Denoising parameter dependence of coronary artery depictability in compressed sensing magnetic resonance angiography.

Using numerical indices and visual evaluation, we evaluated the dependence of coronary-artery depictability on the denoising parameter in compressed sensing magnetic resonance angiography (CS-MRA). This study was conducted to clarify the acceleration factor (AF) and denoising factor (DF) dependence of CS-MRA image quality. Vascular phantoms and clinical images were acquired using three-dimensional CS-MRA on a clinical 1.5 T system. For the phantom measurements, we compared the full width at half maximum (FWHM), sharpness, and contrast ratio of the vascular profile curves for various AFs and DFs. In the clinical cases, the FWHM, sharpness, contrast ratio, signal-to-noise ratio, noise level values, and visual evaluation results were compared for various DFs. Phantom image analyses demonstrated that the respective measurements of the FWHM, sharpness, and contrast ratios did not significantly change with an increase in AF. The FWHM and sharpness measurements slightly changed with the DF level. However, the contrast ratio tended to increase with an increase in the DF level. In the clinical cases, the FWHM and sharpness showed no significant differences, even when the DF level was changed. However, the contrast ratio tended to decrease as the DF level increased. When the DF levels of the clinical cases increased, the background signals of the myocardium, fat, and noise levels decreased. We investigated the dependence of the coronary-artery depictability on AF and DF using CS-MRA. Analysis of the coronary-artery profile curves indicated that a better image quality was achieved with a stronger DF on coronary CS-MRA.

Detection of intracranial aneurysms using deep learning-based CAD system: usefulness of the scores of CNN's final layer for distinguishing between aneurysm and infundibular dilatation.

PURPOSE: We evaluated the diagnostic performance of a clinically available deep learning-based computer-assisted diagnosis software for detecting unruptured aneurysms (UANs) using magnetic resonance angiography and assessed the functionality of the convolutional neural network (CNN) final layer score for distinguishing between UAN and infundibular dilatation (ID). MATERIALS AND METHODS: EIRL brain aneurysm (EIRL_BA) was used in this study. The subjects were 117 UAN and/or ID cases including 100 UAN lesions (average sizes of 2.56 ± 1.45 mm) and 40 ID lesions (average sizes of 1.75 ± 0.41 mm) in any of internal carotid artery, middle cerebral artery, and anterior communicating artery, and 123 normal controls. The sensitivity, specificity, and accuracy of EIRL_BA were determined for UAN and ID or UAN only. Furthermore, the relationship between the lesion category and score was examined using a linear regression analysis model, and the receiver operating characteristic (ROC) analysis was used to assess whether the scores represent UAN-like characteristics. RESULTS: EIRL_BA showed a total of 203 candidates (an average of 1.73/case) in UAN and/or ID cases and 98 candidates (an average of 0.80/case) in normal controls. For diagnosing either UAN/ID, EIRL_BA showed an overall sensitivity of 80%, specificity of 84.2%, and accuracy of 83.7%, resulting in the positive likelihood ratio of 5.0. For diagnosing UAN only, the overall sensitivity of 89.0, specificity of 82.6%, and accuracy of 83.2% resulting in the positive likelihood ratio of 5.1. In a linear regression analysis, the scores significantly increased in the candidates' first and second ranks in UAN (p < 0.05) but not in ID. An ROC analysis using the score for diagnosing UAN showed an area under the curve of 0.836. CONCLUSION: EIRL_BA is applicable for detecting small UAN, and the CNN's final layer scores may be an effective index for discriminating UAN and ID and representing the likelihood of UAN.

Noise power spectrum in compressed sensing magnetic resonance imaging.

Compressed sensing magnetic resonance imaging (CS-MRI) uses random undersampling and nonlinear iterative reconstruction. This study was conducted to clarify the noise power spectrum (NPS) characteristics of CS-MRI. We measured two-dimensional (2D) NPS of CS-MRI with various acceleration factors (AF) and denoising factors (DF) and compared their appearance to those of conventional parallel MR images. Results showed that the 2D NPS of CS-MRI exhibited the following characteristics: (1) local decrease in the low-frequency region, (2) gradual decrease in the high-frequency region, and (3) a stripe pattern aligned at unequal intervals in the phase-encoding direction. Specifically, the 2D NPS of CS-MRI reflects the random undersampling pattern of k-space data. Additionally, 2D NPS allowed visualization of AF-dependent noise characteristics of CS-MRI. Furthermore, 1D NPS graph shapes clarified the CS-MRI noise characteristic dependence on AF and DF.

