It is time to think inside the (collimation) box; a quality improvement project to reduce over-scanning in CT scanning of the kidneys, ureters and bladder

OBJECTIVE: The Royal College of Radiologists (RCR) recommend CT of the kidneys, ureters and bladder (CTKUB) as the first-line investigation for renal colic, stating that excess scan length above the upper pole of the highest kidney should not exceed 10% of the total scan length. The project aim was to determine what proportion of CTKUB scans performed at a district general hospital (DGH) were meeting this standard and explore improvement options as necessary. METHODS: A retrospective study was performed on 100 consecutive patients who attended a Radiology Department with renal colic. The number of CTKUB slices above the upper pole of the highest kidney, relative to scan length, was recorded. The DGH radiographers believed over scanning could be reduced by viewing image acquisition in real-time and manually stopping the scan at the top of the highest kidney. This was implemented and a re-audit of 50 patients was performed. RESULTS: Scan length exceeded the standard on 81% of scans (81/100). Over scanning was reduced to 14% (7/50) post-intervention. CONCLUSION: This DGH was over scanning a large proportion of patients. Manually stopping the CTKUB significantly reduced over scanning. ADVANCES IN KNOWLEDGE: A small change to CTKUB scanning technique can significantly improve adherence to RCR guidelines.