Can diffusion weighting replace gadolinium enhancement in magnetic resonance enterography for inflammatory bowel disease in children?

BACKGROUND: Contrast-enhanced MRI is often used for diagnosis and follow-up of children with inflammatory bowel disease. OBJECTIVE: To compare the accuracy of diffusion-weighted MRI (DWI) to contrast-enhanced MRI in children with known or suspected inflammatory bowel disease. MATERIALS AND METHODS: This retrospective, consecutive study included 55 children. We used ileo-colonoscopy and histology as the reference standard from the terminal ileum to the rectum, and contrast-enhanced MRI as the reference standard proximal to the terminal ileum. DWI and contrast-enhanced MRI sequences were independently reviewed and compared per patient and per segment to these reference standards and to the follow-up for each child. RESULTS: We obtained endoscopic data for 340/385 colonic and ileal segments (88%). The rate of agreement per segment between DWI and endoscopy was 64%, and the rate of agreement between contrast-enhanced MRI and endoscopy was 59%. Per patient, sensitivity and specificity of bowel wall abnormalities as compared to the endoscopy were 87% and 100% for DWI, and 70% and 100% for contrast-enhanced MRI, respectively. Positive and negative predictive values were, respectively, 100% and 57% for DWI, and 96% and 41% for contrast-enhanced MRI. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of DWI compare to contrast-enhanced MRI in the segments proximal to the terminal ileum were 90%, 98%, 90%, 98% and 96%, respectively. CONCLUSION: The diagnostic performance of DWI is competitive to that of contrast-enhanced MRI in children with known or suspected inflammatory bowel disease.

A prospective pilot study: can the biliary tree be visualized in children younger than 3 months on Magnetic Resonance Cholangiopancreatography?

BACKGROUND: Magnetic resonance cholangiopancreatography (MRCP) could aid in the diagnosis of biliary atresia, a hepatic pathology with thin, irregular or interrupted biliary ducts. There is little published evidence of MRCP appearances in normal neonates and young infants. OBJECTIVE: To assess the use of MR cholangiopancreatography in visualizing the biliary tree in neonates and infants younger than 3 months with no hepatobiliary disorder, and to assess this visibility in relationship to the child's age, weight, and sedation and fasting states. MATERIALS AND METHODS: Between December 2008 and October 2010 our department performed MRI of the brain, orbits and face on 16 full-term neonates and infants. Each child was younger than 3 months (90 days) and without any hepatobiliary disorders. The children were scanned with a respiratory-gated 0.54 × 0.51 × 0.4-mm(3) 3-D MRCP sequence. We used a reading grid to assess subjectively the visibility of the extrahepatic bile ducts along with extrahepatic bile duct confluence. The visibility of the extrahepatic bile duct confluence was assessed against age, weight, and sedation and fasting states. RESULTS: The extrahepatic bile duct confluence was seen in 10 children out of 16 (62.5%). In the neonate sub-group (corrected age younger than 30 days), the MRCP was technically workable and the extrahepatic bile duct confluence was seen in four cases out of eight (50%). This visualization was up to 75% in the subgroup older than 30 days. However, statistically there was no significant difference in visibility of the extrahepatic bile duct confluence in relationship to age, weight or MRCP performance conditions (feeding, fasting or sedation). CONCLUSION: The complete normal biliary system (extrahepatic bile duct confluence included) is not consistently visualized in infants younger than 3 months old on non-enhanced MRCP. Thus the use of MRCP to exclude a diagnosis of biliary atresia is compromised at optimal time of surgery.

Chronic inflammatory diseases of the bowel: diagnosis and follow-up.

Approximately one fourth of cases of inflammatory bowel disease (IBD) occur during childhood and children are more prone than their adult counterparts to have severe disease at presentation. To investigate these diseases MR imaging is no longer an emerging tool. Numerous reviews and articles have been published on this topic underlying the advances of imaging but also the complexity and the financial impact on management of such diseases. In children it seems reasonable to consider US as the first imaging examination to perform, especially when the diagnosis of IBD is unknown. However, we believe that recent and future technical progress, especially the ability of MR to display reproducible data, and the need for gold standard evaluation of new medical therapies will increase the role of MR enterography.

