Targeted non-invasive brain stimulation boosts attention and modulates contralesional brain networks following right hemisphere stroke

Right hemisphere stroke patients frequently present with a combination of lateralised and non-lateralised attentional deficits characteristic of the neglect syndrome. Attentional deficits are associated with poor functional outcome and are challenging to treat, with non-lateralised deficits often persisting into the chronic stage and representing a common complaint among patients and families. In this study, we investigated the effects of non-invasive brain stimulation on non-lateralised attentional deficits in right-hemispheric stroke. In a randomised double-blind sham-controlled crossover study, twenty-two patients received real and sham transcranial Direct Current Stimulation (tDCS) whilst performing a non-lateralised attentional task. A high definition tDCS montage guided by stimulation modelling was employed to maximise current delivery over the right dorsolateral prefrontal cortex, a key node in the vigilance network. In a parallel study, we examined brain network response to this tDCS montage by carrying out concurrent fMRI during stimulation in healthy participants and patients. At the group level, stimulation improved target detection in patients, reducing overall error rate when compared with sham stimulation. TDCS boosted performance throughout the duration of the task, with its effects briefly outlasting stimulation cessation. Exploratory lesion analysis indicated that response to stimulation was related to lesion location rather than volume. In particular, reduced stimulation response was associated with damage to the thalamus and postcentral gyrus. Concurrent stimulation-fMRI revealed that tDCS did not affect local connectivity but influenced functional connectivity within large-scale networks in the contralesional hemisphere. This combined behavioural and functional imaging approach shows that brain stimulation targeted to surviving tissue in the ipsilesional hemisphere improves non-lateralised attentional deficits following stroke. This effect may be exerted via contralesional network effects.

Brain volume abnormalities and clinical outcomes following paediatric traumatic brain injury

Long-term outcomes are difficult to predict after paediatric traumatic brain injury. The presence or absence of focal brain injuries often do not explain cognitive, emotional and behavioural disabilities that are common and disabling. In adults, traumatic brain injury produces progressive brain atrophy that can be accurately measured and is associated with cognitive decline. However, the effect of paediatric traumatic brain injury on brain volumes is more challenging to measure because of its interaction with normal brain development. Here we report a robust approach to the individualized estimation of brain volume following paediatric traumatic brain injury and investigate its relationship to clinical outcomes. We first used a large healthy control dataset (n > 1200, age 8-22) to describe the healthy development of white and grey matter regions through adolescence. Individual estimates of grey and white matter regional volume were then generated for a group of moderate/severe traumatic brain injury patients injured in childhood (n = 39, mean age 13.53 ± 1.76, median time since injury = 14 months, range 4-168 months) by comparing brain volumes in patients to age-matched controls. Patients were individually classified as having low or normal brain volume. Neuropsychological and neuropsychiatric outcomes were assessed using standardized testing and parent/carer assessments. Relative to head size, grey matter regions decreased in volume during normal adolescence development whereas white matter tracts increased in volume. Traumatic brain injury disrupted healthy brain development, producing reductions in both grey and white matter brain volumes after correcting for age. Of the 39 patients investigated, 11 (28%) had at least one white matter tract with reduced volume and seven (18%) at least one area of grey matter with reduced volume. Those classified as having low brain volume had slower processing speed compared to healthy controls, emotional impairments, higher levels of apathy, increased anger and learning difficulties. In contrast, the presence of focal brain injury and microbleeds were not associated with an increased risk of these clinical impairments. In summary, we show how brain volume abnormalities after paediatric traumatic brain injury can be robustly calculated from individual T1 MRI using a large normative dataset that allows the effects of healthy brain development to be controlled for. Using this approach, we show that volumetric abnormalities are common after moderate/severe traumatic brain injury in both grey and white matter regions, and are associated with higher levels of cognitive, emotional and behavioural abnormalities that are common after paediatric traumatic brain injury.

The European Rare Disease Network for HHT Frameworks for management of hereditary haemorrhagic telangiectasia in general and speciality care

Hereditary haemorrhagic telangiectasia (HHT) is a complex, multisystemic vascular dysplasia affecting approximately 85,000 European Citizens. In 2016, eight founding centres operating within 6 countries, set up a working group dedicated to HHT within what became the European Reference Network on Rare Multisystemic Vascular Diseases. By launch, combined experience exceeded 10,000 HHT patients, and Chairs representing 7 separate specialties provided a median of 24 years' experience in HHT. Integrated were expert patients who focused discussions on the patient experience. Following a 2016-2017 survey to capture priorities, and underpinned by more than 40 monthly meetings, and new data acquisitions, VASCERN HHT generated position statements that distinguish expert HHT care from non-expert HHT practice. Leadership was by specialists in the relevant sub-discipline(s), and 100% consensus was required amongst all clinicians before statements were published or disseminated. One major set of outputs targeted all healthcare professionals and their HHT patients, and include the new Orphanet definition; Do's and Don'ts for common situations; Outcome Measures suitable for all consultations; COVID-19; and anticoagulation. The second output set span aspects of vascular pathophysiology where greater understanding will assist organ-specific specialist clinicians to provide more informed care to HHT patients. These cover cerebral vascular malformations and screening; mucocutaneous telangiectasia and differential diagnosis; anti-angiogenic therapies; circulatory interplays between anaemia and arteriovenous malformations; and microbiological strategies to counteract loss of normal pulmonary capillary function. Overall, the integrated outputs, and documented current practices, provide frameworks for approaches that augment the health and safety of HHT patients in diverse health-care settings.

Axonal marker neurofilament light predicts long-term outcomes and progressive neurodegeneration after traumatic brain injury

[Figure: see text].

Investigating the interaction between white matter and brain state on tDCS-induced changes in brain network activity

Background

Transcranial direct current stimulation (tDCS) is a form of noninvasive brain stimulation whose potential as a cognitive therapy is hindered by our limited understanding of how participant and experimental factors influence its effects. Using functional MRI to study brain networks, we have previously shown in healthy controls that the physiological effects of tDCS are strongly influenced by brain state. We have additionally shown, in both healthy and traumatic brain injury (TBI) populations, that the behavioral effects of tDCS are positively correlated with white matter (WM) structure.

Objectives

In this study we investigate how these two factors, WM structure and brain state, interact to shape the effect of tDCS on brain network activity.

Methods

We applied anodal, cathodal and sham tDCS to the right inferior frontal gyrus (rIFG) of healthy (n = 22) and TBI participants (n = 34). We used the Choice Reaction Task (CRT) performance to manipulate brain state during tDCS. We acquired simultaneous fMRI to assess activity of cognitive brain networks and used Fractional Anisotropy (FA) as a measure of WM structure.

Results

We find that the effects of tDCS on brain network activity in TBI participants are highly dependent on brain state, replicating findings from our previous healthy control study in a separate, patient cohort. We then show that WM structure further modulates the brain-state dependent effects of tDCS on brain network activity. These effects are not unidirectional - in the absence of task with anodal and cathodal tDCS, FA is positively correlated with brain activity in several regions of the default mode network. Conversely, with cathodal tDCS during CRT performance, FA is negatively correlated with brain activity in a salience network region.

Conclusions

Our results show that experimental and participant factors interact to have unexpected effects on brain network activity, and that these effects are not fully predictable by studying the factors in isolation.

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We replicated the brain state and polarity dependent effects of tDCS.

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White matter structure influences tDCS's state-dependent changes in neural activity

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The parameters of tDCS may operate under a hierarchy of influence.

