Worldwide variation in cardiovascular magnetic resonance practice models.

INTRODUCTION: The use of cardiovascular magnetic resonance (CMR) for diagnosis and management of a broad range of cardiac and vascular conditions has quickly expanded worldwide. It is essential to understand how CMR is utilized in different regions around the world and the potential practice differences between high-volume and low-volume centers. METHODS: CMR practitioners and developers from around the world were electronically surveyed by the Society for Cardiovascular Magnetic Resonance (SCMR) twice, requesting data from 2017. Both surveys were carefully merged, and the data were curated professionally by a data expert using cross-references in key questions and the specific media access control IP address. According to the United Nations classification, responses were analyzed by region and country and interpreted in the context of practice volumes and demography. RESULTS: From 70 countries and regions, 1092 individual responses were included. CMR was performed more often in academic (695/1014, 69%) and hospital settings (522/606, 86%), with adult cardiologists being the primary referring providers (680/818, 83%). Evaluation of cardiomyopathy was the top indication in high-volume and low-volume centers (p = 0.06). High-volume centers were significantly more likely to list evaluation of ischemic heart disease (e.g., stress CMR) as a primary indicator compared to low-volume centers (p < 0.001), while viability assessment was more commonly listed as a primary referral reason in low-volume centers (p = 0.001). Both developed and developing countries noted cost and competing technologies as top barriers to CMR growth. Access to scanners was listed as the most common barrier in developed countries (30% of responders), while lack of training (22% of responders) was the most common barrier in developing countries. CONCLUSION: This is the most extensive global assessment of CMR practice to date and provides insights from different regions worldwide. We identified CMR as heavily hospital-based, with referral volumes driven primarily by adult cardiology. Indications for CMR utilization varied by center volume. Efforts to improve the adoption and utilization of CMR should include growth beyond the traditional academic, hospital-based location and an emphasis on cardiomyopathy and viability assessment in community centers.

Myocardial perfusion reserve quantified by cardiac magnetic resonance imaging is associated with late gadolinium enhancement in hypertrophic cardiomyopathy.

Late gadolinium enhancement (LGE) with cardiac magnetic resonance (CMR) imaging has demonstrated the capability of stratifying hypertrophic cardiomyopathy (HCM). Stress perfusion test of CMR can quantify myocardial perfusion reserve (MPR), but its clinical role is not determined. The purpose of this study was to investigate the relationship between MPR and LGE in patients with HCM. A total of 61 consecutive cases underwent complete evaluation with electrocardiography and CMR [cine imaging, coronary MR angiography (MRA), and stress perfusion testing with LGE]. HCM cases were diagnosed by the Japanese conventional guideline prior to this CMR study. Mild LVH was defined as more than 13 mm in maximum LV wall thickness at end diastole on the cine imaging of the CMR. MPR was calculated as the ratio of stress/rest myocardial blood flow using an intensity curve on the stress perfusion test. Cases with ischemic heart disease were excluded from the study based on clinical history and coronary MRA. There were 37 HCM and 24 mild LVH cases (average age: 60.5 ± 10.9 vs. 64.8 ± 10.8; male: 62.2 vs. 75.0%, respectively, non-significant). MPR in HCM was lower than in LVH (1.5 ± 0.5 vs. 2.2 ± 0.9, p < 0.001) and normal subjects (2.4 ± 0.9, p < 0.001). MPR in HCM with LGE (N = 34) was lower than in HCM without LGE (N = 3) (1.4 ± 0.5 vs. 2.1 ± 0.2, p = 0.014). Multiple regression analysis verified that LGE was the strongest predictor of MPR among multiple clinical parameters, including LVH, LV dysfunction (ejection fraction < 50%), and the presence of negative T wave (p < 0.001). MPR was impaired in HCM with LGE compared with HCM without LGE. The clinical role of MPR on CMR needs to be clarified by further research.

Luseogliflozin reduces epicardial fat accumulation in patients with type 2 diabetes: a pilot study.

