ADAPTIVE REGULARIZATION USING B-SPLINES FOR GATED DYNAMIC CARDIAC SPECT

2007 ◽  
Author(s):  
Yongyi Yang ◽  
Mingwu Jin
Keyword(s):  
Cardiac Spect ◽  
Adaptive Regularization ◽  
B Splines

B-splines on sparse grids for surrogates in uncertainty quantification

2021 ◽  
Vol 209 ◽  
pp. 107430
Author(s):  
Michael F. Rehme ◽  
Fabian Franzelin ◽  
Dirk Pflüger
Keyword(s):  
Uncertainty Quantification ◽  
Sparse Grids ◽  
B Splines

Regional cardiac uptake of 99-Tc-DPD is a novel powerful and independent prognostic marker in cardiac ATTR wild type amyloidosis

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
P Milani ◽  
G Cavenaghi ◽  
L Obici ◽  
R Mussinelli ◽  
C Klersy ◽  
...  
Keyword(s):  
Prognostic Value ◽  
Cox Regression ◽  
Expectation Maximization Algorithm ◽  
Linear Increase ◽  
Whole Body ◽  
Wall Region ◽  
Cardiac Spect ◽  
Risk Of Death ◽  
Cardiac Wall

Abstract Background Skeletal scintigraphy with bone tracers is a key tool for cardiac ATTR diagnosis. However its prognostic value has not been systematically assessed. Purpose We evaluated the prognostic relevance of a quantitative method to assess regional 99mTc-DPD uptake by SPECT in the heart of ATTRwt patients. Methods All ATTRwt patients (n=229) undergoing clinical assessment and bone scintigraphy at our center (from 2012 to 2019) were enrolled. Theyreceived approximately 700 MBq of 99mTc-DPD. Planar whole body acquisition 10' after the injection followed by cardiac SPECT after 3 hours were performed. SPECT data were reconstructed into 64x64 matrices with an ordered-subset expectation maximization algorithm. For each wall region and for the apex, a circular region of interest (ROI, 20 pixels) was manually drawn and a value equating to the number of counts contained in the ROI was obtained. Partial correlation of ln-transformed ROI and biomarkers was retrieved from a multivariable regression model, while controlling for each cardiac wall region. Multivariable Cox regression was used to assess the prognostic role of lnROI while adjusting for wall region, NT-proBNP, cTnI and eGFR. Hazard ratios and 95% confidence intervals (HR, 95% CI) were computed. The Harrell's c statistic was reported for model discrimination. The interaction of biomarker and regional wall on survival was assessed; also, to account for intra-subject correlation of measures, within subject robust standard errors were computed. Results Median follow-up was 21 months (IQR 11, 40) and 39 (17%) patients died. Median age was 76 years (IQR, 72–80), NT-proBNP 2944 ng/L (IQR, 1815–5319), cTnI 0.095 ng/L (IQR, 0.062–0.144) and eGFR 62 mL/min (IQR, 51–77). ROI did not correlate with any of NT-proBNP, eGFR, age, cTnI or mLVWT (R<1% in all cases). All analyses were adjusted for cardiac wall. At the multivariable Cox regression (Harrell's c=0.75), there was a linear increase in the risk of death associated with lnROI (HR 2.14, P=0.014), which was independent of cardiac wall region, NTproBNP, cTnI and eGFR. Only cTnI maintained a significant prognostic value. The association of lnROI and mortality was not modified by the site of measurement test for interaction with cardiac wall p=0.818). At the predefined subgroup analysis, the risk of death was similar for all walls; we computed the optimal cut-off for 12 months survival at the apex (a region usually lately involved) to 4193 (AUC: 0.68, sensitivity 80%, specificity 68%). At the multivariable Cox regression (Harrell's c 0.76), apex ROI>4193 was an independent predictor of death (HR 3.60, 95% CI 1.45–8.93, p=0.006) and outperformed all the biomarkers tested. Conclusions Quantitative assessment of ROI uptake at cardiac SPECT is a powerful predictor of survival in ATTRwt patients, independent of and outperforming the other known prognostic factors. This observation warrants validation with prolonged follow-up and in independent patient series. Funding Acknowledgement Type of funding source: None

scholarly journals Quality and utility of [123I]I-metaiodobenzylguanidine cardiac SPECT imaging in nondiabetic postinfarction heart failure patients qualified for implantable cardioverter defibrillator

