Myoinositol as a Biomarker in Recurrent Glioblastoma Treated with Bevacizumab: A 1H-Magnetic Resonance Spectroscopy Study.

BACKGROUND: Antiangiogenic treatment of glioblastomas with Bevacizumab lacks predictive markers. Myoinositol (MI) is an organic osmolyte, with intracellular concentration changes depending on the extracellular osmolality. Since Bevacizumab markedly reduces tumor edema and influences the tumor microenvironment, we investigated whether the MI concentration in the tumor changes during therapy. METHODS: We used 1H-magnetic resonance spectroscopy to measure the MI concentrations in the tumor and contralateral control tissue of 39 prospectively recruited patients with recurrent glioblastomas before and 8-12 weeks after starting therapy. 30 patients received Bevacizumab and 9 patients were treated with CCNU/VM26 as control. We performed a survival analysis to evaluate MI as a predictive biomarker for Bevacizumab therapy. RESULTS: MI concentrations increased significantly during Bevacizumab therapy in tumor (p < .001) and control tissue (p = .001), but not during CCNU/VM26 treatment. For the Bevacizumab cohort, higher MI concentrations in the control tissue at baseline (p = .021) and higher differences between control and tumor tissue (delta MI, p = .011) were associated with longer survival. A Kaplan-Meier analysis showed a median OS of 164 days for patients with a deltaMI < 1,817 mmol/l and 275 days for patients with a deltaMI > 1,817 mmol/l. No differences were observed for the relative changes or the post treatment concentrations. Additionally calculated creatine concentrations showed no differences in between subgroups or between pre and post treatment measurements. CONCLUSION: Our data suggest that recurrent glioblastoma shows a strong metabolic reaction to Bevacizumab. Further, our results support the hypothesis that MI might be a marker for early tumor cell invasion. Pre-therapeutic MI concentrations are predictive of overall survival in patients with recurrent glioblastoma treated with Bevacizumab.

Spectroscopic Characterization of Gliosarcomas-Do They Differ From Glioblastomas and Metastases?

OBJECTIVE: To evaluate the spectroscopic pattern of gliosarcomas for differentiation from glioblastomas or metastases. METHODS: H-nuclear magnetic resonance (NMR) spectroscopic intermediate echo time data of 5 patients with histologically proven gliosarcomas were compared with data of 17 metastases and 54 glioblastomas. Specialized H-NMR spectroscopy analysis software was used offline. Lipid and macromolecular resonances between 0.9 ppm and 1.4 ppm were compared besides the main metabolites using the Mann-Whitney U test. RESULTS: Gliosarcomas showed higher lipid and macromolecule resonances and a higher lipid-choline ratio compared with glioblastomas (P < 0.024 and P < 0.036). Glioblastomas showed higher creatine concentrations compared with metastases (P < 0.007) but not compared with gliosarcomas. We found no significant differences between metastases and gliosarcomas. CONCLUSIONS: Gliosarcomas may mimic metastases on H NMR spectroscopy showing high signal intensities from lipid and macromolecule resonances. This tumor type should be suspected if conventional imaging suggests an intra-axial brain neoplasm in combination with high lipids in solid tumor parts.

T2'- and PASL-based perfusion mapping at 3 Tesla: influence of oxygen-ventilation on cerebral autoregulation.

PURPOSE: To use T2'-mapping together with Pulsed Arterial Spin Labeling (PASL) providing quantitative information of deoxygenation level and cerebral blood flow (CBF) in the cerebral gray matter to obtain simultaneous information about the cerebral oxygen metabolism and the resulting cerebral vasoreactivity under normoxic and hyperoxic conditions. MATERIALS AND METHODS: Twelve young, healthy volunteers underwent MRI under normoxic and hyperoxic conditions performing PASL and high-resolution, motion-corrected T2* and T2-mapping to calculate T2'values. Regions of interest (ROI) were placed in the frontoparietal cortex and thalamus by manual and automatic segmentation. For each ROI, mean normoxic T2'- and CBF values were extracted and compared with the same parameters assessed under hyperoxic ventilation. RESULTS: A hyperoxic-induced decrease of the CBF could be shown in the frontoparietal cortex (P = 0.009). The T2 values of frontoparietal cortex decreased under hyperoxic inhalation compared with normoxia (P = 0.01), whereas T2' remained unchanged. CONCLUSION: Motion-corrected high-resolution T2'-maps can be used together with PASL to evaluate the DeoxyHb content in relation to CBF in the cerebral gray matter. We could show that cortical CBF decreases under hyperoxic inhalation in healthy young subjects, whereas the T2' values remained constant. These data suggest that hyperoxic-induced vasoconstriction may protect the brain against hyperoxemia.

