ABSTRACT
Objective To study the difference of image quality and radiation dose between different exposure modes with full-field digital mammography (FFDM).Methods The Fluke18-220mammographic phantom was exposed by FFDM system with different exposure modes at automatic exposure control ( AEC ) ,including contrast mode,standard mode and dose mode,and the exposure factors and radiation dose were recorded.The images on monitor with the best window width and window level were read by four independent radiologists.The images of specks groups,nylon fibers and masses was assessed by the four experienced readers at the criterion of American College of Radiology.Results The detection of specks groups,nylon fibers and masses were statistically different at the contrast mode and standard mode (F =41.321,P ＜ 0.05),further at the contrast mode and dose mode.The detection of specks groups、nylon fibers and masses were not statistically different( P ＞ 0.05 ) at standard mode and dose mode,but the radiation doses were different.The ESD at standard mode and dose mode was 4.5 and 3.15 mGy,respectively.The AGD of standard mode and dose mode was 1.18 mGy and 0.78 mGy,respectively.Conclusions The standard mode and dose mode of FFDM might be fit for most patients,especially at the dose mode.Contrast mode of FFDM should be strictly controled in use.
ABSTRACT
Objective To explore the diagnostic value of contrast-enhanced spiral CT after low tension and drinking water in papillary carcinoma of ampulla. Methods CT manifestations of papillary carcinoma of ampulla comfirmed pathologically in 20 cases were analysed retrospectively emphasized in artery phase on contrast CT which was performed after injecting 654-2 20 mg and drinking 300~500 ml water.Results Of all the cases , only 2 cases showed tumor filling defect in the descending part of duedenum nearby pancreas on routine CT, but all the cases showed more or less tumor filling defect on contrast-enhanced spiral CT . The diameters of the tumor were between 0.8 to 2.6 cm,2 cases with head of pancreas affected,the diameters of the tumor were between 2.4 to 2.6 cm.There were 2 cases with lymph node metastasis nearby duedenum.All the cases showed expansion of gallbladder ,intrahepatic duct and choledochus expanding in the liver. Conclusion Contrast-enhanced spiral CT after low tension and drinking water is superior to routine CT in determining the size and morphosis of tumor.
ABSTRACT
A retrospective study was carried out to analyze 3 cases of renal echinococcosis confirmed by surgery and pathology in the hospital during 1999-2008.The patients were examined by 64-CT plain scan and multiple period enhancement scan.Among them,2 were multi-daughter-cyst hydatid disease,and 1 appeared as solitary one.Two cases were once misdiagnosed as renal cyst and renal hamartoma,and the other was diagnosed correctly before operation.CT signscanning combined with epidemiological information can make an accurate diagnosis for renal echinococcosis.