Review of standard paediatric neuroradiology MRI protocols from 12 UK tertiary paediatric hospitals: is there much variation between centres?

AIM: To investigate how magnetic resonance imaging (MRI) examinations are protocolled in tertiary paediatric neuroradiology centres around the UK for some of the more common presentations encountered in paediatric neuroradiology, and to identify any variations of note. MATERIALS AND METHODS: All 19 UK tertiary paediatric neuroradiology centres registered with the British Society of Neuroradiologists-Paediatric Group were contacted and asked if they could provide a copy of their standard MRI protocols. Twelve responded (63%) and 10 of the more common presentations were selected and the standard acquired sequences obtained at each participating centre were compared. Where available the collated protocols were also compared against current published guidance. RESULTS: The basic sequences carried out by centres around the UK are similar; however, there are lots of variations overall. The only standardised protocol currently being implemented nationally in paediatric imaging is that for brain tumours. Otherwise, chosen protocols are generally dependent on the preferences and technical capabilities of individual centres. Suggested published protocols also exist for non-accidental injury (NAI), multiple sclerosis, epilepsy, and head and neck imaging. CONCLUSIONS: The differences in MRI protocolling depend in part on technical capabilities and in part on the experience and preferences of the paediatric neuroradiologists at each centre. For most presentations, there is no consensus as to what constitutes the perfect protocol. The present results will be useful for specialist centres who may wish to review their current protocols, and for more generalist centres to use as a reference to guide their MRI protocolling.

Electron beam evaporation of superconductor-ferromagnet heterostructures.

We report on the electronic and magnetic properties of superconductor-ferromagnet heterostructures fabricated by electron beam evaporation on to unheated thermally oxidised Si substrates. Polycrystalline Nb thin films (5 to 50 nm thick) were shown to possess reliably high superconducting critical temperatures ([Formula: see text]), which correlate well with the residual resistivity ratio (RRR) of the film. These properties improved during ex-situ annealing, resulting in [Formula: see text] and [Formula: see text]RRR increases of up 2.2 K ([Formula: see text] 40% of the pre-annealed [Formula: see text]) and 0.8 ([Formula: see text] 60% of the pre-annealed RRR) respectively. Nb/Pt/Co/Pt heterostructures showed substantial perpendicular anisotropy in the ultrathin limit (≤ 2.5 nm), even in the extreme limit of Pt(0.8 nm)/Co(1 nm)/Pt(0.6 nm). These results point to the use of electron beam evaporation as route to line-of-sight deposited, low-thickness, high quality Nb-based superspintronic multilayers.

The role of MRI and CT of the brain in first episodes of psychosis and behavioural abnormality.

AIM: To investigate whether computed tomography (CT)/magnetic resonance imaging (MRI) brain imaging is associated with detection of structural causes of a first episode of psychosis (FEP) or first episode of behavioural abnormality (FEB) in the paediatric population, as this has not been previously documented in the literature. MATERIALS AND METHODS: Individuals with FEP/FEB but no neurological signs referred to a tertiary children's centre for cerebral MRI or CT were reviewed retrospectively. Individuals were evaluated independently with one technique (CT or MRI) only. RESULTS: Thirty-four consecutive cerebral MRI and six consecutive CT examinations were identified between 2017 and 2020. No patients were identified as having an organic cause for the psychosis at MRI or CT. Four patients (9%) had incidental findings on MRI, unrelated to the psychosis, such as prominent perivascular spaces, hypoplastic transverse sinus, and sinonasal mucosal wall thickening. No abnormal findings were seen on CT. There was therefore no obvious difference between MRI and CT imaging in detecting organic disease potentially responsible for FEP. CONCLUSION: Routine structural MRI or CT of the brain is unlikely to reveal disease leading to a significant change in management. MRI demonstrated only a few incidental findings, unrelated to the child's clinical history. Therefore, routine brain structural imaging of FEP/FEB in paediatric patients without focal neurology may not be routinely required. If imaging is requested, then there is no significant difference between CT and MRI in detecting clinically significant lesions.

