Are conventional inlet and outlet radiographs obsolete in the evaluation of pelvis fractures?

INTRODUCTION

The new-generation multidetector computed tomographic (CT) scanners allow for the generation of virtual x-rays from the data acquired during the evaluation of pelvic fractures. Special software allows technicians to obtain the appropriate orientation required for adequate inlet and outlet views, which would eliminate repeat trips to the radiography suite to acquire adequate x-rays. The purpose of this study is to compare the quality virtual x-rays and conventional x-rays that are used in evaluating pelvis fractures.

METHODS

A retrospective database review was performed to identify patients who were operated on with a diagnosis of pelvis fracture. The inclusion criteria were AO/OTA type B or C pelvic fractures, age older than 18 years, complete set of anteroposterior (AP) pelvis, inlet, and outlet x-rays and a multidetector pelvis CT scan. Virtual AP pelvis, inlet, and outlet views were generated from the CT scan data. Two fellowship-trained orthopedic trauma surgeons reviewed the virtual and conventional studies separately in association with CT scans and graded the quality of the studies on a custom developed questionnaire.

RESULTS

Twenty patients were eligible for the study. The AP pelvis image quality was similar for both conventional and virtual images except for the rotation of the pelvis, which was improved in the virtual images. The inlet and outlet image quality was better in all domains in the virtual x-ray group when compared with the conventional x-rays. The percentage of adequate inlet and outlet images was higher in the virtual x-ray group when compared with the conventional x-ray group.

DISCUSSION

The results show that the virtual inlet and outlet images consistently provided higher rates of adequate x-rays when compared with the conventional x-rays. In the evaluation of patients with pelvis fractures, the use of the virtual inlet and outlet views instead of the conventional x-rays may provide some advantages, such as decreased radiation exposure to the patient, reduced overall cost, and reduced repeat x-rays to achieve adequate views.

LEVEL OF EVIDENCE

Diagnostic study, level V.