Can ultrasound be used as the primary imaging in children with suspected Crohn disease?

BACKGROUND: There is growing literature on the use of ultrasound (US) for evaluation of Crohn disease in adults, but few studies have been conducted on children. Several studies demonstrated high accuracy of US in the diagnosis of Crohn disease. Using US as the primary screening imaging modality for Crohn disease can reduce health care costs, the need for sedation and ionizing radiation exposure. OBJECTIVE: The aim of our study is to determine if US can be used for screening evaluation of pediatric Crohn disease. MATERIALS AND METHODS: A prospective cohort study of pediatric patients undergoing MR enterography (MRE) for suspected or known history of Crohn disease was performed, with gray-scale and Doppler US of the terminal ileum done immediately before or after MRE. US images were interpreted by two radiologists (Reader 1 and Reader 2) not involved in image acquisition, in blinded and randomized fashion. US findings of Crohn disease including bowel wall thickening, wall stratification, increased vascularity on Doppler, lymphadenopathy, fat infiltration and extraintestinal complications were evaluated. MRE findings of terminal ileitis were considered the reference standard. Demographic data, body mass index (BMI), symptoms, and laboratory, endoscopic and histopathological data were obtained from electronic medical records. RESULTS: Forty-one patients (mean age: 13.7 years: 4.6-18.9 years) were evaluated. Mean BMI was 21.2 (range: 13-40.2); 10 patients (24.3%) were either overweight or obese. Final diagnoses were Crohn disease (n=24), ulcerative colitis (n=4) and normal/non-inflammatory bowel disease-related diagnoses (n=13). US demonstrated sensitivity of 67% and 78% and specificity of 78% and 83%, by Reader 1 and Reader 2, respectively. MRE sensitivity and specificity were 75% and 100%, respectively, compared to final clinicopathological diagnosis. Interobserver agreement between Reader 1 and Reader 2 was good (0.6< kappa <0.8). CONCLUSION: In screening for Crohn disease in children, US has limited sensitivity for detecting terminal ileitis.

Modelling amorphous computations with transcription networks.

The power of electronic computation is due in part to the development of modular gate structures that can be coupled to carry out sophisticated logical operations and whose performance can be readily modelled. However, the equivalences between electronic and biochemical operations are far from obvious. In order to help cross between these disciplines, we develop an analogy between complementary metal oxide semiconductor and transcriptional logic gates. We surmise that these transcriptional logic gates might prove to be useful in amorphous computations and model the abilities of immobilized gates to form patterns. Finally, to begin to implement these computations, we design unique hairpin transcriptional gates and then characterize these gates in a binary latch similar to that already demonstrated by Kim et al. (Kim, White & Winfree 2006 Mol. Syst. Biol. 2, 68 (doi:10.1038/msb4100099)). The hairpin transcriptional gates are uniquely suited to the design of a complementary NAND gate that can serve as an underlying basis of molecular computing that can output matter rather than electronic information.