Biomedical subjects

N Hosten

Publications and source records attributed to N Hosten.

At least 127 records · Page 7Linked to original sources

PubMed1995

Telemedicine in rural areas. Experience with medical desktop-conferencing via satellite.

Cooperation between physicians in hospitals in rural areas can be assisted by desktop-conferencing using a satellite link. For six weeks, medical desktop-conferencing was tested during daily clinical conferences between the Virchow-Klinikum, Berlin, and the Medical Academy, Wroclaw. The communications link was provided by the German Telekom satellite system MCS, which allowed temporary connections to be established on demand by manual dialling. Standard hardware and software were used for videoconferencing, as well as software for medical communication developed in the BERMED project. Digital data, such as computed tomography or magnetic resonance images, were transmitted by a digital data channel in parallel to the transmission of analogue video and audio signals. For conferences involving large groups of people, hardware modifications were required. These included the installation of a video projector, adaptation of the audio system with improved echo cancellation, and installation of extra microphones. Learning to use an unfamiliar communication medium proved to be uncomplicated for the participating physicians.

Germany↗

PubMed1995

Cervical lymphadenopathy: ratio of long- to short-axis diameter as a predictor of malignancy.

The purpose of this study was to evaluate short- and long-axis diameters of enlarged cervical lymph nodes with ultrasonography and to determine whether the long-to-short axis (l/s) ratio is a valid diagnostic parameter in the differentiation between benign and malignant nodal disease. 730 enlarged cervical lymph nodes in 285 patients were examined with ultrasound. The short- and the long-axis diameters of each enlarged node were measured and the l/s ratio calculated. Definite diagnoses of the nodes were obtained by histological examination following neck dissection. 95% of enlarged cervical nodes shown on ultrasound to have a l/s ratio of more than 2 were correctly diagnosed as benign. Nodes presenting with a more circular shape and a l/s ratio of less than 2 were diagnosed correctly as metastases with 95% accuracy. The l/s ratio of lymph nodes thus provides an excellent criterion for differentiation between benign and malignant enlargement in cervical lymphadenopathy.

Adult↗

PubMed1995

[Magnetic resonance of brain involvement in progressive facial hemiatrophy (Romberg's disease). Reconsideration of a syndrome].

UNLABELLED: Progressive facial hemiatrophy (PFH) is a sporadic disease of unclear etiology, characterized by shrinking and deformation of one side of the face. Reports and interpretations of CNS involvement in PFH, as deduced from the occurrence of seizures in some patients and documented by pneumoencephalography and CT findings in small series of patients, are contradictory. We examined three female patients with PFH, one with partial epilepsy, with the view to gaining further insight into the pathogenesis of the disease. METHODS: Routine MR examinations of the head and face were performed. RESULTS: Only the patient with epilepsy showed pathological findings, confined to the cerebral hemisphere homolateral to the facial hemiatrophy, and including monoventricular enlargement, meningo-cortical dysmorphia and white matter changes. CONCLUSIONS: The MR morphology, and corresponding neuroradiological and histopathological findings disclosed by a review of the literature, indicate that homolateral hemiatrophy is a typical finding for a subgroup of PFH patients, but do not support the model of a simple or nutritive atrophic process. We reconsider chronic localized meningo-encephalitis with vascular involvement as possible underlying cause of the occasional brain involvement in PFH.

Adult↗

PubMed1995

[Ultrasound detection of breast cancer with normal mammogram].

In eleven patients with breast cancer the diagnosis was made by using ultrasound as the only method. In none of the patients could mammography show the malignoma. Although six of the patients underwent additional tube X-ray investigation, no radiological criteria of malignancy were found on the mammograms. In ten patients a lump of the breast was palpable and/or retraction of the skin was visible. In one woman, neither the clinical investigation nor the mammography could reveal the tumor. The ultrasound of the breast is a indispensable and useful method for diagnosing breast cancer.

