Search

Background: To estimate median liver iron concentration (LIC) calculated from magnetic resonance imaging, excluded vessels of the liver parenchyma region were defined manually. Previous works proposed the automated method for excluding vessels from the liver region. However, only user-defined liver region remained a manual process. Therefore, this work aimed to develop an automated liver region segmentation technique to automate the whole process of median LIC calculation., Methods: 553 MR examinations from 471 thalassemia major patients were used in this study. LIC maps (in mg/g dry weight) were calculated and used as the input of segmentation procedures. Anatomical landmark data were detected and used to restrict ROI. After that, the liver region was segmented using fuzzy c-means clustering and reduced segmentation errors by morphological processes. According to the clinical application, erosion with a suitable size of the structuring element was applied to reduce the segmented liver region to avoid uncertainty around the edge of the liver. The segmentation results were evaluated by comparing with manual segmentation performed by a board-certified radiologist., Results: The proposed method was able to produce a good grade output in approximately 81% of all data. Approximately 11% of all data required an easy modification step. The rest of the output, approximately 8%, was an unsuccessful grade and required manual intervention by a user. For the evaluation matrices, percent dice similarity coefficient (%DSC) was in the range 86-92, percent Jaccard index (%JC) was 78-86, and Hausdorff distance (H) was 14-28 mm, respectively. In this study, percent false positive (%FP) and percent false negative (%FN) were applied to evaluate under- and over-segmentation that other evaluation matrices could not handle. The average of operation times could be reduced from 10 s per case using traditional method, to 1.5 s per case using our proposed method., Conclusion: The experimental results showed that the proposed method provided an effective automated liver segmentation technique, which can be applied clinically for automated median LIC calculation in thalassemia major patients., (© 2021. The Author(s).)

Background: Presence of left ventricular hypertrophy (LVH) increases the risk for cardiovascular event. Many electrocardiographic (ECG) criteria can be used to diagnose LVH; however, high body mass index (BMI) may reduce ECG amplitudes.The aim of this study was to investigate the diagnostic performance of ECG criteria for diagnosing LVH among various BMI groups compared to diagnosis by cardiac magnetic resonance (CMR) imaging., Methods: Patients who were referred for CMR were enrolled. CMR and ECG were performed on the same day. Left ventricular function, volume, and mass were calculated from CMR. Standard ECG criteria were measured, including: Cornell voltage, Cornell product, Romhilt-Estes point score system, Sokolow-Lyon index, and Sokolow-Lyon-Rappaport index. Diagnostic performance of each ECG criterion was calculated and analyzed in the following four BMI groups: underweight (<18.5 kg/m 2 ), normal (18.5-22.9 kg/m 2 ), overweight (23-24.9 kg/m 2 ), and obese (≥25 kg/m 2 )., Results: Of the 1,882 patients that were included, 67 were underweight, 459 were normal weight, 434 were overweight, and 922 were obese. LVH was diagnosed in 34 (50.7%) underweight, 144 (31.4%) normal weight, 100 (23.0%) overweight, and 181 (19.6%) obese patients. Overall specificity of ECG was high (0.89-0.95), and overall sensitivity was low (0.25-0.37). The specificity of each ECG criterion was similar among BMI groups; however, the sensitivity of ECG criteria demonstrated a decreasing trend in the higher BMI groups., Conclusion: All ECG criteria demonstrated relatively high specificity and relatively low sensitivity. Although the specificity across groups remained similar, higher BMI was found to be associated with decreased sensitivity., (© 2019 Wiley Periodicals, Inc.)

