Evaluation of coronary artery calcification by ultrafast CT]

A preliminary study was performed to determine whether ultrafast computed tomography (UFCT) is useful as a noninvasive screening examination for predicting coronary artery disease (CAD). UFCT was used to detect coronary artery calcification in 31 patients with angina pectoris (AP) without myocardial infarction. Except for six patients with vasospastic AP, 22 out of 25 patients had detectable calcification in at least one vessel. SVD, DVD and TVD were detected in six of nine patients (67%), seven of seven (100%) and nine of nine (100%), respectively. Based on the findings of coronary calcification by UFCT, the sensitivity, specificity and predictive accuracy of angiographically significant stenosis (greater than 75%) were 94%, 71% and 78% for all branches, respectively. The calcification score for vessels with significant stenotic lesion (n = 48) was statistically higher (p less than 0.01) than that for vessels without stenotic lesion (n = 45). In conclusion, UFCT appears to be useful noninvasive screening examination for detecting CAD, although a prospective study in a large number of patients will be necessary to establish the value of this new method more reliably.     

Carotid artery calcification in the black population: a retrospective study on panoramic radiographs

OBJECTIVES: To determine the prevalence of carotid artery calcification on panoramic radiographs in the Black population. METHODS: Panoramic radiographs of 700 adult male and female Black dental outpatients from the Medical Center of Louisiana Charity Hospital were examined for any unusual radiopacity adjacent to or just below the intervertebral space between C3 and C4. RESULTS: Three (0.43%) of the 700 patients, with ages ranging from 46 - 77-years-old, had one or more unusual radiopacities in the region of interest. All three were female. CONCLUSION: It is uncommon to find radiopacities adjacent to or just below the intervertebral space between C3 and C4 in the general Black population.     

Carotid artery calcification seen on panoramic dental radiographs in the Asian population in Japan

OBJECTIVES: To determine the frequency of carotid artery calcification (CAC) seen on panoramic dental radiographs, the relationship between the condition and a history of cerebral infarction (CI), and the history of the risk factors of CI in patients in Japan. METHODS: A total of 2374 individuals whose panoramic radiographs were obtained at their first consultation were reviewed. Result: CAC was found in 95 subjects (4.0%) and was found at a higher frequency in patients with a history of CI than in those without a history of CI. The modifiable risk factors (a history of hypertension, diabetes and hypercholesterolaemia) and CAC showed significant relationship in the chi(2) test for pairwise comparison. When age and gender were added and all of these risk factors were considered simultaneously in the multiple logistic regression analysis, age and history of hypercholesterolaemia remained statistically significant. CONCLUSIONS: CAC may be seen on panoramic dental radiographs and is related to the patients' general history of CI, and the risk factors of CI in the Asian population in Japan.     

Carotid web and ischemic stroke: a CT angiography study

ObjectivesWe sought to explore the prevalence, demographics, clinical and imaging features of the Carotid web (CaW) on CT angiography (CTA) in patients with cryptogenic and non-cryptogenic stroke through a large-scale retrospective study.Materials and methodsA total of 1662 patients with ischemic stroke and had a neck CTA were retrospectively reviewed. An extensive clinical workup was performed to identify patients with cryptogenic stroke. All neck CTA studies were reconstructed and independently evaluated by two experienced radiologists for presence or absence of CaW on the ipsilateral and contralateral to the stroke side.ResultsThirty-three cases of CaW were eventually diagnosed in patients with ischemic stroke, with a prevalence of 2.2% (33/1489) in a hospital-based series. Twenty-six (26/33, 78.8%) cases of CaW were ipsilateral to the stroke side. There are 18 ipsilateral CaWs (18/285, 6.3%) in cryptogenic stroke patients, and eight ipsilateral CaWs (8/1204, 0.7%) in non-cryptogenic stroke, yielding an odds ratio of 10.1. Cryptogenic stroke patients with ipsilateral CaW were relatively young with a higher prevalence of women. The interrater and intrarater agreement on the CTA based diagnosis of CaW were substantial.ConclusionsOur results demonstrate a strong correlation between the CaW and cryptogenic stroke in large Asian study population. CTA is the imaging modality of choice for detecting CaW.     

