Endovascular treatment of basilar tip aneurysms in the era of endosaccular flow disruption: a comparative study.

PURPOSE: This study aims to compare endosaccular flow disruptor (EFD) for treatment of basilar tip aneurysm (BTA) with coiling in terms of safety and efficacy. METHODS: We retrospectively reviewed patients treated with an EFD for BTAs at our institution between 2013 and 2019 to standard coiling from the same period (control group). Patient demographics, aneurysm characteristics, procedural data, complications and clinical and angiographic outcome were compared between groups. RESULTS: Twenty-three (56%) patients were treated with an EFD and eighteen (44%) patients were treated with coiling. Average aneurysm size was 8 mm in the EFD group and 6.9 mm in the coiling group, respectively (P = 0.2). Average fluoroscopy time, treatment DAP and air kerma were 33 min, 76 Gycm2 and 1.7 Gy in the EFD group and 81 min, 152 Gycm2 and 3.8 Gy in the coiling group, respectively (P < 0.001). In the EFD group, clinically relevant thromboembolic complications occurred in one patient (4%) vs. in 5 patients (28%) in the coiling group (P = 0.07). In each group, 4 patients had an unfavourable outcome at discharge (P = 0.7). Adequate occlusion rates were 96% in the EFD group and 100% and coiling group. Six (26%) patients were prescribed long-term antiplatelet therapy in the EFD group vs. eleven (61%) patients in the coiling group (P = 0.02). CONCLUSION: Both treatment concepts provided similar technical success and safety. However, procedure time, radiation exposure and a need for long-term antiaggregation were lower with EFD.

Contralateral Stenosis and Echolucent Plaque Morphology are Associated with Elevated Stroke Risk in Patients Treated with Asymptomatic Carotid Artery Stenosis within a Controlled Clinical Trial (SPACE-2).

BACKGROUND: Asymptomatic carotid artery stenosis (ACS) has a low risk of stroke. To achieve an advantage over noninterventional best medical treatment (BMT), carotid endarterectomy (CEA) or carotid artery stenting (CAS) must be performed with the lowest possible risk of stroke. Therefore, an analysis of risk-elevating factors is essential. Grade of ipsilateral and contralateral stenosis as well as plaque morphology are known risk factors in ACS. METHODS: The randomized, controlled, multicenter SPACE-2 trial had to be stopped prematurely after recruiting 513 patients. 203 patients were randomized to CEA, 197 to CAS, and 113 to BMT. Within one year, risk factors such as grade of stenosis and plaque morphology were analyzed. RESULTS: Grade of contralateral stenosis (GCS) was higher in patients with any stroke (50%ECST vs. 20%ECST; p=0.012). Echolucent plaque morphology was associated with any stroke on the day of intervention (OR 5.23; p=0.041). In the periprocedural period, any stroke was correlated with GCS in the CEA group (70%ECST vs. 20%ECST; p=0.026) and with echolucent plaque morphology in the CAS group (6% vs. 1%; p=0.048). In multivariate analysis, occlusion of the contralateral carotid artery (CCO) was associated with risk of any stroke (OR 7.00; p=0.006), without heterogeneity between CEA and CAS. CONCLUSION: In patients with asymptomatic carotid artery stenosis, GCS, CCO, as well as echolucent plaque morphology were associated with a higher risk of cerebrovascular events. The risk of stroke in the periprocedural period was increased by GCS in CEA and by echolucent plaque in CAS. Due to small sample size, results must be interpreted carefully.

Standards of practice in interventional neuroradiology.

The growing importance of INR has resulted in the need to define and promote professional standards of clinical practice. Several professional organizations have published guidelines recently for the neurointerventional treatment of cerebrovascular diseases, including technical and personal recommendations, but detailed definitions of technical and organizational conditions needed for the safe and effective performance of such treatments are lacking. To fill this gap ESNR, ESMINT and the UEMS Division for Neuroradiology established a working group, to develop a consensus paper on "Standards of Practice in Interventional Neuroradiology". This document is the result of the Consensus Working Group and has following review gained approval by the Executive Boards of ESNR and ESMINT and by the members of the UEMS Division for Neuroradiology in 2017.

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.

Visualization of Liliequist's membrane prior to endoscopic third ventriculostomy.