BACKGROUND: Accumulation of epicardial fat (EF) is associated with increased cardio-metabolic risks and coronary events, independently of traditional cardiovascular risk factors. Therefore, the reduction of EF volume (EFV) may be associated with reduced cardio-metabolic risks and future cardiovascular events. Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce body fat including visceral fat and cardiovascular events in patients with type 2 diabetes. However, it has still been unknown whether SGLT2 inhibitors can reduce EFV. METHODS: Type 2 diabetic patients with HbA1c 6.5-9.0% and body mass index (BMI, kg/m2) ≥25.0 were enrolled in this single arm pilot study. Participants were administered luseogliflozin 2.5 mg daily and the dosage was tolerated to be increased up to 5.0 mg daily. EFV [median (interquartile range), cm3] was measured by magnetic resonance imaging. Primary endpoint was the decrease in EFV at 12 weeks. Visceral fat area (VFA, cm2) and liver attenuation index (LAI) measured by the abdominal computed tomography, and skeletal muscle index (SMI) and body fat (%) measured by the whole body dual-energy X-ray absorptiometry were also determined at baseline and at 12 weeks. RESULTS: Nineteen patients (mean age: 55 ± 12 years; 26% female) completed this study. Luseogliflozin treatment significantly reduced EFV at 12 weeks [117 (96-136) to 111 (88-134), p = 0.048]. The body weight, BMI, systolic and diastolic blood pressure, HbA1c, fasting plasma glucose, insulin, homeostasis model assessment-insulin resistance (HOMA-IR), triglycerides, SMI, and body fat were significantly reduced by luseogliflozin at 12 weeks. The reduction of EFV was significantly correlated with the reduction of C-reactive protein (r = 0.493, p = 0.019). Neither VFA nor LAI were significantly reduced by the luseogliflozin treatment. No severe adverse events were observed. CONCLUSIONS: Our data suggest that luseogliflozin could reduce the EFV in parallel with the improvement of systemic micro-inflammation and the reduction of body weight in Japanese patients with type 2 diabetes. The reduction of muscle mass after the administration of SGLT2 inhibitors may require a particular attention. Trial registration umin.ac.jp, UMIN000019072.

Clinical characteristics of definite or suspected isolated cardiac sarcoidosis: application of cardiac magnetic resonance imaging and 18F-Fluoro-2-deoxyglucose positron-emission tomography/computerized tomography.

BACKGROUND: Isolated cardiac sarcoidosis (iCS) is difficult to diagnose in patients without histologic evidence of sarcoidosis. We aimed to clarify the clinical characteristics of iCS, including imaging features on cardiac magnetic resonance imaging (MRI) and (18)F-fluoro-2-deoxyglucose positron-emission tomography/computerized tomography (FDG-PET/CT) scans. We also reviewed the therapeutic effect of corticosteroids and determined the long-term prognosis. METHODS AND RESULTS: We retrospectively reviewed 83 consecutive patients with suspicious CS from 1997 to 2013. Systemic sarcoidosis with CS (sCS, n = 30) and iCS (n = 11) were diagnosed according to clinical criteria. In iCS cases, sarcoidosis was not detected in any other organs. The clinical features did not significantly differ between sCS and iCS cases, except for ejection fraction, which was lower in iCS (P = .025). Nine sCS and 4 iCS cases showed late gadolinium enhancement, and the lesions tended to be on the epicardial side (76.9% P = .011) and septal wall (52.9% P < .001). The coefficient of variance for the myocardial standardized uptake value of FDG-PET/CT was higher in sCS (0.32 ± 0.13; n = 19) and iCS (0.32 ± 0.09; n = 7) than in control cases (n = 31; P < .001). B-Type natriuretic peptide level was improved after prednisolone treatment in both groups. Kaplan-Meier curve indicated that prognosis was not different between sCS and iCS cases. CONCLUSIONS: The clinical cardiac characteristics of iCS cases were similar to those of sCS. Cardiac MRI and FDG-PET, noninvasive imaging modalities, could be useful modalities to detect myocardial involvement in the cases with definite or suspected iCS.

Effects of intravenous atrial natriuretic peptide and nitroglycerin on coronary vasodilation and flow velocity determined using 3 T magnetic resonance imaging in patients with nonischemic heart failure.

