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Roentgenologic Aspects of Cardiac Disease
Roentgenologic Aspects of Cardiac Disease ROY R. GREENING, M.D., F.A.C.R. *
roentgen-ray examination of the heart and great vessels is but a part of the complete examination of a patient with cardiac disease. Conclusions based upon roentgenographic findings alone should never be regarded as conclusive, nor should one roentgen-ray examination be compared with another or with the electrocardiogram or the clinical evaluation of the patient. Each is only a part of a complete examination in which it is necessary to collect all available information, weigh, evaluate and add each fragment so that it will fit in its proper place in arriving at a final correct conclusion. At times it is necessary to carry out specialized procedures such as cardiac catheterization, with pressure studies and oxygen saturation measurements, and complete or segmental angiocardiographic or angiographic studies. Each of these latter studies is a complete subject in itself, requiring special complicated apparatus and knowledge, such that here they can only be mentioned in passing. The roentgen-ray examination of the heart and great vessels is a projection of a complicated three-dimensional shadow on a one-dimensional plane and as such does not lend itself to easy evaluation. Evidence has been collected for many years in an attempt to draw anatomic conclusions about certain cardiac contours as demonstrated upon such roentgenograms made at a conventional6-foot tube-film distance. From these studies have originated such terms as "mitral configuration" and "aortic configuration." Each of these so-called classic contours may be found in at least ten different conditions, so that one must finally conclude that there is no special configuration of the cardiac shadow pathognomonic of a particular kind of cardiac disease. THE
From the Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia.
* Assistant Professor in Radiology, University of Pennsylvania Graduate School of Medicine and University Hospital; Consultant, Jeanes Hospital, Philadelphia, and Coatesville General Hospital. 1575
1576
Ray R. Greening
Similarly, the measurement of cardiac size by single roentgenographic methods as an indication of cardiac disease is no longer a completely valid procedure. The use of tables giving percentages of eardiac enlargement in the posteroanterior roentgenogram of the chest is fraught with many difficulties, only some of which can be easily reconciled. Thus a narrow thorax or a depression of the sternum will falsely indicate an enlargement of the cardiac shadow. Similarly, variations in respiration or the presence of pulmonary emphysema may occasionally produce a false impression of large cardiac size, or an impression of a very small cardiac shadow which may be confused with that due to a condition such as Addison's disease. Either of these cardiac sizes may be perfectly normaL Pathologically, the determination of cardiac size may be equally difficult to interpret. The presence of a pericardial effusion, for example, may easily be mistaken for cardiac enlargement on a single roentgenogram, and frequently even extensive roentgenologic study short of angiocardiography will not enable one to differentiate between cardiac enlargement and such an effusion. However, the use of serial roentgen-ray examinations recording changes in cardiac size and shape in the same patient is extremely valid and usefuL Similarly, the single orthodiagraphic apparatus is useful for this purpose. With the knowledge that cardiac measurements are unreliable, the value of platitudes of anatomic locations of various cardiac chambers and contours of chambers has come under close scrutiny. Thus we have all been taught that enlargement of certain chambers of the heart presents a characteristic pattern with the location and relationship of the various cardiac chambers in the cadaver. Such analysis, however, leaves us in the unfortunate position of attempting to evaluate a facile, rapidly moving structure of which we have sampled only one movement in a roentgenogram of the living subject, and a fixed, immobile flabby organ in the cadaver. With the newer specialized methods of examination such as cardiac catheterization and angiocardiography we can examine these chambers and their relationship with one another and their contributions to the cardiac contour as a whole in each of their various physiologic phases. These in turn can be correlated with more simple studies using simple contrast media in the esophagus and examining the heart and lungs in various phases of respiration, in various positions and with varying amounts of stress. In short, all evaluations of cardiac size. shape and position must be examined in the light of physiologic alterations of the heart and great vessels, as well as altered physiology in the pulmonary circulation and ventilation of the lungs. With such comparisons, certain older concepts of cardiac contour and chamber enlargement remain valid in their interpretations, while others are found to be completely erroneous. A careful, painstaking roentgenographic study must include the fol-
