Utility of stress perfusion-cardiac magnetic resonance in follow-up of patients undergoing percutaneous coronary interventions of the left main coronary artery

To assess the accuracy of cardiac magnetic resonance (CMR) for the diagnosis of angiographic stenosis after percutaneous coronary intervention (PCI) of left main coronary artery (LMCA). Patients undergone in the last year PCI of unprotected LMCA and scheduled for conventional X-ray coronary angiography (CXA) were evaluated with stress perfusion CMR within 2 weeks before CXA. Main contraindications to CMR were exclusion criteria. Stress perfusion CMR was performed to follow a bolus of contrast Gadobutrol after 3 min of adenosine infusion. Between the 50 patients enrolled, only 1 did not finish the CMR protocol and 49 patients with median age 71 (65–75) years (38 male, 11 female) were analyzed. Between 784 coronary angiographic segments evaluated we found 75 stenosis or occlusions (prevalence 9.5%), but only 13 stenosis or occlusions in proximal segments (prevalence 6.6%). Patients with coronary stenosis (n?=?12, 24%) showed a significantly (p?=?0.002) higher prevalence of diabetes (7 of 12, 58%). At CMR examination, late gadolinium enhancement was present in 25 (51%), reversible perfusion defects in 12 (24%), and fixed perfusion defects in 6 subjects (12%). The only patient with LMCA restenosis resulted positive at perfusion CMR. The accuracy of stress perfusion CMR in diagnosis of coronary stenosis was higher when the analysis was performed only in proximal coronary arteries (95%, CI 86–99) compared to overall vessels (84%, CI 70–92). Stress perfusion CMR could strongly reduce the need for elective CXA in follow up of LMCA PCI and should be validated in further multicenter prospective studies.     

Fusion of CT coronary angiography and whole-heart dynamic 3D cardiac MR perfusion: building a framework for comprehensive cardiac imaging

The purpose of this work was to develop a framework for 3D fusion of CT coronary angiography (CTCA) and whole-heart dynamic 3D cardiac magnetic resonance perfusion (3D-CMR-Perf) image data—correlating coronary artery stenoses to stress-induced myocardial perfusion deficits for the assessment of coronary artery disease (CAD). Twenty-three patients who underwent CTCA and 3D-CMR-Perf for various indications were included retrospectively. For CTCA, image quality and coronary diameter stenoses >?50% were documented. For 3D-CMR-Perf, image quality and stress-induced perfusion deficits were noted. A software framework was developed to allow for 3D image fusion of both datasets. Computation steps included: (1) fully automated segmentation of coronary arteries and heart contours from CT; (2) manual segmentation of the left ventricle in 3D-CMR-Perf images; (3) semi-automatic co-registration of CT/CMR datasets; (4) projection of the 3D-CMR-Perf values on the CT left ventricle. 3D fusion analysis was compared to separate inspection of CTCA and 3D-CMR-Perf data. CT and CMR scans resulted in an image quality being rated as good to excellent (mean scores 3.5?±?0.5 and 3.7?±?0.4, respectively, scale 1–4). 3D-fusion was feasible in all 23 patients, and perfusion deficits could be correlated to culprit coronary lesions in all but one case (22/23?=?96%). Compared to separate analysis of CT and CMR data, coronary supply territories of 3D-CMR-Perf perfusion deficits were refined in two cases (2/23?=?9%), and the relevance of stenoses in CTCA was re-judged in four cases (4/23?=?17%). In conclusion, 3D fusion of CTCA/3D-CMR-Perf facilitates anatomic correlation of coronary lesions and stress-induced myocardial perfusion deficits thereby helping to refine diagnostic assessment of CAD.     

Clinical implication of adenosine-stress cardiac magnetic resonance imaging as potential gatekeeper prior to invasive examination in patients with AHA/ACC class II indication for coronary angiography

