tailieunhanh - Evidence-Based Imaging - part 10

Ở những bệnh nhân bị ung thư đại trực tràng, nghiên cứu hình ảnh được mua lại theo định kỳ để phát hiện sự phát triển của bệnh tái phát và để đánh giá gánh nặng của khối u và phản ứng với điều trị. | 524 . Lucey et al. Goals of Imaging In patients with colorectal cancer imaging studies are acquired periodically in order to detect development of recurrent disease and to assess tumor burden and response to therapy. In the cirrhotic patient the main goal of imaging is detection of developing complications the most important of which is HCC. Many imaging modalities currently available have been used for detecting liver metastases with variable success. Regardless of the technique used the ability to detect a focal space-occupying lesion in the liver depends on the size of the tumor the spatial and contrast resolution of the imaging method the difference in contrast and perfusion between the tumor and background liver parenchyma and the adequacy of the method used for displaying the images after acquired 10 . All these factors affect the performance parameters of the various imaging techniques. A test is useful if sensitivity remains high at an acceptable specificity level. In a meta-analysis that studied the detection rate of liver metastases from gastrointestinal malignancies with multiple modalities Kinkel et al. 3 suggest that in order to be useful in clinical practice the minimum acceptable specificity of imaging methods in this context should be 85 . Lower specificities would lead to excessive and unnecessary interventions such as biopsies excessive complementary imaging tests and follow-up examinations. When assessing cost-effectiveness of the imaging methods other factors need to be considered availability cost risks such as radiation and use of toxic contrast agents and potential benefit of tumor detection . likelihood of achieving long-term remission or cure with appropriate therapy . Overall Cost to Society On an individual level cirrhosis results in impaired quality of life and indirect costs involving decreased productivity and lost days from work. The Centers for Disease Control and Prevention conservatively estimates . expenditures in excess