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Background and purpose The aim of this study was to investigate whether morphological evidence of intracranial vascular injury can be found in the occluding thrombi of patients with ischemic stroke. Methods From 2015 until 2018 specimens of thrombi from patients with large vessel occlusion treated either by stent-assisted aspiration thrombectomy (TE) or by aspiration thrombectomy were prospectively collected. Thrombus specimens were formalin-fixed, paraffin-embedded and stained. Architectural features, presence of parts of vessel wall or atheromatous material, organisation of the thrombi, technique and number of thrombectomy manoeuvers were evaluated. Results Thrombus specimens from 302 patients were analyzed. 238 (80%) patients were treated with stent-assisted aspiration TE and 64 (20%) patients with aspiration TE only. 286 (95%) had fresh thrombi, 14 (4.6%) showed initial/complete thrombus organisation and multi-staged thrombi were found in 2 (Conclusions The overall risk of arterial vessel wall injury aspiration thrombectomy was low in our study. Aspiration thrombectomy and the procedure related with a retrieving device together with an ischemia time longer than 6 hours may increase the risk of vessel injury through the thrombectomy procedure. Further investigations are necessary to elucidate the influence of the mentioned aspects.

Purpose To investigate the role of the diffusion weighted imaging (DWI) in the acute dissection of internal carotid artery (ICA) and vertebral artery (VA) and assessing the length of intramural hematoma (IMH), caused by dissection. Methods We analyzed 28 patients presenting with a dissection of the ICA and/or VA with respect to the presence of high signal intensity areas on DWI suggestive of dissection and 20 control subjects without arterial dissection, some with and some without atherosclerotic lesions. ICA or VA dissection was defined by clinical and imaging, computed tomography angiography (CTA), MR angiography (MRA), and digital subtraction angiography (DSA) findings. The length of DWI hyperintensity was compared to length of the occlusion or stenosis on the angiographic examination. Results In 28 patients, 30 dissected arteries were analyzed. Time intervals from the onset of the first clinical symptoms to the radiological evaluation ranged from 1.5 h to 42 days. In 28 (93%) of the dissections, a high signal intensity of the affected artery was present on DWI. The measurement of the dissection length on DWI compared to DSA showed a mean deviation of 2.7 mm and a standard deviation of 3.7 mm. Conclusion DWI is a highly sensitive and valuable pulse sequence for the detection of dissected cervical arteries even in the first hours after symptom onset. In contrast to CTA and MRA, DWI can be a potential tool for a reliable measurement of the dissection length.

The brain imaging findings in children with neurological complications associated with influenza A infections are presented and analyzed and pathological imaging changes including atypical intracerebral hemorrhages in these patients are discussed. Neuroimaging findings in six children with influenza encephalopathy following influenza A infection between 2012–2017 were retrospectively investigated. Of these five underwent magnetic resonance imaging (MRI) and one computed tomography (CT). Gene analysis was performed in two cases with acute necrotizing encephalitis of childhood (ANEC). The MRI findings of one child were concordant with mild encephalopathy with a reversible splenial lesion (MERS); this patient recovered but remained aphasic. In two cases MRI showed typical bilateral thalamic lesions as a feature of ANEC; genetic testing facilitated the diagnosis in one case. One of the patients died, the other showed little improvement. The remaining three patients had multiple diffuse cerebral hemorrhages predominantly affecting the supratentorial white matter after influenza A infection complicated by pneumonia, rhabdomyolysis and sepsis requiring extracorporeal membrane oxygenation (ECMO). Neurological complications in children associated with influenza A infection may include MERS and ANEC. Additionally, atypical disseminated intracerebral hemorrhages as a complication of influenza A infection is reported.

Chronic mucocutaneous candidiasis, characterized by persistent or recurrent fungal infections, represents the clinical hallmark in gain-of-function (GOF) signal transducer and activator of transcription 1 (STAT1) mutation carriers. Several cases of intracranial aneurysms have been reported in patients with GOF STAT1 mutation but the paucity of reported cases likely suggested this association still as serendipity. In order to endorse this association, we link the development of intracranial aneurysms with STAT1 GOF mutation by presenting the two different cases of a patient and her mother, and demonstrate upregulated phosphorylated STAT4 and IL-12 receptor β1 upon stimulation in patient's blood cells. We also detected increased transforming growth factor (TGF)-β type 2 receptor expression, particularly in CD14+ cells, and a slightly higher phosphorylation rate of SMAD3. In addition, the mother of the patient developed disseminated bacille Calmette-Guerin disease after vaccination, speculating that GOF STAT1 mutations may confer a predisposition to weakly virulent mycobacteria.

