Coronary artery anomalies diagnosed by magnetic resonance angiography

Coronary artery anomalies are uncommon entities that may be associated with sudden death. Because of its 2‐D projection imaging nature, conventional X‐ray coronary angiography may not accurately delineate the origins and course of aberrant coronary arteries with respect to the great vessels. Non‐invasive, cross‐sectional imaging techniques such as coronary CT angiography and magnetic resonance angiography are increasingly used in clinical practice to diagnose coronary artery anomalies. Although this study reviews coronary artery anatomy and selected anomalies as seen with true fast imaging with steady‐state precession magnetic resonance angiography, the information provided is equally applicable to electrocardiogram‐gated coronary CT angiography.     

Giant right coronary artery aneurysm – A rare presentation

Coronary artery aneurysm (CAA) is focal dilatation of a coronary artery 1.5 times or more its normal size (Res Cardiovasc Med, 2016; 5: e32086). Coronary artery aneurysm is found in 1.2–4.9% of diagnostic coronary angiography and 1.4% at post‐mortem (Heart Views, 2014; 15: 13; Clin Cardiol, 2015; 29: 439). The proximal and middle segments of the right coronary artery (RCA) are most commonly involved, followed by the proximal left anterior descending (LAD) and the left circumflex arteries. The left main stem rarely develops aneurysms (Clin Cardiol, 2015; 29: 439). A giant aneurysm is a CAA> 2 cm. Giant coronary artery aneurysms (GCAA) are rare (incidence 0.02%) although cause serious complications. [4] Given the rarity of this disease, there is limited information in the literature on its presentation and there is no consensus on its optimal management option. We report a case of a GCAA with an atypical presentation and describe its management. This will add to the current small database on CAA to provide clinicians a better insight on the disease.     

多排螺旋CT血管造影对冠状动脉-肺动脉瘘的诊断价值

目的:探讨冠状动脉CT血管造影(CCTA)对冠状动脉-肺动脉瘘(CPAF)的诊断价值.方法:回顾性分析21例CPAF患者的CCTA影像学表现和临床资料.结果:21例CPAF患者,其中2例行64排CT、19例行256排CT检查.CPAF单一瘘管15例、多发瘘管6例.CPAF起自右冠状动脉4例、左冠状动脉12例、起自两者5例.伴有动脉瘤形成7例.结论:CCTA可无创、准确地显示CPAF的起源血管及走行、动脉瘤和瘘口大小等重要信息,可作为诊断CPAF的首选方法.     

Sinus valsalva aneurysm on cardiac CT angiography: Assessment and detection

After the advent of ECG gated cardiac CT angiography (CCTA) there has been significant improvement in image quality of the ascending aorta. As a result the sinuses of valsalva are readily assessable. Sinuses of valsalva aneurysm can cause significant dysfunction of the aortic root and annulus and can be congenital or acquired. The aneurysm most commonly originates from the right coronary sinus. Complications related to sinuses of valsalva aneurysm can cause chest pain and can be life threatening. The cardiac imager should actively assess the sinuses of valsalva in every CCTA study.     

Coronary artery anomalies in adults: Imaging at dual source CT coronary angiography

Congenital abnormalities of the coronary arteries have an incidence of 1%, and most of these are benign. However, a small number are associated with myocardial ischaemia and sudden death. Various imaging modalities are available for coronary artery assessment. Recently, multi‐detector CT has emerged as an accurate diagnostic tool for defining coronary artery anomalies. The purpose of this pictorial essay is to review the dual source CT appearance of congenital anomalies of the coronary arteries in adults.     

Quantitative coronary angiography findings of patients who received previous breast radiotherapy

Purpose

To compare the coronary angiographic findings between patients who had previous left sided versus right sided breast cancer radiotherapy (RT).

