Trainee radiologist reports as a source of confirmation bias in radiology.

AIM: To assess and quantify the relationship between trainee reporting and radiology errors. MATERIALS AND METHODS: A retrospective analysis of the 100 most recent cases reviewed by a discrepancy forum in a tertiary neuroradiology service was performed. Data on the time of the scan and the presence of a trainee report were collected, with comparison being made between the cohort of erroneous reports and the overall service. RESULTS: Although out-of-hours imaging only constituted 18% of the overall service, 36% of erroneous reports originated from scans performed out-of-hours. Eighteen percent of scans were first reported by a trainee and then checked by a consultant, with the remaining 82% being solely reported by the consultant. Despite this, 52% of errors were from consultant-checked trainee reports. CONCLUSION: Although out-of-hours imaging has long been associated with error, this study identifies consultant checking of trainee reports as another error-associated reporting context. This is likely to relate to confirmation bias, in which the pre-existing trainee report may result in inattentional blindness on the part of the checking consultant. Awareness of this phenomenon is important for the reduction of error in this specific and widely underestimated reporting context.

The disengage deficit in hemispatial neglect is restricted to between-object shifts and is abolished by prism adaptation.

We sought to determine the effects of prism adaptation on peripherally cued visual attention shifting in patients with spatial neglect, using a task devised by Egly et al. (J Exp Psychol Gen 123:161-177, 1994) based on the classic Posner paradigm. This task allowed a comparison of "within-object" versus "between-object" attention shifts. A display was presented containing two parallel outline rectangles, and subjects were asked to make rapid responses to a target, which would appear at one end of one of the rectangles. The target location was pre-cued with 75% validity: on invalid trials attention was directed either to the other end of the same rectangle, or to the other rectangle. Healthy subjects and right-hemisphere patients without neglect showed a left-right symmetrical pattern, with a larger validity effect when required to shift attention between rectangles, thus indicating a greater difficulty of attention-shifting between than within the respective shapes. The neglect patients showed the typical leftward "disengage deficit" previously observed in neglect, but only for attention shifts between objects, indicating that the effect is object-based rather than purely spatial. A comparison of vertical and horizontal shift costs showed that this attention-shifting deficit for left-hemifield target stimuli was directional rather than hemifield-based: it was absent for vertical shifts of attention within the left hemifield. Finally, we found that prism adaptation abolished the disengage deficit. We found no effects of prism adaptation in the control subjects. We argue that prism adaptation has a powerful effect on one of the fundamental manifestations of the neglect syndrome.

THE MAYAK WORKER DOSIMETRY SYTEM (MWDS-2013): DETERMINATION OF THE INDIVIDUAL SCENARIO OF INHALED PLUTONIUM INTAKE IN THE MAYAK WORKERS.

In order to estimate doses of workers exposed to plutonium, it is necessary to make assumptions about both the route and the time course of intake. The objective of this study was to determine a time course for the inhalation rate for plutonium (intake regime) useful for biokinetic modeling. Records from workplace air sampling, personnel biophysical examinations and autopsy data from former Mayak Production Association (MPA) workers were used. Plutonium accumulation strongly correlated with the volumetric activity of plutonium in workplace air. Using data from activity in air at MPA workplaces over time, a three-step function of intake was adopted. The adequacy of this three-step function was tested by comparing predicted doses using more complicated intake regimes. Uncertainties on the three-step function were also characterized based on air sampling data. The three-step function was assumed to be common to all workers, but an individual intake regime for each worker was calculated by convoluting it with the worker's actual employment history.

Proton magnetic resonance spectroscopy in frontotemporal dementia.

This study of frontotemporal dementia (FTD) was carried out to determine whether MR spectroscopy can provide an in vivo marker for the neuronal loss and gliosis that occur in this condition. We compared spectra in frontal and temporal regions known to be affected early in the course of the disease with spectra in the parietal lobe that is spared until late stages of FTD. We were interested in the relative concentrations of two compounds, NAA (a marker of neuronal integrity) and mI (a marker of gliosis), expressed as ratios to creatine (a relatively stable brain constituent). MR spectroscopy was performed on the temporal, parietal, and anterior cingulate cortices of five patients with the established semantic dementia form of FTD, two patients with the frontal form of FTD and 13 age matched controls. Structural MRI and neuropsychometry were also performed. Patients with FTD had reduced NAA/Cr in frontal and temporal, but not parietal lobes. The two patients with the frontal form of FTD had increased mI/Cr in their cingulate cortices. These data show for the first time that MR spectroscopy can reveal regionally selective abnormalities in patients with FTD. This opens up the possibility of using MR spectroscopy as a clinical tool to identify earlier presentations of the condition.

