Evaluation of three-dimensional iterative image reconstruction in virtual monochromatic imaging at 40 kilo-electron volts: phantom and clinical studies to assess the image noise and image quality in comparison with other reconstruction techniques.

OBJECTIVE: The purpose of this study was to evaluate the image quality in virtual monochromatic imaging (VMI) at 40 kilo-electron volts (keV) with three-dimensional iterative image reconstruction (3D-IIR). METHODS: A phantom study and clinical study (31 patients) were performed with dual-energy CT (DECT). VMI at 40 keV was obtained and the images were reconstructed using filtered back projection (FBP), 50% adaptive statistical iterative reconstruction (ASiR), and 3D-IIR. We conducted subjective and objective evaluations of the image quality with each reconstruction technique. RESULTS: The image contrast-to-noise ratio and image noise in both the clinical and phantom studies were significantly better with 3D-IIR than with 50% ASiR, and with 50% ASiR than with FBP (all, p < 0.05). The standard deviation and noise power spectra of the reconstructed images decreased in the order of 3D-IIR to 50% ASiR to FBP, while the modulation transfer function was maintained across the three reconstruction techniques. In most subjective evaluations in the clinical study, the image quality was significantly better with 3D-IIR than with 50% ASiR, and with 50% ASiR than with FBP (all, p < 0.001). Regarding the diagnostic acceptability, all images using 3D-IIR were evaluated as being fully or probably acceptable. CONCLUSIONS: The quality of VMI at 40 keV is improved by 3D-IIR, which allows the image noise to be reduced and structural details to be maintained. ADVANCES IN KNOWLEDGE: The improvement of the image quality of VMI at 40 keV by 3D-IIR may increase the subjective acceptance in the clinical setting.

New Fast kVp Switching Dual-Energy CT: Reduced Severity of Beam Hardening Artifacts and Improved Image Quality in Reduced-Iodine Virtual Monochromatic Imaging.

RATIONALE AND OBJECTIVES: To compare degradation of the image quality due to beam hardening artifacts in reduced-iodine-dose virtual monochromatic imaging (VMI) between a new fast kVp switching dual-energy computed tomography (CT) scanner (Revolution CT) and the conventional dual-energy scanner (Discovery CT). MATERIALS AND METHODS: First, a phantom study was performed to quantitatively evaluate beam hardening artifacts in images obtained by VMI reconstruction at different energy levels. In the second study, we performed a retrospective evaluation of the images of 28 patients who had undergone reduced-iodine (300 mg/kg) dual-energy scanning in both Revolution CT and Discovery CT. We evaluated each image quantitatively by measuring the contrast-to-noise ratio (CNR) and qualitatively by scoring the artifacts and image quality. We also calculated the modulation transfer function (MTF) and noise power spectrum (NPS) of the two scanners. RESULTS: In the phantom study, VMI reconstruction of the CT images at 40-70 keV was associated with a significantly greater reduction in the severity of the artifacts in the Revolution CT images as compared to the Discovery CT images. In the retrospective study, there were no significant differences in the CT value of the aorta, noise, or CNR between the two scanners, but the scores for image quality were significantly higher in the Revolution CT images as compared to the Discovery CT images. The MTF of Revolution CT was higher than that of Discovery CT, reflecting the better spatial resolution. CONCLUSION: In Revolution CT, beam hardening artifacts were reduced in reduced-iodine VMI at lower energy levels compared to Discovery CT, contributing to better image quality.

The Use of Service Dogs for People With Physical Disabilities in Japan in Accordance With the Act on Assistance Dogs for Physically Disabled Persons.

Japan learnt how to promote assistance dogs effectively by deliberating the issues and challenges that surrounded assistance dogs in the USA and Europe and the Act on Assistance Dogs for Physically Disabled Persons was issued in 2002. The aim of this paper is to provide information that may be useful for countries and areas that are seeking ways to regulate assistance dogs, especially in the context of the global problem in which dogs are falsely claimed to assist their partners. First, there is a description of the process through which Japan, where pet dogs have not been accepted in society, established the Act, which overcame the shortcomings of the previous situation. Second, it is shown the ways in which people living with assistance dogs have gained the right to have their dogs accompany them in public. Third, the current challenges faced by people with assistance dogs are documented. Finally, pictures of an example of an assistance dog certificate and of an assistance dog sign reveal how far the regulation of assistance dogs is achieved in Japan.

Evaluation of three-dimensional iterative image reconstruction in C-arm-based interventional cone-beam CT: A phantom study in comparison with customary reconstruction technique.