BACKGROUND : Real world cardiology is faced with a low diagnostic yield of coronary angiography (CXA) in patients presenting with ACC/AHA class II CXA indication. Our aim was to analyze the clinical implication of a Cardiac MR (CMR) protocol including adenosine stress perfusion in this patient population. We examined whether CMR could enhance appropriate CXA indication and thus reduce the rate of pure diagnostic CXA. In addition, we compared the relative impact of CMR exam components (perfusion, function and viability assessment) in achieving this target. METHODS : 176 patients were referred for CXA with class II indication. 171 underwent complete additional CMR exam in a 1.5-T whole body CMR-scanner for myocardial function, ischemia and viability prior to CXA. The routine protocol for assessment of CAD consisted of functional imaging (long and short axes), adenosine stress- and rest-perfusion in short axis orientation and "late enhancement" imaging in long and short axes. Images were analyzed by two independent and blinded investigators. Interobserver differences were resolved by a third reader. RESULTS : There was a high association between CMR results and subsequent invasive findings (chi square for CMR perfusion deficit and stenosis >70% in CXA: 113.7, p<0.0001). 109 (63.7%) of our patients had relevant perfusion deficits as seen by CMR and matching coronary artery stenosis >70%. Four (2.3%) patients had false negative CMR findings. In 58 patients (33.9%) no relevant coronary artery stenosis could be observed, correctly predicted by CMR in 48 cases; in 10 (5.8%) patients CMR provided false positive results. Sensitivity of CMR to detect relevant CAD (>70% luminal narrowing) was 0.96, specificity 0.83, positive predictive value 0.92 and negative predictive value 0.92. Of the CMR components, perfusion deficit was the strongest independent predictor (odds ratio 132.3, p < 0.0001). CONCLUSION : In a great number of patients being referred to cath lab with ACC/AHA class II indication for CXA, CMR provides a high accuracy for decision making regarding appropriateness of the invasive exam. CMR prior to CXA could substantially reduce pure diagnostic coronary angiographies in patients with intermediate probability for CAD, in our patient-cohort from approximately 34% to 6%. Further studies are warranted to identify rare false negative CMR results.     

Combining cardiac magnetic resonance and computed tomography coronary calcium scoring: added value for the assessment of morphological coronary disease?

To investigate prospectively, in patients with suspicion of coronary artery disease (CAD), the added value of coronary calcium scoring (CS) as adjunct to cardiac magnetic resonance (CMR) for the diagnosis of morphological coronary stenosis in comparison to catheter angiography (CA). Sixty consecutive patients (8 women; 64 ± 10 years) referred to CA underwent CMR (1.5 T) including perfusion and late gadolinium-enhancement imaging as well as CS with computed tomography. Diagnostic performance was evaluated for CMR and CS separately, and for both methods combined, with CA as reference standard. Best CS threshold combined with a specificity >90% to predict significant stenosis in patients without abnormalities on CMR was determined from receiver operator characteristics (ROC) analysis. Abnormal CMR results were considered to indicate significant stenosis regardless of CS; CS above threshold reclassified patients to have CAD regardless of CMR. CA identified 104/960 (11%) coronary segments with coronary artery stenosis >50% in 36/60 (60%) patients. ROC revealed an area-under-the-curve of 0.83 (95%CI: 0.68-0.99) with the best CS threshold of 495 Agatston score (sensitivity 50%). CMR depicted 128/960 (13%) myocardial segments with abnormalities in 31/60 (52%) patients. Sensitivity, specificity, negative (NPV) and positive predictive value (PPV) of CMR were 78, 88, 72 and 90%. When adding CS to CMR, sensitivity and NPV increased to 89 and 83%, while specificity and PPV slightly decreased to 83 and 89%. Accuracy of the combined approach (87%) was significantly (P < 0.05) higher than that of CMR (82%) alone. Adding CS to CMR improves the accuracy for the detection of morphological CAD.     

The prominent role of cardiac magnetic resonance imaging in coronary artery disease

The role of cardiac magnetic resonance (CMR) in coronary artery disease is prominent. CMR provides functional and structural heart disease assessment with high accuracy. It allows accurate cardiac volume and flow quantification and wall motion analysis both at rest and at stress. CMR myocardial perfusion studies detect myocardial ischemia and provide insights into the morphology of the myocardial tissue. CMR imaging noninvasively differentiates causes of myocardial injury such as ischemia or inflammation; stages of myocardial injury, such as acute or chronic; grade of myocardial damage, such as reversible or irreversible; myocardial fibrosis or scar. There is an emerging role of CMR in patients with acute chest presentation since it can demonstrate causes of chest pain other than coronary artery disease such as myocarditis, pericarditis, aortic dissection and pulmonary embolism. CMR is noninvasive and radiation-free. It’s combined approach of functional and structural cardiac assessment makes it unique compared with other imaging modalities.     

