Physical Address

304 North Cardinal St.
Dorchester Center, MA 02124

Abdominal Wall Hernias

Etiology Abdominal wall hernias, or external hernias (where abdominal contents protrude beyond the abdominal cavity), include inguinal, femoral, umbilical, incisional, spigelian, epigastric, lumbar, and obturator hernias. All abdominal wall hernias consist of a peritoneal sac that protrudes through a weakness or defect in the muscular layers of the abdomen. The defect may be congenital or acquired. Weakness of the transversalis fascia, which is the layer immediately…

Neoplastic and Non-neoplastic Conditions of the Abdominal Wall

Cross-sectional imaging modalities including ultrasonography, computed tomography (CT), and magnetic resonancy imaging (MRI) provide good anatomic detail of the abdominal wall and allow evaluation of pathologic processes in this area. Ultrasonography is frequently used as the first imaging modality to explore a palpable abdominal mass. Non-neoplastic Conditions Abdominal Wall InflamMation, Infection, and Fluid Collection Etiology Inflammatory processes involving the abdominal wall include diffuse edema ( Figure…

Non-neoplastic Conditions of the Peritoneum and Neoplastic Conditions of the Mesentery and Omentum

Non-neoplastic Conditions of the Peritoneum In many of the diseases discussed in this chapter the diagnosis is often initially raised on computed tomography (CT) or magnetic resonance imaging (MRI). However, in most cases, it is not possible to make a categorical diagnosis based on the imaging findings alone and it is necessary to correlate with clinical findings and laboratory tests. In this section we discuss peritoneal…

Peritoneal Fluid Collections, Peritonitis, and Peritoneal Abscess

Peritoneal Fluid Collections Etiology Ascites is the abnormal accumulation of fluid in the peritoneal cavity. There are numerous causes of ascites, including congenital, infective, inflammatory, and neoplastic diseases. In the United States the most common causes are liver disease and malignancy. In many parts of the world, tuberculosis is an important cause. The main causes of ascites and their frequency in the United States are listed…

Imaging of Disorders of the Male Urethra

Trauma Etiology Urethral trauma may result from blunt, penetrating, or iatrogenic injury. The spectrum of urethral injuries includes contusion, partial or complete disruption, and urethral injury and may involve either the anterior or posterior urethral segment. Blunt anterior urethral injuries are commonly associated with perineal straddle injury, whereas posterior urethral injuries are usually a consequence of the shearing forces involved with a pelvic fracture. Penetrating injuries,…

Imaging of Disorders of the Female Urethra

Urethral Diverticulum Etiology A urethral diverticulum is a focal outpouching of urethral tissue into the urethrovaginal space. It is thought to be due to postinflammatory dilatation and rupture of the periurethral glands (of Skene) into the urethra. Most urethral diverticula are acquired and occur in women between their third and sixth decades in age. The estimated prevalence of urethral diverticula is 0.6% to 6% of adult…

Benign and Malignant Testicular Lesions

Benign Testicular Lesions Etiology and Clinical Presentation Benign scrotal or testicular swellings and masses have many etiologies and different clinical presentations, as listed in Tables 78-1 and 78-2 . Of palpable nodules, 31% to 47% are benign at surgery. TABLE 78-1 Causes of Acute Scrotal Swelling Condition Symptoms Signs Comments Torsion Acute onset of severe pain, usually postpubertal Pain not relieved by scrotal elevation, high-riding testis,…

Imaging of the Scrotum

Technical Aspects Scrotal imaging has been one of the undeniable success stories of modern radiology. The scrotum is predominantly imaged for two clinical indications: the painless scrotal mass and the acute scrotum. Both conditions predominantly affect young men in the second through fourth decades of life. Rapid and accurate diagnosis is the goal of all imaging. Among several imaging modalities available, ultrasonography and magnetic resonance imaging…

Penile Trauma and Miscellaneous Penile Lesions

Etiology Penile lesions can be categorized by cause ( Box 76-1 ). Box 76-1 From Bhatt S, Kocakoc E, Rubens DJ, et al: Sonographic evaluation of penile trauma. J Ultrasound Med 2005; 24:993–1000. Penile Pathologic Processes Trauma Blunt trauma Penetrating or sharp trauma Acute bending accident Tumors Inflammation Infections Erectile dysfunction Impotence Priapism Postoperative penis Idiopathic Penile Trauma Penile fracture is usually caused by the exertion of…

Erectile Dysfunction

Etiology Erectile dysfunction manifests clinically most commonly as impotence and less commonly as priapism. The causes of impotence can be psychogenic, endocrinologic, neurogenic, anatomic, infectious, pharmacologic, or vasogenic. Vasogenic causes of erectile dysfunction include venous leak (aging, priapism, congenital, idiopathic) and arterial insufficiency (atherosclerosis, arterial stenosis or occlusion, perineal radiation, iatrogenic). Anatomic causes include phimosis and paraphimosis and fibrous plaques/scarring (from ischemia, Peyronie's disease, scleroderma, and…

