Search

MRS can provide high accuracy in the diagnosis of childhood brain tumours when combined with machine learning. A feature selection method such as principal component analysis is commonly used to reduce the dimensionality of metabolite profiles prior to classification. However, an alternative approach of identifying the optimal set of metabolites has not been fully evaluated, possibly due to the challenges of defining this for a multi-class problem. This study aims to investigate metabolite selection from in vivo MRS for childhood brain tumour classification. Multi-site 1.5 T and 3 T cohorts of patients with a brain tumour and histological diagnosis of ependymoma, medulloblastoma and pilocytic astrocytoma were retrospectively evaluated. Dimensionality reduction was undertaken by selecting metabolite concentrations through multi-class receiver operating characteristics and compared with principal component analysis. Classification accuracy was determined through leave-one-out and k-fold cross-validation. Metabolites identified as crucial in tumour classification include myo-inositol (P < 0.05, AUC = 0 . 81 ± 0 . 01 ), total lipids and macromolecules at 0.9 ppm (P < 0.05, AUC = 0 . 78 ± 0 . 01 ) and total creatine (P < 0.05, AUC = 0 . 77 ± 0 . 01 ) for the 1.5 T cohort, and glycine (P < 0.05, AUC = 0 . 79 ± 0 . 01 ), total N-acetylaspartate (P < 0.05, AUC = 0 . 79 ± 0 . 01 ) and total choline (P < 0.05, AUC = 0 . 75 ± 0 . 01 ) for the 3 T cohort. Compared with the principal components, the selected metabolites were able to provide significantly improved discrimination between the tumours through most classifiers (P < 0.05). The highest balanced classification accuracy determined through leave-one-out cross-validation was 85% for 1.5 T 1 H-MRS through support vector machine and 75% for 3 T 1 H-MRS through linear discriminant analysis after oversampling the minority. The study suggests that a group of crucial metabolites helps to achieve better discrimination between childhood brain tumours., (© 2022 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd.)

1 H-magnetic resonance spectroscopy (MRS) provides noninvasive metabolite profiles with the potential to aid the diagnosis of brain tumours. Prospective studies of diagnostic accuracy and comparisons with conventional MRI are lacking. The aim of the current study was to evaluate, prospectively, the diagnostic accuracy of a previously established classifier for diagnosing the three major childhood cerebellar tumours, and to determine added value compared with standard reporting of conventional imaging. Single-voxel MRS (1.5 T, PRESS, TE 30 ms, TR 1500 ms, spectral resolution 1 Hz/point) was acquired prospectively on 39 consecutive cerebellar tumours with histopathological diagnoses of pilocytic astrocytoma, ependymoma or medulloblastoma. Spectra were analysed with LCModel and predefined quality control criteria were applied, leaving 33 cases in the analysis. The MRS diagnostic classifier was applied to this dataset. A retrospective analysis was subsequently undertaken by three radiologists, blind to histopathological diagnosis, to determine the change in diagnostic certainty when sequentially viewing conventional imaging, MRS and a decision support tool, based on the classifier. The overall classifier accuracy, evaluated prospectively, was 91%. Incorrectly classified cases, two anaplastic ependymomas, and a rare histological variant of medulloblastoma, were not well represented in the original training set. On retrospective review of conventional MRI, MRS and the classifier result, all radiologists showed a significant increase (Wilcoxon signed rank test, p < 0.001) in their certainty of the correct diagnosis, between viewing the conventional imaging and MRS with the decision support system. It was concluded that MRS can aid the noninvasive diagnosis of posterior fossa tumours in children, and that a decision support classifier helps in MRS interpretation., (© 2021 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd.)