Effect of CT digital image compression on detection of coronary artery calcification

Purpose: To test the effect of digital compression of CT images on the detection of small linear or spotted high attenuation lesions such as coronary artery calcification (CAC).Material and Methods: Fifty cases with and 50 without CAC were randomly selected from a population that had undergone spiral CT of the thorax for screening lung cancer. CT image data were compressed using JPEG (Joint Photographic Experts Group) or wavelet algorithms at ratios of 10:1, 20:1 or 40:1. Five radiologists reviewed the uncompressed and compressed images on a cathode-ray-tube. Observer performance was evaluated with receiver operating characteristic analysis.Results: CT images compressed at a ratio as high as 20:1 were acceptable for primary diagnosis of CAC. There was no significant difference in the detection accuracy for CAC between JPEG and wavelet algorithms at the compression ratios up to 20:1. CT images were more vulnerable to image blurring on the wavelet compression at relatively lower ratios, and "blocking" artifacts occurred on the JPEG compression at relatively higher ratios.Conclusion: JPEG and wavelet algorithms allow compression of CT images without compromising their diagnostic value at ratios up to 20:1 in detecting small linear or spotted high attenuation lesions such as CAC, and there was no difference between the two algorithms in diagnostic accuracy.     

降低冠状动脉钙化伪影的CT技术进展

传统冠状动脉CT血管成像（CCTA）可因冠状动脉钙化而降低诊断效能,致使管腔狭窄程度被高估,进而增加不必要的有创性血管造影检查。随着CT空间分辨力提高、新的去伪影算法、双能CT成像技术、冠状动脉减影技术、迭代重建技术及锐利卷积核重建技术的出现与发展,冠状动脉钙化在心脏CT影像上的伪影得以减轻,CT对冠状动脉钙化病人的诊断效能明显提高。就多种降低冠状动脉钙化伪影的CCTA成像技术进展进行综述。     

Coronary artery calcification detected with ultrafast CT as an indication of coronary artery disease.

To assess the relationship of coronary artery calcification to angiographically detectable disease, the authors evaluated 100 patients less than 60 years of age who underwent clinically indicated coronary angiography and ultrafast computed tomography (CT). The ultrafast CT technique consisted of 3-mm-thick contiguous sections and a 100-msec acquisition time. All patients with clinically significant disease at angiography (defined as at least one stenosis with a diameter narrowing of at least 50%) had some coronary artery calcification present at ultrafast CT (100% sensitivity in this population). The absence of calcification at ultrafast CT had a 100% negative predictive value for clinically significant coronary artery disease. Specificity and positive predictive value were 47% and 62%, respectively. Sensitivity and specificity of ultrafast CT in the detection of patients with angiographically detectable disease were 94% and 72%, respectively. Ultrafast CT of the heart is an anatomically based, noninvasive test with high sensitivity for the detection of coronary artery calcification. Ultrafast CT may be beneficial in the screening of selected populations for the presence of atherosclerotic coronary disease.     

Increased intrathoracic and hepatic visceral adipose tissue independently correlates with coronary artery calcification in asymptomatic patients

Background

Visceral adipose tissue (VAT) is associated with cardiac events, but it is not clear which, if any of the various measures of VAT independently correlate with coronary artery disease (CAD).

Methods

We studied 400 patients undergoing computed tomography to determine coronary artery calcium (CAC) score. VAT was measured in the form of epicardial adipose tissue (EAT) volume and thickness, intrathoracic adipose tissue volume (ITAV), and hepatic steatosis.

Results

Of the 400 subjects, the average CAC score was 112.2 ± 389.3. When each measure of VAT (EAT volume and thickness, ITAV, hepatic steatosis) was added to the traditional model (they were independently associated with greater risk of CAC score ≥100 AU as measured by IDI/NRI (P < .05). On univariable logistic regression analysis, each of the 4 measures of VAT showed association with greater risk of a CAC score of ≥100 AU (OR > 1).

Conclusions

Each measure of VAT is a strong correlate of CAC score ≥100 AU in asymptomatic subjects—these VAT assessments correlate more significantly than do traditional CAD risk factors. This incremental power in the predictive models is likely the result of measurement of a fundamental expression of the metabolic syndrome and consequent proatherogenic derangements.     

