K Preidler — Page 2 | PubMed Health

PubMed1994

Magnetic resonance assessment of age-related development of the sphenoid sinus.

Magnetic resonance images of the sphenoid sinus in 401 patients under 15 years old were reviewed to establish normal age-related standards. T1-weighted sagittal and T2-weighted axial scans were evaluated for bone marrow conversion, development of pneumatization, spatial enlargement and septation of the sphenoid sinus. The sphenoid sinus had a uniformly low signal intensity (red bone marrow) on T1-weighted images in all children less than 4 months old. Signal intensity changes from hypointense to hyperintense (bone marrow conversion) started at the age of 4 months. Onset of pneumatization was observed in 12% of the patients at age 13-15 months. By age 43-48 months, 85% of the patients showed pneumatization of the anterior part of the sphenoid bone. Pneumatization was complete in all patients older than 10 years. Enlargement of the sinus showed a characteristic profile in each dimension. Median septation was observed irregularly with age, with a maximum of 77%. Septum variants were noticed between 4.5% and 20%. Because paediatric sinus disease is a challenging problem in children, these results may be useful as baseline standards of normal age-related development of the sphenoid sinus during childhood.

Adolescent↗

PubMed1993

Correlation between inflection of heart rate/work performance curve and myocardial function in exhausting cycle ergometer exercise.

The heart rate/work performance (fc/W) curve is usually S-shaped but a flattening at the top is not always seen. By means of radionuclide ventricular scintigraphy, the left ventricular ejection fraction (LVEF) of 15 sports students was investigated. The behaviour of the fc/W curve during cycle ergometry with increasing exercise intensities was examined. During exercise, the LVEF showed a distinct initial increase reaching roughly constant values at stress levels below-maximum, and sometimes even falling again. The inflections of the fc/W curve and left ventricular ejection fraction/performance curve (LVEFPC) were calculated from a second degree polynomial fit. From this function, the slopes of the tangents at the points of aerobic threshold and maximum performance were calculated together with the differences of the angles as a measure of the fc/W curve and LVEFPC inflections. It follows that the fc/W curve inflection became less pronounced or was even absent altogether when the decrease in LVEF towards the end of the ergometer exercise became more distinct. A significant negative correlation was found between the existence and extent of the fc/W curve inflection and the stress-dependent myocardial function, expressed as the inflection of the LVEFPC (P < 0.01, r = 0.673). Thus, it would seem that the absence of a fc/W curve inflection was related to a diminished stress-dependent myocardial function.

Adult↗