Troponin I as an Early Biomarker of Cardiopulmonary Parameters Within the First 24 Hours After Nontraumatic Subarachnoid Hemorrhage in Intensive Care Unit Patients.

OBJECTIVE: The elevation of serum cardiac troponin I (TNI) in patients with nontraumatic subarachnoid hemorrhage (ntSAH) is a well-known phenomenon. However, the relation between elevated TNI and different cardiopulmonary parameters (CPs) within the first 24 hours after ntSAH is unknown. The present study was conducted to investigate the association between TNI and different CP in patients with ntSAH within the first 24 hours of intensive care unit (ICU) treatment. PATIENTS AND METHODS: We retrospectively analyzed a consecutive group of 117 patients with ntSAH admitted to our emergency department between January 2008 and February 2017. Blood samples were taken to determine TNI values on admission. Demographic data, baseline Glasgow Coma Scale (GCS) score, World Federation of Neurosurgical Societies (WFNS) score, baseline Fisher grade (FG), norepinephrine application rate (NAR) in µg/kg/min, and inspiratory oxygen fraction (OF) were recorded within the first 24 hours. RESULTS: An increased TNI value was found in 32 (27.4%) of 117 patients. There was a significant correlation between initial elevated TNI and a low WFNS score (P = .007), a low GCS score (P = .003) as well as a high OF (P = <.001). The FG (P = .27) and NAR (P = .08) within the first 24 hours of ICU treatment did not show any significant correlation. CONCLUSIONS: In the present study, an increased TNI value was significantly associated with a low WFNS score and GCS score on admission. The TNI was a predictor of the need for a higher OF within the first 24 hours after ntSAH so that TNI could be an informative biomarker to improve ICU therapy.

Technical accuracy of the integration of an external ultrasonography system into a navigation platform: effects of ultrasonography probe registration and target detection.

BACKGROUND: Intraoperative navigated ultrasonography has reached clinical acceptance, while published data for the accuracy of some systems are missing. We technically quantified and optimised the accuracy of the integration of an external ultrasonography system into a BrainLab navigation system. METHODS: A high-end ultrasonography system (Elegra; Siemens, Erlangen, Germany) was linked to a navigation system (Vector Vision; BrainLab, Munich, Germany). In vitro accuracy and precision was calculated from differences between a real world target (high-precision crosshair phantom) and the ultrasonography image of this target in the navigation coordinate system. The influence of the intrinsic component of the calibration phantom (for ultrasonography probe registration), type of target definition (manual versus automatic) and orientation of the ultrasound probe in relation to the navigation tracking device on accuracy and precision were analysed in different settings (100 measurements for each setting) resembling clinically relevant scenarios in the neurosurgical operating theatre. RESULTS: Line-of-sight angles of 45°, 62° and 90° for the optical tracking of the navigated ultrasonography probe and a distance of 1.8 m revealed best accuracy and precision. Technical accuracy of the integration of ultrasonography into a standard navigation system is high [Euclidean error: median, 0.79 mm; mean, 0.89 ± 0.42 mm for 62° angle; median range: 1.16-1.46 mm; mean range (±SD): 1.22 ± 0.32 mm to 1.46 ± 0.55 mm for grouped analysis of all angles tested]. Software-based automatic target definition improved precision significantly (p < 0.001). CONCLUSIONS: Integration of an external ultrasonography system into the BrainLab navigation is accurate and precise. By modifying registration (and measurement conditions) via software modification, the in vitro accuracy and precision is improved and requirements for a clinical application are fully met.

Treated Versus Untreated Positional Head Deformity.

