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

Recon 1
NameColo_prone 1.0 B10f
Slice Thickness1.0mm
Increment0.7mm
KernelB10f very smooth
WindowingAbdomen

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

Recon 1
NameColo_supine IV 1.0 B20f
Slice Thickness1.0 mm
Increment0.7 mm
KernelB20f smooth
WindowingAbdomen

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