Contrast-enhanced ultrasound in the assessment of Crohn's disease activity: comparison with computed tomography enterography.

BACKGROUND AND OBJECTIVE: Continuous assessment of disease activity remains a huge challenge during the follow-ups of patients with Crohn's disease (CD). In this paper, we aimed to evaluate the performance of contrast-enhanced ultrasound (CEUS) by comparing with computed tomography enterography (CTE) in the assessment of disease activity in CD. MATERIALS AND METHODS: Fifty-two patients diagnosed with CD were included in this study, using the CEUS and CTE as imaging methods for comparison. The selected parameters included the location and thickness of the thickest part of the intestinal wall, mesenteric fat proliferation, mesenteric vessels change, enhancement pattern and the presence of complications. Patients were clinically assessed using the Crohn's disease activity index (CDAI), C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). Simple endoscopic score for Crohn's disease (SES-CD) was regarded as the reference standard. RESULTS: The location of the thickest part of the intestinal wall (κ = 0.653), bowel wall thickness (ICC = 0.795), mesenteric vessels change (κ = 0.692) and complications (κ = 0.796) displayed substantial agreement (0.61-0.80) between CEUS and CTE, while the detection of mesenteric fat proliferation (κ = 0.395) and enhancement pattern (κ = 0.288) showed fair consistency (0.21-0.40) for comparison. In CEUS, bowel wall thickness, mesenteric fat proliferation, enhancement pattern and mesenteric vessels change were statistically significant in assessing CD activity, while bowel wall thickness, mesenteric fat proliferation and mesenteric vessels change in CTE. Bowel wall thickness showed the best diagnostic performance in the assessment of CD activity at CEUS and CTE. CONCLUSION: CEUS provides a radiation-free and effective way to assess the CD activity in comparison with CTE, which also avoids frequent colonoscopy examinations, improves tolerance of patients, and reduces the cost of medical care, thereby serving as a useful tool for CD follow-up.

Usefulness of Strain Elastography, ARFI Imaging, and Point Shear Wave Elastography for the Assessment of Crohn Disease Strictures.

OBJECTIVES: The aim of this study was to evaluate the diagnostic performance of strain elastography, acoustic radiation force impulse (ARFI) imaging and point shear wave elastography (p-SWE) for assessment of the predominant types of intestinal stenosis in Crohn disease. METHODS: Twenty-five patients were enrolled in this study, among whom 25 suspicious stenoses in 25 intestinal segments were studied using gray scale ultrasonography. All 3 elastography methods were performed, and all patients underwent endoscopy within 24 hours with pathologic biopsy. The sensitivity, specificity, accuracy, positive predictive value (PPV), negative predictive value (NPV), Youden index, and area under the receiver operating characteristic curve (AUROC) were calculated. Pathologic findings were regarded as the gold standard. RESULTS: For SE, the optimal cutoff value was a score of 4 or greater (sensitivity, 75%; specificity, 66.7%; accuracy, 68%; PPV, 30%; NPV, 93.3%; AUROC, 0.708; however, P > .05). The results of ARFI imaging were similar: the optimal cutoff value was a score of 4 or greater (sensitivity, 50%; specificity, 81%; accuracy, 76%; PPV, 33.3%; NPV, 89.4%; AUROC, 0.669; P < .05). However, for p-SWE, the optimal cutoff value was reached when the shear wave velocity exceeded 2.73 m/s (sensitivity, 75%; specificity, 100%; accuracy, 96%; PPV, 100%; NPV, 95.5%; AUROC, 0.833; P < .05). CONCLUSIONS: p-SWE had the best performance for evaluating and differentiating intestinal stenosis in Crohn disease, while neither SE nor ARFI imaging achieved satisfactory outcomes for evaluating inflammatory stenosis and fibrotic stenosis of Crohn disease.

The development and evaluation of a sub-health self-rating scale for university students in China.

