4D-DSA for Assessment of the Angioarchitecture and Grading of Cranial Dural AVF.

BACKGROUND AND PURPOSE: Time-resolved 3D rotational angiography (4D-DSA) has been used to demonstrate details of the angioarchitecture of AVM, whereas it has rarely been used to describe features of dural AVF. In this exploratory study, we analyzed dural AVFs with a novel 4D software prototype, developed and provided by Siemens, to determine whether identification of the location of the fistulous point, grading, and treatment planning were feasible. MATERIALS AND METHODS: 4D-DSA volumes were calculated from existing 3D rotational angiography data sets of patients with dural AVFs. The 4D-DSA volumes were displayed in a virtual DSA mode and MPR or MIP in 3 orthogonal planes and compared with 2D-DSA by 2 experienced neuroradiologists. Fusions with unenhanced CT or MR images were used to improve visualization of adjacent anatomic structures. RESULTS: Comparison with 2D-DSA showed that evaluation of the fistulous point and grading according to the classification of Borden, Cognard, or Barrow was feasible in 26 of 27 cases. In 8 of 27 cases, 4D-DSA was considered advantageous for determining the fistulous point and the course of the draining vein in the dural AVF with cortical venous drainage, especially in the frontoethmoidal and frontoparietal regions. In 6 cases, the display of angioarchitecture was considered inferior to that of 2D-DSA due to motion artifacts, suboptimal selection of the injected vessel, and lack of temporal resolution. CONCLUSIONS: Detailed analysis of dural AVFs according to the standardized display of 4D-DSA volumes was feasible and helpful in understanding the angioarchitecture in selected cases. Further improvement and validation of the 4D software should solidify the complementary role of 4D-DSA to conventional 2D-DSA series.

Gliosarcoma with extensive extracranial metastatic spread and familial coincidence: A case report.

Gliosarcoma is a rare histopathological subtype of glioblastoma. Metastatic spreading is unusual. In this report, we illustrate a case of gliosarcoma with extensive extracranial metastases with confirmation of histological and molecular concordance between the primary tumor and a metastatic lesion of the lung. Only the autopsy revealed the extent of metastatic spread and the hematogenous pattern of metastatic dissemination. Moreover, the case bared a familial coincidence of malignant glial tumors as the patient's son was diagnosed with a high-grade glioma shortly after the patient's death. By molecular analysis (Sanger and next generation panel sequencing), we could confirm that both patient's tumors carried mutations in the TP53 gene. Interestingly, the detected mutations were located in different exons. Altogether, this case draws attention to the fact that sudden clinical aggravation could be caused by the rare phenomenon of metastatic spread and should therefore be always taken into consideration, even at an early disease stage. Furthermore, the presented case highlights the contemporary value of autoptic pathological examination.

Retrospective Analysis of the Association of a Small Vestibular Aqueduct with Cochleovestibular Symptoms in a Large, Single-Center Cohort Undergoing CT.

BACKGROUND AND PURPOSE: Temporal bones in some patients with Ménière disease have demonstrated small vestibular aqueducts; however, the prevalence and clinical importance of small vestibular aqueducts remain unclear in patients without Ménière disease. This study correlates the presence of a small vestibular aqueduct with cochleovestibular symptoms. MATERIALS AND METHODS: Consecutive temporal bone CTs in adults from January to December 2020 were reviewed. The midpoint vestibular aqueduct size in the 45°-oblique Pöschl view was measured by 2 reviewers independently in 684 patients (1346 ears). Retrospective chart review for the clinical diagnosis of Ménière disease, the presence of cochleovestibular symptoms, and indications for CT was performed. RESULTS: Fifty-two of 684 patients (7.6% of patients, 62/1346 ears) had small vestibular aqueducts. Twelve patients (15/1346 ears) had Ménière disease. Five of 12 patients with Ménière disease (5 ears) had a small vestibular aqueduct. There was a significant correlation between a small vestibular aqueduct and Ménière disease (P < .001). There was no statistical difference between the small vestibular aqueduct cohort and the cohort with normal vestibular aqueducts (0.3-0.7 mm) regarding tinnitus (P = .06), hearing loss (P = .88), vertigo (P = .26), dizziness (P = .83), and aural fullness (P = .61). CONCLUSIONS: While patients with Ménière disease were proportionately more likely to have a small vestibular aqueduct than patients without Ménière disease, the small vestibular aqueduct was more frequently seen in patients without Ménière disease and had no correlation with hearing loss, vertigo, dizziness, or aural fullness. We suggest that the finding of a small vestibular aqueduct on CT could be reported by radiologists as a possible finding in Ménière disease, but it remains of uncertain, and potentially unlikely, clinical importance in the absence of symptoms of Ménière disease.

