Ruptured basilar artery perforator aneurysms--treatment regimen and long-term follow-up in eight cases.

INTRODUCTION: Basilar artery (BA) perforator aneurysms may lead to severe subarachnoid hemorrhage (SAH). The acute management is uncertain. The anatomic approach is challenging both for coiling and clipping, and flow diverter stenting may be dangerous due to the required antiplatelet therapy. We report on our experiences in eight patients. METHODS: We retrospectively analyzed eight patients with ruptured BA perforator aneurysm, including clinical characteristics, imaging data, treatment regimen, clinical course, and long-term outcome. RESULTS: Patients presented with major SAH and World Federation of Neurosurgical Societies (WFNS) scores of I in three, II in two, and V in three cases. In four patients, the aneurysm was detected in the initial angiography, in four only in follow-up angiography. Five patients were treated conservatively and three patients had endovascular therapy. In the conservative group, the aneurysm spontaneously thrombosed in three cases. One patient suffered from a re-SAH and stayed permanently dependent due to an associated perforator stroke (modified Rankin Scale (mRS) 5). The remaining four patients recovered well (mRS 0 and 1 in two cases, each) including three patients also exhibiting perforator strokes. Regarding the endovascular group, one parent vessel was an angioma feeder and embolized with Onyx. The second aneurysm spontaneously thrombosed periinterventionally. The third patient underwent coiling. Two parent vessels were occluded postinterventionally, resulting in perforator strokes. Final mRS scores were 0, 2, and 2, respectively. CONCLUSION: Conservative management of ruptured BA aneurysms might be a first-line treatment option with common spontaneous aneurysm occlusion, low rate of re-SAH, and promising clinical outcome.

Pseudo-subarachnoid haemorrhage due to chronic hypoxaemia: case report and review of the literature.

BACKGROUND: The specificity of computed tomography (CT) for subarachnoid haemorrhage (SAH) is very high. However, physicians should be aware of rare false positive findings, also referred to as "pseudo-SAH". We present an unusual case in which such a finding was caused by chronic hypoxaemia. CASE PRESENTATION: A 37-year-old male patient presented with headaches. His CT-scan showed multiple confluent subarachnoid hyperattenuations, which mimicked SAH. However, the headache was chronic and had no features typical for SAH. The patient suffered from severe chronic hypoxaemia due to congenital heart failure. On CT-angiography diffuse intracranial vessel proliferation was found and laboratory results revealed a highly raised level of haematocrit, which had both probably developed as compensatory mechanisms. A combination of these findings explained the subarachnoid hyperdensities. Magnetic resonance imaging (MRI) showed no signs of SAH and visualized hypoxaemia in cerebral veins. A diagnosis of pseudo-SAH was made. The patient's symptoms were likely due to a secondary headache attributed to hypoxia and/or hypercapnia. Therapy was symptomatic. CONCLUSIONS: Severe chronic hypoxaemia should be recognised as a rare cause of pseudo-SAH. Clinical evaluation and MRI help differentiate SAH from pseudo-SAH.

Multimodal recanalization therapy in acute basilar artery occlusion: long-term functional outcome and quality of life.

