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SummaryAim - To correlate the magnetic resonance imaging signal changes observed during interstitial laser photocoagulation (ILP) therapy with histopatho-logical analysis of tissue necrosis. A 1.5T MR system was used. Lesions were produced with a diode laser (805 nm) in the liver of normal Wistar rats at laparotomy under general anaesthesia and imaged during treatment. Seventeen lesions were monitored with a T1-weighted spin echo (T1WSE) sequence, and 15 with a FLASH sequence. Treated tissue was removed and stained for NADPH-diaphorase to determine the extent of devitalization. Per-procedural T1WSE showed an expanding area of low signal which developed a high signal rim as ILP progressed. FLASH imaging showed an expanding area of low intensity which was replaced by a complex region of signal change as treatment progressed. Good imaging-histopathological correlation was shown: for T1WSE, r2=0.88 (P < 0.001) and for FLASH, r2=0.95 (P < 0.001). MR imaging during hepatic ILP accurately shows the extent of tis...

Brain iron deposition was assessed at 1.5 T in the caudate nucleus, globus pallidus and frontal and parieto-occipital white matter in 28 human immunodeficiency virus (HIV)-infected patients and 15 control subjects with a new Partially Refocussed Interleaved Multi-Echo sequence by measuring 1/T2, 1/T2* and 1/T2' (i.e., R2, R2* and R2'). There were significant differences in the R2 and R2* of the caudate nucleus (p < 0.0001 and p < 0.05) and the R2, R2* and R2' of the globus pallidus (p < 0.01, p < 0.005 and p < 0.05) in HIV-infected patients compared to control subjects. There was a trend for higher values of R2, R2* and R2' in the globus pallidus and caudate nucleus in HIV-infected patients with later stage HIV disease. These results suggest that there is greater iron deposition in the basal ganglia of HIV-infected patients compared with control subjects, with a predilection for the globus pallidus. The relationship between iron deposition in the brain and various parameters of severity of HIV infection remains uncertain.

Objective. To investigate the prevalence and extent of cerebral changes in patients with systemic lupus erythematosus (SLE) by magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS). Methods. SLE patients (47 women) and controls (25 women) underwent 1.5T MRI. A semiautomated segmentation technique calculated cerebrospinal fluid (CSF) and brain volumes. Proton MRS of the frontal and parieto-occipital white matter yielded metabolite ratios of N-acetyl groups (NA), choline, and creatine. Results. Compared with the control group, the SLE patients more often had cerebral atrophy on MRI (32% versus 0%), confirmed by an increase in the CSF to intracranial volume ratio. The patients also had old infarcts and hemorrhages (8.5% versus 0%) and more small white matter lesions (23% versus 8% had > 5 such lesions). MRS showed relative reduction of NA peaks. Although no patient was studied when acutely ill, prior neurologic involvement was related to abnormal findings. Conclusion. MRI and MRS are helpful in the investigation of cerebral complications of SLE. There are chronic changes which may be ischemic in nature. Their precise cause, consequences, and prevention are current challenges.

SummaryInterstitial laser photocoagulation (ILP) is currently limited by deficient per-procedural monitoring. The purpose of this study was to evaluate MR control of ILP of hepatic metastases. Twenty-two laser activations were used to treat eight metastases in seven patients under local anaesthesia and sedation. Laser energy was delivered via optical fibres positioned in the tumour under ultrasound guidance. T1-weighted FLASH and spin-echo sequences were used to monitor the procedure. Enhanced CT was performed at 24 h to assess thermal necrosis. FLASH imaging showed an enlarging area of signal change during ILP. The final extent of this correlated closely with the extent of tissue necrosis on CT. Spin-echo imaging was disappointing because of poor contrast between the treated tissue and normal liver/untreated tumour. Per-procedural MR imaging accurately and reliably depicts ILP-induced necrosis. MR control may permit more widespread application of ILP to the treatment of hepatic tumours.

Discerning a speaker's gender from their voice is a basic and crucial aspect of human communication. Voice pitch height, the perceptual correlate of fundamental frequency, is higher in females and provides a cue for gender discrimination. However, male and female voices are also differentiated by multiple other spectral and temporal characteristics, including mean formant frequency and spectral flux. The robust perceptual segregation of male and female voices is thought to result from processing the combination of discriminating features, which in neural terms may correspond to early sound object analysis occurring in non-primary auditory cortex. However, the specific mechanism for gender perception has been unclear. Here, using functional magnetic resonance imaging, we show that discrete sites in non-primary auditory cortex are differentially activated by male and female voices, with female voices consistently evoking greater activation in the upper bank of the superior temporal sulcus and posterior superior temporal plane. This finding was observed at the individual subject-level in all 24 subjects. The neural response was highly specific: no auditory regions were more activated by male than female voices. Further, the activation associated with female voices was 1) larger than can be accounted for by a sole effect of fundamental frequency, 2) not due to psychological attribution of female gender and 3) unaffected by listener gender. These results demonstrate that male and female voices are represented as distinct auditory objects in the human brain, with the mechanism for gender discrimination being a gender-dependent activation-level cue in non-primary auditory cortex.

Diabetic 'peripheral' neuropathy (DPN) is one of the common sequelae to the development of both type-1 and type-2 diabetes mellitus. Neuropathy has a major negative impact on quality of life. Abnormalities in both peripheral vasculature and nerve function are well documented and, in addition, evidence is emerging regarding changes within the central nervous system (CNS) that are concomitant with the presence of DPN. The often-resistant nature of DPN to medical treatment highlights the need to understand the role of the CNS in neuropathic symptomatology and progression, as this may modulate therapeutic approaches. Advanced neuroimaging techniques, especially those that can provide quantitative measures of structure and function, can provide objective markers of CNS status. With that comes great potential for not only furthering our understanding of involvement of the CNS in neuropathic etiology but also most importantly aiding the development of new and more effective, targeted, analgesic interventions.

