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The impact of meningeal dissemination in primary CNS lymphoma (PCNSL) is debated, and the reported frequency varies. We prospectively evaluated the diagnostic value of PCR in comparison with CSF cytomorphology and MRI for diagnosing meningeal dissemination in PCNSL.

The authors performed a comprehensive analysis of the functional outcome of 10 patients who had survived 5 years from a diagnosis of glioblastoma. Neurologic deficits were mild in most patients, but neuropsychological testing demonstrated cognitive deficits in all patients. Depression and anxiety were common. Although most patients thought that their social functioning and work ability were impaired, little reduction in overall quality of life was perceived.

Abstract

Purpose Focal ischemic stroke in neonates is a rare occurrence. Diagnosis with most imaging modalities is difficult, but necessary for initiating an anticoagulatory treatment. The purpose of this study was to evaluate the sensitivity of MRI sequences within the first 14 days of birth. Patients and methods Four patients with neonatal stroke presenting as seizures were examined using a standard MRI protocol including diffusion-weighted images (DWI) and magnetic resonance angiography (MRA) within 72 h of birth. The time between the onset of symptoms and MRI ranged from 6 h to 48 h. Follow-up examinations were performed on days 5 ( n=1), 7 ( n=2), and 14 ( n=1) for the control of a treatment with low-molecular heparin. Results Eight infarctions were detected in the four patients, 5 in the middle cerebral artery (MCA), three in the posterior cerebral artery (PCA) territory. All lesions were visible using DWI, four on T2-weighted images. Whereas in two patients small lesions contralateral to a large stroke were missed on T2-weighted images, the diagnosis would have been missed altogether without DWI in one patient. On follow-up, the visibility of the infarctions had declined using DWI after 5  days and the lesions were invisible after 1 week. Fourteen days after the stroke, an increased diffusion was detected in the infarcted brain tissue. By this time, all lesions were visible on T2-weighted images. Conclusion In neonates, infarcted brain tissue can be detected using DWI with high sensitivity during the first 2 days after stroke and before other sequences are diagnostic. However, the diffusion restriction does not persist beyond 1 week. After 5 days, diagnosis has to rest mainly on T2-weighted images.

Abstract.: The purpose of the present study was to analyse specific advantages of calculated parameter images and their limitations using an optimized echo-planar imaging (EPI) technique with high spatial and temporal resolution. Dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) was performed in 12 patients with cerebrovascular disease and in 13 patients with brain tumours. For MR imaging of cerebral perfusion an EPI sequence was developed which provides a temporal resolution of 0.68 s for three slices with a 128 × 128 image matrix. To evaluate DSC-MRI, the following parameter images were calculated pixelwise: (1) Maximum signal reduction (MSR); (2) maximum signal difference (ΔSR); (3) time-to-peak (Tp); and (4) integral of signal-intensity-time curve until Tp (SInt). The MSR maps were superior in the detection of acute infarctions and ΔSR maps in the delineation of vasogenic brain oedema. The time-to-peak (Tp) maps seemed to be highly sensitive in the detection of poststenotic malperfused brain areas (sensitivity 90 %). Hyperperfused areas of brain tumours were detectable down to a diameter of 1 cm with high sensitivity ( > 90 %). Distinct clinical and neuroradiological conditions revealed different suitabilities for the parameter images. The time-to-peak (Tp) maps may be an important advantage in the detection of poststenotic “areas at risk”, due to an improved temporal resolution using an EPI technique. With regard to spatial resolution, a matrix size of 128 × 128 is sufficient for all clinical conditions. According to our results, a further increase in matrix size would not improve the spatial resolution in DSC-MRI, since the degree of the vascularization of lesions and the susceptibility effect itself seem to be the limiting factors.

We examined 32 patients with intracranial tumors (17 meningiomas, 8 neuromas, 7 pituitary adenomas) by conventional and dynamic contrast-enhanced MRI. Our aim was to clarify whether the pathological dural contrast enhancement adjacent to meningiomas (the “dural tail”) is specific to meningiomas and, more important, whether it represents neoplastic dural infiltration or hypervascularization as a tumor accompanying reaction. A “dural tail” was found in 9 of 17 meningiomas. None of the other extra-axial tumours (neuromas, pituitary adenomas) showed comparable dural enhancement. Dynamic examinations with an ultrafast single slice imaging technique (snapshot-FLASH) after a bolus injection of contrast medium showed a “dural tail” in seven out of these nine meningiomas, while in two cases the “dural tail” turned out to be a cortical vein with a characteristic dynamic contrast enhancement pattern. In the dynamic study all seven “dural tails” were found to have earlier, steeper contrast enhancement than the corresponding tumours. All the tumours and part of the adjacent dura mater in four of the seven meningiomas with dural enhancement were examined histopathologically. In none of these four cases was neoplastic tissue found more than 2 mm away from the main tumour. The results strongly support the suggestion that the “dural tail” adjacent to meningiomas represents a hypervascular, non-neoplastic dural reaction.

