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Echocardiographic Differentiation of Mediastinal Tumors from Primary Cardiac Disease
REFERENCES
Yurick BS, Ottoman RE: Primary mediastinal choriocarcinoma. Radiology 75:901-907, 1960 2 Fine G, Smith RW Jr, Pachter MR: Primary extragenital choriocarcinoma in the male subject. Case report and review of the literature. Am J Med 32:776-794, 1962 3 Wenger ME, Dines DE, Ahmann DL, et al: Primary mediastinal choriocarcinoma. Mayo Clin Proc 43:570-575, 1968 4 Fanger H, MacAndrew R: Extragenital chorionepithelioma in female arising from mediastinal teratoma. RI Med J 35:259-260, 1952 5 Lynch MJG, Blewett GL: Choriocarcinoma arising in male mediastinum. Thorax 8:157-161, 1953 6 Erdmann ]F, Brown HA, Shaw HW (Cited by Ottoman and Yurick, 1960). 7 Bennington JL, Haber SL, Schweid A: Primary mediastinal choriocarcinoma. Dis Chest 46:623-626, 1964 8 Holt LP, Melcher DH, Colquhoun J: Extra-gonadal choriocarcinoma in the male. Postgrad Med J 41:134-138, 1965 9 Primary mediastinal choriocarcinoma (lead article). Br Med J 135, 1969 10 Marchand F: Uber die so generation decidualin geschwillste in Anschluss and Normale Geburt, abort, blasen mole and extraule Minschwangerschaft. Monatsch Geburtsh Gynak 1:419, 515, 1895 11 Schlagenhanfer F: Uber das Vorkommen chorionepithliom und trangenmolenartiger Wucherungen in Teratomen. Wien Klin Wschr 15:571, 604, 1902 12 Miller ], Browne FJ: Extragenital chorionepithelioma of congenital origin. J Obstet Gynaec 29:48, 1922 13 Arey LB: Developmental Anatomy: A Textbook and Laboratory Manual of Embryology. Philadelphia, W.B. Saunders, 1946 14 Patten BM: Human Embryology (chap. 8). New York, Blakiston Company, 1946 15 Friedman NB: Comparative morphogenesis of extragenital and gonadal teratoid tumours. Cancer 4:265-276, 1951 16 Prusty S, Bhayana ], Wayak NC, et al: Primary mediastinal choriocarcinoma. Dis Chest 56:543-546, 1969 17 Frank RT: Discussion. Arch Path 13:187, 1932 18 Ewing J: Neoplastic Disease. Philadelphia, W.B. Saunders, 1940, p 1047 19 Magovem GJ, Blades B: Primary extragenital chorioepithelioma in the male mediastinum. J Thorac Cardiovasc Surg 35:378-383, 1958 20 Goldstein DP, Piro AN: Combined chemotherapy in the treatment .of germ cell tumours containing choriocarcinoma in males and females. Surg Gynecol Obstet 134:61, 1972
108 CHILD, ABBASI, PEARCE
Echocardiographic Differentiation of Mediastinal Tumors from Primary Cardiac Disease* John S. Child, M.D., Abdul S. Abbasi, M.D., and Morton Lee Pearce, M.D.
Three cases of mediastinal tumors (thymic cyst, fibrosarcoma, fibrotipoma) mimicking primary cardiac disease were studied by echocardiography. The echocardiographic findings of the thymic cyst are presented and the echocardiograms in the other two patients discussed. Intrinsic cardiac pathology was excluded and discovery of abnormal extracardiac echoes prompted further investigation. In each instance, the echocardiographic interpretation of the nature and position of each extracardiac mass was confirmed by surgery or autopsy. We conclude that echocardiography is a useful noninvasive technique in differentiating between cardiac and extracardiac disease, and should be performed whenever an unusual or enlarged cardiac silhouette is encountered.