Chronic granulomatous disease (CGD) is a rare genetic immunodeficiency which is characterized by recurrent severe bacterial and fungal infections caused by a defect in phagocytic cells due to loss of superoxide production. The disease usually manifests within the first years of life. Early diagnosis allows therapeutic intervention to improve the limited life expectancy. Nevertheless, only half of the patients exceed the age of 25. Here, we present the case of a 41-year old female patient who presented with an extensive spinal cord infection and atypical pneumonia mimicking tuberculosis. The medical history with recurrent granulomatous infections and microbiological findings with multiple unusual opportunistic pathogens was the key to the diagnosis of chronic granulomatous disease which is exceptionally rare first diagnosed in patients in the fifth decade of life. The late diagnosis in this case was likely to the lack of knowledge of the disease by the treating teams before but not because the patient did not have typical CDG infections along her life. The extensive progressive developing granulomas in our patient with fatal outcome raise the question of early immunosuppressive therapy in addition to anti-infectious treatment. We recommend appropriate CGD diagnostics in adult patients with unclear granulomatous diseases of the nervous system.

Congenital ornithine transcarbamylase deficiency (OTCD, OMIM 311250, Xp21.1) in humans results in hyperammonaemia with subsequent neurological symptoms including hypotonia, seizures and mental retardation. At the age of 3 years a hyperkinetic-hyperactive behaviour disorder of unknown origin was diagnosed in our female patient. The girl, ultimately diagnosed as having OTCD presented at the age of 6 years with an episode of feverassociated metabolic stroke including coma, epilepsy and further neurological symptoms due to hyperammonaemia. The pattern of plasma amino acids, the elevated level of orotic acid in urine and mutation analysis confirmed the diagnosis of OTCD. The possibility of early diagnosis and therapy of a disease which otherwise leads to severe neurological and psychiatric sequelae emphasizes the importance of precise evaluation of a possible organic cause for hyperkinetic-hyperactive behaviour disorders. This case of late-onset OTCD demonstrates that total recovery is possible even after a long comaepisode with slow reconvalescence. (J Pediatr Neurol 2004; 2(2): 97-100).

CSF abnormalities have been reported in CSF leakage syndrome. However, the mechanism for these CSF changes is actually unknown and they may indicate impaired CSF flow or blood-CSF barrier. Angiopoietin-2 (Ang-2), a protein which is expressed and released by endothelial cells, has been associated with increased vascular permeability. In the assumption that CSF changes are due to an impaired blood-CSF barrier, we hypothesized that subjects with persistent CSF leakage may have increased CSF Ang-2 levels. We enrolled 10 subjects with a clinically definite diagnosis of persisting CSF leakage syndrome and 10 control subjects. In CSF analyses, CSF to serum albumin ratio (Qalb) was the most frequently increased parameter indicating a disturbed blood-CSF barrier function. Comparison of the mean CSF Ang-2 levels, CSF to serum Ang-2 ratio (QAng-2), and QAng-2/Qalb between the control and CSF leakage patients did not show any significant difference. We suggest that the increase of Qalb results from a low CSF flow. Future studies with phase contrast-MRI in conjunction with CSF analyses before and after epidural blood patch treatment are required to address this question. It would be of particular interest whether Qalb can be used as a marker for successful nontargeted epidural blood patch treatment.

Severe neurological symptoms in Shiga toxin-producing Escherichia coli infection associated hemolytic–uremic syndrome (STEC–HUS) are often accompanied by none or only mild alterations of cerebral magnetic resonance imaging (MRI). This study aims to analyze if quantitative MRI is able to reveal cerebral pathological alterations invisible for conventional MRI. In nine patients with STEC–HUS associated severe neurological symptoms but inconspicuous cerebral MRI findings maps of the parameters T2 relaxation time, relative proton density (PD), apparent diffusion coefficient (ADC), and fractional anisotropy (FA) were generated. Quantitative values of these parameters were measured at the basal ganglia, thalamus, and white matter of the frontal and parietal lobe and compared to those of nine age- and sex-matched controls. Significant T2 prolongation (p

Diffusion-weighted imaging (DWI) in children with diarrhoea associated haemolytic uraemic syndrome (D+HUS) and cerebral involvement was evaluated retrospectively.DWI within 24 h of onset of neurological symptoms. The apparent diffusion coefficient (ADC) was measured in grey/white matter and correlated with clinical and laboratory findings.DWI was abnormal in all. Abnormal ADC was detected in the supratentorial white matter (6/12) and cortex (1/12), the basal ganglia (5/12), the thalami (4/12), and the cerebellum (1/12). ADC was reduced in 5/12, increased in 4/12, and both in 3/12. Mean serum sodium was lower in patients with DWI abnormalities affecting the white matter (6/12), than in those with basal ganglia/thalamic involvement (6/12). Neurological outcome was normal in 4/11 and abnormal in 7/11, and 1 patient died, outcome did not correlate to either localisation or type of DWI abnormality.In D+HUS with neurological symptoms, early DWI may reveal abnormal ADC not only in the basal ganglia/thalami, but also in the white matter/cortex. Besides thrombotic microangiopathy, toxic effects of shiga toxin, azotaemia and hyponatraemia / hypoosmolality may be involved in cerebral involvement in children with D+HUS. Findings on early MRI seem not to predict clinical course or outcome.• DWI MR imaging may detect early CNS involvement in haemolytic uraemic syndrome • Different pathogenetical mechanisms may contribute to the CNS disease in HUS • Early MRI findings do not seem to allow prediction of clinical outcome.

