Comparisons of the effects of 12-week administration of miglitol and voglibose on the responses of plasma incretins after a mixed meal in Japanese type 2 diabetic patients.

To compare the effects of miglitol [an alpha-glucosidase inhibitor (AGI) absorbed in the intestine] and voglibose (an AGI not absorbed) on plasma glucagon-like peptide-1 (GLP-1) and gastric inhibitory polypeptide (GIP) levels, 26 and 24 Japanese type 2 diabetic patients were randomly assigned to receive miglitol or voglibose, respectively. After 12-week administration of both drugs, during 2-h meal tolerance test, plasma glucose, serum insulin and total GIP were significantly decreased and active GLP-1 was significantly increased. Miglitol group showed a significantly lower total GIP level than voglibose group. Miglitol, but not voglibose, significantly reduced body weight (BW). In all participants, the relative change in BW was positively correlated with that of insulin significantly and of GIP with a weak tendency, but not of GLP-1. In conclusion, both drugs can enhance postprandial GLP-1 responses and reduce GIP responses. The significant BW reduction by miglitol might be attributable to its strong GIP-reducing efficacy.

Diurnal changes in urinary excretion of IgG, transferrin, and ceruloplasmin depend on diurnal changes in systemic blood pressure in normotensive, normoalbuminuric type 2 diabetic patients.

Previous studies of diabetic patients indicate that increased urinary excretion of certain plasma proteins (molecular radii <55 A), such as IgG, transferrin, and ceruloplasmin, precede the development of microalbuminuria. Moreover, increases in these urinary proteins predict future development of microalbuminuria. To clarify whether blood pressure changes influence urinary excretion of these proteins, we examined relationships between diurnal blood pressure changes measured by ambulatory blood pressure monitoring and urinary excretion of IgG, transferrin, ceruloplasmin, alpha2-macroglobulin (88 A) and albumin (36 A) measured separately during the day and night in 20 healthy controls and 26 normotensive, normoalbuminuric diabetic patients. Diurnal change in systolic blood pressure was not correlated to urinary excretion of either albumin or alpha2-macroglobulin in either diabetic patients or controls. However, statistically significant correlations between diurnal changes in systolic blood pressure and those of urinary excretion of IgG, transferrin and ceruloplasmin were found in diabetic patients but not in controls. The present findings suggest that urinary excretion of IgG, transferrin, and ceruloplasmin are more easily affected than albuminuria by systemic blood pressure changes in normoalbuminuric diabetic patients. This is supported by our previous finding that urinary excretion of IgG, transferrin and ceruloplasmin increased while albuminuria did not following enhanced glomerular filtration rate after acute protein loading, which causes increased glomerular capillary pressure due to afferent arterioles dilation, mimicking diabetic intra-renal hemodynamics. Taken together, these findings suggest that urinary excretion of IgG, transferrin, and ceruloplasmin may be more sensitive indicators of glomerular capillary pressure change than albuminuria in normoalbuminuric diabetic patients.

Real-time radiology--new concepts for teleradiology.

We propose two new concepts for teleradiology: 'real-time radiology' and 'seamless operation of a workstation to view images from both local and remote hospitals'. In this paper, we describe an experimental real-time radiology system with a new multimedia diagnostic workstation, which has been established under teleradiology concepts and can be used for cooperative diagnosis by interchanging radiographic images bilaterally in real-time during an audio-visual discussion. The clinical evaluation of real-time radiology using a newly developed diagnostic workstation demonstrated the system to be practical and routinely available to enhance the radiological diagnostic quality of teleradiology.

Development of an integrated radiotherapy network system.