PURPOSE: Endoscopic third ventriculostomy (ETV) is an effective treatment in patients with obstructive hydrocephalus caused by aqueductal stenosis. Operative failure may occur if an unnoticed membrane below the floor of the third ventricle is present, such as Liliequist's membrane (LM). To analyze how often LM can be visualized by high-resolution heavily T2-weighted 3D-MRI prior to ETV, and to find out potential reasons for diagnostic failure. MATERIALS AND METHODS: Preoperative 3D-MR images of 37 consecutive patients (19 female, median 42 years) were retrospectively analyzed. Visualization of three LM segments (sellar, diencephalic, mesencephalic), dimensions of the space below the third ventricle, and extent of hydrocephalus were measured. Image quality was scored (score 1[poor] to 3[excellent]). Preoperative imaging findings were compared with intraoperative findings. RESULTS: Patients were subdivided into group 1 (no segment of LM identified, n = 18), and group 2 (at least one segment of LM was identified, n = 19). The sellar segment of LM was most often positively identified (10 out of 19 cases). The mean distance between the pons and the sella/clivus was significantly shorter in group 1 than in group 2 (3.7 vs. 6.2 mm; p < 0.01). Other variables, such as the distance between tip of the pons and the mamillary bodies as well as the image quality, were not significantly different between both groups. Intraoperatively, LM was present in 78 % of group 2 patients, and in 28 % of group 1 patients, respectively (p < 0.03). CONCLUSIONS: LM can be detected in about half of patients prior to ETV. Reduced PSD influences visualization of LM.

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.

The value of magnetic resonance imaging for the detection of the bleeding source in non-traumatic intracerebral haemorrhages: a comparison with conventional digital subtraction angiography.

INTRODUCTION: Conventional digital subtraction angiography (DSA) is currently regarded as the gold standard in detecting underlying vascular pathologies in patients with intracerebral haemorrhages (ICH). However, the use of magnetic resonance imaging (MRI) in the diagnostic workup of ICHs has considerably increased in recent years. Our aim was to evaluate the diagnostic accuracy and yield of MRI for the detection of the underlying aetiology in ICH patients. METHODS: Sixty-seven consecutive patients with an acute ICH who underwent MRI (including magnetic resonance angiography (MRA) and DSA during their diagnostic workup) were included in the study. Magnetic resonance images were retrospectively analysed by two independent neuroradiologists to determine the localisation and cause of the ICH. DSA was used as a reference standard. RESULTS: In seven patients (10.4%), a DSA-positive vascular aetiology was present (one aneurysm, four arteriovenous malformations, one dural arteriovenous fistula and one vasculitis). All of these cases were correctly diagnosed by both readers on MRI. In addition, MRI revealed the following probable bleeding causes in 39 of the 60 DSA-negative patients: cerebral amyloid angiopathy (17), cavernoma (9), arterial hypertension (8), haemorrhagic transformation of an ischaemic infarction (3) and malignant brain tumour with secondary ICH (2). CONCLUSION: Performing MRI with MRA proved to be an accurate diagnostic tool in detecting vascular malformations in patients with ICH. In addition, MRI provided valuable information regarding DSA-negative ICH causes, and thus had a high diagnostic yield in ICH patients.

New similarity search based glioma grading.

INTRODUCTION: MR-based differentiation between low- and high-grade gliomas is predominately based on contrast-enhanced T1-weighted images (CE-T1w). However, functional MR sequences as perfusion- and diffusion-weighted sequences can provide additional information on tumor grade. Here, we tested the potential of a recently developed similarity search based method that integrates information of CE-T1w and perfusion maps for non-invasive MR-based glioma grading. METHODS: We prospectively included 37 untreated glioma patients (23 grade I/II, 14 grade III gliomas), in whom 3T MRI with FLAIR, pre- and post-contrast T1-weighted, and perfusion sequences was performed. Cerebral blood volume, cerebral blood flow, and mean transit time maps as well as CE-T1w images were used as input for the similarity search. Data sets were preprocessed and converted to four-dimensional Gaussian Mixture Models that considered correlations between the different MR sequences. For each patient, a so-called tumor feature vector (= probability-based classifier) was defined and used for grading. Biopsy was used as gold standard, and similarity based grading was compared to grading solely based on CE-T1w. RESULTS: Accuracy, sensitivity, and specificity of pure CE-T1w based glioma grading were 64.9%, 78.6%, and 56.5%, respectively. Similarity search based tumor grading allowed differentiation between low-grade (I or II) and high-grade (III) gliomas with an accuracy, sensitivity, and specificity of 83.8%, 78.6%, and 87.0%. CONCLUSION: Our findings indicate that integration of perfusion parameters and CE-T1w information in a semi-automatic similarity search based analysis improves the potential of MR-based glioma grading compared to CE-T1w data alone.