Morphometry and diffusion MR imaging years after childhood traumatic brain injury.

OBJECTIVE: Our goal was to detect possible unrecognized injury in cerebral white matter (WM) in adult survivors of traumatic brain injury (TBI) during childhood, who showed no detectable axonal injury or chronic contusion on late conventional MRI. MATERIAL AND METHODS: We used voxel-based morphometry (VBM) to detect subtle structural changes in brain morphology and diffusion-tensor imaging (DTI) to non-invasively probe WM integrity. By means of VBM and DTI we examined a group of 12 adult patients who suffered from childhood closed head injury without axonal injury on late conventional MRI. RESULTS: Patients sustained complicated mild or moderate-to-severe TBI with a mean of 7 points based on the Glasgow Coma Scale. The mean time after trauma was 19 years (range 7-31 years). For VBM, group comparisons of segmented T1-weighted grey matter and WM images were performed, while for DTI we compared the fractional anisotropy and mean diffusivity (MD) between the groups. Patients presented with higher MD in the right cerebral white matter, bilaterally in the forceps major and in the body and splenium of the corpus callosum. These findings were supported by VBM, which showed reduced WM volume bilaterally, mainly along the callosal splenium. CONCLUSION: Our results indicate that persistent focal long-term volume reduction and underlying WM structural changes may occur after TBI during childhood and that their effects extend into adulthood. Normal late conventional MR findings after childhood TBI do not rule out non-apparent axonal injury.

MR spectroscopy differentiation between high and low grade astrocytomas: a comparison between paediatric and adult tumours.

OBJECTIVE: To investigate whether pathologically similar astrocytomas in adults and children may also show metabolic similarities in proton magnetic resonance spectroscopy ((1)H-MRS) and whether the MRS data could help to differentiate between low and high grade gliomas for the different groups. MATERIAL AND METHODS: Twelve children (5 WHO II astrocytomas, 7 WHO III astrocytomas) and 37 adults (21 WHO II astrocytomas, 16 WHO III astrocytomas) were included in this study. MR spectroscopic data were evaluated retrospectively using normalized measures of total choline (tCho), N-acetyl-aspartate (NAA) and total creatine (tCr). These metabolites were used to differentiate between WHO II and WHO III astrocytomas in children and adults. Histopathological grading was performed using WHO criteria. (1)H-MRS was carried out prior to the commencement of any treatment. Signal intensities of tCho, NAA and tCr were normalized to their values in contralateral brain tissue. The resulting concentration ratios were then used to calculate the change in the intratumoural ratio of NAA to tCho. A Mann-Whitney U-Test was performed to evaluate differences within the respective groups. RESULTS: In both groups, loss of NAA and increase of tCho were more pronounced in WHO III than in WHO II astrocytoma. The best discriminator to differentiate between low and high grade gliomas was found to be the ratio of NAA/tCho (p < 0.01). CONCLUSION: The normalized metabolite signal intensities ratio NAA to tCho is the most accurate in differentiating between low and high grade astrocytomas in both children and adults.

Stripe-like increase of rCBV beyond the visible border of glioblastomas: site of tumor infiltration growing after neurosurgery.

