Optic neuritis with potential for poor outcome.

The Optic Neuritis Treatment Trial previously reported that corticosteroids accelerated visual recovery in optic neuritis (ON) without improving outcome. This finding related largely to multiple sclerosis (MS), and subsequently neurologists tended to await spontaneous recovery in ON. Since then, non-MS cases of ON have been identified with antibodies to aquaporin-4 (AQP4) or myelin oligodendrocyte glycoprotein (MOG). These disorders can closely mimic multiple sclerosis-associated or idiopathic demyelinating optic neuritis (MS/IDON) initially but risk a worse visual outcome. Scrutinising the clinical features and neuroimaging often enables differentiation between MS/IDON and other causes of ON. Early treatment with high-dose corticosteroids is an important determinant of visual outcome in non-MS/IDON. Prompt use of plasma exchange may also save sight. In this review, we contrast the presentations of myelin oligodendrocyte glycoprotein associated optic neuritis (MOG-ON) and aquaporin 4 associated optic neuritis (AQP4-ON) with MS/IDON and provide an approach to acute management while awaiting results of antibody testing.

Is 1H-MR spectroscopy useful as a diagnostic aid in MSA-C?

BACKGROUND: Multiple system atrophy (MSA) is a sporadic adult-onset neurodegenerative disease with a cerebellar subtype where ataxic symptoms predominate (MSA-C) associated with autonomic dysfunction and a grave prognosis. The purpose of this analysis was to identify if cerebellar volumetry and MR spectroscopy obtained as part of routine clinical work up of patients with sporadic ataxia differentiates patients with multiple system atrophy- cerebellar type (MSA-C) from those with sporadic adult-onset ataxia of unknown etiology (SAOA) who's condition follows a more benign course. METHODS: Retrospective comparison was undertaken of 20 clinically probable or possible MSA-C patients, 20 age and sex matched patients with SAOA and 20 healthy control subjects. Single voxel 1H-MR spectroscopy of the cerebellar hemisphere and vermis and volumetric analysis of the cerebellum and brainstem were undertaken on baseline scans, comparing all groups. RESULTS: There was significant reduction in NAA/Cr levels in patients with MSA-C when compared to those with ISA (p = 0.005) and healthy controls (p < 0.001) in both the hemisphere and vermis. Brainstem volume was significantly reduced in MSA-C patients compared to SAOA patients (p < 0.001) and healthy controls (p < 0.001). There was no difference in cerebellar volume between MSA-C patients and SAOA patients. CONCLUSION: This paper demonstrates that at presentation, MSA-C patients have a significant reduction of NAA/Cr in the cerebellum and significant decrease in brainstem volume when compared to SAOA and healthy controls. This is the first study to sucessfully show clinical utility of MR spectroscopy of the cerebellum for differentiating MSA-C from patients with SAOA.

Do Optic Canal Dimensions Measured on CT Influence the Degree of Papilloedema and Visual Dysfunction in Idiopathic Intracranial Hypertension?

A recent study found that increased optic canal area on magnetic resonance imaging was associated with worse papilloedema in idiopathic intracranial hypertension (IIH). We repeated this study using more accurate computerized tomography derived measurements. Optic canal dimensions were measured from 42 IIH patients and 24 controls.  These were compared with papilloedema grade.  There was no correlation between any of the optic canal measurements and papilloedema grade and no significant difference in optic canal measurements between patients and controls. Our results cast doubt on the existing literature regarding the association between optic canal size and the degree of papilloedema in IIH. CT delineates bony anatomy more accurately than MRI and our CT-derived optic canal measurements cast doubt on the existing literature regarding the association between optic canal size and the degree of Papilloedema in IIH.

Brain-injured Survivors of Monochorionic Twin Pregnancies Complicated by Single Intrauterine Death: MR Findings in a Multicenter Study.

