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The most common congenitally absent muscles are the pectoralis major and minor. Absence is usually incomplete. This anomaly is often one component of a syndrome associated with other hand (Poland syndrome) and thoracic anomalies. Computed tomography can identify partial absence of the pectoralis muscle and exactly define the altered anatomy. A patient with myasthenia gravis and isolated partial agenesis of the pectoralis muscle is presented.

In this chapter, three modalities--computed tomography, nuclear magnetic resonance imaging, and echocardiography--have been discussed. Each of these techniques offers unique advantages in the diagnosis of pericardial disease. Although echocardiography is the least expensive, most sensitive, and least invasive technique for the identification of pericardial effusion, false-positive and negative studies may be encountered. These are often resolved with the use of computed tomography and may be resolved with magnetic resonance imaging. Plain film radiography still has the advantage of identifying pericardial calcifications and will suggest the diagnosis of large pleural effusions at low cost and radiation dose. Exquisite portrayal of cross section anatomy using CT will aid in the diagnosis of multiple small tumor deposits and will clearly identify pericardial thickening. The value of magnetic resonance imaging awaits carefully controlled blinded studies, but its role in characterization of the content of pericardial effusions appears especially promising.

The radiographic diagnosis of Meckel's diverticulum in an asymptomatic individual is extremely difficult. Complications of the diverticulum may make preoperative diagnosis possible. A persistent, elongated filling defect within the distal ileum in a patient with chronic blood loss and symptoms of partial obstruction is most likely to be due to an inverted Meckel's diverticulum.

Medial displacement of the liver was observed in 35 cases of ascites using plain radiographs, total-body opacification, tomography, radionuclide imaging, peritoneography, and/or ultrasonography. In 16 cases the displaces liver was seen on plain radiographs. Separation of the liver and kidney was seen on ultrasonograms in every case; it was increased by addition of increments of fluid in patients undergoing peritoneal dialysis. Since the liver is surrounded by fluid, an interface between it and the extraperitoneal fat cannot account for the displacement seen on plain radiographs: rather, this is the result of a difference in density between liver and fluid.

A patient with a rare cystic hamartoma of the lung had diagnoses of tuberculosis, bronchiectasis, pneumonia, and neoplasm during the 23 years prior to resection of the lesion. The hamartoma had vascular elements which led to intermittent hemoptysis and, finally, to gross hemorrhage into the lung.

Transverse axial computed tomography (CT) has been combined with CT digital phlebography to study nine patients with superior vena cava syndrome. Six were due to malignancy, two were secondary to benign disease, and one was a paraneoplastic manifestation. This combined CT approach successfully identified the abnormal morphology of the superior vena cava, demonstrating external compression, encasement, or intraluminal thrombus in all patients and the collateral venous channels in eight. The efficacy and advantages of this technique are discussed. This technique is a rapid, informative, and cost-effective method for the workup of superior vena cava syndrome. The CT digital phlebogram, however, is not successful in regularly and optimally opacifying the normal superior vena cava because of the limited amount of contrast material, dilution effect of the nonopacified incoming flow from the jugular and azygos veins, and the lack of image enhancement from the CT digital scanograms.

The initial radiographs of 263 patients with pulmonary Mycobacterium kansasii infections were reviewed. Forty-nine untreated patients with active disease had unilateral lesions containing cavities less than 2 cm in diameter. The radiographs of these 49 patients were studied further and were found to have four distinct patterns: pattern 1, a circumscribed opacity containing a single cavity (39%); pattern 2, a circumscribed opacity with multiple lucencies (39%); pattern 3, multiple round or oval opacities containing lucencies (8%); and pattern 4, complex uncircumscribed opacity with lucencies (14%). Adjacent pleural thickening, "drainage area disease," and a "tail" sign were common. The initial radiographs of 27 untreated patients with solitary cavitary lesions less than 2 cm in diameter due to M. tuberculosis were studied for comparison. Only 22% had patterns 1-3 and generally showed more extensive adjacent parenchymal disease than cases with M. kansasii. A single circumscribed opacity containing one or more small cavities together with a "tail" sign, "drainage area disease," and little adjacent parenchymal disease is highly suggestive of M. kansasii infection. Since this infection usually requires more vigorous chemotherapy than tuberculosis, awareness of these findings has a practical implication.