We observed a stripe-like pattern of regional cerebral blood volume (rCBV) increase in a defined region adjacent to the contrast enhancement (CE) on MRI of glioblastomas (GBM) that we defined as the "striate sign" (SS). We hypothesized that the SS marks infiltration of GBM outside the CE volume transforming into future CE tumor in the follow-up. T2*-weighted dynamic susceptibility-weighted CE (DSC)-MRI, and T1 and T2-weighted images (WI) of 16 patients with GBM were retrospectively evaluated in a baseline MRI performed before neurosurgery. In seven of these patients we also performed a (1)H MR spectroscopic imaging ((1)H MRSI). The regions of interest (ROI) delineating the SS were defined on rCBV maps for each patient. ROIs were overlaid on follow-up T1-WI and T2-WI MRI performed 3, 6, and 9 months after neurosurgery. Size and maximum signal intensity (max SI) of de novo CE within the area of the SS were analyzed. Statistical analysis was performed with the Friedman test (P < 0.05). In 15/16 patients de novo CE completely covered the area of the SS within nine months. Normalized max SI of de-novo CE of the 3, 6, and 9-months follow-up MR examinations were significantly higher than in the baseline MRI (P < 0.001). Normalized choline was increased within the SS in all patients with de novo CE (n = 6). De-novo CE appeared within the SS in all patients (96% of all slices). This implies that the SS might indicate the site of future CE tumor, which represents the area of tumor growth after neurosurgery.

Metabolism and regional cerebral blood volume in autoimmune inflammatory demyelinating lesions mimicking malignant gliomas.

Dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI) and MR spectroscopy are thought to differentiate tumefactive autoimmune inflammatory demyelinating lesions from glial brain tumours. The aim of this work is to evaluate whether regional cerebral blood volume (rCBV), as well as choline (Cho), N-acetyl-aspartate (NAA) and myo-inositol (mIns) concentrations differ between tumefactive lesions and World Health Organization (WHO) grade II-III gliomas. Five patients with single autoimmune inflammatory demyelinating lesions and nine patients with WHO grade II and III gliomas were examined by DSC-MRI and by two-dimensional (2D) 1H MR spectroscopic imaging (1H-MRSI). rCBV values and metabolite concentrations were normalised to the respective values of the contralateral hemisphere. Normalised rCBV in the tumefactive lesions (mean 2.89, range 1.98-6.74) was in the some high level as in gliomas (mean 2.77, range 1.43-6.22). 1H-MRSI revealed increased normalised choline concentrations in five of six examinations of autoimmune lesions (mean 1.4, range 1.06-1.8) and in eight of nine gliomas (mean 1.35, range 0.92-1.73). Tumefactive autoimmune inflammatory demyelinating lesions not only have imaging appearance of gliomas but may also imitate marked increase of rCBV and Cho in WHO grade II-III gliomas.

MR angiography in patients with subarachnoid hemorrhage: adequate to evaluate vasospasm-induced vascular narrowing?

The diagnosis of cerebral vasospasm (CVS) following subarachnoid hemorrhage (SAH) is still challenging. We evaluate the accuracy of time of flight MR angiography (TOF-MRA) to assess the arterial diameters of the circle of Willis in SAH patients with suspected CVS. MR examinations (1.5 Tesla) including 3D TOF-MRA with maximum intensity projections (MIP) and digital subtraction angiography (DSA) were performed within 24 h in 21 patients with acute aneurysmal SAH and suspicion of CVS. Arterial diameters of the circle of Willis including the distal internal carotid artery (ICA) were measured as ratios to the extradural ICA in standard projections. The diagnosis of CVS was established by comparing the luminal size of baseline and follow-up DSA. The correlation between the arterial ratios measured on MIP angiograms and on follow-up DSA was assessed with Pearson's linear regression analysis. Arterial ratios on MIP angiograms were categorized as correct, overestimated, and underestimated compared to the ratios on follow-up DSA. Pearson's correlation coefficient between the ratios of MIP angiograms and DSA was r = 0.5799 and the regression coefficient was b = 0.4775. Highest correlation was found for the category of severe CVS (r = 0.8201). Of all MIP angiograms, 34.9% showed consistent results compared to the DSA, while 44.2% of MIP images overestimated the vascular narrowing. Standard MIP angiograms from TOF-MRA are not accurate to assess vascular narrowing in patients with suspected CVS after aneurysmal SAH. The multifocal arterial stenoses in CVS may induce severe changes in blood flow dynamics, which compromise the diagnostic accuracy of the TOF-MRA.

Leptomeningeal metastases in pediatrics: magnetic resonance image manifestations and correlation with cerebral spinal fluid cytology.

