PubMed Health⌕ Search

Biomedical subjects

E Löhr

Publications and source records attributed to E Löhr.

At least 19 recordsLinked to original sources
PubMed1994

[Individual variability in the duration of the second phase of the mixed dentition].

With a collection of dental casts from a longitudinal study of 175 orthodontically untreated probands (100 children without and 75 children with premature loss of deciduous molars and/or canines) serving as a base, the duration of the second period of mixed dentition was determined to be in relation to the probands the period of time between the gingival emergence of the first permanent buccal tooth and the full eruption of the set of teeth. The second period of mixed dentition in boys without premature loss of deciduous molars and canines lasts on an average 3.6 +/- 1.1 years and in girls 3.8 +/- 1.0 years. In cases of premature loss of deciduous molars and/or canines, the period of dentition is distinctly longer than under normal development conditions. The outside parameters (boys: Xmin = 0.9 years, Xmax = 6.2 years; girls: Xmin = 2.6 years, Xmax = 8.6 years), reflect a high degree of variability. The duration of the second period of mixed dentition is significantly affected by "the point in time of inception" and by the criteria "morphologically intact support zones" and "premature loss of deciduous molars and/or canines". Even given such data, however, it is not possible to make a sufficiently reliable prediction on an individual basis of the duration of the dentition.

Child↗
PubMed1994

[High-resolution 3-D imaging in MR tomographic knee joint diagnosis. Correlation with arthroscopy].

84 knee joints were examined by a 3-dimensional MR method and the results correlated with subsequent arthroscopy. The findings showed good demonstration of the normal anatomical structures and excellent reliability for the diagnosis of meniscus tears (sensitivity 91%, specificity 95%), cruciate ligament lesions (sensitivity 90%, specificity 99%) and serious cartilage damage (sensitivity 100%, specificity 100%). Demonstration of mild cartilage damage (sensitivity 60%, specificity 99%) was better than with a spin echo technique but is not yet optimal. It is concluded that, by using a 3-dimensional technique, time-consuming spin echo sequences can be abandoned. Significant advantages of the 3-D method are the speed of the examination, narrow section thickness, marked flexibility in contrast rendering and the ability for multiplanar reconstruction.

Adolescent↗
PubMed1994

[Color velocity imaging for diagnosis in kidney transplants. Methods for interpretation of color coding].

Colour velocity imaging is a new technique in the field of colour-coded sonographic flow measurement. It measures blood flow directly by analysing ultrasound pulses' running time and has advantages over colour Doppler systems. Colour velocity imaging's colour code detects changes in arterial blood flow. Therefore it can be used in the diagnosis of kidney allografts in the same way as duplex ultrasound. Using the presented methods of colour interpretation, sensitivity of 66.6-100% and specificity of 72.7-91.7% are attained. Thus colour velocity imaging combines the attributes of duplex ultrasound and colour Doppler ultrasound.

Blood Flow Velocity↗
PubMed1994

[Flow time analysis in sonographic flow measurements: an in vitro measurement for testing their accuracy].

Flow-time analysis is a new technique for colour coded sonographic flow measurements. The measurements depend on a pattern of ultrasound pulses and have some significant advantages compared with Doppler procedures. The accuracy of the method and possible sources of error have been studied under experimental conditions. Measurements on continuous blood flow showed a correlation of r > 0.99 for duplex sonography and of r > 0.93 for flow-time analysis. For this method, the colour coding parameters must be optimal in order to achieve high accuracy. Under these conditions quantitative measurement of pulsatile flow also becomes possible during colour mode.

Color↗
PubMed1993

[Primary diagnosis of osseous carpal area injuries--a comparison of conventional examination methods with digital luminescence radiography].

Despite recent progress in improving diagnostic methods carpal bone lesions are still a major problem of primary diagnosis. Diagnostic imaging with digital luminescence radiography (DLR) allows the reliable presentation of traumatologically relevant carpal structures. In this study on 39 patients with suspected carpal bone injuries individually worked over DLR images were superior to "standard" DLR and conventional X-ray film/screen images. Though "standard" DLR images were inferior to film images edge-enhanced DLR images showed definite advantages in the demonstration of soft tissues. Fractures undetectable in conventional X-rays could not be recognized by digital imaging. In our experience bone-scanning remains the most reliable method for definite exclusion of carpal bone fractures after standard and digital X-ray methods are exhausted.

