Biomedical subjects
Publications and source records attributed to U Piepgras.
Internal carotid aneurysm in the petrous canal are rarely observed. According to our knowledge there are only 24 reported cases. We present the case of a 47-year old woman. The clinical, radiological and histological findings are discussed.
It is possible to develop faster sequences with 6 mT/m gradient field strength. However, the short gradient switch times which are advantageous for a better image contrast cannot be achieved. Using longer measurement times the influence of the preparation pulses is less dominant. The image quality of the quickflash is poorer than that of conventional SE and GE sequences. In some cases, especially for outline views and in the evaluation of Gd inflow into pathologic tissue or in restless patients, we use the quickflash in clinical routine.
Up to 5 years ago, the radiological diagnosis of leukodystrophy was based on computed tomography (CT). More recently, magnetic resonance imaging (MRI) has been used to study pathology of the white matter with great success. The abnormalities in eight patients with different types of leukodystrophy are described, using high-field MRI. CT and MRI show comparable sensitivity in detecting the pathological changes of leukodystrophy. MRI seems to be superior in visualizing the extent of the lesions, their precise anatomical location and any involvement of the brain stem and cerebellum. Differential diagnosis among the three types of leukodystrophy by MRI is difficult but may be attempted by some features. Specific diagnosis can be achieved only by laboratory examination or histology. The role of MRI should be to suggest the proper biochemical test at an earlier stage.
Fourteen patients suffering from myasthenia gravis underwent cranial MRI and 99mTc-HM-PAO SPECT examinations. T2-WI revealed solitary white matter and/or basal ganglia lesions in four, multiple lesions in eight patients. The evaluation of the rCBF demonstrated a circumscript decrease of cortical perfusion in one patient whereas eight patients showed multiple cortical areas of hypoperfusion. In the context of an increased incidence of intrathecal immune reaction as well as of a constantly impaired cognitive performance of these patients, imaging findings might be a correlate of a primary cerebral manifestation of myasthenia.
In contrast to angiography, MRI not only allows the diagnosis of DVA (developmental venous anomaly, so-called venous angioma), but also shows up cavernomas and other angiographically occult vascular malformations. It also differentiates between DVAs and occult true malformations. This has completely changed the pathological assessment of DVAs. In a retrospective study on 31 patients with angiographically proven DVAs neighbouring cavernoma was a frequent finding (15 patients, 48% group I). Symptoms caused by cavernoma were present in 6 (40%) of these 15 patients. The following associations were also found: cerebral arterial aneurysm (2), spinal arterio-venous dural fistula (1), dermal haemangioma (1), Klippel-Trénauny syndrome (1). Only 16 (52%) of the 31 cases with DVA were free of associated cavernoma (group II). Only 3 (19%) of these patients with a solitary DVA were symptomatic. In our series we have seen no case of bleeding from a DVA. A DVA is a vascular anomaly characterized, like other anomalies, by reduced resistance and limited capacity for regulation and adaptation. In rare cases this can result in haemodynamic disturbances, thrombosis and ischaemia. Wall rupture with bleeding does not occur in DVA. It must be assumed that bleeding reported in patients with DVAs before the availability of MRI resulted from an associated true vascular malformation in most cases.
Clinical presentation of a child with port-wine stain and seizures leads to the suspicion of Sturge-Weber disease (SWD). This diagnosis can be confirmed by the detection of a meningeal angiomatosis. In rare cases, early detection of meningeal pathology by ultrasound has been reported. Key findings are brain atrophy, gyriform cortical calcifications demonstrated by skull radiographs after the first year of life or earlier by cranial CT, and dys- or aplasia of the deep cerebral veins on angiography. Radionuclide imaging shows focal or diffuse tracer accumulation over the affected brain regions. MR demonstrates an abnormal appearance of the affected meninges, especially thickening and pathologically increased signal intensity after Gd-DTPA application. This, in association with the demonstration of abnormal enhancement in deep medullary veins, is the most characteristic finding. Contrast-enhanced MR allows early and non-invasive diagnosis of SWD, mainly by revealing leptomeningeal angiomatosis and abnormal venous vessels.
