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.

Native T1 mapping and extracellular volume fraction for differentiation of myocardial diseases from normal CMR controls in routine clinical practice.

BACKGROUND: This study aimed to determine native T1 and extracellular volume fraction (ECV) in distinct types of myocardial disease, including amyloidosis, dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), myocarditis and coronary artery disease (CAD), compared to controls. METHODS: We retrospectively enrolled patients with distinct types of myocardial disease, CAD patients, and control group (no known heart disease and negative CMR study) who underwent 3.0 Tesla CMR with routine T1 mapping. The region of interest (ROI) was drawn in the myocardium of the mid left ventricular (LV) short axis slice and at the interventricular septum of mid LV slice. ECV was calculated by actual hematocrit (Hct) and synthetic Hct. T1 mapping and ECV was compared between myocardial disease and controls, and between CAD and controls. Diagnostic yield and cut-off values were assessed. RESULTS: A total of 1188 patients were enrolled. The average T1 values in the control group were 1304 ± 42 ms at septum, and 1294 ± 37 ms at mid LV slice. The average T1 values in patients with myocardial disease and CAD were significantly higher than in controls (1441 ± 72, 1349 ± 59, 1345 ± 59, 1355 ± 56, and 1328 ± 54 ms for septum of amyloidosis, DCM, HCM, myocarditis, and CAD). Native T1 of the mid LV level and ECV at septum and mid LV with actual and synthetic Hct of patients with myocardial disease or CAD were significantly higher than in controls. CONCLUSIONS: Although native T1 and ECV of patients with cardiomyopathy and CAD were significantly higher than controls, the values overlapped. The greatest clinical utilization was found for the amyloidosis group.

Clinical assessment of adenosine stress and rest cardiac magnetic resonance T1 mapping for detecting ischemic and infarcted myocardium.

Cardiac magnetic resonance (CMR) spin-lattice relaxation time (T1) may be influenced by pathologic conditions due to changes in myocardial water content. We aimed to validate the principle and investigate T1 mapping at rest and adenosine stress to differentiate ischemic and infarcted myocardium from controls. Patients with suspected coronary artery disease who underwent CMR were prospectively recruited. Native rest and adenosine stress T1 maps were obtained using standard modified Look-Locker Inversion-Recovery technique. Among 181 patients included, T1 values were measured from three groups. In the control group, 72 patients showed myocardium with a T1 profile of 1,039 ± 75 ms at rest and a significant increase during stress (4.79 ± 3.14%, p < 0.001). While the ischemic (51 patients) and infarcted (58 patients) groups showed elevated resting T1 compared to controls (1,040 ± 90 ms for ischemic; 1,239 ± 121 ms for infarcted, p < 0.001), neither of which presented significant T1 reactivity (1.38 ± 3.02% for ischemic; 1.55 ± 5.25% for infarcted). We concluded that adenosine stress and rest T1 mapping may be useful to differentiate normal, ischemic and infarcted myocardium.

Detection of cardiac iron overload with native magnetic resonance T1 and T2 mapping in patients with thalassemia.

BACKGROUND: To investigate the diagnostic performance of native cardiac magnetic resonance (CMR) T1 and T2 mapping for cardiac iron overload (CIO) in thalassemia patients. METHODS: All thalassemia patients who underwent CMR were enrolled on a clinical 1.5T scanner. Native T1 mapping with the Modified Look-Locker Inversion recovery (MOLLI) technique, T2 mapping using a black-blood multi-echo spin-echo technique, and conventional T2* mapping using multi-echo gradient-echo techniques were performed. CIO was defined by a T2* of <20ms; while severe CIO was considered as <10ms. RESULTS: A total of 200 patients were enrolled in the study (23.9±14.6years old [mean±SD], 102 male). Among these, 8 patients (4.0%) had CIO. Both native T1 and T2 times were significant different among patients with no CIO, mild-to-moderate CIO, and severe CIO (1012.7±57.7 vs. 846.4±34.4 vs 601.3±34.6ms for T1, p<0.05; 59.6±6.5 vs. 48.7±2.5 vs. 32.8±1.2ms for T2, p<0.05). The best cut-off values for detection of CIO were 887 and 52ms for T1 and T2, respectively. This yielded a sensitivity, specificity and area under the curve (AUC) of 100%, 98.4% and 0.997 respectively for T1, in comparison to 100%, 88.8% and 0.961 respectively for T2. CONCLUSIONS: Native T1 mapping can differentiate between severe, mild-to-moderate, and no CIO, which appears to be a promising technique for detection and assessment of myocardial iron.

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.