BACKGROUND AND PURPOSE: Multimodal recanalization therapy in patients with acute basilar artery occlusion provides high recanalization rates. A substantial subset of treated patients survives with only minor or moderate functional handicap. However, long-term functional outcome and quality of life in these patients have rarely been systematically analyzed. METHODS: In this monocentric retrospective study, we analyzed mortality, long-term functional outcome (modified Rankin Scale), and quality of life (36-Item Short-Form Health Survey questionnaire) in all consecutive patients who had been treated for acute basilar artery occlusion in our institution between December 2002 and December 2009. RESULTS: Ninety-one patients (57 male; median age, 65 years; range, 20-89 years) were treated by multimodal recanalization therapy. This included intravenous thrombolysis (n=32) with consecutive on-demand intra-arterial therapy (n=23) or intra-arterial therapy alone (n=59). The overall recanalization rate was 89%. After a median observation time of 4.2 years (range, 0.5-7.4 years), the mortality rate was 59%. Among the 35 survivors, 26 patients (74%) had a good or moderate long-term functional outcome (modified Rankin Scale ≤3). Health-related quality of life was better than that of unselected patients with stroke. Backward stepwise logistic regression identified intravenous thrombolysis (P=0.002) and female sex (P=0.001) as predictors of favorable functional long-term outcome (modified Rankin Scale ≤3). Coma at admission (Glasgow Coma Scale ≤8) was associated with poor outcome (modified Rankin Scale ≥4; P=0.036). CONCLUSIONS: Long-term survival is achieved in approximately 40% of patients with basilar artery occlusion treated with multimodal recanalization therapy. Approximately 75% of the survivors have a favorable functional long-term outcome with an acceptable quality of life.

Enhanced analysis of intracerebral arterioveneous malformations by the intraoperative use of analytical indocyanine green videoangiography: technical note.

In cerebral arterioveneous malformations (AVMs) detailed intraoperative identification of feeding arteries, nidal vessels and draining veins is crucial for surgery. Intraoperative imaging techniques like indocyanine green videoangiography (ICG-VAG) provide information about vessel architecture and patency, but do not allow time-dependent analysis of intravascular blood flow. Here we report on our first experiences with analytical indocyanine green videoangiography (aICG-VAG) using FLOW 800 software as a useful tool for assessing the time-dependent intraoperative blood flow during surgical removal of cerebral AVMs. Microsope-integrated colour-encoded aICG-VAG was used for the surgical treatment of a 38-year-old woman diagnosed with an incidental AVM, Spetzler Martin grade I, of the left frontal lobe and of a 26-year-old man suffering from seizures caused by a symptomatic AVM, Spetzler Martin grade III, of the right temporal lobe. Analytical ICG-VAG visualization was intraoperatively correlated with in situ micro-Doppler investigation, as well as preoperative and postoperative digital subtraction angiography (DSA). Analytical ICG-VAG is fast, easy to handle and integrates intuitively into surgical procedures. It allows colour-encoded visualization of blood flow distribution with high temporal and spatial resolution. Superficial major and minor feeding arteries can be clearly separated from the nidus and draining veins. Effects of stepwise vessel obliteration on velocity and direction of AVM blood flow can be objectified. High quality of visualization, however, is limited to the site of surgery. Colour-encoded aICG-VAG with FLOW 800 enables intraoperative real-time analysis of arterial and venous vessel architecture and might, therefore, increase efficacy and safety of neurovascular surgery in a selected subset of superficial AVMs.

Drip, ship, and retrieve: cooperative recanalization therapy in acute basilar artery occlusion.

BACKGROUND AND PURPOSE: In acute basilar artery occlusion, intra-arterial thrombolysis or endovascular mechanical recanalization may result in higher recanalization rates than intravenous thrombolysis. However, many patients are admitted to community hospitals, where endovascular therapy is usually not readily available. We initiated a "drip, ship, and retrieve" cooperative treatment protocol in 2006, in which thrombolysis was initiated in the community hospital with simultaneous referral to our stroke center and the use of endovascular mechanical recanalization as required. METHODS: The outcome of all consecutive patients treated by this protocol between 2006 and June 2009 was compared with that of a similar population of referred patients who had received primary intra-arterial therapy with or without tirofiban bridging at our center between 2003 and 2005. RESULTS: In both groups, 26 patients were identified. The rate of symptomatic intracranial hemorrhage was 12% in previous patients and 8% in those treated under the new protocol. Recanalization rates were similar: 92% in previous patients and 85% with the new protocol; 38% of these had recanalization after intravenous thrombolysis alone. Functional outcome was better among those treated with the new protocol, with more patients achieving a modified Rankin scale score < or = 2 (38% versus 12%; P=0.03) and < or = 3 (50% versus 23%; P=0.04). CONCLUSIONS: "Drip, ship, and retrieve" seems to be feasible and safe in acute basilar artery occlusion. Patients appear to benefit from initiation of intravenous thrombolysis in the community hospital before transfer. Randomized controlled trials will have to confirm the expected benefit of subsequent on-demand mechanical recanalization on clinical outcome.

