Michael Just

Cerebral and spinal MR-findings in patients with postrepair myelomeningocele.

In 114 patients with postrepair myelomeningocele MRI of the spine was performed. Tethered cord (89%) and associated malformations (syrinx, lipoma etc.) (33%) were the most important findings. Additional MRI scans of the head (44 patients) revealed numerous further anomalies. Arnold Chiari malformation was found in 76% of the patients (ACM I: 32%, ACM II: 44%). In the ACM II group compression of lower cranial nerves, brain stem, and cerebellum can lead to considerable neurologic symptoms. Therefore in patients with progressive neurologic dysfunction a complete investigation of the whole spine and brain is necessary. MRI proves to be the diagnostic procedure of choice in patients with dysraphic myelodysplasia.

MRI-assisted radiation therapy planning of brain tumors-clinical experiences in 17 patients

A new and simple method for precise determination of lateral opposed treatment portals was developed and used in 17 patients. Compared to CT, MRI led to significant changes of portals in 59% (10/17) of cases. Individual shielding blocks could be precisely designed by use of our new method. MRI is the procedure of choice in local radiation therapy planning of brain tumors.

MRI of Listeria rhombencephalitis

SummaryA case of Listeria rhombencephalitis in a patient, who was evaluated by MRI, is reported. MRI showed areas of high signal intensity on T2-weighted images in the rhombencephalon and confirmed the clinical diagnosis of a brainstem affection by Listeria monocytogenes.

Errors in T1-determination using multislice technique and Gaussian slice profiles.

Multislice SE- or IR-sequences with different TR- and T1-times, respectively, are often used, to determine T1- and T2-values for tissue characterisation. To investigate the perturbating influence of the sequential excitation in multislice technique, we measured the signal intensities and calculated the T1-values of phantoms as a function of gap widths between neighboured slices. Phantoms contained fluids of different T1. We found a strong dependence of signal intensities and therefore of calculated T1-values on the gap width, when a T1/TR-ratio of more than 0.3-0.4 was reached. T1-values are considerably overestimated in this case, whereas T2-values are not influenced by the sequential excitation. We conclude that reliable T1-measurements necessitate a large spacing of more than 1 slice thickness between adjacent slices.

Magnetic resonance imaging of postrepair-myelomeningocele--findings in 31 children and adolescents.

Magnetic resonance imaging has clearly demonstrated its efficacy in the diagnosis of pathological processes in the C.N.S. We examined 31 children who had undergone plastic closure of myelomeningocele a few days post partum. We could show that a high percentage of the patients (89%) presented the pathological anatomy of a tethered spinal cord; clinical symptoms of the tethered spinal cord syndrome, i.e. progressive neurological symptoms, however, are rarely observed. Possible revision of neurosurgical treatment of MMC is discussed.

Magnetic resonance imaging in infections of the brain: Findings in tuberculosis, listeriosis, toxoplasmosis, subacute sclerosing panencephalitis, and multiple sclerosis

A total of 6 patients with various inflammatory brain diseases were investigated by MRI. Typical diagnostic criteria like signal intensity, location, and morphology of the lesions are presented. MRI proves to be a highly sensitive method to detect encephalitic foci, which, however, suffers from a low specificity. Therefore additional informations like case history, clinical findings, and serological data have to be considered to find the correct diagnosis.

Magnetic resonance imaging in primary cerebral neuroblastoma

A 21-year-old man presented with clinical signs of elevated intracranial pressure. MRI (0.28T ~) revealed a large intraventricular tumor predominantly located in the lateral ventricles. The tumor showed similar signal intensities to gray matter on T1and PD-weighted scans. However T2-time was markedly prolonged giving excellent contrast to normal brain tissue on T2-weighted images (Fig, 1 a). Injection of Gd-DTPA (0.1 mmol/kg) resulted in a strong enhancement on Tl-weighted scans (Fig. 1 b). After total removal of the neoplasm histopathological investigation revealed a highly cellular undifferentiated tumor with multifocal pseudocystic degeneration. Ira: munocytochemical stainings for neurofilaments and keratin were negative. Some cells showed GFAPand vimentin-positive reaction. The most striking finding was a positive reaction for synaptophysin. This led to the diagnosis of neuroblastoma. An 24-month follow up revealed neither local tumor recurrence nor signs of a primary extracerebral tumor. Discussion

Long-term follow-up of children with magnetic resonance imaging and ultrasound after treatment of brain tumors

This paper compares the results of MRI and US follow-up examinations of 46 children who had undergone surgery for brain tumors. The cases included 42 posterior fossa tumors, 3 supratentorial tumors and 1 upper cervical spinal cord tumor. US examination proved to be less specific and sensitive than MRI. However, when a “bone window” is available, US is, because of the ease of its application, better suited for frequent routine examinations. Long-term follow-up should, therefore, consist of frequent regular US examinations combined with yearly MRI examinations.