Chi-Lun Ko

Intratumoral Heterogeneity of Pretreatment 18F-FDG PET Images Predict Disease Progression in Patients With Nasal Type Extranodal Natural Killer/T-cell Lymphoma.

Purpose The aim of this study was to investigate whether the textural features of pretreatment 18F-FDG PET images can predict prognosis for nasal type extranodal natural killer/T-cell lymphoma (ENKTL). Materials and Methods A retrospective analysis of the pretreatment 18F-FDG PET images of the patients with newly diagnosed nasal type ENKTL from 2008 to 2013 was conducted. Progression-free survival (PFS) was the main outcome measure. The primary tumor was identified and then delineated using the 40% maximum standardized uptake value (SUVmax) thresholding method. The textural features of the pretreatment 18F-FDG PET images were extracted. The prognostic significance of the textural features of the PET images were examined using the receiver operating characteristic (ROC) curves and Cox regression analysis. P values <0.05 were considered statistically significant. Results In total, 17 patients were enrolled, among whom 11 showed disease progression and 6 died from the disease during the median follow-up period of 27.2 months. Dissimilarity and low-intensity short-zone emphasis (LISZE) were identified as independent predictors of PFS by using the ROC curves and multivariate Cox analysis after adjusting for the clinical variables. Conclusions Dissimilarity and LISZE were the significant predictors of disease progression in patients with nasal type ENKTL and can improve their prognostic stratification.

New Trends in Radionuclide Myocardial Perfusion Imaging

UNLABELLED Radionuclide myocardial perfusion imaging (MPI) with single photon emission computed tomography (SPECT) has been widely used clinically as one of the major functional imaging modalities for patients with coronary artery disease (CAD) for decades. Ample evidence has supported the use of MPI as a useful and important tool in the diagnosis, risk stratification and treatment planning for CAD. Although popular in the United States, MPI has become the most frequently used imaging modality among all nuclear medicine tests in Taiwan. However, it should be acknowledged that MPI SPECT does have its limitations. These include false-positive results due to certain artifacts, false-negative due to balanced ischemia, complexity and adverse reaction arising from current pharmacological stressors, time consuming nature of the imaging procedure, no blood flow quantitation and relatively high radiation exposure. The purpose of this article was to review the recent trends in nuclear cardiology, including the utilization of positron emission tomography (PET) for MPI, new stressor, new SPECT camera with higher resolution and higher sensitivity, dynamic SPECT protocol for blood flow quantitation, new software of phase analysis for evaluation of LV dyssynchrony, and measures utilized for reducing radiation exposure of MPI. KEY WORDS Coronary artery disease • Myocardial flow reserve • Myocardial perfusion imaging • Phase analysis • PET • SPECT.

PET/MRI for evaluating subclinical inflammation of ulcerative colitis

To explore the utility of integrated positron emission tomography (PET) / magnetic resonance imaging (MRI) for evaluating subclinical inflammation in patients with ulcerative colitis (UC).

Search of Unknown Fever Focus Using PET in Critically Ill Children With Complicated Underlying Diseases.

Objectives: PET/CT with 18F-fluorodeoxyglucose can be used to image cellular metabolism and has been used for evaluating fever of unknown origin in adults. However, there are limited studies about the role of 18F-fluorodeoxyglucose PET/CT in evaluation of fever of unknown origin in critically ill children, especially those presenting with complicated underlying diseases under treatment. Here, we report our preliminary experience using 18F-fluorodeoxyglucose PET/CT in this specific group of patients. Design: Retrospective observational study. Setting: PICUs of a university hospital. Patients: Nineteen critically ill children (mean age, 5.7 yr old) with complicated underlying diseases requiring intensive care support underwent 18F-fluorodeoxyglucose PET/CT to evaluate fever of unknown origin. The median hospitalized stay was 34 days (range, 15–235 d) and fever of at least 7 days (mean, 21.6 d; range, 7–52 d). The PET scan was advocated after all routine microbiology, and conventional imaging showed negative or inconclusive results. Interventions: None. Measurements and Main Results: The 18F-fluorodeoxyglucose PET/CT findings (blinded to the final clinical diagnosis) were compared with final histopathology, culture, serology results, or follow-up imaging. A final diagnosis was made in 16 patients (84.2%). 18F-fluorodeoxyglucose PET/CT accurately localized the source of fever in 14 patients, confers to a sensitivity of 87.5% (14 of 16; 95% CI, 0.604–0.978). A false-positive scan in a patient led to subsequent unnecessary investigations. Two false-negative 18F-fluorodeoxyglucose PET/CT images were later attributed to relapse of underlying disease in the bone marrow and renal abscesses, respectively. In the other two patients where 18F-fluorodeoxyglucose PET/CT also showed negative findings, fever subsided shortly thereafter without treatment. Conclusions: Our preliminary experience suggests that 18F-fluorodeoxyglucose PET/CT may be clinically beneficial in evaluating fever of unknown origin in children with complicated underlying diseases mandating intensive support in ICUs if usual investigative methods are unsuccessful. Further large prospective studies are needed to validate these findings.

