Mitochondrial angiopathy in a family with MELAS.

A family with mitochondrial myopathy, encephalopathy, lactic acidosis and strokelike epidoses (MELAS) affecting mother, son and daughter is described. Biochemical studies on muscle biopsy specimen in one patient revealed NADH dehydrogenase (complex I) deficiency. A mitochondrial angiopathy could be demonstrated by brain and muscle biopsy. It is suggested that the mitochondrial angiopathy is the basic pathogenic mechanism of impaired cerebral circulation in MELAS.

Evolution of the infant spinal column: evaluation with MR imaging.

The appearance of the normal lumbar spinal column was examined in spinal magnetic resonance images obtained in 50 pediatric patients aged 2 years or less. The ossification centers of the developing vertebral bodies, the cartilage, and the disks were studied with a 1.5-T imager by using both short- and long-repetition-time spin-echo sequences. Many of the structures of the spine were noted to undergo dynamic changes in appearance, both in signal intensity and in morphologic characteristics, with growth. The vertebrae and cartilage, especially, transform markedly in infancy and proceed through three characteristic stages of evolution. Stage I, from birth to 1 month of age, is characterized by markedly hypointense ossification centers and hyperintense, prominent cartilage. Stage II, from approximately 1 to 6 months of age, is characterized by increasing signal intensity in the ossification centers, progressing from the endplates in, and decreasing prominence of the cartilage, Stage III, from approximately 7 months of age on, is characterized by increasingly rectangular and centrally intense vertebral bodies and diminishing cartilage. The variability of the signal intensities, with that of muscle used as the standard, and morphologic characteristics of different components of the spine at different stages of development can create significant confusion. Careful analysis, however, permits one to follow the evolution of the lumbar spine and to date it on the basis of its appearance.

Developing spinal column: gadolinium-enhanced MR imaging.

Enhancement characteristics of the normally developing spinal column were examined in magnetic resonance (MR) images obtained in 58 children aged 7 days to 9 years. With a 1.5-T imager, short-repetition-time spin-echo images were obtained before and after the administration of 0.1 mmol/kg gadopentetate dimeglumine. Enhancement of normal bone marrow was seen in all patients aged less than 7 years; it was marked only in patients aged less than 2 years. Enhancement of normal cartilage, seen in all patients aged less than 1 1/2 years, may be the most striking feature of enhanced MR images of the infant spine. Enhancement of both bone marrow and cartilage in children appears to be due to the unusual prominence of vasculature, associated with permeability of the capillary endothelium and a plentiful extravascular space. Although marked and diffuse enhancement of vertebral bodies in adults is often thought to indicate a pathologic marrow state, caution must be used before the same criteria are applied to children.

Retrobulbar cysts in Aicardi's syndrome.

Case report of a four-year-old girl with Aicardi's syndrome diagnosed from the triad: absence of the corpus callosum, focal seizures, and chorioretinal lacunae. In addition, MR scans and orbital ultrasonography detected retrobulbar cysts behind the right microphthalmic eye not described so far. Analyzing the histological data from two previous reports, it becomes likely that the cysts have formed from abnormal migration of neuroretinal tissue through the border of the optic disc coloboma that was also present. This pathomechanism is also known in isolated colobomatous microphthalmos in which cysts may occur.

The Dandy-Walker syndrome.

Ten cases of the Dandy-Walker syndrome are presented. The clinical manifestations are analyzed. Almost 80 percent of these children had associated anomalies. The characteristic findings are based on the magnetic resonance image scan. Satisfactory treatment of our patients had mostly consisted in shunting the lateral ventricular system to the peritoneum. The incidence of the complications was high.

Comparison of plain and Gd-DTPA-enhanced MR-imaging in children.

40 children and adolescents (aged 1-16 years) were examined by MRI at 1.0 T. Gd-DTPA was given intravenously at a dose of 0.1 mmol/kg body weight. In all cases T1-weighted SE sequences were used to demonstrate contrast enhancement. No adverse effects were seen. 30 patients had one or more lesions; in 20 patients contrast enhancement was seen. In 4 cases lesions were not observed by plain MRI and could only be detected after Gd-DTPA. In addition, contrast enhancement provided additional information about the differentiation of lesion from edema or necrosis in 13 patients. Normal brain matter did not show any changes in signal intensity. However, an age-dependent signal increase was found in the normal vertebral bone marrow in all children. Gd-DTPA should be used as a supplementary examination whenever a tumor or an infectious disease of the CNS is suspected and plain MRI is normal, or when origin and extent of a lesion cannot be adequately defined with plain MRI.

