1,721,000 research outputs found
Stress-induced alteration of left ventricular eccentricity: An additional marker of multivessel CAD
No full textBackgroundAbnormal left ventricular (LV) eccentricity index (EI) is a marker of adverse cardiac remodeling. However, the interaction between stress-induced alterations of EI and major cardiac parameters has not been explored. We sought to evaluate the relationship between LV EI and coronary artery disease (CAD) burden in patients submitted to myocardial perfusion imaging (MPI).Methods and resultsThree-hundred and forty-three patients underwent MPI and coronary angiography. LV ejection fraction (EF) and EI were computed from gated stress images as measures of stress-induced functional impairment.One-hundred and thirty-six (40%), 122 (35%), and 85 (25%) patients had normal coronary arteries, single-vessel CAD, and multivessel CAD, respectively. Post-stress EI was lower in patients with multivessel CAD than in those with normal coronary arteries and single-vessel CAD (P=0.001). This relationship was confirmed only in patients undergoing exercise stress test, where a lower post-stress EI predicted the presence of multivessel CAD (P=0.039).ConclusionsPost-stress alterations of LV EI on MPI may unmask the presence of multivessel CAD
GENDER DIFFERENCES IN REFERRAL TRENDS AND CLINICAL CHARACTERISTICS IN EVALUATION OF STABLE CORONARY ARTERY DISEASE (CAD) BY MYOCARDIAL SCINTIGRAPHY:A 20-YEAR ANALYSIS FROM A TERTIARY REFERRAL CENTER
No full textBackground
There are gender differences in management of stable CAD, with evidence of delayed diagnosis in women. Differences in referral patterns and clinical risk of patients can impact outcomes. We compared differences in baseline risk and use of myocardial scintigraphy among male and female patients with suspected CAD in a tertiary center in Italy, over 20 years.
Methods
This is a cross-sectional observational study of 20,953 patients (31% women, mean age 66.8 y) who were evaluated across 5 yearly intervals from 2000 to 2020. Temporal trends in risk factors and test results were compared between men and women.
Results
Men were more likely to be referred, however there was a steady increase in number of women referred for evaluation. Among women, there was a significant increase in prevalence of hypertension, but no change in smoking or diabetes. Over time, women were noted to have significant decrease in presence of ischemic myocardium at risk, identified by semi-quantitative scores including SRS, SSS, SDS at rest and increase in Ejection Fraction, compared to men. (p<0.05)
Conclusion
There are gender differences in proportions and clinical risk of patients referred for stress testing. Trends suggest a substantial change in risk of inducible myocardial ischemia, likely related to better sensitivity of nuclear cameras vs differential risk assessment in women. Our findings are relevant to understanding gender differences in risk stratification and diagnostic accuracy in CAD, and its effect on outcomes
Direct Parametric Maps Estimation from Dynamic PET Data: An Iterated Conditional Modes Approach
Full text linkWe propose and test a novel approach for direct parametric image reconstruction of dynamic PET data. We present a theoretical description of the problem of PET direct parametric maps estimation as an inference problem, from a probabilistic point of view, and we derive a simple iterative algorithm, based on the Iterated Conditional Mode (ICM) framework, which exploits the simplicity of a two-step optimization and the efficiency of an analytic method for estimating kinetic parameters from a nonlinear compartmental model. The resulting method is general enough to be flexible to an arbitrary choice of the kinetic model, and unlike many other solutions, it is capable to deal with nonlinear compartmental models without the need for linearization. We tested its performance on a two-tissue compartment model, including an analytical solution to the kinetic parameters evaluation, based on an auxiliary parameter set, with the aim of reducing computation errors and approximations. The new method is tested on simulated and clinical data. Simulation analysis led to the conclusion that the proposed algorithm gives a good estimation of the kinetic parameters in any noise condition. Furthermore, the application of the proposed method to clinical data gave promising results for further studies
Cardiorenal scintigraphy with tetrofosmin in the evaluation of cardiorenal disease
No full textObjectives: Renal function is an established predictor of cardiovascular prognosis and subclinical stages of cardiorenal pathology are increasingly investigated. To study myocardial perfusion and renal function simultaneously, we investigated the feasibility of a combined single cardiorenal scintigraphy using Tetrofosmin.
Methods: Twenty-three patients scheduled for double-day Gated SPECT gave their informed consent for a dynamic renal scintigraphy after the injection of 370 MBq of Tetrofosmin in the rest study (23 pts) and during adenosine infusion (15 pts) and for a DTPA study (74 MBq) after one week (21 pts). Kidney images and renograms were obtained. Renal uptake index (UI) as percentage of the injected dose and separate renal uptake (SRU) as the percentage contribution of each kidney to total renal uptake were calculated.
Results: Compared with DTPA, Tetrofosmin showed better kidney images and curves with a higher UI (p<0.001) and comparable SRU. Tetrofosmin UI significantly correlated with DTPA UI (p<0.0001), serum creatinine (p=0.02), left ventricular mass index (p<0.01) and the Doppler index of renal vascular resistances (p<0.01); separate kidney functions evaluated with either tracer (SRU) were closely related to each other (p<0.001). In the patients who underwent the test, adenosine induced a significant decrease in renal Tetrofosmin UI (p<0.005).