Background: In neonatal encephalopathy, the clinical manifestations of injury can only be reliably assessed several years after an intervention, complicating early prognostication and rendering trials of promising neuroprotectants slow and expensive. We aimed to determine the accuracy of thalamic proton magnetic resonance (MR) spectroscopy (MRS) biomarkers as early predictors of the neurodevelopmental abnormalities observed years after neonatal encephalopathy., Methods: We did a prospective multicentre cohort study across eight neonatal intensive care units in the UK and USA, recruiting term and near-term neonates who received therapeutic hypothermia for neonatal encephalopathy. We excluded infants with life-threatening congenital malformations, syndromic disorders, neurometabolic diseases, or any alternative diagnoses for encephalopathy that were apparent within 6 h of birth. We obtained T 1 -weighted, T 2 -weighted, and diffusion-weighted MRI and thalamic proton MRS 4-14 days after birth. Clinical neurodevelopmental tests were done 18-24 months later. The primary outcome was the association between MR biomarkers and an adverse neurodevelopmental outcome, defined as death or moderate or severe disability, measured using a multivariable prognostic model. We used receiver operating characteristic (ROC) curves to examine the prognostic accuracy of the individual biomarkers. This trial is registered with ClinicalTrials.gov, number NCT01309711., Findings: Between Jan 29, 2013, and June 25, 2016, we recruited 223 infants who all underwent MRI and MRS at a median age of 7 days (IQR 5-10), with 190 (85%) followed up for neurological examination at a median age of 23 months (20-25). Of those followed up, 31 (16%) had moderate or severe disability, including one death. Multiple logistic regression analysis could not be done because thalamic N-acetylaspartate (NAA) concentration alone accurately predicted an adverse neurodevelopmental outcome (area under the curve [AUC] of 0·99 [95% CI 0·94-1·00]; sensitivity 100% [74-100]; specificity 97% [90-100]; n=82); the models would not converge when any additional variable was examined. The AUC (95% CI) of clinical examination at 6 h (n=190) and at discharge (n=167) were 0·72 (0·65-0·78) and 0·60 (0·53-0·68), respectively, and the AUC of abnormal amplitude integrated EEG at 6 h (n=169) was 0·73 (0·65-0·79). On conventional MRI (n=190), cortical injury had an AUC of 0·67 (0·60-0·73), basal ganglia or thalamic injury had an AUC of 0·81 (0·75-0·87), and abnormal signal in the posterior limb of internal capsule (PLIC) had an AUC of 0·82 (0·76-0·87). Fractional anisotropy of PLIC (n=65) had an AUC of 0·82 (0·76-0·87). MRS metabolite peak-area ratios (n=160) of NAA-creatine (<1·29) had an AUC of 0·79 (0·72-0·85), of NAA-choline had an AUC of 0·74 (0·66-0·80), and of lactate-NAA (>0·22) had an AUC of 0·94 (0·89-0·97)., Interpretation: Thalamic proton MRS measures acquired soon after birth in neonatal encephalopathy had the highest accuracy to predict neurdevelopment 2 years later. These methods could be applied to increase the power of neuroprotection trials while reducing their duration., Funding: National Institute for Health Research UK., (Copyright © 2019 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Purpose: 3T magnetic resonance scanners have boosted clinical application of 1 H-MR spectroscopy (MRS) by offering an improved signal-to-noise ratio and increased spectral resolution, thereby identifying more metabolites and extending the range of metabolic information. Spectroscopic data from clinical 1.5T MR scanners has been shown to discriminate between pediatric brain tumors by applying machine learning techniques to further aid diagnosis. The purpose of this multi-center study was to investigate the discriminative potential of metabolite profiles obtained from 3T scanners in classifying pediatric brain tumors., Methods: A total of 41 pediatric patients with brain tumors (17 medulloblastomas, 20 pilocytic astrocytomas, and 4 ependymomas) were scanned across four different hospitals. Raw spectroscopy data were processed using TARQUIN. Borderline synthetic minority oversampling technique was used to correct for the data skewness. Different classifiers were trained using linear discriminative analysis, support vector machine, and random forest techniques., Results: Support vector machine had the highest balanced accuracy for discriminating the three tumor types. The balanced accuracy achieved was higher than the balanced accuracy previously reported for similar multi-center dataset from 1.5T magnets with echo time 20 to 32 ms alone., Conclusion: This study showed that 3T MRS can detect key differences in metabolite profiles for the main types of childhood tumors. Magn Reson Med 79:2359-2366, 2018. © 2017 International Society for Magnetic Resonance in Medicine., (© 2017 International Society for Magnetic Resonance in Medicine.)

