256层螺旋CT低剂量心脑血管联合成像初步研究

目的 初步探讨256层螺旋CT前瞻性心电门控心脑血管联合成像的图像质量与辐射剂量.方法 回顾性分析57例患者CTA资料.组1:心脑血管联合CTA(n=17),应用大范围前瞻性心电门控行冠状动脉、颈动脉及脑血管一站式扫描;组2:冠状动脉CTA(n=20):前瞻性心电门控行常规冠状动脉成像;组3:常规颈脑血管CTA(n =20).分别测量各组升主动脉根部、双侧颈总动脉起始部、椎动脉起始部、颈内动脉(蝶鞍层面)图像CT值与图像噪声;采用4分法评估冠状动脉图像质量,3分法评估颈脑血管图像质量;分别计算各组的辐射剂量.采用t检验比较组间的图像CT值与噪声;采用Mann-Whitney U检验比较组1与组2冠状动脉图像质量及组1与组3颈脑血管图像质量.结果 组1与组2升主动脉根部CT值[分别为(427±50)、(426±86) HU]、噪声[分别为(30±9)、(31±9)HU]差异均无统计学意义(t值分别为0.058、-0.325,P值均＞0.05);冠状动脉图像质量评分组1与组2均满足诊断需要冠状动脉节段,优良分别达到98.1％( 202/206)、99.6％(244/245);两组间图像质量比较差异无统计学意义(Z=- 0.572,P＞0.05).组1与组3颈总动脉起始部CT值[分别为(474±70)、(348±81)HU]、椎动脉起始部CT值[分别为(447±83)、(328±66) HU]差异均有统计学意义(t值分别为5.043、4.869,P值均＜0.05);颈内动脉(蝶鞍层面)CT值[分别为(370±92)、(367±97)HU]两组比较差异无统计学意义(t=0.111,P＞0.05).组1颈脑血管图像质量评分1分1例,2分14例,3分2例;组3颈脑血管图像质量评分2分7例,3分13例;两组图像质量评分比较差异有统计学意义(Z=-3.306,P＜0.05).组1、组2、组3有效辐射剂量分别为(7.0±0.8)、(3.1±0.4)、(5.0±0.3) mSv.结论 256层螺旋CT大范围前瞻性心电门控心脑血管联合成像可获得满足临床诊断需要的冠状动脉、颈动脉及脑血管图像质量,具有简便、快捷、无创、对比剂使用少、辐射剂量低、客观和重复性强的优势,是一种全新的评估冠状动脉与颈脑血管的良好方法.     

64层螺旋CT冠状动脉成像质量分析

目的评价64层螺旋cT冠状动脉成像（64SCTCA）在诊断冠状动脉疾病中的临床价值。方法收集683例临床可疑冠心病患者SCTCA的完整资料,并在有冠状动脉造影（CAG）作对照且CT血管造影（CTA）图像质量为1、2级的患者中,随机选取30例患者共450个冠状动脉节段作定量评价,并分析冠状动脉CTA诊断不同程度狭窄的敏感性、特异性、阳性预测值及阴性预测值。结果683例患者中556例（81．4％）图像质量为1级,112例（16．4％）为2级,15例（2．2％）为3级,造成图像质量较差的原因主要是搏动伪影及呼吸伪影。所有1级、2级分支,绝大部分的3级分支和部分4级分支可得到良好显示。64SCTCA诊断不同程度冠状动脉狭窄的敏感性及阳性预测值均〉80％,特异性及阴性预测值均〉90％,其中轻度狭窄组最低,敏感性、特异性、阳性预测值及阴性预测值分别为81．2％,96．5％,90．8％,92．4％。结论64SCTCA对于冠状动脉狭窄的评估具有较高的诊断价值．适用于冠心病的筛查,具有重要的临床意义。     