[New formula for the determination od fetal age]. / Nouvelle formule de détermination de l'âge d'un foetus.

The methods utilised in anthropology for foetal age assessment are generally rather old, based on small samples and have never been tested on other samples than the one they were established on. In this study, we establish a formula on 344 foetuses of known age, and compare it with other age determination methods found in the scientific literature. Except our formula, the tested other methods do not give the limits of the prediction's confidence interval, and therefore do not take into account the total variability. Therefore, we demonstrate the necessity to establish formulas based on large samples and on a validated methodology.

Validation of a radiographic method to establish new fetal growth standards: radio-anatomical correlation.

In forensic medicine, specialists might face difficulties when estimating age at death from fetal remains. Depending on the state of preservation, this age assessment is essentially based on the diaphyseal size of long bones. In a previous work, for the measurement of fetal femoral ossified shafts, we already established a simple and reliable method using a radiographic protocol. Since we previously stated that radiographic measurement values were closer to real anatomical size than ultrasonographic ones, in the present study we decided to check the importance of the difference between radiographic and anatomical measurements. Therefore, we dissected 30 pairs of fetal femurs and compared the difference between the two kinds of measurements (in percentages). This difference seemed to be slight (4.027%), but it was large enough to entail significant differences (p < 0.001). In order to provide a correction factor for radiographic measurements, we established a linear regression formula, which was tested on another sample of 30 pairs of dissected femurs. As a consequence of the good results, we improved the linear regression using a powerful statistical tool: the bootstrap. Finally, we obtained a simple equation that allowed us to figure out the real anatomical size with an R2 of 99% and a mean relative difference of 0.153% (with a standard error of 0.252 mm, and therefore a 95% confidence interval with limits of -0.35 and 0.657 mm). This difference did not entail any significant differences (p = 0.498), and therefore, we concluded that with the proposed correction, radiographic measurements can easily be used by forensic specialists in their daily tasks or to establish new growth standards in order to best fit their population of interest.

Value of diagnosis imaging in the evaluation of the severity of histological lesions in duplex systems.

OBJECTIVE: In order to determine the effectiveness of imagery in the assessment of the severity of histological lesions in duplex systems in children we compared histology results from heminephrectomies with diagnosis imaging findings [renal ultrasound (US), scintigraphy, unenhanced and contrast-enhanced magnetic resonance imagery (MRI)]. MATERIALS AND METHODS: Between 2007 and 2013, 34 children with duplex system underwent surgery. The results from US (n = 34), dimer captosuccinic acid scintigraphy (n = 23) and MRI (n = 16) were compared with histological data. Five histological lesions were found (chronic interstitial inflammation, interstitial fibrosis, tubular atrophy, glomerulosclerosis and dysplasia) and categorized as severe (>25%) or moderate (≤ 25%). RESULTS: Severe histological lesions were found in 76.5% and moderate lesions in 23.5%. Radiological features were compared with histological results. In US, severe parenchymal thinning was associated with chronic interstitial inflammatory. The absence of parenchymal enhancement and/or severe cortical thinning in MR urography (MRU) was significantly associated with interstitial fibrosis. All poorly functioning poles were associated with severe histological lesions (p = 0.091), but not to a specific category of lesions. CONCLUSIONS: MRI sensibility was excellent (90%) in the diagnosis of poorly functioning pole. Severe thinning on US and minimal pole function on MRU can be used to predict the severity of histological lesions.

Sonographic diagnosis of a common pancreaticobiliary channel in children.

BACKGROUND: A common pancreaticobiliary channel is a very rare condition, but its diagnosis is of paramount importance since it can lead to complications that can be prevented. OBJECTIVE: To illustrate the sonographic diagnosis of a common pancreaticobiliary channel in children referred for abdominal pain or jaundice. MATERIALS AND METHODS: Four children were diagnosed by ultrasonography and the diagnosis was subsequently confirmed by MRI. RESULTS: Sonography demonstrated a pancreaticobiliary junction located in the pancreatic head above the sphincter of Oddi. This rare congenital anomaly was confirmed in all patients by MRI. CONCLUSION: A common pancreaticobiliary channel can be diagnosed by sonography. Nevertheless, our experience is limited, and although sonography can provide an alert and can assist management, it cannot yet replace MRI.