Raise-up technique for the creation of left atrial roof lesion: A useful technique with cryoballoon for persistent atrial fibrillation.

INTRODUCTION: Recent studies have reported the efficacy of the cryoballoon (CB)-guided left atrial roof block line (LARB) creation in patients with persistent atrial fibrillation (AF). However, it can be technically challenging to attach the balloon to the left atrial (LA) roof due to its anatomical variations. We designed a new procedure called the "Raise-up Technique," which may facilitate the firm adhesion of the CB to the LA roof during freezing. This study aimed to evaluate the efficacy of the Raise-up technique in LARB creation. METHODS AND RESULTS: In total, 100 consecutive patients with persistent AF who underwent CB-LARB creation were enrolled. Fifty-seven patients underwent LARB creation using the Raise-up technique (Raise-up group), and the remaining 43 did not use it (control group). The Raise-up technique was performed as follows: An Achieve catheter was inserted as deeply as possible into the upper branch of the right superior pulmonary vein to anchor the CB. The balloon was placed below the targeted site on the LA roof and frozen. When the temperature of the CB reached approximately -10°C and the CB was easier to attach to the LA tissue, the CB was raised and pressed against the LA roof immediately by sheath advancement. Then the balloon could be in firm contact with the target site on the roof. If necessary, additional sheath advancement after sufficient freezing (-20°C to -30°C) was allowed the CB to have more firm and broad contact with the target site. LARB creation without touch-up ablation was achieved in 54 of 57 patients (94.7%) in the Raise-up group and 33 of 43 patients (76.7%) in the control group (p < .05). The lesion size of the LARB in the Raise-up group was significantly larger than that in the control group (15.2 cm2 vs. 12.8 cm2, p < .05). Moreover, the width of the LARB lesion in the Raise-up group was wider than that in the control group (32.0 mm vs. 26.6 mm, p < .05). CONCLUSION: The Raise-up technique enabled the creation of seamless and thick LARB lesions with a single stroke. In addition, the CB-LARB lesions created using the Raise-up technique tended to be large, resulting in extensive debulking of the LA posterior wall arrhythmia substrates. In CB ablation for persistent AF, the Raise-up technique can be considered one of the key strategies for LARB creation.

Clinical Effect of Adaptive Servo-Ventilation on Left Atrial Pressure During Catheter Ablation in Sedated Patients With Atrial Fibrillation.

BACKGROUND: Sedation during pulmonary vein isolation (PVI) for atrial fibrillation often provokes a decline in left atrial (LA) pressure (LAP) under atmospheric pressure and increases the risk of systemic air embolisms. This study aimed to investigate the efficacy of adaptive servo-ventilation (ASV) on the LAP in sedated patients.Methods and Results:Fifty-one consecutive patients undergoing cryoballoon PVI were enrolled. All patients underwent sedation using propofol throughout the procedure. After the transseptal puncture and the insertion of a long sheath into the LA, the LAP was measured. Then, the ASV treatment was started, and the LAP was re-measured. The LAP before and after the ASV support was investigated. Before ASV, the LAP during the inspiratory phase was significantly smaller than that during the expiratory phase (4.9±5.4 mmHg vs. 14.0±5.2 mmHg, P<0.01). The lowest LAP was -2.2±5.1 mmHg and was under 0 mmHg in 37 (73%) patients. After the ASV, the LAP during the inspiratory phase significantly increased to 8.9±4.1 mmHg (P<0.01), and lowest LAP increased to 4.7±5.9 mmHg (P<0.01). The negative lowest LAP value became positive in 30/37 (81%) patients. There were no statistical differences regarding obstructive sleep apnea (OSA), obesity, gender, or other comorbidities between patients with and without a negative lowest LAP after ASV support. CONCLUSIONS: ASV is effective for increasing the LAP above 0 mmHg and might prevent air embolisms during PVI.

Clinical significance of early systolic reverse flow in left anterior descending coronary artery on transthoracic echocardiography in patients with acute myocardial infarction.

