A simple KUB radiograph should not be the initial investigation for ureteric colic when non-contrast CT is available, a UK study has asserted.

A simple KUB radiograph should not be the initial investigation for ureteric colic when non-contrast CT (NCCT) is available, a UK study has asserted [1].

NCCT has been hailed to be both more sensitive and more specific than IVU for detecting ureteric calculi, and more cost-effective. The proportion of accident and emergency departments in the UK using NCCT rather than IVU to investigate ureteric colic is thought to be rising.

A group of radiologists at St James University hospital in Leeds, where NCCT is used to investigate colic, retrospectively reviewed all imaging tests for 120 patients admitted with a history consistent with colic and hematuria.

Three-quarters of the patient group had a KUB radiograph prior to NCCT, and 50.8 per cent had calculi on NCCT. Patient management was the same whether or not they had undergone a KUB radiograph.

On reviewing these findings, a multidisciplinary team recommended that KUB radiographs should not be routinely requested before NCCT.

Following the recommendation, the research group prospectively assessed 116 patients with the same inclusion criteria. They found preliminary KUB radiographs were carried out in just six per cent; as with the previous group, all patients underwent NCCT, and a similar proportion were diagnosed with calculi on NCCT, 51.7 per cent.

The group said: "NCCT should be the initial imaging examination for acute ureteric colic. Up to 50 per cent of patients with clinical suspicion do not have stone disease, and therefore, preliminary KUB radiographs with attendant radiation and cost implications are unjustified."

The researchers concluded: "The KUB radiograph can be omitted in the initial investigation of suspected acute ureteric colic when NCCT is available. However, it still has an important role as an imaging follow-up for NCCT-proven radio-opaque stone disease."

[1] Is the KUB radiograph redundant for investigating acute ureteric colic in the non-contrast enhanced computed tomography era?
Clin Radiol 2008; Articles in Press