64排螺旋CT冠脉成像在冠心病诊断中的应用

目的 评价64排螺旋CT冠状动脉(冠脉)成像(CTA)在冠心病诊断中的应用价值.方法 以选择性冠脉造影(SCA)结果为金标准,采用64排螺旋CT对68例疑诊冠心病患者的冠脉主干及主要分支272节段进行重建和分析,评价其诊断冠心病的灵敏度和特异度.结果 CTA能够清晰显示冠脉主干及其分支狭窄、钙化、开口起源异常及桥血管病变,CTA发现钙化病变52节段,SCA仅发现钙化病变35节段.CTA诊断冠脉病变的灵敏度96.33%,特异度98.16%,阳性预测值97.22%,阴性预测值97.56%.其中对左主干、左前降支病变及＞75%的病变灵敏度最高,分别达到100%和94.4%.结论 CTA对冠脉狭窄病变、桥血管、开口畸形、支架管腔均显影良好,对冠心病诊断有较高的准确性,对钙化病变诊断率优于冠脉造影,可以作为冠心病高危人群无创性筛选检查及冠脉支架术后随访手段.     

64层螺旋CT对冠状动脉粥样硬化血管狭窄的评价

目的:探讨64层螺旋CT对冠状动脉粥样硬化各种程度血管狭窄的评估价值.方法:120例患者行64层螺旋CT血管造影(CTA)检查评价冠状动脉各段的狭窄程度,并与冠状动脉血管造影(CAG)比较,统计64层螺旋CTA诊断冠状动脉各种程度狭窄的敏感性、特异性、阳性预测值(PPV)和阴性预测值(NPV).结果:64层螺旋CTA评...     

256层螺旋CT冠状动脉成像“双低”扫描的临床应用

目的：探讨256层螺旋CT低管电压、低对比剂用量（“双低”）扫描在冠状动脉疾病诊断中的应用价值。方法52例临床疑诊冠状动脉疾病于本院行256层螺旋CT前瞻性心电门控冠状动脉成像双低扫描（管电压80kV ,对比剂用量0．8ml/kg）的患者资料（A组）,均采用迭代重建算法iDose 5进行图像重建;50例行64层螺旋CT常规冠状动脉成像的患者资料作为对照组（B组）,两组患者均行传统冠状动脉血管造影（CCG ）检查。2名有经验的放射科医师按照15段分段法采用4级图像质量评分法评价两组患者的冠状动脉图像质量,并记录对比剂用量及辐射剂量,以CCG为准,评估两组冠状动脉C T成像的诊断准确率。结果所有患者均成功完成256层CT及64层CT 冠状动脉成像。A组患者共显示冠状动脉677节段,以CCG为标准,敏感度为94．5％,特异度为97．4％,阳性预测值为92．7％,阴性预测值为98．0％,诊断准确率为96．6％。B组冠脉成像患者共显示冠状动脉631节段,敏感度为89．1％,特异度为96．4％,阳性预测值为89．9％,阴性预测值为96．1％,诊断准确率为94．5％。两组患者的平均对比剂用量分别为56．8ml和82．2ml ,辐射剂量分别为1．46mSv和8．37mSv。结论256层螺旋CT低管电压冠脉成像技术结合低对比剂用量及迭代重建算法可实现冠状动脉成像的“双低”扫描,与CAG对比有很好的一致性。     

Diagnostic accuracy of non-invasive 64-slice CT coronary angiography in patients with stable angina pectoris

