Physical Address

304 North Cardinal St.
Dorchester Center, MA 02124

Diffuse Renal Parenchymal Diseases

Renal failure may be classified as prerenal when secondary to a reduction in the renal perfusion pressure gradient, renal when the result of intrinsic disease of the renal parenchyma, and postrenal when secondary to an abnormality of urine outflow. Prerenal renal failure may arise from alterations in renal artery perfusion or venous drainage. Renal artery stenosis results in decreased perfusion. Renal vein thrombosis results in increased…

Benign, Malignant, and Cystic Focal Renal Lesions

This chapter discusses benign and malignant renal lesions ( Box 63-1 ) with a separate note on cystic lesions based on the Bosniak classification. Box 63-1 Benign and Malignant Focal Renal Lesions Benign Lesions Simple renal cyst Oncocytoma Angiomyolipoma Leiomyoma Mesoblastic nephroma Adenoma Malignant Lesions Renal parenchymal tumors, including renal cell carcinoma subtypes Urothelial carcinoma Secondary renal tumors Lymphoma and leukemia Metastatic lesions Pediatric malignant tumors…

Imaging of the Kidneys and Urinary Tract

Anatomy Overview The Kidney The kidneys are paired retroperitoneal organs that primarily function in the excretion of metabolic waste. They are bean shaped with a convex lateral border and a concave medial surface known as the renal hilum. On intravenous contrast-enhanced studies, sequential enhancement of the renal vasculature, cortex, medulla, and collecting system occurs. In the early nephrographic phase, also called the corticomedullary phase, there is…

Lymph Node Imaging Techniques and Clinical Role

Lymph Node Imaging Techniques Imaging evaluation of lymph nodes forms an integral component of staging of various malignancies, including lymphomas, and is also helpful in the evaluation of certain infective and inflammatory processes within the abdomen. This has special relevance in the abdomen because the lymph node system in this region is not readily accessible for clinical examination or tissue sampling. Therefore, accurate identification and characterization…

Diffuse Splenic Lesions

Normal Variants and Congenital Anomalies The spleen begins to develop during the fifth week of embryogenesis when mesenchymal cells aggregate between the two leaves of the dorsal mesogastrium to form a lobulated embryonic spleen. Rotation of the stomach and growth of the dorsal mesogastrium translocate the spleen from the midline to the left side of the abdominal cavity. The left aspect of the mesogastrium fuses with…

Focal Splenic Lesions

Splenic Cysts Non-Neoplastic and Nonparasitic Splenic Cysts Etiology Non-neoplastic and nonparasitic splenic cysts are classified into primary (i.e., epithelial, true) and secondary (i.e., pseudocysts, false) cysts, depending on the presence or absence of the internal epithelial lining. Primary or epithelial cysts are considered congenital or developmental in origin. Trauma is the most likely etiologic factor of pseudocysts or secondary cysts, and other causes are considered to…

Gallbladder and Bile Duct Functional Imaging

Technical Aspects Functional imaging of the gallbladder and bile ducts is a valuable tool, providing critical information for the management of conditions of the biliary system. Modern functional techniques are noninvasive and can permit earlier and improved disease characterization resulting in appropriate and timely patient care. Ultrasonography is typically used as the initial modality for assessment of the biliary tree because it is fast, inexpensive, and…

Focal Gallbladder Wall Thickening

Focal gallbladder wall thickening is often an imaging diagnosis and encompasses a wide variety of differential diagnoses. Polypoid lesions of the gallbladder form an important group of conditions that are included in the differential diagnosis of focal gallbladder wall thickening and can be divided into neoplastic and non-neoplastic groups ( Figure 57-1 ). The neoplastic group includes adenomas, leiomyomas, neurofibromas, and gallbladder carcinoma. The non-neoplastic group…

Diffuse Gallbladder Wall Thickening

Diffuse gallbladder wall thickening is commonly encountered in diagnostic settings. The ability of ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI) to directly visualize the thickened gallbladder wall ascertains the importance of this condition. Ultrasound is the initial imaging technique for evaluation of suspected gallbladder disease. CT plays the role of a problem-solving tool in inconclusive ultrasound examinations, in staging of diseases, and as the…

Extrahepatic Bile Duct Tumors

Etiology The exact pathogenesis of bile duct carcinoma has not been described, but predisposing factors are similar to those causing intrahepatic bile duct neoplasms. It is believed that long-standing inflammation causes metaplasia and, finally, carcinogenesis. Prevalence and Epidemiology Tumors of the biliary tract constitute 2% of all cancers found at autopsy. The vast majority of bile duct tumors are extrahepatic (87% to 92%). Patients are typically…

