李小明浦 江　董宏宇

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螺旋CT多期混合注射跟蹤法在肺動(dòng)脈栓塞診斷中的應(yīng)用價(jià)值

李小明①唐山市中醫(yī)醫(yī)院放射科 河北 唐山 063000浦 江①董宏宇①

[摘要]目的：研究螺旋CT肺動(dòng)脈成像(CTPA)采用多期雙流速混合注射跟蹤法在肺動(dòng)脈栓塞診斷中的應(yīng)用價(jià)值。方法：選取50例肺動(dòng)脈栓塞患者，采用隨機(jī)數(shù)表法將其分為對(duì)照組與觀察組，每組25例。兩組患者均采用256層CTPA，其中對(duì)照組患者采用常規(guī)預(yù)注射時(shí)間密度曲線法，觀察組采用對(duì)比劑混合注射跟蹤法，由CT科2名醫(yī)師采用“雙盲法”評(píng)估兩組患者成像質(zhì)量以及肺動(dòng)脈主干的定量分析。結(jié)果：對(duì)照組患者均獲得滿意的時(shí)間-密度曲線，常規(guī)5項(xiàng)影像質(zhì)量評(píng)分結(jié)果顯示兩種成像方法圖像質(zhì)量評(píng)分比較無(wú)差異；兩組患者肺動(dòng)脈主干、分支成像清晰程度評(píng)分以及血管腔內(nèi)CT值比較差異無(wú)統(tǒng)計(jì)學(xué)意義(t=1.892，t=1.952，t=1.832；P＞0.05)，但觀察組患者CTPA檢查應(yīng)用對(duì)比劑劑量明顯低于對(duì)照組，患者術(shù)中心率、血壓變化率明顯低于對(duì)照組，差異有統(tǒng)計(jì)學(xué)意義(t=2.315，t=1.958，t=2.982；P＜0.05)。結(jié)論：CTPA肺動(dòng)脈成像中采用多期雙流速混合注射跟蹤法可在保證圖像質(zhì)量以及診斷價(jià)值的基礎(chǔ)上，有效降低檢查應(yīng)用對(duì)比劑劑量以及對(duì)心功能的影響，且檢查相對(duì)較為簡(jiǎn)單、安全，具有臨床應(yīng)用及推廣價(jià)值。

[關(guān)鍵詞]多層螺旋CT；多期雙流混合注射跟蹤；肺動(dòng)脈栓塞；對(duì)比劑

[First-author’s address] Department of Radiology, Tangshan City Chinese Medicine Hospital, Tangshan 063000, China.

肺栓塞(pulmonary embolism，PE)是指因內(nèi)源性、外源性栓子阻塞肺動(dòng)脈及其分支，導(dǎo)致肺循環(huán)障礙的臨床病理生理綜合癥，一般以肺血栓栓塞癥(pulmonary thromboembolism，PTE)最為常見，并根據(jù)血栓性栓子栓塞的類型可分為脂肪栓塞、羊水栓塞、空氣栓塞、異物栓塞和腫瘤栓塞[1]。

肺動(dòng)脈栓塞后可直接導(dǎo)致患者肺循環(huán)異常以及肺功能降低，進(jìn)而發(fā)展為肺出血、肺梗死，患者主要表現(xiàn)為呼吸困難、胸痛、咯血及咳嗽等。肺動(dòng)脈栓塞具有較高的病死率與致殘率，因此對(duì)于肺動(dòng)脈栓塞應(yīng)及早診斷并給予針對(duì)性治療措施，對(duì)提高患者臨床治療效果、降低病死率及改善生活質(zhì)量具有重要意義[2]。本研究通過對(duì)比CT肺動(dòng)脈成像(CT pulmonary angiography，CTPA)多期雙流速混合注射跟蹤法與常規(guī)預(yù)注射時(shí)間密度法成像質(zhì)量與對(duì)比劑應(yīng)用，分析多期雙流混合注射跟蹤法在肺動(dòng)脈栓塞診斷中的應(yīng)用價(jià)值。