Reversible cytotoxic cerebral edema in cerebral fat embolism.

We present a case of cerebral fat embolism (CFE) that demonstrated evidence of diffuse white matter cytotoxic edema on diffusion-weighted magnetic resonance imaging, in addition to punctate hyperintensities on T2-weighted and diffusion-weighted imaging. The case suggests that CFE represents a combination of occlusive arteriolar disease and secondary neurotoxicity.

Comparison of image quality, diagnostic confidence and interobserver variability in contrast enhanced MR angiography and 2D time of flight angiography in evaluation of carotid stenosis.

The aim of this study was to compare image quality, level of diagnostic confidence and interobserver agreement in assessment of carotid stenosis with contrast enhanced MR angiography (CE MRA) in comparison with 2D time of flight MR angiography (2D TOF MRA). 60 carotid arteries in 30 patients were examined by three observers. Image quality and diagnostic confidence were assessed on the basis of a visual analogue scale. Interobserver variability was assessed with the help of intraclass correlation coefficient. Median values on the visual analogue scale for image quality and diagnostic confidence were higher for CE MRA compared with 2D TOF MRA for all three observers. Higher intraclass correlation values were recorded for interobserver variability for CE MRA compared with 2D TOF MRA both for visual estimation of carotid stenosis as well as for measurement of carotid stenosis on the basis of North American Symptomatic Carotid Endarterectomy Trial (NASCET) and European Carotid Surgery Trial (ECST) criteria. CE MRA provides better image quality, higher level of diagnostic confidence and more interobserver agreement compared with 2D TOF MRA.

Novel HSPB1 mutation causes both motor neuronopathy and distal myopathy.

OBJECTIVE: To identify the cause of isolated distal weakness in a family with both neuropathic and myopathic features on EMG and muscle histology. METHODS: Case study with exome sequencing in 2 affected individuals, bioinformatic prioritization of genetic variants, and segregation analysis of the likely causal mutation. Functional studies included Western blot analysis of the candidate protein before and after heat shock treatment of primary skin fibroblasts. RESULTS: A novel HSPB1 variant (c.387C>G, p.Asp129Glu) segregated with the phenotype and was predicted to alter the conserved α-crystallin domain common to small heat shock proteins. At baseline, there was no difference in HSPB1 protein levels nor its binding partner αB-crystallin. Heat shock treatment increased HSPB1 protein levels in both patient-derived and control fibroblasts, but the associated increase in αB-crystallin expression was greater in patient-derived than control fibroblasts. CONCLUSIONS: The HSPB1 variant (c.387C>G, p.Asp129Glu) is the likely cause of distal neuromyopathy in this pedigree with pathogenic effects mediated through binding to its partner heat shock protein αB-crystallin. Mutations in HSBP1 classically cause a motor axonopathy, but this family shows that the distal weakness can be both myopathic and neuropathic. The traditional clinical classification of distal weakness into "myopathic" or "neuropathic" forms may be misleading in some instances, and future treatments need to address the pathology in both tissues.

Radiological characterization of spinocerebellar ataxia type 6.

Spinocerebellar ataxia type 6 (SCA-6) is a rare, autosomal dominant neurodegenerative condition characterized by adult onset cerebellar ataxia and ocular movement disorders. The presentation is non-specific, and radiological characterization would be of diagnostic benefit. There is little published on the radiological appearances of SCA-6, and there are conflicting reports in the literature. We report the radiological findings in a group of 10 patients with SCA-6.

Spatial ability in radiologists: a necessary prerequisite?

Visuospatial ability is fundamental to the cognitive understanding of the three-dimensional environment and is widely recognized as an important skill in the performance of challenging visuospatial tasks. Its contribution to attainment and performance in a variety of professional disciplines is recognized, but there is relatively little known in relation to its relevance in radiological practice. On the basis of a review of the existing cognitive psychological literature and on the basis of the author's own observations, and on the assumption that spatial ability is of increasing and fundamental importance to high-level performance as a radiologist, it is proposed that consideration should be given to the testing of visuospatial ability as part of the selection process for prospective applicants to radiology training programmes.

