Safety of working patterns among UK neuroradiologists: what can we learn from the aviation industry and cognitive science?

As the volume and complexity of imaging in the UK continues to rise, there is pressure on radiologists to spend increasing lengths of time reporting to cope with the growing workload. However, there is limited guidance for radiologists about structuring the working day to strike the necessary balance between achieving satisfactory reporting volume and maintaining quality and safety. We surveyed 86 neuroradiologists (receiving 59 responses), regarding time spent reporting, frequency and duration of work breaks, and break activities. Our results demonstrate that some neuroradiologists report for up to 12 h a day and for 4 h before taking a break. Mean duration of breaks is less than 15 min and these often consist of computer screen-based or cognitively demanding tasks. Many areas of medicine have looked to the aviation industry to develop improvements in safety through regulated, standardised practices. There are parallels between the work of air traffic controllers (ATCs) and radiologists. We review the legislation that controls the working hours of UK ATCs to minimise fatigue-related errors, and its scientific basis. We also consider the vigilance decrement, a concept in cognitive science which describes the reduction in performance with increasing time-on-task. We conclude that, in comparison with ATCs, work patterns among radiologists are poorly standardised and potentially dangerous. Evidence suggests that placing limits on reporting time and minimum break duration, as well as ensuring appropriate break activities, can benefit reporting quality. It is imperative that radiologists and managers heed these lessons, to improve standards and protect patients from error.

Cysticercosis and epilepsy in rural Tanzania: a community-based case-control and imaging study.

OBJECTIVE: To assess the contribution of neurocysticercosis (NCC) to the burden of epilepsy in a rural Tanzanian population. METHODS: We identified adult people with epilepsy (PWE) in a door-to-door study in an established demographic surveillance site. PWE and community controls were tested for antibodies to Taenia solium, the causative agent of NCC, and all PWE were offered a computed tomography (CT) head scan. Data on household occupancy and sanitation, pig-keeping and pork consumption were collected from PWE and controls and associations with epilepsy were assessed using chi-square or Fisher's exact tests. RESULTS: Six of 218 PWE had antibodies to T. solium (2.8%; 95% CI 0.6-4.9), compared to none of 174 controls (Fisher's exact test, P = 0.04). Lesions compatible with NCC were seen in eight of 200 CT scans (4.0%; 95% CI 1.3-6.7). A total of 176 PWE had both investigations of whom two had positive serology along with NCC-compatible lesions on CT (1.1%; 95% 0.3-4.0). No associations between epilepsy and any risk factors for NCC were identified. CONCLUSIONS: Neurocysticercosis is present in this population but at a lower prevalence than elsewhere in Tanzania and sub-Saharan Africa. Insights from low-prevalence areas may inform public health interventions designed to reduce the burden of preventable epilepsy.

EXOSC8 mutations alter mRNA metabolism and cause hypomyelination with spinal muscular atrophy and cerebellar hypoplasia.

The exosome is a multi-protein complex, required for the degradation of AU-rich element (ARE) containing messenger RNAs (mRNAs). EXOSC8 is an essential protein of the exosome core, as its depletion causes a severe growth defect in yeast. Here we show that homozygous missense mutations in EXOSC8 cause progressive and lethal neurological disease in 22 infants from three independent pedigrees. Affected individuals have cerebellar and corpus callosum hypoplasia, abnormal myelination of the central nervous system or spinal motor neuron disease. Experimental downregulation of EXOSC8 in human oligodendroglia cells and in zebrafish induce a specific increase in ARE mRNAs encoding myelin proteins, showing that the imbalanced supply of myelin proteins causes the disruption of myelin, and explaining the clinical presentation. These findings show the central role of the exosomal pathway in neurodegenerative disease.

Muscular dystrophy with large mitochondria associated with mutations in the CHKB gene in three British patients: extending the clinical and pathological phenotype.

Three patients with CHKB deficient muscular dystrophy are described which broadens the previously described phenotype. Blood smear in one patient showed Jordans anomaly (vacuolated leukocytes). Gastrointestinal features occurred in two patients and there appeared to be acute deterioration with infection/general anaesthesia. Brain imaging showed no structural changes but brain magnetic resonance proton spectroscopy (MRS) demonstrated significant reduction in choline:N-acetyl aspartate and choline:creatine ratios in keeping with a general decrease in the amount of choline and phosphocholine-based substrate. Muscle pathology showed either myopathic or dystrophic features, uneven oxidative enzyme staining, COX deficient fibres and peripherally located large mitochondria. CHKB activity was reduced in all three patients and complex 1 activity was significantly reduced in one patient.

Disease activity and cognition in rheumatoid arthritis: an open label pilot study.