Adult↗

PubMed1995

[Megadolichobasilar artery as a rare cause of hydrocephalus internus: synopsis of modern imaging methods].

Megadolichobasilarartery (MDB), i.e. the widened, elongated and tortuous course of the basilar artery, has been the topic of numerous publications; about 350 cases have been reported world-wide. It can cause many symptoms; isolated or combined cranial nerve lesions and ischemic or hemorrhagic changes are the most frequent. A hydrocephalus internus is a rare occurrence and many patients do not exhibit any symptoms. To date, angiography, computed tomography, and to an increasing extent magnetic resonance imaging (MRI) are the principal methods for diagnosis of MDB. Angiographic-like representations with CT and MRI are further developments which represent an alternative to angiography. With the help of special MRI sequences, furthermore, non-invasive CSF flow measurements for the etiologic evaluation of a hydrocephalus can be performed. For the example of a patient with MDB and hydrocephalus internus, the possibilities of modern imaging techniques are presented and discussed.

Basilar Artery↗

PubMed1995

[MR urography with the T2-weighted turbo-spin-echo sequence].

Tumor-induced dilatation of the urinary tract is difficult to diagnose in the distal part of the ureter, including the stenosis, by ultrasound and X-ray. Often on account of renal insufficiency and allergy, i.v.-contrast media cannot be used. The present study should show the suitability of fast T2-weighted (turbo-) spin-echo sequences (T2-TSE) for MR-urography (MRU). Seven patients (62.3 +/- 6.1 years) were examined in the coronal plane with T2-TSE sequence (TR = 4500 ms, TE = 160 ms) and an MRU was calculated by using the MIP method (maximal intensity projection). This technique enabled urogram-like morphological representation of dilated urinary tract including stenosis in 6 of 7 patients. Assuming a high magnetic field homogeneity, MRU by using a T2-TSE-sequence, without i.v.-contrast media administration, can visualize the urinary tract dilatation and localize tumor-induced stenosis.

Adult↗

PubMed1995

[Estimating patient dose in computerized tomography].

This paper presents a model for the estimation of the effective patient dose in computed tomography. It is demonstrated how equivalent organ doses for selected examination can be estimated on the basis of the scanner-specific axis dose and published conversion factors. Problems and limitations of this method are discussed. The determination of the effective dose from the organ equivalent dosis is explained. The explanations are illustrated by an exemplary calculation, and the doses of the most important CT examinations are summarised.

Body Burden↗

PubMed1995

[Spondylitis: borderline findings in magnetic resonance tomography].

MR studies of 41 patients with confirmed spondylitis were evaluated with regard to imaging findings resembling metastases or fracture. 30 patients had MR results considered typical for spondylitis (contiguous changes in two vertebrae and disc, soft tissue tumour). 11 patients had MR studies differing from this pattern. Absence of soft tissue involvement and discontinuous marrow changes may be misdiagnosed as bone marrow metastases.

Adult↗

PubMed1995

[Estimating patient dose in radiologic examinations using conversion factors].

The principles for estimation of the patient's radiation dose from conventional radiographic and computed tomography examinations are presented on the basis of published exposure simulation data. The relationship between absorbed dose in air, or axis dose, organ doses, and effective dose is explained. It is shown how organ doses can be calculated from the absorbed dose free in air or axis dose using published computed conversion factors. Calculation of the effective dose from organ doses using tissue weighting factors is described. Finally, examples of dose calculation are given for a conventional radiographic and a CT examination.

Body Burden↗

PubMed1995

[Digital image intensification radiography in endoscopic retrograde cholangiopancreatography].

