Biomedical subjects
Publications and source records attributed to M S Shin.
Computed tomographic (CT) findings of a rare case of triple-barreled aortic dissection was described. CT demonstrated the extent of dissection, a communication between two channels, and three lumens separated by the intimal flap and a thin undetached tunica media, resembling a Mercedes-Benz mark.
The CT appearance of dilated hepatic lymphatics in liver transplant recipients has been described recently. We have observed similar findings of presumed hepatic lymphatic dilatation and perivascular lymphedema in 20 patients seen over an 8-month period, none of whom had received a liver transplant. Review of these patients' records showed that 18 (90%) of 20 had underlying disease processes that could have caused dilated lymphatics as a result of either increased lymph flow or lymphatic obstruction. We have grouped these processes into three etiologic categories: (1) posttraumatic hepatic lymphatic obstruction, (2) obstruction caused by malignant lymphadenopathy, and (3) congestive hepatomegaly caused by cardiac decompensation. The appearance of hepatic lymphatic dilatation and surrounding lymphedema needs to be recognized so that lymphatic dilatation is not mistaken for dilated intrahepatic bile ducts.
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There can be many diagnostic pitfalls in the evaluation of the aortopulmonary window by chest radiography alone. Large masses that are easily identified on computed tomography may be essentially undetectable; also the appearances of aortopulmonary window lesions on conventional radiographs are frequently nonspecific, or may even be misleading. Careful evaluation of this region of the mediastinum is important because the aortopulmonary window is commonly the site of adenopathy secondary to neoplastic and inflammatory diseases, as well as vascular pathology. After review of the normal anatomy of the aortopulmonary window, seven selected cases are presented that demonstrate the importance of computed tomography in arriving at the correct diagnosis when conventional chest radiographs are nonspecific or equivocal.
Two cases of nonobstructive or pseudocoarctation of aorta evaluated by computed tomography are presented. Clinical features along with chest radiography and computed tomography findings provided specific information, making further workup by catheterization and angiography unnecessary. As most cases of nonobstructive coarctation are asymptomatic and require no treatment, its recognition is of great practical importance.
Numerous reports of complications of central venous catheters have appeared in the literature. Most often these complications are diagnosed by plain or interventional radiography. Two cases are reported in which computed tomography was instrumental in diagnosing an abnormality that was not obvious on conventional radiography. This report demonstrates the value of this noninvasive technique for rapid and accurate evaluation.
Computed tomography and magnetic resonance imaging of a malignant hemangiopericytoma in a 58-year-old woman are described. The tumor was initially found in the abdomen and resected 34 years ago, but recurred 18 years later, followed by repeated recurrence and eventually metastasis to the lung and then to the liver. The lung nodules were round or oval, homogeneous, and well circumscribed while the massive tumor in the right lobe of the liver was poorly delineated with irregular areas of cystic necrosis. With proper setting of the repetition time and echo delay, the metastatic tumor became distinct from the uninvolved hepatic tissue on magnetic resonance imaging. In this case computed tomography and magnetic resonance imaging were complementary in evaluation of such a tumor.
Heterotopic heart transplantation can be performed in the presence of high pulmonary vascular resistance. The authors call attention to a rare, but potentially life-saving procedure.
We describe 6 patients with chronic interstitial lung disease in whom open lung biopsies showed respiratory bronchiolitis. The patients ranged from 28 to 46 yr of age (mean, 36 yr) and included 5 men and 1 woman. All were heavy cigarette smokers. Five had respiratory symptoms, most commonly cough and dyspnea. Diffuse interstitial infiltrates were seen on chest radiographs in 5 and bibasilar atelectasis in 1. Pulmonary function tests showed mild to moderate restriction in 4 and decreased diffusing capacity in 4. The initial pathologic interpretation in 3 patients suggested a variant of idiopathic pulmonary fibrosis, and these patients received corticosteroids because of this diagnosis. All patients have remained stable or improved after a mean follow-up of 3.2 yr. Respiratory bronchiolitis should be recognized as an uncommon cause of chronic interstitial lung disease. It must be separated from the other diseases in this category because of marked differences in treatment and prognosis.
