Results of a study by University of Vermont researchers suggest that 3T MRI should be considered as an alternative to CT in the evaluation of pediatric and young adult patients presenting to the emergency room with acute abdominal pain.

The Centers for Disease Control and Prevention recorded more than 100 million visits to emergency rooms in 2005, most of them due to abdominal pain. According to CDC data, a significant number of patients presenting with these symptoms underwent either ultrasound or CT scanning.

Recent studies have warned of an increased risk to the pediatric population due to CT overutilization. MR parallel imaging at 3T may be not only a safer bet than CT by keeping young patients from unnecessary ionizing radiation. It may also be more cost-effective, said coauthor Dr. Alisa K. Johnson.

"Pediatric patients who come to the emergency room with lower abdominal pain are often getting CTs," Johnson said in an interview with Diagnostic Imaging. "We are offering a fast, efficacious, and safe imaging modality with no ionizing radiation, no contrast, and no sedation."

Johnson and colleagues prospectively enrolled 23 patients with acute abdominal pain. Patients underwent free-breathing 3T parallel scanning with a 16-channel torso coil and short T1- and T2-weighted single-shot spin-echo sequences in three planes. All patients also had a CT and an ultrasound within 24 hours of MRI. Four radiologists interpreted studies in blinded fashion. Scan times ranged from two to seven minutes.

The 3T MR protocol accurately diagnosed 11 of 14 patients with true pathologies, which included abdominal abscesses, appendicitis, colitis, and mesenteric cysts. The investigators also found MR could help identify mesenteric adenitis, a mild condition that usually resolves without treatment. Johnson released her group's findings at the 2008 RSNA meeting.

MR time does not come cheaply, and researchers took that factor to heart when performing the study, Johnson said. Noncontrast scanning using a simple, fast sequence without sedation brings costs down considerably. It is also kind to patients in pain by avoiding breath-holds or ultrasound-like compression studies.

Patients avoid filling up with oral contrast, another plus for those with appendicitis, who might need to be rushed to the operating room, she said.

"Three-T MR is an excellent modality for evaluating acute abdominal pain for treatable conditions in children and adults," Johnson said. "It can diagnose multiple pathologies that cause right lower quadrant pain, which are often suspected as appendicitis."

Coronal T2-weighted 3T MR image of a seven-year-old patient with appendicitis. (Provided by A. Johnson)