The standard in ERCP is the use of the conventional radiography system. Digital radiography system are very seldom used in ERCP, and then mostly by digital luminescence radiography. In this study we report our experience with digital image amplification radiography (DIAR) in ERCP. We examined 53 patients of clinical routine aged from 21 to 90 years. During the ERCP we used the X-ray statues and the real-time exposures. At the end of an examination the image post-processing followed. Both conventional and digital image amplification radiography needed the same examination conditions. The special X-ray protection (special lead-shields) used at digital ERCP did not hinder the examination. The DIAR provided at least the same amount of information as conventional radiography. An advantage of DIAR is the possibility of image post-processing such as contrast change, zooming, etc., and the digital archiving and communication. The examination time was reduced by about 30% as compared conventional ERCP, resulting in a reduction of the X-ray exposure time for the patients. The disadvantages of DIAR can surely be compensated by a high ERCP-rate.

Adult↗

PubMed1995

[Technique and economics of first worldwide roentgen conference via public phone lines with the Medical Desktop-Conference and Integrated Services Digital Network].

The introduction of the world's first Medical Desktop-Conference via public phone lines (ISDN-S2M) in spring 1994 for the weekly discussion of radiological findings with 25 orthopedic surgeons has proved the effectiveness of this system developed by the project BERMED. The use of standard hard- and software as well as ISDN are the most important factors to keep the system costs low. Technical advantages can be seen in the immediate, loss-free transmission of image and other patient-related data and in the integration of digital archives. Medical advantages are the 24-hour-availability of the radiologist and quality-control of the radiologists work. Practitioners and external hospitals can be tied closely to radiological service centers by using ISDNetwork.

Computer Communication Networks↗

PubMed1995

[Space-occupying lesions of the lacrimal gland in CT and MRI exemplified by 4 cases].

In an extended case report, we discuss four cases with masses in the lacrimal fossa representing the most important entities in this region (lymphoma, pleomorphadenoma, inflammatory pseudotumor, and malignant epithelial tumor). The different indications for CT and MRI are explained. For the differential diagnosis of lacrimal gland lesions, the following imaging parameters are important: the shape of the lacrimal gland, the inner structure, the degree of contrast enhancement, and the surrounding bony structures. In the evaluation of the expansion of lacrimal gland lesions, CT in thin slices with multiplanar reconstructions is equal to MRI. However, the contrast-enhancement of lacrimal glands is better evaluated with MRI than with CT. The bony structures are better visualized on CT than on MRI.

Adenoma, Pleomorphic↗

PubMed1994

Spinal cord sarcoidosis.

We present a case of spinal cord sarcoidosis which resembled a disseminated intramedullary tumour. The case is unusual because the spinal cord is only rarely affected by sarcoidosis and the patient developed a neurological deficit as the first manifestation of the disease. This condition thus has to be considered in the differential diagnosis of primary intramedullary tumours, or metastatic disease with involvement of the spinal cord.

Diagnosis, Differential↗

PubMed1994

[[111In]-DTPA-D-phenylalanine octreotide SPECT for the scintigraphic imaging of enhanced somatostatin-receptor density in endocrine ophthalmopathy].

Recently, [111In]-DTPA-D-phenylalanine-octreotide was introduced for clinical use. This radioligand binds specifically to somatostatin receptors and is suitable for SPECT examinations. The aim of this study was to clarify whether an increased somatostatin receptor density can be imaged and quantified in patients with endocrine ophthalmopathy (e.o.). 7 patients between 34 and 55 years with e.o. at stages III to VI and 4 controls between 38 and 63 years were examined. All patients and controls received approximately 200 MBq [111In]-DTPA-D-phenylalanine-octreotide by IV injection. A SPECT examination was performed 4 hours after injection and a normalised tracer uptake (A(n)) was calculated for both orbitae. In patients with e.o. the values of A(n) were significantly higher compared with controls (P = 0.002). There was a correlation between A(n) and exophthalmus stages according to Hertel with r = 0.844 (P = 0.001). These results indicate that [111In]-DTPA-D-phenylalanine-octreotide SPECT might be useful for the in vivo assessment of an increased somatostatin receptor density in e.o. These findings could have an impact on the treatment with somatostatin analogous in e.o.

