Pulmonary intravascular blood volume changes through the cardiac cycle in healthy volunteers studied by cardiovascular magnetic resonance measurements of arterial and venous flow

BACKGROUND: This study aims to present a novel method for using cardiovascular magnetic resonance (CMR) to non-invasively quantify the variation in pulmonary blood volume throughout the cardiac cycle in humans. METHODS: 10 healthy volunteers (7 males, 3 female, age range 21-32 years) were studied. The blood flow in the pulmonary artery and all pulmonary veins was quantified during free breathing using phase contrast velocity encoded CMR. The difference in flow between the pulmonary artery and the pulmonary veins was integrated to calculate the change in pulmonary blood volume throughout the cardiac cycle. RESULTS: The stroke volumes in the pulmonary artery and the sum of the pulmonary veins were (mean +/- SEM) 103 +/- 6 ml and 95 +/- 6 ml, respectively. The pulmonary blood volume variation (PBVV) was 48 +/- 5 ml, and the PBVV expressed as percent of the pulmonary artery stroke volume was 46 +/- 3%. The maximum increase in pulmonary blood volume occurred 310 +/- 12 ms after the R-wave from the ECG (32 +/- 2% of the cardiac cycle). PBVV did not correlate to change in cross-sectional area in the pulmonary artery (R2 = 0.03, p = 0.66). CONCLUSION: It is feasible to non-invasively quantify the change in pulmonary blood volume during the cardiac cycle in humans using CMR. The average pulmonary blood volume variation in healthy volunteers was approximately 50 ml and this was approximately 50% of the stroke volume. Further studies are needed to assess the utility of the pulmonary blood volume variation as a measure for identifying cardiac and pulmonary vascular disease

Head-to-head comparison of a 2-day myocardial perfusion gated SPECT protocol and cardiac magnetic resonance late gadolinium enhancement for the detection of myocardial infarction.

The aim was to determine the sensitivity and specificity of gated myocardial perfusion SPECT (MPS) with a technetium-labelled (Tc) perfusion tracer to detect myocardial infarction (MI) in a clinical population referred for assessment of stress-induced ischemia using late gadolinium enhancement cardiac magnetic resonance (CMR) as reference method

Quantification of left and right atrial kinetic energy using four-dimensional intracardiac magnetic resonance imaging flow measurements

Kinetic energy (KE) of atrial blood has been postulated as a possible contributor to ventricular filling. Therefore, we aimed to quantify the left and right atrial blood KE using cardiac magnetic resonance (CMR). Fifteen healthy volunteers underwent CMR at 3T, including a four-dimensional phase contrast flow sequence. Mean left atrial (LA) KE was lower than right atrial (RA) KE (1.1±0.1 mJ vs 1.7±0.1 mJ, P<0.01). Three KE peaks were seen in both atria; one in ventricular systole, one during early ventricular diastole, and one during atrial contraction. The systolic LA peak was significantly smaller than the RA peak (P<0.001), and the early diastolic LA peak was larger than the RA peak (P<0.05). Rotational flow contained 46 ± 7% of total KE, and conserved energy better than non-rotational flow did. The KE increase in early diastole was higher in the LA (P<0.001). Systolic KE correlated with the combination of atrial volume and systolic velocity of the atrioventricular plane displacement (R2=0.57 for LA and R2=0.64 for RA). Early diastolic KE of the LA correlated with LV mass (R2=0.28), however no such correlation was found in the right heart. This suggests that LA KE increases during early ventricular diastole due to LV elastic recoil, indicating that LV filling is dependent on diastolic suction. RV relaxation does not seem to contribute to atrial KE. Instead, atrial KE generated during ventricular systole may be conserved in a hydraulic "flywheel" and transferred to the RV through helical flow, which may contribute to RV filling

Att vara i könsminoritet på sin utbildning - En kvantitativ studie av hur underrepresenterade kvinnor och män upplever sin situation.

Denna studie undersöker upplevelsen av att vara i könsminoritet på utbildning. Syftet var att studera skillnader i att vara kvinna på en mansdominerad utbildning eller man på en kvinnodominerad. Skillnader i nöjdhet med utbildningen, välmående, samt avhoppstankar var en central utgångspunkt. Variablerna likhet och tillhörighet, sociala identitetshot, stöd och barriärer, upplevd kompetens, samt könsnormer undersöktes i syfte att finna prediktorer för avhoppstankar. Minoritetsgrupperna har även ställts i kontrast till de studenter som befinner sig i könsmajoritet. Deltagarna (N=281) i studien var nästan uteslutande förstaterminsstudenter vid två könstypiska utbildningar vid Lunds Universitet, socionomutbildningen och maskinteknologiska utbildningen. Både studenter i könsminoritet och könsmajoritet fick besvara självskattningsfrågor i en enkät som behandlade ovanstående variabler. Det huvudsakliga resultatet visade, till skillnad från tidigare amerikansk forskning, att män på den kvinnodominerade utbildningen funderade mer på att hoppa av än sina kvinnliga klasskamrater medan kvinnorna på den mansdominerade utbildningen inte hade mer avhoppstankar än sina manliga klasskamrater