【摘要】：第一部分水模實(shí)驗(yàn)?zāi)康?檢測(cè)三維自適應(yīng)迭代劑量降低(Adaptive Iterative Dose Reduction 3D,AIDR 3D)算法的降噪能力。評(píng)估不同管電壓對(duì)圖像噪聲的影響程度。材料和方法:采用普通水模(直徑25cm),按照120KV,濾波反投影(Filtered Back Projection,FBP)重建;120KV,AIDR 3D重建;100KV,AIDR 3D重建;80KV,AIDR 3D重建四組掃描方案,以不同的噪聲指數(shù)(Noise Index,NI)(NI 5-11,間隔0.5)對(duì)水模進(jìn)行掃描,測(cè)量四組圖像的噪聲,測(cè)算AIDR 3D的降噪能力。結(jié)果:采用120KV+AIDR 3D重建算法圖像噪聲比120KV+FBP重建圖像噪聲降低,兩者間具有統(tǒng)計(jì)學(xué)差異(q=7.131,P0.001);100KV+AIDR 3D重建算法圖像噪聲比120KV+FBP重建算法圖像噪聲降低,兩者間具有統(tǒng)計(jì)學(xué)意義(q=6.064,P0.001);80KV+AIDR 3D重建算法比100KV+AIDR 3D重建算法圖像噪聲增加,兩者間具有統(tǒng)計(jì)學(xué)差異(q=3.888,P0.05)。結(jié)論:①與FBP算法相比,AIDR 3D重建算法能明顯降低圖像噪聲。②管電壓為80KV時(shí)圖像噪聲較100KV及120KV時(shí)明顯增高。第二部分臨床實(shí)驗(yàn)?zāi)康?探討自動(dòng)管電流調(diào)節(jié)技術(shù)和低管電壓結(jié)合自動(dòng)管電流調(diào)節(jié)技術(shù)聯(lián)合三維自適應(yīng)迭代劑量降低(Adaptive Iterative Dose Reduction 3D,AIDR 3D)算法在低對(duì)比劑劑量肝臟增強(qiáng)CT中的應(yīng)用價(jià)值。材料和方法:前瞻性的將150例行常規(guī)肝臟增強(qiáng)CT的患者按隨機(jī)表分為3組(A,B,C),每組50例,A組為常規(guī)組,采用FBP重建+常規(guī)對(duì)比劑用量(1.5ml/Kg),B組及C組為雙低組,二者管電壓不同,其中B組為120KV,C組為100KV,均采用AIDR 3D重建+低對(duì)比劑用量(1.0ml/Kg)。記錄每組圖像的CT容積劑量指數(shù)(CT Dose index-volume,CTDI vol)、劑量長(zhǎng)度乘積(Dose Length Product,DLP),并計(jì)算出3組的有效劑量(Effective Dose,ED),平均CT值、圖像噪聲、信噪比(SNR)、對(duì)比信噪比(CNR)。對(duì)3組圖像的診斷信息(圖像主觀噪聲、圖像總體質(zhì)量)按1-4分(1分最差,4分最優(yōu))予以評(píng)分。計(jì)量資料采用完全隨機(jī)設(shè)計(jì)的方差分析及秩和檢驗(yàn)。計(jì)數(shù)資料采用完全隨機(jī)設(shè)計(jì)的非參數(shù)檢驗(yàn)(Kruskal-Wallis)對(duì)結(jié)果進(jìn)行比較。結(jié)果:雙低組(B組及C組)的有效劑量較常規(guī)組(A組)減低(A、B、C組分別為2.98±1.33,2.23±0.75,2.54±0.55),A組與B組間差異具有統(tǒng)計(jì)學(xué)差異(F=8.10,t=4.004,P=0.000,0.01),A組與C組間差異亦具有統(tǒng)計(jì)學(xué)意義(F=8.10,t=2.348,P=0.020,0.05);B組和C組之間差異無(wú)統(tǒng)計(jì)學(xué)意義(p0.05)。圖像質(zhì)量客觀評(píng)估中,A組圖像肝實(shí)質(zhì)、主動(dòng)脈及門(mén)靜脈噪聲最高,C組最低,三組之間差異具有統(tǒng)計(jì)學(xué)意義(肝實(shí)質(zhì):F=216.06,主動(dòng)脈:F=150.83,門(mén)靜脈:F=150.61;P均等于0.000,0.01)。A組與C組圖像肝實(shí)質(zhì)、主動(dòng)脈及門(mén)靜脈CT值無(wú)統(tǒng)計(jì)學(xué)差異(p0.05),B組最低,與A組和C組間有統(tǒng)計(jì)學(xué)差異(肝實(shí)質(zhì):F=38.79,主動(dòng)脈:F=52.78,門(mén)靜脈:F=56.19,P均等于0.000,P0.01)。B組的CNR與A組相比,無(wú)統(tǒng)計(jì)學(xué)差異(p0.05);C組的CNR高于A組和B組(A組VS C組:F=37.62,t=7.010,P=0.000,0.01;B組VS C組:F=37.62,t=7.937,P=0.000,0.01)。C組的SNR最高,A組最低,三組間差異具有統(tǒng)計(jì)學(xué)意義(A組VS B組:F=162.36,t=3.096,P=0.000,0.01;A組VS C組:F=162.36,t=16.936,P=0.000,0.01;B組VS C組:F=162.36,t=13.84,P=0.000,0.01)。主觀評(píng)估中,B組和C組的圖像質(zhì)量評(píng)分均高于A組,存在顯著統(tǒng)計(jì)學(xué)差異(A組VS B組:H=-5.288,P=0.000,0.01;A組VS C組:H=-5.688,P=0.000,0.01)。C組的圖像質(zhì)量評(píng)分高于B組,差異無(wú)統(tǒng)計(jì)學(xué)意義(P0.05)。結(jié)論:①AIDR 3D重建結(jié)合低對(duì)比劑用量較FBP重建結(jié)合常規(guī)對(duì)比劑用量在腹部CT增強(qiáng)中能得到相當(dāng)甚至更好的圖像質(zhì)量;②低管電壓聯(lián)合自動(dòng)管電流調(diào)節(jié)技術(shù)較單純自動(dòng)管電流調(diào)節(jié)在肝臟低對(duì)比劑用量增強(qiáng)CT中能得到更好的圖像質(zhì)量。
[Abstract]:The first part of the water model experiment is to test the noise reduction ability of the adaptive Iterative Dose Reduction 3D (AIDR 3D) algorithm and evaluate the influence of different tube voltages on image noise. Build; 120KV, AIDR 3D reconstruction; 100KV, AIDR 3D reconstruction; 80KV, AIDR 3D reconstruction four groups of scanning scheme, with different noise index (NI) (NI 5-11, interval 0.5) to scan the water model, measure the noise of the four groups of images, calculate the noise reduction ability of AIDR 3D. Results: 120KV + AIDR 3D reconstruction algorithm image noise ratio 120KV + FBP reconstruction image noise reconstruction. The image noise of 100KV+AIDR 3D reconstruction algorithm was lower than that of 120KV+FBP reconstruction algorithm (q=6.064, P 0.001), and that of 80KV+AIDR 3D reconstruction algorithm was higher than that of 100KV+AIDR 3D reconstruction algorithm (q=3.888, P 0.05). Conclusion: Compared with FBP algorithm, AIDR 3D reconstruction algorithm can significantly reduce image noise. 