Coronary artery imaging with real-time navigator three-dimensional turbo-field-echo MR coronary angiography: initial experience

PURPOSE: To examine the value of a commercially available three-dimensional (3D) real-time navigator magnetic resonance (MR) coronary angiographic examination for detection of significant coronary artery stenoses, with conventional coronary angiography as the standard of reference. MATERIALS AND METHODS: Twenty-one patients underwent 3D navigator MR coronary angiography immediately before catheterization. Two observers independently graded image quality on a scale from 1 (unreadable) to 5 (excellent), quantified coronary artery visualization, and evaluated the presence of significant (ie, >50% narrowing) stenoses. kappa statistics were used to assess interobserver agreement, and receiver operating characteristic (ROC) analysis was used to assess stenosis detection. RESULTS: For two of 21 patients, MR coronary angiogram quality was insufficient for analysis (mean score < 2). For the remaining 19 patients, the mean image quality scores assigned by observers 1 and 2 were 3.3 +/- 1.0 (SD) and 3.2 +/- 0.9, respectively. A mean of 71% of all coronary artery segments were visible at MR coronary angiography, and there was 91% agreement between the observers (kappa = 0.78). Observers 1 and 2 detected significant stenoses (n = 29) at MR coronary angiography with sensitivities of 44.4% and 55.5%, respectively; specificities of 95.1% and 83.7%, respectively; and 80% agreement (kappa = 0.35). Areas under the ROC curve were 0.817 and 0.795 for observers 1 and 2, respectively. CONCLUSION: Large portions of the coronary arteries can be visualized with MR coronary angiography. Imaging results are not consistently reliable, however. The examination is premature for routine clinical assessment of significant coronary artery stenosis owing to low sensitivity and large observer variability.     

双能量CT冠状动脉成像结合CT心肌灌注诊断冠心病准确性的初步研究

目的 探讨心脏双能量CT冠状动脉造影(DE-CTA)结合CT心肌灌注(DE-CTP)对冠心病诊断的准确性.方法 对31例临床可疑或已知冠心病的患者行心脏双能量CT和负荷-静息SPECT检查,所有患者在1个月内接受导管造影检查.重建冠状动脉DE-CTA和DE-CTP图像用于冠状动脉狭窄程度和心肌灌注缺损的评判,并以冠状动脉造影为参考标准,建立DECT对冠状动脉狭窄诊断价值的基线值,进而计算DE-CTA加DE-CTP对冠心病诊断的敏感性、特异性、阳性预测值、阴性预测值和准确性.结果 28例患者获得满意的图像质量,以冠状动脉造影为参考标准:(1)DE-CTA显示112支冠状动脉,其中41支冠状动脉狭窄≥50%,诊断冠状动脉狭窄的敏感性、特异性、阳性预测值、阴性预测值分别为81%(38/47)、95%(62/65)、93%(38/41)、87%(62/71),准确性为89%(100/112);(2)DE-CTP显示46支狭窄冠状动脉供血区域心肌灌注缺损,诊断狭窄≥50%冠状动脉的敏感性、特异性、阳性预测值、阴性预测值分别为76%(36/47)、85%(55/65)、78%(36/46)、83%(55/66),准确性为81%(91/112);(4)DE-CTA加DE-CTP诊断52支冠状动脉狭窄≥50%,诊断冠状动脉狭窄的敏感性、特异性、阳性预测值、阴性预测值分别为96%(45/47)、89%(58/65)、86%(45/52)、97%(58/60),准确性为92%(103/112).结论 DE-CT一次扫描即能获得冠状动脉解剖学和血流灌注信息,可以对冠心病做出综合性诊断.DE-CTP能够为CTA提供有益的补充.

