Correlation of Preoperative Imaging Findings and Parathyroidectomy Outcomes Support NICE 2019 Guidance.

CONTEXT: Preoperative localization studies are standard practice in patients undergoing parathyroidectomy for primary hyperparathyroidism (pHPT). The most common modalities are neck ultrasound (US) and sestamibi scanning. However, the nature of pHPT is changing, with imaging increasingly yielding negative results. Numerous studies suggest unlocalized disease is associated with poor outcomes, calling into question whether such patients are best treated conservatively. OBJECTIVE: This study aims to correlate parathyroidectomy outcomes with preoperative imaging in a single, high-volume institution. METHODS: Data from a prospectively maintained departmental database of operations performed from 2017 to 2019 were analyzed. All patients undergoing first-time surgery for sporadic pHPT were included. Data collected included patient demographics, preoperative imaging, surgical strategy, and postoperative outcomes. RESULTS: A total of 609 consecutive parathyroidectomies were included, with a median age of 59 years (range 20-87 years). The all-comer cure rate was 97.5%; this was 97.9% in dual localized patients (those with positive US and sestamibi), compared to 95.8% in the dual unlocalized group (those with negative US and sestamibi) (P = 0.33). Unilateral neck exploration was the chosen approach in 59.9% of patients with double-positive imaging and 5.7% of patients with double-negative imaging (otherwise, bilateral parathyroid visualization was performed). There was no significant difference in postoperative complications between patients undergoing unilateral or bilateral neck exploration. CONCLUSIONS: Patients with negative preoperative imaging who undergo parathyroidectomy are cured in almost 96% of cases, compared to 98% when the disease is localized. This difference does not reach statistical or clinical significance. These findings therefore support current recommendations that all patients with pHPT who are likely to benefit from operative intervention should be considered for parathyroidectomy, irrespective of preoperative imaging findings.

Comparing the Prognostic Value of Stress Myocardial Perfusion Imaging by Conventional and Cadmium-Zinc Telluride Single-Photon Emission Computed Tomography through a Machine Learning Approach.

We compared the prognostic value of myocardial perfusion imaging (MPI) by conventional- (C-) single-photon emission computed tomography (SPECT) and cadmium-zinc-telluride- (CZT-) SPECT in a cohort of patients with suspected or known coronary artery disease (CAD) using machine learning (ML) algorithms. A total of 453 consecutive patients underwent stress MPI by both C-SPECT and CZT-SPECT. The outcome was a composite end point of all-cause death, cardiac death, nonfatal myocardial infarction, or coronary revascularization procedures whichever occurred first. ML analysis performed through the implementation of random forest (RF) and k-nearest neighbors (KNN) algorithms proved that CZT-SPECT has greater accuracy than C-SPECT in detecting CAD. For both algorithms, the sensitivity of CZT-SPECT (96% for RF and 60% for KNN) was greater than that of C-SPECT (88% for RF and 53% for KNN). A preliminary univariate analysis was performed through Mann-Whitney tests separately on the features of each camera in order to understand which ones could distinguish patients who will experience an adverse event from those who will not. Then, a machine learning analysis was performed by using Matlab (v. 2019b). Tree, KNN, support vector machine (SVM), Naïve Bayes, and RF were implemented twice: first, the analysis was performed on the as-is dataset; then, since the dataset was imbalanced (patients experiencing an adverse event were lower than the others), the analysis was performed again after balancing the classes through the Synthetic Minority Oversampling Technique. According to KNN and SVM with and without balancing the classes, the accuracy (p value = 0.02 and p value = 0.01) and recall (p value = 0.001 and p value = 0.03) of the CZT-SPECT were greater than those obtained by C-SPECT in a statistically significant way. ML approach showed that although the prognostic value of stress MPI by C-SPECT and CZT-SPECT is comparable, CZT-SPECT seems to have higher accuracy and recall.

Increased heterogeneity of brain perfusion predicts the development of cerebrovascular accidents.

