Biomedical subjects
W Stork
Publications and source records attributed to W Stork.
[Modulation transfer function and contrast sensitivity of refractive multi-zone multi-focal lenses].
Contrast imaging of new multifocal intraocular lens (MIOL) designs with 5 and 7 refractive zones was examined by in vitro measurement of the modulation transfer function (MTF) and by testing contrast sensitivity with Regan 96% and 11% contrast sensitivity charts after "optical implantation" of MIOLs in 20 healthy subjects by means of a new optical device developed by Reiner. The results were compared with those obtained with a monofocal IOL and a diffractive MIOL. We found that the MTF of both refractive MIOLs showed a reduction in contrast at corresponding spatial frequencies compared with the monofocal and with the diffractive IOL, resulting in a Strehl ratio of below 30%. Contrast sensitivity after "optical implantation" was significantly reduced for the refractive 5- and 7-zone models in high contrast (Regan 96%), but for all MIOL models in low contrast (Regan 11%) compared with the monofocal IOL. The refractive 5-zone MIOL and diffractive MIOL showed no statistical difference in contrast sensitivity.
Endotheliomatous meningioma with coalescing microcysts, presenting as an hypodense lesion with ring enhancement on computed tomography.
Computed tomography (CT) revealed a hypodense intracranial tumour that showed a slight ring enhancement and a peripheral tumour nodule. Although this suggested a cystic astrocytoma, angiography identified a meningeal tumour. Microscopical examination demonstrated a cystic endotheliomatous meningioma. Neuropathological and intraoperative findings suggested that the meningioma was an intermediate form between the microcystic and macrocystic types, illustrating the evaluation from the former to the latter.
[Magnetic resonance tomography of prostatic cancer. A histopathologic correlation].
A total of 52 patients with prostatic carcinoma were examined by MR imaging; 14 of them subsequently underwent radical prostatectomy and were included in this study. The resected prostates were sectioned axially and compared with the corresponding MR scans with special reference to the location and extent of the pathological changes. The prostatic carcinoma was visualized in 10 cases, but the size of the tumor was underestimated in 6 patients. In 9 of 10 patients the carcinoma was identifiable as an area of low signal intensity within the peripheral zone on T2-weighted images. The MR features of benign nodular hyperplasia are discussed.
Doppler sonographic examination of reactive hyperemia in the diagnosis of peripheral vascular disease.
Fifty-four patients with angiographically confirmed peripheral vascular disease (PVD) were examined in order to find out whether the occlusive form of this disease can be better diagnosed by measuring the reappearance time and mean velocity of the blood flow during reactive hyperemia than by determining the peripheral systolic blood pressure, using Doppler ultrasound for both measurements. It was shown that the Doppler pressure was only reliable for a screening diagnosis of PVD. However, using the reappearance time of reactive hyperemia, it was possible to distinguish specific localization types of sclerosis; while reactive hyperemia already reached its half maximum in controls in 4.6 s this occurred in the stenosis type of PVD after 6.9 s, in the upper leg occlusion type after 21.6 s, in the lower leg occlusion type after 46.6 s, and in the multilevel disease after 70.1 s. The delay in the half-maximum reappearance time was significantly different, not only in comparison with controls (P less than 0.001) but also in the specific types of occlusive PVD as compared with one another (P less than 0.01). Regarding the intensity of velocity it could also be shown that the mean velocity of blood flow during reactive hyperemia was lower in all patients with PVD than in controls. Again this alteration during reactive hyperemia was significant, not only in comparison with controls (P less than 0.001), but also when the specific stages of severity according to Fontaine were compared with one another (P less than 0.05).2+n the basis of these findings it can be stated that in
Magnetic resonance (MR) imaging in the management of primary and secondary syringomyelic cavities, and of other cystic lesions of the spinal cord.
During the past three years 27 patients with medullary and/or brainstem cavities were examined with MRI at the Institute of Roentgenology, and we report the radiological MRI correlative findings. Five patients were operated: postoperative MRI examinations were compared with preoperative studies. Syringomyelia was present in 21 cases, syringobulbia in 2, and syringobulbomyelia in 4. Additional pathology such as the Arnold Chiari malformation or hydrocephalus was found at the craniospinal junction in 8 patients. Two instances of associated intraspinal tumours were noted too. In all cases the syringomyelic cavities involved the cervical cord and in most of them the lesion extended down to the thoracic or even lumbar level. Several patients were shown to have multilocular cavities. In the patients with syringomyelia a syringoarachnoidal shunting procedure was performed. This resulted in cyst collapse as proved by postoperative MRI examinations; neurological symptomatology was ameliorated too. Conventional radiological imaging with computed tomography (CT) and myelography was not as efficient as MRI in imaging syringomyelia. The extent of intramedullary cavities as well as the presence of associated pathology is best appreciated on sagittal MRI. The use of special surface coils clearly results in better image quality due to higher resolution. According to our experience MRI should be the primary examination in syringomyelia; myelography and CT are obsolete in the management of syringomyelia; the insertion of a syringoarachnoidal shunt is a convenient surgical procedure, resulting in clinical amelioration in most cases.
