CT Abdomen

 

CT Abdomen

 

Indications •

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1. Evaluation Evaluation of abdominal, flank, or pelvic pain, including evaluation of suspected or known urinary calculi and appendicitis . 2. Evaluation of renal and adrenal masses and of  urinary tract abnormalities with CT urography. 3. Evaluation of known or suspected abdominal or pelvic masses or fluid collections, including gynecological masses. 4. Evaluation of primary or metastatic malignancies, including lesion charact characterizat erization, ion, e.g., focal liver lesion. 5. Evaluation of diffuse liver disease (e.g., steatosis, steatosis, iron deposition disease, cirrhosis and biliary system, including CT cholangiography.

 

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6. Assessment for recurrence of tumors following surgical resection. 7. Detection of complications following abdominal and pelvic surgery, e.g., abscess, lymphocele, radiation change, and fistula/sinus tract formation . 8. Evaluation Evaluation of abdominal or pelvic inflammatory processes including inflammatory bowel disease, infectious bowel ,

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disease and its complications, without or with CT enterography . 9. Assessment of abnormalities of abdominal or pelvic vascular structures .

 

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10. Evaluation of abdominal or pelvic trauma. 11. Clarification of findings from other imaging studies or laboratory abnormalities. 12. Evaluation of known or suspected congenital abnormalities of abdominal or pelvic organs 13. Evaluation for small bowel or large bowel obstruction. 14. Screening for colonic polyps and cancers with CT colonography. 15. Guidance for interventional or therapeutic procedures within the abdomen or pelvis. 16. Treatment planning for radiation and chemotherapy and evaluation of tumor response to treatment, including perfusion studies. 17. Pre- and post-transplant assessment. 18. Noninvasive angiography of the aorta and its branches and noninvasive venography venography..

 

Liver Assess mass for hemangioma CT/MRI both good * CT/MRI both good R/O Mass (e.g. in hepatitis) CT typically used first in initial CT/MRI both good R/O Mets CT typically used first in initial CT/MRI both good workup; CT/MRI both good Pancreas Pancreatitis CT first Kidneys Assess cyst or mass CT first MRI for problem solving Workup of hematuria CT first (wo/w contrast) Renal artery stenosis MRA preferred Adrenal R/O nodule CT good * MRI good Spleen CT typically used first MRI for problem solving

 

Contraindications •

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For contrast exams, patients on glucophage/metformin. Must not take take medication on the day of the test. Additionally, the patient must stay off  these medications for 48 hours after the CT. Pregnancy. Allergy to contrast contrast material.

 

TYPES •

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WITH CONTRAST

WITHOUT CONTRAST : INDICATED ONLY IN CALCULI IN KIDNEYS AND URETERS, SEVERE CONTRAST ALLERGY.

 

CT ENTEROCLYSIS CONTRAST IS INJECTED THROUGH A CATETER

DIRECTLY INTO THE JEJUNUM 1000 ML OF CONTRAST IS GIVEN @ 75 ML PER MINUTE PREFERRED FOR DETECTING SMALL BOWEL PATHOLOGY, LIKE CROHNS DISEASE, STRICTURES, ABDOMINAL TB.

 

Routine Rou tine abdomen CT scan needs oral & iv contrast.

1- fasting 6-8 h 2- oral contrast 3-iv contrast

4- scanning

 

CONTRAST MATERIALS •

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Ionic monomeric contrast contrast material,eg amidotrizoate, iothalamate. Ionic dimeric contrast media, ioxaglate. Nonionic monomeric(low osmolar) contrast contrast media, iohex iohexol,iopentol,io ol,iopentol,ioxitol,iopamidol. xitol,iopamidol. Non ionic dimeric contrast (isosmolar), iotrolan, iodixanol

 

i.V i.Vupper arm. sv svcc Rt side of heart lung

left

side of heart body arteries portal

system liver  systemic venous excretion

of contrast via kidneys.

 

Three phases:

1-Arterial phase. 25 sec 2-Porto-venous phase. 40-60 sec 3-Delayed >2-5 min Routinly porto venous. Angio CT arterial

 

PROTOCOL Routine  abdomen & pelvis oral & iv contrast porto venous. Stone protocol abdomen pelvis without oral or iv contrast.

Liver protocol without + triple phases ( arterial , PV & delay delayed) ed)

 

LIMITATIONS •

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LESS SENSTIVE IN DETECTION OF GALL STONES. VERY LARGE AND OBESE PATIENT. LESS SENSTIVE IN SHOWING DETAILS OF BILLIARY TRACT

 

BASICS FOR INTERPRE INTERPRET TATION Substance

HU

Air

−1000 

Lung

−700 

Soft Tissue

+20 to +40

Fat

−84 

Water

0

CSF

10

Blood

+50 to +70

Muscle

+40

Bone

+700(cancellous +700(can cellous bone)to +3000 (dense bone)

 

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AIR APPEARS BLACK

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SOLID ORGANS APPEAR GREY

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BONES APPEAR WHITE WATER APPEARS BLACK

 

ACUTE PANCREATITIS