| Objective：The adrenal gland is one of the most important endocrinegland in the body, adrenal disease often leads to a series of serious endocrinedisorders. The adrenal adenomas and metastases are the most common inclinic, but the clinical treatment of the two is different, therefore, the correctdifferential diagnosis has direct guiding significance to the clinical treatment.This study analyzed by energy spectrum CT image of adrenal adenomas frommetastases, to explore the application of energy spectrum CT in thedifferential diagnosis of adrenal adenomas from metastases, and also providescientific basis for adrenal benign and malignant lesions in the early diagnosisand differential.Methods： Retrospective analysis33patients from March2012toDecember2013with adrenal diseases in our hospital, a total of40adrenalnodules: including18cases of adrenal adenoma patients, a total of20nodules(8male and10female, aged27~70years, mean age44.5years);15cases withadrenal metastatic tumors, a total of20nodules (5female and10male, age49~85years, mean age61.3years). All inspection are in the GE DiscoveryCT750HD64slice dual energy CT scans use the energy spectrum scanningmode (GemStone Imaging, GSI), the adrenal area targeted scan, includingplain and dynamic enhanced scan, dynamic enhanced scanning includingarterial phase, portal venous phase and delayed phase. Each phase scanningsingle energy image (Mono) using standard reconstruction, layer thickness andlayer spacing both are0.625mm.On the professional workstation GE AW4.4into the GSI observation and analysis system (GSI viewer), respectively, wereobserved and measured the spectrum image in each period of single energyimage. Placed the focus region of interest (ROI), kept by the automaticanalysis system for the drawing of ROI spectrum curves and data file, the data file contains40~140keV (10keV intervals) of each energy level of CT value(HU), each paired base material concentration (mg/ml)(water-calcium,calcium-water, fat-iodine and iodine-fat and water-iodine, iodine-waterthree pairs) and the effective atomic number (Effective-Z) measurement.Compare the routine indexes of two groups on plain scan, including patientage, tumor maximum diameter, whether or not sublobe, the boundary is clearor not, whether or not calcification and necrosis and adjacent structuresinvasion; comparison the of characteristics of plain scan and the enhancementscanning groups in the different energy, content of the base material and theeffective atomic number. Then use SPSS13.0software, means and standarddeviations were analyzed by descriptive analysis, and homogeneity ofvariance test, variance alike using analysis of variance; If not use rank sumtest. The measurement data such as cortical adenoma and metastasis groupunder the scan and enhance every period of40~140kev CT value, energyspectrum curve slope, the Effective Z, concentration measurement and so onusing independent sample t test, P <0.05for the difference has significantmeaning.Results：In plain scan,20cases of adrenocortical adenoma group showedround or oval mass, boundary clear or clearer, more uniform density, noliquefaction, no necrosis, no calcification and no hemorrhage, the largestvolume is about32.5X21.0X22.8mm, the smallest volume is about10.7X8.4X7.6mm.8cases of metastatic tumor group in20cases showedround or oval mass, complete capsule, with clear border,12cases showedirregular shape, the boundary is not clear; the lesions of11cases withliquefaction necrosis,9cases of non liquefaction necrosis;20lesions were nocalcification, hemorrhage, the largest volume is about43.5X32.9X45.2mm,the smallest volume is about6.0X8.4X5.6mm. Enhancement scanning, adrenalcortical adenoma showed mild to moderate homogeneous enhancement,inarterial phase enhanced obviously, portal venous phase and delayed phaseenhancement degree decreased obviously; adrenal metastases wassignificantly enhanced in the arterial phase, but the portal venous phase and delayed phase enhancement degree of decline is slow than the adenoma,including11cases containing liquid necrosis, which are inhomogeneousenhancement, solid part was obvious enhanced, and liquefaction necrosis partwas not obvious enhanced.Plain scan of the energy spectrum CT, energy of mixing shows that theaverage CT of adenoma was about10.11±13.64HU, and metastatic was about22.28±13.50HU, the difference was statistically significant between the two(t=-2.578，p=0.015). Adrenal adenomas from metastases in11different singleenergy CT those values40~140(in intervals of10)were statisticallysignificant difference, P were less than0.05, and the difference is more bigwith the energy lower, the most striking difference is in40Kev (t=-4.938, p=0.000).The energy spectrum curve shape is different, metastasis groupspectrum curve showed a decreasing type; adenoma group spectrum curve riseor decline slowly, the down slope less than metastasis group. The spectralanalysis of arterial phase image, both the curve form was decreased, but thedecreasing slope are different; and in the analysis of different single energy,with the energy raising their differences was more obvious, but there were nostatistically significant differences in the40~60Kev (40Kev, t=-0.833,p=0.413;50Kev, t=-1.295, p=0.207;60Kev, t=-1.849, p=0.076), in70~140Kev, there were significant differences between the two groups(P <0.05); statistical results of the experiments showed that the metastatic tumorgroup in each single energy average CT values were higher than adenomagroup, the degree of enhancement of metastatic tumor were higher than theadenoma. The spectrum analysis of the portal venous phase images, corticaladenoma group and metastatic tumor group image both are declining, CTvalues metastasis group in every single energy value is still higher than theadenoma group, the difference in every single energy were statisticallysignificant, P were less than0.05, and in the single energy of100Kev thedifferences was most significant (t=-3.382, p=0.002). Delayed phase scanningshowed two groups of curve shape are declining, adenoma group each singleenergy CT value is lower than the metastatic tumor group, and each single energy the difference has significant difference, P were less than0.05. Theeffective atomic number of metastasis group (7.73±0.12) was higher than thatof adenoma group (7.44±0.27), the difference was statistically significantbetween the two (t=-3.347, P=0.003); each paired base material in tumorgroup (water-calcium, calcium-water, iodine-fat, fat-iodine,water-iodine,iodine-water) were higher than the adenoma group, each difference hasstatistical significance.Conclusions：1Adrenocortical adenoma and metastases have some differences in ageand tumor size, energy spectrum CT is beneficial to diagnosis by single energyimaging, base material and the effective atomic number;2Plain scan of the energy spectrum CT, the energy spectrum curve shapeis different, metastasis group spectrum curve showed a decreasing type,adenoma group spectrum curve rise or decline slowly, the down slope lessthan metastasis group.3The spectral analysis of dynamic enhanced scan image, both the curveform was decreased, but the decreasing slope is different. |
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