BACKGROUND: Detection of leptomeningeal metastases is fundamental to a complete evaluation of central nervous system (CNS) or non-CNS tumor with suspected involvement of the neuroaxis. Our purpose was to assess the appearances of different magnetic resonance (MR) sequences in the diagnosis of leptomeningeal metastases and correlate those positive findings with the cerebral spinal fluid (CSF) cytology results. METHODS: The authors reviewed the medical records and MR image manifestations of leptomeningeal metastases from 18 children who had positive MR findings and retrospectively correlated them with CSF cytologic results. There was a uniform MR protocol and the patients were examined with the same sequences. RESULTS: The abnormalities included pial-arachnoid disease (n = 16), disease coating the nerves (n = 12), hydrocephalus (n = 3) and subependymal metastases (n = 2). Enhanced T1 images were better than unenhanced fluid attenuated inversion recovery (FLAIR) and T2 to delineate cranial and spinal leptomeningeal metastases. In our sample, seven out of 18 cases were cytologically negative on a single lumbar puncture. CONCLUSIONS: Contrast-enhanced MR imaging can be invaluable, detecting the false-negative lumbar punctures. FLAIR and diffusion images can be helpful in diagnosing leptomeningeal metastases of non-enhancing primary tumors. Prognosis was more related to the primary tumor type than to the leptomeningeal enhancement MR pattern.

Diffusion tensor imaging in patients with adult chronic idiopathic hydrocephalus.

OBJECTIVE: Diffusion tensor imaging (DTI) parameters were investigated in patients with chronic idiopathic hydrocephalus to evaluate microstructural changes of brain tissue caused by chronic ventricular dilatation. METHODS: Eleven patients fulfilling the criteria for possible or probable idiopathic normal pressure hydrocephalus and 10 healthy control subjects underwent MRI at 3 Tesla, including DTI with 12 gradient directions. Patients were scanned before lumbar cerebrospinal fluid (CSF) withdrawal tests. Differences in fractional anisotropy (FA) and mean diffusivity (MD) between patients and controls were assessed using 2 different methods: manual definition of regions of interest and a fully automated method, TBSS (Tract-Based Spatial Statistics). DTI parameters were correlated with clinical findings. RESULTS: Compared with the control group, patients with chronic idiopathic hydrocephalus had significantly higher MD values in both the periventricular corticospinal tract (CST) and the corpus callosum (CC), whereas FA values were significantly higher in the CST but lower in the CC. DTI parameters of the CST correlated with the severity of gait disturbances. CONCLUSION: Microstructural changes in periventricular functionally relevant white matter structures (CSF, CC) in chronic idiopathic hydrocephalus can be visualized using DTI. Further studies should investigate the change of DTI parameters after CSF shunting and its relation to neurologic outcome.

Toxic leukoencephalopathy after heroin abuse without heroin vapor inhalation: MR imaging and clinical features in three patients.

BACKGROUND AND PURPOSE: Toxic leukoencephalopathy has been associated with illicit heroin vapor inhalation. Despite the nonspecific and variable clinical presentation of these patients, they show typical radiologic findings. Previous studies evaluated typical radiologic findings with symmetric infratentorial hyperintense signal changes and similar alteration in the posterior limb of the internal capsule, the splenium of corpus callosum, the medial lemniscus and the lateral brainstem. In context with the reviewed literature, a series of another three cases with toxic leukoencephalopathy after heroin abuse other than vapor inhalation is presented. PATIENTS AND METHODS: All three patients underwent magnet resonance imaging (MRI) including additional diffusion- weighted imaging and apparent diffusion coefficient maps. Clinical and laboratory findings were recorded. RESULTS: MRI of all three patients revealed similar symmetric supratentorial hyperintense signal changes involving the frontal, parietal, occipital and temporal lobes. The cortex was spared and the subcortical U fibers were partially involved. Further, the brainstem and the cerebellar white matter were not affected. CONCLUSION: Toxic leukoencephalopathy without involvement of the cerebellum and brainstem is a rare complication of heroin abuse. The pattern of heroin-induced toxic leukoencephalopathy on MRI might not only be related to an unknown adulterant, but also to the mode of drug administration.

