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Biomedical subjects

H Friedburg

Publications and source records attributed to H Friedburg.

At least 19 recordsLinked to original sources
PubMed2002

[Clinical benefit of compensation of motion artefacts in contrast media enhanced MRI mammography].

This article discusses the diagnostic benefit of methods for the compensation of motion artefacts in dynamic MRT-Mammography with a contrast agent. Our algorithms for motion compensation perform a locally rigid registration of cubic sub-volumes and a locally affine deformation of tetrahedral sub-volumes from a Delaunay-Triangulation. Within an extensive clinical study, these fast, automatic, and robust algorithms have been applied to 64 MRT-Mammography datasets from the radiological practice of Dr. Friedburg. The comparison of corrected datasets with original data and the statistical evaluation of results show a significantly improved quality of difference images, particularly at the presence of large motion artefacts.

Adult↗
PubMed1996

Variability of cardiomyocyte DNA content, ploidy level and nuclear number in mammalian hearts.

DNA content, ploidy level, cell size and nuclear number were investigated in 54 mammalian hearts from nine species. DNA content was determined biochemically and ploidy level of cells was studied by the means of Feulgen cytophotometry. Nuclear number was calculated by a new method, while cell size was determined by using ocular micrometry. In most mammals diploid cell nuclei predominate. Higher ploidy levels were found in the human and the pig hearts. The total amount of DNA correlated with the myocardial weight. Eight million heart muscle cell nuclei were found in mice (myocardial weight 160 mg), and 2600 million heart muscle cell nuclei in the human heart (myocardial weight 210 g), but in the hearts of horses up to 35000 million heart muscle cell nuclei (myocardial weight 3.4 kg) were found. The number of heart muscle and connective tissue cell nuclei was correlated with myocardial weight. The ratio of connective tissue cell nuclei to heart muscle cell nuclei was between 2:1 and 3:1. In cardiac growth this ratio shifted towards connective tissue cell nuclei. Increased heart weight corresponds to an increase in cell size. Diameter between 11 microns and 18 microns may be an optimum for heart muscle cells of mammals.

Animals↗
PubMed1991

Pancreatic lesions in the von Hippel-Lindau syndrome.

Common manifestations of the von Hippel-Lindau syndrome, an autosomally dominant inherited cancer-prone disorder, include retinal angiomatosis, hemangioblastoma of the central nervous system, renal cysts, renal cancer, pheochromocytoma, and epididymal cystadenoma. Multiple cysts and microcystic (serous) cystadenomas of the pancreas have also been reported occasionally in patients afflicted with this syndrome. In the large Freiburg study of the von Hippel-Lindau syndrome composed of 66 affected individuals, pancreatic lesions were systematically studied. Fifty-five living individuals were examined by abdominal ultrasound imaging. Abnormal findings were confirmed by computed tomographic scan and/or magnetic resonance imaging. For an additional 11 decreased patients autopsy data were available. Cystic lesions of the pancreas were found in 10 patients (15%). One of these patients presented with multiple pancreatic cysts as the only manifestation of the syndrome. In one patient, a malignant islet-cell tumor was found at autopsy. Because multiple pancreatic cysts did not cause major clinical symptoms and because follow-up examinations over an average period of 5 years did not show significant progression of the lesions, it is concluded that these patients usually do not require surgical treatment. Abdominal ultrasound screening is recommended for patients at risk as a tool to identify potential von Hippel-Lindau syndrome gene carriers with pancreatic manifestations. In all patients with multiple pancreatic cysts, the von Hippel-Lindau syndrome should be included in the differential diagnosis.

Adolescent↗
PubMed1990

Side-effects of extracorporeal piezoelectric shock wave lithotripsy (EPL).

