1. CT Contrast nephrotoxicity
-Cr elevation 25% or 0.5-1 within 72 hours
-Due to renal vascular effects, direct tox to tubular cells
-Third most common cause of hospital caused renal failure, after hypotension and surgery.
Tx with hydration: 100ml/hr at least 4 hrs before and 12 after.
-Mannitol/lasix/dopamine/others: disappointing.
2. Meformin interaction 
-Contrast competes with excretion of metformin
-Rare but 50% mortality from lactic acidosis,
-Manage by d/c metformin 48 hours after contrast. Check Cr before resuming.
-Metformin is often mixed with other drugs, be wary in diabetics.
3. Lung cancer patients undergoing treatment
-CT q3-6 months
-Include upper abd (liver, adrenals) bc mets are common
4. CT & mets
-Get a CT chest with colorectal, renal, sarcoma, melanoma
-Colorectal tends to have cavitary mets (septic emboli can also cause cavitary lesions)
-Renal/sarc/melanoma tends to have round solitary lesions.
5. Esophageal CA
-Poor for esophageal masses, endoscopy better
-Little serosa, spread common
-CT look at nodes/regional spread
6. GIST/sarcoma: liver mets look cystic with mural nodule.
7. Colorectal CA
-CT bad for finding primary lesion
-Hepatic mets (72% sensitivity in meta-analyses; newer CT scans ~low 90s)
8. Hepatocellular CA
-As the liver regenerates (after cirrhosis), and HCC develops it tends to prefer blood from hepatic artery instead of portal vein.
-Thus HCC will highlight brigher than liver in arterial phase.
-In delayed phase, washout of HCC relative to liver
-Enhancement + washout very characteristic of HCC.
9. SBO 
-CT is excellent for detection (>95% sensitivity), KUB ~70% sensitive
-Dilated loops proximally, collapsed loops distally
10. CT-interventions
-Drain large abscess: aspirate, leave in catheter
-Drain small abscess: aspirate
-RFA, cryoablation
-Biopsy.