BACKGROUND: Positional head deformity in early childhood is asserted to be a benign and in some cases spontaneously correcting entity encountered in craniofacial surgery. Although many authors have stated that helmet therapy is indicated in moderate and severe cases of deformational plagiocephaly and brachycephaly; others have reported resolution of these conditions within the first 2 to 3 years of life. A recent randomized controlled trial found that helmet therapy does not have beneficial effects for patients with positional head deformity. METHODS: The authors evaluated the clinical course of positional cranial deformation during a period of 5 years and compared the anthropometric parameters of orthotically treated versus untreated children within this timeframe. RESULTS: Although the patients were matched with respect to their cranial deformation at baseline, there were significant differences in the cranial vault asymmetry (CVA), cranial vault asymmetry index (CVAI), and oblique cranial length ratio (OCLR) between Groups 1 and 2 at the initial point (P < 0.05). The mean CVA was 0.95 cm in Group 1 (no helmet) and 1.74 cm in Group 2 (helmet). The mean CVAI at baseline was 7.25 for Group 1 and 13.77 for Group 2. Approximately 5 years after the first examination, the authors found clear improvement in the mean CVA in Group 2 (ΔCVA 1.35 cm) compared with Group 1 (ΔCVA 0.01 cm) and the mean CVAI. CONCLUSIONS: In contrast to recently published studies, the authors found clear improvement in nonsynostotic head deformity treated with an individual molding helmet and no clear evidence of improvement of absolute measurements in untreated cranial deformity within a 5-year follow-up period.

Accuracy and precision of calibrated arterial pulse contour analysis in patients with subarachnoid hemorrhage requiring high-dose vasopressor therapy: a prospective observational clinical trial.

INTRODUCTION: Calibrated arterial pulse contour analysis has become an established method for the continuous monitoring of cardiac output (PCCO). However, data on its validity in hemodynamically instable patients beyond the setting of cardiac surgery are scarce. We performed the present study to assess the validity and precision of PCCO-measurements using the PiCCO™-device compared to transpulmonary thermodilution derived cardiac output (TPCO) as the reference technique in neurosurgical patients requiring high-dose vasopressor-therapy. METHODS: A total of 20 patients (16 females and 4 males) were included in this prospective observational clinical trial. All of them suffered from subarachnoid hemorrhage (Hunt&Hess grade I-V) due to rupture of a cerebral arterial aneurysm and underwent high-dose vasopressor therapy for the prevention/treatment of delayed cerebral ischemia (DCI). Simultaneous CO measurements by bolus TPCO and PCCO were obtained at baseline as well as 2 h, 6 h, 12 h, 24 h, 48 h and 72 h after inclusion. RESULTS: PCCO- and TPCO-measurements were obtained at baseline as well as 2 h, 6 h, 12 h, 24 h, 48 h and 72 h after inclusion. Patients received vasoactive support with (mean ± standard deviation, SD) 0.57 ± 0.49 µg · kg-1 · min-1 norepinephrine resulting in a mean arterial pressure of 103 ± 13 mmHg and a systemic vascular resistance of 943 ± 248 dyn · s · cm-5. 136 CO-data pairs were analyzed. TPCO ranged from 5.2 to 14.3 l · min-1 (mean ± SD 8.5 ± 2.0 l · min-1) and PCCO ranged from 5.0 to 14.4 l · min-1 (mean ± SD 8.6 ± 2.0 l · min-1). Bias and limits of agreement (1.96 SD of the bias) were -0.03 ± 0.82 l · min-1 and 1.62 l · min-1, resulting in an overall percentage error of 18.8%. The precision of PCCO-measurements was 17.8%. Insufficient trending ability was indicated by concordance rates of 74% (exclusion zone of 15% (1.29 l · min-1)) and 67% (without exclusion zone), as well as by polar plot analysis. CONCLUSIONS: In neurosurgical patients requiring extensive vasoactive support, CO values obtained by calibrated PCCO showed clinically and statistically acceptable agreement with TPCO-measurements, but the results from concordance and polar plot analysis indicate an unreliable trending ability.

A prospective randomized study comparing retractor-endoscopic vs. open release of carpal tunnel and cubital tunnel syndromes.