Real versus imagined locomotion: a [18F]-FDG PET-fMRI comparison.

The cortical, cerebellar and brainstem BOLD-signal changes have been identified with fMRI in humans during mental imagery of walking. In this study the whole brain activation and deactivation pattern during real locomotion was investigated by [(18)F]-FDG-PET and compared to BOLD-signal changes during imagined locomotion in the same subjects using fMRI. Sixteen healthy subjects were scanned at locomotion and rest with [(18)F]-FDG-PET. In the locomotion paradigm subjects walked at constant velocity for 10 min. Then [(18)F]-FDG was injected intravenously while subjects continued walking for another 10 min. For comparison fMRI was performed in the same subjects during imagined walking. During real and imagined locomotion a basic locomotion network including activations in the frontal cortex, cerebellum, pontomesencephalic tegmentum, parahippocampal, fusiform and occipital gyri, and deactivations in the multisensory vestibular cortices (esp. superior temporal gyrus, inferior parietal lobule) was shown. As a difference, the primary motor and somatosensory cortices were activated during real locomotion as distinct to the supplementary motor cortex and basal ganglia during imagined locomotion. Activations of the brainstem locomotor centers were more prominent in imagined locomotion. In conclusion, basic activation and deactivation patterns of real locomotion correspond to that of imagined locomotion. The differences may be due to distinct patterns of locomotion tested. Contrary to constant velocity real locomotion (10 min) in [(18)F]-FDG-PET, mental imagery of locomotion over repeated 20-s periods includes gait initiation and velocity changes. Real steady-state locomotion seems to use a direct pathway via the primary motor cortex, whereas imagined modulatory locomotion an indirect pathway via a supplementary motor cortex and basal ganglia loop.

Sensitivity and reliability of language laterality assessment with a free reversed association task--a fMRI study.

OBJECTIVE: The aim of the study was to evaluate the sensitivity and reliability of assessing hemispheric language dominance with functional magnetic resonance imaging (fMRI) using a 'free reversed association task.' METHODS: Thirty-nine healthy subjects (13 dextrals, 13 sinistrals and 13 bimanuals) underwent two repeated fMRI sessions. In the active phases sets of words were presented via headphones, and an associated target item was named. During the baseline phases a standard answer was given after listening to unintelligible stimuli. Data were preprocessed with SPM, and then laterality indices (LI) and reliability coefficients (RC) were calculated. RESULTS: Extensive frontal, temporal and parietal activations were found. Seventy-eight percent of the subjects showed left-hemispheric dominance, 5% showed right-hemispheric dominance, and 17% had bilateral language representations. The incidence of right-hemispheric language dominance was 4.3 times higher in a left-hander with a handedness quotient (HQ) of -90 than in a right-hander with a HQ of +90. The RC was 0.61 for combined ROIs (global network). Strong correlations were found between the two session LIs (r = 0.95 for the global network). CONCLUSION: 'Free reversed association' is a sensitive and reliable task for the determination of individual language lateralization. This suggests that the task may be used in a clinical setting.

Patient reported long-term outcome after endovascular therapy of indirect dural carotid cavernous fistulas.

