Abdominal Imaging - Dr. Hauck

TRAUMA PATIENTS
- CT if there is abdominal tenderness or a seatbelt sign     - Seatbelt sign- Not just abrasions!  They have bruising / ecchymoses.
     - With Seat Belt Sign, incidence of hollow viscus injuries (17%); splenic injuries (10%)
 
- Things that are easy to miss on CT scan 
     - Diaphragm injuries - think about in abdominal pain w/ dyspnea or chest pain
     - GI tract injuries - free fluid; bowel in discontinuity 
     - Pancreatic injuries - difficult to tell difference between contusion and ductal injury -
            - Important because these need intervention and waiting will be detrimental; 
            - ERCP or  MRCP - definitive diagnosis 

ABDOMINAL PAIN IN THE ELDERLY 
- Have a low threshold for imaging elderly patients with abdominal pain
      - Abdominal pain in elderly - 60-70% admitted; 30% with surgical process; 10% with return ED visits; 5% mortality 
      - Exam is not as reliable!!

- CT: diagnostic in 85% of people who had emergent surgical process
                 - Contrast?  IV/ PO/ both/ CTA?- if concerned about vascular - get CTA
                       > Contrast allergy - only true contraindication - airway compromise
                       > CIN - Cr rising >0.5 mg/dL or 25% from baseline; 
                       > Most elderly people have risk factors Cr > 1.5-2.0 
                       > Consider no contrast - if giving contrast -  HYDRATE 
                 - Metformin 
                       > Manufacture warning - no metformin 48 hrs before or after IV contrast;
                       > Increased risk - contraindications to metfomin, preexisting renal dysfunction 

BOWEL OBSTRUCTION
- Diagnosis 
     - Dilated loops of small bowel - diameter > 2.5 cm; 
     - >50% difference in caliber before and after transition

- Acute Obstruction Series X-rays - help if diagnostic; not so much if "normal" or "non-specific"
     - If an obstruction series is nondiagnostic and you suspect bowel obstruction, get a CT

     - PO contrast may add functional info, but often difficult to get into the patient... and not necessary.

- PO contrast is almost never needed in CT scanning


OTHERS
      - Diverticulitis - fat stranding; bowel wall thickening - CT with IV contrast best image

      - Appenditicits - senstivity 90% with no contrast; 100% with contrast 

      - Mesenteric ischemia - CT angio is the best 

      - Acute cholecystitis - cholesterol vs pigment stones can be seen on CT

                - Ultrasound is the first best test for suspected gallbladder pathology

      - Pancreatitis

                 - Generally don't need imaging.

                 - Consider imaging if changing clinical picture; not typical; no classic pancreatitis risk factors (to r/o malignancy)

---