E
chocardiography has been useful in the noninvasive diagnosis of a variety of cardiac abnormalities including intracardiac tumors, in particular atrial myxomas.'- 5 A variety of mediastinal tumors presenting as cardiovascular disorders have been reported, 6 - 12 which required various invasive procedures for their diagnosis. We present three patients with mediastinal tumors simulating primary intrinsic cardiac disease in whom echocardiography was useful in excluding cardiac pathology and in suggesting extracardiac pathology in close proximity to the heart. METIIOD
The echocardiograms were recorded with commercially available equipment. A 2.25 MHZ 10 em focussed transducer with 0.5 em diameter, and a repetition rate of 1000 pulses per second was utilized. The echocardiograms were recorded on a strip chart in one, and on polaroid film in the other two patients. By using a conventional technique,la the transducer was placed in the fourth or fifth intercostal space at the left sternal border except in one patient in whom the third intercostal space was more helpful for recording mediastinal echoes. The different cardiac structures were identified by scanning the ultrasound beam from the cardiac base toward the apex. The transducer was first pointed anteroposteriorly and slightly medially to identify the mitral valve. The transducer was then directed laterally and inferiorly to record simultaneously echoes from the posterior left ventricular wall and the interventricular septum. The near gain was reduced in an attempt to record the anterior right ventricular wall. °From the Department of Medicine, UCLA Hospital and Wadsworth Veterans Administration Hospital, Los Angeles. Supported in part by AHA Greater Los Angeles Affiliate Award No. 490-1 G I. Reprint requests: Dr. Child, Division of Cardiology, UC Center for Health Sciences, Los Angeles 90024
CHEST, 67: 1, JANUARY, 1975
PATIENT DESCRIPTION
A i 4-year-old man was admitted for evaluation of a "vague bulge" in the left midlateral cardiac border on routine chest film. He was asymptomatic and physical examination revealed only a long thin chest wall with mild pectus excavahun. An electrocardiogram was normal. An echocardiogram revealed a double-walled anterior structure moving toward the anterior chest wall in systole (Fig 1). No solid echoes appeared between these walls even at high gain settings. The right ventricular wall was not identified with certainty and the double-walled stmcture (presumed cyst) appeared contiguous with the right ventricular wall. On sweeping toward the aortic root, the posterior wall of this double-walled echo was anterior to the aortic wall ( Fig 2). The echogram was otherwise normal. The interventricular septum appeared to move paradoxically. However, scanning revealed that we were near the aortic root, a position in which a normal septum may move paradoxically. The sephun moved normally when the transducer was directed laterally and just below the plane of the mitral valve. Results of right heart catheterization including angiography was normal. Thoracic !aminograms suggested an anterior mediastinal struch1re overlying the right ventricular outflow tract, the right atrium, and the anterior aspect of the left ventricle. At thoracotomy an anterior mediastinal thymic cyst was excised. The patient was lost to follow-up and a postoperative echocardiogram could not be performed. DISCUSSION
Three patients who presented with cardiac symptoms or an abnormal heart shadow were discovered to have unusual echoes in close proximity to the heart. Subse-
wall
I .Y . Septum
FIGURE 1. Echocardiogram of the thymic cyst. Note the double-walled struch1re, with a relatively echo-free space between its walls, sihtated anterior to the IV septum. The right ventricular cavity is not clearly identifiable. ECG=electrocardiogram; IV septum= interventricular septum; MV=mitral valve; Post LV= posterior left ventricular wall.
CHEST, 67: 1, JANUARY, 1975
FIGURE 2. Echocardiogram of patient No. l. The transducer is directed toward the aortic root ( Ao) and the cyst wall ( marked by arrow ) is seen anterior to th e aortic root. The left atrium ( LA) is posterior to the aortic root. ( Figures 1 and 2 were selected from a continuous sweep ) . quent pathologic confirmation of extracardiac tumors was obtained in all. As described above, our first patient was extremely interesting and the echocardiogram revealed an unusual anterior wall echo which was initially suspected to be aneurysmal dilatation of either the right ventricular outflow tract or pulmonary artery. The possibility of a cystic structure being displaced by the great vessels during systole was considered. Angiography excluded an abnormality of the pulmonary artery and of the right ventricle and surgery confirmed a thymic cyst. Although no previous M-mode echocardiographic report on mediastinal tumors is available, A-mode studies 14 • 15 and, B-scanning studies 15 • 1 7 suggest that differentiation of solid from cystic tumors is facilitated by a change in gain settings. At high gain, the solid tumors will "fill-in" with echoes, whereas .a cystic structure will not. This has been termed "sonolucency," and was