OBJECTIVE: To evaluate the neurological and neurophysiological outcomes of retractor-endoscopic versus open release in carpal tunnel syndrome (rCTS and oCTS, respectively) and cubital tunnel syndrome (rCbTS and oCbTS, respectively) at 3- and 12-month follow-up. METHODS: Between 2013 and 2017, 80 patients were prospectively blindly randomized. McGowan scores were used for preoperative grading and outcomes were assessed using a modified Bishop rating system (BRS). Furthermore, incapacity to work, duration of postoperative pain, hypoesthesia, atrophy, subjective weakness, and a subjective assessment of the operative result were analyzed. The differences in the cohorts were evaluated with t-tests and ANOVAs as parametric tests and Kruskal-Wallis and Mann-Whitney U tests as nonparametric tests. RESULTS: The 80 patients underwent retractor-endoscopic or open decompression of the median or ulnar nerve. The rCTS group exhibited significant improvements in neurophysiological data (P = 0.032), shorter periods of postoperative pain (P = 0.03), and less discomfort (P = 0.005), as well as significantly better BRS results after 3 months compared with the oCTS group (P = 0.005). Between the oCbS and rCbTS groups, no significant differences were observed (P > 0.05). Regarding improvements in McGowan scores, no statistically significant differences were observed between the rCTS and oCTS groups after 3 months (P = 0.52) or 12 months (P = 0.86), nor were any observed between the rCbTS and oCbTS groups after 3 months (P = 0.88) or 12 months (P = 0.10). CONCLUSION: Significantly superior results were obtained at short-term follow-up for rCTS, whereas no superiority was found for rCbTS release. This study concluded that this endoscopic procedure is safe as well as and effective and has the potential to achieve better results in carpal tunnel syndrome compared with conventional methods.

Endovascular management of spinal vascular malformations.

Spinal vascular malformations are rare diseases with a wide variety of neurological presentations. In this article, arteriovenous malformations (both from the fistulous and glomerular type) and spinal dural arteriovenous fistulae are described and an overview about their imaging features on magnetic resonance imaging (MRI) and digital subtraction angiography is given. Clinical differential diagnoses, the neurological symptomatology and the potential therapeutic approaches of these diseases which vary depending on the underlying pathology are given. Although MRI constitutes the diagnostic modality of first choice in suspected spinal vascular malformation, a definite diagnosis of the disease and therefore the choice of suited therapeutic approach rests on selective spinal angiography. Treatment in symptomatic patients offers an improvement in the prognosis. In most spinal vascular malformations, the endovascular approach is the method of first choice; in selected cases, a combined or surgical therapy may be considered.

Transcranial Doppler Sonography Defined Vasospasm, Ischemic Brain Lesions, and Delayed Ischemic Neurological Deficit in Younger and Elderly Patients after Aneurysmal Subarachnoid Hemorrhage.

BACKGROUND: Vasospasm, delayed ischemic neurologic deficit (DIND), and ischemic brain lesions after acute subarachnoid hemorrhage (SAH) are associated with increased morbidity and mortality. The purpose of this study was to analyze age cutoffs for vasospasm, DIND, and ischemic brain lesions after SAH. METHODS: This study included 292 aneurysmal SAH patients from January 2005 to December 2015. Patients' data were extracted from a prospective database with measurements of transcranial Doppler sonography. Any vasospasm was defined as a maximum mean flow velocity (MMFV) >120 cm/sec. Severe vasospasms were defined as at least 2 measurements of MMFVs >200 cm/sec or an increase of MMFV >50 cm/sec/24 hours over 2 consecutive days or a new neurologic deficit. All MMFVs >120 cm/sec in absence of severe vasospasm criteria were defined as mild vasospasm. Age-related cutoff values were calculated using receiver operating curve analysis. RESULTS: Any vasospasms occurred in 142 patients and thereof mild vasospasm in 86/142 (60.6%) patients and severe vasospasm in 56/142 patients (39.4%). Significantly higher incidences of any vasospasm (P = 0.005), severe vasospasm (P = 0.003), DIND (P = 0.031), and ischemic brain lesions (P = 0.04) were observed in patients aged <50 years. According to receiver operating curve analysis, the optimal age cutoff was 50 years for the presence of overall vasospasms, severe vasospasms, DIND, and ischemic brain lesions and 65 years for mild vasospasms. CONCLUSIONS: Higher incidences of any vasospasms, severe vasospasms, DIND, and ischemic brain lesions were observed in younger SAH patients.

