Application of computed tomographic colonography in diagnosis of colonic polyps / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To assess the clinical values of computed tomographic colonography (CTC) in diagnosis of colonic polyps.</p><p><b>METHODS</b>Forty-two patients who were clinically suspicious of colonic polyps or underwent colonic polyps screening received examinations with both CTC and conventional colonoscopy. Sixteen- or 64-slice spiral computed tomography and professional imaging processing techniques were used for evaluation. Per-polyp and per-patient results were analyzed. Those by per-polyp were subsequently divided into > or = 10 mm group, 5-10 mm group, and < or =5 mm group. Sensitivity, positive predictive value (PPV), specificity, negative predictive value (NPV), and accuracy were calculated using statistical method for diagnostic studies, with conventional colonoscopy as a gold standard.</p><p><b>RESULTS</b>Ninety and 61 polyps were found by CTC and conventional colonoscopy, respectively. The per-polyp sensitivity/PPV were 80.3%/55.6% in total, and 100%/92.9%, 93.8%/65.2%, and 68.8%/ 41.5% in the > or = 10 mm group, 5-10 mm group, and < or =5 mm group, respectively. The per-patient sensitivity, PPV, specificity, NPV, and accuracy were 97.1%, 89.5%, 42.9%, 75.0%, and 88.1%, respectively.</p><p><b>CONCLUSION</b>CTC can clearly reveal the morphology of colonic polyps and be used as a routine monitoring method for the clinical diagnosis of polyps.</p>

Assessment of coronary stents by 64-slice computed tomography: in-stent lumen visibility and patency / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To assess lumen visibility of coronary stents by 64-slice computed tomography (CT) coronary angiography, and determine the value of 64-slice CT in non-invasive detecting of in-stent restenosis after coronary artery stent implantation.</p><p><b>METHODS</b>Totally, 60 patients (54 males, aged 57.0+/-12.7 years) and 105 stents were investigated by 64-slice CT at a mean interval of 20.0+/-16.6 months after coronary stents implantation. Axial multi-planar reconstruction images of the stents and curved-planar reconstruction images through the median of the stents were reconstructed for evaluating stent image quality on a 5-point scale (1=excellent, 5=non-assessable), and stent lumen diameter was detected. Conventional coronary angiography was performed in 18 patients, and 32 stents were evaluated.</p><p><b>RESULTS</b>Image quality was good to excellent on average (score 1.71+/-0.76). Stent image quality score was correlated to heart rate (r=0.281, P<0.01) and stent diameter (r=-0.480, P<0.001). All the stents were assessable in lumen visibility with an average visible lumen diameter percentage of 60.7%+/-13.6%. Visible lumen diameter percentage was correlated to heart rate (r=-0.193, P<0.05), stent diameter (r=0.403, P<0.001), and stent image quality score (r=-0.500, P<0.001). Visible lumen diameter percentage also varied depending on the stent type. In comparison with the conventional coronary angiography, 4 of 6 in-stent stenoses were correctly detected. The sensitivity and specificity for the detection of in-stent stenosis were 66.7% and 84.6%, respectively.</p><p><b>CONCLUSIONS</b>Using a 64-slice CT, the stent lumen is partly visible in most of the stents. And 64-slice CT may be useful in the assessment of stent patency.</p>

Radiological features of dual-energy CT lung perfusion imaging in patients with acute pulmonary embolism: comparison with CT pulmonary angiography / 中国医学科学院学报

