Publications by authors named "Shinichi Arao"

Article Synopsis
  • Researchers used machine learning techniques to predict the likelihood of endoleaks following thoracic endovascular aneurysm repair (TEVAR) by analyzing patient data and vessel features from pre-operative CT scans.
  • The study trained an extreme Gradient Boosting (XGBoost) system on data from 145 patients—14 with endoleaks and 131 without—and compared its efficacy to traditional measurement methods.
  • Results showed that machine learning significantly outperformed conventional methods in predicting post-TEVAR endoleaks, achieving a higher correlation with patient and vascular characteristics.
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Article Synopsis
  • This study evaluated the effectiveness of a patient-specific contrast enhancement optimizer simulation software (p-COP) in reducing contrast material (CM) dosage during TAVI-CTA in patients with aortic stenosis.
  • Two groups were compared: one used p-COP with an individualized CM protocol, while the other followed a conventional body weight-tailored protocol, analyzing CM amounts, injection rates, and CT values.
  • Results indicated a significant reduction in CM dose and injection rate in the p-COP group, although both groups achieved similar CT values and visualization scores, suggesting the potential of p-COP to optimize contrast use without compromising imagery quality.
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The aim of this study was to estimate the effect of tube voltage on the scattered dose in a computed tomography (CT) room. To this end, we conducted experiments using anthropomorphic phantoms and a CT scanner at different tube voltages during CT. The scattered dose was measured using an electronic pocket dosemeter at 50-cm intervals from the centre of the gantry.

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Objectives: This study aimed to investigate whether machine learning (ML) is useful for predicting the contrast material (CM) dose required to obtain a clinically optimal contrast enhancement in hepatic dynamic computed tomography (CT).

Methods: We trained and evaluated ensemble ML regressors to predict the CM doses needed for optimal enhancement in hepatic dynamic CT using 236 patients for a training data set and 94 patients for a test data set. After the ML training, we randomly divided using the ML-based (n = 100) and the body weight (BW)-based protocols (n = 100) by the prospective trial.

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We investigated the effect of electrocardiographic (ECG) mA-modulation of ECG-gated scans of computed tomography (CTA) on radiation dose and image noise at high heart rates (HR) above 100 bpm between helical pitches (HP) 0.16 and 0.24.

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To evaluate the effects of various patient characteristics on vessel enhancement on arterio-venous fistula (AVF) computed tomography (CT) angiography (AVF-CT angiography). A total of 127 patients with suspected or confirmed shunt stenosis and internal AVF complications were considered for inclusion in a retrospective cohort study. The tube voltage was 120 kVp, and the tube current was changed from 300 to 770 mA to maintain the image quality (noise index: 14) using automatic tube current modulation.

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To compare the radiation dose and diagnostic ability of the 100-kVp protocol, based on the contrast noise ratio (CNR) index, during coronary artery bypass graft (CABG) vessels with those of the 120-kVp protocol. For the 120-kVp scans (150 patients), the targeted image level was set at 25 Hounsfield units (HU) (CNR120 = iodine contrast/25 HU). For the 100-kVp scans (150 patients), the targeted noise level was set at 30 HU to obtain the same CNR as in the 120-kVp scans (i.

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Background: To investigate optimizing the use of different beam shaping filters (viz. small, medium and large) when using different tube voltages during the newborn chest computed tomography (CT) on a GE Lightspeed VCT scanner.

Methods: We used pediatric anthropomorphic phantoms with a 64 detector-row CT scanner while scanning the chest.

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To investigate the pediatric eye lens entrance surface dose for both axial scan modes without an active collimator and helical scan modes with an active collimator on 64 detector-row computed tomography (CT) scanner. We used three pediatric anthropomorphic phantoms with axial and helical scan modes from the superior orbitomeatal line to the crown of the head. We compared the measured dose values of the real-time skin dosemeter at the surfaces of the lens and the image noise at different scan modes.

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Objectives: The aim of this study was to compare prediction ability between ensemble machine learning (ML) methods and simulation software for aortic contrast enhancement on dynamic hepatic computed tomography.

Methods: We divided 339 human hepatic dynamic computed tomography scans into 2 groups. One group consisted of 279 scans used to create cross-validation data sets, the other group of 60 scans were used as test data sets.

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Article Synopsis
  • - The study aimed to assess if the patient-specific contrast enhancement optimizer simulation software (p-COP) could effectively predict contrast enhancement in whole-body computed tomography angiography (WBCTA) by comparing it to a conventional body weight-based protocol.
  • - Patients were divided into two groups: Group A received lower contrast material dosage and injection rates using p-COP, while Group B followed the standard protocol, showing that Group A had a higher acceptable CT number, although not statistically significant.
  • - Results indicated that the p-COP method allowed for reduced contrast material usage without compromising imaging quality, even in patients with lower cardiac output, suggesting it could be a beneficial alternative to traditional methods.
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It is well known that Interventional Radiology (IVR) is useful. However, the patient dose in IVR is increasing because of the prolongation of fluoroscopic time and the increase in the number of radiographies in recent years. We studied the adequacy of the additional filter for the decrease of the skin surface dose in patients with hepatocellular carcinoma of transcatheter arterial embolization (TAE).

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