positron-emitting radionuclides and therapeutic sodium iodide labeled with 131I. Each institute returned the reporting form to the subcommittee each time an adverse reaction occurred. RESULTS: Replies were obtained from 75% of the institutions. In total, 1099 adverse reactions were reported from 46,645,580 radiopharmaceutical administrations, giving a prevalence of 2.4 adverse reactions per 100,000 administrations (95% confidence interval 2.2-2.5). Adverse reactions were most frequently observed for 131I-iodomethylnorcholesterol (230.1/105 administrations), followed by 131I-HSA (76.3/105 administrations), 131I-sodium iodohippurate (31.2/105 administrations), and 99mTc-DTPA (12.0/105 administrations). Comparison of adverse reactions between before and after 1997 revealed that prevalence dropped from 3.7/105 administrations (95% confidence interval 3.5-4.1) to 1.5/105 administrations (95% confidence interval 1.4-1.6). During the study period, vasovagal reactions accounted for 50.3% of adverse reactions, fever for 7.5%, allergic reactions for 25.7%, and other for 16.5%; 3.7% of all adverse reactions were considered severe but none were lethal. A definite, probable, possible, less likely, and uncertain causal relationship with radiopharmaceuticals was observed in 13.1%, 33.7%, 39.9%, 6.2%, and 7.1% of adverse reactions, respectively. CONCLUSIONS: These results suggest that nuclear medicine staff must be aware of the possibility of adverse reactions from radiopharmaceuticals, despite their rarity.

Diagnostic accuracy of an artificial neural network compared with statistical quantitation of myocardial perfusion images: a Japanese multicenter study.

PURPOSE: Artificial neural networks (ANN) might help to diagnose coronary artery disease. This study aimed to determine whether the diagnostic accuracy of an ANN-based diagnostic system and conventional quantitation are comparable. METHODS: The ANN was trained to classify potentially abnormal areas as true or false based on the nuclear cardiology expert interpretation of 1001 gated stress/rest 99mTc-MIBI images at 12 hospitals. The diagnostic accuracy of the ANN was compared with 364 expert interpretations that served as the gold standard of abnormality for the validation study. Conventional summed stress/rest/difference scores (SSS/SRS/SDS) were calculated and compared with receiver operating characteristics (ROC) analysis. RESULTS: The ANN generated a better area under the ROC curves (AUC) than SSS (0.92 vs. 0.82, p < 0.0001), indicating better identification of stress defects. The ANN also generated a better AUC than SDS (0.90 vs. 0.75, p < 0.0001) for stress-induced ischemia. The AUC for patients with old myocardial infarction based on rest defects was 0.97 (0.91 for SRS, p = 0.0061), and that for patients with and without a history of revascularization based on stress defects was 0.94 and 0.90 (p = 0.0055 and p < 0.0001 vs. SSS, respectively). The SSS/SRS/SDS steeply increased when ANN values (probability of abnormality) were >0.80. CONCLUSION: The ANN was diagnostically accurate in various clinical settings, including that of patients with previous myocardial infarction and coronary revascularization. The ANN could help to diagnose coronary artery disease.