PURPOSE: Patient-reported long-term follow-up after endovascular treatment of indirect carotid cavernous fistulas is important, but rarely addressed in literature. We report on this issue with a special focus on the patient's view and its impact on the indication evaluation process. METHODS: We retrospectively reviewed the records of all patients (n = 33) with a minimum follow-up interval of at least 36 and up to 166 months after endovascular treatment of an indirect carotid cavernous fistula (Barrow B-D) at our institution (treated from 01/2003 to 06/2015). We determined treatment details including primary therapy success and complication rate and quote the patient's subjective perception of the long-term treatment success using a standardized interview form. RESULTS: As a primary result the fistula was completely occluded in 25/33 cases (76%), while a downgrading was achieved in 8/33 (24%) of the cases. Secondary occlusion was observed in three out of eight patients (38%). In the long-term interview (response rate: 91%, median follow-up interval: 114 months) 87% of the patients reported high satisfaction with the long-term therapy result. Endovascular treatment achieved a sustainable relief from all eye-related symptoms in 89% and from pulsatile tinnitus in 57% of the cases. CONCLUSIONS: In addition to good results in terms of angiographic and clinical cure, endovascular treatment is also perceived as beneficial by most of the patients. This is another important argument in favor of an endovascular treatment.

Echo time dependence of BOLD fMRI studies of the piriform cortex.

BACKGROUND AND PURPOSE: In functional magnetic resonance imaging (fMRI) studies, brain areas that are commonly associated with the processing of olfactory stimuli, i.e., piriform cortex and orbitofrontal cortex, are often obscured by susceptibility-induced signal loss. The authors hypothesized that using a short echo time (TE) should not only reduce susceptibility artifacts but also increase the overall signal-to-noise ratio and allow to retrieve a blood oxygenation level-dependent (BOLD) signal in regions normally affected by these artifacts. MATERIAL AND METHODS: Two sequences with TEs of 60 and 32 ms were compared using a 1.5-T MRI scanner: in a standard motor paradigm, activations of the contralateral motor cortex were measured. In an olfactory stimulation paradigm, activations in piriform cortex were compared. RESULTS: Reducing TE from 60 to 32 ms reduced the observed signal intensity changes in the motor paradigm by 51%. Concomitant to this, geometric distortions and signal dropout artifacts were decreased at orbitofrontal and temporomesial brain areas in both paradigms. Contrary to the authors' expectations, the signal intensity changes in the piriform cortex were also reduced by 48% in the olfactory paradigm. Moreover, piriform cortex activation was detected in less subjects at TE = 32 ms than at TE = 60 ms. Changes in cortical activation were significant in the right, but not in the left piriform cortex. CONCLUSION: Although a shorter TE reduces signal dropouts due to susceptibility artifacts, this shorter TE is not sufficient to recover the BOLD signal from regions affected by susceptibility artifacts such as the piriform cortex. Thus, reducing the TE to the T2* of the investigated region is not an effective approach to improve the results of olfactory fMRI studies.

Activation of primary and secondary somatosensory regions following tactile stimulation of the face.

BACKGROUND: Since the work of Penfield & Rasmussen it is well established that the human primary somatosensory cortex is organized somatotopically. However, the order of the representation of the face is still a matter of discussion, i.e., it is yet unclear whether the face is represented upside-down or vice versa in the somatosensory cortex. MATERIAL AND METHODS: In a functional magnetic resonance imaging study (n = 30), tactile stimuli to three different locations on each side of the face were applied using a pneumatic device. Locations of stimulation corresponded to the three branches of the trigeminal nerve (forehead, cheek, chin). To determine the representation of the face on primary and secondary somatosensory cortices, peak coordinates within these regions were analyzed subjectwise. RESULTS: Contralateral activation of the primary somatosensory cortex following tactile stimulation of the face was found, whereas the secondary somatosensory cortices were activated bilaterally. However, differences between activation coordinates of different tactile stimuli applied to one side of the face were not statistically significant. CONCLUSION: Tactile stimulation of the face leads to contralateral activation of primary and bilateral activation of secondary somatosensory cortices. Using the authors' methodological approach it was not possible to detect a somatotopic organization related to different facial areas.

Endovascular therapy of direct dural carotid cavernous fistulas - A therapy assessment study including long-term follow-up patient interviews.