Introduction: Despite cooling, adverse outcomes are seen in up to half of the surviving infants after neonatal encephalopathy. A number of novel adjunct drug therapies with cooling have been shown to be highly neuroprotective in animal studies, and are currently awaiting clinical translation. Rigorous evaluation of these therapies in phase II trials using surrogate MR biomarkers may speed up their bench to bedside translation. A recent systematic review of single-centre studies has suggested that MR spectroscopy biomarkers offer the best promise; however, the prognostic accuracy of these biomarkers in cooled encephalopathic babies in a multicentre setting using different MR scan makers is not known., Methods and Analysis: The MR scanners (3 T; Philips, Siemens, GE) in all the participating sites will be harmonised using phantom experiments and healthy adult volunteers before the start of the study. We will then recruit 180 encephalopathic infants treated with whole body cooling from the participating centres. MRI and spectroscopy will be performed within 2 weeks of birth. Neurodevelopmental outcomes will be assessed at 18-24 months of age. Agreement between MR cerebral biomarkers and neurodevelopmental outcome will be reported. The sample size is calculated using the 'rule of 10', generally used to calculate the sample size requirements for developing prognostic models. Considering 9 parameters, we require 9×10 adverse events, which suggest that a total sample size of 180 is required., Ethics and Dissemination: Human Research Ethics Committee approvals have been received from Brent Research Ethics Committee (London), and from Imperial College London (Sponsor). We will submit the results of the study to relevant journals and offer national and international presentations., Trial Registration Number: Clinical Trials.gov Number: NCT01309711., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Among the high bone mass disorders, the osteopetroses reflect osteoclast failure that prevents skeletal resorption and turnover, leading to reduced bone growth and modeling and characteristic histopathological and radiographic findings. We report an 11-year-old boy with a new syndrome that radiographically mimics osteopetrosis (OPT), but features rapid skeletal turnover. He presented at age 21 months with a parasellar, osteoclast-rich giant cell granuloma. Radiographs showed a dense skull, generalized osteosclerosis and cortical thickening, medullary cavity narrowing, and diminished modeling of tubular bones. His serum alkaline phosphatase was >5000 IU/L (normal <850 IU/L). After partial resection, the granuloma re-grew but then regressed and stabilized during 3 years of uncomplicated pamidronate treatment. His hyperphosphatasemia transiently diminished, but all bone turnover markers, especially those of apposition, remained elevated. Two years after pamidronate therapy stopped, bone mineral density (BMD) Z-scores reached +9.1 and +5.8 in the lumbar spine and hip, respectively, and iliac crest histopathology confirmed rapid bone remodeling. Serum multiplex biomarker profiling was striking for low sclerostin. Mutation analysis was negative for activation of lipoprotein receptor-related protein 4 (LRP4), LRP5, or TGFβ1, and for defective sclerostin (SOST), osteoprotegerin (OPG), RANKL, RANK, SQSTM1, or sFRP1. Microarray showed no notable copy number variation. Studies of his nonconsanguineous parents were unremarkable. The etiology and pathogenesis of this unique syndrome are unknown., (© 2014 American Society for Bone and Mineral Research.)

Background: Open surgical biopsy is traditionally advocated prior to initiating therapy in UKCCLG neuroblastoma protocols. We report a single centre experience comparing the utility of open biopsy vs image guided needle biopsy in aiding the definitive diagnosis and risk stratification of neuroblastoma - (Shimada classification, MYCN expression, cytogenetics - 1p 11q, 17 q)., Methods: Medical records of all new cases of neuroblastoma presenting to a single UKCCLG centre during January 2002-July 2013 were examined., Results: Thirty nine patients underwent a biopsy of primary tumour for neuroblastoma during the study. Twenty one children had open biopsy and eighteen cases had a needle biopsy. Staging of neuroblastoma revealed - stage 4 (n=26), stage 3 (n=7), stage 2 (n=3) and stage 4S (n=3). Sites of primary tumour were adrenal gland (n=20), abdomen (n=12), thoracic (n=4), abdomino-thoracic (n=2) and abdomino pelvic regions (n=1). All patients (open vs needle) had adequate tissue retrieved for histological diagnosis of neuroblastoma. One needle and one open biopsy case did not have MYCN status determined despite adequate tissue sampling. Seventeen patients (7 open and 10 needle biopsies) had 1p and 17q status reported in MLPA testing (Multiplex Ligation-dependent Probe Amplification). No single patient required a repeat tumour biopsy. Morbidity in the series was minimal with only one child - open biopsy group, requiring emergent laparotomy to control bleeding from an abdominal primary tumour. No complications were recorded with needle biopsy., Conclusions: Open and image guided needle biopsy appear to yield adequate tissue sampling for diagnosis, risk classification and staging of neuroblastoma. Further larger co-operative studies may usefully guide national and international protocols., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background: In order to assess relationships between thyroid hormone status and findings on brain MRI, a subset of babies was recruited to a multi-centre randomised, placebo-controlled trial of levothyroxine (LT4) supplementation for babies born before 28 weeks' gestation (known as the TIPIT study, for Thyroxine supplementation In Preterm InfanTs). These infants were imaged at term-equivalence., Materials and Methods: Forty-five TIPIT participants had brain MRI using diffusion tensor imaging (DTI) to estimate white matter development by apparent diffusion coefficient (ADC), fractional anisotropy (FA) and tractography metrics of number and length of streamlines. We made comparisons between babies with the lowest and highest plasma FT4 concentrations during the initial 4 weeks after birth., Results: There were no differences in DTI metrics between babies who had received LT4 supplementation and those who had received a placebo. Among recipients of a placebo, babies in the lowest quartile of plasma-free thyroxine (FT4) concentrations had significantly higher apparent diffusion coefficient measurements in the posterior corpus callosum and streamlines that were shorter and less numerous in the right internal capsule. Among LT4-supplemented babies, those who had plasma FT4 concentrations in the highest quartile had significantly lower apparent diffusion coefficient values in the left occipital lobe, higher fractional anisotropy in the anterior corpus callosum and longer and more numerous streamlines in the anterior corpus callosum., Conclusion: DTI variables were not associated with allocation of placebo or thyroid supplementation. Markers of poorly organised brain microstructure were associated with low plasma FT4 concentrations after birth. The findings suggest that plasma FT4 concentrations affect brain development in very immature infants and that the effect of LT4 supplementation for immature babies with low FT4 plasma concentrations warrants further study.

