Stereoscopic 3D CT vs standard 3D CT in the classification of acetabular fractures: an experimental study

Evaluation of the diagnostic accuracy of four-view radiography and conventional computed tomography analysing sacral and pelvic fractures in dogs

OBJECTIVE

The purpose of our study was (1) to determine whether four-view radiography of the pelvis is as reliable and accurate as computed tomography (CT) in diagnosing sacral and pelvic fractures, in addition to coxofemoral and sacroiliac joint subluxation or luxation, and (2) to evaluate the effect of the amount of training in reading diagnostic imaging studies on the accuracy of diagnosing sacral and pelvic fractures in dogs.

METHODS

Sacral and pelvic fractures were created in 11 canine cadavers using a lateral impactor. In all cadavers, frog-legged ventro-dorsal, lateral, right and left ventro-45°-medial to dorsolateral oblique frog leg ("rollover 45-degree view") radiographs and a CT of the pelvis were obtained. Two radiologists, two surgeons and two veterinary students classified fractures using a confidence scale and noted the duration of evaluation for each imaging modality and case. The imaging results were compared to gross dissection.

RESULTS

All evaluators required significantly more time to analyse CT images compared to radiographic images. Sacral and pelvic fractures, specifically those of the sacral body, ischiatic table, and the pubic bone, were more accurately diagnosed using CT compared to radiography. Fractures of the acetabulum and iliac body were diagnosed with similar accuracy (at least 86%) using either modality.

CLINICAL SIGNIFICANCE

Computed tomography is a better method for detecting canine sacral and some pelvic fractures compared to radiography. Computed tomography provided an accuracy of close to 100% in persons trained in evaluating CT images.

Evaluation of the Diagnostic Accuracy of Conventional 2-Dimensional and 3-Dimensional Computed Tomography for Assessing Canine Sacral and Pelvic Fractures by Radiologists, Orthopedic Surgeons, and Veterinary Medical Students

OBJECTIVE

To determine, using 3 groups of evaluators of varying experience reading orthopedic CT studies, if 3-dimensional computed tomography (3D-CT) provides a more accurate and time efficient method for diagnosis of canine sacral and pelvic fractures, and displacements of the sacroiliac and coxofemoral joints compared with 2-dimensional computed tomography (2D-CT).

STUDY DESIGN

Retrospective clinical and prospective study.

ANIMALS

Dogs (n = 23): 12 dogs with traumatic pelvic fractures, 11 canine cadavers with pelvic trauma induced by a lateral impactor.

METHODS

All dogs had a 2D-CT exam of the pelvis and subsequent 3D-CT reconstructions from the 2D-CT images. Both 2D-CT and 3D-CT studies were anonymized and randomly presented to 2 veterinary radiologists, 2 veterinary orthopedic surgeons, and 2 veterinary medical students. Evaluators classified fractures using a confidence scale and recorded the duration of evaluation for each modality and case.

RESULTS

3D-CT was a more time-efficient technique for evaluation of traumatic sacral and pelvic injuries compared with 2D-CT in all evaluator groups irrespective of experience level reading orthopedic CT studies. However, for radiologists and surgeons, 2D-CT was the more accurate technique for evaluating sacral and pelvic fractures.

CONCLUSION

3D-CT improves sacral and pelvic fracture diagnosis when added to 2D-CT; however, 3D-CT has a reduced accuracy for evaluation of sacral and pelvic fractures if used without concurrent evaluation of 2D-CT images.

A guide to stereoscopic 3D displays in medicine

Stereoscopic displays can potentially improve many aspects of medicine. However, weighing the advantages and disadvantages of such displays remains difficult, and more insight is needed to evaluate whether stereoscopic displays are worth adopting. In this article, we begin with a review of monocular and binocular depth cues. We then apply this knowledge to examine how stereoscopic displays can potentially benefit diagnostic imaging, medical training, and surgery. It is apparent that the binocular depth information afforded by stereo displays 1) aid the detection of diagnostically relevant shapes, orientations, and positions of anatomical features, especially when monocular cues are absent or unreliable; 2) help novice surgeons orient themselves in the surgical landscape and perform complicated tasks; and 3) improve the three-dimensional anatomical understanding of students with low visual-spatial skills. The drawbacks of stereo displays are also discussed, including extra eyewear, potential three-dimensional misperceptions, and the hurdle of overcoming familiarity with existing techniques. Finally, we list suggested guidelines for the optimal use of stereo displays. We provide a concise guide for medical practitioners who want to assess the potential benefits of stereo displays before adopting them.