PURPOSE: Endovascular embolization nowadays is a well-established treatment option for direct carotid cavernous fistulas (dCCF, Barrow Type A). There are many publications on the complication and success rates of this method. However, little is known on the patients´ opinion on the treatment result after several years. We report on this issue also including the "pioneer patients" treated almost two decades ago. METHODS: We retrospectively reviewed the records of all patient (n = 25) with a more than 24 months follow-up interval after endovascular treatment of a dCCF at our institution from 01/1999 to 08/2018. We determined primary therapy success, complication rate, state of the fistula in the last imaging follow-up and quoted the patient's subjective perception of the long-term treatment success using a standardized interview form. RESULTS: Occlusion rate in the last imaging follow up was 96% (24/25) with a complication rate of 8% (2/25). The response rate on our interview request was 96% (24/25) with a rate of considered feedback of 84% (21/25 patients). Duration of our observation interval for the patient reported outcome was 143 months / 11 years (median, range: 35-226 m / 2-18 y). Most of them (21/25, 84%) felt they benefited from the treatment. CONCLUSIONS: Endovascular supply of dCCF is a highly effective treatment method leading to a sustainable therapy success with long-lasting stable subjective benefit even to our "pioneer patients" treated almost two decades ago.

Reduction of olfactory sensitivity during normobaric hypoxia.

OBJECTIVE: Acute mountain sickness (AMS) is caused by a low partial pressure of oxygen and may occur above 2500m. The aim of this research was to evaluate olfactory and gustatory abilities of healthy subjects during baseline conditions and after seven hours of normobaric hypoxia. METHODS: Sixteen healthy subjects were assessed using the Sniffin' Sticks, as well as intensity and pleasantness ratings. Gustatory function was evaluated utilizing the Taste Strips. Experiments were carried out under baseline conditions (518m altitude) followed by a second testing session after seven hours of normobaric hypoxia exposure (comparable to 4000m altitude). RESULTS: During normobaric hypoxia olfactory sensitivity and intensity estimates were significantly reduced. CONCLUSIONS: We conclude that normobaric hypoxia leads to a significant decrease of olfactory sensitivity and intensity ratings.

Endovascular therapy of low- and intermediate-grade intracranial lateral dural arteriovenous fistulas: a detailed analysis of primary success rates, complication rates, and long-term follow-up of different technical approaches.

OBJECTIVE Sinus-preserving (SP) embolization techniques augment endovascular treatment options for intracranial lateral dural arteriovenous fistulas (DAVFs). The authors aimed to perform a retrospective comparison of their primary success rates, complication rates, and long-term follow-up with those of sinus-occluding (SO) treatment variants in the collective of low- and intermediate-grade lateral DAVFs (Cognard Types I-IIb). METHODS Clinical symptoms, complication rates, and Cognard grading prior to and after endovascular DAVF treatment using different technical approaches was retrospectively analyzed in 36 patients with lateral DAVF Cognard Types I-IIb. The long-term success rate was determined by a standardized questionnaire. RESULTS The SO approaches offered a higher rate of definitive fistula occlusion (93% SO vs 71% SP) but were accompanied by a significantly higher complication rate (33% or 20% SO vs 0% SP). The patients interviewed reported very high satisfaction with their health in long-term follow-up in both groups. CONCLUSIONS A higher rate of definitive fistula occlusion in the SO group was attained at the price of a significantly higher complication rate. The SP approaches offered a good primary success rate in combination with a very low complication rate. Despite some limitations of the data (e.g., a small sample size) the authors thus recommend an SP variant as the primary therapeutic option for the endovascular treatment of low- and intermediate-grade DAVFs. The SO approaches should be restricted to cases in which SP treatment does not achieve a downgrading to no worse than Cognard Type IIa.

Intracranial Aneurysms Treated by Flow-Diverting Stents: Long-Term Follow-Up with Contrast-Enhanced Magnetic Resonance Angiography.

