[Clinical Validation of Chest X-ray Educational Content for Radiography Students Using Gaze Information].

Purpose: Radiography training for students in colleges of radiology should be based on real clinical situations. The purpose of this study was to verify the clinical validity of our originally developed scenarios for chest X-ray training and the instructional contents using gaze information of experienced radiology technologists (RTs).

Methods: We divided 8 RTs with different experiences into an evaluator group (3 RTs) and a subject group (5 RTs).

Impact of Thickened Liquids on Laryngeal Movement Velocity in Patients with Dysphagia.

Considering that thickened liquids are frequently used for patients with dysphagia, elucidating their impact on laryngeal dynamics is important. Although studies have investigated the impact of thickened liquids on laryngeal movement velocity among healthy young adults, no study has examined the same among patients with dysphagia. We aimed to elucidate the influence of bolus consistency on laryngeal movement velocity and surface electromyographic activity of the suprahyoid muscles in patients with dysphagia.

Validation of Optimum ROI Size for I-FP-CIT SPECT Imaging Using a 3D Mathematical Cylinder Phantom.

Objectives: The partial volume effect (PVE) of single-photon emission computed tomography (SPECT) on corpus striatum imaging is caused by the underestimation of specific binding ratio (SBR). A large ROI (region of interest) set using the Southampton method is independent of PVE for SBR. The present study aimed to determine the optimal ROI size with contrast and SBR for striatum images and validate the Southampton method using a three-dimensional mathematical cylinder (3D-MAC) phantom.

Quantitation of specific binding ratio in I-FP-CIT SPECT: accurate processing strategy for cerebral ventricular enlargement with use of 3D-striatal digital brain phantom.

This study aimed to evaluate the effect of ventricular enlargement on the specific binding ratio (SBR) and to validate the cerebrospinal fluid (CSF)-Mask algorithm for quantitative SBR assessment of I-FP-CIT single-photon emission computed tomography (SPECT) images with the use of a 3D-striatum digital brain (SDB) phantom. Ventricular enlargement was simulated by three-dimensional extensions in a 3D-SDB phantom comprising segments representing the striatum, ventricle, brain parenchyma, and skull bone. The Evans Index (EI) was measured in 3D-SDB phantom images of an enlarged ventricle.

[Evaluation of Accuracy for Quantitative Predictor of Hepatic Functional Reserve Using Planar and SPECT Images in the Tc-GSA Scintigraphy].

Purpose: The purpose of this study was to evaluate the accuracy for quantitative predictor of hepatic functional reserve using planar and single photon emission computed tomography (SPECT) images.

Methods: We acquired planar and SPECT images of the myocardial torso phantom and calculated LHL (uptake ratio of the liver to the liver plus heart). Planar images were used with and without scatter correction.

[Development of Realistic Striatal Digital Brain (SDB) Phantom for I-FP-CIT SPECT and Effect on Ventricle in the Brain for Semi-quantitative Index of Specific Binding Ratio].

Purpose: This study aimed at developing the realistic striatal digital brain (SDB) phantom and to assess specific binding ratio (SBR) for ventricular effect in the I-FP-CIT SPECT imaging.

Methods: SDB phantom was constructed in to four segments (striatum, ventricle, brain parenchyma, and skull bone) using Percentile method and other image processing in the T2-weighted MR images. The reference image was converted into 128×128 matrixes to align MR images with SPECT images.

Quantitative analysis of effects of hemodynamic stress on temporal variations of cardiac phases in models of human carotid bulbs.

In this study, we evaluated the hemodynamics of carotid artery models with carotid bulbs of various sizes using computational fluid dynamics (CFD) and the Fluent CFD software. The oscillatory shear index (OSI) and flow velocity distribution were evaluated in carotid models without a carotid bulb and with carotid bulbs of known geometry (major axis of 10, 11, 12, 13, and 14 mm; carotid bifurcation angle of 50°). Furthermore, the diameters of the common carotid artery, the external carotid artery, and the internal carotid artery were defined as 7.

Effect of resolution recovery using graph plots on regional cerebral blood flow in healthy volunteers.

Purpose: We evaluated the effect of resolution recovery (RR) using graph plots on regional cerebral blood flow (rCBF) in brain perfusion single-photon emission computed tomography (SPECT) images derived from healthy volunteers and patients diagnosed with probable Alzheimer's disease.

Method: We acquired brain perfusion SPECT images with scatter correction (SC), computed tomography-based attenuation correction (CTAC), and RR from a three-dimensional brain phantom and from healthy volunteers. We then compared contrast-to-noise ratio, count density ratios, increase maps, and rCBF using statistical parametric mapping 8.

