Frequently used clinical scoring methods include the Ranson, Acute Physiology, Age, and Chronic Health Evaluation (APACHE)-II, Marshall, and the Bedside Index for Severity in AP (BISAP). Imaging is generally not necessary to document local complications in the early phase. This is because, even though pancreatic necrosis is a well-established risk factor for morbidity and mortality, the presence and extent of pancreatic and peripancreatic necrosis may not be reliably demonstrated on imaging before 5 to 7 days into the clinical course because both necrotic and edematous pancreatic parenchyma show heterogeneous enhancement. In addition, the extent of morphologic changes seen on imaging does not correlate well with the severity of organ failure [3]. Furthermore, even if imaging identifies the presence of fluid collections or pancreatic necrosis in the first week, typically no interventions for these complications are pursued in the early phase [3,18]. CT Abdomen and Pelvis Although it is generally not necessary to document local complications in the early phase with imaging, CT abdomen and pelvis with IV contrast is the primary imaging modality used in the assessment of a critically ill patient, particularly if cross-sectional imaging was not obtained earlier in the clinical course for AP diagnosis. CT abdomen and pelvis with IV contrast has shown consistent clinical value in predicting disease severity and outcomes in AP. The CT severity index is an imaging prognosticator based on the combined assessment of peripancreatic fluid collections and the degree of pancreatic necrosis. A higher CT severity index score is associated with increased morbidity and mortality. A modified CT severity index includes extrapancreatic complications (such as ascites) and vascular complications in the grading system. By including these additional factors, the modified CT severity index has a stronger correlation with patient outcome [2].
Acute Pancreatitis. Frequently used clinical scoring methods include the Ranson, Acute Physiology, Age, and Chronic Health Evaluation (APACHE)-II, Marshall, and the Bedside Index for Severity in AP (BISAP). Imaging is generally not necessary to document local complications in the early phase. This is because, even though pancreatic necrosis is a well-established risk factor for morbidity and mortality, the presence and extent of pancreatic and peripancreatic necrosis may not be reliably demonstrated on imaging before 5 to 7 days into the clinical course because both necrotic and edematous pancreatic parenchyma show heterogeneous enhancement. In addition, the extent of morphologic changes seen on imaging does not correlate well with the severity of organ failure [3]. Furthermore, even if imaging identifies the presence of fluid collections or pancreatic necrosis in the first week, typically no interventions for these complications are pursued in the early phase [3,18]. CT Abdomen and Pelvis Although it is generally not necessary to document local complications in the early phase with imaging, CT abdomen and pelvis with IV contrast is the primary imaging modality used in the assessment of a critically ill patient, particularly if cross-sectional imaging was not obtained earlier in the clinical course for AP diagnosis. CT abdomen and pelvis with IV contrast has shown consistent clinical value in predicting disease severity and outcomes in AP. The CT severity index is an imaging prognosticator based on the combined assessment of peripancreatic fluid collections and the degree of pancreatic necrosis. A higher CT severity index score is associated with increased morbidity and mortality. A modified CT severity index includes extrapancreatic complications (such as ascites) and vascular complications in the grading system. By including these additional factors, the modified CT severity index has a stronger correlation with patient outcome [2].