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Biomedical subjects

C Chiles

Publications and source records attributed to C Chiles.

At least 55 records · Page 3Linked to original sources
PubMed1987

Invasive pulmonary aspergillosis: radiologic evidence of tracheal involvement.

Chest radiographs of invasive pulmonary aspergillosis in immunocompromised patients typically show ill-defined pulmonary nodules. Direct tracheal involvement has not been previously documented radiologically. Radiographs and CT scans of a 16-year-old boy with aplastic anemia and invasive pulmonary aspergillosis showed increased paratracheal opacity, tracheal narrowing, and pneumomediastinum in combination with pulmonary disease. Bronchial lavage cultures grew Aspergillus fumigatus, and the boy died 24 days later.

Adolescent↗
PubMed1987

The radiographic distinction between pericardial and myocardial calcifications.

Calcification overlying the left side of the heart on a chest radiograph may involve either the pericardium or, alternatively, the myocardium in association with a left ventricular aneurysm. Distinction between these two conditions can be of great clinical significance. To identify distinguishing features, we reviewed the radiographs and medical records of 29 patients: 14 had proven calcific pericarditis and 15 had proven calcified left ventricular aneurysm. Pericardial calcification was found primarily over the right-sided cardiac chambers (14 of 14 patients) and in the atrioventricular grooves (11 of 14), infrequently over the base of the left ventricle (five of 14), and rarely over the apex of the left ventricle (two of 14). When the left ventricle was involved, there was always more extensive calcification elsewhere in the pericardium. Myocardial calcification occurred predominantly in the apex of the left ventricle (13 of 15 patients), although it was rarely confined to the posterior wall of the left ventricle (two of 15). By noting characteristic sites of calcium deposition, pericardial calcification can be effectively distinguished from myocardial calcification. Isolated calcification in the region of the left ventricular apex, therefore, strongly suggests left ventricular aneurysm.

Adolescent↗
PubMed1986

Radiographic recognition of pneumothorax in the intensive care unit.

Recognizing pneumothorax and hydropneumothorax on chest x-rays of supine ICU patients requires attention to areas other than the lung apex. Pleural air in a supine patient collects in the anterior costophrenic sulcus, producing hyperlucency over the upper abdominal quadrants, and the deep costophrenic sulcus sign. Hydropneumothorax may be recognized when a sharp pleural line is bordered by increased opacity within the pleural space. The presence of pneumothorax and hydropneumothorax can be confirmed by decubitus or upright chest x-rays.

Critical Care↗
PubMed1986

Distribution of 15- and 137-mu diameter microspheres in the dog lung in the axial plane.

Oleic acid infusion, as a model of fat embolism, produces a predominantly peripheral lesion in the dog lung. The lung injury corresponds to the peripheral distribution of labeled oleic acid. The basis for this distribution of oleic acid is not known. Our hypothesis for this nonuniform distribution is that particle diameter plays a role in the subsequent distribution of infused oleic acid and the resulting lung injury. We injected 15-mu microspheres 85Sr and then 137-mu microspheres (141Ce) into the right atria of seven dogs, which were killed and the lungs removed. Analysis of the distribution of the two different diameter microspheres within axial slices from the left caudal lobe of each dog revealed a peripheral distribution of the larger diameter microspheres not seen with the smaller microspheres.

Animals↗
PubMed1986

Imaging of the axillary subsegment of the right upper lobe.

The bronchial supply of the lateral or axillary area of the right upper lobe is variable. In 16 percent of normal subjects, an independent ramus of the posterior right upper lobe bronchus supplies an axillary subsegment. Airspace disease in the axillary subsegment has a characteristic appearance on radiographs. The CT appearance of disease in the axillary subsegment correlates closely with classic anatomic studies. Recognizing that disease is located in the axillary subsegment can help in directing bronchoscopy or biopsy.

Bronchial Diseases↗
PubMed1985

Anterior chest wall mass in an elderly male.

A case of chondrosarcoma arising from the right anterior second rib in an 84-year-old man is described. Radiographic features include amorphous calcification within a chest wall mass. CT findings include calcification and necrosis within the 8 X 8 X 10 cm tumor, and extension into the adjacent lung. The presence of zones of dedifferentiation into fibrosarcoma in the surgically resected tumor indicates a poor prognosis, with a high likelihood of early recurrence and pulmonary metastasis.

