The pulmonary veins

The Pulmonary By Nancy

E. Budorick,

Virginia

McDonald,

Michael

T

HE PVs have captured relatively little attention in radiology literature. Noninvasive imaging modalities permit a new perspective on the congenital lesions and acquired diseases of these vessels, and renewed interest in them is likely to follow. CT as well as echocardiography and MRI have contributed substantially to the fund of knowledge of the variations and pathology of the PVs. The purpose of this article is to review some of the congenital and acquired diseases of the PVs, with emphasis on their CT appearance.

Veins E. Flisak,

and

Rogelio

M.

Moncada

posterior cardinal veins.‘32 When the embryonic foregut separates into a dorsal alimentary tube and a ventral respiratory tube, the vascular plexus surrounding the foregut also separates, and the resulting two divisions acquire separate communication to the heart.‘,’ The alimentary veins drain through the anterior cardinal system on the right side, namely the SVC and the sinus venosus, which then empty into the right atrium. All the PVs drain through the common PV into the left atrium.“* The common PV divides into left and right branches that then subdivide. The growing left atrium absorbs the common PV as well as the proximal portions of the first branches, resulting in four PVs with separate left atria1 orifices (Fig 1).‘-3

EMBRYOLOGY

By the fourth week of embryogenesis, the primordium of the common PV appears as a solid outgrowth from the sinoatrial region of the heart. This outgrowth projects cranially and eventually joins the foregut vascular plexus caudal to the bifurcation of the lung buds. At this stage, the foregut plexus drains into both anterior and

NORMAL

ANATOMY

Normally there are two superior and two inferior main PVs. The left superior vein drains the left upper lobe, including the lingula. The right superior vein drains the right upper and middle lobes. The inferior veins drain the lower lobes.

ABBREVIATIONS APVD, anomalous pulmonary venous drainage ASD, atrial septal defect AVM, arteriovenous malformation IVC, inferior vena cava MRI, magnetic resonance imaging PA, pulmonary artery PAS, pulmonary arteries PV, pulmonary vein PVs, pulmonary veins WC, superior vena cava

From Medical

the Department of Radiology, Loyola University Center, Maywood, IL. Nancy E. Budorick: Senior Resident; Virginia McDonald: Senior Resident; Michael E. Flisak: Assistant Professor and Vice-Chairman; Rogelio M. Moncada: Professor and Chairman. Address reprint requests to Rogelio M. Moncada, MD. Department of Radiology, Loyola University Medical Center, 2160 S First Ave. Maywood, IL 60153. 0 I989 by W.B. Saunders Company. 0037-I 98X/89/2401-0007%5.00/0

Fig 1. Dorsal view of the normal reabsorption of the common PV and first order branches into the left atrium, that results in four PVs with separate atrial orifices. (A) Embryological appearance. (6) Normal postnatal appearance.

Seminars

in hentgmology,

Vol XXIV,

No 2 (April),

1989:

pp 127-l

40

127

128

The course of the PVs is distinct from that of the bronchoarterial bundles, so that on the frontal radiograph aerated lung separates the PAS from their corresponding veins. In the medial portions of the chest, there is overlap of arteries and veins. In the upper hilar regions on frontal radiographs, it is usually not possible to distinguish the PVs from the PAS. In the lower hilar regions, however, the PVs course more medially and horizontally than the PAS. The right upper PV passes ventral to the right PA, and dorsal to the SVC. As it courses caudally, it passes under the right PA to enter the most superior and lateral aspect of the left atrium. The left upper PV is in close relationship to the left PA. It is located in a ventral position. It also

EUDORICK

ET AL

passes caudally to join the left atrium near the left atria1 appendage. The lower PVs take a more direct and less angled course and enter the most inferior and lateral aspect of the left atrium (Fig 2).4 CONGENITAL

ANOMALIES

Developmental venous anomalies include variations in number, stenosis or dilation, and abnormal pulmonary-systemic connections. A few inconsequential variants of the pulmonary venous drainage occur. A common left or right PV has been reported in approximately 25% of individuals. Most of these are on the left side. Embryologically, there has been incomplete

Fig 2. Normal PVs on CT. The right superior PV courses between the SVC and the right PA to enter the left atrium. The left superior PV courses ventrolaterel to the left PA and enters the left atrium near the left atrial appendage. The inferior PVs are angled posteriorly, end enter the inferoleterel left atrium. LIPV, left inferior pulmonary vein: LSPV, left superior pulmonary vein; RIPV, right inferior pulmonary vein; RSPV, right superior pulmonary vein: SV, superior vena cava, MPA, main pulmonary artery: LPA, left pulmonary artery.

