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Ascites and Peritoneal Fluid Collections

Introduction Ascites is the pathologic accumulation of fluid in the peritoneal cavity. It is a common finding that can be associated with a large number of diseases. Imaging plays an important role in detecting and characterizing ascites. Although ascites may merely reflect generalized third-space fluid loss in conditions such as congestive heart failure, it is more commonly related to intra-abdominal factors that produce peritoneal fluid more…

Pathways of Abdominal and Pelvic Disease Spread

Traditionally, the abdominal cavity has been divided into a number of peritoneal, retroperitoneal, and extraperitoneal spaces. Although it is useful for learning abdominal anatomy and appreciating the confinement of disease in a particular space, this classic approach affords limited understanding of the intra-abdominal spread of disease. Dissemination of disease between the retroperitoneum and the peritoneal cavity, between the subdivisions of the retroperitoneum, and within the subperitoneal…

Splenic Trauma and Surgery

Splenic Trauma The spleen is the most commonly injured organ in blunt abdominal trauma. , It receives 5% of the cardiac output, accounts for 25% of the total reticuloendothelial cell mass, and plays a major role in clearing the plasma antigens. Recognition of this fundamental role in the immune response during the last century has led to greater efforts to preserve the spleen after injury. Nonoperative…

Benign and Malignant Lesions of the Spleen

Although it is affected by many diseases, the spleen is not considered a great challenge to the radiologist. In daily practice, the size and shape of the spleen typically are subjectively evaluated, and if there is no obvious splenomegaly or focal abnormality, the spleen usually is ignored. However, when abnormalities are detected, the radiologist plays an important role in providing a diagnosis and directing further clinical…

Pancreatic Trauma and Surgery

Pancreatic Trauma Traumatic injury to the pancreas is rare and difficult to diagnose. The retroperitoneal location of the pancreas is a mixed anatomic blessing in patients with abdominal trauma. Its fixed position anterior to the vertebral column provides excellent protection against deceleration injury and posterior stab wounds. This protected environment, however, can be breached by bullets and more severe deceleration forces that may cause life-threatening pancreatic…

Pancreatic Neoplasms

Introduction Benign, borderline, and malignant neoplasms can arise from exocrine, endocrine, intraductal, and stromal elements within the pancreas. Additionally, secondary (metastatic) neoplasms and non-neoplastic tumor-like conditions (e.g., mass-forming chronic pancreatitis) can occur. The World Health Organization (WHO) recognizes over 50 types of pancreatic neoplasms. However, only a few of these (adenocarcinoma, cystic neoplasms, pancreatic neuroendocrine tumors [PNETs], and metastases) are encountered with any frequency in clinical…

Pancreatitis

Pancreatitis is one of the most complex and clinically challenging of all abdominal disorders. It remains a major diagnostic challenge because its clinical manifestations are as protean as its causes. Indeed, only one in five severe cases of acute pancreatitis is recognized to be severe at initial presentation, and 42% of fatal cases of acute pancreatitis do not have a correct diagnosis before autopsy. Since the…

Hepatic Trauma and Surgery

Hepatic Trauma CLASSIFICATION OF HEPATIC TRAUMA The management of hepatic trauma patients has evolved significantly during the last three decades and is now based on well-defined treatment algorithms. This has highlighted the need for an accurate classification system as a basis for the clinical decision-making process. Fundamental to the development of these classification schemes and the subsequent treatment algorithms based on them is the widespread availability…

Vascular Disorders of the Liver and Splanchnic Circulation

The liver has a unique, dual blood supply in which 25% of the flow comes from the hepatic artery and 75% through the portal vein. There is an inverse relationship between these two blood supplies. If portal flow decreases, arterial flow will increase as if an impedance has been removed. In addition, there are several communications between these vessels that open in response to nervous and…

Diffuse Liver Disease

The liver has quite accurately been called the custodian of the milieu intérieur, and is vulnerable to a variety of metabolic, vascular, toxic, infectious, and neoplastic insults. Diffuse liver disease can be diagnostically challenging because of nonspecific and overlapping clinical signs and symptoms or even asymptomatic disease. The ability to assess liver and spleen size and the presence of ascites is limited on physical examination. Liver…

