How Important Is Reviewer Experience in Diagnosing Small Bowel Obstruction?

When it comes to reading abdominal radiographs, does reviewer experience matter?

A recent study was conducted to determine if abdominal radiography is accurate in diagnosing small bowel obstruction (SBO). It also set out to try to determine the role of reviewer experience in diagnosing small bowel obstruction, and to evaluate radiographic findings of small bowel obstruction.

The study found that the more experienced the radiologist, the more accurate the diagnosis of small bowel obstruction.

The Study
90 patients (49 women and 41 men) with suspected SBO.

Methodology
All patients underwent CT and abdominal radiography within 48 hours of each other. The diagnosis of SBO was made in 29 patients with surgery, and in 16 patients who had relief of obstructive symptoms after bedrest and nasogastric (NG) tube suction.

SBO was excluded if the patient was treated for another diagnosis and symptoms resolved, if symptoms resolved without NG tube suction, and if there was no persistent pain, abscess, or fever of unknown origin during the hospital stay.

Radiographs were reviewed by 3 groups of radiologists with training experience as follows:

• group 1 with 15 and 30 years
• group 2 with 4 and 5 years
• group 3 were second-year radiology residents.

The reviewers rated the quality of the study as well as whether there was evidence of SBO, and rated their level of confidence on a scale of 1 (low) to 5 (high). They also documented presence or absence of the following signs:

• >2 air-fluid levels
• air-fluid levels >=2.5 cm
• air-fluid levels of unequal heights in the same loop
• string-of-pearls sign
• gasless abdomen
• colonic dilatation
• gastric or duodenal dilatation,
• NG tube
• pneumoperitoneum
• portal venous air
• pneumobilia
• ascites
• abdominal mass.

Results
Not surprisingly, it was found that the senior staff members were statistically more accurate in detecting SBO on abdominal radiographs.
In addition, the following 3 radiographic signs were found to be highly significant in the detection of SBO:

• >2 air-fluid levels
• air-fluid levels >=2.5 cm
• air-fluid levels of unequal heights in the same loop.

Reviewer’s Comments
Abdominal radiography is an important way of evaluating patients for small bowel obstruction. In particular, this can be used as a screening exam in patients for whom a physician might consider obtaining a CT. It is also an inexpensive way to follow patients who have been treated for SBO.

In patients suspected of SBO, this article points out that CT can be viewed as a supplement rather than a substitute for conventional abdominal radiography.

One of the limitations of this study is that it was a retrospective study and, therefore, the reviewers had to choose only between a diagnosis of SBO and no SBO.

Author: John C. Sabatino, MD, MSD
Reference:
Thompson, William M., et al. Accuracy of Abdominal Radiography in Acute Small-Bowel Obstruction: Does Reviewer Experience Matter?
AJR 2007; 188:W233-W238