Diagnostic value of chest radiography for pericardial effusion.

OBJECTIVES: This study was designed to determine the diagnostic value of chest radiography for pericardial effusion. BACKGROUND: Pericardial effusions may cause life-threatening cardiac complications, yet they are often difficult to diagnose. METHODS: In a blinded manner, we reviewed the chest radiographs of 83 patients with echocardiographically diagnosed pericardial effusions (5 large, 18 moderate, 60 small) and those of 17 control subjects without effusions. We examined four radiographic signs: an enlarged cardiac silhouette, a pericardial fat stripe, a predominant left-sided pleural effusion and an increase in transverse cardiac diameter compared with the diameter on a previous chest radiograph. RESULTS: An enlarged cardiac silhouette was moderately sensitive (71%) but not specific (41%) for pericardial effusion. A pericardial fat stripe, a predominant left-sided pleural effusion and an increase in transverse cardiac diameter were all specific (94%, 100% and 80%, respectively) but not sensitive (12%, 20% and 46%, respectively). A predominant left-sided pleural effusion was associated with pericardial effusions of all sizes (odds ratio = 1.3, 95% confidence interval [CI] = 1.0-1.6, p = 0.04) and with large and moderate pericardial effusions alone (odds ratio = 7.7, 95% CI = 2.5-24.0, p = 0.0004). In contrast, a pericardial fat stripe was associated only with large and moderate pericardial effusions (odds ratio = 3.3, 95% CI = 0.9-12.0, p = 0.07), and an enlarged cardiac silhouette and an increase in cardiac diameter were not associated with pericardial effusion at all. CONCLUSIONS: A predominant left-sided pleural effusion and a pericardial fat stripe are chest radiographic signs that are suggestive, but not diagnostic, of pericardial effusion. Because these signs cannot reliably confirm or exclude the presence of pericardial effusion, we conclude that chest radiography is poorly diagnostic of this condition.

Constrictive pericarditis presenting as pleural effusion of unknown origin.

Despite the known association of pleural effusion with constrictive pericarditis, the presentation of constrictive pericarditis as pleural effusion of unknown origin has, to our knowledge, never been described. After evaluating such a case, we retrospectively analyzed all cases of established constrictive pericarditis seen in this institution in the last six years. The clinical and laboratory features of this cohort of 30 patients are similar to those of other reported series. Pleural effusion was present in 18 (60%) of 30 cases. In six (12%) of the 18 cases, pleural effusion was a major component of the clinical presentation, and in three (10%) of these six cases, the persistence of pleural effusion of unknown origin was the indication for referral to this institution. Analysis of pleural fluid in four cases revealed three exudates and one transudate. We believe this is the first report of unexplained pleural effusion as the presenting manifestation of constrictive pericarditis, and this diagnosis should be added to the list of causes of unexplained pleural effusion.

Clinical nuclear magnetic resonance imaging of the body.

NMR promises great advances in diagnosis and has delivered so much already that it is expected that in the future it will replace many applications of the currently used imaging modalities. Although x-ray computed tomography is continuing to advance in speed of scanning and resolving power, NMR will most likely soon eliminate its use in many studies of the central nervous system and also in many other areas of the body. The promise of combining topical spectroscopy with imaging is also exciting and should provide further information about metabolic processes of various organs. Progress in NMR is so rapid and the future is so bright that one of the great problems will be to develop a new breed of radiologists who are versatile in biochemistry, mathematics, and computers, as well as competent in morphologic anatomy and pathologic physiology. As time goes on, advances in NMR will be achieved only by teams of clinical and basic scientists encompassing multiple disciplines.

Pneumomediastinum. An unusual complication of needle biopsy of the lung.

Pneumomediastinum without pneumothorax is an unusual and apparently benign complication of needle biopsy of the lung.

Postoperative mediastinal masses. Report of two cases.

A mediastinal mass can mimic the presence of cardiovascular disease by simulating cardiac or vascular enlargement on chest radiographs, or by compressing the heart or great vessels with resulting symptoms or signs. This problem of misdiagnosis is particularly acute in patients with prior cardiac surgery for repair of congenital heart lesions. Two such cases are reported. In addition tosimulating cardiac disease, at least one, and perhaps both, were related to prior mediastinal surgery.