seen in this patient. It is unfortunate tha t a postoperative echocardiogram could not be done. Although not done, injection of indocyanine green dye or saline solution into the right ventricle during echocardiography would have assisted in id entification of the right ventricle and the overlying cyst. We subsequently studied two other patients with mediastinal tumors b y echocardiography. Our second patient, who had a recurrent liposarcoma with retrocardiac extension, was clinically suspected of having restricted cardiac filling due to myocardial or pericardia! infiltration . He was critically ill and restless and performance of the echocardiogram was technically difficult. However, the echocardiogram revealed a wide strong echo, posterior to the posterior left ventricular wall,
ECHOCARDIOGRAPHIC DIFFERENTIATION OF MEDIASTINAL TUMORS 109
thought to be the tumor wall. No obvious echographic evidence of primary cardiac disease was seen, but the diminished anterior mitral valve diastolic closure rate was consistent with impaired left atrial emptying. This may be seen with decreased left ventricular compliance. 1 "·20 The postmortem findings confirmed the echocardiographic interpretation by revealing a extracardiac mass. An additional explanation for the restrictive picture may have been due to vena cava compression by tumor, which resulted in decreased venous return and diminished ventricular filling. Our third patient had an echocardiogram performed for evaluation of cardiac enlargement thought to be due to pericardia! disease 1 R· 19 or myocardiopathy. 13 • 20 - 2 2 Because of her marked obesity, the echocardiogram was technically difficult but was of sufficient clarity to allow recognition of an unusual strong echo behind the posterior left ventricular wall, apparently extracardiac in origin, instead of the lung tissue normally seen in this area. When the prominent echo behind the heart was seen and no primary cardiac disease was discovered, further study retrospectively of the chest x-ray films disclosed the posterior mediastinal mass, which was found to be a fibrolipoma at surgery. Whether the mass caused the patient's symptoms of shortness of breath by cardiac compression is questionable.
Circulation 46:897-904, 1972 14 Ostrum BJ, Goldberg BB, Isard HJ: A-mode ultrasound differentiation of soft-tissue masses. Radiology 88:745749, 1967 15 Blum M, Goldman AB, Herskovic A, et al: Clinical applications of thyroid echography. N Eng! J Med 287: ll64-1169, 1972 16 Freimanis AK, Asher WM: Echographic study of abdominal lesions. Am J Roentgen 108:747-755, 1970 17 McDonald DC, Leopold GR: Ultrasound B-scanning in the differentiation of Baker's cyst and thrombophlebitis. Br J Radiol45:729-732, 1972 18 Feigenbaum H: Echocardiographic diagnosis of pericardia! effusion. Am J Cardiol26:475-479, 1970 19 Abbasi AS, Flynn JM: The use of modified echocardiographic M-scan technique in the diagnosis of pericardia! effusion. Proceedings of the Scientific Sessions of the American Institute of Ultrasound in Medicine, Philadelphia, October 1972 20 Shah PM, Gramiak R, Kramer DH: Ultrasound localiza·· tion of left ventricular outflow obstruction in hypertrophic obstructive myocardiopathy. Circulation 40:3-11, 1969 21 Abbasi AS, Chahine RA, MacAipin RN, eta!: Ultrasound in the diagnosis of primary congestive cardiomyopathy. Chest 63:937-942, 1973 22 Abbasi AS, MacAlpin RN, Eber LM, eta!: Left ventricular hypertrophy diagnosed by echocardiography. N Eng) J Med 289:118-121, 1973
REFERENCES
1 Schattenberg TT: Echocardiographic diagnosis of left atrial myxoma. Mayo Clin Proc 43:620-627, 1968 2 Wolfe SB, Popp RL, Feigenbaum H: Diagnosis of atrial tumors by ultrasound. Circulation 39:615-622, 1969 3 Popp RL, Harrison DC: Ultrasound for the diagnosis of atrial tumor. Ann Intern Med 71:785-787, 1969 4 Finegan RE, Harrison DC: Diagnosis of left atrial myxoma by echocardiography. N Eng] J Med 282:10221023, 1970 5 Kostis JB, Moghadam AN: Echocardiographic diagnosis of left atrial myxoma. Chest 58:550-552, 1970 6 Allee G, Logue B, Mansour K: Thymic cyst simulating multiple cardiovascular abnormalities and presenting with pericarditis and pericardia! tamponade. Am J Cardiol 31:377-380, 1973 7 Coulshed N, Jones EW, Temple LJ: Cyst of the thymus: report of a case presenting as idiopathic cardiomegaly. Br J Radio! 31:95-99, 1958 8 Podolsky S, Ehrlich EW, Howard JM: Congenital thymic cyst attached to the pericardium. Dis Chest 42:642-644, 1962 9 Schlurger J, Scarpa WJ, Rosenblum DJ, et al: Thymic cyst simulating massive cardiomegaly. Report of a case and review of the literature. Dis Chest 53:365-368, 1968 10 Oldham HN, Sahiston DC: Primary tumors and cysts of the mediastinum presenting as cardiovascular abnormalities. Arch Surg (Chicago) 96:71-75, 1968 11 Shaver VC, Bailey WR, Marrangoni AG: Acquired pulmonic stenosis due to external cardiac compression. Am J Cardiol 16:256-261, 1965 12 Seltzer ItA, Mills DS, Baddocl;: SS. et al: ~fediastinal . thymic cyst. Dis Chest 53:186-196, 1968 .. 13 Abbasi AS, }.lacAipin R};, Eber LM, et al: Echocardiographic diagnosb of idiopathic hypertrophic cardiomyopathy without left ventricular outflow obstruction.
