Is a CT scan of the chest with contrast contraindicated in a patient with a history of left nephrectomy (removal of the left kidney)?

CT Chest with Contrast in Patients with a History of Left Nephrectomy

A CT scan of the chest with contrast is not contraindicated in a patient with a history of left nephrectomy, provided the patient has adequate renal function in the remaining kidney. 1

Patient Evaluation Before Contrast Administration

When considering contrast-enhanced CT chest in a patient with a single kidney:

1. Assess renal function:

   • Check serum creatinine and estimated glomerular filtration rate (eGFR)
   • Review recent laboratory values for trends in renal function 1

2. Decision algorithm based on eGFR:

   • eGFR > 45 mL/min/1.73m²: Proceed with contrast-enhanced CT with proper hydration
   • eGFR 30-45 mL/min/1.73m²: Weigh risks vs. benefits and implement nephroprotective measures
   • eGFR < 30 mL/min/1.73m²: Consider non-contrast CT or alternative imaging; nephrology consultation may be needed 1

Preventive Measures to Reduce Risk

If contrast administration is deemed appropriate:

• Ensure adequate hydration before and after the procedure
• Use the minimum necessary dose of contrast
• Consider spacing out contrast studies if multiple are needed
• Avoid nephrotoxic medications 24-48 hours before and after contrast administration
• Monitor renal function 48-72 hours post-contrast 1

Clinical Considerations for Chest CT with Contrast

The American College of Radiology guidelines indicate that:

• For chest CT, IV contrast is optional but beneficial for detection and characterization of hilar lymph nodes
• Unlike abdominal CT, chest CT does not typically require both pre- and post-contrast phases 2
• In patients already receiving IV contrast for abdominal CT, chest CT should also be performed with contrast 2

Common Pitfalls to Avoid

• Failing to assess renal function before administering contrast
• Overlooking alternative imaging options when contraindicated
• Ignoring hydration status of the patient
• Disregarding medication interactions that may increase nephrotoxicity 1

Risk of Contrast-Induced Nephropathy (CIN)

The risk of CIN varies based on patient factors:

• Patients with normal renal function are at exceptionally low risk for CIN 3
• The incidence of CIN in outpatients undergoing contrast-enhanced CT has been reported at approximately 11%, with higher risk in those with pre-existing renal insufficiency 4
• In ICU settings, some studies have shown very low incidence (1.4%) of CIN with modern contrast agents and proper preventive measures 5

Remember that having a single kidney is not an absolute contraindication to contrast-enhanced CT chest. The decision should be based on the patient's current renal function, clinical necessity of the contrast study, and implementation of appropriate preventive measures to protect the remaining kidney function.