SummaryWe report the case of a 50-year-old female patient with non-active sarcoidosis and no kind of immunosuppression, admitted to our hospital because of increasing confusion and focal neurological deficits. Initially a tumor, herpes encephalitis, or neurosarcoidosis were suspected, but surprisingly biopsy revealed progressive multifocal leukoencephalopathy, additionally confirmed by JC-positive PCR in cerebrospinal fluid. Cases of sarcoidosis and progressive multifocal leukoencephalopathy have been reported before. This is the first case of a patient with no sign of active sarcoidosis and without immunosuppressive therapy who recovered spontaneously with a follow-up time of nearly 3 years.

We describe a distributed parameter (DP) model for tracer kinetic analysis in brain and validate the derived perfusion values with positron emission tomography (PET) scans. The proposed model is applied on actual clinical cases of hemispheric stroke. Nine patients with experienced transient ischaemic attack or minor stroke and a stenosis of the internal carotid artery were referred for computed tomography (CT) and PET imaging. The applicability of the DP model in clinical practice was tested in seven patients with acute stroke who received a baseline perfusion CT study and a noncontrast follow-up CT study after 2.461.8 days. The mean blood flow (F) value for all patients with carotid stenosis in the pooled data (54 regions of interest (ROIs)) was 37.9611.2 mL/min per 100 g in perfusion CT and 35.669.8 mL/min per 100 g in perfusion PET imaging [r = 0.77 (P = 0.00)]. Regression analysis of the pooled ROIs for every patient revealed significant correlation between F values in seven patients [r = 0.50 to 0.79 (r 2 -values ranged from 0.45 to 0.79), (0.01 < P < 0.05)]. Parametric maps that corresponded to all physiologic parameters were generated for every perfusion CT in the patients with acute stroke using the DP model. The ischaemic area was better delineated in F, intravascular blood volume and lag time (tlag) maps. The correlation coefficient comparing the visually outlined regions of abnormality between the tlag parametric map and the follow-up CT scans was 0.81 (P = 0.003). In conclusion, DP physiological model using more realistic pharmacokinetics is feasible in dynamic contrast-enhanced CT of the brain in patients with acute and chronic cerebrovascular disease. Journal of Cerebral Blood Flow & Metabolism (2008) 28, 402–411; doi:10.1038/sj.jcbfm.9600522; published online 27 June 2007

Alexander disease is a rare disorder of cerebral white matter due to a dysfunction of astrocytes. The most common infantile form presents as a megalencephalic leukodystrophy. Mutations of the GFAP gene, encoding Glial Fibrillary Acidic Protein, have been recognized as the cause of Alexander disease. Glial Fibrillary Acidic Protein is the major intermediate filament protein in astrocytes, its functional rod domain is conserved in sequence and structure among other intermediate filament proteins. We report here two cases of infantile Alexander disease with early onset and severe course, caused by DE NOVO mutations A364 V and Y366C. Both affected GFAP residues are part of a highly conserved coiled-coil trigger motif in the C-terminal end of segment 2B, probably required for the stability of intermediate filament molecules. Comparable effects are seen with mutations of the corresponding residues of the gene coding for keratin 14, another intermediate filament, this further supports the hypothesis that these positions of the trigger motif are generally critical for a normal function of intermediate filaments.

Schimke-immuno-osseous dysplasia is an autosomal-recessive multisystem disorder with the prominent clinical features disproportionate growth failure, progressive renal failure, and T-cell immunodeficiency. Neurological symptoms caused by transient ischemic attacks (TIAs) and strokes are a typical clinical finding in severe SIOD. Cerebral ischemia and white matter changes, moyamoya phenomena and absence of a cerebellar hemisphere and partial absence of the cerebellar vermis have been described in patients with severe SIOD. We present three SIOD patients with atrophy of the caudal parts of the cerebellar vermis (posterior lobule) and of the cerebellar hemispheres. We hypothesize that these cerebellar abnormalities are a continuum of the ongoing vascular disease in severe SIOD.