BackgroundThe mechanisms of cerebellar degeneration attributed to prolonged and excessive alcohol intake remain unclear. Additional or even alternative causes of cerebellar degeneration are often overlooked in suspected cases of alcohol-related ataxia. The objectives of this study were two fold: (1) to investigate the prevalence of gluten-related serological markers in patients with alcohol-related ataxia and; (2) to compare the pattern of brain involvement on magnetic resonance imaging between patients with alcohol and gluten ataxias.Materials & methodsPatients diagnosed with alcohol and gluten ataxias were identified from a retrospective review of patients attending a tertiary clinic. HLA genotype and serological markers of gluten-related disorders were recorded. Cerebellar volumetry, MR spectroscopy and voxel-based morphometric analyses were performed on patients and compared with matched control data.ResultsOf 904 registered patients, 104 had alcohol ataxia and 159 had gluten ataxia. 61% of the alcohol ataxia group and 70% of the gluten ataxia group had HLA DQ2/DQ8 genotype compared to 30% in healthy local blood donors. 44% of patients with alcohol ataxia had antigliadin antibodies compared to 12% in the healthy local population and 10% in patients with genetically confirmed ataxias. None of the patients with alcohol ataxia and antigliadin antibodies had celiac disease compared to 40% in patients with gluten ataxia. The pattern of structural brain abnormality in patients with alcohol ataxia who had antigliadin antibodies differed from gluten ataxia and was identical to that of alcohol ataxia.ConclusionsAlcohol related cerebellar degeneration may, in genetically susceptible individuals, induce sensitization to gluten. Such sensitization may result from a primary cerebellar insult, but a more systemic effect is also possible. The duration and amount of exposure to alcohol may not be the only factors responsible for the cerebellar insult.

The purpose of this study was to examine by proton spectroscopy for any difference in cerebral metabolites in patients taking part in the Concorde study (comparing the efficacy of immediate versus deferred treatment with zidovudine on asymptomatic HIV infected individuals). Forty seven HIV positive male patients [29 immediate, 18 deferred zidovudine] were examined in the last 9 months of the therapeutic trial. Magnetic resonance imaging and proton spectroscopy were performed at 1.5 Tesla using a single voxel placed in the parieto-occipital white matter. No significant difference was found in metabolite ratios comparing immediate versus deferred zidovudine (NA/NA+Cho+Cr 0.52 vs. 0.52). High quality spectra were acquired in relatively large numbers of patients and logistically spectroscopy may be applied to clinical therapeutic studies.

White matter change occurs in human immunodeficiency virus (HIV) encephalopathy, which may be difficult to assess subjectively especially in the early stages of disease. This study applies a quantitative approach to the assessment of this finding. Sixty-three HIV seropositive subjects, 47 seronegative blood donors and 17 seronegative homosexual men underwent axial T2 weighted MRI of the brain at 1.5T. Quantitative analysis was performed by obtaining the pixel contrast between parieto-occipital white matter and head of caudate grey matter (Cwg). Highest values of Cwg were found in a subgroup of subjects with AIDS who had diffuse/patchy white matter abnormalities and atrophy on qualitative image assessment. Statistically significant differences were found in Cwg between subjects with high (or = 200 x 10(6)/I) and low (200 x 10(6)/I) CD4 lymphocyte counts (P0.05) and between subjects with and without HIV-1 associated cognitive/motor complex (P0.05). This technique provides an objective measure of diffuse HIV-related parenchymal abnormality seen on T2 weighted MRI.

Predictive coding frameworks of perception propose that neural networks form predictions of expected input and generate prediction errors when the external input does not match expectation. We therefore investigated the processing of unexpected sounds and silence in the auditory cortex using fMRI. Unexpected sounds, when compared to expected sounds, evoked greater activation in large areas of the left temporal and insular cortices. Additionally the left middle temporal gyrus exhibited greater activation to unexpected events in general, whether sounds or silence, when compared to the corresponding expected events. These findings support predictive coding models of perception, which suggest that regions of the temporal cortex function to integrate sensory information with predictive signals during auditory perception.

Subjective assessment of emotional valence is typically associated with both brain activity and autonomic arousal. Accurately assessing emotional salience is particularly important when perceiving threat. We sought to characterize the neural correlates of the interaction between behavioral and autonomic responses to potentially threatening visual and auditory stimuli. Twenty-five healthy male subjects underwent fMRI scanning whilst skin conductance responses (SCR) were recorded. One hundred and eighty pictures, sentences, and sounds were assessed as "harmless" or "threatening." Individuals' stimulus-locked, phasic SCRs and trial-by-trial behavioral assessments were entered as regressors into a flexible factorial design to establish their separate autonomic and behavioral neural correlates, and convolved to examine psycho-autonomic interaction (PAI) effects. Across all stimuli, "threatening," compared with "harmless" behavioral assessments were associated with mainly frontal and precuneus activation with specific within-modality activations including bilateral parahippocampal gyri (pictures), bilateral anterior cingulate cortex (ACC) and frontal pole (sentences), and right Heschl's gyrus and bilateral temporal gyri (sounds). Across stimulus modalities SCRs were associated with activation of parieto-occipito-thalamic regions, an activation pattern which was largely replicated within-modality. In contrast, PAI analyses revealed modality-specific activations including right fusiform/parahippocampal gyrus (pictures), right insula (sentences), and mid-cingulate gyrus (sounds). Phasic SCR activity was positively correlated with an individual's propensity to assess stimuli as "threatening." SCRs may modulate cognitive assessments on a "harmless-threatening" dimension, thereby modulating affective tone and hence behavior.

Introduction Quantitative Electroencephalography (qEEG) has been shown to distinguish AD patients from healthy controls (HC) at a group but not at an individual level. A novel qEEG data analysis method created at the University of Sheffield can measure linear and non-linear levels of brain synchronisation in the time domain. Methods Patients with AD and HV had resting state EEGs. The standard 10–20 international system of EEG electrode placement was used. All patients had MRI and detailed neuropsychology as part of the European VPH-DARE@IT project. Custom made software (Error Reduction Ratio-causality (ERR-causality) analysed average strength of linear and non-linear synchronization in bicentroparietal region. Results 10 HC and 10 AD EEGs were included. Mean ages were 58.1 (AD) versus 62.2 y (HV). Mean mini-mental state examinations were 17.5 (AD) and 28.50 (HV). The ratio of bi-centroparietal synchronisation between eyes open & eyes close (EO/EC) showed a striking difference between the two groups (AD ratio 0.814 versus HC ratio 0.282, p=0.0006). Conclusions These results suggest that patients with AD have higher levels of EO bi-centroparietal synchronisation & in particular the ratio between EO/EC synchronisation has potential to be used as a non-invasive and inexpensive biomarker or diagnostic tool for AD.