Radionuclide cisternography is indicated in the clinical work-up for hydrocephalus, when searching for CSF leaks, and when testing whether or not intracranial cystic lesions are communicating with the adjacent subarachnoid space. This paper demonstrates the feasibility and diagnostic value of SPECT and subsequent 3D surface rendering in addition to conventional rectilinear CSF imaging in eight patients. Planar images allowed the evaluation of CSF circulation and the detection of CSF fistula. They were advantageous in examinations 48 h after application of 111In-DTPA. SPECT scans, generated 4-24 h after tracer application, were superior in the delineation of basal cisterns, especially in early scans; this was helpful in patients with pooling due to CSF fistula and in cystic lesions near the skull base. A major drawback was the limited image quality of delayed scans, when the SPECT data were degraded by a low count rate. 3D surface rendering was easily feasible from SPECT data and yielded high quality images. The presentation of the spatial distribution of nuclide-contaminated CSF proved especially helpful in the area of the basal cisterns.
The progress of experimental hydrocephalus-hydromyelia in cats is analyzed in the present study. The animals were rendered hydrocephalic by intracisternal injections of kaolin or by operatively occluding the lateral apertures. Changes in the cerebrospinal fluid (CSF) spaces were monitored by ventriculography or computed tomography. The progress of hydrocephalus in both groups can be divided into two stages: 1) A phase of raised intracranial pressure precedes the dilatation of the central canal, and 2) a progressive phase follows the dilatation of the central canal. The canal acts as a kind of natural bypass between the ventricles and the subarachnoid spaces. Although the spontaneous shunt, the central canal, becomes dilated and pressures drop to near normal values, the disease is apparently not brought to a complete halt. Our observations suggest that the disturbance in CSF flow dynamics is an important factor causing hydrocephalus to remain progressive.
A prospective study was carried out in 29 patients to test the validity of the combined and simultaneous use of isotope cisternography and CT cisternography in the diagnosis of cerebrospinal fluid rhinorrhea. One of the conclusions reached was that a combination of the two procedures possibly gives the easiest and most effective diagnosis.
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The possibilities of quantitative evaluation of skull computer tomograms were explored in a group of 22 normals and compared with a group of 26 patients with cerebral tumours. Quantitative measurements of normal cerebral tissue and of tumours have revealed mean values for these groups which permit certain fundamental conclusions.
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CT cisternography and CSF scintigraphy are indispensable in the detailed morphologic and etiologic evaluation of special types of childhood hydrocephalus. In addition these investigations afford interesting insights into CSF dynamics in apparently complete membranous or tumorous obstruction of the fourth ventricle and into the genesis of internal hydrocephalus in cerebellopontine angle tumors.
Results of microzone electrophoresis of non-concentrated CSF after staining with nigrosine and after evaluation on non-transparent acetate film are compared with those of isotope cisternography (111In-DTPA). We found that blood-CSF barrier disturbances begin with an increase of the absolute values of prealbumins in normal CSF circulation. When a barrier impairment occurs, by first increasing the absolute values of alpha1-globulins, we state a pathological CSF circulation. In this case, most of the globulin region is pathologic (globulin-type).
1. Computer tomography is much more clearly superior to cranial scintigraphy with regard to the identification and localization of pathologic infratentorial processes, than in the supratentorial range. 2. Computer tomography alone solves many diagnostic problems relating to the infratentorial range, but it cannot by any means solve all the problems. 3. The diagnosis identifying the kind of infratentorial growing and displacing tumors cannot be safely established either by computer tomography alone or by a combination of computer tomography and cranial scintigraphy. 4. Cranial scintigraphy and CSF scintigraphy can supply additional informations, support the diagnosis, or contribute towards establishing the final diagnosis, in cases where computer tomography alone supplies ambiguous, questionably positive or discrete answers. In such cases, the emphasis is on the etiologic grouping of unclear forms of hydrocephalos.
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