Evaluation of the diagnostic efficacy of 18 F-Fluorine-2-Deoxy-D-Glucose PET/CT for lung cancer and pulmonary tuberculosis in a Tuberculosis-endemic Country.

OBJECTIVE: To determine the diagnostic efficacy of 18 F-FDG PET/CT in distinguishing between pulmonary tuberculosis (PTB) and lung cancer in solitary pulmonary nodule (SPN) in a country with a high prevalence of PTB. METHODS: Patients with SPN who underwent 18 F-FDG PET/CT imaging were retrospectively included in the study. The final diagnosis was established by histopathology. A linear regression equation was fitted to a scatter plot of size and SUVmax of lung cancer and PTB. ROC was used to determine the optimal cutoff values and diagnostic accuracy of 18 F-FDG PET/CT in PTB and lung cancer. RESULTS: About 514 patients were included with the mean age of 57.5 ± 10.6 years. Four hundred and seventy-five cases were diagnosed as lung cancer, and 39 cases were PTB by histopathology. 18 F-FDG PET/CT had sensitivity, specificity, and diagnostic accuracy of 96.0%, 48.7%, and 92.0%, respectively. Utilization of SUVmax ≥2.5 in SPN resulted in 2 and 11 false positives cases of lung cancer and PTB, respectively, whereas SUVmax <2.5 resulted in 18 and 10 false-positive cases of lung cancer and PTB, respectively. The SUVmax and the size of short-axis in the lung cancer group were statistically higher than those in the PTB group. The linear regression equation parameters indicated the slope of the regression line of lung cancer was greater than that of PTB. The ROC curve demonstrated the SUVmax cutoff values of 4.85 and 2.25 for lung cancer and PTB, respectively for predicting the diagnostic accuracy of 18 F-FDG PET/CT. CONCLUSION: 18 F-FDG PET/CT has a higher sensitivity and diagnostic accuracy for malignant SPN. However, it has high false-positive rate and low specificity in tuberculosis endemic areas. Neither SUVmax nor the sizes of the nodules are valuable parameters for distinguishing between lung cancer and PTB. However, the SPN with larger short-axis and higher SUVmax would be inclined to malignant tumor.

The role of Cardiac Magnetic Resonance (CMR) in the diagnosis of cardiomyopathy: A systematic review.

Background: Myocardial pathologies are significant causes of morbidity and mortality in patients worldwide. Ischemic and non-ischemic cardiomyopathies have become a worldwide epidemic of the 21st century with an increasing impact on health care systems. The 2012 European Society of Cardiology and 2013 American College of Cardiology Foundation/American Heart Association guidelines provide current therapy guidance to reduce mortality and morbidity. Methods: This was a systematic review involving cardiac magnetic resonance (CMR) studies for the diagnosis of cardiomyopathy from January 2013 to April 2017. Out of 62 reviewed studies, only 12 were included in our study. Results: The average sensitivity and specificity of CMR in the diagnosis of cardiomyopathy was 86.75% (95% confidence interval [CI], 70.30% to 92.58%) and 81.75% (95% CI, 73.0% to 87.6%), respectively, and the positive predictive and negative predictive values were 80.17% and 86.75%, respectively. Conclusion: Despite some limitations, our study shows that CMR has high sensitivity, specificity, and positive predictive value in diagnosing different types of cardiomyopathy. CMR may be used to differentiate types of cardiomyopathy, accurately quantify the chamber dimensions, volumes, and cardiac function, which make it useful for prognosis as well.

Preclinical Evaluation of a Fluorine-18 (18F)-Labeled Phosphatidylinositol 3-Kinase Inhibitor for Breast Cancer Imaging.

