Jeremy Macmullen-Price

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.

Susac's syndrome

A 34-year-old right-handed woman, with frequent episodic headaches, typical of migraine with visual aura, presented in December 2010. Two months later, she reported episodes of transient numbness over the left side of her face, arm and leg. There were several brief episodes of diplopia and the sudden onset of painless persistent scotoma in the lower visual field. She attended the ophthalmology clinic and was diagnosed with a left superior temporal branch retinal artery occlusion (figure 1). There was no relevant past or family history and no alcohol or recreational drug history. She had no vascular risk factors. Figure 1 Retinal photographs (A) and fluorescein angiography of the left eye (B) showing occlusion of left superior temporal branch of retinal artery (arrow). One month later, she developed increasing migraine with visual aura and hemisensory disturbances. Cardiac and neurological examinations were normal. She was started on aspirin. Initial MR brain imaging and MR angiography of the intracranial and extracranial arteries were normal. In May 2011, she started getting more migrainous headaches associated with vomiting, non-positional prolonged isolated vertigo and an episode of word-finding difficulty. A …

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.

CEREBRAL FAT EMBOLISM: SUSCEPTIBILITY-WEIGHTED IMAGING IS USEFUL AND PROGNOSIS CAN BE GOOD

We present two cases of cerebral fat embolism. Both patients were 21-years old, male and involved in high impact road traffic collisions with no immediate neurological deficits. Patient A underwent intra-medullary nailing of right tibia/fibular fractures within 12 hours, and had external fixation for bilateral distal femoral fractures. Post-operatively, GCS was 6. Subsequent intracranial MR imaging showed widespread cerebral hypointense punctate foci on SWI (susceptibility-weighted imaging), some with associated restriction on DWI (diffusion-weighted imaging). Despite initial period of coma lasting weeks and inpatient admission over 5 months, he has been discharged to a neuro-rehabilitation unit and continues to show physical and cognitive improvement (MRS score of 3). Patient B underwent intra-medullary nailing for a femoral shaft fracture within 24 hours. Post-operatively, GCS was 9, he developed a petechial rash and became hypoxic. MR brain showed bilateral centrum semiovale DWI restriction, and again, widespread SWI punctate abnormalities. He was discharged within weeks and currently lives at home with his parents (MRS of 2). These cases show the spectrum of radiological abnormalities, the utility of SWI, and highlight that although neurological injury may be severe, there is potential for significant recovery.

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