A Simplified Method for Measuring Helium Closing Volume* Kirk McClelland 00 and Charles Mittman, M.D., F.C.C.P.t
A simple method for delivering a constant volume of helium for the measurement of airway closing volume is described. Using a standard fiveway valve and PVC plastic irrigation pipe, a device was constructed which permits the delivery of a uniform volume of helium and avoids the troublesome valve change during inspiration. Results obtained when using this device were comparable to those with the use of a conventional bag to contain the he6um.
T
he measurement of the volume at which small airways in dependent lung zones cease to ventilate (closing volume) has been proposed as a valuable means to detect early disease. Numerous investigators'- 3 use a technique similar to that first reported by Dollfuss and co-workers. • A subject first exhales to residual volume and then inhales slowly to total lung capacity. The initial portion of the inspiration consists of a bolus of some
°From the Respiratory Disease Department, City of Hope Medical Center, Duarte, Ca. ••supervisor, Pulmonary Physiology Laboratory. tJ)ire~r, Department of ltespiratory Piseases . This work was supported' by grants from the National Heart and Lung lnstitute ( l{El2833) and tlte ~ouncil for Tobacco Research. ·· Reprint requests: Mr. McClelland, City of Hope Medical Center, Dtwrte~ California fHOIO ~I:I~ST,
67: 1,
JA~YAij¥,
1975
Yurick BS, Ottoman RE: Primary mediastinal choriocarcinoma. Radiology 75:901-907, 1960 2 Fine G, Smith RW Jr, Pachter MR: Primary extragenital choriocarcinoma in the male subject. Case report and review of the literature. Am J Med 32:776-794, 1962 3 Wenger ME, Dines DE, Ahmann DL, et al: Primary mediastinal choriocarcinoma. Mayo Clin Proc 43:570-575, 1968 4 Fanger H, MacAndrew R: Extragenital chorionepithelioma in female arising from mediastinal teratoma. RI Med J 35:259-260, 1952 5 Lynch MJG, Blewett GL: Choriocarcinoma arising in male mediastinum. Thorax 8:157-161, 1953 6 Erdmann ]F, Brown HA, Shaw HW (Cited by Ottoman and Yurick, 1960). 7 Bennington JL, Haber SL, Schweid A: Primary mediastinal choriocarcinoma. Dis Chest 46:623-626, 1964 8 Holt LP, Melcher DH, Colquhoun J: Extra-gonadal choriocarcinoma in the male. Postgrad Med J 41:134-138, 1965 9 Primary mediastinal choriocarcinoma (lead article). Br Med J 135, 1969 10 Marchand F: Uber die so generation decidualin geschwillste in Anschluss and Normale Geburt, abort, blasen mole and extraule Minschwangerschaft. Monatsch Geburtsh Gynak 1:419, 515, 1895 11 Schlagenhanfer F: Uber das Vorkommen chorionepithliom und trangenmolenartiger Wucherungen in Teratomen. Wien Klin Wschr 15:571, 604, 1902 12 Miller ], Browne FJ: Extragenital chorionepithelioma of congenital origin. J Obstet Gynaec 29:48, 1922 13 Arey LB: Developmental Anatomy: A Textbook and Laboratory Manual of Embryology. Philadelphia, W.B. Saunders, 1946 14 Patten BM: Human Embryology (chap. 8). New York, Blakiston Company, 1946 15 Friedman NB: Comparative morphogenesis of extragenital and gonadal teratoid tumours. Cancer 4:265-276, 1951 16 Prusty S, Bhayana ], Wayak NC, et al: Primary mediastinal choriocarcinoma. Dis Chest 56:543-546, 1969 17 Frank RT: Discussion. Arch Path 13:187, 1932 18 Ewing J: Neoplastic Disease. Philadelphia, W.B. Saunders, 1940, p 1047 19 Magovem GJ, Blades B: Primary extragenital chorioepithelioma in the male mediastinum. J Thorac Cardiovasc Surg 35:378-383, 1958 20 Goldstein DP, Piro AN: Combined chemotherapy in the treatment .of germ cell tumours containing choriocarcinoma in males and females. Surg Gynecol Obstet 134:61, 1972
108 CHILD, ABBASI, PEARCE
Echocardiographic Differentiation of Mediastinal Tumors from Primary Cardiac Disease* John S. Child, M.D., Abdul S. Abbasi, M.D., and Morton Lee Pearce, M.D.