Two patients with traumatic diaphragmatic defects visible on computed tomography are presented. The diagnosis was delayed for several years in both patients. The diagnosis of these acquired diaphragmatic defects is often difficult. Computed tomography can lead to earlier diagnosis by demonstrating the defect in some patients when radiographic studies are not diagnostic.

Three patients with idiopathic aneurysms of the superior vena cava, left innominate vein, and inferior vena cava are presented. The advantages of CT over other diagnostic modalities are discussed.

Computed tomography (CT) of the torso combined with simultaneous intravenous bolus injection of contrast media was used in sixteen patients suspected of having dissected their aorta. All patients had subsequent correlative percutaneous aortography within 24 h of the CT examination. Four patients proved to be normal, one had an aneurysm of the thoracic aorta, and eleven had aortic dissection (five type I, six type III dissection). All eleven patients with aortic dissections were diagnosed by CT and angiography; nine had spontaneous dissections and two had iatrogenic injuries to the aorta. Limitations of this imaging procedure include; inability to detect aortic valvular dysfunction and failure to provide an adequate perspective of aortic branch involvement. Potential benefits include: avoidance of aortogram in some cases, relative non-invasiveness, rapidity and ease of procedure, and less expense, radiation, contrast media, and discomfort to the patient. Early experience with CT-enhancement technique has reliably demonstrated normal as well as abnormal aortic wall morphology. It may have a place as an alternative to the conventional aortogram.

The postoperative chest radiographs of 173 patients who underwent median sternternal line. A total of 52 (30%) showed a thin lucent line one or more days after the operation. Clinical dehiscence developed in 4 patients, of whom 2 had a midsternal stripe and 2 did not. The authors feel that the presence of a sternal stripe is of little value in the radiographic diagnosis of sternal dehiscence.

The records of 65 consecutive patients discharged from the hospital with a diagnosis of primary parenchymal neoplasm of the kidney were reviewed. Four of the 65 patients had neoplasms which were not detected by excretory urography. The 4 undetected lesions included 3 renal cell carcinomas and 1 oncocytoma. All of these lesions projected from the anterior or posterior surface of the kidney, and all 4 were clearly demonstrated by computed tomography. Normal findings on an excretory urogram do not completely exclude a neoplasm of the kidney. When there is strong clinical suspicion of a renal neoplasm, computed tomography should be the initial examination or should be done even if the urogram has shown normal findings.

A 17-year-old boy had low back pain for four months prior to the development of sacral osteomyelitis, which led to the initial diagnosis of Crohn's disease. Musculoskeletal problems occur in about one-third of the patients with Crohn's disease. Only a few patients with osteomyelitis complicating Crohn's disease have been reported. This case is rare because he had had no gastrointestinal symptoms. This patient illustrates the point that musculoskeletal signs and symptoms, including osteomyelitis, may prove to be a manifestation of gastrointestinal tract disease.

The nephrogram is a sensitive indicator of renovascular compromise. An infrequently reported but characteristic nephrographic abnormality is the cortical rim nephrogram. This "rim sign" refers to a thin nephrographic rim outlining a kidney with an otherwise faint nephrogram. We report 2 patients with this nephrographic appearance due to acute renal artery insult. The rim nephrogram is a reliable sign of underperfusion of the kidney. It is dependent on collateral capsular vessels supplying the outer renal cortex. Underperfusion can be due to a primary renal artery problem or secondary to compromise of renal artery perfusion because of elevated interstitial or tubular pressure in the kidney. The sign has not been described with systemic circulatory problems.

