Daniel Warren

Imaging assessment of traumatic brain injury

Traumatic brain injury (TBI) constitutes injury that occurs to the brain as a result of trauma. It should be appreciated as a heterogeneous, dynamic pathophysiological process that starts from the moment of impact and continues over time with sequelae potentially seen many years after the initial event. Primary traumatic brain lesions that may occur at the moment of impact include contusions, haematomas, parenchymal fractures and diffuse axonal injury. The presence of extra-axial intracranial lesions such as epidural and subdural haematomas and subarachnoid haemorrhage must be anticipated as they may contribute greatly to secondary brain insult by provoking brain herniation syndromes, cranial nerve deficits, oedema and ischaemia and infarction. Imaging is fundamental to the management of patients with TBI. CT remains the imaging modality of choice for initial assessment due to its ease of access, rapid acquisition and for its sensitivity for detection of acute haemorrhagic lesions for surgical intervention. MRI is typically reserved for the detection of lesions that may explain clinical symptoms that remain unresolved despite initial CT. This is especially apparent in the setting of diffuse axonal injury, which is poorly discerned on CT. Use of particular MRI sequences may increase the sensitivity of detecting such lesions: diffusion-weighted imaging defining acute infarction, susceptibility-weighted imaging affording exquisite data on microhaemorrhage. Additional advanced MRI techniques such as diffusion tensor imaging and functional MRI may provide important information regarding coexistent structural and functional brain damage. Gaining robust prognostic information for patients following TBI remains a challenge. Advanced MRI sequences are showing potential for biomarkers of disease, but this largely remains at the research level. Various global collaborative research groups have been established in an effort to combine imaging data with clinical and epidemiological information to provide much needed evidence for improvement in the characterisation and classification of TBI and in the identity of the most effective clinical care for this patient cohort. However, analysis of collaborative imaging data is challenging: the diverse spectrum of image acquisition and postprocessing limits reproducibility, and there is a requirement for a robust quality assurance initiative. Future clinical use of advanced neuroimaging should ensure standardised approaches to image acquisition and analysis, which can be used at the individual level, with the expectation that future neuroimaging advances, personalised to the patient, may improve prognostic accuracy and facilitate the development of new therapies.

Cause and outcome of cerebellar mutism: evidence from a systematic review

PurposeCerebellar mutism is a serious neurosurgical complication after posterior fossa surgery, but the cause, incidence and outcome remain incompletely defined. The aim of this paper was to identify and review all reports of this phenomenon to better delineate and improve the evidence base.MethodsA systematic search and retrieval of databases was conducted using advanced search techniques. Review/outcomes criteria were developed, and study quality was determined.ResultsThe retrieval identified 2,281 papers of which 96 were relevant, identifying 650 children with cerebellar mutism. Causative factors, clinical features and outcomes were reported variably; papers focussed on multiple areas, the majority reporting incidence in single or series of case studies with little or no analysis further than description.ConclusionsThe complexity and variability of data reporting, likely contributing factors and outcomes make cerebellar mutism difficult to predict in incidence and the degree of impact that may ensue. A clear and accepted universal definition would help improve reporting, as would the application of agreed outcome measures. Clear and consistent reporting of surgical technique remains absent. Recommendations for practice are provided.

Basal Ganglia Calcification in a Patient With Beta-Propeller Protein-Associated Neurodegeneration

BACKGROUND Beta-propeller protein-associated neurodegeneration is a newly described X-linked dominant condition due to heterozygous mutations in WDR45. The condition is associated with characteristic changes on brain magnetic resonance imaging. Previous literature relating to this disorder has not specifically referred to intracranial calcification. METHODS A female patient presented with significant developmental delay in early childhood and subsequently demonstrated neurodegeneration with progressive dystonia and dementia in her third decade. Brain magnetic resonance imaging revealed low signal in the substantia nigra and both globus pallidi on T2-weighted imaging, with no eye-of-the-tiger sign. Computed tomography revealed bilateral dense calcification of the globus pallidus. We performed Sanger sequencing of the WDR45 gene in the patient and her parents. RESULTS We identified a heterozygous c.488del C p.Pro163Argfs*34 variant in exon 8 of WDR45. Neither parent carried the same mutation, indicating that the molecular change had occurred de novo. CONCLUSIONS Although the characteristic features of beta-propeller protein-associated neurodegeneration were present in our patient, the observation of basal ganglia calcification was considered atypical. Previous descriptions of basal ganglia calcification in individuals with neuronal brain iron accumulation led us to review the frequency of calcification in these disorders.