2021 ◽  
Author(s):  
Anna Teresińska ◽  
Olgierd Woźniak ◽  
Aleksander Maciąg ◽  
Jacek Wnuk ◽  
Jarosław Jezierski ◽  
...  
Keyword(s):  
Heart Failure ◽  
Implantable Cardioverter Defibrillator ◽  
Left Lung ◽  
Spect Imaging ◽  
Cardiac Innervation ◽  
Cardiac Spect ◽  
Cardioverter Defibrillator ◽  
Planar Images ◽  
Spect Images

Abstract Objective Impaired cardiac adrenergic activity has been demonstrated in heart failure (HF) and in diabetes mellitus (DM). [123I]I-metaiodobenzylguanidine (MIBG) enables assessment of the cardiac adrenergic nervous system. Tomographic imaging of the heart is expected to be superior to planar imaging. This study aimed to determine the quality and utility of MIBG SPECT in the assessment of cardiac innervation in postinfarction HF patients without DM, qualified for implantable cardioverter defibrillator (ICD) in primary prevention of sudden cardiac death. Methods Consecutive patients receiving an ICD on the basis of contemporary guidelines were prospectively included. Planar MIBG studies were followed by SPECT. The essential analysis was based on visual assessment of the quality of SPECT images (“high”, “low” or “unacceptable”). The variables used in the further analysis were late summed defect score for SPECT images and heart-to-mediastinum rate for planar images. MIBG images were assessed independently by two experienced readers. Results Fifty postinfarction nondiabetic HF subjects were enrolled. In 13 patients (26%), the assessment of SPECT studies was impossible. In addition, in 13 of 37 patients who underwent semiquantitative SPECT evaluation, the assessment was equivocal. Altogether, in 26/50 patients (52%, 95% confidence interval 38–65%), the quality of SPECT images was unacceptable or low and was limited by low MIBG cardiac uptake and by comparatively high, interfering MIBG uptake in the neighboring structures (primarily, in the lungs). Conclusions The utility of MIBG SPECT imaging, at least with conventional imaging protocols, in the qualification of postinfarction HF patients for ICD, is limited. In approximately half of the postinfarction HF patients, SPECT assessment of cardiac innervation can be impossible or equivocal, even without additional damage from diabetic cardiac neuropathy. The criteria predisposing the patient to good-quality MIBG SPECT are: high values of LVEF from the range characterizing the patients qualified to ICD (i.e., close to 35%) and left lung uptake intensity in planar images comparable to or lower than heart uptake.

scholarly journals Towards B-Spline Atomic Structure Calculations

Atoms ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 50
Author(s):  
Charlotte Froese Fischer
Keyword(s):  
Atomic Structure ◽  
Bound States ◽  
Virial Theorem ◽  
B Spline ◽  
B Splines ◽  
Self Consistent ◽  
History Of ◽  
Consistent Method ◽  
Atomic Structure Calculations ◽  
Structure Calculations

The paper reviews the history of B-spline methods for atomic structure calculations for bound states. It highlights various aspects of the variational method, particularly with regard to the orthogonality requirements, the iterative self-consistent method, the eigenvalue problem, and the related sphf, dbsr-hf, and spmchf programs. B-splines facilitate the mapping of solutions from one grid to another. The following paper describes a two-stage approach where the goal of the first stage is to determine parameters of the problem, such as the range and approximate values of the orbitals, after which the level of accuracy is raised. Once convergence has been achieved the Virial Theorem, which is evaluated as a check for accuracy. For exact solutions, the V/T ratio for a non-relativistic calculation is −2.

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