Coronary angiography by computed tomography: coronary imaging evolves

Rapid technological advances have facilitated high-resolution noninvasive coronary angiography using multislice computed tomography. Appropriateness guidelines recently have been published in the Journal of the American College of Cardiology and endorsed by several imaging specialty societies. Clinical studies are now available supporting the use of this method in selected diagnostic situations, particularly when the exclusion of coronary artery disease is of paramount clinical concern.     

Use of spiral and non-spiral computed tomography arterial portography in the detection of potentially malignant liver masses

The present study assesses the usefulness of computed tomography (CT) arterial portography (CTAP) in detecting and defining the number and anatomy of potentially malignant liver lesions. One hundred and one adults studied in 1993 and 1994 were retrospectively reviewed, including patients with primary or secondary tumours for possible resection and patients with non-hepatic malignancies in whom the detection of liver metastases would preclude surgery. Twenty-three patients underwent non-spiral CT studies and 78 had studies on a spiral unit, with 22 of these having single phase and 56 having dual phase studies to overcome artefact problems. The relationship between lesion size and detection sensitivity is critical. On non-spiral studies, the overall lesion detection sensitivity and positive predictive value was 69 and 90%, respectively. Detection sensitivity was 100 and 20% for lesions > 1 cm and < 1 cm, respectively. On single phase spiral CTAP the overall detection sensitivity and positive predictive value was 80 and 66%, respectively. Detection sensitivity for lesions > 1 cm and < 1 cm was 100 and 0%, respectively. On dual phase spiral CTAP the overall detection sensitivity and positive predictive value was 76 and 71%, respectively. For lesions > 1 cm and < 1 cm the sensitivity was 81 and 55%, respectively. Eighteen patients with non-hepatic malignancies with unsuspected metastatic spread did not proceed to major surgery because of liver metastases detected on CTAP. Perfusion artefacts occurred in 30 and 64% of non-spiral and of initial portal venous spiral CTAP studies, respectively. By using the double-phase technique, these artefacts were substantially diminished. In conclusion, CTAP is a valuable tool for assessing the presence, site and size of possible liver tumours and confers a benefit even when previous ultrasound and conventional CT have already been used. In addition, CTAP has a lower limit of useful resolution of approximately 1 cm. Perfusion artefacts can be reduced by a dual phase protocol.     

Myocardial Ischemia Evaluation With Dual-source Computed Tomography: Comparison With Magnetic Resonance Imaging

Introduction and objectives

Computed tomography does not accurately determine which coronary lesions lead to myocardial ischemia and consequently further tests are required to evaluate ischemia induction. The aim of this study was to compare diagnostic accuracy between dual-energy computed tomography and magnetic resonance imaging in the assessment of myocardial perfusion and viability in patients suspected of coronary artery disease.

Methods

A prospective study was performed in 56 consecutive patients (39 men [69.6%]; mean age [standard deviation], 63 [10]; range, 23-81). Computed tomography was performed with the following protocol: 1, adenosine stress perfusion; 2, coronary angiography; and 3, delayed enhancement. Magnetic resonance imaging for the evaluation of stress perfusion and delayed enhancement was performed within 30 days. Two observers in consensus analyzed the perfusion and delayed enhancement images.

Results

We studied 952 myocardial segments and 168 vascular territories. In a per-segment analysis, the sensitivity, specificity, and positive and negative predictive values of computed tomography compared with magnetic resonance were 76%, 99%, 89%, and 98% for perfusion defects, and 64%, 99%, 82%, and 99% for delayed enhancement, respectively. In a per-vascular territory analysis, the same measures were 78%, 97%, 86%, and 95% for perfusion defects, and 72%, 99%, 93%, and 97% for delayed enhancement, respectively. The mean radiation dose was 8.2 (2) mSv.

Conclusions

Dual-source computed tomography may allow accurate and concomitant evaluation of perfusion defects and myocardial viability and analysis of coronary anatomy.     

基层医院多层螺旋CT冠状动脉检查现状分析

目的评估基层医院多层螺旋CT(MSCT)行冠状动脉检查的准确性。方法收集在基层医院已行MSCT检查,提示冠状动脉狭窄患者90例,再经北京阜外心血管病医院行冠状动脉造影确诊,采用Kappa检验比较2种检查方法结果的一致性。结果 MSCT诊断冠心病的准确率为88.9%。诊断冠状动脉狭窄程度的准确率39.0%,诊断左前降支、左回旋支和右冠状动脉的准确率分别为45.5%、37.5%和33.3%。在诊断心肌肌桥两者无一相符,诊断钙化准确率较高为80.0%。MSCT检查冠状动脉各节段的狭窄与冠状动脉造影一致性差。左主干、左前降支、左回旋支和右冠状动脉的Kappa值均0.75。结论基层医院MSCT诊断冠心病的准确率较高,但在诊断血管狭窄程度上准确率较低。     

非酒精性脂肪性肝病的CT灌注研究

随着我国经济的发展,生活水平的提高,生活方式的改变及饮食习惯、饮食结构的改变,使我国非酒精性脂肪性肝病(NAFLD)患病率迅速增加,且呈低龄化发病趋势,已成为医学领域的新挑战,NAFLD的诊治引入关注.     