Background: Coronary heart disease requires advanced investigations. However, findings of fundamental investigations are sometimes underused and/or neglected, such as plain chest X-ray (CXR) and electrocardiography (ECG). A previous study found an association between aortic calcification and coronary artery disease, but there are no studies that have investigated association between aortic arch calcification in CXR and coronary artery disease consequences, such as myocardial viability (scarring)., Objective: To investigated association between aortic arch calcification detected on plain CXR and myocardial scarring detected on cardiac magnetic resonance imaging (CMRI) in coronary heart disease patients., Material and Method: one hundred eighty-seven eligible patients aged ≥18 years and diagnosed as coronary heart disease by CMRI at Siriraj Hospital between January 2008 and December 2014 study periods were enrolled. We retrospectively reviewed aortic arch calcification from plain CXR, demographic data, hospitalization data, underlying disease, medications used, and CMRI parameters., Results: There was no significant association between aortic arch calcification from CXR and myocardial scar by CMRI. Aortic arch calcification was detected in 86 (45.98%) and 78 (41.70%) of patients with and without myocardial scar by CMRI (p = 0.981). There was no significant correlation between calcium grading and calcium thickness from CXR and the presence or absence of myocardial scar by CMRI. Myocardial scar was detected in 52.2%, 47.8%, 51.4%, and 59.1% in patients with calcium grade 0, 1, 2, and 3 respectively (p = 0.751)., Conclusion: There was no association found between aortic arch calcification detected on plain CXR and myocardial scarring detected on CMRI.

Background: In thalassemia patients, R2* liver iron concentration (LIC) measurement is a common clinical tool for assessing iron overload and for determining necessary chelator dose and evaluating its efficacy. Despite the importance of accurate LIC measurement, existing methods suffer from LIC variability, especially at the severe iron overload range due to inclusion of vessel parts in LIC calculation. In this study, we build upon previous Fuzzy C-Mean (FCM) clustering work to formulate a scheme with superior performance in segmenting vessel pixels from the parenchyma. Our method (MIX-FCM) combines our novel 2D-FCM with the existing 1D-FCM algorithm. This study further assessed possible optimal clustering parameters (OP scheme) and proposed a semi-automatic (SA) scheme for routine clinical application., Methods: Segmentation of liver parenchyma and vessels was performed on T2* images and their LIC maps in 196 studies from 147 thalassemia major patients. We used manual segmentation as the reference. 1D-FCM clustering was performed on the acquired image alone and 2D-FCM used both the acquired image and its LIC data. To execute the MIX-FCM method, the best outcome (OP-MIX-FCM) was selected from the aforementioned methods and was compared to the SA-MIX-FCM scheme. We used the percent value of the normalized interquartile range (nIQR) to its median to evaluate the variability of all methods., Results: 2D-FCM clustering is more effective than 1D-FCM clustering at the severe overload range only, but inferior for other ranges (where 1D-FCM provides suitable results). This complementary performance between the two methods allows MIX-FCM to improve results for all ranges. OP-MIX-FCM clustering error was 2.1 ± 2.3%, compared with 10.3 ± 9.9% and 7.0 ± 11.9% from 1D- and 2D-FCM clustering, respectively. SA-MIX-FCM result was comparable to OP-MIX-FCM result, with both schemes showing ability to decrease overall nIQR by approximately 30%., Conclusion: Our proposed 2D-FCM algorithm is not as superior to 1D-FCM as hypothesized. In contrast, our MIX-FCM method benefits from the best of both methods to obtain the highest segmentation accuracy at all ranges. Moreover, segmentation accuracy of the practical scheme (SA-MIX-FCM) is comparable to segmentation accuracy of the reference scheme (OP-MIX-FCM). Finally, we confirmed that segmentation is crucial to improving LIC assessments, especially at the severe iron overload range.