Breast cancer is one of the commonest malignancies in women, especially in middle-aged and elderly women. Abnormal activation of the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKt/mTOR) pathway has been found to be involved in breast cancer proliferation. Pictilisib (GDC-0941) is a potent inhibitor of PI3K with high affinity and is undergoing phase 2 clinical trials. In this study, we aimed to develop a noninvasive PI3K radiotracer to help determine the mechanism of the PI3K/AKt/mTOR pathway to aid in diagnosis. We designed a new 18F-radiolabeled radiotracer based on the structure of pictilisib, to evaluate noninvasively abnormal activation of the PI3K/AKT/mTOR pathway. To increase the water solubility, and to decrease hepatobiliary and gastrointestinal uptake of the tracer, pictilisib was modified with triethylene glycol di(p-toluenesulfonate) (TsO-PEG3-OTs) to obtain TsO-PEG3-GDC-0941 as the precursor for 18F labeling. A nonradiolabeled reference compound [19F]-PEG3-GDC-0941 was also prepared. Breast cancer cell lines, MCF-7 and MDA-MB-231, were used as high- and low-expression PI3K models, respectively. PET imaging and ex vivo biodistribution assays of [18F]-PEG3-GDC-0941 in MCF-7 and MDA-MB-231 xenografts were also performed, and the results were compared. The precursor compound and reference standard compound were successfully synthesized and identified using NMR and mass spectroscopy. The 18F radiolabeling was achieved with a high yield (61 ± 1%) at a high molar activity (2100 ± 100 MBq/mg). MicroPET images and biodistribution studies showed a higher uptake of the radiotracer in MCF-7 tumors than in MDA-MB-231 tumors (7.56 ± 1.01%ID/g vs 4.07 ± 0.68%ID/g, 1 h postinjection). Additionally, the MCF-7 tumor uptake was significantly decreased when a blocking dose of GDC-0941 was coinjected, indicating high specificity. The liver was found to be the major excretory organ with 5.82 ± 0.88%ID/g at 30 min postinjection for MCF-7 mice. This radiotracer holds great potential for patient screening, diagnosis, and therapy prediction of PI3K-related diseases.

The association of 18F-FDG PET/CT and biomarkers in confirming coronary microvascular dysfunction.

OBJECTIVE: The purpose of this study is to evaluate the association between PET/CT CFR and biomarkers combined in confirming the diagnosis of coronary microvascular dysfunction. RESULTS: A total of 28 patients (21 males and 7 females) were included in this descriptive observational study (both qualitative and quantitative). The mean patient age was 55.50 ± 10.21 years (range 27-70 years) and the median was 56.5 years (range 49-63 years). All patients underwent Echo, CAG and PET/CT scan. Chest tightness was the most common symptom in our study. Most patients had normal blood pressure (n = 18, 64.3%) while only (n = 10, 37.5%) had hypertension, and (n = 1, 3.6%) had diabetes mellitus. The mean HDL in CMVD (n = 25) and non-CMVD (n = 3) were 1.30 ± 0.39 and 1.08 ± 0.95, respectively, indicating that the difference between the groups was statistically significant (p = 0.04). Similarly, the mean HBA1c- (glycated haemoglobin) in CMVD (n = 25) and non-CMVD (n = 3) were 5.6 ± 0.53 and 5.0 ± 0.26, respectively, with (p = 0.03). Our findings managed to show the association between biomarkers and PET/CT CFR in confirming the diagnosis of coronary microvascular dysfunction.

Clinical significance of PET-CT coronary flow reserve in diagnosis of non-obstructive coronary artery disease.

OBJECTIVE: To improve current knowledge of coronary flow reserve and non-obstructive coronary artery disease in terms of definition, features and clinical implications of measurement of coronary flow reserve (CFR), is an integrated measure of focal, diffuse, and small vessel coronary artery disease, can also be explained as a calculated ratio of hyperaemic to rest absolute myocardial blood flow. Non-obstructive coronary artery disease is defined as atherosclerotic plaque that does not obstruct blood flow or result in anginal symptoms. We also aimed at knowing the significance of PET in diagnosing coronary microvascular disease. RESULTS: In our study 92% were between 41 and 60 years. 83% were males and 17% females, more patients had hypertension about 50%, few had diabetes mellitus about 16%, while those with both hypertension and diabetes mellitus were 17%. About 83% had ST segment and T wave changes on ECG. All patients and controls had normal coronaries on coronary angiography TIMI 3 flow. On further investigation by Positron emission tomography/CT we found out 58% had abnormal CFR and 42% had normal coronary flow reserve. Our findings indicate PET/CT coronary flow reserve concept provides a platform for the diagnosis of non-obstructive coronary artery disease in patients with signs and symptoms of ischemia without angiographic obstructive CAD.

