Tim Jaspan

Neuroimaging: what neuroradiological features distinguish abusive from non-abusive head trauma? A systematic review

Objectives To identify the evidence base behind the neuroradiological features that differentiate abusive head trauma (AHT) from non-abusive head trauma (nAHT). Design Systematic review. Setting Literature search of 14 databases, websites, textbooks, conference abstracts and references (1970–February 2010). Studies had two independent reviews (three if disputed) and critical appraisal. Patients Primary comparative studies of children <11 years old hospitalised with AHT and nAHT diagnosed on CT or MRI. Main outcome measures Neuroradiological features that differentiated AHT from nAHT. Results 21 studies of children predominantly <3 years old were analysed. Subdural haemorrhages (SDH) were significantly associated with AHT (OR 8.2, 95% CI 6.1 to 11). Subarachnoid haemorrhages were seen equally in AHT and nAHT and extradural haemorrhages (EDH) were significantly associated with nAHT (OR for AHT 0.1, 95% CI 0.07 to 0.18). Multiple (OR 6, 95% CI 2.5 to 14.4), interhemispheric (OR 7.9, 95% CI 4.7 to 13), convexity (OR 4.9, 95% CI 1.3 to 19.4) and posterior fossa haemorrhages (OR 2.5, 95% CI 1 to 6) were associated with AHT. Hypoxic-ischaemic injury (HII) (OR 3.7, 95% CI 1.4 to 10) and cerebral oedema (OR 2.2, 95% CI 1.0 to 4.5) were significantly associated with AHT, while focal parenchymal injury was not a discriminatory feature. SDH of low attenuation were more common in AHT than in nAHT. Conclusion Multiple SDH over the convexity, interhemispheric haemorrhages, posterior fossa SDH, HII and cerebral oedema are significantly associated with AHT and should be considered together with clinical features when identifying the condition.

Cerebral contusional tears as a marker of child abuse--detection by cranial sonography

A series of 6 infants subjected to child abuse is presented in whom contusional tears of subcortical white matter were detected during life by intracranial sonography. The sonographic appearances of this highly pathognomonic marker of shaking injury are described for the first time and their significance discussed. On the basis of our experience we suggest that high resolution cranial sonography is an extremely valuable part of the diagnostic work up in cases of suspected non-accidental injury.

Comparison of Magnetic Resonance Angiography With Conventional Angiography in the Detection of Intracranial Aneurysms in Patients Presenting With Subarachnoid Haemorrhage

Thirty-nine patients admitted with proven subarachnoid haemorrhage were imaged both with 3-D time of flight (TOF) magnetic resonance angiography (MRA) and conventional angiography. As the definitive examination, catheter angiography demonstrated 37 aneurysms; ten patients had no aneurysm, the remaining 29 patients had 37 aneurysms. We found the sensitivity of 3-D TOF MRA for the detection of aneurysms to be 81% and specificity to be 100% when the reporting radiologist inspects not only the MIP reconstructions but also the MRA source data and the axial spin-echo images. The investigation is less accurate if all the available imaging data is not considered.

What neuroimaging should be performed in children in whom inflicted brain injury (iBI) is suspected? A systematic review

