Richard H. Greenspan

Accuracy of the chest radiograph in diagnosis of pulmonary embolism.

In an effort to determine the sensitivity and specificity of the chest roentgenogram for the diagnosis of pulmonary embolism, roentgenograms of 152 patients who were all suspected of having pulmonary embolism were randomized and presented to nine interpreters. One hundred eight patients in the series were proven to have pulmonary embolism on the basis of a positive pulmonary angiogram. Forty-four patients were assumed not to have embolism on the basis of either a normal perfusion isotope scan or a pulmonary angiogram which did not show embolism. The interpreters were requested to indicate whether pulmonary embolism was present or absent, or whether they could not tell from the roentgenogram. Readers had no prior knowledge of the actual disease state. The average true-positive ratio, (sensitivity) was 0.33, with a range of 0.52 to 0.88. The average true-negative ratio (specificity) was 0.59, with a range of 0.31 to 0.80. The false-positive and false-negative ratios were respectively, 0.21 (range 0.05 to 0.39) and 0.41 (range 0.15 to 0.70). A predictive index, reflecting the overall accuracy of diagnosis, was calculated for the entire group and was 0.40, with a range of 0.17 to 0.57. There appeared to be no correlation between training or experience and accuracy of performance in this study.

An Angiographic Severity Index for Pulmonary Embolism

This report has discussed the use of an angiographic severity index for pulmonary embolism in the analysis of pulmonary angiograms from 160 patients admitted to the Urokinase-Pulmonary Embolism Trial. Angiographic studies done before and after treatment with urokinase or heparin were analyzed independently by three radiologists who had no knowledge of treatment assignment. A subjective evaluation and a subsequent objective recording of abnormalities were made. The computation of a severity index was based on a numerical grading system for definite abnormalities specific for pulmonary embolism (intraluminal filling defects and vascular obstructions).The procedure for computing the severity index was simple enough that recorded abnormalities were coded and punched by a statistical clerk and analyzed by computer. Correlations between subjective evaluations and objective severity indices were high. There was excellent agreement among the three radiologists for both subjective and objective methods. Highly significant treatment differences were detected.The angiographic severity index might help to classify patients, predict prognosis, plan clinical studies, and assess treatment effects.

Nonuniform pulmonary arterial perfusion. Pulmonary embolism

Seven case reports exemplify various cardiac and pulmonary disorders which produce diminished, delayed, or absent filling of pulmonary arteries in a portion of the lung. These disorders are not uncommon in patients studied angiographically for possible pulmonary emboli. Only when the embolus itself is demonstrated as an intraluminal filling defect on pulmonary angiography is its definite diagnosis possible. Diagnosis of pulmonary embolism based solely on diminished perfusion, whether detected by radionuclide photo-scans or by pulmonary angiography, may be erroneous.

In vivo magnification angiography.

The combination of direct magnification with angiography extends the limits of visibility to fine vascular branches. Lesions not seen using conventional techniques can be detected. Utilizing a special tube, the technique is clinically feasible at the time of conventional angiography. This report describes the special equipment requirements and the technique used in obtaining magnification angiograms and presents some examples of the results obtained.

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.

Radiographic differentiation between different etiologies of pulmonary edema.

We compared the plain chest radiographs of critically ill patients who had different types of pulmonary edema and evaluated the radiographs according to a standardized score sheet of findings. We included 94 total cases of pulmonary edema: 49 with cardiogenic, 33 with permeability, and 12 with renal/overhydration pulmonary edema. Patients with cardiogenic edema had enlarged hearts, vascular engorgement, septal lines, and absence of air bronchograms significantly more often than patients with permeability pulmonary edema. Renal/overhydration patients had enlarged hearts significantly more often than patients with permeability edema. There were no other statistically significant differences. Heart size and presence or absence of septal lines could have been used to distinguish cardiogenic and permeability edema in 83% of cases.

The advantages of direct magnification technic in the newborn chest.

The roentgenographic examination of the newborn chest is difficult because of the small size of the structures and lesions to be evaluated. The premature infant further intensifies this difficulty. The problem does not limit itself to the question of seeing information that is there, for at times this may be partially remedied by a magnifying glass or other means of indirect magnification. The problem includes the inability to resolve structures that are usually seen in older children and adults, as well as the poor definition of densities which even when indirectly magnified remain ill-defined and uninterpretable. Leinbach (1) in a study of the diameter of pulmonary artery branches in normal chest films of children had great difficulty with those under one year of age, for arterial visualization was too poor for measurement. The problem of distinguishing between vascular and parenchymal abnormalities in the newborn has also been a chronic one. An example of this has been the difficulty in differentiating...

Chronic disseminated alveolar diseases of the lung

Abstract Chronic diseases producing a disseminated alveolar roentgen pattern are not common, representing either infrequent manifestations of widespread diseases, or rare conditions. Symptomatology frequently bears little relation to the degree of abnormality on the roentgenogram. Both pathologically and radiologically, the alveolar phase of the disease is not stationary, but tends to regress, leaving normal lungs, or to progress to interstitial fibrosis. The presence of alveolar disease does not mean that interstitial disease is absent. Interlobular septal thickening frequently accompanies these diseases, and may appear prior to the development of obvious pulmonary fibrosis. Many of the diseases producing an alveolar pattern are difficult to diagnose clinically, and the detection of this pattern on the roentgenogram may be a most important diagnostic clue.

Ventilatory Pumping of Human Pulmonary Lymphatic Vessels

Ethiodol was injected into pleural lymphatics of lungs post- mortem in order to opacify deep lymphatics and thus determine the existence of ventilation-related pumping. Radiographs showed the lymphatics (a) during a period without flow, with the lung at a fixed inflation level, and (b) after ventilation within a normal range. Ventilation by both positive and nega- tive pleural pressure produced forward flow in deep lymphatics which had been filled while the lung was at a low volume (functional residual capacity). Ven- tilation did not produce flow in deep lymphatics which had been filled while the lung was at a higher volume (70% total lung capacity).

Roentgenographic Study of the Human Trachea with Powdered Tantalum

Abstract Powdered tantalum proved a superior tracheographic contrast material in 10 patients with symptomatic tracheal stenosis. It permitted assessment of degree of stenosis and extent of mucosal changes above and below the lesion. Only a small volume of the highly radiopaque material is required, and risk to the patient is minimal. The particles adhere to the mucosal surfaces and are not dislodged by cough or deep respiration. No deleterious effects on the respiratory function were noted, and the material appears biologically and clinically inert. Particles were cleared from the airways within six hours in all cases.