Background: Acute changes in high-sensitivity troponin T (hs-TnT) are induced by myocardial ischemia during exercise stress testing, but there are no reports of pharmacological stress testing., Hypothesis: The pattern of troponin release by myocardial ischemia-induced pharmacological stress testing differs according to the ischemic burden in stable patients., Methods: In total, 250 patients with suspected coronary artery disease underwent pharmacological stress magnetic resonance imaging (MRI). The amount and degree of myocardial ischemia on MRI and ischemic outcomes at 6 months were determined. hs-TnT levels were measured at baseline and 1 and 3 hours after testing. The 6-month clinical outcome was prespecified., Results: Fifty-one patients had moderate to severe myocardial ischemia (group A), and 199 patients had no or mild myocardial ischemia (group B). hs-TnT levels were significantly higher in group A than B at baseline (11 vs 8 pg/mL, P = 0.016) and at 1 hour (12 vs 8 pg/mL, P = 0.009) and 3 hours after testing (12 vs 9 pg/mL, P = 0.012). Baseline hs-TnT levels of ≥14 pg/mL showed a 43% sensitivity and 77% specificity in predicting moderate to severe ischemia by MRI (P = 0.03; area under the curve: 0.608, P = 0.017). Patients administered dobutamine had a higher acute change in hs-TnT levels 3 hours after testing than did those administered adenosine (21 vs 0 pg/mL, P < 0.001). There was a trend toward a higher incidence of myocardial infarction in patients with baseline hs-TnT levels of ≥14 pg/mL., Conclusions: hs-TnT levels are significantly higher in patients with moderate to severe than no or mild myocardial ischemia., (© 2015 Wiley Periodicals, Inc.)

Background: There are many ECG criteria for the diagnosis of left ventricular hypertrophy (LVH). There are, however limited data on the accuracy of these criteria in comparison with cardiac magnetic resonance (CMR)., Objective: To determine the accuracy of ECG criteria for the diagnosis of LVH using CMR as the gold standard and to assess gender-specific data., Material and Method: Patients who were referred for CMR for clinical purposes were studied. ECG and CMR were performed on the same day. Functional CMR protocol was performed for the assessment of cardiac volume, function and mass. CMR variables were indexed by the adjustment of body surface area. The following ECG criteria were used: Romhilt-Estes criteria (score at least 4 or 5 points were used in the present study), Sokolow-Lyon and Sokolow-Lyon-Rappaport, Cornell voltage and Cornell product, and sum of QRS voltage of all 12 leads. CMR of 184 subjects (120females, 64 males) free of cardiovascular disease was used as controls. Patients with left ventricular mass index above 95 percentile of gender specific left ventricular mass in control group were considered LVH. Diagnostic yield of ECG criteria for LVH was calculated for the whole group and each gender, Results: There were a total of 1,882 patients, 994 males and 888 females. Average age was 64.6 +/- 11.3 years. LVH was diagnosed by CMR in 23.3% in female and 25.4% in male. ECG criteria for the diagnosis of LVH had a relatively low sensitivity (0.25-0.61), and high specificity (0.75-0.95). Female had a lower sensitivity, higher specificity, higher PPV similar NPV and higher overall accuracy than male. Cornell product, Romhilt-Estes (at least 4 points) and Sokolow-Lyon were the ECG criteria with the best accuracy, sensitivity and specificity, respectively., Conclusion: ECG criteria for the diagnosis of LVH had a relatively low sensitivity, and high specificity. The accuracy was in the range of 0.71-0.80. Cornell product had the highest accuracy.

Objective: To compare inter-site observer variability of the Pixel- Wise (PW) method for cardiac T2* analysis in thalassemia patients using the mono-exponential with a constant fitting (offset) model and to compare the cross-model variability of the offset model to the mono-exponential (typical) model., Material and Method: Eighty-eight cardiac T2* measurements were performed on 72 Thalassemia major patients. Both bright- and black-blood techniques were acquired and analyzed at both the reference (REF) and local (LOC) sites using the PW method by defined region of interest on the whole (at the REF site) and partial (at the LOC site) septum. The offset model was analyzed at the reference site while both the offset and typical models were performed at the local site. The inter-site variability of the T2* values were analyzed by independent observers blinded to the results., Results: The T2* values from the REF-offset, LOC-offset and LOC-typical methods were statistically comparable on both scanning techniques. The inter-site variations of the offset model were about 5.2% and 4.4% on the bright- and black-blood techniques, respectively, which was about 1.7% higher than from the intra-site, but was still in a reasonable range compared to the conventional method of around 5.4%. The cross-model comparisons presented with 0.4 ms of bias and variation of about 6.9% and 4.7%, respectively, which is about 1.4% higher than from the intra-site., Conclusion: The observer variability on the PW method using the offset or typical model provided equivalent coefficient of variation on both scanning techniques, which was also comparable to the previous reports. The inter-site variability of the offset and cross models was also in a reasonable range, being less than 2% higher than the intra-site with bias of about 0.4 ms.

