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Biomedical subjects

N Hosten

Publications and source records attributed to N Hosten.

At least 145 records · Page 8Linked to original sources
PubMed1994

[Osteoplastic bone metastases in prostatic carcinoma: magnetic resonance tomography and bone marrow scintigraphy].

MRI of the vertebral column was performed in 28 patients with histologically confirmed prostate carcinoma. Besides routine spin-echo sequences all patients were examined with gradient-echo sequences using the chemical shift mode. In addition, in all patients bone marrow scintigraphy (BMS) was performed, and all results were compared with routine bone scan (BS). In our study BMS was not superior to bone scan. In contrast, MRI scan revealed solitary metastases in two patients with negative BS and BMS. Osteoplastic metastases showed a contrast enhancement in the MRI and could be distinguished from benign alterations.

Aged↗
PubMed1994

[Color-coded duplex sonography in the differential diagnosis of cervical lymph node enlargements].

55 patients with cervical lymph node enlargement were studied prospectively by colour coded duplex sonography. The aim was to demonstrate the perfusion of individual lymph nodes and to determine whether the resistance and pulsatile index are able to show the cause of the enlargement. The lymph nodes were subsequently examined histologically. Useful perfusion measurements were obtained in 177 lymph nodes out of 216. Perfusion index < 1.6 and resistance index < 0.8 distinguishes between reactive lymph node enlargement and lymph node metastases with an accuracy of 91%. Reliable differentiation between lymphoma and metastases was not possible. Tuberculous lymph nodes and cysts showed significantly reduced resistance and pulsatile index when compared with metastases. Further information on the type of disease was obtained from the perfusion patterns. Reactive lymph nodes showed increased central perfusion of the hilum, whereas metastases tended to show increased peripheral perfusion.

Diagnosis, Differential↗
PubMed1994

[Communication and integration of medical documents for the teleconference use. An outcome of the BERMED project].

The collaboration between physicians is supported in the BERMED project by implementing the remote access to distributed patient data and the realisation of computer-based medical conferencing. This requires the integration of the multimedia data in form of a meta-patient record for our medical application systems. These applications are supported by a distributed information management promoting access to different information systems, imaging modalities and digital archival storage systems. The features of image processing are concerned with quantification, segmentation and 3-D-visualisation to obtain additional information. This paper gives an overview of the actual state of the teleconferencing system in radiology.

Computer Communication Networks↗
PubMed1994

[The spiral CT of orbital space-occupying lesions: improved imaging possibilities via freely reconstructible planes].

In a prospective study the value of spiral CT for the detection and differential diagnosis of intraorbital masses was investigated. Thirty patients with various orbital diseases were examined with transverse spiral computed tomography. After performing two contiguous 1 mm spiral CT scans, coronal, parasagittal, and other reconstructions were obtained. Compared with separately generated 2 mm slices, the 1 mm spiral CT images showed a slightly decreased signal-to-noise ratio, but due to the better spatial resolution, the image quality of secondary reconstructions was similar to that of the original transverse spiral CT slices. Generally the orbital masses were visualized best in the coronal reconstruction. In certain cases, the parasagittal reconstructions were superior. Reconstructions in freely definable slice planes based on 1 mm spirals provides better visualization of orbital diseases without increasing radiation dose. This method allows multiplanar reconstructions similar to magnetic resonance tomography.

Adolescent↗
PubMed1994

[Cerebral arteriovenous angiomas: 3-dimensional demonstration by spiral CT].

In 20 patients with known or suspected supratentorial arteriovenous malformations, an attempt was made to see how far CT angiography with 3-dimensional reconstructions is able to make a diagnosis and to differentiate the various components of the angioma. Spiral CT was performed following an intravenous bolus injection of 60-80 ml of iodine containing contrast medium. In all patients the diagnosis was confirmed by intra-arterial DSA of the vertebral vessels. In 13 patients, av malformations could be diagnosed following multiplanar 3-D reconstructions which agreed with the findings on DSA. The large supplying vessels, the nidus and the large draining veins could be defined with certainty. In 6 patients follow-up examination after embolisation was performed. The results could be demonstrated in three dimensions and the success of treatment could be documented unequivocally. CT angiography with 3-D reconstruction is able to supply important information in the majority of intracranial av malformations, both during initial investigation and following treatment.

Adolescent↗
PubMed1994

Enlarged cervical lymph nodes at helical CT.

