4 common errors in pediatric abdominal radiography

Pediatric radiology faces many of the same challenges inherent to pediatric specialties but the varied age and size of patients and lack of patient cooperation are especially problematic for imaging.

While advanced modalities aren’t necessarily rare in pediatric imaging, x-ray is by far the most commonly used modality.  However, studies have shown a wide range in sensitivity and specificity, indicating the difficulty and uncertainness of diagnostic pediatric radiology.

A group of researchers from Seattle Children’s Hospital at the University of Washington wanted to change that, publishing an overview of common errors in the American Journal of Roentgenology.

1. Bowel Gas Patterns

Presentation of bowels varies widely among children and adults alike, but children present some unique challenges. Inguinal hernia are one of the most common reasons for surgery in infants and children, usually presenting as bowel obstruction. Measuring bowel dilation can be difficult, however, as some children develop faster or slower than others.

It’s important to always characterize the level of obstruction, measuring bowel dilation as compared to the combined height of the L1 and L2 vertebral bodies—if it’s less than the combined measurement, it’s considered to be a normal diameter.

Bowell loop displacement or a gasless abdomen also raise the specter of an abdominal mass, according to the study.

2. Peritoneal Cavity

The peritoneal cavity, a space between the abdominal wall and the internal organs, can fill with air or fluid for a variety of reasons. This condition is called pneumoperitoneum, and pediatric radiologists should be familiar with common locations and presentations of the condition, especially in critically ill children.

“As a rule of thumb, the soft-tissue attenuation of the liver on a radiograph of a patient in a supine position should be homogeneous,” wrote lead author and Seattle-area radiologist Sarah Menashe, MD, et al. “The presence of sharp interfaces delineating central regions of hypodensity should raise concern for pneumoperitoneum.”

3. Calcifications

While calcification is common in adults the same cannot be said for pediatric patients. Arterial calcification is a relatively common and incidental condition, but calcification in pediatric patients is an indication of more serious problems.

“Unlike in adults, in whom soft-tissue calcifications are often related to senescent changes or incidental findings, abdominal calcifications are frequently associated with pathology in pediatric patients and often require further investigation,” wrote Menashe et al. “As such, both their presence and location should be documented.”

Complications with catheter placement via the umbilical cord can cause thrombosis, often seen along the expected course of the catheter, the authors wrote. 

4. Bones

Bone pain is a common condition in pediatrics that usually turns out to be benign, but diagnosis can be challenging due to vague symptoms and the difficulty of obtaining a detailed history from children, causing pediatric physicians to turn to imaging.

“In the setting of vague symptoms and referred pain, a chest or abdominal radiograph is often the first imaging study obtained,” wrote Menashe et al. “Visualized bony structures should be evaluated for integrity as well as for the presence of lytic or sclerotic bony lesions or simply abnormal bone density.”

Oddly enough, a diagnosis of constipation can be affected by the appearance of bones—specifically, the sacrum.

Constipation without cause affects 3 percent of the pediatric population worldwide, with as many as 40 percent of these cases presenting by one year of age. One possible explanation is a rare condition called Currarino syndrome, characterized by the absence of most of the sacrum and causing severe constipation.

“When a child undergoes abdominal radiography for constipation, one must be certain to assess sacral integrity,” the authors wrote.