Heterotopia in Individuals with 22q11.2 Deletion Syndrome.

BACKGROUND AND PURPOSE: MR imaging studies and neuropathologic findings in individuals with 22q11.2 deletion syndrome show anomalous early brain development. We aimed to retrospectively evaluate cerebral abnormalities, focusing on gray matter heterotopia, and to correlate these with subjects' neuropsychiatric impairments. MATERIALS AND METHODS: Three raters assessed gray matter heterotopia and other morphologic brain abnormalities on 3D T1WI and T2*WI in 75 individuals with 22q11.2 deletion syndrome (27 females, 15.5 [SD, 7.4] years of age) and 53 controls (24 females, 12.6 [SD, 4.7] years of age). We examined the association among the groups' most frequent morphologic findings, general cognitive performance, and comorbid neuropsychiatric conditions. RESULTS: Heterotopia in the white matter were the most frequent finding in individuals with 22q11.2 deletion syndrome (n = 29; controls, n = 0; between-group difference, P < .001), followed by cavum septi pellucidi and/or vergae (n = 20; controls, n = 0; P < .001), periventricular cysts (n = 10; controls, n = 0; P = .007), periventricular nodular heterotopia (n = 10; controls, n = 0; P = .007), and polymicrogyria (n = 3; controls, n = 0; P = .3). However, individuals with these morphologic brain abnormalities did not differ significantly from those without them in terms of general cognitive functioning and psychiatric comorbidities. CONCLUSIONS: Taken together, our findings, periventricular nodular heterotopia or heterotopia in the white matter (possibly related to interrupted Arc cells migration), persistent cavum septi pellucidi and/or vergae, and formation of periventricular cysts, give clues to the brain development disorder induced by the 22q11.2 deletion syndrome. There was no evidence that these morphologic findings were associated with differences in psychiatric or cognitive presentation of the 22q11.2 deletion syndrome.

Lower Lactate Levels and Lower Intracellular pH in Patients with IDH-Mutant versus Wild-Type Gliomas.

BACKGROUND AND PURPOSE: Preclinical evidence points toward a metabolic reprogramming in isocitrate dehydrogenase (IDH) mutated tumor cells with down-regulation of the expression of genes that encode for glycolytic metabolism. We noninvasively investigated lactate and Cr concentrations, as well as intracellular pH using 1H/phosphorus 31 (31P) MR spectroscopy in a cohort of patients with gliomas. MATERIALS AND METHODS: Thirty prospectively enrolled, mostly untreated patients with gliomas met the spectral quality criteria (World Health Organization II [n = 7], III [n = 16], IV [n = 7]; IDH-mutant [n = 23]; IDH wild-type [n = 7]; 1p/19q codeletion [n = 9]). MR imaging protocol included 3D 31P chemical shift imaging and 1H single-voxel spectroscopy (point-resolved spectroscopy sequence at TE = 30 ms and TE = 97 ms with optimized echo spacing for detection of 2-hydroxyglutarate) from the tumor area. Values for absolute metabolite concentrations were calculated (phantom replacement method). Intracellular pH was determined from 31P chemical shift imaging. RESULTS: At TE = 97 ms, lactate peaks can be fitted with little impact of lipid/macromolecule contamination. We found a significant difference in lactate concentrations, lactate/Cr ratios, and intracellular pH when comparing tumor voxels of patients with IDH-mutant with those of patients with IDH wild-type gliomas, with reduced lactate levels and near-normal intracellular pH in patients with IDH-mutant gliomas. We additionally found evidence for codependent effects of 1p/19q codeletion and IDH mutations with regard to lactate concentrations for World Health Organization tumor grades II and III, with lower lactate levels in patients exhibiting the codeletion. There was no statistical significance when comparing lactate concentrations between IDH-mutant World Health Organization II and III gliomas. CONCLUSIONS: We found indirect evidence for metabolic reprogramming in IDH-mutant tumors with significantly lower lactate concentrations compared with IDH wild-type tumors and a near-normal intracellular pH.