Background and Purpose— Preclinical studies have revealed that the endogenous nitric oxide synthase inhibitor, asymmetric dimethylarginine (ADMA), increases vascular tone in cerebral blood vessels. Marked elevations of ADMA blood levels were found in patients with diseases characterized by decreased cerebral perfusion, such as ischemic stroke. Arterial stiffness is an independent predictor of stroke and other adverse cardiovascular events. The aim of this study was to investigate the influence of a systemic subpressor dose of ADMA on arterial stiffness and cerebral perfusion in humans. Methods— Using a double-blind, vehicle-controlled study design, we allocated 20 healthy men in random order to infusion of either ADMA (0.10 mg ADMA/kg per min) or vehicle over a period of 40 minutes. Arterial stiffness was assessed noninvasively by pulse wave analysis. All volunteers underwent measurement of cerebral perfusion by dynamic contrast-enhanced perfusion magnetic resonance imaging of the brain. Results— Infusion of ADMA significantly decreased total cerebral perfusion by 15.1±4.5% ( P =0.007), whereas blood flow in the vehicle group increased by 7.7±2.8% ( P =0.02). ADMA also increased arterial stiffness as assessed by measurement of the augmentation index (−12.6±1.9 to −9.6±1.5, P =0.007). Conclusions— Our results document for the first time that subpressor doses of ADMA increase vascular stiffness and decrease cerebral perfusion in healthy subjects. Thus, ADMA is an important endogenous modulator of cerebral vascular tone and may be involved in the pathogenesis of cerebrovascular disease.

Twelve patients with ICA stenosis underwent dynamic perfusion computed tomography (CT) and positron emission tomography (PET) studies at rest and after acetazolamide challenge. Cerebral blood flow (CBF) maps on perfusion CT resulted from a deconvolution of parenchymal time-concentration curves by an arterial input function (AIF) in the anterior cerebral artery as well as in both anterior choroidal arteries. CBF was measured by [(15)O]H(2)O PET using multilinear least-squares minimization procedure based on the one-compartment model. In corresponding transaxial PET scans, CBF values were extracted using standardized ROIs. The baseline perfusion CT-CBF values were lower in perfusion CT than in PET (P0.05). CBF values obtained by perfusion CT were significantly correlated with those measured by PET before (P0.05) and after (P0.01) acetazolamide challenge. Nevertheless, the cerebrovascular reserve capacity was overestimated (P=0.05) using perfusion CT measurements. The AIF selection relative to the side of carotid stenosis did not significantly affect calculated perfusion CT-CBF values. In conclusion, the perfusion CT-CBF measurements correlate significantly with the PET-CBF measurements in chronic carotid stenotic disease and contribute useful information to the evaluation of the altered cerebral hemodynamics.

Background and Purpose— Knowledge about cytotoxic edema (CE) in intracerebral hemorrhage is still limited. We aimed to analyze its presence, temporal pattern, and prognostic meaning. Methods— Twenty-one patients with primary intracerebral hemorrhage underwent magnetic resonance imaging at days 1, 3, and 7 after symptom onset. CE was identified using diffusion-weighted imaging. Hematoma and perihematomal edema volumes were measured on fluid-attenuated inversion recovery images. National Institutes of Health Stroke Scale score was assessed at admission and with each magnetic resonance imaging. Clinical outcome was assessed by modified Rankin scale at 90 days. Results— CE appeared in half of the patients within the first 24 hours. The apparent diffusion coefficient values decreased until day 3 and were significantly reversed from days 3 through 7 ( P P =0.036) than those without. Larger 3-day perihematomal edema volume ( P =0.02) and presence of CE on day 3 ( P =0.07) were associated with poor clinical outcome. Conclusions— CE is associated with stroke severity, perihematomal edema volume, and poor outcome. It is considered to indicate ongoing neuronal injury and, thus, might emerge as new treatment target.

Background The cannabinoid CB 1 receptor agonist Δ 9 -THC has been suggested for treatment of Tourette syndrome (TS). Based on animal studies, the CB 1 antagonist [ 123 I]AM281 (N-(Morpholin-4-yl)-1-(2,4-dichlorophenyl)-5-(4-[ 123 I]iodophenyl)-4-methyl-1H-pyrazole-3-carboxamide) has been proposed for single photon emission computed tomography (SPECT) in humans. Our aims were to 1) evaluate specific binding of [ 123 I]AM281 to CB 1 receptors in TS patients and 2) assess radiation exposure associated with the use of AM281 labeled with 123 I for SPECT and 124 I for positron emission tomography. Methods We employed [ 123 I]AM281 in six TS patients before and after Δ 9 -THC treatment. Dynamic SPECT, plasma measurements (including metabolite analysis with thin layer chromatography), and whole-body imaging were performed. Regions of interest derived from magnetic resonance images were used to extract from SPECT uptake in an area with high CB 1 density (lentiform nuclei) and reference regions. Specific over nonspecific partition coefficients V 3 ′′ were calculated. Whole-body images were carried out for dosimetric analysis. Data obtained with [ 123 I]AM281 were used to predict doses from [ 124 I]AM281. Results Mean V 3 ′′ ranged from .19 to .31 and did not change significantly after Δ 9 -THC treatment. Nevertheless, in the only patient with a marked clinical response, V 3 ′′ clearly declined. Thin layer chromatography revealed biexponential kinetics of tracer metabolism; about 60% remained nonmetabolized after 3 hours. Effective doses of .011 mSv/MBq for [ 123 I]AM281 and .34 for [ 124 I]AM281 were computed. Conclusions This study suggests that specific binding of [ 123 I]AM281 to CB 1 receptors can be detected in patients using SPECT. Radiation exposure with [ 123 I]AM281 is low; that with [ 124 I]AM281 is higher but acceptable for single investigations.