A pooled-analysis of age and sex based coronary artery calcium scores percentiles.

BACKGROUND: Age and sex based coronary artery calcium score (CAC) percentiles have been used to improve coronary artery disease (CAD) risk prediction. However, the main limitation of the CACs percentiles currently in use is that they are often based on single studies. We performed a pooled analysis of all available studies that reported on CAC percentiles, in order to develop more generalizable age and sex nomograms. METHODS: PubMed/Medline and Embase were searched for studies that reported nomograms of age and sex-based CACs percentiles. Studies were included if they reported data collected among asymptomatic individuals without a history of cardiovascular disease. Absolute CACs for each specific percentile stratum were pooled and new percentiles were generated taking into account the sample size of the study. RESULTS: We found 831 studies, of which 12 met the inclusion criteria. Data on CACs percentiles of 134,336 Western and 33,488 Asians were pooled separately, rendering a weighted CACs percentile nomogram available at https://www.calciumscorecalculator.com. Our weighted percentiles differed by up to 24% from the nomograms in use today. CONCLUSIONS: Our pooled age and sex based CACs percentiles based on over 155,000 individuals should provide a measure of risk that is more applicable to a wider population than the ones currently in use and hopefully will lead to better risk assessment and treatment decisions.

Comparison of axial and coronal acquisitions by non-contrast-enhanced renal 3D MR angiography using flow-in time-spatial labeling inversion pulse.

OBJECTIVE: We evaluated image quality differences between axial and coronal non-contrast-enhanced renal three-dimensional (3D) magnetic resonance angiography (MRA) acquisitions, using time-spatial labeling inversion pulse (Time-SLIP) with flow-in balanced steady-state free precession (bSSFP). MATERIALS AND METHODS: Axial and coronal images were acquired in 128 subjects using non-contrast-enhanced 3D-MRA with Time-SLIP flow-in bSSFP on a clinical 1.5-T MRI system. Visualization of source and maximum intensity projection (MIP) images of renal arteries were compared between the axial and coronal acquisitions using a four-point scale. For quantitative analysis, vessel-to-background contrast ratios of aorta and renal arteries were calculated. RESULTS: Both acquisitions yielded similarly excellent quality. In source image evaluation, coronal acquisitions showed significantly more motion degradation (p < 0.01) than did axial acquisitions. In MIP image evaluation, coronal acquisitions yielded superior image quality, less motion degradation, and better visualization of the number of renal branches than did axial acquisition. The renal artery to background signal contrast was greater in coronal than in axial acquisitions (p < 0.01). CONCLUSION: Coronal acquisition provides superior contrast between the renal arteries and background and allows more persistent visualization than axial acquisitions in non-contrast-enhanced MRA using flow-in bSSFP with Time-SLIP. First-line screening of renal non-contrast-enhanced MRA should involve coronal acquisition.

Prevalence and distribution of coronary calcium in asymptomatic Japanese subjects in lung cancer screening computed tomography.

BACKGROUND: Coronary artery calcium (CAC) is associated with a risk of coronary heart disease. The prevalence and distribution of the CAC score have been examined in Western countries, but few studies have been performed in Asia, and especially in Japan. The goal of this study was to investigate CAC scores in an asymptomatic Japanese population. METHODS: CAC score and risk factors were analyzed in 1834 asymptomatic subjects who underwent lung cancer screening computed tomography. RESULTS: CAC was present in 26.9% of all the subjects, 29.8% of the males, and 17.1% of the females. In all age groups, the CAC score was higher in males. In multivariate analysis, male gender [odds ratio (OR) 2.461, 95% confidence interval (CI) 1.361-4.452, p=0.002], aging (OR 1.102, 95% CI 1.081-1.123, p<0.001), dyslipidemia (OR 1.740, 95% CI 1.216-2.490, p=0.002), and fasting glucose (OR 1.008, 95% CI 1.002-1.015, p=0.012) were significantly associated with a CAC score >100. CONCLUSION: The results of this study provide a pattern of CAC distribution based on age and gender in asymptomatic Japanese subjects. This pattern was similar to that in Western countries, although the absolute CAC scores were lower. High CAC scores were associated with male gender, aging, dyslipidemia, and fasting glucose.