Assessment of coronary artery disease with a combined magnetic resonance examination

Cardiovascular magnetic resonance (CMR) imaging provides morphological and functional data relevant to the assessment of coronary artery disease (CAD). A wide range of such data can be acquired in a single multiparametric imaging session. In stable CAD, a combined CMR examination comprising assessment of cardiac function, perfusion, and myocardial viability can be used to detect the presence of CAD and to determine the appropriateness of coronary revascularization. In acute coronary syndromes, a combined CMR examination can be used for the differential diagnosis of myocarditis and other acute cardiac disease, for risk-stratification of patients after myocardial infarction and for the targeted assessment of complications of myocardial infarction. This article overviews the CMR methods that are available for assessment of CAD and describes situations when combined CMR examinations can play a role in its diagnosis and differential diagnosis.     

Incidental renal artery stenosis among a prospective cohort of hypertensive patients undergoing coronary angiography

OBJECTIVE: To determine the feasibility, safety, and clinical yield of angiographic screening among hypertensive patients undergoing coronary angiography. PATIENTS AND METHODS: This study was a prospective cohort analysis of hypertensive patients who underwent cardiac catheterization at a tertiary care referral center from July 1998 to March 1999. Abdominal aortography was performed to screen for renal artery stenosis, the percentage of which was measured. RESULTS: The mean +/- SD age of the 297 study patients was 64.9+/-10.2 years; 58.6% were male, and 98.0% were white. Mean +/- SD systolic/diastolic blood pressure was 142.8+/-22.5/79.6+/-11.4 mm Hg. Aortography required a mean incremental dose of 62+/-9 mL of nonionic contrast agent. No complications were attributable to aortography. Of 680 renal arteries, 611 (90%) were visualized adequately. Also, 53% of patients had normal renal arteries, 28% had stenoses less than 50%, and 19.2% had stenoses of 50% or more. Renal artery stenosis was bilateral in 3.7% of patients and high grade (>70% stenosis) in 7%. Patients with renal artery stenosis were more likely to have had a previous coronary intervention. In multivariate analysis, systolic blood pressure (odds ratio [OR], 1.2; 95% confidence interval [CI], 1.03-138; P=.02), history of stroke or transient ischemic attack (OR, 2.7; 95% CI, 1.27-5.78; P=.01), and cancer (OR, 2.0; 95% CI, 1.02-3.82; P=.04) independently correlated with renal artery stenosis of 50% or more. CONCLUSION: The prevalence of incidental renal artery stenosis among hypertensive patients undergoing coronary catheterization is significant. Therefore, screening abdominal aortography should be considered in these patients to better define their risk of cardiovascular complications.     

Myocardial perfusion cardiac magnetic resonance for the diagnosis of coronary artery disease: do we need rest images?

Adenosine stress cardiovascular magnetic resonance (CMR) has been reported to be useful for the diagnosis of coronary artery disease (CAD). Most studies use rest and stress perfusion images. The objectives of this study were to determine (Barkhausen et al. in J Magn Reson Imaging 19(6):750–757, 1) the accuracy of visual assessment and myocardial perfusion reserve index (MPRI) in the diagnosis of CAD and (Rieber et al. in Fur Heart J 27(12):1465–1471, 2) the accuracy of analysis based on rest–stress and stress images. We enrolled patients with suspected CAD and referred them for coronary angiography (CAG). All the patients underwent adenosine stress CMR before CAG. Rest and stress perfusion images were analyzed by calculation of MPRI and visual assessment separately. Visual assessment was performed separately by using rest and stress images and by using only stress images. CAG was considered the gold standard. Sensitivity, specificity, and accuracy of both methods were calculated and compared. A total of 66 patients (mean age, 61.3 ± 11.7 years) were studied. Thirty-eight patients (57.6%) were diagnosed with CAD. The sensitivity and specificity for the diagnosis of CAD (≥50% stenosis) were 89.5 and 78.6% for MPRI, 76.3 and 75% for stress–rest visual method, and 86.8 and 75% for stress visual method, respectively. CMR perfusion had a relatively lower accuracy in patients with left ventricular systolic dysfunction, high left ventricular mass, or presence of late gadolinium enhancement than in patients without those CMR findings. Visual assessment of stress image of CMR perfusion is accurate and comparable to MPRI for the detection of CAD.     

