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Magnetic resonance imaging (MRI) is the method of choice for the diagnosis of sphenoid wing meningiomas. The close relationship situation to vascular and neural structures especially at the skull base can best be assessed with MRI. With a typical configuration and extent the diagnosis of meningiomas can be made on visual examination and MRI is also the standard imaging technique for follow-up of treated and asymptomatic meningiomas. In the preoperative evaluation, computed tomography is a complementary examination technique which can demonstrate the extent and type of bone involvement more precisely. This additional information is important to differentiate meningiomas from differential diagnoses, such as metastases, sarcomas, and primary osseous changes, such as fibrous dysplasia or Paget's disease. Positron emission tomography computed tomography (PET-CT) and PET-MRI are also supplemental examination procedures which can be used for determining tumor volume before a planned radiotherapy and can be helpful in the diagnosis of atypical meningiomas due to the selective binding of the tracer DOTATOC. Conventional angiography is only rarely used preoperatively.

Magnetic resonance imaging has become the most important tomographic imaging technique in neuro-ophthalmological diagnostics. A short introduction to the basic physical principles of MRI followed by a glossary summarising the relevant sequences used in neuro-ophthalmologic diagnostics provides an insight into this complex method. Differences and specific diagnostic values of every sequence are demonstrated with the help of sample images., (© Georg Thieme Verlag KG Stuttgart · New York.)

Objective: To examine the time course of signal changes in diffusion-weighted magnetic resonance imaging (DW-MRI) and T2-weighted MRI in a case of cerebral infarction in the posterior circulation territory., Materials and Methods: Diffusion- and T2-weighted MRI and comparison of signal changes in these sequences at 4 h, 1 day and 4 days after the onset of clinical symptoms caused by acute thalamo-mesencephalic infarction., Results: Four hours after the onset of symptoms, signal changes in DW-MRI revealed an infarction in the territory of the posterior perforating thalamic artery, whereas no signal changes were detected in T2-weighted MRI. In follow-up MRI 1 and 4 days after infarction, however, a marked hyperintensity matching the location of the diffusion deficit could be identified in T2 images., Conclusion: Signal changes in DW-MRI precede T2 hyperintensity after infarction in the posterior circulation territory after hemispheric infarction.

Medulloblastoma is the most frequent paediatric malignant brain tumour. The purpose of this study was to define imaging characteristics and contrast uptake patterns of primary and recurrent medulloblastoma using MRI. The MRI examinations of 17 histologically proven cases of medulloblastoma diagnosed in our institution (13 males and 4 females; mean age 13 years, 7 months) were reviewed in retrospect. Only patients with pre-treatment and follow-up examinations including T2-weighted images (fluid-attenuated inversion recovery or turbo spin echo) and T1-weighted images after contrast injection (0.1 mmol/kg Gd-DTPA) were included in this study. Whereas 6 of 7 tumours ( n=17) were hyperintense on T2-weighted images, contrast enhancement was detected in 13 patients. Fifteen tumours occurred in the cerebellar vermis, two were located in the cerebellar hemispheres. Mean size at the time of presentation was 30.1 mm. All patients presented with some extent of an occlusive hydrocephalus. Local recurrent tumour or metastases were seen in 6 patients (3 months to 7 years, mean age 2.5 years). Whereas the T2 signal intensity of recurrent tumour or subarachnoidal metastases resembled the primary neoplasms, the contrast uptake tended to be less pronounced ( n=3) or was completely absent ( n=2); thus, suggestive signs of primary medulloblastoma are location in the vermis, hyperintensity on T2-weighted images and hydrocephalus. The amount of contrast enhancement is variable and nonspecific. Secondary medulloblastoma manifestation is characterized by T2 hyperintensity but not by contrast uptake.

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Copyright of Der Ophthalmologe is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)