Perfusion Computerized Tomography Can Predict Pancreatic Necrosis in Early Stages of Severe Acute Pancreatitis  Yoshihisa Tsuji, Hiroshi Yamamoto, Shujiro Yazumi, Yuji Watanabe, Kazuhiro Matsueda, Hiroyuki Yamamoto, Tsutomu Chiba  Clinical Gastroenterology and Hepatology  Volume 5, Issue 12, Pages 1484-1492 (December 2007) DOI: 10.1016/j.cgh.2007.07.014 Copyright © 2007 AGA Institute Terms and Conditions

Figure 1 Perfusion CT images taken immediately after the onset of SAP. The perfusion CT was performed after a bolus injection of 40 mL of iodixanol at a rate of 4 mL/s. The consecutive images of the four 8-mm–thick sections were obtained every second for 48 seconds. (A–D) The time series after a bolus injection into the same section in a representative patient (Table 1, patient 3). (A) The image before the injection of contrast material; (B) the image at 8 seconds after the bolus injection; and (C and D) the image at 16 and 24 seconds after the injection, respectively. Clinical Gastroenterology and Hepatology 2007 5, 1484-1492DOI: (10.1016/j.cgh.2007.07.014) Copyright © 2007 AGA Institute Terms and Conditions

Figure 2 Deconvolution of the perfusion CT images by comparing the shape and height of the time-density curve of each pixel. By using the aorta as the input artery and the portal vein as the output vein, PBF (mL/100 g/min) and PBV (mL/100 g) were calculated by using Toshiba box-MTF software as follows. (A) ROIs were selected at the aorta (1), portal vein (2), and the pancreatic body (3). (B) The changing density of each ROI was calculated (in Hounsfield units), and the time-density curve of each ROI was plotted. Clinical Gastroenterology and Hepatology 2007 5, 1484-1492DOI: (10.1016/j.cgh.2007.07.014) Copyright © 2007 AGA Institute Terms and Conditions

Figure 3 Perfusion CT images of the pancreas of a healthy 32-year-old male control subject. (A) Contrast-enhanced CT image of the pancreas. (B) PBF (mL/100 g/min). (C) PBV (mL/100 g). The color scale is shown as a bar on the left edge of the perfusion images (B and C). The white areas in the perfusion images indicate the fast blood flow or high blood volume, and the purple areas indicate slow blood flow or low blood volume. The pancreas hemodynamics revealed faster blood flow and a higher blood volume than found in the liver. Clinical Gastroenterology and Hepatology 2007 5, 1484-1492DOI: (10.1016/j.cgh.2007.07.014) Copyright © 2007 AGA Institute Terms and Conditions

Figure 4 Comparison of PBF with HBF values and of PBV with HBV values calculated with perfusion CT to detect pancreatic ischemia. In (A and D) 5 healthy control subjects and in (B and E) 21 patients with AEP, the PBF was significantly faster than the HBF, and the PBV was significantly greater than the HBV. (B and E, open circle) Only 1 (Table 1, patient 10) of 21 patients with AEP was found to have pancreatic ischemia by perfusion CT. (C and F) All of the 9 subjects with ANP were found to have pancreatic ischemia by perfusion CT. Clinical Gastroenterology and Hepatology 2007 5, 1484-1492DOI: (10.1016/j.cgh.2007.07.014) Copyright © 2007 AGA Institute Terms and Conditions

Figure 5 Perfusion CT of representative patients. (A) Dynamic CT showed grade C pancreatitis in patient 7 (Table 1). The density of the pancreas was increased to 47 Hounsfield units and ANP was ruled out. (B and C) Perfusion CT showed that the (B, arrowheads) PBF was slower than the (B, arrows) HBF and that the (C, arrowheads) PBV was less than the (C, arrows) HBV, indicating pancreatic ischemia. (D) Pancreatic necrosis detected by contrast-enhanced CT 3 weeks later. (E) Dynamic CT also showed grade C pancreatitis in patient 28 (Table 1). The density of the pancreas was high, and AEP was diagnosed. (F and G) Similar to patient 7, perfusion CT showed that PBF and PBV were faster and more than HBF and HBF, respectively. (H) However, no evidence of pancreatic necrosis was disclosed by contrast-enhanced CT 3 weeks later in this patient. Clinical Gastroenterology and Hepatology 2007 5, 1484-1492DOI: (10.1016/j.cgh.2007.07.014) Copyright © 2007 AGA Institute Terms and Conditions

Figure 6 A case of pancreatic necrosis predicted by perfusion CT. The patient (patient 9; female, 87 y) died from systemic infection at day 22 (Table 1). (A) Dynamic CT performed at day 1 showed grade E pancreatitis. The density of the pancreas was increased to 42 Hounsfield units and ANP was ruled out. (B and C) Perfusion CT was performed at day 1, showing that the (B, arrow) PBF was slower than the HBF and that the (C, arrow) PBV was less than the HBV, indicating pancreatic ischemia. (D) Autopsy findings at day 22 showed pancreatic necrosis, the position of which corresponded to that of pancreatic ischemia detected by perfusion CT (arrow). Clinical Gastroenterology and Hepatology 2007 5, 1484-1492DOI: (10.1016/j.cgh.2007.07.014) Copyright © 2007 AGA Institute Terms and Conditions