Although atrial natriuretic peptide (ANP) is widely used in patients with congestive heart failure (CHF), little is known about its effect on epicardial coronary arteries. Magnetic resonance imaging (MRI) enables precise measurement of coronary vasodilation and flow velocity. In this study, we examined the changes in epicardial coronary artery size and flow velocity in response to intravenous infusion of ANP or nitroglycerin (NTG) by using 3 T MRI in patients with CHF. The study cohort contained a total of 14 subjects: 8 patients with CHF and 6 healthy volunteers as controls, randomly divided into two groups: the ANP group (0.03 µg/kg/min) and the NTG group (0.3 µg/kg/min). Cross-sectional MR angiography and phase-contrast flow velocity of the right coronary artery in the same in-plane slice were obtained at the baseline, during drug infusion, and at two subsequent time points after stopping drug infusion. A significant increase was observed in the coronary cross-sectional area at 15 min after drug infusion in both groups compared with that at baseline; however, a late peak was observed at 15 min after stopping infusion in the ANP group. No significant differences were detected in the flow velocity in both groups. Furthermore, although NTG increased the heart rate, this change was not found in the ANP group. Coronary vasodilation and flow velocity can be measured simultaneously using 3 T MRI. Using this method, we showed that the effects of ANP on the coronary artery vasodilation and flow velocity were not inferior to those of NTG, with no significant alteration in heart rate.

Cardiac magnetic resonance imaging in a patient with amniotic fluid embolism associated with severe cardiopulmonary complications.

Amniotic fluid embolism (AFE) is a rare but devastating complication of pregnancy. Acute circulatory failure and obstetric disseminated intravascular coagulopathy are often associated with AFE and lead to poor prognosis of this syndrome. Although many reports of AFE and its cardiopulmonary complications exist, their etiology remains unknown. Classically, it was believed that the fatal cardiopulmonary complication in AFE is due to acute and severe pulmonary hypertension caused by critical obstruction of the pulmonary vessels by embolized amniotic fluid. However, recent hypotheses are suggesting that anaphylactic reaction or a cytokine effect induced by amniotic fluid is the main pathophysiological mechanism. We report a case in which cardiac magnetic resonance imaging was performed at the chronic stage of AFE. Late gadolinium enhancement (LGE) was detected at the mid-wall of the left ventricle with no evidence of pulmonary hypertension. This finding suggests that the pathophysiological mechanism of severe cardiac complications in AFE may include direct left ventricular myocardial injury through an immune reaction or cytokine release, rather than pulmonary embolism.

Transverse and longitudinal right ventricular fractional parameters derived from four-chamber cine MRI are associated with right ventricular dysfunction etiology.

Studies of the usefulness of transverse right ventricular (RV) shortening are limited. We retrospectively analyzed the CMR images of 67 patients (age: 50.8 ± 19.0 years; men: 53.7%; Control: n = 20, Overloaded RV (atrial septal defect): n = 15, Constricted RV (pericarditis): n = 17, Degenerated RV (arrhythmogenic right ventricular cardiomyopathy): n = 15) (all enrolled consecutively for each disease) in a single center. We defined RV longitudinal (fractional longitudinal change: FLC) and transverse (fractional transverse change: FTC) contraction parameters. We assessed the FTC/FLC (T/L) ratio on four-chamber cine CMR views and compared the four groups regarding the fractional parameters. FTC had a stronger correlation (R2 = 0.650; p < 0.001) with RV ejection fraction than that with FLC (R2 = 0.211; p < 0.001) in the linear regression analysis. Both FLC and FTC were significantly lower in the Degenerated RV and Constricted RV groups compared with those in the Control and Overloaded RV groups. The T/L ratio was significantly lower in the Degenerated RV group (p = 0.008), while the Overloaded RV (p = 0.986) and Constricted RV (p = 0.582) groups had preserved T/L ratios, compared with the Control group. Transverse shortening contributes to RV function more significantly compared with longitudinal contraction. Impaired T/L ratios may reflect RV myocardial degeneration. RV fractional parameters may help precisely understand RV dysfunction.

Bioluminescence and magnetic resonance imaging of macrophage homing to experimental abdominal aortic aneurysms.

Macrophage infiltration is a prominent feature of abdominal aortic aneurysm (AAA) progression. We used a combined imaging approach with bioluminescence (BLI) and magnetic resonance imaging (MRI) to study macrophage homing and accumulation in experimental AAA disease. Murine AAAs were created via intra-aortic infusion of porcine pancreatic elastase. Mice were imaged over 14 days after injection of prepared peritoneal macrophages. For BLI, macrophages were from transgenic mice expressing luciferase. For MRI, macrophages were labeled with iron oxide particles. Macrophage accumulation during aneurysm progression was observed by in situ BLI and by in vivo 7T MRI. Mice were sacrificed after imaging for histologic analysis. In situ BLI (n  =  32) demonstrated high signal in the AAA by days 7 and 14, which correlated significantly with macrophage number and aortic diameter. In vivo 7T MRI (n  =  13) at day 14 demonstrated T2* signal loss in the AAA and not in sham mice. Immunohistochemistry and Prussian blue staining confirmed the presence of injected macrophages in the AAA. BLI and MRI provide complementary approaches to track macrophage homing and accumulation in experimental AAAs. Similar dual imaging strategies may aid the study of AAA biology and the evaluation of novel therapies.