Trigeminal neuralgia due to neurovascular compression: high-spatial-resolution diffusion-tensor imaging reveals microstructural neural changes.

PURPOSE: To preoperatively detect, by using diffusion-tensor imaging coregistered with anatomic magnetic resonance (MR) imaging, suspected microstructural tissue changes of the trigeminal nerves in patients with trigeminal neuralgia (TN) resulting from neurovascular compression. MATERIALS AND METHODS: The study was approved by the institutional review board, and written informed consent was obtained from all patients. Twenty patients (mean age, 51.3 years) with TN and evidence of neurovascular contact were examined with use of a 3.0-T MR unit combined with an eight-channel head coil before undergoing surgical decompression. A single-shot diffusion-tensor echo-planar sequence was used along 15 different diffusion directions, with a b value of 1000 sec/mm(2) and a section thickness of 2 mm. For anatomic correlation, 0.6-mm isotropic three-dimensional fast imaging employing steady-state images were acquired for coregistration with the functional diffusion-tensor maps. After region of interest placement, mean fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were calculated for each nerve by using the paired-sample two-tailed t test (with P < .005 indicating significance) and compared with surgical findings. RESULTS: FA was significantly lower (P = .004) on the trigeminal neuralgia-affected side (mean FA, 0.203) than on the contralateral side (mean FA, 0.239). ADCs were nearly identical between the normal and TN-affected nerve tissues. CONCLUSION: These findings suggest that diffusion-tensor imaging enables the identification and quantification of anisotropic changes between normal nerve tissue and TN-affected trigeminal nerves. Coregistration of anatomic three-dimensional fast imaging employing steady-state imaging and diffusion-tensor imaging facilitates excellent delineation of the cisternal segments of the trigeminal nerves.

Smelling chemosensory signals of males in anxious versus nonanxious condition increases state anxiety of female subjects.

The hypothesis of this experiment was that humans in an anxious state compared with a nonanxious state are able to increase anxiety levels in other humans via their body odors. Specifically, we hypothesized that male chemosensory anxiety signals compared with neutral chemosignals increase state anxiety of female subjects. Thirteen male subjects participated in 2 different sweat donation sessions: chemosignals were collected during participation in a high rope course (anxiety condition) and in an ergometer workout (neutral condition). State and trait anxiety were evaluated in 20 female odor recipients using Spielberger's state-trait anxiety inventory in a double-blind design. Comparison of state anxiety of odor donors between control and anxiety condition differed significantly indicating that our model of anxiety induction successfully led to the expected change in emotion. Comparison of state anxiety of odor recipients showed a trend toward higher state anxiety in the anxiety condition compared with the neutral condition after 5 min of odor exposure. After 20 min of odor exposure, state anxiety of female subjects was significantly higher during the perception of sweat collected during the anxiety condition in comparison with the perception of sweat collected during the neutral condition. This experiment gives evidence that male anxiety chemosignals compared with neutral chemosignals are capable of inducing an increased state anxiety in female subjects.

Presence of a central vein within white matter lesions on susceptibility weighted imaging: a specific finding for multiple sclerosis?

INTRODUCTION: Susceptibility weighted imaging depicts the perivenous extent of multiple sclerosis white matter lesions (MS-WML) in vivo by directly visualizing their centrally running vein. The aim of this study was to investigate the specificity of this finding for MS. METHODS: Fifteen patients with MS and 15 patients with microangiopathic white matter lesions (mWML) underwent 3T MRI, including a fluid-attenuated inversion recovery sequence (FLAIR) and a susceptibility weighted angiography (SWAN). All WMLs were identified on FLAIR and assigned to one of the following localizations: supratentorial peripheral, supratentorial periventricular, or infratentorial. Subsequently, the presence of a central vein within these lesions was assessed on SWAN. RESULTS: A total of 711 MS-WMLs and 1,119 m-WMLs were identified on FLAIR, all of which could also be visualized on SWAN. A central vein was detectable in 80% of the MS-WMLs and in 78% of the m-WMLs (in 73% and 76% of the peripheral, in 92% and 94% of the periventricular, and in 71% and 75% of the infratentorial MS-WMLs and m-WMLs, respectively). With regard to the supratentorial peripheral lesions, significantly more m-WMLs showed a central vein compared to the MS-WMLs. For the other localizations, there was no significant difference between the groups with regard to the percentage of lesions with central vein. CONCLUSIONS: Our results indicate that the detection of a central vein within a WML should not be considered a specific finding for MS; it is also found in WMLs of other etiologies.