1　資料與方法

1.1 一般資料

選取2014年1月至2015年1月唐山市中醫(yī)醫(yī)院收治的50例肺動(dòng)脈栓塞患者，采用隨機(jī)數(shù)表法將其分為觀察組與對(duì)照組，每組25例。觀察組中男性18例，女性7例；年齡32～75歲，平均年齡(62.9±4.3)歲；體質(zhì)量指數(shù)(body mass index，BMI)為18.0～25.5 kg/m2，平均BMI為(20.6±1.1)kg/m2。對(duì)照組中男性17例，女性8例；年齡35～80歲，平均年齡為(63.9±4.5)歲；BMI為18.9～25.1 kg/m2，平均BMI 為(19.9±0.5)kg/m2。兩組患者在性別、年齡及BMI等基礎(chǔ)資料比較無(wú)差異，具有可比性。

1.2 納入與排除標(biāo)準(zhǔn)

(1)納入標(biāo)準(zhǔn)：①肺動(dòng)脈造影確診為肺動(dòng)脈栓塞患者；②無(wú)心功能異?；颊摺?/p>

(2)排除標(biāo)準(zhǔn)：①惡性腫瘤患者；②嚴(yán)重心腦血管疾病患者；③嚴(yán)重心肝腎功能不全者；④原發(fā)性免疫缺陷、凝血機(jī)制異?；颊?；⑤對(duì)比劑過敏患者；⑥精神系統(tǒng)疾病患者。

1.3 檢查方法

(1)采用德國(guó)西門子64排Definition螺旋CT進(jìn)行檢查，患者取仰臥位于CT檢查床上，雙手雙肘上舉于頭頂，采用自動(dòng)雙筒機(jī)械高壓注射器以及18 G穿刺套管針進(jìn)行對(duì)比劑注射。對(duì)比劑選擇非離子型碘海醇，掃描參數(shù)為管電流300 mA，管電壓120～140 kV，螺距1.375，掃描時(shí)間2.0 s，重建層厚1.25 mm，重建間隔1.25 ms，準(zhǔn)直器寬度0.625 mm×64 mm，CT掃描范圍為肺尖至膈頂。

(2)觀察組患者采用多期雙流混合注射跟蹤法，混合注射液為對(duì)比劑與0.9%生理鹽水混合，按照對(duì)比劑與生理鹽水1:4的比例配比混合溶液20 ml，采用高壓注射器經(jīng)患者肘前靜脈團(tuán)注，注射速率為5.0 ml/s，后采用雙筒注射器的A筒注射對(duì)比劑4 ml，并通過B筒注射0.9%生理鹽水16 ml，以肺動(dòng)脈干作為檢測(cè)感興趣區(qū)(region of interest，ROI)，閾值為120 HU，雙筒注射器完成注射后監(jiān)測(cè)肺動(dòng)脈干ROI達(dá)120 HU時(shí)行CT掃描，并且在掃描的同時(shí)A筒繼續(xù)推注對(duì)比劑20 ml、B筒推注生理鹽水30 ml，推注操作及順序均由自動(dòng)高壓注射器自動(dòng)無(wú)間隔進(jìn)行。

(3)對(duì)照組采用常規(guī)預(yù)注射，選擇肺動(dòng)脈干作為ROI，雙筒注射器A筒注射對(duì)比劑20 ml，B筒注射生理鹽水20 ml，推注速率為5.0 ml/s，掃描層厚為1.0 mm，不間斷同層連續(xù)掃描方式，掃描時(shí)間設(shè)置為0.5 s，間隔時(shí)間為1.5 s，對(duì)ROI共掃描10次獲取肺動(dòng)脈ROI時(shí)間密度曲線，以增強(qiáng)峰值時(shí)間作為延遲時(shí)間，然后經(jīng)A筒注射20 ml對(duì)比劑，經(jīng)B筒注射30 ml生理鹽水，到達(dá)延遲時(shí)間自動(dòng)啟動(dòng)掃描。