ABSTRACT: The heterogeneity of brain perfusion is related to the risk factors of thromboembolic events such as antiphospholipid syndrome. However, the effectiveness of brain perfusion heterogeneity as a marker to predict thromboembolic events has not been confirmed. Our objective was to evaluate the effectiveness of brain perfusion heterogeneity as a marker to predict the development of cerebrovascular accidents. In this retrospective cohort study, patients who underwent Tc-99m ECD brain SPECT from January 1, 2006 through December 31, 2008 were included. Each study was reoriented with the Talairach space provided by the NeuroGam Software package. Heterogeneity of brain perfusion was measured as the coefficient of variation. The study outcome was the risk of cerebral vascular accidents in patients with increased heterogeneity of brain perfusion between January 1, 2006 and December 31, 2015. A multiple Cox proportional hazards model was applied to evaluate the risk of cerebrovascular accidents. A total of 70 patients were included in this study. The median age was 39 years (range, 28 - 59 years). There were 55 (78.6%) women. For increased heterogeneity of brain perfusion, the hazard ratio of cerebrovascular accidents was 2.68 (95% CI, 1.41 - 5.09; P = .003) after adjusting for age, sex, hypertension, diabetes mellitus, and dyslipidemia. Our study suggests that increased heterogeneity of brain perfusion is associated with an increased risk of cerebrovascular accidents.

Effects of the COVID-19 pandemic on myocardial perfusion imaging for ischemic heart disease.

PURPOSE: We assessed the effects of the COVID-19 pandemic on myocardial perfusion imaging (MPI) for ischemic heart disease during the lockdown imposed by the Italian Government. METHODS: We retrospectively reviewed the number and the findings of stress single-photon emission computed tomography (SPECT)-MPI performed between February and May 2020 during the COVID-19 pandemic at the University of Napoli Federico II. The number and the findings of stress SPECT-MPI studies acquired in the corresponding months of the years 2017, 2018, and 2019 were also evaluated for direct comparison. RESULTS: The number of stress SPECT-MPI studies performed during the COVID-19 pandemic (n = 123) was significantly lower (P < 0.0001) compared with the mean yearly number of procedures performed in the corresponding months of the years 2017, 2018, and 2019 (n = 413). Yet, the percentage of abnormal stress SPECT-MPI studies was similar (P = 0.65) during the pandemic (36%) compared with the mean percentage value of the corresponding period of the years 2017, 2018, and 2019 (34%). CONCLUSION: The number of stress SPECT-MPI studies was significantly reduced during the COVID-19 pandemic compared with the corresponding months of the previous 3 years. The lack of difference in the prevalence of abnormal SPECT-MPI studies between the two study periods strongly suggests that many patients with potentially abnormal imaging test have been missed during the pandemic.

Coronary Computed Tomography Angiography Compared With Single Photon Emission Computed Tomography Myocardial Perfusion Imaging as a Guide to Optimal Medical Therapy in Patients Presenting With Stable Angina: The RESCUE Trial.

Background The RESCUE (Randomized Evaluation of Patients with Stable Angina Comparing Utilization of Noninvasive Examinations) trial was a randomized, controlled, multicenter, comparative efficacy outcomes trial designed to assess whether initial testing with coronary computed tomographic angiography (CCTA) is noninferior to single photon emission computed tomography (SPECT) myocardial perfusion imaging in directing patients with stable angina to optimal medical therapy alone or optimal medical therapy with revascularization. Methods and Results The end point was first major adverse cardiovascular event (MACE) (cardiac death or myocardial infarction), or revascularization. Noninferiority margin for CCTA was set a priori as a hazard ratio (HR) of 1.3 (95% CI=0, 1.605). One thousand fifty participants from 44 sites were randomized to CCTA (n=518) or SPECT (n=532). Mean follow-up time was 16.2 (SD 7.9) months. There were no cardiac-related deaths. In patients with a negative CCTA there was 1 acute myocardial infarction; in patients with a negative SPECT examination there were 2 acute myocardial infarctions; and for positive CCTA and SPECT, 1 acute myocardial infarction each. Participants in the CCTA arm had a similar rate of MACE or revascularization compared with those in the SPECT myocardial perfusion imaging arm, (HR, 1.03; 95% CI=0.61-1.75) (P=0.19). CCTA segment involvement by a stenosis of ≥50% diameter was a better predictor of MACE and revascularization at 1 year (P=0.02) than the percent reversible defect size by SPECT myocardial perfusion imaging. Four (1.2%) patients with negative CCTA compared with 14 (3.2%) with negative SPECT had MACE or revascularization (P=0.03). Conclusions There was no difference in outcomes of patients who had stable angina and who underwent CCTA in comparison to SPECT as the first imaging test directing them to optimal medical therapy alone or with revascularization. CCTA was a better predictor of MACE and revascularization. Registration Information URL: https://www.clinicaltrials.gov/. Identifier: NCT01262625.

A Review of Multimodal Medical Image Fusion Techniques.