T2 prolongation in the cerebellar vermis on prenatal MRI of fetuses with Chiari 2 malformations.

AIM: To describe a new finding in fetuses with Chiari 2 malformations recognised at in utero (iu) magnetic resonance imaging (MRI), specifically T2 prolongation (high signal) in the cerebellar vermis. MATERIALS AND METHODS: This was a prospective observational study of iuMRI studies performed at two time points on 20 fetuses with Chiari 2 malformations and 10 control fetuses at the same time points. High T2 signal in the cerebellar vermis was noted and correlated with posterior fossa dimensions was assessed. RESULTS: High T2 signal in the cerebellar vermis was found in over half of the fetuses with a Chiari 2 malformation, but was not correlated with the degree of reduction in size of the bony posterior fossa. CONCLUSION: The present findings suggest that abnormal high T2 signal in the cerebellum is common in fetuses with Chiari 2 malformations and although the cause of the signal change is not known at present it may represent vasogenic oedema as a result of restricted venous drainage.

A pictorial review of imaging in paediatric stroke.

Stroke is recognised as an important disease in adults. Paediatric stroke is less understood, yet still an important cause of morbidity and mortality, with an incidence of 5 per 100 000 children and is one of the top 10 leading causes of death in children. In adults the vast majority of strokes are ischaemic, whereas in children haemorrhage makes up half the cases. The incidence of neonatal stroke is much higher, at up to 45 per 100 000 population; however, the underlying causes are less understood. This paper acts as a guide to the different causes of stroke with the key differences on imaging discussed.

Paediatric post-septal and pre-septal cellulitis: 10 years' experience at a tertiary-level children's hospital.

OBJECTIVE: To assess the incidence and complications of pre-septal (pre-SC) and post-septal (post-SC) cellulitis over 10 years. Pre-SC and post-SC are also known as periorbital and orbital cellulitis, respectively. METHODS: Retrospective analysis of CT scans. Data included the presence of pre-SC and post-SC, paranasal sinus disease (PNS) and complications. RESULTS: Among 125 patients scanned for these suspected diagnoses, 67 had both pre-SC and post-SC, 37 had pre-SC and 4 had post-SC; there were 17 normal scans. 110 patients had PNS. 68/71 (96%) patients with post-SC had PNS. Post-SC complications included orbital and/or subperiosteal abscess (50/71: 30 medial orbital, 10 superomedial, 3 lateral, 2 anteromedial, 2 inferomedial, 1 superior, 1 anterosuperior and 1 not specified), cavernous sinus thrombosis (CST) (1), superior ophthalmic vein (SOV) thrombosis (4) and subdural frontal empyema (2); 1 patient had SOV and CST and subdural empyema. CONCLUSION: 71/125 (57%) patients had post-SC. 50/125 (40%) patients imaged for pre-SC/post-SC had orbital abscess; 44/50 (88%) of these involved the medial orbit. Patients can develop solely superior or inferior abscesses that are difficult to identify by axial imaging alone, hence coronal reformatted imaging is essential. 5/125 (4%) patients developed major complications (SOV/CST/empyema), hence imaging review of the head and cavernous sinus region is essential. A diagnosis of post-SC on CT should alert the radiologist because this diagnosis can be associated with an increased incidence (5/71, 7%) of complications. ADVANCES IN KNOWLEDGE: We recommend that all patients with a suspected diagnosis of post-SC should undergo CT scan (post-contrast orbits and post-contrast head, with multiplanar reformats and a careful review of the SOV and the cavernous sinus). Particular attention should be paid to exclude intracranial complications including subdural empyema and cerebral abscess. As soon as a diagnosis of post-SC is made, in addition to informing the referring clinical team, urgent opinion should be sought from ear, nose and throat (ENT), neurology and ophthalmology with a view to urgently drain of the paranasal sinuses`.

CT of the neonatal head.