Migration of intraocular silicone oil into the brain

A 74-year-old woman gave a 6-month history of predominately right-sided parietal headaches, often worse on waking. Her history included left phthisis bulbi (atrophy and calcification of the eye), resulting from multiple attempted surgical repairs for retinal detachment 20 years previously. She wore a coloured contact lens over her left eye for cosmetic purposes. Neurological examination was normal. An unenhanced CT brain scan of her head demonstrated a high-attenuation abnormality in the left vitreous cavity with posterior extension along the optic nerve. There were further foci of high attenuation in the suprasellar region and in the frontal horn of the right lateral ventricle (figures 1 …

Pre-surgical mapping of eloquent cortex for paediatric epilepsy surgery candidates: Evidence from a review of advanced functional neuroimaging

PURPOSE A review of all published evidence for mapping eloquent (motor, language and memory) cortex using advanced functional neuroimaging (functional magnetic resonance imaging [fMRI] and magnetoencephalography [MEG]) for paediatric epilepsy surgery candidates has not been conducted previously. Research in this area has predominantly been in adult populations and applicability of these techniques to paediatric populations is less established. METHODS A review was performed using an advanced systematic search and retrieval of all published papers examining the use of functional neuroimaging for paediatric epilepsy surgery candidates. RESULTS Of the 2724 papers retrieved, 34 met the inclusion criteria. Total paediatric participants identified were 353 with an age range of 5 months-19 years. Sample sizes and comparisons with alternative investigations to validate techniques are small and variable paradigms are used. Sensitivity 0.72 (95% CI 0.52-0.86) and specificity 0.60 (95% CI 0.35-0.92) values with a Positive Predictive Value of 74% (95% CI 61-87) and a Negative Predictive Value of 65% (95% CI 52-78) for fMRI language lateralisation with validation, were obtained. Retrieved studies indicate evidence that both fMRI and MEG are able to provide information lateralising and localising motor and language functions. CONCLUSIONS A striking finding of the review is the paucity of studies (n=34) focusing on the paediatric epilepsy surgery population. For children, it remains unclear which language and memory paradigms produce optimal activation and how these should be quantified in a statistically robust manner. Consensus needs to be achieved for statistical analyses and the uniformity and yield of language, motor and memory paradigms. Larger scale studies are required to produce patient series data which clinicians may refer to interpret results objectively. If functional imaging techniques are to be the viable alternative for pre-surgical mapping of eloquent cortex for children, paradigms and analyses demonstrating concordance with independent measures must be developed.

Holocord syrinx associated with haemangioblastoma

A 50-year-old man gave a 6-year history of muscle wasting and weakness of both legs. He had noticed marked muscle loss across his chest and back and ‘spasms’ of his legs at night, often induced by coughing or sneezing. There were no sensory symptoms or problems with sphincters, speech or swallowing. On examination, there was muscle wasting in both legs and in the pectoral muscles, but no fasciculations. There was increased tone in all four limbs, with several beats of clonus in the legs. His strength was normal when examined on the couch, although he was adamant that he was not as strong as he used to be. Reflexes were brisk bilaterally in all four limbs and both plantars were upgoing. Sensations to fine touch and to joint-position sense were normal; vibration sense …

New General Medical Council language checks to be introduced in the summer. How will radiology reports fare

Sir d It was of interest to read that, “on April 23rd the GMC will update the guidance Good Medical Practice to include an explicit duty about doctors’ knowledge of English. From this date, an insufficient knowledge of English will also become a distinct ground of impaired fitness to practice. New language checks will be introduced in the summer.”1 As radiologists we are well reminded of our responsibility for language proficiency and of the necessity for comprehensive and interpretable reports. The radiology report acts as the primary method of communication between radiologist and referrer, and any errors in the language used may have significant adverse clinical consequences.2,3 The Royal College of Radiologists states in Standards for the Reporting and Interpretation of Imaging Investigations that, “the wording of the report should be clear.”4 Accuracy has been cited as the single most important characteristic that physicians wish of a radiology report, with clarity, completeness, and timeliness also highly sought after.5 The introduction of voice recognition (VR) has undoubtedly improved timeliness, but it has not necessarily enhanced accuracy. It is known that one of the major disadvantages of VR is transcription errors fromword deletion and wrong word substitution to reports containing confusing and inaccurate sentences.6 Pezzullo et al.7 reported that 35% of verified VR reports contained errors. Quint and colleagues8 found error rates of 22% with most radiologists believing that their report error rates were much lower than they actually were. Clinical audit provides a valuable forum for interrogation of clinical practice against a reference standard. It is conceivable with proofreading that the reference standard grammatical error-rate for a radiology report should be zero. Recently, 50 consecutive verified reports from six consultant neuroradiologists in our department were interrogated for grammatical errors in six categories, reflecting previously published methodology.6 The categories comprised (a) wrongword substitution, (b) nonsense phrases, (c) deletion, (d) insertion, (e) punctuation, and (f) other (e.g., spelling). A nonsense phrase was defined as a sentence that was meaningless or one that contained words completely irrelevant to the report. Two independent