Three cases of mediastinal tumors (thymic cyst, fibrosarcoma, fibrotipoma) mimicking primary cardiac disease were studied by echocardiography. The echocardiographic findings of the thymic cyst are presented and the echocardiograms in the other two patients discussed. Intrinsic cardiac pathology was excluded and discovery of abnormal extracardiac echoes prompted further investigation. In each instance, the echocardiographic interpretation of the nature and position of each extracardiac mass was confirmed by surgery or autopsy. We conclude that echocardiography is a useful noninvasive technique in differentiating between cardiac and extracardiac disease, and should be performed whenever an unusual or enlarged cardiac silhouette is encountered.
E
chocardiography has been useful in the noninvasive diagnosis of a variety of cardiac abnormalities including intracardiac tumors, in particular atrial myxomas.'- 5 A variety of mediastinal tumors presenting as cardiovascular disorders have been reported, 6 - 12 which required various invasive procedures for their diagnosis. We present three patients with mediastinal tumors simulating primary intrinsic cardiac disease in whom echocardiography was useful in excluding cardiac pathology and in suggesting extracardiac pathology in close proximity to the heart. METIIOD
The echocardiograms were recorded with commercially available equipment. A 2.25 MHZ 10 em focussed transducer with 0.5 em diameter, and a repetition rate of 1000 pulses per second was utilized. The echocardiograms were recorded on a strip chart in one, and on polaroid film in the other two patients. By using a conventional technique,la the transducer was placed in the fourth or fifth intercostal space at the left sternal border except in one patient in whom the third intercostal space was more helpful for recording mediastinal echoes. The different cardiac structures were identified by scanning the ultrasound beam from the cardiac base toward the apex. The transducer was first pointed anteroposteriorly and slightly medially to identify the mitral valve. The transducer was then directed laterally and inferiorly to record simultaneously echoes from the posterior left ventricular wall and the interventricular septum. The near gain was reduced in an attempt to record the anterior right ventricular wall. °From the Department of Medicine, UCLA Hospital and Wadsworth Veterans Administration Hospital, Los Angeles. Supported in part by AHA Greater Los Angeles Affiliate Award No. 490-1 G I. Reprint requests: Dr. Child, Division of Cardiology, UC Center for Health Sciences, Los Angeles 90024
CHEST, 67: 1, JANUARY, 1975
PATIENT DESCRIPTION
A i 4-year-old man was admitted for evaluation of a "vague bulge" in the left midlateral cardiac border on routine chest film. He was asymptomatic and physical examination revealed only a long thin chest wall with mild pectus excavahun. An electrocardiogram was normal. An echocardiogram revealed a double-walled anterior structure moving toward the anterior chest wall in systole (Fig 1). No solid echoes appeared between these walls even at high gain settings. The right ventricular wall was not identified with certainty and the double-walled stmcture (presumed cyst) appeared contiguous with the right ventricular wall. On sweeping toward the aortic root, the posterior wall of this double-walled echo was anterior to the aortic wall ( Fig 2). The echogram was otherwise normal. The interventricular septum appeared to move paradoxically. However, scanning revealed that we were near the aortic root, a position in which a normal septum may move paradoxically. The sephun moved normally when the transducer was directed laterally and just below the plane of the mitral valve. Results of right heart catheterization including angiography was normal. Thoracic !aminograms suggested an anterior mediastinal struch1re overlying the right ventricular outflow tract, the right atrium, and the anterior aspect of the left ventricle. At thoracotomy an anterior mediastinal thymic cyst was excised. The patient was lost to follow-up and a postoperative echocardiogram could not be performed. DISCUSSION
Three patients who presented with cardiac symptoms or an abnormal heart shadow were discovered to have unusual echoes in close proximity to the heart. Subse-
wall
I .Y . Septum
FIGURE 1. Echocardiogram of the thymic cyst. Note the double-walled struch1re, with a relatively echo-free space between its walls, sihtated anterior to the IV septum. The right ventricular cavity is not clearly identifiable. ECG=electrocardiogram; IV septum= interventricular septum; MV=mitral valve; Post LV= posterior left ventricular wall.