PULMONARY

VEINS

Fig 3. Common left PV (arrowheadsl entering the left atrium (LA). Note drainnge from both lobes of the left lung. There has been incomplete absorption of the primitive common PV.

absorption

of the primitive

common

PV (Fig

3).‘,3

Supernumary PVs may also form, most often a third vein on the right side, that occurs in approximately 1.6% of individuals. Supernumary PVs arise due to excessive resorption of a PV into the atria1 wall beyond its first division (Fig. 4).‘*3 These anomalies are usually without radiographic findings and result in no hemodynamic abnormalities. Pulmonary

Vein Stenosis

Congenital PV stenosis usually involves multiple veins bilaterally, with varying degrees of stenosis.5M8The stenotic regions are located at the junction of the pulmonary veins and the left

Fig 4.

Supranumeraty

PVs.

atrium (Fig S), but may extend peripherally.4 There is fibrous intimal thickening and varying degrees of medial irregularity. It has been suggested that the narrowing of the external caliber of the involved segment is a consequence of the binding character of the intimal disease. The embryologic mechanism leading to PV stenosis is unknown. It is thought that the overgrowth of the intima is primary and the medial abnormality is consequential. There is no inflammatory component.5‘7 On plain radiographs, there is asymmetric vascularity of the two lungs as well as regional variation of vascularity within each lung. There may be a profusion of Kerley lines. Angiographitally, there may be abnormal arterial vascula-

Fig 5. Diagram of PV stenosis. The constrictions most frequently located at the junction of the veins the left atrium.

sre with

BUDORICK

130

ture in addition to asynchronous filling of the constricted PVs.’ The radiographic findings depend on the number of lesions, the degree of stenosis, and the distribution of the PVs involved. The prognosis is poor. There is no medical treatment, and attempts to correct the stenosed veins either by balloon dilation or surgical procedures, such as graft placement or reimplantation of the PVs, have usually resulted in recurrent stenosis and death.6 Cor Triatriatum

In this anomaly the left atrium appears doubled. The accessory “atrium” is actually a dilated common PV that has failed to become absorbed into the left atria1 wall. The dilatation occurs as a result of stenosis of the opening of the common PV into the left atrium (Fig 6).‘992’o Clinical manifestations may occur within the first few days of life or may be delayed until adulthood, depending on the severity of the PV obstruction. The clinical and hemodynamic manifestations may resemble mitral stenosis. Radiographic findings (Fig 6B) vary with the degree of obstruction. The age of the patient may

Fig 6. Cor triatriatum. iA) Diagrammatic representation. that receives the pulmonary veins end is separated from the chest film shows a normal-sized heart with increased pulmonary

ET AL

also be important. In infants the heart is usually not enlarged. There may only be evidence of venous obstruction. In older patients, in addition to longstanding PV obstruction, enlargement of the PAS and right ventricular enlargement may occur. Cardiac catheterization, echo cardiography, CT, or MRI are required to precisely delineate the anatomy and hemodynamics. There are good results with surgical correction.‘-” Anomalous

Pulmonary

Venous

Connections

A number of anomalies of pulmonary venous drainage are known, including partial or total anatomic connection of the PVs to the systemic venous circulation.‘,* The hemodynamic effect of anomalous drainage depends upon how much of the pulmonary bed is emptied into the systemic circulation as well as the presence and nature of associated cardiac anomalies, that occur in 50% of the patients. These include car biloculare, car triloculare biatriatum, dextrocardia, transposition of the great vessels, atrioventricularis communis, truncus arteriosus, coarctation of the aorta, and various types of septal defects.’ APVD may be classified by its embryologic derivation, by anatomy of the venous connection

The common PV remnant left atrium by a membrane venous markings.

