Thallium Scan Research Articles

LOGISTIC REGRESSION TECHNIQUE FOR CARDIOVASCULAR DISEASE PREDICTION

Cardiovascular diseases (CVDs) are the most common cause of death in the world. Over four out of five CVD deaths are due to heart attacks and strokes. CVD high mortality has led to about 17 million deaths worldwide. Several machine and deep learning techniques are used to classify the presence and absence of CVD. This paper presents a logistic regression (LR) technique for predicting the risk of heart diseases (HD). The goal is to create an LR algorithm and build a prediction model that would foretell the development of HD. The dataset included data on 207 patients, featuring the following: age, sex, chest pain type, blood pressure, cholesterol levels, fasting blood sugar > 120 mg/dl, electrocardiogram results, maximum heart rate, exercise-induced angina, ST depression, slope of the ST segment, number of major vessels colored by fluoroscopy, and thallium scan results. Using this dataset to train the LR technique, a robust model was created to accurately predict the existence of HD in new patients. With an accuracy of 81%, a precision of 83%, and a recall score of 76%, the accuracy, precision, and recall key metrics were used to evaluate the model's efficacy. The model’s accuracy was compared to alternative methods, such as K-Nearest Neighbors and Decision Tree classifiers, which yielded accuracy of 81% and 76%, respectively. The obtained results are of great significance for healthcare providers – the proposed model can assist in identifying those who are at high risk of heart diseases and allow for early implementation of prophylactic...

Comparison between multiple logistic regression and machine learning methods in prediction of abnormal thallium scans in type 2 diabetes

Comparison between multiple logistic regression and machine learning methods in prediction of abnormal thallium scans in type 2 diabetes

NIMG-88. THALLIUM 201 SINGLE PHOTON EMISSION CT (TI-SPECT) FOR DIFFERENTIATION OF MALIGNANT VERSUS BENIGN NERVOUS SYSTEM SPACE OCCUPYING LESIONS: A RETROSPECTIVE STUDY, SYSTEMATIC REVIEW, AND META-ANALYSIS

Abstract Importance Thallium-201 single-photon emission computed tomography (TI-SPECT) imaging has been used historically to distinguish malignant cerebral neoplasms from infectious etiologies. Objectives Our study aims to review existing literature and conduct a retrospective study and meta-analysis on the use of TI-SPECT to differentiate malignant from non-malignant nervous system lesions. Data Sources A retrospective study on use of TI-SPECT in differentiating malignant versus benign nervous system masses was conducted in two tertiary hospitals in the Philippines. Systematic review of relevant studies regarding TI-SPECT for brain and spinal cord lesions was also done. Meta-analysis was performed to generate pooled sensitivity and specificity. Study Selection All study types published in the English language were included – randomized controlled trials (RCTs), prospective/retrospective cohort studies, and case series and reports; abstract only studies were excluded. Studies that involved either pediatric and adult cases were considered. Data Extraction and Synthesis The study complied with the Meta-analysis of Observational Studies in Epidemiology (MOOSE) and Preferred Reporting Items for Systematic reviews and Meta-analyses (PRISMA) Guidelines. Main Outcome and Measure The primary outcome was sensitivity and specificity of TI-SPECT. This involved getting correlation of positive and negative thallium scan uptake with either biopsy results (if available) or diagnosis via clinical response to treatment (i.e. whether cases that were managed as infection or demyelination showed improvement on follow-up). RESULTS: Thirty-two (32) articles were qualitatively described and 25 datasets were subjected to meta-analysis. Pooled sensitivity and specificity were 0.89 (95% CI: 0.82-0.94) and 0.82 (95% CI: 0.74-0.88), respectively with an area under the curve (AUC) for diagnostic accuracy of 0.92. CONCLUSION: and Relevance Thallium scans may be utilized to discriminate malignant from benign nervous system lesions, especially, in cases with a >80% pre-test probability. Further studies are needed to validate this findings.