BACKGROUND: Sub-health status is defined as declines in vitality, physiological function and capacity for adaptation, but without the presence of clinical or sub-clinical disease. We have developed and evaluated a comprehensive questionnaire, the Sub-Health Self-Rating Scale (SSS), to assess sub-health status in university students. METHOD: The items for the draft questionnaire were discussed in focus groups. The WHOQOL-BREF was selected as the validity reference. From a professional perspective and large sample evaluation, the scale ultimately consisted of 58 items. The reliability and validity of the SSS was examined in undergraduate students and 1000 questionnaires were randomly selected from the samples for expert evaluation. RESULTS: Cronbach's α of the total scale was 0.942. The dimensions of physiological, psychological and social had high reliability: 0.915, 0.856 and 0.850, respectively. Based on scree plot and related theories, there were 10 factors to be extracted. The correlation coefficient between the total scale and sub-scale was high. The dimensions of physiological, psychological and social had high correlations with the total scale: 0.929, 0.803 and 0.774, respectively. The sub-health cut-off point of the total scale was 72; for the physiological field, it was 72; for the psychological field, it was 60; and the social field, it was 56. The fit between the expert evaluation method and the scale method was 0.758. The lower the score, the worse the health condition. CONCLUSION: We established and evaluated a valid instrument (SSS) that encompasses physiological, psychological and social factors to investigate sub-health status. It is short and easy to complete, and therefore suitable for use with undergraduate students.

[Assessment of shallow groundwater nitrate concentrations in typical terrestrial ecosystems of Chinese Ecosystem Research Network (CERN) during 2004-2009].

The nitrate-N (NO3(-) -N) concentrations of 38 shallow groundwater wells from 31 of the typical terrestrial ecosystems on Chinese Ecosystem Research Network (CERN) were assessed using the monitoring data from 2004 to 2009. The results showed that the average values of NO3(-) -N concentrations were significantly higher in the agricultural (4.85 mg x L(-1) +/- 0.42 mg x L(-1)), desert (oasis) (3.72 mg x L(-1) +/- 0.42 mg x L(-1)) and urban ecosystems (3.77 mg x L(-1) 0.51 mg x L(-1)) than in the grass (1.59 mg x L(-1) +/- 0.35 mg L(-1)) and forest ecosystems (0.39 mg x L(-1) +/- 0.03 mg x L(-1)). Nitrate was the major form of nitrogen, with between 56% to 88% of nitrogen in the nitrate-N form in the shallow groundwater of desert (oasis), urban and agricultural ecosystems. Nitrate-N concentrations for some agricultural ecosystems (Ansai, Yanting, Yucheng) and desert (oasis) ecosystems (Cele, Linze, Akesu) analysis exceeded the 10 mg x L(-1) World Health Organization drinking water standards between 14.3% and 84.6%. Significant seasonality was found in Ansai, Fengqiu, Yanting agricultural ecosystems and the Beijing urban ecosystem using the relatively high frequency monitoring data, with the higher nitrate concentrations usually found during summer and winter months. The monitoring results indicated that the shallow groundwater of agricultural ecosystems was contaminated by agricultural management practices, i.e. fertilization, while the shallow groundwater of forest ecosystems was under natural condition with no contamination from human activities.

[Effects of CO2 storage flux on carbon budget of forest ecosystem].

Carbon dioxide (CO2) storage flux in the air space below measurement height of eddy covariance is very important to correctly evaluate net ecosystem exchange of CO2 (NEE) between forest ecosystem and atmosphere. This study analyzed the dynamic variation of CO2 storage flux and its effects on the carbon budget of a temperate broad-leaved Korean pine mixed forest at Changbai Mountains, based on the eddy covariance flux data and the vertical profile of CO2 concentration data. The CO2 storage flux in this forest ecosystem had typical diurnal variation, with the maximum variation appeared during the transition from stable atmospheric layer to unstable atmospheric layer. The CO2 storage flux calculated by the change in CO2 concentration throughout a vertical profile was not significantly different from that calculated by the change in CO2 concentration at the measurement height of eddy covariance. The NEE of this forest ecosystem was underestimated by 25% and 19% at night and at daytime, respectively, without calculating the CO2 storage flux at half-hour scale, and was underestimated by 10% and 25% at daily scale and annual scale, respectively. Without calculating the CO2 storage flux in this forest ecosystem, the parameters of Michaelis-Menten equation and Lloyd-Taylor equation were underestimated, and the ecosystem apparent quantum yield (alpha) and the ecosystem respiration rate (Rref) at the reference temperature were mostly affected. The gross primary productivity (GPP) and ecosystem respiration (Re) of this forest ecosystem were underestimated about 20% without calculating the CO2 storage flux at half-hour, daily scale, and annual scale.