Transesophageal echocardiography in the diagnosis of ostial left coronary artery stenosis

The diagnosis of ostial stenosis of the left main coronary artery is usually made by use of coronary angiography. However, positioning of the catheter across the obstruction may obscure this diagnosis during contrast injection. Although a damping of arterial pressure when the catheter enters the left coronary artery may suggest ostial stenosis, it may not be possible to make this diagnosis with certainty during cardiac catheterization. We report a series of four patients in whom the left coronary ostium and proximal left coronary arteries were visualized by means of transesophageal echocardiography. Both ostial narrowing by plaque and abnormally fast flow velocities were seen. In each case the echocardiographic findings contributed to the subsequent management of the patients.     

Visual assessment of coronary artery stenosis with electrocardiographically-gated multislice computed tomography

BACKGROUND: With faster image acquisition times and thinner slice widths, multislice detector computed tomography (MSCT) allows visualization of human coronary arteries. Significantly improved image quality, with high resolution and new software for three-dimensional post-processing, has made noninvasive examination of the cavities within human body possible. OBJECTIVE: The aims of this study are to evaluate the diagnostic accuracy of ECG-gated MSCT for the detection of significant coronary artery stenosis and occlusions. METHODS: In 25 patients (19 male and 6 female aged 65+/-9 years) with suspected obstructive coronary artery disease, ECG-gated MSCT angiography was performed with an 8-slice MSCT scanner. Visual coronary arteries were simulated in three coronary arteries. Conventional coronary angiographies were performed in all patients. And coronary lesions in MSCT were estimated by two observers, who did not know the results of the coronary angiography. RESULTS: Current MSCT allows visual coronary artery with good image quality. The overall sensitivity for diagnosing significant coronary stenosis were 75.0%, the specificity was 95.6%. The positive and negative predictive values were 84.9 and 92.2%, respectively. The accuracy of MSCT for detecting coronary stenosis is the highest in the left main tranck and left anterior descending coronary artery, and lowest in the circumflex coronary artery. CONCLUSION: MSCT was feasible for the detection of coronary artery stenosis.     

Cardiovascular magnetic resonance findings in repaired anomalous left coronary artery to pulmonary artery connection (ALCAPA)

Background

Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare coronary artery anomaly. This study shows the role of cardiovascular magnetic resonance (CMR) in assessing young patients following surgical repair of ALCAPA.

Methods

6 patients, aged 9-21 years, with repaired ALCAPA (2 Tackeuchi method, 4 direct re-implantation) underwent CMR because of clinical suspicion of myocardial ischemia. Imaging used short and long axis cine images (assess ventricular function), late-gadolinium enhancement (LGE) (detect segmental myocardial fibrosis), adenosine stress perfusion (detect reversible ischaemia) and 3D whole-heart imaging (visualize proximal coronary arteries).

Results

The left ventricular (LV) global systolic function was preserved in all patients (mean LV ejection fraction = 62.7% ± 4.23%). The LV volumes were within the normal ranges, (mean indexed LVEDV = 75.4 ± 3.5 ml/m², LVESV = 31.6 ± 9.4 ml/m²). In 1 patient, hypokinesia of the anterior segments was visualized. Five patients showed sub-endocardial LGE involving the basal, antero-lateral wall and the anterior papillary muscle. Three patients had areas of reversible ischemia. In these 3, 3D whole-heart MRA showed that the proximal course of the left coronary artery was occluded (confirmed with cardiac catheterisation).

Conclusions

CMR is a good, non-invasive, radiation-free investigation in the post-surgical evaluation of ALCAPA. In referred patients we show that basal, antero-lateral sub-endocardial myocardial fibrosis is a characteristic finding. Furthermore, stress adenosine CMR perfusion, can identify reversible ischemia in this group, and was indicative of left coronary artery occlusion.     

64层螺旋CT冠状动脉成像质量及对冠状动脉疾病的诊断价值 （附562例应用体会）

目的：评价64层螺旋CT冠状动脉成像（64SCTCA）在诊断冠状动脉疾病中的临床价值。方法：收集562例临床可疑冠心病患者SCTCA的完整资料，其中48例与近期选择性X线冠状动脉成像（CCA）结果进行了对照分析，并对64层SCTCA显示的冠状动脉主干及主要分支情况进行了分级评估。结果：562例患者中有48例经CCA证实，48例720个节段中有687个节段可做定量评价，SCTCA发现98个节段有狭窄，CCA发现92个节段有狭窄，SCTCA诊断狭窄的敏感性为94.5%，特异性为98.1%，阳性预测值为88.7%，阴性预测值为99.2%。结论：64SCTCA对于冠状动脉狭窄的评估具有较高敏感性和特异性，适用于冠心病的筛查，具有重要的临床价值。     