Multivariate sample similarity measure for feature selection with a resemblance model

Feature selection improves the classification performance of machine learning models. It also identifies the important features and eliminates those with little significance. Furthermore, feature selection reduces the dimensionality of training and testing data points. This study proposes a feature selection method that uses a multivariate sample similarity measure. The method selects features with significant contributions using a machine-learning model. The multivariate sample similarity measure is evaluated using the University of California, Irvine heart disease dataset and compared with existing feature selection methods. The multivariate sample similarity measure is evaluated with metrics such as minimum subset selected, accuracy, F1-score, and area under the curve (AUC). The results show that the proposed method is able to diagnose chest pain, thallium scan, and major vessels scanned using X-rays with a high capability to distinguish between healthy and heart disease patients with a 99.6% accuracy.

Abstract 9618: Prolonged Arterial Phase is the Culprit Pathology in Patients With Chest Pain, Elevated Troponin Level, Abnormal Thallium Scan and Patent Coronary Arteries: An Angiographic, Machine Learning Analysis for a Personalized Preventive Medicine Approach

Introduction: Many patients with acute coronary syndrome (ACS) presented with elevated troponin level and reversible changes in the thallium scan. When they patients underwent coronary angiogram, the results showed patent coronary arteries. WHY? Hypothesis: Could abnormal coronary flow explain ACS, abnormal thallium and patent coronary arteries? Methods: Patients with newly diagnosed ACS and abnormal Thallium scan underwent a new dynamic coronary angiogram. 10 patients without ACS, normal EF and no coronary artery disease served as control. In this new technique, the contrast and blood flow were recorded at 15 images per second. The first image was of the index artery completely filled with contrast. The subsequent images showed the blood in white color moving in over a background of black contrast. The arterial phase started when the blood began moving in and ended when the contrast disappeared from the distal arterial vasculature as the contrast was replaced by blood. The machine learning (ML) program had 2 models (built on Python). Model 1 was built based on U-net and Densenet-121 for vessel segmentation. Model 2 was used for classification of flow. The model 2 was trained based on the convolutional neural network. The data to be collected was the duration of the arterial phase and the recurrence of ACS within one year follow-up Results: 45 patients with ACS (elevated troponin level (50-100mg), reversible stress thallium), underwent coronary angiogram. The angiograms of 10 control patients showed a normal arterial phase (AP) of 1.56 sec. It was prolonged at 2.5sec in 45 patients with ACS (p<0.05). After 1 year follow-up, 35 patients had no further ACS if their LDL cholesterol was well controlled (<75mg%), blood pressure (BP<130mmHg) and the patients stopped smoking. In 10 patients who continued to have uncontrolled LDL, high BP and especially smoking, they developed ACS including death. Conclusions: In ACS patients, a prolonged arterial phase associated with reversible change in nuclear scan and normal coronary arteries identified the patients of high risk. Aggressive treatment of risk factors protected these patients of new ACS. Failure to control risk factors lead to repeat ACS. New trials are needed to confirm and guide new personalized medicine approach.

Spectrum of Disorders Leading to Sudden Cardiac Death

Objective: To determine the frequency of disorders leading to sudden cardiac death (SCD).
 Study Design: Cross-sectional study.
 Place and duration of study: Pathology Lab in collaboration with the Cardiology Department, AFIC & NIHD, Rawalpindi Pakistan, from Jan 2017 to Dec 2018.
 Methodology: A total of 305 cases of sudden cardiac death reported within the last 24 hours of a death to AFIC Rawalpindi were included consecutively. Cases with a history of extracardiac diseases leading to sudden death were excluded. Most of the included cases were diagnosed phenotypically based on clinical examination, biochemistry, ECG, echocardiography, angiography, thallium scan, electro-physiological studies, cardiac CT scan, MRI and routine autopsy whenever recommended.
 Results: Out of 305 cases, 197 (65%) were males and 108 (35%) females. Disorders leading to SCD were found in 178 (58.3%) cases due to ischemic heart disease (IHD), aortic dissection (0.7%), hypertrophic cardiomyopathy (HCM) (0.3%), dilated cardiomyopathy (DCM) (10.5%), congenital heart disease (12.1%) and valvular heart disease (7.9%). While in cardiac channelopathies, catecholaminergic polymorphic ventricular tachycardia (CPVT) in 5 (1.6%) and congenital long QT syndrome (LQTS) in 2 (0.7%) cases. However, 24 (7.9%) cases remained as sudden unexplained deaths (SUD).
 Conclusion: In our setup, ischemic heart disease and dilated cardiomyopathy were the commonest causes of sudden cardiac death, followed by congenital heart disease and valvular heart diseases.

