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This study introduced a time-delay exposure system independent of the mobile digital radiography equipment. The system consisted of lithium battery, delay control circuit, micro electric motor and related auxiliary facilities. When the starting time was reached through the delay circuit, the motor pushed out the rod to squeeze the exposure button and completed the exposure. The accessories used in this system were easy to purchase and cheap. At the same time, the technology was mature and had good compatibility. The exposure success rate was high and the exposure effect was satisfactory. This time-delay exposure system had good practicability and popularization value.
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Intensificação de Imagem Radiográfica , Tecnologia , Fontes de Energia ElétricaRESUMO
BackgroundPrevious studies have showed clinical characteristics of patients with the 2019 novel coronavirus disease (COVID-19) and the evidence of person-to-person transmission. Limited data are available for asymptomatic infections. This study aims to present the clinical characteristics of 24 cases with asymptomatic infection screened from close contacts and to show the transmission potential of asymptomatic COVID-19 virus carriers. MethodsEpidemiological investigations were conducted among all close contacts of COVID-19 patients (or suspected patients) in Nanjing, Jiangsu Province, China, from Jan 28 to Feb 9, 2020, both in clinic and in community. Asymptomatic carriers were laboratory-confirmed positive for the COVID-19 virus by testing the nucleic acid of the pharyngeal swab samples. Their clinical records, laboratory assessments, and chest CT scans were reviewed. FindingsNone of the 24 asymptomatic cases presented any obvious symptoms before nucleic acid screening. Five cases (20.8%) developed symptoms (fever, cough, fatigue, etc.) during hospitalization. Twelve (50.0%) cases showed typical CT images of ground-glass chest and 5 (20.8%) presented stripe shadowing in the lungs. The remaining 7 (29.2%) cases showed normal CT image and had no symptoms during hospitalization. These 7 cases were younger (median age: 14.0 years; P = 0.012) than the rest. None of the 24 cases developed severe COVID-19 pneumonia or died. The median communicable period, defined as the interval from the first day of positive nucleic acid tests to the first day of continuous negative tests, was 9.5 days (up to 21 days among the 24 asymptomatic cases). Through epidemiological investigation, we observed a typical asymptomatic transmission to the cohabiting family members, which even caused severe COVID-19 pneumonia. InterpretationThe asymptomatic carriers identified from close contacts were prone to be mildly ill during hospitalization. However, the communicable period could be up to three weeks and the communicated patients could develop severe illness. These results highlighted the importance of close contact tracing and longitudinally surveillance via virus nucleic acid tests. Further isolation recommendation and continuous nucleic acid tests may also be recommended to the patients discharged.
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Objective:To investigate the magnetic resonance imaging (MRI) features of Cryptococcus infection in central nervous system patients with acquired immune deficiency syndrome (AIDS).Methods:The retrospective study on magnetic resonance imaging (MRI) and clinical data of cryptococcal meningitis (CM) was carried out between July 2011 and March 2017.These patients had not received anti-retroviral treatment.Patients with other specific or suspicious diseases in the central nervous system were not included in the analysis.Results:A total of 39 patients were included in the analysis,with CD4 cell counts of 13.0×106/L [(0-205)×106/L],and 94.9％ (37/39) of patients with CD4 cell count ＜100×106/L.Of the 39 patients,26 patients showed abnormal MRI signals in the brain,which were most frequently involved in the basal ganglia (20/26,76.9％).The basal ganglia lesions showed dilated VirchowRobin space (VRS)/gelatinous spseudocysts (18/20,90％).Postcontrast T 1-weighted MRI revealed no significant enhancement (3/5,60％) and mild enhancement (2/5,40％).The incidence of cerebral cryptococcal granuloma were 35％ (7/20).Nineteen of 26 patients with lesions outside the basal ganglia,of which 13 patients also complicated with basal ganglia lesions.Postcontrast T1-weighted MRI revealed no significant enhancement.The incidence of cryptococcal granuloma and meningeal thickening were 15.7％ (3/19) and 26.3％ (5/19),respectively.Postcontrast T1-weighted MRI meningeal thickening revealed enhancement (5/5,100％).Conclusion:The incidence of brain MRI abnormality in AIDS complicated with central nervous system Cryptococcus infection may not be low,and the lesions are mostly located in the basal ganglia.It most frequently displays the dilated VRS/gelatinous spseudocysts.It can also be showed cryptococcal granuloma.Postcontrast T1-weighted MRI often reveals no enhancement or mild enhancement.
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Objective To studying the MR findings and pathology of peripheral small intrahepatic cholangiocarcinoma and improving the understanding of peripheral small cholangiocarcinoma with no-bile duct dilatation. Methods A retrospective analysis of 12 patients with intrahepatic peripheral cholangiocarcinoma which were confirmed by surgery and pathology, all patients were examined by abdominal MRI without and with contrast. Correlation was made with gross pathology and surgical pathological specimen. Results On T1WI, there were 4 cases of complex low signal intensity and 8 cases of low signal intensity. On T2WI, there were 8 cases of high signal intensity and 4 cases of complex high signal intensity. Enhanced MRI showed: marked nidus enhancement on arterial phase in 1 case, and the pathological diagnosis was poorly differentiated adenocarcinoma. Inhomogeneous enhancement or annular enhancement were seen in 10 cases on arterial phase, 3 of these cases showed thin annular enhancement on arterial phase, low signalintensity on portal venous phase and isointensity on delayed phase. One case showed delayed enhancement. Thick circular enhancement correlated with pathological changes of survival of tumor cells, center areas correlated with fibrous connective tissue, and a small amount of necrotic tissue. Island-like enhancement or inhomogeneous enhancement were seen in 3 cases. Corresponding pathological changes consisted of tumor tissue and a small amount of fibrous connective tissue, as well as somenecrotic tissue. In 1 case, no enhancement was seen on all three phases and pathological changes showed cystic changes, hemorrhage, necrosis, with survival tumor cells seen between cyst and normal liver tissue. Conclusions MRI scanning of peripheral small cholangiocarcinoma lacked characteristic features, but dynamic contrast-enhanced MR had certain specific findings. Due to different pathology, the fibrous tissue, necrotic tissue and survival tumor tissue components were exhibited different imaging findings.
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Objective To compare the efficacy of MRI and multi-slice CT(MSCT) for characterization of liver isolation nodular lesions in cirrhosis patients .Methods A total of 64 patients with 64 lesions ,underwent MSCT and MRI .Chi-square tests were used to compare the performances of MSCT and MRI in characterization of lesions .Results The detection rate ,accuracy ,sensitivity ,spe-cificity ,positive predictive and negative predictie of MSCT and MRI were 76 .56% ,65 .31% ,37 .50% ,78 .79% ,72 .22% ,46 .15%and 87 .50% ,85 .71% ,66 .67% ,97 .14% ,82 .93% ,93 .33% respectively .There were statistical difference in accuracy ,specificity , positie predictie between MSCT and MRI (P< 0 .05) .Conclusion MRI is superior to MSCT in accuracy ,specificity ,and positive predictive for characterization of liver isolation noduler lesions .