Multislice computed tomography (CT) is an emerging technique for the non-invasive detection of coronary stenoses. While the diagnostic accuracy of 4-slice scanners was limited, 16-slice CT imagers showed promising results due to increased temporal and spatial resolution. These technical advances prompted us to evaluate the diagnostic performance of 64-slice CT coronary angiography in the detection of significant stenoses (defined as ≥ 50% luminal diameter reduction) versus invasive quantitative coronary angiography (QCA). Thirty-five patients with stable angina pectoris underwent CT coronary angiography performed with a 64-slice scanner (gantry rotation time 330 ms, individual detector width 0.6 mm) prior to conventional coronary angiography. Patients with heart rates >70 beats/min received 100 mg metoprolol orally. One hundred millilitres of contrast agent with an iodine concentration of 400 mgl/ml were injected at a rate of 5 ml/s into the antecubital vein. The CT scan was triggered with the bolus tracking technique. The sensitivity, specificity and the positive and negative predictive values of 64-slice CT were 99%, 96%, 78% and 99%, respectively, on a per-segment basis. The values obtained on a per-patient basis were 100%, 90%, 96% and 100%, respectively. When referral to catheterisation is questionable, CT coronary angiography may identify subjects with normal angiograms and consistently decrease the number of unnecessary invasive procedures.     

64-slice computed tomography assessment of coronary artery stents: a phantom study

Purpose: To compare the use of a new 64-slice computed tomography (CT) scanner with 16-slice CT in the visualization of coronary artery stent lumen.

Material and Methods: Eight different coronary artery stents, each with a diameter of 3 mm, were placed in a static chest phantom. The phantom was positioned in the CT gantry at an angle of 0° and 45° towards the z-axis and examined with both a 64-slice and a 16-slice CT scanner. Effective slice thickness was 0.6 mm with 64-slice CT and 1 mm with 16-slice CT. A reconstruction increment of 0.3 mm was applied in both scanners. Image quality was assessed visually using a 5-point grading scale. Stent diameters were measured and compared using paired Wilcoxon tests.

Results: Artificial lumen reduction was significantly less with 64-slice than with 16-slice CT. Average visible stent lumen was 53.4% using 64-slice CT and 47.5% with 16-slice MSCT. Most severe artifacts were seen in stents with radiopaque markers. Using 64-slice CT, image noise increased by approximately 30% due to thinner slice thickness.

Conclusion: Improved spatial resolution of 64-slice CT resulted in superior assessment of coronary artery stent lumen compared to 16-slice CT. However, a relevant part of the stent lumen is still not assessable with multi-slice CT.     

64层螺旋CT数字减影术对颅内动脉瘤诊断价值研究

目的 评价64层螺旋CT数字减影技术对颅内动脉瘤的诊断价值.方法 对36例蛛网膜下腔出血患者行64层螺旋CT平扫及增强扫描,每例患者均行常规CTA及减影CTA(digital subtraction CTA,DSCTA)重建,以DSA检查结果为标准,对比研究2种重建技术的图像质量、诊断准确性.结果 36例患者共计40个动脉瘤,经DSCTA检出动脉瘤40个,灵敏度、特异度分别为100%,经常规CTA检出动脉瘤37个,灵敏度、特异度分别为92.5%和100%.2组后处理图像质量单项有序行乘列表秩和检验有显著性差异(P＜0.01),DSCTA图像质量优于常规CTA.结论 64层螺旋CT DSCTA可作为筛查及诊断动脉瘤的首选方法.     

Gadolinium-DTPA as X-ray contrast medium in clinical studies

The aim of this study was to investigate the contrast effects of gadolinium (Gd) in patients undergoing digital subtraction angiography (DSA), intravenous urography (IVU) and CT. 15 patients attending for coeliac axis DSA (n = 5), abdominal CT (n = 5) and IVU (n = 5) were injected with 0.3 mmol kg-1 Gd-DTPA, the maximum approved dose. For DSA and IVU, images were categorized as being of diagnostic or non-diagnostic quality. For CT, enhancement was measured in Hounsfield Units (HU). On CT, enhancement with Gd was reproducible in all cases; average peak aortic enhancement was 75 HU but duration was short. On IVU, four of five studies yielded positive pyelograms but all nephrograms were relatively poor. On DSA, all five patients had diagnostic arteriograms and four of five indirect portograms were of diagnostic quality. In all 15 cases, enhancement was weaker than that achieved with routine dosage of iodinated agents. In conclusion, Gd chelates may be clinically useful in X-ray studies under certain circumstances on patients with contraindications to iodinated agents. Higher doses than currently approved would be potentially useful.     

