Werner Wichmann

Conservative Treatment of Patients with Acoustic Tumors

Seventy of 178 patients with acoustic tumors initially were treated conservatively and have been followed up for an average of 26 +/- 2 months. The tumor size was determined by the mean maximum anteroposterior and mediolateral diameters, using computed tomographic or magnetic resonance imaging scans obtained sequentially throughout the follow-up period. The average tumor growth was 1.6 +/- 0.4 mm the 1st year, and 1.9 +/- 1.0 mm the 2nd year (range, -2 to 17 mm/y): 4 tumors showed apparent regression, 28 (40%) had no detectable growth, and 37 (53%) exhibited growth (average, 3.8 +/- 1.2 mm/y). Within individual patients, the tumor growth rate determined during the 1st year of follow-up was predictive of tumor growth rate determined during the following year. Rapid tumor growth or clinical deterioration in 9 of the 70 patients (13%) who initially were treated conservatively necessitated subsequent surgery an average of 14 +/- 5 months after the patient was initially seen. This group had a larger initial tumor size (27.0 +/- 3.4 mm vs. 21.3 +/- 0.9 mm, P less than 0.05), and a faster 1-year growth rate (7.9 +/- 2.3 mm/y vs. 1.3 +/- 0.3 mm/y, P less than 0.05) than the 61 patients who did not require surgery. Two patients, however, experienced neurological deterioration that required surgery, even though there was no tumor growth. The high incidence of acoustic tumors with no detectable growth or apparent spontaneous regression must be taken into account when evaluating the indications for surgery and the efficacy of radiotherapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Age distribution and iron dependency of the T2 relaxation time in the globus pallidus and putamen

SummaryHeavily T2-weighted spin echo sequences of the brain show age-dependent low signal intensity in many extrapyramidal nuclei. Although it has been suggested that this low intensity results from non-haem iron, the specific influence of non-haem iron on the T2 relaxation time has not been quantified and remains controversial. The T2 relaxation times of the globus pallidus and putamen were measured from MRI at 1.5T in 27 healthy patients, by using a mathematical model. They were then plotted as a function of age and compared to the curve of age-dependent iron concentration determined post mortem. The curves of T2 relaxation time in the basal ganglia are congruent with published curves of iron concentration, indicating a high probability that the changes in T2 relaxation times and the low signal in the basal ganglia result from the local, age-dependent iron deposition. Individual measurements of T2 relaxation time show less variation before than after 45 years of age, indicating the influence of a second, more individual factor.

Relationships between MR-imaged total amount of tissue removed, resection scores of specific mediobasal limbic subcompartments and clinical outcome following selective amygdalohippocampectomy

Of 204 patients who underwent a selective amygdalohippocampectomy at our hospital, we studied 30 in whom special pre- and postoperative MR imaging was carried out and who were followed up for at least 1 year postoperatively. We measured the total size of the resection and the extent to which the following specific mediobasal temporal lobe structures had been removed: amygdala, hippocampus, pes hippocampi, dentate gyrus, parahippocampal gyrus, uncus and subiculum. Postoperative seizure control was correlated with the overall size of the resection as well as with the resection scores of the above mentioned limbic subcompartments. The mean size of the removed tissue was 7.2 cm3 (range: 2.1-17.7). The mean resection scores of the limbic subcompartments (in percentages) are: amygdala 92%, hippocampus 46%, pes hippocampi 92%, dentate gyrus 45%, parahippocampal gyrus 32%, uncus 92%, subiculum 40%. Although a small resection did not exclude a good outcome, the general tendency was that a better outcome was obtained from a larger resection. With regard to the resection scores of the limbic subcompartments, a positive correlation emerged between good postoperative outcome and the radicality of the removal of the parahippocampal gyrus (and the subiculum, which has been evaluated separately). These findings support our previously formulated amplifier hypothesis for the parahippocampal gyrus.

NEURORADIOLOGY OF CENTRAL NEUROCYTOMA

SummaryCentral neurocytomas (CN) are rare, usually benign cerebral intraventricular neuroepithelial tumors, which occur in adult patients. Retrospective evaluation of the CT- and MRI-findings in eight cases as well as review of the cases reported in the literature showed that CN usually presents as a primarily slightly hyperdense and/or hyperintense mass within the body of the lateral ventricle with moderate contrast enhancement. The majority of tumors contain both multiple small cysts and calcifications and exhibit a characteristic broad based attachment to the superolateral ventricular wall. We conclude that these criteria appear to be reliable to exclude other intraventricular tumors such as astrocytoma, giant cell astrocytoma, ependymoma, subependymoma, intraventricular oligodendroglioma and meningioma. Preoperative diagnosis of CN may prove of value for planning therapy, because this tumor type seems to have a better prognosis than other intraventricular tumors.