MRI is the ideal modality for imaging intracranial tumours. Intraoperative MRI (ioMRI) makes it possible to obtain scans during a neurosurgical operation that can aid complete macroscopic tumour resection—a major prognostic factor in the majority of brain tumours in children. Intraoperative MRI can also help limit damage to normal brain tissue. It therefore has the potential to improve the survival of children with brain tumours and to minimise morbidity, including neurological deficits. The use of ioMRI is also likely to reduce the need for second look surgery, and may reduce the need for chemotherapy and radiotherapy. Highfield MRI systems provide better anatomical information and also enable effective utilisation of advanced MRI techniques such as perfusion imaging, diffusion tensor imaging, and magnetic resonance spectroscopy. However, high-field ioMRI facilities require substantial capital investment, and careful planning is required for optimal benefit. Safe ioMRI requires meticulous attention to detail and rigorous application of magnetic field safety precautions. Interpretation of ioMRI can be challenging and requires experience and understanding of artefacts that are common in the intra-operative setting.

Background: Intraoperative MRI (ioMRI) has been gaining recognition because of its value in the neurosurgical management of cranial tumours. There is limited documentation of its value in children., Objectives: To review the initial experience of a paediatric 3-Tesla ioMRI unit in the management of cranial tumours., Materials and Methods: Thirty-eight children underwent ioMRI during 40 cranial tumour resections using a 3-Tesla MR scanner co-located with the neurosurgical operating theatre. IoMRI was performed to assess the extent of tumour resection and/or to update neuronavigation. The intraoperative and follow-up scans, and the clinical records were reviewed., Results: In 27/40 operations, complete resection was intended. IoMRI confirmed complete resection in 15/27 (56%). As a consequence, surgical resection was extended in 5/27 (19%). In 6/27 (22%), ioMRI was equivocal for residual tumour. In 13/40 (33%) operations, the surgical aim was to partially resect the tumour. In 7 of the 13 (54%), surgical resection was extended following ioMRI., Conclusion: In our initial experience, ioMRI has increased the rate of complete resection, with intraoperative surgical strategy being modified in 30% of procedures. Collaborative analysis of ioMRI by the radiologist and neurosurgeon is vital to avoid errors in interpretation.

Background: High-field intraoperative MRI (IoMRI) is gaining increasing recognition as an invaluable tool in pediatric brain tumor surgery where the extent of tumor resection is a major prognostic factor. We report the initial experience of a dedicated pediatric 3-T intraoperative MRI (IoMRI) unit with integrated neuronavigation in the management of pediatric brain tumors., Methods: Seventy-three children (mean age 9.5 years; range 0.2-19 years) underwent IoMRI between October 2009 and January 2012, during 79 brain tumor resections using a 3-T MR scanner located adjacent to the neurosurgical operating theater that is equipped with neuronavigation facility. IoMRI was performed either to assess the extent of tumor resection after surgical impression of complete/intended tumor resection or to update neuronavigation. The surgical aims, IoMRI findings, extent of tumor resection, and follow-up data were reviewed., Results: Complete resection was intended in 47/79 (59%) operations. IoMRI confirmed complete resection in 27/47 (57%). IoMRI findings led to further resection in 12/47 (26%). In 7/47 (15%), IoMRI was equivocal for residual tumor and no evidence of residual tumor was found on re-inspection. In 32/79 (41%) operations, the surgical aim was partial tumor resection. In this subset, surgical resection was extended following IoMRI in 13/32 (41%) operations. None of the patients required early second look procedure for residual disease., Conclusions: At our institution, IoMRI has led to increased rate of tumor resection and a change in surgical strategy with further tumor resection in 32% of patients. While interpreting IoMRI, it is important to be aware of the known pitfalls.