Radiological appearances in olfactory dysfunction: pictorial review.

BACKGROUND: Olfactory dysfunction is a common condition that may in some cases require imaging to investigate a potential underlying cause. OBJECTIVES: This review describes the anatomy of normal olfaction and illustrates the pathological substrates of olfactory dysfunction amenable to imaging.

Evaluation of cross-sectional luminal morphology in carotid atherosclerotic disease by use of spiral CT angiography.

BACKGROUND AND PURPOSE: This study sought to determine the frequency of noncircular lumens in patients with significant carotid atherosclerotic disease and to evaluate the effect of noncircular lumens on stenosis measurement derived from angiographic projections. METHODS: One hundred consecutive patients presenting with an internal carotid artery stenosis of at least 50% were imaged with spiral CT angiography. The transverse morphology of the diseased lumen was assessed on axial images, and the frequency of noncircular lumens was determined. In these cases, maximum intensity projection angiograms were reconstructed in standardized angiographic planes and in a plane selected according to the luminal obliquity, which was chosen to optimize the angiographic representation of the maximal stenosis. North American Symptomatic Carotid Endarterectomy Trial (NASCET) measurements were calculated from the maximum intensity projection images, and differences between values obtained from standard and optimized projections were recorded. RESULTS: Noncircular lumens were observed in 18 of 100 patients and consisted of elliptical and linear transverse profiles. The transverse orientation of the lumen in these cases ranged from +90 degrees to -87 degrees relative to the anteroposterior plane. An increase in the calculated NASCET stenosis was demonstrated when measurements were obtained from angiographic reconstructions obtained in the exact plane of the luminal obliquity compared with standard angiographic projections. As a result, the stenosis severity was upgraded from moderate to severe in 2 patients. CONCLUSIONS: Noncircular transverse luminal profiles are not uncommon and may introduce error into NASCET calculations obtained from standard angiographic projections.

Intracellular aluminium inhibits acetylcholine- and caffeine-evoked Ca2+ mobilization.

The effect of intracellular aluminium on Ca2+ signalling in single internally perfused mouse pancreatic acinar cells was investigated by measurement of the Ca2(+)-dependent Cl- current using the patch-clamp whole-cell recording configuration. Acetylcholine (ACh) normally evoked a pulsatile Ca2(+)-dependent Cl- current, but when AlCl3 (1 mM) was present in the internal perfusion solution the ACh responses were virtually absent. When aluminium was acutely infused into the internal perfusion solution, the ACh-evoked Ca2+ signals and also the caffeine-evoked responses quickly disappeared, but the Ca2+ ionophore, ionomycin (100 nM), could still induce a large increase in the Cl- current. It is concluded that intracellular aluminium can abolish receptor-activated intracellular Ca2+ release probably by inhibition of Ca2(+)-induced Ca2+ release.

Preserved obstacle avoidance during reaching in patients with left visual neglect.

We asked 12 patients with left visual neglect to bisect the gap between two cylinders or to reach rapidly between them to a more distal target zone. Both tasks demanded a motor response but these responses were quite different in nature. The bisection response was a communicative act whereby the patient indicated the perceived midpoint. The reaching task carried no imperative to bisect the gap, only to maintain a safe distance from either cylinder while steering to the target zone. Optimal performance on either task could only be achieved by reference to the location of both cylinders. Our analysis focused upon the relative influence of the left and right cylinders on the lateral location of the response. In the bisection task, all neglect patients showed qualitatively the same asymmetry, with the left cylinder exerting less influence than the right. In the reaching task, the neglect group behaved like normal subjects, being influenced approximately equally by the two cylinders. This was true for all bar two of the patients, who showed clear neglect in both tasks. We conclude that the visuomotor processing underlying obstacle avoidance during reaching is preserved in most patients with left visual neglect.

Avoidance of obstacles in the absence of visual awareness.

