Can a CT (Computed Tomography) scan of the abdomen and pelvis be performed in a patient with anuria (absence of urine production)?

CTA Abdomen and Pelvis in Anuria: Not Recommended

CTA abdomen and pelvis should not be performed in a patient with anuria due to the risk of nephrotoxicity from iodinated contrast and lack of clinical utility, with ultrasound being the appropriate first-line imaging modality instead. 1

Why CTA is Contraindicated in Anuria

Nephrotoxicity Risk

• Iodinated contrast agents used in CTA pose significant nephrotoxicity risk in patients with severe renal dysfunction, including those with anuria 1
• The American College of Radiology states that contrast-enhanced CTA is "very rarely indicated" in patients with renal failure given the potential nephrotoxicity 1
• The risk-benefit ratio must be carefully evaluated if CTA is necessary to diagnose vascular thrombosis or stenosis, and only the lowest dose of contrast needed should be used with adequate volume expansion 1

Lack of Clinical Role

• The American College of Radiology explicitly states there is no role for CTA in the initial evaluation of renal failure 1
• CTA provides no additional diagnostic benefit over safer alternatives in the evaluation of anuria 1

Appropriate Imaging Alternatives

First-Line: Ultrasound

• Ultrasound is the first-line imaging modality for patients with anuria or acute kidney injury 1
• Ultrasound can effectively evaluate for hydronephrosis, measure renal size, assess bladder distension and wall thickening, and detect stones without contrast exposure 1

Second-Line: Non-Contrast CT

• If ultrasound is not feasible or nondiagnostic due to body habitus, unenhanced CT abdomen and pelvis is the appropriate alternative 1
• Non-contrast CT is the most sensitive modality for urinary tract calculi and can characterize hydronephrosis by determining level and cause of obstruction 1
• CT can determine presence of hydronephrosis and measure renal size/volume without contrast administration 1

Third-Line: MRI/MRA

• Unenhanced MRI or MRA techniques may be considered when vascular pathology is suspected (such as renal artery stenosis, thrombosis, or arterial injury) 1
• Unenhanced MRA techniques have sensitivity of 73-100% and specificity of 82-99% for detecting >50% renal artery stenosis 1

Special Circumstance: Dialysis Patients

• Iodinated contrast may be administered to patients established on dialysis without residual renal function, as they have no remaining kidney function to protect 1
• However, even in dialysis patients, CT with IV contrast is not appropriate for the diagnosis and determination of the cause of kidney failure 1

Critical Pitfall to Avoid

Do not assume that because a patient is anuric they "have nothing left to lose" regarding kidney function. Anuria may be reversible (such as from bilateral ureteral obstruction), and contrast administration could prevent recovery of renal function or complicate management 2. The appropriate imaging pathway is ultrasound first, then non-contrast CT if needed 1.