AIMS To investigate the optimal neuroradiological investigation strategy to identify inflicted brain injury (iBI). MATERIALS AND METHODS A systematic review of studies published between 1970-2008 in any language was conducted, searching 20 databases and four websites, using over 100 keywords/phrases, supplemented by hand-searching of references. All studies underwent two independent reviews (with disagreements adjudicated by a third reviewer) by trained reviewers from paediatrics, paediatric neuroradiology and related disciplines, using standardized critical appraisal tools, and strict inclusion/exclusion criteria. We included primary studies that evaluated the diagnostic yield of magnetic resonance imaging (MRI), in addition to initial computed tomography (CT), or follow-up CT or ultrasound in children with suspected iBI. RESULTS Of the 320 studies reviewed, 18 met the inclusion criteria, reflecting data on 367 children with iBI and 12 were published since 1998. When an MRI was conducted in addition to an abnormal early CT examination, additional information was found in 25% (95% CI: 18.3-33.16%) of children. The additional findings included further subdural haematoma, subarachnoid haemorrhage, shearing injury, ischaemia, and infarction; it also contributed to dating of injuries. Diffusion-weighted imaging (DWI) further enhanced the delineation of ischaemic changes, and assisted in prognosis. Repeat CT studies varied in timing and quality, and none were compared to the addition of an early MRI/DWI. CONCLUSIONS In an acutely ill child, the optimal imaging strategy involves initial CT, followed by early MRI and DWI if early CT examination is abnormal, or there are ongoing clinical concerns. The role of repeat CT imaging, if early MRI is performed, is unclear, as is the place for MRI/DWI if initial CT examination is normal in an otherwise well child.

Problems and pitfalls of 3-D TOF Magnetic resonance angiography of the intracranial circulation

3-D Time of flight (TOF) Magnetic resonance angiography (MRA) is being increasingly adopted as a technique for assessment of the intracranial circulation in neuroradiological practice. We describe our recent experience of 3-D time of flight Magnetic resonance angiography. We describe some of the problems and potential pitfalls that we have experienced employing 3-D TOF MRA in these circumstances, and the diagnostic dilemmas that have arisen. A range of problems have been encountered. When performing 3-D TOF MRA, other phenomena such as sub-acute thrombus and high signal structures may be incorporated into the Maximal Intensity Projection (MIP) reconstruction and masquerade as vascular abnormalities. Interpretation of MIP reconstructions can also be difficult or impossible in the presence of sizeable haematoma. Conversely, vascular structures may not be appreciated because of loss of signal from saturation effects or dephasing due to slow or complex flow. Local susceptibility artefacts, from aneurysm clips or coils, may reduce the signal from vascular structures. Interpretation of 3-D TOF MRA must take account of potential pitfalls which can be minimized by adoption of appropriate imaging and review strategies. This requires careful consideration of MRA source data, the spin-echo axial images as well as the MIP reconstructions.

Shaken baby syndrome

A 35-day-old male infant with presumed shaken baby syndrome is reported. This first born child to mother educated upto middle school and father tailor by occupation was brought from a remote village 180 kms away from JIPMER. Poor feeding, focal clonic seizures were the initial symptoms. The fundus examination revealed fresh preretinal and vitreous hemorrhages. CT Brain showed right sided subdural hemorrhage with subarachnoid extension and midline shift. He had a normal platelet count and coagulation profile. The sensorium deteriorated and infant expired despite adequate ventilatory support.

Central Veins in Brain Lesions Visualized With High-Field Magnetic Resonance Imaging: A Pathologically Specific Diagnostic Biomarker for Inflammatory Demyelination in the Brain

IMPORTANCE There is no single test that is diagnostic for multiple sclerosis (MS), and existing diagnostic criteria are imperfect. This can lead to diagnostic delay. Some patients require multiple (sometimes invasive) investigations, and extensive clinical follow-up to confirm or exclude a diagnosis of MS. A diagnostic biomarker that is pathologically specific for the inflammatory demyelination in MS could overhaul current diagnostic algorithms. OBJECTIVE To prospectively assess the diagnostic value of visualizing central veins in brain lesions with magnetic resonance imaging (MRI) for patients with possible MS for whom the diagnosis is uncertain. DESIGN Prospective longitudinal cohort study. The reference standard is a clinical diagnosis that is arrived at (after a mean follow-up of 26 months) by the treating neurologist with a specialist interest in MS. The 7-T MRI scans were analyzed at baseline, by physicians blinded to the clinical data, for the presence of visible central veins. SETTING Academic MS referral center. PARTICIPANTS A consecutive sample of 29 patients referred with possible MS who had brain lesions detected on clinical MRI scans but whose condition remained undiagnosed despite expert clinical and radiological assessments. EXPOSURE Seven-Tesla MRI using a T2*-weighted sequence. MAIN OUTCOMES AND MEASURES The proportion of patients whose condition was correctly diagnosed as MS or as not MS, using 7-T MRI at study onset, compared with the eventual diagnosis reached by treating physicians blinded to the result of the MRI scan. RESULTS Of the 29 patients enrolled and scanned using 7-T MRI, so far 22 have received a clinical diagnosis. All 13 patients whose condition was eventually diagnosed as MS had central veins visible in the majority of brain lesions at baseline. All 9 patients whose condition was eventually not diagnosed as MS had central veins visible in a minority of lesions. CONCLUSIONS AND RELEVANCE In our study, T2*-weighted 7-T MRI had 100% positive and negative predictive value for the diagnosis of MS. Clinical application of this technique could improve existing diagnostic algorithms.

