# Residual Intravenous Contrast Mimicking a Ureteral Stent on Noncontrast Computed Tomography in a Patient With Ureterolithiasis

## TL;DR

A patient's residual IV contrast from a prior scan was mistaken for a ureteral stent on a new CT scan, causing confusion until the correct diagnosis was made.

## Contribution

Highlights residual IV contrast as a diagnostic mimic of foreign bodies on CT scans in patients with recent contrast-enhanced imaging.

## Key findings

- Residual IV contrast was misinterpreted as a calcified ureteral stent on noncontrast CT.
- The patient's symptoms resolved after passing a ureteral calculus, confirming the correct diagnosis.
- Emphasizes the need for clinicians to consider residual contrast in patients with recent contrast-enhanced imaging.

## Abstract

This case describes a 53-year-old male patient presenting with right-sided abdominal pain and acute kidney injury (AKI) who retained intravenous (IV) contrast within the ureter from a previous image 24 hours prior at a different hospital that was initially mistaken for a calcified ureteral stent after presenting to a different hospital without the patient initially disclosing his previous hospital stay. This created diagnostic uncertainty and prompted subspecialty consultations for a device the patient had never received. The patient subsequently passed a ureteral calculus with resolution of symptoms and improvement in renal function. This case highlights the importance of recognizing residual IV contrast as a potential mimic of foreign bodies on computed tomography (CT), particularly in patients with recent contrast-enhanced studies.