Thoracic metastasis in malignant melanoma. A radiographic survey of 65 patients.

Sixty-five patients with malignant melanoma metastatic to the thorax were evaluated retrospectively. Chest x-ray films showed abnormalities in 63 patients and provided the first evidence of dissemination in 42 of the 62 with widespread metastasis. Frequent radiographic follow-up evaluations of patients with primary melanoma is necessary to detect metastasis at an early stage. Pulmonary metastasis was seen radiographically in almost 90 percent of the patients. Snowstorm metastasis denotes a poorer prognosis than other patterns of pulmonary involvement. Enlargement of mediastinal lymph nodes, bronchial obstruction with atelectasis, pleural effusion, bone metastasis with an extrapleural mass, and cardiomegally were also seen. Follow-up chest x-ray films are of limited value in evaluating patients once they are found to have thoracic metastasis. The rate of growth of metastatic lesions or the regression of the metastasis does not correlate with survival.

Resolution of pulmonary lymphangitic carcinoma of the breast.

Pulmonary lymphangitic carcinomatosis, a grave complication of malignant neoplasms, usually progresses rapidly and is fatal despite all modes of therapy. We recently observed complete resolution of pulmonary lymphangitic involvement from an adenocarcinoma of the breast following both chemotherapy and bilateral oophorectomy. The patient's chest radiograph has remained clear for 1 1/2 years.

Nonbronchoscopic bronchoalveolar lavage for the diagnosis for Pneumocystis carinii pneumonia in the acquired immunodeficiency syndrome.

We compared conventional bronchoscopic transbronchial biopsy (TBB) and bronchoalveolar lavage (BAL) with non-bronchoscopic bronchoalveolar lavage (NB-BAL) in nine patients with acquired immunodeficiency syndrome (AIDS) and bilateral lung infiltrates. NB-BAL was carried out with a control-tipped reusable catheter. In each patient, bronchoscopic procedures were performed in the right lung, followed immediately by NB-BAL in the left lung. The specimens obtained by NB-BAL confirmed the presence of P carinii pneumonia in seven of eight patients in whom the diagnosis was established by TBB or BAL. Viral cultures of NB-BAL specimens yielded cytomegalovirus (CMV) in four of five subjects with evidence of CMV via bronchoscopic technique, including two instances in which CMV was not detected by BAL. Complications were limited to right-sided pneumothorax attributable to TBB. Accuracy of NB-BAL appears to be comparable to that of conventional bronchoscopic approaches in the diagnosis of AIDS-related pulmonary infection with P carinii or CMV. NB-BAL may be a safer and more economical alternative to TBB and BAL in the diagnosis of pulmonary opportunistic infections.

Bronchoalveolar lavage as the exclusive diagnostic modality for Pneumocystis carinii pneumonia. A prospective study among patients with acquired immunodeficiency syndrome.

Pneumocystis carinii pneumonia (PCP) is the most common life-threatening opportunistic infection among patients with the acquired immunodeficiency syndrome (AIDS). Because retrospective studies suggested that bronchoalveolar lavage (BAL) compared favorably to lung biopsy in the diagnosis of PCP, we prospectively evaluated the utility of BAL in 40 consecutive patients with AIDS or risk of AIDS who presented with respiratory complaints. The BAL revealed P carinii in 36 of 42 episodes of pneumonia (86 percent) among 40 patients. Clinical follow-up of the six patients whose BAL was negative for PCP suggested only one possible false negative BAL for PCP. Therefore, BAL detected PCP in 36 of 37 patients for a sensitivity of 97 percent. BAL detected cytomegalovirus in 15 of 38 patients, as well as Mycobacterium avium-intracellulare and Cryptococcus (each in one patient). By virtue of accuracy and lack of morbidity demonstrated in our study, BAL should supplant lung biopsy techniques in the evaluation of AIDS patients with pulmonary symptoms.

Dynamic quantitative computed tomography. A predictor of pulmonary function in obstructive lung diseases.

