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Biomedical subjects

N R Dunnick

Publications and source records attributed to N R Dunnick.

At least 253 records · Page 14Linked to original sources
PubMedDate not supplied

Pulmonary embolism.

Pulmonary embolism is a common medical problem whose incidence is likely to increase in our aging population. Although it is life-threatening, effective therapy exists. The treatment is not, however, without significant complications. Thus, accurate diagnosis is important. Unfortunately, the clinical manifestations of pulmonary embolism are nonspecific. Furthermore, in many patients the symptoms of an acute embolism are superimposed on underlying chronic heart or lung disease. Thus, a high index of suspicion is needed to identify pulmonary emboli. Laboratory parameters, including arterial oxygen tensions and electrocardiography, are as nonspecific as the clinical signs. They may be more useful in excluding another process than in diagnosing pulmonary embolism. The first radiologic examination is the chest radiograph, but the clinical symptoms are frequently out of proportion to the findings on the chest films. Classic manifestations of pulmonary embolism on the chest radiograph include a wedge-shaped peripheral opacity and a segmental or lobar diminution in vascularity with prominent central arteries. However, these findings are not commonly seen and, even when present, are not specific. Even less specific findings include cardiomegaly, pulmonary infiltrate, elevation of a hemidiaphragm, and pleural effusion. Many patients with pulmonary embolism may have a normal chest radiograph. The chest radiograph is essential, however, for two purposes. First, it may identify another cause of the patient's symptoms, such as a rib fracture, dissecting aortic aneurysm, or pneumothorax. Second, a chest radiograph is essential to interpretation of the radionuclide V/Q scan. The perfusion scan accurately reflects the perfusion of the lung. However, a perfusion defect may result from a variety of etiologies. Any process such as vascular stenosis or compression by tumor may restrict blood flow. In addition, areas of the lung that are not well ventilated will be poorly perfused. Thus, a ventilation scan and a chest radiograph are essential to optimal interpretation of the perfusion scan. Ventilation/perfusion scans are interpreted as degrees of probability of pulmonary embolism. Emboli are not present in patients with a normal V/Q scan. An embolus is unlikely (10%-15%) among patients with a low-probability V/Q scan. However, small emboli that are nonocclusive may be present, and pulmonary arteriography may be used to further evaluate patients with a high clinical suspicion of pulmonary embolus.(ABSTRACT TRUNCATED AT 400 WORDS)

Angiography↗
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Computed tomography of the normal seminal vesicles.

Fifty patients without pelvic pathology were studied in order to determine the normal appearance of the seminal vesicles on computed tomography (CT). The seminal vesicles could be identified in all patients. The mean length of each seminal vesicle was 3.1 +/- 0.5 cm and the mean width was 1.5 +/- 0.4 cm. Calculated areas of the seminal vesicles assuming an ellipsoid shape were 3.6 +/- 1.1 cm2 for each side. When correlated with patients' ages, no significant difference was identified between age and the length of the seminal vesicles, however, a significant difference was noted between the widths (P less than 0.01) and areas (P less than 0.05) of the seminal vesicles with patients of increasing age having smaller seminal vesicles. In 67% of patients these structures were symmetrical and in 33% some degree of asymmetry was noted. Variability in shape ranged from ovoid (70%), tubular (20%), and rounded (10%). In 48 of 50 patients, small punctate densities could be seen along the lateral aspects of both seminal vesicles which correspond to the anatomic region of the pudendal venous plexus.

Adult↗
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Non-seminomatous testicular tumors: effect of lesion side on CT detection of lymph node metastasis.

Abdominal CT examinations of 40 patients with non-seminomatous testicular tumors were reviewed with previous knowledge of the side of the testicular primary. Metastatic nodes, between 1.5 cm and 2.0 cm in diameter were overlooked more frequently in patients with right than in those with left testicular primaries, because mildly enlarged aorto-caval or para-caval nodes (which are the most frequent site of metastasis from a right testicular lesion) were more difficult to detect than enlarged left para-aortic lymph nodes. Efforts to delineate the aorto-caval region on CT examinations of patients with right-sided lesions must be increased in order to reduce a surprisingly high false negative rate.

Adolescent↗
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Computed tomographic evaluation of an experimental model for pyogenic liver abscesses.

Computed tomography (CT) was used to evaluate 15 rabbits with experimentally induced liver abscesses. The animals were examined both before and after intravenous contrast injection. After sacrificing the animals, postfreeze CT scans were made to mark the abdomen for 1-cm thick whole body sections for correlating the gross pathology with the results of the CT scans. CT detected 15 abscesses in 13 of the 14 rabbits with true positive lesions. Ten abscesses less than 1.4 cm in diameter were not detected by CT. Contrast agent enhancement was helpful in 70% of the studies. These abscesses have characteristics similar to human liver abscesses, but there was more gas and calcium in the experimentally induced abscesses than is encountered in humans with hepatic abscesses. The model and its CT characteristics appear well suited for future studies in the diagnosis and treatment of liver abscesses.

