Volume and densities of chronic subdural haematoma obtained from CT imaging as predictors of postoperative recurrence: a prospective study of 107 operated patients.

BACKGROUND: Chronic subdural haematoma (CSDH) is a common entity in neurosurgery with a considerable postoperative recurrence rate. Computerised tomography (CT) scanning remains the most important diagnostic test for this disorder. The aim of this study was to characterise the relationship between the recurrence of CSDH after treatment with burr-hole irrigation and closed-system drainage technique and CT scan features of these lesions to assess whether CT findings can be used to predict recurrence. METHODS: We investigated preoperative and postoperative CT scan features and recurrence rate of 107 consecutive adult surgical cases of CSDH and assessed any relationship with univariate and multivariate regression analyses. RESULTS: Seventeen patients (15.9 %) experienced recurrence of CSDH. The preoperative haematoma volume, the isodense, hyperdense, laminar and separated CT densities and the residual total haematoma cavity volume on the 1st postoperative day after removal of the drainage were identified as radiological predictors of recurrence. If the preoperative haematoma volume was under 115 ml and the residual total haematoma cavity volume postoperatively was under 80 ml, the probability of no recurrence was very high (94.4 % and 97.4 % respectively). CONCLUSIONS: These findings from CT imaging may help to identify patients at risk for postoperative recurrence.

Epidemic of poisoning caused by scopolamine disguised as Rohypnol tablets.

OBJECTIVE: An epidemic of scopolamine poisonings occurred in Oslo in 2008 among users of illicit drugs, caused by fake Rohypnol pills. The clinical features, diagnostic process, and handling of the epidemic are presented. METHODS: Suspected cases of scopolamine poisoning were extracted by reviewing registration forms from an ongoing prospective clinical study of acute poisonings in Oslo. Medical records of extracted contacts were examined and cases included according to specified clinical criteria. RESULTS: Forty-four cases of probable scopolamine poisoning were registered. Main clinical features were mydriasis, visual hallucinations, plucking behavior, agitation, and coma. No clinical diagnosis of anticholinergic syndrome was made prior to forensic analysis of the tablets, the most frequent diagnosis up to this point being unspecified drug-induced psychosis. Later in the epidemic, scopolamine poisoning became the dominating diagnosis. Ten patients were admitted to psychiatric hospitals, the rest recovered in medical units, or left health care against medical advice. DISCUSSION: Scopolamine poisonings are rare, but the resulting anticholinergic syndrome is well described. The syndrome was not recognized until the forensic analysis result strikingly changed how the patients were diagnosed and handled. A unique aspect of this epidemic was the intoxicating agent being scopolamine-containing tablets looking like Rohypnol, sold and used under the impression of being the latter. CONCLUSION: Recognizing the anticholinergic syndrome is important to provide proper treatment. Forensic analysis was the key to correct diagnosis in this outbreak, demonstrating its importance in verifying an epidemic of poisoning by fake drugs.

Simple dual tasking recruits prefrontal cortices in chronic severe traumatic brain injury patients, but not in controls.

The ability to carry out two tasks simultaneously, dual tasking, is specifically impaired after traumatic brain injury (TBI). The aim of the present study was to investigate the neuronal correlates to this increased dual cost in chronic severe TBI patients (n = 10) compared to healthy controls (n = 11) using functional magnetic resonance imaging (fMRI) at 3 Tesla (T). The tasks were a visual search and a simple two-fingers button press motor task. Performance data demonstrated similar and significant dual task interference in both TBI patients and controls using a linear mixed model. However, principal component analysis showed that TBI patients and controls could be classified into different categories based on motor activity in the single compared to the dual task condition, thus reflecting the increased variability in the performance in the TBI group. Random effects between-group analysis demonstrated significantly reduced activation in the TBI group in both single task conditions in the occipital and posterior cingulate cortices, and for the visual task also in the thalami. This pattern was reversed in the dual task condition with significantly increased activation of a predominantly left lateralized prefrontal-anterior midline-parietal network in the TBI group compared to the controls. The increase in activation occurred within regions described to be engaged in healthy volunteers as dual task cost increases. This finding points to substitution, functional reorganization within the primary network subserving the task, following TBI, and demonstrates more effortful processing. Recruitment of these additional prefrontal resources may be connected to serial rather than parallel processing in low level dual tasking in TBI. Thus, in severe TBI, low level dual task performance depends on increased attentional and executive guidance.

Mapping the primary motor cortex in healthy subjects and patients with peri-rolandic brain lesions before neurosurgery.