[Fast MRI sequences for clarification of acute neurological symptoms]. / Schnelle MRT-Sequenzen für die akute neurologische Abklärung.

CLINICAL/METHODICAL ISSUE: Neurological symptoms account for approximately 30% of emergency room (ER) visits. Clinical outcome often relies on a timely diagnosis and treatment initiation. Clinical imaging requirements are fast availability and high diagnostic value. STANDARD RADIOLOGICAL METHODS: Availability and quality of magnetic resonance imaging (MRI) in emergency rooms outside of core hours are limited compared to computed tomography (CT). Common reasons are infrastructural accessibility (hospitals using outpatient radiology centers), a lack of experienced and qualified staff and high patient compliance requirements. However, in a neurological emergency setting, MRI may show relevant advantages over CT in certain areas, such as diagnosis of stroke. METHODOLOGICAL INNOVATIONS: Advances in MRI technology have led to shorter exam times and robust motion reduction strategies. Common fast sequences and time reduction techniques for imaging of neurological emergencies are presented in this article. ACHIEVEMENTS: Recommendations for specific sequences or techniques depend on the institute's MRI hardware and software components. If available, parallel imaging is highly recommended for imaging of neurological emergencies. PRACTICAL RECOMMENDATIONS: Imaging of neurological emergencies requires fast, significant and motion insensitive standard acquisitions. Additional sequences should be acquired dependent on clinical and standard protocol imaging findings. An MRI emergency protocol is introduced for the most common neurologic emergencies including recommendations for fast MRI sequences and techniques for imaging time reduction.

Volumetry of Mesiotemporal Structures Reflects Serostatus in Patients with Limbic Encephalitis.

BACKGROUND AND PURPOSE: Limbic encephalitis is an autoimmune disease. A variety of autoantibodies have been associated with different subtypes of limbic encephalitis, whereas its MR imaging signature is uniformly characterized by mesiotemporal abnormalities across subtypes. Here, we hypothesized that patients with limbic encephalitis would show subtype-specific mesiotemporal structural correlates, which could be classified by supervised machine learning on an individual level. MATERIALS AND METHODS: T1WI MPRAGE scans from 46 patients with antibodies against glutamic acid decarboxylase and 34 patients with antibodies against the voltage-gated potassium channel complex (including 10 patients with leucine-rich glioma-inactivated 1 autoantibodies) and 48 healthy controls were retrospectively ascertained. Parcellation of the amygdala, hippocampus, and hippocampal subfields was performed using FreeSurfer. Volumes were extracted and compared between groups using unpaired, 2-tailed t tests. The volumes of hippocampal subfields were analyzed using a multivariate linear model and a binary decision tree classifier. RESULTS: Temporomesial volume alterations were most pronounced in an early stage and in the affected hemispheric side of patients. Statistical analysis revealed antibody-specific hippocampal fingerprints with a higher volume of CA1 in patients with glutamic acid decarboxylase-associated limbic encephalitis (P = .02), compared with controls, whereas CA1 did not differ from that in controls in patients with voltage-gated potassium channel complex autoantibodies. The classifier could successfully distinguish between patients with autoantibodies against leucine-rich glioma-inactivated 1 and glutamic acid decarboxylase with a specificity of 87% and a sensitivity of 80%. CONCLUSIONS: Our results suggest stage-, side- and antibody-specific structural correlates of limbic encephalitis; thus, they create a perspective toward an MR imaging-based diagnosis.

Cerebrovascular Reactivity during Prolonged Breath-Hold in Experienced Freedivers.