This study was carried out using MRI (proton density--and T2-weighted) on 16 HIV-negative controls, 9 symptom-free HIV-positive patients and 25 with CDC IV HIV disease. The studies from this last group had previously been allocated by a radiologist to the following categories: 8 with focal mass lesions and normal-appearing white matter; 9 with diffuse encephalopathy (high signal on T2-weighted images, affecting most or all of the white matter) and 8 with patchy encephalopathy (high signal affecting only one or two areas within the white matter). Moran's I, a statistic of spatial autocorrelation, was calculated for the grey-scale values of a sampled pixel array from a central white matter region of each of the images. All values of Moran's I calculated in this study showed a large positive excess over the expected value under randomisation, indicating highly significant positive auto-correlation in the spatial arrangement of the grey-scale values. On T2-weighted images a statistically significant increase in the mean value of Moran's I, compared with controls, was found in the diffuse encephalopathy group, indicating that quantifiable changes in the spatial autocorrelation of pixel data can be related to recognised qualitative changes in the appearance of white matter in subjects with HIV disease. A lesser, but significant, rise in the mean value of Moran's I was also found in the focal mass lesion group, suggesting that changes in spatial autocorrelation may indicate pathological change in advance of qualitative MRI changes.

More frequently hospital clinicians are reviewing images from MR studies of their patients before seeking formal radiological opinion. This practice is driven by a multitude of factors, including an increased demand placed on hospital services, the wide availability of the picture archiving and communication system, time pressures for patient treatment (eg, in the management of acute stroke) and an inherent desire for the clinician to learn. Knowledge of the basic physical principles behind MRI is essential for correct image interpretation. This article, written for the general hospital physician, describes the basic physics of MRI taking into account the machinery, contrast weighting, spin- and gradient-echo techniques and pertinent safety issues. Examples provided are primarily referenced to neuroradiology reflecting the subspecialty for which MR currently has the greatest clinical application.

The objectives of this paper are (a) to establish the reliability of relative metabolite concentrations determined with (1)H-MR spectroscopy of the cerebellum using a method appropriate to the constraints of clinical radiology and (b) to record normal values for metabolites within the cerebellum and to look for differences in metabolite concentrations between the cerebellar hemispheric white matter and the superior vermis. 3-T (1)H-MR spectra were obtained from voxels positioned in the right cerebellar hemispheric white matter and the superior vermis in 55 healthy adults (mean age 41 years, range 20 to 77) using a single voxel PRESS sequence (TR/TE = 2,000/144 ms). One volunteer (male, age 34 years) was examined in six separate sessions over a period of 3 weeks. Reliability of intra- and inter-subject metabolite fitted area ratios was determined by evaluating coefficients of variance (%). Inter- and intra-subject coefficients of variance (%) in metabolite ratios were consistently lower in the vermis (4 to 11.6) compared to those of the hemisphere (7.2 to 14.3). Cho/Cr was significantly higher in the vermis (0.83 ± 0.10) compared to the hemisphere (0.76 ± 0.11) and NAA/Cho was significantly lower in the vermis (1.19 ± 0.12) compared to the hemisphere (1.35 ± 0.16). Low inter- and intra-subject variability can be achieved when using a (1)H-MR spectroscopy technique that is appropriate to the time constraints of clinical radiology. The regional variations of Cho/Cr and NAA/Cho within the hemisphere and vermis should be considered when performing studies of diseases, which may preferentially target a particular cerebellar location.

A diagnostic challenge commonly encountered in neurology is that of an adult patient presenting with ataxia. The differential is vast and clinical assessment alone may not be sufficient due to considerable overlap between different causes of ataxia. Magnetic resonance (MR)-based biomarkers such as voxel-based morphometry, MR spectroscopy, diffusion-weighted and diffusion-tensor imaging and functional MR imaging are gaining great attention for their potential as indicators of disease. A number of studies have reported correlation with clinical severity and underlying pathophysiology, and in some cases, MR imaging has been shown to allow differentiation of conditions causing ataxia. However, despite recent advances, their sensitivity and specificity vary. In addition, questions remain over their validity and reproducibility, especially when applied in routine clinical practice. This article extensively reviews the current literature regarding MR-based biomarkers for the patient with predominantly adult-onset ataxia. Imaging features characteristic of a particular ataxia are provided and features differentiating ataxia groups and subgroups are discussed. Finally, discussion will turn to the feasibility of applying these biomarkers in routine clinical practice.

PURPOSE: To prospectively study the cerebrospinal fluid volume-total intracranial volume ratio (CSF/ICV) in human immunodeficiency virus (HIV)-infected patients at various stages of disease. MATERIALS AND METHODS: A total of 258 volume measurements were obtained with use of a 1.5-T magnetic resonance (MR) imager and the cluster localized automated spherical segmentation technique (which reduces two-dimensional pixel data from dual spin-echo MR images to a one-dimensional histogram) in 69 control subjects and 189 HIV-infected patients. RESULTS: The CSF/ICV was statistically significantly increased in patients with late-stage (Centers for Disease Control and Prevention group IV) acquired immunodeficiency syndrome (AIDS) (0.16 +/- 0.05 [standard deviation]) compared with seronegative control subjects (0.12 +/- 0.03) and patients without symptoms (0.13 +/- 0.03). CONCLUSION: No substantial change in CSF/ICV occurs until development of late-stage AIDS.

OBJECTIVE The pathogenesis of painful diabetic neuropathy (DN) remains undetermined, with both central and peripheral mechanisms implicated. This study investigates whether thalamic perfusion abnormalities occur in painful DN. RESEARCH DESIGN AND METHODS Eighteen subjects with type 1 diabetes (no DN = 6, painful DN = 5, painless DN = 7) and six healthy volunteers (HV) were recruited. Microvascular perfusion characteristics (relative cerebral blood volume [rCBV], flow [rCBF], and transit time [ttFM]) of the thalamus and caudate nucleus were assessed using magnetic resonance perfusion imaging. The caudate nucleus was chosen to serve as an in vivo control region. RESULTS Subjects with painful DN had significantly greater thalamic rCBV (means [SD]; painful DN, 228.7 [19.5]; no DN, 202.3 [25.8]; painless DN, 216.5 [65.5]; HV, 181.9 [51.7]; P = 0.04) and the longest ttFM(s) (painful DN, 38.4 [3.6]; no DN, 35.3 [13.2]; painless DN, 35.9 [13.7]; HV, 33.7 [14.9]; P = 0.07). There was no significant difference in markers of caudate nucleus perfusion. CONCLUSIONS Painful DN is associated with increased thalamic vascularity. This may provide an important clue to the pathogenesis of pain in DN.