A 12-year-old girl with protracted tuberculous meningitis received standard chemotherapy and dexamethasone and had a progressive cerebrospinal fluid neutrophilia, raised protein and depressed glucose levels. Her temperature was raised for 5 months until a second course of dexamethasone was given. At week 15, multiple tuberculomas and hydrocephalus were detected followed by acute hydrocephalus (week 58), which required a ventricular-peritoneal shunt. Tuberculomas resolved after a second course of dexamethasone but recurred 15 months later. Immunological investigations were normal including integrity of the type 1 cytokine pathway. From month 24, interferon-gamma was given subcutaneously (initially 50 microg/m(2)) and continued for 19 months. Within 2 weeks she responded clinically followed by a reduction in inflammatory signs on magnetic resonance imaging scan (but not in the tuberculomas). At month 44, when chemotherapy was stopped, the cerebrospinal fluid/serum albumin quotient was 57x10(-3) (normal <6.0x10(-3)), which supports continuing major impairment of the blood-brain barrier. Gene expression in peripheral blood mononuclear cells before and during treatment with interferon-gamma, assessed by gene array analysis, showed reduction in a number of cytokine and chemokine genes. The response to interferon-gamma might have been secondary to downregulation of certain cytokine and chemokine genes.

Guanidinoacetate methyltransferase (GAMT) deficiency is a rare disorder of creatine synthesis. We report a patient who presented at 10 months of age with hypotonia and global developmental delay. Subsequently, she developed seizures and choreoathetosis. Magnetic resonance imaging showed high signal bilaterally in the globus pallidus on T2-weighted images. Mitochondrial respiratory chain studies revealed low complex I activity (in muscle 0.052 nmol NADH oxidized per min per unit citrate synthase, controls 0.166 +/- 0.047; in fibroblasts 0.080 nmol NADH oxidized per min per unit citrate synthase, controls 0.197 +/- 0.034). The true diagnosis was suspected at 21 months of age because of persistent low plasma and urine creatinine concentrations. GAMT activity was undetectable in fibroblasts and compound heterozygous mutations were found in the GAMT gene (c.327G>A and c.522G>A). The patient was treated with creatine, dietary arginine restriction and ornithine supplements. Her movement disorder and seizures resolved but she still has severe cognitive impairment and no expressive language. The occurrence of secondary respiratory chain abnormalities in GAMT deficiency may lead to misdiagnosis, particularly as the clinical and radiological features resemble those seen in mitochondrial encephalopathies. It is important to establish the correct diagnosis because specific treatment is available.

Children who survive very preterm birth without major disability have a high prevalence of learning difficulty, attention deficit, and minor motor impairment (MMI). To determine whether these difficulties are associated with structural brain abnormalities, we studied 105 preterm children (<32 wk) at 7 y with tests of IQ and MMI (Movement ABC) and detailed magnetic resonance brain scans. Scans were assessed qualitatively for visible cerebral lesions. Volume measurements of the caudate nuclei and hippocampal formations were made. Total brain volume (TBV) was estimated from the head circumference. Qualitative assessment of the scans showed evidence of cerebral lesions in 20 (19%), which were associated with lower IQ and more frequent MMI. IQ correlated with right and left caudate volume (Spearman's rho 0.304 and 0.349; p < 0.01). This association persisted (except for verbal IQ) when caudate volume was expressed as a percentage of estimated TBV to allow for overall brain size. No significant correlations with hippocampal volumes were observed. These differences persisted when only scans from children without visible lesions on scan were considered. MMI was significantly associated only with TBV and was more common in children with evidence of thinning of the posterior corpus callosum, although most children with MMI have a normal corpus callosum. Lower IQs in children who were born preterm are related to poorer development of the caudate relative to the rest of the brain, independent of other lesions. These findings suggest abnormal brain development after perinatal injury or postnatal nutritional deficits is responsible for cognitive deficits in preterm children.

We report a 9-month-old boy who presented with a hard paratesticular mass. Clinical and ultrasound findings were highly suggestive of malignancy and orchidectomy was performed. Histology confirmed the unexpected diagnosis of meconium periorchitis, a rare, benign condition resulting from intrauterine bowel perforation.

