Publications by authors named "Akihiro Kakimoto"

Peripheral nerve tension is known to be related to the pathophysiology of neuropathy; however, assessing this tension is difficult in a clinical setting. In this study, we aimed to develop a deep learning algorithm for the automatic assessment of tibial nerve tension using B-mode ultrasound imaging. To develop the algorithm, we used 204 ultrasound images of the tibial nerve in three positions: the maximum dorsiflexion position and -10° and -20° plantar flexion from maximum dorsiflexion.

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The effects of lead equivalent and lens area of radiation-protective eyewear on lens exposure control were examined. The simulated patient underwent 10-min X-ray fluoroscopy, and the lens dose of the simulated surgeon wearing radiation protection glasses was measured using lens dosemeters attached to the corner of the eye and eyeball. In total, 10 types of radiation protection glasses were selected for measurement.

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Although convolutional neural networks (CNNs) demonstrate the superior performance in denoising positron emission tomography (PET) images, a supervised training of the CNN requires a pair of large, high-quality PET image datasets. As an unsupervised learning method, a deep image prior (DIP) has recently been proposed; it can perform denoising with only the target image. In this study, we propose an innovative procedure for the DIP approach with a four-dimensional (4D) branch CNN architecture in end-to-end training to denoise dynamic PET images.

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To minimize motion-related distortion of reconstructed images, conventional positron emission tomography (PET) measurements of the brain inevitably require a firm and tight head restraint. While such a restraint is now a routine procedure in brain imaging, the physiological and psychological consequences resulting from the restraint have not been elucidated. To address this problem, we developed a restraint-free brain PET system and conducted PET scans under both restrained and non-restrained conditions.

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Background: Amyloid imaging with positron emission tomography (PET) often comes with glucose metabolic imaging in diagnosis of Alzheimer's disease (AD).

Objective: The present purpose was to explore the clinical valence of early amyloid-β (Aβ) PET scans to determine whether they could substitute for other imaging biomarkers (early and delayed Aβ images of 11C-Pittsburgh compound B (PIB) and 18F-fluorodeoxyglucose (FDG) images) in the AD spectrum.

Methods: Thirty healthy control subjects, 20 patients with mild cognitive impairment, and 45 patients with AD underwent 11C-PIB and 18F- FDG PET.

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The psoas-major muscle has been reported as a predictive factor of sarcopenia. The cross-sectional area (CSA) of the psoas-major muscle in axial images has been indicated to correlate well with the whole-body skeletal muscle mass. In this study, we evaluated the segmentation accuracy of low-dose X-ray computed tomography (CT) images of the psoas-major muscle using the U-Net convolutional neural network, which is a deep-learning technique.

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Background: The α7 subtype of the nicotinic acetylcholine receptor (nAChR) is considered important in higher cognitive functions, and cholinergic loss underpins the pathophysiology of Alzheimer's disease (AD). However, the relationships between α7 nAChR function and clinical functions or amyloid-β (Aβ) deposition remain to be explored in the living AD brain.

Objective: We aimed to elucidate the relationship between α7 nAChR availability in the specific cholinergic region and cognitive decline in the Aβ-confirmed AD brain.

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Unlabelled: With a large database, we aimed to evaluate sex-specific distinctive changes in brain glucose metabolism and morphology during normal aging using MRI and (18)F-FDG PET.

Methods: A total of 963 cognitively healthy adults were included in this study. All subjects completed a medical questionnaire, took the mini-mental state examination, and underwent brain MRI and whole-body (18)F-FDG PET.

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Idiopathic hypoparathyroidism (IHP) is accompanied by cognitive impairment. We report the case of a 70-year-old IHP patient with cognitive disturbance. Brain computed tomography showed bilateral calcification in basal ganglia, thalamus, and cerebellum.

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Purpose: We devised a new computer-aided diagnosis method to segregate dementia using one estimated index (Total Z score) derived from the Brodmann area (BA) sensitivity map on the stereotaxic brain atlas. The purpose of this study is to investigate its accuracy to differentiate patients with Alzheimer's disease (AD) or mild cognitive impairment (MCI) from normal adults (NL).

Methods: We studied 101 adults (NL: 40, AD: 37, MCI: 24) who underwent (18)FDG positron emission tomography (PET) measurement.

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Although there is a great deal in the literature about the clinical accuracy of computed tomography (CT)-based navigation systems for acetabular cup orientation and leg length discrepancy in total hip arthroplasty, there is little analysis of femoral stem orientation. Thirty total hip arthroplasties in which CT-based navigation system had been used had their anteversion, valgus angle of stem, and leg length discrepancy measured on postoperative CT data. Differences in postoperative measurements from intraoperative records were -0.

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Purpose: The purpose of this study was to compare non-fiducial based surface registration technique (DigiMatch) with the conventional locator pin-based registration technique in performing cementless total hip arthroplasty (THA) using ROBODOC system.

Methods: Eighty-one THA were performed using pin-based technique and forty-three were performed using the DigiMatch technique. The average follow-up term was 38 months.

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Background: The benefits of robotic techniques for implanting femoral components during THA are still controversial.

Questions/purposes: The purpose of this study was to prospectively compare the results and complications of robotic-assisted and hand-rasping stem implantation techniques.

Method: The minimum followup was 5 years (mean, 67 months; range, 60-85 months).

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Objective: The purpose of this study was to propose our CT-based planning approach for knee arthroplasty on the basis of the femoral flexion-extension (FE) axis, and to evaluate whether this approach was valid by comparing the results with those obtained using conventional anterior-referenced planning.

Materials And Methods: Virtual implantation of a sagittal single-radius component was performed in 34 normal knees. The transepicondylar axis (TEA) was identified as the FE axis, and was modified in the coronal plane to intersect the femoral mechanical axis at a right angle, if necessary.

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The ROBODOC system has provided better fit and fill of the stem and less destruction of the bony architecture than with manual surgery. These benefits might affect femoral periprosthetic bone remodeling. We evaluated the effects of robotic milling in cementless total hip arthroplasty (THA) in a longitudinal 24-month follow-up study using dual energy X-ray absorptiometry (DEXA) and plain radiographs of 29 patients (31 hips) after ROBODOC THA and 24 patients (27 hips) after manual THA with the same stem design.

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In 17 patients with unilateral hip disease who underwent total hip arthroplasty (THA), the gait was analyzed preoperatively and 1, 3, 6, and 12 months after unilateral THA using a Vicon system to assess the recovery of walking speed and symmetrical movement of the hip, knee, ankle, and pelvis. The walking speed of these patients reached that of normal Japanese persons by 12 months after surgery. Walking speed was correlated with the range of hip motion on the operated side at 1 month postoperatively, and was correlated with the hip joint extension moment of force on both sides from 3 to 6 months after surgery.

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