Consistency of Radiological Grading of Cervical Foraminal Stenosis.

BACKGROUND: The degree of cervical foraminal stenosis on MRI scans may be measured and categorised using the Kim or modified Kim methods. These grading scales have not previously been validated in a cohort of patients awaiting surgery. OBJECTIVES: To establish the normal foraminal and root diameters as well as the consistency of inter and intra-rater grading using the Kim and modified Kim grading systems in pre-operative surgical patients. METHODS: Asymptomatic cervical nerve roots and foramina demonstrated on the pre-operative MRI scans of adult surgical patients with cervical radiculopathy were measured and categorised by six raters using the Kim and modified Kim grading methods. Repeat "second pass" measurements were made by the same assessors on the same images a minimum of one month later. RESULTS: Foraminal diameters (mm) in asymptomatic foramina were C2/C3 (mean±SD): 4.18±1.44, C3/C4 2.96±1.23, C4/C5 3.02±1.19, C5/C6 3.15±1.33, C6/C7 3.53±1.36, C7/T1 3.93±1.34. Nerve root diameters were C3 3.11±0.87, C4 2.95±0.77, C5 2.56±0.73, C6 2.26±0.76, C7 2.56±0.82, C8 3.83±0.86. Inter-rater consistency was kappa [95% CI]: Kim 0.01 [0.00, 0.03], modified Kim 0.08 [0.05, 0.10]. Intra-rater consistency was kappa [95% CI]: Kim 0.81 [0.77, 0.86], modified Kim 0.69 [0.62, 0.76]. CONCLUSION: There was poor inter-rater consistency but good intra-rater consistency when assessing the severity of foraminal stenosis on axial T2 MRI scans. Foraminal diameter was narrowest at C3/C4 and C4/C5, whereas the smallest root diameter was C5/C6. Volumetric or oblique MR may improve consistency.

Should we be moving to a national standardized non-gadolinium MR imaging protocol for the surveillance of vestibular schwannomas?

OBJECTIVES:: To examine whether the model of Getting It Right First Time (GIRFT) could be relevant to the surveillance of non-operated vestibular schwannomas (vs) by testing the following hypotheses: (1) in the UK there is a great variation in the imaging protocol for the follow-up of vs; (2) high-resolution, T 2 weighted MRI (HRT 2W-MRI) has an equivalent accuracy to gadolinium-enhanced T 1 weighted MRI (Gd-MRI) in the assessment of vs size and; (3) imaging with HRT 2W-MRI rather than Gd-MRI could offer financial savings. METHODS:: Two neuroradiologists independently performed measurements of 50 vs imaged with HRT 2W-MRI and Gd-MRI. Differences in mean tumour measurements between HRT 2W-MRI and Gd-MRI were determined, as were intra- and interobserver concordance. Level of agreement was measured using Bland-Altman plots. Consultant neuroradiologists within 30 adult neurosurgical units in the UK were contacted via email and asked to provide the MRI protocol used for the surveillance of non-operated vs in their institution. The financial difference between scanning with HRT 2W-MRI and Gd-MRI was determined within Leeds Teaching Hospitals NHS Trust. RESULTS:: There was no statistically significant difference in the mean diameter of vs size, measured on HRT 2W-MRI and Gd-MRI (p = 0.28 & p = 0.74 for observers 1 and 2 respectively). Inter- and intraobserver concordance were excellent (Interclass correlation coefficient = 0.99, Interclass correlation coefficient ≥ 0.98 respectively). Differences between the two sequences were within limits of agreement. 26 of 30 UK neuroscience centres (87 % response rate) provided imaging protocols. 16 of the 26 (62%) centres use Gd-MRI for the surveillance of vs. HRT 2-MRI is £36.91 cheaper per patient than Gd-MRI. CONCLUSION:: Variation exits across UK centres in the imaging surveillance of non-operated vs. HRT 2W-MRI and Gd-MRI have equivalent accuracy when measuring vs. Imaging with HRT 2W-MRI rather than Gd-MRI offers potential financial savings. ADVANCES IN KNOWLEDGE:: This study highlights the potential health and economic benefits of a national standardized imaging protocol for the surveillance of non-operated vs.

Low-Grade Glioma with Foci of Early Transformation Does Not Necessarily Require Adjuvant Therapy After Radical Surgical Resection.