Non-invasive evaluation of coronary artery stent patency with retrospectively ECG-gated 64-slice CT angiography

The aim of our study has been to evaluate the ability of 64-slice computed tomographic angiography (CTA) to assess coronary artery stent patency, relative to selective coronary angiography (SCA). Fifty-five consecutive patients (age range 45–80 years) with 97 previously implanted coronary artery stents underwent 64-slice CTA. The 55 patients comprised 40 subjects (group A) who were referred for follow-up SCA at a mean interval of 9.6 months after stent positioning, and 15 subjects (group B) in whom SCA was clinically indicated. Stent evaluation was performed independently by two blinded readers in terms of image quality and presence of in-stent restenosis (ISR; lumen obstruction of ≥50%). SCA was performed in 41/55 patients; 14 patients refused to undergo SCA after the 64-slice CTA exam. A total of 88 stents in 74 segments were analyzed. Twenty-one of the 74 stented segments were of poor image quality and were not considered for further analysis. Sixty-four-slice CTA detected 12/16 ISR (sensitivity: 75%) and ruled out ISR in 32/37 cases (specificity: 86%). Sixty-four-slice CTA is a valuable modality for follow-up of coronary artery stent patency only in selected patients. Appropriate candidates for follow-up 64-slice CTA should be established based on stent diameter, stent material and type as well as HR and heart rhythm. However, given the number of non-assessable segments, further work would appear necessary before 64-slice CTA can be considered a suitable procedure for broad clinical application in the evaluation of coronary artery stent patency.     

Initial experience with a chest pain protocol using 320-slice volume MDCT

We sought to determine the feasibility and image quality of 320-slice volume computed tomography (CT) angiography for the evaluation of patients with acute chest pain. Thirty consecutive patients (11 female, 19 male, mean age 63.2 ± 14.2 years) with noncritical, acute chest pain underwent 320-slice CT using a protocol consisting of a nonspiral, nongated CT of the entire chest, followed by a nonspiral, electrocardiography-gated CT study of the heart. Data were acquired following a biphasic intravenous injection of 90 ml iodinated contrast agent. Vessel attenuation values of different thoracic vascular territories were recorded, and image quality scored on a five-point scale by two readers. Mean attenuation was 467 ± 69 HU in the ascending aorta, 334 ± 52 HU in the aortic arch, 455 ± 71 HU in the descending aorta, 492 ± 94 HU in the pulmonary trunk, and 416 ± 63 HU and 436 ± 62 HU in the right and left coronary artery, respectively. Radiation exposure estimates ranged between 7 and 14 mSv. The CT protocol investigated enabled imaging of the thoracic aorta, coronary and pulmonary arteries with an excellent diagnostic quality for chest pain triage in all patients. This result was achieved with less contrast material and reduced radiation exposure compared with previously investigated imaging protocols.     

碘禁忌证患者应用钆剂冠脉CTA的探讨

目的：探讨碘禁忌证患者应用钆剂行冠状动脉CTA的可行性。方法：30例不宜使用碘剂患者用钆剂替代行冠脉CTA检查,0.3mmol/kg给药,总量25～52ml不等,注射速率4～5ml/s,应用双源CT7～10s完成扫描。结果：30例均见冠状动脉主干及分支强化显示,主干内CT值为（130.73±26.95）HU,最大值为187HU,最小值为55HU。共有402个节段显示,占总节段数的83.75%（402/480）。显示欠清节段主要是：右冠第4段、前降支第8、10段及旋支第14、15段,全部患者检查前后血清肌酐值均未见异常改变。结论：对不宜使用碘剂而临床病情必需行冠脉CTA检查的患者,利用钆剂替代同样能取得预期效果,迅速明确病因对症治疗,检查前、后应确定肾功能正常,以防肾源性系统纤维化（NSF）发生的可能。     

腹腔动脉CT血管成像固定毫安秒低剂量技术探讨

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.     