Roentgenologic Aspects of Cardiac Disease
1577
lowing: a careful fluoroscopic examination plus technically perfect roentgenograms made in the posteroanterior projection in inspiration and in expiration, and lateral projections made with barium in the esophagus. In our experience these roentgenograms correlated with the fluoroscopic examination will almost always provide as much information, short of the specialized procedures mentioned above, as will more elaborate studies. We have not found the routine use of additional oblique roentgenograms of any added value except in a few selected instances, which can be decided upon at the time of fluoroscopy. During the fluoroscopic examination one can observe active physiologic changes in cardiac action with their reflection in the major vessels as well as their influence upon the adjacent trachea, major bronchi and esophagus. The examiner must study the heart as a whole, as well as each pulsating segment, and its relationship to the pulmonary vessels and aorta during the various phases of respiration. Quiet deep inspiration and expiration, as well as forced deep inspiration and expiration, Valsalva and Mueller maneuvers and hyperventilation in various projections must be included in this portion of the examination. The relationships between pulsations of all portions of the cardiac contour must be observed. By so doing one can occasionally differentiate the points at which ventricular and atrial contractions meet. With an obscure history of coronary artery disease the careful fluoroscopist can occasionally see the absence of ventricular contraction with resultant paradoxical pulsation of a portion of the cardiac wall representing the ischemic muscular segment. Finally the cardiac influence on the bariumfilled esophagus must be carefully observed. For this it is well to use both thick barium paste and thinner liquid barium. In the demonstration of pericardial effusion it is sometimes of value to include supine and prone fluoroscopy as well as roentgenograms in these positions, as an aid in determining the presence of such fluid. By comparing these studies with the special procedures of angiocardiography, selective angiocardiography, angiography and cardiac catheterization plus surgical exploration, certain concepts remain valid. SPECIFIC CHAMBER ENLARGEMENT
Righ t A trimll
It is extremely difficult to differentiate enlargement of this chamber specifically. Perhaps this is in part due to the relative infrequency of tricuspid valvular disease in the adult and to rare opportunity for such study. There are reports of forward displacement of the left atrium secondarily producing an increase in the prominence of the right cardiac border as due to a displacement of the right atrial appendage seen in the frontal projections, however, the determination of such enlargement even in the presence of congestive heart failure is uncertain at best.
1578
Roy R. Greening
Right Ventricle
The older established criteria for the determination of enlargement of this chamber seem to be upheld in the more recent studies. The right cardiac border may be prominent to the right of the spine with an increase in size of the area of the pulmonary outflow tract as seen in the posteroanterior projection. Fluoroscopically, the pulsations will be synchronous with those of the left ventricular area of the heart border. In the lateral projection the pulmonary outflow tract and the pulmonary artery form an arch just below the aortic arch and are superimposed upon the superior vena cava. With right ventricular enlargement this arch is widened and the normal air-filled space in the anterior mediastinum will be encroached upon. Similar enlargement can be demonstrated in the right anterior oblique projections. Occasionally a large left atrium in the presence of mitral stenosis will displace the right ventricle and add to the degree of displacement. In the diagnosis of this latter disease, however, one will be materially aided by the presence of large pulmonary vessels unless there is a marked pulmonary hypertension. In the presence of pulmonary stenosis this chamber mayor may not be enlarged. These changes have been well correlated with angiocardiographic studies and surgical reports using the examining finger in the left atrium as a guide.I. 2
Left AtriUIn Specific enlargement of this chamber occurs in the presence of mitral stenosis; hence most of the following remarks will apply specifically to this disease. The most reliable and earliest estimation of enlargement of this chamber can be made by noting an abruptly localized posterior displacement of the barium-filled esophagus just below the shadow of the bifurcation of the main stem bronchi as seen in the lateral roentgenogram. This is an earlier and a much more accurate sign of left atrial enlargement than is the reported obliteration of the infrabronchial space, since we have had much difficulty in finding this space in roentgenograms of the normal chest. Rarely, when there is marked enlargement of the left atrium, the esophagus is displaced posteriorly and to the left.3. 5 With a more marked enlargement of the left atrium the left main stem bronchus will be elevated; with further enlargement the carina is widened and elevated along with the pulmonary vessels. Finally there will be an appreciable narrowing of both main stem bronchi. In our experience the changes in both main stem bronchi have occurred much later in mitral stenosis than has the esophageal displacement described above, and in no instance of carinal widening have we failed to find esophageal displacement. More rarely there will be no displacement of either the esophagus or main stem bronchi, but the large left atrium