forms with

an extracardiac compartment a central perforation. (6) The

PULMONARY

VEINS

131

with persistence of drainage of the pulmonary bed into the right cardinal system.‘-3 (b) Into derivatives of the left cardinal system, such as a persistent left SVC, a vertical vein, or the left brachiocephalic vein (Fig 8). These are thought to arise from persistent drainage of the common PV into the left horn of the sinus venosus. If the left sinus horn atrophies proximal to the common pulmonary vein, a vertical vein will form and connect to the left brachiocephalic vein. (2) Cardiac APVD. (a) Into derivatives of the left cardinal system, namely the coronary sinus (Fig 9). If the left sinus horn atrophies distal to the common PV, drainage will occur through the coronary sinus of the right atrium. (b) Into the right atrium. This is thought to arise from a shift of the atria1 septum to the left, resulting in abnormal position of one or more of the pulmonary veins in the right atrium following resorption of the common PV into the atria1 wall. (3) Infracardiac APVD. (a) Into the umbilicovitelline system (the portal vein or ductus venosus) (Fig 10). This anomaly is rare. The common PV never joins the pulmonary venous

Fig 7. Supracardiic APVD into (A) the azygos (6) the SVC, both derivatives of the right cardinal

vein. and system.

to the systemic circulation,‘3 or on clinical groundsI Perhaps the best classification incorporates the embryologic derivation with the anatomy of the anomalous connection, as follows 1,3,12-18 (1) Supracardiac APVD. (a) Into derivatives of the right cardinal system (SVC or azygos vein) (Fig 7). This is believed to arise from failure of the common PV to form or become completely incorporated into the left atria1 wall,

Fig 8. Supracardiac APVD into remnants of the distal portion of the left cardinal system. The wmmon PV enters a vertical vein that empties into the brachiocephalic vein.

132

BUDORICK

Fig 10.

APVD

at the

infracardiac

level

into

ET AL

the

portal

vein. Fig sinus, cardinal

9. APVD at the cardiac level into a derivative of the proximal portion system (left sinus venosus horn).

the of

coronary the left

bed, so that drainage occurs through the primitive connection to the alimentary veins into the portal system or into the ductus venosus. (b) Into the IVC. This is thought to arise from absence of true PVs. Drainage is accomplished by persistent connection of the foregut plexus with the posterior cardinal system, that eventually communicates with the IVC.ls3 (4) Mixed. Anomalous connections at two or more of the above-described levels. Total APVD requires an interatrial communication for survival, since all of the pulmonary venous drainage is into the right atrium or one of the structures draining into it. In most of these cases the anomalous veins usually join before entering the right atrium or systemic vein.i6*” There are several radiographic appearances suggestive of supracardiac total APVD. Drainage into a left vertical vein may produce a snowman configuration’6*20,21 on the frontal chest film. The head is made up of a dilated SVC on the right and the engorged vertical vein on the left. The body is comprised of an enlarged right atrium on the right and a dilated right ventricle displacing the left heart. On the lateral view, a pretracheal density comprised of the SVC and

the left ventrical vein may be evident before the appearance of a snowman configuration on the frontal view.2’ There also may be posterior and leftward displacement of the barium-filled esophagus by the left vertical vein.16 Drainage into the SVC may cause dilatation of this vessel. Likewise, drainage into the azygos vein may produce its dilatation. At the cardiac level, a dilated coronary sinus is characteristic of APVD into this vessel. Drainage into the right atrium, which is relatively common, presents no specific signs on the plain film. Infracardiac total APVD may show partial obstruction, especially when drainage occurs through the esophageal hiatus into the portal vein. Characteristic pulmonary venous engorgement with a normal-sized heart is found on the plain film. Drainage to the IVC produces less pulmonary venous obstruction. Angiography is required to identify the details of the total anomalous drainage variants. Also important to document with this method is the degree of pulmonary venous obstruction, the diameter of the ASD, and the size of the left heart chambers.‘6*‘7*22 More recently, other modalities have become useful in identifying and studying total APVD, in particular MRI,23 echo-

Fig 11. Total APVD in a patient with multiple csrdiovascutar anomsliis and asplenis. (A) Coronsl MRl section shows PVs that empty into s large confluent vein. (6) On parsssgittal view this vein enters a dilsted right bra&ii vein or SVC. (C and D) Axial section shows the inferior pulmonary veins entering the confluent vein. This pstient also hsd MIstereLPA stresia. Pulmonsry srterlsl ffow is supplii by massively dilated bronchial arteries. There is sn endocsrdisl cushion defect with patent strloventriculsr canal and there is right ventricular hypertrophy. Azygous continustion of the IVC is also present. a, sorts; L. azygous vein; pv, pulmonary veins: SVC, superior vens csvs: AA. right atrium: RV, right ventricle: LA, left atrium: LV, left ventricle; C, confluent vein.