Analysis of in situ and ex vivo vascular endothelial growth factor receptor expression during experimental aortic aneurysm progression.

OBJECTIVE: Mural inflammation and neovascularization are characteristic pathological features of abdominal aortic aneurysm (AAA) disease. Vascular endothelial growth factor receptor (VEGFR) expression may also mediate AAA growth and rupture. We examined VEGFR expression as a function of AAA disease progression in the Apolipoprotein E-deficient (Apo E(-/-)) murine AAA model. METHODS AND RESULTS: Apo E(-/-) mice maintained on a high-fat diet underwent continuous infusion with angiotensin II at 1000 ng/kg/min (Ang II) or vehicle (Control) via subcutaneous osmotic pump. Serial transabdominal ultrasound measurements of abdominal aortic diameter were recorded (n=16 mice, 3 to 4 time points per mouse) for up to 28 days. Near-infrared receptor fluorescent (NIRF) imaging was performed on Ang II mice (n=9) and Controls (n=5) with scVEGF/Cy, a single-chain VEGF homo-dimer labeled with Cy 5.5 fluorescent tracer (7 to 18 microg/mouse IV). NIRF with inactivated single chain VEGF/Cy tracer (scVEGF/In, 18 microg/mouse IV) was performed on 2 additional Ang II mice to control for nonreceptor-mediated tracer binding and uptake. After image acquisition and sacrifice, aortae were harvested for analysis. An additional AAA mouse cohort received either an oral angiogenesis inhibitor or suitable negative or positive controls to clarify the significance of angiogenesis in experimental aneurysm progression. Aneurysms developed in the suprarenal aortic segment of all Ang II mice. Significantly greater fluorescent signal was obtained from aneurysmal aorta as compared to remote, uninvolved aortic segments in Ang II scVEGF/Cy mice or AAA in scVEGF/In mice or suprarenal aortic segments in Control mice. Signal intensity increased in a diameter-dependent fashion in aneurysmal segments. Immunostaining confirmed mural VEGFR-2 expression in medial smooth muscle cells. Treatment with an angiogenesis inhibitor attenuated AAA formation while decreasing mural macrophage infiltration and CD-31(+) cell density. CONCLUSIONS: Mural VEGFR expression, as determined by scVEGF/Cy fluorescent imaging and VEGFR-2 immunostaining, increases in experimental AAAs in a diameter-dependent fashion. Angiogenesis inhibition limits AAA progression. Clinical VEGFR expression imaging strategies, if feasible, may improve real-time monitoring of AAA disease progression and response to suppressive strategies.

Right coronary wall CMR in the older asymptomatic advance cohort: positive remodeling and associations with type 2 diabetes and coronary calcium.

BACKGROUND: Coronary wall cardiovascular magnetic resonance (CMR) is a promising noninvasive approach to assess subclinical atherosclerosis, but data are limited in subjects over 60 years old, who are at increased risk. The purpose of the study was to evaluate coronary wall CMR in an asymptomatic older cohort. RESULTS: Cross-sectional images of the proximal right coronary artery (RCA) were acquired using spiral black-blood coronary CMR (0.7 mm resolution) in 223 older, community-based patients without a history of cardiovascular disease (age 60-72 years old, 38% female). Coronary measurements (total vessel area, lumen area, wall area, and wall thickness) had small intra- and inter-observer variabilities (r = 0.93~0.99, all p < 0.0001), though one-third of these older subjects had suboptimal image quality. Increased coronary wall thickness correlated with increased coronary vessel area (p < 0.0001), consistent with positive remodeling. On multivariate analysis, type 2 diabetes was the only risk factor associated with increased coronary wall area and thickness (p = 0.03 and p = 0.007, respectively). Coronary wall CMR measures were also associated with coronary calcification (p = 0.01-0.03). CONCLUSIONS: Right coronary wall CMR in asymptomatic older subjects showed increased coronary atherosclerosis in subjects with type 2 diabetes as well as coronary calcification. Coronary wall CMR may contribute to the noninvasive assessment of subclinical coronary atherosclerosis in older, at-risk patient groups.

