PubMed · 7455238
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B Cappelli. 1980. [The duodenum].. https://pubmed.ncbi.nlm.nih.gov/7455238/
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Radiological synopsis of primary gastrointestinal lymphoma depends on the growth direction and dynamism of the tumor, i.e. grade of malignancy and stage of the pathological processes at diagnosis. Initial nodal-polypoid lesions, because of their mucosal/submucosal aggregation, in combination with more or less pathological small bowel relief, are successfully diagnosed by conventional barium studies. Progressive ulcerous and narrowing destruction of the gut wall, as a result of the advanced mural infiltration, increases the success rate of tomographic examination. Tomographic imaging, particularly computed tomography, is considered the primary method, alongside the selective small bowel double-contrast study for demonstration of diffuse tumor infiltration.
BACKGROUND: The extent to which national guidelines affect actual clinical practice is largely unknown. OBJECTIVE: To gauge the impact of a national guideline about dyspepsia on subsequent clinical practice. DESIGN: We compared trends in the rates of the two principal diagnostic tests used to evaluate dyspepsia: upper gastrointestinal tract series (UGI) and endoscopy. METHODS: We used the Health Care Financing Administration's (Baltimore, Md) 100% National Medicare part B file to determine annual counts for the two procedures in each of 10 years (1984 through 1993). To calculate procedure rates, we divided the number of procedures in each year by the total population enrolled in Medicare part B in that year. RESULTS: In 1984, before publication of the guideline, the UGI rate was more than triple the rate of endoscopy (UGI rate, 59 per 1000 beneficiaries; endoscopy rate, 17 per 1000). Subsequent to publication of the guideline in 1985, UGI use slowly decreased while endoscopy utilization slowly increased. The rate of change for both procedures was steady over the 10-year period. Endoscopy rates finally exceeded UGI in 1993 (endoscopy, 37 per 1000; UGI, 36 per 1000). CONCLUSIONS: Despite a prominent national guideline, UGI utilization remains high and is slowly decreasing. Because utilization data before 1984 are incomplete, we cannot isolate the precise impact of the guideline. However, the slow decline in UGI utilization suggests that, at best, the guideline had limited impact on clinical practice. If this response is representative of other guidelines, alternative approaches to change clinical practice will need to be found.
To determine the effect of BaSO4 on the fatigue crack growth rate, da/dN = C(delta K)n, of poly(methyl methacrylate) (PMMA) bone cement, radiopaque bone cement, radiolucent bone cement, and commercial PMMA (Plexiglas) were tested using a methodology based on ASTM E647. The crack growth rate of radiopaque bone cement was one order of magnitude less than that of radiolucent. Fractographic analysis showed that the regions of rapid catastrophic fracture were smooth for all materials tested. The radiopaque fatigue surface was rough and characterized by ragged-edged stacked plateaus, a morphology consistent with the model of crack propagation through the interbead matrix. Voids were visible in the interbead matrix on the order of the size of BaSO4 particles. The fatigue surface of radiolucent bone cement was relatively smooth, a morphology consistent with crack propagation through both the PMMA beads and interbead matrix. Fatigue striations were visible, and their spacing correlated well with crack propagation rates. The striations indicated an increased crack growth rate through the PMMA beads.