Angiographic correlations of patients with small vessel disease diagnosed by adenosine-stress cardiac magnetic resonance imaging

Cardiac magnetic resonance imaging (CMR) with adenosine-stress myocardial perfusion is gaining importance for the detection and quantification of coronary artery disease (CAD). However, there is little knowledge about patients with CMR-detected ischemia, but having no relevant stenosis as seen on coronary angiography (CA). The aims of our study were to characterize these patients by CMR and CA and evaluate correlations and potential reasons for the ischemic findings. 73 patients with an indication for CA were first scanned on a 1.5T whole-body CMR-scanner including adenosine-stress first-pass perfusion. The images were analyzed by two independent investigators for myocardial perfusion which was classified as subendocardial ischemia (n = 22), no perfusion deficit (n = 27, control 1), or more than subendocardial ischemia (n = 24, control 2). All patients underwent CA, and a highly significant correlation between the classification of CMR perfusion deficit and the degree of coronary luminal narrowing was found. For quantification of coronary blood flow, corrected Thrombolysis in Myocardial Infarction (TIMI) frame count (TFC) was evaluated for the left anterior descending (LAD), circumflex (LCX) and right coronary artery (RCA). The main result was that corrected TFC in all coronaries was significantly increased in study patients compared to both control 1 and to control 2 patients. Study patients had hypertension or diabetes more often than control 1 patients. In conclusion, patients with CMR detected subendocardial ischemia have prolonged coronary blood flow. In connection with normal resting flow values in CAD, this supports the hypothesis of underlying coronary microvascular impairment. CMR stress perfusion differentiates non-invasively between this entity and relevant CAD.     

Low-dose CT and cardiac MR for the diagnosis of coronary artery disease: accuracy of single and combined approaches

To prospectively compare the diagnostic performance of low-dose computed tomography coronary angiography (CTCA) and cardiac magnetic resonance imaging (CMR) and combinations thereof for the diagnosis of significant coronary stenoses. Forty-three consecutive patients with known or suspected coronary artery disease underwent catheter coronary angiography (CA), dual-source CTCA with prospective electrocardiography-gating, and cardiac CMR (1.5 Tesla). The following tests were analyzed: (1) low-dose CTCA, (2) adenosine stress-rest perfusion-CMR, (3) late gadolinium enhancement (LGE), (4) perfusion-CMR and LGE, (5) low-dose CTCA combined with perfusion-CMR, (5) low-dose CTCA combined with late gadolinium-enhancement, (6) low-dose CTCA combined with perfusion-CMR and LGE. CA served as the standard of reference. CA revealed >50% diameter stenoses in 68/129 (57.7%) coronary arteries in 29/43 (70%) patients. In the patient-based analysis, sensitivity, specificity, NPV and PPV of low-dose CTCA for the detection of significant stenoses were 100, 92.9, 100 and 96.7%, respectively. For perfusion-CMR and LGE, sensitivity, specificity, NPV, PPV, and accuracy were 89.7, 100, 82.4, and 100%, respectively. In the artery-based analysis, sensitivity and NPV of low-dose CTCA was significantly (P < 0.05) higher than that of perfusion-CMR and LGE. All combinations of low-dose CTCA and perfusion-CMR and/or LGE did not improve the diagnostic performance when compared to low-dose CTCA alone. Taking CA as standard of reference, low-dose CTCA outperforms CMR with regard to sensitivity and NPV, whereas CMR is more specific and has a higher PPV than low-dose CTCA.     