BACKGROUND: Predicting the cardiac function in chronic phase of acute myocardial infarction (AMI) patients is important. Previous studies showed that the presence of early systolic reverse flow (ESRF) in coronary flow measured with a Doppler guide wire is a predictor of worsening chronic phase function in patients with anterior AMI. We routinely examined the coronary flow velocity (CFV) of the distal left anterior descending artery (LAD) using transthoracic echocardiography (TTE) in AMI patients. The aim of this study is to investigate whether the ESRF in TTE is associated with the chronic cardiac function, recovery of cardiac function, and the incidence of major adverse cardiac events (MACE) in patients with anterior AMI. METHODS: We enrolled 84 patients with their first anterior AMI. Using TTE, we recorded the CFV of distal LAD within 5 days after primary percutaneous coronary intervention. Patients were divided into two groups, ESRF + group (ESRF was detected in TTE: 21 cases) and ESRF- group (ESRF was not detected in TTE: 63 cases). We compared chronic cardiac function in TTE, changes in cardiac function in acute and chronic phase (ΔLVEF, ΔLVDd), and the incidence of MACE. RESULTS: The incidence of MACE in ESRF-group was lower than that in ESRF + group (3.3% vs 19.1% P = .02). LVEF in chronic phase in ESRF- group was higher than that in ESRF + group (54.1 ± 5.6% vs 40.4 ± 6.2% P < .001). ΔLVDd was smaller in ESRF-group than ESRF + group (-0.62 ± 4.0 mm vs +5.06 ± 3.4 mm P = .003). CONCLUSION: Early systolic reverse flow in TTE is a predictor of chronic cardiac function and incidence of MACE in patients with anterior AMI.

Atlantic hurricane surge response to geoengineering.

Devastating floods due to Atlantic hurricanes are relatively rare events. However, the frequency of the most intense storms is likely to increase with rises in sea surface temperatures. Geoengineering by stratospheric sulfate aerosol injection cools the tropics relative to the polar regions, including the hurricane Main Development Region in the Atlantic, suggesting that geoengineering may mitigate hurricanes. We examine this hypothesis using eight earth system model simulations of climate under the Geoengineering Model Intercomparison Project (GeoMIP) G3 and G4 schemes that use stratospheric aerosols to reduce the radiative forcing under the Representative Concentration Pathway (RCP) 4.5 scenario. Global mean temperature increases are greatly ameliorated by geoengineering, and tropical temperature increases are at most half of those temperature increases in the RCP4.5. However, sulfate injection would have to double (to nearly 10 teragrams of SO2 per year) between 2020 and 2070 to balance the RCP4.5, approximately the equivalent of a 1991 Pinatubo eruption every 2 y, with consequent implications for stratospheric ozone. We project changes in storm frequencies using a temperature-dependent generalized extreme value statistical model calibrated by historical storm surges and observed temperatures since 1923. The number of storm surge events as big as the one caused by the 2005 Katrina hurricane are reduced by about 50% compared with no geoengineering, but this reduction is only marginally statistically significant. Nevertheless, when sea level rise differences in 2070 between the RCP4.5 and geoengineering are factored into coastal flood risk, we find that expected flood levels are reduced by about 40 cm for 5-y events and about halved for 50-y surges.

Evaluation of Incidental Findings on Abdominopelvic CT: Potential Benefit of Photon-counting Detector CT Over Conventional Single-energy CT.

PURPOSE: To assese of potential benefint of photon-counting detector CT (PCD-CT) over conventional single-energy CT (CSE-CT) on accurate diagnosis of incidental findings with high clinical significance (IFHCS). MATERIALS AND METHODS: This retrospective study included 365 patients who initially underwent abdominopelvic contrast-enhanced CT (AP-CECT) without non-enhancement (PCD-CT: 187 and CSE-CT: 178). We selected IFHCS and evaluated their diagnosability using CE-CT alone. IFHCSs that could not be diagnosed with only CE-CT were evaluated using additional PCD-CT postprocessing techniques, including virtual non-contrast image, low keV image, and iodine map. A PCD-CT scanner (NAEOTOM Alpha, Siemens Healthineer, Erlangen, Germany) was used. RESULTS: Thirty-nine IFHCSs (PCD-CT: 22 and CSE-CT: 17) were determined in this study. Seven IFHCSs in each group were able to diagnose with only CE-CT. Fifteen IFHCSs were able to diagnose using the additional PCD-CT postprocessing technique, which was useful for detecting and accurately diagnosing 68.2% (15/22) of lesions and 65% (13/20) of patients. All IFHCSs were accurately diagonosed with PCD-CT. CONCLUSION: PCD-CT was useful for characterizing IFHCSs that are indeterminate at CSE-CT. PCD-CT offered potential benefit of PCD-CT over conventional single-energy CT on evaluation of IFHCS on only abdominopelvic CT.

Impact of Selenium Deficiency on Clinical Outcomes in Newly Diagnosed Heart Failure Patients in Japan.