The role of magnetic resonance imaging in children with hematogenous brain metastases from primary solid tumors.

Within a 10-year period, 4 out of 429 children with solid tumors treated at the pediatric oncology department developed brain metastases. Lesions secondary to direct extension from the skull or dura were excluded. The tumors causing brain metastases were non-small cell lung carcinoma, Wilms' tumor, osteosarcoma, und hepatoblastoma. All patients had single brain metastasis. All tumors were subcortical/cortical based and isointense on T1-images and, in 2 cases, mildly hyperintense on T2-images. Two patients showed diffusion abnormalities. Three showed enhancement. In the patient with osteosarcoma, metastasis was calcified. Central nervous system (CNS) metastasis may not in itself be a terminal event; metastasis in patients with Wilms' tumor might behave differently. Neuroimaging should be considered in children with pediatric solid tumors with neurological symptoms on follow up.

The striate sign: peritumoural perfusion pattern of infiltrative primary and recurrent gliomas.

MR perfusion depicts angiogenesis as a key factor for growth and malignancy in gliomas by means of increased regional cerebral blood volume (rCBV). The rCBV increase is not limited to the tumour area, but may also produce a stripe-like pattern of peritumoural rCBV increase that we defined as the "striate sign". We evaluated if prior radiochemotherapy influences perfusion values and pattern in and adjacent to malignant gliomas comparing rCBV of treated recurrent gliomas with untreated gliomas. Ninety-three patients with primary or recurrent WHO grades II-IV glial tumours underwent T2*-weighted dynamic susceptibility-weighted contrast-enhanced (DSC)-MRI. Differences of normalised rCBV and rCBV(max) were evaluated using Kruskal-Wallis analysis with post hoc tests. The number of cases showing a hot spot of rCBV (rCBV(max)) and/or a peritumoural striate pattern of rCBV increase (striate sign) was assessed and evaluated by Fisher's exact test. Significance level was determined as p < 0.05. Normalised rCBV, rCBV(max) and number of cases with the striate sign were significantly lower in recurrent (rCBV = 3.24 +/- 1.22, rCBV(max) = 5.05 +/- 2.27 and striate sign = 10/24) compared to primary WHO grade IV tumours (rCBV = 4.44 +/- 1.39, rCBV(max) = 7.31 +/- 3.0 and striate sign = 17/21, respectively). There were fewer cases with a striate sign in treated recurrent WHO grade III tumours than in untreated malignant transformed WHO grade II tumours. The pattern and degree of rCBV increase in and around gliomas differ between untreated and previously treated tumours. These differences might be due to post-therapeutic changes of the tumour-associated microvasculature by radiochemotherapy. Spectroscopic and susceptibility-weighted MR imaging may provide further insights into the tumour biology.

Cerebral gliomas: diffusional kurtosis imaging analysis of microstructural differences.

PURPOSE: To characterize the non-Gaussian diffusion patterns of cerebral glioma microstructure with respect to the different glioma grades by using a new method called diffusional kurtosis (DK) imaging. MATERIALS AND METHODS: In this study with institutional review board approval and patient consent, diffusional measures of mean kurtosis (MK), fractional anisotropy (FA), and apparent diffusion coefficient (ADC) were compared prospectively. Data were normalized to the contralateral white matter. A Mann-Whitney test was used to compare each histologic glioma subtype regarding the diffusion measurements. Receiver operating characteristic curves were used to test for the parameter with the best sensitivity and specificity for glioma grade discrimination. RESULTS: In 34 patients with cerebral gliomas (five World Health Organization [WHO] grade II astrocytomas, 13 WHO grade III astrocytomas, and 16 WHO grade IV glioblastomas multiforme), significantly different diffusion patterns were found among the three glioma groups. MK values increased with higher glioma malignancy, whereas ADCs tended to decrease with higher malignancy; FA values did not differ significantly among tumor groups. Significant differences between astrocytoma grades WHO II and WHO III were demonstrated only by DK values. Area under the receiver operating characteristic curve was highest for normalized MK (0.972) during testing to discriminate between low- and high-grade gliomas. CONCLUSION: This study demonstrates specific diffusion patterns for low- and high-grade gliomas, showing that DK imaging is able to depict microstructural changes within glioma tissue and is able to help differentiate among glioma grades. (c) RSNA, 2010.

