64排CT多期双流混合注射跟踪法在肺动脉成像中的应用

目的：探讨64排螺旋 CT 多期双流速混合对比剂注射跟踪法在肺动脉成像（CTPA）中的可行性。方法：将50例拟诊为肺动脉栓塞（PE）的患者随机分为2组,A 组使用混合注射（对比剂与生理盐水配比1∶4）跟踪法,B 组使用预注射时间-密度曲线法。采用双盲法评价2组的 CTPA 图像质量,测量肺动脉主干及主要分支的 CT 值并进行统计学分析。结果：除1例患者未获得时间-密度曲线外,余49例患者均获得较满意的 CTPA 图像质量,两种方法间图像质量评分的差异无统计学意义（P ＞0．05）。两组中肺动脉主干及分支均显示清晰,其血管腔内的 CT 值在2组间的差异较小且无统计学意义（P ＞0．05）。结论：多期双流速混合注射跟踪法 CTPA 具有对比剂用量小、辐射剂量小、图像质量可与传统的预注射跟踪法相媲美、且受心功能影响较小、操作简单易行等优点,值得在临床工作中广泛推广。     

Imaging of coronary artery anomalies using ECG-gated 64-row computed tomography angiography

Objective

To shed light on coronary artery anomalies among cardiac patients using ECG-gated 64-row MDCTA during assessment of coronary arteries.

Patients and methods

Study included 840 patients out of whom twenty-one patients have congenital coronary artery anomalies. Patients were examined using ECG gated 64-row MDCT; 80–100 ml contrast agent, followed by a 50 ml saline chaser injected at 5 ml/s, 350 ms gantry rotation time, 0.65 mm detector collimation, ECG tube current modulation and 100–120 kV. Post-processing was done on second workstation including 3D VR, MPR and CMPR images.

Results

Anomalies of the coronary arteries were diagnosed in twenty-one patients. The prevalence of congenital anomalies in this study was 2.5% and included: anomalous origin of right coronary artery in 4 cases (0.48%), anomalous origin of left circumflex artery in 3 cases (0.36%), myocardial bridging of LAD in 12 cases (1.4%) and coronary artery fistula in 2 cases (0.24%).

Conclusion

Coronary artery anomalies are not uncommon among cardiac patients. Myocardial bridging is the most common followed by anomalous origin and proximal course and lastly coronary artery fistula. 64-Row MDCTA is an excellent promising modality and should be the first non-invasive diagnostic tool to rule out such anomalies.     

Three-dimensional computed tomographic angiography of pulmonary vessels.

OBJECTIVE: To assess the image quality of multiple threshold display (MTD) as a new technique for generating three-dimensional (3D) pulmonary computed tomographic (CT) angiographic images. METHODS: We used MTD, a type of shaded surface display (SSD) offering the selection of multiple thresholds and transparencies, to reconstruct 3D-CT angiograms from enhanced helical CT data sets in 33 patients with lung disease. In MTD, eight thresholds of CT values are selected, and transparency is assigned to each. The selected voxels, ranging from -600 to 1,000 Hounsfield Units, were divided into eight classes, and transparency ranging from 0 to 100% was assigned to each. The CT scanner employed was a Toshiba Xvigor. MTD and SSD images were generated by using an Xtension with a Sun SPARC station 20, and they were compared by two radiologists. RESULTS: The image quality of MTD images was superior to that of SSD images (p < 0.01), because the MTD images demonstrated clearly both the major and small vessels. CONCLUSION: MTD is a useful technique for 3D pulmonary CT angiography.     

Findings of bilateral coronary to pulmonary artery fistula in 64-multislice computed tomographic angiography: correlation with catheter angiography

A 63-year-old man, who underwent conventional coronary angiography, because of a finding of a confusing vascular structure, was referred for 64-multislice spiral computed tomography (MSCT). His MSCT showed bilateral coronary-pulmonary artery fistula from both right and left coronary arteries via a dilated fistulous vascular malformation. Considering its reasonably high spatial and temporal resolutions, MSCT is regarded as a valuable technique to clarify the diagnosis in incidentally found equivocal cases of coronary fistula in conventional coronary angiography.     

