THE arrival of the scanner at Blackburn Infirmary (LET, May 18) has brought joy to many East Lancashire doctors who have fought and stood behind Blackburn Trust to introduce magnetic resonance imaging into Blackburn.

This is the most powerful diagnostic tool in the world and with the advent of new software and hardware it will take a long time to replace this apparatus.

MRI is more sophisticated than CT scanning, allowing more accurate differentiation of abnormal from normal soft tissue.

There are limits to its use. Patients with cochlear implants and intracranial aneurysm clips, intraocular foreign bodies are not allowed for scanning. Cardiac pacemakers can malfunction in the magnetic field.

Scanning usually takes an average of 30 minutes and it is usually noisy.

What can the mri do for us? It has a multitude of uses, including examining and detecting spinal compression, cancer of the cervix, confusional states, brain and kidney tumours, football injuries, cancer of the breast and pancreas, multiple sclerosis, sciatica, liver tumours and Aids.

So what are the drawbacks? First the cost - in the private sector, one single scan can cost about £500 - and the noise and claustrophobia. Up to five per cent of patients suffer claustrophobia in the scanner.

So what is the future? I can only say that it is very bright and very encouraging indeed. There are still many new uses for MRI which are still being found.

DR F K B APALOO, Montague Health Centre, Blackburn.

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