The medical image fusion is the process of coalescing multiple images from multiple imaging modalities to obtain a fused image with a large amount of information for increasing the clinical applicability of medical images. In this paper, we attempt to give an overview of multimodal medical image fusion methods, putting emphasis on the most recent advances in the domain based on (1) the current fusion methods, including based on deep learning, (2) imaging modalities of medical image fusion, and (3) performance analysis of medical image fusion on mainly data set. Finally, the conclusion of this paper is that the current multimodal medical image fusion research results are more significant and the development trend is on the rise but with many challenges in the research field.

Research of Multimodal Medical Image Fusion Based on Parameter-Adaptive Pulse-Coupled Neural Network and Convolutional Sparse Representation.

Visual effects of medical image have a great impact on clinical assistant diagnosis. At present, medical image fusion has become a powerful means of clinical application. The traditional medical image fusion methods have the problem of poor fusion results due to the loss of detailed feature information during fusion. To deal with it, this paper proposes a new multimodal medical image fusion method based on the imaging characteristics of medical images. In the proposed method, the non-subsampled shearlet transform (NSST) decomposition is first performed on the source images to obtain high-frequency and low-frequency coefficients. The high-frequency coefficients are fused by a parameter-adaptive pulse-coupled neural network (PAPCNN) model. The method is based on parameter adaptive and optimized connection strength ß adopted to promote the performance. The low-frequency coefficients are merged by the convolutional sparse representation (CSR) model. The experimental results show that the proposed method solves the problems of difficult parameter setting and poor detail preservation of sparse representation during image fusion in traditional PCNN algorithms, and it has significant advantages in visual effect and objective indices compared with the existing mainstream fusion algorithms.

Novel Findings on SPECT-CT Tc-99 Sestamibi Imaging for Primary Hyperparathyroidism.

BACKGROUND: The addition of SPECT-CT to Tc-99 sestamibi has become a valuable tool for parathyroid localization in primary hyperparathyroidism (PHP). However, the enhanced sensitivity of this test can lead to unexpected and significant findings. We sought to identify the frequency and types of nonparathyroid detections by SPECT-CT. MATERIALS AND METHODS: With institutional approval, we reviewed all SPECT-CT studies performed for PHP between October 2012 and August 2018 for incidental nonparathyroid abnormalities. The electronic medical record was referenced to determine the type of lesion confirmed by additional evaluation. RESULTS: Among 2413 studies, 652 patients (27%) had 677 (28%) nonparathyroid findings. The most common were thyroid nodules (331/677, 49%), including 47 (6.9%) malignancies to date: 40 papillary thyroid cancers (11 microcarcinomas), five follicular thyroid cancers, one medullary carcinoma, and one noninvasive follicular thyroid neoplasm with papillary-like features. One hundred and seventy-seven patients had pulmonary nodules (26%), of whom nine were diagnosed with primary lung lesions (6 non-small-cell cancers, one small-cell cancer, one carcinoid, and one pulmonary sequestration). SPECT-CT revealed 14 patients (2.1%) with breast abnormalities, including three cancers. Nine patients (1.3%) demonstrated metastatic diseases within the lungs (4), bones (3), and mediastinum (2). One patient was diagnosed with follicular lymphoma. Two intracranial tumors were also identified, as well as dysplastic Barrett's esophagitis (1), hiatal hernia (20, 3%), and aortic aneurysm (13, 1.8%). In all, 72/677 (10.6%) PHP patients exhibited premalignant or malignant nonparathyroid SPECT-CT findings. CONCLUSIONS: In patients undergoing localization for PHP with Tc-99 sestamibi SPECT-CT, nonparathyroid findings are frequent (27%) and can lead to newly diagnosed malignant or premalignant lesions in at least 3% of patients to date.

Myocardial Ischemic Burden and Differences in Prognosis Among Patients With and Without Diabetes: Results From the Multicenter International REFINE SPECT Registry.