Purpose To describe and classify the range of brain injuries present at prenatal, in-utero magnetic resonance (MR) imaging in co-twin survivors of monochorionic (MC) twin pregnancies complicated by single intrauterine death (SIUD). Materials and Methods This retrospective, observational study from six tertiary fetal medicine centers that perform tertiary-level prenatal in-utero MR studies reviewed cases in which prenatal in-utero MR imaging had shown a brain injury in a surviving co-twin of a twin pregnancy with a MC component complicated by SIUD. Results Forty-two surviving MC twins were described. The primary distinction of brain abnormalities was into nonfocal and focal lesions. The nonfocal lesions included periventricular leukomalacia (group 1; two fetuses), generalized encephalomalacia (group 2; nine fetuses), posterior encephalomalacia (group 3; seven fetuses), and bilateral parasagittal and perisylvian injury (group 4; three fetuses). The focal lesions included nonhemorrhagic lesions (group 5; 14 fetuses) and hemorrhagic lesions (group 6; seven fetuses). Focal brain lesions were more likely to be found in the surviving MC pregnancies complicated by twin-twin transfusion syndrome (TTTS) (odds ratio, 2.4; 95% confidence interval: 1.3, 18.5; P = .01) and in fetuses that underwent an obstetric intervention (odds ratio, 2.8; 95% confidence interval: 1.8, 23.6; P = .006). Conclusion Brain injury of the surviving co-twin after SIUD in MC pregnancies is usually of ischemic origin and spares the brainstem and cerebellum. Focal brain lesions are more frequent in pregnancies complicated by TTTS or in those where an intervention has been performed.

A qualitative comparison of arterial spin labelling and dynamic susceptibility contrast MRI in 52 children with a range of neurological conditions.

OBJECTIVE: To assess the usefulness of arterial spin labelling (ASL) compared with dynamic susceptibility contrast (DSC) perfusion MRI for typical paediatric neuroimaging applications at 1.5 T. METHODS: 52 children (age: 4 months-17 years) with a variety of neurological disorders were scanned using three-dimensional ASL and echoplanar imaging DSC sequences. All images were reviewed by an experienced neuroradiologist; image quality was recorded as "good", "acceptable" or "poor" and diagnostic value was noted as being "greater", "similar" or "less" for ASL when compared with DSC. RESULTS: ASL cerebral blood flow (CBF) images were judged to be acceptable in 89% of cases, poor in 11% of cases and good in 0% of cases, while DSC CBF images were acceptable in 88% of cases, poor in 12% of cases and good in 0% of cases. ASL images were judged to have better diagnostic value than DSC images in 28% of cases, about the same in 58% of cases and worse in 14% of cases. CONCLUSION: The results of this study suggest that ASL offers a realistic alternative to DSC in the paediatric setting for the majority of cases encountered in this study. However, there are some situations where DSC outperforms ASL; so, care is required to choose the most appropriate technique for the pathology under investigation. A larger study is required to corroborate these preliminary findings. Advances in knowledge: ASL is a relatively new perfusion imaging technique whose use has not been explored extensively in the paediatric setting. This work is a preliminary study to evaluate its usefulness in paediatric neuroimaging.

Dynamic contrast-enhanced MRI improves accuracy for detecting focal splenic involvement in children and adolescents with Hodgkin disease.

BACKGROUND: Accurate assessment of splenic disease is important for staging Hodgkin lymphoma. OBJECTIVE: The purpose of this study was to assess T2-weighted imaging with and without dynamic contrast-enhanced (DCE) MRI for evaluation of splenic Hodgkin disease. MATERIALS AND METHODS: Thirty-one children with Hodgkin lymphoma underwent whole-body T2-weighted MRI with supplementary DCE splenic imaging, and whole-body PET-CT before and following chemotherapy. Two experienced nuclear medicine physicians derived a PET-CT reference standard for splenic disease, augmented by follow-up imaging. Unaware of the PET-CT, two experienced radiologists independently evaluated MRI exercising a locked sequential read paradigm (T2-weighted then DCE review) and recorded the presence/absence of splenic disease at each stage. Performance of each radiologist was determined prior to and following review of DCE-MRI. Incorrect MRI findings were ascribed to reader (lesion present on MRI but missed by reader) or technical (lesion not present on MRI) error. RESULTS: Seven children had splenic disease. Sensitivity/specificity of both radiologists for the detection of splenic involvement using T2-weighted images alone was 57%/100% and increased to 100%/100% with DCE-MRI. There were three instances of technical error on T2-weighted imaging; all lesions were visible on DCE-MRI. CONCLUSIONS: T2-weighted imaging when complemented by DCE-MRI imaging may improve evaluation of Hodgkin disease splenic involvement.