INTRODUCTION: We hypothesised that fatigue in rheumatoid arthritis (RA) is related to TNF-alpha induced dysregulation of cerebral blood flow. Our objectives were to assess fatigue, cognitive function and cerebral blood flow before and after initiation of anti-TNF treatment. METHODS: In a pilot study, 15 patients initiating treatment with adalimumab were assessed for fatigue using a visual analogue scale (FACIT-F), cognitive function using a panel of psychometric tests and regional cerebral blood flow using MR perfusion imaging. RESULTS: Patients improved clinically after anti-TNF therapy in terms of DAS28 and FACIT-F. Furthermore significant improvements were documented in full scale, verbal and performance IQ following therapy. There was a non-significant trend towards reduced cerebral perfusion in both grey and white matter, and fatigue at 3 months correlated with cerebral blood flow in white (p = 0.014) and grey (p = 0.005) matter. CONCLUSIONS: We demonstrate for the first time a significant improvement in cognitive function following effective treatment of RA. Although we observed minor reductions in cerebral blood flow, and a correlation between cerebral blood flow and fatigue, a larger, controlled study would be required to affirm a causal relationship.

Prevalence of active epilepsy in rural Tanzania: a large community-based survey in an adult population.

PURPOSE: To estimate the prevalence of active epilepsy in adults in an established demographic surveillance site in rural Tanzania. To describe the clinical characteristics of epilepsy and to estimate the treatment gap in this population. METHODS: A pilot study established that a previously validated screening questionnaire was sensitive for detecting cases of epilepsy in a Kiswahili-speaking Tanzanian population. A door-to-door census of the adult population (total 103,026) used the screening questionnaire to identify possible cases of epilepsy, who were then assessed by a research doctor to establish a diagnosis of epilepsy or otherwise. The prevalence of active epilepsy in this population was estimated with age-standardisation to the WHO standard population. Seizure types and epilepsies were classified according to current recommendations of the International League Against Epilepsy. The treatment gap for epilepsy was estimated based on antiepileptic drug use as reported by cases. RESULTS: Two hundred and ninety-one cases of active epilepsy, all with convulsive seizures, were identified. The age-standardised prevalence was 2.91/1000 adults (95% CI 2.58-3.24); the crude prevalence adjusted for non-response was 3.84/1000 adults (95% CI 3.45-4.20). Focal-onset seizures accounted for 71.5% of all cases identified. The treatment gap was 68.4% (95% CI 63.0-73.7). CONCLUSIONS: This is one of the largest community-based studies of the prevalence of epilepsy in adults conducted in sub-Saharan Africa to date. We identified a lower prevalence than has previously been described in this region. The high proportion of focal onset seizures points to a large burden of acquired, and possibly preventable, epilepsy in this population. A treatment gap of 68.4% confirms that interventions to raise awareness of the treatable nature of epilepsy are warranted in this and similar populations.

Henoch-Schönlein purpura with posterior reversible encephalopathy syndrome.

We describe atypical Henoch-Schönlein purpura with posterior reversible encephalopathy syndrome in a normotensive 11-year-old girl. Her Henoch-Schönlein purpura was atypical because she initially presented with abdominal pain and vomiting and neurologic complications, rather than with the classic rash of Henoch-Schönlein Purpura. This previously healthy child was also unusual because she manifested the radiologic and clinical features of posterior reversible encephalopathy syndrome in the absence of hypertension induced by Henoch-Schönlein purpura. Her abnormal findings resolved with supportive therapy. We discuss the association of posterior reversible encephalopathy syndrome with Henoch-Schönlein purpura in three previously reported cases.

Primary care access to diagnostics: a paradigm shift.

There is increasing medico-political impetus for the provision of direct access imaging services to primary care. This is likely to have fundamental effects on the way that imaging services are organised and provided, and radiologists need to be aware of the paradigm shift that is being promoted. This commentary summarises some of the key issues arising, and has been written to complement a recent conference organised by the British Institute of Radiology.

MR imaging in Duchenne muscular dystrophy: quantification of T1-weighted signal, contrast uptake, and the effects of exercise.

PURPOSE: To quantify the differences between normal and corticosteroid-treated Duchenne muscular dystrophy (DMD) lower limb muscle using signal intensity measurements on T(1)-weighted and gadolinium contrast-enhanced images and by measurement of muscle T(2) values, and to investigate the effect of exercise. MATERIALS AND METHODS: Eleven ambulant boys with DMD were imaged at 3 Tesla (T(1)-weighted, gadolinium enhancement and T(2) measurement) before stepping exercise and again (gadolinium, T(2) measurement) 4 days later and were compared with five healthy controls imaged 4 days before and after stepping exercise. Muscle region-of-interest signal intensities were referenced to external oil and gadolinium phantoms. RESULTS: DMD thigh muscle T(2) values were significantly higher than normal values with the exception of the gracilis muscle. Eight of nine muscles studied showed a significant increase in T(1)-w signal intensity in DMD as compared to normal muscle, suggestive of increased fat infiltration in DMD muscle. In the DMD boys, an exercise effect (increased contrast enhancement) was only seen for the tibialis anterior muscle. CONCLUSION: Referenced signal intensity measurements may be used to quantify differences between dystrophic and normal muscle without T(1) mapping. Stepping exercise does not have a large impact on subsequent MR imaging of dystrophic muscle.