Placement of External Ventricular Drain: Comparison of Two Methods.

BACKGROUND: Insertion of a frontal external ventricular drain (EVD) is a common emergency procedure in neurosurgery. Malpositioning of the EVD and/or triggering a new intracerebral or intraventricular hemorrhage (nICVH) are typical complications. The standard procedure (SP) uses a tape measure to identify the Kocher's point for placement of a frontal burr hole. A faster alternative to determine the correct position is the freehand technique (FHT). This study compared both techniques with regard to the correct positioning of the EVD tip and the induction catheter-induced nICVH. METHODS: We performed a retrospective analysis of patients who required an EVD for acute or chronic hydrocephalus between January 2013 and March 2014. The study consisted of two groups. In the first group, EVDs were placed with the FHT. In the second group the SP was used. Postoperative computed tomography scans were analyzed regarding correct positioning of the ventricular catheter, malpositioning of the tip of the EVD using a 4-point-scale, and evidence for catheter-induced nICVH. RESULTS: A total of 95 patients could be included. The FHT was performed in 43 cases and the SP in 52 cases. No significant differences between the two groups were found regarding the correct position of the EVD tip (p = 0.38) and nICVH (p = 0.12). There was no significant difference in malpositioning of the EVD tip between the groups (p = 0.34). CONCLUSION: Our results show no significant differences between the two methods with regard to correct position, malpositioning, and nICVH. Thus we conclude that the FHT is a fast, safe, and effective alternative to the SP.

Imaging in spinal vascular disease.

Spinal vascular diseases are rare and constitute only 1% to 2% of all vascular neurologic pathologies. In this article, the following vascular pathologies of the spine are described: spinal arterial infarcts, spinal cavernomas, and arteriovenous malformations (including perimedullary fistulae and glomerular arterivenous malformations), and spinal dural arteriovenous fistulae. This article gives an overview about their imaging features on MRI, MR angiography, and digital subtraction angiography. Clinical differential diagnoses, the neurologic symptomatology, and the potential therapeutic approaches of these diseases, which might vary depending on the underlying pathologic condition, are given.

Pathogenesis, diagnosis and management of pneumorrhachis.

Pneumorrhachis (PR), the presence of intraspinal air, is an exceptional but eminent radiographic finding, accompanied by different aetiologies and possible pathways of air entry into the spinal canal. By reviewing the literature and analysing a personal case of traumatic cervical PR after head injury, we present current data regarding the pathoanatomy, clinical and radiological presentation, diagnosis and differential diagnosis and treatment modalities of patients with PR and associated pathologies to highlight this uncommon phenomenon and outline aetiology-based guidelines for the practical management of PR. Air within the spinal canal can be divided into primary and secondary PR, descriptively classified into extra- or intradural PR and aetiologically subsumed into iatrogenic, traumatic and nontraumatic PR. Intraspinal air is usually found isolated not only in the cervical, thoracic and, less frequently, the lumbosacral regions but can also be located in the entire spinal canal. PR is almost exceptional associated with further air distributions in the body. The pathogenesis and aetiologies of PR are multifold and can be a diagnostic challenge. The diagnostic procedure should include spinal CT, the imaging tool of choice. PR has to be differentiated from free intraspinal gas collections and the coexistence of air and gas within the spinal canal has to be considered differential diagnostically. PR usually represents an asymptomatic epiphenomenon but can also be symptomatic by itself as well as by its underlying pathology. The latter, although often severe, might be concealed and has to be examined carefully to enable adequate patient treatment. The management of PR has to be individualized and frequently requires a multidisciplinary regime.

Spinal dural arteriovenous fistula associated with a spinal perimedullary fistula: case report.

