CT protocol of Spine

CT Procedure Of Spine

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