BACKGROUND AND PURPOSE: Experienced freedivers can endure prolonged breath-holds despite severe hypoxemia and are therefore ideal subjects to study apnea-induced cerebrovascular reactivity. This multiparametric study investigated CBF, the spatial coefficient of variation as a correlate of arterial transit time and brain metabolism, dynamics during prolonged apnea. MATERIALS AND METHODS: Fifteen male freedivers (age range, 20-64 years; cumulative previous prolonged breath-holds >2 minutes and 30 seconds: 4-79,200) underwent repetitive 3T pseudocontinuous arterial spin-labeling and 31P-/1H-MR spectroscopy before, during, and after a 5-minute breath-hold (split into early and late phases) and gave temporally matching venous blood gas samples. Correlation of temporal and regional cerebrovascular reactivity to blood gases and cumulative previous breath-holds of >2 minutes and 30 seconds in a lifetime was assessed. RESULTS: The spatial coefficient of variation of CBF (by arterial spin-labeling) decreased during the early breath-hold phase (-30.0%, P = .002), whereas CBF remained almost stable during this phase and increased in the late phase (+51.8%, P = .001). CBF differed between the anterior and the posterior circulation during all phases (eg, during late breath-hold: MCA, 57.3 ± 14.2 versus posterior cerebral artery, 42.7 ± 10.8 mL/100 g/min; P = .001). There was an association between breath-hold experience and lower CBF (1000 previous breath-holds reduced WM CBF by 0.6 mL/100 g/min; 95% CI, 0.15-1.1 mL/100 g/min; P = .01). While breath-hold caused peripheral lactate rise (+18.5%) and hypoxemia (oxygen saturation, -24.0%), cerebral lactate and adenosine diphosphate remained within physiologic ranges despite early signs of oxidative stress [-6.4% phosphocreatine / (adenosine triphosphate + adenosine diphosphate); P = .02]. CONCLUSIONS: This study revealed that the cerebral energy metabolism of trained freedivers withstands severe hypoxic hypercarbia in prolonged breath-hold due to a complex cerebrovascular hemodynamic response.

Effects of aerobic exercise on brain metabolism and grey matter volume in older adults: results of the randomised controlled SMART trial.

There is mounting evidence that aerobic exercise has a positive effect on cognitive functions in older adults. To date, little is known about the neurometabolic and molecular mechanisms underlying this positive effect. The present study used magnetic resonance spectroscopy and quantitative MRI to systematically explore the effects of physical activity on human brain metabolism and grey matter (GM) volume in healthy aging. This is a randomised controlled assessor-blinded two-armed trial (n=53) to explore exercise-induced neuroprotective and metabolic effects on the brain in cognitively healthy older adults. Participants (age >65) were allocated to a 12-week individualised aerobic exercise programme intervention (n=29) or a 12-week waiting control group (n=24). The main outcomes were the change in cerebral metabolism and its association to brain-derived neurotrophic factor (BDNF) levels as well as changes in GM volume. We found that cerebral choline concentrations remained stable after 12 weeks of aerobic exercise in the intervention group, whereas they increased in the waiting control group. No effect of training was seen on cerebral N-acetyl-aspartate concentrations, nor on markers of neuronal energy reserve or BDNF levels. Further, we observed no change in cortical GM volume in response to aerobic exercise. The finding of stable choline concentrations in the intervention group over the 3 month period might indicate a neuroprotective effect of aerobic exercise. Choline might constitute a valid marker for an effect of aerobic exercise on cerebral metabolism in healthy aging.

Imaging Biomarkers for Adult Medulloblastomas: Genetic Entities May Be Identified by Their MR Imaging Radiophenotype.