Materials and methods

Between 1995 and 2009, 12,696 patients who underwent curative RT for breast cancer at Princess Margaret Hospital were screened to assess if they had been investigated with a post-RT coronary angiogram. Two cardiologists, blinded to the laterality of radiation treatment, assessed all angiograms and measured the percentage of stenotic lesions, the mean diameters of each segment of the left anterior descending artery (LAD) and the right coronary artery (RCA) using quantitative coronary angiography (QCA).

Results

Ninety-one patients were included, 49 patients with left sided RT and 42 with right sided RT. The median time from RT to coronary angiogram was 4.2 years (range: 22 days–16.9 years). Seventeen patients (35%) in the left sided RT group and 17 (40%) in the right sided RT group needed coronary revascularization (percutaneous coronary intervention or by-pass surgery). The LAD territory was revascularized in 12 (24%) and 11 (26%) patients, respectively. The proportion of clinically significant stenoses, degree of stenoses and mean vessel diameter were not significantly different between the two groups. In 33 patients who had coronary angiograms >5 years after breast RT (17 left-sided and 16 right-sided), the only statistically significant finding was marginally narrower mid RCA segments among those who had right sided RT: 2.52 mm versus 2.92 mm (P = 0.039).

Conclusions

In our patients, left sided breast cancer RT did not increase the risk of coronary artery disease within the first few years, when compared to right sided RT. However, with the limitation of short duration between radiotherapy and coronary angiogram, late development of coronary artery stenoses 10–15 years after left sided RT could not be excluded.     

肠细膜上动脉供血型肝癌的血管造影分析及介入治疗

目的 研究肠细膜上动脉供血型(即变异肝动脉起源于肠细膜上动脉)肝癌的血管造影表现及插管技术。 方法 回顾分析41例肠细膜上动脉供血型肝癌的DSA及介入治疗资料,统计血管解剖变异的发生率,对其起源、走行、分支、分布等解剖学特征及其与血管插管的关系进行描述和分析。 结果 350例肝癌中,肠细膜上动脉供血型41例(11.9％),其中副肝右动脉15例(36.5％),替代肝右动脉16例(39.0％),肝总动脉8例(19.5％),腹腔动脉干起源于肠细膜上动脉2例(5％)。31例肠细膜上动脉发出替代或副肝右动脉者,29例(94.0％)腹腔动脉造影表现为肝右动脉细小或缺如,肝右叶出现无血管区。RH导管超选择性插管成功25例(61％),未成功者改用Cobra、Simmon导管以及结合微导管技术后获得成功。 结论 肠系膜上动脉供血型肝癌是一种比较常见的肝动脉变异性供血,熟悉其血管变异的特点对肝动脉化疗栓塞术具有重要的意义。     

Diagnostic accuracy of 16‐slice CT coronary angiography in the evaluation of coronary artery disease

Multislice CT coronary angiography (CT‐CA) has emerged as a potential imaging method for coronary artery disease. This study aimed to ascertain the accuracy of 16‐slice CT in the diagnosis of significant coronary stenosis (≥50% reduction of lumen diameter). This mixed retrospective/prospective observational study compared 95 paired 16‐slice CT‐CA and fluoroscopic coronary angiography (FCA) sets. A cardiologist and a radiologist blinded to the FCA findings evaluated CT‐CA images independently by visual estimation. Disagreement between these reporters was arbitrated by a third CT reporter (a cardiologist). A separate cardiologist blinded to CT‐CA findings assessed FCA by visual estimation. Of 1161 coronary segments assessable on FCA, 1103 segments (95%) were assessable on CT‐CA. The CT‐CA correctly diagnosed 147/180 segments with significant stenoses (sensitivity = 82%) and correctly identified 874/923 coronary segments without significant stenoses (specificity = 95%). The positive and negative predictive values of CT‐CA in the diagnosis of coronary segment with significant stenosis were 75 and 96%, respectively. On patient‐based analysis, CT‐CA correctly identified all 68 studies with at least one vessel with significant stenosis (sensitivity = 100%; specificity = 83%). The positive and negative predictive values of CT‐CA in identifying patients with significant coronary stenosis were 94 and 100%, respectively. The 16‐slice CT‐CA showed moderately good sensitivity but very high specificity and negative predictive value in the diagnosis of significant coronary stenosis. The CT‐CA would appear to be a useful ‘rule‐out’ test for patients with low‐risk profile for ischaemic heart disease.     