Spontaneous subcapsular or perirenal hemorrhage is most often associated with a primary renal neoplasm which may be malignant or benign. No case of metastasis to the kidney causing such hemorrhage has been reported. The patient presented here had spontaneous perirenal hemorrhage due to metastasis to the kidney from a leiomyosarcoma of the uterus.

A case of bronchogenic cyst and two cases of pericardial cysts are presented. Our report illustrates the diagnostic utility of a pointed contour and the dependence of contour on position on CT in establishing the cystic nature of mediastinal mass.

673,000 hysterectomies were done in the United States in 1981. The mortality rate of 16.4/100,000 was less than that for appendectomy. Gynecologic surgery, however, is the most common surgical cause of complications related to the urinary tract with the reported incidence varying from less than 1 to 10%. We reviewed the charts of 1403 patients who had 736 abdominal, 315 vaginal and 143 radical or modified radical hysterectomies. Seventy (5%) patients had complications. Thirty-two (2.2%) patients had 35 complications related to the urinary tract. Complications directly related to surgery were grouped into ureteral injuries (13), fistulas (10), post surgical fluid collections (13), and hydronephrosis following radical hysterectomy. Characteristic images obtained by radiography, sonography (US), computed tomography (CT), and nuclear medicine (NM) are presented, and their use in each group of complications is summarized in the conclusion.

Identification of the retroperitoneal fascial planes with modern computed tomographic scanners allows for precise localization of pathologic processes in the individual compartments of the retroperitoneum. Metastatic disease to the posterior pararenal space or properitoneal space in 6 patients is reported. Two patients had diffuse histiocytic lymphoma and 4 had metastatic melanoma.

A concentric ring appearance of the cecal mucosa on a barium enema is a distinctive but nonspecific radiographic finding that has been termed the vortical, whirlwind, or coiled-spring sign. It can be caused by inversion of a postappendectomy stump and transient intussusception of the intact appendix in asymptomatic patients. The sign has also been reported with mucoceles, carcinoma, and endometriosis of the appendix, but there has been little mention of it in connection with acute appendicitis. The records of 18 patients with a coiled-spring sign and nonfilling of the appendix were reviewed. Acute appendicitis was proven in 14 of 18. In five of these 14, this sign was the only finding accompanying nonfilling of the appendix. On review of 53 cases of pathologically proven acute appendicitis studied by preoperative barium enema, 14 had a coiled-spring sign. The coiled-spring sign is nonspecific but can be produced by acute appendicitis, where it may be the only positive sign accompanying nonfilling of the appendix.

Chronic inflammatory bowel disease, diverticulitis, and appendicitis may be complicated by genitourinary tract problems. Patients with these diseases occasionally present with a genitourinary problem as an initial complaint prior to diagnosis of the underlying primary bowel disease. The correct diagnosis in these difficult cases will be arrived at sooner if the genitourinary manifestations of inflammatory diseases of the bowel are actively considered.

Traumatic longitudinal disruption of the carpus is a rare injury that usually occurs through a weak point between the third and fourth metacarpals and the capitate and hamate. Three cases are reported; all injuries were work related and occurred with a broad crushing injury to the hand and wrist. Two patients were treated by fasciotomies, a carpal tunnel release, and excision of a fractured hook of the hamate. The third patient was treated with carpal tunnel release and percutaneous pinning of a wide diastasis. Despite the return of wrist motion, pinch and grip strength remained below normal range in all three patients at follow-up examinations.

Multiple endocrine neoplasia syndrome IIB is an inherited autosomal dominant disorder with variable penetrance. Multiple organ systems are involved with a characteristic triad of medullary thyroid carcinoma, pheochromocytoma, and alimentary tract ganglioneuromas. Most patients have characteristic facies with patulous lips and thickened tarsal plates of the eyelids. The entire gastrointestinal tract can be involved from tongue to anus. Tongue nodules are common. Altered intestinal motility, dilation, diverticula, and mucosal abnormality may be seen radiographically. Gastrointestinal symptoms are common, may be the presenting manifestation of the syndrome early in life, and allow the radiologist to suggest the proper diagnosis. Five patients are described. All had megacolon.