Animals↗
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Biliary cytodiagnosis. Bile sampling for cytology.

The records of 121 patients who presented for PTC and biliary drainage within a five-year period were reviewed. Fifty-eight bile samples had been obtained from 38 of these patients for cytologic analysis. Malignancy was detected in 14 of 32 patients with carcinoma (sensitivity 44%). Repeat sampling was positive in four of nine patients whose initial specimen contained no tumor cells. Bile duct carcinoma, pancreatic carcinoma, and metastatic disease were all detected. An approach to biliary cytodiagnosis is offered that, it is hoped, will further minimize future false negative results.

Bile↗
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CT demonstration of an adrenal pseudocyst.

The CT and ultrasound findings in a case of an adrenal pseudocyst are reported. The pathology, etiology, usual manifestations, and differential diagnosis of adrenal cysts are discussed.

Adrenal Gland Diseases↗
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Computed tomography of primary retroperitoneal malignancies.

The CT examinations and medical records of 33 patients with primary retroperitoneal malignancies were reviewed. Computed tomography findings were then compared with those from scans performed on 122 patients with non-Hodgkin lymphoma who presented during the same time interval. Primary retroperitoneal neoplasms had three distinct CT appearances. Twenty-one patients (64%) had large soft tissue masses. Seven patients (21%) had masses with fatty density components, and five patients (15%) had tumors that were primarily of water attenuation. With the exception of those liposarcomas that contained recognizable fat, CT could not distinguish among the different cell types. Seventeen patients with non-Hodgkin lymphoma had large dominant retroperitoneal soft tissue masses that resembled primary retroperitoneal malignancies. In most cases, however, CT was able to differentiate these tumor masses from primary retroperitoneal tumors. Although 19 of 20 sarcomas of soft tissue attenuation were heterogeneous, only six of the 17 lymphomas presenting as dominant masses had such an appearance. Computed tomography is extremely helpful in initially evaluating patients with primary retroperitoneal tumors and in assisting the surgeon in planning his or her approach by accurately defining tumor extent.

Adolescent↗
PubMedDate not supplied

Computed tomography of renal lymphoma.

The CT studies of 29 patients with renal or perirenal lymphoma were retrospectively reviewed. Four patterns of disease were identified. Seventeen of 29 patients (59%) had bilateral renal masses. Only seven of these patients had associated enlarged retroperitoneal lymph nodes. Eight patients (28%) had single renal or perirenal lesions adjacent to or contiguous with bulky retroperitoneal lymphadenopathy. Three patients had infiltration of the perirenal space without significant renal parenchymal involvement, and one patient had a solitary renal mass. No patients in this series had diffuse involvement of the kidney without a focal mass. Renal involvement with lymphoma should be considered in any patient who develops multiple homogeneous solid renal or perirenal masses, even in the absence of other retroperitoneal disease.

Female↗
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Imaging of nontraumatic hemorrhage of the adrenal gland.

Nontraumatic hemorrhage of the adrenal gland is uncommon. The causes of such hemorrhage can be classified into five categories: (a) stress, (b) hemorrhagic diathesis or coagulopathy, (c) neonatal stress, (d) underlying adrenal tumors, and (e) idiopathic disease. Computed tomography (CT), ultrasonography (US), and magnetic resonance (MR) imaging play an important role in diagnosis and management. CT is the modality of choice for evaluation of adrenal hemorrhage in a patient with a history of stress or a hemorrhagic diathesis or coagulopathy (anticoagulant therapy). CT may yield the first clue to the diagnosis of adrenal insufficiency secondary to bilateral massive adrenal hemorrhage; such insufficiency is rare but life threatening. US is the modality of choice for evaluation of neonatal hematoma, and MR imaging is helpful for further characterization. MR imaging is also useful in the diagnosis of coexistent renal vein thrombosis. When an adrenal abscess is suspected, percutaneous aspiration and drainage under imaging guidance should be performed. Hemorrhage into an adrenal cyst or tumor can cause acute onset of symptoms and signs in a patient without discernible risk factors for adrenal hemorrhage. A hemorrhagic adrenal tumor should be suspected when CT or MR imaging reveals a hemorrhagic adrenal mass of heterogeneous attenuation or signal intensity that demonstrates enhancement.

Adrenal Gland Diseases↗
PubMedDate not supplied

Ultrasonic investigation of pancreatic islet cell tumors.

Ultrasonographic imaging was performed on 49 patients who had pancreatic islet cell tumors, including examples of all six known tumor varieties. In beta cell insulinomas, ultrasonography was of little value for tumor visualization, because these tumors tend to be small and the patients frequently are obese. On the other hand, ultrasonography was very effective for evaluating the nonbeta cell tumors, detecting both primary pancreatic neoplasms and hepatic metastases in patients with glucagonomas, somatostatinoma, non-functioning tumors, and the WDHA syndrome. In detection of the Zollinger-Ellison syndrome, ultrasonography compares favorably with previously reported gastrinoma detection by angiography and CT scanning.

Adenoma, Islet Cell↗