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Objective: To explore the value of dual energy CT lung perfusion imaging (DEPI) for diagnosing pulmonary embolism (PE) in comparison with CT pulmonary angiography (CTPA). Methods: There were 49 patients with suspected PE received DEPI scanning and 19 with CTPA conifrmed diagnosis were enrolled in this study. CTPA image was obtained by 80 kv data, and DEPI image was obtained by PBV software. The location, type of PE in CTPA image, and the location, shape of perfusion defect in DEPI were observed and compared by segment basis. The correlation and agreement of CTPA and DEPI for diagnosing PE were calculated and the un-agreement was analyzed. Results: A total of 380 segments were included for analysis. CTPA detected 162 segments of PE and DEPI detected 155 segments of perfusion defect or reduction, partial PE were mainly presented by perfusion defects as speckles, patches or without perfusion defect, and complete PE were mainly showed segmental or sub-segmental perfusion defects. CTPA and DEPI were correlated for PE diagnosis (χ2=305.5,P=0.000), the diagnostic agreement was 83.42% and KAPPA value was 0.659. Conclusion: The perfusion defect in DEPI is related to the degree and type of PE presented in CTPA, their combination is helpful for diagnosing PE.
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Objective To compare the image quality and scanning dose of time-subtraction and dual-energy-subtraction cerebral CT angiography, and to assess clinical application value of both methods. Methods Plain and enhanced scanning were performed on 60 patients suspected cerebral vessel diseases with dual-source CT. Dual-energy mode with tube voltages of 140 and 80 kV was used in enhanced scanning, and data of two different energy were collected in one scanning. ①Traditional removed-bone digital subtraction (time-subtraction) with plain and 80 kV enhanced scanning data were obtained. Volume render (VR) and maximum intensity projection (MIP) reconstruction were finished; ②Direct removed-bone digital subtraction (dual-energy subtraction) with 80 kV and 140 kV enhanced scanning data were obtained. VR and MIP reconstruction were finished. The image quality of VR and MIP was divided into 4 grades, and were compared as well as average effective radiological dose. All the diseases were confirmed with surgery or DSA. Average effective radiological dose was compared with time-subtraction and dual-energy subtraction. Results Internal carotid artery trunk and branch and Willis circles were displayed clearly with two methods in 60 cases. No significant difference was found (P>0.05) between total quality score of the two methods. The size, shape, neck and axis point of aneurysm in 24 cases were clearly displayed, so as the shape and extent of abnormal vessel bolus in 4 cases, while arteries and veins were also clear in artery-vein malformation; ③The average radiological dose was (26.60±0.50)mSv in time-subtraction and (22.40±0.50) mSv in dual-energy subtraction. Conclusion The normal, abnormal vessels and diseases can be clearly displayed at time-subtraction and dual-energy subtraction CTA. The effect of dual-energy-subtraction is better than that of time-subtraction CTA in no-cooperation patients, and the radiological dose is lower in dual-energy CTA.
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Objective To assess the clinical value of HRCT in diagnosis of cholesteatomatous tympanitis.Methods HRCT findings of 26 patients with cholesteatomatous tympanitis proved by surgery and pathology were analyzed.Results HRCT findings of cholesteatomatous tympanitis included:soft tissue mass in the superior tympanium,tympanal sinus and mastoid(100%,26/26),destruction of the bone includeing ossicles chain (92%,24/26),secutum(46%,12/26),facial nerve canal (54%,14/26);enlargement of the tympaniosinus with sclerosing borders;intracranial complications including temple abscess(1 case),meningitis(1 case).Conclusion HRCT is of great value in diagnosis of cholesteatomatous tympanitis.