PURPOSE: To evaluate criteria for differentiating malignant versus reactive lymph nodes in the head and neck on the basis of findings at helical computed tomography (CT). MATERIALS AND METHODS: Helical CT scans were evaluated of 70 consecutive patients (46 men and 24 women, aged 20-78 years [mean, 51 years]) with known head and neck tumors and cervical lymph node enlargement. The ratio of the maximal longitudinal to the maximal axial diameter (L/T) was calculated for nodes larger than 8 mm in diameter based on measurements obtained from coronal, paraxial, and sagittal reconstructions. RESULTS: At histologic examination, 96 of 164 nodes were malignant. Of these, 94 of 96 nodes had an L/T of less than 2 (sensitivity, 97%; specificity, 97%; accuracy, 97% for malignancy). Minimal diameter was more than 8 mm in 83 of 96 nodes (sensitivity, 87%; specificity, 89%; accuracy, 88% for malignancy). Low-attenuation centers and rim enhancement were seen in 75 of 96 nodes (sensitivity, 78%; specificity, 100%; accuracy, 86% for malignancy). CONCLUSION: The L/T at helical CT provide an accurate assessment of reactive versus malignant nodes in the head and neck.

Adult↗
PubMed1994

[Current status of magnetic resonance tomography in diagnosis of the ankle joint--a critical evaluation].

Anatomical preparations of the ankle were examined by T1-weighted SE-sequences in three planes to identify normal topography. The current status of magnetic resonance imaging (MRI) was assessed and illustrated by image examples. Together with conventional radiography, MRI yields relevant information for therapy planning. This technique allows accurate staging of traumatic and degenerative involving the soft tissues of the joint, including tendons and ligaments. MRI clearly delineates joint fluid, osteochondral abnormalities, and is helpful in the diagnosis of inflammatory changes of the synovia and bone marrow. Furthermore, it is the modality of choice for evaluating tissue neoplasma. Its advantages are not only the detection of the process and definition of its extent, but also the determination of local soft-tissue infiltration.

Ankle Injuries↗
PubMed1994

[MRT in degenerative diseases of the cervical spine].

MRI has grown increasingly important in recent years in diagnosis of degenerative disease of the cervical spine, due to improvements of method that have made it a valuable diagnostic tool. The following contribution gives a brief introduction to the pathophysiology of degenerative changes in the cervical vertebral column and to the indications for MRI, describing within the framework of imaging the present state of MR examination technique. The ranking of the various gradient echo sequences, of the 3D methods and of the administration of contrast media in cervical myelopathy and radiculopathy is discussed.

Cervical Vertebrae↗
PubMed1994

MR of brain involvement in progressive facial hemiatrophy (Romberg disease): reconsideration of a syndrome.

PURPOSE: To gain further insight into the pathogenesis of progressive facial hemiatrophy, a sporadic disease of unclear etiology characterized by shrinking and deformation of one side of the face. METHODS: We investigated possible brain involvement. MR of the head and face was performed in three female patients with progressive facial hemiatrophy. The central-nervous-system findings were correlated to a clinical protocol and a review of the literature. RESULTS: One patient with epilepsy had abnormal brain findings confined to the cerebral hemisphere homolateral to the facial hemiatrophy. These consisted of monoventricular enlargement, meningocortical dysmorphia, and white-matter changes. CONCLUSIONS: These MR findings, and corresponding neuroradiologic data disclosed by the review, indicate that homolateral hemiatrophy occasionally occurs in a subgroup of patients with progressive facial hemiatrophy. The MR features do not seem consistent with an underlying simple or nutritive atrophic process. We propose chronic localized meningoencephalitis with vascular involvement as a possible underlying cause of the occasional brain involvement in progressive facial hemiatrophy.

Adult↗
PubMed1994

Hyperostosis in meningiomas: MR findings in patients with recurrent meningioma of the sphenoid wings.

PURPOSE: We used MR imaging to analyze retrospectively the pattern of hyperostosis occurring concomitantly with recurrent sphenoid wing meningiomas. METHODS: Bone involvement was compared in 12 corresponding CT and MR studies of 10 female patients with sphenoid wing meningiomas recurrence after earlier surgical treatment. Four of these had histologically confirmed meningiomatous infiltration of the bone. RESULTS: All patients had CT findings of localized hyperostosis of parts of the sphenoid wings. MR revealed inhomogeneous areas of slightly increased signal intensity in hyperostotic bone on T2-, proton density- and T1-weighted sequences. In nine of 10 patients, segments of the hyperostotic bone showed different degrees of gadolinium enhancement. CONCLUSIONS: Because earlier studies have revealed high incidences of meningiomatous bone infiltration in sphenoid wing meningiomas, and because infiltration was confirmed in four of our patients, we postulate that the gadolinium enhancement in the area of hyperostosis may be related to meningiomatous bone infiltration.