1.4 觀察指標(biāo)

兩組影像結(jié)果經(jīng)PICS傳輸至德國(guó)西門子后處理工作站，采用最大密度投影(maximum intensity projection，MIP)、多平面重建(multiple planar reconstruction，MPR)獲取ROI冠狀、矢狀位重組影像結(jié)果，對(duì)于部分肺動(dòng)脈分支的現(xiàn)象可選擇斜位曲面重組成像。

由CT科2名醫(yī)師采用“雙盲法”評(píng)估兩組患者成像質(zhì)量以及肺動(dòng)脈主干的定量分析，均選取右肺動(dòng)脈、右肺下葉動(dòng)脈及右下肺后基底段動(dòng)脈作為測(cè)量血管?；诔Ｒ?guī)影像評(píng)價(jià)標(biāo)準(zhǔn)為5級(jí)：Ⅰ級(jí)，影像肺動(dòng)脈增強(qiáng)效果不明顯，診斷價(jià)值較低；Ⅱ級(jí)，肺動(dòng)脈亞段分支增強(qiáng)效果不明顯，但伴行肺靜脈強(qiáng)化效果顯著；Ⅲ級(jí)，肺動(dòng)脈段、亞段及伴行靜脈三者之間強(qiáng)化程度比較基本無(wú)明顯差異；Ⅳ級(jí)，可見肺動(dòng)脈段、亞段及分支強(qiáng)化顯著，伴行靜脈輕度強(qiáng)化；Ⅴ級(jí)，肺動(dòng)脈段、亞段及分支強(qiáng)化顯著，但伴行靜脈基本無(wú)強(qiáng)化[3]。其中Ⅰ級(jí)、Ⅱ級(jí)影像結(jié)果不合格，Ⅲ級(jí)為合格；Ⅳ級(jí)、Ⅴ級(jí)影像診斷價(jià)值高，為優(yōu)秀。

1.5 統(tǒng)計(jì)學(xué)方法

采用IBM SPSS 19統(tǒng)計(jì)軟件進(jìn)行統(tǒng)計(jì)學(xué)分析。計(jì)量資料結(jié)果以均值±標(biāo)準(zhǔn)差(x-±s)表示，兩組比較采用t檢驗(yàn)，計(jì)數(shù)資料采用x2檢驗(yàn)，以P＜0.05為差異有統(tǒng)計(jì)學(xué)意義。

2　結(jié)果

2.1 兩組患者影像質(zhì)量比較

兩組患者影像質(zhì)量Ⅰ～Ⅴ級(jí)比較均無(wú)差異，如圖1所示。

圖1　CT肺動(dòng)脈平掃及增強(qiáng)圖像

2.2 兩組患者CT肺動(dòng)脈成像中肺動(dòng)脈分支CT值比較

對(duì)比兩組患者CT肺動(dòng)脈成像中肺動(dòng)脈分支的CT值，患者肺動(dòng)脈干、右下肺動(dòng)脈及后基底段的CT值比較，差異均無(wú)統(tǒng)計(jì)學(xué)意義(t=1.892，t=1.952，t=1.832；P＞0.05)，見表1。

表1　兩組患者CT肺動(dòng)脈成像中肺動(dòng)脈分支CT值比較(x-±s)

2.3 兩組患者對(duì)比劑應(yīng)用劑量及檢查過程中心率、體溫及血壓變化率比較

采集兩組患者對(duì)比劑應(yīng)用劑量以及檢查過程中心率、體溫及血壓變化率并比較，觀察組患者CTPA檢查應(yīng)用對(duì)比劑劑量明顯低于對(duì)照組，患者術(shù)中心率、血壓、體溫變化率明顯低于對(duì)照組，差異具有統(tǒng)計(jì)學(xué)意義(t=2.315，t=2.982，t=1,958；P＜0.05)，見表2。

