Aortic Root Dilatation Measured by Cardiac Magnetic Resonance in Patients with Repaired Tetralogy of Fallot.

BACKGROUND: Aortic root dilatation (AoD) frequently occurs following repaired tetralogy of Fallot (rTOF). The objective of this study was to assess aortic dimensions, investigate the prevalence of AoD, and identify predictors of AoD in rTOF patients. METHODS: A cross-sectional retrospective study was conducted in repaired TOF patients from 2009 to 2020. Aortic root diameters were measured by cardiac magnetic resonance (CMR). Severe AoD of the aortic sinus (AoS) was defined as a Z-score (z) of >4, reflecting a mean percentile ≥99.99%. RESULTS: Two hundred forty-eight patients, with a median age of 28.2 years (10.2-65.3 years), were included in the study. The median age at the time of repair was 6.6 years (0.8-40.5 years) and the median interval between the repair and CMR study was 18.9 years (2.0-54.8 years). The prevalence of severe AoD was found to be 35.2% when defined by an AoS z greater than 4 and 27.6% when defined by a AoS diameter ≥40 mm, respectively. A total of 101 patients (40.7%) had aortic regurgitation (AR), with 7 patients (2.8%) having moderate AR. Multivariate analysis revealed that severe AoD was only associated with the left ventricular end diastolic volume index (LVEDVi) and a longer duration after repair. The age at the time of repair for TOF was found not to be correlated with the development of AoD. CONCLUSIONS: After repair of TOF, severe AoD was found to be prevalent, but no fatal complications were observed in our study. Mild AR was also commonly observed. Larger LVEDVi and a longer duration after repair were identified as factors associated with the development of severe AoD. Therefore, routine monitoring of AoD is recommended.

Dark-blood late gadolinium-enhancement cardiac magnetic resonance imaging for myocardial scar detection based on simplified timing scheme: single-center experience in patients with suspected coronary artery disease.

BACKGROUND: This study aims to examine scar detectability using dark-blood late gadolinium enhancement (LGE) with simplified timing scheme and fixed parameters comparing to two conventional bright-blood approaches in patients with known or suspected coronary artery disease. METHODS: Three LGE techniques were performed in all patients with known or suspected coronary artery disease at 3 T: dark blood two-dimensional (2D) phase-sensitive inversion recovery (PSIR) preceded with a T2-preparation pulse (DB-LGE), conventional three-dimensional (3D) gradient-echo inversion recovery (3D-IR) and conventional 2D PSIR. Timing parameters in DB-LGE were tested in five clinically confirmed coronary artery disease patients with scars and fixed for the rest of the study. Two independent readers evaluated images at both patient and segment levels. Image quality and contrast ratio between scar and adjacent tissues were assessed. Concordance between the three techniques and detection rate based on expert consensus were reported. RESULTS: Forty-six patients were recruited in the study (average age 66.8 years, 69.6% male). DB-LGE demonstrated superior image quality (P=0.001 vs. 3D-IR) and scar-to-blood contrast ratio (P<0.001 vs. 3D-IR and PSIR). Among 41 patients with suspected coronary artery disease, myocardial scar was present in 30 patients (73.2%), all detected by DB-LGE, yielding a detection rate of 100% compared to 93.3% and 96.7% for bright-blood 3D-IR and PSIR. For subendocardial scar detection among 656 segments, DB-LGE had a detection rate of 99.4% compared to 57.8% for 3D-IR and 61.0% for PSIR (both P<0.001). CONCLUSIONS: DB-LGE improves detection of myocardial scar compared with conventional bright-blood LGE techniques, particularly of subendocardial scar.

Prevalence and characters of anomalous coronary artery from coronary magnetic resonance angiography.

BACKGROUND: Many types of anomalous coronary artery have been reported. Some forms of the anomaly are potentially malignant and can lead to sudden death. OBJECTIVE: To determine the prevalence and characters of anomalous coronary artery, including the associations of myocardial ischemia. MATERIAL AND METHOD: This is a retrospective study. The authors enrolled patients who were referred for cardiac magnetic resonance (CMR) and had magnetic resonance coronary angiography (MRCA) images. Imaging of the coronary arteries was acquired. The presence and patterns of anomalous coronary artery and the presence of myocardial ischemia was recorded. Myocardial perfusion study was also performed in most patients using adenosine stress test. RESULTS: Anomalous coronary artery was detected in 56 out of 3,703 patients (1.51%). There were 24 men (42.9%). Average age was 62.1 +/- 15.0 years. Most common type was right coronary artery (RCA) from left coronary cusp. Malignant form was demonstrated in 31 patients (55.4%) and myocardial ischemia was detected in 10 patients (23.3%). CONCLUSION: Prevalence of anomalous coronary artery was 1.5%. Most common types were RCA from left coronary cusp (30%) and high take-off RCA (30%).