Previous studies conducted have reported higher mortality and heart failure readmission rates in heart failure patients with selenium deficiency. However, these studies included patients with advanced heart failure, which may have confounded the relationship between selenium deficiency and heart failure pathology. This study aimed to explore the clinical characteristics and outcomes of heart failure patients with selenium deficiency who were newly diagnosed and hospitalized for heart failure in Japan. A total of 256 patients, who were admitted to our hospital for the first time due to heart failure, were included in this study. The patients were divided into two groups: a low selenium group (LS group, n=132) and a normal selenium group (NS group, n=124). Clinical features and outcomes were compared between the two groups, including 1-y mortality and readmissions due to heart failure. Among the patients admitted with heart failure, 51.6% exhibited selenium deficiency. The LS group showed a higher proportion of females (65.4% vs. 46.4%, p=0.003) and lower albumin levels (3.2±0.5 g/dL vs. 3.5±0.5 g/dL, p<0.001) compared to the NS group. The LS group had a significantly higher readmission rate for heart failure (31.8% vs. 17.7%, p=0.009). Multivariate analysis revealed heart failure patients with low selenium as an independent factor for readmission due to heart failure. Newly diagnosed heart failure patients with low selenium demonstrated a high readmission rate for heart failure.

Usefulness of Balloon-Assisted Ultrasound-Guided Percutaneous Thrombin Injection to Femoral Artery Pseudoaneurysm by Transradial Artery Approach.

Balloon-Assisted Ultrasound-Guided Percutaneous Thrombin Injection (BATI) is useful for iatrogenic pseudoaneurysm. In previous reports, BATI for pseudoaneurysm of the femoral artery was performed by contralateral transfemoral approach. It has been reported that patients with obesity, hypertension, and diabetes have more hemorrhagic complications at the puncture site of the femoral artery. We report a case in which BATI by transradial artery approach was useful for patients with obesity, hypertension, and diabetes who were expected to be at high risk of hemorrhagic complications of transfemoral artery approach.

The Impact of Multidisciplinary Approaches to Social Functioning on Surgical Outcomes After Surgery for Cervical Myelopathy.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: To identify the effects of multidisciplinary approaches (MAs) to improve social functioning (SF) on 1-year surgical outcomes in patients with cervical myelopathy. SUMMARY OF BACKGROUND DATA: Despite significant improvement in cervical myelopathy, a patient's quality of life (QOL) sometimes does not improve postoperatively. A previous study revealed that SF, rather than myelopathy severity, correlated with QOL improvement after decompression surgery for cervical myelopathy. PATIENTS AND METHODS: This study compared two prospective cohorts in Japan. Patients who underwent cervical laminoplasty for cervical myelopathy from 2018 to 2020 were enrolled in the control cohort. Patients who underwent the same surgery with the same indications between 2020 and 2021 were enrolled in the MA cohort. Patients in the control cohort were treated with a standard care protocol, and those in the MA cohort were treated with a multidisciplinary protocol that focused on SF improvement. The changes in the total Japanese Orthopedic Association (JOA) score and in the domains of the JOA scores (upper limb function, lower limb function, upper limb sensory, and lower limb sensory) from preoperatively to 1 year postoperatively were compared between the control and MA cohorts using a mixed-effect model. RESULTS: The control and MA cohorts comprised 140 and 31 patients, respectively. The improvement in the JOA score was significantly better in the MA cohort than in the control cohort ( P = 0.040). In analyses of each JOA score domain, the improvement of upper limb function was significantly better in the MA cohort than in the control cohort ( P = 0.033). Similarly, the MA cohort demonstrated significantly higher patient-reported outcomes for upper extremity function than the control cohort ( P < 0.001). In addition, the self-care domain of QOL score at 1 year postoperatively was significantly higher in the MA cohort than in the control cohort ( P = 0.047). CONCLUSION: MAs to improve/rebuild a patient's SF were effective in improving cervical myelopathy and the self-care domain of QOL. This study is the first to demonstrate the effectiveness of postoperative MAs in patients with cervical myelopathy. LEVEL OF EVIDENCE: Level 3.

Distal transradial artery access for vascular access intervention.

