<%@ Language=VBScript %> MDCT Protocols - Chapter 3. Imaging the Abdomen and Pelvis
   




 

 





Commentary:
1. Indicated for:
        • IBD (Crohn’s, ulcerative colitis)
        • Gynecological Pathology
        • Rectosigmoid mass
2. Oral contrast should be administered prior to the scan: 30 minutes before for the upper abdomen and
    60 to 90 minutes before for the whole body study.
3. Rectal contrast is useful for specific indications: gynecological pathology, rectosigmoid masses, and
    inflammatory bowel disease (IBD).
4. Provide patients with breathing instructions, as landmarks are prepared.
5. Take test cuts prior to scanning if there is a question about oral contrast opacification.
6. Perform routine abdomen-pelvis scans in one breath-hold.
7. If SmartPrep is used for scan delay, use the liver parenchyma and a 70 HU threshold.
8. For bladder and venous opacification, may stop at crest and scan pelvis after a 3-minute delay
    threshold for automated triggering.

Practical Considerations:

1. On 16-slice scanners, you may use a manual tube load (mA) or the auto mA (noise index and range)
     technique. With 64-slice scanners, AutomA is generally preferred.
2. Contrast volumes given are for patients of average weight and should be adjusted for each person’s body
    mass index (BMI).
3. Coupling high kVp with low mA is a strategy to decrease the radiation dose and prolong tube life.
4. Longer gantry rotation times are needed for larger patients when the maximum tube load is exceeded.
    If a patient is larger than average, consider increasing the scan time in order to increase the overall exposure level.