This document provides guidelines for CT imaging of the spine, including patient positioning, scan parameters, and indications. It describes the anatomy of the spine, noting the typical diameters of the cervical spinal cord. It provides details on positioning patients for cervical, thoracic, and lumbar spine scans. Scan parameters covered include mode, field of view, slice thickness, reconstruction algorithms. Contrast administration for intravenous and intrathecal contrast is also outlined.

1. CT Protocol Of Spine
Subodh Dhungana
Chitwan Medical College

2. Anatomy of Spine
• AP diameter is 7mm through C7
• C7 to conus medullaris is 6mm
• At conus it is 7mm
• Cord size is considered abnormal if it is over 8mm or under 6mm
• Number of Vertebra:
• Cervical vertebra-C1 to c7
• Thoracic vertebra-T1 to T12
• Lumbar Vertebra-L1 to L5
• Sacral-5 fused
• Coccyx- 4 fused

3. Axial Anatomy of Cervical Spine

4. Axial Anatomy Of Thoracic Spine

5. Axial Anatomy Of Lumbar Spine

6. CT Image Of Whole Spine

7. Indications:
• Suspected occult fractures
• Complex fractures
• Pre-operative baseline evaluation and post surgical evaluation
• Bony or soft tissue masses
• Spondylolisthesis
• Disk disease especially when MR is contraindicated
• CT Myelography

8. • Patient Positioning:
• For cervical spine- Supine with head first, arms by the side of the trunk and
tucked below the hips to bring the shoulder down
• For Dorsal and Lumbar Spine- Supine with Head first, arms elevated above the
head, knees in partial extension
• Topogram/Landmark:
• Lateral; landmark is decided by the radiologist or radiographer to include the
anatomic region of interest

9. • Mode of Scan:
• Helical
• Scan Orientation:
• Start Location: Middle part of the body of the vertebra above the cranial limit
of the vertebral level of interest
• End Location: Middle part of the body of the vertebra below the caudal limit
of the vertebral level of interest
• Gantry Tilt: Nil
• Field Of View:
• Just fitting the region of interest including the pre and paravertebral tissues

10. • Contrast Administration:
• Intravenous (optional-in case of mass lesions) and Intrathecal for
myelographic studies
• Volume Of Contrast:
• 80-100ml Intravenous; 10-15ml Intrathecal
• Rate Of Injection Of Contrast:
• 2-3mlml/sec for Intravenous; slow over a period of 2-3 minutes for Intrathecal
• Scan Delay:
• 40-50 sec for Intravenous; 10-20 minutes for Intrathecal

11. • Slice Thickness In Reconstruction: 2-4 mm
• Slice Interval In Reconstruction: 1.0-2.0 mm
• Reconstruction Algorithm/Kernel:
• Sharp for Bone and Medium smooth for soft tissues
• 3D-Reconstruction:
• MPR, thick and thin MIP, SSD

12. Comments:
• Remove the dentures, prosthesis and necklaces before positing for
the cervical spine
• MPR images are prepared in the plane of the region of interest or the
pathology detected while scanning. While preparing the MPR images
for the disk lesions, the plane of reconstruction should be parallel to
the disk of interest preferably 1-2mm thick. Sagittal MPR are
mandatory.
• For craniovertebral region, the slice thickness should preferably be 1-
2mm with the slice interval of 0.5mm. Coronal MPR images are
equally important as the Sagittal images in this region.

13. Criteria Of Good Image Quality:
• Absence of Beam hardening
• Absence of motion artefacts
• Uniform Contrast density in the thecal sac in case of myelographic
study