Upakar Paudel

1. B.Sc.MIT, 3rd Year
Roll No.: 6
UCMS BHAIRAHAWA

2. Outline
CT Procedure of Abdomen and Pelvis
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 Cross section anatomy
 Indications/Contraindications
 Patient preparation
 Technique
 Summary
 References

3. Cross Section Anatomy
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Gross structure inside the abdomen and pelvis:
 Liver, Gall bladder and Biliary tree, Pancreas, spleen
 Stomach, Duodenum, Small intestine, Colon
 Kidneys, ureters, bladder, uterus, ovaries, prostate
 Blood vessels, lymph nodes, peritoneum cavity,
muscles, boney structure etc.

4. Cross Section Anatomy
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5. Cross Section Anatomy
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6. Cross Section Anatomy
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7. Cross Section Anatomy
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Male Pelvis

8. Cross Section Anatomy
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Female Pelvis

9. Indications
 Screening, Control or Baseline Scans
Pathology
 Cyst
 Abscess
 Mass
 Tuberculosis
 Vascular lesion
 Calculus
 Lymphadnopathy
 Metastasis
 Trauma- rupture
Congenital anomalies- agenesis, ectopic
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10. Contraindications
Relative
 Hypersensitivity to iodinated contrast media
 Renal insufficiency
 Pregnancy
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11. Patient Preparation
 Nil Per Oral from 5-6 hours.
 Use laxative as well as water enema for colon examination.
 First explain all about examination and its complication to
patient.
 Take informed consent from patient or his/her close
relatives.
 Radiopaque material should be removed from area of
examination.
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12. Contrast Media
 Oral contrast: 750-1000ml of 1-2% Barium or water soluble
CM/plain water/ Air.
 Rectal contrast: 500-750 ml of 1-2% Diluted iodinated CM/Plain
water/ Air or CO2.
 IV contrast: Non ionic monomer( Iohexol, Ioversol,
Iopromide) 300-350mg or Nonionic Dimer. Dose: 100 to
150 ml.
 IV contrast is given by auto injector.
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13. Contrast Media
 Never give barium as a oral contrast in case of GI
perforation.
 Do not give positive oral contrast if vasculature needs to be
demonstrated by MIP.
 Now a days plain water is commonly used as oral contrast
in CT examination of abdomen.
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14. Bolus Tracking
 Technique used in CT to
visualize vessel more clearly
by use of Radiopaque CM
into patient.
 The volume of contrast is
tracked using ROI at a
certain level and followed
by CT once it reaches this
level.
 Generally the threshold
value is 150 HU in
abdominal aorta.
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15. Technique for Routine Abdomen and Pelvis
 Firstly, patient takes two third oral contrast from ½ to 1
hour for upper abdomen and 1 to 2 hour for lower
abdomen before examination.
 Then , one third oral contrast just before examination.
 Patient position: Head first, supine with arms extended
above the level of head.
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16. Technique for Routine Abdomen and Pelvis
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 Topogram position/landmark: AP,
from 2” above the Xiphisternum to 2”
below the Symphysis pubis.
 Mode of scanning: Plain and
enhanced in most of helical and in
some where axial.
 Scan orientation: Craniocaudal from
dome of diaphragm to Symphysis
pubis.
 FOV: Variable- Just fitting the
abdominal wall including sofr tissue.
 Contrast administration: As mentioned
above : Oral, Rectal and I/V.

17. Technique for Routine Abdomen and Pelvis
 Injection rate: 2-3 ml/sec
 Scan delay: 40-60 sec
 Slice thickness: 3-5 mm
 Slice interval : 1.5-2.5 mm
 Recon algorithm/Kernel:
Smooth medium
 3D reconstruction: MPR, MIP
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18. Modification in CT Technique of Abdomen
 There are some modification on CT technique depend upon
the pathology of different part inside abdomen.
 This modified technique are described as follows:
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19. CT of Stomach
 Plain water is used as oral contrast rather than the positive
oral contrast.
 About 500-600 ml plain water is given just before the
examination.(distention of stomach).
 Do the plain CT.
 CECT in venous phase in supine.
 Then do CT in prone, Rt. or Lt. Decubitus.
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20. CT of Stomach
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Source: CT & MRI of The Whole Body- John R. Haaga, Fifth Edition

