MDCT in Emergency Radiology: Is a Standardized Chest or Abdominal Protocol Sufficient for Evaluation of Thoracic and Lumbar Spine Trauma?

MDCT in Emergency Radiology: Is a Standardized Chest or Abdominal Protocol Sufficient for Evaluation of Thoracic and Lumbar Spine Trauma?

Justus E. Roos¹, Paul Hilfiker¹, Andreas Platz², Lotus Desbiolles¹, Thomas Boehm¹, Borut Marincek¹ and Dominik Weishaupt¹

¹ Institute of Diagnostic Radiology, University Hospital Zurich, Raemistrasse 100, Zurich 8091, Switzerland.
² Division of Trauma Surgery, University Hospital Zurich, Zurich 8091, Switzerland.

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Fig. 1. —Scheme shows postprocessing of raw data acquired with standardized 4-MDCT trauma protocol. Reconstruction and postprocessing of data acquired with standardized 4-MDCT trauma protocol included three steps: First, volume data set acquired with collimation of 4 x 2.5 mm (middle) is reconstructed with a slice width of 3 mm and reconstruction interval of 2 mm with medium smooth kernel (B30). Second, multiplanar reformations (left) are reconstructed from whole data set and magnified on workstation screen. Finally, axial images targeted to spine (right) just covering entire vertebral column are secondarily reconstructed with slice width of 3 mm and reconstruction interval of 1.5 mm with bone edge-enhancement kernel (B50). Image analysis was based on interpretation of axial source images, images targeted to spine, and multiplanar reformations.

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Fig. 2A. —31-year-old woman who presented after 3-m fall with burst fracture of second lumbar vertebra. We compared image quality between standardized 4-MDCT trauma protocol (4 x 2.5 mm collimation) and thin-section spinal protocol (4 x 1 mm collimation). Axial 4-MDCT scan obtained as part of standardized trauma protocol (4 x 2.5 mm collimation) shows fracture line crossing vertebral body (arrowhead) and extending into left lamina (arrow) close to articular mass of facet joint. Image quality was rated excellent (score of 4).

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Fig. 2B. —31-year-old woman who presented after 3-m fall with burst fracture of second lumbar vertebra. We compared image quality between standardized 4-MDCT trauma protocol (4 x 2.5 mm collimation) and thin-section spinal protocol (4 x 1 mm collimation). Axial thin-section CT scan obtained using standard-of-reference protocol (4 x 1 mm collimation) shows this image depicts fracture with image quality identical to A. Fracture line can be seen crossing vertebral body (arrowhead) and extending into left lamina (arrow).

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Fig. 2C. —31-year-old woman who presented after 3-m fall with burst fracture of second lumbar vertebra. We compared image quality between standardized 4-MDCT trauma protocol (4 x 2.5 mm collimation) and thin-section spinal protocol (4 x 1 mm collimation). Sagittal multiplanar reformation image based on standardized 4-MDCT trauma protocol (4 x 2.5 mm collimation) shows anterior (arrow) and posterior (arrowheads) fracture fragments of vertebral body, with latter compressing spinal canal. Image quality was rated good (score of 3).

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Fig. 2D. —31-year-old woman who presented after 3-m fall with burst fracture of second lumbar vertebra. We compared image quality between standardized 4-MDCT trauma protocol (4 x 2.5 mm collimation) and thin-section spinal protocol (4 x 1 mm collimation). Sagittal multiplanar reformation image based on thin-section spinal CT protocol (4 x 1 mm collimation) confirms location of fracture fragments as discussed in C. Image quality was rated good to excellent (score of 3.75).

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Fig. 3A. —58-year-old woman presenting with Chance fracture of second lumbal vertebra due to car wreck. Fracture was not visible on axial images. Sagittal multiplanar reformation image based on standardized 4-MDCT trauma protocol (4 x 2.5 mm collimation) depicts fracture line (arrowheads) running horizontally through osseous structures of entire vertebra.

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Fig. 3B. —58-year-old woman presenting with Chance fracture of second lumbal vertebra due to car wreck. Fracture was not visible on axial images. Sagittal multiplanar reformation image based on thin-section spinal CT protocol (4 x 1 mm collimation) shows same fracture course (arrowheads) as A dissecting vertebra.

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Fig. 3C. —58-year-old woman presenting with Chance fracture of second lumbal vertebra due to car wreck. Fracture was not visible on axial images. Coronal multiplanar reformation image reconstructed with standardized 4-MDCT trauma protocol (4 x 2.5 mm collimation) reveals fracture (arrowheads) involves posterior elements on both sides equally.

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Fig. 3D. —58-year-old woman presenting with Chance fracture of second lumbal vertebra due to car wreck. Fracture was not visible on axial images. Coronal multiplanar reformation image reconstructed with thin-section spinal CT protocol (4 x 1 mm collimation) confirms extent of fracture (arrowheads) in posterior column.

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Fig. 4A. —30-year-old man who presented with unstable translation injury of fifth thoracic vertebra after car crash. Sagittal multiplanar reformation image based on standardized 4-MDCT trauma protocol (4 x 2.5 mm collimation) shows anterior translation of upper vertebrae with respect to lower vertebrae, compressive failure of anterior column of lower vertebral body (arrow), disruption of posterior column with facet dislocation (single arrowhead), and small fracture fragments in posterior column (double arrowheads).

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Fig. 4B. —30-year-old man who presented with unstable translation injury of fifth thoracic vertebra after car crash. Sagittal multiplanar reformation image based on thin-section spinal CT protocol (4 x 1 mm collimation) verifies fracture type with its anterior translation component (arrow) and its facet dislocation (single arrowhead) and small fracture fragments in posterior column (double arrowheads). Although better image quality is obvious with this protocol, no other relevant information is achievable if compared with standardized 4-MDCT trauma protocol.

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Fig. 5A. —68-year-old man with subtle anterior wedge compression fracture of 12th thoracic vertebra from bicycle accident. Coronal multiplanar reformation image obtained with standardized 4-MDCT trauma protocol (4 x 2.5 mm collimation) does not allow depiction of subtle compression of cancellous bone. Therefore, both observers missed this fracture using standardized 4-MDCT trauma protocol.

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Fig. 5B. —68-year-old man with subtle anterior wedge compression fracture of 12th thoracic vertebra from bicycle accident. In contrast to A, this coronal multiplanar reformation image based on thin-section spinal CT protocol (4 x 1 mm collimation) reveals slight compression fracture of cancellous bone involving anterior column of vertebra (arrowheads).

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Fig. 6. —Box plots show median of summarized mean values of image quality rating based on axial source images and multiplanar reformations (MPR) using thin-section (4 x 1 mm collimation) and standardized (4 x 2.5 mm collimation) 4-MDCT trauma protocols. Each box plot ranges from 25th to 75th percentile. Minimum and maximum values are indicated by short horizontal lines. Standardized 4-MDCT trauma protocol (4 x 2.5 mm collimation) shows significantly reduced image quality for multiplanar reformation images compared with thin-section spinal protocol (p < 0.001), whereas difference between both protocols with regard to axial images was not statistically significant (p > 0.061).

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