Abstract：

Objective To evaluate the combination of dual-energy CT angiography (DE-CTA) and dual-energy CT peffusion (DE-CTP) in the diagnosis of coronary artery disease. Methods Thirty-one patients with angina pectoris were examined using dual-source dual energy CT and conventional coronary angiography. For DE-CTA, we used a contrast-enhanced ECG-gated coronary scan protocol with energy levels of two tube detector arrays at 140 and 100 kVp. Two kinds of acquired images were fused for the CT angiogram and further calculated to construct a perfusion map (Siemens DE Heart PBV). The compared the following results: DE-CTA vs. CA, DE-CTP vs. CA to assess the sensitivity and specificity, and further compared DE-CTA plus DE-CTP with CA. Results DECT obtained diagnostic image quality in 28 patients.DE-CTA detected 41/112 arterial stenosis. Using CA as a reference, the sensitivity of DE-CTA was 81%(38/47), specificity was 95% (62/65), positive predictive value was 92% (38/41), negative predictive value was 87% (62/71), and accuracy was 89% (100/112). DE-CTP detected 46 perfusion defects in artery territories. Using CA as a reference, the sensitivity of DE-CTP was 76% ( 36/47), specificity was 85% (55/65), positive predictive value was 78% (36/46), negative predictive value was 83% (55/66),and accuracy was 81% (91/112). DE-CTA plus DE-CTP diagnosed 52 arteries stenosis. Using CA as a reference, combination of DE-CTA and DE-CTP gave sensitivity of 95% ( 45/47 ), specificity of 89%(58/65) , NPV of 97% (58/60), and accuracy of 92% (103/112). Conclusions DECT can provide perfusion blood volume information as well as vessel pathology in one scan. DECT can provide comprehensive diagnosis and improve diagnosis of CAD.     

Coronary arteries: contrast-enhanced MR imaging with SH L 643A--experience in 12 volunteers

PURPOSE: To assess SH L 643A for three-dimensional breath-hold and respiratory-gated magnetic resonance (MR) imaging in the depiction of coronary arteries. MATERIALS AND METHODS: Twelve healthy male volunteers underwent either three-dimensional breath-hold (n = 6) or respiratory-gated (n = 6) coronary MR angiography before and after intravenous injection of 0.1 mmol SH L 643A per kilogram of body weight. For nonenhanced and contrast material-enhanced examinations, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) measurements were obtained. Image quality was assessed in consensus with a five-point scale. Statistical analysis of nonenhanced and contrast-enhanced images was based on a two-tailed paired Student t test. A P value at the.05 significance level was used. RESULTS: Overall statistically significant improvement in CNR was observed after administration of SH L 643A compared with that on nonenhanced images (8.7 +/- 5.3 [SD] vs 23.6 +/- 7.2, P <.01). While SNR of contrast-enhanced images showed improvement over that of nonenhanced images, the difference was not statistically significant (25.4 +/- 0.8 vs 30.2 +/- 16.8, P >.2). Image quality improved from a mean of 3.1 +/- 0.8 for nonenhanced images to 4.0 +/- 0.8 (P <.01) for contrast-enhanced images. CONCLUSION: SH L 643A causes significant improvement of the blood-myocardium contrast enhancement at coronary MR angiography compared with that with nonenhanced sequences.     

双源CT冠状动脉成像在早搏患者中应用的初步体会

目的 探讨应用双源CT对早搏患者进行冠状动脉成像的可行性.方法 对70例临床可疑冠心病的早搏患者进行双源CT增强扫描.利用回顾性心电门控重建心电图编辑前后的图像,以4级记分评价图像质量.比较心电图编辑前后的图像质量采用配对t检验.结果 70例中28例患者的心率波动范围较小[(41.0±18.4)次/min],无需心电图编辑可获得诊断级图像;其余42例患者的心率波动范围较大[(71.4±28.7)次/min],心电图编辑前后的冠状动脉图像质量评分分别为(2.09±1.27)和(1.50±0.79)分,差异有统计学意义(t=13.764,P＜0.01);不可评价的冠状动脉节段比例从24.8%(154/620)降至3.4%(21/620).差异有统计学意义(X2=121.846,P＜0.01).70例患者98.0%(1014/1035)的冠状动脉节段可以评价.结论 拥有高时间分辨率的双源CT能够为早搏患者提供可评价的图像;对于心率波动范围大的患者,心电图编辑能够显著改善图像质量.     

Intra-arterial MR angiography in the iliac system: initial clinical experience with 25 patients

The aim of this study was to evaluate intra-arterial magnetic resonance angiography (MRA) of the iliac arteries. Therefore, 25 consecutive patients (17 male, 8 female) suffering from symptomatic occlusive disease of the lower limbs were investigated prospectively. Catheter angiography was performed before MRA and served as the standard of reference. Contrast-enhanced intra-arterial MRA was performed using a 1.5 Tesla MRI system. Contrast agent (gadodiamide) was injected by a conventional pigtail-shaped angiography catheter placed in the abdominal aorta. Vascular lesions were assessed by four investigators. The degree of stenosis was compared with the findings of conventional catheter angiography. Additionally, the diagnostic quality of the MR angiograms was assessed by the investigators using a semi quantitative five-point scale. All lesions shown by catheter angiography were detected and correctly localized by intra-arterial MRA. MR angiograms exhibit a specificity of 95% and a sensitivity of 96% for stenoses of 50% or more. The diagnostic quality of the images was judged from good to excellent, on average. Intra-arterial MRA exhibits a specificity and sensitivity comparable with intravenous angiography. The image quality appears to be adequate for supporting MR-guided vascular intervention.     