Detection of myocardial bridging by 64-row computed tomography angiography of the coronaries

INTRODUCTION: Myocardial bridging is a congenital condition in which a section of coronary artery is surrounded by myocardium. Historically, myocardial bridging has been diagnosed by catheter angiography. This study investigates the effectiveness of electrocardiogram-gated 64-slice multidetector computed tomography in detecting myocardial bridging. MATERIALS AND METHODS: We retrospectively reviewed 167 consecutive patients referred for coronary computed tomography angiography between January 4, 2005, and May 24, 2006. We recorded the number of coronary segments exhibiting myocardial bridging and described the location of each according to the American Heart Association classification system. Association of bridging with factors influencing image quality (body mass index and heart rate) was analyzed. RESULTS: Of 152 eligible participants, 49 (32%) showed myocardial bridging. The mid-left anterior descending coronary artery (segment 7) was the most common location accounting for 69% of positive cases. Body mass index and heart rate did not affect detection rates. CONCLUSION: Electrocardiogram-gated 64-slice multidetector computed tomography is a feasible, noninvasive method of detecting myocardial bridging which may offer higher sensitivity than catheter angiography for this diagnosis.     

V/Q SPECT and computed tomographic pulmonary angiography

Planar ventilation and perfusion (V/Q) scintigraphy has been largely displaced by computed tomography pulmonary angiography (CTPA) in recent years for the diagnosis of pulmonary embolism (PE). This change can be attributed to multiple studies that demonstrate CTPA has a reasonable sensitivity and good prognostic value in negative cases, associated with the ability to deliver few indeterminate results and provide an alternate diagnosis in a significant number of patients. However, the technique has significant limitations. The Prospective Investigation of Pulmonary Embolism Diagnosis II (PIOPED II) study has shown a sensitivity of 83%, which is not optimal. However, CT technology has greatly progressed since this time, and therefore it is likely that this number has improved. The PIOPED II study has also shown that there may be a problem in positive or negative predictive value when the imaging results are discordant with the clinical probability. Additional concerns include allergies, contrast nephropathy associated with the use of intravenous contrast in patients with impaired creatinine clearance, suboptimal results in pregnant women, and high radiation exposure. In recent years, V/Q single-photon emission computed tomography has emerged as a mature technique for the diagnosis of PE and has been shown to be clearly superior to planar V/Q. The technique has excellent sensitivity for PE and is not associated with most of the limitations of CTPA, although it has its own set of limitations in patients with very severe chronic obstructive pulmonary disease or with a severely abnormal chest x-ray. V/Q single-photon emission computed tomography can be used as the initial modality for PE diagnosis in a wide variety of situations although CTPA remains invaluable in specific scenarios.     

MSCT血管成像在肺隔离症诊断中的价值评估

目的：探讨MSCT血管成像在肺隔离症诊断中的应用价值。方法：经临床手术及病理证实的肺隔离症患者23例,均行X线平片、MSCT平扫及CTA检查,结合图像后处理技术（MPR、MIP、VR）,分析本病在MSCT检查中的特征性影像学表现。结果：肺隔离症位于左肺下叶16例,右肺下叶7例。表现为肺野内实性肿块者11例;囊性病灶者8例,其中1例为单囊;表现为团片状病灶者3例;表现为单纯主动脉分支与下肺静脉吻合1例。23例隔离肺的供血动脉均发自体动脉,其中19例发自胸主动脉,4例发自腹主动脉。结论：MSCTA各种后处理技术的有机结合可准确、直观地显示隔离肺组织的供血动脉,MSCTA可以作为目前诊断肺隔离症的首选检查方法。     

Interatrial shunt: diagnosis of patent foramen ovale and atrial septal defect with 64-row coronary computed tomography angiography

Purpose  

The aim of this study was to investigate the frequency with which interatrial shunts are found during routine coronary computed tomography (CT) angiography and to describe imaging characterizations of patent foramen ovale (PFO), atrial septal defect (ASD), and atrial septal aneurysm (ASA).     