OBJECTIVE: Prevalence and prognostic impact of cardiovascular disease differ between patients with or without diabetes. We aimed to explore differences in the prevalence and prognosis of myocardial ischemia by automated quantification of total perfusion deficit (TPD) among patients with and without diabetes. RESEARCH DESIGN AND METHODS: Of 20,418 individuals who underwent single-photon emission computed tomography myocardial perfusion imaging, 2,951 patients with diabetes were matched to 2,951 patients without diabetes based on risk factors using propensity score. TPD was categorized as TPD = 0%, 0% < TPD < 1%, 1% ≤ TPD < 5%, 5% ≤ TPD ≤ 10%, and TPD >10%. Major adverse cardiovascular events (MACE) were defined as a composite of all-cause mortality, myocardial infarction, unstable angina, or late revascularization. RESULTS: MACE risk was increased in patients with diabetes compared with patients without diabetes at each level of TPD above 0 (P < 0.001 for interaction). In patients with TPD >10%, patients with diabetes had greater than twice the MACE risk compared with patients without diabetes (annualized MACE rate 9.4 [95% CI 6.7-11.6] and 3.9 [95% CI 2.8-5.6], respectively, P < 0.001). Patients with diabetes with even very minimal TPD (0% < TPD < 1%) experienced a higher risk for MACE than those with 0% TPD (hazard ratio 2.05 [95% CI 1.21-3.47], P = 0.007). Patients with diabetes with a TPD of 0.5% had a similar MACE risk as patients without diabetes with a TPD of 8%. CONCLUSIONS: For every level of TPD >0%, even a very minimal deficit of 0% < TPD < 1%, the MACE risk was higher in the patients with diabetes compared with patients without diabetes. Patients with diabetes with minimal ischemia had comparable MACE risk as patients without diabetes with significant ischemia.

Myocardial Perfusion SPECT 2018 in Germany: Results of the 8th Survey.

AIM: This paper presents the results of the 8th survey of myocardial perfusion SPECT (MPS) from the reporting year 2018. METHODS: 291 questionnaires (184 practices (PR), 77 hospitals (HO), 30 university hospitals (UH)) were evaluated. Results of the last survey from 2015 are set in squared brackets. RESULTS: MPS of 145 930 [121 939] patients were reported (+ 19.6 %). 76 % [78 %] of all patients were studied in PR, 16 % [14 %] in HO, and 8 % [8 %] in UH, mostly with a 2-day-protocol 48 % [50 %]. 99.96 % [98 %] of all MPS were performed with Tc-99 m radiopharmaceuticals and in 0.04 % with Tl-201.A pharmacological stress test was applied in 49 % [43 %] (23 % [22 %] adenosine, 26 % [20 %] regadenoson, dipyridamole or dobutamine together < 1 % [1 %]). Attenuation correction was performed in 26 % [25 %] of all MPS, gated SPECT in 86 % [80 %] of stress MPS, in 87 % [78 %] of rest and in 83 % [76 %] of all stress and rest MPS. 67 % [53 %] of the departments performed MPS scoring by default, whereas 16 % [24 %] did not apply this feature at all.69 % [60 %] reported an increase or no changes in their MPS patient numbers. One hundred twenty-six departments which participated in the surveys from 2009 to 2018 reported an increase in MPS by 44 %. 69 % [70 %] of the MPS were requested by ambulatory care cardiologists. CONCLUSION: The 2018 MPS survey reveals a high-grade adherence of routine MPS practice to current guidelines. The positive development in MPS performance and MPS numbers observed since 2012 remains ongoing.

Trends in High- and Low-Value Cardiovascular Diagnostic Testing in Fee-for-Service Medicare, 2000-2016.

Importance: Owing to a rapid increase in rates of diagnostic cardiovascular testing in the 1990s and early 2000s, the Centers for Medicare & Medicaid Services implemented a series of payment changes intended to reduce overall spending on fee-for-service testing. Whether guideline-concordant testing has been subsequently affected is unknown to date. Objective: To determine whether changes in overall rates of use of diagnostic cardiovascular tests were associated with changes in high-value testing recommended by guidelines and low-value testing that is expected to provide minimal benefits. Design, Setting, and Participants: This retrospective cohort study assessed a national 5% random sample of Medicare fee-for-service beneficiaries aged 65 to 95 years from January 1, 1999, through December 31, 2016. Data were analyzed from February 15, 2018, through August 15, 2019. Exposures: Eligibility to receive high-value testing (assessment of left ventricular systolic function among patients hospitalized with acute myocardial infarction or heart failure) and low-value testing (stress testing before low-risk noncardiac surgery and routine stress testing within 2 years of coronary revascularization not associated with acute care visits). Main Outcomes and Measures: Age- and sex-adjusted annual rates of overall, high-value, and low-value diagnostic cardiovascular testing. Results: Mean (SD) age was similar over time (75.57 [7.32] years in 2000-2003; 74.82 [7.79] years in 2012-2016); the proportion of women slightly declined over time (63.23% in 2000 to 2003; 57.27% in 2012 to 2016). The rate of overall diagnostic cardiovascular testing per 1000 patient-years among the 5% sample of Medicare beneficiaries increased from 275 in 2000 to 359 in 2008 (P < .001) and then declined to 316 in 2016 (P < .001). High-value testing increased steadily over the entire study period for patients with acute myocardial infarction (85.7% to 89.5%; P < .001) and heart failure (72.6% to 80.1%; P < .001). Low-value testing among patients undergoing low-risk surgery increased from 2.4% in 2000 to 3.8% in 2008 (P < .001) but then declined to 2.5% in 2016 (P < .001). Low-value testing within 2 years of coronary revascularization slightly increased from 47.4% in 2000 to 49.2% in 2003 (P = .03) but then declined to 30.8% in 2014 (P < .001). Conclusions and Relevance: Rates of overall and low-value diagnostic cardiovascular testing appear to have declined considerably and rates of high-value testing have increased slightly. Payment changes intended to reduce spending on overall testing may not have adversely affected testing recommended by guidelines.