PURPOSE: Long-term data on aneurysm treatment with flow-diverting stents are still sparse, and follow-up protocols differ widely between institutions. We present long-term results, with a focus on the usefulness of contrast-enhanced MR angiography (ceMRA). MATERIALS AND METHODS: Interventions and follow-up imaging of patients with aneurysms treated by flow-diverting stents ("Pipeline," "Silk" and "FRED" models) without additional coiling were analyzed. All MRI scans included dedicated two-phase ceMRA. Aneurysm occlusion rates, size of the aneurysmal sac and complications were evaluated on MRI and digital subtraction angiography (DSA), where available. The ability of ceMRA to depict aneurysm occlusion and stent patency was graded on a three-point scale. RESULTS: Twenty-five patients with 102 MRI scans were included. The median duration of follow-up was 830 days. Aneurysm occlusion rates were 52% at 3 months (10 of 19 patients), 72% at 6 months (18/25) and 84% overall (21/25). Shrinkage of the aneurysmal sac was found in 19 patients (76%) and in 12 cases to <50% of the original size (48%). CeMRA assessability of aneurysmal occlusion was graded as good in all cases. When compared to DSA (18 cases), ceMRA had a sensitivity of 100% and specificity of 91% regarding aneurysm remnant detection. Assessability of the stent lumen varied and was limited in most cases. CONCLUSIONS: Flow-diverter treatment achieves high occlusion rates and can cause major aneurysm shrinkage. CeMRA is highly valuable regarding imaging of the aneurysmal sac. There are limitations regarding the assessability of the stent lumen on ceMRA. LEVEL OF EVIDENCE: Level 4, Case Series.

Endovascular stroke treatment now and then-procedural and clinical effectiveness and safety of different mechanical thrombectomy techniques over time.

BACKGROUND: The most essential development in endovascular stroke treatment (EST) was the shift from intra-arterial thrombolysis to endovascular thrombectomy with dedicated thrombectomy devices, most notably the introduction of stent-retrievers. We evaluated procedural and clinical effectiveness and safety of different EST techniques over time. METHODS: We retrospectively analyzed EST cases that were treated by the same interventionalist before (n=36) and after (n=50) stent-retrievers were established as the treatment device of first choice. EST techniques in the first cohort comprised intra-arterial thrombolysis (n=24), manual thrombus aspiration (n=15), the use of the Penumbra thrombectomy system (n=13) and the Phenox clot retriever (n=3), intracranial stenting (n=10), and EST with stent-retrievers as a salvage procedure (n=11). In the second cohort, EST with stent-retrievers was the treatment option of first choice (n=47). Intra-arterial thrombolysis (n=15) and stenting of the occluded vessel (n=1) were performed, whenever EST with stent-retrievers failed. RESULTS: In both cohorts, revascularization rates (TICI ≥2b) were high (91.7% and 86.0%, respectively). A significantly lower number of interventional techniques per case were required in the second cohort (mean ± SD, 1.4±0.5 vs. 2.1±0.9, P<0.001). Recanalization was achieved almost twice as fast in the second cohort (85 vs. 163 minutes on average, P<0.001). The rate of patients achieving good functional outcome (mRS ≤2) was higher in the second cohort (40.0% vs. 22.2%, P=0.083). CONCLUSIONS: Our findings imply that when stent-retrievers were established as first-line the treatment device a significantly lower number of interventional techniques per case were required and recanalization was achieved almost twice as fast.

Long-term Neurological Outcome and Quality of Life after World Federation of Neurosurgical Societies Grades IV and V Aneurysmal Subarachnoid Hemorrhage in an Interdisciplinary Treatment Concept.