White matter abnormalities in active elite adult rugby players

The recognition, diagnosis and management of mild traumatic brain injuries are difficult and confusing. It is unclear how the severity and number of injuries sustained relate to brain injuries, such as diffuse axonal injury, diffuse vascular injury and progressive neurodegeneration. Advances in neuroimaging techniques enable the investigation of neuropathologies associated with acute and long-term effects of injury. Head injuries are the most commonly reported injury seen during professional rugby. There is increased vigilance for the immediate effects of these injuries in matches, but there has been surprisingly little research investigating the longer-term effects of rugby participation. Here, we present a longitudinal observational study investigating the relationship of exposure to rugby participation and sub-acute head injuries in professional adult male and female rugby union and league players using advanced MRI. Diffusion tensor imaging and susceptibility weighted imaging was used to assess white matter structure and evidence of axonal and diffuse vascular injury. We also studied changes in brain structure over time using Jacobian Determinant statistics extracted from serial volumetric imaging. We tested 41 male and 3 female adult elite rugby players, of whom 21 attended study visits after a head injury, alongside 32 non-sporting controls, 15 non-collision-sport athletic controls and 16 longitudinally assessed controls. Eighteen rugby players participated in the longitudinal arm of the study, with a second visit at least 6 months after their first scan. Neuroimaging evidence of either axonal injury or diffuse vascular injury was present in 23% (10/44) of players. In the non-acutely injured group of rugby players, abnormalities of fractional anisotropy and other diffusion measures were seen. In contrast, non-collision-sport athletic controls were not classified as showing abnormalities. A group level contrast also showed evidence of sub-acute injury using diffusion tensor imaging in rugby players. Examination of longitudinal imaging revealed unexpected reductions in white matter volume in the elite rugby players studied. These changes were not related to self-reported head injury history or neuropsychological test scores and might indicate excess neurodegeneration in white matter tracts affected by injury. Taken together, our findings suggest an association of participation in elite adult rugby with changes in brain structure. Further well-designed large-scale studies are needed to understand the impact of both repeated sports-related head impacts and head injuries on brain structure, and to clarify whether the abnormalities we have observed are related to an increased risk of neurodegenerative disease and impaired neurocognitive function following elite rugby participation.

European Reference Network for Rare Vascular Diseases (VASCERN) position statement on cerebral screening in adults and children with hereditary haemorrhagic telangiectasia (HHT)

Hereditary haemorrhagic telangiectasia (HHT) is a multisystemic vascular dysplasia inherited as an autosomal dominant trait. Approximately 10 % of patients have cerebral vascular malformations, a proportion being cerebral arteriovenous malformations (AVMs) and fistulae that may lead to potentially devastating consequences in case of rupture. On the other hand, detection and treatment related-risks are not negligible, and immediate. While successful treatment can be undertaken in individual cases, current data do not support the treatment of unruptured AVMs, which also present a low risk of bleeding in HHT patients. Screening for these AVMs is therefore controversial.

Structured discussions, distinctions of different cerebrovascular abnormalities commonly grouped into an “AVM” bracket, and clear guidance by neurosurgical and neurointerventional radiology colleagues enabled the European Reference Network for Rare Vascular Disorders (VASCERN-HHT) to develop the following agreed Position Statement on cerebral screening:

1) First, we emphasise that neurological symptoms suggestive of cerebral AVMs in HHT patients should be investigated as in general neurological and emergency care practice. Similarly, if an AVM is found accidentally, management approaches should rely on expert discussions on a case-by-case basis and individual risk-benefit evaluation of all therapeutic possibilities for a specific lesion.

2) The current evidence base does not favour the treatment of unruptured cerebral AVMs, and therefore cannot be used to support widespread screening of asymptomatic HHT patients.

3) Individual situations encompass a wide range of personal, cultural and clinical states. In order to enable informed patient choice, and avoid conflicting advice, particularly arising from non-neurovascular interpretations of the evidence base, we suggest that all HHT patients should have the opportunity to discuss knowingly brain screening issues with their healthcare provider.

4) Any screening discussions in asymptomatic individuals should be preceded by informed pre-test review of the latest evidence regarding preventative and therapeutic efficacies of any interventions. The possibility of harm due to detection of, or intervention on, a vascular malformation that would not have necessarily caused any consequence in later life should be stated explicitly.

We consider this nuanced Position Statement provides a helpful, evidence-based framework for informed discussions between healthcare providers and patients in an emotionally charged area.

Stratifying drug treatment of cognitive impairments after traumatic brain injury using neuroimaging

Cognitive impairment is common following traumatic brain injury. Dopaminergic drugs can enhance cognition after traumatic brain injury, but individual responses are highly variable. This may be due to variability in dopaminergic damage between patients. We investigate whether measuring dopamine transporter levels using 123I-ioflupane single-photon emission computed tomography (SPECT) predicts response to methylphenidate, a stimulant with dopaminergic effects. Forty patients with moderate-severe traumatic brain injury and cognitive impairments completed a randomized, double-blind, placebo-controlled, crossover study. 123I-ioflupane SPECT, MRI and neuropsychological testing were performed. Patients received 0.3 mg/kg of methylphenidate or placebo twice a day in 2-week blocks. Subjects received neuropsychological assessment after each block and completed daily home cognitive testing during the trial. The primary outcome measure was change in choice reaction time produced by methylphenidate and its relationship to stratification of patients into groups with normal and low dopamine transporter binding in the caudate. Overall, traumatic brain injury patients showed slow information processing speed. Patients with low caudate dopamine transporter binding showed improvement in response times with methylphenidate compared to placebo [median change = -16 ms; 95% confidence interval (CI): -28 to -3 ms; P = 0.02]. This represents a 27% improvement in the slowing produced by traumatic brain injury. Patients with normal dopamine transporter binding did not improve. Daily home-based choice reaction time results supported this: the low dopamine transporter group improved (median change -19 ms; 95% CI: -23 to -7 ms; P = 0.002) with no change in the normal dopamine transporter group (P = 0.50). The low dopamine transporter group also improved on self-reported and caregiver apathy assessments (P = 0.03 and P = 0.02, respectively). Both groups reported improvements in fatigue (P = 0.03 and P = 0.007). The cognitive effects of methylphenidate after traumatic brain injury were only seen in patients with low caudate dopamine transporter levels. This shows that identifying patients with a hypodopaminergic state after traumatic brain injury can help stratify the choice of cognitive enhancing therapy.

Diffusion tensor imaging of lumbar spinal nerves reveals changes in microstructural integrity following decompression surgery associated with improvements in clinical symptoms: A case report

The outcomes from spinal nerve decompression surgery are highly variable with a sizable proportion of elderly foraminal stenosis patients not regaining good pain relief. A better understanding of nerve root compression before and following decompression surgery and whether these changes are mirrored by improvements in symptoms may help to improve clinical decision-making processes. This case study used a combination of diffusion tensor imaging (DTI), clinical questionnaires and motor neurophysiology assessments before and up to 3 months following spinal decompression surgery. In this case report, a 70-year-old women with compression of the left L5 spinal nerve root in the L5-S1 exit foramina was recruited to the study. At 3 months following surgery, DTI revealed marked improvements in left L5 microstructural integrity to a similar level to that seen in the intact right L5 nerve root. This was accompanied by a gradual improvement in pain-related symptoms, mood and disability score by 3 months. Using this novel multimodal approach, it may be possible to track concurrent improvements in pain-related symptoms, function and microstructural integrity of compressed nerves in elderly foraminal stenosis patients undergoing decompression surgery.

Development of gynecomastia following initiation of bictegravir/emtricitabine/tenofovir alafenamide

Bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) is a recently approved single-tablet antiretroviral regimen and is recommended as a first-line agent. No cases of gynecomastia were reported in clinical trials. We report development of ultrasound-confirmed gynecomastia in a previously antiretroviral-naïve patient approximately two months after starting BIC/FTC/TAF, which resolved ten weeks after discontinuing bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) based therapy.