Free-breathing black-blood coronary MR angiography: initial results

The authors developed a free-breathing black-blood coronary magnetic resonance (MR) angiographic technique with a potential for exclusive visualization of the coronary blood pool. Results with the MR angiographic technique were evaluated in eight healthy subjects and four patients with coronary disease identified at conventional angiography. This MR angiographic technique accurately depicted luminal disease in the patients and permitted visualization of extensive continuous segments of the native coronary tree in both the healthy subjects and the patients. Black-blood coronary MR angiography provides an alternative source of contrast enhancement.     

多层螺旋CT和三维屏气MR冠状动脉成像的对比研究

目的比较16层螺旋CT（16 multi-detector CT,16-MDCT）冠状动脉血管造影（CTA）和三维屏气冠状动脉MR血管造影（MRA）的图像质量以及诊断冠状动脉显著性狭窄（＞50%）的准确性.方法40例疑有冠心病患者在3 d内均行冠状动脉CTA和MRA检查,其中31例患者在2周内行冠状动脉造影检查.将冠状动脉分成9个节段（右冠状动脉近、中、远段,左冠状动脉主干,前降支近、中、远段和旋支近、远段）,由2名影像科医生共同对各个节段的图像质量按0～4级评分,比较CTA和MRA上各个节段的图像质量.以冠状动脉造影为标准,计算并比较CTA和MRA诊断31例冠状动脉显著性狭窄（＞50%）各项准确性指标.结果CTA在右冠状动脉中段的图像质量低于MRA,右冠状动脉近段二者无区别,其他节段均优于MRA.冠状动脉造影显示31例患者共有43个节段狭窄＞50%,CTA和MRA分别正确诊断出36和27个,其敏感性、特异性、阳性预测值和阴性预测值分别为83%、84%、49%、97%和63%、90%、55%、93%.结论除右冠状动脉中段,CTA大部分节段的图像质量优于MRA.CTA诊断冠状动脉显著性狭窄的敏感性高于MRA,但特异性低于MRA.冠状动脉CTA和MRA均表现了较高的阴性预测值,对排除冠状动脉狭窄具有临床价值.     

Coronary MR angiography at 3.0 T versus that at 1.5 T: initial results in patients suspected of having coronary artery disease

PURPOSE: To prospectively evaluate the feasibility, image quality, and accuracy of coronary magnetic resonance (MR) angiography at 3.0 T in patients suspected of having coronary artery disease and to prospectively compare these results with those of coronary MR angiography performed at 1.5 T. MATERIALS AND METHODS: The study was approved by the institutional review board, and informed consent was obtained from all patients. Eighteen patients (11 men, seven women; mean age, 63 years; age range, 45-76 years) suspected of having coronary artery disease who were scheduled to undergo elective conventional coronary angiography (reference standard) were included. For coronary MR angiography at 3.0 and 1.5 T, a vector electrocardiographically gated three-dimensional segmented k-space gradient-echo imaging sequence was combined with real-time respiratory navigator gating and tracking. Signal-to-noise ratios (SNRs), contrast-to-noise ratios (CNRs), scores of image quality and sensitivity and specificity for the detection of coronary artery stenosis on a segment-by-segment basis were assessed at 3.0 and 1.5 T. Data were analyzed for statistical differences by using the Wilcoxon matched-pairs test and the McNemar test. RESULTS: The average increase in SNR at 3.0 T with respect to that at 1.5 T was 29.5% for the left coronary artery (LCA) and 31.2% for the right coronary artery (RCA) (P < .001), and the average increase in CNR was 21.8% for the LCA and 23.5% for the RCA (P < .001). Scores of image quality (P = .77) and diagnostic accuracy for the detection of coronary artery stenoses (sensitivity and specificity: 82% and 89%, respectively, at 3.0 T vs 82% and 88% at 1.5 T; P > .99) were identical or almost identical at both field strengths. CONCLUSION: Coronary MR angiography at 3.0 T is feasible in patients suspected of having coronary artery disease and yields significant increases in SNR and CNR, although current techniques do not result in significantly improved image quality and diagnostic accuracy compared with the quality and accuracy at 1.5 T. (c) RSNA, 2005.     