Quantitative SPECT: a survey of current practice in the UK Nuclear Medicine Community.

OBJECTIVES: Nuclear Medicine is a quantitative imaging modality. However, until recently, quantitative single photon emission computed tomography (SPECT) has been limited to ratios or comparisons to databases, or indeed volume measurements, and therefore has not truly quantified uptake in areas of interest. Following the growth of dosimetry associated with nuclear medicine therapies, tools to perform quantitative SPECT in terms of kBq/cc or standardised uptake value (SUV) have become more readily available, although its use does not appear to be widespread. The aim of this study was to get a snapshot of quantitative SPECT use, and to determine where the future of this technology may lie. METHODS: The data for this survey were collected through a web-based form made available at a national quantitative SPECT meeting, and later distributed to the UK nuclear medicine community. A series of questions looking at current practice, technique and future thoughts were presented to respondents in the form of multiple-choice questions where single and multiple selections could be made. RESULTS: The responses showed significant use of quantitative SPECT for established techniques, in alignment with the prevalence of the relevant imaging studies. There was a significant minority of respondents performing kBq/cc and SUV SPECT, and SPECT for radionuclide therapy dosimetry. Technique for quantitative SPECT varied significantly typically but nevertheless the predicted future for quantitative SPECT was positive: particularly for kBq/cc and SUV SPECT. Impediments to the success of the technology were mostly around software availability and uncertainties around usefulness. CONCLUSION: The results of this survey suggest that the future of truly quantitative SPECT looks promising.

Comparison of automated quantification and semiquantitative visual analysis findings of IQ SPECT MPI with conventional coronary angiography in patients with stable angina.

OBJECTIVE: The aim of this study was to assess the validity of automated quantitative and semiquantitative visual analysis of total perfusion deficit (TPD) using the IQ SPECT gamma camera system compared to conventional coronary angiographically detected significant coronary artery disease (CAD). METHODS: The study included patients with suspected CAD who underwent myocardial perfusion single photon emission computed tomography and conventional coronary angiography. The summed stress score (SSS), summed rest score (SRS), and summed difference score (SDS) (semiquantitative visual analysis results) were assessed using a 5-point scale in a standard 17-segment model, and TPD (stress, rest, and ischemic TPD) was quantified using automated software. RESULTS: In all, 84 patients (Group 1, those who underwent revascularization) had significant coronary artery lesions, and 81 (Group 2) had non-significant lesions. The median interquartile range values were: stress-TPD (sTPD): 16 (3.5- 33.5) vs 9.2 (2-17.9), rest-TPD: 9.4 (2.2-18.8) vs 4 (1-11), and 6.9 (1.9-14.1) vs 3.4 (1-6.1) for ischemic-TPD (iTPD) in Group 1 and Group 2, respectively. To detect ischemia, the optimal cut-off points were 9.5 (sensitivity: 75%, specificity; 60%) for sTPD, and 4.5 (sensitivity: 56%, specificity: 73%) for iTPD. There were significant correlations between quantitative and semi-quantitative methods in detection of significant coronary artery disease (sTPD-SSS: r=0.954, sTPD-SDS: r=0.746, iTPD-SSS: r=0.654, iTPD-SDS: r=0.759; p<0.05 for all). CONCLUSION: The quantitative analysis and summed stress scores produced by the IQ SPECT system appear to be a useful and valid method to detect significant CAD.