Relationship between Alcohol Intake and Risk Factors for Metabolic Syndrome in Men.

OBJECTIVE: The precise relationship between alcohol intake and metabolic syndrome (MetS) is still unclear, and the results from previous studies have been inconclusive. Thus, we examined the effect of alcohol intake on the risk of MetS in men in order to gain more information on a potential relationship. METHODS: This study included 22,349 men who were divided into four groups according to their average alcohol intake [non-, light (less than 20 g ethanol/day), heavy (equal or more than 20 g and less than 60 g ethanol/day) and very heavy (equal and greater than 60 g ethanol/day) drinkers]. We measured each subject's body mass index (BMI), waist circumference and blood pressure (BP) and conducted a blood test to obtain a complete blood count and biochemical panel. These results were used to obtain the MetS prevalence. Additionally, fatty liver was diagnosed using abdominal ultrasonography. RESULTS: Light drinkers had smaller waist circumferences. Heavy and very heavy drinkers had larger waist circumferences, a higher BMI, a higher BP, higher fasting plasma glucose levels, higher triglycerides (TG) levels and higher high-density lipoprotein (HDL) cholesterol levels while they had lower low-density lipoprotein cholesterol levels than nondrinkers. The prevalence of high BP, hyperglycemia and high TG was significantly higher in heavy and very heavy drinkers than in nondrinkers. The prevalence of low HDL cholesterol levels decreased with an increase in alcohol consumption. The prevalence of MetS was significantly lower in light drinkers and higher in very heavy drinkers compared with nondrinkers. CONCLUSION: Alcohol intake significantly influences the risk of MetS in men. A significant association was seen between an alcohol intake of 60 g/day or higher and the prevalence of MetS.

Potential impact of joint association of alanine aminotransferase and gamma-glutamyltransferase on insulin resistance in Japan: The Toranomon Hospital Health Management Center Study 19 (TOPICS 19).

AIM: To investigate the potential impact of joint association of alanine aminotransferase (ALT) and γ-glutamyltransferase (GGT) on insulin resistance and ß-cell dysfunction in healthy Japanese individuals with a normal range of liver enzymes. METHODS: This study included 1010 individuals (545 men and 465 women) aged 20-89 years who underwent an oral glucose tolerance test for health screening. Participants were divided into four groups on the basis of median values for ALT and GGT: (i) both ALT and GGT low (both-low); (ii) ALT high and GGT low (ALT-high); (iii) ALT low and GGT high (GGT-high); and (iv) both ALT and GGT high (both-high). Logistic regression analysis was used to investigate the relationship between liver enzyme and insulin dynamics, such as Homeostasis Model of Assessment - Insulin Resistance (HOMA-IR) and insulinogenic index (IGI). The insulin resistance was defined when HOMA-IR was 2.5 or more. IGI of less than 0.4 was considered to be decreased early-phase insulin secretion. RESULTS: Mean values of HOMA-IR in men was 1.5 in the both-low group, 1.8 in ALT-high, 1.8 in GGT-high and 2.8 in both-high. The mean HOMA-IR in women was 1.3 in the both-low group, 1.3 in ALT-high, 1.6 in GGT-high and 2.0 in both-high. HOMA-IR in the both-high group was significantly higher than that in the both-low group regardless of the difference of sex. Multivariate analysis showed that insulin resistance occurred when the patient had high liver enzymes. CONCLUSION: Combining the two liver function markers would be effective for identifying individuals with insulin resistance.

Prognostic factors for regression from impaired glucose tolerance to normal glucose regulation in Japanese patients with nonalcoholic fatty liver disease.