Prognostic value of late gadolinium enhancement in hypertensive patients with known or suspected coronary artery disease.

To determine the prognosis of a myocardial scar assessed by a late gadolinium enhancement (LGE) technique of cardiac magnetic resonance (CMR) in hypertensive patients with known or suspected coronary artery disease (CAD). Patients with systemic hypertension with known or suspected CAD without a clinical history of myocardial infarction were enrolled. All patients underwent CMR for assessment of cardiac function and LGE. Prognostic data was determined by the occurrence of a hard cardiac endpoint, defined as cardiac death or a non-fatal myocardial infarction, or major adverse cardiac events (MACEs), defined as cardiac death, a non-fatal myocardial infarction, or hospitalization due to heart failure, unstable angina, or life-threatening ventricular arrhythmia. A total of 1,644 patients were enrolled; 48% were males and the mean age was 65 +/- 11 years. The average follow-up time was 863 +/- 559 days. Four hundred fifty-three (28%) patients had LGE. LGE was the strongest and most independent predictor for hard events and MACEs with hazard ratios of 4.77 and 3.38, respectively. Other independent predictors of hard events and MACEs were left ventricular ejection fraction and mass, the use of a beta-blocker, and a history of heart failure. The risk of cardiac events increased as the extent of LGE increased; the hazard ratio was 12.74 for hard events for those with a LGE >20% of the myocardium. LGE is the most important and independent predictor for cardiac events in hypertensive patients with known or suspected CAD.

Prognostic significance of left ventricular mass by magnetic resonance imaging study in patients with known or suspected coronary artery disease.

OBJECTIVES: To study the prognostic value of left ventricular mass (LVM) assessed by cardiac magnetic resonance in patients with known or suspected coronary artery disease. METHODS: We studied patients who were referred for cardiac magnetic resonance for the assessment of cardiac function, LVM, and late gadolinium enhancement (LGE). Prognostic value was determined by the occurrence of hard cardiac endpoint, including death or nonfatal myocardial infarction and major adverse cardiac event, which also included hospitalization due to heart failure or unstable angina and life-threatening ventricular arrhythmia. We analyzed prognostic value of LVM index stratified by quintiles and specific percentile ranges. RESULTS: A total of 2194 patients with the average age of 65 +/- 11 years were enrolled. Average left ventricular ejection fraction and LVM index were 59.2 +/- 19.4% and 56.6 +/- 21.3 g/m(2), respectively. LGE was present in 785 patients (35.8%). Average follow-up duration was 926 +/- 582 days. Hard events and major adverse cardiac events occurred in 92 (4.2%) and 210 patients (9.6%). Cox regression analysis showed that left ventricular ejection fraction, LGE, and LVM index were independent predictors for clinical events. The highest quartile of LVM index had the greatest risk for clinical events independent of other factors, including left ventricular ejection fraction and LGE. CONCLUSION: LVM index by cardiac magnetic resonance is an independent predictor for cardiovascular event in patients with known or suspected coronary artery disease.

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 (> or =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.

Correlation Between NT-pro BNP levels and left ventricular wall stress, sphericity index and extent of myocardial damage: a magnetic resonance imaging study.

BACKGROUND: To determine the relationship between N-terminal pro-brain natriuretic peptide (NT-pro BNP) levels and left ventricular wall stress, sphericity index, function, and extent of myocardial damage in patients with coronary artery disease and abnormal left ventricular wall motion. METHODS AND RESULTS: All patients underwent cardiac magnetic resonance imaging (CMR). Measurements of sphericity index and wall stress were performed. Percentages of myocardial scarring were calculated from delayed-enhancement images. Correlations between log NT-pro BNP levels and various parameters were evaluated. There were 125 patients with an average age of 62.6 +/- 9.6 years. Median levels of NT-proBNP were 1012 pg/mL. Average left ventricular ejection fraction (LVEF) was 37 +/- 14.4%. Log NT-proBNP levels had positive correlations with wall stress, sphericity index, left ventricular dimension, volume, mass, wall motion score, extent of myocardial scarring, and age, and had negative correlations with creatinine clearance, LVEF, stroke volume, and body size. Multiple linear regression analysis showed that diastolic and systolic wall stress and systolic sphericity index were independent predictors for log NT-proBNP levels. CONCLUSIONS: NT-proBNP levels strongly correlated with left ventricular wall stress and moderately correlated with sphericity index.

Accuracy of visual assessment in the detection and quantification of myocardial scar by delayed enhancement magnetic resonance imaging.