Spatial patterns of progressive brain volume loss after moderate-severe traumatic brain injury

Traumatic brain injury leads to significant loss of brain volume, which continues into the chronic stage. This can be sensitively measured using volumetric analysis of MRI. Here we: (i) investigated longitudinal patterns of brain atrophy; (ii) tested whether atrophy is greatest in sulcal cortical regions; and (iii) showed how atrophy could be used to power intervention trials aimed at slowing neurodegeneration. In 61 patients with moderate-severe traumatic brain injury (mean age = 41.55 years ± 12.77) and 32 healthy controls (mean age = 34.22 years ± 10.29), cross-sectional and longitudinal (1-year follow-up) brain structure was assessed using voxel-based morphometry on T₁-weighted scans. Longitudinal brain volume changes were characterized using a novel neuroimaging analysis pipeline that generates a Jacobian determinant metric, reflecting spatial warping between baseline and follow-up scans. Jacobian determinant values were summarized regionally and compared with clinical and neuropsychological measures. Patients with traumatic brain injury showed lower grey and white matter volume in multiple brain regions compared to controls at baseline. Atrophy over 1 year was pronounced following traumatic brain injury. Patients with traumatic brain injury lost a mean (± standard deviation) of 1.55% ± 2.19 of grey matter volume per year, 1.49% ± 2.20 of white matter volume or 1.51% ± 1.60 of whole brain volume. Healthy controls lost 0.55% ± 1.13 of grey matter volume and gained 0.26% ± 1.11 of white matter volume; equating to a 0.22% ± 0.83 reduction in whole brain volume. Atrophy was greatest in white matter, where the majority (84%) of regions were affected. This effect was independent of and substantially greater than that of ageing. Increased atrophy was also seen in cortical sulci compared to gyri. There was no relationship between atrophy and time since injury or age at baseline. Atrophy rates were related to memory performance at the end of the follow-up period, as well as to changes in memory performance, prior to multiple comparison correction. In conclusion, traumatic brain injury results in progressive loss of brain tissue volume, which continues for many years post-injury. Atrophy is most prominent in the white matter, but is also more pronounced in cortical sulci compared to gyri. These findings suggest the Jacobian determinant provides a method of quantifying brain atrophy following a traumatic brain injury and is informative in determining the long-term neurodegenerative effects after injury. Power calculations indicate that Jacobian determinant images are an efficient surrogate marker in clinical trials of neuroprotective therapeutics.

Minocycline reduces chronic microglial activation after brain trauma but increases neurodegeneration

Survivors of a traumatic brain injury can deteriorate years later, developing brain atrophy and dementia. Traumatic brain injury triggers chronic microglial activation, but it is unclear whether this is harmful or beneficial. A successful chronic-phase treatment for traumatic brain injury might be to target microglia. In experimental models, the antibiotic minocycline inhibits microglial activation. We investigated the effect of minocycline on microglial activation and neurodegeneration using PET, MRI, and measurement of the axonal protein neurofilament light in plasma. Microglial activation was assessed using ¹¹C-PBR28 PET. The relationships of microglial activation to measures of brain injury, and the effects of minocycline on disease progression, were assessed using structural and diffusion MRI, plasma neurofilament light, and cognitive assessment. Fifteen patients at least 6 months after a moderate-to-severe traumatic brain injury received either minocycline 100 mg orally twice daily or no drug, for 12 weeks. At baseline, ¹¹C-PBR28 binding in patients was increased compared to controls in cerebral white matter and thalamus, and plasma neurofilament light levels were elevated. MRI measures of white matter damage were highest in areas of greater ¹¹C-PBR28 binding. Minocycline reduced ¹¹C-PBR28 binding (mean Δwhite matter binding = −23.30%, 95% confidence interval −40.9 to −5.64%, P = 0.018), but increased plasma neurofilament light levels. Faster rates of brain atrophy were found in patients with higher baseline neurofilament light levels. In this experimental medicine study, minocycline after traumatic brain injury reduced chronic microglial activation while increasing a marker of neurodegeneration. These findings suggest that microglial activation has a reparative effect in the chronic phase of traumatic brain injury.

Diffusion tensor imaging reveals changes in microstructural integrity along compressed nerve roots that correlate with chronic pain symptoms and motor deficiencies in elderly stenosis patients

Age-related degenerative changes in the lumbar spine frequently result in nerve root compression causing severe pain and disability. Given the increasing incidence of lumbar spinal disorders in the aging population and the discrepancies between the use of current diagnostic imaging tools and clinical symptoms, novel methods of nerve root assessment are needed. We investigated elderly patients with stenosis at L4-L5 or L5-S1 levels. Diffusion tensor imaging (DTI) was used to quantify microstructure in compressed L5 nerve roots and investigate relationships to clinical symptoms and motor neurophysiology. DTI metrics (i.e. FA, MD, AD and RD) were measured at proximal, mid and distal segments along compressed (i.e. L5) and intact (i.e. L4 or S1) nerve roots. FA was significantly reduced in compressed nerve roots and MD, AD and RD were significantly elevated in the most proximal segment of the nerve root studied. FA was significantly correlated with electrophysiological measures of root function: minimum F-wave latency and peripheral motor conduction time (PMCT). In addition, FA along the compressed root also correlated with leg pain and depression score. There was also a relationship between RD and anxiety, leg pain and disability score and AD correlated with depression score. Taken together, these data show that DTI metrics are sensitive to nerve root compression in patients with stenosis as a result of age-related lumbar degeneration. Critically, they show that the changes in microstructural integrity along compressed L5 nerve roots are closely related to a number of clinical symptoms associated with the development of chronic pain as well as neurophysiological assessments of motor function. These inherent relationships between nerve root damage and phenotype suggest that the use DTI is a promising method as a way to stratify treatment selection and predict outcomes.

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DTI can be used to quantify lumbar spinal nerve root compression in elderly patients.

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Diffusion parameters correlate with functional neurophysiology and clinical symptoms.

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DTI has the potential to be used to predict treatment outcomes.

Altered caudate connectivity is associated with executive dysfunction after traumatic brain injury

Traumatic brain injury often produces executive dysfunction. This characteristic cognitive impairment often causes long-term problems with behaviour and personality. Frontal lobe injuries are associated with executive dysfunction, but it is unclear how these injuries relate to corticostriatal interactions that are known to play an important role in behavioural control. We hypothesized that executive dysfunction after traumatic brain injury would be associated with abnormal corticostriatal interactions, a question that has not previously been investigated. We used structural and functional MRI measures of connectivity to investigate this. Corticostriatal functional connectivity in healthy individuals was initially defined using a data-driven approach. A constrained independent component analysis approach was applied in 100 healthy adult dataset from the Human Connectome Project. Diffusion tractography was also performed to generate white matter tracts. The output of this analysis was used to compare corticostriatal functional connectivity and structural integrity between groups of 42 patients with traumatic brain injury and 21 age-matched controls. Subdivisions of the caudate and putamen had distinct patterns of functional connectivity. Traumatic brain injury patients showed disruption to functional connectivity between the caudate and a distributed set of cortical regions, including the anterior cingulate cortex. Cognitive impairments in the patients were mainly seen in processing speed and executive function, as well as increased levels of apathy and fatigue. Abnormalities of caudate functional connectivity correlated with these cognitive impairments, with reductions in right caudate connectivity associated with increased executive dysfunction, information processing speed and memory impairment. Structural connectivity, measured using diffusion tensor imaging between the caudate and anterior cingulate cortex was impaired and this also correlated with measures of executive dysfunction. We show for the first time that altered subcortical connectivity is associated with large-scale network disruption in traumatic brain injury and that this disruption is related to the cognitive impairments seen in these patients.

Patients with in-situ metallic coils and Amplatzer vascular plugs used to treat pulmonary arteriovenous malformations since 1984 can safely undergo magnetic resonance imaging

Objective:

To examine the MRI safety of metallic coils and Amplatzer vascular plugs. Currently, concern regarding MR safety of devices used to treat pulmonary arteriovenous malformations (PAVMs) causes delays in performing emergency MRI in patients presenting with acute neurological symptoms.

Methods:

A retrospective audit was performed on all patients who underwent PAVM embolization at Hammersmith Hospital, London UK between 1984 and 2017. Outcomes of all MRI studies performed at our institution were recorded. In addition, known outcomes of all known MRI studies performed on patients treated with the earliest steel coils (1984–1995) were recorded.

