Publications by authors named "Atsushi Higaki"

Purpose: To investigate the utility of qualitative and semi-quantitative evaluation of DCE-MRI for detecting clinically significant prostate cancer (csPC).

Methods: This retrospective study analyzed 307 lesions in 231 patients who underwent 3.0T MRI.

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Purpose: To compare image quality and diagnostic performance among SS-EPI diffusion weighted imaging (DWI), multi-shot (MS) EPI DWI, and reduced field-of-view (rFOV) DWI for muscle-invasive bladder cancer (MIBC).

Materials And Methods: This retrospective study included 73 patients with bladder cancer who underwent multiparametric MRI in our referral center between August 2020 and February 2023. Qualitative image assessment was performed in 73; and quantitative assessment was performed in 66 patients with maximum lesion diameter > 10 mm.

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Objective: The aim of this study was to assess the prevalence of peritumoral enhancement (PTE) in patients with muscle-invasive bladder cancer (MIBC) and non-MIBC (NMIBC) and to propose a modified diagnostic criterion for Vesical Imaging Reporting and Data System (VI-RADS) that incorporates PTE.

Materials And Methods: This retrospective study included 95 patients with bladder cancer (age, 72 ± 11; 77 men; 36 MIBCs and 59 Non-MIBCs) who underwent multiparametric MRI in our referral center between 2011 and 2023. The images were interpreted by four radiologists.

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The Vesical Imaging-Reporting and Data System (VI-RADS) is a standard magnetic resonance imaging (MRI) and diagnostic method for muscle-invasive bladder cancer that was published in 2018. Several studies have demonstrated that VI-RADS has high diagnostic power and reproducibility. However, reading VI-RADS requires a certain amount of expertise, and radiologists need to be aware of the various pitfalls.

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A woman in her sixties with portosystemic shunt and hepatic encephalopathy underwent open mesenteric vein ligation, resulting in improved portal flow and blood ammonia. In this case, 4D flow MRI was a valuable diagnostic and follow-up tool, visualizing and quantifying physiological portal hemodynamics with features distinct from those of contrast-enhanced CT and digital subtraction angiography. Our case study highlights the value of 4D flow MRI for managing portosystemic shunts.

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Purpose: This study aimed to assess whether short repetition time (TR) diffusion-weighted imaging (DWI) could improve diffusion contrast in patients with prostate cancer (PCa) compared with long TR (conventional) reference standard DWI.

Materials And Methods: Our Institutional Review Board approved this retrospective study and waived the need for informed consent. Twenty-five patients with suspected PCa underwent multiparametric magnetic resonance imaging (mp-MRI) using a 3.

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Article Synopsis
  • The study focused on understanding the clinical behaviors and imaging characteristics of unclassified renal cell carcinoma (RCC) using CT and MRI scans in 10 patients.
  • It evaluated factors like tumor size, growth patterns, postoperative recurrence, and survival rates alongside imaging features such as CT density and internal appearance.
  • Results showed that larger tumors with heterogeneous interiors and cystic degeneration were common, with significant differences in growth patterns and recurrence rates between patients who did and did not experience recurrence post-surgery.
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Objective: To evaluate the relationships between hemoglobin A1c (HbA1c) levels with exocrine pancreatic function using cine-dynamic magnetic resonance cholangiopancreatography (MRCP) and the pancreatic parenchyma using fat-suppressed T1 mapping and the proton density fat fraction (PDFF).

Methods: Patients who underwent 3T-MRI and HbA1c measurement were retrospectively recruited. MRI included cine-dynamic MRCP with a spatially selective inversion-recovery (SS-IR) pulse, fat-suppressed Look-Locker T1 mapping and multiecho 3D Dixon-based PDFF mapping.

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Catheterization of the right adrenal vein (rt.AdV) to obtain blood samples can often be difficult. The aim of the present study was to investigate whether blood sampling from the inferior vena cava (IVC) at its juncture with the rt.

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Purpose: The mechanisms underlying the morphological changes in liver cirrhosis remain unknown. This study aimed to clarify the relationship between fibrotic hepatic morphology and portal hemodynamic changes using four-dimensional flow magnetic resonance imaging (MRI).

Materials And Methods: Overall, 100 patients with suspected liver disease who underwent 3-T MRI were evaluated in this retrospective study.

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Objective: To evaluate time-dependent changes in hepatic extracellular volume (ECV) fraction using contrast-enhanced CT (CECT) and serological liver fibrosis markers, the fibrosis-4 (FIB-4) index and aspartate aminotransferase to platelet ratio index (APRI), before and after direct-acting antiviral therapy (DAA) for hepatitis C virus (HCV) infection.

Methods: 41 HCV-infected patients who achieved sustained virological response (SVR) after DAA (SVR group) and 10 control patients (untreated or unresponsive to treatment) who underwent CECT and serum biochemical tests before or after the first examination/DAA (T1) and at intervals thereafter (T2:<6 months after T1, T3: at 6-12 months, T4: at 12-24 months, and T5:>24 months) were evaluated.

Results: In the control group, ECV fractions remained relatively unchanged through the study, and significant differences in FIB-4 index comparisons and APRI comparisons were only seen between the T2 and T4 values ( = 0.

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Purpose: To identify predictive factors for truncation artifacts (TAs) in the arterial phase of Gd-EOB-DTPA-enhanced MRI in a multicenter study in Japan.

Materials And Methods: Data on patient factors (age, sex, weight, presence of viral hepatitis, and other conditions) and imaging parameters (e.g.

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Purpose: To determine whether LI-RADS ancillary features predict longitudinal LR-3 observation category changes.