The objective of this study was to determine whether intelligence and minor motor impairments in children who are born preterm without major disability are associated with cerebral white matter (CWM) and hippocampal abnormalities on magnetic resonance imaging (MRI). A total of 103 preterm children were studied at age 7 y with detailed magnetic resonance brain scans, including a T2-mapping sequence from which T2 relaxation times of the CWM and hippocampal formations were calculated. All of the children had no major motor disability, attended normal school, and had undergone assessment of IQ and a test for minor motor impairment (MMI). Twenty children had visible lesions on MRI, which were associated with lower IQ and more frequent MMI. Mean (SD) IQ was 90 (14.1). Twenty-five children were shown to have MMI (Movement ABC at below the fifth centile). This group was shown to have significantly longer T2 relaxation times for CWM (mean difference 2.1 ms right, 3.1 ms left) but not the hippocampus than the children without MMI. These differences persisted when only children without visible lesions on scans were considered (mean difference 1.5 ms bilaterally). There was no significant correlation between IQ and T2 relaxation times. Children who are born preterm without subsequent major neurodisability may, in addition to visible lesions on MRI scans, have a diffuse abnormality of CWM, manifest as an increase in T2 relaxation time. This abnormality shows a close correlation with minor motor impairment but not with full-scale IQ.

Accurate diagnosis and classification of haemangiomas and vascular malformations is essential for prediction of outcome and rational therapeutic intervention. The purpose of this review is to demonstrate how radiological techniques, including projectional radiography, ultrasound and colour flow imaging, magnetic resonance imaging, and conventional venography and arteriography can aid in the diagnosis and classification of vascular malformations in children, and to guide the radiologist in the use of modern nomenclature.

Objective: To review the 10 years' practice of retrograde embolisation of varicoceles in the paediatric age group., Patients and Methods: 40 boys (age range, 6-16 years), with varicocele diagnosed both clinically and sonographically, were referred to the radiology department for embolisation. Data of these patients were collected and analysed retrospectively. Patients' age, side, treatment, complications, and outcome were noted. The follow-up ranges from 2 months to 6 years (mean, 1.1 years)., Results: In 24 patients (60%), embolisation was successful at the first attempt and 11 procedures (27.5%) were technical failures; 4 patients (10%) after venography were considered non-embolisable. One patient (2.5%) is yet to be seen in the clinic. Recurrence occurred in 4 patients (10%) of whom 3 had successful repeat embolisation. One patient with a recurrent varicocele did not wish further treatment. Out of the 11 failures, 5 underwent repeat embolisation with success in 3 patients and failure in two. Four patients had successful surgical ligation and 2 patients were treated conservatively. All who were non-embolisable were treated successfully by surgery. Our overall success rate was 65% (n = 26)., Conclusions: These results suggest that embolisation is valuable as a first line of treatment for paediatric varicoceles provided a skilled interventional radiologist is available. This procedure is less invasive, avoids general anaesthetic, involves minimal postoperative pain, and allows an earlier return to normal activities. However, 35% of patients did eventually require conventional surgery for primary failure of embolisation or late recurrence.

Background: Children who survive very low birth weight (VLBW) without major disability have a high prevalence of learning difficulty, attention deficit, and dyspraxia., Aims: To determine whether learning difficulty in children with VLBW is associated with structural brain abnormalities., Methods: A total of 87 children (aged 15-16 years) with a history of VLBW (<1500 g) and eight age matched full term controls have been studied with detailed magnetic resonance brain scans. Volume measurements of the caudate nuclei and hippocampal formations were made., Results: Scans in 42.5% of the children showed evidence of perinatal brain injury. There was no significant difference in IQ, dyspraxia, or attention deficit between children with qualitatively normal and abnormal scans. However, quantitative volumetric analysis showed that children with a low IQ had smaller volume measurements for the right caudate nucleus and left hippocampus, and a smaller hippocampal ratio (left volume:right volume) than those with normal IQ., Conclusion: Data suggest that learning disorder, attention deficit, and dyspraxia in children who survive VLBW do not correlate with conventional markers of perinatal brain injury, and may be related to global brain growth and the development of key structures, such as the caudate nuclei and hippocampal formations.

Background/purpose: Venous thrombosis is a well-recognised complication of central venous catheters (CVC). The aim of the study was to assess the value of magnetic resonance venography (MRV) in assessing venous patency in children with suspected venous thrombosis., Methods: Contrast studies through the CVC (linogram) and Doppler ultrasonography were the initial investigations performed in children with suspected CVC-related thrombosis. Two-dimensional gated inflow and phase contrast MRV also was performed to assess the extent of venous thrombosis and to locate patent veins for replacement CVC. When the MRV identified a suitable patent vein, the CVC was reinserted by direct venous cut down or the percutaneous method under a general anaesthetic., Results: A total of 25 children (median age, 5 years; range, 2 months to 17 years) who had multiple CVC insertions (median, 3; range, 1-9), underwent MRV for suspected venous thrombosis. Of 10 patients in whom the catheter was completely occluded, MRV identified extensive thrombosis of the central veins in 6. In 7 other children the linogram showed adherent thrombus at the tip of the CVC only. In 5 of these 7 children MRV showed extensive thrombosis of the vein in which the catheters were placed. Doppler ultrasonography diagnosed thrombotic occlusion of the neck veins in 7 children. The MRV studies showed more extensive thrombosis in 4 of these 7 patients. Additionally, MRV showed thrombosis of the intrathoracic veins in 11 patients who had patent neck veins on ultrasound scan. MRV identified a patent vein for reinsertion of CVC in 22 of 25 children. At operation, venous patency was confirmed in 20 patients (91%)., Conclusion: MRV in children with suspected CVC-related thrombosis is more accurate than Doppler ultrasonography, and contrast studies for defining the extent of venous thrombosis. MRV correctly shows venous anatomy and patency for reinsertion of CVC.