Results:

At our institution, 20 patients underwent 1.5 T MRI after the insertion of 100 steel coils (15.5 – 28.6, median 22 years later), 140 coils designated MR-conditional (0.42 – 12.7, median 9.3 years later), and 54 MRI-conditional Amplatzer vascular plugs (0.17 – 8.0, median 0.75 years later), many in combination. The majority of scans were for cerebral indications, but other body regions scanned included spinal, thoracic, and pelvic regions. No adverse events were reported. Similarly, there were no adverse events in any MR scan known to have been performed in other institutions in seven further patients treated with the earliest steel coils (1984–1995). Again, the majority of scans were for cerebral indications.

Conclusion:

The findings demonstrate MR safety at 1.5 T of all PAVM embolization devices inserted in a main UK centre since inception in 1984.

Advances in knowledge:

MRI of patients who have had PAVMs treated by embolization can be implemented without contacting specialist pulmonary arteriovenous malformation treatment centres for approval.

Increased brain age in adults with Prader-Willi syndrome

Prader-Willi syndrome (PWS) is the most common genetic obesity syndrome, with associated learning difficulties, neuroendocrine deficits, and behavioural and psychiatric problems. As the life expectancy of individuals with PWS increases, there is concern that alterations in brain structure associated with the syndrome, as a direct result of absent expression of PWS genes, and its metabolic complications and hormonal deficits, might cause early onset of physiological and brain aging. In this study, a machine learning approach was used to predict brain age based on grey matter (GM) and white matter (WM) maps derived from structural neuroimaging data using T1-weighted magnetic resonance imaging (MRI) scans. Brain-predicted age difference (brain-PAD) scores, calculated as the difference between chronological age and brain-predicted age, are designed to reflect deviations from healthy brain aging, with higher brain-PAD scores indicating premature aging. Two separate adult cohorts underwent brain-predicted age calculation. The main cohort consisted of adults with PWS (n = 20; age mean 23.1 years, range 19.8-27.7; 70.0% male; body mass index (BMI) mean 30.1 kg/m2, 21.5-47.7; n = 19 paternal chromosome 15q11-13 deletion) and age- and sex-matched controls (n = 40; age 22.9 years, 19.6-29.0; 65.0% male; BMI 24.1 kg/m2, 19.2-34.2) adults (BMI PWS vs. control P = .002). Brain-PAD was significantly greater in PWS than controls (effect size mean ± SEM +7.24 ± 2.20 years [95% CI 2.83, 11.63], P = .002). Brain-PAD remained significantly greater in PWS than controls when restricting analysis to a sub-cohort matched for BMI consisting of n = 15 with PWS with BMI range 21.5-33.7 kg/m2, and n = 29 controls with BMI 21.7-34.2 kg/m2 (effect size +5.51 ± 2.56 years [95% CI 3.44, 10.38], P = .037). In the PWS group, brain-PAD scores were not associated with intelligence quotient (IQ), use of hormonal and psychotropic medications, nor severity of repetitive or disruptive behaviours. A 24.5 year old man (BMI 36.9 kg/m2) with PWS from a SNORD116 microdeletion also had increased brain PAD of 12.87 years, compared to 0.84 ± 6.52 years in a second control adult cohort (n = 95; age mean 34.0 years, range 19.9-55.5; 38.9% male; BMI 28.7 kg/m2, 19.1-43.1). This increase in brain-PAD in adults with PWS indicates abnormal brain structure that may reflect premature brain aging or abnormal brain development. The similar finding in a rare patient with a SNORD116 microdeletion implicates a potential causative role for this PWS region gene cluster in the structural brain abnormalities associated primarily with the syndrome and/or its complications. Further longitudinal neuroimaging studies are needed to clarify the natural history of this increase in brain age in PWS, its relationship with obesity, and whether similar findings are seen in those with PWS from maternal uniparental disomy.

Uptake and radiological findings of screening cerebral magnetic resonance scans in patients with hereditary haemorrhagic telangiectasia

Hereditary haemorrhagic telangiectasia (HHT) results in arteriovenous malformations (AVMs), most commonly in the lungs, liver and brain. Discussion of cerebral vascular malformations is an important element of patient management. The current study objectives were to examine uptake and results of screening cerebral magnetic resonance (MR) scans, excluding symptomatic patients requiring neurological investigations. The remaining non-symptomatic individuals received formal pretest counselling that differed according to family history. For the 603 patients with no neurological symptoms of concern, screening scan uptake was higher after publication of the ARUBA trial. Patients with a family history of cerebral haemorrhage were 4 to 14-fold more likely to have a screening scan than patients with no such family history. For patients without neurological symptoms suggesting cerebral AVMs, none of the 59 screening scans performed at our institution demonstrated a cerebral AVM. Four scans (6.8%) demonstrated small aneurysms. The most common abnormality was cerebral infarction (20/59, 33.9%), predominantly identified in patients with pulmonary AVMs. Of 29 pulmonary AVM patients with no previous history of clinical stroke, 16 (55.2%) had between one and five silent infarcts. For HHT patients with pulmonary AVMs, the most frequently affected sites were the cerebellum (40%) and thalamus (14.3%), and the age-adjusted odds ratio for an infarct was 21.6 (95% confidence intervals 3.7, 126), p = 0.001. We concluded that for cerebral screening programmes in HHT, the findings support informed patient choice incorporating understanding that cerebral AVMs are rare in non-symptomatic HHT patients, but that screening scans commonly detect silent cerebral infarction due to pulmonary AVMs.

Relationships between the integrity and function of lumbar nerve roots as assessed by diffusion tensor imaging and neurophysiology

Purpose

Diffusion tensor imaging (DTI) has shown promise in the measurement of peripheral nerve integrity, although the optimal way to apply the technique for the study of lumbar spinal nerves is unclear. The aims of this study are to use an improved DTI acquisition to investigate lumbar nerve root integrity and correlate this with functional measures using neurophysiology.

Methods

Twenty healthy volunteers underwent 3 T DTI of the L5/S1 area. Regions of interest were applied to L5 and S1 nerve roots, and DTI metrics (fractional anisotropy, mean, axial and radial diffusivity) were derived. Neurophysiological measures were obtained from muscles innervated by L5/S1 nerves; these included the slope of motor-evoked potential input-output curves, F-wave latency, maximal motor response, and central and peripheral motor conduction times.

Results

DTI metrics were similar between the left and right sides and between vertebral levels. Conversely, significant differences in DTI measures were seen along the course of the nerves. Regression analyses revealed that DTI metrics of the L5 nerve correlated with neurophysiological measures from the muscle innervated by it.

Conclusion

The current findings suggest that DTI has the potential to be used for assessing lumbar spinal nerve integrity and that parameters derived from DTI provide quantitative information which reflects their function.

Brain iron chelation by deferiprone in a phase 2 randomised double-blinded placebo controlled clinical trial in Parkinson's disease

Parkinson's disease (PD) is associated with increased iron levels in the substantia nigra (SNc). This study evaluated whether the iron chelator, deferiprone, is well tolerated, able to chelate iron from various brain regions and improve PD symptomology. In a randomised double-blind, placebo controlled trial, 22 early onset PD patients, were administered deferiprone, 10 or 15 mg/kg BID or placebo, for 6 months. Patients were evaluated for PD severity, cognitive function, depression rating and quality of life. Iron concentrations were assessed in the substantia nigra (SNc), dentate and caudate nucleus, red nucleus, putamen and globus pallidus by T2* MRI at baseline and after 3 and 6 months of treatment. Deferiprone therapy was well tolerated and was associated with a reduced dentate and caudate nucleus iron content compared to placebo. Reductions in iron content of the SNc occurred in only 3 patients, with no changes being detected in the putamen or globus pallidus. Although 30 mg/kg deferiprone treated patients showed a trend for improvement in motor-UPDRS scores and quality of life, this did not reach significance. Cognitive function and mood were not adversely affected by deferiprone therapy. Such data supports more extensive clinical trials into the potential benefits of iron chelation in PD.

