SAN FRANCISCO — While imaging isn't necessary in obvious cases of pediatric appendicitis, CT or ultrasound can be of great help in making a diagnosis, Hanmin Lee, M.D., said at a meeting on clinical pediatrics sponsored by the University of California, San Francisco.
The 10-year-old boy with right lower quadrant pain, McBurney sign, a slightly elevated blood count, and a low-grade fever can go straight to the operating room, said Dr. Lee of the university.
In other cases, imaging can be a very important aid to decision making.
Plain x-ray films are usually not too helpful except in one case: a chest x-ray can be useful to rule out right lower lobe pneumonia, especially if the child has some suggestive symptoms.
Both CT and ultrasound can be excellent diagnostic tools, and which to use often depends on institutional factors. CT tends to be more consistent from one institution to another, and as a static image, it's easier for a third party to read.
Ultrasounds are more variable but can have the twin advantages of less time and expense, he said.
There are patient differences, however. “In a younger skinnier patient, an ultrasound is probably better,” Dr. Lee said. “In an older heavier patient, CT scan is probably better.”
Ultrasound and CT studies that come back “positive” can be relied on to be accurate, he said. But clinicians should quiz the radiologist with a study that comes back “negative.”
If “negative” means that a normal appendix has been identified, that's probably accurate. But often “negative” actually means that the appendix has not been seen. This result would more accurately be called “indeterminate,” Dr. Lee said.
With CT, a clear positive would be a thickened tubular structure that filled with contrast. With ultrasound, a clear positive would be an incompressible, thick-walled, tubular structure, he said.