Evolution of the intracranial features of congenital cytomegalovirus on MRI.

AIM: To describe the evolution of the intracranial features of congenital cytomegalovirus (cCMV) on magnetic resonance imaging (MRI). MATERIALS AND METHODS: Sixteen infants with polymerase chain reaction (PCR)-confirmed cCMV who had undergone at least two MRI examinations of the brain were identified. Two paediatric neuroradiologists reviewed the baseline studies retrospectively for intracranial features of cCMV, including white matter signal abnormalities, subependymal cysts, malformations of cortical development, and intracranial calcification. The subsequent MRI studies were then reviewed and directly compared to the baseline examinations. RESULTS: White matter signal abnormalities were seen on all 16 baseline studies (100%); these persisted on all subsequent examinations but were patchier, more focal, and associated with an interval reduction in white matter volume. Subependymal cysts were present on 11 (69%) of the baseline scans; these almost universally regressed (in 10 of the 11 cases [91%]), with no new cysts appreciable on subsequent imaging. Malformations of cortical development, exclusively in the form of polymicrogyria, were seen in six (38%) patients and persisted, unchanged, on subsequent imaging. Intracranial calcification was seen in a minority of baseline studies (4 [25%]) and remained stable on subsequent scans. CONCLUSION: Children with cCMV who present later in life without an established or suspected underlying pathology can pose a challenge to the assessing radiologist. The radiological sequelae of cCMV can be non-specific; in some cases, white matter signal abnormalities and focal loss of white matter volume may be the only intracranial features. It is therefore important that radiologists are aware of cCMV as a potential differential for these findings.

Diagnostic analysis of baseline brain MRI features in infants with congenital cytomegalovirus infection: a simplified scoring system.

AIM: To characterise the magnetic resonance imaging (MRI) features of infants with congenital cytomegalovirus (CMV) and categorise those into a simplified MRI scoring system. MATERIALS AND METHODS: Three neuroradiologists reviewed the examinations of 71 infants retrospectively and scored for the presence of a white matter signal abnormality and structural lesion and each MRI was given a score of 0, 1, 2, or 3 for normal, structural abnormality alone, white matter abnormality alone, white matter abnormality plus structural lesion, respectively. Imaging features were outlines according to symptomatology. Chi-square and Spearman's rho were used to test relationships between MRI features and viral loads and MRI score/symptomatic disease respectively. Cohen's Kappa coefficient was used to assess interobserver agreement. RESULTS: Of the 49 abnormal studies, 40% (n=20) were seen in asymptomatic infants. The commonest finding was white matter signal abnormality, followed by cyst formation and polymicrogyria (86%, n=42; 71%, n=35; and 33%, n=16, respectively). Cysts were significantly positively correlated with white matter abnormalities and polymicrogyria. On the MRI score, 31%, 10%, 15%, and 44% obtained a score of 0, 1, 2, and 3, respectively; the MRI score was positively correlated with log-transformed viral loads. Interobserver agreement for the presence of white matter signal abnormality, cyst formation, malformations of cortical development (MCD), and global MRI score was excellent (k = 0.82, 0.94, 0.96, and 0.86, respectively). CONCLUSION: Baseline MRI provides information valuable for treatment decisions, especially in "asymptomatic" infants. The simplified scoring system is easier to use, incorporating solely the imaging findings that are anticipated to have an effect on clinical outcome.

Characterisation of isocitrate dehydrogenase gene mutant WHO grade 2 and 3 gliomas: MRI predictors of 1p/19q co-deletion and tumour grade.

AIM: To identify imaging predictors of molecular subtype and tumour grade in patients with isocitrate dehydrogenase (IDH) gene mutant (IDHmut) World Health Organization (WHO) grade 2 or 3 gliomas. MATERIALS AND METHODS: Patients with histologically confirmed WHO grade 2 or 3 IDHmut gliomas between 2016 and 2019 were included in the study. Magnetic resonance imaging (MRI) images were evaluated for the presence or absence of potential imaging predictors of tumour subtype, such as T2/fluid attenuated inversion recovery (FLAIR) signal match, and these factors were examined using regression analysis. On perfusion imaging, the maximum relative cerebral blood volume (rCBVmax) was evaluated as a potential predictor of tumour grade. The performance of two experienced neuroradiologists in correctly predicting tumour type on MRI was evaluated. RESULTS: Eighty-five patients were included in the study. The presence of T2/FLAIR signal match >50% of tumour volume (p<0.01) and intratumoural susceptibility (p=0.02) were independent predictors of 1p/19q co-deletion. Mean rCBV max was significantly higher in WHO grade 3 astrocytomas (p=0.04) than WHO grade 2 astrocytomas. The consensus prediction of 1p/19q co-deletion status by two neuroradiologists of tumour was 95% sensitive and 86% specific. CONCLUSION: The presence of matched T2/FLAIR signal could be used to identify tumour subtype when biopsy is inconclusive or genetic analysis is unavailable. rCBVmax predicted astrocytoma grade. Experienced neuroradiologists predict tumour subtype with good sensitivity and specificity.

Autoimmune cortical encephalitis in two children with anti-myelin oligodendrocyte glycoprotein (MOG) antibody.