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.

Orbitofrontal volume reductions during emotion recognition in patients with major depression.

BACKGROUND: Major depressive disorder is associated with both structural and functional alterations in the emotion regulation network of the central nervous system. The relation between structural and functional changes is largely unknown. Therefore, we sought to determine the relation between structural differences and functional alterations during the recognition of emotional facial expressions. METHODS: We examined 13 medication-free patients with major depression and 15 healthy controls by use of structural T1-weighted high-resolution magnetic resonance imaging (MRI) and functional MRI during 1 session. We set the statistical threshold for the analysis of imaging data to p < 0.001 (uncorrected). RESULTS: As shown by voxel-based morphometry, depressed patients had reductions in orbitofrontal cortex volume and increases in cerebellar volume. Additionally, depressed patients showed increased activity during emotion recognition in the middle frontal cortex, caudate nucleus, precuneus and lingual gyrus. Within this cerebral network, the orbitofrontal volumes were negatively correlated in depressed patients but not in healthy controls with changes in blood oxygen level-dependent signal in the middle frontal gyrus, caudate nucleus, precuneus and supplementary motor area. LIMITATIONS: Our results are limited by the relatively small sample size. CONCLUSIONS: This combined functional and structural MRI study provides evidence that the orbitofrontal cortex is a key area in major depression and that structural changes result in functional alterations within the emotional circuit. Whether these alterations in the orbitofrontal cortex are also related to persistent emotional dysfunction in remitted mental states and, therefore, are related to the risk of depression needs further exploration.

Cortical vein thrombosis: the diagnostic value of different imaging modalities.

INTRODUCTION: Cortical vein thrombosis (CVT) is a rare disorder, and its diagnosis is challenging. The aim of our study was to evaluate the value of different imaging modalities for the detection of CVT. METHODS: Thirteen patients with CVT, either isolated (n = 3) or in combination with sinus thrombosis (n = 10), and 20 control patients without any venous pathologies were included in this study. The analysis was performed independently by three blinded readers who evaluated the following imaging modalities and sequences separately: non-enhanced computed tomography (NCCT); multi-detector row CT angiography (MDCTA); diffusion-weighted (DWI), T1-weighted (T1w), PD-weighted (PDw), T2*-weighted (T2*w), and fluid-attenuated inversion recovery-weighted (FLAIRw) magnetic resonance (MR) sequences; as well as venous MR angiography (vMRA). The sensitivity, specificity, positive (PPV) and negative predictive values, and interobserver agreement of the different modalities were calculated. RESULTS: T2*w showed the highest sensitivity for the detection of CVT (97.4%), followed by T1w (70%). FLAIRw and vMRA had a sensitivity of 50% and 41.7%, respectively, whereas the sensitivity of NCCT, MDCTA, DWI, and PDw was below 30%. The specificity and PPV of all modalities was 100%, with good to perfect interobserver agreement. CONCLUSION: T2*w was the superior MR imaging sequence for diagnosing CVT. Besides T2*w, only T1w reached a sensitivity of over 50% for CVT, followed by FLAIRw, and vMRA. On the contrary, our results suggest that NCCT but also MDCTA might not be suitable for diagnosing CVT.

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.

Protection or nonprotection in carotid stent angioplasty: the influence of interventional techniques on outcome data from the SPACE Trial.

BACKGROUND AND PURPOSE: The use of protection devices (PDs) and stents with different cell designs in carotid artery stenting (CAS) is a subject of controversy, and no data on their benefit are available from independently controlled multi-center studies. METHODS: We analyzed data from the prospective randomized SPACE trial, which included 563 patients randomized to CAS and treated per protocol. A total of 145 patients were treated with a PD and 418 without. Of the patients, 436 were treated with an open cell stent and 127 with a closed cell stent. Use of PDs and choice of device was chosen at the individual discretion of the interventionalist. RESULTS: The outcome event (OE) of the analysis (ipsilateral stroke or ipsilateral stroke death within 30 days) was reached in 26/418 patients (6.2%, 95% CI: 4.1 to 9.0%) in the nonprotection [corrected] group and in 12/145 (8.3%, 95% CI: 4.3 to 14.0%) patients in the protection [corrected] group (P=0.40). The OE rate was significantly lower in patients treated with a closed cell stent (5.6% [95% CI: 3.7 to 8.2%]) than in those treated with an open cell stent.(11.0%, 95% CI: 6.2 to 17.8%; P=0.029). Predilatation showed a tendency to but no significant reduction of OE rate. Overall, 49% of all OEs occurred directly periinterventionally, 10% during the navigation procedure and 41% postinterventionally, including 10% of hyperperfusion syndromes. Time point of the event was not influenced by the use of a PD. CONCLUSIONS: This secondary analysis of data from the SPACE trial does not support the need for a PD in CAS. Stent design seems to have an impact on the OE rate. Our analysis demonstrates that the choice of the interventional material may have an impact on the periprocedural complication rate in CAS and that the development of more specific stent systems for the treatment of carotid stenosis may reduce the complication rate significantly.

