本文關(guān)鍵詞： CTA 主動(dòng)脈 低劑量 體重指數(shù)　出處：《吉林大學(xué)》2012年碩士論文　論文類型：學(xué)位論文

【摘要】：目的： 第一部分：比較120kV自動(dòng)管電流組、80kV490mAs掃描組，兩組之間主動(dòng)脈CTA圖像質(zhì)量與射線劑量的變化，并比較80kV管電壓下不同體重指數(shù)的患者CT輻射計(jì)量與圖像質(zhì)量的變化，為受檢者提供個(gè)體化掃描方案。 方法： 搜集在我院接受256層螺旋CT主動(dòng)脈造影檢查的患者146例，實(shí)驗(yàn)分成兩部分，第一部分設(shè)置管電壓為120kV（120kV掃描組）自動(dòng)管電流，80kV管電壓（80kV掃描組）490mAs管電流，第二部分設(shè)置特定管電壓為80KV，根據(jù)體重指數(shù)分成3組，A組，體重指數(shù)大于25kg/m~2的患者；B組，體重指數(shù)在20-25kg/m~2之間；C組，體重指數(shù)在20kg/m~2以內(nèi)。其中A組給予490mAs管電流（490mAs掃描組），B組給予400mAs管電流（400mAs掃描組），C組給予300mAs管電流（300mAs掃描組）。 結(jié)果： 80kV掃描組主動(dòng)脈強(qiáng)化值較120kV掃描組主動(dòng)脈強(qiáng)化值高，但無(wú)統(tǒng)計(jì)學(xué)意義，(372.1±74.7HU vs368.9±78.8HU; P=0.87)。80kV掃描組及120kV掃描組圖像SNR分別為（34.3±9.0）和（36.3±9.1），差異無(wú)統(tǒng)計(jì)學(xué)意義(P=0.39)，對(duì)比度噪聲比分別為（29.0±8.6）和（30.7±8.3），差異無(wú)統(tǒng)計(jì)學(xué)意義(P=0.44）。80kV掃描組和120kV掃描組的有效劑量分別為（9.7±0.8）mSv和（14.3±5.9）mSv，差異有統(tǒng)計(jì)學(xué)意義(P0.001）。490mAs掃描組、400mAs掃描組及300mAs掃描組信號(hào)噪聲比(SNR)和對(duì)比度噪聲比(CNR)，P值分別為0.687和0.749，均無(wú)統(tǒng)計(jì)學(xué)意義。490mAs掃描組ED為（9.939±0.4280）mSv，400mAs掃描組ED為（7.794±0.5765）mSv，300mAs掃描組ED為（5.836±0.3663）mSv，三者有顯著性差異（P=0.000）。對(duì)三組進(jìn)行兩兩比較P值均小于0.05，，均有統(tǒng)計(jì)學(xué)意義。 結(jié)論： 在CT主動(dòng)脈造影中，80kV管電壓所得到的圖像信號(hào)噪聲比和對(duì)比度噪聲比及圖像質(zhì)量與120kV管電流相比沒(méi)有顯著變化。80kV管電壓在多層螺旋CT主動(dòng)脈造影中即可得到符合診斷條件的圖像質(zhì)量。在此管電壓基礎(chǔ)上對(duì)于體重指數(shù)在20～25kg/m~2之間，應(yīng)選用400mAs管電流，體重指數(shù)小于20kg/m~2應(yīng)選用300mAs管電流。降低管電流，直接降低了光子能量，但增加了造影劑的CT值。在以后的研究中，我們還可以根據(jù)患者的體重指數(shù)，在降低輻射劑量的同時(shí)，降低造影劑的使用量，既降低了患者的輻射危害又緩解了患者的經(jīng)濟(jì)壓力。
[Abstract]:Objective: The first part: compare the quality of aortic CTA image and the change of radiation dose between the 120 kV automatic tube current group and the 80kV 490mAs scanning group. The changes of CT radiation measurement and image quality of patients with different body mass index (BMI) under 80 kV tube voltage were compared. Methods: 146 patients underwent 256-slice spiral CT aortic angiography in our hospital were divided into two parts. In the first part, the voltage of the tube was 120 kV / 120 kV) automatic tube current was set. The voltage of 80kV tube was divided into three groups according to body mass index (BMI). The voltage of 80kV scanning group was 490mAs current. The second part was divided into three groups according to body mass index (BMI) with a specific voltage of 80kV. Patients with body mass index greater than 25kg / mm2; In group B, body mass index ranged from 20 to 25 kg / m ~ (2); In group C, body mass index was less than 20 kg 路m ~ (-2). Group A was given 490mAs current current scan group. Group B was given 400mAs current and 400mAs scanning group was given 300mAs current and 300mAs scanning group. Results: The enhancement value of aorta in 80 kV scan group was higher than that in 120 kV scan group, but there was no significant difference between them (372.1 鹵74.7 Hu vs368.9 鹵78.8 HUU). The SNR of 0.870.80kV scanning group and 120kV scanning group were 34.3 鹵9.0) and 36.3 鹵9.1) respectively. The contrast noise ratio was 29.0 鹵8.6) and 30.7 鹵8.3 respectively. There was no significant difference in the effective doses of 0.440.80kV scanning group and 120kV scanning group (9.7 鹵0.8mSv and 14.3 鹵5.9 mSv, respectively). The difference was statistically significant (P 0.001N. 490mAs scan group, 400mAs scan group and 300mAs scan group, signal noise ratio (SNR) and contrast noise ratio (CNR)). P values were 0.687 and 0.749, respectively. Ed in 490mAs group was 9.939 鹵0.4280mSv. Ed of 400mAs scan group was 7.794 鹵0.5765mSvA300mAs scan group, Ed was 5.836 鹵0.3663mSv. There was significant difference among the three groups (P < 0.05, P < 0.05). Conclusion: In CT aortic angiography. The image signal noise ratio, contrast noise ratio and image quality obtained from 80 kV tube voltage have no significant change compared with 120 kV current. 80 kV tube voltage can be obtained in multislice spiral CT aortic angiography. The image quality was obtained according to the diagnostic conditions. Based on the voltage of the tube, the body mass index was between 20 and 25 kg / mm2. We should choose 400mAs current and 300mAs current when the body mass index is less than 20kgmm2, which reduces the photon energy directly. However, the CT value of contrast agent was increased. In future studies, we can also reduce the dose of contrast agent while reducing the dose of radiation according to the patient's body mass index. Both reduce the patient's radiation hazards and ease the patient's economic pressure.
【學(xué)位授予單位】：吉林大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2012
【分類號(hào)】：R816.2

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