Die Snapshot-Flash-Technik ermöglicht es, kernspintomographische Aufnahmen guter Qualität in einer Meßzeit von etwa einer Sekunde zu erhalten. Dadurch können auch bewegte Organe abgebildet werden, die bisher von der Untersuchung ausgeschlossen werden mußten. Die an einem Ganzkörpergerät erreichbare Zeitauflösung von 2 Sekunden für Aufnahmen mit einer 256*256 Bildmatrix ist ausreichend, um die peristaltische Bewegung von Magen und Darm zu verfolgen. Die erhaltene Bildfolge konnte in einen Videofilm übernommen und im Zeitraffer dargestellt werden.

The modification of reaction centers from Rhodobacter sphaeroidesby the introduction of pheophytins instead of bacteriopheophytins leads to interesting changes in the primary photosynthetic reaction: long-living populations of the excited electronic state of the special pair P* and the bacteriochlorophyll anion B−Ashow up. The data allow the determination of the energetics in the reaction center. The free energy of the first intermediate P+B−A, where the electron has reached the accessory bacteriochlorophyll BAlies ≈ 450 cm−1below the initially excited special pair P*.

This study addressed the use of 3D MR angiography with flip angles (FAs) linearly varying across the excitation volume in order to diminish spin saturation. The shape of the ramp profile was varied to optimize the method for different regions and pathological alterations. Radio frequency pulses with ramp-shaped excitation profiles were generated flow-compensated 3D-FISP sequence. With the use of ramp-shaped excitation profiles good results were obtained for intracranial arteries as well as for neck arteries (i.e. carotid and vertebral arteries) which were demonstrated in 6 healthy volunteers and in 5 patients with various stenoses and anomalies of the carotid and vertebral arteries. With this technique it was possible to use increased thicknesses of the excitation volume (slab) up to 256 mm. Ramp-shaped excitation pulses with linearly increasing FAs in main flow direction can provide improved contrast of the vessel parts located distally to the entry side of the slab. Although this method has no advantage concerning complex flow or other dephasing effects; its particular effectiveness lies in the reduction of spin saturation.

The authors investigated the applicability of Macdonald response criteria to patients with primary CNS lymphoma (PCNSL). Four of 68 patients with persisting contrast-enhancing lesions after primary therapy did not receive further therapy, and none showed tumor progression after up to 54 months. Because contrast enhancement may not necessarily indicate residual, biologically active lymphoma, the authors propose a modification of the Macdonald response criteria.

Summary: Methotrexate (MTX) is an indispensable antimetabolite for the treatment of oncological and immunological disorders in all age groups. Chronic leukoencephalopathy is a well know side effect of MTX, especially in conjunction with intrathecal administration and whole brain radio therapy. However, acute neurotoxicity with confusion, disorientation, seizures and focal deficits has also been reported. Because acute neurological symptoms in patients under chemotherapy for neoplastic disorders may have many reasons, MR-imaging is usually necessary to identify the underlying pathology. Apart from conventional sequences, diffusion-weighted imaging (DW-MRI) is frequently performed. We report on clinical and imaging findings of reversibly restricted diffusion in a patient with transient encephalopathy after intrathecal administration of MTX for recurrent acute lymphatic leukaemia.

We report a man with a ruptured intracranial dermoid cyst, suffering from headache, nausea, vomiting and a generalised seizure. MRI was performed before and 2 weeks after surgical resection. On T1-weighted images the tumour gave high signal, as did fatty material in the frontal and parietal brain sulci. Identification of this hyperintense material as lipids was possible by chemical-shift-selective 3 D gradient-echo imaging, which provided excellent contrast between the subarachnoid lipids and the adjacent normal brain, with a good spatial resolution. Possible complications of subarachnoid and intraventricular lipid particles after dermoid cyst rupture are discussed and the diagnostic value of 3 D chemical-shift-selective additional to conventional T1-weighted spin-echo images in identification of even small amounts of fat is emphasised.