Adult↗
PubMed1993

[Spiral CT: differential diagnosis of cervical swelling. Initial clinical results].

Spiral CT examinations were performed pretherapeutically in 27 patients in whom cervical lymph node enlargement had been suspected. The M/Q quotient known from sonography and MR can also be employed in CT by means of coronary and sagittal reconstruction. This improves CT differentiation between reactively changed and metastatically infiltrated lymph nodes in tumour patients. Hence, CT diagnosis can now make use of a highly sensitive and highly specific criterion for diagnosing lymph nodes. Another diagnostic improvement is that vascular infiltrations by lymph node metastases can now be visualised or excluded more readily. Spiral CT is also suitable in tumorous and non-tumorous processes for an accurate assessment of the extension of e.g. retropharyngeal abscesses or laryngoceles.

Abscess↗
PubMed1992

[Cervical lymph node metastases. The sonographic demonstration of malignancy].

The value of sonography for demonstrating cervical lymph node metastases has been studied, using longitudinal and transverse measurements as criteria for malignancy. A transverse/longitudinal quotient greater than 2 indicates the presence of metastases with a 96% assurance. Using only longitudinal measurements lymph node metastases can be excluded with only a 36% assurance. The sensitivity of both methods also differs (95% for the maximal transverse quotient as against 90% for longitudinal measurements). The use of the maximal transverse quotient increases specificity from 36 to 96%. This gives sonography an accuracy of 95%.

False Negative Reactions↗
PubMed1992

[Magnetic resonance tomographic screening studies of the bone marrow with gradient-echo sequences. II. Gadolinium-DTPA-supported studies of plasmocytoma patients].

MR imaging was performed in 19 patients with proven multiple myeloma. Both plain and Gd-DTPA enhanced in-phase and opposed-phase gradient-echo techniques were used (0.1 mmol Magnevist/kg body weight). Plain, opposed-phase imaging demonstrated more lesions than plain in-phase imaging (35 vs. 16); enhanced opposed-phase imaging demonstrated more lesions than plain opposed-phase and enhanced in-phase imaging (47 vs. 35 and 17 lesions). These results suggest that enhanced opposed-phase images which have a high contrast between normal and infiltrated bone marrow are especially suited for MR screening in multiple myeloma.

Bone Marrow↗
PubMed1992

[The magnetic resonance tomography of intracranial ependymomas. Their clinical appearance and comparison with computed tomography].

The MRT and CT images of histologically confirmed intracranial ependymomas in 10 patients have been compared. All tumours were demonstrated by CT and MRT. The solid portions of the tumours showed variation in density on CT (hypodense, isodense, hyperdense, or mixed), whereas there was uniform signal intensity on MRT (T1 weighted: hypointense, T2 weighted: hyperintense). Cystic portions of the tumours (6 patients) were shown equally well by both procedures, calcifications were only shown by CT. All ependymomas were related to the ventricles. On unenhanced CT only 3 tumours were clearly delineated, whereas MRT defined all tumours satisfactorily. The significant advantage of MRT is better topographic demonstration of the tumour.

Adolescent↗
PubMed1992

[The course of the disease in endocrine orbitopathy. Magnetic resonance tomographic documentation].

MR imaging of the orbits was performed in 59 patients with untreated Graves' ophthalmopathy (follow-up exams were performed in 11 patients). T2-relaxation times of eye muscles were calculated and correlated with duration of disease. Elevated T2 times indicating eye muscle edema were found even if ophthalmopathy had been existing for more than one year. MRI documented specific eye muscle changes and transformation of oedema to fibrosis and fatty degeneration. MRI thus allows for standardized planning of therapy and follow-up in patients with Graves' ophthalmopathy.

Edema↗
PubMed1992

Cyclo(L-prolyl-L-N-methylphenylalanyl). Conformation in solution and in the crystal.

Detailed analysis of the proton and carbon-13 NMR spectra of cyclo(L-prolyl-L-N-methylphenylalanyl) in chloroform and methanol in relation to its nonmethylated analog provided information on the conformation of the title compound in solution as well as on the effect of N-methylation and solvation. The X-ray structure of the title compound in the crystalline state showed the same conformational features as the solution structure. The phenyl group folds over the diketopiperazine ring which resembles a flattened half-chair. Both amide bonds are considerably nonplanar. The pyrrolidine ring of proline shows a strong pucker at the ring junction with the largest chi 5 value hitherto observed.

Dipeptides↗