小覆盖范围CT灌注成像对急性大脑中动脉供血区脑卒中的评价

目的探讨用较小扫描范围的CT灌注成像检查对急性大脑中动脉供血区脑卒中的诊断效能。方法回顾性分析急诊接治的22例连续脑卒中患者,均在发病1～24 h行CT平扫和CT灌注成像检查。应用Z轴80 mm范围灌注参数,得出脑梗死核心区、半暗带的体积。计算半暗带/(半暗带+梗死核心区)比值。根据Z轴长度80 mm的CT灌注结果的治疗方案为基线,将较小覆盖范围获得的结果制定的治疗方案,计算较小范围灌注评价治疗的敏感性与特异性。结果当半暗带/(半暗带+梗死核心区)比值>0.2时,较小覆盖范围应用40 mm范围的CT灌注检查,可以准确评价梗死核心区与半暗带。结论大脑中动脉供血区脑卒中患者,当半暗带/(半暗带+梗死核心区)>0.2时,40 mm的Z轴覆盖范围CT灌注成像能够对病灶的范围与性质做出诊断。     

三维重建在肝切除术前评估中的临床应用效果

正肝切除术经历了不同的手术发展阶段,目前认为精准肝切除是新的肝脏外科理念。传统的影像学检查不能满足精确术前评估要求。利用计算机辅助肝脏及肝内管道结构的三维重建并进行虚拟手术是目前研究热点之一[1]。本文对行肝切除手术患者进行三维可视化重建,据此进行术前评估,观察三维重建在肝切除术中的临床应用效果。1资料和方法1.1研究对象收集2012年3月-2015年3月南阳市第一     

超声内镜与多层螺旋CT门静脉成像对门静脉高压的诊断及评估

超声内镜和多层螺旋CT门静脉成像技术是目前评估门静脉及其侧支循环情况的两种有效检测手段。前者能清晰显示食管壁内外及其周围的血管影像,包括交通支情况,但仍属侵入性操作;后者能完整显示门静脉及其侧支循环的走行及分级,但对直径较小的黏膜下静脉检出欠理想;二者各有优势,对门静脉高压进行全面系统的评估,对个体化治疗及管理具有十分重要的临床指导意义。     

PET-CT显像判断肺癌转移的临床价值

目的探讨PET—CT显像判断肺癌转移的临床价值。方法回顾性分析124例肺癌患者治疗前PET—CT显像结果，并与常规CT扫描结果、病理结果对比。结果PET—CT判断肺癌转移的准确率、灵敏度、特异性、阳性预测值、阴性预测值分别为95．2％、96．7％、94．9％、98．3％、94．9％，常规CT的准确率为73．6％；两者准确率比较，P＜0．01。结论PET—CT显像判断肺癌转移的准确率高，可为临床制定治疗方案提供依据。     

AGA future trends report: CT colonography

BACKGROUND & AIMS: Computed tomographic colonography (CTC) was first described more than a decade ago. Recent advances in imaging hardware and software and results of clinical trials based on new methods for performing and interpreting images suggest that CTC may now be assessed as a method for colorectal cancer screening. METHODS: The Research Policy Committee of the American Gastroenterological Association assembled a task force to review the results of recent clinical trials and quantitative mathematical models pertaining to CTC. The goal of the task force was to assess the current knowledge about CTC and to evaluate the issues that will define its impact. RESULTS: Limitations in evaluating the current state of CTC technology include a wide variation in results of clinical trials. There are as yet insufficient data on the use of CTC in routine clinical practice. Limitations in the use of quantitative mathematical models make predictions based on such models of limited value. The cancer risk and therefore clinical importance of small colorectal polyps detected by CTC and/or nonpolypoid neoplasia not detected by CTC remains largely unknown. CONCLUSIONS: CTC is attractive as a colon imaging modality. It is therefore anticipated that CTC will have a significant impact on the practice of gastroenterology. However, the magnitude of the impact is currently unknown. Whether the ongoing implementation of CTC will increase or decrease the number of referrals for colonoscopy or shift the procedure from colorectal cancer screening to therapeutic interventions (e.g., polypectomy) is unknown at the present time. Multidisciplinary collaboration between gastroenterology and radiology to promote effective implementation and ongoing quality assurance will be important.     

