99mTc-HMPAO granulocyte scintigraphy in the early detection of postoperative asymptomatic recurrence in Crohn's disease

The usefulness of 99mTc-HMPAO scintigraphy in the early detection of postoperative recurrence of Crohn's disease was evaluated in 17 patients undergoing ileocecal resection and prospectively followed up for one year. Scintigraphy was performed 6 and 12 months after surgery and recurrence assessed by colonoscopy within two weeks. As controls, four patients with ileocecal resection for cecal carcinoma were studied. To perform scintigraphy, autologous granulocytes were labeled with 99mTc-HMPAO, injected, and tau-camera images acquired after 30 min and 3 hr. Six months after surgery, 4/8 Crohn's disease patients showed endoscopic recurrence, and 30-min scintigraphy was positive only in these four patients (four true positives, four true negatives). At 12 months, endoscopic recurrence was detected in 10/14 Crohn's disease patients, and 30-min scintigraphy was positive in 9/14 patients (eight true positives, three true negatives, two false negatives, one false positive). Scintigraphy at 3 hr showed a lower specificity in detecting CD recurrence both at 6 and 12 months. The endoscopic and 30-min scintigraphic score were significantly correlated both at 6 and 12 months (P = 0.007; P = 0.04). Scintigraphy was negative in 4/4 controls at 30 min (four true negatives) and positive in 1/4 (one false positive) at 3 hr. We conclude that 99mTc-HMPAO scintigraphy at 30 min is a sensitive technique for the early detection of Crohn's disease recurrence in patients under regular follow-up after surgery.