Seminal Vesicle Lesions

Imaging Traditionally, the seminal vesicles were evaluated with seminal vesiculography. This has largely been replaced by computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound ( Figure 74-1 ). Computed Tomography The seminal vesicles are of soft tissue attenuation ( Figure 74-2 ). Cysts and small masses that do not deform the seminal vesicle are not well seen. Large masses or inflammatory change associated with infection…

Benign and Malignant Focal Prostate Lesions

Benign Focal Prostate Lesions Etiology Benign focal lesions of the prostate include benign prostatic hyperplasia (BPH) (see Chapter 72 ), congenital cysts, acquired cysts, prostatitis (acute bacterial, chronic bacterial, chronic pelvic pain syndrome [inflammatory and noninflammatory], and asymptomatic prostatitis), prostatic abscess, and prostatic calcification. The National Institutes of Health classification of prostatitis syndromes provides a useful conceptual framework. Categories I and II reflect acute and chronic…

Benign Prostatic Hyperplasia

Etiology Benign prostatic hyperplasia (BPH) is characterized by the increased volume of prostatic stroma and glandular epithelial cells involving the transitional zone and periurethral region of the prostate. Hormones such as androgens (testosterone and dihydrotestosterone [DHT]) and estrogens are thought to play a central role in proliferation of glandular epithelial elements. The neural, endocrine, and immune systems are also implicated in the prostatic tissue remodeling process.…

Adrenal Masses

Etiology Adrenal masses may be neoplastic, infectious, or hemorrhagic ( Box 71-1 ). Neoplasia is the most common cause for an adrenal mass seen on imaging. An incidentally detected adrenal mass as well as an adrenal mass in a patient with known malignancy elsewhere is most commonly due to a benign adenoma. Box 71-1 Causes of Adrenal Masses Benign Lesions Common Adenoma (lipid-rich) Adenoma (lipid-poor) Myelolipoma…

Enlarged Adrenal Glands

Recent technical advances in computed tomography (CT) and magnetic resonance imaging (MRI) have resulted in improved detection of subtle changes in adrenal gland morphology. The different morphologic patterns of adrenal gland enlargement on imaging can be classified as follows ( Figure 70-1 ): Diffuse enlargement Focal nodule or mass in a limb Multiple nodules in the gland Nodule with a smaller nodule within the nodule, the…

Urinary Tract Anomalies and Variants

Etiology Urinary tract anomalies encompass a wide range of abnormalities from the multiple varied components of the urinary tract—the renal parenchyma, the collecting system, the bladder, the urethra, and the vasculature. Anomalies result from alterations in the normal embryologic development of the urinary system. Detecting these anomalies requires an understanding of the embryologic development of the urinary system. Prevalence and Epidemiology Overall, it is estimated that…

Benign and Malignant Bladder Lesions

The urinary bladder is composed of the following four layers: 1. Urothelium: Transitional epithelium 2. Lamina propria: Vascular layer of connective tissue deep to the urothelium 3. Muscularis propria: Detrusor muscle 4. Adventitia: Connective tissue The bladder is an extraperitoneal organ with a serosal (peritoneal) covering present only over the dome. The remainder of the bladder is surrounded by perivesical fat. This chapter reviews the benign…

Benign and Malignant Ureteral Strictures

A ureteral stricture is a narrowing of the ureter that results in a functional obstruction. It may be the result of a variety of benign and malignant causes, which may be classified as intrinsic or extrinsic processes. The clinical presentation of patients with ureteral strictures depends on the cause of the stricture and the severity and duration of the associated obstruction. In acute ureteral obstruction, pain…

Urinary Tract Obstruction

Etiology Urinary tract obstruction (UTO) is a syndrome that may be caused by a wide range of pathologic processes. It may vary in the following: Degree: May be partial or complete. Site: May be unilateral or bilateral and may occur at any level of the urinary tract from the calyces to the urethral meatus. Duration: May be acute or chronic. Demographics: Common causes vary among prenatal,…

Renal Vascular Diseases

Renovascular Hypertension Etiology The most common cause of renovascular hypertension is renal artery stenosis, which may be caused by atherosclerosis (70% to 90%) or less commonly by fibromuscular dysplasia (10% to 30%). Rare causes of renal artery stenosis include arteritis, arterial dissection, and neurofibromatosis. Prevalence and Epidemiology Renovascular hypertension pertains to the causal relationship between renal artery stenosis and its clinical consequences, namely, hypertension and/or renal…