Neuro-endoscopic third ventriculostomy: Evaluation with magnetic resonance imaging

We have performed a prospective study of the use of magnetic resonance (MR) imaging in 14 patients undergoing neuro-endoscopic third ventriculostomy. MR imaging was undertaken prior to the endoscopy and serial studies were carried out after the procedure. MR imaging provides important information concerning the morphology of the third ventricle and allows the identification of an appropriate puncture site in the floor of the third ventricle. In particular, the relationship of the third ventricular floor to the basilar artery is well demonstrated. Following an endoscopic septostomy, MR imaging allows visualisation of any change in ventricular size. A cerebro-spinal fluid (CSF) flow void in the anterior inferior third ventricle, sometimes extending into the suprasellar cisterns was frequently demonstrated and this was found to be a more constant feature than reduction in ventricular size. MR imaging provides an indispensable tool for both planning and follow-up of endoscopic third ventriculostomy.

Radiological classification of optic pathway gliomas: experience of a modified functional classification system

Optic pathway gliomas (OPGs) in childhood are associated with neurofibromatosis type 1 (NF1) and since 1958 have been classified anatomically using the Dodge classification (DC). MR scanning permits a more detailed anatomical description than can be classified by this historical system. A modified Dodge classification (MDC) has been applied to MRI scans from a cohort of 72 patients (36.1% NF1-positive) from 4 centres participating in an international clinical trial. The MDC was feasible, applicable and more detailed than the original DC. NF1-positive cases more commonly involved both optic nerves (p = 0.021) and other multiple locations (p = 0.001). NF1-negative tumours more commonly involved the central chiasm (p = 0.005) and hypothalamus (p = 0.003). Fewer hypothalamus-positive tumours were associated with optic nerve involvement (p = 0.009), whereas more were associated with central chiasm involvement (p<0.001). From diagnosis to follow-up, there was concordance between DC and MDC in 51/72 cases (70.8%). The MDC is therefore proposed for use in clinical trials of new treatments for OPGs.

The 'unified hypothesis' of Geddes et al. is not supported by the data.

Inflicted head injury to the developing brain frequently results in serious disability. The pathogenesis of the neuraxial and ocular findings in infants believed to have suffered inflicted head injury remains the subject of considerable debate. Recent neuropathology studies of fatal cases of inflicted head injury and of a foetal/perinatal non-traumatic model have led to the proposal that there is a ‘unified hypothesis’, the essential feature of which is hypoxic brain swelling secondary to cervicomedullary injury. It has been suggested that less than violent forces may be involved and even that some cases may not be due to trauma at all. The purpose of this paper is to provide a critical review of the data upon which these suppositions are based on a background of what is already known. It is submitted that there are serious flaws in the methodology; the conclusions reached cannot logically be drawn from the data; and the ‘unified hypothesis’ is not supported by the evidence. On the basis of the data presented, it is also difficult to sustain the secondary hypothesis purporting to describe a minority cohort with ‘infantile encephalopathy with subdural and retinal bleeding’ of non-traumatic causation.