The effect of cigarette smoking on the semen parameters of infertile men.

INTRODUCTION: 36.9% of men worldwide use tobacco. Previous studies suggest a negative effect of cigarette smoking on semen quality, but the results are contradictory. We have studied the effects of smoking on the semen characteristics such as sperm concentration, semen volume, sperm motility, sperm vitality and sperm morphology in a large group of infertile men. METHODS: This retrospective study was conducted on a total of 5146 infertile men with at least one year of idiopathic infertility, who admitted to the Centre for Reproductive medicine (CRG) at the Brussels University Hospital, Belgium between 2010 and 2017. The smokers were classified as mild (1-10 cigarettes/d), moderate (11-20 cigarettes/d) or heavy smokers (> 20 cigarettes/d). Semen analysis was performed for all patients. Statistical analysis was performed using the R software package and t-test or Mann-Whitney U tests were used, group comparisons were performed using ANOVA, ANCOVA or Kruskal-Wallis tests as appropriate. A p-value <0.05 was considered as statistically significant. RESULTS: Comparing the semen parameters in the two global groups showed that smoking had a significant decrease in semen volume (p=0.04074) and sperm concentration (p=0.029). ANOVA testing on the different smoking groups versus non-smoking group showed a significant decrease in sperm concentration (p=0.0364). After adjusting for the confounders, age and testosterone, ANCOVA testing showed significant effect on the sperm concentration (p=0.03871) in smokers versus non-smokers. No significant correlation was detected between the other semen characteristics. CONCLUSION: We concluded that smoking had a significant and independent effect on the sperm concentration in a semen analysis. Other parameters, like semen volume, sperm motility, sperm vitality and sperm morphology were not influenced by smoking.

Quantitative Effect of Metal Artefact Reduction on CT-based attenuation correction in FDG PET/CT in patients with hip prosthesis.

BACKGROUND: Metal artefact reduction (MAR) techniques still are in limited use in positron emission tomography/computed tomography (PET/CT). This study aimed to investigate the effect of Smart MAR on quantitative PET analysis in the vicinity of hip prostheses. MATERIALS AND METHODS: Activities were measured on PET/CT images in 6 sources with tenfold activity concentration contrast to background, attached to the head, neck and the major trochanter of a human cadaveric femur, and in the same sources in similar locations after a hip prosthesis (titanium cup, ceramic head, chrome-cobalt stem) had been inserted into the femur. Measurements were compared between PET attenuation corrected using either conventional or MAR CT. In 38 patients harbouring 49 hip prostheses, standardized uptake values (SUV) in 6 periprosthetic regions and the bladder were compared between PET attenuation corrected with either conventional or MAR CT. RESULTS: Using conventional CT, measured activity decreased with 2 to 13% when the prosthesis was inserted. Use of MAR CT increased measured activity by up to 11% compared with conventional CT and reduced the relative difference with the reference values to under 5% in all sources. In all regions, to the exception of the prosthesis shaft, SUVmean increased significantly (p < 0.001) by use of MAR CT. Median (interquartile range) percentual increases of SUVmean were 1.4 (0.0-4.2), 4.0 (1.8-7.8), 7.8 (4.1-12.4), 1.5 (0.0-3.2), 1.4 (0.8-2.8) in acetabulum, lateral neck, medial neck, lateral diaphysis and medial diaphysis, respectively. Except for the shaft, the coefficient of variation did not increase significantly. Except for the erratic changes in the prosthesis shaft, decreases in SUVmean were rare and small. Bladder SUVmean increased by 0.9% in patients with unilateral prosthesis and by 4.1% in patients with bilateral prosthesis. CONCLUSIONS: In a realistic hip prosthesis phantom, Smart MAR restores quantitative accuracy by recovering counts in underestimated sources. In patient studies, Smart MAR increases SUV in all areas surrounding the prosthesis, most markedly in the femoral neck region. This proves that underestimation of activity in the PET image is the most prevalent effect due to metal artefacts in the CT image in patients with hip prostheses. Smart MAR increases SUV in the urinary bladder, indicating effects at a distance from the prosthesis.