Fusion of medical images is a technique that permits the correlation of homologous anatomical structures in different imaging modalities on the basis of a spatial transformation of the data sets. CT and MRI of the spine provide complementary information of possible relevance for diagnostic and therapeutic decisions. Methods enabling a multisegmental CT-MRI fusion of the spine were developed. These solve the problem of altered spatial relationships of the individual anatomical structures due to differing patient positioning in successive data acquisitions. Routine clinical CT and MRI data of a thoracic section of the spine were obtained and transferred to a PC-workstation. Following segmentation of the CT-data, landmarks for each individual vertebra were defined in the CT and MRI data. For each individual vertebra the algorithm we developed then carried out a rigid registration of the CT information to the MR data. The fused data sets were presented as colour-coded images or on the basis of dynamic variation of transparency. To assess registration precision, fiducial registration errors (FRE) and target registration errors (TRE) were calculated. The algorithm permitted multi-segmental image fusion of the spine. The average time required for defining the landmarks was 22 seconds per landmark for CT, and 34 seconds per landmark for MR. The average FRE was 1.53 mm. The TRE for the vertebrae was less than 2 mm. The colour-coded images were particularly suitable for assessing the contours of the anatomical structures, whereas dynamic variation of the transparency of overlapping CT images enabled a better overall assessment of the spatial relationship of the anatomical structures. The algorithm permits precise multi-segmental fusion of CT and MR of the spine, which was not possible using current fusion-algorithms due to variations in the spatial orientation of the anatomical structures caused by different positioning of the axial skeleton in successive examinations.

Digital images generated by medical imaging form the basis for radiological diagnosis and surgical planning. Despite the advent of the DICOM 3.0 standard for medical image communication, widespread application of the existing information is often limited by incompatibility of the data formatting used by different equipment generations, and the manufacturer-specific standards employed. An exchange interface based on magneto optical discs has been developed to retrieve and present medical image data regardless of the technological hardware and the specific formats used. Specially adapted routines to retrieve the data first had to be developed. A modular program structure was used to allow flexibility in the implementation of further routines and other exchange media. Over 20,000 CT and MRI images including header information obtained from different General Electric and Siemens scanners were extracted successfully from MO discs. The image data were used for follow up and surgical planning and were transferred to a PAC-server. The interface proved reliable and easy to use. Support for further proprietary formats is currently being developed. The present exchange interface permits reliable retrieval of digital images for diagnostic and surgical planning purposes, regardless of the hardware generation and manufacturer-specific formats.

The aim of the present study was to use four different methods to evaluate three radiographic techniques for their accuracy in assessing the marginal periimplant bone levels at implants with buccal bone defects in an experimental setting. Twenty-four implants were placed in the mandibles of six adult beagle dogs with substantial buccal bone defects, which were augmented by bone particles with and without resorbable membranes. After healing for 5 months, (1) periapical radiographs, (2, 3) reformatted images in (2) sagittal and (3) coronal planes from axial computer tomography (CT) scans and (4) direct magnification images (DIMA) were made and compared with histometric analysis of bone levels. Two values were used for comparison: (i) the lingual bone level and (ii) the true bone level calculated as a mean value from the lingual and the buccal bone levels of all histologic sections of each implant. Metric evaluation of periapical radiographs, sagittal reformation of CT scans and DIMA showed that the results were close to the histometrically assessed lingual bone level, while the true bone level was significantly lower and not reflected by any of the imaging modalities. Coronal reformation showed that there was significant overestimation of the lingual and underestimation of the buccal bone level when compared with histometric values. It is concluded that assessment of bone level and bone regeneration in implants with buccal bone defects remains problematic, and data from periapical radiograms tend considerably to overestimate the bone anchorage of these implants.