冠状动脉钙化超高速CT检查及与冠状动脉造影的对比研究

目的：研究超高速ＣＴ（ＵＦＣＴ）所见冠状动脉钙化与冠状动脉狭窄（＞５０％）之间的关系，并与冠状动脉造影对比评价其预测冠心病的敏感性及特异性。材料与方法：９０例临床怀疑或确诊冠心病患者，年龄在２７～７２岁之间（平均年龄５８．５岁），其中男８１例，女９例。所有患者均行ＵＦＣＴ检查及冠状动脉造影，两种检查时间间隔不逾１个月。ＵＦＣＴ扫描采用单层心电门控触发成像，扫描时间为１００毫秒，层厚为３ｍｍ。钙化灶定义为ＣＴ值＞１３０ＨＵ且面积＞１ｍｍ２者，冠状动脉造影采用常规方法。将ＵＦＣＴ所见钙化与冠状动脉造影对比，并计算其敏感性、特异性。结果：１６０支发现钙化的血管中，７４％有冠状动脉狭窄（＞５０％），１５４支造影证实冠状动脉狭窄（＞５０％）的血管中，７７％发现冠状动脉钙化。年轻组与老年组相比，冠状动脉钙化预测冠心病的敏感性较低而特异性较高。钙化在前降支发病率最高，其次为回旋支、右冠状动脉、左主干。结论：超高速ＣＴ检出冠状动脉钙化简便易行，有较高的敏感性、特异性，可广泛用于临床预测及早期诊断冠心病。     

双层螺旋CT冠状动脉钙化积分评估

目的 :对冠状动脉钙化进行定性判断 ,并对其钙化程度进行积分评估和相关技术探讨。方法 :采用GELightspeed 2 .0螺旋CT ,结合心电门控技术 ,对临床怀疑冠心病及要求体检者共 16例行心脏平扫。结果 :CT成像 ,应用SmartScore软件行冠状动脉钙化积分评估。 9例可见双侧冠状动脉多发钙化 ,3例高积分病例随后行DSA检查 ,进一步判断冠脉狭窄程度 ;3例单支冠状动脉钙化 ;4例未见明显钙化 ,其中 1例右侧冠状动脉密度增高 ,有粥样硬化斑块。结论 :螺旋CT冠状动脉钙化积分评估 ,可作为临床诊断重要辅助参考依据 ,是一种值得推广的技术。     

Detection and quantification of coronary artery calcification with electron-beam and conventional CT

To identify patients with increased risk of having coronary artery disease (CAD), electron-beam computed tomography (EBCT) was used for years for quantifying calcifications of the coronary arteries. The first direct comparison between EBCT and conventional CT was performed to determine the reliability of widely available conventional CT for the assessment of the coronary calcium score. Fifty male patients with suspected CAD were investigated with both modalities, EBCT and conventional 500-ms non-spiral partial scan CT. Scoring of the coronary calcification was performed according to the Agatston method. Forty-two of these patients underwent coronary angiography for the assessment of significant luminal narrowing. The correlation coefficient of the score values of both modalities was highly significant (r = 0.982, p < 0.001). The variability between the two modalities was 42 %. Mean calcium score in patients with significant coronary luminal narrowing (n = 37) was 1104 ± 1089 with EBCT and 1229 ± 1327 with conventional CT. In patients without luminal narrowing (n = 5) mean calcium score was 73 ± 57 with EBCT and 26 ± 35 with conventional CT. Although images of the heart from conventional CT may suffer from cardiac motion artifacts, conventional CT has the potential to identify patients with CAD with accuracy similar to EBCT. Received: 13 July 1998; Revision received: 11 October 1998; Accepted: 14 October 1998     

Cervical collaterals may protect against stroke after blunt vertebral artery injury

The incidence of ischemic stroke reported after blunt vertebral artery injury is lower than that reported after blunt carotid artery injury. Unlike the carotid arteries, the vertebral arteries receive collateral blood flow through ascending cervical branches in addition to a convergent arterial supply with the contralateral vertebral artery. We hypothesize that the incidence of stroke after vertebral artery injury is less than after carotid artery injury in part because of reconstitution of vertebral arteries by cervical collaterals. A retrospective blinded interpretation of angiographic studies in 46 patients with blunt vertebral injury was performed to assess for presence and grade of vertebral artery injury and for the presence of reconstitution of the vessel via cervical collaterals. Follow-up CT scans from the same patients were evaluated for the presence of posterior circulation strokes. There were 55 injured vertebral arteries in the 46 patients, of whom 8 experienced posterior fossa strokes. Two-tailed Fisher exact probability test evaluating the hypothesis that patients with vertebral artery collaterals were less likely to experience posterior fossa strokes reached significance, p < 0.05. Of patients with occlusive (grades IV and V) injuries, those with collateral vessels were significantly less likely to experience posterior fossa strokes (p < 0.01). This result may be considered when weighing the potential risks and benefits of antiplatelet or anticoagulation therapy in patients with occlusive blunt vertebral artery injury.     

