Megalencephalic leukoencephalopathy with subcortical cysts in an adult: quantitative proton MR spectroscopy and diffusion tensor MRI.

A 37-year-old macrocephalic woman was investigated for increasing gait disturbance due to longstanding spasticity and ataxia. MRI showed widespread bilateral increase in signal from cerebral white matter on T2-weighted images. Numerous subcortical cysts were visible in anterior-temporal and parietal regions. These clinical and neuroradiological features are those of megalencephalic leukoencephalopathy with subcortical cysts (MLC), a recently delineated white-matter disease with onset in childhood. Quantitative localised proton MR spectroscopy of white matter revealed marked reduction of N-acetylaspartate, creatine, and choline with normal values for myo-inositol, consistent with axonal loss and astrocytic proliferation. Diffusion tensor imaging showed an increased apparent diffusion coefficient and reduced anisotropy in affected white matter pointing to reduced cell density with an increased extracellular space. These findings are in line with histological changes alterations known to occur in MLC.

Medullomyoblastoma: a histological, immunohistochemical, ultrastructural and molecular genetic study.

Medullomyoblastoma is a rare variant of medulloblastoma containing myoblastic elements. A 9-year-old boy developed a cerebellar syndrome and signs of increased intracranial pressure, the cause of which was a tumor of the cerebellar vermis measuring 7 x 4.5 x 4.5 cm. Morphologically the tumor largely consisted of a medulloblastoma component but displayed glial, myoblastic and ganglionic differentiation on light microscopic, immunohistochemical and ultrastructural examination. The non-enhancing rim of the tumor on magnetic resonance imaging showed extensive ganglionic differentiation. The tumor did not express bcl-2, c-myc, or c-erb-B2 oncoproteins and was negative for the p53 gene product. On molecular genetic studies, the tumor did not show allelic loss on chromosome loci, frequently altered in medulloblastomas, such as 17p, 1q and 9q.

Proton magnetic resonance spectroscopy in patients with glial tumors: a multicenter study.

The authors represent a cooperative group of 15 institutions that examined the feasibility of using metabolic features observed in vivo with 1H-magnetic resonance (MR) spectroscopy to characterize brain tumors of the glial type. The institutions provided blinded, centralized MR spectroscopy data processing long with independent central review of MR spectroscopy voxel placement, composition and contamination by brain, histopathological typing using current World Health Organization criteria, and clinical data. Proton 1H-MR spectroscopy was performed using a spin-echo technique to obtain spectra from 8-cc voxels in the tumor and when feasible in the contralateral brain. Eighty-six cases were assessable, 41 of which had contralateral brain spectra. Glial tumors had significantly elevated intensities of choline signals, decreased intensities of creatine signals, and decreased intensities of N-acetylaspartate compared to brain. Choline signal intensities were highest in astrocytomas and anaplastic astrocytomas, and creatine signal intensities were lowest in glioblastomas. However, whether expressed relative to brain or as intratumoral ratios, these metabolic characteristics exhibited large variations within each subtype of glial tumor. The resulting overlaps precluded diagnostic accuracy in the distinction of low-and high-grade tumors. Although the extent of contamination of the 1H-MR spectroscopy voxel by brain had a marked effect on metabolite concentrations and ratios, selection of cases with minimal contamination did not reduce these overlaps. Thus, each type and grade of tumor is a metabolically hetero-geneous group. Lactate occurred infrequently and in all grades. Mobile lipids, on the other hand, occurred in 41% of high-grade tumors with higher mean amounts found in glioblastomas. This result, coupled with the recent demonstration that intratumoral mobile lipids correlate with microscopic tumor cell necrosis, leads to the hypothesis that mobile lipids observed in vivo in 1H-MR spectroscopy may correlate independently with prognosis of individual patients.

[Tumorous neurosarcoidosis--a rare manifestation of Boeck disease--3 cases and review of the literature]. / Die tumorbildende Neurosarkoidose--eine seltene Manifestation des Morbus Boeck--Drei Fälle und Literaturübersicht.