Pituitary adenomas in patients with Cushing disease: initial experience with Gd-DTPA-enhanced MR imaging

To assess the role of magnetic resonance imaging in the evaluation of adrenocorticotropic-hormone (ACTH)-producing pituitary adenomas, and the effect of intravenously administered gadolinium-diethylenetriaminepentaacetic acid (DTPA) on lesion/pituitary contrast, imaging was performed in 13 patients with clinical and chemical evidence of Cushing disease. Images were obtained at 0.5 T before and after the injection of Gd-DTPA (0.1 mmol/kg). Lesions were identified in eight of 12 precontrast and ten of 12 postcontrast studies. In these 12 patients adenomas were found at transsphenoidal surgery. The other patient, with normal images, was found to have an ectopic source of ACTH. Coronal images corresponded remarkably well with the neurosurgeon's intraoperative findings. Serial T1-weighted images disclosed early enhancement of the pituitary gland and delayed enhancement of the cystic adenomas. The discrepancy in times to peak enhancement accounted for improved lesion/pituitary contrast in some early images and for reversal or diminution of lesion/pituitary contrast in later images.     

冠状动脉MR血管成像的研究进展

目前,虽然X线冠状动脉造影仍然是诊断冠状动脉粥样硬化性心脏病(简称冠心病)的金标准,但是其较高费用、有辐射伤害和可能发生严重并发症限制了该技术的广泛使用.此外,在实施冠状动脉造影的患者中,仅有1/3同时进行介入治疗.因此,临床上迫切需要一种无创性影像检查手段在治疗之前能对冠状动脉病变进行准确诊断.     

Multi-detector row CT coronary angiography in patients with cardiomyopathy -- initial single-centre experience

AIMS: To evaluate the diagnostic accuracy of computed tomography (CT) in assessing haemodynamically significant coronary artery stenoses in patients with cardiomyopathy (CM). SUBJECTS AND METHODS: Eighteen patients with CM were approached to undergo CT coronary angiography to evaluate the use of this technique for investigating the presence of significant coronary artery disease (CAD), and also to compare the findings with catheter angiography. RESULTS: On a segment-by-segment analysis the sensitivity, specificity, positive and negative predictive values in the CM group were 66.7, 96.5, 40 and 98.8%, respectively, with 100% accuracy in "whole-patient terms". CONCLUSION: Non-invasive, 16-detector row CT coronary angiography in patients with presumed CM would seem to be a useful clinical tool for the exclusion of significant coronary artery disease. However, the presence of suboptimal contrast opacification in this patient group means that the implication of these results must be interpreted with caution.     

Non-invasive detection of significant coronary artery disease with multi-section computed tomography angiography in patients with suspected coronary artery disease

AIM: The objective of this prospective study was to compare the accuracy of multi-section computed tomography (MSCT) coronary angiography with invasive selective coronary angiography in the detection of significant coronary stenosis (> or =50% lumen diameter narrowing). METHODS: Thirty consecutive patients (mean age 59+/-10 years) with suspected coronary artery disease underwent both invasive coronary angiography and MSCT using a 40-section multidetector row machine with temporal resolution of 53ms. Reconstruction images were performed in eight phases of the cardiac cycle. Images of MSCT and invasive coronary angiography were analysed using the 16-segment model of the American Heart Association. RESULTS: A total of 480 segments from 30 patients were evaluated. Coronary segments distal to a vessel occlusion and segments with coronary stent were not considered for analysis (20 segments in total). Ninety-four (20.4%) segments showed significant (> or =50%) stenosis by invasive coronary angiogram. The accuracy of coronary MSCT was computed on a per segment basis. Average sensitivity, specificity, positive predictive value, and negative predictive value of MSCT were 99, 98, 94, and 99%, respectively. CONCLUSION: This study demonstrated that MSCT is as reliable as coronary angiography at detecting significant obstructive coronary artery disease. In selected groups of patients, it may replace the more invasive and potentially more dangerous conventional coronary angiography.     