Discrepancy between computed tomography coronary angiography and selective coronary angiography in the pre‐stenting assessment of coronary lesion length

We aimed to compare the lesion length measured on computed tomography coronary angiography (CT‐CA) with the selective coronary angiography (SCA) lesion length measured on quantitative coronary angiography (QCA). Compared with SCA, CT‐CA has the advantage of showing the lumen and the atherosclerotic plaque in the arterial wall. This prospective observational study involved 44 coronary lesions. Computed tomography coronary angiography was carried out with an electrocardiogram‐gated 16‐slice CT before percutaneous coronary intervention. A cardiologist and a radiologist measured CT lesion lengths in consensus, whereas an interventional cardiologist carried out QCA to obtain SCA lesion lengths independently. The median difference of (CT lesion length − SCA lesion length) was 9.84 mm (95%CI: [7.26, 13.34]). The median difference of (stent length − SCA lesion length) was 7.68 mm (95%CI: [6.29, 9.26]); the median difference of (stent length − CT length) was −2.63 mm (95%CI: [−5.80, 0.05]). The mean ratio of stent length to SCA lesion length was 2.07 (95%CI: [1.83, 2.30]). The mean ratio of stent length to CT‐CA lesion length was 0.97 (95%CI: [0.83, 1.11]). In the subgroup of drug‐eluting stents (17 lesions), the median difference of (stent length − SCA lesion length) was 9.76 mm (95%CI: [6.59, 13.28]); the median difference of (stent length − CT length) was −5.2 mm (95%CI: [−11, 0.5]). The mean ratio of stent length to CT‐CA lesion length was 0.93 (95%CI: [0.68, 1.17]). Computed tomography lesion length was substantially longer than SCA lesion length measured by QCA. Routine practice of choosing stent length based on QCA may underestimate the actual length of target lesion. This may lead to incomplete coverage of the target lesion, particularly when drug‐eluting stents are used.     

Adoption of Expansion Margins to Reduce the Dose Received by the Coronary Arteries and the Risk of Cardiovascular Events in Lymphoma Patients

PurposeMediastinal radiation therapy (RT) in patients with lymphoma implies involuntary coronary artery (CA) exposure, resulting in an increased risk of coronary artery disease (CAD). Accurate delineation of CAs may spare them from higher RT doses. However, heart motion affects the estimation of the dose received by CAs. An expansion margin (planning organ at risk volume [PRV]), encompassing the nearby area where CAs displace, may compensate for these uncertainties, reducing CA dose and CAD risk. Our study aimed to evaluate if a planning process optimized on CA-specific PRVs, rather than just on CAs, could provide any dosimetric or clinical benefit.Methods and MaterialsForty patients receiving RT for mediastinal lymphomas were included. We contoured left main trunk, left anterior descending, left circumflex, and right coronary arteries. An isotropic PRV was then applied to all CAs, in accordance with literature data. A comparison was then performed by optimizing treatment plans either on CAs or on PRVs, to detect any difference in CA sparing in terms of maximum (D_max), median (D_med), and mean (D_mean) dose. We then investigated, through risk modeling, if any dosimetric benefit obtained with the PRV-related optimization process could translate to a lower risk of ischemic complications.ResultsPlan optimization on PRVs demonstrated a significant dose reduction (range, 7%-9%) in D_max, D_med, and D_mean for the whole coronary tree, and even higher dose reductions when vessels were located 5- to 20-mm from PTV (range, 13%-15%), especially for left main trunk and left circumflex (range, 16%-21%). This translated to a mean risk reduction of developing CAD of 12% (P < .01), which increased to 17% when CAs were located 5- to 20-mm from PTV.ConclusionsIntegration of CA-related PRVs in the optimization process reduces the dose received by CAs and translates to a meaningful prevention of CAD risk in patients with lymphoma treated with mediastinal RT.     