Neurosarcoidosis mimicking CNS tumours represents a rare manifestation of Schaumann's disease. The central or peripheral nervous system is clinically involved in 5% of sarcoidosis, basal parts of the brain being mainly affected by the inflammation. This location of the process causes basal meningitis with cranial nerve paresis as well as parenchymal granulomatosis around the third ventricle and hypophysis. Solid, space-occupying lesions rarely occur, evoking problems in the differentiation from cerebral tumours. We report three cases of neurosarcoidosis presenting as intracranial tumours, where a space-occupying lesion was the first of only manifestation of sarcoidosis. The lesions in our cases were found in parietal and parieto-occipital cortex and in the fourth ventricle and vermis cerebelli, respectively. These locations are unusual, since most of the reported cases were affecting the temporal lobe. We review the literature and discuss the role of neurosarcoidosis in the differential diagnosis of intracranial tumours.

MR imaging related to p.m. findings in angiodysgenetic myelomalacia. A case report.

In a 65-year-old patient with slowly progressive myelopathy of the lower spinal cord MRI revealed slight thickening of the conus medullaris and discrete serpiginous areas of low signal intensity in contact to the surface of the myelon. The T2-weighted axial images demonstrated a zone of high signal intensity within the center of the lumbosacral cord. These findings corresponded to the results of autopsy: cord enlargement, dilatation of wall thickened and partially thrombosed pial veins, edema, damage of the myelin sheath with development of foam cells, areas of hemorrhage and necrosis. Although myelography and spinal digital subtraction angiography had been normal in this case we assume that perhaps a spinal dural av-fistula may have been the cause of MR- and pathological findings which indicate an angiodysgenetic myelomalacia (Morbus Foix-Alajouanine). The pathogenesis of spinal dural av-fistulas is discussed in order to explain why angiography has been negative.

[Migration disorders of the brain--an evaluation of computed tomographic and magnetic resonance tomographic studies]. / Migrationsstörungen des Gehirns--eine Auswertung computertomographischer und kernspintomographischer Untersuchungen.

Twenty-eight patients with abnormalities of migration were examined with CT and MRI. Thirteen patients had heterotopia, ten patients had agyria/pachygyria, two with unilateral schizencephaly and three with hemimegalencephaly. MRI proved markedly superior because of its wider contrast range and its ability to obtain various imaging planes. The various conditions are described in detail.

[Magnetic resonance tomography of laminar heterotopia]. / Kernspintomographie bei laminärer Heterotopie.

In one baby and 2 infants who presented with psychomotor retardation and epilepsy laminar heterotopic grey matter was demonstrated via magnetic resonance imaging. Laminar heterotopia is a rare migrational disorder with bilateral symmetric ribbons of grey matter within the centrum semiovale, separated from ventricular walls and from obviously normal-sized cortex by broad layers of white matter. The heterotopic grey matter has a signal intensity which is isointense compared with that of normal cortex irrespective of image weighting. On account of this signal behaviour differentiation against other white matter diseases is easy. The knowledge of these pathognomonic findings facilitates correct diagnosis, especially during the first and the second year of life, when signal intensities of white and grey matter differ from normal findings because of the occasionally delayed myelination process. Therefore, further diagnostic procedures can be avoided and early counseling of parents is possible.

MRI diagnosis of aneurysmal bone cyst.

80-90% of individuals suffering from aneurysmal bone cyst (ABC) are children or adolescents. Primary ABC is a non-neoplastic lesion. Diagnostic assessment and detection of recurrence demands repeated plain x-rays or CT scans. These repeated radiographic examinations expose these young patients to large doses of ionizing radiation. Magnetic resonance imaging (MRI) is found to be an effective and reliable noninvasive technique for the diagnosis and follow-up controls of ABC.

Gadolinium-DTPA enhanced MR imaging of spinal dural arteriovenous fistulas.

