[Research Study on the Effects of Disinfectants on Medical Images and Medical Equipment in Infection Control Measures].

In this study, we investigated the effects of various disinfectants used to prevent infectious diseases on medical images and medical equipment. First, we investigated the effect of residual disinfectant on medical images in CT, mammography (MMG), and general imaging systems. Acrylic discs with various disinfectants attached were photographed using each imaging device, and visual evaluation and changes in image signal values were evaluated. We also conducted a questionnaire survey of each manufacturer regarding cleaning methods for medical devices. With CT/MMG, residual disinfectant could be visually confirmed on the image. Although this could not be confirmed with the general imaging system, a significant difference was confirmed in the image signal values of the general imaging system through statistical analysis. This is thought to be largely due to the influence of nonlinearity in the short-time imaging range of general imaging equipment. In addition, from the responses to a questionnaire survey of each medical device manufacturer, we were able to understand detailed cleaning methods that are not covered in medical device instruction manuals.

Cardiac output obtained from test bolus injections as a factor in contrast injection rate revision of following coronary CT angiography.

BACKGROUND: Optimal contrast enhancement is crucial for the detection of coronary artery stenoses and atherosclerotic changes in coronary CT angiography (CTA). PURPOSE: To demonstrate the feasibility of using the cardiac output (CO) obtained from the test bolus injection data-set (COtest) as a factor in contrast injection rate revision of the following coronary CTA. MATERIAL AND METHODS: The test bolus injection data-sets of 52 consecutive coronary CTAs were examined. COtest was calculated from the test bolus data-set. Aortic peak enhancement (APE) was measured on the following coronary CTA. We simulated the APE at a fixed contrast injection rate of 4 mL/s (simAPE) in each patient. RESULTS: The ranges of COtest and simAPE were 2.82-7.56 L/min and 194-527 Hounsfield Units, respectively. There was a significant negative correlation (R = -0.802, P < 0.001) between simAPE and COtest. CONCLUSION: COtest can be used for injection rate revision on coronary CTA.

[A study of the transport of three dimensional medical images to remote institutions for telediagnosis].

Using a 3D-imaging-create-function server and network services by IP-VPN, we began to deliver 3D images to the remote institution. An indication trial of the primary image, a rotary trial of a 3D image, and a reproducibility trial were studied in order to examine the practicality of using the system in a real network between Hakodate and Sapporo (communication distance of about 150 km). In these trials, basic data (time and receiving data volume) were measured for every variation of QF (quality factor) or monitor resolution. Analyzing the results of the system using a 3D image delivery server of our hospital with variations in the setting of QF and monitor resolutions, we concluded that this system has practicality in the remote interpretation-of-radiogram work, even if the access point of the region has a line speed of 6 Mbps.

Changes in diffusion-weighted images for visualizing prostate cancer during antiandrogen therapy: preliminary results.

OBJECTIVES: To assess the potential of diffusion-weighted imaging (DWI) for monitoring the response to antiandrogen therapy in prostate cancer. METHODS: After patients had undergone 6 months of antiandrogen therapy, we investigated the time-course changes in findings obtained from DWI compared to the findings obtained from T(2)-weighted (T(2)W) images, transrectal ultrasound (TRUS), and prostate-specific antigen (PSA) kinetics. RESULTS: The time-course changes in T(2)W images, TRUS, and PSA kinetics following antiandrogen therapy in the present study were consistent with previous reports. In all patients, the posttreatment hypointense signals on DWI were attenuated. Identification of tumor location was difficult on the basis of changes in magnetic resonance imaging findings following antiandrogen therapy due to the remarkable reduction of the total prostatic volume. Three patients exhibited residual tumors that were easily visualized, and apparent diffusion coefficient values increased after treatment in these patients. However, in 1 patient with neuroendocrine differentiation during antiandrogen therapy, DWI findings revealed that the hypointense signal in the prostate became progressively more pronounced. However, this case showed a low PSA recurrence without remarkable changes in the T(2)W images. CONCLUSIONS: The preliminary results suggest that DWI is useful to understand clinical significance of PSA kinetics in patients with low PSA recurrence during antiandrogen therapy.