Publications by authors named "Shigeo Okuda"

Article Synopsis
  • Retroperitoneal leiomyosarcoma (RPLMS) is an uncommon tumor that typically appears as a significant abdominal mass and may present vague symptoms.
  • In a reported case, RPLMS was mistaken for an adnexal tumor in a woman, highlighting the challenges in diagnosis due to similar radiological features.
  • The distinction was made by identifying the right ovarian vein, which passed through the tumor without a direct connection, emphasizing the need to recognize vascular structures to differentiate between these conditions.
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Background: The clinical importance of positive peritoneal cytology results in patients with pancreatic ductal adenocarcinomas remains controversial. We evaluated the prognosis of these patients and the predictive preoperative risk factors for positive peritoneal cytology results.

Methods: We retrospectively reviewed patients who underwent curative-intent surgery at our institution between May 2010 and June 2020.

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Cardiac magnetic resonance imaging (CMR) often shows discrepancies between right ventricular outflow tract (RVOT) flow and left ventricular outflow tract flow in patients with late-stage repaired tetralogy of Fallot (rTOF), leading to potential errors in pulmonary regurgitation fraction (PRF) assessment. This study aimed to identify the conditions under which RVOT flow can be acutely evaluated using four-dimensional (4D) flow CMR. Twenty-seven consecutive patients with rTOF underwent both two-dimensional phase-contrast (2D PC) and 4D flow CMR between 2016 and 2018, excluding those with peripheral pulmonary artery stenosis, RVOT conduit replacement, unknown surgical method, and an aortic valve regurgitation greater than 20%.

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Three-dimensional (3D) magnetic resonance elastography (MRE) is more accurate than two-dimensional (2D) MRE; however, it requires long-term acquisition. This study aimed to reduce the acquisition time of abdominal 3D MRE using a new sample interval modulation (short-SLIM) approach that can acquire all three motions faster while reducing the prolongation of echo time and flow compensation. To this end, two types of phantom studies and an in vivo test of the liver in three healthy volunteers were performed to compare the performances of conventional spin-echo echo-planar (SE-EPI) MRE, conventional SLIM and short-SLIM.

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Purpose: The postoperative mortality rate of distal pancreatectomy is lower than that of pancreaticoduodenectomy, although persistent complications may occur after distal pancreatectomy. Fluid collection (FC) is frequently observed after distal pancreatectomy; however, FC may occasionally progress to postoperative intra-abdominal abscess (PIAA), which requires conservative or progressive interventional treatment. This study aimed to compare the status between patients with or without PIAA, identify predictive factors for PIAA and clinically relevant postoperative pancreatic fistula, and investigate the clinical characteristics of patients with PIAA with interventional drainage.

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Purpose: This study aimed to facilitate research progress in MR elastography (MRE) by providing a versatile and convenient application for MRE reconstruction, namely the MRE research tool (MRE-rTool). It can be used for a series of MRE image analyses, including phase unwrapping, arbitrary bandpass and directional filtering, noise assessment of the wave propagation image (motion SNR), and reconstruction of the elastogram in both 2D and 3D MRE acquisitions. To reinforce the versatility of MRE-rTool, the conventional method of motion SNR was modified into a new method that reflects the effects of image filtering.

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Due to the invasiveness of sample collection, treatment for an abscess in the pelvis, such as a gynecological abscess, is often started without a culture test. A test that could predict the appropriate antibiotic and clinical course without invasiveness prior to treatment initiation would be useful. Magnetic resonance spectroscopy (MRS) can be used to detect metabolites in an abscess and has the potential for evaluation of gynecological abscesses.

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Article Synopsis
  • Bi-parametric magnetic resonance imaging (bpMRI) is effective for diagnosing clinically significant prostate cancer (csPCa), but it has more false negatives for PI-RADS category 3 lesions compared to multiparametric MRI (mpMRI) with dynamic-contrast-enhanced imaging (DCE-MRI).
  • A study involving 105 patients tested synthetic MRI with relaxometry maps against traditional bpMRI and its ability to diagnose csPCa, using histopathological results as a reference.
  • The findings revealed that synthetic bpMRI's diagnostic performance was similar to conventional bpMRI and DCE-MRI, suggesting its potential as a contrast media-free option for evaluating csPCa.
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Purpose: To assess the impact of the updated Bosniak classification (BC2019) for cystic renal masses (CRMs) on interobserver agreement between radiologists and urologists and the diagnostic value of adding MRI to CT examination (combined CT/MRI).

Method: This study included 103 CRMs from 83 consecutive patients assessed using contrast-enhanced CT and MRI between 2010 and 2016. Nine readers in three groups (three radiologists, three radiology residents, and three urologists) reviewed CT alone and the combined CT/MRI using BC2019.

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Background: The development of ultra-high-resolution CT (U-HRCT) is expected to improve the accuracy of coronary stenosis evaluation. This study aimed to evaluate the accuracy of the stenosis severities of coronary artery phantoms estimated using U-HRCT by comparing them to those estimated with conventional CT.

Methods: Coronary artery phantoms with non-calcified and calcified lesions were scanned with conventional CT (64-row ​× ​0.

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This study aims to develop and assess a new automated processing technique in MR elastography (MRE), namely coherent-wave auto-selection (CHASE). CHASE enables automatic selection of the region of interest (ROI) for stiffness measurement by extraction of the coherent wave region (CHASE ROI), and it improves the reconstruction of stiffness by a directional filter oriented along the main wave in each pixel (CHASE filtering). In this study, MRE of a phantom and of the liver of four healthy volunteers was performed.

