Objective
To determine whether the recently introduced Bayesian penalized likelihood PET reconstruction (Q.Clear) increases the visual conspicuity and SUV
max
of small pulmonary nodules near the PET ...resolution limit, relative to ordered subset expectation maximization (OS-EM).
Methods
In this institutional review board-approved and HIPAA-compliant study, 29 FDG PET/CT scans performed on a five-ring GE Discovery IQ were retrospectively selected for pulmonary nodules described in the radiologist’s report as “too small to characterize”, or small lung nodules in patients at high risk for lung cancer. Thirty-two pulmonary nodules were assessed, with mean CT diameter of 8 mm (range 2–18). PET images were reconstructed with OS-EM and Q.Clear with noise penalty strength
β
values of 150, 250, and 350. Lesion visual conspicuity was scored by three readers on a 3-point scale, and lesion SUV
max
and background liver and blood pool SUV
mean
and SUV
stdev
were recorded. Comparison was made by linear mixed model with modified Bonferroni post hoc testing; significance cutoff was
p
< 0.05.
Results
Q.Clear improved lesion visual conspicuity compared to OS-EM at
β
= 150 (
p
< 0.01), but not 250 or 350. Lesion SUV
max
was increased compared to OS-EM at
β
= 150 and 250 (
p
< 0.01), but not 350.
Conclusion
In a cohort of small pulmonary nodules with size near an 8 mm PET full-width half maximum, Q.Clear significantly increased lesion visual conspicuity and SUV
max
compared to our standard non- time-of-flight OS-EM reconstruction, but only with low noise penalization. Q.Clear with
β
= 150 may be advantageous when evaluation of small pulmonary nodules is of primary concern.
Inflammatory disorders of the cardiovascular system can affect the myocardium, pericardium, or vessel walls. Patients with myocardial and pericardial disease may present with chest pain, ...palpitations, and shortness of breath, symptoms resembling myocardial ischemia or infarction. The manifestations of vasculitis may include fever, weight loss, and fatigue, mimicking infectious or malignant processes. Because of the difficulty of differentiating these disease processes, patients frequently undergo multiple diagnostic examinations before obtaining a final diagnosis of myocarditis, pericarditis, or vasculitis. Computed tomography (CT) and magnetic resonance imaging play important roles in the assessment of structural abnormalities of the cardiovascular system, and combined positron emission tomography (PET) and CT may depict inflammatory processes before structural changes occur. Familiarity with the PET/CT appearances of inflammatory processes in the myocardium, pericardium, and vessels is important for accurate and prompt diagnosis.
Objectives The study objectives were to test the hypotheses that ischemia during stress testing has prognostic value and identifies those patients with coronary artery disease (CAD) with left ...ventricular (LV) dysfunction who derive the greatest benefit from coronary artery bypass grafting (CABG) compared with medical therapy. Background The clinical significance of stress-induced ischemia in patients with CAD and moderately to severely reduced LV ejection fraction (EF) is largely unknown. Methods The STICH (Surgical Treatment for IsChemic Heart Failure) trial randomized patients with CAD and EF ≤35% to CABG or medical therapy. In the current study, we assessed the outcomes of those STICH patients who underwent a radionuclide (RN) stress test or a dobutamine stress echocardiogram (DSE). A test was considered positive for ischemia by RN testing if the summed difference score (difference in tracer activity between stress and rest) was ≥4 or if ≥2 of 16 segments were ischemic during DSE. Clinical endpoints were assessed by intention to treat during a median follow-up of 56 months. Results Of the 399 study patients (51 women, mean EF 26 ± 8%), 197 were randomized to CABG and 202 were randomized to medical therapy. Myocardial ischemia was induced during stress testing in 256 patients (64% of the study population). Patients with and without ischemia were similar in age, multivessel CAD, previous myocardial infarction, LV EF, LV volumes, and treatment allocation (all p = NS). There was no difference between patients with and without ischemia in all-cause mortality (hazard ratio: 1.08; 95% confidence interval: 0.77 to 1.50; p = 0.66), cardiovascular mortality, or all-cause mortality plus cardiovascular hospitalization. There was no interaction between ischemia and treatment for any clinical endpoint. Conclusions In CAD with severe LV dysfunction, inducible myocardial ischemia does not identify patients with worse prognosis or those with greater benefit from CABG over optimal medical therapy. (Comparison of Surgical and Medical Treatment for Congestive Heart Failure and Coronary Artery Disease STICH; NCT00023595 )
Dengue is considered a serious public health problem in many tropical regions of the world including Brazil. At the moment, there is no viable alternative to reduce dengue infections other than ...controlling the insect vector, Aedes aegypti Linnaeus. In the continuing search for new sources of chemicals targeted at vector control, natural products are a promising alternative to synthetic pesticides. In our work, we investigated the toxicity of a bioactive compound extracted from the red alga Laurencia dendroidea J. Agardh. The initial results demonstrated that crude extracts, at a concentration of 5 ppm, caused pronounced mortality of second instar A. aegypti larvae. Two molecules, identified as (-)-elatol and (+)-obtusol were subsequently isolated from crude extract and further evaluated. Assays with (-)-elatol showed moderate larvicidal activity, whereas (+)-obtusol presented higher toxic activity than (-)-elatol, with a LC50 value of 3.5 ppm. Histological analysis of the larvae exposed to (+)-obtusol revealed damage to the intestinal epithelium. Moreover, (+)-obtusol-treated larvae incubated with 2 µM CM-H₂DCFDA showed the presence of reactive oxygen species, leading us to suggest that epithelial damage might be related to redox imbalance. These results demonstrate the potential of (+)-obtusol as a larvicide for use against A. aegypti and the possible mode of action of this compound.
ABSTRACT The aim of this study was to evaluate the effects of cropping systems (single and twin-rows) and N fertilizer rate in the second top-dressing on the agronomic performance and relative ...economic returns of maize. Recently, studies have been conducted to evaluate the effects of different plant arrangements and spacings on maize yield, aiming to increase the grain yield without increasing the crop production costs (Lacerda et al., 2015). The aim of this study was to evaluate the effects of cropping systems (single and twin-rows) and N fertilizer rate in the second top-dressing, on the agronomic performance and relative economic returns for maize. In the single-row system, the row spacing was 0.45 m, whilst in the twin-row system it was 0.45 x 0.90 m. The subplots were composed of six N fertilizer rate, applied in in the second top-dressing during the V8 phenological stage (eight fully developed leaves) in maize (12/21/2015): 0, 14, 28, 56, and 70 kg ha-1 of N. The first application of N in the top-dressing (rate of 140 kg ha-1 of N) was carried out during the V4 phenological stage (four fully developed leaves) in all treatments (12/08/2015) (Cantarella et al., 1997). During the stage of physiological maturity of maize (R6), the final height of the plants (m), height of insertion of the ear (m), stem diameter (mm), number of rows and grains per ear, mass of 1000 grains, and grain yield (kg ha-1) were evaluated.
Phase analysis of gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is an evolving technique for measuring LV mechanical dyssynchrony. Since its inception in ...2005, it has undergone considerable technical development and clinical evaluation. This article reviews the background, the technical and clinical characteristics, and evolving clinical applications of phase analysis of gated SPECT MPI in patients requiring cardiac resynchronization therapy or implantable cardioverter defibrillator therapy and in assessing LV diastolic dyssynchrony.
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