CT Procedure OF Abdomen & Pelvis

Upakar Paudel

1. CT PROCEDURE OF ABDOMEN & PELVIS UPAKAR PAUDEL B.Sc.MIT, 3 rd Year Roll No.: 6 UCMS BHAIRAHAWA

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

3. Cross Section Anatomy CT Procedure of Abdomen and Pelvis 3 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 CT Procedure of Abdomen and Pelvis 4

5. Cross Section Anatomy CT Procedure of Abdomen and Pelvis 5

6. Cross Section Anatomy CT Procedure of Abdomen and Pelvis 6

7. Cross Section Anatomy CT Procedure of Abdomen and Pelvis 7 Male Pelvis

8. Cross Section Anatomy CT Procedure of Abdomen and Pelvis 8 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 CT Procedure of Abdomen and Pelvis 9

10. Contraindications Relative Hypersensitivity to iodinated contrast media Renal insufficiency Pregnancy CT Procedure of Abdomen and Pelvis 10

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. CT Procedure of Abdomen and Pelvis 11

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 CO 2 . 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. CT Procedure of Abdomen and Pelvis 12

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. CT Procedure of Abdomen and Pelvis 13

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. CT Procedure of Abdomen and Pelvis 14

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. CT Procedure of Abdomen and Pelvis 15

16. Technique for Routine Abdomen and Pelvis CT Procedure of Abdomen and Pelvis 16 Topogram position/landmark : AP, from 2” above the X iphisternum to 2” below the Symphysis pubis. Mode of scanning : Plain and enhanced in most of helical and in some where axial. Scan orientation : C raniocaudal from dome of diaphragm to Symphysis pubis. FOV : Variable- Just fitting the ab dominal 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 CT Procedure of Abdomen and Pelvis 17

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: CT Procedure of Abdomen and Pelvis 18

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. CT Procedure of Abdomen and Pelvis 19

20. CT of Stomach CT Procedure of Abdomen and Pelvis 20 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. CT Procedure of Abdomen and Pelvis 21

22. Hepatic CT CT Procedure of Abdomen and Pelvis 22 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. CT Procedure of Abdomen and Pelvis 23

24. Biliary CT CT Procedure of Abdomen and Pelvis 24 Source: CT & MRI of The Whole Body - John R. Haaga, Fifth Edition

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

26. CT of Pancreas CT Procedure of Abdomen and Pelvis 26 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 CT Procedure of Abdomen and Pelvis 27 Source: CT & MRI of The Whole Body - John R. Haaga, Fifth Edition

28. CT of Pancreas CT Procedure of Abdomen and Pelvis 28 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. Arterial phase- 25 to 30 sec Venous phase- 55 to 60 sec Now we perform CT Enteroclysis/ Enterography for small intestine. CT Procedure of Abdomen and Pelvis 29

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. CT Procedure of Abdomen and Pelvis 30

31. CT Enterography In CT E nterography, 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. CT Procedure of Abdomen and Pelvis 31

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. CT Procedure of Abdomen and Pelvis 32 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. Arterial phase- 25 to 30 sec Venous phase- 55 to 60 sec Now we perform CT Colonography or virtual colonoscopy. CT Procedure of Abdomen and Pelvis 33

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 C olonography. Colonic distention: room air is used rather CO 2 because rapid absorption and painful. CT Procedure of Abdomen and Pelvis 34

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. CT Procedure of Abdomen and Pelvis 35 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 L 3 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 CT Procedure of Abdomen and Pelvis 36

37. CT for Adrenal Gland CT Procedure of Abdomen and Pelvis 37 Source: CT & MRI of The Whole Body - John R. Haaga, Fifth Edition

38. CT for Kidneys Area of scan from dome of diaphragm to S ymphysis 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 CT Procedure of Abdomen and Pelvis 38

39. CT for Kidneys CT Procedure of Abdomen and Pelvis 39 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 . CT Procedure of Abdomen and Pelvis 40

41. CT Urography CT Procedure of Abdomen and Pelvis 41 Source: CT & MRI of The Whole Body - John R. Haaga, Fifth Edition

42. CT Urography CT Procedure of Abdomen and Pelvis 42 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 CT Procedure of Abdomen and Pelvis 43

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. CT Procedure of Abdomen and Pelvis 44

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. CT Procedure of Abdomen and Pelvis 45

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. CT Procedure of Abdomen and Pelvis 46

47. Department Protocol Upper Abdomen Protocol CT Procedure of Abdomen and Pelvis 47 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 √ √ √ 7. Renal Donor √ Dual phase + CT Urography √ √ √

48. Department Protocol Lower Abdomen Protocol CT Procedure of Abdomen and Pelvis 48 S.N. Diagnosis Oral Contrast Rectal Contrast NCCT (5x5 mm) CECT (5x5 mm) Thin sections (3x3 mm) MPR (Sagittal + Coronal) 3D 1. Colonic pathology √ √ - √ √ √ - 2. Gynaecology pathology √ √ √ √ √ √ - 3. Pelvic tumor √ √ - √ √ √ -

49. Department Protocol CT Procedure of Abdomen and Pelvis 49 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). 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.   Unless specified, all films to be given as axial 5x5 mm along with Sagittal and coronal MPR Films for CT angiography: Axial, MPR & 3D Contrast Dose: Adult patient: 100 ml contrast with concentration of 300mg Iodine/ml. 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. CT Procedure of Abdomen and Pelvis 50

51. References !!! CT Procedure of Abdomen and Pelvis 51 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 ??? CT Procedure of Abdomen and Pelvis 52 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 !!!