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Objective: Dermal backflow (DBF) and reduced lymphatic visualization are common findings of lymphedema on various imaging modalities. However, there is a lack of knowledge about how these findings vary with the anatomic location and severity of lymphedema, and previous reports using indocyanine green lymphography or lymphoscintigraphy show variable results. Magnetic resonance lymphangiography (MRL) is expected to clarify this clinical question due to its superior ability for lymphatic visualization.

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Article Synopsis
  • The study aimed to assess whether texture analysis of apparent diffusion coefficient (ADC) maps can effectively differentiate fat-poor angiomyolipomas (fpAMLs) from non-clear-cell renal cell carcinomas (non-ccRCCs) using MRI data from two institutions.
  • Involving 106 patients with confirmed renal masses, researchers extracted 45 texture features and used a random forest model to analyze the data, comparing its diagnostic performance with that of experienced and novice radiologists.
  • The texture analysis showed similar accuracy to experienced radiologists in distinguishing between fpAMLs and non-ccRCCs, indicating its feasibility as a reliable diagnostic tool across different imaging technologies and institutions.
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Article Synopsis
  • - The shortage of donor hearts creates challenges for cardiac transplants in advanced heart failure patients, leading to a demand for regenerative therapies.
  • - Human induced pluripotent stem cells (hiPSCs) show promise in generating cardiomyocytes that could aid heart recovery, but issues like teratoma formation and scaling production need addressing for clinical use.
  • - This study successfully combined pure cardiac spheroids with gelatin hydrogel to improve heart function and developed a transplantation strategy with a device for these regenerative cardiomyocytes.
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Article Synopsis
  • The study aimed to evaluate the effectiveness of computed diffusion-weighted imaging (cDWI) in assessing primary prostate cancer (PCa) using biparametric whole-body MRI (bpWB-MRI).
  • Researchers compared the diagnostic performance of different MRI datasets, including conventional pelvic MRI and various bpWB-MRI formats, with systemic biopsy as the reference standard.
  • Results indicated that computed bpWB-MRI performed similarly to dedicated pelvic bpMRI, suggesting cDWI could enhance standard whole-body MRI protocols for better detection of both primary and metastatic PCa.
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In the 2016 World Health Organization renal tumor classification, the mixed epithelial and stromal tumor family was introduced as a new entity. This family encompasses a spectrum of tumors, ranging from predominantly cystic tumors (adult cystic nephromas) to tumors that are variably solid (mixed epithelial and stromal tumors). The majority of previous studies incorporating "mixed epithelial and stromal tumor" in the titles were actually reports of imaging findings of adult cystic nephroma.

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Background: Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is a biopsy technique widely used to diagnose pancreatic tumors because of its high sensitivity and specificity. Although needle-tract seeding caused by EUS-FNA has been recently reported, dissemination of pancreatic cancer cells is generally considered to be a rare complication that does not affect patient prognosis. However, the frequency of dissemination and needle-tract seeding appears to have been underestimated.

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Objective: To optimize prediction for intestinal invasion of epithelial ovarian cancer. It is important to achieve debulking surgery to improve prognosis in ovarian cancer; intestinal resection is adopted if the cancer is invaded and resectable, but the preoperative evaluation method of intestinal invasion is still controversial.

Methods: Patients (n = 174) who underwent primary debulking surgery for epithelial ovarian cancer were recruited for retrospective study; 28 and 146 patients were classified into the invasion and non-invasion groups, whether they needed intestinal resection or not.

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Article Synopsis
  • The study aimed to analyze the MRI features and staging of neuroendocrine carcinoma (NEC) of the uterine cervix, while also examining the relationship between pathology and survival rates.
  • Findings indicated that most cases showed a slightly high signal intensity and restricted diffusion in MRI scans, with a high overall accuracy of 88% for staging when compared to pathology results.
  • The research revealed that fewer patients with advanced stages (III and IV) had favorable survival outcomes, with significant recurrence rates observed during the follow-up period.
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Serous cystic neoplasms are relatively uncommon and rarely possess malignant potential. We report a rare case of pancreatic serous cystadenoma with splenic invasion in a female in her 60s. Dynamic contrast-enhanced CT revealed a 3 cm mass in the tail of the pancreas.

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Objectives: To investigate the clinical utility of the Vesical Imaging-Reporting and Data System (VI-RADS) by comparing its diagnostic performance for muscle-invasive bladder cancer (MIBC) between radiologists and urologists based on multiparametric MRI, including three-dimensional (3D) fast spin-echo (FSE) T2-weighted acquisitions.

Methods: This study included 66 treatment-naïve patients (60 men, 6 women; mean age 74.0 years) with pathologically proven bladder cancer who underwent multiparametric MRI, including 3D FSE T2-weighted imaging, before transurethral bladder tumour resection between January 2010 and November 2018.

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Article Synopsis
  • Synovial sarcoma is a rare soft tissue cancer that can metastasize to the pancreas, causing complications like bleeding from tumor rupture, which is extremely uncommon.
  • A 27-year-old woman with a history of left femoral synovial sarcoma developed a pancreatic tumor that ruptured, leading to serious abdominal bleeding after consuming alcohol.
  • The patient underwent emergency surgery to remove the ruptured tumor and had a successful recovery, remaining free of relapse six months post-operation without needing further chemotherapy.
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Background: The Response Evaluation Criteria in Solid Tumors (RECIST) for computed tomography (CT) is preoperatively used to evaluate therapeutic effects. However, it does not reflect the pathological treatment response (PTR) of pancreatic ductal adenocarcinoma (PDAC). The Positron Emission Tomography Response Criteria in Solid Tumors (PERCIST) for positron emission tomography (PET)/CT is effective in other cancers.

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Pancreatic hamartoma is a rare benign tumor. Its preoperative diagnosis is challenging. We present a case of pancreatic hamartoma whose radiological-pathological correlation was evaluated in detail.

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