Significant deterioration in clinical status, including abrupt decrease in hemoglobin or hematocrit, hypotension, tachycardia, tachypnea, abrupt change in fever curve, or increase in white blood cells. CT Abdomen and Pelvis The diagnosis of infected necrosis or fluid collection can be suspected clinically and may be confirmed by fine- needle aspiration for culture. Because aspiration introduces the risk of infection, CT abdomen and pelvis with IV contrast may be obtained when infection is suspected clinically to assess for the presence of gas within areas of necrosis or fluid collections; although, this is of limited utility for identifying early infection [29]. Extraluminal pancreatic enzymes in AP can damage adjacent blood vessels, resulting in vasculitis and pseudoaneurysm formation. An abrupt decrease in hemoglobin or hematocrit is suspicious for pseudoaneurysm rupture. Given speed of acquisition, CT abdomen and pelvis with IV contrast with both arterial and venous phase imaging is the preferred imaging modality for assessment of suspected pseudoaneurysm rupture. CT abdomen and pelvis without IV contrast may help in the detection of hemorrhage as high-density fluid without localization of an active source. Similarly, adding a noncontrast phase by performing CT abdomen and pelvis without and with IV contrast does not add additional diagnostic information. MRI Abdomen MRI is well suited for the follow-up of pancreatic collections; however, in most cases, fine-needle aspiration sampling and microbiological examination of the collection is necessary to definitively diagnose infection; although, this method is invasive and carries a risk of secondary infection. More recently, peripheral restricted diffusion on diffusion-weighted imaging and central low apparent diffusion coefficient has been demonstrated to identify the presence of infection within AP-associated collections with higher sensitivity and accuracy than gas bubbles on CT [29].
Acute Pancreatitis. Significant deterioration in clinical status, including abrupt decrease in hemoglobin or hematocrit, hypotension, tachycardia, tachypnea, abrupt change in fever curve, or increase in white blood cells. CT Abdomen and Pelvis The diagnosis of infected necrosis or fluid collection can be suspected clinically and may be confirmed by fine- needle aspiration for culture. Because aspiration introduces the risk of infection, CT abdomen and pelvis with IV contrast may be obtained when infection is suspected clinically to assess for the presence of gas within areas of necrosis or fluid collections; although, this is of limited utility for identifying early infection [29]. Extraluminal pancreatic enzymes in AP can damage adjacent blood vessels, resulting in vasculitis and pseudoaneurysm formation. An abrupt decrease in hemoglobin or hematocrit is suspicious for pseudoaneurysm rupture. Given speed of acquisition, CT abdomen and pelvis with IV contrast with both arterial and venous phase imaging is the preferred imaging modality for assessment of suspected pseudoaneurysm rupture. CT abdomen and pelvis without IV contrast may help in the detection of hemorrhage as high-density fluid without localization of an active source. Similarly, adding a noncontrast phase by performing CT abdomen and pelvis without and with IV contrast does not add additional diagnostic information. MRI Abdomen MRI is well suited for the follow-up of pancreatic collections; however, in most cases, fine-needle aspiration sampling and microbiological examination of the collection is necessary to definitively diagnose infection; although, this method is invasive and carries a risk of secondary infection. More recently, peripheral restricted diffusion on diffusion-weighted imaging and central low apparent diffusion coefficient has been demonstrated to identify the presence of infection within AP-associated collections with higher sensitivity and accuracy than gas bubbles on CT [29].