Adolescent↗
PubMed1993

Evaluation of tumor blood perfusion by dynamic MRI and CT in patients undergoing thermoradiotherapy.

In 18 patients who were treated with combined regional hyperthermia and radiation for recurrent pelvic tumors, blood flow related data were obtained using dynamic computed tomography and dynamic magnetic resonance imaging. The enhancement of contrast material (delta HU) and Gadolinium DTPA (delta SI) over baseline in the early phase (15-30 s) after bolus injection is dependent upon perfusion. With both methods significant differences in global perfusion have been observed between tumor center and tumor periphery. With regard to the mean perfusion values we are able to separate high, medium and low perfused pelvic tumors. Flow rates expressed as delta HU for dynamic CT and delta SI for dynamic MRI show a significant inverse correlation with the achieved steady state temperatures above baseline. Values of enhancement of contrast material higher than 15-35 delta HU or 300-700 delta SI indicate flow rates which were limiting in achieving steady state temperatures higher than 3 degrees C above baseline (core temperature).

Combined Modality Therapy↗
PubMed1993

[Duplex ultrasound evaluation of Basedow struma treated with iodine therapy].

Over a period of 18 months the thyroid gland of 31 patients suffering from Grave's disease was examined by Duplex ultrasound for changes in blood perfusion. In 24 of these patients a follow-up study was achieved immediately after a presurgical iodine therapy. For estimation of the perfusion the "Pulsatile Flow Index (PFI)" was calculated. Compared to the normal group (22 volunteers, mean: 0.46 +/- 0.11) changes of 41 and 22% were highly significant for this pre (mean: 0.65 +/- 0.08, p < 10E-6) and post therapy (0.56 +/- 0.1, p < 5E-5). Therapy was unsuccessful in 3 cases on a single, in one case on both sides. Altogether PFI yielded semiquantitative information on blood perfusion of the gland as well as on the rate of success.

Adolescent↗
PubMed1993

[Are high-intensifying film-screen combinations suitable for the detection of fine interstitial lung changes? The results of a ROC study with an anthropomorphic thorax phantom].

Exposures of an anthropomorphic thorax phantom in posteroanterior projection were made using a focus-film distance of 200 cm and 125 kV with film-screen combinations in class 200 (Curix RP 1L/MR 200) and class 400 (Curix ST-L/Regular). Pathomorphological structures of the lung parenchyma of fine nodular, linear and reticular types were simulated by suitable materials. A ROC analysis including a t-test showed no significant difference in the evaluation of these structural details (p > 0.05). In order to describe image quality for the two film-screen systems, density curves, sigma D-curves and modulation transfer function (MTF) were determined. The only demonstrable difference was reduced MTF of 10-15% for the higher intensification film-screen combination with a resulting poorer resolution of 3.7 l/mm (for the 400 system) compared with 4.3 l/mm for the 200 system.

Evaluation Studies as Topic↗
PubMed1993

Radiological aspects of arteriosclerosis: follow-up study of 588 patients in two different groups.

The authors retrospectively compared two groups of patients who had undergone angiography over a twenty-one-year period. The first group consisted of 348 patients who had angiography in the years 1965-1967. The second group was made up of 222 patients who had had angioplasty in the years 1975-1986. Special risk factors such as diabetes and nicotine abuse were singled out together with localization of lesions and gender distribution.

Adult↗
PubMed1993

Changes of soft-tissue water examined with magnetic resonance and electrical impedance tomography: an in vivo experiment.

The purpose of this study was the examination of short-term changes in soft-tissue water under in vivo conditions. In 12 healthy volunteers the water distribution of a selected slice of the lower limb was examined after change of position and rapid infusion of 0.9% saline solution. Two methods were used for data acquisition: magnetic resonance imaging (MRI) (Repetition Time (TR) = 1600 msec, Inversion Time (TI) = 300 msec, Echo Time (TE) = 22 msec) and electrical impedance tomography (EIT). In orthostatic equilibrium all 12 volunteers demonstrated changes of MR signal intensity and resistivity in the range of 12% and 7%, respectively. After infusion, mean changes of signal intensity and resistivity were 7% and 4%, respectively. The overall correlation of MRI and EIT was -0.96 (p < 0.001). Results indicate that inversion recovery sequences are a sensitive method of detecting in vivo changes of water distribution in selected areas of the body.