Sinusitis poses a difficult clinical challenge in the management of patients with AIDS because of high rates of relapse and the association with unusual pathogens. To determine the prevalence and severity of sinus disease in this group we prospectively analysed the condition of the paranasal sinuses shown on cranial MR scans of 156 patients referred for the investigation of suspected intracranial pathologies. These included 104 HIV seropositive patients, including 93 with an AIDS-defining diagnosis (CDC IV). Forty-two scans were performed on age-matched controls. The scans were timed to control for seasonal variations in sinus disease and were interpreted by two radiologists who were blinded to the clinical and serological status of the patients. Severe mucosal disease (more than one sinus showing > 75% obliteration) or moderate mucosal disease (only one sinus showing > 75% obliteration) was seen in 15.1% (14/93) patients with AIDS and none of the 42 controls (chi 2 = 6.73, P < 0.01). The mean maximum mucosal thickness in patients with AIDS was significantly greater than the control group (P < 0.001) and also significantly greater than in seropositive patients who had not had an AIDS-defining diagnosis (CDC II/III) (P = 0.006). Paranasal sinus mucosal abnormalities seen on MRI are greater in prevalence and severity in patients with AIDS and about one in seven would be expected to have at least one sinus largely obliterated.

Investigating auditory hallucinations that occur in health may help elucidate brain mechanisms which lead to the pathological experience of auditory hallucinations in neuropsychiatric disorders such as schizophrenia. In this study, we investigated healthy individuals who reported auditory hallucinations whilst falling asleep (hypnagogic hallucinations; HG) and waking up (hypnopompic hallucinations; HP). In an initial behavioural study, we found that subjects with a history of auditory HG/HP hallucinations (n = 26) reported significantly greater subjective sensitivity to environmental sounds than non-hallucinator controls (n = 74). Then, two fMRI experiments were performed. The first examined speech-evoked brain activation in 12 subjects with a history of auditory HG/HP hallucinations and 12 non-hallucinator controls matched for age, gender and IQ. The second fMRI experiment, in the same subjects, probed how brain activation was modulated by auditory attention using a bimodal selective attention paradigm. In the first experiment, the hallucinator group demonstrated significantly greater speech-evoked activation in the left supramarginal gyrus than the control group. In the second experiment, directing attention towards the auditory (vs. visual) modality induced significantly greater activation of the anterior cingulate gyrus in the hallucinator group than in the control group. These results suggest that hallucination proneness is associated with increased sensitivity of auditory and polysensory association cortex to auditory stimulation, an effect which might arise due to enhanced attentional bias from the anterior cingulate gyrus. Our data support the overarching hypothesis that top-down modulation of auditory cortical response characteristics may be a key mechanistic step in the generation of auditory hallucinations.

Purpose Sentinel lymph node biopsy (SLNB) and axillary lymph node dissection (ALND) are used to assess axillary nodal status in breast cancer, but are invasive procedures associated with morbidity, including lymphoedema. This systematic review evaluates the diagnostic accuracy of positron emission tomography (PET), with or without computed tomography (CT), for assessment of axillary nodes in early breast cancer. Methods Eleven databases including MEDLINE, EMBASE and the Cochrane Library, plus research registers and conference proceedings, were searched in April 2009. Study quality was assessed using the QUality Assessment of Diagnostic Accuracy Studies (QUADAS) checklist. Sensitivity and specificity were meta-analysed using a bivariate random effects approach. Results Across 26 studies evaluating PET or PET/CT ( n = 2591 patients), mean sensitivity was 63% (95% CI: 52–74%; range 20–100%) and mean specificity 94% (95% CI: 91–96%; range 75–100%). Across 7 studies of PET/CT ( n = 862), mean sensitivity was 56% (95% CI: 44–67%) and mean specificity 96% (90–99%). Across 19 studies of PET-only ( n = 1729), mean sensitivity was 66% (50–79%) and mean specificity 93% (89–96%). Mean sensitivity was 11% (5–22%) for micrometastases (≤2 mm; five studies; n = 63), and 57% (47–66%) for macrometastases (>2 mm; four studies; n = 111). Conclusions PET had lower sensitivity and specificity than SLNB. Therefore, replacing SLNB with PET would avoid the adverse effects of SLNB, but lead to more false negative patients at risk of recurrence and more false positive patients undergoing unnecessary ALND. The present evidence does not support the routine use of PET or PET-CT for the assessment of the clinically negative axilla.

The medial lemniscus is part of the main somatosensory pathways ascending within the brainstem. It is formed by the heavily myelinated axons of the second order neurones of the dorsal column nuclei. This pathway ascends through the rostral medulla, pons and mesencephalon to finally terminate by synapsing with third order neurones in the ventral posterior nucleus of the thalamus. The medial lemniscus conveys proprioception and fine tactile discrimination as part of the somatosensory system. Conventional MRI studies of the brainstem have been relatively poor in demonstrating these fibre pathways. Diffusion tensor imaging and tractography may demostrated fibre pathways in the brainstem. These techniques do however suffer from relatively poor spatial resolution and some degree of image distortion – especially if based on echo planar imaging techniques. Knowledge of the anatomical relationships of the medial lemniscus is important for the understanding of clinical manifestations of disease processes affecting the somatosensory pathways and also to demonstrate important adjacent structures. Specifically, the pedunculopontine nucleus (PPN) lies in close anatomical relationship to the medial lemniscus and the decussation of the superior cerebellar peduncle. This nucleus is a promising target for deep brain stimulator placement for alleviation of non-dopamine responsive dystonias. Six healthy male volunteers (mean age 33 years) were imaged at 3 Tesla. Imaging protocols consisted of thin section, high resolution, fat suppressed T1-weighted sequences as well as thin section, high isotropic resolution diffusion tensor imaging (DTI), which was analysed to generate colour fractional anisotropy (FA) maps. These were correlated with the fat suppressed T1 weighted images. In all volunteers the medial lemniscus was seen as a pair of bands of low signal on axial, high resolution, fat suppressed T1-weighted images. They were indentified through the upper medulla, pons and mesencephalon. They correlated well with the head to foot orientated fibres on the colour FA maps generated from the DTI data. This study of normal volunteers has illustrated the value of high resolution, fat suppressed T1-weighted images in demonstrating the anatomy of the heavily myelinated medial lemniscus within the brainstem. These high resolution images with good spatial accuracy can potentially be used to aid the localisation of other nuclei, such as the PPN.

Modeling of flow in intracranial aneurysms (IAs) requires flow information at the model boundaries. In absence of patient-specific measurements, typical or modeled boundary conditions (BCs) are often used. This study investigates the effects of modeled versus patient-specific BCs on modeled hemodynamics within IAs. Computational fluid dynamics (CFD) models of five IAs were reconstructed from three-dimensional rotational angiography (3DRA). BCs were applied using in turn patient-specific phase-contrast-MR (pc-MR) measurements, a 1D-circulation model, and a physiologically coherent method based on local WSS at inlets. The Navier–Stokes equations were solved using the Ansys®-CFX™ software. Wall shear stress (WSS), oscillatory shear index (OSI), and other hemodynamic indices were computed. Differences in the values obtained with the three methods were analyzed using boxplot diagrams. Qualitative similarities were observed in the flow fields obtained with the three approaches. The quantitative comparison showed smaller discrepancies between pc-MR and 1D-model data, than those observed between pc-MR and WSS-scaled data. Discrepancies were reduced when indices were normalized to mean hemodynamic aneurysmal data. The strong similarities observed for the three BCs models suggest that vessel and aneurysm geometry have the strongest influence on aneurysmal hemodynamics. In absence of patient-specific BCs, a distributed circulation model may represent the best option when CFD is used for large cohort studies.