[The value of magnetic resonance tomography during radiotherapy of childhood tumors in the posterior fossa and the pineal region]. / Der Wert der Kernspintomographie bei der Strahlen-therapie kindlicher Tumoren der hinteren Schädelgrube und der Pinealisregion.

MRT is a highly sensitive method for the diagnosis of childhood tumours in the posterior fossa. Since it demonstrates tumour extent better than does CT, MRT is the method of choice for radiotherapy planning. The result of treatment can be judged morphologically and by measuring relaxation times. Changes due to treatment can be recognised more easily than by CT. A disadvantage of MRT is lack of specificity, since various processes may lead to an equal increase in T1 and T2 times.

[Anesthesia for magnetic resonance tomography]. / Anaesthesie zur Magnetresonanz-Tomographie.

Monitoring of the vital signs and the possibility of respiratory support are necessary conditions for the application of magnetic resonance imaging to infants and geriatric patients as well as during intensive care therapy. Since April 1986, 73 patients have been scanned under general anesthesia with controlled artificial ventilation in the Grosshadern University Hospital. For the first time, the ventilator could be placed in the vicinity of the magnetic resonance imaging scanner. With this system, the anesthesiologist is able to inspect the patient, ventilator, and monitoring unit from one place in the examination room.

[Value of conventional x-ray diagnosis and computerized tomography in the detection of Hill-Sachs defects and bony Bankart lesions in recurrent shoulder dislocations]. / Wertigkeit von konventioneller Röntgendiagnostik und Computertomographie im Nachweis von Hill-Sachs-Defekten und knöchernen Bankart-Läsionen bei rezidivierender Schultergelenkluxation.

Forty patients with anterior dislocation of the shoulder were examined in order to demonstrate Hill-Sachs defects and bony Bankart lesions. All patients had conventional radiographs of the shoulder in two planes, special views according to Hermodsson and Bernageau and CT. The examinations were evaluated by three observers. CT was regarded as the gold standard. Sensitivity for demonstrating Hill-Sachs defects for the standard views was 45% and for the Hermodsson views was 76%. For demonstrating Bankart lesions, standard views had a sensitivity of 37% and the Bernageau view 64%. Computed tomography was markedly superior to the standard and the special views, both for demonstrating the lesions and the agreement between various observers.

Magnetic resonance imaging of normal and pathological white matter maturation.

Fifty children between 3 months postnatal and 16 years of age were examined by means of a 1.5 T superconductive magnet, run at 0.35 and 1.0 T. The myelination was studied qualitatively and quantitatively (relaxation times, proton densities, image contrast). With increasing age, a decrease of T1 and proton density of white matter was found, which was complete at one year of age. In regions with a slow progression of myelination, gray/white matter contrast showed an increase up to the end of the first decade. Pathological white matter maturation was diagnosed either as an abnormal transformation of myelin (characterized by abnormal relaxation values), or as a deficient or delayed myelin formation (in comparison with age-matched controls).

Magnetic resonance imaging in children suffering from spina bifida.

22 children with myelomeningocele (MMC) were examined by magnetic resonance imaging (MRI). After operative closure a tethered cord was found in 78% of the patients. A primary tethered cord was detected in all patients where a lipomyelomeningocele had not been operated on yet. Additional malformations shown by MRI were hydromyelia and diastematomyelia. No correlation could be found between the degree of morphologic changes and the clinical course. In covered MMCs, MRI investigation is recommended as method of choice before operation. After operative closure a control-MRI should be performed after three months. If there are no pathological findings, further follow-up should be done by ultrasound investigation twice a year.

[Magnetic resonance imaging in craniopharyngiomas. The differential diagnosis of cystic intra- and suprasellar space-occupying lesions]. / Kernspintomographie bei Kraniopharyngeomen. Zur Differentialdiagnose zystischer intra- und suprasellärer Raumforderungen.

Seven patients with confirmed craniopharyngiomas were examined via magnetic resonance imaging. The various tumour components (whether solid, cystic or calcified) were evaluated separately. Three types of cysts were observed that can be distinguished by their signal intensity in various pulse sequences. This could be explained largely by an analysis of the T1 and T2 image contrast. The reason for the various types of cysts is determined by their cholesterol content. MR imaging is not as useful as CT for demonstrating the solid and calcified portions of the tumour and this reduces its value in diagnosing the type of tumour. Against that, it is superior with regard to separating the tumour from its neighbouring structures. The differential diagnosis, which must be considered in using MR, is summarised in a table at the end of the paper.