BACKGROUND AND PURPOSE: The occurrence of medulloblastomas in adults is rare; nevertheless, these tumors can be subdivided into genetic and histologic entities each having distinct prognoses. This study aimed to identify MR imaging biomarkers to classify these entities and to uncover differences in MR imaging biomarkers identified in pediatric medulloblastomas. MATERIALS AND METHODS: Eligible preoperative MRIs from 28 patients (11 women; 22-53 years of age) of the Multicenter Pilot-study for the Therapy of Medulloblastoma of Adults (NOA-7) cohort were assessed by 3 experienced neuroradiologists. Lesions and perifocal edema were volumetrized and multiparametrically evaluated for classic morphologic characteristics, location, hydrocephalus, and Chang criteria. To identify MR imaging biomarkers, we correlated genetic entities sonic hedgehog (SHH) TP53 wild type, wingless (WNT), and non-WNT/non-SHH medulloblastomas (in adults, Group 4), and histologic entities were correlated with the imaging criteria. These MR imaging biomarkers were compared with corresponding data from a pediatric study. RESULTS: There were 19 SHH TP53 wild type (69%), 4 WNT-activated (14%), and 5 Group 4 (17%) medulloblastomas. Six potential MR imaging biomarkers were identified, 3 of which, hydrocephalus (P = .03), intraventricular macrometastases (P = .02), and hemorrhage (P = .04), when combined, could identify WNT medulloblastoma with 100% sensitivity and 88.3% specificity (95% CI, 39.8%-100.0% and 62.6%-95.3%). WNT-activated nuclear ß-catenin accumulating medulloblastomas were smaller than the other entities (95% CI, 5.2-22.3 cm3 versus 35.1-47.6 cm3; P = .03). Hemorrhage was exclusively present in non-WNT/non-SHH medulloblastomas (P = .04; n = 2/5). MR imaging biomarkers were all discordant from those identified in the pediatric cohort. Desmoplastic/nodular medulloblastomas were more rarely in contact with the fourth ventricle (4/15 versus 7/13; P = .04). CONCLUSIONS: MR imaging biomarkers can help distinguish histologic and genetic medulloblastoma entities in adults and appear to be different from those identified in children.

[Interventional radiology in the head and neck region]. / Interventionelle Radiologie im Kopf-Hals-Bereich.

In interventional neuroradiology, endovascular embolization represents an important and helpful tool in the treatment of multiple head and neck diseases. These interventional procedures may be performed with curative intent, to reduce the surgical risk within a multimodal treatment concept, or to improve or at least maintain a good quality of life within a palliative therapy concept. In addition to a good understanding of disease pathology, knowledge of vascular anatomy, including collateral vessels and dangerous extracranial-intracranial anastomoses, is essential for successful treatment, as is implementation of an established technique using appropriate material. Indications for endovascular embolization are i. otherwise unmanageable bleeding (caused by e. g., trauma, vascular malformation, or tumor), ii. reduction of perioperative bleeding by preoperative embolization in case of a hypervascularized tumor, iii. selective induction of tumor necrosis by palliative embolization to enhance local tumor control. Major complications such as stroke, loss of vision, and cranial nerve palsy are mostly due to a lack of preinterventional evaluation. Regarding neurological deficits, interventions within the supply region of the external carotid artery have a complication rate below 1%.

[Magnetic resonance spectroscopy of brain tumors]. / MR-Spektroskopie bei Hirntumoren.

BACKGROUND: Conventional magnetic resonance imaging (MRI) under consideration of clinical information enables the correct diagnosis and therapy for the majority of cerebral space-occupying lesions. Some important differential diagnoses, e. g. low vs. high-grade tumors, require additional MRI methods. OBJECTIVE: This article critically discusses the importance of magnetic resonance spectroscopy (1H-MRS) in brain tumors. MATERIAL AND METHODS: The concentration of normal and pathological brain metabolites can be non-invasively measured by 1H-MRS. It is based on the principle that chemical proton compounds of certain brain metabolites focally attenuate the external magnetic field and change the proton resonance frequency according to typical patterns. In addition, parameter maps of MRS imaging (MRSI) can show the tumor heterogeneity as well as changes in the surrounding brain tissue. In this context, the patterns of N­acetylaspartate, total choline (tCho) and creatine are relatively robust, whereas the patterns of other metabolites, such as myoinositol, glutamate, lactate or lipids greatly depend on the external field strength and echo time. RESULTS: The signal intensity of tCho in vital tumor tissue increases with the WHO grade of the brain tumor, i.e. increases with the level of malignancy. The use of MRSI facilitates the WHO grading of gliomas by determining target points in biopsies. Different distribution patterns and specific metabolite signals enable a better differentiation between abscesses, metastases, central nervous system (CNS) lymphomas and gliomas. CONCLUSION: The use of 1H-MRS provides valuable information on the differential diagnosis and graduation of brain tumors; however, so far artefacts, signal strength, parameter selection and a lack of standardization impede the establishment of 1H-MRS for use in clinical routine diagnostics.

[Clinical magnetic resonance imaging : Frequent incidental cerebral findings]. / Klinische Magnetresonanztomographie : Häufige zerebrale Zufallsbefunde.