/loentgenologic Aspects of Cardiac Disease
1579
will present in the posteroinferior cardiac recess. When this happens, we have discovered the chamber enlargement only on the angiocardiogram. Left Ventricle
The specific determination of enlargement of this chamber in our experience is extremely difficult. When there is posterior displacement and obliteration of the posteroinferior cardiac recess, one can be fairly safe in estimating left ventricular enlargement; however, as we have already just seen, a large left atrium may occasionally obliterate this I3pace in the presence of an extreme degree of mitral stenosis. Pericardial effusions, peculiar diaphragmatic contours and large pericardial fat pads may all occasionally produce similar obliterations. The fiuoroscopic signs described, using the point of differential pulsations or the intracardiac notch as bounding the outlines of the left ventricle, are extremely difficult to determine and in our opinion have not proved to be reliable. Most recently, in the absence of specific outlinable enlargement of the other cardiac chambers, we have attempted to evaluate left ventricular size by correlating the lateral and posteroanterior roentgenograms and fluoroscopy and trying to develop a stereognostic sense of volumetric change in cardiac size. This has seemed to be the most accurate estimate of all, but is completely dependent upon the experience of the observer. SECONDARY ROENTGEN -RAY CHANGES IN CARDIAC DISEASE
There are a large number of secondary roentgen-ray changes visible upon technically perfect roentgenograms of the chest which are of inestimable aid in arriving at a diagnosis of any cardiac abnormality. Thus in examining any roentgenograms of the chest one must carefully examine the bony thorax. Certain myelosclerotic anemias, sickle cell disease, blood dyscrasias and even metastatic malignant disease will occasionally present themselves in a patient with symptoms suggesting some disorder of the cardiovascular system. Each of these lesions may produce alterations in the density and trabecular pattern of the bony thorax, so that we can quickly and readily exclude any cardiac pathology process as responsible for the primary cause of the symptoms. The presence of secondary rib erosion produced by enlargement of the intercostal arteries in coarctation of the aorta is almost a pathognomonic sign of this lesion, although there is also a typical elevation of the left border of the cardiac shadow in the way in which it blends with the shadow of the left leaf of the diaphragm. Also there is a small aortic knob and, most reliable of all, an indentation of the contour of the left side of the aorta as it descends along the spine, representing the site of the narrowed aortic segment. The status of the pulmonary vessels must be investigated both upon
1580
Roy R. Greening
the roentgenograms and especially during fluoroscopy. One must judge the amount of vascular engorgement present, as well as the presence or absence of and the volume and extent of pulsations of these vessels. By observing the pulmonary vascular changes with changes in intrathoracic pressure one can frequently anticipate the pressures in the pulmonary circulation and occasionally determine the presence of pulmonary hypertension. The degree of vascular engorgement in the major vessels as well as the smaller pulmonary vessels may be the earliest visible sign of congestive heart failure. These changes are particularly significant in a patient with an unexplained cough and dyspnea. The more obvious positive pulsations of the so-called hilar dance are familiar to everyone, but again may be seen in many lesions other than a patent ductus. Occasionally pulmonary arteriovenous aneurysms can be observed to change in size with changes in intrathoracic pressure. The variations in the major pulmonary vessels as well as in the smaller vessels are extremely important in etiologic determination and the evaluation of congenital heart lesions, but these changes are too extensive to attempt description here. The interested reader is referred to the works of Neuhauser, Whittenberg and Figley in this country and those of J6nsson and Kjellberg in Sweden. The alterations in the great vessels as they originate from the cardiac shadow must be observed and their influence upon the air-filled trachea and major bronchi as well as upon the barium-filled esophagus observed. By this means the detection of a right-sided aortic arch may be made easily, since there is almost a constant impression upon the air-filled trachea where this vessel crosses it. Similarly, the esophagus will be impressed at this point from the right side instead of from the left as it is with the normal left-sided aortic arch. This determination is particularly important if operation upon the heart is anticipated. Aberrant subclavian arteries, vascular rings and occasionally anomalous pulmonary veins and arteries may all produce indentations upon the adjacent structures such that their presence can usually be determined with accuracy without resorting to more dangerous and complicated studies of the cardiovascular system. CONGENITAL CARDIAC ABNORMALITIES