Our ability to interact physically with objects in the external world critically depends on temporal coupling between perception and movement (sensorimotor timing) and swift behavioral adjustment to changes in the environment (error correction). In this study, we investigated the neural correlates of the correction of subliminal and supraliminal phase shifts during a sensorimotor synchronization task. In particular, we focused on the role of the cerebellum because this structure has been shown to play a role in both motor timing and error correction. Experiment 1 used fMRI to show that the right cerebellar dentate nucleus and primary motor and sensory cortices were activated during regular timing and during the correction of subliminal errors. The correction of supraliminal phase shifts led to additional activations in the left cerebellum and right inferior parietal and frontal areas. Furthermore, a psychophysiological interaction analysis revealed that supraliminal error correction was associated with enhanced connectivity of the left cerebellum with frontal, auditory, and sensory cortices and with the right cerebellum. Experiment 2 showed that suppression of the left but not the right cerebellum with theta burst TMS significantly affected supraliminal error correction. These findings provide evidence that the left lateral cerebellum is essential for supraliminal error correction during sensorimotor synchronization.

Background/Aims: Visuospatial impairments are known to occur in Alzheimer’s disease (AD). We hypothesised that functional magnetic resonance imaging (fMRI) response in task-related brain regions would be impaired in patients with AD during the task and that treatment with acetyl cholinesterase inhibitors would enhance activations in brain regions concerned with this visual perceptual processing. Method: Ten AD subjects were neuropsychologically assessed and underwent fMRI imaging whilst performing a series of visuospatial perception tasks, before and after treatment with acetyl cholinesterase inhibitors. Eleven healthy elderly comparison subjects were also scanned twice. Results: Regions of increased brain activation in AD included the left precuneus, left cuneus, left supramarginal gyrus, right parieto-temporal cortex and right inferior parietal lobule. Further, increased activation in the left precuneus was found to correlate significantly with improved functioning of activities of daily living. Conclusions: We believe this to be the first fMRI study that, after controlling for the confound of repeat scanning, demonstrates altered patterns of brain activation associated with visuospatial processing following treatment in patients with AD. The treatment-related improvement of visual perception in AD may rely on enhanced attentional mechanisms, thereby possibly supporting independent living through improvement on activities of daily living.

The volumetric flow rate (VFR) waveform over the cardiac cycle in the cerebral vasculature is a significant factor in many studies, which involve cerebrovascular function. Perhaps contrary to expectation, the literature in this area is sparse and the characteristics of blood flow waveforms are ill defined. A better understanding of the variation of blood flow rate and pulsatility may aid our knowledge of risk factors involved in diseases and conditions, such as stroke, arteriovenous malformation, or aneurysm rupture. This study sought to characterise the blood flow waveform over the cardiac cycle at levels within the carotid artery and basilar artery (BA) in a normal cohort. The study cohort consisted of 22 subjects (recruitment age: 20 to 40 years) with no history of vascular disease (median age=26 years, interquartile range=25 to 32 years). Two-dimensional quantitative phase-contrast magnetic resonance imaging was performed on each subject at nine anatomic locations within the carotid artery and BA. Significant differences in pulsatility were present within the carotid tree. Archetypal VFR waveforms were established for this group at the nine locations. A normal individual's VFR waveform at a location within the carotid tree can be estimated by taking the group's archetypal waveform for that location, and scaling by the individual's average flow rate.

Rachel E Musson MBCHB MRCP, Ruth Batty MBBS MRCP FRCR, Santosh R Mordekar MD MRCP MRCPCH, Iain D Wilkinson PHD ARCP FIPEM, Paul D Griffiths PHD FRCR, Daniel JA Connolly BSC MRCP FRCR 1 Radiology Department, Royal Hallamshire Hospital, Sheffield, UK. 2 Department of Neurology, Sheffield Children's Hospital, Sheffield, UK. 3 Academic Unit of Radiology, University of Sheffield, Sheffield, UK. 4 Radiology Department, Sheffield Children's Hospital, Sheffield, UK. Correspondence to: rachel.musson@sth.nhs.uk

Background: We were finding volunteers for functional magnetic resonance imaging studies with abnormalities requiring referral surprisingly frequently. The bioethics surrounding the incidental findings are not straightforward and every imaging institution will encounter this situation in their normal volunteers. Yet the implications for the individuals involved may be profound. Should all participants have review of their imaging by an expert and who should be informed? Methods: The normal volunteers that were imaged with magnetic resonance (MR) which were reviewed by a consultant neuroradiologist. All participants completed a volunteer consent form in addition to a standard departmental MR safety screening form. The volunteer screening form requires the general practitioner details to be completed and asks the participant to consider closely the possibility and implications of finding an unexpected but potentially serious abnormality before signing. Results: 525 different individuals were scanned as normal volunteers, the mean age was 35-years and 330 were males. Of these 525, 46 had definite significant abnormalities (8.8%), mean age 50-years. Conclusion: We have found a high rate of incidental abnormalities amongst individuals participating in imaging studies at our institution. It is our current practice to inform the research study participant of the findings, counsel them and inform their primary care physician. We think that it is advisable for researchers utilising MR imaging of the brain to have access to trained neuroradiologists, a protocol in place to deal with this problem and take consent in a way that allows the participant to realise the possibility of an abnormal finding.

In vivo1H spectroscopy using the STEAM sequence for localization has been applied to the human kidney in normal volunteers and subjects with succesful renal transplants. We show that, within the resolution of our measurements, trimethylamines are present in the spectra from some of the subjects and absent from others, the prominent peak seen at 5.8 ppm in the spectrum is identified as that from urea and not lipid, as previously suggested. © 1991 Academic Press, Inc.