OBJECTIVE: The aim of this retrospective cohort study was to assess the predictive factors for the regression from impaired glucose tolerance (IGT) to normal glucose regulation (NGR) in patients with nonalcoholic fatty liver disease (NAFLD). METHODS: A total of 164 NAFLD patients who had IGT in the first 75-g oral glucose tolerance test (OGTT) and underwent a repeated OGTT five years later were enrolled. A multivariate logistic regression analysis was carried out to identify factors predicting the regression from IGT to NGR. RESULTS: Out of the 164 patients, 29 regressed from IGT to NGR within five years after the first OGTT. The multivariate analysis by logistic regression showed that regression from IGT to NGR occurred when the patient was young (risk ratio for ten years: 0.38; 95% confidence interval [CI] 0.20-0.72; p=0.003), had a fasting plasma glucose (FPG) level of <100 mg/dL (risk ratio: 6.53; 95%CI 1.88-21.73; p=0.003), had a 2-hr post-load plasma glucose (PG) level of <160 mg/dL (risk ratio: 4.86; 95%CI 1.08-22.72; p=0.040), a body mass index (BMI) decrease of ≥1.5 (risk ratio: 5.20; 95% CI 1.41-19.24; p=0.014), physical activity of ≥2 Metabolic Equivalent of Task (MET) h/day (risk ratio: 5.57; 95%CI 1.68-18.44; p=0.005), and showed disappearance of the fatty liver by ultrasonography at five years (risk ratio: 9.92; 95%CI 2.87-34.34; p<0.001). CONCLUSION: Our results suggest that six factors: young age, FPG <100 mg/dL, 2-hr post-load PG of <160 mg/dL, BMI decrease of ≥1.5, physical activity of ≥2 MET h/day, and the disappearance of fatty liver predict the regression from IGT to NGR in NAFLD patients.

Giant coronary artery aneurysms associated with Kawasaki disease detected on whole-heart magnetic resonance coronary angiographic screening.

Kawasaki disease (KD) is one of the most important causes of coronary artery aneurysms in children and young adults. However, the natural course of the disease and the patient prognosis remain obscure. A 72-year-old asymptomatic man with undiagnosed KD underwent whole-heart magnetic resonance coronary angiography during a health checkup. The imaging disclosed giant aneurysms in the proximal portion of the right coronary artery and the left anterior descending artery. The patient was successfully treated with coronary artery bypass grafting. The present case suggests that there may be a substantial number of patients who have attained middle to old age with undiagnosed KD.

Efficacy and safety in sitagliptin therapy for diabetes complicated by non-alcoholic fatty liver disease.

AIM: The aim of this case-control study was to assess the efficacy and safety of dipeptidyl peptidase-4 inhibitor (sitagliptin) for type 2 diabetes mellitus (T2DM) with non-alcoholic fatty liver disease (NAFLD). METHODS: Twenty NAFLD patients with T2DM treated by sitagliptin were retrospectively enrolled as the sitagliptin group. These patients were given sitagliptin between January 2010 and July 2011. Another 20 NAFLD patients with T2DM treated only with diet and exercise for 48 weeks were selected as the control group. Serum levels of fasting plasma glucose (FPG), hemoglobin A1C (HbA1c), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were measured before and 12, 24, 36 and 48 weeks after the initiation of treatment. RESULTS: In the sitagliptin group, average HbA1c levels decreased approximately 0.7% at 48 weeks after the initiation of sitagliptin. Next, average FPG levels decreased approximately 15 mg/dL at 48 weeks after the initiation of sitagliptin. The serum levels of HbA1c and FPG in the sitagliptin group decreased with statistical significance compared to those in the control group (P < 0.05). All the patients could take sitagliptin of 50 mg/day without reduction necessitated by sitagliptin-related side-effects. There were no significant changes of average AST and ALT levels during follow up of 48 weeks in both sitagliptin and control groups. CONCLUSION: Our results indicate sitagliptin is effective and safe for the treatment of T2DM complicated with NAFLD.

A new therapeutic strategy for hypertrophic nonobstructive cardiomyopathy in humans. A randomized and prospective study with an Angiotensin II receptor blocker.