This subject is far too large and complex to more than mention here; there are certain principles which apply to roentgenologic methods in these lesions as well as in acquired heart disease. In these lesions one cannot use the position of various chambers as seen in the normal heart as a point of reference in evaluating the infant with congenital heart disease, for the unusual increase in the size of one of the chambers will often completely alter the entire axis of the heart. Hence the electrocardiogram and stethoscope must be used at the time of interpretation of the roentgenologic findings. Occasionally even with the aid of the
Roentgenologic Aspects of Cardiac Disease
1581
electrocardiogram it is difficult to determine the ehamber producing an abnormality of cardiae contour. The development of pulmonary hypertension in association with many congenital heart lesions will (:ompletely alter hoth the clinieal signs and the l"Oentgenologic findings in the individual as noted before its appearance. Hence espeeial attention must be paid to the pulmonary circulation. It is frequently impossible to establish an aeeurate diagnosis without the auxiliary aids of cardiac: eatheterization and angiocardiography. At present rapid strides are being made in the development of technical apparatus for more instantaneous sampling of passage of opaque media through the variolls eardiac chambers. It is now possible to make rapid serial roentgenograms of the opacified cardiac chambers in sequence or selectively, at the rate of six to twelve exposures a sewnd. By such means the entire field of cardiae disease is being continually subject to wider diagnostie interpretation. The most recent development in this field is the praetieal production of cineradiographic demonstration of the passage of opaque media through the cardiac and pulmonary ein:ulations. Whether these "moving pictures" will materially improve 0111' diagnostic acumen remains to be seen. HEFEHENCES 1. Dotter, C. T., and Steinberg, 1.: Angiocardiography. New York, Paul B. lIoeber, Inc., 1\)51. 2. Grishman, A., Sussman, lVI. L., awl Hkinberg, 1\1. F.: Angiocardiographic Analysis of Cardiac Configuration in Itheumatic Mitral Disease. Am. J. Roentgenol., 51: 33, ID44. 3. Roesler, H.: Clinical Roentgcnology of the Cardiovascular Hystem, 2nd cd. Springfield, 111., Charles C Thomas, 1\}43. 4. Roeslcr, I I.: Atlas of Cardioroentgellology. Springficld, Ill., Charles C Thomas, ID46. 5. Schwcdcl, J. B.: Clinical Roent g(:nology of the Heart. New York, I'aul B. Hocber, Inc., ID46. 6. Sosman, M. C.: Roentgenological Aspccts of Acquired Valvular lI(~arL DiHcasc. Am. J. Roentgenol., 42: 47, Hl3D.
3400 Sprucc Htreet Philadelphia 4, Pa.
roentgen-ray examination of the heart and great vessels is but a part of the complete examination of a patient with cardiac disease. Conclusions based upon roentgenographic findings alone should never be regarded as conclusive, nor should one roentgen-ray examination be compared with another or with the electrocardiogram or the clinical evaluation of the patient. Each is only a part of a complete examination in which it is necessary to collect all available information, weigh, evaluate and add each fragment so that it will fit in its proper place in arriving at a final correct conclusion. At times it is necessary to carry out specialized procedures such as cardiac catheterization, with pressure studies and oxygen saturation measurements, and complete or segmental angiocardiographic or angiographic studies. Each of these latter studies is a complete subject in itself, requiring special complicated apparatus and knowledge, such that here they can only be mentioned in passing. The roentgen-ray examination of the heart and great vessels is a projection of a complicated three-dimensional shadow on a one-dimensional plane and as such does not lend itself to easy evaluation. Evidence has been collected for many years in an attempt to draw anatomic conclusions about certain cardiac contours as demonstrated upon such roentgenograms made at a conventional6-foot tube-film distance. From these studies have originated such terms as "mitral configuration" and "aortic configuration." Each of these so-called classic contours may be found in at least ten different conditions, so that one must finally conclude that there is no special configuration of the cardiac shadow pathognomonic of a particular kind of cardiac disease. THE
From the Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia.
