Philippe Clapuyt

Pediatric diffusion tensor imaging: Normal database and observation of the white matter maturation in early childhood

Recent advances in diffusion tensor imaging (DTI) have made it possible to reveal white matter anatomy and to detect neurological abnormalities in children. However, the clinical use of this technique is hampered by the lack of a normal standard of reference. The goal of this study was to initiate the establishment of a database of DTI images in children, which can be used as a normal standard of reference for diagnosis of pediatric neurological abnormalities. Seven pediatric volunteers and 23 pediatric patients (age range: 0-54 months) referred for clinical MR examinations, but whose brains were shown to be normal, underwent anatomical and DTI acquisitions on a 1.5 T MR scanner. The white matter maturation, as observed on DTI color maps, was described and illustrated. Changes in diffusion fractional anisotropy (FA), average apparent diffusion constant (ADC(ave)), and T2-weighted (T2W) signal intensity were quantified in 12 locations to characterize the anatomical variability of the maturation process. Almost all prominent white matter tracts could be identified from birth, although their anisotropy was often low. The evolution of FA, shape, and size of the white matter tracts comprised generally three phases: rapid changes during the first 12 months; slow modifications during the second year; and relative stability after 24 months. The time courses of FA, ADC(ave), and T2W signal intensity confirmed our visual observations that maturation of the white matter and the normality of its architecture can be assessed with DTI in young children. The database is available online and is expected to foster the use of this promising technique in the diagnosis of pediatric pathologies.

Parkes Weber syndrome, vein of Galen aneurysmal malformation, and other fast‐flow vascular anomalies are caused by RASA1 mutations

Capillary malformation‐arteriovenous malformation (CM‐AVM) is a newly recognized autosomal dominant disorder, caused by mutations in the RASA1 gene in six families. Here we report 42 novel RASA1 mutations and the associated phenotype in 44 families. The penetrance and de novo occurrence were high. All affected individuals presented multifocal capillary malformations (CMs), which represent the hallmark of the disorder. Importantly, one‐third had fast‐flow vascular lesions. Among them, we observed severe intracranial AVMs, including vein of Galen aneurysmal malformation, which were symptomatic at birth or during infancy, extracranial AVM of the face and extremities, and Parkes Weber syndrome (PKWS), previously considered sporadic and nongenetic. These fast‐flow lesions can be differed from the other two genetic AVMs seen in hereditary hemorrhagic telangiectasia (HHT) and in phosphatase and tensin homolog (PTEN) hamartomatous tumor syndrome. Finally, some CM‐AVM patients had neural tumors reminiscent of neurofibromatosis type 1 or 2. This is the first extensive study on the phenotypes associated with RASA1 mutations, and unravels their wide heterogeneity. Hum Mutat 29(7), 959–965, 2008.

2005 PRETEXT: a revised staging system for primary malignant liver tumours of childhood developed by the SIOPEL group

Over the last 15xa0years, various oncology groups throughout the world have used the PRETEXT system for staging malignant primary liver tumours of childhood. This paper, written by members of the radiology and surgery committees of the International Childhood Liver Tumor Strategy Group (SIOPEL), presents various clarifications and revisions to the original PRETEXT system.

RASA1 mutations and associated phenotypes in 68 families with capillary malformation-arteriovenous malformation

Capillary malformation–arteriovenous malformation (CM–AVM) is an autosomal‐dominant disorder, caused by heterozygous RASA1 mutations, and manifesting multifocal CMs and high risk for fast‐flow lesions. A limited number of patients have been reported, raising the question of the phenotypic borders. We identified new patients with a clinical diagnosis of CM–AVM, and patients with overlapping phenotypes. RASA1 was screened in 261 index patients with: CM–AVM (n = 100), common CM(s) (port‐wine stain; n = 100), Sturge–Weber syndrome (n = 37), or isolated AVM(s) (n = 24). Fifty‐eight distinct RASA1 mutations (43 novel) were identified in 68 index patients with CM–AVM and none in patients with other phenotypes. A novel clinical feature was identified: cutaneous zones of numerous small white pale halos with a central red spot. An additional question addressed in this study was the “second‐hit” hypothesis as a pathophysiological mechanism for CM–AVM. One tissue from a patient with a germline RASA1 mutation was available. The analysis of the tissue showed loss of the wild‐type RASA1 allele. In conclusion, mutations in RASA1 underscore the specific CM–AVM phenotype and the clinical diagnosis is based on identifying the characteristic CMs. The high incidence of fast‐flow lesions warrants careful clinical and radiologic examination, and regular follow‐up.

Treatment of extrahepatic portal hypertension in children by mesenteric-to-left portal vein bypass: a new physiological procedure

OBJECTIVEnTo achieve hepatic portal revascularisation and decompression of extrahepatic portal hypertension in children with cavernoma and obstruction caused by idiopathic portal vein thrombosis.nnnDESIGNnSelected cases.nnnSETTINGnTeaching hospitals. Belgium and Italy.nnnSUBJECTSn11 children who weighed between 5.9 and 54 kg (2 emergencies) with symptomatic extrahepatic portal hypertension.nnnINTERVENTIONnInterposition of venous autograft between the superior mesenteric vein and the distal (umbilical) portion of the left portal vein.nnnMAIN OUTCOME MEASURESnImprovements in symptoms and endoscopic appearance after operation.nnnRESULTSn2 bypasses had to be redone because they stenosed; all 11 were patent at the time of writing (median follow-up 6 months, range 1-32 months).nnnCONCLUSIONnThe bypass effectively relieved symptoms of extrahepatic portal hypertension by restoring normal hepatic portal blood flow.

