Automatic quantification of the microvascular density on whole slide images, applied to paediatric brain tumours

Angiogenesis is a key phenomenon for tumour progression, diagnosis and treatment in brain tumours and more generally in oncology. Presently, its precise, direct quantitative assessment can only be done on whole tissue sections immunostained to reveal vascular endothelial cells. But this is a tremendous task for the pathologist and a challenge for the computer since digitised whole tissue sections, whole slide images (WSI), contain typically around ten gigapixels. We define and implement an algorithm that determines automatically, on a WSI at objective magnification $40\times$, the regions of tissue, the regions without blur and the regions of large puddles of red blood cells, and constructs the mask of blur-free, significant tissue on the WSI. Then it calibrates automatically the optical density ratios of the immunostaining of the vessel walls and of the counterstaining, performs a colour deconvolution inside the regions of blur-free tissue, and finds the vessel walls inside these regions by selecting, on the image resulting from the colour deconvolution, zones which satisfy a double-threshold criterion. A mask of vessel wall regions on the WSI is produced. The density of microvessels is finally computed as the fraction of the area of significant tissue which is occupied by vessel walls. We apply this algorithm to a set of 186 WSI of paediatric brain tumours from World Health Organisation grades I to IV. The segmentations are of very good quality although the set of slides is very heterogeneous. The computation time is of the order of a fraction of an hour for each WSI on a modest computer. The computed microvascular density is found to be robust and strongly correlates with the tumour grade. This method requires no training and can easily be applied to other tumour types and other stainings

Feature selection and classification of imbalanced datasets. Application to PET images of children with Autistic Spectrum Disorders

Learning with discriminative methods is generally based on minimizing themisclassification of training samples, which may be unsuitable for imbalanceddatasets where the recognition might be biased in favor of the most numerousclass. This problem can be addressed with a generative approach, which typicallyrequires more parameters to be determined leading to reduced performances inhigh dimension. In such situations, dimension reduction becomes a crucial issue.We propose a feature selection / classification algorithm based on generativemethods in order to predict the clinical status of a highly imbalanced datasetmade of PET scans of forty-five low-functioning children with autism spectrumdisorders (ASD) and thirteen non-ASD low-functioning children. ASDs aretypically characterized by impaired social interaction, narrow interests, andrepetitive behaviours, with a high variability in expression and severity. Thenumerous findings revealed by brain imaging studies suggest that ASD isassociated with a complex and distributed pattern of abnormalities that makesthe identification of a shared and common neuroimaging profile a difficult task.In this context, our goal is to identify the rest functional brain imagingabnormalities pattern associated with ASD and to validate its efficiency inindividual classification. The proposed feature selection algorithm detected acharacteristic pattern in the ASD group that included a hypoperfusion in theright Superior Temporal Sulcus (STS) and a hyperperfusion in the contralateralpostcentral area. Our algorithm allowed for a significantly accurate (88\%),sensitive (91\%) and specific (77\%) prediction of clinical category. For thisimbalanced dataset, with only 13 control scans, the proposed generativealgorithm outperformed other state-of-the-art discriminant methods. The highpredictive power of the characteristic pattern, which has been automaticallyidentified on whole brains without any priors, confirms previous findingsconcerning the role of STS in ASD. This work offers exciting possibilities forearly autism detection and/or the evaluation of treatment response in individualpatients

Nouveautés radiologiques dans le dépistage et le diagnostic des erreurs innées du métabolisme