Coronary artery stent imaging with CT using an integrated electronics detector and iterative reconstructions: First in vitro experience

BackgroundDespite continuous improvements in CT technology, accurate stent lumen delineation remains challenging.PurposeThe aim was to evaluate the quality of coronary stent lumen delineation with CT using a detector with integrated electronics.MethodsTwelve coronary stents placed in plastic tubes and filled with contrast agent (CT number 250 HU) were imaged with either a 128-section dual-source CT machine equipped with conventional detector or with integrated electronics. On both scanners, images were reconstructed with filtered back projection (slice thickness 0.6 mm; increment 0.4 mm) and sinogram-affirmed iterative reconstruction (slice thickness 0.6 mm; increment 0.4 mm), and with iterative reconstruction (slice thickness 0.5 mm; increment 0.3 mm) on the integrated scanner. Two blinded, independent readers assessed image quality, noise, in-stent diameter, in-stent attenuation, and image sharpness by using signal intensity profiles across stents.ResultsInterreader agreement for image quality assessment was substantial (κ = 0.798). Both readers rated best image quality in data sets from integrated detector at highest spatial resolution (86 or 72% of stents rated best quality). Image noise was significantly lower in data sets scanned with integrated detector, being lowest at 0.6 mm slice thickness (14.3 vs 21.0 HU; P < .001). Differences between measured and true in-stent diameters and differences in attenuation across stents were smallest, and average/maximum image sharpness was highest in data sets from the integrated detector using iterative reconstructions.ConclusionCT coronary stent imaging is significantly improved by using a detector with integrated electronics combined with iterative reconstructions.     

个体化对比剂注射方案在256层CT冠状动脉成像中的应用

目的探讨个体化对比剂注射方案在256层CT冠状动脉成像中的应用价值。方法 100例临床怀疑冠心病需接受冠状动脉CT(CTA)检查者,按照对比剂注射方案个体化原则,对比剂总量(ml)=患者体重(kg),对比剂流率ml/s=对比剂总量/(扫描时间+8)ml/s,同样流率追加30ml生理盐水}进行冠脉CTA检查,测量升主动脉根部左冠开口处CT值并对冠状动脉的显示进行评分,分析对比剂注射方案个体化的可行性。结果按照个体化对比剂注射方案行冠脉CTA检查后,100例检查者升主动脉根部左冠开口处平均强化程度为(420.19±56.59)HU,冠状动脉显示评分得3分比例为88.78%,得2分比例为11.22%,无得1分者。结论个体化对比剂注射方案在256层CT冠状动脉成像中具有良好的应用价值。     

16层螺旋CT在下肢动脉闭塞性疾病中的应用价值

目的:探讨16层螺旋CT血管成像术在诊断下肢动脉闭塞性疾病中的应用价值。方法:对42例临床疑为外周动脉闭塞性疾病的患者行下肢动脉16层螺旋CT血管造影(CTA),扫描范围从肾动脉水平达足底。薄层重建横断面图像传入HP xw8000工作站,进行血管三维重建。所有患者于CTA检查前或后2周内行数字减影血管造影(DSA)。以DSA为金标准,评价CTA诊断的准确性。结果:在882个动脉节段中,870个节段在CTA与DSA均可以显示,在DSA图像上,狭窄闭塞的节段共260个(轻度狭窄32段,中度狭窄24段,重度狭窄44段,闭塞160段),最大密度投影(MIP)显示中度以上狭窄的敏感性、特异性及准确性分别为99.1%、99.7%、99.5%。结论:16层螺旋CT在评估下肢动脉闭塞性疾病方面与常规血管造影结果无明显差别,是下肢动脉闭塞性疾病理想的影像学检查手段,可部分替代DSA检查。     