From the Reading Room to the Courtroom-The Use of Molecular Radionuclide Imaging in Criminal Trials.

Recent years have witnessed an expanded use of single-photon emission CT and PET for a wide range of clinical applications, including imaging of brain abnormalities. As a result, molecular brain imaging is now being more extensively utilized in criminal cases, in particular in the sentencing phase of a trial. This perspective aims to provide a brief overview for the practicing radiologist of this expanded use of single-photon emission CT and PET in criminal cases and will discuss the role of radiology in this field.

Use of cardiac magnetic resonance imaging and single photon emission computed tomography for the diagnosis of stable coronary artery disease in Switzerland.

BACKGROUND: Direct invasive testing in the diagnosis of stable coronary artery disease (CAD) involves high costs and relevant risks. By comparison, single-photon emission computed tomography (SPECT) and cardiac magnetic resonance imaging (CMR) are noninvasive diagnostic tests. SPECT is currently the most widely used diagnostic technique, but new medical and economic evidence favours CMR. Guidelines do not recommend one technique in preference to the other, and their use in Switzerland is poorly documented, as a scoping study by the Swiss Medical Board reported. We aimed at a quantitative and qualitative analysis of the use of these diagnostic techniques in Swiss hospitals. METHODS: We contacted nine Swiss hospitals to obtain the number of SPECT/CMR investigations used to diagnose stable CAD in 2014–2016 and submitted a questionnaire to investigate the advantages and limitations of the two imaging techniques. In addition, two experts in SPECT and CMR, respectively, at two university hospitals were interviewed, using open questions. RESULTS: Data were obtained from 8 hospitals, and 22 questionnaires were returned. In Switzerland, both techniques have been implemented very differently in different hospitals, but the overall number of diagnostic procedures has increased. The questionnaires reported lower scores for CMR regarding the availability of the scans, contraindications and the suitability of the technique for the diagnosis of CAD. The experts described potential conflicts of interest in some institutions, depending on how the cardiology and radiology departments collaborated, and highlighted the debated results of studies comparing CMR with SPECT for the diagnosis of CAD. The main conclusion drawn from the interviews was the recommendation of a patient-centred evaluation. CONCLUSION: The use of SPECT versus CMR in Switzerland for the diagnosis of stable CAD is heterogeneous, but reflects the guidelines, which do not distinguish between the two diagnostic techniques. Expert opinions underlined that discussion should not be so much about the choice of the diagnostic modality but about how a clinical question in a patient can best be answered.

Utilidad de la 18f-colina pet/tc en hiperparatiroidismo primario persistente o recurrente: experiencia inicial / Usefulness of 18f-choline pet / tc in persistent or recurrent primary hyperparathyroidism: initial experience

El hiperparatiroidismo persistente/recurrente representa un desafío en la localización del tejido paratiroideo hiperfuncionante. En esta subpoblación, los métodos convencionales ofrecen un menor rédito diagnóstico. La 18F-colina PET/TC podría ser una buena alternativa dada su mejor resolución espacial, capacidad de detectar glándulas ectópicas y la conjunción de la imagen molecular y anatómica. Sin embargo, la evidencia en este subgrupo de pacientes es escasa. Objetivo: evaluar la utilidad de la 18F-colina PET/TC como método de localización en el hiperparatiroidismo persistente o recurrente. Materiales y métodos: se analizaron los pacientes con 18F-colina PET/TC para hiperparatiroidismo entre diciembre de 2015 y enero de 2018 en un centro terciario de alto volumen. Se analizaron el número de lesiones, su localización, tamaño y el Standard Uptake Value máximo (SUV max) en las imágenes tempranas y tardías. Se compararon los resultados con los métodos convencionales. Resultados: 7 de 15 pacientes habían sido operados previamente (persistentes/recurrentes). La 18F-colina PET/TC detectó 6/7 casos (83,33%), la ecografía cervical 1/4 (25%) y el SPECT de paratiroides y la resonancia nuclear magnética 2/5 (40%). El SUV max obtenido fue variable, en la mitad de los casos a los 10 minutos y en los restantes a la hora; el tamaño promedio de las lesiones fue 8,61 mm (6-12 mm). Conclusiones: la 18F-colina PET/TC muestra una alta tasa de detección en los pacientes con hiperparatiroidismo persistente/recurrente. La combinación del comportamiento biológico del PET con los hallazgos morfológicos aportados por la TC con contraste endovenoso le ofrecería ventajas sobre otros estudios que podrían posicionarlo como método de primera línea en esta subpoblación. (AU)