Aged↗
PubMed1985

Digital synthesis of lung nodules.

Studies evaluating observer accuracy and visual perception of pulmonary nodules usually are based upon test films obtained from clinical practice in patients with proven pulmonary nodules. Unfortunately, such nodules do not always occur in the optimal size and location to facilitate testing. Such studies would be enhanced by the ability to place nodules of desired size and location on chest radiographs. This report describes a method of placing a computer-generated (synthesized) nodule on a digitized chest radiograph. To demonstrate the similarity of these synthesized nodules to real nodules, each digitized radiograph with a computer-generated nodule was paired with a digitized chest radiograph of a patient with a clinically proven pulmonary nodule. A total of 22 pairs of chest radiographs were then shown to 13 radiologists, who were asked to distinguish the synthesized nodule from the real nodule. With this two alternative forced-choice test, the radiologists were only able to distinguish the synthesized nodule in 51% of the cases, strongly suggesting that computer generated nodules may be used to simulate real pulmonary nodules in future tests of nodule detection.

Humans↗
PubMed1985

Heart-lung transplantation: the postoperative chest radiograph.

The postoperative chest radiographs of 10 patients who had undergone heart-lung transplantation at Stanford University Medical Center were evaluated and compared with those of 10 consecutive cardiac transplantation patients and 10 consecutive coronary artery bypass graft patients. In the second week after surgery, we observed an interstitial radiographic pattern in the heart-lung transplantation patients but not in the other two patient populations. This pattern, which did not correspond with any clinical evidence of infection, rejection, fluid overload, or oxygen toxicity, may represent the reimplantation response described in dogs and primates following transplantation of a single lung. This response may be related to the interruption of bronchial circulation, the denervation of both lungs, and the lymphatic interruption that occur during transplantation. It may also be related to the obligatory period of ischemia that is incurred during implantation.

Adult↗
PubMed1985

Evaluation of the portable chest roentgenogram for quantitating extravascular lung water in critically ill adults.

The diagnosis of pulmonary edema is frequently made from characteristic findings on the chest roentgenogram that suggest an increase in lung water. Optimal radiographic technique depends on a cooperative upright patient, which is not possible with most critically ill patients. These patients may also have multiple radiographic abnormalities that make interpretation of the chest roentgenogram difficult. The ability of portable chest roentgenograms to accurately identify the presence of excess lung water and monitor changes in lung water has not previously been evaluated in critically ill adults who are intubated and ventilated and in the supine position when the films are exposed. In 12 patients the pulmonary edema seen on portable chest roentgenograms was given a score (0 to 390 points), which was then compared with a determination of extravascular lung water using the thermal-dye indicator dilution technique. A linear correlation was observed (r = 0.51; p less than 0.05; n = 73). Evaluation of a change in radiographic score vs a change in lung water showed no linear correlation (r = 0.1; p greater than 0.05). While portable chest roentgenograms exposed under the conditions described were a useful technique for demonstrating pulmonary edema, they were not accurate in monitoring modest changes in lung water in critically ill patients.

Adult↗
PubMed1985

Right atrial appendage pacing: radiographic considerations.

Transvenous pacing accomplished from the right atrial appendage, either alone or in combination with right ventricular pacing, is becoming increasingly popular for selected patients in whom the contribution of atrial systole is advantageous. On the frontal chest radiograph, the pacemaker is seen to terminate over the right upper heart border, often seeming to turn abruptly cephalad. On the lateral radiograph, the lead follows a smooth, smooth, anterior curve in the midportion of the heart with its tip angled cephalad into the right atrial appendage. Complications associated with the use of this form of transvenous pacing are similar to those seen with other transvenous pacemakers; in addition, the catheter may be positioned inadvertently in the body of the right atrium, resulting in less effective atrial pacing.

Cardiac Pacing, Artificial↗
PubMed1985

Radiographic manifestations of cardiac sarcoid.