High-contrast in vivo visualization of microvessels using novel FeCo/GC magnetic nanocrystals.

FeCo-graphitic carbon shell nanocrystals are a novel MRI contrast agent with unprecedented high per-metal-atom-basis relaxivity (r(1) = 97 mM(-1) sec(-1), r(2) = 400 mM(-1) sec(-1)) and multifunctional capabilities. While the conventional gadolinium-based contrast-enhanced angiographic magnetic MRI has proven useful for diagnosis of vascular diseases, its short circulation time and relatively low sensitivity render high-resolution MRI of morphologically small vascular structures such as those involved in collateral, arteriogenic, and angiogenic vessel formation challenging. Here, by combining FeCo-graphitic carbon shell nanocrystals with high-resolution MRI technique, we demonstrate that such microvessels down to approximately 100 mum can be monitored in high contrast and noninvasively using a conventional 1.5-T clinical MRI system, achieving a diagnostic imaging standard approximating that of the more invasive X-ray angiography. Preliminary in vitro and in vivo toxicity study results also show no sign of toxicity.

A human ferritin iron oxide nano-composite magnetic resonance contrast agent.

Macrophages play important roles in the immunological defense system, but at the same time they are involved in inflammatory diseases such as atherosclerosis. Therefore, imaging macrophages is critical to assessing the status of these diseases. Toward this goal, a recombinant human H chain ferritin (rHFn)-iron oxide nano composite has been investigated as an MRI contrast agent for labeling macrophages. Iron oxide nanoparticles in the form of magnetite (or maghemite) with narrow size distribution were synthesized in the interior cavity of rHFn. The composite material exhibited the R(2) relaxivity comparable to known iron oxide MRI contrast agents. Furthermore, the mineralized protein cages are readily taken up by macrophages in vitro and provide significant T2* signal loss of the labeled cells. These results encourage further investigation into the development of the rHFn-iron oxide contrast agent to assess inflammatory disease status such as macrophage-rich atherosclerotic plaques in vivo.

Antibacterial cotton fabrics based on hydrophilic amino-containing scaffolds.

A hydrophilic amino compound, 4,7,10-trioxatridecane-1,13-diamine, has been utilized in several chemical and biochemical studies. Among previous applications is its use as a flexible and economical spacer molecule to increase the length between two moieties of interest, one of which may be a solid-phase interface. In this study, we immobilized this molecule on cotton fabrics and showed that this modified surface (DA) exhibited significant antibacterial activities in both Gram-negative bacteria and a Gram-positive bacterium. Studies on the structure-activity relationship revealed that additional chemical modifications on DA usually led to lowered antibacterial activities, emphasizing an importance of having free amino groups. Further investigation by fluorescence microscope indicated that this modified surface likely interfered with the membrane integrity of bacteria, leading to cell lysis. In addition, this scaffold was also tested for its biocompatibility with mouse fibroblast cells, and exerted no detrimental effect to the cell growth, highlighting its potential as a practical antibacterial surface modifier.

Cardiac Magnetic Resonance Imaging of Very Late Intrapericardial Hematoma 8 Years after Coronary Artery Bypass Grafting.

A 55-year-old man presented with dyspnea, edema, and appetite loss. He had undergone coronary artery bypass grafting 8 years previously. He had jugular venous distention and Kussmaul's sign. Contrast-enhanced cardiac magnetic resonance imaging (CMRI) demonstrated an intrapericardial mass compressing the right ventricular (RV) cavity. T1- and T2-weighted black-blood images showed a mass with heterogeneous high signal intensity and a thick and dark rim. The mass was considered to be a chronic hematoma. After pericardiotomy with surgical removal of the hematoma, CMRI showed the marked improvement of the RV function. Late intrapericardial hematoma is rare and CMRI is useful for making a differential diagnosis.

Ipragliflozin Reduces Epicardial Fat Accumulation in Non-Obese Type 2 Diabetic Patients with Visceral Obesity: A Pilot Study.

