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Biomedical subjects

E N Milne

Publications and source records attributed to E N Milne.

At least 19 recordsLinked to original sources

Pulmonary oligemia in aortic valve disease.

PURPOSE: To determine whether the severity of the radiographic appearance of oligemia correlates with the severity of cardiac dysfunction. MATERIALS AND METHODS: Nine readers graded a set of 25 chest radiographs (15 cases of aortic valve disease [AVD], 10 control cases without AVD) for blood volume and ventricular size. Blood volume was graded on a scale of -3 (severe hyperemia) to 0 (normovolemia) to +3 (severe oligemia). Ventricular size was graded on a scale of 0 (normal) to 3 (massively enlarged). The oligemia and ventricular size grades were added to yield the radiographic severity index. Pulmonary capillary wedge pressure, pulmonary arterial pressure, stroke volume, and cardiac output were measured at the time of catheterization. RESULTS: The five more experienced readers achieved good nonchance agreement (kappa = 0.48; P < .001). They were unanimous in scoring 12 cases as oligemic; variations occurred only in severity assessments. Oligemia was due to emphysema in one case and to AVD in 11. In oligemic cases, radiographic severity correlated significantly with wedge pressure (r = 0.93, P < .001) and pulmonary arterial pressure (r = 0.93, P < .002). CONCLUSION: Many cases of AVD show oligemia. The severity of oligemia correlates well with hemodynamic abnormality. Oligemia may be caused by atrial-pulmonary-vascular reflex vasoconstriction, low right ventricular output, and possibly high levels of atrial natriuretic factor.

Adult↗

Radiographic evidence of interstitial pulmonary edema after exercise at altitude.

Pulmonary function abnormalities after exercise are suggestive of pulmonary edema; however, radiographic evidence is lacking. Well-trained cyclists were studied to determine whether there is radiographic evidence of pulmonary edema after endurance exercise (cycling distance 5.3-131.5 km) at altitude. Chest radiographs obtained before exercise were coded for later interpretation. Films obtained after exercise were coded with a different number. A total of 74 sets of posteroanterior and lateral films were analyzed by three radiologists for signs of pulmonary edema. Radiographic changes were graded on a three-point scale. An edema score was calculated by summing the score for each individual radiographic finding for each radiologist and an overall edema score representing the mean scores from all three radiologists. The overall edema score increased from 0.8 +/- 1.2 before exercise to 1.8 +/- 1.6 after exercise (P < 0.01). These results suggest that, after prolonged high-intensity exercise at moderate altitude, there is radiographic evidence of early pulmonary edema in some cyclists.

Adolescent↗

Radiologic evaluation of emphysema in patients with chronic obstructive pulmonary disease. Chest radiography versus high resolution computed tomography.

To objectively reappraise the role of the chest radiograph (CXR) in the clinical assessment of emphysema, we compared a standardized reading of CXR with both a visual scoring and a quantitative analysis of high resolution computed tomography (HRCT) of the chest in 46 consecutive patients with chronic obstructive pulmonary disease (COPD) and fixed expiratory airflow limitation. CXR were scored for signs of overinflation and pulmonary vascular deficiency by three independent observers. HRCT scans were independently scored for extent of emphysema and for both severity and extent of emphysema. In 28 of 46 patients, inspiratory and expiratory HRCT scans were analyzed quantitatively by measuring the mean CT number in Hounsfield Units (HU) and the percentage of lung area with CT numbers < -900 HU. Quantitative CT data were compared with reference values obtained in seven normal nonsmokers. The CXR score of emphysema showed a highly significant interobserver reproducibility and correlated linearly (p < 0.001) with HRCT visual scores and quantitative data from both inspiratory and expiratory CT scan. CXR score correlated with functional indices of airflow obstruction, overinflation, and impaired lung diffusing capacity in a way comparable to that obtained by using qualitative and quantitative CT data. Patients with no signs of emphysema on CXR had mean expiratory CT numbers within normal range and a fraction of lung area with CT numbers < -900 HU on expiratory scan not exceeding 15% of total cross-sectional area. The latter value was consistently greater than 15% in patients with CXR score > 0.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Thoracoscopic laser ablation of pulmonary bullae. Radiographic selection and treatment response.

