Problem-solving with MRI in acute abdominopelvic conditions, part 1: gastrointestinal, hepatobiliary, and pancreatic diseases

MRI as an alternative to CT after inconclusive ultrasound in subacute/acute abdominal pain in young women: a prospective multicenter noninferiority study

OBJECTIVE

To assess the noninferiority of MRI diagnostic accuracy to CT scan as a second-line examination of acute/subacute abdominopelvic pain in a population of young women after an inconclusive ultrasound (US).

METHODS

This prospective, multicenter non-inferiority study included 18-40-year-old non-pregnant women with non-traumatic acute/subacute abdominal pain. They had an inconclusive US warranting the prescription of an additional CT scan. Within 6 h of the CT, all these women underwent abdomino-pelvic MRI. A retrospective reading of the CT and MR provided a diagnosis using a standardized list. The gold standard diagnosis, based on a 3-month follow-up, was done by a panel of experts. Statistical analysis was conducted to assess the noninferiority of the diagnostic accuracy of MRI compared to that of CT. The noninferiority margin was set at 10%. Inter-observer agreement and diagnostic performance of a conditional imaging strategy were estimated.

RESULTS

133 participants were analyzed (median: 27 years). The most common diagnoses were non-specific pain (30.1%), ovarian cyst rupture (12.8%), and appendicitis (9.7%). MRI demonstrated non-inferiority diagnostic accuracy estimated between 60.9% (81/133) and 88% (117/133) compared to CT, estimated between 64.7% (86/133) and 83.5% (111/133). The conditional imaging strategy (MRI, followed by CT when the MRI was normal) had a diagnostic accuracy of 91%.

CONCLUSION

MRI diagnostic performances are not inferior to CT for acute abdominal pain in women aged 18-40. A conditional imaging strategy based on MRI would give an accuracy of 91% and might be considered a second-line imaging modality in that context.

KEY POINTS

Question Can MRI serve as an alternative to CT as a second-line imaging modality for acute abdominopelvic pain in young women (18-40) after an inconclusive ultrasound? Findings MRI accuracy after inconclusive US ranged from 60.9 to 88%. A conditional strategy (MRI first, CT if normal) reached 91% accuracy, avoiding 59% of CTs. Clinical relevance MRI is not inferior to CT for diagnosing uncategorized causes of acute abdomino-pelvic pain in young non-pregnant women. A conditional imaging strategy based on MRI as a second-line imaging modality would give an accuracy of 91%.

The Society for Pediatric Radiology Magnetic Resonance Imaging and Emergency and Trauma Imaging Committees' consensus protocol recommendation for rapid MRI for evaluating suspected appendicitis in children

The imaging evaluation of acute abdominal pain in children with suspected appendicitis has evolved to include rapid abdominopelvic MRI (rMRI) over recent years. Through a collaborative effort between the Magnetic Resonance Imaging (MRI) and Emergency and Trauma Imaging Committees of the Society for Pediatric Radiology (SPR), we conducted a survey on the utilization of rMRI to assess practice specifics and protocols. Subsequently, we present a proposed consensus rMRI protocol derived from the survey results, literature review, and discussion and consensus between committee members.