BACKGROUND: Detailed data on long-term functional outcome of patients with World Federation of Neurosurgical Societies (WFNS) grades IV and V aneurysmal subarachnoid hemorrhages (aSAH) are still scarce. OBJECTIVE: Assessment of long-term outcome of WFNS IV and V aSAH patients. METHODS: Functional outcome and quality of life were assessed by the modified Rankin scale (mRS) and the 36-item short-form health survey in consecutively treated aSAH WFNS IV and V patients between 2005 and 2010. Scores from the 36-item short-form health survey were compared to a healthy German population. Prognostic factors were analyzed by uni- and multivariate models. RESULTS: One hundred and seven eligible patients (median age: 53.0 years) were identified. After interdisciplinary consensus on optimal treatment, aneurysms were obliterated either by clipping (n = 35) or by coiling (n = 72). Ten patients were lost to long-term follow-up; the median clinical follow-up period was 3.2 years for the remaining 97 cases. Twenty-five of 97 died during the acute hospital phase and another 10 patients over the follow-up period leaving 62 long-term survivors. At the end of clinical follow-up, 40/97 patients, including 40/62 of long-term survivors, reached functional independence (mRS ≤ 2). Twelve of 97 patients were moderately (mRS = 3), 10/97 patients were severely disabled (mRS ≥ 4). Younger age (≤ 53 years; P = .001) and radiological absence of cerebral infarction ( P = .03) were the strongest predictors for favorable outcome. Quality of life was perceived to be only moderately reduced compared to the healthy control group. CONCLUSION: Poor-grade aSAH is not necessarily associated with poor long-term functional outcome; after aneurysm repair ∼60% of patients survived and among long-term survivors ∼ 60% regained functional independence.

Reproducibility of activation in four motor paradigms. An fMRI study.

Most functional imaging data are collected in single session experiments; little is known about the reproducibility or test-retest reliability of the activation patterns found in these experiments. In our study, 15 healthy volunteers performed four simple motor-paradigms ("Hand", "Foot", "Mouth" and "Tongue") for functional magnetic resonance imaging (fMRI) in 3 sessions on different days. Reproducibility of activations in four anatomical regions (pre- and postcentral gyri, paracentral lobule and the supplementary motor area) was measured in terms of voxels active in all sessions (common voxels) relative to voxels active in single sessions, giving reliability coefficients from 0 to 1. Two significance levels were used to identify active voxels. Reproducibility of activations was highest for foot and hand movements in the primary motorsensory areas; reliability coefficients were in the range of 0.62 to 0.78. Activations for mouth movements showed a very poor reproducibility. Application of the more stringent statistical threshold always led to a reduction of reproducible voxels. Reliability of fMRI data is not only a theoretical issue, but is of special practical importance in clinical settings such as integration of fMRI into neuronavigation for neurosurgical planning. Much care has to be taken if only single session data are available for interpretation.

Early treatment of complex located pediatric low-grade gliomas using iodine-125 brachytherapy alone or in combination with microsurgery.

To analyze efficacy, functional outcome, and treatment toxicity of low-dose rate I-125 brachytherapy (SBT) alone or in combination with best safe resection (in case of larger tumor volumes) as first-line treatment for pediatric low-grade gliomas (PLGGs) not suitable for complete resection. Consecutively treated (2000-2014) complex located circumscribed WHO grade I/II PLGGs were included. For small tumors (≤4 cm in diameter) SBT alone was performed; for larger tumors best safe resection and subsequent SBT was chosen. Temporary Iodine-125 seeds were used (median reference dose: 54 Gy). Treatment response was estimated with the modified MacDonald criteria. Analysis of functional outcome included ophthalmological, endocrinological and neurological evaluation. Survival was analyzed with the Kaplan-Meier method. Prognostic factors were obtained from proportional hazards models. Toxicity was categorized according to the Common Terminology Criteria for Adverse Events. Fifty-eight patients were included treated either with SBT alone (n = 39) or with SBT plus microsurgery (n = 19). Five-year progression-free survival was 87%. Two patients had died due to tumor progression. Among survivors, improvement/stabilization/deterioration of functional deficits was seen in 20/14/5 patients, respectively. Complete/partial response had beneficial impact on functional scores (P = 0.02). The 5-year estimated risk to receive adjuvant radiotherapy/chemotherapy was 5.2%. The overall early (delayed) toxicity rate was 8.6% (10.3%), respectively. No permanent morbidity occurred. In complex located PLGGs, early SBT alone or combined with best safe resection preserves/improves functional scores and results in tumor control rates usually achieved with complete resection. Long-term analysis is necessary for confirmation of these results.