Persistent or recurrent hyperparathyroidism represents a challenge regarding the localization of the hyper-functioning parathyroid tissue. In this subpopulation of hyperpharathyroid patients, conventional methods have a low diagnostic yield. The 18F-choline PET /CT could be a good alternative given its better spatial resolution, ability to detect ectopic glands, and the conjunction of the molecular and anatomical image. However, the evidence in this subgroup of patients is limited. Objective: to evaluate the utility of 18F-choline PET/ CT as a localization method in persistent or recurrent hyperparathyroidism. Materials and methods: patients with 18F-choline PET / CT for hyperparathyroidism between December 2015 and January 2018 in a high-volume tertiary center were included. The number of lesions, and their location, size, and maximum Standard Uptake Value (SUV) in the early and late images were analyzed. The results were compared to conventional methods. Results: 7 of 15 patients had been previously operated (persistent/recurrent). 18F-choline PET / CT detected 6/7 cases (83,33%), cervical ultrasound 1/4 (25%) and parathyroid SPECT and magnetic resonance 2/5 (40%). The maximum SUV was variable, one half at 10 minutes and the other half at 60 minutes; the average size of the lesions was 8.61 mm (6-12 mm). Conclusions: 18F-Choline PET / CT shows a high detection rate in patients with persistent / recurrent hyperparathyroidism. The combination of the biological behavior of PET with the morphological findings provided by CT with intravenous contrast would offer advantages over other studies that could position it as a first line method in this subpopulation. (AU)

A New Relational Database Including Clinical Data and Myocardial Perfusion Imaging Findings in Coronary Artery Disease.

BACKGROUND: The aim of this study was to test a relational database including clinical data and imaging findings in a large cohort of subjects with suspected or known Coronary Artery Disease (CAD) undergoing stress single-photon emission computed tomography (SPECT) myocardial perfusion imaging. METHODS: We developed a relational database including clinical and imaging data of 7995 subjects with suspected or known CAD. The software system was implemented by PostgreSQL 9.2, an open source object-relational database, and managed from remote by pgAdmin III. Data were arranged according to a logic of aggregation and stored in a schema with twelve tables. Statistical software was connected to the database directly downloading data from server to local personal computer. RESULTS: There was no problem or anomaly for database implementation and user connections to the database. The epidemiological analysis performed on data stored in the database demonstrated abnormal SPECT findings in 46% of male subjects and 19% of female subjects. Imaging findings suggest that the use of SPECT imaging in our laboratory is appropriate. CONCLUSION: The development of a relational database provides a free software tool for the storage and management of data in line with the current standard.

Estudo da permeabilidade vascular pulmonar e das junções interendoteliais na malária experimental / Study of pulmonary vascular permeability and interendothelial junctions in experimental malaria

Infecções por Plasmodium spp. podem acarretar em complicações pulmonares (1 a 40% dos casos), que podem resultar no desenvolvimento da síndrome do desconforto respiratório agudo (SDRA). Esta síndrome é caracterizada por inflamação aguda, lesão do endotélio alveolar e do parênquima pulmonar, disfunção e aumento da permeabilidade da barreira alvéolo-capilar pulmonar e, consequente, formação de efusão pleural. Neste sentido, os mecanismos de regulação da permeabilidade das células endoteliais e as junções interendoteliais têm papel crítico na manutenção do endotélio pulmonar. O objetivo do estudo foi determinar precocemente o desenvolvimento da SDRA associada à malária por tomografia computadorizada por emissão de fóton único (SPECT/CT), além de identificar alterações nas junções interendoteliais das células endoteliais pulmonares primárias de camundongos DBA/2 (CEPP-DBA/2), após contato com os eritrócitos parasitados de Plasmodium berghei ANKA (EP-PbA). Os nossos resultados demonstraram que é possível identificar alterações na aeração pulmonar no 5° e 7° dia após a infecção e, consequentemente, diferenciar os animais que desenvolveriam SDRA daqueles que evoluiriam para hiperparasitemia (HP). Além disso, observamos em CEPP-DBA/2 que o contato direto com EP-PbA aumenta da abertura das junções interendoteliais e da permeabilidade vascular. Assim, avaliamos a diminuição da expressão das proteínas das junções interendoteliais que contribuem para o aumento da permeabilidade vascular, por imunofluorescência e Western Blot. Apesar da SDRA ter sido identificada há mais de 50 anos, ainda não se conhece formas de diagnóstico precoce e os mecanimos efetivos de desenvolvimento desta enfermidade, que permitam um tratamento efetivo e que evite a morte do paciente. Portanto, sugere-se que a técnica de SPECT/CT seja uma importante ferramenta de diagnóstico para identificação precoce de SDRA associado a malária