INTRODUCTION: Epicardial fat (EF) was reported to be independently associated with cardiovascular disease regardless of obesity. We have previously reported that a sodium-glucose co-transporter-2 (SGLT2) inhibitor, luseogliflozin, reduces the EF volume (EFV) in parallel with the reduction of body weight in obese patients (BMI ≥25 kg/m2) with type 2 diabetes. However, it is unknown whether SGLT2 inhibitors could reduce EFV in non-obese patients (BMI <25 kg/m2) with type 2 diabetes. Therefore, we evaluated the effect of SGLT2 inhibitors on the EFV in non-obese type 2 diabetic patients with visceral obesity in this pilot study. METHODS: Nine of type 2 diabetic patients (mean age 66 ± 8 years; 33% female) with HbA1c 6.5-9.0%, body mass index (BMI, kg/m2) <25.0, and visceral fat area (VFA, cm2) ≥100 were enrolled. Participants were administered ipragliflozin 50 mg daily. EFV [median (interquartile range), cm3] was measured by magnetic resonance imaging. Primary endpoint was the change in EFV at 12 weeks. VFA and liver attenuation index (LAI), skeletal muscle index (SMI), and body fat (%) were also assessed at baseline and at 12 weeks. RESULTS: The EFV was significantly reduced from 102 (79-126) cm3 to 89 (66-109) cm3 by ipraglifrozin (p = 0.008). The body weight, BMI, HbA1c, fasting plasma glucose, insulin, homeostasis model assessment-insulin resistance, triglycerides, leptin, body fat, android, gynoid, and VFA were significantly reduced and high-density lipoprotein cholesterol was significantly increased by ipraglifrozin at 12 weeks, whereas SFA and LAI were unchanged. The change in EFV was significantly correlated with the change in BMI. CONCLUSIONS: A12-week intervention of ipragliflozin reduced the EFV in non-obese type 2 diabetic patients with visceral adiposity. CLINICAL TRIAL REGISTRATION: UMIN Clinical Trial Registry: UMIN000019071. FUNDING: Astellas Pharma Inc. and the Grants-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology of Japan.

Noninvasive assessment of coronary vasodilation using magnetic resonance angiography.

OBJECTIVES: The purpose of this study was to investigate the use of coronary magnetic resonance angiography (MRA) for assessing human epicardial coronary artery vasodilation. BACKGROUND: Coronary vasodilation plays a vital role in the human coronary circulation. Previous studies of epicardial coronary vasodilation have used invasive coronary angiography. Coronary MRA may provide an alternative noninvasive method to directly assess changes in coronary size. METHODS: Thirty-two subjects were studied: 12 patients (age 55 +/- 18 years) and 20 healthy subjects (age 34 +/- 4 years). High-resolution multi-slice spiral coronary MRA (in-plane resolution of 0.52 to 0.75 mm) was performed before and after sublingual nitroglycerin (NTG). Quantitative analysis of coronary vasodilation was performed on cross-sectional images of the right coronary artery (RCA). A time-course analysis of coronary vasodilation was performed in a subset of eight subjects for 30 min after NTG. Signal-to-noise ratio was also measured on the in-plane RCA images. RESULTS: Coronary MRA demonstrated a 23% increase in cross-sectional area after NTG (16.9 +/- 7.8 mm2 to 20.8 +/- 8.9 mm2, p <0.0001), with significant vasodilation between 3 and 15 min after NTG on time-course analysis. The MRA measurements had low interobserver variability (< or =5%) and good correlation with X-ray angiography (r=0.98). The magnitude of vasodilation correlated with baseline cross-sectional area (r=0.52, p=0.03) and age (r=0.40, p=0.019). Post-NTG images also demonstrated a 31% improvement in coronary signal-to-noise ratio (p = 0.002). CONCLUSIONS: Nitroglycerin-enhanced coronary MRA can noninvasively measure coronary artery vasodilation and is a promising noninvasive technique to study coronary vasomotor function.

Spiral magnetic resonance coronary angiography with rapid real-time localization.