Computed tomography (CT) is used less often than other techniques on neonatal units. However, in the acute setting, CT can be invaluable in diagnosing or excluding potentially life-threatening conditions and guiding initial management in neonates. Common indications for scanning include trauma, suspected non-accidental injury, infection, or an acute hypoxic or metabolic event. The aim of this review is to provide an overview of the normal neonatal head at CT and compare this to the common pathological abnormalities. Several key features of each condition will be highlighted. It is important to note that some pathological conditions can have overlapping features at CT and, therefore, the clinical history and additional investigations are also of key importance in determining the diagnosis.

Management of isolated syringomyelia in the paediatric population--a review of imaging and follow-up in a single centre.

OBJECTIVE: To assess the natural history of isolated syringomyelia in children. METHODS: MRI reports from February 2007 to August 2011 mentioning syrinx were identified on Sheffield Children's PACS database. Scans with syringes having an AP diameter of > 1 mm and extending over at least two vertebral bodies were reviewed. Patients with an identifiable cause such as a Chiari malformation were then excluded. RESULTS: Thirty-nine patients were included with a mean age at diagnosis of 10.6 years. The average syrinx AP diameter was 3.30 mm. The rostrocaudal length of the syringes varied between 2 and 19 vertebral bodies. Twenty-seven out of 39 syringes were thoracic in origin. There were 3 and 6 syringes involving the cervicothoracic and thoracolumbar regions, respectively, with 3 involving the cervical area only. Eleven out of 39 (Group I) patients were found "incidentally" during work-up for adolescent idiopathic scoliosis and these were considered as a separate group. These patients did not have any significant symptoms and were discharged following their scoliosis correction surgery. Syrinx was incidental in 14 further patients (Group II). Of the 14 patients, 11 remained asymptomatic with no change in syrinx morphology throughout follow up. Of the 14 patients, 3 were lost to follow-up. Of the 39 patients, 14 (Group III) presented with progressive back pain without any obvious clinical cause. Of the 14, 10 either improved or remained the same. Of the 14 patients, 3 underwent lumbar puncture, 1/14 having myelography. All 4/14 patients reported significant pain reduction on follow up following intervention. CONCLUSION: Idiopathic syrinx is a benign pathology, which can be managed expectantly. Most cases remain stable or improve over time. In a small minority who have progressive back pain, we have found that lumbar puncture may be helpful in reducing symptoms.

Neuro-ophthalmological Complications of Chronic Inflammatory Demyelinating Polyradiculoneuropathy.

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) can lead to prominent nerve hypertrophy, which can mimic other forms of neuropathy radiologically. Neuro-ophthalmological complications can also occur in CIDP, either at presentation or chronically in the disorder. This can also cause diagnostic difficulties. We report three cases of neuro-ophthalmological complications of CIDP: two cases of papilloedema and one case of proptosis. In all three cases cranial nerve hypertrophy was present. CIDP should be considered in neuro-ophthalmological presentations associated with cranial/spinal nerve root hypertrophy.

MRI protocols for imaging paediatric brain tumours.

AIMS: To establish whether paediatric centres within the Children's Cancer and Leukaemia Group (CCLG) network employ magnetic resonance imaging (MRI) protocols for brain tumours according to the revised guidance. MATERIALS AND METHODS: Questionnaires were sent to both consultants and superintendent radiographers in the 21 centres within the CCLG network that perform MRI on paediatric brain tumour patients. Information was requested as to whether the centre had a protocol for imaging paediatric brain tumours, which sequences were performed, and whether these were used by all consultants. RESULTS: Twenty-seven completed questionnaires out of the 42 sent were returned, which included responses from 17 of the 21 UK centres. The majority of centres had a protocol for MRI of paediatric brain tumours at all stages of treatment. The standardized CCLG MRI sequences were incorporated in full at only five of the 17 centres. CONCLUSION: The standard sequences of the CCLG brain imaging protocol are poorly adhered to nationally. Further awareness of the revised protocol is needed, with improved access to the guidelines for non-CCLG members on the CCLG and Royal college of Radiologists website.