* Assistant Professor in Radiology, University of Pennsylvania Graduate School of Medicine and University Hospital; Consultant, Jeanes Hospital, Philadelphia, and Coatesville General Hospital. 1575
1576
Ray R. Greening
Similarly, the measurement of cardiac size by single roentgenographic methods as an indication of cardiac disease is no longer a completely valid procedure. The use of tables giving percentages of eardiac enlargement in the posteroanterior roentgenogram of the chest is fraught with many difficulties, only some of which can be easily reconciled. Thus a narrow thorax or a depression of the sternum will falsely indicate an enlargement of the cardiac shadow. Similarly, variations in respiration or the presence of pulmonary emphysema may occasionally produce a false impression of large cardiac size, or an impression of a very small cardiac shadow which may be confused with that due to a condition such as Addison's disease. Either of these cardiac sizes may be perfectly normaL Pathologically, the determination of cardiac size may be equally difficult to interpret. The presence of a pericardial effusion, for example, may easily be mistaken for cardiac enlargement on a single roentgenogram, and frequently even extensive roentgenologic study short of angiocardiography will not enable one to differentiate between cardiac enlargement and such an effusion. However, the use of serial roentgen-ray examinations recording changes in cardiac size and shape in the same patient is extremely valid and usefuL Similarly, the single orthodiagraphic apparatus is useful for this purpose. With the knowledge that cardiac measurements are unreliable, the value of platitudes of anatomic locations of various cardiac chambers and contours of chambers has come under close scrutiny. Thus we have all been taught that enlargement of certain chambers of the heart presents a characteristic pattern with the location and relationship of the various cardiac chambers in the cadaver. Such analysis, however, leaves us in the unfortunate position of attempting to evaluate a facile, rapidly moving structure of which we have sampled only one movement in a roentgenogram of the living subject, and a fixed, immobile flabby organ in the cadaver. With the newer specialized methods of examination such as cardiac catheterization and angiocardiography we can examine these chambers and their relationship with one another and their contributions to the cardiac contour as a whole in each of their various physiologic phases. These in turn can be correlated with more simple studies using simple contrast media in the esophagus and examining the heart and lungs in various phases of respiration, in various positions and with varying amounts of stress. In short, all evaluations of cardiac size. shape and position must be examined in the light of physiologic alterations of the heart and great vessels, as well as altered physiology in the pulmonary circulation and ventilation of the lungs. With such comparisons, certain older concepts of cardiac contour and chamber enlargement remain valid in their interpretations, while others are found to be completely erroneous. A careful, painstaking roentgenographic study must include the fol-
Roentgenologic Aspects of Cardiac Disease
1577
lowing: a careful fluoroscopic examination plus technically perfect roentgenograms made in the posteroanterior projection in inspiration and in expiration, and lateral projections made with barium in the esophagus. In our experience these roentgenograms correlated with the fluoroscopic examination will almost always provide as much information, short of the specialized procedures mentioned above, as will more elaborate studies. We have not found the routine use of additional oblique roentgenograms of any added value except in a few selected instances, which can be decided upon at the time of fluoroscopy. During the fluoroscopic examination one can observe active physiologic changes in cardiac action with their reflection in the major vessels as well as their influence upon the adjacent trachea, major bronchi and esophagus. The examiner must study the heart as a whole, as well as each pulsating segment, and its relationship to the pulmonary vessels and aorta during the various phases of respiration. Quiet deep inspiration and expiration, as well as forced deep inspiration and expiration, Valsalva and Mueller maneuvers and hyperventilation in various projections must be included in this portion of the examination. The relationships between pulsations of all portions of the cardiac contour must be observed. By so doing one can occasionally differentiate the points at which ventricular and atrial contractions meet. With an obscure history of coronary artery disease the careful fluoroscopist can occasionally see the absence of ventricular contraction with resultant paradoxical pulsation of a portion of the cardiac wall representing the ischemic muscular segment. Finally the cardiac influence on the bariumfilled esophagus must be carefully observed. For this it is well to use both thick barium paste and thinner liquid barium. In the demonstration of pericardial effusion it is sometimes of value to include supine and prone fluoroscopy as well as roentgenograms in these positions, as an aid in determining the presence of such fluid. By comparing these studies with the special procedures of angiocardiography, selective angiocardiography, angiography and cardiac catheterization plus surgical exploration, certain concepts remain valid. SPECIFIC CHAMBER ENLARGEMENT
Righ t A trimll
It is extremely difficult to differentiate enlargement of this chamber specifically. Perhaps this is in part due to the relative infrequency of tricuspid valvular disease in the adult and to rare opportunity for such study. There are reports of forward displacement of the left atrium secondarily producing an increase in the prominence of the right cardiac border as due to a displacement of the right atrial appendage seen in the frontal projections, however, the determination of such enlargement even in the presence of congestive heart failure is uncertain at best.