螺旋CT及超声对肝腺瘤的诊断价值

目的分析肝腺瘤螺旋CT及超声表现,评估其诊断价值。方法回顾性分析2009年7月-2015年12月在廊坊市中医医院经病理证实的15例肝腺瘤患者的螺旋CT及超声表现。结果 15例患者超声呈低回声、等回声或高回声。其中7例为单发肝腺瘤,低密度4例、略低密度1例、等密度2例;动脉期呈明显强化5例、中度强化1例、轻度强化1例;门静脉期及延时期呈强化降低3例、等密度2例、渐进性强化2例。8例为多发肝腺瘤,80个病灶,4个病灶(3例)呈混杂密度、40个病灶(4例)呈低密度、36个病灶(4例)呈略低密度;8个病灶(4例)动脉期明显强化,门静脉期及延时期强化降低;3个病灶(1例)动脉期明显强化,门静脉期及延时期呈等密度;18个病灶(2例)动脉期及门静脉期明显强化,延时期强化降低;49个病灶(5例)动脉期中度强化,门静脉期及延时期强化降低;2个病灶(1例)各期未见明显强化。螺旋CT对单发肝腺瘤和多发肝腺瘤的诊断正确率分别为14.3%(1/7)、87.5%(7/8)。结论超声仅能提示占位,但不能定性;螺旋CT三期增强扫描对肝腺瘤的诊断,尤其是对多发肝腺瘤的诊断有较高价值。     

Geographic variations in structure and composition of gallstones and their correlation with brittleness

Abstract Cholesterol gallstones obtained from different geographic regions have been reported to show significant differences in their minor chemical constituents. We undertook the present study with two objectives: (i) to investigate the possible physicochemical and radiological differences beween cholesterol gallstones obtained from Indian and German patients; and (ii) to compare the brittleness of the two stone groups. Forty Indian and 36 German gallstones (matched in size and shape) were subjected to assessment of physical characteristics, in vitro computed tomography (CT) and chemical analysis. German stones more often had a stone density distribution index of ≥50 Hounsfield units (HU) (26 vs 14; P <0.01), peripheral calcification (18 vs 9; P <0.02), maximum CT density ≥ 90 HU (17 vs 9; P <0.05) and significant calcium carbonate (9 vs 5; P <0.05), compared to Indian stones. The in vitro lithotripsy performed with the Siemens Lithostar Plus machine at a constant energy level showed the German stones to be more brittle (easy to fragment), more often requiring <1000 shocks for fragmentation (25/36; 69%) compared to Indian stones (18/40; 45%, P <0.05). Gallstones from different geographic regions may show significant variations in their physicochemical characteristics that may explain the differences in their brittleness to lithotripsy.     

老年性细菌性肝脓肿的多层螺旋CT诊断及治疗

目的总结老年性细菌性肝脓肿的多层螺旋CT(MSCT)影像学特征及其治疗方法。方法回顾性分析2001年3月至2014年2月在灌南县中医院确诊为老年性细菌性肝脓肿的42例患者的临床资料,总结MSCT影像学特征及临床治疗特点。组间比较采用t检验。结果 42例患者中,37例病灶位于肝右叶,5例位于肝左叶;33例为单发病灶,9例病灶表现为多房或蜂窝状征象。MSCT平扫结果示,病灶均表现为较正常肝组织低的低密度灶,CT值约6~40 Hu;动脉期:39例病灶边缘环状强化,3例病灶边缘无强化。内科保守治疗15例,穿刺引流27例。15例行内科保守治疗的患者脓腔直径(3.7±2.1)cm,发热时间为(11.7±4.1)d,平均住院(22.6±5.3)d;27例行穿刺引流治疗的患者脓腔直径(6.3±2.8)cm,发热时间为(7.1±2.2)d,平均住院(13.7±3.1)d,两组比较差异均有统计学意义(P值分别为0.021、0.026、0.006)。结论 MSCT检查能够准确显示脓肿位置、形态,结合患者病史可做出正确的诊断。B超或CT引导下穿刺引流治疗是一种有效、微创、安全的治疗方法,可有效控制发热,加快老年患者恢复。     

多层螺旋CT在老年急性肺栓塞诊断及疗效评估中的价值

目的 探讨CT肺动脉造影（CTPA）对老年急性肺栓塞（PE）的诊断及疗效评估价值。方法 入选2009年1月至2015年1月在复旦大学附属华东医院心内科住院的老年急性PE患者55例,分为严重组（n＝24）和非严重组（n＝31）。比较两组患者在溶栓治疗前后右/左心室短轴最大径比（RV/LV）、上腔静脉最大径、肺动脉最大径及栓塞指数等指标。结果 与溶栓治疗前相比,严重组患者的RV/LV、上腔静脉最大径、肺动脉最大径及栓塞指数在治疗后均显著降低,差异均具有统计学意义（P＜0.05）;非严重组患者的肺动脉最大径和栓塞指数在治疗后显著降低,差异均具有统计学意义（P＜0.05）。结论 CTPA可用于PE的诊断,并能对溶栓后疗效进行评价,具有快速、有效、无创的优势。     