PURPOSE: To introduce the process of developing an integrated radiotherapy network. METHODS AND MATERIALS: We developed a new radiotherapy treatment-planning system in 1987 that we named the Computer Tomography (CT) simulator. CT images were immediately transported to multiimage monitors and to a planning computer, and treatment planning could be performed with the patient lying on the CT couch. The results of planning were used to guide a laser projector, and radiation fields were projected onto the skin of the patient. Since 1991, an integrated radiotherapy network system has been developed, which consists of a picture archiving and communicating system (PACS), a radiotherapy information database, a CT simulator, and a linear accelerator with a multileaf collimator. RESULTS: Clinical experience has been accumulated in more than 1,000 patients. Based on our 7 years of experience, we have modified several components of our original CT simulator and have developed a second generation CT simulator. A standard protocol has been developed for communication between the CT scanner, treatment planning computer, and radiotherapy apparatus using the Ethernet network. As a result, treatment planning data can be transported to the linear accelerator within 1 min after completion of treatment planning. CONCLUSION: This system enables us to make optimal use of CT information and to devise accurate three-dimensional (3D) treatment-planning programs. Our network also allows for the performance of fully computer-controlled dynamic arc conformal therapy.

[Trial of a small image network system in a radiology department of an university hospital].

This paper describes the construction of an image network system in Shinshu University Hospital, and some of its current issues and advantages. Our discussion is based on our experience with a PACS system. SAIPACS, which was installed in 1990 for use in clinical conferencing and pre- and post-graduate education, and with a new CT and MRI network, which was subsequently introduced in 1993. The SAIPACS interconnects eight digital imaging modalities, including CT, MRI, XTV-DR (including digital tomosynthesis), FCR, nuclear medicine (RI), DSA, US, and a film digitizer (FD), with a workstation. Transmission time from the magnetic disk of each imaging modality to the SAIPACS image disk is not rapid enough. Therefore, we need to select images for transfer that are pertinent to our specific purpose, to complete image transmission within a practically acceptable period of time. The new CT/MRI network is composed of two CT units, two MRI systems, an image processing unit and a Universal Gateway. It provides faster image transmission than the SAIPACS system, because there is no need to reform image data to send them in a reversible compressed form. A versatile network system connected to the SAIPACS and CT/MRI network enables digital image data to be processed and edited and images to be transferred back to SAIPACS for clinical or educational use.

Chest imaging with dual-energy subtraction digital tomosynthesis.

Dual-energy subtraction digital tomosynthesis with pulsed X-ray and rapid kV switching was used to examine calcifications in pulmonary lesions. The digital tomosynthesis system used included a conventional fluororadiographic TV unit with linear tomographic capabilities, a high resolution video camera, and an image processing unit. Low-voltage, high-voltage, and soft tissue subtracted or bone subtracted tomograms of any desired layer height were reconstructed from the image data acquired during a single tomographic swing. Calcifications, as well as their characteristics and distribution in pulmonary lesions, were clearly shown. The images also permitted discrimination of calcifications from dense fibrotic lesions. This technique was effective in demonstrating calcifications together with a solitary mass or disseminated nodules.

[Development and clinical application of an expert system for supporting diagnosis of 201Tl stress myocardial SPECT].

A consultation expert system which supports our computer aided reporting system was developed. The system was used for the evaluation of the two dimensional polar (bull's eye) display of 201Tl myocardial SPECT. The system consists of patients management (PM) and consultation expert systems (ES). The former is connected to image processors coupled with scinticameras. The bull's eye display of myocardial SPECT is transferred from image processor to the data base of PM. When inference request is made, the feature extraction program extracts information on localization, extent and severity of focal defects comparing count-rates pixel by pixel with the reference obtained from seven normal controls. The inference engine is activated to determine presence of focal defects utilizing diagnostic rules in the knowledge base. The results are sent back to PM and reported with the probability of assurance. Fifty eight patients with old myocardial infarction (OMI), angina pectoris (AP) and other diseases as well as normal controls were included in the study. The decision for presence or absence of focal defects by ES agreed with that by nuclear physicians (NP) in 301 segments among 330 (91%) in stress images. The presence of redistribution in delayed images agreed in 43 segments among 67 (64%). Image interpretation by ES agreed well with that of NP in patients with OMI (19/20) and AP (9/11). Seven were interpreted as normal by both ES and NP. The system is useful, as it provides NP with complementary and supportive information applicable to decision making and reporting. Further clinical experiences can improve knowledge base for better ES function.