RATIONALE AND OBJECTIVES: Nine patients were examined using dynamic electron beam computed tomography to assess the utility of this technique in detecting airway obstruction and air trapping, and to compare this technique with pulmonary physiologic testing. METHODS: Dynamic computed tomography (C-100 Ultrafast CT scanner, Imatron, Inc., South San Francisco, CA) was performed, with a series of ten, 100-msec images obtained in a 6-second period during forced inhalation and exhalation. Time-attenuation curves were calculated from the observed changes in lung attenuation. Estimates of the percentage of each lung that showed air trapping were made at each level scanned, using a 5-point scale. Specific correlations were made for pulmonary function test results and air-trapping score. RESULTS: In all nine patients, dynamic computed tomography demonstrated one or more sites that failed to show a normal increase in lung attenuation during forced exhalation. Four of these 9 patients showed a paradoxical decrease in lung attenuation during exhalation in at least one region of the lung. Extent of air-trapping correlated well with forced expiratory volume in one second (r = -.92). CONCLUSIONS: Based on this small sample, the authors believe that this technique will prove sensitive for detecting abnormalities of ventilation and may be a useful adjunct to conventional diagnostic procedures in the management of disorders of airway obstruction.

The effect of acute pulmonary edema on pulmonary vascular resistance: significance for the interpretation of dilated upper lobe vessels on chest radiographs.

Dilation of upper lobe pulmonary vessels is an important radiographic sign of acute, left heart failure. A prominent theory is that perivascular edema causes increased resistance at the lung bases and inverts the normal perfusion gradient such that upper lobe blood flow exceeds lower lobe flow. This theoretical increase in flow is thought to cause dilatation of upper lobe vessels. Previous experimental studies determined indirectly changes in resistance from changes in the perfusion gradient: Results were contradictory. We measured directly the effect of edema on resistance in isolated canine lungs. Resistance increased linearly with edema. The magnitude of increase was small, however, and insufficient to cause inversion of the perfusion gradient. Our data indicate that interstitial pulmonary edema does not cause significant redistribution of blood flow. We suggest that dilated upper lobe vessels are veins acting as pulmonary venous manometers, reflecting elevated left atrial pressure, not increased blood flow.

A preliminary study of MRI quantification of simulated calcified pulmonary nodules.

The potential of magnetic resonance imaging (MRI) quantification of calcium for the evaluation of pulmonary nodules was investigated in simulated nodules. Calcium salts do not contain mobile protons and thus have no signal on MR proton images. To determine whether the absence of signal from partially calcified nodules could be quantified, we studied simulated nodules containing known quantities of calcium salts. The soft tissue equivalent material was an agar-gelatin mixture (T1:1100-1500 msec; T2: 59-62 msec). In the first experiments, glass tubes were filled with the mixture, which contained suspensions of calcium carbonate (CaCO3) or silica dioxide (Si02), and were subjected to computed tomography (CT) scanning and MR imaging. In a second series of studies CaCO3 particles of various sizes (and therefore different surface-to-volume ratios) were similarly suspended and subjected to CT scanning and MR imaging. In a third series hydroxyapatite (HA) suspensions of different sizes were similarly studied. CaCO3 produced a significant reduction in MR hydrogen density and signal intensity of the agar-gelatin mixture. Reduction in T1 and T2 relaxation times was inconsistent and not related to particle size. CaCO3 produced its effect by soft-tissue displacement. HA (and Si02) caused a more marked fall in MR hydrogen density, signal intensity, and T1 and T2 relaxation times. The degree of the T1 and T2 effects was related to particle size, indicating a hydrophilic surface effect. The authors conclude that MRI quantification of calcium within pulmonary nodules (or other tissues) will be complex and will relate to the precise composition of the calcium salt and to the particle size of the aggregates.

Accelerated atherosclerosis during maintenance hemodialysis: detection from chest radiographs.

Evidence of accelerated atherosclerosis was studied from chest radiographs of 26 patients on maintenance hemodialysis. The aortic knob was observed for presence of and increase in calcified plaques. At the initiation of hemodialysis, the degree of aortic calcification was no different from that seen in the control group. After periods ranging from one and a half to eight years, the patients on hemodialysis showed a significantly greater amount of aortic calcification and a significantly higher rate of calcification. The degree of calcification correlated with the severity of cardiovascular disease as determined clinically. For patients on maintenance hemodialysis, close scrutiny of serial chest-radiographs may help to identify those who are at greater risk for life-threatening cardiovascular disease.

Absolute lung density in experimental canine pulmonary edema.