The aim of this study was to analyze the neurological involvement and outcome in pediatric patients with hemolytic uremic syndrome (HUS) during the 2011 epidemic caused by Escherichia coli O104:H4.Clinical data and data from magnetic resonance imaging (MRI) scans and electroencephalography (EEG) during the acute phase of the disease and during follow-up at 3 and 6 months were analyzed in 50 patients. Twenty-five of these patients underwent neuropsychological testing (WISC IV) during follow-up.Neurological involvement (stupor or coma, seizures, visual disturbances, paresis, myocloni) was initially observed in 14/50 (28%) patients. One patient died. EEG abnormalities were more frequent in patients with neurological involvement than in those without (12/14 vs. 13/25, respectively). Cranial MRI scans were analyzed in nine patients with neurological involvement, of whom five showed abnormal findings. At the 3- and 6-month follow-ups, EEG abnormalities were found in 14/40 (35%) and 7/36 (19%) patients, respectively, whereas 28/42 (67%) and 17/39 (44%) patients, respectively, complained about on-going reduced performance. Neuropsychological testing showed a slightly lower global intelligence quotient in patients with neurological involvement versus those without (113.4 ± 2.8 vs. 119.4 ± 1.8, respectively).Neurological involvement was frequent in our cohort. Accordingly, the incidence of pathological EEG findings was high, even in patients without clinical signs of neurological involvement. Nevertheless, major neurological sequelae were rare, and neuropsychological outcome was favorable after 6 months.

Smooth muscle tumours (SMT) after transplantation (PTSMT) or associated with congenital immunodeficiency syndromes (CI-SMT) and human immunodeficiency virus (HIV-SMT) are rare. The majority of PTSMT and CI-SMT are associated with Epstein-Barr virus (EBV), while some HIV-SMT can be EBV-negative. SMT in immunodeficient states may present with unspecific symptoms which are mainly related to tumour localisation. In PTSMT, >50% of tumours manifest in the liver/transplant liver, but in general PTSMT, HIV-SMT and CI-SMT can occur at any site as single or multiple tumours. Multiple tumour manifestations do not define metastatic disease as PTSMT can occur synchronously and/or metachronously. PTSMT can originate from the recipient as well as from the donor. Morphologically, most tumours, in particular PTSMT, lack marked histological atypia or tumour necrosis, while some HIV-SMT and CI-SMT can present as sarcoma-like variants, but histomorphology does not predict clinical aggressiveness or tumourbiological behaviour. In PTSMT, surgery and reduced immunosuppression show comparable overall survival rates, while poor prognosis is mainly associated with intracranial manifestation and non-resectable tumours. In HIV-SMT and CI-SMT, surgery should be performed. In all 3 tumour types, adverse prognosis is mainly related to comorbidities associated with immunosuppression but not with the extent of histological atypia or tumour size.

BACKGROUND: Patients undergoing hemodialysis treatment have a six-fold increased risk for stroke relative to the general population. However, the effect of hemodialysis on cerebral blood flow is poorly studied and confounding factors like blood pressure and ultrafiltration as well as temperature changes have rarely been accounted for. The aim of our study was to use state-of-the-art technology to evaluate the effect of a single dialysis session on cerebral perfusion as well as on vascular stiffness. METHODS: Chronic hemodialysis patients (7 male/3 female, mean age 58 years) were recruited. Cerebral blood flow and arterial pulse wave velocity were measured before and immediately after a hemodialysis session. To exclude effects of volume changes we kept ultrafiltration to a minimum, allowing no change in body weight. Isothermic conditions were maintained by using the GENIUS single-pass batch-dialysis system with a high-flux polysulfone dialyser. Cerebral blood flow was measured by contrast-enhanced computed tomography. Pulse wave velocity was measured using the SphygmoCor (AtCor Medical, USA) device by a single operator. RESULTS: This study shows for the first time that isovolemic, isothermic hemodialysis neither affected blood pressure or heart rate, nor total or regional cerebral perfusion. There was also no change in pulse wave velocity. CONCLUSIONS: Mechanisms other than the dialysis procedure itself might be causative for the high incidence of ischemic strokes in this patient population. Moreover, the sole removal of uremic toxins does not lead to short-term effects on vascular stiffness, underlying the importance of volume control in this patient population.