Lower limb radiology of distal myopathy due to the S60F myotilin mutation.

Distal myopathies are a clinically and genetically heterogenous group of disorders in which the distal limb musculature is selectively or disproportionately affected. Precisely defining specific categories is a challenge because of overlapping clinical phenotypes, making it difficult to decide which of the many known causative genes to screen in individual cases. In this study we define the distinguishing magnetic resonance imaging findings in myotilin myopathy by studying 8 genealogically unrelated cases due to the same point mutation in TTID. Proximally, the vastii, biceps femoris and semimembranosus were involved with sparing of gracilis and sartorius. Distally, soleus, gastrocnemius, tibialis anterior, extensor hallicus and extensor digitorum were involved. This pattern contrasts with other distal myopathies and provides further support for the role of imaging in the clinical investigation of muscle disease.

Is the content of confabulation positive? An experimental study.

There has been little experimental work investigating the emotional content of confabulation, despite clinical descriptions of self-serving and affectively positive biases. False memories were elicited in 10 amnesic confabulating patients, 10 healthy controls and four amnesic control patients without confabulation. Memory protocols of the interviews with these groups were presented to naïve raters who were asked to rate the emotional valence of the listed confabulations. The false memories of the confabulating patients were found to distort previous experiences in ways significantly more pleasant and self-enhancing than those of controls. It was also found paradoxically that the more depressed the patients' mood the more positive the content of their confabulations. These findings suggest that the content of confabulation is mostly positive. The results have implications for the role of emotion and motivation in confabulation, as well as for the clinical management of confabulating patients.

Self-enhancing confabulation: revisiting the motivational hypothesis.

We report a patient who developed spontaneous confabulation following surgical clipping of an anterior communicating artery aneurysm. An autobiographical memory test was used to measure the emotional valence of the patient's self-representations in true and false memories. We found that his confabulations included significantly more positive self-representations than his true memories and that the overall valence of his confabulations was more positive than that of his true memories and than that of the memories of five healthy control participants of the same age and educational attainment. It is proposed that while cognitive dysfunction may explain how confabulations are formed, emotional factors may explain which specific confabulations are constructed.

Clinical features and natural history of neuroferritinopathy caused by the FTL1 460InsA mutation.

Neuroferritinopathy is a progressive potentially treatable adult-onset movement disorder caused by mutations in the ferritin light chain gene (FTL1). Features overlap with common extrapyramidal disorders: idiopathic torsion dystonia, idiopathic Parkinson's disease and Huntington's disease, but the phenotype and natural history have not been defined. We studied a genetically homogeneous group of 41 subjects with the 460InsA mutation in FTL1, documenting the presentation, clinical course, biochemistry and neuroimaging. The mean age of onset was 39.4 years (SD = 13.3, range 13-63), beginning with chorea in 50%, focal lower limb dystonia in 42.5% and parkinsonism in 7.5%. The majority reported a family history of a movement disorder often misdiagnosed as Huntington's disease. The disease progressed relentlessly, becoming generalized over a 5-10 year period, eventually leading to aphonia, dysphagia and severe motor disability with subcortical/frontal cognitive dysfunction as a late feature. A characteristic action-specific facial dystonia was common (65%), and in 63% there was asymmetry throughout the disease course. Serum ferritin levels were low in the majority of males and post-menopausal females, but within normal limits for pre-menopausal females. MR brain imaging was abnormal on all affected individuals and one presymptomatic carrier. In conclusion, isolated parkinsonism is unusual in neuroferritinopathy, and unlike Huntington's disease, cognitive changes are absent or subtle in the early stages. Depressed serum ferritin is common and provides a useful screening test in routine practice, and gradient echo brain MRI will identify all symptomatic cases.

Analysis of haemodynamic disturbance in the atherosclerotic carotid artery using computational fluid dynamics.

