Sodium pertechnetate Tc 99m antral scan in the diagnosis of retained gastric antrum.

Retained gastric antrum (RGA) is a major factor in recurrent peptic ulcer. We studied 121 patients with proven anastomotic ulcers following subtotal gastrectomy and Billroth II reconstruction with sodium pertechnetate Tc 99m to determine the presence of RGA. Of the patients, 59 required surgery, 22 had RGA, and 16 had a positive scan for RGA. This noninvasive examination has 100% specificity. If RGA is identified before operation, minimal time is wasted in exploration of the abdomen, which is especially important in dealing with emergency cases. When an antral scan is negative for RGA, the surgeon is still advised to search for this condition.