Myocardial perfusion reserve assessed by t2-prepared steady-state free precession blood oxygen level-dependent magnetic resonance imaging in comparison to fractional flow reserve

Background- Blood oxygen level-dependent (BOLD) cardiac magnetic resonance imaging (CMR) has been shown to be able to detect myocardial perfusion differences. However, validation of BOLD CMR against fractional flow reserve (FFR) is lacking. The aim of our study was to analyze the potential diagnostic accuracy of BOLD CMR in comparison to invasively measured FFR, which served as gold standard for a hemodynamic significant coronary lesion. Methods and Results- BOLD image was performed at rest and during adenosine infusion in a 1.5-T CMR scanner. Thirty-six patients were analyzed for relative BOLD signal intensity increase according to the 16-segment model. Invasive FFR measurements were performed in the 3 major coronary arteries during adenosine infusion in all patients. An FFR≤0.8 was regarded to indicate a significant coronary lesion. Relative BOLD signal intensity increase was significantly lower in myocardial segments supplied by coronary arteries with an FFR≤0.8 compared with segments with an FFR>0.8 (1.1±0.2 versus 1.5±0.2; P<0.0001). Sensitivity and specificity yielded 88.2% and 89.5%, respectively. Conclusions- CMR BOLD imaging reliably detects hemodynamic significant coronary artery disease and is, thus, an alternative to contrast-enhanced perfusion studies.     

Cardiovascular magnetic resonance of pulmonary artery growth and ventricular function after Norwood procedure with Sano modification

For hypoplastic left heart syndrome (HLHS), there have been concerns regarding pulmonary artery growth and ventricular dysfunction after first stage surgery consisting of the Norwood procedure modified with a right ventricle-to-pulmonary artery conduit. We report our experience using cardiovascular magnetic resonance (CMR) to determine and follow pulmonary arterial growth and ventricular function in this cohort.Following first stage palliation, serial CMR was performed at 1 and 10 weeks post-operatively, followed by cardiac catheterization at 4 – 6 months. Thirty-four of 47 consecutive patients with HLHS (or its variations) underwent first stage palliation. Serial CMR was performed in 20 patients. Between studies, ejection fraction decreased (58 ± 9% vs. 50 ± 5%, p < 0.05). Pulmonary artery growth occurred on the left (6 ± 1 mm vs. 4 ± 1 mm at baseline, p < 0.05) but not significantly in the right. This trend continued to cardiac catheterization 4–6 months post surgery, with the left pulmonary artery of greater size than the right (8.8 ± 2.2 mm vs. 6.7 +/- 1.9 mm, p < 0.05). By CMR, 5 had pulmonary artery stenoses initially, and at 2 months, 9 had stenoses. Three of the 9 underwent percutaneous intervention prior to the second stage procedure.In this cohort, reasonable growth of pulmonary arteries occurred following first stage palliation with this modification, although that growth was preferential to the left. Serial studies demonstrate worsening of ventricular function for the cohort. CMR was instrumental for detecting pulmonary artery stenosis and right ventricular dysfunction.     

Myocardial perfusion cardiac magnetic resonance for the diagnosis of coronary artery disease: do we need rest images?

Adenosine stress cardiovascular magnetic resonance (CMR) has been reported to be useful for the diagnosis of coronary artery disease (CAD). Most studies use rest and stress perfusion images. The objectives of this study were to determine (Barkhausen et al. in J Magn Reson Imaging 19(6):750–757, 1) the accuracy of visual assessment and myocardial perfusion reserve index (MPRI) in the diagnosis of CAD and (Rieber et al. in Fur Heart J 27(12):1465–1471, 2) the accuracy of analysis based on rest–stress and stress images. We enrolled patients with suspected CAD and referred them for coronary angiography (CAG). All the patients underwent adenosine stress CMR before CAG. Rest and stress perfusion images were analyzed by calculation of MPRI and visual assessment separately. Visual assessment was performed separately by using rest and stress images and by using only stress images. CAG was considered the gold standard. Sensitivity, specificity, and accuracy of both methods were calculated and compared. A total of 66 patients (mean age, 61.3 ± 11.7 years) were studied. Thirty-eight patients (57.6%) were diagnosed with CAD. The sensitivity and specificity for the diagnosis of CAD (≥50% stenosis) were 89.5 and 78.6% for MPRI, 76.3 and 75% for stress–rest visual method, and 86.8 and 75% for stress visual method, respectively. CMR perfusion had a relatively lower accuracy in patients with left ventricular systolic dysfunction, high left ventricular mass, or presence of late gadolinium enhancement than in patients without those CMR findings. Visual assessment of stress image of CMR perfusion is accurate and comparable to MPRI for the detection of CAD.     

