As a foundation doctor, you’ll often be asked to ‘chase‘ a radiology report. You are not expected to write radiology reports, but you do need to know:
- Which scan to use.
- What key findings to look out for.
- When to escalate to seniors.
Common Presentations
- Flank pain > think stones (especially colicky).
- Haematuria > think stones, infection, malignancy.
- Sepsis > consider pyelonephritis or an obstructed infected system.
- Trauma > consider renal, ureteric, or bladder injury. [1]
Common Types of Scans
Bladder scan (bedside)
Used for assessing bladder volumes, post void residuals, acute urinary retention. [1]
Bladder scanner. Image from https://www.medikal.net/lb/urology-Produiten/urologesch-Apparater/Blase-Scanner/
US KUB
Useful for assessing obstruction/hydronephrosis/renal masses.[1]
Hydronephrosis on USS. Urine in dilated calyces appears black (hypoechoic). Image from Oxford Handbook of Urology (2016)
CT KUB (non-contrast)
Gold standard for suspected renal colic. [1]
Image showing CT KUB scan. Image from https://radiopaedia.org/cases/large-bowel-cecal-lymphoma-with-lymphomatosis?lang=us
CT Urogram (contrast)
Useful for detecting haematuria, suspected tumours, trauma. [1]
Image showing CT Urogram scan. Image from https://cairibu.urology.wisc.edu/wp-content/uploads/sites/1064/2021/12/Whittemore-Concurrent-1.pdf
Common Radiology Findings [1,2]
Renal / Ureteric Stones
- Appearance: Hyperdense (bright) focus within urinary tract ± hydronephrosis.
- Tip: Distinguish from vascular calcifications (follow course of ureters from kidney to bladder).
- Action:
- > Analgesia (Diclofenac suppositories if safe), fluids.
- > ± Tamsulosin for distal stones.
- > Antibiotics if infected.
- > Escalate urgently if obstruction + infection or deteriorating renal function
Hydronephrosis / Hydroureter
- Appearance: Dilated calyces, renal pelvis, or ureter proximal to obstruction.
- Action:
- > Check renal function and infection markers
- > Emergency if obstruction + infection or renal compromise → urgent decompression (stent or nephrostomy)
Perinephric Stranding
- Appearance: Streaky fat around kidney.
- Suggests: Infection (pyelonephritis) or obstructed infected stone.
- Action:
- > Check obs, bloods, urinalysis
- > Start antibiotics if sepsis suspected
- > Escalate to seniors (may need urgent intervention if obstruction present)
Renal Parenchyma Changes
- Findings:
- Loss of corticomedullary differentiation = pyelonephritis
- Wedge-shaped hypodensity = infarct / focal infection
- Masses (solid, cystic, complex)
- Action:
- > Treat infection if suspected.
- > Escalate any masses or suspicious lesions for senior review.
Bladder Findings
- Findings:
- Stones (hyperdense). Normally pass on own ones in bladder.
- Wall thickening (infection, malignancy, chronic obstruction)
- Filling defects (stone, clot, tumour)
- Air (recent catheter, fistula, emphysematous cystitis)
- Action:
- > Correlate with history (recent instrumentation vs pathology)
- > Escalate if focal thickening, filling defects, or unexplained gas.
Other Pathologies / Red Flags
- Perforation / urine leak: peri-renal / peri-ureteric fluid or extravasated contrast
- Trauma: lacerations, haematoma, devascularised renal tissue.
- Incidental findings: AAA, appendicitis, diverticulitis etc.
- Action:
- > Always escalate trauma, perforation, or leaks.
- > Don’t ignore incidental but important findings. Flag to seniors if unsure.
Key Tips for FY Doctors
- Always check patient identifiers, scan type, date before interpreting.
- Correlate imaging with history, bloods, urinalysis.
- Don’t just rely on reports – look at images yourself to learn.
- Escalate any obstruction that is infected or impairing renal function.
- Check eGFR & allergies before requesting contrast scans.
Summary
On call, the most important findings you need to recognise are stones, hydronephrosis, infection, trauma, suspicious filling defects and red flags). Escalate these promptly.
References
[1] Reynard, J., Brewster, S. and Biers, S. (2016a) Oxford Handbook of Urology. Oxford: Oxford University Press.
[2] Radiological investigation in acute renal colic (no date) Radiological investigation in acute renal colic | The Royal College of Radiologists. Available at: https://www.rcr.ac.uk/career-development/audit-quality-improvement/auditlive-radiology-templates/radiological-investigation-in-acute-renal-colic/ (Accessed: 10 October 2025).
Written by Pedro Silva (FY2)
Edited by Joseph Latham (CT3)