Materials And Methods: This exploratory, retrospective, single-center study with an independent reading center included patients who underwent two or more multiphase CT or MRI examinations for hepatocellular carcinoma assessment between 2011 and 2015. Three readers independently evaluated each observation using CT/MRI LI-RADS v2017, and observations categorized LR-3 using major features only were included in the analysis.

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Purpose: To develop and evaluate the performance of a fully-automated convolutional neural network (CNN)-based algorithm to evaluate hepatobiliary phase (HBP) adequacy of gadoxetate disodium (EOB)-enhanced MRI. Secondarily, we explored the potential of the proposed CNN algorithm to reduce examination length by applying it to EOB-MRI examinations.

Methods: We retrospectively identified EOB-enhanced MRI-HBP series from examinations performed 2011-2018 (internal and external datasets).

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Background: Liver alignment between series/exams is challenged by dynamic morphology or variability in patient positioning or motion. Image registration can improve image interpretation and lesion co-localization. We assessed the performance of a convolutional neural network algorithm to register cross-sectional liver imaging series and compared its performance to manual image registration.

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Purpose To identify biochemical factors associated with liver enhancement over time on gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance (MR) images and predict the optimal time point of the hepatobiliary phase in various clinical settings. Materials and Methods This study was approved by the institutional review boards, and written informed consent was obtained from the 1903 patients enrolled. Simple and multiple logistic regression analyses were performed to investigate the biochemical factors associated with liver-to-spleen contrast (LSC) of at least 1.

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Aim: To clarify the clinical and magnetic resonance imaging (MRI) features of de novo hypervascular hepatocellular carcinoma (HCC) using serial gadoxetic acid-enhanced MRI.

Methods: The institutional review board approved this retrospective study. After review of 1007 MRI examinations in 240 patients with chronic liver disease, 17 newly developed hypervascular HCCs in 16 patients detected by follow-up from initial MRI examination without hepatocellular nodules were evaluated.

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Purpose: To evaluate the influence of oral ingestion on the secretory flow dynamics of physiological pancreatic juice within the main pancreatic duct in healthy subjects by using cine-dynamic MRCP with spatially-selective inversion-recovery (IR) pulse non-invasively.

Materials And Methods: Thirty-eight healthy subjects were investigated. MRCP with spatially-selective IR pulse was repeated every 15 s for 5 min to acquire a total of 20 images (cine-dynamic MRCP).

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Background: It remains unknown whether Kupffer-phase images in Sonazoid-enhanced ultrasonography (US) can be used to predict hypervascularization of borderline lesions. Therefore, we aimed to clarify whether Kupffer-phase images in Sonazoid-enhanced ultrasonography can predict subsequent hypervascularization in hypovascular borderline lesions detected on hepatobiliary-phase gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging.

Methods: From January 2008 to March 2012, 616 low-intensity hypovascular nodules were detected in hepatobiliary-phase images of Gd-EOB-DTPA-enhanced MRI at nine institutions.

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Purpose: To determine the clinical, histopathologic and imaging features of pancreatic adenocarcinomas without secondary signs on dynamic CT.

Materials And Methods: Seventy patients (mean age 70 years) with histologically proven pancreatic adenocarcinoma underwent preoperative contrast material-enhanced multiphasic multidetector CT before pancreatic resection. In each patient, clinical data including carbohydrate antigen 19-9, frequency of isoattenuating tumours, and presence of secondary signs and histopathologic findings such as tumour location, tumour stage, and microscopic infiltrative growth grade were evaluated.

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Purpose: To investigate the feasibility of noncontrast-enhanced cine dynamic magnetic resonance cholangiopancreatography (MRCP) with a spatially selective inversion-recovery (IR) pulse for evaluating exocrine pancreatic function in comparison with the N-benzoyl-L-tyrosyl-p-aminobenzoic acid (BT-PABA) test as a pancreatic exocrine function test.

Materials And Methods: Twenty subjects with or without chronic pancreatitis were included. MRCP with a spatially selective IR pulse was repeated every 15 seconds for 5 minutes to acquire a total of 20 images (cine-dynamic MRCP).

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The aim of this study was to evaluate the process of biliary excretion of gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) into the biliary tract and to assess the accumulation patterns in the gallbladder using MR cholangiography obtained with Gd-EOB-DTPA which is a liver-specific hepatobiliary contrast agent. Seventy-five patients underwent Gd-EOB-DTPA enhanced MR imaging. Serial multiphasic hepatobiliary phase imaging was qualitatively reviewed to evaluate the process of the biliary excretion of contrast agent into the bile duct and the gallbladder.

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Purpose: This study was undertaken to quantify tissue gadolinium (Gd) deposition in hepatorenally impaired rats exposed to gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) by means of inductively coupled plasma mass spectrometry (ICP-MS) and to compare differences in Gd distribution among major organs as possible triggers for nephrogenic systemic fibrosis.

Materials And Methods: Five hepatorenally impaired rats (5/6-nephrectomized, with carbon-tetrachloride-induced liver fibrosis) were injected with Gd-EOB-DTPA. Histological assessment was conducted and Gd content of the skin, liver, kidneys, lungs, heart, spleen, diaphragm, and femoral muscle was measured by inductively coupled plasma mass spectrometry (ICP-MS) at 7 days after last injection.

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Hypovolemic shock is often seen in patients with severe blunt trauma who have suffered from blood circulation inadequate to maintain oxygen delivery to multiple organs. The early recognition and prompt management of hypovolemic shock in patients with multiple injuries are mandatory to improving prognosis and patient conditions. The diagnostic accuracy of computed tomography (CT) as a primary diagnostic tool is well established.

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