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Biomedical subjects

M Seiderer

Publications and source records attributed to M Seiderer.

43 records · Page 3Linked to original sources
PubMed1982

[Regional ejection fractions to determine left ventricular function. Comparison of first-radionuclide-pass and equilibrium-radionuclide-ventriculography with the results of cineventriculography].

An analysis of regional left ventricular pump function by regional ejection fractions (rAF) may be done employing First Pass techniques or Equilibrium Radionuclide Ventriculography (MUGA). The ventricle was intersected orthogonally into 5 divisions. This technique was applied to 15 hearts with regular wall motion and to 26 hearts with wall motion abnormalities. The discrimination for wall motion abnormalities of the anterior wall by MUGA was better than using steps of asynergy (normo-, hypo-, dys- and asynergy). With rAF, decrease of regional pump function could be detected (10% of the investigated hearts) even when there was a regular global ejection fraction. Due to the different projection angles for First Pass and MUGA (app. 70 degrees difference), correlation coefficients for anatomically similar divisions of the left ventricle, assessed with both techniques (n = 41) were rather low with the exception of the section belonging to the apex. Assessing the wall motion of the posterior wall, with MUGA isolated wall motion abnormalities could be detected only in 2 out of 6 cases. With First Pass, wall motion abnormalities could be detected in all cases. Therefore, to determine motion and function of the posterior wall, First Pass or even better First Pass and MUGA should be employed since the latter case, the ventricle may be evaluated from two projections in one examination only.

Cardiac Output↗
PubMed1982

A comparison of bone imaging with Tc-99m DPD and Tc-99m MDP: concise communication.

Bone to soft tissue (ST) ratios for both high-uptake bone (sacrum) and low-uptake bone (femoral diaphysis) were obtained with a derivative of phosphonic acid, TC-99m 2,3-dicarboxypropane-1, 1-diphosphonate (DPD), in 26 normal subjects and 177 patients with malignant disease but without metastases. Tests were run 2 hr after tracer injection. Similar ratios were obtained with Tc-99m methylene diphosphonate (MDP) in 220 normal subjects and 451 patients. With MDP, the influence of incubation time (5-10 min in 416 cases, 45 min in 185 cases) on these ratios was determined. DPD was superior to MDP for both ratios. With MDP, prolonged incubation time yielded significantly enhanced ratios; however, the ratios for the DPD were still higher. With either agent and preparation, sacrum-to-ST ratios decreased with increasing subject age, and in patients with malignant disease the ratios tended to be higher than those obtained from normals.

Adult↗
PubMed1981

[First-tracer passage with a single-crystal gamma camera: completed assessment of left-ventricular function by determining enddiastolic volume, regional ejection fraction and %-akinetic segment (author's transl)].

Determination of left ventricular (LV) enddiastolic volume (EDV) was achieved by calibration of the system (single-crystal gamma camera, equipped with a converging collimator) to a volume phantom (egg). A good correlation (r = 0.92) was found with EDV values, obtained from cineventriculography. Images, derived from enddiastole (ED) and endsystole (ES) were corrected for background by "parabolic background subtraction", which is a realistic form of background correction in view of the LV-shape. Regional ejection fraction (REF) was calculated by an electronical operation using the ejection fraction formula and these ED and ES images. REF values reflect regional or segmental LV pump function and are superior to one- or two-dimensional parameters (e.g. visual assessment of asynergy, hemiaxis shortening) since REF values include the third dimension by referring to regional volumes. In addition, per cent-akinetic segment may be replaced by REF. Results from the literature show that first-tracer passage with a single crystal gamma camera at rest (n = 534) yield equivalent results in comparison with cineventriculography. Therefore, this nuclear procedure may be routinely used. REF values complete the diagnostic parameter as yet available.

Cineradiography↗
PubMed1981

[Sonographic determination of thyroid volume. Comparison with other methods (author's transl)].

Using ultrasound it is possible to determine the thyroid volume with a maximal error of 12%. The method is based on the electronic planimetry of a sequence of transverse ultrasound scans of the thyroid. Following this, the "slices" are added using a small computer. On 101 patients five commonly used methods of volume determination were compared with this reference technique. The volume estimation by palpation and interpretation of the scintigram as well as the volume calculation from the scintigram area or from an ellipsoid model gave maximal errors between plus or minus 82% and plus or minus 90%. The combination of scintigram area or scintigraphically determined length and width of a single thyroid lobe and the sonographically measured thickness reduced the maximal error to plus or minus 35% and plus or minus 37%. In 10 patients teh reproducibility of the reference technique was excellent and the absolute maximal error was 4.6%, even when the patients were differently positioned.

Adolescent↗
PubMed1981

[Optimized calculation of left ventricular enddiastolic volume by equilibrium radionuclide ventriculography (MUGA)--the influence of background correction and absorption (author's transl)].

Left ventricular (LV) enddiastolic volume (EDV) was calculated in 23 patients from background-corrected enddiastolic count rates (ROI technique). The calculation in volume units (ml) was based on the measurement of a well-defined amount of patients' venous blood (50 ml in a syringe) counted by the gamma camera. Decrease in count rate due to tissue attenuation was corrected for by calculation of soft-tissue absorption in the thoracic and LV wall as well as the blood self-absorption within the LV, applying a rotational ellipsoid with an assumed LV depth of 1.5 times that of the LV width within the LV ROI. Furthermore, the influence of various models of LV background superimposition (homogeneous, parabolic and no background) were tested correlatively for calculations of volume. Best correlation with cineventriculographically measured volumes (r = 0.92) was found with a parabolically weighed background correction, determining an individual value of background superimposition for each LV pixel. This approach was chosen because a homogeneous superimposition is an inadequate model to correct for background due to the geometric extension of the LV. Volumes, parabolically corrected were found to correlate most closely to cineventriculography (CVG) (VMUGA = 0.997 X VCVG - 12.6 ml).

Cardiac Volume↗