Late gadolinium enhancement (LGE) and myocardial perfusion study by cardiac magnetic resonance (CMR) have a diagnostic and prognostic value in patients with suspected coronary artery disease (CAD). The purpose of this study was to determine the prognostic value of combined myocardial perfusion CMR and LGE in patients with known or suspected CAD. We studied patients with known or suspected CAD. All patients underwent CMR for functional study, myocardial perfusion and LGE. Myocardial ischemia by CMR was defined as a perfusion defect in patients without LGE or a perfusion defect beyond the LGE area. Patients were followed up for cardiovascular outcomes including hard cardiac events (cardiac death or non-fatal myocardial infarction) and major adverse cardiac events (MACE) which included cardiac death, non-fatal myocardial infarction, hospitalization for unstable angina, and heart failure. There were a total of 587 men and 645 women. Average age was 64.6 ± 11.1 years. LGE was detected in 326 patients (26.5%). Myocardial ischemia by CMR was detected in 423 patients (34.3%). Average follow-up duration was 34.9 ± 15.6 months. Univariate analysis showed that age, diabetes, use of beta blocker, left ventricular ejection fraction, left ventricular mass, wall motion abnormality, LGE, and myocardial ischemia are predictors for hard cardiac events and MACE. Multivariable analysis revealed that myocardial ischemia was the strongest predictor for hard cardiac events and MACE. Other independent predictors were age, use of beta blocker, and left ventricular mass. Myocardial ischemia by CMR has an incremental prognostic value for cardiac events in patients with known or suspected CAD.

Purpose: To compare the observer variability of the conventional region-based (RB) to the typical and proposed pixel-wise (PW) methods for cardiac T2* analysis in thalassemia patients., Design and Methods: Fifty thalassemia major patients were enrolled for the study. Short-axis bright- and black-blood sequences were acquired and analyzed using the RB and PW methods. Regions were defined using the whole septum (WS) or partial septum (PS). From the same PS region, results were reported by mean (PS-PW) and median (MPS-PW). Intraobserver and interobserver variabilities were investigated on all data set by 2 independent observers blinded to the result., Results: The T2* values from the PS-PW and MPS-PW methods were comparable to the conventional WS-RB method on both scanning techniques. When comparing the interobserver variability from the WS-RB to the PS-PW method, the coefficient of variation of the PS-PW method was equivalent (4.5% vs 4.7%, P = NS) for the bright-blood technique but 31% lower (4.0% vs 2.8%, P = 0.21) for the black-blood technique. The proposed MPS-PW method performed even better with respect to the conventional WS-RB method, decreasing interobserver coefficient of variation by 24% (4.5% vs 3.5%, P = 0.08) and 42% (4.0% vs 2.4%, P = 0.02), respectively. Intraobserver reproducibility followed the same trend., Conclusions: The proposed PW method using the median of T2* values calculated from partial interventricular septum region provided lower intraobserver and interobserver variabilities compared with the conventional RB or typical PW methods.

Background: Diagnosis of coronary artery disease in patients with heart failure with systolic dysfunction usually requires coronary angiography. Cardiac magnetic resonance (CMR) is an accurate tool for the assessment of myocardial scar which may be the major cause of left ventricular systolic dysfunction., Objective: This study was to determine the prevalence and the difference in pattern of late gadolinium enhancement (LGE) between patients with ischemic (ICM) and non-ischemic cardiomyopathy (NICM)., Material and Method: We enrolled 98 patients with heart failure and left ventricular systolic dysfunction with left ventricular ejection fraction less than 50%. Allpatients underwent CMR. CMR protocol included functional study and assessment of LGE. Left ventricular volume and ejection fraction was measured. The presence and extent of LGE including its pattern were assessed., Results: There were 58 patients with ICM and 40 patients with NICM. Patients with NICM had a lower left ventricular ejection fraction than those with ICM with a similar left ventricular wall thickness. LGE was detected in 53 patients with ICM (91.5%) and 10 patients with NICM (25%). LGE pattern was transmural or subendocardial pattern in patients with ICM and midwall scar in those with NICM., Conclusion: The presence and pattern ofLGE can differentiate systolic heart failure from ICM and NICM.