CHEST, 67: 1, JANUARY, 1975
FIGURE 2. Echocardiogram of patient No. l. The transducer is directed toward the aortic root ( Ao) and the cyst wall ( marked by arrow ) is seen anterior to th e aortic root. The left atrium ( LA) is posterior to the aortic root. ( Figures 1 and 2 were selected from a continuous sweep ) . quent pathologic confirmation of extracardiac tumors was obtained in all. As described above, our first patient was extremely interesting and the echocardiogram revealed an unusual anterior wall echo which was initially suspected to be aneurysmal dilatation of either the right ventricular outflow tract or pulmonary artery. The possibility of a cystic structure being displaced by the great vessels during systole was considered. Angiography excluded an abnormality of the pulmonary artery and of the right ventricle and surgery confirmed a thymic cyst. Although no previous M-mode echocardiographic report on mediastinal tumors is available, A-mode studies 14 • 15 and, B-scanning studies 15 • 1 7 suggest that differentiation of solid from cystic tumors is facilitated by a change in gain settings. At high gain, the solid tumors will "fill-in" with echoes, whereas .a cystic structure will not. This has been termed "sonolucency," and was seen in this patient. It is unfortunate tha t a postoperative echocardiogram could not be done. Although not done, injection of indocyanine green dye or saline solution into the right ventricle during echocardiography would have assisted in id entification of the right ventricle and the overlying cyst. We subsequently studied two other patients with mediastinal tumors b y echocardiography. Our second patient, who had a recurrent liposarcoma with retrocardiac extension, was clinically suspected of having restricted cardiac filling due to myocardial or pericardia! infiltration . He was critically ill and restless and performance of the echocardiogram was technically difficult. However, the echocardiogram revealed a wide strong echo, posterior to the posterior left ventricular wall,
ECHOCARDIOGRAPHIC DIFFERENTIATION OF MEDIASTINAL TUMORS 109
thought to be the tumor wall. No obvious echographic evidence of primary cardiac disease was seen, but the diminished anterior mitral valve diastolic closure rate was consistent with impaired left atrial emptying. This may be seen with decreased left ventricular compliance. 1 "·20 The postmortem findings confirmed the echocardiographic interpretation by revealing a extracardiac mass. An additional explanation for the restrictive picture may have been due to vena cava compression by tumor, which resulted in decreased venous return and diminished ventricular filling. Our third patient had an echocardiogram performed for evaluation of cardiac enlargement thought to be due to pericardia! disease 1 R· 19 or myocardiopathy. 13 • 20 - 2 2 Because of her marked obesity, the echocardiogram was technically difficult but was of sufficient clarity to allow recognition of an unusual strong echo behind the posterior left ventricular wall, apparently extracardiac in origin, instead of the lung tissue normally seen in this area. When the prominent echo behind the heart was seen and no primary cardiac disease was discovered, further study retrospectively of the chest x-ray films disclosed the posterior mediastinal mass, which was found to be a fibrolipoma at surgery. Whether the mass caused the patient's symptoms of shortness of breath by cardiac compression is questionable.