Fig 12. Partial APVD SVC. pv, right pulmonary

to the SVC. CT scsns at soft tissue and lung vein: C, superior vsns csvs: A, sortie arch.

settings

show

the right

superior

PV snsstomoslng

to the

BUDORICK

Fig 13. Partial APVD to right atrium. Angiography patient shows insertion of the inferior right PV into the the flap of which can be seen on this scan (arrowhead).

reveals a right PV entering the right atrium. right atrium, an incidental finding. The patient A, aorta: V. right pulmonary vein; RA. right

and radionuclide injection (Fig 1 I).25 Without surgical correction, most die within the first year of life.‘4’15 In patients less than one month of age, mortality after repair is high, approximately 60%. It is advantageous to wait at least until one month of age, if possible, as the mortality from one month to one year is less than lo%.” Partial APVD is more common than the total variety. It may occur in the right or left lung. Anatomically the PV may connect to the SVC, right atrium, vertical vein, IVC, azygos, or pericardial veins. The most frequent, although usually inconsequential, of all these partial venous anomalies is the right upper PV to the SVC. A sinus venosus type of ASD is the usual accompanying feature of this entity (Fig 12). 1,3,16,17 Partial APVD to the right atrium (Fig 13) or IVC (Fig 14) is probably the next most common lesion. An ASD of the ostium secundum type is usually present. The venous anomaly may coexist with a dysplastic right lung, presenting as a volume deficit, lobation or segmentation abnormality, bronchial hypoplasia, bronchiectasis, right PA hypoplasia, systemic blood supply to the cardiography,24

ET AL

(B) CT scan of e different had an aortic dissection, atrium.

affected lung, or pulmonary sequestration. This combination has been termed congenital venolobar syndrome or scimitar syndrome, named for the plain film finding of the scimitar-shaped anomalous right PV extending inferiorly to the IVC.

Fig 14. Partial APVD, infracardiac. CT at level of the diaphragm shows a large anomalous right PV extending inferiorly toward the abdomen. PV, anomalous pulmonary vein; RA, right atrium, LV, left ventricle; L, liver.

PULMONARY

VEINS

In the left lung, one or both PVs may join the vertical vein. This vessel in turn drains the oxygenated blood into the left innominate vein (Figs 15 and 16). The pathophysiology of partial APVD is basically that of a left-to-right shunt, the degree proportional to the number of veins anatomically connected to the right-sided circulation, the size and flow of the corresponding PAS, the pulmo-

Fig 15. (A) Angiogram of partial APVD from the left lung to the left brachiocephalic vein via a vertical vein. APV, vertical vein; LIV, left brachiocephalic vein; PA, pulmonary artery: RV, right ventricle; SVC, superior vena cava. (B) A similar case with a meandering left PV that eventually entered the left brachiocephalic vein. (Courtesy of Benjamin Felson, Cincinnati.)

135

nary vascular resistance, and any coexisting lung anomalies. Symptoms usually do not occur unless 50% or more of the pulmonary flow is shifted from left to right. Radiographically, partial APVD may be recognized on plain films by seeing the shadow of an anomalous PV3.16,” In addition, evidence of increased pulmonary blood flow with right-sided cardiomegaly may suggest the diagnosis. Fluo-

BUDORICK

Fig 16. left superior that courses brachiocephalic braohiocephalic c, left carotid

ET AL

CT scan on a different patient shows a small pulmonary vein entering s left vertical vein upward and connects with a dilated left vein. The SVC is enlarged. a, aorta: b, left vein; v, vertical vein; s, superior vena cava; artery.