Head-to-head comparison of first-pass MR perfusion imaging during adenosine and high-dose dobutamine/atropine stress

To directly compare the stressor capabilities of adenosine and high-dose dobutamine/atropine using first pass myocardial perfusion magnetic resonance imaging. Fourty-one patients with suspected or known coronary artery disease underwent cardiac magnetic resonance (CMR) perfusion imaging at 1.5 Tesla on two consecutive days prior to invasive coronary angiography. On day 1 a standard CMR perfusion protocol during adenosine stress was carried out (adenosine infusion with 140 μg/kg/min, 0.1 mmol/kg Gd-DTPA). On day 2, the identical CMR perfusion sequence was repeated during a standard high-dose dobutamine/atropine stress protocol at rest and during target heart rate (85% of maximum age-predicted heart rate). Stress-inducible perfusion deficits were evaluated visually regarding presence and transmural extent. Quantitative coronary angiography served as the reference standard with significant stenosis defined as ≥50% luminal diameter reduction. Twenty-five patients (61%) had significant coronary stenoses. Adenosine and dobutamine stress CMR perfusion imaging resulted in an equally high sensitivity and specificity for the stenosis detection on a per patient basis (92 and 75% for both stressors, respectively). Agreement of both stressors with regard to the presence or absence of stress-inducible perfusion deficits was nearly perfect using patient- and segment based analysis (kappa 1.0 and 0.92, respectively). Adenosine and dobutamine/atropine stress CMR perfusion imaging are equally capable to identify stress inducible deficits and resulted in an almost identical extent of ischemic reactions. Though adenosine stress CMR perfusion imaging is widely employed, dobutamine stress CMR perfusion represents a valid alternative and may be particularly useful in patients with contraindications to vasodilator testing.     

Noninvasive detection of coronary allograft vasculopathy by myocardial contrast echocardiography.

BACKGROUND: Noninvasive detection of coronary allograft vasculopathy is still challenging. To determine the accuracy of myocardial contrast echocardiography (MCE) in detecting coronary allograft vasculopathy after heart transplantation, we studied 35 asymptomatic patients (30 men, aged 46 +/- 12.7 years) with normal left ventricular function. METHODS: Patients underwent MCE with continuous contrast (perfluorocarbon-exposed sonicated dextrose albumin) administration. Images were obtained at baseline and during peak dobutamine (up to 40 mg/kg/min) with intermittent harmonic imaging. Areas failing to increase contrast enhancement during peak stress were regarded as abnormal. Coronary artery obstructions greater than 50% at angiography were considered significant. RESULTS: Seven out of 10 patients with coronary artery disease had a positive MCE and one patient with a positive MCE had no angiographically detected disease (sensitivity = 70%, specificity = 96%, accuracy = 88.6%). Agreement between the vascular territory and perfusion defects was good for the left anterior descending coronary artery (kappa = 0.56), but not for other arteries. Although 5 patients had multivessel disease, multiple perfusion defects were detected in only one patient. CONCLUSION: MCE showed good accuracy in detecting the presence of coronary allograft vasculopathy after heart transplantation; however, it failed to identify the extent of the disease.     

Quantification of myocardial perfusion reserve at 1.5 and 3.0 Tesla: a comparison to fractional flow reserve

The objective of this study was to compare quantitative analysis of cardiac magnetic resonance (CMR) perfusion at 1.5 and 3 T against fractional flow reserve (FFR) as measured invasively. FFR is considered by many investigators to be a reliable standard to determine hemodynamically significant coronary artery stenoses. Quantitative 1.5 and 3 T CMR is capable to noninvasively determine myocardial perfusion reserve, but have not been compared against each other and validated against FFR as standard reference. Patients with suspected or known coronary artery disease (CAD) underwent CMR at at both field strengths, 1.5 and 3 T, and FFR. 34 patients were included into the study. Quantitative myocardial perfusion reserve was calculated in 544 myocardial segments at 1.5 and 3 T, respectively. FFR was measured in 109 coronary arteries. FFR ≤ 0.8 was regarded relevant. Reduced FFR (≤0.8) was found in 38 coronary arteries (19 LAD, 8 LCX and 11 RCA). Receiver operator curve analysis yielded higher area under the curve for 3 T CMR in comparison to 1.5 T CMR (0.963 vs. 0.645, p < 0.001) resulting in higher sensitivity (90.5 vs. 61.9 %) and specificity (100 vs. 76.9 %). Quantitative analysis of CMR myocardial perfusion reserve at 1.5 and 3 T is capable to detect hemodynamic significance of coronary artery stenoses. Diagnostic accuracy at 3 T is to be superior to 1.5 T.