II. Background
- Modern CT Scanners capture isotropic voxels (3 dimensional pixels)
- Voxels allows for software recompositing of imaging into any slice plane (e.g. coronal slices)
- Does not require specific instructions beyond overall imaging technique (e.g. IV contrast)
- Jaffe (2007) Radiology 242:175-81 [PubMed]
III. Indications: Acute Abdominal Pain (Oral water and IV Contrast unless otherwise noted)
- Appendicitis
- Diverticulitis
- Bowel Obstruction
- Acute Pancreatitis
- Ureterolithiasis or Nephrolithiasis (no contrast)
- Abdominal Aortic Aneurysm (IV contrast only)
- Mesenteric Ischemia
- Crohn's Disease (CT enterography)
- Abdominal Trauma (IV contrast only)
- Intraabdominal abscess (with Oral Contrast in addition to IV contrast)
IV. Technique: Oral Contrast
- Most Abdominal CT protocols require oral water only (no Oral Contrast)
- Patients with increased abdominal fat require less contrast
- Evaluation for Appendicitis or Diverticulitis does NOT require Oral Contrast
- Low Attenuation Contrast (air, water) is usually preferable to high attenuation Oral Contrast (e.g. barium, diatrizoate)
- High attenuation contrast may obscure malignancy and intestinal Hemorrhage
- Air alone is an excellent contrast due to low attenuation (-1000 Hounsfield Units)
- Allows for pneumoperitoneum (perforation) detection
- Oral water (400-600 ml) immediately prior to CT helps identify gastric lesions
- References
- Broder (2018) Crit Dec Emerg Med 32(6): 12-3
- High Attentuation Oral Contrast (Gastrografin/Gastroview, Omnipaque, Readi-Cat/Barium) Indications
- Patient indications for Oral Contrast
- Lean patient (e.g. BMI <19-20 kg/m2)
- Age <18 years old
- Condition indications for Oral Contrast
- Patient indications for Oral Contrast
- References
V. Technique: Intravenous Contrast
- Non-Contrast CT
- Clearly delineates intraabdominal anatomy and identifies abnormal lesions
- Preferred imaging when Ureteral Stone is suspected
- Ureteral Stones are also seen well on IV contrast imaging (but avoid Oral Contrast)
- Early Image Acquisition (Arterial Phase)
- Evaluates for arterial pathology (e.g. Aortic Dissection, Mesenteric Ischemia)
- Portal Venous Phase Imaging (Standard Timing)
- Standard CT imaging timing is the default protocol that identifies most pathology
- Delayed Image Acquisition (CT Urogram)
- References
- Broder (2022) Crit Dec Emerg Med 36(5): 20-1
VI. Adverse Effects: Children
- Sold-tumor risk from CT radiation exposure in children
- See CT-associated Radiation Exposure
- Girls: 1 new cancer per 300-390 CT Abdomen and Pelvis
- Boys: 1 new cancer per 670-760 CT Abdomen and Pelvis
- Miglioretti (2013) JAMA Pediatr 167(8): 700-7 [PubMed]
VII. References
- Ashoo, Orman and Hollander in Herbert (2015) EM:Rap 15(6): 17
Images: Related links to external sites (from Bing)
Related Studies
| Concepts | Diagnostic Procedure (T060) |
| ICD9 | 88.01 |
| ICD10 | 1962 , 56401-00 |
| SnomedCT | 169070004, 303670004, 146290008 |
| CPT | 74150, 1010526 |
| LNC | LA15396-7 |
| English | Computerized tomography of abdomen, CT of abdominal organs (procedure), Computed tomography of abdomen (procedure), Computed tomography of abdomen, CT of abdominal organs, CT of abdomen, CT scan of abdomen, abdominal CT scan, computed tomography of abdomen, computed tomography of abdomen (procedure), Computerised tomography of abdomen, ct abdomen scan, ct of abdomen, ct scan abdomen, abdomen ct, abdomen ct scanning, abdomen ct scans, cat scan abdomen, abdomen cat scan, abdomen ct scan, cat scan of abdomen, ct abdomen, CT scan abdomen, Computed tomography of abdominal organs (procedure), CT of abdomen (procedure), Computed tomography of abdominal organs, Computed tomography, abdomen, CT scan - abdominal, Computerized axial tomography of abdomen, C.A.T. scan of abdomen, CT scan;abdomen, CT scan of the abdomen |
| Spanish | tomografía computarizada de órganos abdominales, tomografía computarizada de órganos abdominales (procedimiento), TC de órganos abdominales, TAC de abdomen, TC de abdomen, tomografía computarizada de abdomen (procedimiento), tomografía computarizada de abdomen |
Ontology: CT of abdomen and pelvis (C1641132)
| Concepts | Diagnostic Procedure (T060) |
| ICD10 | 1963 , 56501-00 |
| SnomedCT | 419394006 |
| CPT | 74176, 74178, 1020544 |
| Spanish | TC de abdomen y pelvis, tomografía computarizada de abdomen y pelvis (procedimiento), tomografía computarizada de abdomen y pelvis |
| English | Computerised tomography of abdomen and pelvis, Computerized tomography of abdomen and pelvis, ct scan abdomen and pelvis (procedure), ct scan abdomen and pelvis, CT scan of abdomen and pelvis, Computed tomography, abdomen and pelvis, CT of abdomen and pelvis, Computed tomography of abdomen and pelvis (procedure), Computed tomography of abdomen and pelvis |