Intrahepatic Bile Duct Tumors

Etiology The exact pathogenesis of bile duct carcinoma has not been described, but predisposing factors include long-standing inflammation, parasitic infestation, toxin and drug exposures, and genetic abnormalities. It is believed that repeated inflammation leads to chronic bile duct injury with formation of premalignant lesions. DNA alterations secondary to genetic mutations, bile salt exposure, or other carcinogens can predispose to biliary epithelial proliferation and subsequent tumorigenesis. Intrahepatic…

Tumors of the Gallbladder

Etiology The precise cause of gallbladder carcinoma is unknown, but cholelithiasis and pancreaticobiliary malformations are major risk factors. Gallstones and reflux of pancreaticobiliary enzymes are thought to result in chronic repetitive inflammation of the gallbladder mucosa that, over time, may undergo malignant transformation into invasive carcinoma. Prevalence and Epidemiology Gallbladder carcinoma is the most common primary biliary tract cancer and sixth most common gastrointestinal malignancy. It…

Dilated Bile Ducts

Etiology Biliary dilatation can occur as a result of biliary obstruction, from an altered functional state (e.g., after cholecystectomy or with sphincter of Oddi dysfunction), or uncommonly as a result of a choledochal cyst. The role of imaging is to identify a bile duct obstruction and define its level and cause. The cause may be intraluminal, mural, or extrinsic ( Figure 52-1 ). Cholangiographic and cross-sectional…

Diffuse Pancreatic Disease

General Considerations Diffuse involvement of the pancreas can occur with various inflammatory, infective, infiltrative, or neoplastic disorders. Any pathologic process that involves the pancreas focally also can cause diffuse involvement ( Box 51-1 ). More common causes of diffuse pancreatic involvement (e.g., pancreatitis) have been discussed previously. This chapter discusses infrequent causes and differential features. Box 51-1 Diffuse Pancreatic Diseases Inflammation Acute pancreatitis Chronic pancreatitis Chronic…

Miscellaneous Pancreatitis

Autoimmune Pancreatitis Etiology Autoimmune pancreatitis (AIP) is a peculiar form of chronic pancreatitis characterized by a fibroinflammatory process involving multiple organs with characteristic histopathologic and serologic features, association with other autoimmune disorders, and a propensity to respond to corticosteroid therapy (CST). Two subtypes of disease have recently been described: type I, also known as lymphoplasmacytic sclerosing pancreatitis, is considered a spectrum of immunoglobulin G4 (IgG4)-related systemic…

Imaging of Chronic Pancreatitis

Etiology Chronic pancreatitis is defined as an ongoing prolonged in­flammatory disease characterized by progressive irreversible structural changes resulting in permanent loss of endocrine and exocrine function. The Cambridge classification of 1983 acknowledged that chronic pancreatitis is typically associated with abdominal pain but occasionally can be painless and may recur. According to the revised pancreatic classification of pancreatitis from the Marseille symposium of 1984, acute and chronic…

Imaging of Acute Pancreatitis

Etiology Acute pancreatitis is an acute inflammatory disorder of the pancreas that has numerous causes ( Box 48-1 ). The most common risk factors are chronic alcohol consumption and choledocholithiasis. In 20% of cases no cause can be found. Box 48-1 Causes of Acute Pancreatitis Gallstones (45%) Alcohol (35%) Others (10%) Medications Hypercalcemia Hypertriglyceridemia Duct obstruction (e.g., tumor) Post–endoscopic retrograde cholangiopancreatography Hereditary Trauma Viral Post cardiac…

Cystic Lesions of the Pancreas

Etiology Cystic lesions of the pancreas encompass a wide spectrum of different pathologic entities, ranging from developmental, to inflammatory, to neoplastic cysts. Neoplastic cystic lesions, which are the most important, owing to their profound impact on patient prognosis and the frequent necessity of surgical treatment, are described in detail in this chapter. Although every pancreatic tumor may undergo central necrosis and manifests predominantly cystic, the term…

Solid Pancreatic Masses

Etiology The term solid pancreatic masses, in its wide meaning, encompasses neoplastic lesions and non-neoplastic masses, ranging from anatomic variants, such as pancreatic head lobulations, to focal inflammatory processes and neoplasms. This chapter will mainly discuss solid pancreatic neoplasms and provide differential diagnoses with other solid lesions, such as variants and focal inflammatory lesions, which are described in detail in other chapters. The cause of pancreatic…

Imaging of the Pancreas

Multidetector Computed Tomography Multidetector computed tomography (MDCT) has become a fundamental technique of pancreatic imaging. Today, higher image quality can be obtained in abdominal imaging, and this is even more significant in pancreatic imaging, in which the reduction of acquisition time, the possibility of multiple phases of enhancement imaging, and higher resolution images in all three spatial planes, with the possibility of excellent multiplanar image reconstructions,…