Adult↗

PubMed1994

[Cerebral aneurysms: their 3-dimensional imaging with spiral CT].

In this study, the possibility of non-invasive, three-dimensional demonstration of aneurysms of the basal cerebral arteries by means of spiral CT was investigated. The first step was to obtain exact definition of optimal examination parameters. Angio CTs at appropriate levels were performed on 10 subjects and time/density curves of the arterial and venous phases obtained in order to optimise the beginning of the arterial spiral CT series. The second step in this investigation was to examine 7 patients; in 6 of these basal aneurysms had been demonstrated by DSA. By means of multiplanar three-dimensional reconstruction from the data of the spiral CT it was possible to demonstrate 7 aneurysms with a diameter between 5 and 18 mm. Their position and relationship to the bony skull was also shown.

Adult↗

PubMed1994

[Indications for the application of a high resolution coil in MR tomography].

This is the first study with high spatial resolution Magnetic Resonance Imaging (MRI), performed with a high resolution coil in a clinical whole-body system. Measurements were recorded with a slice thickness of 2 mm. A 256 x 256 matrix and a 2.5 cm field of view were used resulting in a pixel size of 0.01 mm2. MR images of the skin, hand, wrist, knee and ankle of 14 healthy volunteers, of three anatomic pathology tissue specimens and of three formalin-fixed specimens were obtained. Normal anatomy was identified and compared with the three gross anatomic pathology sections. The skin, hands, wrists and ankles of 30 patients were examined and a variety of pathological lesions were detected, including cutaneous neoplasms and ulceration, acute and chronic tendon lesions and pathologic features of the bone and wrist. Based on the excellent imaging of anatomic detail and superior contrast resolution, high resolution MRI proved an important complement for preoperative diagnosis.

Adult↗

PubMed1994

[The spiral CT of cervical lymph node enlargements. The initial clinical results].

Spiral CT was performed before treatment in 35 patients with suspected cervical lymph node enlargement. By coronary and sagittal reconstruction it is possible to utilise the M/Q quotient which has become accepted as the result of sonographic and MRI examinations. It is now possible to obtain high diagnostic accuracy (97%) for distinguishing between reactive change from metastatic infiltration of lymph nodes (> 8 mm) by using CT. Using spiral CT with 5 mm table movement, three patients diagnosed as stage N1 by axial CT were shown to be N2b. This represents a highly sensitive and highly specific method of lymph node diagnosis. Further diagnostic improvement derives from the ability to relate the lymph nodes to surrounding tissues. Spiral CT is also suitable for defining other space occupying lesions, e.g., the exact extent of retropharyngeal abscesses, abnormalities of the salivary glands or laryngoceles.

Abscess↗

PubMed1994

[The use of the T2-weighted turbo-spin-echo sequence in studying the neurocranium. A comparison with the conventional T2-weighted spin-echo sequence].

T2-weighted spin-echo imaging is the standard screening procedure in MR imaging of the neurocranium. We evaluated fast spin-echo T2-weighted imaging (TT2) of the neurocranium in comparison to conventional spin-echo T2-weighted imaging (T2). Signal-to-noise and contrast-to-noise ratio of normal brain tissues (basal ganglia, grey and white matter, CSF fluid) and different pathologies were calculated. Signal-to-noise ratio and contrast-to-noise ratio were significantly higher in TT2 than in T2 (with the exception of gray-to-white matter contrast). Tissues with increased content of water protons (mobile protons) showed the highest contrast to surrounding tissues. The increased signal intensity of fat must be given due attention in fatty lesions. Because the contrast-to-noise ratio between white matter and basal ganglia is less in TT2, Parkinson patients have to be examined by conventional T2. If these limitations are taken into account, fast spin-echo T2-weighted imaging is well appropriate for MR imaging of the neurocranium, resulting in heavy T2-weighting achieved in a short acquisition time.

Adult↗