The relationship between serum fibrosis markers and restrictive ventricular filling in patients with heart failure with reduced ejection fraction: A technetium-99m radionuclide ventriculography study

Myocardial fibrosis leads to a restrictive diastolic filling pattern of the left ventricle which is associated with a poor prognosis in patients with heart failure. We investigated the relationship between cardiac fibrosis and restrictive filling pattern of the left ventricle measured by Tc99m left ventriculography in patients with chronic symptomatic heart failure. Serum cardiac extracellular matrix markers including type I and III aminoterminal propeptide of procollagen (PINP and PIIINP), matrix metalloproteinase-2,9 (MMP-2,9), and tissue inhibitor of MMP-1 (TIMP-1) were analyzed. Fifty-one (39 males) patients were enrolled. Their median age was 51.8 years, and median left ventricular ejection fraction was 31.9%. Time to peak filling rate of the left ventricle was significantly correlated with serum levels of the three cardiac extracellular matrix markers (TIMP-1, PIIINP, and MMP-2). The patients with a restrictive diastolic filling pattern of the left ventricle (time to peak filling rate = 154 ms) had significantly higher levels of these extracellular matrix markers. In receiver operating characteristic curve analysis, areas under the curve of PIIINP, TIMP-1, and MMP-2 were 0.758, 0.695, and 0.751 to predict the presence of a restrictive pattern. In C-statistics, all three cardiac extracellular matrix markers significantly increased the area under the curve after adding creatinine. In net reclassification improvement and integrated discrimination improvement models, PIIINP and MMP-2 significantly improved the predictive power of age, creatinine and brain natriuretic peptide. In conclusion, serum extracellular matrix markers are significantly correlated with restrictive diastolic filling pattern of the left ventricle in patients with heart failure.

Clinical Utility of FDG PET/CT in Patients with Autoimmune Pancreatitis: a Case-Control Study

Autoimmune pancreatitis (AIP) shares overlapping clinical features with pancreatic cancer (PC). Importantly, treatment of the two conditions is different. We investigated the clinical usefulness of 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in patients with suspected AIP before treatment. From September 2008 to July 2016, 53 patients with suspected AIP at National Taiwan University Hospital had PET/CT prior to therapy to exclude malignancy and evaluate the extent of inflammation. Their scans were compared with those from 61 PC patients. PET imaging features were analyzed using logistic regression. Significant differences in pancreatic tumor uptake morphology, maximum standardized uptake value, high-order primary tumor texture feature (i.e. high-gray level zone emphasis value), and numbers and location of extrapancreatic foci were found between AIP and PC. Using the prediction model, the area under curve of receiver-operator curve was 0.95 (P < 0.0001) with sensitivity, specificity, positive predictive, and negative predictive values of 90.6%, 84.0%, 87.9%, and 87.5% respectively, in differentiating AIP from PC. FDG PET/CT offers high sensitivity, albeit slightly lower specificity in differentiating AIP from PC. Nonetheless, additional systemic inflammatory foci detected by the whole body PET/CT help confirm diagnosis of AIP in these patients before initiating steroid therapy, especially when biopsy is inconclusive.

Increased heterogeneity of brain perfusion is an early marker of central nervous system involvement in antiphospholipid antibody carriers