Computational fluid dynamics (CFD) provides a means for the quantitative analysis of haemodynamic disturbances in vivo, but most work has used phantoms or idealised geometry. Our purpose was to use CFD to analyse flow in carotid atherosclerosis using patient-specific geometry and flow data. Eight atherosclerotic carotid arteries and one healthy control artery were imaged with magnetic resonance angiography (MRA) and duplex ultrasound, and the data used to construct patient-specific computational models used for CFD and wall shear stress (WSS) analysis. There is a progressive change in three-dimensional (3-D) velocity profile and WSS profile with increasing severity of stenosis, characterised by increasing restriction of areas of low WSS, change in oscillation patterns, and progressive rise in WSS within stenoses and downstream jets. Areas of turbulent, retrograde flow and of low WSS are demonstrated in the lee of the stenoses. This study presents the largest CFD analysis of abnormal haemodynamics at the atheromatous carotid bifurcation using patient-specific data and provides the basis for further investigation of causal links between haemodynamic variables and atherogenesis and formation of unstable plaque. We propose that this provides a means for the prospective assessment of relative stroke risk in patients with carotid atherosclerosis.

Weights and measures: a new look at bisection behaviour in neglect.

Horizontal line bisection is a ubiquitous task in the investigation of visual neglect. Patients with left neglect typically make rightward errors that increase with line length and for lines at more leftward positions. For short lines, or for lines presented in right space, these errors may 'cross over' to become leftward. We have taken a new approach to these phenomena by employing a different set of dependent and independent variables for their description. Rather than recording bisection error, we record the lateral position of the response within the workspace. We have studied how this varies when the locations of the left and right endpoints are manipulated independently. Across 30 patients with left neglect, we have observed a characteristic asymmetry between the 'weightings' accorded to the two endpoints, such that responses are less affected by changes in the location of the left endpoint than by changes in the location of the right. We show that a simple endpoint weightings analysis accounts readily for the effects of line length and spatial position, including cross-over effects, and leads to an index of neglect that is more sensitive than the standard measure. We argue that this novel approach is more parsimonious than the standard model and yields fresh insights into the nature of neglect impairment.

Imaging of metastatic orbital leiomyosarcoma.

A 74-year-old man with a previous history of lower leg soft tissues leiomyosarcoma and multiple metastasis presented with a progressive painless proptosis of the left eye. Orbital ultrasound, CT, and MRI revealed a large mass in the left medial orbit. The mass was surgically removed and pathologic examination confirmed the diagnosis of a metastatic orbital leiomyosarcoma. The imaging characteristics of this rare tumor are comprehensively detailed, using complementary ultrasound, CT, and MRI, the combination of which allowed planning of total excision of the lesion.

Subclinical semitendinosus and obturator externus involvement defines an autosomal dominant myopathy with early respiratory failure.

We recently described a dominant limb myopathy characterised by early respiratory failure whilst affected individuals were still ambulant (autosomal dominant myopathy with early respiratory failure). Early diagnosis and exclusion of this disorder is difficult because of the insidious onset in late adult life and the highly selective muscle involvement, both clinically and pathologically. We performed muscle magnetic resonance imaging on seven cases of autosomal dominant myopathy with early respiratory failure (age range 37-66 years, 4 male) and show selective early involvement of semitendinosus and obturator externus on magnetic resonance imaging that cannot be detected clinically, with different rates of progression in closely related muscles. These findings are specific to autosomal dominant myopathy with early respiratory failure and enable early non-invasive diagnosis for individuals at risk.

Muscle MRI findings in patients with limb girdle muscular dystrophy with calpain 3 deficiency (LGMD2A) and early contractures.

Limb girdle muscular dystrophy 2A is a common variant secondary to mutations in the calpain 3 gene. A proportion of patients has early and severe contractures, which can cause diagnostic difficulties with other conditions. We report clinical and muscle magnetic resonance imaging findings in seven limb girdle muscular dystrophy 2A patients (four sporadic and three familial) who had prominent and early contractures. All patients showed a striking involvement of the posterior thigh muscles. The involvement of the other thigh muscles was variable and was related to clinical severity. Young patients with minimal functional motor impairment showed a predominant involvement of the adductors and semimembranosus muscles while patients with restricted ambulation had a more diffuse involvement of the posterolateral muscles of the thigh and of the vastus intermedius with relative sparing of the vastus lateralis, sartorius and gracilis. At calf level all patients showed involvement of the soleus muscle and of the medial head of the gastrocnemius with relative sparing of the lateral head. MRI findings were correlated to those found in two patients with the phenotype of limb girdle muscular dystrophy 2A without early contractures and the pattern observed was quite similar. However, the pattern observed in limb girdle muscular dystrophy 2A is different from that reported in other muscle diseases such as Emery-Dreifuss muscular dystrophy and Bethlem myopathy which have a significant clinical overlap with limb girdle muscular dystrophy 2A once early contractures are present. Our results suggest that muscle MRI may help in recognising patients with limb girdle muscular dystrophy 2A even when the clinical presentation overlaps with other conditions, and may therefore, be used as an additional investigation to target the appropriate biochemical and genetic tests.