Disconnection between the default mode network and medial temporal lobes in post-traumatic amnesia

See Bigler (doi:10.1093/aww277) for a scientific commentary on this article.

Post-traumatic amnesia is very common immediately after traumatic brain injury. It is characterized by a confused, agitated state and a pronounced inability to encode new memories and sustain attention. Clinically, post-traumatic amnesia is an important predictor of functional outcome. However, despite its prevalence and functional importance, the pathophysiology of post-traumatic amnesia is not understood. Memory processing relies on limbic structures such as the hippocampus, parahippocampus and parts of the cingulate cortex. These structures are connected within an intrinsic connectivity network, the default mode network. Interactions within the default mode network can be assessed using resting state functional magnetic resonance imaging, which can be acquired in confused patients unable to perform tasks in the scanner. Here we used this approach to test the hypothesis that the mnemonic symptoms of post-traumatic amnesia are caused by functional disconnection within the default mode network. We assessed whether the hippocampus and parahippocampus showed evidence of transient disconnection from cortical brain regions involved in memory processing. Nineteen patients with traumatic brain injury were classified into post-traumatic amnesia and traumatic brain injury control groups, based on their performance on a paired associates learning task. Cognitive function was also assessed with a detailed neuropsychological test battery. Functional interactions between brain regions were investigated using resting-state functional magnetic resonance imaging. Together with impairments in associative memory, patients in post-traumatic amnesia demonstrated impairments in information processing speed and spatial working memory. Patients in post-traumatic amnesia showed abnormal functional connectivity between the parahippocampal gyrus and posterior cingulate cortex. The strength of this functional connection correlated with both associative memory and information processing speed and normalized when these functions improved. We have previously shown abnormally high posterior cingulate cortex connectivity in the chronic phase after traumatic brain injury, and this abnormality was also observed in patients with post-traumatic amnesia. Patients with post-traumatic amnesia showed evidence of widespread traumatic axonal injury measured using diffusion magnetic resonance imaging. This change was more marked within the cingulum bundle, the tract connecting the parahippocampal gyrus to the posterior cingulate cortex. These findings provide novel insights into the pathophysiology of post-traumatic amnesia and evidence that memory impairment acutely after traumatic brain injury results from altered parahippocampal functional connectivity, perhaps secondary to the effects of axonal injury on white matter tracts connecting limbic structures involved in memory processing.

Acute neuromedical and neurosurgical admissions: Standard and ultrafast MR imaging of the brain compared with cranial CT

Purpose: To evaluate the role of standard and ultrafast MR brain imaging and compare the information with CT.

Material and Methods: This was a prospective study of 114 patients with acute neurological symptoms and signs. CT brain examinations consisted of axial non-enhanced images. MR imaging consisted of standard spin-echo/fast spin-echo sequences and a series of rapid techniques including echoplanar and single shot fast spin-echo sequences.

Results: Using standard MR methods, 41% of the patients had all five sequences of good technical quality, while using ultrafast methods 81% of the patients had good technical quality examinations in all five sequences. In 3% of the cases, ischaemic stroke was incorrectly reported on CT. In 24% of the cases, MR gave extra diagnostic information not reported on CT and in a further 8%, one neuroradiologist reported the abnormality in agreement with the MR, whilst the other neuroradiologist reported the CT as normal. In 2 cases, subarachnoid haemorrhage was missed on MR. Subarachnoid haemorrhage was not shown on the ultrafast sequences.

Conclusion: MR can be used to image acute neurological admissions with a high success rate, particularly using ultrafast methods. In many cases, MR provided extra information of direct clinical relevance not shown on CT.

Hypertrophic pachymeningitis with sarcoidosis: a rare cause of craniocervical compression

We describe a case of a 58-year-old woman with a suspected dural tumour. She presented with progressive pyramidal weakness. MRI confirmed compression of the medulla oblongata and spinal cord at the level of C1-3. The localised dural mass lesion homogenously enhanced on T1 MRI and was considered most likely to be a meningioma. Incidentally, CT scan of the chest revealed peribronchial soft tissue thickening, suggestive of pulmonary sarcoidosis. Owing to the progressive nature of her weakness, she had a posterior occipitocervical decompression with a C1-3 laminectomy and resection of the thickened dura. Histology showed densely collagenous tissue with scanty psammoma bodies and multinucleate giant cells, consistent with hypertrophic pachymeningitis (HP)-a rare, chronic inflammatory condition, characterised by thickening and fibrosis of the dura. This case demonstrates that masses in the craniocervical junction can be varied in pathology and when there is evidence of systemic inflammation, HP should be considered.

Recurrent headaches: a case of neurological Behçet's disease

A 48-year-old black male, of Nigerian heritage, presented with a 24-hour history of frontal headache of gradual onset. The headache characteristic was migranous, being described as throbbing in nature and located to the right frontal area with associated blurring of vision. Although similar to prior frequent headaches, there was now increasing unsteadiness on walking. Diagnosed 10 years earlier with Behçet's disease, the initial presentation was with oral and genital ulceration. Recurrent episodes of headache caused by neurological flare-ups resulted in a stroke at the age of 46 years. This previous stroke was ischaemic in character with involvement of the brainstem, pons, midbrain and right cerebral peduncle with extension into the right internal capsule. Surveillance brain imaging (computed tomographic and magnetic resonance imaging with venography) 10 months earlier showed brainstem disease activity (Figure 1a) with disease quiescence a month later (Figure 1b) following an escalation of immunosuppressant therapy. Regular medications comprised prednisolone 10 mg (however, regular recurrences had resulted in him taking doses of between 20 and 30 mg/day of prednisolone for most of the past 24 months) and azathioprine 150 mg daily, aspirin 75 mg daily, one adcal D3 twice daily with weekly alendronic acid, and omeprazole 20 mg daily. For headache he took topiramate 25 mg daily and for depression mirtazepine 15 mg daily. The patient was also addicted to a high level of cannabis use which he was reluctant to stop as he felt it helped his symptoms. On examination he was apyrexial and cardiovascularly stable. Neurological examination revealed a residual horizontal nystagmus to the right on lateral gaze, mild left hemiparesis with moderate spasticity, in addition to dysarthria and dysphonia from his prior stroke. A new feature was an exacerbation of gait unsteadiness. Blood tests were unremarkable and specifically the erythrocyte sedimentation rate was normal at 2 mm/hr (normal range 0-10 mm/hr). Immediate therapy involved an increase in steroid dosage to methyl prednisolone 1 g/day for 3 days, followed by oral prednisolone 60 mg daily. This was maintained for 2 weeks and then reduced by 10 mg/week to a maintenance dose of 10 mg/day. Magnetic resonance scanning revealed a marked increase in inflammation of the brainstem (Figure 1c). The patient required physiotherapy and occupational therapy with psychiatric input and was able to leave the hospital after 29 days.

Pituitary dysfunction after blast traumatic brain injury: The UK BIOSAP study

OBJECTIVE

Pituitary dysfunction is a recognized consequence of traumatic brain injury (TBI) that causes cognitive, psychological, and metabolic impairment. Hormone replacement offers a therapeutic opportunity. Blast TBI (bTBI) from improvised explosive devices is commonly seen in soldiers returning from recent conflicts. We investigated: (1) the prevalence and consequences of pituitary dysfunction following moderate to severe bTBI and (2) whether it is associated with particular patterns of brain injury.

METHODS

Nineteen male soldiers with moderate to severe bTBI (median age = 28.3 years) and 39 male controls with moderate to severe nonblast TBI (nbTBI; median age = 32.3 years) underwent full dynamic endocrine assessment between 2 and 48 months after injury. In addition, soldiers had structural brain magnetic resonance imaging, including diffusion tensor imaging (DTI), and cognitive assessment.