BACKGROUND: Vascular access intervention is a useful treatment method for maintaining arteriovenous fistula (AVF) in dialysis patients. The outflow vein is commonly used as the access site for vascular access intervention. In cases where it is difficult to puncture veins due to multiple lesions or poor AVF development, vascular access intervention is performed using the radial artery. However, it is difficult to perform a vascular access intervention with radial artery access to the AVF in the distal forearm. We reported the efficacy and safety of vascular access intervention with distal transradial artery access (dTRA). CASE SERIES: We have been conducting vascular access intervention with dTRA access since January 2019. We evaluated complications and procedure time for 12 cases of vascular access intervention with dTRA access performed from January to December 2019.The success rate of the procedure was 100% and no puncture hemorrhagic complication was observed in 12 cases performed at our institution. No radial artery occlusion was observed in 12 cases. The average fluoroscopy time was 11.5 min and the average contrast volume was 41 ml. CONCLUSION: dTRA for vascular access intervention has advantages over conventional radial artery access in terms of safety of the procedure and ease of hemostasis.

Sublinear diffusion in the generalized triangle map.

Diffusion of the orbits in a nonchaotic area-preserving map called a generalized triangle map (GTM) is numerically and analytically investigated. We provide accurate empirical evidence that the mean-squared displacement of the momentum for generic perturbation parameter settings increases sublinearly in time, and that the distribution of the momentum obeys a time-fractional diffusion equation. We show that the diffusion properties in the GTM do not follow any of the known stochastic processes generating sublinear diffusion since two seemingly incompatible features, non-Markovian yet stationary, coexist in the dynamics.

Exploration and structure-based engineering of alkenal double bond reductases catalyzing the CαCß double bond reduction of coniferaldehyde.

Lignin, a complex aromatic polymer, represents a significant obstacle in lignocellulosic biomass utilization. The polymerization of lignin occurs by radical couplings, which mainly form ether and C-C bonds between monolignol units. The chemical stability of these bonds between monolignol units causes the recalcitrant nature of lignin. Since the Cα-Cß double bond in the monolignols is a crucial chemical feature for the radical coupling, reduction of the double bond would decrease the degree of lignin polymerization, avoiding the recalcitrance of lignin. To develop a method of lignin engineering, we have focused on alkenal double bond reductases (DBR), which can reduce the Cα-Cß double bond of a monolignol precursor. Here, a novel bacterial DBR from Parvibaculum lavamentivorans DS-1 (PlDBR) was found. This enzyme can reduce the side-chain double bond of coniferaldehyde (CALD) and has a 41% amino-acid sequence identity with CALD DBR from Arabidopsis thaliana (AtDBR). The crystal structure of the PlDBR showed that it has a larger substrate-binding pocket than AtDBR, conferring broader substrate specificity on the former. Structural and mutation analyses of PlDBR and AtDBR suggested that Tyr51 and Try252 are critical residues for the catalytic activity of PlDBR. In addition, Tyr81 of AtDBR appears to cause substrate inhibition. Replacing Tyr81 of AtDBR with a smaller amino-acid residue, as in the AtDBR variants Tyr81Leu and Tyr81Ala, resulted in a substantially higher CALD-reducing activity compared to the wild type. These variants would be promising candidates for lignin manipulation to decrease the recalcitrance of lignocellulosic biomass.

Thermal and photoinduced electron transfer reactions of phthalocyanine complexes of Zn(II) and Cu(II) in acetonitrile.

Phthalocyanine that has four peripheral 2-methoxyphenyl substituents at the α-position and its Zn(II) and Cu(II) complexes were synthesized. Chemical oxidation by the Cu(II) ion and electrochemical oxidation of these metal complexes were investigated spectrophotometrically in acetonitrile. The UV-visible absorption spectra of these metal complexes and their one-electron oxidized π-cation radicals showed no concentration dependence, indicating that these species exist as monomers in solution. Kinetics of the thermal electron transfer reaction from each phthalocyanine complex to Cu2+ and the photoinduced electron transfer reaction of the Zn(II) phthalocyanine complex with V(V) and V(IV) Schiff base complexes were studied using conventional spectrophotometric and transient absorption techniques, and the electron transfer rate constants were analysed using the Marcus cross relationship. The obtained rate constants of the electron self-exchange reaction between the parent phthalocyanine complexes and their π-cation radicals were in the order of 109 to 1011 M-1 s-1 at T = 298.2 K. These large electron self-exchange rate constants are consistent with the phthalocyanine-centred redox reactions where small reorganization energies are required with little structural change during the electron transfer process.

Usefulness of buddy-wire anchoring technique in cases where deep insertion of guide extension catheter is difficult.

