ABSTRACT
<p><b>BACKGROUND</b>Colonic polyps are frequently encountered in clinics. Computed tomographic colonography (CTC), as a painless and quick detection, has high values in clinics. In this study, we evaluated the application value of computer-aided detection (CAD) in CTC detection of colonic polyps in the Chinese population.</p><p><b>METHODS</b>CTC was performed with a GE 64-row multidetector computed tomography (MDCT) scanner. Data of 50 CTC patients (39 patients positive for at least one polyp of ≥ 0.5 cm in size and the other 11 patients negative by endoscopic detection) were retrospectively reviewed first without computer-aided detection (CAD) and then with CAD by four radiologists (two were experienced and another two inexperienced) blinded to colonoscopy findings. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of detected colonic polyps, as well as the areas under the ROC curves (Az value) with and without CAD were calculated.</p><p><b>RESULTS</b>CAD increased the overall sensitivity, specificity, positive predictive value, negative predictive value and accuracy of the colonic polyps detected by experienced and inexperienced readers. The sensitivity in detecting small polyps (5 - 9 mm) with CAD in experienced and inexperienced readers increased from 82% and 44% to 93% and 82%, respectively (P > 0.05 and P < 0.001). With the use of CAD, the overall false positive rate and false negative rate for the detection of polyps by experienced and inexperienced readers decreased in different degrees. Among 13 sessile polyps not detected by CAD, two were ≥ 1.0 cm, eleven were 5 - 9 mm in diameter, and nine were flat-shaped lesions.</p><p><b>CONCLUSIONS</b>The application of CAD in combination with CTC can increase the ability to detect colonic polyps, particularly for inexperienced readers. However, CAD is of limited value for the detection of flat polyps.</p>
Subject(s)
Adult , Aged , Female , Humans , Male , Middle Aged , Young Adult , Colonic Polyps , Diagnosis , Diagnostic Imaging , Colonography, Computed Tomographic , Methods , Retrospective Studies , Sensitivity and SpecificityABSTRACT
Gene chip technology was employed to study gene expression in Tamarix androssowii under NaHCO3 stress. cDNAs from T. androssowii treated with NaHCO3 solution and that from control group were labeled with fluorescent dye CyS and Cy3 respectively. The two fluorescent cDNA probes were mixed and hybridized to gene chips containing T. androssowii genes, and the chips were scanned using biochip scanning system. Differential expression of genes was analyzed through calculation of the ratio of Cy5 to Cy3 signal intensities. Total of 89 genes differentially expressed were identified, among them, 27 showed down regulated expression and 62 showed up regulated expression. Blastx analysis showed that the function of the differentially expressed genes could be grouped into some categorizations such as photosynthesis, reactive oxygen species eliminated, regulation of osmotic potential, regulation of gene expression and signal transduction, metabolism, development, ribosomal protein, protein breakdown and recycling, transporter, water channel proteins and so on. Based on this research, some function-unknown or novel unreported genes that respond to salt stress were also identified, and these genes may have important functions in salt resistance of T. androssowii. Some important pathways of salt resistance in T. androssowii are revealed, and the gene expression profiling of T. androssowii under salt stress and without stress is obtained in this study.