脑静脉畸形64层CT血管成像的表现

目的探讨64层CT血管成像在脑静脉畸形(cerebral venous malformation,CVM)诊断中的价值。资料与方法对30例经64层CT诊断的CVM患者的CT血管成像(CTA)资料及其中1例CVM患者的CT脑血管灌注(CTP)资料进行回顾性分析,总结其影像学特点。结果动脉期在最大密度投影(MIP)图像上38处CVM病灶可以显示,但30处显影较浅淡;静脉期MIP上38处CVM均清晰显示,可见细小扩张的髓静脉呈典型的水母头状汇入粗大的引流静脉。1例脑出血吸收期患者行CTP,发现在血肿区脑实质血流灌注明显减低,血肿旁脑实质血流灌注稍减低,而CVM引流区域血流灌注显著增高。结论64层CT具有各向同性的优势,脑血管成像可清晰显示CVM具有特征性的影像学表现,同时还可以清晰显示颅内外伴发的其他病变。     

16层螺旋CT冠状动脉造影伪影分析

目的：探讨16层螺旋CT冠状动脉造影伪影表现和成因，提高冠状动脉CT血管造影质量和诊断准确性。材料和方法：回顾性分析400例16层螺旋CT冠状动脉造影中失败及假狭窄诊断的38例图像，以DSA冠状动脉造影为金标准，分析上述病例中的伪影及假狭窄的CT表现。结果：伪影分为呼吸伪影、心律不齐伪影、冠状动脉搏动伪影、上腔静脉高浓度造影剂产生假斑块伪影、冠状动脉重度钙化产生的伪影，上述各种伪影均具有独特的影像特征。结论：准确分析CT冠状动脉成像伪影的影像表现及成因，对提高CT成像质量，减少诊断失误有很大的临床意义。     

320排 CT 及血管成像在肝癌诊断及介入治疗中的优势

目的：探讨320排 CT 在肝癌(HCC)诊断中应用价值及血管成像对介入治疗的指导价值。方法回顾性选取41例行肝动脉栓塞化疗(TACE)HCC 患者,治疗前均行320排 CT 三期扫描及血管重建,观察腹主动脉及其主要分支的起源、走行,肿瘤供血动脉、门静脉癌栓与数字减影血管造影(DSA)图像进行对比分析。结果320排 CT 对于发现直径<3 cm 的小肝癌具有优势,对于肝动脉变异、肿瘤供血动脉、门静脉癌栓的显示与 DSA 一致。结论320排 CT 及血管成像可以准确诊断、评价 HCC 并供血动脉、门静脉癌栓,对介入治疗具有重要的指导意义。     

64层螺旋CT冠状动脉成像诊断冠状动脉狭窄的初步探讨

目的：探讨64层螺旋CT（MSCT）冠状动脉成像对冠状动脉狭窄的诊断价值。方法：53例冠心病患者同期均行64层螺旋CT冠状动脉成像和常规冠状动脉造影（CCA）,以CCA的诊断结果作为金标准,采用美国心脏协会冠状动脉改良分段法,分析745个冠状动脉节段MSCT图像质量及对冠状动脉狭窄的显示情况,得出有意义病变（冠状动脉狭窄率≥500%）MSCT诊断的正确性,并分析钙化对其影响。结果：587个冠状动脉节段图像可以满足诊断要求,158个节段因运动伪影（27个节段）或管壁严重钙化（131个节段）无法进行血管评价。MSCT诊断冠状动脉狭窄的敏感度为93．4％、特异度为97．9％、阳性预测值为93．9％、阴性预测值为97．7％。钙化积分≥1000的患者,MSCT诊断冠状动脉狭窄的特异度、敏感度、阳性预测值、阴性预测值分别为74％、82％、68％、96％。结论：64层螺旋CT冠状动脉成像是一种快速、安全、无创的检查方法,与常规冠状动脉造影检查结果有较好的一致性,可以作为临床怀疑冠心病患者的首选检查方法。