本文關(guān)鍵詞：CT能譜成像在孤立性肺結(jié)節(jié)診斷中的應(yīng)用，，由筆耕文化傳播整理發(fā)布。

        目的：通過對孤立性肺結(jié)節(jié)進(jìn)行能譜成像(Gemstone Spectral Imaging, GSI)掃描,探討能譜成像在肺結(jié)節(jié)鑒別診斷中的價值。材料與方法：1能譜CT對肺結(jié)節(jié)模型CT值測量的研究用直徑不同的球體模擬肺結(jié)節(jié)(直徑分別為20.0、10.0、5.0mm)；每種直徑的結(jié)節(jié)分別由3種密度不同的物質(zhì)制成(聚丙烯、尼龍、腈綸),相應(yīng)CT值分別為-100HU、60HU、100HU。結(jié)節(jié)固定在塑料肺基底模型(-900HU)內(nèi),周圍加基液或基液加動物骨骼以改變模型外周環(huán)境。Discovery CT750HD能譜CT對肺結(jié)節(jié)模型進(jìn)行GSI掃描和常規(guī)掃描(混合能量)。GSI掃描參數(shù)：140kVp/80kVp瞬時切換；630mA;層厚64×0.625mm；螺距0.516：1；SFOV50cm;DFOV38cm。常規(guī)掃描管電壓120kVp,管電流(mA)根據(jù)GS工掃描患者的CT劑量指數(shù)確定,其他掃描參數(shù)與GSI掃描一致。對兩種不同外周環(huán)境中的模型分別用三種不同的轉(zhuǎn)速(0.5s/r,0.8s/r,1.0s/r),即掃描時間分別為(0.5s,0.8s,1.0s)進(jìn)行掃描。1.1三位經(jīng)驗(yàn)豐富的影像學(xué)醫(yī)師獨(dú)立測量不同掃描條件下直徑為20mm結(jié)節(jié)的CT值及SD值�；旌夏芰亢蛦文軛l件下所得結(jié)節(jié)的CT值及相應(yīng)的圖像信噪比SNR進(jìn)行比較。1.2應(yīng)用能譜圖像分析軟件GSI-Viewer對所有結(jié)節(jié)的單能量圖像進(jìn)行數(shù)據(jù)測量及分析,得出相應(yīng)的最佳CNR曲線。三位經(jīng)驗(yàn)豐富的影像學(xué)醫(yī)師獨(dú)立測量并記錄每個結(jié)節(jié)的最高CNR的keV單能量,測量3次,取其平均值。最佳CNR的KeV條件下測量直徑為20mm的結(jié)節(jié)模型CT值與73KeV及實(shí)際值比較分析。1.3在最佳CNR KeV單能圖像上對所有肺結(jié)節(jié)模型單能量圖像進(jìn)行數(shù)據(jù)測量及分析,得出相應(yīng)的能譜曲線。反映CT值衰減的CT能譜曲線的差異可以用曲線斜率來定量評估,分析其與結(jié)節(jié)的密度、直徑、掃描時間、外周環(huán)境的線性相關(guān)性。2.能譜CT對肺結(jié)節(jié)患者掃描Discovery CT750HD能譜CT對42例經(jīng)病理證實(shí)或隨訪的孤立性肺結(jié)節(jié)患者進(jìn)行GSI掃描。掃描參數(shù)：140kVp/80kVp瞬時切換；630mA；層厚64×0.625mm；螺距0.516:1;SFOV50cm；DFOV38cm；轉(zhuǎn)速0.8s/r。其中鱗癌17例,腺癌15例,肺炎10例。應(yīng)用能譜圖像分析軟件GSI-Viewer對單能量圖像進(jìn)行分析,得出能譜曲線,分析不同病理類型的肺結(jié)節(jié)能譜曲線的差異性。