Among spinal cord vascular malformations, dural arteriovenous fistulas (DAVFs) must be distinguished from intradural malformations. The concurrence of both is extremely rare. The authors report the case of a 35-year-old man who suffered from progressive myelopathy and who harbored both a DAVF and an intradural perimedullary fistula. During surgery, both fistulas were identified, confirmed, and subsequently obliterated. The fistulas were located at two levels directly adjacent to each other. Although the incidence of concurrent spinal DAVFs is presumed to be approximately 2%, the combination of a dural and an intradural fistula is exceedingly rare; only two other cases have been reported in the literature. One can speculate whether the alteration in venous drainage caused by the (presumably congenital) perimedullary fistula could possibly promote the production of a second dural fistula due to elevated pressure with concomitant venous stagnation and subsequent thrombosis. The authors conclude that despite the rarity of dual pathological entities, the clinician should be aware of the possibility of the concurrence of more than one spinal fistula in the same patient.

Defining Prolonged Length of Acute Care Stay for Surgically and Conservatively Treated Patients with Spontaneous Intracerebral Hemorrhage: A Population-Based Analysis.

BACKGROUND: The definition of prolonged length of stay (LOS) during acute care remains unclear among surgically and conservatively treated patients with intracerebral hemorrhage (ICH). METHODS: Using a population-based quality assessment registry, we calculated change points in LOS for surgically and conservatively treated patients with ICH. The influence of comorbidities, baseline characteristics at admission, and in-hospital complications on prolonged LOS was evaluated in a multivariate model. RESULTS: Overall, 13272 patients with ICH were included in the analysis. Surgical therapy of the hematoma was documented in 1405 (10.6%) patients. Change points for LOS were 22 days (CI: 8, 22; CL 98%) for surgically treated patients and 16 days (CI: 16, 16; CL: 99%) for conservatively treated patients. Ventilation therapy was related to prolonged LOS in surgically (OR: 2.2, 95% CI: 1.5-3.1; P < 0.001) and conservatively treated patients (OR: 2.5, 95% CI: 2.2-2.9; P < 0.001). Two or more in-hospital complications in surgical patients (OR: 2.7, 95% CI: 2.1-3.5) and ≥1 in conservative patients (OR: 3.0, 95% CI: 2.7-3.3) were predictors of prolonged LOS. CONCLUSION: The definition of prolonged LOS after ICH could be useful for several aspects of quality management and research. Preventing in-hospital complications could decrease the number of patients with prolonged LOS.

In-hospital mortality after pre-treatment with antiplatelet agents or oral anticoagulants and hematoma evacuation of intracerebral hematomas.

Pre-treatment with antiplatelet agents is described to be a risk factor for mortality after spontaneous intracerebral hemorrhage (ICH). However, the impact of antithrombotic agents on mortality in patients who undergo hematoma evacuation compared to conservatively treated patients with ICH remains controversial. This analysis is based on a prospective registry for quality assurance in stroke care in the State of Hesse, Germany. Patients' data were collected between January 2008 and December 2012. Only patients with the diagnosis of spontaneous ICH were included (International Classification of Diseases 10th Revision codes I61.0-I61.9). Predictors of in-hospital mortality were determined by univariate analysis. Predictors with P<0.1 were included in a binary logistic regression model. The binary logistic regression model was adjusted for age, initial Glasgow Coma Score (GCS), the presence of intraventricular hemorrhage (IVH), and pre-ICH disability prior to ictus. In 8,421 patients with spontaneous ICH, pre-treatment with oral anticoagulants or antiplatelet agents was documented in 16.3% and 25.1%, respectively. Overall in-hospital mortality was 23.2%. In-hospital mortality was decreased in operatively treated patients compared to conservatively treated patients (11.6% versus 24.0%; P<0.001). Patients with antiplatelet pre-treatment had a significantly higher risk of death during the hospital stay after hematoma evacuation (odds ratio [OR]: 2.5; 95% confidence interval [CI]: 1.24-4.97; P=0.010) compared to patients without antiplatelet pre-treatment treatment (OR: 0.9; 95% CI: 0.79-1.09; P=0.376). In conclusion a higher rate of in-hospital mortality after pre-treatment with antiplatelet agents in combination with hematoma evacuation after spontaneous ICH was observed in the presented cohort.