Diagnostic performance of 64-slice multidetector coronary computed tomographic angiography in women

Background

Diagnostic approach to chest pain in women is challenging, but still under-investigated. The purpose of this study was to assess the diagnostic performance of 64-slice multidetector coronary computed tomographic angiography (CCTA) in women with chest pain.

Methods and Results

We included 606 patients??255 women and 351 men (mean age 61?±?12?years for both)??who had been referred for a CCTA and an invasive coronary angiography (diagnostic standard) because of chest pain, either as part of clinical work-up in two urban medical centers or as part of the multicenter ACCURACY trial. On a patient-based model, the sensitivity, specificity, and positive predictive value (PPV) and negative predictive value to detect ??50% and ??70% stenosis were 98%, 84%, 87%, and 97% and 96%, 83%, 77%, and 97%, respectively, for women and 97%, 83%, 89%, and 95% and 94%, 91%, 90%, and 94%, respectively, for men. There were no statistically significant differences between men and women in diagnostic performance measures except for the PPV of detecting a ??70% stenosis (P?=?.007).

Conclusion

In women with chest pain, 64-slice multidetector CCTA is at least as sensitive and specific as in men. Our findings suggest that CCTA is a promising diagnostic tool for timely detection and/or exclusion of CAD in symptomatic intermediate-risk female populations.     

64层螺旋CT颈部动脉成像的临床应用

目的：探讨64层螺旋CT颈部动脉成像技术的临床应用。方法：回顾性分析65例经64层螺旋CT颈部动脉造影检查病例,使用对比剂跟踪技术,后处理使用容积再现技术（VRT）、最大密度投影（MIP）、多平面重建（MPR）、曲面重建（CPR）、仿真内窥镜（CTVE）等技术重建,分析其发育变异、斑块性质、狭窄程度等情况,并结合临床进行分析。结果：65例130条颈动脉中,34条无异常,颈内动脉瘤8条,粥样斑块并狭窄88条。88条狭窄的颈动脉中,轻度狭窄59条（67.0%）,中度狭窄22条（25.0%）,重度狭窄5条（5.7%）,闭塞2（2.3%）条;130条椎动脉中,正常52条,先天性变异27条,粥样斑块并狭窄46条,椎动脉受增生骨质压迫5条。51条狭窄的椎动脉中,轻度狭窄40条（78.4%）,中度狭窄8条（15.7%）,重度狭窄3条（5.9%）。结论：应用64层螺旋CT颈部CTA检查,可同时完成颈动脉与椎动脉血管成像,准确显示血管病变的类型、程度,为临床治疗提供科学的依据。     

80kV64排多层螺旋CT低辐射肺动脉成像

目的 研究80 kV 管电压64排多层螺旋CT低辐射肺动脉成像的可行性。方法 64名志愿者随机分为2组。观察组35例采用80kV管电压CT结合右头臂静脉作为团注追踪(bolus tracking) 监测点进行肺动脉成像,对照组29例采用120kV管电压,延迟时间采用团注测试峰值时间+0.7 s,进行肺动脉成像。测量容积CT剂量指数(CTDI_vol)、剂量长度乘积(DLP),计算加权CT剂量指数(CTDI_w)和有效剂量(E),测量肺动脉强化后CT值和背景噪声,计算信噪比(SNR)和对比噪声比(CNR)。5分法对两组图像质量进行目测评分。对DLP、E、SNR、CNR进行t检验;采用Mann-Whitney U检验比较两组图像目测评分结果。结果 观察组DLP和E分别为(146.5±7.6)mGy·cm和(2.5±0.1)mSv,对照组DLP和E分别为(313.4±13.5) mGy·cm和(5.3±0.2) mSv,两者差异有统计学意义(P＜0.001),观察组的辐射剂量低于对照组。图像质量量化评价:观察组和对照组的SNR分别为32.6±3.6和31.35±2.0,差异无统计学意义(P=0.089)。观察组和对照组CNR分别为28.5±3.4和27.6±1.1,差异无统计学意义(P=0.18)。目测评分结果:观察组为5分8例,4分26例,3分1例;对照组为5分5例,4分24例,差异无统计学意义(P=0.76)。结论 80 kV 64排多层螺旋CT结合右头臂静脉作为bolus tracking 监测点可以减少辐射剂量,同时不降低图像质量,是肺动脉造影的首选检查方法。     