Les maladies héréditaires du métabolisme ont acquis une place de plus en plus importante dans la pathologie pédiatrique. Leur nombre ne cesse d’augmenter au fur et à mesure de la progression des connaissances en biologie cellulaire et des progrès techniques d’investigation. Nous traiterons ici de trois maladies métaboliques que l’imagerie fonctionnelle et la spectroscopie IRM ont permis d’identifier. Il s’agit des déficits en créatine traitables par l’administration de créatine et les défauts du métabolisme des polyols qui ouvrent le champ sur de nouveaux déficits enzymatiques responsables de présentations cliniques très variées. Nous aborderons également les hyperinsulinismes du jeune enfant dont le diagnostic et la prise en charge ont été récemment transformées par l’utilisation de la [18F]-fluoro-L-DOPA en tomographie par émission de positons.New metabolic diseases are regularly identified by a genetic or biochemical approach. Indeed, the metabolic diseases result from an enzymatic block with accumulation of a metabolite upstream to the block and deficit of a metabolite downstream. The characterization of these abnormal metabolites by MRI spectroscopy permitted to identify the deficient enzyme in two new groups of diseases, creatine deficiencies and polyol anomalies. Creatine deficiency is implicated in unspecific mental retardation. A low peak of creatine at MRI spectroscopy is evocating of creatine deficiency which is treatable by creatine administration. Deficiency of synthesis of polyols, metabolites on the pentose pathway, represent new described metabolic diseases with variable symptoms including a neurological distress, liver disease, splenomegaly, cutis laxa and renal insufficiency. The deficit of ribose-5-phosphate isomerase, one of the enzymes whose diagnosis is evoked in front of the accumulation of ribitol, arabitol and xylitol leads to a leucodystrophy in adults. This new deficit was highlighted by the identification of an abnormal peak in cerebral MRI-spectroscopy corresponding to the abnormal accumulation of polyols in brain. Congenital hyperinsulinism (HI) is characterized by profound hypoglycaemia related to inappropriate insulin secretion. Focal and diffuse forms of hyperinsulinism share a similar clinical presentation but their treatment is dramatically different. Until recently, preoperative differential diagnosis was based on pancreatic venous sampling, an invasive and technically demanding technique. Positron emission tomography (PET) after injection of [18F]Fluoro-L-DOPA has been evaluated for the preoperative differentiation between focal and diffuse HI, by imaging uptake of radiotracer and the conversion of [18F]Fluoro-L-DOPA into dopamine by DOPA decarboxylase. PET with [18F]Fluoro-L-DOPA has been validated as a reliable test to differentiate diffuse and focal HI and is now a major differential diagnosis tool in infantile hyperinsulinemic hypoglycaemia

Long-term neurological outcome of a cohort of 80 patients with classical organic acidurias.

International audienceBACKGROUND: Classical organic acidurias including methylmalonic aciduria (MMA), propionic aciduria (PA) and isovaleric aciduria (IVA) are severe inborn errors of the catabolism of branched-chain amino acids and odd-numbered chain fatty acids, presenting with severe complications. METHODS: This study investigated the long-term outcome of 80 patients with classical organic aciduria (38 with MMA, 24 with PA and 18 with IVA) by integrating clinical, radiological, biochemical and genetic data. RESULTS: Patients were followed-up for a mean of 14 years [age 3.3-46.3 years]. PA included a greater number of patients with abnormal neurological examination (37% in PA, 24% in MMA and 0% in IVA), lower psychometric scores (abnormal evaluation at age 3 years in 61% of patients with PA versus 26% in MMA and 18% in IVA) and more frequent basal ganglia lesions (56% of patients versus 36% in MMA and 17% in IVA). All patients with IVA presented a normal neurological examination and only 1/3 presented cognitive troubles. Prognosis for MMA was intermediate. Biochemical metabolite analysis excluding acute decompensations revealed significant progressive increases of glycine, alanine and glutamine particularly in PA and possibly in MMA but no correlation with neurological outcome. A significant increase of plasma methylmalonic acid was found in MMA patients with intellectual deficiency (mean level of 199 mumol/L versus 70 mumol/L, p < 0.05), with an estimated significant probability of severe outcome for average levels between birth and age 6 years above 167 mumol/L. Urinary 3-hydroxypropionate (3-HP) levels were significantly higher in PA patients with intellectual deficiency (mean level of 68.9 mumol/mmol of creatinine versus 34.6 mumol/mmol of creatinine, p < 0.01), with an estimated significant probability of severe outcome for average levels between birth and age 6 years above 55 mumol/mmol. As for molecular analysis, prognosis of MMA patients with mutations involving the MMAA gene was better compared to patients with mutations involving the MUT gene. CONCLUSION: Propionic aciduria had the most severe neurological prognosis. Our radiological and biochemical data are consistent with a mitochondrial toxicity mechanism. Follow-up plasma MMA and urinary 3-HP levels may have prognostic significance calling for greater efforts to optimize long-term management in these patients

