The utility of technetium 99m pertechnetate scintigraphy in the evaluation of patients with Meckel's diverticulum

The aim of this study was to assess the utility of technetium (Tc) 99m pertechnetate scintigraphy in the diagnostic workup of the pediatric patient with gastrointestinal (GI) bleeding and a suspected Meckel's diverticulum.

The charts of 235 consecutive patients evaluated with a Meckel's scan (n = 165) or with the discharge diagnosis of Meckel's diverticulum (n = 70) between January 1975 and October 1997 were reviewed for presenting symptoms, bleeding characteristics, diagnostic studies and pathological diagnosis. Those patients with lower GI bleeding and a serum hemoglobin level less than 11.0 g/dL who underwent a 99mTc pertechnetate scan (n = 43) were assessed for utility of the scan.

In all patients the Meckel's scan had a positive and negative predictive value of 0.93. However, in patients with lower GI bleeding and a hemoglobin less than 11.0 g/dL the Meckel's scan had a sensitivity of 0.60, a positive predictive value of 1.0, a specificity of 0.96, but only a negative predictive value of 0.74. As such, the probability that a child who presents with GI bleeding and a serum hemoglobin less than 11 g/dL will have a Meckel's diverticulum despite a negative Meckel's scan of 0.26. We further evaluated the eight patients with a false-negative scan: ectopic gastric mucosa was present on pathological examination in all eight patients. Pentagastrin stimulation was performed at the time of scintigraphic study in three of eight. Six of these eight patients had duplicate scans that also were negative. Patients with a false-negative (FN) scan had significantly increased hospital charges when compared with those with a true positive (TP) scan (TP = $5012 +/- 1992; FN = $8554 +/- 1506; P = .0001). Clinical suspicion had a major effect on the decision-making process in these patients independent of the results of the Meckel's scan, and all eight patients ultimately underwent exploratory laparoscopy-laparotomy with Meckel's diverticulectomy despite the scan results.

The relatively low negative predictive value of the Meckel's scan may result in the need for operative evaluation despite the scan data. As such, the contribution of the scan to clinical decision making is low. These findings suggest that exploratory laparotomy or laparoscopy may be indicated instead of scintigraphic scanning in the assessment of the anemic (hemoglobin less than 11 g/dL) pediatric patient with lower GI bleeding, especially in patients in whom a high suspicion for a bleeding Meckel's diverticulum exists.