Early occurrence of hepatocellular carcinoma in biliary atresia treated by liver transplantation

Abstract:u2002 A case of liver transplantation for HCC complicating BA in an eight‐month old infant is reported. HCC in BA is extremely rare. Screening of AFP and ultrasonographic examination should be performed regularly in patients with secondary biliary cirrhosis for early detection of HCC.

Sonographic assessment of the retroperitoneal position of the third portion of the duodenum: an indicator of normal intestinal rotation.

BackgroundThe diagnosis of intestinal malrotation is based on an upper gastrointestinal contrast series (UGI), which is considered the imaging reference standard. It may however be challenging even for experienced paediatric radiologists.ObjectiveThe purpose of this study was to demonstrate the agreement between UGI and US in assessing the position of the third portion of the duodenum (D3) and to show that a retroperitoneal duodenum indicates normal forgut rotation.Materials and methodsIn a prospective study, US assessment of the duodenum and the superior mesenteric vessels was performed in consecutive children who were referred for clinically indicated UGI at a single institution.ResultsEighty-five children, 5xa0months to 14xa0years old, were studied. In 82/85 (96%), both US and UGI suggested normal forgut rotation. In three children, US demonstrated a normal position of the D3 whereas UGI showed an abnormal position of the duodeno-jejunal junction.ConclusionUS is a non-invasive, easily performed technique for excluding malrotation. UGI may be reserved for situations where US does not demonstrate a normal position of the D3.

Risk factors and surgical management of anastomotic biliary complications after pediatric liver transplantation.

Biliary complications (BCs) still remain the Achilles heel of liver transplantation (LT) with an overall incidence of 10% to 35% in pediatric series. We hypothesized that (1) the use of alternative techniques (reduced size, split, and living donor grafts) in pediatric LT may contribute to an increased incidence of BCs, and (2) surgery as a first treatment option for anastomotic BCs could allow a definitive cure for the majority of these patients. Four hundred twenty‐nine primary pediatric LT procedures, including 88, 91, 47, and 203 whole, reduced size, split, and living donor grafts, respectively, that were performed between July 1993 and November 2010 were retrospectively reviewed. Demographic and surgical variables were analyzed, and their respective impact on BCs was studied with univariate and multivariate analyses. The modalities of BC management were also reviewed. The 1‐ and 5‐year patient survival rates were 94% and 90%, 89% and 85%, 94% and 89%, and 98% and 94% for whole, reduced size, split, and living donor liver grafts, respectively. The overall incidence of BCs was 23% (nu2009=u200998). Sixty were anastomotic complications [47 strictures (78%) and 13 fistulas (22%)]. The graft type was not found to be an independent risk factor for the development of BCs. According to a multivariate analysis, only hepatic artery thrombosis and acute rejection increased the risk of anastomotic BCs (Pu2009<u20090.001 and Pu2009=u20090.003, respectively). Anastomotic BCs were managed primarily with surgical repair in 59 of 60 cases with a primary patency rate of 80% (nu2009=u200947). These results suggest that (1) most of the BCs were anastomotic complications not influenced by the type of graft, and (2) the surgical management of anastomotic BCs may constitute the first and best therapeutic option. Liver Transpl 20:893‐903, 2014.

Parotid gland abnormality found in children seropositive for the human immunodeficiency virus (HIV)

Out of our series of 24 children seropositive for the Human Immunodeficiency Virus (HIV), parotid gland enlargement was noted in 4 children with AIDS-related complex (ARC) presenting also a Lymphocytic Interstitial Pneumonitis (LIP) on their chest radiographs. The ultrasound (US) aspect of the parotid gland suggests acinar enlargement (suggesting the presence of lymphocytic infiltration). The aspect displayed in the parotid mirrors the process developing in other areas (lungs, liver, spleen, lymphnodes), i.e. a syndrome of lymphocytic (CD8) proliferation present at the stage of ARC.

Percutaneous transjugular intrahepatic stent shunt for treatment of intractable varicose bleeding in paediatric patients.

Two 10-year and 11-year-old children with oesophageal and gastric varicose haemorrhage unresponsive to medical treatment and repeated endoscopic sclerotherapy underwent percutaneous transjugular intrahepatic portosystemic shunting (TIPSS). A newly developed introducing system was used. The procedure was performed to avoid the increased risk of emergency liver transplantation in children with hepatic failure. Immediately after the procedure bleeding stopped and the patients condition improved. Ascites disappeared and liver function improved. The stent shunt was shown to be patent by angiography and Doppler ultrasound for a follow up period of more than 1 year.ConclusionTIPSS may be of benefit in children with severe portal hypertension. It allows control of intractable bleeding, and stabilizes the patients preparing them for subsequent elective orthotopic liver transplantation.