In the Department of Urology, University of Freiburg, West Germany extracorporeal piezoelectric shock wave lithotripsy (EPL) has been used in the treatment of urinary and biliary stones since November 1987. The first 85 treatments (in 71 patients) for renal stones were evaluated with regard to complications and side effects. There was no need for any anesthesia. Urinary obstruction was observed in 12% of the cases. Aside from the urinary obstruction and urosepsis (2%) no serious complications were seen. Endourological auxiliary measures were applied in 32% (27% prophylactically). The temporary glomerular damage which appeared in some patients vanished within 6 days after treatment. Because of possible asymptomatic ureteral obstruction a close follow up by ultrasound is recommended. EPL was found to be a useful method of treatment for renal calculi with few side effects.

Female↗
PubMed1990

Measurement of CSF flow using an interferrographic MR technique based on the rare-fast imaging sequence.

A fast MR sequence based on the RARE-myelographic technique allows the determination of cerebrospinal fluid (CSF) flow with a flow sensitivity below 1 mm/sec. The method averages flow over the ECG cycle and consequently measures net flow rather than ECG-dependent flow variations. The noninvasivity of this technique and the very short acquisition time of about 5 sec make this sequence a very useful diagnostic tool for a variety of CSF-flow dependent disorders like the determination of different types of hydrocephalus, the control of shunt operations and the assessment of communication pathways between CSF and cysts.

Arachnoid Cysts↗
PubMed1990

Rheumatoid arthritis lesions of the wrist examined by rapid gradient-echo magnetic resonance imaging.

Alterations of magnetic resonance imaging (MRI) relaxation time and intensity can be helpful in the diagnosis of rheumatoid arthritis (RA) lesions like synovial infiltration, local inflammation and exudation. Fast low angle shot magnetic resonance imaging (FLASH-MRI) is a rapid method showing anatomy and inflammatory pathology of the examined joint comparable to late spin echo T2 images. The following study presents our results of FLASH-MRI wrist examinations of 15 patients suffering from RA according the ARA criteria and 10 healthy volunteers compared to T1 and T2 weighted MR-images and conventional X-rays.

Arthritis, Rheumatoid↗
PubMed1989

The importance of the voxel size in clinical 1H spectroscopy of the human brain.

It is demonstrated that it is possible to acquire two volume selective 1H NMR spectra of human brain in vivo, consisting of voxels of 1.5 X 1.5 X 1.5 cm3, within 14 min with a good S/N ratio. This is mainly achieved by the application of a PRESS sequence generating a spin-echo of the VOI at 135 ms in conjunction with the STABLE technique by which two spectra can be recorded in an interlaced mode. The Bo homogeneity over such small voxels is considerably higher than over larger voxels. With these methodological improvements it is possible to observe morphological heterogeneity of tumors. The results indicate that spectral changes seem to correlate with the metabolic state of the tumor rather than the tumor type. Additionally the spectrum of a patient with multiple sclerosis suggests that even differentiation between tumors and other lesions might not be possible.

Brain↗
PubMed1989

Hemangioblastomas of the central nervous system. A 10-year study with special reference to von Hippel-Lindau syndrome.

The findings of a 10-year study (1976 to 1986) conducted in southwest Germany on hemangioblastomas (HBL's) of the central nervous system (CNS) are presented. During that period, 47 HBL's were diagnosed and surgically removed in 44 patients, with a good postoperative survival rate and prognosis. The majority (83%) of these tumors were located in the cerebellum. By thorough clinical examination of the patients and careful evaluation of their family background, it was found that 23% of the HBL patients were afflicted with von Hippel-Lindau syndrome. In addition to the CNS tumors, 14 neoplastic or similar lesions were detected in other tissues. These included angiomatosis of the retinae, pheochromocytomas, pancreatic cysts, renal cysts, and renal carcinoma. The diagnosis of von Hippel-Lindau syndrome was thus established in seven families. The authors suggest the need for a screening program for patients with HBL of the CNS which is designed to confirm or exclude ocular or visceral lesions associated with von Hippel-Lindau syndrome.

Adolescent↗
PubMed1988

Quantitative flow measurement with the fast Fourier flow technique.