We present a case of pineal teratoma in a symptomatically stable 6-year-old child in which MRI revealed intraventricular lipid accumulation in the absence of any primary tumour growth, metastatic disease or tumour degeneration.

Although orbital cellulitis is the most common cause of acute-onset proptosis with inflammatory signs in a child, the clinician should always be alert to the possibility of rhabdomyosarcoma. We describe an unusual presentation of acute-onset nonaxial proptosis of the left orbit without sinus disease or systemic toxicity in a 6-year-old boy. Our clinical differential diagnosis included orbital cellulitis, metastatic disease, capillary haemangioma, lymphangioma with cyst, ruptured dermoid cyst, and orbital rhabdomyosarcoma. Only after orbital biopsy and subsequent microbiologic confirmation were obtained was a diagnosis of chronic orbital abscess tenable. Features in our patient included paucity of symptoms and signs of inflammation. This case illustrates the difficulty in differentiating a chronic orbital infection from orbital rhabdomyosarcoma on the basis of clinical, laboratory, and orbital imaging findings. Possible causes of this unusual presentation are discussed.

Aim: To determine whether neurological deficits are associated with structural anomalies of the brain in very low birthweight (VLBW) infants with subsequent learning disorders but without cerebral palsy, or whether other factors, such as poor early growth, are responsible., Methods: Eighty seven VLBW infants and eight term controls who had been examined at school between the ages of 12 and 13 years, had cranial magnetic resonance imaging (MRI) scans at 15-17 years of age., Results: Thirty seven (42.5%) of the VLBW children had abnormalities reported on their scans (two porencephaly, 28 periventricular leucomalacia, 24 ventricular dilatation, and 15 thinning of the corpus callosum). No significant differences in intelligence quotient, motor clumsiness, or frequency of attention deficit / hyperactivity disorder were observed between those children with MRI lesions and those with normal scans. Quantitative measurements showed the VLBW infants had smaller brains, and a relatively smaller corpus callosum compared with controls. No association between brain measurements and school performance was observed among the VLBW infants., Conclusions: The difficulties experienced by VLBW children at school are unlikely to be the result of perinatal brain injury, but they might to be attributable to the effects of poor postnatal growth.

Background: Intra-abdominal abscess remains a significant cause of morbidity following appendicectomy. In children, little emphasis has been placed on the non-invasive management of this complication using antibiotic therapy alone. This study reviews the experience of a paediatric surgical department in managing abscess arising after appendicectomy., Methods: Hospital records of all children undergoing appendicectomy between January 1992 and January 1997 were reviewed retrospectively., Results: Some 1024 children underwent appendicectomy over a 5-year period. Twenty three patients (2.2 per cent) developed abscesses after appendicectomy. Non-operative management with intravenous or oral antibiotics alone was successful in 21 patients, with complete clinical and radiological resolution of the abscess. Drainage of the septic collection was performed in only two patients: by laparotomy (n=1) and by the transrectal route (n=1)., Conclusion: Antibiotic therapy alone is an efficacious and safe first-line treatment modality in children who develop this complication. Drainage of an abscess developing after appendicectomy is rarely necessary in children.

Objective: To investigate the use of a calcium infusion test in the diagnosis and localisation of insulin secreting tumours in children., Patients: Three patients with persistent hypoglycaemia of infancy (PHHI)., Procedure: During planned selective coeliac and mesenteric arteriography, serial samples were taken from a catheter in the right hepatic vein for insulin measurement following the injection of calcium gluconate., Results: In all three children, selective intra-arterial calcium stimulation produced a significant rise in plasma insulin and was of value in localising the pancreatic abnormality in one child. In vitro studies on islets of Langerhans isolated from this patient following partial pancreatectomy showed unresponsive intracellular calcium signalling of the cells when stimulated with high extracellular concentrations of glucose and potassium or with sulphonylurea drugs (tolbutamide), but normal responsiveness to increasing extracellular calcium concentrations., Conclusions: The findings suggest a functional abnormality of the calcium channel in PHHI and provide a rationale for the reported efficacy of channel blocking drugs in this condition. The role of selective intra-arterial calcium stimulation in the diagnosis of hyperinsulinaemic hypoglycaemia in childhood warrants further investigation.