<p><b>OBJECTIVE</b>To explore the relationship of the perfusion defects in the dual-energy CT lung perfusion image and the filling defects in the CT pulmonary angiography (CTPA) in patients with acute pulmonary embolism.</p><p><b>METHODS</b>The clinical data of 22 patients with acute pulmonary embolism were retrospectively analyzed. All of them underwent contrast CT scan in two phases using dual-energy CT: the first is pulmonary artery phase, and the second was performed immediately after the first phase using dual-energy scan covered the whole lung. Perfusion defects in the lung perfusion images were compared with the filling defects in the CTPA.</p><p><b>RESULTS</b>Complete filling defects of segmental and subsegmental pulmonary arteries mostly showed correspondence perfusion defects in the CT perfusion map, accounting for 83% and 62% respectively. However, when there were partial or central filling defects, most of them were partial perfusion defects or normal in the CT perfusion map. Three segmental perfusion defects were depicted without the visualization of endoluminal thrombi within the corresponding arteries.</p><p><b>CONCLUSIONS</b>The perfusion defects in the CT lung perfusion image are not completely corresponding to the filling defects in the CTPA. The combination of CTPA and CT lung perfusion map will offer more information for the acute pulmonary embolism.</p>

Optimal Conditions and Validation of Single-strand Conformation Polymorphism Technology for the Analysis of Microbial Communities in Activated Sludge / 微生物学通报

Single-Strand Conformation Polymorphism(SSCP) is an effect method for investigating environment microbial genetic polymorphism, with its characterization of rapidness, simplicity, and sensitivity. However, many factors can influence the results of SSCP in the analysis of complex environment samples, and its optimization is highly needed. In this paper, optimal PCR-SSCP conditions were discussed based on PAGE concentration, formamide deionized in denaturing loading buffer, electrophoresis time and temperature. The resluts showed that the optimal conditions were as follows: 16S rDNA V1~V3 was selected as the targeted gene, the ratio of acrylamide to N, N-dimethylacrylamide in 12% polyacrylamide gel electrophoresis(PAGE)gel was 49:1, the ratio of formamide deionized in denaturing loading buffer was 1:3, running the SSCP gel at 300 V for 18 h (under 4 ℃). Aside from this, the validations using samples from a simultaneous desulfurification and denitrification bioreactor were conducted under this optimal conditions.

CT perfusion in evaluation of cerebral hemodynamics in carotid artery stenosis / 中国医学科学院学报

<p><b>OBJECTIVE</b>To study the clinical value of multi-slice spiral CT (MSCT) perfusion technique in evaluation of cerebral hemodynamics in patients with severe carotid stenooclusive lesions.</p><p><b>METHODS</b>Twenty-three patients with severe carotid stenosis were enrolled for evaluation of cerebral hemodynamics, including 12 patients with carotid occlusion and 11 with severe carotid stenosis (> 70%). Among them, 16 patients had multiple arterial diseases, including contralateral carotid stenosis, vertebral arteries stenosis, and cerebral arteries stenosis or occlusion. All patients received CT perfusion examination. Ten normal persons received CT perfusion were regarded as the control group.</p><p><b>RESULTS</b>Cerebral perfusion was bilaterally symmetrical in 10 normal persons. While in the patients group, cerebral hemodynamic impairments ipsilateral to the stenosis side were found by CT perfusion in 17 patients, including an delay of time to peak (TTP) (17 patients), increase of cerebral blood volume (CBV) (7 patients), and decrease of cerebral blood flow (CBF) (4 patients). No significant difference was found between occlusion group (n = 8) and stenosis group (n = 9) (P = 0.640), but incidences of hemodynamic impairment were significantly higher in multiple arterial diseases group (n = 14) than single arterial disease group (n = 3) (P = 0.045).</p><p><b>CONCLUSION</b>CT perfusion technique can sensitively reveal the cerebral hemodynamic impairments in patients with severe carotid stenooclusive diseases, and therefore valuable for clinical application.</p>

Application of multi-slice spiral CT in the diagnosis of pulmonary hypertension / 中国医学科学院学报