Measurement of pulse reappearance time in diagnosis of peripheral vascular disease in diabetes.
Forty-eight patients (20 diabetic, 28 nondiabetic) with angiographically confirmed peripheral vascular disease (PVD) were examined to discover whether the measurement of pulse reappearance time (PRT) during reactive hyperemia is a more useful method than the measurement of peripheral systolic blood pressure (ankle pressure index; API) for making a specific diagnosis of PVD. Specific diagnosis refers to the degree and localization of occlusive atherosclerosis determined by Doppler ultrasound techniques for both measurements. We found that PRT and API both provided accurate qualitative proof of a peripheral blood flow deficit in diabetic and nondiabetic subjects. However, in relation to the angiographically defined degree and localization of sclerotic lesions, there were significant differences. The sclerotic degree of occlusive PVD in diabetic subjects was correlated with the results of the PRT (P less than .001), whereas the API was not (P greater than .05). The occlusion localization could only be distinguished by PRT measurements in both diabetic and nondiabetic subjects. Compared with control subjects (4.1 s) the half-maximum PRT of blood flow velocity was delayed in stenotic PVD to 5.7 s, in occlusive PVD of the upper leg to 14.3 s, in occlusive PVD of the lower leg to 29.6 s, and in multilevel disease to 45.0 s (P less than .0005 vs. control). The results show that Doppler sonographic measurement of the peripheral systolic blood pressure is only useful for an overall diagnosis of PVD in diabetic subjects, whereas PRT measurement, by quantifying the degree and localization of sclerotic lesions, can be used additionally either to confirm or to specify this diagnosis.
Magnetic resonance imaging of colloid cysts of the third ventricle.
Two cases of colloid cyst of the third ventricle are reported. Their computed tomographic (CT), magnetic resonance (MR) and neuropathological features are presented. The MR findings were different in the two cases for reasons not yet fully explained, full biochemical and biophysical analyses of the cyst contents not being available. Neuropathologically, the only significant difference was the abundant presence of cholesterin crystals in the colloid of case 1 and their absence in case 2. One of our cases is also peculiar from a CT point of view, since it was primarily hypodense and did not enhance on intravenous contrast administration.
Damage of thalamus and basal ganglia in asphyxiated full-term neonates.
Thalamic-striatal damage of symmetric bilateral distribution was found in four severely asphyxiated neonates born at term. Two patients showed evidence of bilateral thalamic-striatal necrosis and two showed hemorrhage of the same distribution. The four patients had a common history of prolonged asphyxia in the neonatal period combined with severe acidosis and respiratory insufficiency. The outcome was lethal in all children. Three patients survived for some time and showed additional evidence of generalized brain damage including cortical necrosis and subcortical leucomalacia and one patient was found to have intravital calcification of the putamen at 14 days of age. The appearance of thalamic-striatal damage in US, CCT and NMR imaging is discussed. Thalamic-striatal damage may not be detectable by US until several days after the initial insult. US does not permit a distinction between necrosis and hemorrhage, but CCT and NMR imaging may be successful. Only five infants with a comparable pattern of brain damage due to asphyxia have been described so far. Our own studies seem to indicate that thalamic-striatal damage is the hallmark of more widespread brain damage, and that it will be found more frequently if carefully looked for in asphyxiated neonates born at term.
NMR studies in thalamic-striatal necrosis.
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[Bilateral breast cancer (author's transl)].
The frequency of bilateral primary (simultaneous and nonsimultaneous) breast cancer in 1420 patients was reported. The number of cases of bilateral breast cancer not caused by metastases amounted to 1,75%. The problems and significance of follow-up checks was discussed.
[Examination and therapy in vaginal discharge and inflammations of the genitalia].
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[Experiences with Ambene in gynecological practice].
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[Analysis and biological studies on the N-acetyl-L-aspartate content of brain].
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MR imaging of calcified herniated thoracic disk.
The magnetic resonance findings in a 48-year-old woman with a calcified, herniated thoracic intervertebral disk at the T5-T6 level are reported. This patient had an 18 year history of spinal cord symptoms and signs, previously thought to be caused by multiple sclerosis (MS). Magnetic resonance was obtained for further evaluation of MS.
MRI of an aneurysm of the vein of Galen.
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