Blood–brain-barrier Disruption in Acute Wernicke Encephalopathy: Mr Findings

The clinical and MR features of an alcoholic woman with Wernicke encephalopathy are reported. During the acute stage Gd-diethylenetriamine pentaacetic acid enhanced MR revealed damage of the blood-brain barrier bilaterally and symmetrically adjacent to the third ventricle, cerebral aqueduct, and fourth ventricle. The enhancement disappeared after successful thiamine therapy, as demonstrated in a repeat postcontrast MR 1 week later.

Electrophysiology in the locked-in-syndrome

We investigated five patients with a locked-in-syndrome (LIS) and reported the clinical, electrophysiologic, neuroradiologic, and neuropathologic findings. EEG reactivity was present in two and absent in three cases. Somatosensory evoked potentials (SEP) varied from unilaterally normal to bilaterally absent. We conclude that there is no specific pattern of SEP abnormality characteristic of LIS and that EEG reactivity cannot be taken as a sole measure of consciousness. NEUROLOGY 1996;46: 1092-1101

3D T2-weighted fast spin-echo MRI sialography of the parotid gland

Abstract The diagnostic value of 3D T2-weighted MRI sialography and 2D T2-weighted fast spin-echo (FSE) images for delineation of the normal duct system and characterisation of parotid gland duct pathology was compared in a prospective study. We studied eight healthy volunteers and 18 patients with pathology of the parotid gland (tumours in 3, sialolithiasis in 6, Sjögrens disease in 4, recurrent or chronic parotitis in 4, post-traumatic stricture of the main parotid duct in 1). A heavily T2-weighted 3D FSE sequence was compared with a conventional 2D T2-weighted FSE sequence. The normal main parotid duct was always visible on 3D sialography and seen in 68 % of the 2D T2-weighted FSE studies. The diagnostic reliability of both sequences for diagnosis of luminal concretions in sialolithiasis and dilatation of the duct in duct stricture or chronic parotitis was equal, although slight intraglandular dilatation was appreciated only on 3D sialography. Extraductal pathology resulting in obstruction or displacement of ducts was better characterised on 2D T2-weighted images. However, 3D MRI sialography offered the advantage of postprocessing with overview images and multiple maximum-intensity projection images in any plane.

Pelizaeus-Merzbacher disease: identification of heterozygotes with magnetic resonance imaging?

We report magnetic resonance imaging (MRI) findings in two obligate and four facultative carriers for the classical X-linked form of Pelizaeus-Merzbacher disease (PMD). In T2-weighted images MR revealed bilateral multiple areas with signal hyperintensity in the periventricular and subcortical white matter in five women. Until suitable and closely linked DNA probes are found for heterozygote determination, MRI may represent a suitable means for carrier detection in individuals at risk in PMD families.SummaryWe report magnetic resonance imaging (MRI) findings in two obligate and four facultative carriers for the “classical” X-linked from of Pelizaeus-Merzbacher disease (PMD). In T2-weigthed images MR revealed bilateral multiple areas with signal hyperintensity in the periventricular and subcortical white matter in five women. Until suitable and closely linked DNA probes are found for heterozygote determination, MRI may represent a suitable means for carrier detection in individuals at risk in PMD families.

The Missing Temporal Crescent

PURPOSEnWe studied clinically the representation of the monocular temporal crescent in the human visual cortex and noted the importance of using the perimetric techniques best suited to detect this visual field defect and to study patients in whom the temporal crescent is missing.nnnMETHODSnGoldmann perimetry and high-resolution magnetic resonance imaging were performed in two patients with vascular lesions located in the anterior striate cortex.nnnRESULTSnA monocular visual field defect, the missing temporal crescent, was found on the side contralateral to the lesion.nnnCONCLUSIONSnThe perimetric-magnetic resonance imaging correlation is in exquisite agreement with recent information about the representation of the visual field in the human primary visual cortex. Reports of this specific perimetric finding are rare, in part because of underdetection with currently used perimetric techniques that concentrate on the central 30 degrees of the visual field.

The cerebellar nodulus: Perceptual and ocular processing of graviceptive input

Current concepts postulate a decisive role of the cerebellar nodulus in the processing of otolith input. We hypothesized that nodular lesions abolish otolith‐perceptual integration, predicting alignment of perceived direction of earth vertical with the z‐axis of the head and not with gravity. In an 80‐year‐old patient with acute heminodular infarction, the subjective visual vertical deviated contralesionally by −21.1° when the patient was upright. After subtracting this offset, perceived vertical closely matched the patients head orientation when the patient was roll‐tilted. Otolith‐ocular reflexes remained normal. This is the first report on abolished earth verticality perception in heminodular stroke and underlines the importance of the nodulus in spatial orientation. Ann Neurol 2015;77:343–347