表2　兩組患者對(duì)比劑應(yīng)用劑量及檢查中心率、體溫及血壓變化率比較(x-±s)

3　討論

肺動(dòng)脈栓塞是臨床上較為常見的心血管呼吸系統(tǒng)疾病，患者若不能得到及時(shí)治療可直接危及生命安全，并且隨著病程的延長(zhǎng)，肺動(dòng)脈栓塞的臨床治療難度也越高，療效與預(yù)后效果也越不理想[4]。對(duì)于肺動(dòng)脈栓塞臨床提倡及早診斷、治療，肺動(dòng)脈造影是目前臨床診斷肺動(dòng)脈栓塞的金標(biāo)準(zhǔn)，可根據(jù)肺動(dòng)脈腔內(nèi)血流的充盈與阻斷程度作為直接征象診斷肺動(dòng)脈栓塞，其敏感性、特異性均＞95%[5-6]。但DSA為有創(chuàng)性檢查，由其導(dǎo)致的嚴(yán)重并發(fā)癥與病死率為0.1%～1.5%，故臨床應(yīng)用嚴(yán)重受限[7]。而無(wú)創(chuàng)性CT肺動(dòng)脈成像具有成像清晰、快速及安全的應(yīng)用特點(diǎn)，目前已在臨床上廣泛應(yīng)用，但目前對(duì)于CT肺動(dòng)脈成像的增強(qiáng)延遲掃描時(shí)間的針對(duì)性研究較少，一般為移植其他部位增強(qiáng)CT掃描的常規(guī)預(yù)注射掃描方法，而人體肺循環(huán)由于生理解剖結(jié)構(gòu)的限制導(dǎo)致其循環(huán)時(shí)間極短，僅為2～4 s，因此，肺動(dòng)脈成像的增強(qiáng)掃描時(shí)間窗較窄，并且受患者的心功能影響導(dǎo)致延遲掃描時(shí)間選擇、控制不理想，因此，準(zhǔn)確掌握肺動(dòng)脈增強(qiáng)峰值時(shí)間非常關(guān)鍵[8-9]。

本研究中采用雙筒雙流注射器能夠?qū)崿F(xiàn)混合對(duì)比劑注射的目的，這種應(yīng)用方法在心臟CT血管成像中已獲得成功應(yīng)用，但在肺動(dòng)脈成像中應(yīng)用尚無(wú)報(bào)道[10]。本研究應(yīng)用的混合對(duì)比劑注射跟蹤法可在保持注射速率恒定的前提下實(shí)現(xiàn)持續(xù)性灌注的目的，有利于檢查中降低患者心臟負(fù)荷，并在一定程度上增加肺動(dòng)脈干ROI區(qū)的CT值，并且設(shè)置掃描閾值可使對(duì)比劑混合液對(duì)血管的強(qiáng)化作用即可滿足要求，可使成像時(shí)肺動(dòng)脈明顯增強(qiáng)而肺靜脈增強(qiáng)不明顯，主動(dòng)脈內(nèi)無(wú)明顯強(qiáng)化，有利于區(qū)分肺動(dòng)脈與肺靜脈，提高肺動(dòng)脈栓塞的檢出率[11-12]。本研究結(jié)果顯示，兩組患者的影像質(zhì)量、肺動(dòng)脈分支CT值等比較差異無(wú)統(tǒng)計(jì)學(xué)意義，但觀察組患者對(duì)比劑劑量、心率、體溫及血壓變化率明顯低于對(duì)照組，直接說明了混合雙流對(duì)比劑注射在保證成像質(zhì)量的同時(shí)，提高檢查的安全性，降低對(duì)比劑應(yīng)用劑量[13]。