Factor analysis of multigated cardiac blood pool scintigram for the measurement of left ventricular ejection fraction.

Left ventricular ejection fraction (EF) was measured by factor analysis (FA) of multigated cardiac blood pool scintigram in 38 consecutive patients, and compared with that measured by the variable ROI method (EFVROI) with automated left ventricular contour detection. FA was automatically performed without operator intervention with a success rate of 100%. The correlation of EF with EFVROI was significant in the group of 22 patients with normal wall motion (r = 0.65, p less than 0.001), and the entire group of patients (r = 0.70, p less than 0.001), but not significant (p = 0.19) in the group of 16 patients with abnormal wall motion. In conclusion, left ventricular ejection fraction can be estimated by factor analysis of MUGA in patients with normal wall motion.

The optimum Butterworth-Wiener filter for I-123 IMP brain SPECT.

The optimum Butterworth-Wiener filter (BWF) for the preprocessing of N-isopropyl-p-[I-123]-iodoamphetamine (I-123 IMP) SPECT was determined by a simulation experiment. Sixty-four images of the brain phantom containing 14.8 MBq of I-123 IMP were collected with a gamma camera equipped with a slant hole collimator during a 360-degree rotation. The images were processed with 27 BWFs of different shapes, followed by SPECT image reconstruction and visual comparison. The optimum BWF had a cutoff frequency of 0.25/pixel, FWHM of four pixels, and constant of 0.05. The image quality was greatly affected by the cutoff frequency of BWF used for preprocessing.

The unfolded map using 201T1 myocardial SPECT.

The unfolded map is a new method to show the 201T1 distribution of left ventricle using SPECT. In 52 cases these maps were obtained at the stress study and 4 h later. The maximal count profiles of the perimeters for each short axis image were unfolded and were arranged from the apex to base of the left ventricle into a two dimensional map. All patients had chest pain and were suspected of coronary artery disease. The unfolded map had significant correlations between coronary arteriogram and exercise ECG findings. In conclusion, this method reflects the ischemic area of left ventricular myocardium, closer to the real left ventricular myocardium than Bull's eye display and is useful in the diagnosis of coronary heart disease.

Optimal preprocessing Butterworth-Wiener filter for Tl-201 myocardial SPECT.

The optimal frequency characteristic of Butterworth-Wiener filters (BWF) for improving the image quality of 201Tl myocardial SPECT was determined by a phantom experiment. Thirty two projection images of the phantom containing 11.1 MBq of 201Tl with 4 different cold lesions were collected during a 180 degree arc of a gamma camera. A set of the projection images were processed with each of 27 different BWFs, and SPECT images were reconstructed by Shepp-Logan filtered backprojection. The SPECT images were evaluated for their diagnostic ability to visibly detect the cold lesions by four nuclear medicine physicians. The lesion contrasts were used as an adjunctive tool to determine the optimum filter. The optimal combination of the parameters determining BWF characteristics (for the data of about 100 count/pixel at the myocardium) is: 1) cutoff of 0.25/pixel, 2) FWHM of 3 pixels, 3) noise/signal ratio of 0.02. FWHM and noise/signal ratio affected lesion contrast much less than cutoff frequency. Clinical myocardial SPECT images processed with the optimal BWF showed less noise and sharper delineation of the myocardium.

Automated body contour detection in SPECT: effects on quantitative studies.

To perform accurate in vivo quantitation by single photon emission computed tomography, we have developed a new method for detecting body contours for the correction of tissue attenuation. Our method can rapidly derive the best fit contours throughout the body by using the measured axial length of the patient body and Fourier filtering the detected contours which are defined by a unique bit-plane algorithm. We have also evaluated the effects of the body contours on the reconstructed images by using various attenuation correction techniques including a precorrection method (Sorenson, 1974), a postcorrection method (Chang, 1978), a weighted backprojection method, and a radial post correction method (Tanaka, 1983 and 1984). Counts in the specified region-of-interest in phantom images reconstructed by the radial postcorrection, weighted backprojection, and postcorrection methods were more strongly affected by inaccurately detected contours than were counts derived from images reconstructed by the precorrection method.