Conclusions: The data suggest that 1) cardiorenal scintigraphy with Tetrofosmin is feasible at a low cost in a single-shot study; 2) after appropriate validation it could allow functional renal evaluation in patients referred for cardiac SPECT; 3) the information could be relevant in terms of cardiovascular risk and prognosis
Using SUV as a guide to18F-FDG dose reduction
No full textThis article explores how one can lower the injected18F-FDG dose while maintaining validity in comparing standardized uptake values (SUVs) between studies. Variations of the SUV within each lesion were examined at different acquisition times. Methods: Our protocol was approved by either the Human Investigation Committee or the Institutional Review Board. All 120 PET datasets were acquired continuously for 180 s per bed position in list mode and were reconstructed to obtain 30-, 60-, 90-, 120-, 150-, and 180-s-per-bed-position PET images with registration to a single set of nondiagnostic CT images. Qualitative assessment of the images was performed separately for correlation. The SUV measurements of each lesion were computed and normalized to the 180-s acquisition values to create a stabilization factor. These stabilization factors were used to demonstrate a predictable trend of stabilization over time. The variances of the stabilization factors over the entire dataset, composed of several tumor types over a range of sizes, were compared for each time point with the corresponding 150-s time point using a 2-sided F test, which has similar values to the 180-s time point. Results: The variance of the data decreased with increasing acquisition time and with increasing dose but leveled off for sufficiently long acquisitions. Conclusion: Through the statistical analysis of SUVs for increasing acquisition times and visual evaluation of the plots, we developed and hereby propose an algorithm that can be used to seek the maximum reduction in administered18F-FDG dose while preserving the validity of SUV comparisons
Effect of prolonged fasting and low molecular weight heparin or warfarin therapies on 2-deoxy-2-[18F]-fluoro-D-glucose PET cardiac uptake
No full textBackground: Whether anticoagulants other than unfractionated heparin are able to suppress cardiac PET uptake of 2-deoxy-2-[18F]-fluoro-D-glucose (18F-FDG) is unknown. Methods: One-hundred-seventy-four patients without history and clinical evidence of cardiac dysfunction and/or coronary heart disease underwent a 18F-FDG PET/CT study. All patients were studied with a >12-hours fasting and divided into 2 groups: group-1 without anticoagulant therapy (n:75); group-2 patients on low molecular weight heparin (n:60) or warfarin therapy (n:39). Cardiac 18F-FDG uptake was estimated qualitatively using a 4-point scale and semiquantitatively as total LV glycolysis (LVG) and metabolic volume (MV), drawing isocontour volume of interest (VOI) including the whole LV. Results: Qualitatively, LV 18-FDG uptake was scored 0 or 1, indicating a good suppression, in 10/75 (13%) patients of group-1 and 77/99 (78%) of group-2 (p < .001). Semiquantitatively, patients of group-1 showed higher values of 18-FDG uptake than patients of group-2, assessed as LVG (802,649 ± 468,442 vs 198,989 ± 261,439, p < .0001) or MV (219 ± 77 vs 57 ± 48 cm3, p < .0001). Subanalysis for anticoagulant drugs showed similar results. Conclusions: Prolonged fasting combined to anticoagulants other than unfractionated heparin is able to minimize glucose cardiac metabolism. Our data confirm previous observation on the possibility to influence the metabolic pattern of the heart before the PET scan and broadens the spectrum of pharmacological options
Prognostic Role of Dynamic CZT Imaging in CAD Patients: Interaction Between Absolute Flow and CAD Burden
No full textImpact of appropriateness in clinical practice: data from a single-centre nuclear cardiology laboratory
No full textAims: To verify the level of appropriateness of referral to our nuclear cardiology laboratory for stress myocardial perfusion imaging (MPI) and explore the correlation between test appropriateness patterns and ischaemia.
Methods and results: In 1870 consecutive patients (mean age 73 ± 12 years; 33% female) undergoing MPI, the level of imaging test appropriateness was evaluated according to the 2023 Appropriate Use Criteria (AUC) and the current European Society of Cardiology (ESC) guidelines for the management of chronic coronary syndromes. The evidence of moderate-to-severe ischaemia (i.e. summed difference score >7) was recorded. According to the AUC criteria, the MPI of 1638 (88%), 130 (7%), and 102 (5%) patients could be classified as ‘appropriate’, ‘inappropriate’, and ‘uncertain’, respectively. Similarly, in 1685 (90%) patients, the referral to MPI was adherent to ESC guidelines, while in 185 (10%), it was not. The majority of appropriate MPI tests showed the presence of moderate-to-severe ischaemia (55%), while only a limited number (10%; P < 0.05) of MPI tests with uncertain clinical appropriateness or clearly inappropriate indications did not. In patients managed adherently to ESC guidelines, invasive coronary angiography more frequently showed obstructive coronary artery disease (CAD) (93 vs. 47%, P < 0.001) and led to coronary revascularization (65 vs. 23%, P < 0.001) compared with patients managed non-adherently.
Conclusion: In a single-centre, single-national, single-modality population, the current rate of appropriate MPI tests is high. Appropriate referrals are associated with a higher probability of moderate-to-severe ischaemia and better downstream resource utilization than inappropriate ones
The Role of Scintigraphy with Bone Radiotracers in Cardiac Amyloidosis
No full text: Cardiac amyloidosis (CA) is caused by the myocardial deposition of misfolded proteins, either amyloid transthyretin (ATTR) or immunoglobulin light chains (AL). The paradigm of this condition has transformed, since CA is increasingly recognized as a relatively prevalent cause of heart failure. Cardiac scintigraphy with bone tracers is the unique noninvasive technique able to confirm CA without performing tissue biopsy or advanced imaging tests. A moderate-to-intense myocardial uptake (Perugini grade ≥2) associated with the absence of a monoclonal component is greater than 99% specific for ATTR-CA, while AL-CA confirmation requires tissue biopsy
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