Atrioventricular (AV) block and sinus arrest associated with dipyridamole infusion.

The use of dipyridamole for thallium-201 imaging has proved very successful in demonstrating coronary arterial disease, and a combination of dipyridamole and dynamic exercise is becoming widely used. Dipyridamole is safe when given intravenously, although transient noncardiac side effects are common; side effects such as chest pain, headache, and dizziness. These side effects are mostly mild, and can be treated with aminophylline. We describe a 45-year-old woman with normal baseline electrocardiography (ECG) and unremarkable physical examination, referred for myocardial thallium scan with dipyridamole. A few seconds after infusion of dipyridamole, her ECG developed first-degree atrioventricular (AV) block, then, 2:1 AV block, complete heart block (CHB), and sinus arrest. After aminophylline infusion, junctional escape rhythm was seen, and a few seconds later, rhythm changed to sinus rhythm. Thallium scan was negative for ischemia. High-grade AV block after dipyridamole has been described in few case reports, and mostly was associated with transient myocardial ischemia; it seems that the presence of conduction abnormalities at baseline is a risk factor. But in our case, the sinus arrest and AV block occurred without evidence of ischemia in myocardial perfusion imaging, and we think it can be an unwanted complication of dipyridamole; clinicians should be aware of bradyarrhythmia as a possible complication of dipyridamole. An alternative explanation is that this arrhythmia can be caused by vagal activity; and another possibility is that the imaging study was false negative.

Giant Coronary Artery Aneurysm: A Successful Diagnosis

Coronary artery aneurysms (CAAs) are rare, with giant CAAs being even rarer. The precise pathophysiology of this phenomenon is still unknown. CAAs are seldom reported life-threatening abnormalities of the cardiovascular system. We herein present a case of a 74-year-old man who presented at the hospital complaining of chest pain. An adenosine thallium scan revealed a small, reversible defect in the inferior wall of the left ventricle extending into the apex, consistent with ischemia. Echocardiography uncovered a large right coronary artery (RCA) aneurysm, measuring 5.6 × 7.5 cm. Diagnostic coronary angiography confirmed the presence of a large RCA aneurysm and aneurysmal dilation of the left anterior descending and circumflex arteries with no flow-limiting lesions. A reversed saphenous vein interposition graft was placed from the ascending aorta to the right posterior descending artery. The RCA aneurysmal sac was resected and sent to pathology, which uncovered myxoid degeneration of the media as well as thrombus formation. No complications were encountered during the procedure. Early diagnosis is vital to avoid fatal complications of CAAs, and therapeutic approaches are currently individualized in view of absence of evidence-based management strategies.

A Radiological Scoring System for Differentiation between Enchondroma and Chondrosarcoma.

Simple SummaryBackground: It is challenging to differentiate between enchondromas and atypical cartilaginous tumors (ACTs)/chondrosarcomas. Methods: To evaluate the diagnostic usefulness of radiological findings for differentiation between enchondromas and chondrosarcomas, correlations between various radiological findings and final diagnoses were investigated. Based on the correlations, a scoring system combining these findings was developed. Results: In a cohort of 81 patients, periosteal reaction on X-ray, endosteal scalloping and cortical defect on CT, extraskeletal mass, multilobular lesion, abnormal signal in adjacent tissue on MRI, and increased uptake in bone scan and thallium scan was significantly correlated with final diagnoses. Based on the correlations, a radiological scoring system combining radiological findings was developed. In another cohort of 17 patients, the sensitivity, specificity, and accuracy of the radiological score rates for differentiation between enchondromas and chondrosarcomas were 88%, 89%, and 88%, respectively. Conclusion: Comprehensive assessment combining radiological findings is recommended to differentiate between enchondromas and ACTs/chondrosarcomas.Background: It is challenging to differentiate between enchondromas and atypical cartilaginous tumors (ACTs)/chondrosarcomas. In this study, correlations between radiological findings and final diagnosis were investigated in patients with central cartilaginous tumors. Methods: To evaluate the diagnostic usefulness of radiological findings, correlations between various radiological findings and final diagnoses were investigated in a cohort of 81 patients. Furthermore, a new radiological scoring system was developed by combining radiological findings. Results: Periosteal reaction on X-ray (p = 0.025), endosteal scalloping (p = 0.010) and cortical defect (p = 0.002) on CT, extraskeletal mass (p < 0.001), multilobular lesion (p < 0.001), abnormal signal in adjacent tissue (p = 0.004) on MRI, and increased uptake in bone scan (p = 0.002) and thallium scan (p = 0.027) was significantly correlated with final diagnoses. Based on the correlations between each radiological finding and postoperative histological diagnosis, a radiological scoring system combining these findings was developed. In another cohort of 17 patients, the sensitivity, specificity, and accuracy of the radiological score rates for differentiation between enchondromas and ACTs/chondrosarcomas were 88%, 89%, and 88%, respectively (p = 0.003). Conclusion: Radiological assessment with combined radiological findings is recommended to differentiate between enchondromas and ACT/chondrosarcomas.