Developmental dyslexia is associated with problems in a range of linguistic and non-linguistic skills. Some of those problems have been attributed to dysfunction of the cerebellum and its associated neural systems. Two studies of cerebellar structure were undertaken by our group. In Study 1, white and grey matter volumes in the cerebellum were investigated in 10 dyslexic and 11 control adult male, right-handed participants using whole-brain volumetric MRI (3D-T1-weighted data sets with a spatial resolution of 0.8 x 0.8 x 0.8 mm(3)). The key finding was that the dyslexic group had a larger volume of white matter in both cerebellar hemispheres, differences that remained significant even when adjusting for total cerebellar volume. In Study 2, with the same participants, long-echo-time proton spectroscopy was used to investigate the ratios of the metabolites choline (Cho), N-acetylaspartate (NAA), and creatine (Cr) in the cerebellar hemispheres and vermis. Two significant differences were found: The dyslexic group had a lower ratio of NAA/Cho in the right cerebellar hemisphere together with a higher ratio of Cho/Cr in the left cerebellar hemisphere. Although it is difficult to interpret the volumetric and spectroscopic results unambiguously, taken together they suggest two possible interpretations: excessive connectivity or abnormal myelination.

Although clear peripheral nerve pathological abnormalities have been demonstrated in diabetic peripheral neuropathy (DPN), there is little information with regard to brain involvement. Our aim was to use in vivo proton magnetic resonance specroscopy (H-MRS) in patients with DPN in order to assess the neuro-chemical status of the thalamus, which acts as the gateway to the brain for somatosensory information.Participants included 18 type 1 diabetic men (eight without DPN, ten with DPN) and six non-diabetic healthy volunteers, who all underwent detailed clinical and neurophysiological assessments yielding a Neuropathy Composite Score (NCS) derived from Neuropathy Impairment Score of the Lower Limbs plus seven tests of nerve function prior to investigation via a single-voxel H-MRS technique, which was used to sample ventral posterior thalamic parenchyma. Spectroscopic resonances including those due to N-acetyl aspartate (NAA) were assessed at both short and long echo-time, providing putative indicators of neuronal function and integrity, respectively.At long echo-time we observed significantly lower NAA:creatine (p = 0.04) and NAA:choline (p = 0.02) ratios in DPN patients than in the other groups. No group differences were detected at short echo-time. We found a significant positive association between both sural amplitude (rho = 0.61, p = 0.004) and nerve conduction velocity (r = 0.58, p = 0.006) and NAA:creatine signal among participants with diabetes. Vibration detection threshold (rho = -0.70, p = 0.004) was significantly related to NAA:choline ratio. Heart rate variability with deep breathing (rho = -0.46, p = 0.05) and NCS (rho = -0.53, p = 0.03) were significantly related to NAA:creatine ratio.The significantly lower NAA:creatine ratio in DPN is suggestive of thalamic neuronal dysfunction, while the lack of difference in short echo-time between the groups does not suggest neuronal loss. Taken together with the observed correlations between NAA and neurophysiological assessments, these findings provide evidence for thalamic neuronal involvement in DPN.

The aim of this study was to assess the ability of a semiautomated process to produce three-dimensional reconstructions of the ventricles and calculate ventricular volumes from magnetic resonance (MR) imaging data in children with structural brain abnormalities.Fourteen children referred for MR imaging of the brain for neurologic symptoms were selected. Seven participants had structural brain abnormalities on MR imaging; seven further participants were age-matched controls with normal brain morphology. MR imaging included T1-weighted volumetric images in all cases. Semiautomated postprocessing techniques were performed on the MR imaging data to generate three-dimensional reconstructions of the ventricles. These were analyzed for morphologic changes, and volumes were calculated. Inter- and intrarater agreement of ventricular volumes were calculated.This technique produced detailed three-dimensional reconstructions of the ventricles, even in children with grossly abnormal ventricular morphology. All MR imaging data were successfully postprocessed in5 minutes. Inter- and intrarater reliability was excellent, with correlation coefficients of 0.99 and 0.92, respectively.This methodology can create detailed three-dimensional visualizations and volumetric measurements of morphologically abnormal ventricles. This technique could help physicians and parents comprehend abnormal ventricular anatomy better and may have future clinical uses in monitoring disease progression or neurosurgical planning.

In this study, we investigated the mechanism for the left cerebral hemisphere's dominance for speech perception. We utilized the crossover of auditory pathways in the central nervous system to present speech stimuli more directly to the left hemisphere (via the right ear) and right hemisphere (via the left ear). Using functional MRI, we found that estimated duration of neural response in the left auditory cortex increased as more speech information was directly received from the right ear. Conversely, response duration in the right auditory cortex was not modulated when more speech information was directly received from the left ear. These data suggest that selective temporal responding distinguishes the dominant from nondominant hemisphere of the human brain during speech perception.

X-linked cerebral adrenoleukodystrophy is an aggressive, rapidly progressive disorder resulting in considerable morbidity and, left untreated, mortality. Patients typically present before the age of 10 years with progressive symptomatology including ataxia, spasticity, and focal neurological deficits. Current therapeutic options are limited, the treatment of choice being haemopoietic stem cell transplantation (HSCT). Intervention is beneficial to those children with early disease and characteristic magnetic resonance (MR) imaging changes. Developments in MR imaging have led to the incorporation of MR spectroscopy in the assessment tools; however, it is yet to be included in stratified assessment tools to guide treatment choice. Furthermore, there remains a paucity of outcome data on MR spectroscopy changes following HSCT. We describe our experience in two males with confirmed cerebral adrenoleukodystrophy treated, at the mean age of 5 years 6 months, with HSCT and report the pronounced spectroscopic changes observed following treatment. Both children, observed for a minimum period of 14 months following treatment, demonstrate complete reversal in previously deteriorating spectroscopy with marked increase in N-acetyl-aspartate (NAA)/choline (Cho) ratios and reduction in Cho/creatine (Cr) ratios following HSCT treatment with concomitant stabilization of clinical status.

This study examined interactive effects of sex and age on prefrontal brain anatomy in humans. It specifically targeted ranges of the adult life span and regions of cortex that previously showed male-female differences. Participants were 68 healthy human males and females aged 20-72 years. Data collection and analysis were conducted in parallel across two cohorts (laboratories) to investigate reproducibility of effects in relation to sex and age. Volumes for four regional prefrontal subfields per hemisphere were obtained from high-resolution MRI. Regional sex by age interactions were replicated across cohorts. In men, age effects were greatest in medial prefrontal volume, with decreases in dorsal medial and orbital medial regions. In women, age-related changes in medial prefrontal regions were limited to the dorsal volume, with additional decreases observed in lateral subfields. Cohort and Cohort x Age effects in total brain and total prefrontal volume were linked to a combination of methodological and sampling-related factors. Findings indicated that neuroanatomical changes throughout adulthood unfold along different time scales in men and women. Results also showed that sex differences in ageing localized to medial prefrontal regions were particularly robust to variation across cohorts.