1578
Roy R. Greening
Right Ventricle
The older established criteria for the determination of enlargement of this chamber seem to be upheld in the more recent studies. The right cardiac border may be prominent to the right of the spine with an increase in size of the area of the pulmonary outflow tract as seen in the posteroanterior projection. Fluoroscopically, the pulsations will be synchronous with those of the left ventricular area of the heart border. In the lateral projection the pulmonary outflow tract and the pulmonary artery form an arch just below the aortic arch and are superimposed upon the superior vena cava. With right ventricular enlargement this arch is widened and the normal air-filled space in the anterior mediastinum will be encroached upon. Similar enlargement can be demonstrated in the right anterior oblique projections. Occasionally a large left atrium in the presence of mitral stenosis will displace the right ventricle and add to the degree of displacement. In the diagnosis of this latter disease, however, one will be materially aided by the presence of large pulmonary vessels unless there is a marked pulmonary hypertension. In the presence of pulmonary stenosis this chamber mayor may not be enlarged. These changes have been well correlated with angiocardiographic studies and surgical reports using the examining finger in the left atrium as a guide.I. 2
Left AtriUIn Specific enlargement of this chamber occurs in the presence of mitral stenosis; hence most of the following remarks will apply specifically to this disease. The most reliable and earliest estimation of enlargement of this chamber can be made by noting an abruptly localized posterior displacement of the barium-filled esophagus just below the shadow of the bifurcation of the main stem bronchi as seen in the lateral roentgenogram. This is an earlier and a much more accurate sign of left atrial enlargement than is the reported obliteration of the infrabronchial space, since we have had much difficulty in finding this space in roentgenograms of the normal chest. Rarely, when there is marked enlargement of the left atrium, the esophagus is displaced posteriorly and to the left.3. 5 With a more marked enlargement of the left atrium the left main stem bronchus will be elevated; with further enlargement the carina is widened and elevated along with the pulmonary vessels. Finally there will be an appreciable narrowing of both main stem bronchi. In our experience the changes in both main stem bronchi have occurred much later in mitral stenosis than has the esophageal displacement described above, and in no instance of carinal widening have we failed to find esophageal displacement. More rarely there will be no displacement of either the esophagus or main stem bronchi, but the large left atrium
/loentgenologic Aspects of Cardiac Disease
1579
will present in the posteroinferior cardiac recess. When this happens, we have discovered the chamber enlargement only on the angiocardiogram. Left Ventricle
The specific determination of enlargement of this chamber in our experience is extremely difficult. When there is posterior displacement and obliteration of the posteroinferior cardiac recess, one can be fairly safe in estimating left ventricular enlargement; however, as we have already just seen, a large left atrium may occasionally obliterate this I3pace in the presence of an extreme degree of mitral stenosis. Pericardial effusions, peculiar diaphragmatic contours and large pericardial fat pads may all occasionally produce similar obliterations. The fiuoroscopic signs described, using the point of differential pulsations or the intracardiac notch as bounding the outlines of the left ventricle, are extremely difficult to determine and in our opinion have not proved to be reliable. Most recently, in the absence of specific outlinable enlargement of the other cardiac chambers, we have attempted to evaluate left ventricular size by correlating the lateral and posteroanterior roentgenograms and fluoroscopy and trying to develop a stereognostic sense of volumetric change in cardiac size. This has seemed to be the most accurate estimate of all, but is completely dependent upon the experience of the observer. SECONDARY ROENTGEN -RAY CHANGES IN CARDIAC DISEASE
There are a large number of secondary roentgen-ray changes visible upon technically perfect roentgenograms of the chest which are of inestimable aid in arriving at a diagnosis of any cardiac abnormality. Thus in examining any roentgenograms of the chest one must carefully examine the bony thorax. Certain myelosclerotic anemias, sickle cell disease, blood dyscrasias and even metastatic malignant disease will occasionally present themselves in a patient with symptoms suggesting some disorder of the cardiovascular system. Each of these lesions may produce alterations in the density and trabecular pattern of the bony thorax, so that we can quickly and readily exclude any cardiac pathology process as responsible for the primary cause of the symptoms. The presence of secondary rib erosion produced by enlargement of the intercostal arteries in coarctation of the aorta is almost a pathognomonic sign of this lesion, although there is also a typical elevation of the left border of the cardiac shadow in the way in which it blends with the shadow of the left leaf of the diaphragm. Also there is a small aortic knob and, most reliable of all, an indentation of the contour of the left side of the aorta as it descends along the spine, representing the site of the narrowed aortic segment. The status of the pulmonary vessels must be investigated both upon