超声造影和增强CT对甲胎蛋白阴性原发性肝癌的诊断价值

目的比较超声造影(CEUS)和增强CT(CECT)对AFP阴性原发性肝癌(PHC)的诊断价值。方法对接受过肝脏CEUS和CECT检查的36例甲胎蛋白(AFP)阴性的PHC患者进行分析,将两种检查方法对AFP阴性PHC的诊断阳性率、病理类型符合率进行比较。结果 CEUS对AFP阴性组诊断阳性率为94.4%,病理类型符合率为86.1%;CECT对AFP阴性组诊断阳性率为88.9%,病理类型符合率为88.9%,CEUS与CECT联合对AFP阴性组诊断阳性率为100%,病理类型符合率为100%。结论 CEUS、CECT及两者联合对AFP阴性PHC均具有较高的阳性诊断率和病理类型符合率。     

Computed tomographic colonography without cathartic preparation for the detection of colorectal polyps

BACKGROUND AND AIMS: We prospectively compared the performance of low-dose multidetector computed tomographic colonography (CTC) without cathartic preparation with that of colonoscopy for the detection of colorectal polyps. METHODS: A total of 203 patients underwent low-dose CTC without cathartic preparation followed by colonoscopy. Before CTC, fecal tagging was achieved by adding diatrizoate meglumine and diatrizoate sodium to regular meals. No subtraction of tagged feces was performed. Colonoscopy was performed 3-7 days after CTC. Three readers interpreted the CTC examinations separately and independently using a primary 2-dimensional approach using multiplanar reconstructions and 3-dimensional images for further characterization. Colonoscopy with segmental unblinding was used as reference standard. The sensitivity of CTC was calculated both on a per-polyp and a per-patient basis. For the latter, specificity, positive predictive values, and negative predictive values were also calculated. RESULTS: CTC had an average sensitivity of 95.5% (95% confidence interval [CI], 92.1%-99%) for the identification of colorectal polyps > or =8 mm. With regard to per-patient analysis, CTC yielded an average sensitivity of 89.9% (95% CI, 86%-93.7%), an average specificity of 92.2% (95% CI, 89.5%-94.9%), an average positive predictive value of 88% (95% CI, 83.3%-91.5%), and an average negative predictive value of 93.5% (95% CI, 90.9%-96%). Interobserver agreement was high on a per-polyp basis (kappa statistic range, .61-.74) and high to excellent on a per-patient basis (kappa statistic range, .79-.91). CONCLUSIONS: Low-dose multidetector CTC without cathartic preparation compares favorably with colonoscopy for the detection of colorectal polyps.     

Should computed tomography coronary angiography be aborted when the calcium score exceeds a certain threshold in patients with chest pain?

Background

There is ongoing debate about whether a computed tomography coronary angiography (CTCA) should be aborted when the calcium score (CS) exceeds a certain threshold in patients with chest pain. The aim of this study was to discover whether specific “cutpoints” regarding coronary artery CS could be determined to predict severe coronary stenoses assessed by CTCA, thus identifying patients amenable to an invasive diagnostic approach.

Methods

294 consecutive patients with chest pain of uncertain cause who were referred for non-invasive diagnostic CTCA were included. Subjects underwent Agatston CS and CTCA using current 64-slice technology.

Results

Severe coronary stenoses were noted in 75 of 294 (25.1%) patients on CTCA. A very high prevalence of severe coronary stenoses was found in patients with CS ≥ 400 (87.0%). The CS had area under the ROC curve 0.86 to predict severe coronary stenoses on CTCA. The best discriminant cut-off point was CS ≥ 400 (sensitivity of 55.3%, specificity of 93.5, positive predictive value of 85.8%, negative predictive value of 84.0%). Multivariable logistic regression analysis controlling for traditional risk factors showed CS ≥ 400 remained an independent predictor of severe coronary stenoses on CTCA (OR 14.553, 95% confidence interval 4.043 to 52.384, p < 0.001).

Conclusions

CS can be used as a “gatekeeper” to CTCA in patients with chest pain. Due to the very high prevalence of severe coronary stenoses in patients with CS ≥ 400, further evaluation with CTCA is not warranted as these patients should be referred to invasive coronary angiography, avoiding the repeated exposure to ionizing radiation and iodinated contrast.