The role of Thallium-201 scintigraphy and Tc-99m pentavalent dimercaptosuccinic acid in diagnosis and grading of chondrosarcoma

PurposeDistinguishing between enchondromas and low-grade (grade 1) chondrosarcomas can be challenging. The aim of this study was to investigate the role of Thallium-201 scintigraphy and Technetium-99 m pentavalent dimercaptosuccinic acid (Tc-99 m DMSA (V)) in the diagnosis and grading of chondrosarcomas. Methods232 consecutive patients with pathologically proven cartilaginous tumours between the years 2000 and 2018 were evaluated. We included 197 patients (101 males and 96 females; median age 50 years; range 15–86 years) who underwent Thallium-201(n = 193) and/or Tc-99 m DMSA (V) scanning (n = 67). Increased uptake was defined as uptake greater than background. The reference standard was the histopathological assessment based on a grading system (grade 1–3). Data was analysed using multivariate modelling. ResultsThere were 46 patients with enchondromas and 151 with chondrosarcomas. Of those, 64 (enchondroma n = 21, chondrosarcoma n = 43) underwent both Thallium-201 and Tc-99 m DMSA (V). Thallium-201 uptake had 7.92 times greater odds of grade 1 chondrosarcomas than enchondromas. Thallium-201 uptake was significantly associated with the odds of a higher grade chondrosarcoma (grade 2–3). DMSA (V) positivity was associated with 4.75 times the odds of a chondrosarcoma diagnosis over enchondroma (p = 0.024). DMSA (V) uptake revealed no association with chondrosarcoma grading. ConclusionLow-grade chondrosarcomas continue to pose a diagnostic dilemma. Thallium-201 scans may identify malignancy in benign appearing tumours as well as differentiate between low-grade and high-grade chondrosarcomas in said malignancies. DMSA (V) may be useful in distinguishing between benign and malignant entities as a whole.

13. Prevalence of cardiopulmonary comorbidities in end stage liver disease patients worked up for liver transplantation

Background and Aims: It was thought previously that cardiovascular diseases were rare in cirrhotic patients in view of peripheral vasodilatation. However recent studies have shown that up to one fourth of these patients may have critical coronary artery stenosis and half of these patients might die during perioperative period due to the cardiac complications. Similarly, these patients may have various obstructive or restrictive pulmonary diseases. We aimed this study to estimate prevalence of various cardiac and pulmonary diseases in patients with end stage liver disease worked up for liver transplantation. Methods: Clinical and laboratory data of 70 patients with decompensated cirrhotic patients of various etiology who were worked up for liver transplantation between 2010 January to 2018 June were enrolled into study. All the patients underwent various blood and imaging investigations. For cardiopulmonary assessment these patients underwent various noninvasive and invasive investigations including electrocardiography, echocardiography, stress thallium scan, coronary angiography and pulmonary function tests and arterial blood gas analysis. Results: Six of 70 (8.4%) patients had coronary artery disease. Two (3%) patients had systolic dysfunction. Eighteen (26%) patients had restrictive pulmonary disease out of which eleven (16%) had moderate restrictive pulmonary disease while eight (10%) had mild restrictive pulmonary disease. Only one (1.5%) patient had severe restrictive pulmonary disease and one (1.5%) had obstructive pulmonary disease. Conclusion: Coronary artery disease is uncommon in end stage liver disease patients. However mild to moderate restrictive pulmonary diseases may be common in these population. The authors have none to declare.