MRI Findings in 77 Children with Non-Syndromic Autistic Disorder

International audienceBACKGROUND: The clinical relevance of MR scanning in children with autism is still an open question and must be considered in light of the evolution of this technology. MRI was judged to be of insufficient value to be included in the standard clinical evaluation of autism according to the guidelines of the American Academy of Neurology and Child Neurology Society in 2000. However, this statement was based on results obtained from small samples of patients and, more importantly, included mostly insufficient MRI sequences. Our main objective was to evaluate the prevalence of brain abnormalities in a large group of children with a non-syndromic autistic disorder (AD) using T1, T2 and FLAIR MRI sequences. METHODOLOGY: MRI inspection of 77 children and adolescents with non-syndromic AD (mean age 7.4+/-3.6) was performed. All met the DSM-IV and ADI -R criteria for autism. Based on recommended clinical and biological screenings, we excluded patients with infectious, metabolic or genetic diseases, seizures or any other neurological symptoms. Identical MRI inspections of 77 children (mean age 7.0+/-4.2) without AD, developmental or neurological disorders were also performed. All MRIs were acquired with a 1.5-T Signa GE (3-D T1-FSPGR, T2, FLAIR coronal and axial sequences). Two neuroradiologists independently inspected cortical and sub-cortical regions. MRIs were reported to be normal, abnormal or uninterpretable. PRINCIPAL FINDINGS: MRIs were judged as uninterpretable in 10% (8/77) of the cases. In 48% of the children (33/69 patients), abnormalities were reported. Three predominant abnormalities were observed, including white matter signal abnormalities (19/69), major dilated Virchow-Robin spaces (12/69) and temporal lobe abnormalities (20/69). In all, 52% of the MRIs were interpreted as normal (36/69 patients). CONCLUSIONS: An unexpectedly high rate of MRI abnormalities was found in the first large series of clinical MRI investigations in non-syndromic autism. These results could contribute to further etiopathogenetic research into autism

Laser interstitial thermal therapy is effective and safe for the treatment of brain tumors in NF1 patients after cerebral revascularization for moyamoya angiopathy: a report on two cases

BackgroundThe co-occurrence of moyamoya vasculopathy and extra-optic pathway tumors is rare in neurofibromatosis type 1 (NF1), with only four cases described in the literature. Brain surgery in these patients may be challenging because of the risk of brain infarction after skin and dural incision. Given its percutaneous and minimally invasive nature, laser interstitial thermal therapy (LITT) is an ideal option for the treatment of brain tumors in these patients. Here, we report on two patients with NF1 and moyamoya syndrome (MMS) treated for a brain glioma with LITT, after cerebral revascularization.CasesThe first patient, with familial NF1, underwent bilateral indirect revascularization with multiple burr holes (MBH) for symptomatic MMS. Two years later, she was diagnosed with a left temporal tumor, with evidence of radiologic progression over 10 months. The second patient, also with familial NF1, developed unilateral MMS when he was 6 years old and was treated with MBH. At the age of 15 years, MRI showed a right cingular lesion, growing on serial MRIs. Both patients underwent LITT with no perioperative complications; they are progression free at 10 and 12 months, respectively, and the tumors have decreased in volume.DiscussionWhile the association of extra-optic neoplasm and moyamoya angiopathy is seldom reported in NF1, tumor treatment is challenging in terms of both avoiding stroke and achieving oncological control. Here, we show in 2 cases, that LITT could be a safe and effective option in these rare conditions

Utility of whole exome sequencing for the early diagnosis of pediatric-onset cerebellar atrophy associated with developmental delay in an inbred population

International audienceAbstractBackgroundCerebellar atrophy and developmental delay are commonly associated features in large numbers of genetic diseases that frequently also include epilepsy. These defects are highly heterogeneous on both the genetic and clinical levels. Patients with these signs also typically present with non-specific neuroimaging results that can help prioritize further investigation but don’t suggest a specific molecular diagnosis.MethodsTo genetically explore a cohort of 18 Egyptian families with undiagnosed cerebellar atrophy identified on MRI, we sequenced probands and some non-affected family members via high-coverage whole exome sequencing (WES; >97 % of the exome covered at least by 30x). Patients were mostly from consanguineous families, either sporadic or multiplex. We analyzed WES data and filtered variants according to dominant and recessive inheritance models.ResultsWe successfully identified disease-causing mutations in half of the families screened (9/18). These mutations are located in seven different genes, PLA2G6 being the gene most frequently mutated (n = 3). We also identified a recurrent de novo mutation in the KIF1A gene and a molybdenum cofactor deficiency caused by the loss of the start codon in the MOCS2A open-reading frame in a mildly affected subject.ConclusionsThis study illustrates the necessity of screening for dominant mutations in WES data from consanguineous families. Our identification of a patient with a mild and improving phenotype carrying a previously characterized severe loss of function mutation also broadens the clinical spectrum associated with molybdenum cofactor deficiency