The purpose of this study was to develop objective preoperative selection methods for predicting outcome in patients undergoing thoracoscopic laser ablation of emphysematous pulmonary bullae. Initial radiographic presentation was correlated with physiologic function both before and after the operation in 24 patients entered into a prospective clinical protocol for evaluation of carbon dioxide laser treatment of emphysematous pulmonary bullae. Nineteen surviving patients underwent follow-up evaluation 1 to 3 months after the operation. Pulmonary function test results showed improvements in spirometry (forced vital capacity increased 0.82 +/- 0.125 L, forced expiratory volume in 1 second increased 0.36 +/- 0.07 L, and maximum voluntary ventilation increased 11.69 +/- 2.6 L/m; p < 0.002); airway resistance decreased by 0.9 +/- 0.35 cm of water/L per second, and specific conductance increased 0.019 +/- 0.006 L/cm H2O per second (p < 0.02). Lung volumes improved (residual volume decreased 1.25 +/- 0.23 L, p < 0.001) without significant change in resting gas exchange. Quantitative radiographic grading of extent of preoperative pulmonary bullae correlated well with response to laser treatment in patients with preoperative and postoperative studies. Patients with large bullae accompanied by crowding of adjacent lung structures, upper lobe predominance, and minimal underlying emphysema had greatest improvement in pulmonary function results with laser bullae ablation (p < 0.05). However, some patients with multiple smaller bullae and diffuse emphysema also demonstrated objective improvement after operation. Quantitative radiographic analysis of the extent of bullous disease and the degree of associated emphysema can be used to determine short-term postoperative pulmonary response and may be useful in selecting future thoracoscopic laser bullae ablation candidates. Additional follow-up will be necessary to further improve selection criteria and help define the long-term role of thoracoscopic laser treatment of bullous emphysema.

Aged↗

Objective radiographic criteria to differentiate cardiac, renal, and injury lung edema.

To assess the value of the chest radiograph in differentiating various types of pulmonary edema, we retrospectively analyzed 119 films of patients with pulmonary edema caused by left heart decompensation (group 1;N = 56), renal failure (group 2; N = 19), and lung microvascular injury (group 3; N = 44). Chest radiographs were examined independently by two trained observers, unaware of the clinical diagnosis, according to a standardized reading table. The two observers assigned chest films to the corresponding group with an accuracy of 86% and 90%, respectively. To test the observers' objectivity, we used radiographic findings as input variables for discriminant analysis. Computer-generated numerical functions identified pulmonary edema etiology with an accuracy of 88% when considering the three groups together. When groups were compared as pairs, percentages of correct classification were 91% (group 1 vs. group 2), 93% (group 1 vs. group 3), and 100% (group 2 vs. group 3). Thus, a standardized reading of chest radiographs may be considered a reliable clinical method for identifying pulmonary edema etiology.

Heart Failure↗

A case report of segmental bronchial atresia: radiologic evaluation including computed tomography and magnetic resonance imaging.

Bronchial atresia is a rare anomaly that characteristically presents with a pulmonary nodule and hyperinflation of the lung distal to the nodule. To make this diagnosis definitively, invasive studies have been required. Now with the combined use of computed tomography and magnetic resonance imaging, a diagnosis can be made without resorting to invasive techniques. This article describes a case of bronchial atresia illustrating the noninvasive approach.

Adult↗

Role of imaging and interventional techniques in the diagnosis of respiratory disease in the immunocompromised host.

A pure "pattern-recognition" approach to lung diseases in immune compromised patients as seen on the chest film is of limited value since any infection can present with several different patterns, and processes such as embolism, aspiration, edema, and hemorrhage may give appearances similar to infection. However certain pulmonary infections do occur commonly in association with one type of immunosuppression but rarely with others. Knowledge of these associations assists in narrowing down the differential diagnosis and in deciding upon the most appropriate next confirmatory diagnostic step.

Acquired Immunodeficiency Syndrome↗

Splenic size on routine chest films in AIDS: diagnostic and prognostic significance.

Sixty-nine percent of AIDS patients show evidence of splenomegaly on their plain chest film. This splenomegaly is not related to severity of AIDS, to intravenous drug abuse or to any specific infection or neoplasm but correlates well with severity of anemia, pancytopenia, and thrombocytopenia. Increasing splenomegaly usually indicates worsening of AIDS. The triad of splenomegaly, interstitial lung disease sparing the bases, and very thin chest wall soft tissues is highly specific for the diagnosis of AIDS. The sensitivity of the plain film for diagnosing AIDS can be increased by including AIDS in the differential diagnosis of all patients with splenomegaly, intrathoracic lymphadenopathy, cachexia, or bilateral interstitial lung disease of unknown cause.

