Spatial filtering of a projection printer, using partially coherent light

This investigation applied the technique of spatial filtering to a projection printer utilizing partially coherent illumination. The affect of filtering on image quality parameters such as resolution, edge gradient and MTF were determined for a black and white film. Edge gradient analysis was used to derive MTF data from sampled edges. A source diameter of 3 mm and spatial filter diameters of .6, 2.2, and 3.0 mm were used. Spatial filtering was seen to have a drastic affect on edge gradient and MTF. Increasing the filter diameter resulted in a decrease of cutoff frequency of the system. Spatial filtering had the affect of boosting low frequency modulation by up to 30 percent. Subjectively, however, changes could not be detected, indicating that the alterations made to the system are not significant to be detected visually. Resolution was found to fluctuate only 15 percent between the application of each filter. Despite gross changes in other imaging characteristics, resolution remained nearly unchanged, indicating that resolution is a poor discriptor of image quality

Transcatheter aortic valve replacement and standard therapy in inoperable patients with aortic stenosis and low EF.

OBJECTIVES: The aims of this study were to evaluate the effect of left ventricular (LV) dysfunction on clinical outcomes after transcatheter aortic valve replacement (TAVR) and standard therapy for severe aortic stenosis (AS) and to assess LV ejection fraction (LVEF) recovery and its impact on subsequent clinical outcomes. METHODS: Cohort B of the Placement of AoRtic TraNscathetER Valves trial randomised 342 inoperable patients with severe AS to TAVR or standard therapy. We defined LV dysfunction as an LVEF <50% and LVEF improvement as an absolute increase in LVEF =10% at 30 days. RESULTS: Baseline LV dysfunction did not affect survival after TAVR but was associated with increased cardiac mortality at 1 year with standard therapy (59.3% vs 45.8% with normal LVEF; HR=1.71 (95% CI 1.08 to 2.71); p=0.02). In those with LV dysfunction, LVEF improvement occurred in 48.7% and 30.4% of TAVR and standard therapy patients, respectively (p=0.08), and was independently predicted by relative wall thickness and receipt of TAVR. LVEF improvement with standard therapy portended reduced all-cause mortality at 1 year (28.6% vs 65.6% without LVEF improvement; HR=0.32 (95% CI 0.11 to 0.93); p=0.03) but not at 2 years. CONCLUSIONS: In inoperable patients with severe AS, mild-to-moderate LV dysfunction is associated with higher cardiac mortality with standard therapy but not TAVR. A subset of patients undergoing standard therapy with LV dysfunction demonstrates LVEF improvement and favourable 1-year but not 2-year survival. TAVR improves survival and should be considered the standard of care for inoperable patients with AS and LVEF >20%

Association between early left ventricular ejection fraction improvement after transcatheter aortic valve replacement and 5-year clinical outcomes

Importance In patients with severe aortic stenosis and left ventricular ejection fraction (LVEF) less than 50%, early LVEF improvement after transcatheter aortic valve replacement (TAVR) is associated with improved 1-year mortality; however, its association with long-term clinical outcomes is not known. Objective To examine the association between early LVEF improvement after TAVR and 5-year outcomes. Design, Setting, and Participants This cohort study analyzed patients enrolled in the Placement of Aortic Transcatheter Valves (PARTNER) 1, 2, and S3 trials and registries between July 2007 and April 2015. High- and intermediate-risk patients with baseline LVEF less than 50% who underwent transfemoral TAVR were included in the current study. Data were analyzed from August 2020 to May 2021. Exposures Early LVEF improvement, defined as increase of 10 percentage points or more at 30 days and also as a continuous variable (ΔLVEF between baseline and 30 days). Main Outcomes and Measures All-cause death at 5 years. Results Among 659 included patients with LVEF less than 50%, 468 (71.0%) were male, and the mean (SD) age was 82.4 (7.7) years. LVEF improvement within 30 days following transfemoral TAVR occurred in 216 patients (32.8%) (mean [SD] ΔLVEF, 16.4 [5.7%]). Prior myocardial infarction, diabetes, cancer, higher baseline LVEF, larger left ventricular end-diastolic diameter, and larger aortic valve area were independently associated with lower likelihood of LVEF improvement. Patients with vs without early LVEF improvement after TAVR had lower 5-year all-cause death (102 [50.0%; 95% CI, 43.3-57.1] vs 246 [58.4%; 95% CI, 53.6-63.2]; P = .04) and cardiac death (52 [29.5%; 95% CI, 23.2-37.1] vs 135 [38.1%; 95% CI, 33.1-43.6]; P = .05). In multivariable analyses, early improvement in LVEF (modeled as a continuous variable) was associated with lower 5-year all-cause death (adjusted hazard ratio per 5% increase in LVEF, 0.94 [95% CI, 0.88-1.00]; P = .04) and cardiac death (adjusted hazard ratio per 5% increase in LVEF, 0.90 [95% CI, 0.82-0.98]; P = .02) after TAVR. Restricted cubic spline analysis demonstrated a visual inflection point at ΔLVEF of 10% beyond which there was a steep decline in all-cause mortality with increasing degree of LVEF improvement. There were no statistically significant differences in rehospitalization, New York Heart Association functional class, or Kansas City Cardiomyopathy Questionnaire Overall Summary score at 5 years in patients with vs without early LVEF improvement. In subgroup analysis, the association between early LVEF improvement and 5-year all-cause death was consistent regardless of the presence or absence of coronary artery disease or prior myocardial infarction. Conclusions and Relevance In patients with severe aortic stenosis and LVEF less than 50%, 1 in 3 experience LVEF improvement within 1 month after TAVR. Early LVEF improvement is associated with lower 5-year all-cause and cardiac death