Composite x-ray image assembly for large-field digital mammography with one- and two-dimensional positioning of a focal plane array.

To demonstrate the feasibility of a novel large-field digital mammography technique, a 1024 x 1024 pixel Loral charge-coupled device (CCD) focal plane array (FPA) was positioned in a mammographic field with one- and two-dimensional scan sequences to obtain 950 x 1800 pixel and 3600 x 3600 pixel composite images, respectively. These experiments verify that precise positioning of FPAs produced seamless composites and that the CCD mosaic concept has potential for high-resolution, large-field imaging. The proposed CCD mosaic concept resembles a checkerboard pattern with spacing left between the CCDs for the driver and readout electronics. To obtain a complete x-ray image, the mosaic must be repositioned four times, with an x-ray exposure at each position. To reduce the patient dose, a lead shield with appropriately patterned holes is placed between the x-ray source and the patient. The high-precision motorized translation stages and the fiber-coupled-scintillating-screen-CCD sensor assembly were placed in the position usually occupied by the film cassette. Because of the high mechanical precision, seamless composites were constructed from the subimages. This paper discusses the positioning, image alignment procedure, and composite image results. The paper only addresses the formation of a seamless composite image from subimages and will not consider the effects of the lead shield, multiple CCDs, or the speed of motion.

CCD mosaic technique for large-field digital mammography.

The authors present a novel technique for large-field digital mammography. The instrument uses a mosaic of electronic digital imaging [charge coupled device (CCD)] arrays, novel area scanning, and a radiation exposure and scatter reducing mechanism. The imaging arrays are mounted on a carrier platform in a checker-board pattern mosaic. To fill in the gaps between array-active areas the platform Is repositioned three times and four X-ray exposures are made. The multiple image areas are then recombined by a digital computer to produce a composite image of the entire region. To reduce X-ray scatter and exposure, a lead aperture plate is interposed between X-ray source and patient. The aperture plate has a mosaic of square holes in alignment with the imaging array pattern and the plate is repositioned in synchronism with the carrier platform. The authors discuss proof-of-concept testing demonstrating technical feasibility of their approach. The instrument should be suitable for incorporation into standard mammography units. Unique features of the new technique are: large field coverage (18x24 cm); high spatial resolution (14-17 lp/mm); scatter rejection; and excellent contrast characteristics and lesion detectability under clinical conditions.

[Appearance of antibodies against hepatitis type A virus (HAV) in alcoholics]. / Wystepowanie przeciwcial przeciwko wirusowi zapalenia watroby typu A (HAV) u alkoholików.

In 144 alcoholics--patients of alcoholic outpatient clinic anti-HAV antibodies were studied using the commercially available ELISA test. Anti-HCV antibodies were found in 86% of the alcoholics, and this prevalence was not higher than in the control group. No differences were found in the titre of antibodies against cytomegaly and herpes virus between the subjects with and without anti-HAV antibodies which suggests the specificity f the determined anti-HAV antibodies.

Prevalence of markers of hepatotropic viruses among drug addicts in Warsaw, Poland.

We studied 100 unselected parenteral drug abusers for infection with hepatitis C, B, A and D virus (HCV, HBV, HAV and HDV). Seventy-six percent had serological evidence of HCV infection. 12% were positive for HBsAg and at least one marker of HBV infection was present in 69%. These results were significantly higher than in a matched control population. Compared to controls, the prevalence of anti-HAV (65%) was not significantly increased in drug addicts. Of the anti-HCV-positive drug addicts, 80.3% had at least one marker of HBV infection compared to 33.3% of anti-HCV-negative cases (p less than 0.001). No such correlation was found between the prevalence of HCV or HBV infection markers and the presence of anti-HAV. Antibodies against HDV were detected in 16 (16%) of the samples from drug addicts. No significant association was found between antibodies to HCV and gender, age and duration of drug abuse. The risk of HBV infection increased significantly with years of drug abuse but was not associated with age and sex. The presence of anti-HAV was related to age only. Sixteen (16%) of the subjects were definitely positive for anti-HIV-1, but at the time of the study they were asymptomatic. No significant association was found between the presence of anti-HIV and the prevalence of serological markers of HBV, HCV, HAV and HDV infection.

[Occurrence of antibodies against hepatitis C virus (HCV) among alcoholics]. / Wystepowanie przeciwcial przeciwko wirusowi zapalenia watroby typu C (HCV) u alkoholików.