Focal Hepatic Infections

Technologic advances have significantly enhanced the role of radiology in the detection, characterization, and management of focal infectious diseases of the liver. Today, all cross-sectional techniques allow highly accurate detection of focal hepatic infections. Computed tomography (CT) is particularly helpful in revealing the presence of calcifications and gas and in detailing the enhancement pattern. With its multiplanar capacity and sensitivity to small differences in tissue composition,…

Malignant Tumors of the Liver

Primary malignant neoplasms of the liver are classified by the cell of origin ( Box 54.1 ). Secondary malignant liver tumors are metastases and lymphomas. Overall, metastases are the most frequent malignant tumors of the liver, except in patients with preexisting cirrhosis, in whom primary malignant neoplasms are more frequent. In this chapter, primary malignant liver tumors of hepatocyte origin are discussed first: hepatocellular carcinoma (HCC),…

Benign Tumors of the Liver

Hemangioma Hemangioma is the most common benign tumor of the liver, with a reported incidence ranging from 1% to 20% ( Table 53.1 ). , Hemangiomas occur primarily in women (female-to-male ratio of 5:1). Although hemangiomas may be present at all ages, they are seen more commonly in postmenopausal women. The worldwide prevalence of this tumor is fairly uniform. In a study of Vilgrain and colleagues,…

Postsurgical and Traumatic Lesions of the Biliary Tract

The two most common surgical procedures of the biliary tract likely to be encountered in day-to-day practice are laparoscopic cholecystectomy (LC) and biliary-enteric anastomosis. Specifically, given the high prevalence of cholelithiasis or gallstones in the United States, with roughly 20 to 25 million people affected, a large number of patients undergo cholecystectomy each year (~700,000). The revolutionary development and refinement of laparoscopic techniques during the last…

Inflammatory Disorders of the Biliary Tract

Primary Sclerosing Cholangitis EPIDEMIOLOGY AND CLINICAL FINDINGS Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease of unknown cause. This disease has a typical onset from 20 to 30 years of age but may begin in childhood; it has a 2:1 male-to-female predilection. PSC is commonly associated with inflammatory bowel disease, particularly ulcerative colitis. In patients with ulcerative colitis, 3% to 7.5% have or will…

Neoplasms of the Gallbladder and Biliary Tract

Biliary tract neoplasms include tumors in the bile ducts and gallbladder. Although they are infrequent, most neoplasms that arise from the gallbladder and bile ducts are malignant, resulting in poor prognosis. Gallbladder carcinoma is the seventh most common malignancy of the gastrointestinal tract and is the most common biliary malignancy; bile duct carcinoma occurs less often. Familiarity with the imaging characteristics of gallbladder and bile duct…

Cholelithiasis, Cholecystitis, Choledocholithiasis, and Hyperplastic Cholecystoses

This chapter reviews the imaging findings of gallbladder and biliary calculi and the role of computed tomography (CT), ultrasound, and magnetic imaging (MRI) in the assessment of these disorders. The chapter concludes with a discussion of the spectrum of noninflammatory gallbladder conditions referred to as the hyperplastic cholecystoses. Cholelithiasis Abdominal Radiography Only about 15% to 20% of gallstones are sufficiently calcified enough to be visualized on…

Magnetic Resonance Cholangiopancreatography

Since the first clinical application of magnetic resonance cholangiopancreatography (MRCP) in the early 1990s, MRCP has evolved from a technique with questionable potential for imaging of the biliary tract and pancreatic duct to one that is now recognized as a pivotal tool for the diagnosis of pancreaticobiliary disease. In fact, the evolution of MRCP has been such that at many centers, MRCP has replaced diagnostic endoscopic…

Postoperative Colon

Imaging studies such as water-soluble contrast enemas and computed tomography (CT) are often performed on the postoperative colon to exclude complications such as anastomotic leaks, strictures, fistulas, and abscesses. This chapter discusses the postoperative anatomy and major complications that occur after various forms of colonic surgery. Segmental Resection Segmental resection entails surgical removal of the diseased colonic segment, restoring bowel continuity with an end-to-end, end-to-side, or…

Miscellaneous Abnormalities of the Colon

Colonic Obstruction Mechanical large bowel obstruction is four to five times less common than small bowel obstruction and differs significantly in terms of cause ( Table 46.1 ), pathophysiology, therapy, and prognosis. Colon obstruction is most often the result of a neoplasm ( Table 46.2 ), whereas most small bowel obstructions are caused by adhesions. , A number of extracolonic disease processes, including gynecologic diseases, can…