roscopy or tomography may reveal the abnormal PV. Angiography may be necessary to demonstrate the abnormal veins, either by injection of the PAS or direct injection of the anomalous veins via the atrium.18 For patients with allergy to contrast media, a selective one-sided radionuelide study will readily differentiate the abnormal drainage patterni The surgical treatment of partial AVPD consists of reconstruction of the atria1 septum with closure of the associated ASD, and diversion of the anomalous PVs into the left atrium.16 The prognosis is usually good. Pulmonary Vat-ix

A varicosity of the PVs may arise as a consequence of chronic pulmonary venous hypertension or may be congenital in origin.2”29 On the plain film, it may appear as a mass, round, oval, or lobulated, but well defined.27 Under fluoroscopy, it may change size with the Valsalva maneuver. On pulmonary angiography, there is late filling (venous phase) and slow drainage of an abnormally tortuous and dilated PV, near its convergence with the left atrium. MRI can be used to establish the nature and connection of this venous structure (Fig 17). There are usually no symptoms associated with the varix. Hemoptysis, atelectasis of adjacent

Fig 17. Pulmonary varix. (A) Retrocardiac density on cheat radiograph (arrowheads) in a patient with massive cardiac and left atrial enlargement from rheumatic heart disease. (B) On MRI it proves to be a varix of the left inferior PV near its entry into the left atrium. RA, right atrium; LA, left atrium; A, aorta: PV, pulmonary varix.

lung, and bronchial obstruction have been individually reported. 27,29 Treatment is usually unnecessary once the vascular nature of the lesion has been established. Arteriovenous

Malformations

AVM results from a congenital defect in the capillary structure that leads to focal areas of vascular dilatation. It may be isolated or associated with hereditary hemorrhagic telangiectasia (Olser-Weber-Rendu syndrome), in which case similar telangiectatic lesions of the skin, mucosa, GI and GU tracts, and brain may be present.30’32 A pulmonary AVM may appear as a mass on the plain chest radiograph. It is usually well circumscribed, noncalcified, and lobulated. A

PULMONARY

VEINS

feeding artery and a draining vein may also be identified on the plain radiographs. Fluoroscopy and tomography may be used to delineate the feeding and draining vessels. Pulmonary AVM may be multiple, particularly in patients with Osler-Weber-Rendu syndrome. CT scan is often needed to confirm the vascular nature of the AVMs and to exclude neoplastic disease. A lung

Fig 18. This pulmonary AVM presented es a nodule on (Al the PA chest rsdiirsph. (B) Angiography demonstrutes the lesion. (C) On CT, the vessels are identified coursing from the lesion.

137

perfusion scan may also suggest the vascular nature of the lesions.30 Pulmonary angiography is necessary prior to surgical resection or balloon occlusion and helps to eliminate or confirm the presence of other AVMs and to demonstrate the feeding artery as pulmonic or systemic (Fig 18).32 Cardiac catheterization is useful for determining shunt size and characteristics.3’

BUDORICK

138

ET AL

small PAS and PVs by fungal hyphae occurred.42 It has been reported in infants, and most cases occur before middle age. Onset is insidious and symptoms consist of dyspnea and exertional fatigue.43 Prognosis is poor, the condition usually leading to death within 2 years of onset. On plain films, there is cardiomegaly with an enlarged right ventricle and enlarged central PAS (Fig 20). There is pulmonary edema of variable sev-

Fig 19. Massive thrombus in the right pulmonary artery causing anterior displacement and compression of the superior right pulmonary vein and superior vena cava. There is dilatation of the main PA segment. A, aorta; MPA. main pulmonary artery: RPA, right pulmonary artery; T, pulmonary artery thrombus; PV, right superior pulmonary vein; SVC, superior vena cava.

