Access to computed tomography

Thomas et al's study into primary care access to computed tomography (CT) scanning1 (that found that the provision of open access CT for chronic headache reduced referrals to neurology by 88% in the scanned group) is a helpful addition to a sparsely researched area. Its premise and conclusion, however, ought not to be accepted without further consideration. The premise, that it is desirable to avoid referral to neurology, seems questionable as the aim must surely be to reach a diagnosis leading to treatment and, therefore, symptomatic improvement. A scan rarely did that. Of the 30 patients that had scans and were also referred to neurologists, 13 (43%) had a consultation that lead to the diagnosis of a treatable condition, mainly migraine.

A scan may have stopped 88% of referrals to neurology but did the patients feel better? CT in patients without clinical indicators may have provided short-term relief for doctor and patient, but in the absence of definite neurological indications the study demonstrates the risk: 10.2% had incidental abnormalities and in 5% the scan triggered the referral. Greater CT availability would surely lead to greater usage, more incidental abnormalities, and more referrals; while the average GP requested fewer than two CT scans, one GP requested seven.

GPs may refer fewer chronic headaches if open access CT is available. However, our patients would benefit more from an informed and skilled consultation (whether in primary or secondary care) leading to diagnosis and treatment, than from a scan leading to incidental findings or, more commonly, nothing.

• © British Journal of General Practice, 2010.