Magnetic resonance imaging reveals the anatomy of the pituitary and hypothalamus with unique detail. The clinical and biochemical investigation of short stature in childhood may be difficult and complex; magnetic resonance imaging of the pituitary is a non-invasive technique which can help to clarify the diagnosis of growth hormone insufficiency and to determine its cause. Most cases of growth hormone insufficiency have previously been considered to be idiopathic; in about 60% of these children, magnetic resonance imaging shows a characteristic structural abnormality which has been termed pituitary stalk interruption syndrome. The most important role of magnetic resonance imaging is in the diagnosis of destructive lesions of the hypothalamic-pituitary axis which may initially present with growth failure.

Osteomyelitis in childhood is common and causes serious morbidity. X-rays and bone scans are the primary tools of radiological investigation. Other imaging techniques, including ultrasound, computed tomography, magnetic resonance imaging and white cell scintigraphy have a valuable role in difficult cases.

Magnetic resonance (MR) imaging of the pituitary in children with central diabetes insipidus usually shows absence of the normal high signal within the posterior gland. The high signal of the normal posterior pituitary is thought to be due to the presence of intra- cellular storage granules of vasopressin. MR imaging has been advocated as a useful investigation to aid in the distinction between central diabetes insipidus and other causes of thirst and polydipsia. We report the case of an infant with central diabetes insipidus in association with septo-optic dysplasia in whom MR imaging showed normal appearances of the posterior pituitary. The mechanism of central diabetes insipidus in this case may be related to a failure of hypothalamic function affecting osmoreception, rather than to a deficiency of vasopressin. Normal MR appearances of the pituitary do not exclude central diabetes insipidus in infants with midline cerebral malformations.

Ultrasonography was undertaken in nine children with late presenting acute osteomyelitis, in four children with typical superficial cellulitis, and in four with a soft tissue abscess. Ultrasound distinguished between superficial cellulitis, soft tissue abscess, and subperiosteal abscess. The abscesses were confirmed at operation, and a subperiosteal abscess was also detected in the child with deep periosseous cellulitis. Ultrasonography was particularly useful in confirming the existence of a subperiosteal abscess and in localizing it precisely in children with diffuse swelling and tenderness of a limb owing to late-acute osteomyelitis. Surgical drainage of pus can be avoided in patients without ultrasound features of an abscess and can be better planned in those who require it.

Caudate nucleus atrophy occurs in Huntington's disease and methods of measuring this have been described using axial CT, but these are indirect and lack sensitivity. We measured caudate nucleus area (blind to the subjects' clinical state) in 30 subjects with or at risk of Huntington's disease, and in 100 normal age matched controls. Fifteen subjects with established symptomatic Huntington's disease, 3 with early symptoms, and 3 presymptomatic subjects (2 showing a high probability for the Huntington's disease gene on genetic testing, and one who has since developed symptoms) were correctly identified. Three normal (gene negative) family members were also correctly identified. Outcome is awaited in 6. CT caudate area measurement is simple and reproducible and we have found it to be a useful confirmatory test for Huntington's disease.

Tongue position was assessed in 15 female patients at induction of anaesthesia with either thiopentone or propofol. A video recording of a midline sagittal section of the tongue was made using an ultrasound transducer placed below the chin, and representative figures analysed by an observer who was not aware of the patient's state. In 11 satisfactory recordings, the tongue movement was inconsistent in direction and not more than 8 mm in the anterior tongue and 6 mm in the posterior tongue. The movements detected did not suggest that the tongue is likely to be an important cause of airway obstruction on induction of anaesthesia.

We describe the case of a fourteen-year old girl with hypertension, in whom renal arterial stenosis was identified by Doppler ultrasound examination, with subsequent demonstration of typical features of fibromuscular dysplasia by selective renal arteriography. Percutaneous transluminal balloon angioplasty was performed, and a sustained improvement in renal arterial flow was confirmed by follow-up Doppler ultrasound examinations.

The case of a 64-year-old man who presented with unilateral pulsatile exophthalmos is described. A defect in the supero-medial wall of the orbit and an extraconal low density mass were demonstrated by orbital radiographs and CT. Positive contrast CT cisternography confirmed the diagnosis of a leptomeningeal cyst.