In-Hospital Mortality and Complication Rates in Surgically and Conservatively Treated Patients with Spontaneous Intracerebral Hemorrhage in Central Europe: A Population-Based Study.

OBJECTIVE: Secondary complications (SC) after intracerebral hemorrhage (ICH) can worsen outcome and are associated with early death. The purpose of the present study was to determine in-hospital mortality rates and SC after spontaneous ICH during acute care stay in a population-based cohort in central Europe. METHODS: A prospective database of the State of Hesse, Germany, was screened for all patients with the primary diagnosis of spontaneous ICH (International statistical classification-10: I61.0-I61.9) between January 2007 and December 2012. RESULTS: In the examined time period 10,029 patients with spontaneous ICH were identified. The cumulative rate of SC was 39.9% (1, 2, or ≥3 SC were documented in 25.0%, 10.1%, and 4.7%, respectively). The most common SC were pneumonia (15.1%), brain edema (6.5%), cardiac decompensation (5.9%), urogenital infection (5.5%), hydrocephalus (4.6%), epilepsy (3.4%), and rebleeding (3.4%). One, 2, or ≥3 SC were found in 2512 patients (25.0%), 1012 (10.1%), 473 (4.7%) patients, respectively. One SC was only a predictor of in-hospital mortality in conservatively treated patients (odds ratio [OR], 1.3; 95% confidence interval [CI] 1.2-1.5, P< 0.001). With an accumulation of SC to ≥3 the chance of in-hospital death increases for surgically (OR, 3.7, 95% CI 2.3-5.9; P< 0.001) and conservatively (OR, 3.0, 95% CI 2.3-3.9; P< 0.001) treated patients. CONCLUSIONS: Surgical treatment of hematomas is associated with an increased rate of SC, but not with higher mortality rates compared with conservatively treated patients. The prevention of an accumulation of SC could lead to a decrease of in-hospital mortality after spontaneous ICH.

NDRG2 and NDRG4 Expression Is Altered in Glioblastoma and Influences Survival in Patients with MGMT-methylated Tumors.

AIM: The N-myc down-regulated gene (NDRG) family is a group of genes that have predominantly tumor-suppressive effects. The goal of this study was to investigate the expression of NDRG2 and NDRG4 in surgical specimens of human glioblastoma and in normal brain tissue, and to search for correlations with overall (OS) and progression-free survival (PFS). MATERIALS AND METHODS: Samples from 44 patients (31 males, 13 females; mean age±SD=57.4±15.7 years) with primary (n=40) or recurrent glioblastoma (n=4) were analyzed by quantitative real-time polymerase chain reaction and immunohistochemistry, with dimensionless semiquantitative immunoreactivity score (IRS), ranging from 0-30] for expression of NDRG2 and NDRG4. Five non-tumorous autopsy brain specimens were used as controls. RESULTS: On the protein level, expression of NDRG2 was significantly down-regulated in glioblastoma (IRS=3.5±3.0 vs. 8.8±3.3; p=0.001), while expression of NDRG4 was significantly up-regulated (IRS=5.4±3.7 vs. 0.75±0.4 vs, p<0.001). There was no statistically significant difference in PFS between a group of 15 patients with glioblastoma with MGMT methylation and enhanced expression of NDRG4 mRNA who were treated with adjuvant radiochemotherapy (temozolomide and 60 Gy) and a group of patients with low expression of NDRG4 mRNA [10 (range=5.5-14.2) months vs. 21 (range=10.7-31.3) months] (p=0.13). CONCLUSION: Expression of both NDRG2 and NDRG4 genes is significantly altered in glioblastomas. PFS among the patients with glioblastoma with MGMT methylation treated with radiochemotherapy differed significantly in high-expression groups compared to patients without MGMT methlation and without radiochemotherapy (p<0.05).