Corneal Dose Reduction Using a Bismuth-Coated Latex Shield over the Eyes During Brain SPECT/CT.

This study aimed to determine whether a bismuth-coated latex shield (B-shield) could protect the eyes during brain SPECT/CT. A shield containing the heavy metal bismuth (equivalent to a 0.15-mm-thick lead shield) was placed over a cylindric phantom and the eyes of a 3-dimensional brain phantom filled with Tc solution.

[Effect of Scatter Limitation Correction with Misregistration between Computed Tomography and Positron Emission Tomography on Scatter Correction: A Physical Phantom Study].

Purpose: This study aimed to evaluate the advantage of scatter limitation correction with misregistration between μ-map in the computed tomography attenuation correction and positron emission tomography in PET/CT study.

Methods: We used torso phantom including simulated tumor and arms phantom. The CT scan was performed by changing the position of arms phantom after PET scan.

Does applying resolution recovery to normal databases confer an advantage over conventional 3D-stereotactic surface projection techniques?

We evaluated a novel normal database (NDB) generated using single photon emission computed tomography (SPECT) data obtained from healthy brains by using a SPECT/CT system, analyzed using a resolution recovery (RR) technique applied to the three-dimensional stereotactic surface projection (3D-SSP) technique. We used a three-dimensional ordered subset expectation maximization method (3D-OSEM) with applied scatter correction (SC), attenuation correction, and RR to reconstruct the data. We verified the accuracy of the novel NDB's values (Z, extent, and error scores), and compared the novel NDB to the 3D-SSP technique by using simulated misery perfusion-related patient data from a conventional NDB.

[The Advantage of 80-row Non-helical Scan Method for Head Computed Tomography: In Basal Ganglia and Parietal].

Purpose: The purpose of this study was to evaluate the advantage of 80-row non-helical scan methods (NH) for the head computed tomography (CT).

Methods: We calculated the noise power spectrum (NPS), contrast-to-noise ratio (CNR), CT values and standard deviation (SD) at slice position, and coefficient of variation (CV) value in head phantom. This study compared the NH method with the helical scan method (HE).

[Evaluation of Resolution Recovery for Each Collimator in Brain Perfusion Image].

Purpose: This study aimed to verify the resolution recovery for each collimator in the brain perfusion image.

Method: To verify the effect of the resolution recovery for each collimator, we evaluated via the three-dimensional brain phantom (phantom) and the normal brain perfusion single photon emission computed tomography (SPECT) data. These data were reconstructed using the three-dimensional ordered subset expectation maximization method (3D-OSEM) (Evolution for bone) that was performed with scatter correction, attenuation correction, and resolution recovery (RR).

Validation of Computed Tomography-based Attenuation Correction of Deviation between Theoretical and Actual Values in Four Computed Tomography Scanners.

Objectives: In this study, we aimed to validate the accuracy of computed tomography-based attenuation correction (CTAC), using the bilinear scaling method.

Methods: The measured attenuation coefficient (μm) was compared to the theoretical attenuation coefficient (μt), using four different CT scanners and an RMI 467 phantom. The effective energy of CT beam X-rays was calculated, using the aluminum half-value layer method and was used in conjunction with an attenuation coefficient map to convert the CT numbers to μm values for the photon energy of 140 keV.

[Accuracy of Modulation Transfer Function for Target Size and Field of View in a Circular Edge Strategy Using the CT Image Measurement Program].

Purpose: The purpose of this study was to evaluate the effects of target diameter and display-field of view (D-FOV) in modulation transfer function (MTF) by circular edge strategy using the computed tomography (CT) image measurement program "CTmeasure".

Methods: We calculated the MTF (MTF(edge)) using the circular edge strategy applied to cylindrical phantom (200 mmφ) that inserted with cylinders have 10, 20, 30, and 40 mm diameters. The phantom images were reconstructed using filtered back projection method varied with D-FOV (240, 320, 400, and 500 mm).

Evaluation of the impact of carotid artery bifurcation angle on hemodynamics by use of computational fluid dynamics: a simulation and volunteer study.

In this study, we evaluated the hemodynamics of carotid artery bifurcation with various geometries using simulated and volunteer models based on magnetic resonance imaging (MRI). Computational fluid dynamics (CFD) was analyzed by use of OpenFOAM. The velocity distribution, streamline, and wall shear stress (WSS) were evaluated in a simulated model with known bifurcation angles (30°, 40°, 50°, 60°, derived from patients' data) and in three-dimensional (3D) healthy volunteer models.

