以ACR-156模型评价数字乳腺断层融合X线成像对乳腺模拟病灶的显示能力

Evaluation on the ability of digital breast tomosynthesis(DBT) to display simulated lesions of the breast by using ACR-156 Model

目的以ACR-156模型评价数字乳腺断层融合X线成像(DBT)对乳腺模拟病灶的显示能力。方法选用不同数量的有机玻璃衰减板和ACR-156模型组合模拟不同等效乳腺压迫厚度(19mm、28mm、37mm、47mm、55mm和65mm)。采用Combo HD模式、在自动曝光控制下对模型进行摄影。根据美国放射学会(ACR)推荐的评分方法,三位评分者分别对ACR-156模型中的纤维条、微钙化点和肿块进行单独计分。结果 1)纤维条评分比较:DBT和全视野数字化乳腺摄影(FFDM)在每个压迫厚度中的评分比较,差异均无统计学意义(P>0.05);合成2D和FFDM在压迫厚度为19mm、28mm、37mm和47mm的评分比较,差异无统计学意义(P>0.05);在压迫厚度为55mm和65mm时,合成2D的评分均低于FFDM的评分,差异有统计学意义(P<0.05);2)微钙化点评分比较:DBT和FFDM在每个压迫厚度中的微钙化点评分比较,差异均无统计学意义(P>0.05);合成2D和FFDM在压迫厚度为19mm、28mm、37mm、47mm和55mm的评分比较,差异无统计学意义(P>0.05);压迫厚度为65mm时,合成2D的评分低于FFDM的评分,差异有统计学意义(P<0.05);3)肿块评分比较:压迫厚度为19mm和28mm时,DBT的评分高于FFDM和合成2D的评分,差异有统计学意义(P<0.05);压迫厚度为37mm、47mm和55mm时,DBT、FFDM和合成2D的评分一致;压迫厚度为65mm时,DBT和FFDM的评分均高于合成2D的评分,差异有统计学意义(P<0.05)。结论自动曝光控制下:1)压迫厚度小时,DBT显示肿块的能力优于FFDM;随着压迫厚度增大,DBT显示肿块的能力与FFDM相仿;2)各压迫厚度下DBT显示纤维条和微钙化点的能力与FFDM相仿;3)压迫厚度小时,合成2D显示纤维条、微钙化点和肿块的能力与FFDM相仿,随着压迫厚度增大,合成2D显示纤维条、微钙化点和肿块的能力均不如FFDM。

Objective To evaluate the ability of digital breast tomosynthesis to display simulated lesions of the breast by using ACR-156 Model. Methods Different quantities of organic glass attenuation boards and ACR-156 model are selected to simulate the different equivalent thicknesses of breast oppression （19 mm, 28 mm, 37 mm, 47 mm, 55 mm and 65 mm）. Combo HD model is adopted to shoot this model under the condition of automatic exposure control. According to the scoring method recom- mended by ACR, three evaluators score the fiber ribbon, micro-calcification and lump of ACR-156 model respectively. Results 1 ） Score comparison of fiber ribbon ： Through comparing the scores of DBT and full-field digital mammagraphy with different op- pression thicknesses, it is concluded that the difference has no statistical meaning （ P 〉 O. 05）. When oppression thickness e- quals to 19 mm, 28 mm, 37 mm or 47 mm, there is no statistical meaning （ P 〉 O. 05 ） as to the difference between composite 2D and FFDM. When oppression thickness equals to 55 mm or 65 mm, the score of composite 2D is lower than the score of FFDM, thus it has statistical meaning （ P 〈 O. 05） ; 2） Score comparison of micro-calcification： Through comparing the scores of micro- calcification of DBT and FFDM with＇ different oppression thicknesses, it is concluded that the difference has no statistical meaning （ P 〉 0.05 ）. When oppression thickness equals to 19 mm, 28 ram, 37 mm, 47 mm or 55 mm, there is no statistical meaning （ P 〉 0.05） as to the difference between composite 2D and FFDM. When oppression thickness equals to 65mm, the score of composite 2D is lower than the score of FFDM, thus it has statistical meaning （ P 〈0.05） ; 3） Score comparison of lump： When op- pression thickness equals to 19 mm or 28 mm, the score of DBT is higher than the scores of FFDM and composite 2D respectively, thus this difference is statistically meaningful （ P 〈 0.05 ）. When oppression thickness equals to 37 mm, 47 mm or 55 mm, DBT, FFDM and composite 2D have the same score. When oppression thickness equals to 65mm, the scores of DBT and FFDM are respectively higher than the score of composite 2D, thus this difference is statistically meaningful （ P 〈 O. 05）. Conclusion Under ACE control ： 1 ） When the oppression thickness is relatively small, the ability of DBT to display lump is superior to the a- bility of FFDM. As the oppression thickness increases, the ability of DBT to display lump is equivalent to the ability of FFDM ; 2） The ability of DBT to display fiber ribbon and micro-calcification is similar to the ability of FFDM ; 3） When the oppression thick- ness is relatively small, the ability of composite 2D to display fiber ribbon, micro-calcification and lump is similar to the ability of FFDM. As the oppression thickness increases, the ability of composite 2D to display fiber ribbon, micro-calcification and lump becomes is inferior to the ability of FFDM.