21. Hepatic CT
 Plain water is used as oral contrast.
 Triphasic CT is performed for liver pathology.
 Arterial phase- hepatoma or focal nodular disease are
detected.
 Portal venous phase-
 Delayed phase- hemangioma are clearly seen.
 Area of scan from dome of diaphragm to iliac crest.
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22. Hepatic CT
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Source: CT & MRI of The Whole Body- John R. Haaga, Fifth Edition

23. Biliary CT
 Plain water is used as oral contrast.
 Role of plain CT is to detect stone.
 Area of scan from dome of diaphragm to iliac crest.
 Cholangiocarcinoma are detected in delay scan.
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24. Biliary CT
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Source: CT & MRI of The Whole Body- John R. Haaga, Fifth Edition

25. Biliary CT
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Source: CT & MRI of The Whole Body- John R. Haaga, Fifth Edition

26. CT of Pancreas
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 Plain water is used as oral contrast media which help to
distended C loop of duodenum.
 No oral contrast in case of pancreatitis.
 Area of scan from dome of diaphragm to iliac crest.

27. CT of Pancreas
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Source: CT & MRI of The Whole Body- John R. Haaga, Fifth Edition

28. CT of Pancreas
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Source: CT & MRI of The Whole Body- John R. Haaga, Fifth Edition

29. CT of Small Intestine
In general,
 Positive oral contrast about 1000 ml from 1 hrs.
 Non enhanced CT.
 After I/V contrast 100-150 ml.
1. Arterial phase- 25 to 30 sec
2. Venous phase- 55 to 60 sec
Now we perform CT Enteroclysis/Enterography for small
intestine.
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30. CT Enteroclysis
 In CT Enteroclysis, oral contrast is infusioned via
nasoenteric intubation.
 Various type of oral contrast used include water, water &
methylcellulose, lactulose.
 Nonenhanced CT perform in case of hemorrhage.
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31. CT Enterography
 In CT Enterography, oral contrast per orally.
 Various type of oral contrast used include water, water &
methylcellulose, lactulose.
 About 1- 2L from ½ to 1 hours before scanning.
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32. CT Enterography
 I/V cm is given at rate 3 ml/s to
obtained bowel enhancement.
 In MDCT, 1 mm or less slice
thickness is obtained.
 Generally do single phase(45-50s)
and sometime multiphase.
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Source: CT & MRI of The Whole Body-
John R. Haaga, Fifth Edition

33. CT Colon and Rectum
In general,
 Positive oral contrast about 1000 ml from 2 hrs and
rectal contrast air/plain water.
 Non enhanced CT.
 After I/V contrast 100-150 ml.
1. Arterial phase- 25 to 30 sec
2. Venous phase- 55 to 60 sec
Now we perform CT Colonography or virtual colonoscopy.
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34. CT Colonography
Bowel preparation :
 colonic purgation- sod. Phosphate and magnesium
citrate.
 fecal and fluid tagging- is method of labeling of
residual fecal and fluid remaining on colon by using
Radiopaque contrast agents.
 The contrast agent is orally administered at each meal,
typically the day before the CT Colonography.
Colonic distention:
 room air is used rather CO2 because rapid absorption
and painful.
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35. CT Colonography
 Inj. Buscopan20mg is given before air insufflations.
 Scanning in supine and prone position has shown a
superior colonic distention with slice collimation < 3mm.
 I/V contrast media is generally not required.
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Source: CT & MRI of The Whole Body- John R. Haaga, Fifth Edition

36. CT for Adrenal Gland
 Area of scan from dome of diaphragm to L3 level.
 Plain CT.
 After IV contrast media 125 ml at rate 3-4 ml, do following
phase.
 Arterial phase- 20 sec
 Parenchymal phase- 50-60 sec
 Delayed phase- 10 to 15 min
 Slice thickness- 3 mm
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37. CT for Adrenal Gland
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Source: CT & MRI of The Whole Body- John R. Haaga, Fifth Edition

38. CT for Kidneys
 Area of scan from dome of diaphragm to Symphysis pubis.
 Scan thickness- 1 to 3mm.
 Non enhanced phase- Plain CT
 Corticomedullary Phase- 25 to 70 sec
 Nephrographic Phase- 80 sec
 Excretory Phase- After 180 sec
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39. CT for Kidneys
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Source: CT & MRI of The Whole Body- John R. Haaga, Fifth Edition