The noninvasive quantification of pulmonary edema could be of importance in patient management. We have developed a portable Compton-scatter densitometer capable of measuring density in the range of 0.1-1 g/cm3 independently of the chest wall. Change in lung density was investigated in 19 dogs with pulmonary edema induced by a combination of raised left atrial pressure and hemodilution. The increase in lung density correlated with the postmortem assessment of lung water (r = 0.862, p less than 0.01) and with hemodynamic indicators of pulmonary edema (r = 0.749, p less than 0.01). Subtracting the intravascular component of lung density did not improve the correlation with postmortem lung water (r = 0.850, p less than 0.01). The measurement of absolute lung density by a Compton-scatter technique may be a potentially useful method of quantifying pulmonary edema.

Radiographically determined lung volumes at full inspiration and during dynamic forced expiration in normal subjects.

Posteroanterior and lateral radiographs of the lungs of 30 normal adults were obtained at total lung capacity (TLC) and 1 sec after initiation of forced expiration from ttlc. simultaneous spirographic recording of the volume expired (FEV-1) and independent plethysmographic recording of TLC were obtained. Two types of measurements were made from the radiographs: 1) surface areas of the lung fields, measured planimetrically; and 2) combinations of linear distances between selected points. These radiographic measurements and the measured lung volumes were subjected to computer analysis to develop reliable formulas for determining lung volumes solely from radiographs. Formulas derived using planimetry produced multiple correlation coefficients of 0.95 for TLC and 0.89 for volume during forced expiration. Use of linear measurements produced multiple correlation coefficients of 0.92 for TLC and 0.84 for dynamic volume. Thus, in normal subjects, static lung volumes and lung volumes during dynamic forced expiration can be determined from radiographs.

CT-determined pulmonary artery diameters in predicting pulmonary hypertension.

This study was to determine if the diameters of pulmonary arteries measured from computed tomographic (CT) scans could be used 1) as indicators of pulmonary artery hypertension and 2) as a reliable base for calculating mean pulmonary artery pressure. The diameters of the main, left, proximal right, distal right, interlobar, and left descending pulmonary arteries were measured from CT scans in 32 patients with cardiopulmonary disease and in 26 age- and sex-matched control subjects. Diameters were measured using a special computer program that could display a CT density profile of the artery and its adjacent tissues. The upper limit of normal diameter for the main pulmonary artery was found to be 28.6 mm (mean + 2 SD). In the patient group, the diameters were correlated with data from cardiac catheterization. In these patients, a diameter of the main pulmonary artery above 28.6 mm readily predicted the presence of pulmonary hypertension. The calculated cross-sectional areas of the main and interlobar pulmonary arteries (normalized for body surface area [BAS]) were found to give the best estimates of mean pulmonary artery pressure (r = 0.89, P less than 0.001 and r = 0.66, P less than 0.001). Multiple regression analysis gave the useful equation: mean pulmonary artery pressure = -10.92 + 0.07646 X area of main pulmonary artery/BSA + 0.08084 X area of the right interlobar pulmonary artery/BSA (r = 0.93, P less than 0.0001). Because CT allows precise, noninvasive measurement of the diameter of pulmonary arteries, it can be of value in detecting pulmonary hypertension and estimating mean pulmonary artery pressure.

CT of a bronchial phantom. Factors affecting appearance and size measurements.

In order to determine the most appropriate window settings for viewing CT of the bronchial tree, we performed CT of a bronchial phantom consisting of air-filled tubes measuring from 3.1 to 12.7 mm, oriented at varying angles relative to the scan plane, surrounded by water or air, and with scan collimation of 10 mm, 5 mm, and 1.5 mm. Using a computer program to graphically display CT number relative to the distance across the tube's lumen, it was found that a window mean of -150 H accurately estimated the internal diameter of tubes surrounded by water, at all angles, when collimation was 5 mm or 1.5 mm. With 10-mm collimation, tube diameter was slightly underestimated for tubes 9.5 mm or less when oriented 30 degrees or more from perpendicular to the plane of scan. At lower window settings and window widths of 500 H or less, all tube's diameters were significantly underestimated. At -150 H, with tubes parallel to and centered in the scan plane, 5-mm and 1.5-mm collimation were most accurate; with decentering of 4 mm, 10-mm collimation better showed the tube's lumen. When surrounded by air, tube wall thickness was best estimated using a window mean of -450 H.