A spiral high-resolution coronary artery imaging sequence (SH) interfaced with real-time localization system (RT) has been developed. A clinical study of 40 patients suspected of coronary artery disease (CAD) was conducted. Segmented k-space acquisition techniques have dominated magnetic resonance coronary angiography (MRCA) over the last decade. Although a recent multicenter trial using this technique demonstrated encouraging results, the technique was hampered by low specificity. Spiral k-space acquisition had demonstrated several advantages for MRCA. Therefore, a first clinical trial implementing spiral high-resolution coronary imaging sequence with real-time localization (SH-RT) was performed.A clinical study of 40 patients suspected of CAD undergoing X-ray angiography was conducted to analyze the clinical reliability of this novel imaging system. The SH-RT had been designed to exploit the unique capability of two imaging sequences. The RT allowed a rapid localization of the coronary arteries. Then SH achieved multislice acquisition during a short breath-hold with submillimeter resolution. The MRCA data were analyzed for scan time, anatomic coverage, image quality, and accuracy in detecting CAD. In 40 subjects, SH achieved 0.7 to 0.9 mm resolution with 14-heartbeat breath-holds. Excellent or good image quality was achieved in 78% (263/337) of the coronary segments. Blinded consensus reading among three observers generated sensitivity of 76% and specificity of 91% in the detection of CAD compared with X-ray angiography. The MRCA imaging sequence implementing a novel spiral k-space acquisition technique enabled rapid and reliable imaging of the CAD in submillimeter resolution with short breath-holds.

Vessel Wall Inflammation of Takayasu Arteritis Detected by Contrast-Enhanced Magnetic Resonance Imaging: Association with Disease Distribution and Activity.

AIMS: The assessment of the distribution and activity of vessel wall inflammation is clinically important in patients with Takayasu arteritis. Magnetic resonance imaging (MRI) is a useful tool, but the clinical utility of late gadolinium enhancement (LGE) in Takayasu arteritis has yet to be determined. The aim of the present study was to evaluate the utility of LGE in assessing vessel wall inflammation and disease activity in Takayasu arteritis. METHODS AND RESULTS: We enrolled 49 patients with Takayasu arteritis who had undergone 1.5 T MRI. Patients were divided into Active (n = 19) and Inactive disease (n = 30) groups. The distribution of vessel wall inflammation using angiography and LGE was assessed by qualitative analysis. In 79% and 63% of patients in Active and Inactive groups, respectively, greater distribution of vessel wall inflammation was observed with LGE than with conventional angiography. MRI values of pre- and post-contrast signal-to-noise ratios (SNR), SNR increment (post-SNR minus pre-SNR), pre- and post-contrast contrast-to-noise ratios (CNR), and CNR increment (post-CNR minus pre-CNR) were evaluated at arterial wall sites with the highest signal intensity using quantitative analysis of post-contrast LGE images. No statistically significant differences in MRI parameters were observed between Active and Inactive groups. Contrast-enhanced MRI was unable to accurately detect active disease. CONCLUSION: Contrast-enhanced MRI has utility in detecting the distribution of vessel wall inflammation but has less utility in assessing disease activity in Takayasu arteritis.

Arg389Gly polymorphism of the human beta1-adrenergic receptor in patients with nonfatal acute myocardial infarction.

BACKGROUND: We sought to investigate the relation between the Arg389Gly polymorphism in the human beta1-adrenergic receptor (ADRB1) gene and acute myocardial infarction (AMI). It was previously reported that augmented sympathetic activity might play an important role as a trigger of AMI by enhanced hemodynamic or mechanical forces through ADRB1 activation. Recently, a common polymorphism has been identified at amino acid position 389 (Arg or Gly) of the human ADRB1, within a region important for receptor-Gs protein coupling and subsequent agonist-stimulated adenylyl cyclase activation. METHODS: To investigate the relation between the Arg389Gly polymorphism in the ADRB1 gene and AMI, we genotyped 354 patients with AMI and 354 age- and sex-matched control subjects by use of polymerase chain reaction amplification and the restriction fragment length polymorphism analysis. RESULTS: The prevalence of the Arg389 homozygote (CC) genotype was significantly more frequent in patients with AMI than in control subjects (68.1% vs 47.2%, P <.0001). In logistic regression models, the odds ratio (OR) of Arg389 homozygote (CC) versus Arg389Gly heterozygote (CG) + Gly389 homozygote (GG) genotypes between control subjects and patients with AMI was 2.86 (95% CI 1.92-4.26, P =.0001). The association of the Arg389Gly polymorphism of ADRB1 with AMI was statistically significant and independent of other risk factors. CONCLUSION: Our findings suggest that the genotype of Arg389Gly polymorphism in the human ADRB1 gene is associated with AMI.