BACKGROUND: Low-grade glioma (LGG) is a slow-growing tumor often found in young adults with minimal or no symptoms. As opposed to true low-grade lesions such as dysembryoplastic neuroepithelial tumors, they are associated with continuous growth and inevitable malignant transformation. METHODS: Case series of patients who have had en bloc resection of LGG with foci of anaplasia found embedded within the tumor specimen and not at margins. Patients were offered and agreed to a conservative approach avoiding adjuvant therapy. RESULTS: In the current case series, we describe a small subset of LGG that have shown foci of high-grade glioma but have shown behavior and growth tendencies similar to LGG after radical surgical resection. No patient to date has shown recurrent disease requiring adjuvant therapy. CONCLUSIONS: This case series supports the use of early aggressive surgical treatment of grade II gliomas that are premalignant. It acts as proof of concept that after radical resection, the presence of small foci of transformation embedded within grade II tumor may be treated with close radiologic surveillance rather than immediate adjuvant therapy.

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.

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.

Monitoring the changing pattern of delivery of paediatric epilepsy surgery in England--an audit of a regional service and examination of national trends.

PURPOSE: The demand for paediatric epilepsy surgery in the UK greatly exceeds the number of operations performed. Hence, Children's Epilepsy Surgery Service (CESS) was commenced in 2012. This study is aimed to characterise the changes in service delivery in the North East of England Paediatric Neuroscience Network and nationally. METHODS: A retrospective cohort study of paediatric epilepsy surgery in Leeds between 2005 and 2012 is presented followed by analysis of British Paediatric Neurosurgical Group (BPNG) data before and after CESS commissioning. RESULTS: During the study period, 42 children underwent epilepsy surgery in Leeds. The commonest aetiologies were neoplasm (33%), focal cortical dysplasia (19%) and mesial temporal sclerosis (19%). Seizure outcome was 71 % EngelI and 83% EngelI+II. Complications included one infection (2%), two temporary (5%) and one permanent (2%) motor deficits, three new/worsened visual field deficits (7%). There were six re-craniotomies (14%). The BPNG data show a 48% increase in paediatric epilepsy surgery in England between 2009 (90 cases) and 2012 (133 cases), and a 20% fall in 2013 (106 cases)--the first calendar year for CESS. On average, 64% of all operations were performed in London. CONCLUSIONS: The number of children receiving surgery for epilepsy in England had increased annually up to, and declined after, the establishment of CESS centres. The yearly caseload in neurosurgical units outside of London is small. The outcomes from Leeds are comparable to those published elsewhere. Other UK units are encouraged to publish outcomes to facilitate patient, commissioner and provider decision making.

Serial MRI to determine the effect of dexamethasone on the cerebral pathology of tuberculous meningitis: an observational study.

BACKGROUND: Adjunctive dexamethasone increases survival from tuberculous meningitis, but the underlying mechanism is unclear. We aimed to determine the effect of dexamethasone on cerebral MRI changes and their association with intracerebral inflammatory responses and clinical outcome in adults treated for tuberculous meningitis. METHODS: Cerebral MRI was undertaken, when possible, at diagnosis and after 60 days and 270 days of treatment in adults with tuberculous meningitis admitted to two hospitals in Vietnam. Patients were randomly assigned either dexamethasone (n=24) or placebo (n=19) and received 9 months of treatment with standard first-line antituberculosis drugs. We assessed associations between MRI findings, treatment allocation, and resolution of fever, coma, cerebrospinal fluid inflammation, and neurological outcome. FINDINGS: 83 scans were done for 43 patients: 19 given placebo, 24 given dexamethasone. Basal meningeal enhancement (82%) and hydrocephalus (77%) were the most common presenting findings. Fewer patients had hydrocephalus after 60 days of treatment with dexamethasone than after placebo treatment (p=0.217). Tuberculomas developed in 74% of patients during treatment and in equal proportions in the treatment groups; they were associated with long-term fever, but not relapse or poor clinical outcome. The basal ganglia were the most common site of infarction; the proportion with infarction after 60 days was halved in the dexamethasone group (27%vs 58%, p=0.130). INTERPRETATION: Dexamethasone may affect outcome from tuberculous meningitis by reducing hydrocephalus and preventing infarction. The effect may have been under-estimated because the most severe patients could not be scanned.