Background: Some patients may have normal wall motion after myocardial infarction. The aim of this study was to determine the prevalence and prognosis of patients with myocardial scar in the absence of abnormal wall motion. We studied patients with suspected or known coronary artery disease (CAD) who were referred for cardiovascular magnetic resonance (CMR) for the assessment of global and regional cardiac function and late gadolinium enhancement (LGE) and had normal left ventricular wall motion. Prognostic value was determined by the occurrence of hard endpoints (cardiac death and nonfatal myocardial infarction) and major adverse cardiac events (MACE) which also included hospitalization due to unstable angina or heart failure or life threatening ventricular arrhythmia., Results: A total 1148 patients (70.3%) were studied. LGE was detected in 104 patients (9.1%). Prevalence of LGE increased in patients with increased left ventricular mass. Average follow-up time was 955 ± 542 days. LGE was the strongest predictor for hard endpoints and MACE., Conclusion: LGE was detected in 9.1% of patients with suspected or known CAD and normal wall motion. LGE was the strongest predictor of significant cardiac events.

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.

The ONgoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial (ONTARGET) showed that the angiotensin receptor blocker telmisartan 80 mg was not inferior to the angiotensin-converting enzyme inhibitor ramipril 10 mg, and the combination no more effective than ramipril alone, in decreasing morbidity and mortality in patients with cardiovascular disease or high-risk diabetes. Although therapy targeting angiotensin II is known to decrease left ventricular (LV) mass and volume, the relative influence of angiotensin-converting enzyme inhibitor inhibitors and angiotensin receptor blocker, and their combination, on the heart remains unclear in this population. Magnetic resonance imaging was performed in 287 patients enrolled in ONTARGET, across 8 centers in 6 countries, at randomization and after 2-year treatment (90, 100, and 97 patients in the ramipril, telmisartan, and combination therapy groups, respectively). Baseline patient characteristics showed higher frequencies of coronary artery disease, Asian ethnicity, and use of statins and beta blockers than the main ONTARGET trial. LV mass decreased in all groups (p <0.0001 for each), but there were no significant differences in change in LV mass or volume among groups, except that LV mass index decreased more on combination versus telmisartan (p = 0.04). Key determinants of LV mass decrease were a history of hypertension (p = 0.03), baseline mass (p <0.0001), and decrease in systolic blood pressure (p <0.0001). The best magnetic resonance imaging predictor of composite events was end-systolic volume (p <0.0001). In conclusion, telmisartan and ramipril had similar effects on LV mass and volume, and combination therapy was not more effective, in high-risk patients with cardiovascular disease. These results are consistent with the major outcome findings of the main ONTARGET study.