Susceptibility-weighted angiography visualizes hypoxia in cerebral veins.

OBJECTIVES: The objective of this study was to evaluate the influence of short- and long-term hypoxia on the depiction of cerebral veins in the susceptibility-weighted angiography (SWAN) sequence. MATERIALS AND METHODS: In the context of a study on brain adaptation mechanisms to hypoxia, 16 healthy men (aged 20-28 years) were studied through magnetic resonance imaging (MRI) under room air conditions, short-term-hypoxia (7 minutes before and during the MRI scan), and long-term hypoxia (8.5 hours before and during the MRI scan). Oxygen saturation was continuously measured using a finger-mounted pulse oximeter. Two independent blinded readers compared the 3 scans of each participant and graded the SWAN source images and minimum intensity projections according to the size, number, and signal intensity of the cerebral veins. Signal intensities of deep cerebral veins were measured, and signal intensity proportions of deep cerebral veins to different parenchymal brain regions were calculated. RESULTS: Nine subjects could be included in the study. In all of them, both readers correctly distinguished the 2 hypoxia scans from the baseline scan, grading the SWAN images acquired under hypoxic conditions as visualizing cerebral veins more prominently. Signal intensities of the deep cerebral veins and signal intensity proportions were significantly lower in the hypoxia scans. No significant differences between short-term and long-term hypoxia were found on visual inspections and signal intensity measurements. This correlated with the results of the pulse oximetry: mean O2 saturation values were 97.9% ± 1.2% (baseline), 84.1% ± 3.8% (short-term hypoxia), and 82.8% ± 4.4% (long-term hypoxia), respectively. CONCLUSIONS: Hypoxia leads to visible and measurable changes in cerebral veins as depicted through SWAN. Possible clinical implications of this finding include stroke and tumor imaging and need further investigation.

Detailed anatomy of the intracranial segment of the hypoglossal nerve: neurovascular relationships and landmarks on magnetic resonance imaging sequences.

OBJECT: The thin hypoglossal nerve can be very difficult to distinguish on magnetic resonance (MR) images. The authors used a combination of sequences to increase the reliability of MR imaging in its demonstration of the 12th cranial nerve as well as to assess the course of the nerve, display its relationships to adjacent vessels, and provide landmarks for evaluating the nerve in daily practice. METHODS: The study group consisted of 34 volunteers (68 nerves) in whom a three-dimensional (3D) Fourier-transformation constructive interference in steady-state (CISS) sequence and a 3D T1-weighted contrast-enhanced magnetization-prepared rapid-acquisition gradient-echo (MPRAGE) sequence were applied. Two trained neuroradiologists collaboratively identified the hypoglossal trigone, preolivary sulcus, 12th cranial nerve, posterior inferior cerebellar artery, vertebral artery, 12th nerve root sleeve, and the hypoglossal canal on each side. The 3D CISS sequence successfully demonstrated the hypoglossal trigone (100% of images), 12th nerve root bundles (100% of images), and 12th nerve sleeves (88.2% of images). The canalicular segment was exhibited with the aid of plain 3D CISS sequences in 74% of images and by using contrast-enhanced 3D CISS sequences and contrast-enhanced MPRAGE sequences in 100% of images. The landmarks that proved useful to identify the cisternal segment of the 12th cranial nerve included the hypoglossal trigone, preolivary sulcus, and 12th nerve root sleeve. Neurovascular contact was identified in 61% of root bundles. The roots were distorted in 44% of these contacts. CONCLUSIONS: The contrast-enhanced 3D CISS sequence consistently displayed the cisternal segment as well as the canalicular segments of the hypoglossal nerve and is, therefore, the best sequence to visualize the complete cranial course of this nerve. Landmarks such as the 12th nerve sleeves can assist in the identification of this nerve.