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Biomedical subjects

D Hahn

Publications and source records attributed to D Hahn.

At least 217 records · Page 12Linked to original sources
PubMed1988

[Intraneuronal ganglia: value of diagnostic radiologic possibilities].

This report describes two cases of intraneuronal ganglia cysts with degeneration of the peroneal and suprascapular nerve. In addition to standard radiographs other diagnostic studies such as CT and MRI may be required to ascertain the extent of the lesion. Histopathologic information is derived from biopsy.

Adolescent↗
PubMed1988

Subcutaneous implantable infusion device for chronic intravenous pulsatile gonadotropin-releasing hormone treatment.

Preliminary data indicate the potential utility of an implantable subcutaneous device that facilitates chronic intravenous infusion of pulsatile gonadotropin-releasing hormone (GnRH) for ovulation induction. GnRH distribution curves were congruent in control monkeys and those with implanted devices. Tissue tolerance was good in this brief trial. These findings suggest that use of this or a similar implantable device be considered for chronic GnRH administration in human pulse therapy.

Animals↗
PubMed1988

[Diseases of the lymphatic system of the head and neck region. A comparative study of MRI and CT].

The diagnostic possibilities of magnetic resonance imaging compared with computed tomography in lymphomas and pathological enlargement of the lymph nodes in the head and neck region are presented. Whereas plain MRI examinations showed the same diagnostic sensitivity as CT, application of the paramagnetic contrast medium Gd-DTPA in 50 of 87 patients clearly increased diagnostic accuracy. Signal intensities of T1- or T2-weighted images before therapy (operation, chemotherapy, radiotherapy) and after administration of Gd-DTPA were enhanced, compared with posttherapeutic and plain examinations. An increase after therapy in two patients signalled a relapse or residual tumour tissue; a decrease in three cases was evaluated as response to therapy. Other differential diagnostic processes such as lipomas, neurinomas, glomus tumours etc. were differentiated with the help of signal intensity curves after administration of contrast media and the use of a gradient echo sequence TR/TE = 30/12 msec with a flip angle of 30 degrees. Differentiation of tissue based on morphological criteria such as homogeneity of tumour tissue or the delineation against surrounding tissue structures showed in the case of Hodgkin's disease and inflammatory diseases mainly homogeneous elements without ring-shaped structure. Non-Hodgkin lymphomas had a predominantly homogeneous structure. In squamous cell carcinomas MR revealed in two cases a ring-shaped enhancement.

Adult↗
PubMed1988

[Arthrography of the wrist joint in determination of the prosthesis site].

Arthrography was performed during the last 12 months in 14 patients who had 2 months to 10 years after implantation of a silicone-elastomer- or fascia-lata-prosthesis recurrent complaints in their operated wrists. Following an extensive radiological native examination either midcarpal or radiocarpal arthrography was performed in dependence of the site of carpal-bone-substitute. Inflammatory changes of the prosthetic bed, missing penetration of contrast medium into the periprosthetic space and other less common additional findings showed the advantages of the relatively handsome procedure.

Adolescent↗
PubMed1987

[Value of high-resolution CT and nuclear magnetic resonance tomography compared to the standard procedures in the diagnosis of meniscal lesions].

The knees of 20 patients with evidence of meniscal tears were examined via high-resolution computed tomography (HRCT); 10 of these were studied by MRI. The HRCT study was performed directly after double-contrast arthrography (AG). For comparison with HRCT, slice orientation for MRI examination was in transverse view; gradient echo sequences using the FISP technique were applied instead of spin echo sequences. All results were correlated to the arthroscopy (AS) findings. In 95% of the cases AG and AS results agreed, HRCT/AS in 85% and MRI/AS in 70%. In certain cases HRCT provided additional information which influenced appropriate surgical treatment. MRI is a noninvasive nonionising method but gives a less exact documentation of the lesion than AG and HRCT. The gradient echo mode is superior to the SE mode in respect of outlining meniscal structures, at least in transverse view.

Adult↗
PubMed1987

[Determination of T2-times of tumor and muscle tissue by nuclear magnetic resonance tomography and resonance spectroscopy--results of a comparative study].

In 13 patients the T2 values of muscular and various tumor tissues was determined by MR under in-vivo conditions. The tumors were confirmed by surgery. In 5 cases there was a neurinoma of the acoustic nerve, in 3 cases a lateral neck cyst, a granuloma of the larynx and some other pathological processes. Intraoperatively the tissues are biopsied and the T2* time is determined by spectroscopy in vitro. Both the muscular and the tumor tissue show higher mean values or standard deviations in MR measurements than in measurements by spectroscopy. The relations between muscular and tumor tissue (quotients) are comparable in neurinomas of the acoustic nerve (n. vestibulo-cochlearis) and lateral neck cysts, the granuloma of the larynx and lymph nodes of the neck, using both examination methods. Calculations of the correlation coefficients of T2 values and quotients of the muscular and tumor tissue point to tissue-specific connections between in-vivo and in-vitro measurements.

Head and Neck Neoplasms↗
PubMed1987

[Imaging of the Achilles tendon using magnetic resonance tomography].

The Achilles tendon and pre-achillean space of 30 patients was studied by MRI. A surface coil (Helmholtz' principle) was applied and all patients were examined with a superconducting magnet operating at 1.0 Tesla field strength. The purpose of the study was to illustrate pathological changes of the tendon and the surrounding soft tissue. In 3 cases MRI diagnosed a total rupture of the Achilles tendon. Furthermore, the strain of the tendon and side effects of an inflammatory process could be demonstrated. The use of a surface coil yields a high resolution of the normal anatomy of the region and of the pathological changes of the tendon and the surrounding soft tissue structures. The advantages of MRI for Achilles tendon diagnostics against competitive modalities are excellent soft tissue contrast, multiplanar imaging, as well as exact delineation and visualisation of the lesion.

Achilles Tendon↗