[Evaluation of Measurement Accuracy and Inter-institutional Comparison for Dose Calibrators].

Purpose: The aim of this study was to validate the reliability of dose calibrators for measuring the radioactivity of several radioisotopes in multi-institution.

Methods: We evaluated the measurement accuracy of dose calibrators using a commercially available source ((67) Ga, (99m) Tc, (123) I, (201) TL). Nine dose calibrators (five models) in seven institutions were performed in this study.

[Accuracy of Resolution Recovery in PSF-based Fully-3D PET Image Reconstruction: Simulation and Phantom Study in Multicenter Trial].

Purpose: Recently, the quality of positron emission tomography (PET) images has rapidly improved using resolution recovery algorithm with point spread function (PSF). The aim of this study was to investigate the accuracy of the resolution recovery algorithm using three different PET systems.

Methods: Three PET scanner models, the GE Discovery 600 M (D600M), SIEMENS Biograph mCT (mCT), and SHIMADZU SET-3000GCT/X (3000GCT) were used in this study.

[Novel Index (Hepatic Receptor: IHR) to Evaluate Hepatic Functional Reserve Using (99m)Tc-GSA Scintigraphy].

Purpose: This study aimed to evaluate the novel index of hepatic receptor (IHR) on the regression analysis derived from time activity curve of the liver for hepatic functional reserve.

Methods: Sixty patients had undergone (99m)Tc-galactosyl serum albumin ((99m)Tc-GSA) scintigraphy in the retrospective clinical study. Time activity curves for liver were obtained by region of interest (ROI) on the whole liver.

Acquisition time optimization of positron emission tomography studies by use of a regression function derived from torso cross-sections and noise-equivalent counts.

In this study, we aimed to optimize the positron emission tomography (PET) acquisition time for individual patients by employing a regression function derived from torso cross-sections by using computed tomography (CT) attenuation corrections and the noise-equivalent counts (NECs). We initially determined the standard image quality or the standard NEC at our institution by visually assessing the images acquired from 61 patients. We measured the NECs of the livers and the torso cross-sections of 165 patients who were evaluated with PET/CT with (18)F-2-fluoro-2-deoxy-D-glucose on the basis of our standard protocol of 120 s/bed position.

[Quantitative Analysis of Wall Shear Stress for Human Carotid Bifurcation at Cardiac Phases by the Use of Phase Contrast Cine Magnetic Resonance Imaging: Computational Fluid Dynamics Study].

Purpose: Detailed strategy for regional hemodynamics is significant for knowledge of plaque development on vascular diseases such as atherosclerosis. The aim of this study was to derive relation between atherosclerosis and hemodynamics at human carotid bifurcation by the use of computational fluid dynamics (CFD), and to provide more accurate hemodynamic information.

Methods: Blood velocity datasets at common carotid artery were obtained by phase-contrast cine magnetic resonance imaging (PC cine MRI).

Quantitative comparison of hemodynamics in simulated and 3D angiography models of cerebral aneurysms by use of computational fluid dynamics.

In this study, we evaluated hemodynamics using simulated models and determined how cerebral aneurysms develop in simulated and patient-specific models based on medical images. Computational fluid dynamics (CFD) was analyzed by use of OpenFOAM software. Flow velocity, stream line, and wall shear stress (WSS) were evaluated in a simulated model aneurysm with known geometry and in a three-dimensional angiographic model.

[Evaluation of optimal threshold of Z score map for statistical brain image analysis].

Purpose: Aim of this study was to investigate optimal threshold of Z score when evaluating statistics image of Alzheimer's disease visually.

Method: We classified 53 clinical patients in control and target group, and evaluated the distribution of Z score calculated with statistical brain image analysis for magnetic resonance and perfusion single photon emission computed tomography (SPECT). The optimal Z score threshold was determined from statistical significance that compared previously mentioned groups.

[Validation of dark band artifact reduction using artifact reduction processing methods with low-dose CT images: phantom study].

Purpose: The purpose of this study was to validate the reduction of dark band (DB) artifact using iterative reconstruction (IR) of abdomen CT.

Methods: Phantoms were arranged with and without small phantom assuming arm position at the body side (Phantom-A, -B). Image reconstruction methods were derived by the following four methods: filtered back projection (FBP), IR [adaptive iterative dose reduction using three-dimensional processing: AIDR-3D (MILD)], organ specific reconstruction (OSR), and Boost-3D (Boost).