1580
Roy R. Greening
the roentgenograms and especially during fluoroscopy. One must judge the amount of vascular engorgement present, as well as the presence or absence of and the volume and extent of pulsations of these vessels. By observing the pulmonary vascular changes with changes in intrathoracic pressure one can frequently anticipate the pressures in the pulmonary circulation and occasionally determine the presence of pulmonary hypertension. The degree of vascular engorgement in the major vessels as well as the smaller pulmonary vessels may be the earliest visible sign of congestive heart failure. These changes are particularly significant in a patient with an unexplained cough and dyspnea. The more obvious positive pulsations of the so-called hilar dance are familiar to everyone, but again may be seen in many lesions other than a patent ductus. Occasionally pulmonary arteriovenous aneurysms can be observed to change in size with changes in intrathoracic pressure. The variations in the major pulmonary vessels as well as in the smaller vessels are extremely important in etiologic determination and the evaluation of congenital heart lesions, but these changes are too extensive to attempt description here. The interested reader is referred to the works of Neuhauser, Whittenberg and Figley in this country and those of J6nsson and Kjellberg in Sweden. The alterations in the great vessels as they originate from the cardiac shadow must be observed and their influence upon the air-filled trachea and major bronchi as well as upon the barium-filled esophagus observed. By this means the detection of a right-sided aortic arch may be made easily, since there is almost a constant impression upon the air-filled trachea where this vessel crosses it. Similarly, the esophagus will be impressed at this point from the right side instead of from the left as it is with the normal left-sided aortic arch. This determination is particularly important if operation upon the heart is anticipated. Aberrant subclavian arteries, vascular rings and occasionally anomalous pulmonary veins and arteries may all produce indentations upon the adjacent structures such that their presence can usually be determined with accuracy without resorting to more dangerous and complicated studies of the cardiovascular system. CONGENITAL CARDIAC ABNORMALITIES
This subject is far too large and complex to more than mention here; there are certain principles which apply to roentgenologic methods in these lesions as well as in acquired heart disease. In these lesions one cannot use the position of various chambers as seen in the normal heart as a point of reference in evaluating the infant with congenital heart disease, for the unusual increase in the size of one of the chambers will often completely alter the entire axis of the heart. Hence the electrocardiogram and stethoscope must be used at the time of interpretation of the roentgenologic findings. Occasionally even with the aid of the
Roentgenologic Aspects of Cardiac Disease
1581
electrocardiogram it is difficult to determine the ehamber producing an abnormality of cardiae contour. The development of pulmonary hypertension in association with many congenital heart lesions will (:ompletely alter hoth the clinieal signs and the l"Oentgenologic findings in the individual as noted before its appearance. Hence espeeial attention must be paid to the pulmonary circulation. It is frequently impossible to establish an aeeurate diagnosis without the auxiliary aids of cardiac: eatheterization and angiocardiography. At present rapid strides are being made in the development of technical apparatus for more instantaneous sampling of passage of opaque media through the variolls eardiac chambers. It is now possible to make rapid serial roentgenograms of the opacified cardiac chambers in sequence or selectively, at the rate of six to twelve exposures a sewnd. By such means the entire field of cardiae disease is being continually subject to wider diagnostie interpretation. The most recent development in this field is the praetieal production of cineradiographic demonstration of the passage of opaque media through the cardiac and pulmonary ein:ulations. Whether these "moving pictures" will materially improve 0111' diagnostic acumen remains to be seen. HEFEHENCES 1. Dotter, C. T., and Steinberg, 1.: Angiocardiography. New York, Paul B. lIoeber, Inc., 1\)51. 2. Grishman, A., Sussman, lVI. L., awl Hkinberg, 1\1. F.: Angiocardiographic Analysis of Cardiac Configuration in Itheumatic Mitral Disease. Am. J. Roentgenol., 51: 33, ID44. 3. Roesler, H.: Clinical Roentgcnology of the Cardiovascular Hystem, 2nd cd. Springfield, 111., Charles C Thomas, 1\}43. 4. Roeslcr, I I.: Atlas of Cardioroentgellology. Springficld, Ill., Charles C Thomas, ID46. 5. Schwcdcl, J. B.: Clinical Roent g(:nology of the Heart. New York, I'aul B. Hocber, Inc., ID46. 6. Sosman, M. C.: Roentgenological Aspccts of Acquired Valvular lI(~arL DiHcasc. Am. J. Roentgenol., 42: 47, Hl3D.
3400 Sprucc Htreet Philadelphia 4, Pa.