Diagnosis and Identification of Risk Factors for Heart Disease Patients Using Generalized Additive Model and Data Mining Techniques

Background: Yearly death rate is increasing due to heart disease. Major factors for the increasing death rate due to heart disease are (a) misdiagnosed by the medical doctors or (b) ignorance by the patients. Heart diseases can be described as any kind of disorder which affects the heart. Methods: The dataset of ‘statlog’ from the UCI Machine Learning with 270 patients related to heart disease isused in this article. The dataset comprises attributes of patients diagnosed with heart diseases. The diagnosis was used to confirm whether heart disease is present or absent in the patient. The present article aims to identify the risk factors/variables which influence this diagnosis. Classification is a very important part of the disease diagnosis but it is also relevant to identify the risk factors/variables. Two classification techniques namely Support Vector Machines (SVM), Multi-Layer Perceptrons ensembles (MLPE) and one advanced regression technique,Generalized additive model (GAM) with binomial distribution and‘logit’ link have been introduced for diagnosis and risk factors/variables identification. Results: GAM explains 65% deviance with adjusted R square value 0.70 approximately. Sensitivity analysis has been performed under SVM, which is the best model for this dataset with approximately 85% classification accuracy rate. MLPE gives 82% classification accuracy rate approximately.Maximum heart rate, vessel, old peak, chest pain, thallium scan are the most important factors/variables find through both sensitivity analysis under SVM and GAM. Conclusion: The present article attempt to remove some new information regarding heart disease through probabilistic modeling which may provide better assistance for treatment decision making using the individual patient risk factors and the benefits of a specific treatment. These findings may help the medical practitioners for better medical treatment.

Does Myocardial Scan with Technetium Lead to Radio Adaptive Response Among Patients Who Are Undergoing Thallium Scan? (Cytogenetic Study)

Background: Low dose radiation will induce adaptation and following exposure to an adaptive dose, the cells are more resistance to following challenging doses. This phenomenon is known as radio-adaptive response. The aim of this study was to investigate the percentage of apoptotic cells in the peripheral blood samples of the patients which undergo myocardial perfusion imaging with Tc-99m prior to thallium scan to assess the induction of radio-adaptive response. Methods: 97 samples from 74 patients, referred to nuclear medicine center of Mazandaran heart hospital for myocardial perfusion imaging which had no history of diagnostic, therapeutic, occupational and radioactive exposures during past two years, were provided. The participants were classified into four groups including control, technetium, thallium and the last group were the patients that examined by technetium followed by thallium. Then 2 mL Peripheral blood samples were obtained, the samples were studied by neutral comet assay with one-way ANOVA. Results: The mean percent of apoptotic cells in the groups 2, 3, 4 were more than the controls and the mean percent of apoptotic cells in the patients who examined with 201Tl were more than other groups but the mean percent of apoptotic cells in the group 4 (99mTc before 201Tl) was less than that group 3(just examinated by 201Tl) and this difference was significant statistically. Conclusions: These findings suggest that exposure to Tc-99m could induce a radio-adaptive response against the exposure of Tl-201.

TCTAP C-169 Successful Revascularization of Left Main Bifurcation and Right Coronary Artery Chronic Total Occlusion Using Rotablator Atherectomy

### Patient initials or identifier number Y. S. ### Relevant clinical history and physical exam The 86 years-old female was admitted for scheduled CAG study due to effort angina (CCS III ) refractory to medical therapy and positive Thallium scan which revealed stress-induced ischemia in

Radio-adaptive Response in Myocardial Perfusion Imaging Induced by Technetium-99m.