A randomized and prospective study was designed to prove the efficacy of angiotensin II receptor blockers (ARB) in the amelioration of myocardial impairment in hypertrophic nonobstructive cardiomyopathy (HNCM). Nineteen consecutive patients with HNCM were randomly assigned to two groups and then underwent cine magnetic resonance evaluation of left ventricular mass (LVM) twice just before and after one year of observation. In the ARB group, 50 mg of losartan potassium was administered once daily during the observation period. The ratio of LVM after the observation period over that before the period was blindly compared between the two groups to estimate morphologically the ameliorative effect of ARB. In the ARB group, LVM was 203 +/- 47 cm(3) before the treatment period and 190 +/- 55 cm(3) after the period and the ratio of the final LVM over the initial LVM was 0.93 +/- 0.10. In the non-ARB group the initial and final LVM values were 177 +/- 48 cm(3) and 179 +/- 45 cm(3), and the ratio of the final LVM over the initial LVM was 1.02 +/- 0.07. The ratio of the final LVM over the initial LVM in the ARB group was significantly smaller (P = 0.03) than that in the non-ARB group. The smaller ratio in the ARB group strongly indicates that ARB ameliorated the natural course of HNCM during the one year observation period. Thus, this is the first demonstration of the therapeutic efficacy of ARB in human HNCM.

Gender-specific clinical characteristics of deep Q waves in hypertrophic cardiomyopathy.

BACKGROUND: Despite male predominance in the prevalence of hypertrophic cardiomyopathy (HCM), repeated diagnosis at our institute indicates a possible higher prevalence of deep Q waves with HCM in women. OBJECTIVE: The current study examined gender similarities and differences in the prevalence of deep Q waves in HCM and in the morphologic and electrocardiographic features of HCM with deep Q waves. METHODS: Patients with HCM underwent cardiac magnetic resonance (CMR) imaging to identify the prevalence of deep Q waves in electrocardiographic limb leads, and to analyze the relationship between distribution patterns of deep Q waves and those of the localization of maximum amplitude of left ventricular (LV) hypertrophy. Contiguous LV short-axis images were obtained from the base toward the apex. RESULTS: Of the 200 consecutive patients (172 males, aged 20-78 years; 28 females, aged 16-79 years) with HCM who underwent CMR imaging, 10 male and 8 female patients had deep Q waves. Deep Q waves were more prevalent in females with HCM than in their male counterparts (28.6% vs 5.8%, respectively; P<0.001). Of the 18 patients with deep Q waves, maximum wall thickness was localized at either the basal anterior wall or the midventricular septum in 9 (90%) of the 10 male patients and 6 (75%) of the 8 female patients. In both sexes, the Q wave distribution pattern of I and aVL and of II and aVF indicated localization of maximum hypertrophy at the midventricular septum in 6 (75%) of the 8 patients with the former pattern, and at the basal anterior wall in 9 (90%) of the 10 patients with the latter pattern. CONCLUSIONS: Diagnostic deep Q waves were detected more frequently in female patients with HCM than in their male counterparts. In HCM with deep Q waves in limb leads, morphologic and electrocardiographic analysis showed similar features in both sexes.

Role of sarcolemmal K(ATP) channels in cardioprotection against ischemia/reperfusion injury in mice.

Recently it has been postulated that mitochondrial ATP-sensitive K(+) (mitoK(ATP)) channels rather than sarcolemmal K(ATP) (sarcK(ATP)) channels are important as end effectors and/or triggers of ischemic preconditioning (IPC). To define the pathophysiological significance of sarcK(ATP) channels, we conducted functional experiments using Kir6.2-deficient (KO) mice. Metabolic inhibition with glucose-free, dinitrophenol-containing solution activated sarcK(ATP) current and shortened the action potential duration in ventricular cells isolated from wild-type (WT) but not KO mice. MitoK(ATP) channel function was preserved in KO ventricular cells. In anesthetized mice, IPC reduced the infarct size in WT but not KO mice. Following global ischemia/reperfusion, the increase of left ventricular end-diastolic pressure during ischemia was more marked, and the recovery of contractile function was worse, in KO hearts than in WT hearts. Treatment with HMR1098, a sarcK(ATP) channel blocker, but not 5-hydroxydecanoate, a mitoK(ATP) channel blocker, produced a deterioration of contractile function in WT hearts comparable to that of KO hearts. These findings suggest that sarcKATP channels figures prominently in modulating ischemia/reperfusion injury in the mouse. The rapid heart rate of the mouse (>600 beats per minute) may magnify the relative importance of sarcK(ATP) channels during ischemia, prompting caution in the extrapolation of the conclusions to larger mammals.