Helical and single-slice conventional CT versus electron beam CT for the quantification of coronary artery calcification

OBJECTIVE: We compared electron beam CT with conventional CT to determine the best method for the assessment of the coronary calcium score. We used conventional CT to examine symptomatic and asymptomatic patients suspected of having coronary artery disease. SUBJECTS AND METHODS: One hundred sixty male patients underwent electron beam CT and helical CT with a pitch of 1 (n = 30) and 2 (n = 30) and using a single-slice mode with (n = 50) and without (n = 50) prospective ECG triggering. In another 50 patients, we determined reproducibility for repeated scanning using electron beam CT. For all images, we derived the calcium score according to the Agatston method. We performed regression analysis and determined mean variability. Mean variability was calculated as the ratio of the absolute difference to the mean of the corresponding calcium scores. RESULTS: The correlation coefficients for electron beam CT and all conventional CT modes were very high (range, 0.93-0.98). The mean variability was highest in the helical mode with a pitch of 2 (61.4%) and lowest for the single-slice mode with prospective ECG triggering (25.4%). For repeated electron beam CT, the correlation coefficient and mean variability were 0.99 and 22.1%, respectively. CONCLUSION: ECG-triggered single-slice conventional CT had the best agreement with electron beam CT calcium scores.     

钙化对FFR CT诊断冠状动脉疾病准确性影响的研究

目的研究钙化对冠状动脉CT血管成像(CCTA)测定的血流储备分数(FFR_(CT))诊断冠状动脉疾病准确性的影响。方法回顾性分析行CCTA检查和有创FFR检查的38例病人共50支血管的资料。用Agatston积分法测量50支血管的钙化积分值,以钙化积分值100为阈值,分为A1组(≤100)和A2组(100)。利用c FFR软件进行FFR_(CT)值测定,FFR及FFR_(CT)0.8定义为病变特异性心肌缺血。采用组内相关系数(ICC)计算总体及A1、A2组FFR_(CT)与FFR的一致性。以有创FFR作为参考标准,以血管为分析单位,分别计算总体及A1、A2两组FFR_(CT)的诊断准确度、敏感度、特异度、阳性预测值及阴性预测值,并采用Fisher确切概率法比较2组间的差异。结果总体FFR_(CT)和FFR的ICC系数为0.771(95%CI:0.597~0.870),A1组FFR_(CT)和FFR的ICC为0.819(95%CI:0.633~0.910),A2组FFR_(CT)和FFR的ICC为0.649(95%CI:0.032~0.873)。总体FFR_(CT)诊断敏感度、特异度、准确度、阳性预测值及阴性预测值分别为90.9%、97.4%、96.0%、90.9%、97.4%;A1组和A2组FFR_(CT)诊断敏感度、特异度、准确度、阳性预测值及阴性预测值分别为85.7%、100%、96.9%、100%、96.0%和100%、92.3%、94.1%、80.0%、100%;A1和A2组间诊断效能各指标的差异均无统计学意义(均P0.05)。结论 FFR_(CT)与FFR在冠状动脉狭窄血流评估方面有较好的一致性,研究未显示钙化影响FFR_(CT)的诊断效能。     

Aortic calcification in CT. Correlation with risk factors and cardiovascular diseases

Computed tomography is a much more sensitive method of identifying aortic calcification than conventional radiographic methods. The present study was undertaken to explore the importance of various cardiovascular risk factors with regard to their calcifying effect on the aorta. A total of 2,130 individuals, aged 8-88 years, were included. In all cases continuous 8-mm-thick CT slices were obtained from the thoracic inlet caudally to the adrenal glands. There was a significant relationship between aortic calcification and age, smoking habits, hypertension, diabetes, relative body weight, hyperlipidemia and alcohol consumption. Aortic calcification was demonstrated to be strongly associated with vascular disease.     

Coronary artery calcification identified by CT in patients over forty years of age

In a study of 100 unselected patients forty years of age or older, routine CT of the thorax demonstrated coronary artery calcification in 41%. Calcification of the left anterior descending was most common, occurring in 34%. For patients 60 years of age and over, clinical evidence of coronary artery disease was 1.7 times more common in those with calcification compared to those without; however, for patients under 60, coronary artery disease was 5.5 times more common in those with calcification than those without. Because of the strong relationship that is known to exist between coronary artery calcification and coronary arteriosclerosis, we believe that the incidental discovery of coronary artery calcification on routine CT of the thorax has significance. All patients under 60 with coronary artery calcification discovered on CT should be investigated for hyperlipidemia if this has not been done, and, if they are not known to have a history of coronary artery disease, they should have a stress test and, if positive, arteriography may be warranted.