RESULTS

Six of 19 (32.0%) soldiers with bTBI, but only 1 of 39 (2.6%) nbTBI controls, had anterior pituitary dysfunction (p = 0.004). Two soldiers had hyperprolactinemia, 2 had growth hormone (GH) deficiency, 1 had adrenocorticotropic hormone (ACTH) deficiency, and 1 had combined GH/ACTH/gonadotrophin deficiency. DTI measures of white matter structure showed greater traumatic axonal injury in the cerebellum and corpus callosum in those soldiers with pituitary dysfunction than in those without. Soldiers with pituitary dysfunction after bTBI also had a higher prevalence of skull/facial fractures and worse cognitive function. Four soldiers (21.1%) commenced hormone replacement(s) for hypopituitarism.

INTERPRETATION

We reveal a high prevalence of anterior pituitary dysfunction in soldiers suffering moderate to severe bTBI, which was more frequent than in a matched group of civilian moderate to severe nbTBI subjects. We recommend that all patients with moderate to severe bTBI should routinely have comprehensive assessment of endocrine function.

Extracranial-intracranial bypass of the bilateral anterior cerebral circulation using a thoracodorsal axis artery-graft

Bilateral extracranial-intracranial (EC-IC) bypass-grafting of the cerebral circulation is uncommon. We report a case of anterior cerebral artery EC-IC bypass using the thoracodorsal axis artery-graft. The bifurcation of the thoracodorsal axis allows bypass of both anterior hemispheres, while matching appropriate small-vessel dimensions.

Auditory cortical function during verbal episodic memory encoding in Alzheimer's disease

OBJECTIVE

Episodic memory encoding of a verbal message depends upon initial registration, which requires sustained auditory attention followed by deep semantic processing of the message. Motivated by previous data demonstrating modulation of auditory cortical activity during sustained attention to auditory stimuli, we investigated the response of the human auditory cortex during encoding of sentences to episodic memory. Subsequently, we investigated this response in patients with mild cognitive impairment (MCI) and probable Alzheimer's disease (pAD).

METHODS

Using functional magnetic resonance imaging, 31 healthy participants were studied. The response in 18 MCI and 18 pAD patients was then determined, and compared to 18 matched healthy controls. Subjects heard factual sentences, and subsequent retrieval performance indicated successful registration and episodic encoding.

RESULTS

The healthy subjects demonstrated that suppression of auditory cortical responses was related to greater success in encoding heard sentences; and that this was also associated with greater activity in the semantic system. In contrast, there was reduced auditory cortical suppression in patients with MCI, and absence of suppression in pAD. Administration of a central cholinesterase inhibitor (ChI) partially restored the suppression in patients with pAD, and this was associated with an improvement in verbal memory.

INTERPRETATION

Verbal episodic memory impairment in AD is associated with altered auditory cortical function, reversible with a ChI. Although these results may indicate the direct influence of pathology in auditory cortex, they are also likely to indicate a partially reversible impairment of feedback from neocortical systems responsible for sustained attention and semantic processing.

3-(2-Chloro-3-hy-droxy-4-meth-oxy-phen-yl)-1-(4,5-dimeth-oxy-2-methyl-phen-yl)prop-2-en-1-one

The title compound, C(19)H(19)ClO(5), is a chloro derivative of a biologically significant chalcone family. The mean plane of the two substituted benzene rings are twisted by 55.33 (8)° with respect to each other. An intra-molecular C-H⋯Cl hydrogen bond generates an S(5) graph-set motif. In the crystal, a bifurcated O-H⋯(O,O) hydrogen bond leads to an R(1) (2)(5) graph-set motif and to the formation of zigzag chains propagating along the c-axis direction. A weak π-π inter-action involving the methyl-phenyl rings [centroid-centroid distance = 3.8185 (10) Å] and C-H⋯π inter-actions also occur.

The prevalence of traumatic dental injuries to permanent anterior teeth and its relation with predisposing risk factors among 8-13 years school children of Vadodara city: an epidemiological study

BACKGROUND AND OBJECTIVE

dental trauma is an irreversible pathology that after occurrence is characterized by life-long debilitating effects. The objectives of this study were to measure the prevalence of anterior teeth fracture and their association with predisposing factors such as lip coverage, molar relationship, overjet, and variables such as age, sex, cause, and place of trauma.

MATERIALS AND METHODS

an epidemiological cross-sectional study was carried out among 3708 school children aged 8-13 years in the Vadodara city. All children completed a questionnaire related to history of trauma to their anterior teeth after which they were examined for lip competence, Angle's molar relationship amount of overjet and nature of trauma sustained. The results were statistically analyzed using the prevalence test, Chi-square test, and Mantel-Haenszel Common Odds Ratio.

RESULTS

the prevalence of traumatic injuries was 8.79% and the ratio of boys: girl's was 1.28:1. Inadequate lip coverage group sustained about five times more injuries than the adequate lip coverage group (P = 0.000, OR= 5.407). The maximum traumatic injuries were seen in children having Angle Class II Div 1 molar relationship and/or overjet greater than 5.5 mm and was statistically significant (P<0.05). Maximum number of injuries occurred at 9 years of age. The most predominant injuries were enamel fractures, the most common place for occurrence was home and fall against object, the most frequent cause.

CONCLUSION

the prevalence of dental injuries in the Vadodara city is high and it has a great potential to be considered as an emerging public health problem.

Making a jigsaw puzzle in 10 minutes: is case management feasible in general practice?

Background Case management has been advocated as a method of optimising the care of patients with complex problems and reducing inappropriate use of hospital services, but its impact to date has been limited. It is not known whether case management earlier in the development of complex problems will be more effective. Aim To develop a case management protocol usable in general practice. Design Co-designed by practitioners using a technology development approach. Setting General practices and community nursing teams in one primary care trust (PCT). Method Nominal group techniques applied to six multidisciplinary workshops held over nine months, in order to design and refine a case management protocol. Then field testing of the protocol with selected patients in four practices. Results A modular case management protocol has been designed that can be used in routine practice and completed over successive consultations. The protocol asks the practitioner and patient about their different perspectives on need, and about mental health, social care needs, nutritional status, vision and hearing, bone fragility, pain, continence and where appropriate end-of-life plans. An electronic version can be partially populated automatically, from the existing medical record. Field testing suggests that a paper version can also be used as a patient-held record for other professionals to use. Conclusion This study has created a model of case management for general practice that appears to be useable in general practice. A wider feasibility study is now needed to test uptake of the protocol by practices.

Trimethoprim related Hyperkalaemia in a patient with Renal Tubular Acidosis Type 4

Hyperkalaemia is a common, treatable, medical emergency, often with an iatrogenic cause. This case illustrates the vulnerability of patients with pre-existing renal tubular acidosis type 4 to medications that further inhibit renin-aldosterone action. The case also illustrates the danger of keeping entirely separate case notes between different hospital disciplines.

Abciximab in patients with ruptured intracranial aneurysms

BACKGROUND AND PURPOSE

Experience with intravenous abciximab to manage thromboembolism during treatment of ruptured intracranial aneurysms is limited. We present our experience in 13 patients.

METHODS

We retrospectively reviewed all patients with thromboembolic complications during endovascular management of ruptured intracranial aneurysms. Thromboembolic complications were treated with intravenous abciximab. We recorded patient and aneurysm demographics, aneurysm occlusion, drug therapy, complications, and outcomes.

RESULTS

World Federation of Neurological Surgeons Grades were 1 or 2 in 11 patients (85%). Median time from diagnostic angiography to treatment was 1 day. Ten (77%) aneurysms involved the anterior or posterior communicating artery, and one each occurred in the posterior inferior cerebellar artery, middle cerebral artery, and basilar regions. Eleven aneurysms were <10 mm. Five were incompletely occluded (0%-90% treated) at the time of the complication. Thromboembolic complications were at the coil-ball/parent-artery interface in nine patients (69%). Two were associated with coil-loop prolapse; one was prophylactically treated without evidence of thromboembolism. Five patients (38%) had distal complications; one also had a proximal thrombus. All patients received an intravenous bolus of abciximab (5-10 mg in 92%) without infusion. Postprocedural recanalization was complete in eight (62%) and partial in four (31%). Eleven patients (85%) had a Glasgow Outcome Scale score of 1 at 3 months. One had a poor outcome (GOS4). One died following additional coiling after abciximab administration, though this intervention was uneventful in three others.