To evaluate the role of magnetic resonance (MR) in the diagnosis of dural arteriovenous (AV) fistulas and the resulting myelopathy, the MR examinations of 11 patients with symptoms and signs of slowly progressive myelopathy of the lower spinal cord have been reviewed. Patients with intradural or extradural AV malformations were excluded. Six patients have been examined without the use of a contrast agent. The other five patients were studied prior and after intravenous administration of gadolinium-diethylenetriamine pentaacetic acid (DTPA). Serpentine linear areas of low signal due to flow void effects within the subdural space have been detected in seven patients. The T1-weighted sagittal images and T2-weighted sagittal and axial images demonstrated signal intensity changes within the center of the cord due to prolongation of T1 and T2 relaxation times. In addition, a relatively abrupt increase of the sagittal and transverse diameters of the lower thoracic cord was found in all cases. In nine patients T1-weighted, proton-density and T2-weighted sagittal images presented "blurred" margins of the lower thoracic cord. After intravenous administration of Gd-DTPA (0.1 mmol/kg), contrast enhancement was present not only within these vessels but also within the lower spinal cord. There was only slight enhancement of the cord immediately after injection of the contrast agent, but significant enhancement was observed 40-45 min later.

[Magnetic resonance tomography of the perineural cyst]. / Kernspintomographie der Perineuralzyste.

It may be difficult to differentiate between symptomatic perineural cysts, arachnoidal cysts, meningoceles, neurinomas and other cystic masses within the spinal canal and spinal foramina. Therefore the impact of MRI on the differential diagnosis of these lesions is discussed on the basis of 15 cases with perineural cysts, 1 case of an arachnoid cyst, 2 cases of meningoceles and 2 cases of neurinomas. The problem of fluid characterisation by the use of special MR measurements is emphasised.

[Role of nuclear magnetic resonance imaging in the diagnosis of monosymptomatic optic neuritis]. / Die Rolle der Kernspintomographie bei der Diagnose einer monosymptomatischen Neuritis nervi optici.

34 patients with monosymptomatic optic neuritis were examined ophthalmologically and by magnetic resonance imaging (MRI). In 18 patients subclinical lesions with a high MRI signal intensity were found. The distribution of these lesions was similar to that seen in multiple sclerosis. Neither the severity of the visual impairment nor the course of remission correlated to the MRI findings. Pathologic MRI findings were more common in patients aged over 27 than in younger patients (57% vs. 42%).

Magnetic resonance imaging (MRI) and high resolution computertomography (HRCT) in cochlear implant candidates.

Cochlear implant candidates must be thoroughly tested for their suitability pre-operatively. Electrical and electrophysiological tests as well as a psychological assessment are of fundamental importance in the selection process. The implantation of an intracochlear electrode requires specific information about the anatomy of the petrous bone and the endocochlear space. Such information can be obtained by using high resolution computed tomography (HRCT) or magnetic resonance imaging (MRI) using a surface coil. Over three years 438 patients were evaluated in our clinic as possible implant candidates. Out of these candidates 251 were evaluated using HRCT and 123 using MRI. In 39 (15.5%) cases we found bony abnormalities of the petrous bone using HRCT scans. 17 (13.8%) of the cases evaluated with MRI had no complete fluid filled spaces in the cochlea. Three patients who where identified as having ossified cochleas were subsequently implanted with an extracochlear device. MRI and HRCT have proved to be fundamental tools in determining patients suitable for implantation of an intracochlear electrode array.

[Attempt at preoperative differentiation of malignant melanoma of the choroid. A comparison of nuclear magnetic resonance tomography, ultrasound echography and histopathology]. / Versuch einer präoperativen Differenzierung des malignen Melanoms der Aderhaut. Ein Vergleich von Kernspintomographie, Ultraschallechographie und Histopathologie.

In a large choroidal melanoma (prominence 12 mm, volume approx. 1,900 mm3) diagnostic sonography revealed an unusual compartmentation, corresponding to the internal reflectivity of the tumor. When NMR imaging was performed, marked differences in signal behavior were seen between the tumor's center and its periphery. Histopathology revealed a highly pigmented spindle B melanoma containing an amelanotic island with signs of necrosis. The ultrasound pattern was explained on the basis of well known physical phenomena, whereas the NMR signals are still not fully understood.

