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Studying the gall bladder.

SIR,-We were surprised to read Dr Henry C Irving's account of the demise of the oral cholecystogram' when, in fact, it appears to be undergoing a renaissance. In this centre and others engaged in the study of non-surgical management of gall stones the oral cholecystogram has been revived to assess gall bladder secretory function and cystic duct patency, as well as to characterise the stones. Minor calcification of gall stones-which can render a patient ineligible for any of the non-surgical treatmentsmay be apparent only on oral cholecystography. True, computed tomography can be used to assess stone density,2 but this is expensive. We find that the oral cholecystogram and ultrasound examination provide complementary information that is quite adequate to evalute patients for oral litholytic therapy (ursodeoxycholate), extracorporeal shockwave lithotripsy, and percutaneous solvent dissolution (with methyl tert-butyl ether) as well as cholecystectomy. Interesting work has been done to compare gall bladder emptying stimulated by fat and cholecystokinin using ultrasound,"4 and similar studies are under way for cholecystography. As is usually the case, local factors (such as staff and equipment) determine what works in an individual centre. A radiologist with skills and interest in gall bladder imaging can provide most of the information available from oral cholecystography, but such talents are not universally available. No one will deny Dr Irving the need for expert training of ultrasound radiologists. He is obviously concerned that amateurs with access to "soft money" are buying ultrasound scanners and trying to get into the act. The point is taken, but it begs another question: why not make formal training in