The role of radiological imaging in the diagnosis of acute appendicitis: ULTRASONOGRAPHY Part 3
In most normal appendices, ultrasonography can demonstrate an echogenic layer (arising from the submucosa) surrounded by a hypoechoic layer (the muscularis propria). In some cases, additional luminal, epithelial, subep-ithelial and serosal structures can be identified and give rise to a ‘target’ appearance. The definition of these layers, especially that of the echogenic submucosal layer, is lost with transmural extension of edema, inflammatory infiltrate and necrosis. The normal appendix resembles the terminal ileum sonographically, except that the former generally lacks peristalsis, has a blind end, is less than 6 mm in diameter, is round instead of oval in cross-section, and does not change in configuration with time.
The key sonographic finding of acute appendicitis is a dilated and noncompressible appendix with a thickened wall. An appendicolith, which can be identified by its acoustic shadow, is found in up to 29% to 36% of cases. The loss of the submucosal echogenic layer, as well as the presence of hyperechoic periappendiceal fat and of a locu-lated pericecal fluid collection, are said to be indicative of perforation. The inflamed appendix is less likely than the normal appendix to contain luminal air. Mesenteric lymphadenopathy is sometimes apparent but can be confused with mesenteric adenitis in children. Most authorities have stated that the normal appendix can be visualized by ultrasonography less than 5% of the time; therefore, it is easier to establish the diagnosis of appendicitis than to exclude it.
You can find best pharmacy with finest quality medications available round the clock right now: all you need to do is buy tadalafil online discovering the amazing opportunities you are being offered.
There has been considerable discussion about appendiceal diameter, the most widely used diagnostic criterion. Most authorities use a threshold of 6 or 7 mm for appendicitis, and dilation is often quite obvious. A dilated appendix is not, however, a specific sign of appendicitis, because the healthy appendix can dilate in the presence of metabolic disturbances or inflammatory processes elsewhere in the abdomen or pelvis. An appendiceal wall diameter of 3 mm or greater may be more predictive, but effacement of the wall of a very dilated appendix may occur just before rupture. Moreover, a dilated noncompressible appendix is much less frequently seen after perforation, probably because of collapse or even disintegration. For this reason, sonography is actually less able to detect perforated than nonperforated acute appendicitis, although the recent use of more refined techniques has partially overcome this problem.