Background: The ONTARGET and TRANSCEND clinical trials were designed to investigate the cardioprotective effects of telmisartan 80 mg and ramipril 10 mg, alone and in combination, in patients at high risk of cardiovascular disease. Cardiac MRI enables investigation of mechanistic effects of these agents on cardiac structural and functional variables. Here, we report the design, analysis protocol, reproducibility and relevant quality control procedures, and baseline patient characteristics of the ONTARGET/TRANSCEND cardiac MRI substudy. MRI was undertaken in 330 subjects enrolled in ONTARGET, and 38 subjects in TRANSCEND, across eight centers in six countries. Analyses were performed by two independent analysts using guide-point modeling. Cases with discrepancies in LV mass (LVM) of >5% were independently reanalyzed. Cases with discrepancies in end-diastolic volume (EDV) of >5%, or end-systolic volume (ESV) of >12%, were then reconciled by consensus., Results: Baseline characteristics were broadly similar to the main ONTARGET/TRANSCEND trials, except for a higher frequency of coronary artery disease and Asian ethnicity in the substudy. Reproducibility of MRI analyses (mean +/- SD) were 2.8 +/- 3.7 ml in EDV, -0.3 +/- 3.6 ml in ESV, 3.1 +/- 3.3 ml in SV, 1.1 +/- 1.8% in EF, and 0.4 +/- 4.5 g in LVM. Subgroup analyses revealed increased ESV and LVM, and reduced EF, in subjects with a history of either coronary artery disease or myocardial infarction., Conclusions: The ONTARGET/TRANSCEND cardiac MRI substudy protocol provides for a reliable assessment of the effects of telmisartan and ramipril, alone and in combination, on cardiac structural and functional parameters over a 2-year follow-up period.

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.

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.

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.

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.

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.

The article examines accuracy of serum ferritin in the diagnosis of iron overload compared to use of magnetic resonance imaging in patients with thalassaemia. The patients wer referred for MRI examination for review of cardiac iron overload (CIO) and liver iron overload in various participating centers in Thailand.

Prevalence of cardiac and liver iron overload in patients with thalassemia in real-world practice may vary among different regions especially in the era of widely-used iron chelation therapy. The aim of this study was to determine the prevalence of cardiac and liver iron overload in and the management patterns of patients with thalassemia in real-world practice in Thailand. We established a multicenter registry for patients with thalassemia who underwent magnetic resonance imaging (MRI) as part of their clinical evaluation. All enrolled patients underwent cardiac and liver MRI for assessment of iron overload. There were a total of 405 patients enrolled in this study. The mean age of patients was 18.8 ± 12.5 years and 46.7% were male. Two hundred ninety-six (73.1%) of patients received regular blood transfusion. Prevalence of cardiac iron overload (CIO) and liver iron overload (LIO) was 5.2% and 56.8%, respectively. Independent predictors for iron overload from laboratory information were serum ferritin and transaminase for both CIO and LIO. Serum ferritin can be used as a screening tool to rule-out CIO and to diagnose LIO. Iron chelation therapy was given in 74.6%; 15.3% as a combination therapy. [ABSTRACT FROM AUTHOR]

Objective: Accurate assessment of the right ventricle (RV) is essential in patients with repaired tetralogy of Fallot (TOF). We proposed a simple echocardiographic method to assess the RV dimensions and evaluated the relationship between linear echocardiographic measures of the RV and RV volumes obtained by cardiovascular magnetic resonance imaging (CMR). Methods: A total of 45 patients (27.4 ± 11.2 years; 40% male) with repaired TOF underwent CMR and echocardiography. Using echocardiography, RV dimensions were assessed from the parasternal short-axis view using the longest RV internal diameter perpendicular to the mid-interventricular septum. Significant RV dilatation was defined as an RV end-diastolic volume index >160 mL/m2 on CMR. Results: There were significant correlations between RV dimensions determined by echocardiography and the pulmonary regurgitation fraction, RV size, and function determined by CMR. The cutoff values of echocardiographic RV outflow tract (RVOT), end-systolic and end-diastolic dimension indices, and the combination of RVOT and end-diastolic dimension indices to determine significant RV dilatation were 19.0, 19.4, 24.5, and 45.2 mm/m2, respectively. The positive and negative predictive values for significant RV dilatation were 89.7% and 68.8% with RVOT diameter index ≥19.0 mm/m2, 85.0% and 52.4% with RV end-systolic dimension index ≥19.4 mm/m2, 87.5% and 64.7% with RV end-diastolic dimension index ≥24.5 mm/m2, and 92.3% and 80.0% with the combination of RVOT and end-diastolic dimension indices ≥45.2 mm/m2, respectively. Conclusion: Echocardiography can be used to assess RV size in patients with repaired TOF with acceptable correlations with CMR as the reference standard. [ABSTRACT FROM AUTHOR]