Guide extension catheters are useful in PCI procedures when device passage is difficult. However, in complex lesions, such as severely tortuous vessels, deep insertion of the guide extension catheter cannot always be achieved even when balloon anchoring technique is applied. In such cases, in our hospital, a guidewire is added as a buddy wire and the balloon anchoring technique is applied. The advantage of this method is that the anchoring force is strengthened by anchoring another wire with the wire. By pulling the wire that has been anchored with a balloon, anchoring force is fortified, enabling deep insertion of the guide extension catheter and subsequent stent delivery. This method, which we refer to as the Buddy-wire anchoring technique, can be useful in cases of complex lesions, especially those with severely tortuous vessels, where device passage is difficult. Here we report on the Buddy-wire anchoring technique (Fig. 1). Fig. 1 a Cine image showing Buddy-wire anchoring technique. The black arrow indicated the tip of the guide extension catheter. The red arrow indicated the balloon which anchoring the wire. b Schema showing Buddy-wire anchoring technique.

Serum uric acid level is associated with reperfusion ventricular arrhythmias in acute myocardial infarction.

BACKGROUND AND AIM: In the acute phase of acute myocardial infarction (AMI), reperfusion ventricular arrhythmias such as ventricular tachycardia and ventricular fibrillation (Reperfusion VT/VF) resulting from reperfusion injury are one of the causes of in-hospital death. Predicting Reperfusion VT/VF is clinically important. Previous studies have reported that oxidative stress is the cause of reperfusion injury and reperfusion arrhythmia. There are also reports that xanthine oxidase inhibitors have the effect of preventing reperfusion arrhythmia. We hypothesized that hyperuricemia is a risk factor for reperfusion arrhythmias in AMI. The aim of our study is to investigate whether serum uric acid is associated with Reperfusion VT/VF in acute myocardial infarction. METHOD: This is a single-center, retrospective cohort study. We enrolled 612 ST elevation myocardial infarction patients who underwent successful primary percutaneous coronary intervention (PCI). We divided patients into a high serum uric acid group (HUA group) and a low serum uric acid group (LUA group) with a cutoff value of 7.0 mg/dl, which is the standard value of serum uric acid. We compared the frequency of Reperfusion VT/VF in both groups. RESULT: There were 111 patients in the HUA group and 512 patients in the LUA group. Creatinine tended to be higher in the HUA group than in the LUA group. (1.12 ± 0.41 mg/dl VS 0.92 ± 1.10 mg/dl P = 0.06). The frequency of Reperfusion VT/VF was significantly higher in the HUA group than in the LUA group (17.1% VS 4.0% P < 0.001). CONCLUSION: Elevated serum uric acid is associated with higher frequency of reperfusion ventricular arrhythmia.

Efficacy of Long Inflation Balloon Angioplasty for Acute Myocardial Infarction Due to Thrombotic Lesions.

BACKGROUND: Distal embolism is a frequent complication in percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) due to thrombotic lesions. Distal embolism causes no reflow phenomenon, which leads to worse patient prognosis after AMI. There is no established treatment to prevent distal embolism in PCI for thrombotic lesions. The aim of this study is to investigate the usefulness of long inflation balloon angioplasty (LIBA) with perfusion balloon in PCI for AMI due to thrombotic lesions. METHODS AND RESULTS: This is a case series study. We investigated 10 cases treated with LIBA for cases with massive thrombus remaining after thrombus aspiration therapy in primary PCI for acute myocardial infarction. We investigated the success rate of the procedure, residual stenosis rate, TIMI flow grade, TIMI frame count, and myocardial blush score in 10 cases of primary PCI with LIBA at our hospital. In all 10 cases, distal embolism was not observed by angiogram after LIBA. In 9 cases, residual stenosis was improved to less than 25% and the procedure was completed without a stent. Before PCI, all cases had TIMI flow grade 0, but in all 10 cases, TIMI flow grade 3 was obtained after PCI. The mean TIMI frame count was 19.6 ± 2.50 for RCA lesions and 27.5 ± 1.5 for LAD lesions. Regarding myocardial blush score, grade 3 was obtained in 8 cases and grade 2 was obtained in 2 cases. CONCLUSION: LIBA using a perfusion balloon is a useful technique in thrombus lesion to prevent distal embolism.

Clinical features of ST-segment elevation myocardial infarction in patients receiving welfare public assistance in urban area of Japan.

