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Objective To characterize the feasibility of low-dose CT angingraphy on 16-slice multislice computed tomography (16-MSCT), and its relationship to the noise in the pre-contrast image and enhancement value.Methods Forty-three consecutive patients (male 21, female 22, mean age 59 years, median age 56 years) underwent abdominal 16-MSCT (Toshiba Aquilion 16) with constant scanning parameters including 120 kVp, a 0.5-second gantry rotation time, a pitch of 0.938: 1, and 16×1-mm detector collimation.The mA was set at 200 in the pre-contrast scan and 160 in the contrast-enhanced scan.The arterial phase images were retrospectively reconstructed with 1-mm slice thickness, 0.8 mm interval.The pre-contrast noise was defined as the standard deviation (SD) of the aorta at the level of right posterior crura of diaphragm.The enhancement of aorta was also measured at level of celiac artery.The volume rendering of CT angiography was made and classified into three grades (excellent, good, bad).Receiver operating characteristic curve (ROC) was used to evaluate the relationship between the image quality of CT angiography and noise in the pre-contrast image and enhancement value.Results Twenty-five cases had the aorta enhancement between 300.0--400.0 HU.The sensitivity and specificity of excellent CTA image was 75% and 62%, respectively when the SD was 12.00.Eighteen cases had the aorta enhancement more than 400.0 HU.The sensitivity and specificity of excellent CTA image was all 100% when the SD was 12.25, and 100% and 75%, respectively when the SD was 13.35.The area under curve of CTA image quality and enhancement in receiver-operated characteristic analysis was O.907.The enhancement was more than 356.7 HU when the sensitivity and specificity of excellent CTA image was 100% and 60%, respectively, and 389.8 HU when 78% and 80%.When the enhancement was more than 442.4 HU, the specificity of excellent CTA image was 100%.Conclusions MSCT angiography with low radiation dose is feasible.Good CT angiography demands great enhancement, and then, the needed mAs is lower when the SD is smaller. 相似文献
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胃肠道间质瘤的CT诊断价值 总被引:14,自引:0,他引:14
目的分析胃肠道间质瘤(GIST)的CT表现特点,探讨CT对该肿瘤的诊断价值。方法回顾性分析经手术病理证实的GIST32例,术前均行CT平扫和增强扫描,15例行胃肠道气钡双重造影检查。结果肿瘤发生于胃18例,空肠4例,回肠3例,食管和肠系膜各2例,升结肠、直肠和大网膜各1例。32例CIST中,良性12例,肿瘤直径≤5.0cm,边界清楚,密度均匀;恶性20例,肿块直径≥7cm,肿瘤边缘有分叶,肿块内有坏死,肿瘤的溃疡大而深,周围组织侵犯或远处转移。本组CT定位准确度为96.9%(31/32),CT判断恶性准确度为93.8%(30/32)。结论CT对GIST具有较高的诊断价值,可弥补X线钡餐造影的局限性,对临床早期诊断和治疗以及评价预后具有重要价值。 相似文献
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目的:探讨MSCT对肠石性肠梗阻的临床应用价值。方法:对23例经手术或临床诊断证实的肠石性肠梗阻的MSCT及多平面重组(MPR)资料进行回顾性分析,着重于定性与定位诊断、并发症与合并症的显示,并与手术所见对照。结果:15例经手术证实的病例定位诊断均正确;21例(21/23)定性诊断正确,"气泡征"(22/23)与"瓶塞征"(21/23)为肠石性肠梗阻的最典型CT表现,1例对合并症的定性诊断不确定,1例遗漏合并症;2例显示肠穿孔。结论:MSCT结合MPR对肠石性肠梗阻的定位定性诊断、对其并发症及合并症的显示具有重要的临床应用价值。 相似文献
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目的 探讨16层CT进行低剂量CTA的可行性,以及与平扫噪声和增强值的关系.方法 选取连续上腹部增强检查中,动脉期主动脉增强CT值300.0 HU以上的43例患者,采用16层CT扫描,回顾性动脉期重建和标准算法.在平扫图像上选择右侧后膈脚水平图像测定腹主动脉腔的CT值,CT值的标准差(SD)定义为图像噪声;增强图像上测定腹腔动脉根部水平的主动脉CT值.动脉期数据进行VR后处理,其图像评价分优、良、差,并以此为标准进行图像质量与主动脉增强值和平扫SD值之间关系的受试者操作特性曲线(ROC)分析.结果 增强主动脉CT值在300.0~400.0 HU之间共25例,SD=12.00时,图像为优的敏感性75%,特异性62%.主动脉CT值在400.0 HU以上共18例,SD=12.25时,图像为优的敏感性和特异性均为100%;SD=13.35时,图像为优的敏感性100%,特异性75%.按主动脉强化值与CTA VR图像质量相关性分析,ROC曲线下面积0.907,图像为优的敏感性100%、特异性60%时的强化值阈值为356.7 HU;敏感性78%、特异性80%时的强化值阈值为389.8 HU;特异性100%时的最低强化值为442.4 HU,此时敏感性56%.结论 低剂量CTA切实可行,保证良好成像效果的前提下,平扫SD值越小,使用的mAs就越小;而成像效果越好,则可以使用的mAs值也可以减小. 相似文献
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Objective To characterize the feasibility of low-dose CT angingraphy on 16-slice multislice computed tomography (16-MSCT), and its relationship to the noise in the pre-contrast image and enhancement value.Methods Forty-three consecutive patients (male 21, female 22, mean age 59 years, median age 56 years) underwent abdominal 16-MSCT (Toshiba Aquilion 16) with constant scanning parameters including 120 kVp, a 0.5-second gantry rotation time, a pitch of 0.938: 1, and 16×1-mm detector collimation.The mA was set at 200 in the pre-contrast scan and 160 in the contrast-enhanced scan.The arterial phase images were retrospectively reconstructed with 1-mm slice thickness, 0.8 mm interval.The pre-contrast noise was defined as the standard deviation (SD) of the aorta at the level of right posterior crura of diaphragm.The enhancement of aorta was also measured at level of celiac artery.The volume rendering of CT angiography was made and classified into three grades (excellent, good, bad).Receiver operating characteristic curve (ROC) was used to evaluate the relationship between the image quality of CT angiography and noise in the pre-contrast image and enhancement value.Results Twenty-five cases had the aorta enhancement between 300.0--400.0 HU.The sensitivity and specificity of excellent CTA image was 75% and 62%, respectively when the SD was 12.00.Eighteen cases had the aorta enhancement more than 400.0 HU.The sensitivity and specificity of excellent CTA image was all 100% when the SD was 12.25, and 100% and 75%, respectively when the SD was 13.35.The area under curve of CTA image quality and enhancement in receiver-operated characteristic analysis was O.907.The enhancement was more than 356.7 HU when the sensitivity and specificity of excellent CTA image was 100% and 60%, respectively, and 389.8 HU when 78% and 80%.When the enhancement was more than 442.4 HU, the specificity of excellent CTA image was 100%.Conclusions MSCT angiography with low radiation dose is feasible.Good CT angiography demands great enhancement, and then, the needed mAs is lower when the SD is smaller. 相似文献