Prognostic Value of Volume-Based Positron Emission Tomography/Computed Tomography in Nasopharyngeal Carcinoma Patients after Comprehensive Therapy.

Objective: We assessed the prognostic value of standardized uptake value (SUV) and volume-based methods including whole-body metabolic tumor volume (WBMTV) and whole-body total lesion glycolysis (WBTLG) using 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) of patients with nasopharyngeal carcinoma (NPC) after therapy. Methods: A total of 221 posttherapy NPC cases were enrolled, all of whom had undergone PET/CT scanning and follow-up in this retrospective study. The diagnostic results of PET/CT were analyzed and compared with histopathological diagnosis or clinical follow-up. Receiver operator characteristic curves, the Kaplan-Meier method, and the log-rank test were used to assess the optimal cutoff values for WBMTV and WBTLG to identify independent predictors of survival. Results: The detection rates of the threshold SUV were 2.5, 20%, and 40%, and SUV background methods were 65.6% (378/576), 80.2% (462/576), 71.5% (412/576), and 90.4% (521/576), respectively (P < 0.005). Patients with a WBMTV < 8.10 and/or a WBTLG < 35.58 had significantly better 5-year overall survival than those above the cutoffs (90.7% versus 51.2%, P < 0.001; 91.7% versus 50.4%, P < 0.001), respectively. Multivariate Cox regression modeling showed both WBTLG (RR, 1.002; P = 0.004) and age (RR, 1.046; P = 0.006) could be used to predict overall survival. WBTLG (RR, 1.003; P < 0.001) may have predictive relevance in estimating disease-free survival. Conclusions: SUV volume-based threshold background methodology had a significantly higher detection rate for metastatic lesions. WBTLG could be used as an independent prognostic indicator for posttherapy NPC.

Convergence angles of all-ceramic full crown preparations performed in Dubai private practice.

BACKGROUND: This study aimed to determine the degree of taper and total occlusal convergence angles (TOC) for all-ceramic bonded crown preparations carried out by private practitioners in Dubai, UAE. MATERIAL AND METHODS: A convenience sample of all-ceramic crown preparations carried out by private dental practitioners were scanned (Carestream CS 3500) from casts and the digital images assessed. The degree of taper was measured on the axial walls of each crown preparation and the bucco-lingual and mesio-distal convergence angles subsequently calculated. RESULTS: A total of 154 dentists prepared a total of 206 crown preparations (72 anterior, 134 posterior). The mean convergence angles mesio-distally for all preparations was 24.6° (sd 11.8º), and for the bucco-lingual it was 32.6° (sd 15.3°). The mean TOC was 28.6°. In anterior preparations, the mean bucco-lingual convergence angle was 38.8° (sd 12.2°) compared to 29.3° (sd 15.5°) for posterior preparations (p<0.001). Mean mesio-distal convergence anteriorly was 20.6° (sd 10.18°) compared to 26.7° (sd 12.16°) posteriorly (p<0.001). Distal and buccal taper were significantly greater on posterior teeth (<0.001) compared to anteriors whereas lingual taper was greater on anterior teeth (p<0.001). Mesial taper was not different. Premolars had significantly lower convergence values compared to other teeth. CONCLUSIONS: Bucco-lingual and mesio-distal convergence angles significantly exceeded the clinically acceptable convergence angle of between 10° and 22°. Greater axial taper is recommended for resin bonded all-ceramic crowns but reliance on adhesion in such preparations rather than parallelism may reduce retention and have increased biologic cost to pulp health. Key words:All-ceramic crown preparations, convergence angles, axial taper.