Purpose of the Study:Low dose radiation will induce adaptation and following exposure to an adaptive dose, the cells are more resistance to following challenging doses. This phenomenon is known as radio-adaptive response. The aim of this study was to investigate the percentage of apoptotic cells in the peripheral blood samples of the patients which undergo myocardial perfusion imaging (MPI) with technetium-99m (Tc-99m) before thallium scan to assess the induction of radio-adaptive response.Materials and Methods:In this study, 97 samples from 74 patients, referred to nuclear medicine center of Mazandaran Heart Hospital for MPI, which had no history of diagnostic, therapeutic, occupational, and radioactive exposures during past 2 years, were provided. The participants were classified into four groups including control, patients which were scanned solely with technetium, the patients which examined by thallium and the last group were the patients that examined by technetium followed by thallium. Then 2 ml Peripheral blood samples were obtained, and after 24 h incubating, the samples were studied by neutral comet assay. Statistical analysis was carried out using Student's t-test along with one-way analysis of variance.Results:The mean percentage of apoptotic cells in the exposed groups were higher than the control. Furthermore, among exposed groups, the apoptotic cells in thallium group were more than others and this index was significantly lower in the group which was undergone technetium administration before thallium scan.Conclusions:These findings suggest that exposure to Tc-99m could induce a radio-adaptive response against the exposure of thallium-201.

Free radial artery as an alternate conduit in CABG

Objective: This study was under taken to explore the potential of the Free Radial Graft as a safe efficient and suitable alternative conduit in coronary artery bypass grafting incase of in availability of the more established conduits like the IMA and Great Saphenous Vein graft especially in redo surgery. Method: This prospective randomized single center trial was conducted on three groups of patients under going CABG. The study was conducted from 1st January 1999 to December 2002.The first group A (n=15 with mean age of 47.05±8.35years) Radial artery was used for grafting in Right and Left sided grafts except the LAD. In the second group B (n=15 with a mean age of 54.80±11.14 years) Great Saphenous Vein was used for grafting in Right and Left sided grafts except the LAD. In the third group C (n=20 with a mean age of 55.93± 11.14 years) IMA was only grafted to LAD. Proximal ends of both the GSV and the Radial Artery were anastomosed to the Aorta. All patients were male . Follow up was done in these patien ts both by non invasive and invasive methods such as ETT , Thallium scan , Angiography. Comparison was mainly done between the Radial artery and the Great Saphenous Vein taking as granted that the IMA g the best graft for the LAD in all cases. Results: IMA was always applied to LAD in all patients in the three groups. In group (A) Radial Artery was grafted to RCA in 5 (33.3%) pts. Diagonal in 4 (26.7%)pts. Obtuse Marginal 12(80%) pts. And PDA 3 (20%) pts. In group (B) Great Saphenous Vein was grafted to RCA in 6(40%)pts. Circumflex 1(6.7%)pts. Diagonals 2 (13.3%) pts. Obtuse marginals 6 (40%) pts. And on PDA 4(20%) pts. All patients were regularly followed up for 18 months to 24 months. Post operative angina was reported in 2 (13.3%)pts. in group A and 5(33.3%) pts. In group B (p=0549). ETT was done in all these pts. Was positive in 1(6.7%) in group A and 2 (13.3%) in group B (p=0.309). Thallium scan was done in all the study population and was found positive in 4 (26.7%) in group A and 5 (33.3%) in group B Patients(p=0.265). Coronary angiograms were done on 10 patients out of each group. In group A the grafts were patent in 9 patients (90%). In the group B the grafts were found patent in 8 (86%) patients.(p=0.543). Moderate Graft stenosis was found in 01 patient in group B and none in group A (p=0.35). Totally blocked grafts were found in 01 patients in each group (p=1.00).

Debate: Molecular cardiac imaging is ready for the prime time con between wishful thinking and reality

Molecular imaging is defined as the non-invasive visualization, characterization, and measurement of biological processes at the molecular and cellular levels in humans. According to this definition, all nuclear cardiology examinations, from classic myocardial perfusion thallium scans to advanced PET studies of cardiovascular metabolism and function, can be considered molecular imaging techniques. From this perspective, it is a misconception to apply the definition of molecular cardiac imaging, only to innovative new technologies to come. Needless to say that myocardial perfusion SPECT, a classic cardiac molecular imaging technology, has been in Prime Time for decades. Having said so, it is remarkable that over the years, molecular imaging in medicine has been often unconsciously driven by wishful thinking. Typically, when an exciting new molecular imaging technology is proposed, all may seem to go well for some time, but reality eventually sets in, showing that initial expectations were based on wishes and hopes rather than on appropriate appraisal of the clinical needs and health care scenarios. Beyond wishful thinking, new molecular cardiovascular imaging techniques need to address significant issues prior to entering Prime Time. To be ready for Prime Time, new molecular cardiac imaging examinations have to overcome several major hurdles:

SU-C-201-04: Quantification of Perfusion Heterogeneity Based On Texture Analysis for Fully Automatic Detection of Ischemic Deficits From Myocardial Perfusion Imaging

Purpose: Texture-based quantification of image heterogeneity has been a popular topic for imaging studies in recent years. As previous studies mainly focus on oncological applications, we report our recent efforts of applying such techniques on cardiac perfusion imaging. A fully automated procedure has been developed to perform texture analysis for measuring the image heterogeneity. Clinical data were used to evaluate the preliminary performance of such methods. Methods: Myocardial perfusion images of Thallium-201 scans were collected from 293 patients with suspected coronary artery disease. Each subject underwent a Tl-201 scan and a percutaneous coronary intervention (PCI) within three months. The PCI Result was used as the gold standard of coronary ischemia of more than 70% stenosis. Each Tl-201 scan was spatially normalized to an image template for fully automatic segmentation of the LV. The segmented voxel intensities were then carried into the texture analysis with our open-source software Chang Gung Image Texture Analysis toolbox (CGITA). To evaluate the clinical performance of the image heterogeneity for detecting the coronary stenosis, receiver operating characteristic (ROC) analysis was used to compute the overall accuracy, sensitivity and specificity as well as the area under curve (AUC). Those indices were compared to those obtained from the commercially available semi-automatic software QPS. Results: With the fully automatic procedure to quantify heterogeneity from Tl-201 scans, we were able to achieve a good discrimination with good accuracy (74%), sensitivity (73%), specificity (77%) and AUC of 0.82. Such performance is similar to those obtained from the semi-automatic QPS software that gives a sensitivity of 71% and specificity of 77%. Conclusion: Based on fully automatic procedures of data processing, our preliminary data indicate that the image heterogeneity of myocardial perfusion imaging can provide useful information for automatic determination of the myocardial ischemia.

A study on the role of ECG, echo and dipyridamole thallium scan in identifying early myocardial damage in systemic sclerosis

A study on the role of ECG, echo and dipyridamole thallium scan in identifying early myocardial damage in systemic sclerosis

The efficacy and safety of a chest pain protocol for short stay unit patients: A one year follow-up.

The Alfred Emergency Short Stay Unit initiated a chest pain protocol for patients presenting with chest pain to risk stratify for acute coronary syndrome (ACS). A 30-day follow-up of patients discharged with low-or-intermediate risk of ACS demonstrated no deaths or ACS. The purpose of this study was to evaluate the long-term safety of the chest pain protocol, a one year follow-up was undertaken. A questionnaire was designed for the one-year follow-up and it was administered via a telephone interview by emergency nurses to document adverse cardiac events and health care utilisation. From 297 patients, 224 (75%) were contacted 12 months following discharge. There was one death from stroke (0.4%; 95% confidence interval (CI): 0.01-2.5%) and another from an unknown cause. Five patients had been diagnosed with atrial fibrillation (2.2%; 95% CI: 0.7-5.1%), two patients had an acute myocardial infarction (0.9%; 95% CI: 0.03-2.1%) and four were diagnosed with angina (1.8%; 95% CI: 0.9-3.2%). Nearly half (n=103, 46%; 95% CI: 39.5-52.5%) had returned to the emergency department (ED) for various conditions including 42 patients with further chest pain. Ninety-six patients (43%; 95% CI: 39.3-52.7%) had specialist referrals and 124 investigations were performed. Thirty-four patients had cardiology referrals (15%; 95% CI: 10.7-20.5%) and 25 patients had gastroenterology referrals (11%; 95% CI: 7.3-16.0%). Diagnostic cardiac tests were performed on 38 patients: coronary angiography (n=10), 24-hour Holter monitoring (n=17), 24-hour blood pressure (BP) monitoring (n=4), thallium scans (n=5), exercise stress test (n=1) and CT scan (n=1). Patients had a low risk of adverse events 12 months after discharge but substantial continuing health care utilization was observed. Complete assessment by health care professionals prior to discharge may help mitigate representations.