Two cases of asymptomatic Bochdalek hernia in adults with identical roentgenographic findings are reported. Computed tomography (CT) in each case revealed a round mass with a low attenuation coefficient identical to that of adipose tissue, abutting the thoracic surface of the diaphragm and connecting with the subdiaphragmatic density through a diaphragmatic defect. A case of diaphragmatic lipoma was also presented for demonstration of the CT differentiation between lipoma and hernia of the diaphragm. The CT findings for a Bochdalek hernia are characteristic enough for making a definite diagnosis and render other diagnostic modalities unnecessary.
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Two cases of inflammatory pseudotumors of the lung are reported and the literature is reviewed. The lesions are commonly discovered incidently in asymptomatic young persons and are characterized by a solitary, homogeneous, well-circumscribed mass composed of the major kinds of inflammatory elements in various proportions. The lesion should be differentiated from true neoplasms and common granulomas. Resection of the lesion results in permanent cure.
Computed tomography characteristics of two primary sternal neoplasms (plasmacytoma and chondrosarcoma) and one metastatic tumor (malignant melanoma) are described. These cases demonstrate that computed tomography is much superior to the conventional radiography in the evaluation of sternal neoplasms. Biopsy, however, remains essential for confirmation of the nature of the tumor.
Two rare cases of cystic lesions with spontaneous radiographic resolution are presented. One is a 21-year-old man with a mediastinal seminoma containing a cystic lesion within the neoplasm that disappeared spontaneously on subsequent chest radiography and computed tomography. Another is a 65-year-old man with a pericardial cyst that also disappeared in subsequent chest radiography. The possible mechanisms for such rare occurrences are discussed.
Four cases of tracheoesophageal fistula evaluated by computed tomography are presented. In addition to demonstrating the site of fistula, computed tomography was helpful in suggesting etiology and detecting pulmonary and mediastinal complications. Due to its ease of performance in critically ill patients and its unequivocal display of anatomy, we believe computed tomography should be the recommended diagnostic modality for tracheoesophageal fistula.
The clinical, radiographic, and pathologic features were studied in 24 cases of bronchiolitis obliterans and 16 cases of usual interstitial pneumonia, to define better their distinguishing characteristics. Bronchiolitis obliterans had a more acute onset often associated with fever, while the presentation of usual interstitial pneumonia was insidious with dyspnea and cough. The radiographs in usual interstitial pneumonia uniformly showed bilateral interstitial opacities, while they were more variable in bronchiolitis obliterans, with air space densities in 15 and interstitial opacities in nine. Prognosis was considerably better for bronchiolitis obliterans patients. Resolution of disease occurred in nearly half, while no patient with usual interstitial pneumonia recovered. Three individuals with bronchiolitis obliterans (12.5%) died of progressive disease, compared to 10 with usual interstitial pneumonia (62.5%). Pathologically, the lesion in bronchiolitis obliterans affected mainly air spaces in a peribronchiolar distribution, while the changes in usual interstitial pneumonia were mainly interstitial and randomly distributed. The fibrosis in bronchiolitis obliterans was composed of proliferating fibroblasts, compared to collagen deposition in usual interstitial pneumonia. These findings emphasize that bronchiolitis obliterans and usual interstitial pneumonia represent separate and distinct clinicopathologic entities.
We have reported a typical case of extra-adrenal pheochromocytoma. The tumor, located in the posterior mediastinum was diagnosed five years after onset of classic symptoms and signs. Our case illustrated the usefulness of computerized tomography in locating pheochromocytomas. A high index of suspicion is required to detect such a unique tumor and avoid unnecessary delays in diagnosis and treatment.
A retrospective morphologic study of 80 cases was undertaken to determine factors affecting detectability of computed tomographically (CT) proved aortopulmonary (AP) window lesions on conventional posteroanterior (PA) and lateral chest radiographs. Criteria used for determining abnormality were: solitary lymph node enlargement over 1.5 cm or three or more 1-cm nodes and obvious large masses or vascular anomalies. CT scans and corresponding PA and lateral radiographs were analyzed for lesion detectability, size, and location. In 49% of cases there was no detectable lesion in the AP window on radiographs; a definite AP window lesion was seen in 41%, and 10% were equivocal. Major contributing factors to low detectability of AP window lesions on radiographs include size and, more important, location of the lesion. An additional 45 cases of CT-proved normal AP windows were retrospectively reviewed to determine the false-positive rate of PA and lateral radiographs in detection of AP window lesions: 43 (96%) were classified as negative, the remaining two (4%) as equivocal. Although the AP window is a small space, it is the site of many pathologic conditions; the study results indicate that CT may be an essential procedure for its evaluation.