3.0 T MRI of 2000 consecutive patients with localisation-related epilepsy.

OBJECTIVES: Clinical guidelines suggest that all patients diagnosed with localised seizures should be investigated with MRI to identify any epileptogenic structural lesions, as these patients may benefit from surgical resection. There is growing impetus to use higher field strength scanners to image such patients, as some evidence suggests that they improve detection rates. We set out to review the detection rate of radiological abnormalities found by imaging patients with localised seizures using a high-resolution 3.0 T epilepsy protocol. METHODS: Data were reviewed from 2000 consecutive adult patients with localisation-related epilepsy referred between January 2005 and February 2011, and imaged at 3.0 T using a standard epilepsy protocol. RESULTS: An abnormality likely to be related to seizure activity was identified in 403/2000 (20.2%) patients, with mesial temporal sclerosis diagnosed in 211 patients. 313/2000 (15.6%) had lesions potentially amenable to surgery. Abnormalities thought unrelated to seizure activity were found in 324/2000 (16.1%), with 8.9% having evidence of ischaemic disease. CONCLUSIONS: Since the introduction of the then National Institute for Clinical Excellence guidelines in 2004, the detection rate of significant pathology using a dedicated 3.0 T epilepsy protocol has not fallen, despite the increased numbers of patients being imaged. This is the largest study of epilepsy imaging at 3.0 T to date and highlights the detection rates of significant pathology in a clinical setting using a high-strength magnet. The prevalence of ischaemic disease in this population is significantly higher than first thought, and may not be incidental, as is often reported.

Neuroimaging in non-accidental head injury in children: an important element of assessment.

Head injury from physical abuse is unfortunately a common occurrence in our society. It is a major cause of mortality and long-term physical and psychological disability in children. Diagnosis of non-accidental head injury may be difficult, as most infants present with non-specific clinical findings and without external signs of trauma. Neuroimaging plays a fundamental role both for medical management and medicolegal aspects of child abuse. It is therefore imperative for the radiologist to promptly recognise the radiological findings of various forms of non-accidental head injury to render a more accurate opinion. A standardised imaging protocol and good communication between professionals are essential for optimum management.

The encephalopathic child.

Encephalopathy is a common paediatric emergency associated with a high risk of morbidity, mortality and long term neurodevelopmental delay in survivors. Prompt diagnosis of the cause of encephalopathy enables the paediatrician to deliver specific medical or surgical treatment that will facilitate a better short and long term outcome. Diagnostic imaging plays a pivotal role in diagnosis. Encephalopathy has many causes. The differential diagnosis includes non accidental injury, trauma, metabolic syndromes, meningo-encephalitis, toxins, hypoxia, demyelination, stroke, haemorrhage and tumours. We describe an approach that helps us formulate an imaging strategy using US, CT and MRI that facilitates patient care.

Development, validation and field application of an RNA-based growth index in juvenile plaice Pleuronectes platessa.

A general mechanism relating RNA concentration and growth rate is derived from four physiological assumptions and developed into a growth index for juvenile plaice Pleuronectes platessa. The index describing instantaneous growth rates (G, day⁻¹) in the laboratory with the lowest Akaike information criterion with small-sample bias adjustment was a function of RNA concentration (R, g(RNA)g⁻¹(wet mass)), temperature (T, ° K), body mass (M, g) and DNA concentration (D, g(DNA)g⁻¹(wet mass)): G = ß0 + ß(R) R + ß(T)T + ß(T2)T² + ß(M)M + ß(D)D + ß(RT)RT. RNA concentration began to respond to changes in feeding conditions within 8 days, suggesting that the index reflects growth rate in the short-term. Furthermore, the index distinguished between rapid growth and negative growth of juvenile P. platessa measured directly in laboratory and field enclosures, respectively. An application of the RNA-based growth index at two beaches on the west coast of Scotland suggested that the growth of juvenile P. platessa varies considerably in space and time and is submaximum in late summer.