The spatial character of our reaching movements is extremely sensitive to potential obstacles in the workspace. We recently found that this sensitivity was retained by most patients with left visual neglect when reaching between two objects, despite the fact that they tended to ignore the leftward object when asked to bisect the space between them. This raises the possibility that obstacle avoidance does not require a conscious awareness of the obstacle avoided. We have now tested this hypothesis in a patient with visual extinction following right temporoparietal damage. Extinction is an attentional disorder in which patients fail to report stimuli on the side of space opposite a brain lesion under conditions of bilateral stimulation. Our patient avoided obstacles during reaching, to exactly the same degree, regardless of whether he was able to report their presence. This implicit processing of object location, which may depend on spared superior parietal-lobe pathways, demonstrates that conscious awareness is not necessary for normal obstacle avoidance.

Arsenic and Ayurveda.

Manufacture of an Ayurvedic arsenic-containing compound is described, which is currently in use in India to control blood counts of patients with haematological malignancies. The efficacy and side effects of this compound are evaluated in the light of the fact that arsenic was recognised to be of use in the control of blood counts from patients with chronic myeloid leukaemia as long as 100 years ago, in the West.

Resolution of third nerve paresis after endovascular management of aneurysms of the posterior communicating artery.

The effect of endovascular treatment on the recovery of neural function in patients with third nerve palsy caused by an aneurysm of the posterior communicating artery is poorly documented. We report three cases in which third nerve paresis resolved completely within 2 to 3 weeks of endovascular occlusion of a posterior communicating artery aneurysm.

Evaluation of magnetic resonance myelography in the investigation of cervical spondylotic radiculopathy.

The objective of this study was to prospectively evaluate the accuracy of MR myelography for the demonstration of foraminal nerve root impingement in cervical spondylotic radiculopathy. 40 patients with cervical spondylotic radiculopathy were imaged with conventional MRI and with MR myelography. The diagnostic accuracy of these imaging strategies for the demonstration of exit foraminal stenosis was calculated relative to a gold standard of the combination of conventional MRI and MR myelography. Conventional MRI had a sensitivity of 88.9%, specificity of 99.1%, and diagnostic accuracy of 94.5% for the demonstration of exit foraminal disease (p<0.001). MR myelography alone had a sensitivity of 84.4%, a specificity of 90.1%, and diagnostic accuracy of 88% (p<0.001). However, the addition of MR myelography increased the diagnostic yield of the MR examination for the detection of foraminal stenotic disease. MR myelography is a useful adjunct to conventional MRI in the investigation of cervical spondylotic radiculopathy.

Use of serial proton magnetic resonance spectroscopy to differentiate low grade glioma from tumefactive plaque in a patient with multiple sclerosis.

We report on the use of serial proton MR spectroscopy ((1)H MRS) to differentiate between glioma and tumefactive plaque in a known multiple sclerosis (MS) patient who developed a symptomatic cerebral space occupying lesion. Gliomas and acute MS plaques may have indistinguishable chemical resonance spectra, whereas that of chronic plaque is distinct. In our case (1)H MRS demonstrated elevated concentrations of choline, lactate and lipid, with reduced N-acetyl aspartate, a pattern consistent with either low grade glioma or acute demyelinating plaque. A repeat study 4 months later showed no change, this was felt to be incompatible with the natural history of an acute plaque and low grade glioma was diagnosed. Surgical removal of the lesion revealed an oligodendroglioma, confirming the imaging findings.

Use of colour duplex ultrasound to diagnose giant cell arteritis in a case of visual loss of uncertain aetiology.

Giant cell arteritis is a common condition that can result in permanent visual loss. It has traditionally been diagnosed by invasive temporal artery biopsy in cases of clinical suspicion. The findings of colour duplex ultrasound have recently been described. We report the use of duplex ultrasound to diagnose temporal arteritis, with clinicopathological correlation, and discuss the possible application of this non-invasive technique to the management of giant cell arteritis.

Vertebral synovial osteochondromatosis with compressive myelopathy.

STUDY DESIGN: A case report of vertebral synovial osteochondromatosis with compressive myelopathy. OBJECTIVES: To describe the clinical, radiologic, and histopathologic features of vertebral facet synovial osteochondromatosis with compressive myelopathy. SUMMARY OF BACKGROUND DATA: There has been only one previously reported case of synovial osteochondromatosis affecting the vertebral facet joint and no previous report of associated compressive myelopathy. METHODS: The case history, radiology, surgical findings, and histopathology are reviewed. RESULTS: Vertebral facet synovial osteochondromatosis is a potential and readily manageable cause of spinal cord compression. CONCLUSIONS: Synovial osteochondromatosis of the vertebral facet joint should be considered as a cause of compressive myelopathy.