[Abnormalities of the brain in childhood in nuclear magnetic tomography]. / Fehlbildungen des kindlichen Gehirns im Kernspintomogramm.

25 of about 300 infants and children, who had been examined by magnetic resonance imaging since 1984, had a congenital malformation of the brain. Cystic malformations (e.g. arachnoid cysts) were the most frequent lesion. Other findings were: Arnold-Chiari malformation, septo-optic dysplasia, Dandy-Walker syndrome, agenesis of the corpus callosum, migration disorders. The multiplanar slice orientation and the good tissue contrast in magnetic resonance imaging supplied a clear diagnosis in all cases. Compared with other imaging modalities (CT, ultrasonography) the depiction of the morphology was superior in MR imaging in most cases.

[The contrast to noise ratio as a measure of tissue contrast in nuclear magnetic resonance tomography]. / Das Kontrastrauschverhältnis als Mass für den Gewebekontrast in der Kernspintomographie.

The contrast-to-noise ratio, known from the theory of imaging methods, is applied to magnetic resonance imaging. This ratio is proportional to the product of relative image contrast and the signal-to-noise ratio. After predetermining all intrinsic (T1 and T2 times, proton density) and extrinsic (pulse sequence, layer thickness, number of averagings) parameters, the signal-to-noise and contrast-to-noise ratio can be computed to a proportionality constant for all possible pulse sequences. Studies in six voluntary test subjects and 11 patients with a 0.35 T-unit showed that the measured values for the signal-to-noise ratio and the contrast-to-noise ratio are in good agreement with the computed values. The contrast between gray and white brain matter was used as an example for this. The method is applied in order to gain a better understanding of tissue contrast. However, by using diagrams it can be particularly useful for determining the optimal pulse sequences for answering particular clinical questions. It should thus be possible to enhance the effectiveness of magnetic resonance imaging considerably.

[Clinical significance of nuclear magnetic resonance tomography in urology. Initial experiences]. / Klinische Bedeutung der Kernspin-Tomographie in der Urologie. Erste Erfahrungen.

NMR tomography, which is based on nuclear magnetic resonance, enables the production of sectional images of the human body without ionising radiation. In particular, the field of urology places great hopes on this new procedures, since the contrast in soft tissue is considerably better than that of computer tomography. Our first clinical results confirm the advantages of the soft tissue differentiation as well as the possibility to judge the large vessels safely and simultaneously without contrast medium, which is advantageous in the detection of tumours in the retroperitoneum and in the region of the kidneys. An improvement of the preoperative staging of urological tumours can be achieved by means of primary three-dimensional images. Only after several years of experience with NMR tomography and all its variations will it be able to evaluate properly, to what extent clinically relevant diagnostic possibilities are offered by the analysis of relaxation values.

Changes in extracellular potassium and calcium in rat cerebellar cortex related to local inhibition of the sodium pump.

Extracellular K+, Ca2+, and Na+ ([K+]e, [Ca2+]e, [Na+]e) were recorded with ion selective microelectrodes in the cerebellar cortex of urethane-anesthetized rats. Superfusion of the cerebellum with artificial cerebrospinal fluid containing K-strophanthidin (10(-6)-10(-4) mol/l) or other cardioactive steroids, known to be inhibitors of the sodium/potassium pump, had the following effects: elevation of resting [K+]e, reduction of poststimulus K+-undershoots, decrease of resting [Ca2+]e and [Na+]e. For instance, at 3 X 10(-5) mol/l K-strophanthidin within the superfusion solution (the unknown intracerebellar concentration being certainly much smaller), [K+]e was elevated up to 130% and [Ca2+]e reduced to 70% of their resting values. Iontophoretic K+-pulses were enhanced in amplitude at the same time. Control experiments with iontophoretic TMA application demonstrated that the glycoside effects were not due (or in higher concentrations only partly due) to shrinkage of the extracellular fluid volume. When tetrodotoxin (10(-7) mol/l) or Mn2+ (1-3 mmol/l) were additionally superfused, K-strophanthidin effects were qualitatively similar, though quantitatively smaller. This indicates that part of the effects were indirect via neuronal activity evoked by the blockade of the sodium pump. The experiments show that reduction of sodium pump activity in cerebellar cortex has rapid and serious consequences on the distribution of potassium and calcium in the extracellular space, resulting in an alteration of neuronal circuit excitability.