Killer whales (Orcinus orca) feeding on schooling herring (Clupea harengus) using underwater tail-slaps: kinematic analyses of field observations.

Killer whales (Orcinus orca) feeding on herring (Clupea harengus) in a fjord in northern Norway were observed using underwater video. The whales cooperatively herded herring into tight schools close to the surface. During herding and feeding, killer whales swam around and under a school of herring, periodically lunging at it and stunning the herring by slapping them with the underside of their flukes while completely submerged. The kinematics of tail-slapping were analysed in detail. Tail-slaps were made up of a biphasic behaviour consisting of two phases with opposite angles of attack, a preparatory phase (negative angles of attack) and a slap phase (positive angles of attack). During the slap phase, the mean maximum angle of attack of the flukes was 47 degrees. The maximum speed of the flukes, measured at the notch, increased with whale length (L(w)) and was 2.2 L(w )s(-)(1), while the maximum acceleration of the flukes was size-independent and was 48 m s(-)(2). When killer whales slapped the herring successfully, disoriented herring appeared on the video at approximately the time of maximum fluke velocity, in synchrony with a loud noise. This noise was not heard when the tail-slaps 'missed' the target, suggesting that the herring were stunned by physical contact. Killer whales then ate the stunned herring one by one. Of the tail-slaps observed, 61 % were preceded by lunges into the school. We suggest that lunging was aimed at directing the school rather than at capturing the herring, since it occurred at a relatively low speed and there were no observations of the killer whales attempting to capture the herring during lunging behaviour. Given the high performance of the tail-slaps in terms of speed and acceleration, we suggest that tail-slapping by killer whales is a more efficient strategy of prey capture than whole-body attacks, since acceleration and manoeuvrability are likely to be poor in such large vertebrates.

Predicting the rate of physician-accepted interventions by hospital pharmacists in the United Kingdom.

Pharmacists' clinical interventions in a group of British hospitals were counted, and a model to determine factors that affected the intervention rate was developed. All pharmacists who visited patient wards in 27 acute care hospitals recorded their daily ward visits and their clinical interventions during five consecutive days (Monday through Friday) in June 1993. An intervention was defined as any recommendation made with the intent of changing drug treatment. Mixed-model Poisson regression was used to try to explain variations in the intervention rate, defined as the number of physician-accepted interventions divided by the number of occupied-bed days. Possible predictors of intervention rate considered were characteristics of the hospitals, the wards, and the pharmacists. During the study period, 248 pharmacists visited 10,478 beds and proposed 3,501 interventions. Of these interventions, 3371 were accepted, 56 were rejected, and 74 were unresolved. The most frequent reasons for the interventions involved the dose (29%), the need for therapy (21%), the choice of drug (14%), and the route (12%). Ward type, pharmacist grade, and the total time the pharmacist spent on the wards were significant predictors of the intervention rate. To validate the model, data were collected during the same period in 1994; the model predicted the number of interventions within 1 of the actual number in 82% of cases. In a model explaining the factors that affected the rate of physician-accepted pharmacist interventions in acute care hospitals in the United Kingdom, ward type, pharmacist grade, and total time spent on the ward by the pharmacist were significant predictors of the intervention rate.

What a drag it is getting cold: partitioning the physical and physiological effects of temperature on fish swimming