Acquired Immunodeficiency Syndrome↗

Assessment of cardiac size on portable chest films.

Using both anthropomorphic phantoms and human patients, the authors have shown that the effects on cardiothoracic (CT) ratio of changing from the posteroanterior (PA) to the anteroposterior (AP) projection are much greater than the effect of reducing the anode-to-film distance (AFD). This is because, in the AP projection, not only is the transverse diameter (TD) of the heart much farther from the film (and its image is therefore enlarged), but the TD of the chest is usually closer to the film and its image is reduced in size. These factors, operating in different directions, cause a major change in the CT ratio. The authors have shown that small hearts are magnified more than large hearts by changing from PA to AP, and that the position of the TD of the thorax (whether it is farther anterior or farther posterior) markedly affects what happens to the CT ratio when the AFD is changed. Because of this, it is impossible to predict accurately what effects a given AFD and projection will have on the CT ratio. However, using approximate correction factors (-12.5% of CT ratio for a 40 in AFD, AP film and -10% of CT ratio for a 72 in AFD, AP film) a clinically useful determination can be rapidly made as to whether the heart is enlarged or not.

Cardiomegaly↗

Factors affecting regional pulmonary blood flow in chronic ischemic heart disease.

To assess the effect of left heart disease on pulmonary blood flow distribution, we measured mean pulmonary arterial and wedge pressures, cardiac output, pulmonary vascular resistance, pulmonary blood volume, and arterial oxygen tension before and after treatment in 13 patients with longstanding ischemic heart failure and pulmonary edema. Pulmonary edema was evaluated by a radiographic score, and regional lung perfusion was quantified on a lung scan by the upper to lower third ratio (U:L ratio) of pulmonary blood flow per unit of lung volume. In all cases, redistribution of lung perfusion toward the apical regions was observed; this pattern was not affected by treatment. After treatment, pulmonary vascular pressures, resistance, and edema were reduced, while pulmonary blood volume did not change. At this time, pulmonary vascular resistance showed a positive correlation with the U:L ratio (r = 0.78; P less than 0.01), whereas no correlation was observed between U:L ratio and wedge pressure, pulmonary edema, or arterial oxygen tension. Hence, redistribution of pulmonary blood flow, in these patients, reflects chronic structural vascular changes prevailing in the dependent lung regions.

Blood Volume↗

Blood supply of pulmonary metastases.

There is a widely held belief that metastases to the lung (like primary lung tumors) are supplied by the bronchial arteries and that pulmonary neovascularization does not occur. In 17 human lungs, we have demonstrated, both in vitro and in vivo, pulmonary circulation to metastases. We have confirmed this in a series of animal studies in which we implanted tumors of various histologies into rats' tails and induced metastases from these tumors into the lungs. Forty-eight percent of these metastases had an entirely pulmonary circulation, 36% a primarily pulmonary circulation with a small bronchial component, and only 16% of metastases, located in the central one third of the lung, had an exclusively bronchial circulation. We have now shown that these supplying pulmonary vessels to metastases can be clearly demonstrated on thin-section computed tomography of the lungs. This may prove to be a helpful, noninterventional diagnostic criterion for distinguishing a primary from a metastatic lesion.

Animals↗

A physiological approach to reading critical care unit films.

Radiologic assessment of pulmonary vascular pressure and flow and quantitation and determination of the etiology of pulmonary edema is reviewed and new data provided to calculate "true" cardiac size from portable films. The quantitation of changes in intra- and extravascular water and a more accurate approach to the assessment of left atrial pressure are discussed and new anatomical observations offered to explain post-operative left lower lobe atelectasis, and severe soft tissue emphysema which may follow chest tube insertion in a patient with very stiff lungs. Radiographic data have now been shown to be sufficiently objective so that when a discrepancy occurs between the radiologic analysis and laboratory data, the laboratory data should be cross-checked and its accuracy confirmed before treatment based on these data alone is instituted.

Blood Pressure Determination↗