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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.

ObjectiveCardiovascular magnetic resonance imaging (CMR) has been established as a modality to detect myocardial viability. The aim of this study was to evaluate myocardial viability by observing transmural extent of infraction and microvascular perfusion level.MethodsWe performed CMR in 30 myocardial infarction (MI) patients within 7–10 days. At the 6‑month follow-up, CMR was used to evaluate the impact of abnormal reperfusion and observe the transmural extent of infraction on recovery of function.ResultsThe left ventricle was divided into 16 segments using the American Heart Association classification. Infarcts were detected in 202 of the 480 segments (42%) by delayed enhancement magnetic resonance imaging (DE-MRI). According to first-pass myocardial perfusion, abnormal perfusion was detected in 278 of 480 segments (60%), reduced perfusion was identified in 173 of 278 (62%), and perfusion defects in 105 of 278 segments (38%). The results showed that the segments with abnormal perfusion were larger than in DE-MRI (P < 0.05), indicating that the area of abnormal perfusion segments extend significantly beyond the region of infarction. Microvascular perfusion with an infarcted region was lower compared to non-infarcted segments (P < 0.05). The extent of myocardial hyperenhancement correlated inversely with microvascular perfusion (P < 0.05). Segments with severe microvascular perfusion and >75% transmural infarction on the 7‑ to 10-day scan had markedly increased at the 6‑month follow-up (P < 0.01), indicating a lack of recovery of cardiac function.ConclusionsDE-MRI combined with microvascular perfusion may be effective to detect viable myocardium in patients with MI and may provide a means of predicting whether revascularization will be effective.

Objectives In an elderly population, the prevalence of unrecognized myocardial infarction (UMI) scars found via late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) imaging was more frequent than expected. This study investigated whether UMI scars detected with LGE-CMR at age 70 would be detectable at age 75 and whether the scar size changed over time. Methods From 248 participants that underwent LGE-CMR at age 70, 185 subjects underwent a follow-up scan at age 75. A myocardial infarction (MI) scar was defined as late enhancement involving the subendocardium. Results In the 185 subjects that underwent follow-up, 42 subjects had a UMI scar at age 70 and 61 subjects had a UMI scar at age 75. Thirty-seven (88 %) of the 42 UMI scars seen at age 70 were seen in the same myocardial segment at age 75. The size of UMI scars did not differ between age 70 and 75. Conclusions The prevalence of UMI scars detected at LGE-CMR increases with age. During a 5-year follow-up, 88 % (37/42) of the UMI scars were visible in the same myocardial segment, reassuring that UMI scars are a consistent finding. The size of UMI scars detected during LGE-CMR did not change over time.

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 The impact of a cryoballoon ablation is reported to be similar to that of a radiofrequency (RF) ablation in patients with atrial fibrillation. Delayed enhancement magnetic resonance imaging (DE-MRI) could visualize the scar region induced by the cryoballoon ablation as well as RF ablation. Cryoballoon ablation could induce extensive scar lesions around the PVs. However, the distribution of the scar lesions after the cryoballoon ablation has not been well discussed. We, herein, described a case with an eccentric scar distribution after cryoballoon ablation.

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.

We report on cardiomyopathy in propionic acidemia (PA) diagnosed using delayed-enhancement cardiac magnetic imaging (DECM) in a 27-year-old woman. DECM demonstrated hyperenhancement at the lateral wall of the left ventricle, suggesting myocardial changes occurring after a metabolic crisis, which improved during the convalescent period. DECM was useful for the diagnosis of cardiomyopathy in PA.

A 73-year-old man presented with suspected acute myocardial infarction at the outpatient clinic. However, the clinical symptoms and the laboratory findings were not diagnostic. Only emergency cardiac magnetic resonance imaging (MRI) was helpful in making a definitive diagnosis of acute myocardial infarction. Cardiac MRI is a useful diagnostic tool for suspected acute coronary syndrome in emergency room settings when conventional modalities do not provide a definitive diagnosis.