The influence of temperature-induced changes in water viscosity on the swimming performance and kinematics of larval Atlantic herring (Clupea harengus) was examined using high-speed video recording. The physical effects of viscosity were measured separately from the physiological (Q10) effects of temperature by increasing the viscosity using methyl cellulose. Voluntary swimming speeds of large larvae (18.2 mm total length) were characterized by Reynolds numbers based on length (ReL) between 100 and 500 and varied with temperature and viscosity. Speeds of small larvae (9.6 mm) at ReL between 25 and 125 were strongly affected by viscosity, but virtually unaffected by temperature at equal viscosities. Speeds of large larvae were modulated by transverse tail speed. Small (viscosity-dominated) larvae altered both transverse tail speed and tail amplitude to vary their swimming speed. Stride lengths for both sizes of larvae followed predictions for viscous-regime swimming until ReL>450. The combined data suggest that the viscous hydrodynamic regime for larval herring extends to at least ReL=300 and that viscosity could be important up to ReL of approximately 450. Because the physical effects of viscosity supplement the physiological effects of temperature on locomotor performance (when ReL is below approximately 300), indices such as Q10 can greatly overestimate the dependence of physiological processes on temperature, as demonstrated by an example.

Dietary deficiency of docosahexaenoic acid impairs vision at low light intensities in juvenile herring (Clupea harengus L.).

In the retina of herring (Clupea harengus L.), rods are recruited from about 8 wk after hatching, and from this time there is a linear relationship between the number of rods in the photoreceptor cell population and the content of di22:6n-3 molecular species of phospholipids. Juvenile herring were reared from four weeks' post-hatching for 15 wk on either Artemia nauplii deficient in 22:6n-3 or on enriched Artemia nauplii containing 4.3% 22:6n-3. The visual performance of the fish was then determined at three light intensities (0.01, 0.1, and 1.0 lux) by observing their frequency of striking at live Artemia nauplii using infrared video recording. Herring reared on the diet containing no 22:6n-3 were less active predators, especially at the lowest light intensity where very few strikes were observed. The eyes of these fish contained greatly reduced levels of di22:6n-3 molecular species of total phospholipid, 2.1% vs. 12.0% in fish supplemented with 22:6n-3. The contribution of saturated and monounsaturated fatty acids in the molecular species of phosphatidylethanolamine (PE), phosphatidylserine (PS), and phosphatidylcholine (PC) was virtually unchanged, while 20:5n-3 and 22:5n-3 largely replaced 22:6n-3. There was an almost complete disappearance of di22:6n-3 PC, while the amounts of di22:6n-3 PE and PS fell by 18.1 and 20.6% to 2.7 and 7.6%, respectively. The dipolyunsaturated molecular species di20:5n-3, 20:5n-3/22:5n-3, and di22:5n-3 made up a substantial part of the deficit. We conclude that a dietary deficiency of 22:6n-3 during the period early in rod development impairs visual performance such that the fish can no longer feed at low light intensities.

Ward pharmacy: a foundation for prescribing audit?

OBJECTIVES: To determine the extent and nature of prescription monitoring incidents by hospital pharmacists and to derive a performance indicator to allow prescription monitoring to be compared among hospitals in North West Thames region. DESIGN: Survey of all self recorded prescription monitoring incidents for one week in June 1990. SETTING: All (31) acute hospitals in the region with pharmacy departments on site, covering 10,337 beds. SUBJECTS: 210 pharmacists. MAIN MEASURES: Number of prescription monitoring incidents recorded, their nature, and outcome; a performance indicator of prescription monitoring (incidents/100 beds/week) and its variation according to specialty and site. RESULTS: 3273 prescription monitoring incidents were recorded (median 89 per hospital, range 3-301), the most common being related to the dose and frequency of administration of the drug (933 incidents, 29%). These incidents led to alterations of prescriptions on 1611 occasions; the pharmacist's advice was rejected on 81. The greatest number of prescription monitoring incidents/100 beds/week by specialty was recorded for intensive therapy units (median 75); the medians for medicine and surgery were 32 and 21 respectively. This performance indicator varied 20-fold when analysed by site, values ranging from 3.6 to 82.1 (median 29.8). CONCLUSIONS: Hospital pharmacists play a large part in monitoring and improving prescribing, and most of their interventions are related to the basics of prescribing. They therefore have a role in medical audit, working with clinicians to identify prescribing problems, and to set standards and monitor practice. A performance indicator of prescription monitoring incidents/100 beds/week allows comparison of pharmacists' activities among sites and may be a valuable tool in auditing them.