Coronary artery anomalies: assessment with free-breathing three-dimensional coronary MR angiography

PURPOSE: To evaluate a simplified protocol by using free-breathing three-dimensional (3D) coronary magnetic resonance (MR) angiography to determine the anatomy of anomalous coronary arteries, in particular the relationship of the vessels to the aortic root. MATERIALS AND METHODS: Twenty-six patients (18 men, eight women; mean age, 50 years; age range, 18-77 years) who had a history of chest pain, palpitations, or syncope and who were suspected of having coronary artery anomalies were examined with free-breathing MR angiography. Multiple 3D volume slabs were acquired at the level of the sinuses of Valsalva by using diaphragmatic navigators for respiratory artifact suppression. The proximal anatomy of the coronary arteries was determined. RESULTS: Six anomalous circumflex arteries originated from the right sinus of Valsalva and passed behind the aortic root. Six right coronary arteries arose from the left sinus of Valsalva and coursed between the aortic root and the right ventricular outflow tract (RVOT). Nine left coronary arteries arose from the right sinus of Valsalva; seven of nine coursed between the aortic root and the RVOT. Five patients had minor anomalies. Overall, in eight patients with anomalous arteries that coursed between the aortic root and the RVOT, conventional coronary angiography could not be used confidently to identify the proximal course. CONCLUSION: Free-breathing 3D coronary MR angiography can be used to identify the proximal anatomy of anomalous coronary arteries.     

MR imaging in patients with nipple discharge: initial experience

PURPOSE: To investigate the potential of magnetic resonance (MR) imaging in patients with nipple discharge. MATERIALS AND METHODS: Between February 1992 and December 1998, 23 patients with nipple discharge underwent contrast material-enhanced MR imaging at 1.5 T. Mammographic findings were negative in 22 of 23 patients and revealed asymmetry in one patient. Galactography was attempted in two patients, with negative findings in one patient and no success in the other. Fifteen of 23 patients underwent excisional biopsy-seven of 15 with MR imaging-guided localization, and one of 15 with mammographic localization. Eight of 23 patients were followed up clinically (range, 7-24 months; mean, 20 months). RESULTS: In 11 of the 15 (73%) patients who underwent excisional biopsy, MR imaging findings correlated with histopathologic findings. MR imaging demonstrated four of six benign papillomas and one of two fibroadenomas as circumscribed, enhancing subareolar masses. Findings of one MR imaging examination were negative, and benign tissue was found at excisional biopsy. MR imaging findings were suspicious in six of the seven patients with excisional biopsy findings of malignancy (regional enhancement [n = 2], ductal enhancement [n = 2], peripherally enhancing mass [n = 1], and spiculated mass [n = 1]). In one of the seven patients, a benign-appearing intraductal mass was identified at MR imaging; excisional biopsy revealed a benign papilloma with an adjacent focus of DCIS. CONCLUSION: MR imaging can help identify both benign and malignant causes of nipple discharge. It potentially offers a noninvasive alternative to galactography.     

Differences between normal subjects and patients with coronary artery disease for three different MR coronary angiography respiratory suppression techniques.

A comparison between three magnetic resonance coronary angiography (MRCA) respiratory motion suppression techniques was performed for both normal subjects and patients with coronary artery disease (CAD). MRCA images were acquired in 17 normal subjects and 15 patients with CAD, using conventional breath-hold MRCA, navigator echo (NE)-guided breath-hold MRCA (LED feedback), and NE-gated MRCA during free respiration. Image quality, diaphragm registration, and total acquisition time were assessed. Overall, there was poor diaphragm registration for conventional breath-holding compared with free respiration (P < 0.001). CAD patients found it significantly more difficult to perform a steady breath-hold (P = 0.04) or attain the same diaphragm position over multiple breath-holds than normal subjects (P = 0.02). All normal subjects, but only 3 of the 15 CAD patients, were able to perform the LED feedback technique (P < 0.001). For normal subjects, image quality was similar between the three respiratory suppression techniques (P = 0.3), while for CAD patients there was an improvement in image quality, for images acquired during free respiration (breath-hold vs. free respiration, P < 0.01). There was no significant difference in the total acquisition times between the breath-hold and free respiration techniques (P = 0.2). There were substantial differences in the effectiveness of MRCA respiratory suppression techniques between normal subjects and CAD patients. In patients, only NE-gated MRCA performed well, requiring minimal cooperation with no increase in total acquisition time. Validation of NE-MRCA techniques should always be performed in patients, as well as normal subjects, to ensure correct evaluation of the technique for the target population.     

Whole-body three-dimensional MR angiography with a rolling table platform: initial clinical experience

A technique for performing whole-body magnetic resonance (MR) angiography with multi-station three-dimensional MR angiography by using a self-developed rolling table platform that integrates the surface coil was evaluated in three volunteers and 10 patients. Use of the surface coil resulted in high signal-to-noise and contrast-to-noise ratios, which translated into sensitivity and specificity of 95.3% and 95.2%, respectively, for detection of significant stenoses (luminal narrowing, >50%) in lower extremity peripheral vascular disease.