Objective: To describe the neurologic and neuroradiologic complications of Shiga toxin producing Escherichia coli infection (STEC)–associated hemolytic-uremic syndrome (HUS) in adults. Methods: All 52 adult patients with STEC O104:H4 infection cared for at Hannover Medical School during the outbreak in Germany through May–July 2011 are considered in this observational study. Forty-three of the 52 patients underwent a standard neurologic diagnostic procedure including clinical examination, Mini-Mental State Examination, and Glasgow Coma Scale Score. Thirty-six patients underwent EEG, and 26 had cerebral MRI, 9 of them repeatedly. Case records of 9 patients who had not been seen by a neurologist were analyzed retrospectively. Results: Forty-eight of the 52 patients had HUS. All but 1 of these showed neurologic symptoms. Focal neurologic signs like double vision, difficulties in finding words, or hyperreflexia were present in 23, additional deficits in orientation, attention, memory, or constructive abilities in 9, and marked impairment of consciousness in 15. MRI showed brainstem, midbrain, thalamus, corpus callosum, and white matter lesions in half of the patients, predominantly in diffusion-weighted images. The extent of MRI lesions did not correlate with clinical symptoms. General slowing but no focal alteration was found in half of the patients examined by EEG. Conclusion: Our findings suggest a toxic-metabolic pathology behind the neurologic impairment instead of multiple infarction due to microthrombosis. Future studies should aim to clarify if early antibiotic therapy or bowel cleansing might help to decrease the rate of neurologic complications in STEC-HUS.

Hurler-Scheie syndrome is caused by alpha-l-iduronidase deficiency. Enzyme replacement therapy (ERT) can improve physical capacity and reduces organomegaly. However, the effect on bradytrophic connective tissue is limited. As intravenously administered enzyme cannot cross the blood-brain barrier, the therapy of choice for the more severe Hurler syndrome is haematopoietic stem cell transplantation (HCT). In the more attenuated Scheie syndrome, neurological impairment is less severe; therefore, ERT may be appropriate to treat these patients. Information on long-term outcome in Scheie patients undergoing ERT is scarce. We report a 38-year-old female Scheie patient who has been on ERT for 8 years. While non-neurological symptoms improved, she developed paresthesias in her hands and feet and progressive pain in her legs. Somatosensory evoked potentials were abnormal, suggesting dysfunction of the dorsal funiculus and lemniscus medialis. After 6 years of ERT, a spinal MRI showed dural thickening at the upper cervical spine. These soft-tissue deposits are presumably due to the accumulation of mucopolysaccharides. Intramedullary hyperintensities at the level of C1/2 revealed cervical myelopathy. An MRI before the start of ERT had shown milder spinal lesions. Cystic lesions in the white matter of the centrum semiovale due to dilated Virchow-Robin spaces were essentially unchanged compared with the MRI scan before ERT. Decompression of the spinal cord resulted in clinical improvement. In an adult patient with Scheie syndrome, ERT failed to prevent progression of cervical myelopathy. Clinical significance of cerebral changes is unclear. Whether early HCT or intrathecal ERT could have prevented these lesions remains speculative.

Hurler syndrome (mucopolysaccharidosis type 1H; MPS1H) is a lysosomal storage disease caused by a deficiency of alpha-L-iduronidase activity. The natural course of this neurodegenerative disease inevitably leads to premature death within the first 10 years of life. Enzyme replacement therapy is effective in correcting the enzymatic deficiency of organs other than the central nervous system. Hematopoietic stem cell transplantation (SCT) is the only treatment known to prevent psychomotor deterioration. However, the classical transplantation protocols resulted in a high incidence of graft failure and regimen-related toxicity. Recently, we published a well-tolerated, fludarabine-based, radiation-free conditioning regimen for SCT in patients with Hurler syndrome. Here we report the developmental outcome (assessed by the Denver Developmental Screening Test before and yearly after SCT) of four females and one male with MPS1H (mean age at last follow-up 71mo, range 42-87mo) treated in accordance with this strategy. Mean age at SCT was 25 months (range 10-36mo). All children were engrafted and in ambulatory care. They all showed psychomotor development without neurodegeneration. In all patients, after SCT a regression of intracranial lesions could be seen that paralleled the psychomotor improvements. SCT led to a relative reduction of head circumference in all cases.

Objectives: We sought to evaluate the accuracy of the perfusion computed tomography (PCT) deconvolution-based brain perfusion measurements and the lesions' (infarct and penumbra) volumetric with regard to arterial input function (AIF) selection in patients with acute stroke. Materials and Methods: Eighteen consecutive patients with symptoms of acute stroke underwent PCT at admission. Follow-up magnetic resonance imaging was obtained in all patients after 3.6 ± 1.7 days (range, 1.5-6 days). PCT maps were generated focusing on the anterior cerebral artery (ACA) and branches of the middle cerebral artery (MCA) ipsilateral and contralateral to the ischemic lesion as AlFs. Infarct, penumbra, and total ischemic lesion were delineated on cerebral blood flow (CBF) maps. CBF, cerebral blood volume (CBV), and mean transit time (MTT) were calculated in the ischemic regions as provided by the 3 different AlFs, the normality test was applied for the obtained parameters, and the values were correlated (Pearson's correlation coefficient). Volumes of the ischemic regions (as obtained by the different AIFs) also were correlated and compared (paired τ test) to the follow-up infarct volume. Results: The CBF and CBV values obtained by the different AlFs in the infarct, penumbra, and total ischemic lesion were significantly correlated (r = 0.94-0.96, P ≤ 0.01). Only in the infarct region calculated MTT values were correlated (r = 0.88-0.91, P < 0.05) between the different AlFs groups. High correlation coefficients (r = 0.79-0.91, P < 0.001) were observed between the admission PCT infarct and total ischemic volume and the MRI follow-up infarct volume. ACA as AIF provided the best correlations (r = 0.91, P = 0.0002) with the follow-up measurements. No statistically significant difference was found between the 3 different AlF-estimated admission total ischemic volumes and the follow-up infarct volume. Conclusions: The AIF selection in the ACA as well as in the ipsilateral (to the hypoperfused area) or contralateral branches of the MCA has no statistically significant impact on the calculation of the CBF, CBV values, and the volume estimation of the ischemic region in the acute stroke patients.