Tuberous sclerosis: magnetic imaging of the brain.

The results of the magnetic resonance imaging of three patients with proven tuberous sclerosis will be discussed. Cortical tubers and subcortical areas of junctional dysmyelination can be demonstrated clearly by MRI, whereas small calcifications may be missed because of low contrast if the chosen slice thickness should be too large. It is suggested that MRI should be applied to those patients with suspected tuberous sclerosis, in which CT has failed to demonstrate typical subependymal calcifications and to those in which doubts about the definite diagnosis remain. This should be done in order to improve the accuracy of genetic counselling. It may be argued that all patients with tuberous sclerosis have to be referred to MRI, because transformation of subependymal nodules into diffusely infiltrating gliomas can be detected earlier if comparison with a former MRI study is possible.

Magnetic resonance imaging in lissencephaly.

In a patient with clinical manifestations suggestive of brain malformation, computer-assisted tomography (CT) showed lissencephaly: agyria, pachygyria, absent opercularization, and colpocephaly. The patient did not have seizures or a typical EEG of hypsarrhythmia. By magnetic resonance imaging (MRI), using a long inversion-recovery sequence, it was possible to verify the CT-findings and to demonstrate heterotopic grey matter and missing claustrum. By MRI it was much easier to estimate the altered ratio of grey and white matter. High grey-white matter contrast of inversion-recovery scans and the possibility of imaging the brain in sagittal, coronal and transverse planes make MRI the method of choice for the evaluation of lissencephaly and other brain malformations. In this case it helped to verify lissencephaly as one aspect of an unknown clinical entity of type-I-lissencephaly, defective structure of lymphatic nodes, a polyarthritis-like clinical picture, hypodontia, and flaring of the ribs.

Dynamic MR imaging: a further possibility for characterizing CNS lesions.

To improve the specificity of MR imaging, 45 patients with different lesions in the CNS were studied with gadolinium-DTPA from June to December 1985. With a dosage of 0.2 ml/kg body weight, no adverse effects were seen. Seventeen of these patients were also studied with dynamic MR imaging, using a spin-echo sequence of TR = 100 msec and TE = 30 msec and a display matrix of 128(2). Four parameters were determined and compared with histologic findings: the time to peak of signal intensity, the ascent to peak of signal intensity, the height of peak of signal intensity, and the percentage of peak of signal intensity at the end of measurement. In this small series, arteriovenous malformations had a short time to peak and a steep ascent to peak as compared with tumors. Gliomas had a slow ascent to peak and usually a longer time to peak as compared with tumors of mesodermal origin. Paragliomas according to Zülch's classification had a steeper ascent to peak than gliomas. Dynamic MR with gadolinium-DTPA may lead to further information about lesions in the CNS, as the ascent to peak parameter seems helpful in discriminating among different lesions.

Magnetic resonance imaging in vascular malformations: studies with and without gadolinium-DTPA.

MRI and gadolinium-DTPA enhanced dynamic MRI increase the information available for and from diagnosis of vascular malformations since it appears possible to obtain nearly specific information about these lesions. Further investigations are needed with fast imaging, flow imaging, and MR substraction angiography to obtain information similar to that obtained by angiography and CT. The value of X-ray CT for the diagnosis of vascular malformations seems to be inferior to MRI since MRI can delineate vessels and flow better and also allows direct multiplanar imaging.

[Measuring the thickness of facial soft tissues using nuclear magnetic resonance tomography for the purpose of identification]. / Dickenmessung der Gesichtsweichteile mit Hilfe der Kernspin-Tomographie zum Zwecke der Identifizierung.

Nuclear spin tomography since its beginnings in the seventies has steadily gained in importance as a method of examination in medical diagnostics as it produces a picture. In the field of forensic medicine the NMR technique as used for anatomic-anthropologic issues attempting to identify skulls this is a valuable supplement to an extension of the existing methods of investigation. The results of a measurement of the thickness of soft facial tissue in a live test person is shown as compared to measures obtained by sonography.