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Objective To characterize the feasibility of low-dose CT angingraphy on 16-slice multislice computed tomography (16-MSCT), and its relationship to the noise in the pre-contrast image and enhancement value.Methods Forty-three consecutive patients (male 21, female 22, mean age 59 years, median age 56 years) underwent abdominal 16-MSCT (Toshiba Aquilion 16) with constant scanning parameters including 120 kVp, a 0.5-second gantry rotation time, a pitch of 0.938: 1, and 16×1-mm detector collimation.The mA was set at 200 in the pre-contrast scan and 160 in the contrast-enhanced scan.The arterial phase images were retrospectively reconstructed with 1-mm slice thickness, 0.8 mm interval.The pre-contrast noise was defined as the standard deviation (SD) of the aorta at the level of right posterior crura of diaphragm.The enhancement of aorta was also measured at level of celiac artery.The volume rendering of CT angiography was made and classified into three grades (excellent, good, bad).Receiver operating characteristic curve (ROC) was used to evaluate the relationship between the image quality of CT angiography and noise in the pre-contrast image and enhancement value.Results Twenty-five cases had the aorta enhancement between 300.0--400.0 HU.The sensitivity and specificity of excellent CTA image was 75% and 62%, respectively when the SD was 12.00.Eighteen cases had the aorta enhancement more than 400.0 HU.The sensitivity and specificity of excellent CTA image was all 100% when the SD was 12.25, and 100% and 75%, respectively when the SD was 13.35.The area under curve of CTA image quality and enhancement in receiver-operated characteristic analysis was O.907.The enhancement was more than 356.7 HU when the sensitivity and specificity of excellent CTA image was 100% and 60%, respectively, and 389.8 HU when 78% and 80%.When the enhancement was more than 442.4 HU, the specificity of excellent CTA image was 100%.Conclusions MSCT angiography with low radiation dose is feasible.Good CT angiography demands great enhancement, and then, the needed mAs is lower when the SD is smaller. 相似文献
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Objective To characterize the feasibility of low-dose CT angingraphy on 16-slice multislice computed tomography (16-MSCT), and its relationship to the noise in the pre-contrast image and enhancement value.Methods Forty-three consecutive patients (male 21, female 22, mean age 59 years, median age 56 years) underwent abdominal 16-MSCT (Toshiba Aquilion 16) with constant scanning parameters including 120 kVp, a 0.5-second gantry rotation time, a pitch of 0.938: 1, and 16×1-mm detector collimation.The mA was set at 200 in the pre-contrast scan and 160 in the contrast-enhanced scan.The arterial phase images were retrospectively reconstructed with 1-mm slice thickness, 0.8 mm interval.The pre-contrast noise was defined as the standard deviation (SD) of the aorta at the level of right posterior crura of diaphragm.The enhancement of aorta was also measured at level of celiac artery.The volume rendering of CT angiography was made and classified into three grades (excellent, good, bad).Receiver operating characteristic curve (ROC) was used to evaluate the relationship between the image quality of CT angiography and noise in the pre-contrast image and enhancement value.Results Twenty-five cases had the aorta enhancement between 300.0--400.0 HU.The sensitivity and specificity of excellent CTA image was 75% and 62%, respectively when the SD was 12.00.Eighteen cases had the aorta enhancement more than 400.0 HU.The sensitivity and specificity of excellent CTA image was all 100% when the SD was 12.25, and 100% and 75%, respectively when the SD was 13.35.The area under curve of CTA image quality and enhancement in receiver-operated characteristic analysis was O.907.The enhancement was more than 356.7 HU when the sensitivity and specificity of excellent CTA image was 100% and 60%, respectively, and 389.8 HU when 78% and 80%.When the enhancement was more than 442.4 HU, the specificity of excellent CTA image was 100%.Conclusions MSCT angiography with low radiation dose is feasible.Good CT angiography demands great enhancement, and then, the needed mAs is lower when the SD is smaller. 相似文献