Objective The non-criteria neuropsychiatric manifestations of antiphospholipid syndrome include headache, dizziness, vertigo, seizure, depression and psychosis. There were still no objective methods qualified to detect the early central nervous system involvement in non-criteria antiphospholipid syndrome. We evaluated the effectiveness of Tc-99m ECD SPECT in assessing circulatory insufficiency in the brains of patients with antiphospholipid antibodies and neuropsychiatric symptoms but without thromboembolism. Materials and methods Patients with a history of positive antiphospholipid antibodies and neuropsychiatric symptoms composed the case group; patients without antiphospholipid antibody served as the control group. Subjects with a history of thromboembolism or autoantibodies to extractable nuclear antigens were excluded. All patients received Tc-99m ECD SPECT studies and were classified by the number of positive antiphospholipid antibodies they carried. The heterogeneity of brain perfusion was defined as the coefficient of variation of the SPECT signals. Analysis of variance (ANOVA) was applied to evaluate the differences between the groups. Results Total 60 adult patients were included in this study. There were 54 patients in the case group and 6 patients in the control group. The mean age was 38.3 ± 11.5 years. There were 52 women and 8 men. There was no significant difference in the mean brain perfusion between groups (P = 0.69). However, Tc-99m ECD SPECT demonstrated significant heterogeneity of brain perfusion in relation to the number of antiphospholipid antibodies (P = 0.01). Conclusions This is the first study demonstrating that Tc-99m ECD SPECT can early detect the increased heterogeneity of brain circulation in non-criteria antiphospholipid antibody carriers.

14 Increased heterogeneity of brain perfusion is an early marker of central nervous system involvement in antiphospholipid antibody carriers

Background and Aims The non-criteria neuropsychiatric manifestations of antiphospholipid syndrome include headache, dizziness, vertigo, seizure, depression and psychosis. There was still no objective method qualified to detect the early central nervous system involvement in non-criteria antiphospholipid syndrome. We evaluated the effectiveness of Tc-99m ECD SPECT in assessing circulatory insufficiency in the brains of patients with antiphospholipid antibodies and neuropsychiatric symptoms but without thromboembolism. Methods Patients with a history of positive antiphospholipid antibodies and neuropsychiatric symptoms but without thromboembolism composed the case group; patients without antiphospholipid antibody served as the control group. Subjects with autoantibodies to extractable nuclear antigens were excluded from this study. All patients underwent Tc-99m ECD SPECT and were classified by the number of positive antiphospholipid antibodies they carried. The heterogeneity of brain perfusion was defined as the coefficient of variation. Analysis of variance (ANOVA) was used to evaluate the differences between groups. Results Total 60 adult patients were included in this study. There were 54 patients in the case group and 6 patients in the control group. The mean age was 38.3±11.5 years. There were 52 women and 8 men. There was no significant difference in mean brain perfusion between groups (p=0.69). However, Tc-99m ECD SPECT demonstrated significant heterogeneity of brain perfusion in relation to the number of antiphospholipid antibodies (p=0.01). Conclusions This is the first study to show that Tc-99m ECD SPECT can detect the increased heterogeneity of brain circulation in non-criteria antiphospholipid antibody carriers with neuropsychiatric manifestations.

Diagnostic and Prognostic Implications of Exercise Treadmill and Rest First-Pass Radionuclide Angiography in Patients With Pulmonary Hypertension

Purpose Pulmonary hypertension (PH) is characterized by abnormally increased pulmonary vascular pressure, leading to deteriorated right ventricular function and premature death. Pulmonary mean transit time (PMTT) and biventricular function response to exercise in first-pass radionuclide angiography (FP-RNA) may provide early detection and timely disease monitoring of PH. This study aimed to investigate the diagnostic and prognostic values of this imaging modality in PH patients. Methods Left and right ventricular ejection fraction (LVEF/RVEF) and PMTT at rest and immediately after exercise treadmill test were measured by FP-RNA in 77 consecutive patients with clinical presentations suggestive of PH (aged 46 ± 15 years, 33 men), mostly with symptoms of unexplained progressive dyspnea. These parameters, along with other clinical variables, were correlated with right-sided heart catheterization data and clinical outcomes. Results Fifty patients (64.9%) were diagnosed as having definite PH. Besides higher N-terminal pro–B-type natriuretic peptide levels, right atrial pressure, and pulmonary vascular resistance, PH patients had significantly longer PMTT, lower LVEF after exercise and rest, and lower poststress RVEF (all P < 0.05), compared with non-PH subjects. Moreover, PH patients exhibited stress-induced right ventricular dysfunction and stationary poststress PMTT. Poststress PMTT and echocardiography had comparable diagnostic utility (area under the curve, 0.80 vs 0.84, respectively). Eighteen patients died during a median follow-up period of 380 days. Failure of exercise treadmill test, lower peak heart rate response, and stress/rest LVEF ratio of less than 90% using exercise treadmill FP-RNA were independent predictors of mortality in PH patients. Conclusions Exercise treadmill and rest FP-RNA provided diagnostic value and had prognostic implications in patients with PH.