PURPOSE: Anti-myelin oligodendrocyte glycoprotein antibodies (anti-MOG), directed against a component of the myelin sheath, are sometimes detected in the blood or cerebrospinal fluid (CSF) of patients with acute demyelinating conditions. Cortical encephalitic presentations in anti-MOG-antibody-positive patients are recognized but rare, and few pediatric cases have been described. METHODS: We describe clinical, biochemical, and MRI findings in two children presenting with generalized seizures due to cortical encephalitis, and review potential underlying immunological processes. RESULTS: In both patients, anti-MOG antibodies were detected. Both underwent MRI scans which demonstrated bilateral cortical swelling and T2/fluid-attenuated inversion recovery (FLAIR) hyperintensity with corresponding regions of reduced diffusion. CONCLUSION: Early detection of anti-MOG antibodies in patients with a similar presentation and imaging features would enable rapid institution of appropriate treatment, and potentially reduce the need for invasive diagnostic procedures such as brain biopsy.

Is it not time for international guidelines to combat congenital cytomegalovirus infection? A review of central nervous system manifestations.

Cytomegalovirus (CMV) is the most commonly transmitted virus in utero with a prevalence of up to 1.5%. The infection has potentially debilitating and devastating consequences for the infected fetus, being a leading cause for neurological disability worldwide. Once acquired, it often goes undetected with only an assumed 10% of infected neonates displaying the classic clinical or imaging features. Viral DNA polymerase chain reaction (PCR) of saliva or urine obtained within the first 21 days of life is required to make the diagnosis. As the majority of infected neonates are initially asymptomatic, diagnosis is often delayed. An abnormal routine neonatal hearing test and characteristic antenatal cranial ultrasound imaging findings may raise the suspicion of congenital CMV (cCMV) in the asymptomatic group. Ultimately, the aim is to facilitate early diagnosis and timely treatment. In this article, we highlight diagnostic and treatment challenges of the commonest congenital infection, we present the current available central nervous system imaging severity grading systems, and highlight the need for an internationally agreed diagnostic grading system that can aid treatment decision-making.

Tissue- and column-specific measurements from multi-parameter mapping of the human cervical spinal cord at 3 T.

The aim of this study was to quantify a range of MR parameters [apparent proton density, longitudinal relaxation time T1, magnetisation transfer (MT) ratio, MT saturation (which represents the additional percentage MT saturation of the longitudinal magnetisation caused by a single MT pulse) and apparent transverse relaxation rate R2*] in the white matter columns and grey matter of the healthy cervical spinal cord. The cervical cords of 13 healthy volunteers were scanned at 3 T using a protocol optimised for multi-parameter mapping. Intra-subject co-registration was performed using linear registration, and tissue- and column-specific parameter values were calculated. Cervical cord parameter values measured from levels C1-C5 in 13 subjects are: apparent proton density, 4822 ± 718 a.u.; MT ratio, 40.4 ± 1.53 p.u.; MT saturation, 1.40 ± 0.12 p.u.; T1 = 1848 ± 143 ms; R2* = 22.6 ± 1.53 s(-1). Inter-subject coefficients of variation were low in both the cervical cord and tissue- and column-specific measurements, illustrating the potential of this method for the investigation of changes in these parameters caused by pathology. In summary, an optimised cervical cord multi-parameter mapping protocol was developed, enabling tissue- and column-specific measurements to be made. This technique has the potential to provide insight into the pathological processes occurring in the cervical cord affected by neurological disorders.

Four-part proximal humeral fractures: diagnosis with the 'sunset' sign on anteroposterior radiograph.

INTRODUCTION: Four-part proximal humeral fractures require surgical intervention. However, they can be difficult to diagnose in radiological images. We aim to define a new, easily recognisable, radiological sign as a predictor of four-part fracture of the proximal humerus in a plain anteroposterior radiograph of the shoulder. PATIENTS AND METHODS: We describe our 'sunset' sign as 'articular surface of humeral head pointing away from the glenoid and tilted upwards, in the presence of a displaced greater tuberosity fracture'. We postulate that a patient with proximal humerus fracture showing this sign has four-part fracture until proven otherwise. Between 2002 and 2006, 80 consecutive patients had surgical treatment of their proximal humeral fractures in our unit. Pre-operative radiographs and operative notes of 79 patients were evaluated independently by three blinded observers. The presence of 'sunset' sign was recorded. Findings were then correlated with the operative diagnoses to confirm whether they were four-part fractures or not. With 95% confidence interval, we calculated the sensitivity, specificity, positive and negative predictive values for our diagnostic sign. RESULTS: Of 79 patients, 30 displayed 'sunset' sign in their pre-operative radiograph. Of these, 28 had confirmed four-part fractures operatively. The positive predictive value of 'sunset' sign was 93%. The specificity and sensitivity were 95% and 78%, respectively. The sensitivity was affected by eight patients with four-part fractures with displaced articular head fragment which had dropped either medially or posteriorly. CONCLUSIONS: These results suggest that, in patients with proximal humeral fractures, the presence of 'sunset' sign in the anteroposterior radiograph is a reliable indicator of four-part fracture.