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Lymphomatosis cerebri (LC) is a rare variant of primary central nervous system lymphoma (PCNSL). Clinically, the disease typically presents with a rapidly progressive dementia and unsteadiness of gait. Its presentation on cerebral MRI, which is characterised by diffuse leukoencephalopathy without contrast enhancement, often causes diagnostic confusion1 with suspected diagnoses ranging from Binswanger's disease to leukoencephalopathy or encephalomyelitis. Here we report a patient with subacute dementia and diffuse bilateral white matter changes in the cerebral hemispheres and additional involvement of the brainstem, basal ganglia and thalamus on MRI. Initially, she was considered to suffer from an autoimmune encephalitis, transiently responded to immunosuppression but then developed multiple solid appearing cerebral lymphomas.

Objective: Neurofibromatosis type1 (NF1) is associated with cognitive and motor deficits whose pathogenesis is not well understood. 18F-Flurodeoxyglucose positron emission tomography (FDG PET) might be used to investigate putative functional correlates in the brain., Methods: Whole-body FDG PET including the brain had been performed in 29 NF1 patients suspected for malignant peripheral nerve sheath tumours (20 females, nine males, age 31.2+/-11.8 years). Twenty-nine age-matched and sex-matched subjects without evidence of neurological/psychiatric disease in whom FDG PET had been performed for NF1-unrelated oncological indication served as controls. Individual brain FDG retention images were stereotactically normalized and scaled to a common median retention value within the brain. Scaled FDG retention was compared between the NF1 group and the control group on a voxel-by-voxel base using ANCOVA in SPM2 with the FDG uptake period as covariate. The corrected significance level alpha=0.05 was used. Voxel-based analysis was complemented by volume of interest (VOI)-based analysis using predefined standard VOIs., Results: The voxel-based group comparison revealed a significant reduction of scaled FDG retention in the thalamus of the NF1 subjects within a cluster of 11.6 ml. There were no further significant effects, neither hypo-retention nor hyper-retention. Reduction of relative FDG retention in the thalamus in the NF1 subjects was confirmed by VOI analysis. The magnitude of the reduction was about 8%., Conclusions: The thalamus appears to be affected in adults with NF1. The observed magnitude of the reduction of scaled thalamic FDG retention in adults is smaller than previously reported in children. This may be consistent with a stabilization of the disease process with age.

Purpose: Visual reading of [(123)I]IBZM SPECT scans depends on the experience of the interpreter. Therefore, semi-quantification of striatal IBZM uptake is commonly considered mandatory. However, semi-quantification is time consuming and prone to error, particularly if the volumes of interest (VOIs) are positioned manually. Therefore, the present paper proposes a new software tool ("IBZM tool") for fully automated and standardised processing, evaluation and documentation of [(123)I]IBZM SPECT scans., Methods: The IBZM tool is an easy-to-use SPM toolbox. It includes automated procedures for realignment and summation of multiple frames (motion correction), stereotactic normalisation, scaling, VOI analysis of striatum-to-reference ratio R, classification of R and standardised display. In order to evaluate the tool, which was developed at the University of Hamburg, the tool was transferred to the University of Hannover. There it was applied to 27 well-documented subjects: eight patients with multi-system atrophy (MSA), 12 patients with Parkinson's disease (PD) and seven controls. The IBZM tool was compared with manual VOI analysis., Results: The sensitivity and specificity of the IBZM tool for the differentiation of the MSA subjects from the controls were 100% and 86%, respectively. The IBZM tool provided improved statistical power compared with manual VOI analysis., Conclusion: The IBZM tool is an expert system for the detection of reduced striatal D(2) availability on [(123)I]IBZM SPECT scans. The standardised documentation supports visual and semi-quantitative evaluation, and it is useful for presenting the findings to the referring physician. The IBZM tool has the potential for widespread use, since it appears to be fairly independent of the performance characteristics of the particular SPECT system used. The tool is available free of charge.

Objective: Fluorodeoxyglucose (FDG) positron emission tomography (PET) is increasingly used to support a diagnosis of Alzheimer's disease. The aim of the present study was to evaluate a new expert system (PALZ) for the fully automated analysis of FDG PET images for diagnosis of the disease., Methods: The PALZ tool is based on the detection of the typical disease pattern in FDG PET images. Its potential for this task was evaluated in 22 consecutive patients with suspected Alzheimer's disease who had been graded as positive for the pattern by an experienced reader (visual analysis supported by statistical parametric mapping (SPM)), and in 18 controls. Dependence on scanner performance was assessed by variation of the spatial resolution of the PET images., Results: All the Alzheimer's disease subjects were classified as pattern-positive by the PALZ tool. Fifteen controls were classified as normal. Sensitivity and specificity for differentiation of the patients with suspected Alzheimer's disease from the controls were 100% and 83%, respectively. The false positive finding in three controls most likely was caused by differences in attenuation correction between the normal data base of the PALZ tool (cold transmission scan) and the local data sets (hot transmission scan). There was only mild dependence on spatial resolution., Conclusions: The results of the present study suggest that the PALZ tool provides similar performance for the detection of the typical Alzheimer's disease pattern in FDG PET images as an experienced reader supported by SPM. The PALZ tool is fully automated, easy to use, and insensitive to the spatial resolution of the PET scanner used. Therefore, it has the potential for widespread clinical use.