Peer-reviewed veterinary case report
In vivo radiographic characteristics associated with the mineral composition of calcium oxalate and struvite lower urinary tract uroliths in cats.
- Journal:
- Journal of veterinary internal medicine
- Year:
- 2026
- Authors:
- Pulido Vega, Diego et al.
- Affiliation:
- Service of Diagnostic Imaging · France
- Species:
- cat
Abstract
BACKGROUND: Radiography is widely used to diagnose lower urinary tract (LUT) urolithiasis in cats. Non-invasive identification of urolith mineral composition (UMC) is critical for therapy selection but remains challenging, as most data derive from dogs. HYPOTHESIS/OBJECTIVES: To describe in vivo radiographic features of feline calcium oxalate and struvite LUT uroliths and identify distinguishing characteristics. ANIMALS: Sixty-nine cats with LUT uroliths containing ≥70% of calcium oxalate (n = 45) or struvite (n = 24). METHODS: Retrospective cross-sectional study. Radiographs were evaluated for urolith size, shape, surface, internal architecture, subjective radiopacity, and quantitative radiopacity, assessed using a ratio of urolith-to-L5 vertebra pixel values (UOR). Diagnostic performance of urolith size and UOR was assessed with receiver operating characteristic (ROC) curves, calculating the area under the ROC curve (AUC). RESULTS: Struvite uroliths had lower quantitative radiopacity with a UOR cut-off ≤0.78 (AUC = 0.81, P < .001; sensitivity: 58%, specificity: 92%). They were larger, with a cut-off value of ≥7.3 mm (AUC = 0.75, P < .001; sensitivity: 38%, specificity: 98%), more frequently irregularly shaped, with rough surface and heterogeneous architecture. Urease-positive bacteriuria was present in 43% of struvite uroliths; infected struvite uroliths were significantly larger (median, 9.8 mm; interquartile range [IQR], 5.4-13 mm) than sterile ones (median, 4.6 mm; IQR, 2.6-5.4 mm; P = .02). Calcium oxalate uroliths were frequently smaller, more radiopaque, uniform, smooth, and associated with nephroliths. CONCLUSIONS AND CLINICAL IMPORTANCE: In vivo radiographic characteristics aid in differentiating struvite from calcium oxalate LUT uroliths, selecting non-invasive therapy, and reducing unnecessary surgeries.
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Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/41742498/