We compared images obtained using a three-dimensional iterative image reconstruction (3D-IIR) algorithm for C-arm-based interventional cone-beam computed tomography (CBCT) with that using the customary reconstruction technique to quantify the effect of reconstruction techniques on image quality.We scanned 2 phantoms using an angiography unit with digital flat-panel system-an elliptical cylinder acrylic phantom to evaluate spatial resolution and a Catphan phantom to evaluate CT number linearity, image noise, and low-contrast resolution. Three-dimensional imaging was calculated using Feldkamp algorithms, and additional image sets were reconstructed using 3D-IIR at 5 settings (Sharp, Default, Soft+, Soft++, Soft+++). We evaluated quality of images obtained using the 6 reconstruction techniques and analyzed variance to test values of the 10% value of each MTF, mean CT number, and contrast-to-noise ratio (CNR), with P < .05 considered statistically significant.Modulation transfer function curves and CT number linearity among images obtained using the customary technique and the 5 3D-IIR techniques showed excellent agreement. Noise power spectrum curves demonstrated uniform noise reduction across the spatial frequency in the iterative reconstruction, and CNR obtained using all but the Sharp 3D-IIR technique was significantly better than that using the customary reconstruction technique (Sharp, P = .1957; Default, P = .0042; others, P < .0001). Use of 3D-IIR, especially the Soft++ and Soft+++ settings, improved visualization of low-contrast targets.Use of a 3D-IIR can significantly improve image noise and low-contrast resolution while maintaining spatial resolution in C-arm-based interventional CBCT, yielding higher quality images that may increase safety and efficacy in interventional radiology.

Changes in the Health Condition after Using a Service Dog of a Person with Complete C5 Spinal Cord Injury: A Qualitative Single Case Study.

BACKGROUND: We report the changes in the health condition after using a service dog of a person with a complete C5 spinal cord injury (SCI). CASE: A 48-year-old married man began using a service dog after suffering a complete C5 SCI. We conducted a semi-structured interview based on the International Classification of Functioning, Disability, and Health (ICF) rehabilitation sets to describe the change in the participant's experience after using a service dog. The interview was converted into written form, and information regarding the changes in the participant's health condition was extracted. These data were categorized by similarity and then classified by the ICF conceptual framework. DISCUSSION: The participant experienced multiple changes in his health condition after using a service dog. These included the following factors from the ICF - "Body Function" category: "increased vitality and motivation," "emergence of self-affirmation," and "physical improvement." Health changes form the "Activities and Participation" category included: "emergence of new roles," "increased resilience," "expansion of moving area," "acquisition of activities incorporated with a service dog assist," "emergence of autonomous health management," "expansion of relation with other people," and "expansion of social activity." The participant experienced "reduction of psychological barriers," categorized under "Personal Factor," and "expansion of support environment," categorized under "Environmental Factor."

Massive splenic infarction and splenic venous thrombosis observed in a patient with acute splenic syndrome of sickle cell traits on contrast-enhanced thin-slice computed tomography.

We report a case of splenic infarction in a patient with sickle cell traits (SCT), focusing on the computed tomography (CT) findings. The patient was an African-American man in his twenties with no past medical history who experienced sudden left upper quadrant pain while climbing a mountain (over 3000 m above sea level). Dynamic contrast-enhanced CT revealed massive non-segmental splenic infarction accompanied with nodule-like preserved splenic tissue. The region of splenic infarction did not coincide with the arterial vascular territory and differed from the features of infarction caused by large arterial embolism. In addition, thrombotic occlusion of the distal splenic vein was depicted on plain and contrast-enhanced thin-slice CT images. Early-phase contrast-enhanced images also showed inhomogeneous enhancement of the hepatic parenchyma. The patient's symptoms improved with conservative therapy. A hemoglobin electrophoresis test confirmed the diagnosis of SCT. SCT is usually asymptomatic, but hypoxic environments may induce acute splenic syndrome, which is commonly manifested as splenic infarction. We observed splenic venous thrombosis and inhomogeneous hepatic parenchymal enhancement in addition to a huge splenic infarction in our patient. To the best of our knowledge, this is the first report describing the specific imaging findings, particularly splenic venous thrombosis and inhomogeneous hepatic parenchymal enhancement, of acute splenic syndrome in a patient with previously undiagnosed SCT. These findings demonstrate the pathophysiology of SCT, and may help with the diagnosis of this disease.

The effect of service dogs on the improvement of health-related quality of life.

To assess the effects of service dogs on health-related quality of life (HRQOL), we conducted a survey of 10 service dog owners using SF-36v2 (Medical Outcomes Study 36 Item Short-Form Health Survey Version 2.0) and compared it with a matched control group of people with physical disabilities who did not have service dogs but were eligible for one. The scores for mental health and role emotional of service dog owners were relatively high, and their mental component summary was higher than the general population norm. These results indicate that service dogs affect the mentality of their owners. The comparison with the control group indicated that service dogs alleviate the mental burden of daily activities, and subjectively improved the physical functioning of their owners. This study showed that service dogs have positive functional and mental effects on their disabled owners.