結(jié)果：1能譜CT對肺結(jié)節(jié)模型掃描1.1(1)分別在基液與基液+骨骼條件下對肺結(jié)節(jié)模型進(jìn)行GSI掃描：所得CT值均無明顯統(tǒng)計(jì)學(xué)差異(P>0.05)。所有結(jié)節(jié)轉(zhuǎn)速為0.8s/r及60Hu結(jié)節(jié)轉(zhuǎn)速為1.0s/r時SNR無明顯統(tǒng)計(jì)學(xué)差異(P>0.05)；其他條件下SNR間差別有統(tǒng)計(jì)學(xué)意義(P<0.05)。(2)分別在基液與基液+骨骼條件下對肺結(jié)節(jié)模型進(jìn)行常規(guī)掃描：所得CT值間差別均有統(tǒng)計(jì)學(xué)意義(P<0.05)。所有SNR間差別亦有統(tǒng)計(jì)學(xué)意義(P<0.05)。1.2(1)所有結(jié)節(jié)模型所測得最佳CNR符合正態(tài)分布,其95%可信區(qū)間為(64.75-65.27),則在均值65keV時,能獲得最高的CNR。(2)65keV.73keV時測得直徑為20mm結(jié)節(jié)的CT值與實(shí)際CT值的差異及65keV與73keV之間差異均有統(tǒng)計(jì)學(xué)意義(P<0.05)。GSI掃描73keV條件下-100HU、60HU、100HU結(jié)節(jié)模型CT值分別為-133.95±0.60、23.47±1.04、89.33±1.38；65keV條件下CT值分別為-119.51±2.43、40.39±1.43、102.63±1.88。即73keV比65keV時測得結(jié)節(jié)CT值的平均值均更接近于實(shí)際的CT值。1.3肺結(jié)節(jié)的密度、直徑、掃描時間、外周環(huán)境作為自變量,能譜曲線CT值衰減率作為因變量建立一個多元回歸線性模型。結(jié)果顯示：“能譜曲線CT值的衰減率”與“結(jié)節(jié)密度”、“結(jié)節(jié)直徑”呈正相關(guān)；“結(jié)節(jié)密度”與“能譜曲線CT值的衰減率”均比“結(jié)節(jié)直徑”與“能譜曲線CT值的衰減率”具有更強(qiáng)的線性相關(guān)性。2能譜CT對孤立性肺結(jié)節(jié)患者掃描對鱗癌、腺癌、肺炎的能譜曲線CT值衰減率的比較方差分析結(jié)果示：F=167.727,P=0.000<0.005,處理因素的3組水平中至少有一組的總體平均值不同于其他各組。鱗癌、腺癌、肺炎兩兩比較,P均<0.005,可以認(rèn)為鱗癌組與腺癌組、鱗癌組與肺炎組、腺癌組與肺炎組的能譜曲線CT值的衰減率不等,差異有明顯統(tǒng)計(jì)學(xué)意義。結(jié)論：GSI掃描可有效減除射束硬化偽影對CT值的影響得到較常規(guī)掃描更準(zhǔn)確的肺結(jié)節(jié)CT值,肺結(jié)節(jié)模型在65keV的單能水平下得到最高CNR。CNR。盡管73keV條件下GSI掃描測得的CT值與實(shí)際CT值間有一定差異,但較65keV條件下CT值更準(zhǔn)確。肺結(jié)節(jié)能譜曲線CT值的衰減率與結(jié)節(jié)密度、結(jié)節(jié)直徑呈正相關(guān),結(jié)節(jié)密度相關(guān)性更大。即不同密度、不同直徑的結(jié)節(jié),其能譜曲線CT值的衰減率有差異一定,不同密度結(jié)節(jié)之間差異大。不同病理類型的肺結(jié)節(jié)其能譜曲線CT值的衰減率有一定差異。