通過進(jìn)一步回顧分析表明，256層螺旋CT具有X射線劑量低、旋轉(zhuǎn)速度快及智能化高的優(yōu)點(diǎn)，時(shí)間分辨率遠(yuǎn)高于目前臨床上常規(guī)螺旋CT[14-15]。因此，對(duì)于快速肺循環(huán)中的肺動(dòng)脈干敏感性與特異性較高，患者所受輻射劑量較普通CT設(shè)備降低60%以上[16]。而在本研究中采用多期雙流混合對(duì)比劑跟蹤較常規(guī)預(yù)注射法顯著降低了對(duì)比劑注射劑量，減少了對(duì)比劑應(yīng)用對(duì)患者機(jī)體的影響，提高了檢查的安全性，從而減輕了對(duì)比劑所致的腎不良反應(yīng)[17]。同時(shí)，在自動(dòng)控制的成像模式下，減少了人為因素對(duì)影像質(zhì)量的影響，增加了肺動(dòng)脈干的CT值，提高了影像質(zhì)量進(jìn)而提高肺動(dòng)脈影像的診斷價(jià)值，診斷敏感性和特異性高，能清晰顯示肺栓塞的直接及間接征象，利于隨訪復(fù)查和評(píng)估臨床療效[18]。

綜上所述，CT肺動(dòng)脈成像中采用多期雙流速混合注射跟蹤法可在保證圖像質(zhì)量以及診斷價(jià)值的基礎(chǔ)上，有效降低檢查應(yīng)用對(duì)比劑劑量以及對(duì)心功能的影響，并且檢查相對(duì)較為簡(jiǎn)單、安全，具有臨床應(yīng)用及推廣價(jià)值。

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Research on the application value of spiral CT multi period mixed injection tracking method in the diagnosis of pulmonary embolism/LI Xiao-ming, PU Jiang, DONG Hong-yu// China Medical Equipment,2016,13(1):63-66.

[Abstract]Objective: To investigate the 256 slice spiral CT pulmonary angiography (CTPA) application value by using multiple stage double mixed injection velocity tracking method in the diagnosis of pulmonary embolism. Methods: Fifty patients with pulmonary embolism from 2014 January to 2015 January were treated in our hospital patients as the research object. Using a random number table method, all patients were randomly divided into observation group and control group, 25 cases each group of patients, two groups of patients in our hospital by imaging with 256 slice spiral CT pulmonary artery (CTPA), the control group were treated by routine pre injection time density curve method, was used in the observation group than in mixed injection agent tracking method by two physicians, CT, using the "double-blind" assessment of two groups of patients with image quality and quantification of pulmonary artery trunk. Results: in the control group, 25 patients were satisfied with the time - density curve, the results of 5 conventional image quality scores showed no significant difference between the two imaging methods, was not statistically significant; two groups of patients with pulmonary artery trunk, branch clear imaging score and endovascular CT value had no significant difference(t=1.892, t=1.952, t=1.832; P>0.05), but the observation group patients with CTPA were examined by contrast agent dose was significantly lower than the control group, the patient’s heart rate, blood pressure was significantly lower than the control group(t=2.315, t=1.958, t=2.982; P<0.05), with statistical significance. Conclusion: CTPA with multi period mixed double flow injection method can guarantee the tracking based on image quality and diagnostic value can effectively reduce the contrast agent dosage and application effects of cardiac function, and the examination is relatively simple, safe, has clinical value of application and popularization.

[Key words]Multi slice spiral CT; Multi period mixed injection of double track; Pulmonary embolism; Contrast agent

收稿日期：2015-07-21

DOI:10.3969/J.ISSN.1672-8270.2016.01.020

[文章編號(hào)]1672-8270(2016)01-0063-04

[中圖分類號(hào)]R816.4

[文獻(xiàn)標(biāo)識(shí)碼]A

作者簡(jiǎn)介
李小明,男,(1977- ),本科學(xué)歷，主治醫(yī)師。唐山市中醫(yī)醫(yī)院放射科，從事醫(yī)學(xué)影像診斷工作。