Colon: Virtual colonoscopy

Specific Anatomic Region	Colon
Application	Virtual colonoscopy
Author	Fishman EK
Reference Source	Personal Communication
Scanner Used	Siemens Plus4 Volume Zoom
KV / mAs / Time per Rotation (sec)	120 / 165 / .5
Detector Collimation (mm)	1 or 2.5
Slice Thickness (mm)	1.25 or 3
Data Reconstruction Interval (mm)	1 or 3
Table Speed (mm per rotation) / Pitch	6 / 6 or 15 / 6
Oral Contrast	N/A (rectal air only)
IV Contrast Volume and Type	N/A or IV contrast
Injection Rate	N/A or 2-3 cc/sec
Scan Delay (sec)	N/A or 30 sec
3D Technique Used	MPR and Volume rendering
Comments: The optimal protocols have not yet been defined. A lower dose study can be done using 120 / 110 / .5 with a pitch of 6 (12 mm / sec travel). Low dose will be important if virtual colonoscopy becomes a screening tool. We like to use IV contrast as it makes it easier to detect the presence of polyps. Prone and supine images are needed in all cases.