Phosphorus and proton magnetic resonance spectroscopy demonstrates mitochondrial dysfunction in early and advanced Parkinson's disease.

Mitochondrial dysfunction hypothetically contributes to neuronal degeneration in patients with Parkinson's disease. While several in vitro data exist, the measurement of cerebral mitochondrial dysfunction in living patients with Parkinson's disease is challenging. Anatomical magnetic resonance imaging combined with phosphorus and proton magnetic resonance spectroscopic imaging provides information about the functional integrity of mitochondria in specific brain areas. We measured partial volume corrected concentrations of low-energy metabolites and high-energy phosphates with sufficient resolution to focus on pathology related target areas in Parkinson's disease. Combined phosphorus and proton magnetic resonance spectroscopic imaging in the mesostriatal region was performed in 16 early and 13 advanced patients with Parkinson's disease and compared to 19 age-matched controls at 3 Tesla. In the putamen and midbrain of both Parkinson's disease groups, we found a bilateral reduction of high-energy phosphates such as adenosine triphophosphate and phosphocreatine as final acceptors of energy from mitochondrial oxidative phosphorylation. In contrast, low-energy metabolites such as adenosine diphophosphate and inorganic phosphate were within normal ranges. These results provide strong in vivo evidence that mitochondrial dysfunction of mesostriatal neurons is a central and persistent phenomenon in the pathogenesis cascade of Parkinson's disease which occurs early in the course of the disease.

Intracranial stenting of atherosclerotic stenoses: current status and perspectives.

The purpose of this review article is to give an overview of the current development of intracranial stenting for treatment of atherosclerotic stenoses. Natural history and methods for diagnostic imaging are described as basis for the indication for endovascular treatment. Target group are patients with high-grade symptomatic stenoses > 70%. Technical standards for the use of self-expanding and balloon-expandable stents are reported together with the results of clinical case series. It seems to be difficult to drop acute complication rates (procedure-related stroke and death during the first 30 days) reliably from current levels of around 10% to values < 6%, which are more acceptable for a prophylactic procedure for the prevention of stroke. High restenosis rates up to 30% in the 1st year raised concerns about long-term efficacy. Further technical developments and improved criteria for patient selection are necessary to make intracranial stenting safer and more effective before a randomized trial (stent vs. medical treatment) may prove superiority of the endovascular approach.

Conversion to dementia in mild cognitive impairment is associated with decline of N-actylaspartate and creatine as revealed by magnetic resonance spectroscopy.

The purpose of the present study was to longitudinally track changes of metabolite markers detectable by magnetic resonance spectroscopy (MRS) in subjects with mild cognitive impairment (MCI) and to analyze these changes with respect to the rate of cognitive decline and clinical disease progression. Fifteen subjects with MCI and 12 healthy elderly controls were investigated longitudinally (average follow-up period: 3.4 years) using absolute quantification of metabolites within the mid-parietal grey matter and the parietal white matter [N-acetylaspartate (NAA), myo-inositol, choline, creatine, glutamine)] Our main findings include that a longitudinal decline in cognitive function (particularly in memory function) within the MCI group was predicted by a decline in absolute concentrations of the metabolic markers NAA and creatine. This effect was mainly explained by a significant decrease of NAA and creatine in those MCI subjects who converted to Alzheimer's dementia (AD) during the follow-up period. No differences were found at baseline between MCI converters and stable subjects, indicating that at least in the present study MRS did provide a predictive discrimination between converters and stable subjects. Our findings support the use of MRS as a tool for objectively monitoring disease progression even during the earliest stages of AD.

A standardised evaluation of pre-surgical imaging of the corticospinal tract: where to place the seed ROI.