COMPRESSION

OF THE PULMONARY

VEINS

Compression of the PAS has been well described, including its CT appearance.33S35 There may be respiratory distress and unilateral absence of lung perfusion on radionuclide scan.36 In some cases PA compression is accompanied by PV compression. The anatomically complex position of the PVs leaves them vulnerable to impingement by neighboring structures. They may be compressed by enlarged dorsal or subcarinal lymph nodes, a mediastinal mass, or a dilated vascular structure (Fig 19). Not uncommonly they are compressed by a pericardial process, such as constrictive pericarditis or neoplasm. Occasionally the heart may be displaced en bloc and the PVs constricted by the thoracic bony structures. VENO-OCCLUSIVE

DISEASE

Pulmonary veno-occlusive disease is an entity in which thrombosis of the PVs occurs in situ.37”8 In addition to thrombosis, there is thickening of the subintimal layer of the small PVs by fibrous tissue.3g The etiology is unknown, but there is some evidence of an immune complex sequela subsequent to viral illness.4°*4’ In a case of diffuse infection with mucormycosis, occlusion of both

Fig 20. Pulmonary veno-occlusive disease. (A) The frontal chest film shows enlargement of the central pulmonary arteries. (B) On CT scan there are large thrombi in the left atrium and right superior pulmonary vein. RPV, right superior pulmonary vein; LA. left atrium.

PULMONARY

VEINS

Fig 21. Two cases of pulmonary veno-occlusive disease, proved at autopsy. Note the striking Kerley A. 8. and C lines. These changes were chronic in nature. (Courtesy of Dr Benjamin F&on, Cincinnati.)

erity,42 especially of the interstitial variety (Kerley lines) (Fig 21). Of note is lack of redistribution of pulmonary blood flow to the upper lobes, of unknown cause.38 On pulmonary angiography, there is a normal arterial phase with delay in appearance of the venous phase.42 The veins usually appear normal on angiographic study. However, in one postmortem specimen occlusion of some major PVs was founde4’ In Fig 2 multiple contrast-enhanced CT images demonstrate large thrombi in the major PVs and left atrium in a patient with pulmonary veno-occlusive disease.

REFERENCES 1. Gray SW, Skandalakis JE: The pulmonary circulation. In: Embryology for surgeons. Philadelphia: Saunders, 1972;323-58 2. Moore KL: The circulatory system. In: The developing human (ed 3). Philadelphia: Saunders, 1982; 298-343 3. Healey JE: Anatomical survey of anomalous pulmonary veins: Their clinical significance. / Thor Surg 1952;23:433-44 4. Fraser RG, Pare JAP, Pare PD, et al: The normal chest. In: Diagnosis of diseases of the chest (ed 3). Philadelphia: Saunders, 1988: 83-95 5. Adey CK, Soto B, Shin MS: Congenital pulmonary vein stenosis: A radiographic study. Radiology 1986;161:113-7

BUDORICK

140

6. Bini RM, Cleveland DC, Caballas R, et al: Congenital pulmonary vein stenosis. Am J Cardiol1984;54:369-75 7. Edwards JE: Congenital stenosis of pulmonary veins: Pathologic and developmental considerations. Lab Invest 1960;9:46-66 8. Lucas R, Anderson R, Amplatz K, et al: Congenital causes of pulmonary venous obstruction. Pediatr Ciin North Am 1963;10:781-836 9. Niwayana C: Cor triatriatum. Am Heart J 1960;59:291-317 10. Gondin C, Leonard AS, Anderson RC, et al: Cor triatriatum: A diagnostic and surgical enigma. J Thoruc Cardiovasc