High-mobility group AT-hook protein 2 expression and its prognostic significance in MGMT methylated and unmethylated glioblastoma.

High-mobility group AT-hook protein 2 (HMGA 2) is a transcription factor associated with malignancy and poor prognosis in a variety of human cancers. We correlated HMGA 2 expression with clinical parameters, survival, and O-6-methylguanine-DNA methyltransferase methylation status (MGMT) in glioblastoma patients. HMGA 2 expression was determined by performing quantitative real-time polymerase chain reaction (qPCR) and immunohistochemistry (IHC) in 44 glioblastoma patients and 5 non-tumorous brain specimens as controls. Gene expression levels of MGMT methylated vs. unmethylated patients, and gene expression levels between patient groups, both for qPCR and IHC data were compared using the Mann-Whitney U test. The relationship between HMGA 2 expression, progression-free survival and overall survival was analyzed using the Kaplan-Meier method and the log-rank test. P-values of <0.05 were considered statistically significant throughout the analyses. The mean age of patients at diagnosis was 57.4 ± 15.7 years, and the median survival was 16 months (SE 2.8; 95% CI, 10.6-21.4). HMGA 2 gene expression was significantly higher in glioblastoma compared to normal brain tissue on qPCR (mean, 0.35; SD, 0.27 vs. 0.03, SD, 0.05) and IHC levels (IRS mean, 17.21; SD, 7.43 vs. 3.20; SD, 1.68) (p=0.001). Survival analysis revealed that HMGA 2 overexpression was associated with a shorter progression-free and overall survival time in patients with methylation (n=24). The present study shows a tendency that HMGA 2 overexpression correlates with a poor prognosis of glioblastoma patients independent of MGMT methylation status. The results suggest that HMGA 2 could play an important role in the treatment of glioblastoma and could have a function in prognosis of this type of cancer.

Imaging of postthalamic visual fiber tracts by anisotropic diffusion weighted MRI and diffusion tensor imaging: principles and applications.

Diffusion weighted MRI offers the possibility to study the course of the cerebral white matter tracts. In the present manuscript, the basics, the technique and the limitations of diffusion tensor imaging and anisotropic diffusion weighted MRI are presented and their applications in various neurological and neurosurgical diseases are discussed with special emphasis on the visual system. A special focus is laid on the combination of fiber tract imaging, anatomical imaging and functional MRI for presurgical planning and intraoperative neuronavigation of lesions near the visual system.

Preoperative mapping of cortical motor function: prospective comparison of functional magnetic resonance imaging and [15O]-H2O-positron emission tomography in the same co-ordinate system.

BACKGROUND: Two of the most widely accepted approaches to map eloquent cortical areas preoperatively are positron emission tomography (PET) and functional magnetic resonance imaging (fMRI). As yet, no study has compared these two modalities within the same frame of reference in tumour patients. AIM: We employed [15O]-H2O-PET and fMRI in patients undergoing presurgical evaluation and compared the results with those obtained by direct electrical cortical stimulation (DECS). METHODS: Twenty-five patients with tumours of different aetiology near the central region were investigated. fMRI and PET were processed using the same methods, i.e. statistical parametric mapping (SPM) without anatomical normalization, and transformed into the same frame of reference. RESULTS: fMRI activity was found in more cranial and lateral sections, i.e. closer to the brain surface, in comparison with PET, which demonstrated parenchymal activation. The mean localization difference between fMRI and PET was 8.1 +/- 4.6 mm (range, 2-18 mm). fMRI and [15O]-H2O-PET could reliably identify the central sulcus, as demonstrated by DECS. CONCLUSIONS: fMRI and [15O]-H2O-PET demonstrate comparable results and are sensitive and reliable tools to map the central region, especially in cases of infiltrating brain tumours. However, fMRI is more prone to artefacts, such as the visualization of draining veins, which may explain the more cranial and lateral activation visualized by fMRI, whereas PET depicts capillary perfusion changes and therefore shows activation closer to the parenchyma.