BACKGROUND: Delayed-enhancement magnetic resonance imaging (DE-MRI) is now a standard for the detection of myocardial scar and viability. Standard analysis needs expensive software. OBJECTIVE: To determine the accuracy of visual assessment in the detection and quantification of myocardial scar by DE-MRI technique. MATERIAL AND METHOD: The authors enrolled 32 patients with coronary artery disease (CAD) as documented by coronary angiography (CAG) and left ventricular dysfunction. All patients underwent cardiac magnetic resonance imaging for the assessment of global and regional myocardial function and DE-MRI. The presence and amount of scar in each myocardial segment was assessed by standard method. Visual assessment was performed by two methods: 1) visual drawing of the boundary of the hyperenhancement region and calculation of percentages of scar in an individual segment; 2) visual estimation of grading of hyperenhancement area from 0 (no scar) to 4 (> 75% scar). The agreement for scar detection and correlation of scar quantification for individual segments were evaluated. RESULTS: Thirty-one of 32 patients in the present study had myocardial scar. One thousand four hundred and thirty two myocardial segments were analyzed. Visual detection of myocardial scar has an excellent level of agreement with standard method of scar (Kappa = 0.963 and 0.952, p<0.001 for visual method I and II). Visual method I and II has an accuracy of 98.2% and 97.6% respectively in the detection of myocardial scar compared to standard method. Percentages of myocardial scar in each myocardial segment by visual method I correlate very well with standard method (Intraclass Correlation Coefficient = 0.885). Visual grading of amount of myocardial scar also has an excellent correlation with standard method (Spearman rank correlation coefficient = 0.934). CONCLUSION: Visual assessment of myocardial scar is accurate for the detection and quantification of scar.

Magnetic resonance imaging abnormalities in right ventricular outflow tract tachycardia and the prediction of radiofrequency ablation outcome.

BACKGROUND: Recent reports have shown abnormalities on cardiac magnetic resonance imaging (MRI) in patients with right ventricular outflow tract (RVOT) tachycardia. OBJECTIVES: OBJECTIVES of this study were to demonstrate abnormalities on MRI and signal-averaged ECG (SAECG) in patients with RVOT tachycardia and their correlation with the outcome of radiofrequency (RF) ablation. METHODS: We studied 41 patients with symptomatic RVOT tachycardia and 15 controls. SAECG and cardiac MRI were performed on every subject. An evaluation of structural abnormality, chamber size, function, and wall motion abnormality of the left and right ventricle was performed by MRI. Focal wall thinning was evaluated by the black blood technique and fatty infiltration was evaluated by the T1 image with and without fat suppression. RESULTS: MRI abnormalities were demonstrated in 24 (58.5%) patients with RVOT tachycardia. The abnormalities included localized wall bulging in 22 (53.7%), focal wall thinning in 10 (24.4%), and fatty replacement in 9 (22%) patients. MRI abnormality was found in only one patient in the control group (P < 0.001). Late potentials from SAECG were demonstrated in six (10.7%) patients but none in the controls (P = 0.117). Among 29 patients who underwent RF ablation, 3 patients had a failed procedure and 3 having arrhythmia recurrence needed repeated ablation. MRI abnormalities and late potentials were associated with an unfavorable outcome of RF ablation. CONCLUSIONS: MRI abnormalities were frequently found in patients with RVOT tachycardia. MRI abnormalities and late potentials can predict outcomes of RF ablation.

Accuracy of magnetic resonance imaging in the diagnosis of coronary artery disease.

BACKGROUND: Coronary magnetic resonance angiography is a noninvasive method to visualize coronary arteries. The objective of this study was to determine the accuracy of coronary magnetic resonance imaging in the detection of coronary artery stenosis. METHOD: The authors studied 61 patients who were scheduled for their first diagnostic X-ray coronary angiography. Magnetic resonance imaging of the coronary arteries under free-breathing was performed prior to the catheterization schedule. The results were compared. RESULTS: Forty-one out of 61 patients (67.2%) had significant coronary stenosis of at least one major coronary artery. Sixteen (26.2%) had triple vessel disease. A total of 391 of 427 segments had interpretable image quality (91.6%). The diagnostic accuracy of the left main artery, left anterior descending artery, left circumflex artery, and right coronary artery was 96.7 per cent, 90 per cent, 80 per cent and 85.2 per cent respectively. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of the detection of any significant coronary disease were 97.6 per cent, 75 per cent, 91.2 per cent, 90.9 per cent and 92.3 per cent respectively. CONCLUSIONS: Coronary magnetic resonance imaging is an accurate non-invasive imaging technique in the detection of coronary artery stenosis.