144 consecutive alcoholics attending an outpatient clinic were tested for the prevalence of anti-HCV with commercially available ELISA test (Abbott HCV EIA). Positive sera were further tested with neutralization assay (Abbott HCV Neutralization Assay). Anti-HCV were found in 35 (24%). There was no difference in the prevalence or mean titre of anti-CMV and anti-HSV between patients with and without anti-HCV what points to the specificity of tested antibodies.

Introduction of hepatitis delta virus into Polish drug community.

The prevalence of hepatitis delta virus (HDV) infection was studied in 140 unselected intravenous drug addicts whose sera were drawn between 1985 and 1986 and in 100 addicts from whom sera were obtained between 1988 and 1989. It was observed that 1.8% of those positive for hepatitis B virus (HBV) markers from the earlier period and 23.2% of those from the later period had detectable anti-delta antibodies. Among drug addicts referred with acute or chronic HBV infection, the first evidence of HDV infection was found in 1986. We conclude that HDV infection was introduced into the Warsaw drug community in the mid 1980s.

[Delta virus infection among drug addicts]. / Zakazenie wirusem zapalenia watroby typu delta wsród narkomanów.

Altogether 240 unselected intravenous drug addicts were tested for the presence of infection with delta virus (HDV). Anti-delta were found in 16 (16%) out of 100 drug addicts tested in the years 1988-1989 and in only one drug addict (0.7%) out of 140 tested in the years 1985-1986. It seems that delta virus has been introduced to Warsaw drug community in the mid-eighties and has spread enormously since that time.

[Non-A, non-B hepatitis--epidemiologic and clinical aspects]. / Wirusowe zapalenie watroby typu nie-A, nie-B--aspekty epidemiologiczne i kliniczne.

In the years 1986-90 530 consecutive patients with acute hepatitis were hospitalized in the Department of Hepatology of the Institute of Infectious and Parasitic Diseases in Warsaw. Hepatitis A was diagnosed in 34 cases (6.4%), hepatitis B in 436 (82.3%), CMV infection in 5 (0.9%) and 55 cases (10.4%) were classified as hepatitis non-A, non-B. In 47 cases (85%) of non-A, non-B hepatitis in 8 (15%) the source of infection was unclear. In 50% of patients with parenteral exposure transaminases remained elevated for longer than 6 months, while all patients with no known exposure recovered.

Hepatitis C virus antibody in Poland.

To assess the epidemiology of hepatitis C virus (HCV) in Poland, anti-HCV was studied in patients with acute and chronic non-A, non-B (NANB) hepatitis, in healthy adults, and in subjects at risk. Anti-HCV prevalence was 2% in 152 blood donors, 78% in 95 parenteral drug addicts, 21% in 112 alcoholics, and 86% in 42 patients with chronic NANB hepatitis. Among 34 prospectively followed patients with acute NANB hepatitis 17 (50%) developed anti-HCV. It seems that HCV infection is responsible for the majority of NANB hepatitis in Poland and is common in parenteral drug abusers and alcoholics.

[Antibodies against Cytomegalovirus and Herpes simplex virus in alcoholics and drug addicts]. / Przeciwciala przeciwko wirusowi cytomegalii i wirusowi herpes simplex u alkoholików i narkomanów.

Anti-CMV and anti-HSV type 1 of the IgG class were tested in 123 consecutive outpatient alcoholics and 95 consecutive drug addicts admitted to a detoxification ward. The prevalence of both viral markers in these groups was not different from the prevalence found among controls, however, antibody titres were significantly higher. Only weak correlation was found between titres of anti-CMV and anti-HSV in tested subjects. The reasons responsible for high titres of anti-CMV and anti-HSV remain to be determined.

[Cytomegalovirus hepatitis]. / Zapalenie watroby wywoøane zakazeniem wirusem cytomegalii.

Among 530 consecutive patients hospitalized for acute hepatitis cytomegalovirus infection was diagnosed in 5 (0.9%). In 2 cases the infection was due to blood transfusion. The course of the disease was Got essentially different from hepatitis A, B, or non-A, non-B, however, clinical and biochemical manifestations of cholestasis were common. All biochemical abnormalities returned to normal within few weeks. In conclusion, it seems that cytomegalovirus is a rare cause of clinically overt hepatitis and its course is often cholestatic.