Hepatocellular carcinoma: assessment of resectability by computed tomography and ultrasound

A retrospective review of the CT and ultrasound scans from examinations of 30 patients who had hepatocellular carcinoma (hepatoma) was undertaken with special emphasis placed on evaluation of hepatic distribution of tumor, vascular invasion, and extrahepatic spread. Although both CT and ultrasound detected hepatoma in 29 of 30 patients (96%), CT showed more extensive hepatic parenchymal involvement in eight of the patients. Vascular invasion was seen more frequently with ultrasound than with CT. Invasion into the main portal vein was seen by ultrasound in 11 of 30 patients (37%). Extrahepatic spread of tumor was much more frequently detected by CT and was present in 21 of 30 patients (70%). A reasoned approach to the diagnostic workup of hepatomas that will minimize invasive procedures and unnecessary surgery is presented.     

Self-limiting extravasation in the unused urinary bladder

Patients being evaluated as potential renal transplant recipients routinely undergo voiding cystourethrography. Eight patients were encountered in whom extraperitoneal extravasation was noted from the region of the ureterovesical junction during voiding (seven patients) or during filling (one patient). Extravasation was bilateral in six patients and unilateral in two. The patients neither experienced symptoms related to the extravasation, required treatment, nor had sequelae. Five of the eight patients have subsequently received renal transplants and their bladders were observed to be normal at surgery. Cystoscopy was also performed in two of these five patients and was unremarkable. After transplantation, these patients' bladders functioned normally and gave rise to no symptoms.     

A distribution system for digital images from diverse image sources

This paper proposes a unified image-processing and viewing system as a viewing station and initially as the central file server in a unified digital image distribution and processing network, linking various digital image sources through a high speed data link and a common image format. The network allows for viewing and processing of all images produced within the complex and for locating viewing stations in any number of convenient areas. The system proposed can be slowly expanded to include all the digital images produced within the department or institution.     

Epidemiologic background and long-term course of disease in human immunodeficiency virus type 1-infected blood donors identified before routine laboratory screening. Transfusion Safety Study Group

BACKGROUND: The long-term course of human immunodeficiency virus type 1 (HIV-1)-related disease among seropositive blood donors has not been described. The enrollment and epidemiologic background of HIV-1- infected donors in the Transfusion Safety Study and their immunologic and clinical progression are described. STUDY DESIGN AND METHODS: Through the testing of approximately 200,000 sera from donations made in late 1984 and early 1985, 146 anti-HIV-1-positive donors and 151 uninfected matched donors were enrolled. These two cohorts were followed with 6-month interval histories and laboratory testing. RESULTS: Seropositive donors detected before the institution of routine anti-HIV-1 screening disproportionately were first-time donors and men with exclusively male sexual contacts. The actuarial probability of a person's developing AIDS within 7 years after donation was 40 percent; the probability of a person's dying of AIDS was 28 percent. AIDS developed more often when the donor was p24 antigen-positive at donation. Over a 3-year period, significant decreases occurred in CD4+, CD2+CD26+, CD4+CD29+, and CD20+CD21+ counts, but not in CD8+ subsets, CD20+, or CD14+. CONCLUSION: The high proportions of first-time donations and exclusively homosexual men among seropositive donors suggest that test-seeking may have contributed to the high HIV-1 prevalence in the repository. Implementation of alternative test sites when routine donor screening began in 1985 may have averted many high- risk donations. The disease course in HIV-1-infected donors had the same wide spectrum of immunologic and clinical manifestations as were reported for other cohorts.     

What do we know about how to do audit and feedback? Pitfalls in applying evidence from a systematic review

Background  

Improving the quality of health care requires a range of evidence-based activities. Audit and feedback is commonly used as a quality improvement tool in the UK National Health Service [NHS]. We set out to assess whether current guidance and systematic review evidence can sufficiently inform practical decisions about how to use audit and feedback to improve quality of care.     

Validation of a 3D CT method for measurement of linear wear of acetabular cups

Background

We evaluated the accuracy and repeatability of a 3D method for polyethylene acetabular cup wear measurements using computed tomography (CT). We propose that the method be used for clinical in vivo assessment of wear in acetabular cups.

Material and methods

Ultra-high molecular weight polyethylene cups with a titanium mesh molded on the outside were subjected to wear using a hip simulator. Before and after wear, they were (1) imaged with a CT scanner using a phantom model device, (2) measured using a coordinate measurement machine (CMM), and (3) weighed. CMM was used as the reference method for measurement of femoral head penetration into the cup and for comparison with CT, and gravimetric measurements were used as a reference for both CT and CMM. Femoral head penetration and wear vector angle were studied. The head diameters were also measured with both CMM and CT. The repeatability of the method proposed was evaluated with two repeated measurements using different positions of the phantom in the CT scanner.

Results

The accuracy of the 3D CT method for evaluation of linear wear was 0.51 mm and the repeatability was 0.39 mm. Repeatability for wear vector angle was 17°.

Interpretation

This study of metal-meshed hip-simulated acetabular cups shows that CT has the capacity for reliable measurement of linear wear of acetabular cups at a clinically relevant level of accuracy.Debris due to polyethylene wear may trigger aseptic loosening in total hip arthroplasty (THA) (Santavirta et al. 1995, Mohanty 1996). With the methods currently available, it is difficult to determine small amounts of wear in vivo without using invasive methods such as radiostereometric analysis (RSA) (Schewelov et al. 2004). Conventional radiography is the most common routine clinical method, but it yields only 2D results with low accuracy—of about 4 mm (Clarke et al. 1976). Several 3D reconstruction methods exist, such as AP radiographs, but these methods are still too complicated to be reliable in a routine clinical setting and the accuracy tends to be lower in a clinical situation than under laboratory conditions (Clarke et al. 1976).Current multislice CT scanners, which offer accurate spatial volume resolution in both 2D and 3D without substantial distortion, are non-invasive and fast. Metal artifacts from the implant are suitably suppressed by software algorithms from the CT manufacturers. We have previously shown that CT can also be used for evaluation of acetabular cup position and migration (Olivecrona et al. 2002, 2003c, 2004). A retrieval study showed that CT can also be used for evaluation of 3D penetration of the femoral head into metal-backed acetabular cups with an accuracy of 1 mm (Olivecrona et al. 2005). Based on that study, we developed a new approach for wear assessment using CT and it was shown to achieve an accuracy of 0.6 mm and a repeatability of 0.4 mm (Olivecrona et al. 2005). This new approach relies on placing several landmarks in the 3D CT volume on the surfaces of the head and cup. Spheres are then fitted to these data points, and from these spheres the femoral head penetration can be calculated.As part of this study, the method described was developed futher—mainly with improved software that allowed many more landmark points to be placed on the 3D surfaces, and the possibility of comparing the same implant at 2 time points (e.g. pre-wear and post-wear). A model study was performed with a hip simulator in order to estimate the accuracy and reproducibility of the method proposed. Both gravimetric results and measurement results from a coordinate measurement machine (CMM) were used as reference methods. We used a different cup design with a metal mesh molded into the polyethylene outer surface, in order to avoid back-side wear.Due to an unanticipated upgrade of the CT software, we also simulated the clinical situation where a CT scan is done postoperatively and then at a follow-up several years later, by using a different CT scan protocol before and after wear.