The increasing use of magnetic resonance imaging (MRI) in clinical diagnostics means that patients and physicians are confronted more often with incidental findings. In the literature there are fluctuating data on the incidence of such findings and guidelines concerning the further procedure exist in only very few cases, such as incidental aneurysms and pituitary adenomas. The diagnostic and therapeutic implications which can be derived from incidental findings depend on multiple factors, such as anatomical location, patient age, comorbidity and patient wishes. For this reason it often makes sense to refer patients with incidental findings to an interdisciplinary neurological center at an early stage. In this review frequent incidental cerebral findings, epidemiological data, imaging criteria and, where possible, recommendations for the further procedure are shown.

Post-Surgical Language Reorganization Occurs in Tumors of the Dominant and Non-Dominant Hemisphere.

PURPOSE: Surgical resection of brain tumors may shift the location of cortical language areas. Studies of language reorganization primarily investigated left-hemispheric tumors irrespective of hemispheric language dominance. We used functional magnetic resonance imaging (fMRI) to investigate how tumors influence post-surgical language reorganization in relation to the dominant language areas. METHODS: A total of, 17 patients with brain tumors (16 gliomas, one metastasis) in the frontotemporal and lower parietal lobes planned for awake surgery underwent pre-surgical and post-surgical language fMRI. Language activation post-to-pre surgery was evaluated visually and quantitatively on the statistically thresholded images on patient-by-patient basis. Results were qualitatively compared between three patient groups: temporal, with tumors in the dominant temporal lobe, frontal, with tumors in the dominant frontal lobe and remote, with tumors in the non-dominant hemisphere. RESULTS: Post-to-pre-surgical distributions of activated voxels changed in all except the one patient with metastasis. Changes were more pronounced in the dominant hemisphere for all three groups, showing increased number of activated voxels and also new activation areas. Tumor resection in the dominant hemisphere (frontal and temporal) shifted the activation from frontal towards temporal, whereas tumor resection in the non-dominant hemisphere shifted the activation from temporal towards frontal dominant areas. CONCLUSION: Resection of gliomas in the dominant and in the non-dominant hemisphere induces postsurgical shifts and increase in language activation, indicating that infiltrating gliomas have a widespread influence on the language network. The dominant hemisphere gained most of the language activation irrespective of tumor localization, possibly reflecting recovery of pre-surgical tumor-induced suppression of these activations.

Therapy of leptomeningeal metastasis in solid tumors.

Leptomeningeal metastasis (LM), i.e. the seeding of tumor cells to the cerebrospinal fluid (CSF) and the leptomeninges, is a devastating and mostly late-stage complication of various solid tumors. Clinical signs and symptoms may include cranial nerve palsies, radicular symptoms, signs of increased intracranial pressure such as headache, nausea and vomiting, and cognitive dysfunction. In cases of suspected LM, the highest diagnostic sensitivity is provided by the combination of CSF cytology and contrast-enhanced MRI (cranial as well as complete spine). The therapeutic spectrum includes radiotherapy of the clinically involved region as well as systemic and intrathecal chemotherapy. The choice of treatment modalities depends on the type of LM (non-adherent tumor cells in the CSF vs. nodular contrast-enhancing tumor growth), additional systemic involvement (uncontrolled vs. controlled systemic disease) and additional involvement of the CNS parenchyma (LM as the only CNS involvement vs. LM+parenchymal CNS metastases). Larger contrast-enhancing nodular LM or symptomatic lesions of the spine may be treated with radiotherapy. In case of uncontrolled systemic disease, the treatment regimen should include systemic chemotherapy. The choice of systemic treatment should take into account the histology of the primary tumor. Intrathecal chemotherapy is most important in cases of LM of the non-adherent type. There are three substances for routine use for intrathecal chemotherapy: methotrexate, cytarabine, and thiotepa. Liposomal cytarabine shows advantages in terms of longer injection intervals, a sufficient distribution in the entire subarachnoid space after lumbar administration and improved quality-of-life. The role of new agents (e.g. rituximab and trastuzumab) for intrathecal therapy is still unclear.

Functional hemispherectomy: postoperative motor state and correlation to preoperative DTI.