CONCLUSION

Abciximab completely or partially treated thromboembolic complications arising during coiling of ruptured aneurysms. Further coiling should be performed with extreme caution and needs to be decided on a patient-by-patient basis.

Erythrodermic syringotropic cutaneous T-cell lymphoma

Syringotropic cutaneous T-cell lymphoma (CTCL) is a rare localized variant of CTCL, characterized histologically by eccrine gland and ductal hyperplasia surrounded by a dense syringotropic lymphocytic infiltrate. Previously reported only in men, we describe the first woman with syringotropic CTCL. Unusually, she presented with erythroderma, cutaneous nodules, poikilodermatous patches, widespread alopecia and lymphadenopathy.

Rhodium-catalyzed regioselective olefin hydrophosphorylation

Parameters influencing the selectivity of the (PPh(3))(3)RhCl-catalyzed hydrophosphorylation of olefins and enynes are described. The reaction between differentiated dienes was shown to be highly responsive to olefin substitution. The trimethylsilyl group effectively reversed the normal preference for hydrophosphorylation of an alkyne over an alkene. [reaction: see text]

Phase I trial of lobradimil (RMP-7) and carboplatin in children with brain tumors

PURPOSE

To determine the maximum tolerated dose (MTD), the incidence and severity of toxicities, and the pharmacokinetics of lobradimil administered intravenously over 10 min in combination with carboplatin in children with refractory brain tumors.

METHODS

A group of 25 children with primary brain tumors received carboplatin and lobradimil on two consecutive days every 28 days. The 10-min lobradimil infusion began 5 min before the end of the carboplatin infusion. Four lobradimil dose levels (100, 300, 450 and 600 ng/kg ideal body weight, IBW) were studied in cohorts of 4 to 13 patients. Carboplatin was adaptively dosed based on the glomerular filtration rate to achieve a target plasma area under the concentration-time curve (AUC) of 7.0 mg min/ml per course (5.0 mg min/ml for patients who had previously received craniospinal radiation or myeloablative chemotherapy).

RESULTS

Lobradimil toxicity was immediate, tolerable and rapidly reversible. The most frequent toxicities were hypotension, flushing, headache and gastrointestinal complaints. One patient on the 600 ng/kg dose level had a seizure during the lobradimil infusion. The incidence and severity of lobradimil toxicities were not dose-related and the lobradimil dose was not escalated beyond the 600 ng/kg IBW dose level. Two patients had partial responses and ten patients had stable disease. Myelosuppression (thrombocytopenia more prominent than neutropenia) was the primary toxicity attributed to carboplatin. Lobradimil pharmacokinetics were characterized by rapid clearance from the plasma compartment and substantial interpatient variability.

CONCLUSIONS

The combination of carboplatin and lobradimil is safe and tolerable. An MTD for lobradimil was not defined because toxicity was not dose-related. The recommended pediatric phase II dose of lobradimil is 600 ng/kg IBW.

Multimodality MR imaging depiction of hemodynamic changes and cerebral ischemia in subarachnoid hemorrhage

BACKGROUND AND PURPOSE

Subarachnoid hemorrhage (SAH) is a common and serious neurologic emergent condition. We tested the hypothesis that multimodality MR imaging depicts changes in cerebral blood flow SAH, before any surgical or endovascular intervention, and that the frequency of these changes increases with time after ictus.

METHODS

We prospectively examined 37 patients with suspected SAH and three with symptoms of acute stroke but who subsequently had SAH. Routine CT and multimodality MR imaging were performed within 18 h of presentation. Standard MR imaging, diffusion-weighted MR imaging, time-of-flight MR angiography, and dynamic first-pass gadolinium-enhanced MR perfusion imaging were performed. Images were reviewed for abnormalities in cerebral blood flow, ischemia, and infarction. Nine patients did not have SAH at CT and CSF investigations. Of 31 patients with proved SAH, 13 were examined during the acute stage (within 4 d of ictus) and 18, during the subacute stage (4-14 d after ictus).

RESULTS

MR imaging showed alteration in cerebral blood flow parameters in 16 of 31 patients before surgery or endovascular treatment. The frequency of blood flow changes and associated complications increased with worsening clinical grade and increasing time after ictus.

CONCLUSION

Multimodality MR imaging provides information not available from CT in patients with SAH. MR imaging shows oligemic and ischemic areas in SAH before surgery or endovascular treatment. MR imaging is a simple noninvasive method of assessing cerebral blood flow and its complications in SAH. It can be performed in a clinical environment.

Imaging infection with LeuTech

LeuTech is a 99Tcm labelled, anti-CD15, IgM, murine monoclonal antibody shown to have high affinity (Kd = 10(-11) M) for CD15 receptors (5.1 x 10(5)/cell) expressed on human neutrophils. LeuTech was injected directly, intravenously, and its efficacy in imaging infection in 46 consecutive patients was determined. Human anti-mouse antibody (HAMA) response was examined in 30 normal volunteers using a standard LeuTech dose reconstituted with decayed 99Tcm solution. There were 38 true positive, six true negative, and two false negative scans. Of the 38 positive images, 33 (92%) were positive within 10 min after injection of LeuTech. LeuTech accuracy in this group of patients was 96%, sensitivity 95%, specificity 100%, positive predictive value (PPV) 100%, and negative predictive value (NPV) 75%. No elevation of the HAMA titre was observed in any of the 30 normal volunteers and no adverse reaction was noted in any patient. LeuTech is a highly promising agent for rapid imaging of infectious foci.

Spontaneous obliteration of pial arteriovenous malformations: a review of 27 cases

BACKGROUND AND PURPOSE

Brain arteriovenous malformations (AVMs) occur in approximately 0.14% of the population. The most common presentations are hemorrhage (50%) and seizures (25%). Although they are congenital abnormalities, their angioarchitecture may vary over time. A rare but well-recognized phenomenon of AVMs is that of spontaneous obliteration. It is not known what factors predispose to spontaneous obliteration. The purpose of our study was to determine whether spontaneous thrombosis of AVMs can be predicted by their angioarchitecture and whether there is any risk of recurrence once obliteration has occurred.

METHODS

We retrospectively reviewed the angiographic and cross-sectional imaging data amassed over an 18-year period, including follow-up imaging studies and mail surveys of referring and family physicians. A control group was obtained from contemporaneous AVMs of a similar size.

RESULTS

We identified 28 cases of spontaneous obliteration in a series of 2162 patients. The mean time between initial diagnostic angiography and angiographic obliteration was 10 months, during which time there was no intervention and no history of repeat hemorrhage; nor had hemorrhage recurred during the follow-up period (mean, 53 months). Most of the AVMs were deep (22/27) with only one draining vein (21/27) and few feeding arteries. In more than half the cases (15/27) drainage was exclusively into the superficial venous system.

CONCLUSION

Spontaneous obliteration is rare (1.3%). Common features include hemorrhagic presentation and few arterial feeding vessels. Although we found no instance of repeat hemorrhage during the follow-up period, AVMs can recanalize, and follow-up is therefore recommended.

Muscle paralysis produced by botulinum toxin type A injection in treated torticollis patients compared with toxin naive individuals

We sought to determine whether the response to varying doses of botulinum toxin type A (BTX-A) injected in BTX-A-treated torticollis patients differed from the same injections given in toxin-naive individuals. We have developed a technique to objectively measure muscle weakness resulting from BTX injections in humans and have validated the technique in those not previously treated with BTX. We now examine BTX-A-treated torticollis patients to see if their response to BTX-A injection is similar to that of toxin-naive individuals. We injected 11 torticollis patients who had been receiving BTX-A injections with a standard 5-mouse unit (mu) dose into one extensor digitorum brevis (EDB) muscle and a varying dose into the other EDB, measuring muscle paralysis 2 weeks after the injection. Nine of the 11 patients were clinical and electrophysiologic responders. Two patients were non-responders. In the 9 responding patients the dose response curve to increasing doses of BTX-A was very similar to that seen in toxin-naive individuals. The mean muscle paralysis from the standard 5 mu dose was also similar to that previously reported in toxin-naive individuals. Torticollis patients who continue to respond clinically to BTX-A injections demonstrate essentially the same degree of muscle paralysis from the EDB injections as do subjects who have never been exposed to BTX-A.