Carcinoids associated with multiple endocrine neoplasia syndromes.

Carcinoids occur in association with MEN types 1 and 2. To determine the relationship between carcinoids and MEN, we reviewed nine patients with carcinoids and other endocrine tumors. Analyzing these 9 patients and 56 other patients previously described in the literature, we found several clinically important relationships. In contrast to the usual midgut and hindgut origin, most carcinoids associated with MEN (69 percent) are of foregut origin (thymus 24 percent, bronchus 27 percent, stomach 3 percent, and duodenum 14 percent). Carcinoids are more commonly associated with MEN type 1 than MEN type 2 (59 patients and 6 patients, respectively). Thymic carcinoids associated with MEN are more common in men (15 versus 2), and most (82 percent) are malignant. Bronchial carcinoids associated with MEN are more common in women (15 versus 4), and most (74 percent) are benign. There is a strong association between thymic carcinoids and parathyroid tumors and between bronchial carcinoids and pituitary tumors. Most patients with carcinoids and hyperparathyroidism (82 percent) have had parathyroid hyperplasia or multiple parathyroid adenomas. Thus, carcinoids may occur in association with both MEN type I and MEN type II. MEN should be suspected in patients with foregut carcinoids. Patients with MEN and ectopic ACTH production should be considered to have bronchial carcinoids if they are female and thymic carcinoid if they are male. The thymus should be routinely removed in patients with MEN type I because of the possible presence of an ectopic parathyroid gland in this tissue and to prevent subsequent development of a carcinoid tumor.

Determination of obstructive site in obstructive sleep apnea.

Patients with obstructive sleep apnea syndrome (OSAS) may have airway obstruction at various levels, including the uvula-soft palate complex, base of tongue, and/or possibly other sites. For patients with tongue base and/or laryngeal obstruction, uvulopalatopharyngoplasty (UPPP, ppp) will not alleviate the obstruction. Prior authors have proposed that the hyoid bone position as determined by cephalometric x-rays can predict which patients have obstruction at a lower site than the soft palate. In this study, patients with obstructive sleep apnea syndrome were evaluated with polysomnographic testing, fiberoptic endoscopy, and cine-CT scans (Imatron Scanner with multiple level rapid sequence scans) in an attempt to determine precisely the site of airway obstruction. Measurements of airway size taken at the time of fiberoptic pharyngoscopy were compared with those determined by the cine-CT studies. Initial results revealed that fiberoptic pharyngoscopy in the sitting and supine positions was helpful in confirming pharyngeal airway sites with smaller diameters in awake patients. However, the cine-CT exam performed in both sleeping and awake states provided more direct data regarding the airway during sleep. We feel that with more clinical experience the cine-CT technique will prove to be the most helpful study for identification of the obstructive airway site in obstructive sleep apnea syndrome.

High-resolution computed tomography of airway changes after induced bronchoconstriction and bronchodilation in asthmatic volunteers.

RATIONALE AND OBJECTIVES: We examined whether high-resolution computed tomography (HRCT) would detect and quantify induced airway changes in asthmatic volunteers. METHODS: We performed pulmonary function tests and HRCT on eight asthmatic adults and two nonasthmatic control adults under three conditions: baseline, after methacholine inhalation, and after albuterol inhalation. Changes in pulmonary function, airway internal luminal diameter (AILD), and airway wall thickness (AWT) in the three conditions were compared. RESULTS: After methacholine inhalation, pulmonary function showed significant airflow obstruction in the asthmatic volunteers compared with two nonasthmatic control volunteers. The median value for AILD decreased by 17% (p = .04). After subsequent inhalation of albuterol, pulmonary function improved to above the baseline levels in the eight asthmatic volunteers. The median value for AILD increased by 18% above the baseline value (p = .001). No changes in pulmonary function or AILD were seen in the two nonasthmatic volunteers. AWT did not change significantly in either the asthmatic or nonasthmatic volunteers after inhalation of methacholine or albuterol. CONCLUSION: HRCT can quantify changes in the internal luminal diameter of asthmatic airways provoked by methacholine and albuterol inhalation.