INTRODUCTION: Functional hemispherectomy (FH) is an infrequent method to reduce seizure frequency in patients with intractable epilepsy. The risk that hemispherotomy injures brain structures involved in residual motor function is challenging to predict. Our purpose was to evaluate MR diffusion tensor imaging (DTI) to preoperatively assess residual ipsilateral motor function prior to FH. METHODS: We applied DTI in 34 patients scheduled for FH to perform fiber tracking in healthy and damaged hemispheres of the corticospinal tracts (CSTs) and of the corpus callosum. We assessed the CSTs and the commissural fibers for streamline count, for fractional anisotropy (FA), and for respective ratios (affected/unaffected side). We correlated these DTI values to post-to-prior changes of muscle strength and evaluated their diagnostic accuracy. RESULTS: FA of the affected CSTs and of commissural fibers was significantly higher in patients with postoperative loss of muscle strength compared to patients without (p = 0.014 and p = 0.008). In contrast, CST FA from healthy hemispheres was not different between both groups. Ratios of streamline counts and FA from CSTs were higher in patients with postoperative reduced muscle strength compared to those without (1.14 ± 0.22 vs. 0.58 ± 0.14, p = 0.040; 0.93 ± 0.05 vs. 0.74 ± 0.03, p = 0.003). CSTs' normalized FA ratio greater than -0.085 predicted loss of muscle strength with 80 % sensitivity and 69.6 % specificity. CONCLUSION: Preoperative tracking of the CST and of commissural fibers contributes to the prediction of postoperative motor outcome after functional hemispherectomy.

Quantitative MR Imaging of Brain Tissue and Brain Pathologies.

Measurement of basic quantitative magnetic resonance (MR) parameters (e.g., relaxation times T1, T2*, T2 or respective rates R (1/T)) corrected for radiofrequency (RF) coil bias yields different conventional and new tissue contrasts as well as volumes for tissue segmentation. This approach also provides quantitative measures of microstructural and functional tissue changes. We herein demonstrate some prospects of quantitative MR imaging in neurological diagnostics and science.

[Towards more precision in the therapy of brain tumors. Possibilities and limits of MRI]. / Auf dem Weg zu mehr Präzision in der Hirntumortherapie : Möglichkeiten und Grenzen der MR-Bildgebung.

Due to the introduction of advanced functional and spectroscopic magnetic resonance (MR) sequences, MR imaging has gained significant importance in neuro-oncology. In contrast to recent years when neuro-oncological imaging was mostly limited to contrast-enhanced T1-weighted images, advanced MR methods provide direct visualization and assessment of tumor pathophysiology. This article summarizes the most relevant MR methods for neuro-oncological imaging and highlights the pathophysiological background as well as potential clinical applications. Ultimately, this article gives a glimpse into the future and introduces potential applications of ultra-high field MRI.

[Interdisciplinary neuro-oncology: part 1: diagnostics and operative therapy of primary brain tumors]. / Interdisziplinäre Neuroonkologie : Teil 1: Diagnostik und operative Therapie primärer Gehirntumoren.

By combining the expertise of clinical neuroscience, the aim of neuro-oncology is to optimize diagnostic planning and therapy of primary brain tumors in an interdisciplinary setting together with radio-oncology and medical oncology. High-end imaging frequently allows brain tumors to be diagnosed preoperatively with respect to tumor entity and even tumor malignancy grade. Moreover, neuroimaging is indispensable for guidance of biopsy resection and monitoring of therapy. Surgical resection of intracranial lesions with preservation of neurological function is increasingly feasible. Tools to achieve this goal are, for example neuronavigation, functional magnetic resonance imaging (fMRI), tractography, intraoperative cortical stimulation and precise intraoperative definition of tumor margins by virtue of various techniques. In addition to classical histopathological diagnosis and tumor classification, modern neuropathology is supplemented by molecular characterization of brain tumors in order to provide clinicians with prognostic and predictive (of therapy) markers, such as codeletion of chromosomes 1p and 19q in anaplastic gliomas and O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation in glioblastomas. Although this is not yet individualized tumor therapy, the increasingly more detailed analysis of the molecular pathogenesis of an individual glioma will eventually lead to specific pharmacological blockade of disturbed intracellular pathways in individual patients. This article gives an overview of the state of the art of interdisciplinary neuro-oncology whereby part 1 deals with the diagnostics and surgical therapy of primary brain tumors and part 2 describes the medical therapy of primary brain tumors.