Computed tomography compared to magnetic resonance imaging in occult or suspect hip fractures. A retrospective study in 44 patients.

BACKGROUND

Computed tomography (CT) for evaluation of occult and suspect hip fractures has been proposed as a good second-line investigation. The diagnostic precision compared to magnetic resonance imaging (MRI) is unclear.

PURPOSE

To compare the diagnostic performance of CT and MRI in a retrospective study on patients with suspect and occult hip fractures.

MATERIAL AND METHODS

Forty-four elderly consecutive patients with low-energy trauma to the hip were identified where negative or suspect CT was followed by MRI. Primary reporting and review by two observers as well as the diagnostic performance of the two modalities were compared. Surgical treatment and clinical course were used as outcomes.

RESULTS

Compared to the primary reports, the CT reviewers found fewer normal and no suspect cases. MRI changed the primary diagnoses in 27 cases, and in 14 and 15 cases, respectively, at review. There was no disagreement on MRI diagnoses.

CONCLUSION

In our patient population, MRI was deemed a more reliable modality for hip fracture diagnosis in comparison to CT. For clinical decision making, MRI seems to have a higher accuracy than CT. A negative CT finding cannot completely rule out a hip fracture in patients where clinical findings of hip fracture persevere.

KEY POINTS

• Experience is highly influential in diagnosing occult or suspect hip fractures at CT • Inconclusive hip CT shows high inter-rater reliability at experienced review • There was low diagnostic accuracy via CT compared to MRI for all interpreters • Hip fractures can readily be diagnosed at MRI regardless of radiological experience.