The aim of the study was to compare the different approaches of pre-operative diffusion-tensor-imaging-based fibre tracking (FT) of the corticospinal tract (CST) focusing on the positioning of the seeding region of interest (seed ROI). Thirty-nine patients with brain lesions in the vicinity of the CST were evaluated pre-operatively. Imaging comprised a 3D T1-weighted sequence, a gradient echo echo-planar imaging sequence for functional magnetic resonance imaging (fMRI), and a diffusion-weighted sequence for diffusion tensor (DT) tractography. DT tractography was performed with two different procedures to track the corticospinal fibres: one downwards and one upwards. Downward FT was started with the seed ROI in the pre-central gyrus subjacent to the maximal fMRI activity while for the upward FT seed ROI was placed in the cerebral peduncle. In 16 patients, tracking results were individually compared with the unaffected contralateral hemisphere. Results were correlated with fractional anisotropy (FA) values and other factors potentially influencing fibre tracking results. On the side with the space-occupying lesion, downward FT yielded more positive tracking results (tracked fibres > 0) than the upward FT. On both the affected and the unaffected side, downward FT reconstructed fewer fibres than upward FT. For none of the two methods did the tracking results (number and volume of fibres) correlate with FA values or with other clinical data. FA values for tracts ipsilateral to the lesion correlated with age and lesion entity. We conclude that the sequence of ROI positioning influences significantly the tracking results. Upward FT may fail to track fibres, whereas the successful tracking results may be superior to downward FT. Hence, upward FT of the CST should be preferred in patients with space-occupying lesions. Downward FT should be performed if upward FT fails.

Evaluation of angiographic and technical aspects of carotid stenting with diffusion-weighted magnetic resonance imaging.

The detection of clinically silent ischemic lesions on postprocedural diffusion-weighted magnetic resonance images has become a preferred method for the description of embolic risks. The purpose of this single-center study was to evaluate whether diffusion-weighted imaging (DWI) could determine material related or technical risk factors of filter-protected carotid stenting. Eighty-four patients with symptomatic severe (> or = 60%) carotid artery stenoses received filter-protected carotid stenting. Standard DWI (b = 1000) was performed within 48 h before and after carotid stenting. The occurrence and load of new postinterventional DWI lesions were assessed. Multivariate analysis was performed to determine risk factors associated with DWI lesions, with emphasis on technical factors such as use of different access devices (guiding catheter method vs. long carotid sheath method), type of stent (open-cell nitinol stent vs. closed-cell Wallstent), and protective device (filters with 80-microm vs. 110-120-microm pore size). Markers for generalized atherosclerosis and for degree and site of stenosis were assessed to allow comparison of adequate risk profiles. Access, protective device, and stent type were not significantly associated with new embolic DWI lesions when we compared patients with equivalent risk profiles (long carotid sheath method 48% [11 of 23] vs. guiding catheter method 44% [27 of 61], Wallstent 47% [15 of 32] vs. nitinol stent 44% [23 of 52], and small pore size filter 61% [11 of 18] vs. large pore size filter 41% [27 of 66]). Single-center DWI studies with a moderate number of cases are inadequate for proper assessment of the embolic risk of technical- or material-related risk factors in carotid stenting. Larger multicenter studies with more cases are needed.

Coil embolization of cavernous sinus in patients with direct and dural arteriovenous fistula.

To determine technical success and acute complication rates after endovascular coil packing of the cavernous sinus. Nineteen patients presented with either direct (13) or dural (6) arteriovenous fistula (AVF) and were treated by means of coil embolization of the cavernous sinus. The aim of treatment was complete obliteration of the fistula. In a retrospective study, the degree of obliteration, regression of symptoms as well as complication rates were evaluated. Initial complete obliteration was achieved in 12 patients, subtotal occlusion of the sinus in 6 and incomplete packing with major residual fistula in 1 of the patients. Retreatment was successfully performed in two patients with early recurrence of AVF. Follow-up showed complete occlusion rates in 16 and subtotal obliteration in 3 patients. Chemosis and exophthalmus regressed rapidly in all affected patients. Persistence of cranial nerve deficits was observed in 11 cases. Postinterventional thrombosis of the ophthalmic vein was the only major acute complication (n = 2). Coil embolization of the cavernous sinus in cases with AVF is a complex procedure that is technically feasible and safe in the majority of cases. Adequate anticoagulation is recommended to avoid thrombembolic complications. Long-term outcome has to be determined by further studies.