Purpose: To evaluate if two gadolinium perfusion studies can be performed during the same table occupancy without degradation of the derived data in the second study. Material and Methods: Magnetic resonance (MR) perfusion studies of the whole brain were performed on 12 patients during the administration of two gadolinium boluses separated by 8 min. In six patients, gadolinium was given as two 20-ml administrations of standard 0.5 M chelate (Magnevist), whilst the other six patients received two 10-ml administrations of 1.0 M chelate (Gadovist). Results: There were no significant differences in subjective quality between the time–intensity curves of the first and second perfusion studies using either the 0.5 M or 1.0 M gadolinium chelate. The objective measurements in quality of the time–intensity curves (maximum signal change and full width at half maximum) changed by less than 5% of the original values on the second perfusion study. The first-moment mean transit times did not change significantly on the sequential studies. The regional cerebral blood volume tended to increase on the second study (by 15% on average), but this did not reach statistical significance. Conclusion: The results from two sequential dynamic gadolinium-based perfusion studies can be compared in a meaningful manner using the technique described.

Purpose: To evaluate the effects of spatial normalization on volume rendering in cases of pediatric brain malformation. Material and Methods: Three-dimensional (3D) T1-weighted volume datasets were acquired in three children, one with pachygyria, one with a Dandy-Walker malformation associated with polymicrogyria, and one with dysgenesis of the corpus callosum. On the non-normalized datasets, the skull margins were cropped and the remainder stripped with the brain extraction technique (BET). The data were also normalized into standard anatomic reference space using pediatric templates prior to the BET script. The surface constructions obtained by both techniques were then compared for geometric distortions. Results: Normalization of 3D datasets resulted in significant distortions in the shape of the brain, with increased anterior–posterior dimensions and narrower transverse diameter in all three cases. In two cases, there were alterations in the appearance of the gyri and sulci, leading to a potential misinterpretation of the volume-rendered surface when the gyri and sulci were in fact normal. Conclusion: In pediatric brain, particularly those with congenital brain anomalies, normalization as a post-processing step should be avoided as this may lead to misrepresentation of brain morphometry.

Difficulty with social interactions is a characteristic of schizophrenia. The authors used functional magnetic resonance imaging (fMRI) to investigate brain activation changes during a social cognition paradigm in patients with schizophrenia during and after an acute episode and their association with social and executive function.In a longitudinal study design, 14 patients with schizophrenia experiencing an acute episode had an fMRI scan. They returned for a follow-up scan after clinical improvement. Fourteen healthy comparison subjects were also scanned twice with approximately the same time interval between scans as in the patient group. The authors employed a social cognition fMRI paradigm involving empathic and forgivability judgments. Schizophrenia symptoms, social functioning and illness insight scales, and the Wisconsin Card Sorting Test were used to examine whether improvement on these measures was associated with recovery of brain activation in response to the social cognition paradigm.After recovery from the acute episode, patients exhibited increased activation in the left medial prefrontal cortex, which was, in turn, significantly correlated with improved insight and social functioning. Decreased symptom severity and improved performance on the Wisconsin Card Sorting Test were not significantly associated with increased left medial prefrontal cortex activation.This is the first study to the authors' knowledge to use a social cognition paradigm to reveal improved left medial prefrontal cortex activation in schizophrenia after recovery from an acute episode. These results suggest that restored left medial prefrontal cortex activation may mediate improvement of insight and social functioning in patients with schizophrenia.

Alzheimer's disease (AD) is associated with widespread brain atrophy including structures subserving memory. We applied an improved structural detection methodology to examine the less well known progression of atrophy in early-stage AD. We sought to i) longitudinally study volumetric differences in patients with early-stage AD and healthy volunteers; and ii) test the hypothesis that hippocampal volumes would be correlated with clinically relevant cognitive function. Seven patients and eleven healthy subjects underwent two structural MRI scans and neuropsychological assessments. Scans were normalised to a study-specific template and 'morphologically opened' to reduce tissue misclassification. Using brain-parcellation, patient atrophy was localised to left fusiform and parahippocampal gyri, whilst left hippocampal volumes were correlated with a cognitive performance measure. A whole-brain search methodology, showed that patients had reduced volumes including fronto-temporal regions bilaterally, in hippocampi and amygdalae and right cerebellum. Whole-brain correlational analyses revealed that cognitive performance was correlated with volumes of both hippocampi, superior temporal gyri and left insula. Neither group exhibited significant longitudinal volumetric changes. Utilising a novel methodology, we have shown that in early-stage AD, clinically relevant cognitive deficits are correlated with regionally specific grey-matter volumes, which are detectable at an early stage of the illness.

Glucocorticoid analogues are often administered to patients with intracranial space-occupying lesions. Clinical response can be dramatic, but the neurophysiological response is not well documented. This study sought to investigate the blood-lesion barrier, blood-brain barrier, and cerebral perfusion characteristics of patients who have undergone such therapy using magnetic resonance imaging.Seventeen patients with intracranial mass-enhancing lesions underwent magnetic resonance imaging before and after 3 days of high-dose dexamethasone therapy. Assessments of blood-lesion barrier and blood-brain barrier integrity were based on a dynamic T1-weighted exogenous contrast technique that yielded the normalized maximal change in contrast uptake (T1-uptake). Perfusion was assessed using a dynamic T2*-weighted exogenous contrast technique to yield relative regional cerebral blood volume and first-moment mean transit time. Comparisons were made in T1-uptake, regional cerebral blood volume, and first-moment mean transit time of both enhancing lesion and contralateral normal-appearing white matter (CNAWM) obtained before and after dexamethasone.Significant reduction in T1-uptake was observed (19% decrease, P0.005) within enhancing pathological tissue, whereas no significant alteration was detected in CNAWM. Regional cerebral blood volume was significantly reduced in both enhancing tissue (28% decrease, P0.005) and in CNAWM (20% decrease, P0.001). Bolus first-moment mean transit time significantly increased (2.0 s prolongation, P0.05) in CNAWM, whereas there was no significant change (1.4 s prolongation, P0.05) within enhancing tissue.Glucocorticoid-analogue therapy not only affects the permeability of the blood-lesion barrier and lesion blood volume but also affects blood flow within normal-appearing contralateral parenchyma. There is a need for controls in steroid therapy in magnetic resonance imaging studies, which involve assessments of cerebrovascular function.