Surg

1964;48:527-39

11. Victor S, Santosham R, Rajaram S, et al: Surgical correction of a rare variant of cortriatriatum. J Thorac Cardiovasc Surg 1975;70:354-7 12. Neil1 CA: Development of the pulmonary veins with reference to the embryology of anomalies of pulmonary venous return. Pediatrics 1957;18:880-7 13. Darling RC, Rothurney WB, Craig JM: Total pulmonary venous drainage into the right side of the heart: Report of 17 autopsied cases not associated with other major cardiovascular anomalies. Lab Invest 1957;6:44-64 14. Burroughs JT, Edwards JE: Total anomalous pulmonary venous connection. Am Heart J 1960;59:9 13-3 1 15. Reardon MJ, Cooley DA, Kubrusly L, et al: Total anomalous pulmonary venous return: Report of 201 patients treated surgically. Texas Heart Inst J 1985;12:131-41 16. Chen JT: Radiologic demonstration of anomalous pulmonary venous connection and its significance. CRC Crit Rev Diagn Imaging 1979;11:383-422 17. Bruwer A: Roentgenologic findings in anomalous pulmonary venous connection. Mayo Clin Proc 1953;28:480-8 18. Moes CAF, Freedom RM, Burrows PE: Anomalous pulmonary venous connections. Semin Roentgenol 1985;20: 134-50 19. Burroughs JT, Kirklin JW: Complete surgical correction of total anomalous pulmonary venous connection: Report of 3 cases. Mayo Chin Proc 1956;31:182-8 20. Dalith F, Neufeld H: Radiological diagnosis of anomalous pulmonary venous connection: A tomographic study. Radiology 1960;74:1-18 21. Felson B: Chest roentgenology. Philadelphia: Saunders, 1973; 213 22. Nakib A, Moller JH, Kanjuh VI, et al: Anomalies of the pulmonary veins. Am J Curdiol 1967;20:77-90 23. Fisher MR, Hricak H, Higgins CB: Magnetic resonance imaging of developmental venous anomalies. AJR 1985;145:705-9 24. Liao PK, Su WJ, Hung JS: Two-dimensional echocardiographic diagnosis of total APVD below the diaphragm. Am J Cardiol 1985;56:821-2

ET AL

25. Long WA, Lawson EE, Perry JR, et al: Radionuclide diagnosis of infradiaphragmatic total anomalous pulmonary venous drainage. Pediatr Cardiol 1985;6:69-75 26. Felson B: Fundamentals of chest roentgenology. Philadelphia: Saunders, 1960: 159- 160 27. Fraser RG, Part JAP: Diagnosis of diseases of the chest. Philadelphia: Saunders, 1970:576-7 28. Gottesman L, Weinstein A: Varicosities of the pulmonary veins: A case report and summary of the literature. Dis Chest

1959;35:322-4

29. Byrk D, Levin EJ: Pulmonary varicosity. Radiology 1965;85:834-7 30. Moser RJ III, Tenholder MF: Diagnostic imaging of pulmonary arteriovenous malformation: Evaluation with roentgenographics, sonographics and radionuclide imaging. Chest 1986;89:586-9 31. Dines DE, Arms RA, Bernatz PG. et al: Pulmonary arteriovenous fistulas. Mayo Clin Proc 1974;49:460-5 32. Dines DE, Seward JB, Bernatz PE: Pulmonary arteriovenous fistulas. Mayo Clin Proc 1983;58:176-81 33. Varkey B, Tristani FE. Compression of pulmonary thoracic aneurysm: Perfusion and ventilation changes after aneurysmectomy. Am J Curdiol1974;34:610-4 34. Charnsangavej C: Occlusion of the right pulmonary artery by dissecting aortic aneurysm. AJR 1979;132:274-6 35. Cramer M, Foley WD, Palmer TE, et al: Compression of the right pulmonary artery by aortic aneurysm: CT demonstration. J Comput Assist Tomogr 1985;9:310-4 36. White RI Jr, James AE Jr, Wagner HN Jr: The significance of unilateral absence of pulmonary artery perfusion by lung scanning. AJR 1971;111:501-9 37. Andrews EC Jr: Five cases of an undescribed form of pulmonary interstitial fibrosis by obstruction of the pulmonary veins. Bull Hopk Hosp 1957;100:28-42 38. Brown CH, Harrison CV: Pulmonary veno-occlusive disease. Lancet 1966;2:61-5 39. Tinglestad JB, Alterman K, Lambert EC: Pulmonary venous obstruction. Am J Dis Child 1969;117:217-9 40. Corrin B, Spencer H, Turner-Warwick M, et al: Pulmonary veno-occlusion: An immune complex disease. Pathol Anat Histopath 1974;364:81-91 41. Liebow AA, McAdams AJ, Carrington CB, et al: Intrapulmonary veno-obstructive disease. Circulation 167:2(suppl): 172 42. Heitzman ER: Pulmonary thromboembolism and infarction and pulmonary arterial hypertension. In: Heitzman ER (ed): The Lung, radiologic-pathologic correlation (ed 2). St. Louis: Mosby, 1984:143-8 43. Schiebel RL, Dedeker KL, Gleason DF, et al: Radiographic and angiographic characteristics of pulmonary venoocclusive disease. Radiology 1972;103:47-51