Radiol Clin N Am 40 (2002) 1229-1242.
Remer EM, Baker ME.
Chronic pancreatitis is a syndrome of destructive, inflammatory conditions arising from long-standing pancreatic injury [1]. Patients complain of chronic abdominal pain and may develop malabsorption from pancreatic insufficiency. In the most severe cases, diabetes mellitus results. Although etiological factors are many, alcohol is the most common cause in the United States population. Less common causes include chronic biliary tract disease, hereditary pancreatitis, cystic fibrosis, hyperlipidemia, hyperpara-thyroidism, and pancreas divisum [2]. Regardless of cause, the disease process leads to a final common pathway of irregular fibrosis, acinar loss, islet cell loss, and inflammatory infiltrates [1]. Thus, chronic pancreatitis may be defined as a continuing inflammatory disease, characterized by irreversible morphologic changes, that typically causes pain and/or permanent loss of function.
Although this definition may appear straightforward, the clinical diagnosis of chronic pancreatitis is often difficult. This is especially true in the early or mild stages of the disease. Unfortunately, histopatho-logy is almost never available. Random biopsies of the liver and kidney are commonly performed to diagnose diffuse diseases in these organs. Random pancreatic biopsy is rarely performed, however, due to a perceived risk of inciting acute pancreatitis or causing other complications, such as fistula or hemorrhage. The diagnosis of chronic pancreatitis is, therefore, based on a combination of clinical, functional, and morphologic features. Endoscopic retrograde pancreatography (ERP) and pancreatic function tests are the de facto gold standards, but are imperfect. Unfortunately, even these tests appear insensitive or discordant, with disagreement in 12% to 29% of cases [3,4].
In the past, diagnostic imaging has offered only insensitive means for making the diagnosis of chronic pancreatitis, usually detecting only advanced disease. Without noninvasive imaging techniques, early opportunities for therapeutic intervention may be missed. Recent advances in imaging techniques (as well as functional testing and molecular biology) and in the understanding of disease pathophysiology have offered the hope of earlier diagnosis and treatment. This article reviews the recognized findings of chronic pancreatitis on CT and ERP and then discusses more recently developed techniques including gadolinium-enhanced pancreatic MRI, MR cholan-giopancreatography (MRCP), and endoscopic ultrasound. Finally, variants of chronic pancreatitis and how to distinguish a pancreatic neoplasm from an inflammatory pancreatic mass are discussed.