20xx年醫(yī)學(xué)專題—肺栓塞的診治ppt(編輯修改稿)
2024-11-14 18:27 本頁面
【文章內(nèi)容簡(jiǎn)介】 tic and further investigation is required. The majority of cases fall into this category which is characterized by scans with subsegmental defects or defects of any size that match abnormalities on the chest xray or the perfusion scan.,第四十一頁，共七十頁。,A low probability category has been suggested by a number of authors. However, as we can see from the PIOPED data this is not a particularly reliable category. Disagreement among experienced readers is common when perfusion defects are small and limit the utility of this category. This study was originally read as showing a small subsegmental defect. Without the arrow, this study has subsequently been called normal by a number of experienced readers,第四十二頁，共七十頁。,Conclusion,Lung scans are sensitive exams that essentially rule out the diagnosis of pulmonary embolus when they are normal. Patients with high probability lungs can often be treated without further workup. Those patients with nondiagnostic studies require further diagnostic investigation.,第四十三頁，共七十頁。,CT of Pulmonary Embolism,Pulmonary infarcts are more readily identified on CT. Modern CT scanners now have faster acquisition times and are providing a detailed assessment of the lung parenchyma that is not available from the chest radiograph. The typical appearance of a pulmonary infarct on CT includes a pleural based density with convex borders and a linear strand at the apex of the triangle,第四十四頁，共七十頁。,The apex of the triangle is often truncated and not wedge shaped which corresponds to the normal configuration of a secondary lobule in the lung periphery. Low attenuation areas within the infarct represents viable lung. It is important to note, however, that this appearance is not specific for pulmonary infarction. The differential diagnosis for this abnormality includes infarct, hemorrhage, pneumonia, fibrosis, neoplasia and edema,第四十五頁，共七十頁。,Since the clinical presentation of pulmonary embolus is usually nonspecific, the findings on CT are often the first clinical indication that the patient may be suffering from pulmonary embolus. In addition to visualizing the area of infarction we are often able to see the clot itself.,第四十六頁，共七十頁。,CT has been show to be especially useful in the assessment of patients with chronic dyspnea and known pulmonary artery hypertension. These patients are often difficult to diagnose as is exemplified by this patient with known sclerodema and pulmonary artery hypertension whose CT unexpectedly showed a large calcified clot in the r
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