40. CT Urography
 Now, CT Urography is another imaging technique for
urinary tract.
 In CT Urography, Kidneys, ureters and bladder are better
visualized.
 No need of oral contrast.
 First do plain CT and followed by CECT.
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41. CT Urography
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Source: CT & MRI of The Whole Body- John R. Haaga, Fifth Edition

42. CT Urography
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Source: CT & MRI of The Whole Body- John R. Haaga, Fifth Edition

43. CT Uterus/Ovaries
 Oral contrast one hour before examination.
 Rectal contrast just before examination.
 Nonenhanced CT
 IV contrast 300mg/ml about 100-150 ml.
 Arterial Phase- 25 to 30 sec
 Venous phase- 55 to 60 sec
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44. CT Technique for Abdominal Trauma
 Oral contrast is still controversy .
 Plain CT of Abdomen- to see hemorrhage.
 Area scanned- from diaphragm to Symphysis.
 Slice collimation- 2.5 to 3 mm.
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45. CT Technique for Abdominal Trauma
 Thickness reconstruction- 5 mm
 Volume of contrast -100 to 150 ml at rate of 2-3 ml/s.
 Scan after 70 sec of onset of injection.
 Delay scan after 3-5 min to see excretion from kidney.
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46. Film Printing Protocol
 Generally 5x5 mm If required thin section.
 Keep HU value on area of pathology both in Nonenhanced
and enhanced CT.
 Multiplanar reconstruction(MPR).
 3D VRT and MIP for vascular pathology.
 Windows level and centre-350/50 for soft tissue and
2200/400 for bone.
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47. Department Protocol
Upper Abdomen Protocol
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S.
N
.
Diagnosis
NCCT
(5x5
mm)
CECT
(5x5 mm)
Thin
sections
(3x3 mm)
MPR
(Sagittal
Coronal)
3D
1. Hepatic pathology - √ (Triple phase) √ √ -
2. Gastric pathology - √ (dual phase) √ √ -
3. Pancreatic
pathology
- √ (dual phase) √ √ -
4. Obstructive
jaundice
- √ (Triple phase) Thin
sections
(1.5x1.5
mm)
√ -
5. Any tumor - √ (Dual phase) √ √ -
6. Vascular pathology - CT angiography √ √ √

48. Department Protocol
Lower Abdomen Protocol
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S.N Diagnosis
Oral
Contras
t
Rectal
Contras
t
NCCT
(5x5
mm)
CECT
(5x5
mm)
Thin
section
(3x3 mm)
MPR
(Sagittal
+
Coronal)
3D
1. Colonic
pathology
√ √ - √ √ √ -
2. Gynaecolog
y pathology
√ √ √ √ √ √ -
3. Pelvic
tumor
√ √ - √ √ √ -

49. Department Protocol
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1. Unless particular small bowel pathology is suspected or
specified, plain water should be given as oral contrast for upper
GI and lower GI (colonic pathology).
2. For colon, if no obstruction, air should be given as rectal
contrast.
 Triple phase:
Arterial phase (20-30 sec), Portal Venous Phase (60-70 sec) &
Late Venous Phase (180 sec).
 CT Urography: Delayed films at 5 minute.
1. Unless specified, all films to be given as axial 5x5 mm along with
Sagittal and coronal MPR
2. Films for CT angiography: Axial, MPR & 3D
3. Contrast Dose:
a. Adult patient: 100 ml contrast with concentration of 300mg
Iodine/ml.
b. Children: 1.5 ml of contrast per kg body weight.

50. Summary
 CT has still superior role for abdomen imaging to detect
pathology despite of adverse effect and radiation effect.
 Never forget to see or ask history of patient under going
CT examination of abdomen.
 There are variations in CT protocols of different centre.
 Always use auto injector for I/V contrast media injection if
possible.
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51. References !!!
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 CT and MRI of whole body, Johan R. Hagga, Fifth edition.
 CT and MRI Protocol, Satish K. Bhargava
CT Teaching Manual, Matthias Hofer, Third edition.
 Step by Step CT scan, Karthikeyan & Chegu, First edition.

52. Questions ???
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 What are the contrast media used for CT Abdomen?
 What is oral and rectal contrast media?
 What is Bolus Tracking?
 What are the indication for CT abdomen?
 Describe the patient preparation for CT abdomen?
 Mention the Protocol for Hepatic CT?
 What is CT Urography?
 What are the modification for CT Stomach?

53. Thank You !!!
Thank You !!!