Adult↗
PubMed1991

[Digital luminescence radiography (DLR) for skeletal diagnosis in traumatology].

170 patients who had suffered trauma to bones or soft tissues were examined by a digital and a conventional film/screen technique. In addition to "standard" and edge-enhanced images, post-processing was carried out and compared with conventional radiographs. Four radiologists and two surgeons evaluated the compacta, spongiosa, soft tissues, fractures and osteo-synthetic materials as shown on the two systems. The "standard" digital images are inferior to film images, but edge-enhanced images showed definite advantages for demonstrating soft tissues. Evaluation of osteo-synthetic material is limited by the creation of artifacts. Recognition of detail can be significantly improved by using post-processing with optimized parameters.

Adolescent↗
PubMed1991

Angioplasty of renal arteries: a report of ten year's experience.

Report of PTA of renal arteries in 288 patients. Primary results show good to optimal dilatation of the arteries (60.6% to 78.6%). One third of all cases achieved optimal blood pressures. In about 40% antihypertensive drugs had to be administered, in about 30% blood pressure remained unchanged although PTA was effective. PTA of renal arteries is the best method of treating renal hypertension, also because of the low rate of complications.

Angioplasty, Balloon↗
PubMed1991

[Roentgen diagnosis of pulmonary complications following allogeneic bone marrow transplantation--application of and experience with digital luminescence radiography].

Pulmonary complications exercise a decisive influence on the prognosis of leukaemia patients after bone marrow transplantation. Very early diagnosis is a mandatory prerequisite to successful therapeutic intervention. Of great importance besides the clinical findings and bronchoalveolar lavage is the analysis of the x-ray morphology of pneumonic infiltrates to narrow down the differential diagnostic spectrum. Since the patients are at high risk of infection, they are under isolated care, so that x-ray examinations can only be performed by means of projection radiography using mobile units. Due to these difficulties in performing relevant radiography the required optimal and constant image quality cannot be achieved by means of conventional x-ray film, so that very early detection of pulmonary complications is not always possible. The use of digital luminescence radiography (DLR) with luminescent storage foils enables a highly constant and hence comparable image quality thanks to increased image dynamics, a larger area of the examined object, and histogram evaluation of the image data for determining the optimal parameters for assessment. In addition, details can be better identified to supply answers to specific questions, because the image can be reprocessed to select relevant image parameters by monitoring. Pulmonary complications in 86 patients were analysed retrospectively. These patients had received an allogeneic bone marrow transplant for acute myeloic leukaemia, after they had been treated with high-dose radio-/chemotherapy. The x-ray morphology, clinical and sometimes autopsy findings were correlated with the occurrence of pulmonary complications subsequent to bone marrow transplant.

Adolescent↗
PubMed1990

[The diagnostic value of captopril radionuclide nephrography for renovascular hypertension in childhood].

In four children the role of captopril-radionuclide nephrography in the diagnosis of renovascular hypertension was studied. Captopril (0.5-1.0 mg/kg orally) did not affect Iodine-123 Hippuran nephrography in two children with mild renal artery stenosis, but induced an accumulation of the tracer within the kidneys in two children with hemodynamically significant renal artery stenosis. As in adults Iodine 123 Hippuran nephrography appears to be a useful tool to identify patients with significant renal artery stenosis.

Adolescent↗
PubMed1989

Duplex Doppler ultrasound in determination of renal artery stenosis.

Twenty-six cases of renal artery stenosis were evaluated with Doppler ultrasound using the pulsatile flow index (PFI). To establish normal values, the PFI in 60 renal arteries in 30 healthy volunteers was obtained. Normal values by PFI ranged between 0.48 and 0.71 (mean +/- SD: 0.6 +/- 0.06). In renal artery stenosis the PFI range was 0.72-0.79. The normal upper limit was 0.71. The PFI failed in three patients; however, an ultrasound examination showed secondary renal disease (two patients with stenosis on both sides with a shrunken kidney on one side, and one patient with hypernephroma on the opposite side). The PFI was normal (14 of 14 patients) in patients without angiographic evidence of stenosis or after successful dilatation.

Humans↗