80 kV 64排多层螺旋CT低辐射肺动脉成像

Objective To assess the feasibility of minimizing radiation doses using 80 kV 64-row muhidetector computed tomography on pulmonary angiography.Methods 64 volunteers were derided into 2 groups to undergo MDCT pulmonary angiography(collimation,64×0.625 mm;pitch,1.204).The observed group consisting of 35 patients were for pulmonary angiography with 80 kV voltage,300 mAs,0.75 s/roation.The control group consisting of 29 patients were for pulmonary angiography with the standard tube voltage (120 kV),200 mAs,0.5 s/roation and time delay using the peak time on bolus test added 0.7 s.Volume computed tomography dose index (CTDIvol),dose length product (DLP),pulmonary vessel enhancement and back noise were quantified.Signal-noise-ratio (SNR),contrast-to-noise-ratio (CNR),weighted computed tomography dose index (CTDIw) and effective dose (E) were calculated.Results of the two protocols were compared by using t test.Two radiologists used five-point scale to subjectively score arterial enhancement and depiction of small arterial detail.The scores were compared with Mann-Whitney U test.Results The 80 kV protocol had a significantly lower DLP and E than the 120 kV protocol[(146.5±7.6)mGy·cm vs(313.4±13.5)mGy·cm,P<0.001]and [(2.5m±0.1)mGy vs (5.3±0.2)mGy,P<0.001],respectively.The 80 kV protocol and the 120 kV protocol had identical SNR(32.6±3.6 vs 31.3±2.3;P=0.089) and CNR (28.5±3.4 vs 27.6±1.1;P=0.18).No significant difference was found between the two protocols on scores for arterial enhancement and depiction of small arterial detail ( P=0.76).Conclusions 80 kV 64 slices MDCT combined with right brachiocephalic vein as the monitoring site for bolus tracking could be the first choice of pulmonary angingraphy.It can reduce the radiation dose without sacrificing the image quality.     

The added value of spiral computed tomographic angiography after lung scintigraphy for the diagnosis of pulmonary embolism

OBJECTIVES: The objectives of this study were to evaluate the added clinical value of spiral computed tomographic angiography (CTA) after ventilation-perfusion lung scintigraphy (V/Q) for the management of patients with suspected pulmonary embolism (PE). METHODS: Of 987 patients who had V/Q during 2001, 64 patients (6%) had CTA performed for further evaluation. V/Q and CTA findings were retrospectively analyzed by 2 clinicians who were blinded to the patients' outcome. Patient management was determined based on clinical and V/Q data and was reassessed after the addition of CTA data. RESULTS: CTA was performed in 2 patients with normal V/Q, 16 patients with low probability, 28 patients with intermediate, 4 patients with high probability, and 14 patients with nonconclusive V/Q. Three patients (19%) with low probability, 9 (32%) with intermediate probability, 4 (29%) with nonconclusive, and 4 (100%) with high probability V/Q had PE diagnosed by CTA. CTA findings changed the management in 2 patients (13%) with low probability, 15 (54%) with intermediate probability, and 4 (29%) with nonconclusive V/Q. CONCLUSION: In our institution, V/Q remains the main imaging modality for evaluation of patients with clinically suspected PE. CTA was performed after V/Q in 6% of patients. Patients with intermediate probability and those with nonconclusive V/Q, and to a much lesser extent, patients with low probability V/Q could benefit from the addition of CTA after V/Q. In patients with normal V/Q and those with high-probability V/Q, the addition of CTA does not seem to influence patient management.     