Riedel's lobe of the liver: fact or fiction?

Riedel's lobe should be considered in all patients undergoing cross-sectional imaging. It may harbor a lesion that might not be demonstrated unless the most inferior aspect of the liver is imaged. We have tried to identify the prevalence of Riedel's lobe in a series of patients with normal abdominopelvic computed tomographic (CT) findings. We reviewed the digital CT data of 105 patients, ages 20-89 years, to define the position of the liver in relation to the costal margin and the iliac crest. There were no significant differences in the prevalence of Riedel's lobe between sexes. The proportion of individuals in whom the most caudal margin of the liver was inferior to the most caudal costal margin was age-dependent and increased to 65% in the 50-59 age group. The craniocaudal dimension of the liver decreased with age (P < 0.02). Riedel's lobe appears to be a common variant of normal anatomy, its prevalence being dependent on age-related changes in liver size and skeletal shape.

Effect of P-glycoprotein modulation with cyclosporin A on cerebrospinal fluid penetration of doxorubicin in non-human primates

PURPOSE

P-glycoprotein (Pgp) is a transmembrane drug efflux pump that is expressed in multidrug-resistant cancer cells and in a variety of normal tissues, including brain capillary endothelial cells which comprise the blood-brain barrier. We studied the effects of the Pgp inhibitor, cyclosporin A (CsA), on the cerebrospinal fluid (CSF) penetration of the Pgp substrate, doxorubicin, in non-human primates.

METHODS

The animals received doxorubicin alone (2.0 mg/kg i.v. over 60 min) or doxorubicin (1 mg/kg i.v. over 60 min) and CsA (loading dose 4.0 mg/kg i.v. over 2 h, followed by continuous infusion of 12 mg/kg per day over 48 h). Plasma and CSF were collected over 48 h and the doxorubicin concentration was measured by reverse-phase high-pressure liquid chromatography (HPLC) with fluorescence detection (detection limit 5 nM). A two-compartment model was fitted to the plasma concentration-time data.

RESULTS

Pgp was demonstrated to be present in the epithelium of the choroid plexus by immunohistochemical methods, indicating that CSF drug penetration could be used as a surrogate for blood-brain barrier penetration. Steady state whole blood CsA concentrations, which were measured with a fluorescence-polarization immunoassay (TDX) that detects both CsA and its metabolites, ranged from 551-1315 microg/l at 24 h. The clearance of doxorubicin in four animals was reduced by 34%, 38%, 45% and 49% when given with CsA. The doxorubicin concentration in the CSF was <5 nM in all animals, both after doxorubicin alone and doxorubicin with CsA.

CONCLUSIONS

The Pgp inhibitor, CsA, at a concentration that alters systemic clearance of doxorubicin, does not appear to significantly increase the CSF penetration of doxorubicin.

Endarterectomy of an Occluded ICA: Short Segment Occlusion with Distal Patency Maintained by an Aberrant Ascending Pharyngeal Artery

SUMMARY

The authors report a case in which an anomalous ascending pharyngeal artery maintained patency of the internal carotid artery beyond an occlusion. The patient presented with ipsilateral transient ischaemic attacks and was found to have an internal carotid artery occlusion on Doppler ultrasound. Subsequent angiography demonstrated retrograde flow in the ipsilateral APA, perfused by pharyngeal anastomoses from the contralateral APA with slow antegrade flow in the ipsilateral ICA distal to the occlusion. Carotid endarterectomy resulted in abolition of the TIA's.

Subclavian and internal jugular veins at Doppler US: abnormal cardiac pulsatility and respiratory phasicity as a predictor of complete central occlusion

In 21 consecutive patients, the authors analyzed changes in venous Doppler waveforms of damped or diminished cardiac pulsatility and respiratory phasicity. Each patient was suspected of having upper limb venous thrombosis, but thrombus was not visible at gray-scale ultrasonography (US) in the subclavian and brachiocephalic veins. US findings were compared with phlebographic findings. The results show that US can be used to establish the presence or absence of thrombosis in the distal portion of the brachiocephalic or subclavian veins, which are inaccessible to direct insonation.

Technique for reduction of bile peritonitis after T-tube removal in liver transplant patients

PURPOSE

The purpose of this work was to evaluate the incidence of bile peritonitis following T-tube removal in liver transplant patients as a function of the method of T-tube removal. Removal at the bedside was compared to removal in the interventional radiology department with subsequent placement of a temporary drainage catheter.

MATERIALS AND METHODS

From June 1987 through July 1993, 1,105 patients underwent orthotopic liver transplantation at the UCLA Medical Center. Three hundred patients were randomly selected from this group and their charts were reviewed. Two hundred sixty-three patients who had choledocho-choledochostomies over a T tube, and adequate documentation of the method of T-tube removal and subsequent clinical course were included in the study. Forty-one patients had their drainage catheter removed at the bedside, and 222 patients had their T-tube removed over a wire in the interventional radiology department with subsequent placement of a temporary drainage catheter.

RESULTS

Among all patients included in this study, 10.3% had bile peritonitis. Of the patients who had their T-tube removed at the bedside, 19.5% had bile peritonitis, whereas only 8.6% of the patients who had their T-tube removed in the interventional radiology department had bile peritonitis. This result is statistically significant (P < .05).

CONCLUSION

Placing a temporary drain at the time of T-tube removal in the interventional radiology department results in a significant reduction in the incidence of bile peritonitis in liver transplant patients. The procedure is relatively simple, quickly mastered, and well tolerated by patients.

Riedel's lobe of the liver: fact or fiction?

Riedel's lobe should be considered in all patients undergoing cross-sectional imaging. It may harbor a lesion that might not be demonstrated unless the most inferior aspect of the liver is imaged. We have tried to identify the prevalence of Riedel's lobe in a series of patients with normal abdominopelvic computed tomographic (CT) findings. We reviewed the digital CT data of 105 patients, ages 20-89 years, to define the position of the liver in relation to the costal margin and the iliac crest. There were no significant differences in the prevalence of Riedel's lobe between sexes. The proportion of individuals in whom the most caudal margin of the liver was inferior to the most caudal costal margin was age-dependent and increased to 65% in the 50-59 age group. The craniocaudal dimension of the liver decreased with age (P < 0.02). Riedel's lobe appears to be a common variant of normal anatomy, its prevalence being dependent on age-related changes in liver size and skeletal shape.

Riedel's lobe of the liver: fact or fiction?

Riedel's lobe should be considered in all patients undergoing cross-sectional imaging. It may harbor a lesion that might not be demonstrated unless the most inferior aspect of the liver is imaged. We have tried to identify the prevalence of Riedel's lobe in a series of patients with normal abdominopelvic computed tomographic (CT) findings. We reviewed the digital CT data of 105 patients, ages 20-89 years, to define the position of the liver in relation to the costal margin and the iliac crest. There were no significant differences in the prevalence of Riedel's lobe between sexes. The proportion of individuals in whom the most caudal margin of the liver was inferior to the most caudal costal margin was age-dependent and increased to 65% in the 50-59 age group. The craniocaudal dimension of the liver decreased with age (P < 0.02). Riedel's lobe appears to be a common variant of normal anatomy, its prevalence being dependent on age-related changes in liver size and skeletal shape.

Radiology in the management of pleural disease

This is a review of the role of radiological intervention in the pleural space. It discusses the radiological management of effusions, empyemas (including the use of fibrinolytic agents), pneumothoraces and pleural thickening.