Activation of olfactory and trigeminal cortical areas following stimulation of the nasal mucosa with low concentrations of S(-)-nicotine vapor--an fMRI study on chemosensory perception.

Applied to the nasal mucosa in low concentrations, nicotine vapor evokes odorous sensations (mediated by the olfactory system) whereas at higher concentrations nicotine vapor additionally produces burning and stinging sensations in the nose (mediated by the trigeminal system). The objective of this study was to determine whether intranasal stimulation with suprathreshold concentrations of S(-)-nicotine vapor causes brain activation in olfactory cortical areas or if trigeminal cortical areas are also activated. Individual olfactory detection thresholds for S(-)-nicotine were determined in 19 healthy occasional smokers using a computer-controlled air-dilution olfactometer. Functional magnetic resonance images were acquired using a 1.5T MR scanner with applications of nicotine in concentrations at or just above the individual's olfactory detection threshold. Subjects reliably perceived the stimuli as being odorous. Accordingly, activation of brain areas known to be involved in processing of olfactory stimuli was identified. Although most of the subjects never or only rarely observed a burning or painful sensation in the nose, brain areas associated with the processing of painful stimuli were activated in all subjects. This indicates that the olfactory and trigeminal systems are activated during perception of nicotine and it is not possible to completely separate olfactory from trigeminal effects by lowering the concentration of the applied nicotine. In conclusion, even at low concentrations that do not consistently lead to painful sensations, intranasally applied nicotine activates both the olfactory and the trigeminal system.

Cisternal segments of the glossopharyngeal, vagus, and accessory nerves: detailed magnetic resonance imaging-demonstrated anatomy and neurovascular relationships.

OBJECT: The aim of this study was to determine whether high-resolution MR imaging is suitable for identifying and differentiating among the nerve root bundles of the glossopharyngeal (cranial nerve [CN] IX), vagus (CN X), and accessory nerves (CN XI) as well as any adjacent vessels. METHODS: Twenty-five patients (50 sides) underwent MR imaging using the 3D constructive interference in steady-state (CISS) sequence, as well as noncontrast and contrast-enhanced 3D time-of-flight (TOF) MR angiography. Two individuals scored these studies by consensus to determine how well these sequences displayed the neurovascular contacts and nerve root bundles of CNs IX and X and the cranial and spinal roots of CN XI. Landmarks useful for identifying each lower CN were specifically sought. RESULTS: The 3D CISS sequence successfully depicted CNs IX and X in 100% of the sides. Nerve root bundles of the cranial segment of CN XI were identified in 88% of the sides and those of the spinal segment of CN XI were noted in 93% of the sides. Landmarks useful in identifying the lower CNs included the vagal trigone, the choroid plexus of the lateral recess, the glossopharyngeal and vagal meatus, the inferior petrosal sinus, and the vertebral artery. The combined use of 3D CISS and 3D TOF sequences demonstrated neurovascular contacts at the nerve root entry or exit zones in 19% of all nerves visualized. CONCLUSIONS: The combined use of 3D CISS MR imaging and 3D TOF MR angiography (with or without contrast) successfully displays the detailed anatomy of the lower CNs and adjacent structures in vivo. These imaging sequences have the potential to aid the preoperative diagnosis of and the presurgical planning for pathology in this anatomical area.

Differential diagnosis of nontraumatic intracerebral hemorrhage.

A wide variety of nontraumatic pathologies can result in intracerebral hemorrhage (ICH). Primary causes such as arterial hypertension or cerebral amyloid angiopathy can be differentiated from secondary pathologies, such as neoplasms, arterio-venous malformations, coagulopathies, hemorrhagic ischemic strokes, and cerebral venous and sinus thrombosis.Here, the authors first provide some general information on epidemiology, clinical presentation, and imaging appearance of ICHs followed by a detailed discussion of the different underlying pathologic entities and their imaging presentation.

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.