<p><b>OBJECTIVE</b>To evaluate the utility of multi-slice spiral CT in the diagnosis of pulmonary hypertension.</p><p><b>METHODS</b>The clinical and multi-slice spiral CT data of 22 patients with pulmonary hypertension were retrospectively analyzed. The diagnoses included chronic thromboembolic pulmonary hypertension (CTEPH) (n = 9), primary pulmonary hypertension (PPH) (n = 7), connective tissue diseases (n = 2), portal-pulmonary hypertension (n = 2), eosinophilia-myalgia syndrome (n = 1), and fibrosing mediastinitis (n = 1). Lung parenchyma, such as ground-glass opacity, mosaic attenuation and septal thickness, mediastinum, pulmonary vascular, right ventricular enlargement and interventricular septum displacement were evaluated on CT.</p><p><b>RESULTS</b>CT pulmonary angiography (CTPA) accurately diagnosed 95% of pulmonary hypertension and the signs of right ventricular dysfunction. Pulmonary embolism was found in 9 patients. The incidence of mosaic attenuation was significantly higher in CTECH than in PPH (P = 0.034).</p><p><b>CONCLUSION</b>CTPA can accurately diagnose pulmonary hypertension and thereby provide useful information for the etiological diagnosis.</p>

Using of multislice helical CT colonography in patients with malignant lesions of colon / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the techniques and clinical applications of multislice helical computed tomography (CT) colonography in colonic lesions.</p><p><b>METHODS</b>Fifty-nine patients with malignant lesions of colon underwent volume scanning using multislice helical CT. Four types of reconstruction including CT virtual colonoscopy (CTVC), shaded surface display (SSD), Raysum, and multiple planar reconstruction (MPR) were used for image post-processing. The results were compared with those of colonoscopy and pathology.</p><p><b>RESULTS</b>Multislice helical CT colonography detected 54 colorectal carcinomas, 4 adenomas with focal carcinoma, 1 non-Hodgkin's lymphoma (NHL). The lesions' number, size, location, morphology, stricture of intestinal cavity, infiltration, and metastasis were shown satisfactorily by multislice helical CT colonography. Whole colon could be shown in all patients. CT colonography displayed 4 synchronous colonic tumors, 1 ascending colon carcinoma combined with left renal carcinoma among 54 patients with colonic carcinomas. The accuracy of location of CT colonography was 100%. There were 9 cases that CT showed the tumor location was different from the finding of conventional colonoscopy, while all of the CT location were proven exact by operation. CT colonography also displayed the infiltration of serous layer and fatty tissue in 45 cases; 21 cases matched the pathological results in all the 24 cases of suspicious lymph node metastasis, the sensitivity was 87.5%, the specificity was 90.6%; 9 cases hepatic metastasis, 2 ovarian metastasis, and 1 double adrenal gland metastasis.</p><p><b>CONCLUSIONS</b>Multislice helical CT colonography is effective in preoperative diagnosis, location, stage, and making treatment plan of colorectal carcinoma. It can display the portion not seen during colonoscopy and may have an adjunctive role.</p>

Techniques and clinical applications of 16 multislice helical CT in colonic diseases / 中国医学科学院学报

<p><b>OBJECTIVE</b>To evaluate the techniques and clinical applications of 16 multislice helical CT in colonic lesions.</p><p><b>METHODS</b>Eighty-one patients including 54 colorectal carcinomas, 5 adenomas, 1 non-Hodgkin's lymphoma, 6 inflammatory bowel diseases, and other 15 cases underwent volume scanning using 16 multislice helical CT. Four types of reconstruction included multiple planar reconstruction, shaded surface display, raysum, and CT virtual colonoscopy.</p><p><b>RESULTS</b>Complete colon could be shown in all patients. The lesions' morphology, number, size, location, intestinal cavity, pericolonic changes, and other abdominal organs were satisfactorily shown by CT.</p><p><b>CONCLUSIONS</b>Sixteen multislice helical CT colonography is a valuable imaging technique for detecting colonic diseases. It is effective in diagnosis and treatment planning. It can display the portions of colon that is inaccessible at colonoscopy.</p>