PubMed Health⌕ Search

Biomedical subjects

J Boese

Publications and source records attributed to J Boese.

8 recordsLinked to original sources
PubMed2004

Perfusion CT in patients with advanced bronchial carcinomas: a novel chance for characterization and treatment monitoring?

Advanced bronchial carcinomas by means of perfusion and peak enhancement using dynamic contrast-enhanced multislice CT are characterized. Twenty-four patients with advanced bronchial carcinoma were examined. During breathhold, after injection of a contrast-medium (CM), 25 scans were performed (1 scan/s) at a fixed table position. Density-time curves were evaluated from regions of interest of the whole tumor and high- and low-enhancing tumor areas. Perfusion and peak enhancement were calculated using the maximum-slope method of Miles and compared with size, localization (central or peripheral) and histology. Perfusion of large tumors (> 50 cm3) averaged over both the whole tumor (P = 0.001) and the highest enhancing area (P = 0.003) was significantly lower than that of smaller ones. Independent of size, central carcinomas had a significantly (P = 0.04) lower perfusion (mean 27.9 ml/min/100 g) than peripheral ones (mean 66.5 ml/min/100 g). In contrast, peak enhancement of central and peripheral carcinomas was not significantly different. Between non-small-cell lung cancers and small-cell lung cancers, no significant differences were observed in both parameters. In seven tumors, density increase after CM administration started earlier than in the aorta, indicating considerable blood supply from pulmonary vessels. Tumor perfusion was dependent on tumor size and localization, but not on histology. Furthermore, perfusion CT disclosed blood supply from both pulmonary and/or bronchial vessels in some tumors.

Adult↗
PubMed2003

Quantitative and qualitative assessment of left ventricular volume with ECG-gated multislice spiral CT: value of different image reconstruction algorithms in comparison to MRI.

PURPOSE: To assess the value of different image reconstruction algorithms for assessment of the left ventricular function using retrospectively ECG-gated multislice spiral computed tomography (MSCT) of the heart. MATERIAL AND METHODS: MSCT and cine magnetic resonance (MR) imaging of the heart were performed in 15 patients. For MSCT, standard and multisegmental image reconstruction with improved temporal resolution were used. Standardized multiplanar reformats in the short axis and long axis views were reconstructed from MSCT data. End-systolic (ESV) and end-diastolic volume (EDV), stroke volume (SV), ejection fraction (EF) and myocardial mass (MM) were calculated. Left ventricular wall motion was assessed qualitatively. RESULTS: MSCT was in acceptable agreement with MR imaging for quantification of the ventricular function. According to the Bland-Altman approach the mean differences for the left ventricular volumes (ESV, EDV, SV) ranged from -9.6 ml to 3.1 ml with standard image reconstruction and from -0.6 ml to 1.9 ml utilizing multisegmental image reconstruction with limits of agreement ranging from -26.6 ml to 12.5 ml and -15.6 ml to 15.0 ml, respectively. Applying the multisegmental image reconstruction algorithm, a significantly improved agreement with the MR data was found for EDV, SV and EF. For wall motion analysis, standard image reconstruction showed a significant difference to MR imaging with a correspondence in 83.75% of the 240 assessed segments, while multisegmental image reconstruction agreed with MR imaging in 92.5% of the segments. CONCLUSION: Multisegmental image reconstruction improves the quantitative assessment of left ventricular function when compared to standard image reconstruction. Multisegmental image reconstruction allows qualitative wall motion analysis.

Adult↗
PubMed1995

General relation between variance-time curve and power spectral density for point processes exhibiting 1/f beta-fluctuations, with special reference to heart rate variability.

Counting statistics in the form of the variance-time curve provides an alternative to spectral analysis for point processes exhibiting 1/f beta-fluctuations, such as the heart beat. However, this is true only for beta < 1. Here, the case of general beta is considered. To that end, the mathematical relation between the variance-time curve and power spectral density in the presence of 1/f beta-noise is worked out in detail. A modified version of the variance-time curve is presented, which allows us to deal also with the case beta > or = 1. Some applications to the analysis of heart rate variability are given.

Animals↗
PubMed1975

Investigations into the determination of the cytotoxicity of quartz dust by physical methods.

The methods of thermally stimulated luminescence (t.s.l), thermally stimulated exoelectron emission (t.s.e.e.), electron spin resonance (e.s.r), and infrared spectroscopy (i.r.) have been used to investigate whether the specific cytotoxic activities of SiO2 dust of various origins can be attributed to physical parameters. After interaction of toxic dusts with water an increase in the intensity of the t.s.l. peaks below room temperature has been detected whereas no effect could be observed in the case of inert materials. Dusts of weak cytotoxicity have been characterized by infrared absorption bands at 3610 cm-1 and 3685 cm-1. The results of the present studies emphasize the significance of silanol groups and adsorption properties in relation to the fibrogenic activity of quartz dusts.

Dust↗
PubMedDate not supplied

Extraction of light filth from whole peppermint leaves: collaborative study.

Results are reported for a collaborative study of a method for the extraction of light filth from whole peppermint leaves. A 5 g sample is defatted with isopropanol in a simple reflux appartus. Rat hairs, insect fragments, and whole insects are isolated by wet sieving on a No. 230 sieve, a deaerating boil in 40% isopropanol solution, flotation with Tween 80-Na4EDTA (1 + 1) and mineral oil-heptane (85 + 15), and trappings in a Wildman trap flask. Average recoveries obtained by 6 collaborators for 3 spike levels of rat hairs (5, 10, 15) were 83.3, 87.5, and 82.2%, respectively. For whole insects (5, 10, 15) recoveries averaged 85.0, 80.0 and 77.2% respectively; for insect fragments (20, 30, 50) recoveries averaged 79.6, 88.3, and 84.8%, respectively. The average recoveries for the 3 levels of each analyte were not significantly different. The method has been adopted official first action.

Animals↗