The fast Fourier flow method of magnetic resonance (MR) imaging offers a fast and efficient way of measuring quantitative flow for velocities within the range from several millimeters per second to more than 1 m/sec. When fast Fourier flow imaging is used in combination with echocardiographic gating, arterial flow can be determined and velocity versus time profiles can be generated. Because of the high spatial resolution, down to 0.3 mm, detailed examination of flow profiles is possible even in smaller vessels. The method works equally well on a low-field-strength system operating at 0.23 T and on a high-field-strength system with 4.7-T field strength. Since the experiment is very fast, with acquisition times ranging from 4 seconds for a single-section experiment to about 4 minutes for the electrocardiographically gated variant, it can easily be combined with a conventional MR imaging examination.

Blood Flow Velocity↗
PubMed1988

[Predictive value of magnetic resonance tomography in comparison with sonography and computed tomography in the diagnosis of focal liver lesions].

Ultrasonography and computed tomography are widely used for the diagnosis of focal lesions of the liver. However, the possibilities for tumor characterization and determination of potential malignancy are limited in many cases. Evaluation by magnetic resonance imaging shows a good correlation of relaxation time with the amount of stroma as a proportion of the total cell content of a lesion. This allows differentiation for a number of lesions. Thus, the combination of ultrasonography and magnetic resonance imaging could provide the ideal diagnostic procedure in many cases.

Adult↗
PubMed1988

[The Cruveilhier-von Baumgarten syndrome. Presentation of radiologic findings based on a case].

Marked portosystemic venous anastomosis of the parumbilical veins is referred to as the Cruveilhier-Baumgarten syndrome. Opening of these vessels has been described mainly in the sonographic literature. In this case report CT and MR findings are presented, which have been confirmed by angiography. This paper is intended to draw the radiologist's attention to dilatation of the parumbilical veins, which is a highly specific sign of portal hypertension resulting from intrahepatic blockage.

Humans↗
PubMed1987

Fast three-dimensional imaging of cerebrospinal fluid.

The RARE method is based on the principle of echo imaging to generate images with high T2 contrast. Since RARE is a fast imaging method, it can be used to acquire a high-resolution three-dimensional data set in less than 15 min. Thin slices from such a three-dimensional data set provide detailed information about the ventricular system.

Cerebrospinal Fluid↗
PubMed1987

Estimation of left ventricular volume and mass by magnetic resonance imaging: comparison with quantitative biplane angiocardiography.

Magnetic resonance imaging (MRI) is well suited for the delineation of cardiac anatomy. In this study an estimation of left ventricular volume and muscle mass by MRI was attempted, using an iron-shielded resistance magnet (Bruker) with 0.23 T. Images were obtained with ECG gating. For image-processing our own software program was used. Slice images were 8 mm thick and spaced 16 mm. Volumes were standardized for a "normal" LV. Muscle mass was calculated directly from the systolic image as the difference between inner and outer ventricular outline. There was a wide range of volumes and mass (100-300 ml, 200-500 g). For comparison and validation conventional biplane left ventriculography was used. Fourteen patients were studied with MRI, but satisfactory studies were obtained in only 7. Correlation of MRI and angiographic volumes was good (r = 0.84). For left ventricular mass it was excellent (r = 0.94). Ventricular walls and cavities were clearly outlined. Even minor details of anatomy were recognized. Limitations of MR study included a narrow space for the patient within the system and the long duration of data acquisition time.

Adult↗
PubMed1987

[RARE-MR myelography in routine clinical practice. Experience with 175 cases].

In 1984 Henning, Nauerth, Friedburg and Ratzel described a new MRI data acquisition technique called RARE (Rapid Acquisition with Relaxation Enhancement). Several clinical applications have been published. A modification developed in the meantime, called "RARE hydrography", yields T2-weighted aqueous fluid specific images within a few seconds. As a nontomographic rapid approach to MR-myelography ("RARE-myelography") this technique is routinely applied at the beginning of all examinations of the spine. On the basis of 175 cases current potentials and limitations are discussed. Future applications of 3D-RARE myelography are mentioned.

Evaluation Studies as Topic↗