On the basis of autopsy series, the incidence of direct cardiac involvement in sarcoidosis has been estimated to be 20%-27%. It may be recognized clinically when patients with known systemic sarcoidosis present with arrhythmias, conduction disturbances, or cardiomyopathy. Various radiographic manifestations of cardiac sarcoid, including cardiomegaly, pericardial effusion, and left ventricular aneurysm, are described in four patients.

Adult↗
PubMed1985

Intrathoracic metastasis from an extrathoracic malignancy: a radiographic approach to patient evaluation.

The likelihood of metastatic spread of an extrathoracic primary tumor to the thorax depends on a number of factors, most importantly, the site and nature of the primary tumor. Although the plain chest radiography remains the first-line screening procedure, understanding the pattern of spread of various tumors and the frequency with which such spread occurs enables one to develop a rational approach to the use of other imaging modalities, particularly computed tomography, in evaluation of patients with known extrathoracic primary tumors.

Bone Neoplasms↗
PubMedDate not supplied

Physical principles governing the interrelationships of pressure, flow and volume in collapsible tubes.

Basic principles of fluid mechanics may be used to analyze the relationships of flow, pressure and cross-sectional area of any collapsible tube, including pulmonary blood vessels. The cross-sectional area of a collapsible tube is a direct function of transmural pressure. Alterations in pressure inside the tube may result from changes in fluid velocity, downstream constriction in the tube, or direct increase in internal pressure, as with a manometer. This paper reviews the basic equations applicable to flow in collapsible tubes and illustrates the principles of such flow with a physical model. Depending upon the circumstances, changes in size of the tube may or may not reflect changes in flow or changes in fluid velocity.

Biophysical Phenomena↗
PubMedDate not supplied

Detection of pulmonary emboli in dogs using digital subtraction angiography.

Digital subtraction angiography (DSA) was performed in six dogs to define the limits of detection of pulmonary emboli. Three angiograms were initially obtained in three normal control animals, two of which were subsequently embolized. A total of ten pulmonary angiograms were then obtained in five dogs that had experimentally produced emboli of Ivalon cubes (2, 3, and 10 mm). The intravenous angiograms were followed by selective arterial angiograms to confirm the presence and location of the emboli. The intravenous angiograms were independently reviewed by two radiologists. The criterion for detection was identification of a vessel cutoff. Perfusion defects were also seen. No intraluminal filling defects were seen. This study indicates that pulmonary emboli greater than 2 mm in diameter may be detected in dogs by DSA.

Angiography↗
PubMedDate not supplied

CT demonstration of myocardial perforation by a pacemaker lead.

We report a case of perforation of the right atrium by a transvenous right atrial appendage pacemaker lead diagnosed by CT. Routine radiologic assessment was unable to demonstrate the perforation. Computed tomography is recommended in cases where pacemaker perforation is clinically suspected but not confirmed by conventional radiographic means.

Aged↗
PubMedDate not supplied

Case report. Chemical-shift MRI of exogenous lipoid pneumonia.

Exogenous lipoid pneumonia results from the aspiration or inhalation of fatty substances, such as mineral oil found in laxatives or nasal medications containing liquid paraffin. We present standard and lipid-sensitive (Chemical-shift) MR findings in a patient with histologically confirmed lipoid pneumonia. The loss of signal intensity in an area of airspace disease on opposed-phase imaging was considered specific for the presence of lipid.

Aged↗
PubMedDate not supplied

Localized benign fibrous tumors of the pleura: MR appearance.

PURPOSE: Our goal is to describe the MR findings in benign localized fibrous tumors of the pleura. METHOD: Chest radiographs, CT scans, and MR images of four patients with localized benign fibrous tumors of the pleura were retrospectively reviewed and correlated with the pathologic findings. RESULTS: Tumors ranged from 4 to 18 cm in their largest diameter. Three tumors were located in the diaphragmatic region, and one was within the left major fissure. All tumors were round to ovoid, pedunculated, and well delineated. On T1-weighted SE MR images, tumors showed low signal intensity. All tumors had heterogeneous but predominantly low signal intensity on proton-density-weighted images and lower signal intensity on T2-weighted images. CONCLUSION: Localized benign fibrous tumors of the pleura were characterized by low signal intensity on all MR sequences that is explained by high collagen content within the tumors' stroma and should suggest the diagnosis preoperatively.

Adult↗