OBJECTIVE: The aim of this study was to establish a robust set of motor tasks that could be used to functionally delineate the motor cortex with blood oxygenation level dependent functional magnetic resonance imaging (BOLD fMRI) at 3 T and produce precise functional maps for pre-operative planning and functional neuronavigation. METHOD: Twelve male and four female control subjects were recruited for this study which examined six different motor tasks. Finger-, tongue-, lip- and toe-movements, as well as isometric upper arm- and thigh-contraction tasks were conducted during separate scans on a 3 T MRI scanner. Furthermore, patients that previously had undergone similar motor tasks were reviewed, to evaluate whether this set of tasks was able to be adopted for use in a population of patients with brain lesions. RESULTS: The results of this study indicated that the finger-, toe- and tongue-motor tasks were the most robust in identifying their respective primary motor area. Moreover, all three tasks activated regions at regular intervals along the convexity of the hemisphere, making it possible to functionally delineate the primary motor cortex in both healthy subjects and patients. DISCUSSION: The motor tasks described in this study (toe, finger and tongue) were effective at localizing the primary motor cortex for the purposes of neurosurgical planning. These three tasks produced the highest success rate and resulted in activations at regular intervals along the convexity of the hemisphere, allowing the delineation of the entire motor strip even in the presence of edema and anatomical distortions.

Fractal dimension analysis of MR images reveals grey matter structure irregularities in schizophrenia.

The fractal dimension (FD) was used to reveal brain structure irregularities in patients with schizophrenia. FD provides a unique way of quantifying the shape complexity of cortical folding of the human brain. MR images were obtained from seven patients with schizophrenia that were compared with six healthy control subjects. The MR images were first segmented, and the FD was calculated for the grey/white matter boundary for the whole brain and the hemispheres separately, using the box-counting and Minkowski-Bouligand methods. The results showed that the patients had larger FD values than the controls, for the whole brain volume and right hemisphere.

Diffuse axonal injury in severe traumatic brain injury visualized using high-resolution diffusion tensor imaging.

Traumatic brain injury (TBI) is the most common cause of death and disability in young people. The functional outcome in patients with TBI cannot be explained by focal pathology alone, and diffuse axonal injury (DAI) is considered a major contributor to the neurocognitive deficits experienced by this group. The aim of the present study was to investigate whether diffusion tensor imaging (DTI) offers additional information as to the extent of damage not visualized with standard magnetic resonance imaging (MRI) in patients with severe TBI. Nine chronic male TBI patients and 11 matched healthy controls were recruited. Results of the voxel-based analysis of fractional anisotropy (FA) maps and apparent diffusion coefficient (ADC) maps revealed significant differences in anisotropy in major white matter tracts, including the corpus callosum (CC), internal and external capsule, superior and inferior longitudinal fascicles, and the fornix in the TBI group. The FA and ADC measurements offered superior sensitivity compared to conventional MRI diagnosis of DAI. Region-of-interest (ROI) analyses confirmed these results in the investigated regions. The findings of this study support the hypothesis that severe TBI is accompanied by DAI. The DTI changes were more prominent on the right side that contained the focal pathology in most of the patients and accurately reflected differences in both hemispheres. In conclusion, DTI holds great promise as a diagnostic tool to identify and quantify the degree of white matter injury in TBI patients.

Putting the brain in Jeopardy: a novel comprehensive and expressive language task?

OBJECTIVE: To develop and test a novel fMRI compatible comprehensive and expressive language task that reliably and predictably activates both Wernicke's and Broca's cortical brain regions, respectively, and has utility for the determination of hemispheric language dominance. METHODS: Ten healthy men (seven) and women (three) were administered a task based on the television game Jeopardy that was adapted for fMRI presentation. The task was programmed using E-PRIME software and designed to run as an event-related experiment. The study was conducted on 3 T MRI Phillips Intera scanner, and data was anlysed using Brain Voyager QX. All subjects provided written informed consent. RESULTS: The Jeopardy task produced robust left hemisphere activation in regions corresponding to Wernicke's and Broca's areas. CONCLUSION: This novel fMRI compatible task (Jeopardy) reliably maps both Broca's and Wernicke's areas with robust hemispheric lateralization. It is potentially useful in language localization studies as it offers advantages over conventional procedures and other fMRI tasks by virtue of being non-invasive and mapping both language areas in one experiment.

Brain activation measured using functional magnetic resonance imaging during the Tower of London task.

BACKGROUND: Individuals with traumatic brain injury (TBI) often suffer from a number of enduring cognitive impairments such as in attention, memory, speed of processing information and dual-task performance. OBJECTIVE: The aim of this study was to assess the patterns of regional brain activation in response to the Tower of London (ToL) task in a group of patients suffering from chronic TBI using functional magnetic resonance imaging (fMRI). METHODS: fMRI was performed during performance of the ToL planning task in 10 patients suffering from severe TBI and in 10 age- and sex-matched controls using a 3 T magnetic resonance scanner. RESULTS: Performance data showed no difference in response accuracy between the TBI group and the healthy control group. Statistical parametric brain maps showed that the TBI group activates larger and additional areas of the cerebral cortex than the healthy control group both for tasks and for a subtraction contrast between the tasks. CONCLUSIONS: The results of this study are interpreted as a cortical reorganization inside the executive system of vigilance and working memory in patients with TBI. Both parietal and frontal areas are recruited to compensate for damaged brain tissue.