Prevalence of significant extracoronary findings on multislice CT coronary angiography examinations and coronary artery calcium scoring examinations

The purpose of the study was to review the prevalence of significant extracoronary findings in patients who underwent multislice CT coronary angiography examinations and coronary artery calcium scoring examinations. We reviewed the reports of 295 consecutive patients who underwent multislice CT coronary angiography examinations and 140 consecutive patients who had separate coronary calcium scoring examinations from September 2004 to March 2006 in our department's radiology information system. Additional investigations carried out as a result of these findings were also recorded. Fifty-six (19%) out of 295 patients had significant extracoronary findings on coronary CT angiography requiring clinical or radiological follow up. There were 60 significant extracoronary findings. These included 24 patients who had pulmonary abnormalities, 4 who had mediastinal abnormalities, 20 who had upper abdominal abnormalities and 5 who had non-coronary cardiac abnormalities. Three patients had both pulmonary and upper abdominal abnormalities. Eleven (8%) out of 140 patients had significant pulmonary, breast, mediastinal, upper abdominal and cardiac abnormalities on coronary artery calcium scoring examinations, yielding a total of 12 significant findings. In our experience, 19% of the patients who underwent multislice CT coronary angiography and 8% of the patients who underwent coronary artery calcium scoring examinations had significant extracoronary findings requiring follow up. It is therefore imperative for the reporting physician to review the entire examination after the coronary arteries have been assessed. The prevalence of extracoronary findings on these examinations may be of significance, resulting in additional 'hidden costs' if widespread 'screening' is adopted.     

Elongated eccentric soft coronary plaque: Major diagnostic pitfall on quantitative coronary angiography overpowered by computed tomography coronary angiography and intravascular ultrasound

We describe a significant left anterior descending coronary lesion in a patient with unstable angina pectoris. This lesion was erroneously underestimated using quantitative coronary angiography; however, CT coronary angiography correctly showed a significant, elongated, eccentric, soft plaque that was later confirmed by repeated quantitative coronary angiography with intravascular ultrasound. As showed, CT coronary angiography may offer a reliable non‐invasive alternative to quantitative coronary angiography and intravascular ultrasound by enabling a true 3‐D coronary lumenogram combined with plaque detection and characterization.     

A systematic review of radiation dose associated with different generations of multidetector CT coronary angiography

The purpose of this paper is to perform a systematic review on radiation dose reduction in coronary computed tomography (CT) angiography that is done using different generations of multidetector CT (MDCT) scanners ranging from four-slice to 320-slice CTs, and have different dose-saving techniques. The method followed was to search for references on coronary CT angiography (CTA) that had been published in English between 1998 and February 2011. The effective radiation dose reported in each study based on different generations of MDCT scanners was analysed and compared between the types of scanners, gender, exposure factors and scanning protocols. Sixty-six studies were eligible for inclusion in this analysis. The mean effective dose (ED) for MDCT angiography with retrospective electrocardiogram (ECG) gating without use of any dose-saving protocol was 6.0 ± 2.8, 10.4 ± 4.90 and 11.8 ± 5.9 mSv for four-slice, 16-slice and 64-slice CTs, respectively. More dose-saving strategies were applied in recent CT generations including prospective ECG-gating protocols, application of lower tube voltage and tube current modulation to achieve a noteworthy dose reduction. Prospective ECG-gating protocol was increasingly used in 64, 125, 256 and 320 slices with corresponding ED of 4.1 ± 1.7, 3.6 ± 0.4, 3.0 ± 1.9 and 7.6 ± 1.6 mSv, respectively. Lower tube voltage and tube current modulation were widely applied in 64-slice CT and resulted in significant dose reduction (P < 0.05). This analysis has shown that dose-saving strategies can substantially reduce the radiation dose in CT coronary angiography. The fact that more and more clinicians are opting for dose-saving strategies in CT coronary angiography indicates an increased awareness of risks associated with high radiation doses among them.     