2) The image noise at 80 KV tube voltage is significantly higher than that at 100 KV and 120 KV tube voltage. Materials and Methods: 150 patients with routine hepatic contrast-enhanced CT were prospectively divided into three groups (A, B, C) according to the randomized table, 50 cases in each group, 50 cases in group A, FBP reconstruction + routine contrast medium dosage (1.5ml/Kg), and two low groups in group B and C. The CT Dose Index-volume (CTDI vol), Dose Length Product (DLP) and effective dose (ED), mean CT value, image noise were recorded for each group. The diagnostic information (subjective noise, overall image quality) of the three groups of images was scored by 1-4 points (the worst one, the best four). The measurement data were analyzed by variance analysis and rank sum test. The counting data were analyzed by Kruskal-Wallis. Results: The effective dose of double-low group (group B and group C) was lower than that of group A (group A, group B and group C were 2.98 [1.33, 2.23] 0.75, 2.54 [0.55] respectively). There were significant differences between group A and group B (F = 8.10, t = 4.004, P = 0.000, 0.01). There were also significant differences between group A and group C (F = 8.10, t = 2.348, P = 0.020, 0.05). In the objective evaluation of image quality, the liver parenchyma, aorta and portal vein noise were the highest in group A, and the lowest in group C. There were significant differences among the three groups (liver parenchyma: F = 216.06, aorta: F = 150.83, portal vein: F = 150.61; P = 0.000, 0.01). There was no unified CT value between group A and group C. The difference was statistically significant (p0.05), the lowest in group B, and the lowest in group A and C (liver parenchy: F = 38.79, ao: F = 52.78, portal ve: F = 56.19, P = 56.19, P = 0.000, P = 0.01). There was no significant difference in CNR between group B and group A (p0.05); the CNR in group C was higher in group C than group A and group B (VC group A: F = 37.62, t = 37.62, t = 7.62, t = 7.010, t = 7.010.01, P = 0.01; VC group B: F = 37.62, F = 37.62, P = 37.62, P = 7.62, t = 7.62, t = 7.937, t In the meantime, it is necessary to study the relationship between the two. The SNR of group C was the highest, and that of group A was the lowest (group A vs group B: F = 162.36, t = 3.096, P = 0.000, 0.01); group A vs group C: F = 162.36, t = 16.936, P = 0.000, 0.01; group B vs group B: F = 162.36, t = 13.84, P = 0.000, 0.01). Group H = - 5.288, P = 0.000, 0.01; Group A: VS C: H = - 5.688, P = 0.000, 0.01). The image quality score of group C was higher than that of group B, and there was no significant difference (P 0.05). Conclusion: The image quality of AIDR 3D reconstruction combined with low contrast agent dosage was better than that of FBP reconstruction combined with conventional contrast agent dosage in abdominal CT enhancement. Automated tube current regulation technique can obtain better image quality than auto tube current regulation in contrast enhanced CT with low dose of contrast medium.
【學(xué)位授予單位】：蘇州大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：R816.5

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