Objectives: To determine the neurobiochemical sequelae of oral creatine monohydrate supplementation in active athletes. Design/Participants: Eighteen sportsmen underwent single-voxel proton magnetic resonance spectroscopy of the deep frontal cerebral white matter before and after 5 days of oral ingestion: 12 of 18 swallowed 4 x 5 g creatine monohydrate per day, and the remaining swallowed a placebo. Main Outcome Measurements: Creatine, choline, and N-acetyl spectral resonances were evaluated at both long (135 ms) and short (20 ms) echo times. Results: A mixed-design factorial ANOVA demonstrated no interaction over time in any of the measures (P at least 0.081). Conclusions: The results suggest that, for the given dosage regimen, ingested creatine augmentation does not alter the magnetic resonance visible creatine pool in the deep frontal cerebral white matter of young active sportsmen.

We investigated the role of magnetic resonance angiography (MRA) in the early follow-up of patients after stereotactic radiosurgery (STRS) for cerebral arteriovenous malformations (AVMs) and determined the influence of individual morphological factors of AVMs in early response to treatment. A group of 40 patients (41 AVMs) consented to a dedicated 1.5-T MR protocol 12 months after receiving STRS for a brain AVM. In addition to standard spin echo sequences, 3-D contrast-enhanced sliding interleaved Ky MRA (CE-SLINKY) and dynamic time-resolved subtraction angiography (MR-DSA) were performed. Nidal volumes were calculated using CE-SLINKY data in patients with a persisting arteriovenous shunt. Planning angiographic data was investigated in all 40 patients. The following AVM factors were used in the statistical analysis to determine their role in nidus obliteration: (1) maximum linear dimension, (2) nidal volume, (3) AVM location (4) nidal morphology, (5) venous drainage, (6) “high-flow angiographic change”, (7) prior embolization, and (8) dose reduction. Complete nidal obliteration was found in 9 patients, 26 showed greater than 50% nidal reduction and 6 had less than 50%. Two AVM factors, venous drainage and AVM location, were found to significantly correlate with rate of obliteration. We successfully demonstrated the use of MRA to quantitatively assess the response of AVMs to STRS. Two AVM factors, venous drainage and AVM location were found to correlate with rate of obliteration prior to the application of the Bonferroni correction, but if this more rigorous statistical test was applied then none of the factors was found to be significant.

Purpose: To report the initial experience of magnetic resonance (MR) digital subtraction angiography (MR-DSA) in the dynamic assessment of the cerebral circulation in acute non-traumatic intracerebral hemorrhage (ICH). Material and Methods: Twelve patients with acute ICH were investigated within 6 days of the ictus using a dynamic contrast-enhanced 2-D MR angiogram that produces subtracted images with a temporal resolution of 1–2 frame/s. The MR-DSA examinations were assessed for evidence of an intracranial vascular abnormality and were compared with (i) the routine MR sequences, (ii) non-dynamic time-of-flight MR angiography, and (iii) catheter angiogram performed during the same admission. Results: All 12 MR-DSA examinations were considered to be technically satisfactory. MR-DSA detected an intracranial vascular abnormality in 7 patients (3 arteriovenous malformations, 2 aneurysms, 1 dural arteriovenous fistula, and 1 venous thrombosis). All abnormalities were confirmed by catheter angiography with the exception of one patient with venous sinus thrombosis found on MR imaging that did not undergo catheter angiography. All four arteriovenous shunts were detected by MR-DSA by virtue of early venous filling. Conclusion: MR-DSA can be performed satisfactorily in the setting of acute ICH and provides an alternative method to catheter angiography for identifying shunting vascular abnormalities such as arteriovenous malformations and fistulae, as well as large aneurysms and venous occlusions. MR-DSA is a contrast-medium-based technique that does not suffer from the T1 shortening effects of acute hemorrhage that can obscure abnormalities on conventional flow-based non-dynamic techniques.

We aimed to investigate cerebellar structural abnormalities and their functional significance in patients with schizophrenia. Forty right-handed men with schizophrenia and 40 sex, age and handedness matched controls underwent a volumetric magnetic resonance scan with 1 mm3 isotropic spatial resolution. Cerebellar grey- and white-matter volumes were analysed using voxel-based morphometry. Patients with schizophrenia completed a battery of neuropsychological tests assessing sustained attention (continuous performance test), memory (Hopkins memory test) and executive function (verbal fluency and Wisconsin card sorting tests). Patients with schizophrenia exhibited significantly increased cerebellar vermis white-matter volume compared with controls. By contrast, total cerebellar volume, and grey- and white-matter volumes of cerebellar hemispheres were not significantly different between groups. Increased vermis white-matter volume in patients was associated with poor verbal fluency performance. We concluded that increased white-matter in the cerebellar vermis, possibly suggesting anomalous connectivity, may be associated with verbal executive dysfunction in men with chronic schizophrenia.

SummaryAvolition affects quality of life in chronic schizophrenia. We investigated the relationship between unconstrained motor activity and the volume of key executive brain regions in 16 male patients with schizophrenia. Wrist-worn actigraphy monitors were used to record motor activity over a 20 h period. Structural magnetic resonance imaging brain scans were parcellated and individual volumes for anterior cingulate cortex and dorsolateral prefrontal cortex extracted. Patients' total activity was positively correlated with volume of left anterior cingulate cortex. These data suggest that the volume of specific executive structures may affect (quantifiable) motor behaviours, having further implications for models of the ‘will’ and avolition.

BackgroundSchizophrenia is associated with widespread cognitive deficits that have an impact on social function. Modafinil promotes wakefulness and is reported to enhance cognition.AimsTo study the acute effects of modafinil administration upon brain activity and cognitive performance in people with chronic schizophrenia.MethodIn a randomised double-blind placebo-controlled crossover design, 19 patients received either modafinil (100 mg) or placebo prior to undertaking a working memory task with functional magnetic resonance imaging.ResultsSeventeen patients completed the study and another underwent acute relapse 4 days post-drug. Modafinil administration was associated with significantly greater activation in the anterior cingulate cortex during the working memory task. The anterior cingulate cortex signal correlated with cognitive performance, although only a subset of patients exhibited ‘enhancement’.ConclusionsModafinil modulates anterior cingulate cortex function in chronic schizophrenia but its beneficial cognitive effects may be restricted to a subset of patients requiring further characterisation.

Gluten sensitivity can manifest with ataxia. The metabolic status of the cerebellum was investigated in 15 patients with gluten ataxia and 10 controls using proton MR spectroscopy. Significant differences were present in mean N-acetyl aspartate levels at short echo time and N-acetyl aspartate/choline ratios at long echo time between the patient and control groups. These data support the hypothesis that cerebellar neuronal physiology differs between patients with gluten ataxia and healthy controls.