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This study proposes machine learning-based models to automatically evaluate the severity of myocardial infarction (MI) from physiological, clinical, and paraclinical features. Two types of machine learning models are investigated for the MI assessment: the classification models classify the presence of the infarct and the persistent microvascular obstruction (PMO), and the regression models quantify the Percentage of Infarcted Myocardium (PIM) of patients suspected of having an acute MI during their reception in the emergency department. The ground truth labels for these supervised models are derived from the corresponding Delayed Enhancement MRI (DE-MRI) exams and manual annotations of the myocardium and scar tissues. Experiments were conducted on 150 cases and evaluated with cross-validation. Results showed that for the MI (PMO inclusive) and the PMO (infarct exclusive), the best models obtained respectively a mean error of 0.056 and 0.012 for the quantification, and 88.67 and 77.33% for the classification accuracy of the state of the myocardium. The study of the features' importance also revealed that the troponin value had the strongest correlation to the severity of the MI among the 12 selected features. For the proposal's translational perspective, in cardiac emergencies, qualitative and quantitative analysis can be obtained prior to the achievement of MRI by relying only on conventional tests and patient features, thus, providing an objective reference for further treatment by physicians.

Abstract Background Atrial tissue fibrosis has previously been identified using delayed-enhancement MRI (DE-MRI) in patients with atrial fibrillation (AF). Although the clinical importance of DE-MRI is well recognized, the visualization of atrial fibrosis and radiofrequency (RF) lesions has still not been achieved in Japan, primarily because of the differences in contrast agents, volume-rendering tools, and technical experience. The objective of this study was to visualize RF lesions by using commercially available tools. Methods DE-MRI was performed in 15 patients who had undergone AF ablation (age, 59±4 years, left atrium diameter, 40±2 mm). Specific parameters for MR scanning obtained from previous reports were modified. Results Of the 15 images, the images of three patients were uninterpretable owing to low image quality. RF lesions could be visualized in 8 (67%) of the 12 patients. Conclusions In the current study, we successfully demonstrated that RF lesions could be visualized in Japanese patients using DE-MRI, although only commercially available tools were used.

Abstract Background The radiofrequency (RF) lesions for atrial fibrillation (AF) ablation can be visualized by delayed enhancement magnetic resonance imaging (DE-MRI). However, the quality of anatomical information provided by DE-MRI is not adequate due to its spatial resolution. In contrast, magnetic resonance angiography (MRA) provides similar information regarding the left atrium (LA) and pulmonary veins (PVs) as computed tomography angiography. We hypothesized that DE-MRI fused with MRA will compensate for the inadequate image quality provided by DE-MRI. Methods DE-MRI and MRA were performed in 18 patients who underwent AF ablation (age, 60±9 years; LA diameter, 42±6 mm). Two observers independently assessed the DE-MRI and DE-MRI fused with MRA for visualization of the RF lesion (score 0–2; where 0: not visualized and 2: excellent in all 14 segments of the circular RF lesion). Results DE-MRI fused with MRA was successfully performed in all patients. The image quality score was significantly higher in DE-MRI fused with MRA compared to DE-MRI alone (observer 1: 22 (18, 25) vs 28 (28, 28), p <0.001; observer 2: 24 (23, 25) vs 28 (28, 28), p <0.001). Conclusions DE-MRI fused with MRA was superior to DE-MRI for visualization of the RF lesion owing to the precise information on LA and PV anatomy provided by DE-MRI.

Objective: To test the hypothesis that myocardial scars are common in patients with systemic right ventricles. Methods: 27 consecutive patients with systemic right ventricle were studied with delayed-enhancement magnetic resonance imaging and positron emission tomography. Of the 27 patients, 18 had had an atrial switch operation a mean of 21.8 (SD 4.5) years previously and were 23.4 (SD 5.3) years old. Nine patients without previous heart surgery had congenitally corrected transposition of the great arteries and were 35.3 (SD 15.6) years old. Results: Only one patient had a subendocardial scar identified by delayed-enhancement magnetic resonance imaging. Positron emission tomography identified no myocardial scars. Conclusions: This study shows that the hypothesis that myocardial scars are common in patients with systemic right ventricles is not correct.

Abstract Background There is increasing interest in performing left atrial appendage (LAA) occlusion at the time of atrial fibrillation (AF) ablation procedures. However, to date there has been no description of the acute changes to the LAA immediately following pulmonary vein (PV) isolation and additional left atrium (LA) substrate modification. This study assessed changes in the size and tissue characteristics of the LAA ostium in patients undergoing PV isolation. Methods This series included 8 patients who underwent cardiovascular magnetic resonance evaluation of the LA with delayed enhancement magnetic resonance imaging and contrast enhanced 3-D magnetic resonance angiography pre-, within 48 h of, and 3 months post ablation. Two independent cardiac radiologists evaluated the ostial LAA diameters and area at each time point in addition to the presence of gadolinium enhancement. Results Compared to pre-ablation values, the respective median differences in oblique diameters and LAA area were +1.8 mm, +1.7 mm, and +0.6 cm2 immediately post ablation (all NS) and −2.7 mm, −2.3 mm, and −0.5 cm2 at 3 months (all NS). No delayed enhancement was detected in the LAA post ablation. Conclusion No significant change to LAA diameter, area, or tissue characteristics was noted after PV isolation. While these findings suggest the safety and feasibility of concomitant PV isolation and LAA device occlusion, the variability in the degree and direction of change of the LAA measurements highlights the need for further study.

Hospitals are a critical component of the health care provided to many Brazilians.Hospitals--which absorb nearly 70 percent of public spending on health--are also a critical component of the government's budget, and are thus at the forefront of policy discussions.Why hospitals are important in Brazil is easy to understand.

Now in its Second Edition, this resident-friendly reference explains the basics of MRI...then walks readers easily through the radiologic evaluation of shoulder disorders, particularly rotator cuff disease and shoulder instability. Written in an inviting, easy-to-follow style and illustrated with more than 600 scans, this long-awaited new edition will be a favorite practical reference for residents, practicing radiologists, and orthopaedic surgeons. The book features contributions from expert radiologists and orthopaedic surgeons. Chapters review MRI techniques and shoulder anatomy, describe and illustrate MRI findings for a wide variety of conditions, and explain how abnormalities seen on MR images relate to pathophysiology and clinical signs.