    ObjectiveTo evaluate the diagnosis of gemstone spectral imaging (GSI) of solitary pulmonary nodules with Discovery CT750HD.Methods1. A pulmonary nodule phantom imaging with Discovery CT750HD:The spherical pulmonary nodules made with three different kinds of materials (Polypropylene, Monomer casting nylon and ACRYLIC). Each material was applied to represent different density (-100HU,60HU and100HU). The diameters of nodes were20.0mm,10.0mm,5.0mm. All the nodules were set in a plastic lung phantom (-900HU). Phantom was fixed in a container filled with fluid, muscle and bone to simulate thorax. The phantom scan was performed under both single energy (SE) and mixed energy (ME) CT techniques. Scans were performed with Discovery CT750HD scanner using GSI (Gemstone Spectral Imaging) technique (GSIKV,630mA,64×0.625mm slices,0.516:1pitch,50cm scan field of view,38cm display field of view) with there different ratation time (0.5s,0.8s,1.0s). In addition, images were generated using the high resolution120kVp technique (convert mA according to GSI imaging CTDI, other parameters were the same with SECT). Scans were performed with and without the added bone.1.1Quantitative CT numbers and SD numbers measurement of nodules (diameters of nodes were20.0mm) at different scan conditions were done by three experienced radiologists on the workstation. CT numbers SNR of each nodule under different SECT and MECT were compared.1.2Using the spectral analysis software to acquire the best contrast-to-noise ratio (CNR) curves of all nodules. The homologous keV of of the best CNR measurement of nodules were done by three experienced radiologists on the workstation, repeated three times and took the averages. Comparing the CT numbers of the homologous keV of best CNR with the CT numbers of73keV, the diameter of nodes was20.0mm.1.3Using the spectral analysis software to acquire the spectrum curves of all nodules. The curves slope could evaluate the difference of spectrum curves. Analysising the Linear correlation between the curves slope and nodules density, nodules diameter, ratation time and added bone.2. Pulmonary nodule patients imaging with Discovery CT750HD:GSI of42pulmonary nodule patients (squamous carcinoma17, adenocarcinoma15, pneumonia10) confirmed by pathology or foliowup data. Scans were performed with Discovery CT750HD (GSIKV,630mA,64×0.625mm slices,0.516:1pitch,50cm scan field of view,38cm display field of view,0.8s ratation time). Analysising the differences of spectrum curves between different pulmonary nodules pathology.Results1. A pulmonary nodule phantom imaging with Discovery CT750HD:(1) The phantom scanned under SE in Nacl+Model or Nacl+Model+Bone with Discovery CT750HD:All the CT numbers didn’t show significant difference (P>0.05). In conditions of (0.8s, ratation time) and (1.0s, ratation time;60HU, density), the SNR didn’t show significant difference (P>0.05), the other conditions the SNR showed significant difference (P<0.05).(2) The phantom scanned under ME in Nacl+Model or Nacl+Model+Bone with Discovery CT750HD:All the CT numbers showed significant difference (P <0.05). All the SNR also showed significant difference (P<0.05).1.2(1) The CNR of pulmonary nodules met normal distribution. The confidence interval was (64.75-65.27).65keV image of pulmonary nodule and lung had the best CNR.(2) The CT numbers of65keV,73keV and standard CT numbers of nodules (diameters of nodes were20.0mm) show significant difference (P<0.05). The CT numbers of65keV and73keV also show significant difference (P<0.05). The CT numbers of-100HU,60HU,100HU were-133.95±0.60,23.47±1.04,89.33±1.38under73keV, and were-119.51±2.43,40.39±1.43,102.63±1.88under65keV. The CT numbers of73keV were more accurate.1.3Taking the nodules density, nodules diameter, ratation time, added bone as independent variable and taking the spectrum curves slope as dependent variable to acquire multiple regression linear model."The spectrum curves slope" was positively related with "nodules density","nodules diameter". And "nodules density" had more strong linear correlation than "nodules diameter".2. Pulmonary nodule patients imaging with Discovery CT750HD:Analysis of variance showed:F=167.727, P=0.000<0.005. Comparing any two kinds of pulmonary nodules pathology (squamous carcinoma, adenocarcinoma, pneumonia) showed P<0.005. So the spectrum curves slope had a marked difference between different pulmonary nodules pathology.ConclusionThe Discovery CT750HD results indicated that SECT can alleviate beam hardening effect, acquire more accurate CT numbers than MECT, and get the best CNR at65keV. The CT numbers of73keV had some differences with standard CT numbers, but were more accurate than65keV. The spectrum curves slope of pulmonary nodules was positively related with nodules density, nodules diameter, nodules density was more obviously. The spectrum curves slope of pulmonary nodules also had differences between different pulmonary nodules pathology.

          CT能譜成像在孤立性肺結(jié)節(jié)診斷中的應(yīng)用

中文摘要6-9Abstract9-11符號說明12-13前言13-15第一部分15-28    材料與方法15-17    結(jié)果17-21    討論21-28第二部分28-32    材料與方法28    結(jié)果28-29    討論29-32結(jié)論32-33附圖33-38參考文獻(xiàn)38-42綜述42-58    綜述參考文獻(xiàn)50-58致謝58-59攻讀學(xué)位期間發(fā)表的學(xué)術(shù)論文59-60學(xué)位論文評閱及答辯情況表60

  本文關(guān)鍵詞：CT能譜成像在孤立性肺結(jié)節(jié)診斷中的應(yīng)用，由筆耕文化傳播整理發(fā)布。