Biomedical subjects

Stefan Feuerbach

Publications and source records attributed to Stefan Feuerbach.

39 records · Page 3Linked to original sources

PubMed2002

Screening for osteoporosis in patients with inflammatory bowel disease by using urinary N-telopeptides.

BACKGROUND: Patients with inflammatory bowel disease are at increased risk of osteoporosis. DESIGN AND METHODS: We carried out a prospective study of bone mineral density and biochemical markers of bone metabolism like osteocalcin and urinary N-telopeptides in 72 patients with inflammatory bowel disease and evaluated if one of these markers detects osteoporosis. In addition, bone mineral density and N-telopeptides were analysed retrospectively in a second series of 93 patients with inflammatory bowel disease in order to assess predictive values found in the first patient group in an independent sample. RESULTS: Multiple linear regression showed that N-telopeptides (P < 0.0001) and total white blood cell count (P = 0.006) correlated negatively with the bone mineral density of the lumbar spine and only N-telopeptides (P = 0.005) correlated negatively with the bone mineral density of the femoral neck. Using receiver operator characteristic curves N-telopeptide concentrations of > 40 (30) nmol N-telopeptides/mmol creatinine were chosen as best cut-off values to exclude osteoporosis at the lumbar spine (femoral neck). Using these cut-off values a negative predictive value of 100% (100%) and a positive predictive value of 37.5% (27.9%) were found in the first group, and a negative predictive value of 95.2% (96%) and a positive predictive value of 15.6% (23.3%) in the second, independent group of patients. CONCLUSION: Our data suggest that N-telopeptide levels could be used as a tool for the screening of osteoporosis and for selecting those inflammatory bowel disease patients where bone mineral density measurement is indicated.

Adult↗

PubMed2002

Magnetic resonance imaging in patients diagnosed with papilledema: a comparison of 6 different high-resolution T1- and T2(*)-weighted 3-dimensional and 2-dimensional sequences.

PURPOSE: To evaluate visualization and signal characteristics of macroscopic changes in patients with ophthalmologically stated papilledema and to find a suitable high-resolution magnetic resonance imaging (MRI) protocol. METHOD: Nine consecutive patients with 12 ophthalmologically stated papilledemas underwent MRI of the head and orbits, which consisted of the following high-resolution sequences: 3-dimensional (3D), T2*-weighted (T2*w) constructive interference in steady-state sequence (CISS); 3D, T1-weighted (T1w) magnetization prepared-rapid gradient echo sequence (MP-RAGE) (with and without intravenous contrast medium); transverse 3D and 2-dimensional (2D) (2 mm), T2-weighted (T2w) turbo spin echo (TSE); transverse 2D (2 mm), contrast-enhanced T1w TSE with fat-suppression technique; and transverse 2D (5 mm), T2w TSE. A quantitative and qualitative evaluation of the papilla, optic nerve, optic nerve sheath, optic chiasm, and the brain was performed. The 6 high-resolution sequences were compared. RESULTS: The elevation of the optic disc into the optic globe in ophthalmologically stated papilledema was best visualized in T2w, 3D CISS sequence. The pathological contrast enhancement was best seen in T1w contrast-enhanced 2D TSE sequence with fat-suppression technique. The mean width of the optic nerve sheath directly behind the globe was 7.54 mm (+/- 1.05 mm) in the pathological eyes, compared to 5.52 mm (+/- 1.11 mm) in the normal eyes. In all patients, the cerebral indices calculated showed no signs of increased intracranial pressure or other abnormalities changing the volume of the brain or ventricles. The contrast of the orbital fat versus the optic nerve sheath, the optic nerve sheath versus the surrounding cerebrospinal fluid (CSF), the surrounding CSF versus the optic nerve, the optic chiasm versus the CSF, and the optic papilla versus the optic globe were best visualized in the 3D, T2*w CISS sequence. An enhancement of the swollen optic nerve head was best seen in all 12 cases in the T1w contrast-enhanced 2D TSE sequence with fat-suppression technique. CONCLUSION: An MRI protocol consisting of a 5-mm transverse T2w TSE sequence; a T2*w, 3D CISS sequence; a T1w, 3D MP-RAGE sequence with and without contrast medium; and a transverse T1w, (2-mm) 2D TSE sequence with fat-suppression technique with intravenous contrast medium is suitable to visualize the macroscopic changes in papilledema. In addition, this combination is an excellent technique for the examination of the orbits and the brain.

Adolescent↗

PubMed2002

Routine chest radiography using a flat-panel detector: image quality at standard detector dose and 33% dose reduction.

OBJECTIVE: The purpose of this study was to evaluate the effectiveness of a large-area, flat-panel X-ray detector for performing routine chest radiography at two different detector doses. MATERIALS AND METHODS: The chest radiographs of 50 patients (age range, 16-79 years; mean age, 57 years) were obtained at two different detector dose levels. Digital images were taken from the same patients in posteroanterior and lateral views with detector doses of 2.5 microGy and 1.8 microGy, respectively, at 125 kVp tube voltage. The cesium iodide-amorphous silicon active-matrix imager had a panel size of 43 x 43 cm, a matrix of 3000 x 3000, and a pixel pitch of 143 microm. Images were presented in a random order to three independent radiologists who were unaware of the dose level at which the images had been obtained. They subjectively rated image quality on a 4-point scale, according to six criteria (presentation of obscured lung, unobscured lung, airways, mediastinum and hilum, bony thorax, and overall impression). Statistical significance of differences was evaluated with Student's t test for paired samples (confidence level, 95%). RESULTS: Digital radiographs obtained at 2.5 and 1.8 microGy were equivalent on all quality criteria. No statistically significant differences and no tendency toward a preference for images obtained at one or the other dose level were observed. According to the registered mAs values, the average difference in patient dose was 33%. CONCLUSION: Use of flat-panel digital imagers based on the cesium iodide-amorphous silicon technique allows a considerable dose reduction during routine chest radiography without loss of image quality.

Adolescent↗