Utility of 64-row multidetector computed tomography in diagnosis and management of small bowel obstruction

Purpose

The goal of the study was to assess and confirm the role of 64-slice multidetector computed tomography (MDCT) with its new applications for diagnosis and its impact on management of small bowel obstruction.

Spiral computed tomographic pulmonary angiography for investigating suspected pulmonary embolism: clinical outcomes.

PURPOSE: To assess the clinical outcomes of patients who were suspected of having acute pulmonary embolism and underwent spiral computed tomographic pulmonary angiography (CTPA) for diagnosis. METHODS: We evaluated the clinical outcomes of 62 patients with suspected pulmonary embolism; 82 CTPA scans were performed in a 15-month period. Clinical outcomes were recorded for all patients for a minimum of 3 months. RESULTS: Acute pulmonary embolism was diagnosed and treated in 11 (18%) of the 62 patients evaluated via CTPA. Scans of the other 51 (82%) patients were negative for pulmonary embolism. Seven (14%) of these patients died during the 3-month follow-up period; pulmonary embolism was considered to be a contributing factor in 1 of these deaths. Seven (14%) of the 51 patients were lost to follow-up, and 37 (74%) showed no evidence of disease at least 3 months after a negative CTPA study. Despite the presence or absence of an acute pulmonary embolism, an alternate or additional diagnosis was made on 32 (52%) CTPA scans. CONCLUSION: Spiral CTPA can be effectively used to rule out clinically significant pulmonary emboli and also serves to provide alternate diagnoses in patients who do not have a pulmonary embolism.     

Three-dimensional computed tomographic angiography with computed tomographic colonography for laparoscopic colorectal surgery

Purpose

To prospectively correlate the preoperative vessel anatomy in three-dimensional computed tomographic angiography with computed tomographic colonography (3D-CTA with CTC) with that in laparoscopic surgery for colorectal cancer.

Methods

The study protocol was approved by our institutional review board. The study population consisted of 101 patients with colon cancer who underwent 3D-CTA with CTC between June 2016 and January 2018. Two radiologists assessed the branching patterns of sigmoid arteries (SAs) and right colonic artery (RCA), the position between the ileocolic artery (ICA) and superior mesenteric vein (SMV), and the existence of an accessory middle colonic artery (aMCA). The vessel anatomy on 3D-CTA with CTC was correlated with that of intraoperative findings.

Results

Ninety-eight examinations (97.0%) were technically successful. Between preoperative and intraoperative vessel anatomy, the branching patterns of SAs were concordant in all 29 cases with rectosigmoid and descending colon cancer. The branching patterns of RCA and the position between the ICA and SMV were completely concordant in 32 cases of cecal and ascending colon cancer. No aMCA was identified either intraoperatively or by imaging analysis.

Conclusions

3D-CTA with CTC guided the surgeons to determine the resection margin of the relevant vessels for laparoscopic colorectal surgery.

     

Projection-based bolus detection for computed tomographic angiography

Computed tomographic (CT) angiography is important for imaging studies on cardiovascular structures, peripheral vessels, and solid organs. In practice, a CT angiography scan is triggered by the bolus arrival at a prespecified anatomical location, which is determined using CT fluoroscopy. In this article, we propose a projection-based method adapted from the Grangeat formula to detect the bolus arrival. Then, we evaluate our new method in numerical and animal studies. Our results indicate that this method allows significantly better temporal resolution and is computationally more efficient, as compared with the image-based methods.