BACKGROUND: An increase in the rate of relative poverty and the number of welfare recipients is a serious social problem in Japan. A recent overseas survey demonstrated that lack of health insurance was associated with increased in-hospital mortality in patients with ST-segment elevation myocardial infarction (STEMI). The aim of this study is to investigate the clinical features of STEMI patients who receive welfare public assistance in Japan. METHODS: We enrolled 525 STEMI patients who were hospitalized in our hospital from 2010 to 2019. We divided patients into groups of patients receiving welfare public assistance (WPA group, N = 67) and groups of patients not receiving welfare public assistance (non-WPA group, N = 458). Patient characteristics, clinical outcome, and cardiac function on transthoracic echocardiography were compared. RESULTS: WPA group were younger than non-WPA group (61.2 ± 10.9 years VS 64.5 ± 13.3 years, p = 0.03). The prevalence of smoking was higher in WPA group compared to non-WPA group (91.0% VS 81.1% p = 0.04) and high-density lipoprotein cholesterol value of WPA group was lower than in non-WPA group (43.2 ± 9.9 mg/dl vs 47.1 ± 12.8 mg/dl, p = 0.005). Ventricular arrhythmia on admission was significantly more frequent in WPA group (11.9% VS 4.8%, p = 0.02). In acute and chronic phase, left ventricular ejection fraction in WPA group was lower than non-WPA group (in acute phase 46.6 ± 10.7% vs 53.3 ± 8.6% p = 0.001, in chronic phase 48.7 ± 10.1% vs 55.3 ± 9.4%, p = 0.008). CONCLUSION: STEMI patients receiving welfare public assistance had poorer control of coronary risk, increased risk of fatal arrhythmia, and reduced systolic function than those not receiving welfare public assistance. It is necessary to have a system that can strengthen lifestyle management, such as diet and smoking cessation for the purpose of improving the prognosis of welfare recipients after AMI.

Impending rupture of abdominal aortic aneurysm due to apixaban use.

Direct oral anticoagulants (DOAC) are useful for preventing embolism and venous thrombosis in patients with atrial fibrillation. There are also reports that DOAC can dissolve existing intracardiac thrombus. Here, we report a case in which DOAC lysed a thrombus in an abdominal aortic aneurysm (AAA), resulting in impending rupture of the AAA. An 85-year-old woman was admitted to our hospital with a diagnosis of congestive heart failure. She has had atrial fibrillation and started taking DOAC. Computed tomography (CT) performed on admission revealed an AAA with a large amount of intraluminal thrombus (ILT). Fifty days after the start of DOAC, she visited our hospital with the chief complaint of severe abdominal pain. CT showed no enlargement of the AAA, but the ILT in the AAA had dissolved. She was diagnosed with an impending rupture of an AAA. She underwent emergency aortic replacement with a Y-shaped vascular prosthesis. When using DOAC in patients with aortic aneurysms with ILT, we need to be aware of the risk of the thrombus dissolving. .

Influence of arm position on proton density fat fraction in the liver using chemical shift-encoded magnetic resonance imaging.

PURPOSE: To evaluate the influence of arm position on B1 and proton density fat fraction (PDFF) in the liver using chemical shift-encoded magnetic resonance imaging. MATERIALS AND METHODS: Participants were 8 healthy volunteers without liver disease and 36 patients with presumed or proven fatty liver. We assessed two preliminary examinations in healthy subjects, i.e., arm position influence on B1 and the variability of the PDFF between two scans within a short period of time. To verify the changes in PDFF measurement, 36 patients with fatty liver were conducted to compare 2 different arm positions-the elevated arms and side arms positions. The measurement location was based on the Healey & Schroy classification. The Wilcoxon test was used to analyze the difference in B1 in between the elevated arms and side arms positions. The Bland-Altman analysis was used to assess the agreement between two measurements of PDFF: two same scans within a short period of time, and two scans with different arms positions. RESULTS: B1 was significantly different in all segments except for medial segment. The variability of the PDFF between two scans within a short period of time was small in all segments. Some patients had large fluctuations in all segments, although the mean differences in PDFF were small. Upper and lower limits of agreement were 2.064% to 2.871% and - 2.430% to -1.462%, respectively. The relative difference in the rate of PDFF changes as the median (interquartile range [IQR]) in the lateral, medial, anterior, and posterior segments between both the arms positions were 0.0% (9.4), 1.1% (7.3), 1.5% (8.2) and - 0.2% (10.3), respectively. CONCLUSIONS: Arm position can significantly affect B1 and PDFF in the liver. Although the absolute change in PDFF between arm positions was not so large, the difference in arm positions can cause large relative PDFF fluctuations.