Effectiveness of radioactive tungsten source in the prevention of restenosis in stented porcine coronary arteries

PURPOSE: Intracoronary radiation has shown the potential to inhibit neointimal proliferation in porcine models of restenosis. The objective of this study was to determine whether intracoronary radiation using a new coiled wire of tungsten-188 ((188)W), a pure beta emitter (half-life 69.4 days) is safe. In addition, a dose of 0 Gy, 18 Gy, or 25 Gy prescribed to 2 mm from the center of the source and delivered intraluminally is sufficient to prevent restenosis and free from adverse effects. METHODS AND MATERIALS: Ten domestic swine underwent 13-mm stent implantation (SI) into two arteries, left anterior descending plus either the left circumflex or right coronary artery. After SI, a closed-end lumen radiation catheter was inserted to the treated artery and a 40-mm coiled (188)W source was manually delivered to cover the stented segment and its margins. A total of 20 arteries were randomized to treatment with a radiation dose of 0, 18 Gy, or 25 Gy delivered to 2 mm depth from the center of the source. Four weeks after the procedure, the swine underwent angiography and intravascular ultrasound using automated pullback at 0.5 mm/s. before being killed and the arteries perfusion fixed. Histopathologic and histomorphometric analyses were performed at 28 days after injury and radiation. RESULTS: Irradiation with (188)W at a dose of 25 Gy after SI significantly inhibited neointima formation (intimal area: 1.05 +/- 0.64 vs. 2.75 +/- 0.99 mm(2), p < 0.01) and at an 18 Gy dose of radiation (intimal area: 1.73 +/- 0.49 vs. 2.75 +/- 0.99 mm(2)), as compared to controls. One artery receiving 18 Gy and two arteries receiving 25 Gy were totally occluded at follow-up due to thrombus formation but no edge stenosis was observed in any of the irradiated arteries. CONCLUSIONS: Intracoronary radiation therapy using a new coiled wire of (188)W source delivered after SI appeared to be safe and well tolerated. The radiation doses demonstrated efficacy in reducing neointima formation in the porcine coronary stent injury model.     

Acute coronary thrombosis and myocardial ischemia following chemotherapy of Hodgkin's disease

A 37 year old man without coronary risk factors or known heart disease showed progression of Hodgkin's disease after radiation and multiple chemotherapy. One day after the first cycle of chemotherapy with methotrexate, Ifosfamide and etoposide, he had an acute myocardial ischemia. The creatinin-kinase was elevated up to 325 U/l. Coronary angiography showed a thrombus in the left anterior descending coronary artery (LAD), while the other coronary arteries were normal. Ventriculography showed an apical akinesia. After 7 days of treatment with heparin coronary angiogram was normalized, without any stenosis in the LAD. To our knowledge this is the first documented case of a coronary artery thrombosis and myocardial ischemia after chemotherapy in a patient without coronary heart disease. We conclude that chemotherapy can cause myocardial ischemia by coronary artery thrombosis in patients without prior heart disease.     

Inducible myocardial ischaemia diagnosed using computed tomography dipyridamole stress myocardial perfusion technique

Improved multi-detector computed tomography (MDCT) temporal and spatial resolution allows for the assessment of coronary artery disease, left ventricular systolic function and resting myocardial perfusion defects with high sensitivity and specificity. Here we present a case using a novel combination technique of cardiac computed tomography scanning with dipyridamole stress for the detection of functionally significant coronary disease, and demonstrate that dipyridamole-induced myocardial ischaemia is both detectable and quantifiable by cardiac MDCT.     