The role of cardiac magnetic resonance (CMR) in the diagnosis of cardiomyopathy: A systematic review.

BACKGROUND: Myocardial pathologies are significant causes of morbidity and mortality in patients worldwide. Ischemic and non-ischemic cardiomyopathies have become a worldwide epidemic of the 21st century with an increasing impact on health care systems. The 2012 European Society of Cardiology and 2013 American College of Cardiology Foundation/American Heart Association guidelines provide current therapy guidance to reduce mortality and morbidity. METHODS: This was a systematic review involving cardiac magnetic resonance (CMR) studies for the diagnosis of cardiomyopathy from January 2013 to April 2017. Out of 62 reviewed studies, only 12 were included in our study. RESULTS: The average sensitivity and specificity of CMR in the diagnosis of cardiomyopathy was 86.75% (95% confidence interval [CI], 70.30% to 92.58%) and 81.75% (95% CI, 73.0% to 87.6%), respectively, and the positive predictive and negative predictive values were 80.17% and 86.75%, respectively. CONCLUSION: Despite some limitations, our study shows that CMR has high sensitivity, specificity, and positive predictive value in diagnosing different types of cardiomyopathy. CMR may be used to differentiate types of cardiomyopathy, accurately quantify the chamber dimensions, volumes, and cardiac function, which make it useful for prognosis as well.

18F-Fluoro-2-Deoxy-d-Glucose PET/Computed Tomography Evaluation of Lung Cancer in Populations with High Prevalence of Tuberculosis and Other Granulomatous Disease.

Pulmonary tuberculosis infects one-third of world's population and is responsible for the high mortality and morbidity in developing countries. The presence of a high number of macrophages and lymphocytes in active tuberculosis granulomas is associated with high uptake of 18F-fluoro-2-deoxy-d-glucose on PET imaging mimicking lung cancer. In many cases, radiological features of pulmonary tuberculosis are undistinguishable from lung cancer, which makes the diagnosis difficult. Clinical history and computed tomographic (CT) findings on a hybrid PET/CT are as important as findings on a PET in the diagnosis of lung cancer.

Fluorine-18 fluorodeoxyglucose positron emission tomography-computed tomography in monitoring the response of breast cancer to neoadjuvant chemotherapy: a meta-analysis.

INTRODUCTION: To evaluate the diagnostic performance of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) in monitoring the response of breast cancers to neoadjuvant chemotherapy. METHODS: Articles published in medical and oncologic journals between January 2000 and June 2012 were identified by systematic MEDLINE, Cochrane Database for Systematic Reviews, and EMBASE, and by manual searches of the references listed in original and review articles. Quality of the included studies was assessed by using the quality assessment of diagnosis accuracy studies score tool. Meta-DiSc statistical software was used to calculate the summary sensitivity and specificity, positive predictive and negative predictive values, and the summary receiver operating characteristics curve (SROC). RESULTS: Fifteen studies with 745 patients were included in the study after meeting the inclusion criteria. The pooled sensitivity and specificity of FDG-PET or PET/CT were 80.5% (95% CI, 75.9%-84.5%) and 78.8% (95% CI, 74.1%-83.0%), respectively, and the positive predictive and negative predictive values were 79.8% and 79.5%, respectively. After 1 and 2 courses of chemotherapy, the pooled sensitivity and false-positive rate were 78.2% (95% CI, 73.8%-82.5%) and 11.2%, respectively; and 82.4% (95% CI, 77.4%-86.1%) and 19.3%, respectively. CONCLUSIONS: Analysis of the findings suggests that FDG-PET has moderately high sensitivity and specificity in early detection of responders from nonresponders, and can be applied in the evaluation of breast cancer response to neoadjuvant chemotherapy in patients with breast cancer.