LABELED GRANULOCYTE SCANNING FOR THE DIAGNOSIS OF INFECTED NECROSIS IN ACUTE-PANCREATITIS - WHAT KIND OF LABELING SHOULD BE USED

Clinical and laboratory data or imaging results cannot provide a posit ive diagnosis of septic complications of pancreatic and peripancreatic necrosis in patients with acute pancreatitis. Confirmation can be obt ained only after percutaneous computed tomography (CT)-guided aspirati on of the necrotic tissues or fluid collection; although the important role of Tc-99(m)-HMPAO-labeled granulocyte scintigraphy has been rece ntly emphasized. The aim of this study was to determine the sensitivit y and specificity of 99m-technetium-hexa-methylpropyleneamine oxime (T c-99(m)-HMPAO)- or In-111-oxine-labeled granulocyte scintigraphy for t he diagnosis of infection in pancreatic or peripancreatic necrosis to define the ideal label for diagnosis. Thirty-six scintigraphic examina tions were performed in 34 consecutive patients (mean age, 58 +/- 2 ye ars) 20 +/- 2 days after the onset of acute pancreatitis (Balthazar cl asses A-C, n = 7; classes D and E, n = 29). The scintigraphic study in cluded scintigraphic tomography and static acquisition 1 and 3 h, resp ectively, after reinjection of the autologous Tc-99(m)-labeled granulo cytes and static images 3-4 and 24 h after the simultaneous reinjectio n of In-111-oxine-labeled autologous granulocytes. The diagnosis of in fected pancreatic or peripancreatic necrosis was confirmed with percut aneous CT-guided aspiration (14 positive aspirates among 20 performed) and sterile necrosis after negative aspiration (6 negative aspirates) or after a 6 +/- 1-month follow-up free of clinical or biological sig ns of ongoing sepsis. The sensitivity and specificity were 86 and 73%, respectively, for scintigraphic tomography, 100 and 55% for 3-h In-11 1 images, 93 and 68% for 3-4-h In-111 images, and 100 and 64% for 24-h In-111 images, The fall in splenic activity between the 3-4 and the 2 4-h In-111 images was 26 +/- 3% in patients with septic pancreatic and peripancreatic necrosis (n = 14) and 16 +/- 3% in those with sterile necrosis (n = 22) (p < 0.01). Labeled granulocyte scintigraphy was thu s shown to be an effective tool for the diagnosis of infection in panc reatic and/or peripancreatic necrosis due to acute pancreatitis, espec ially when the scintiscans are performed early after injection of Tc-9 9(m) or when the fall in splenic activity over the 24 h following rein jection of In-111 is measured in particularly difficult cases. These p romising preliminary results should be confirmed by a prospective stud y.