An appendix ultrasound is a non-invasive imaging technique that uses sound waves to examine the appendix and surrounding abdominal structures. It helps assess abdominal pain, particularly when appendicitis is suspected. This initial diagnostic step is preferred for children and pregnant individuals due to its lack of radiation. The scan’s primary goal is to identify abnormalities.
Key Indicators of Abnormality
Radiologists look for specific visual cues of abnormality during an appendix ultrasound. A significant indicator is the appendix diameter; typically, an outer diameter greater than 6 millimeters is considered abnormal. An inflamed appendix often appears aperistaltic, lacking normal contractions, and is frequently non-compressible under transducer pressure. The wall of an inflamed appendix may also appear thickened, often exceeding 3 millimeters.
Inflammation around the appendix can manifest as periappendiceal fluid or fat stranding. Periappendiceal fat stranding appears as increased brightness of the surrounding fat, indicating inflammation. The presence of an appendicolith, a calcified deposit within the appendix lumen, is another notable finding, appearing as a hyperechoic structure with posterior acoustic shadowing. Additionally, an inflamed appendix might display a “target sign” on a transverse view, characterized by concentric layers of the thickened and inflamed appendiceal wall.
Conditions Diagnosed
Abnormal ultrasound findings often point to specific medical conditions. Acute appendicitis is the most common diagnosis, indicated by a combination of the previously mentioned signs, such as a dilated, non-compressible appendix with thickened walls and surrounding inflammation. This condition involves inflammation of the appendix, usually resulting from an obstruction of its lumen. The inflamed appendix may also show increased blood flow within its wall on Color Doppler imaging, especially in early stages.
Sometimes, inflammation can progress to form an appendiceal abscess, which appears on ultrasound as a fluid collection in the appendiceal region. This collection can be well-defined or irregular, and occasionally, the appendix itself might be visible within the mass. Another possible finding is a phlegmon, which is a localized area of inflammation and thickening of tissues around the appendix, but without a distinct collection of pus. It can be seen as severe periappendiceal fat stranding and ill-defined fluid. Rarely, an ultrasound might reveal an appendiceal tumor, which may present as an enlarged appendix exceeding 15 mm in diameter, or intussusception, where one part of the intestine slides into another.
Beyond the Scan: Next Steps
Once abnormal findings are identified, further evaluation is necessary. Clinical correlation, which involves considering the patient’s symptoms, physical examination results, and blood tests, is essential to complement the imaging findings. Blood tests, such as white blood cell count (WBC) and C-reactive protein (CRP), help assess the level of inflammation. If acute appendicitis is confirmed, surgical removal of the appendix, known as an appendectomy, is the standard treatment.
Appendectomies can be performed either through open surgery, involving a single larger incision, or more commonly, through a laparoscopic approach using several smaller incisions. Laparoscopic surgery generally leads to less pain, reduced scarring, and a quicker recovery period. In cases where the appendix has ruptured and an abscess has formed, an initial drainage procedure might be performed, sometimes followed by a delayed appendectomy weeks later. For very mild cases of appendicitis or other specific findings, non-surgical management with antibiotics might be considered, though there is a higher chance of recurrence if the appendix is not removed.