We studied central cannabinoid CB 1 receptors in a schizophrenic patient using the pyrazole derivative AM281 labelled with the positron-emitting nuclide iodine-124. A dynamic positron emission tomography (PET) acquisition with simultaneous blood sampling was performed up to 1.5 h post-injection. The classical Logan plot analysis was applied to generate a three-dimensional map of distribution volume (DV). The map was spatially normalised into the Montreal Neurological Institute stereotactic space. Using a volume of interest (VOI) template, mean values of DV were extracted from multiple grey matter regions and white matter (as a reference). As a measure of regional receptor availability, ratios of DV in grey matter to DV in white matter minus one (DVR−1) were calculated. The highest receptor binding was observed in the striatum and the pallidum (DVR−1: 0.35–0.37). Binding in basal ganglia regions was lower on the left than the right side. Moderately high binding was seen in the frontal cortex (0.22), the temporal cortex (0.18) and the cerebellum (0.15). In conclusion, 124 I-AM281 PET can be used to reveal areas with prominent CB 1 receptor binding. Nevertheless, limited image contrast and relatively high radiation exposure (physical half-life of 124 I: 4 days) have to be taken into account. Asymmetric receptor binding may possibly reflect pathologic changes in schizophrenia.

New information technologies offer the possibility of major improvements in the professional education and advanced training of physicians. The web-based, multimedia teaching and learning application Schoolbook has been created and utilized for neuroradiology. Schoolbook is technically based as a content management system and is realized in a LAMP environment. The content is generated with the help of the developed system and stored in a database. The layout is defined by a PHP application, and the webpages are generated from the system. Schoolbook is realized as an authoring tool so that it can be integrated into daily practice. This enables the teacher to autonomously process the content into the web-based application which is used for lectures, seminars and self-study. A multimedia case library is the central building block of Schoolbook for neuroradiology, whereby the learner is provided with original diagnostic and therapeutic data from numerous individual cases. The user can put individual emphasis on key learning points as there are various ways to work with the case histories. Besides the case-based way of teaching and learning, a systematically structured way of dealing with the content is available. eLearning offers various opportunities for teaching and learning in academic and scientific as well as in economic contexts. Web-based applications such as Schoolbook may be beneficial not only for basic university education but also for the realization of international educational programmes such as the European Master of Medical Science with a major in neuroradiology.

Objective: In this study, perfusion CT and diffusion-weighted magnetic resonance imaging (DWI) were compared as means of assessing the ischemic brain in hyperacute stroke. Methods: Twenty patients with ischemic stroke underwent perfusion computed tomography (CT) and magnetic resonance imaging (MRI) studies

The aim of the present study was to use four different methods to evaluate three radiographic techniques for their accuracy in assessing the marginal periimplant bone levels at implants with buccal bone defects in an experimental setting. Twenty-four implants were placed in the mandibles of six adult beagle dogs with substantial buccal bone defects, which were augmented by bone particles with and without resorbable membranes. After healing for 5 months, (1) periapical radiographs, (2, 3) reformatted images in (2) sagittal and (3) coronal planes from axial computer tomography (CT) scans and (4) direct magnification images (DIMA) were made and compared with histometric analysis of bone levels. Two values were used for comparison: (i) the lingual bone level and (ii) the true bone level calculated as a mean value from the lingual and the buccal bone levels of all histologic sections of each implant. Metric evaluation of periapical radiographs, sagittal reformation of CT scans and DIMA showed that the results were close to the histometrically assessed lingual bone level, while the true bone level was significantly lower and not reflected by any of the imaging modalities. Coronal reformation showed that there was significant overestimation of the lingual and underestimation of the buccal bone level when compared with histometric values. It is concluded that assessment of bone level and bone regeneration in implants with buccal bone defects remains problematic, and data from periapical radiograms tend considerably to overestimate the bone anchorage of these implants.