Infections by Plasmodium spp. can lead to pulmonary complications (1 to 40% of the cases), that can result in the development of acute respiratory distress syndrome (ARDS). This syndrome is characterized by the acute inflammation, injury of the alveolar endothelium and pulmonary parenchyma, dysfunction and increased permeability of the pulmonary alveolar-capillary barrier and, consequently, formation of pleural effusion. In this aspect, mechanisms of regulation of endothelial cell permeability and interendothelial junctions play a critical role in the maintenance of the pulmonary endothelium. The present study aimed to determine the early development of single-photon emission computed tomography (SPECT/CT) associated malaria ARDS in addition to identifying changes in the interendothelial junctions of the primary pulmonary endothelial cells of DBA/2 mice (CEPP-DBA/2) after contact with erythrocytes infected with Plasmodium berghei ANKA (EP-PbA). Our results demonstrated that is possible to identify changes in lung aeration on the 5th and 7th day after infection and, consequently, differentiate the animals that should develop ARDS from those that would evolve to hyperparasitemia (HP). In addition, we observed in CEPP-DBA/2 that direct contact with EP-PbA increases the opening of the interendothelial junctions and vascular permeability. Thus, we evaluated that decrease the expression of interendothelial junction proteins contribute to the increase of vascular permeability, by immunofluorescence and Western Blot. Although ARDS was identified more than 50 years ago, it is not yet known what forms of early diagnosis, and the effective mechanisms of development of this disease, that allow an effective treatment and that prevent the death of the patient. Therefore, it is suggested that the SPECT/CT technique is a valuable tool to promote the early identification of ARDS associated with malaria

A Monte Carlo study on the performance evaluation of a parallel hole collimator for a HiReSPECT: A dedicated small-animal SPECT.

Collimator geometry has an important contribution on the image quality in SPECT imaging. The purpose of this study was to investigate the effect of parallel hole collimator hole-size on the functional parameters (including the spatial resolution and sensitivity) and the image quality of a HiReSPECT imaging system using SIMIND Monte Carlo program. To find a proper trade-off between the sensitivity and spatial resolution, the collimator with hole diameter ranges of 0.3-1.5 mm (in steps of 0.3 mm) were used with a fixed septal and hole thickness values (0.2 mm and 34 mm, respectively). Lead, Gold, and Tungsten as the LEHR collimator material were also investigated. The results on a 99mTc point source scanning with the experimental and also simulated systems were matched to validate the simulated imaging system. The results on the simulation showed that decreasing the collimator hole size, especially in the Gold collimator, improved the spatial resolution to 18% and 3.2% compared to the Lead and the Tungsten, respectively. Meanwhile, the Lead collimator provided a good sensitivity in about of 7% and 8% better than that of Tungsten and Gold, respectively. Overall, the spatial resolution and sensitivity showed small differences among the three types of collimator materials assayed within the defined energy. By increasing the hole size, the Gold collimator produced lower scatter and penetration fractions than Tungsten and Lead collimator. The minimum detectable size of hot rods in micro-Jaszczak phantom on the iterative maximum-likelihood expectation maximization (MLEM) reconstructed images, were determined in the sectors of 1.6, 1.8, 2.0, 2.4 and 2.6 mm for scanning with the collimators in hole sizes of 0.3, 0.6, 0.9, 1.2 and 1.5 mm at a 5 cm distance from the phantom. The Gold collimator with hole size of 0.3 mm provided a better image quality with the HiReSPECT imaging.

A topological analysis of targeted In-111 uptake in SPECT images of murine tumors.

Single-photon emission computed tomography images of murine tumors are interpreted as the values of functions on a three-dimensional domain. Motivated by Morse theory, the local maxima of the tumor image functions are analyzed. This analysis captures tumor heterogeneity that cannot be identified with standard measures. Utilizing decreasing sequences of uptake values to filter the images, a modified form of the standard persistence diagrams for 0-dimensional persistent homology as well as novel childhood diagrams are constructed. Applying statistical methods to time series of persistence and childhood diagrams detects heterogeneous uptake of radioactive antibody within tumors over time and distinguishes uptake in two groups of mice injected with different labeled antibodies.