Circulation 46:897-904, 1972 14 Ostrum BJ, Goldberg BB, Isard HJ: A-mode ultrasound differentiation of soft-tissue masses. Radiology 88:745749, 1967 15 Blum M, Goldman AB, Herskovic A, et al: Clinical applications of thyroid echography. N Eng! J Med 287: ll64-1169, 1972 16 Freimanis AK, Asher WM: Echographic study of abdominal lesions. Am J Roentgen 108:747-755, 1970 17 McDonald DC, Leopold GR: Ultrasound B-scanning in the differentiation of Baker's cyst and thrombophlebitis. Br J Radiol45:729-732, 1972 18 Feigenbaum H: Echocardiographic diagnosis of pericardia! effusion. Am J Cardiol26:475-479, 1970 19 Abbasi AS, Flynn JM: The use of modified echocardiographic M-scan technique in the diagnosis of pericardia! effusion. Proceedings of the Scientific Sessions of the American Institute of Ultrasound in Medicine, Philadelphia, October 1972 20 Shah PM, Gramiak R, Kramer DH: Ultrasound localiza·· tion of left ventricular outflow obstruction in hypertrophic obstructive myocardiopathy. Circulation 40:3-11, 1969 21 Abbasi AS, Chahine RA, MacAipin RN, eta!: Ultrasound in the diagnosis of primary congestive cardiomyopathy. Chest 63:937-942, 1973 22 Abbasi AS, MacAlpin RN, Eber LM, eta!: Left ventricular hypertrophy diagnosed by echocardiography. N Eng) J Med 289:118-121, 1973
REFERENCES
1 Schattenberg TT: Echocardiographic diagnosis of left atrial myxoma. Mayo Clin Proc 43:620-627, 1968 2 Wolfe SB, Popp RL, Feigenbaum H: Diagnosis of atrial tumors by ultrasound. Circulation 39:615-622, 1969 3 Popp RL, Harrison DC: Ultrasound for the diagnosis of atrial tumor. Ann Intern Med 71:785-787, 1969 4 Finegan RE, Harrison DC: Diagnosis of left atrial myxoma by echocardiography. N Eng] J Med 282:10221023, 1970 5 Kostis JB, Moghadam AN: Echocardiographic diagnosis of left atrial myxoma. Chest 58:550-552, 1970 6 Allee G, Logue B, Mansour K: Thymic cyst simulating multiple cardiovascular abnormalities and presenting with pericarditis and pericardia! tamponade. Am J Cardiol 31:377-380, 1973 7 Coulshed N, Jones EW, Temple LJ: Cyst of the thymus: report of a case presenting as idiopathic cardiomegaly. Br J Radio! 31:95-99, 1958 8 Podolsky S, Ehrlich EW, Howard JM: Congenital thymic cyst attached to the pericardium. Dis Chest 42:642-644, 1962 9 Schlurger J, Scarpa WJ, Rosenblum DJ, et al: Thymic cyst simulating massive cardiomegaly. Report of a case and review of the literature. Dis Chest 53:365-368, 1968 10 Oldham HN, Sahiston DC: Primary tumors and cysts of the mediastinum presenting as cardiovascular abnormalities. Arch Surg (Chicago) 96:71-75, 1968 11 Shaver VC, Bailey WR, Marrangoni AG: Acquired pulmonic stenosis due to external cardiac compression. Am J Cardiol 16:256-261, 1965 12 Seltzer ItA, Mills DS, Baddocl;: SS. et al: ~fediastinal . thymic cyst. Dis Chest 53:186-196, 1968 .. 13 Abbasi AS, }.lacAipin R};, Eber LM, et al: Echocardiographic diagnosb of idiopathic hypertrophic cardiomyopathy without left ventricular outflow obstruction.
A Simplified Method for Measuring Helium Closing Volume* Kirk McClelland 00 and Charles Mittman, M.D., F.C.C.P.t
A simple method for delivering a constant volume of helium for the measurement of airway closing volume is described. Using a standard fiveway valve and PVC plastic irrigation pipe, a device was constructed which permits the delivery of a uniform volume of helium and avoids the troublesome valve change during inspiration. Results obtained when using this device were comparable to those with the use of a conventional bag to contain the he6um.
T
he measurement of the volume at which small airways in dependent lung zones cease to ventilate (closing volume) has been proposed as a valuable means to detect early disease. Numerous investigators'- 3 use a technique similar to that first reported by Dollfuss and co-workers. • A subject first exhales to residual volume and then inhales slowly to total lung capacity. The initial portion of the inspiration consists of a bolus of some
°From the Respiratory Disease Department, City of Hope Medical Center, Duarte, Ca. ••supervisor, Pulmonary Physiology Laboratory. tJ)ire~r, Department of ltespiratory Piseases . This work was supported' by grants from the National Heart and Lung lnstitute ( l{El2833) and tlte ~ouncil for Tobacco Research. ·· Reprint requests: Mr. McClelland, City of Hope Medical Center, Dtwrte~ California fHOIO ~I:I~ST,
67: 1,
JA~YAij¥,
1975