99mTc-hexamethylpropylene amineoxime leukocyte scintigraphy in acute pancreatitis: an alternative to contrast-enhanced computed tomography?

Abstract

Contrast-enhanced computed tomography (CECT) is the most efficient imaging technique for the diagnosis and staging of acute pancreatitis (AP); its use, however, may be unfeasible in some patients as a consequence of the drawbacks of intravenous (IV) contrast material. The aim of this study was to test the utility of labeled leukocyte scintigraphy (LLS) as an alternative imaging technique to CECT for the staging of AP. Sixty-six patients with AP were prospectively studied. All patients underwent CECT and pancreatic LLS using (99m)Tc-hexamethylpropylene amineoxime as leukocyte label within a time interval of 2 days, in the early phase of AP. In addition, all patients had their serum C-reactive protein (CRP) concentration measured within 48-72 h after admission. CECT images were analyzed for Balthazar's grade of pancreatitis and for the presence or absence of pancreatic necrosis. Scintigraphic activity of 3-4 h planar images was scored on a 0-2 scale in relation to physiological liver uptake. LLS score was significantly related (p < 0.001) to both components of CECT (grade of pancreatitis and pancreatic necrosis). LLS and serum CRP showed similar results for detecting the most severe pancreatic damage as showed by their respective receiver operating characteristic (ROC) curves. Sensitivities and specificities of LLS score of 2 were, respectively, 62% and 96% for the detection of grade D-E pancreatitis and 90% and 89% for the detection of pancreatic necrosis. Scintigraphic score of 2 increased the likelihood of grade D-E pancreatitis from 32% (pretest probability) to 87% (posttest probability) (likelihood ratio: 13.9) and that of pancreatic necrosis from 16% to 60% (likelihood ratio: 8.4). Our results show that leukocytes are related to the severity of local pancreatic damage in AP. Thus, LLS is a potential alternative technique to CECT for staging AP.