Myocardial perfusion imaging with technetium-99m sestamibi SPECT in the evaluation of coronary artery disease

Technetium-99m hexakis-2-methoxy-isobutyl-isonitrile(^99mTc sestamibi) has been used for myocardial perfusion imaging in the evaluation of coronary artery disease (CAD) since 1990. The experience of its use in an Asian population with and without previous myocardial infarction (Ml), diabetes mellitus (DM), hypertension (HPT) and collateral circulation (COL) is reported. One hundred and thirty-nine patients who underwent treadmill exercise testing with ^99mTc sestamibi single photon emission computed tomography (SPECT) and coronary angiogram were studied. The overall sensitivity for the detection of CAD was 91.0% and specificity was 64.7%. For patients without previous myocardial infarction, the sensitivity was 83.8% and specificity was 83.3%. Patients with COL had a higher sensitivity while those with HPT had a lower specificity. Sensitivity was higher in patients with multi-vessel disease (MVD) than single vessel disease (SVD). The overall detection for individual artery stenosis was 74.1% with a specificity of 73.1 %. Amongst the three major coronary arteries, sensitivity was highest for the right coronary artery and specificity was highest for the left circumflex artery. Specificity was higher in patients without MI or COL. We found that the agreement between ^99mTc sestamibi SPECT and coronary angiogram for the extent of CAD was only 52.5%. The concordance rate was higher for patients with MVD than SVD. It is concluded that ^99mTc sestamibi SPECT is a sensitive and specific test for the detection of CAD and localization of disease to individual coronary arteries in our patients with some differences in the subgroups. Agreement between coronary angiogram and ^99mTc sestamibi for the extent of coronary artery disease was also satisfactory.     

Dosimetric comparison between high-precision external beam radiotherapy and endovascular brachytherapy for coronary artery in-stent restenosis

PURPOSE: Several drawbacks of endovascular brachytherapy for the treatment of coronary artery in-stent restenosis may be addressed by high-precision external beam radiotherapy (EBRT). The dosimetric characteristics of both treatment techniques were compared. METHODS AND MATERIALS: The traversed volume of 10 coronary artery stents during the cardiac cycle was determined by electrocardiographically gated multislice spiral CT in 10 patients. By use of this traversed volume, high-precision EBRT treatment plans were generated for stents in the left circumflex (LCx), left anterior descending (LAD), and right coronary artery (RCA). The maximum dose to the nontargeted major coronary arteries was determined and compared to similar data calculated for endovascular brachytherapy. RESULTS: High-precision EBRT targeted at LCx stents contributed a mean maximum dose (D(max)) of 83.5% (range: 71.6-95.3%) and 16.3% to the LAD and RCA, respectively. Targeted LAD stents contributed a mean D(max) of 39.3% (range: 14.5-94.8%) and 5.2% (range: 0-13.4%) to the LCx and RCA, respectively. Targeted RCA stents contributed a mean D(max) of 6.2% (range: 0-12.4%) and 5.8% (range: 0-11.5%) to the LCx and LAD, respectively. Endovascular brachytherapy targeted at LCx stents contributed a mean D(max) of 1.7% (range: 0.7-2.7%) and 1.0% (range: 0.6-1.4%) to the LAD and RCA, respectively. Targeted LAD stents contributed a mean D(max) of 5.2% (range: 0.5-11.4%) and 0.7% (range: 0.4-1.1%) to the LCx and RCA, respectively; targeted RCA stents contributed a mean D(max) of 0.3% (range: 0.2-0.5%) and 0.2% (range: 0.1-0.3%) to the LCx and LAD, respectively.CONCLUSIONS: Although the doses distributed throughout the heart were higher for high-precision EBRT compared to endovascular brachytherapy, they are expected to be clinically irrelevant when nontargeted major coronary arteries are not closely situated to the targeted vessel segment. These encouraging results warrant further investigation of high-precision EBRT as a potential alternative to endovascular brachytherapy for the treatment of coronary artery in-stent restenosis.