Evidence of spinal stiffening following fusionless bipolar fixation for neuromuscular scoliosis: a shear wave elastography assessment of lumbar annulus fibrosus

Objectives There are no established criteria for stiffness after fusionless surgery for neuromuscular scoliosis (NMS). As a result, there is no consensus regarding the surgical strategy to propose at long-term follow-up. This study reports the first use of shear wave elastography for assessing the mechanical response of lumbar intervertebral discs (IVDs) after fusionless bipolar fixation (FBF) for NMS and compares them with healthy controls. The aim was to acquire evidence from the stiffness of the spine following FBF. Patients and methods Nineteen NMS operated on with FBF (18 ± 2y at last follow-up, 6 ± 1 y after surgery) were included prospectively. Preoperative Cobb was 89 ± 20° and 35 ± 1° at latest follow-up. All patients had reached skeletal maturity. Eighteen healthy patients (20 ± 4 y) were also included. Shear wave speed (SWS) was measured in the annulus fibrosus of L3L4, L4L5 and L5S1 IVDs and compared between the two groups. A measurement reliability was performed. Results In healthy subjects, average SWS (all disc levels pooled) was 7.5 ± 2.6 m/s. In NMS patients, SWS was significantly higher at 9.9 ± 1.4 m/s (p < 0.05). Differences were significant between L3L4 (9.3 ± 1.8 m/s vs. 7.0 ± 2.5 m/s, p = 0.004) and L4L5 (10.3 ± 2.3 m/s vs. 7.1 ± 1.1 m/s, p = 0.0006). No difference was observed for L5S1 (p = 0.2). No correlation was found with age at surgery, Cobb angle correction and age at the SWE measurement. Conclusions This study shows a significant increase in disc stiffness at the end of growth for NMS patients treated by FBF. These findings are a useful adjunct to CT-scan in assessing stiffness of the spine allowing the avoidance of surgical final fusion at skeletal maturity

GERMLINE GAIN-OF-FUNCTION MUTATIONS of ALK DISRUPT CENTRAL NERVOUS SYSTEM DEVELOPMENT

International audienceNeuroblastoma (NB) is a frequent embryonal tumour of sympathetic ganglia and adrenals with extremely variable outcome. Recently, somatic amplification and gain-of-function mutations of the anaplastic lymphoma receptor tyrosine kinase (ALK, MIM 105590) gene, either somatic or germline, were identified in a significant proportion of NB cases. Here we report a novel syndromic presentation associating congenital NB with severe encephalopathy and abnormal shape of the brainstem on brain MRI in two unrelated sporadic cases harbouring de novo, germline, heterozygous ALK gene mutations. Both mutations are gain-of-function mutations that have been reported in NB and NB cell lines. These observations further illustrate the role of oncogenes in both tumour predisposition and normal development, and shed light on the pleiotropic and activity-dependent role of ALK in humans. More generally, missing germline mutations relative to the spectrum of somatic mutations reported for a given oncogene may be a reflection of severe effects during embryonic development, and may prompt mutation screening in patients with extreme phenotypes

Epilepsy with migrating focal seizures

To report new sporadic cases and 1 family with epilepsy of infancy with migrating focal seizures (EIMFSs) due to KCNT1 gain-of-function and to assess therapies' efficacy including quinidine. We reviewed the clinical, EEG, and molecular data of 17 new patients with EIMFS and KCNT1 mutations, in collaboration with the network of the French reference center for rare epilepsies. The mean seizure onset age was 1 month (range: 1 hour to 4 months), and all children had focal motor seizures with autonomic signs and migrating ictal pattern on EEG. Three children also had infantile spasms and hypsarrhythmia. The identified KCNT1 variants clustered as "hot spots" on the C-terminal domain, and all mutations occurred de novo except the p.R398Q mutation inherited from the father with nocturnal frontal lobe epilepsy, present in 2 paternal uncles, one being asymptomatic and the other with single tonic-clonic seizure. In 1 patient with EIMFS, we identified the p.R1106Q mutation associated with Brugada syndrome and saw no abnormality in cardiac rhythm. Quinidine was well tolerated when administered to 2 and 4-year-old patients but did not reduce seizure frequency. The majority of the KCNT1 mutations appear to cluster in hot spots essential for the channel activity. A same mutation can be linked to a spectrum of conditions ranging from EMFSI to asymptomatic carrier, even in the same family. None of the antiepileptic therapies displayed clinical efficacy, including quinidine in 2 patients