Last Updated on January 19, 2023 by Mohamad Izwan
Anatomy of Colon
Image taken from teachmeanatomy.info
Appearance of Colon in Axial CT Image
CT Colon Non Contrast (Prone)
CT Colon Post Contrast (Supine)
Examination Overview
Protocol Structure
00_Colonography (Adult)
Prone
- Topogram
- Colon Prone
Contrast
Supine
- Topogram
- Colon Supine
Patient Orientation Registry in System
- Set the orientation patient in system: Head First – Prone
Topogram Prone
- Position the patient in head first prone position.
- Align the patient in Mid-Sagittal plane of the table.
- Raised patient’s both arms above head.
- Position the transverse laser light beam at the level of patient’s nipple line to start the abdominal topogram.
- Pump-in air into the colon until patient feel discomfort.
Topogram Parameters
- Topogram length: 512 cm
- Slice: 0.6 mm
- Scanning direction: Craniocoudal
- Tube position: Top
- Stop the topogram scanning when the scanning reach / pass over the inferior ischial ramus.
Non Contrast
- Plan the Scan FOV (SFOV) box at topogram image
- Set the top line at the level of above diaphragm
- Set the bottom line at the level of inferior ischial ramus.
- Ensure the lateral line to cover patient’s body outline.
- Remind the patient before scanning as the breathing instruction will be given.
Scanning Parameters
- kVp:
- mAs: Tube Current Modulation (TCM)
- Scanning Direction: Craniocaudal
- Scan Delay: 4 s
- Slice:0.6
- Image Comment: Non Contrast
- Pitch: 0.6
Reconstruction of Non Contrast
Contrast
Type of contrast used:
- Non-ionic iodinated contrast media
- 300 I mg/mol
Needle Placement Test:
- Flow Rate: 3.5 ml/sec
- Volume of Normal Saline: 15 ml
Contrast Injection:
- Volume of Contrast Media: 100 ml (depend on patient’s body habitus)
- Volume of Normal Saline: 50 ml
- Method of injection: Contrast Injector
- Flow Rate:
- Contrast: 3.0 ml/sec
- Normal Saline: 3.0 ml/sec
Post Contrast Scan Planning
Patient Orientation Registry in System
- Set the orientation patient in system: Head First – Supine
Topogram Supine
- Position the patient in head first supine position.
- Align the patient in Mid-Sagittal plane of the table.
- Raised patient’s both arms above head.
- Position the transverse laser light beam at the level of patient’s nipple line to start the abdominal topogram.
- Pump-in air into the colon until patient feel discomfort.
Colon Post Contrast
- Plan the Scan FOV (SFOV) box at topogram image.
- Set the top line at the level above the diaphragm.
- Set the bottom line at the level of inferior ischial rami.
- Ensure the lateral line to cover patient’s body outline.
- Remind the patient before scanning as the breathing instruction will be given.
- Scan delay after contrast injection: 65 sec.
Reconstruction of Colon Post Contrast
Multiplanar Reconstruction (MPR)
Parallel Ranges:
Image thickness : 3.0 mm
Number of images : 19
Colon IV:
Coronal abdomen IV (supine position)
Siemens SyngoVia 3D Render
- Open the series of images using ‘CT Colon’
- Select ‘Double Contrast’
- Select ‘Hide’
- At the right upper corner of the viewer, press ‘Show/Hide flight path’
- Open ‘Ranges Tools’ and select ‘Radial ranges’
Radial Ranges
Number of images : 19 (lock)
Angle between images : 19 degree
Save as VRT Range CT Colon
Series of Images Send to PACS
- Topogram 0.6 T20f (prone)
- Colo_prone 1.0 B10f
- Topogram 0.6 T20f
- Colo_supine IV 1.0 B20f
- Patient Protocol
- VRT Range CT Colon
