Journ al of the Korean Radiological Society, 1995: 32( 4) : 595 -605

Lobar Atelectasis : Typical and Atypical Radiographic and CT Findings1

Kyung 500 Lee, M.D., Joong Mo Ahn, M.D., Jung-Gi 1m, M.D.2, Nestor L. Müller, M.D., PhD.3

The characteristic radiographic and CT findings of lobar atelectasis are well known. However, lobar atelectasis is a dynamic process, and atypical presen­ tations may occur due to a number of different causes. Familiarity with the vari­ ous typical and atypical radiographic findings of lobaratelectasis is important for correct diagnosis. The aim of this manuscript is toillustrate the spectrum of radiographic findings of lobar atelectasis and to correlate the radiographic findings with the CT findings. The review will illustrate examples of typical and atypicallobar atelectasis, including combined lobar atelectasis, peripherallobar atelectasis, migrating lobar atelectasis, rounded atelectasis involving the entire lobeand lobaratelectasis mimicking paravertebral and mediastinal masses.

Index Words: Lung, collapse Lung, CT Lung , radiography

made based on findings of the chest radiograph. Com­ INTRODUCTION puted tomography (CT) can be helpful in the assess­ ment of patients with lobar atelectasis, partic 비 arly Volume loss leads to anatomic alterations within the when the radiographic findings are atypical (4-7). CT is atelectatic lobe as well as compensatory changes in also often performed in order to determine the underly­ adjacent structures as they attempt to occupy the space ing cause for the atelectasis. left by the atelectatic lobe (1 - 3). Considerable volume The aims of this manuscript are to illustrate the vari­ loss is required in order to increase the opacity of the 。 us forms of typical and atypical lobar atelectasis on lung. More sensitive findings of atelectasis include dis­ chest radiographs and to correlate the radiographic placement of the interlobar fissures, hila, mediastinum findings of lobar atelectasis with those seen on CT. and bronchi. The presence and conspicuity of the vari­ ous findings is influenced by the severity of atelectasis, Right Upper Lobar Atelectasis type of atelectasis, condition of the underlying lung, as Right upper lobe (RUL) atelectasis results in ove­ well as the presence of extrap 비 monary abnormal ities rinflation of the right middle lobe and shift of the minor such as pleural thickening. Awareness of the various fissure superiorly and medially (Table 1). It also results direct and indirect signs of lobar atelectasis and of in compensatory overinflation of the right lower lobe atypical presentations is important in order to make the (RLL) with shift of the major fissure anteriorly, su­ correct diagnosis. periorly and medially (Fig. 1). The Golden ’s S sign The diagnosis of lobar atelectasis can usually be denotes a centrally located mass with associated lobar atelectasis. The mass should be large enough to be 'DeparlmenlofDiagnoslic Imaging , Samsung Medical Cenler (KSL, JMA) borderforming with the adjacent hyperexpanded lung 2DepartmenlolRadiology , CollegeolMedicine, Seoul Nalional Universily (JG I) (Fig. 1). With complete atelectasis, the RUL is either 3Departmenl 01 Radiology , Universily 01 Brilish Col umbia and Vancouver Hospi­ tal and Health Sciences Cenlre (NLM) pancaked medialiy, simulating mediastinal widening Recipient 01 a Certilicate 01 Merit award lor a scientilic exhibitatthe1994 RSNA or a mediastinal mass (Fig. 2) , or superiorly simulating scienlilic assemb ly and Bronse Medal Award lor a Scienlilic Exhibilatthe 1994 an apical pleural cap Korean Radiological Sociely Meeling On the lateral chest radiograph , an ill - defined Received March 5, 1995; Accepted April17 , 1995 Address reprinl requesls 10 :Kyung Soo Lee, M.D., Deparlmenl 01 Diagnoslic opacity anterior to the trachea and obliteration 01 the Imaging , Samsung Medical Cenler , # 50 Irwon-Dong , Kangnam-Ku , Seoul anterior margin olthe ascending aorta may sometimes 135-230, Korea. Tel. 82- 2- 341 0- 2511 ,2516 Fax. 82- 2-3410- 2559 be the only lindings (1 -3) .

595 - Journ al of th e Korean Radiologica l Soc iety. 1995; 32(4) : 595- 605

The minor fissure changes its position more dra­ aight. concave. or convex (4- 7) matically than does the major fissure. With elevation of the minor fissure. the middle lobe shifts up laterally Left Upper Lobar Atelectasis alongside the atelectatic upper lobe. At CT the middle With LUL atelectasis. the direction of movement is and upper lobes can be seen side- by- side anterior to anterosuperior rather than directly superior as in RUL the major fissure with the superior segment of the atelectasis (Table 2). The left p 비 monary artery. which lower lobe posterior to the fissure (Fig. 1). The major courses over the left main bronchus. restrains the fissure maintains its previous contour. whether str- bronchus and limits the superior migration of the

a b Fig. 1. Typical right upper lobar atelectasis a. Chest radiograph shows right upper lung zone opacity marginated laterally by the elevated right minor fissure. b. Conventional (10 mm collimation) CT scan demonstrates atelectatic right upper lobe marginated laterally by right minor fissure (arrowheads) and posteriorly by right m 러。 r fissure (arrow). Due to central mass. the medial major fissure shows convex border (Golden ’ sSsign)

a b Fig . 2. Right upper lobar atelectasis simulating rightsuperior mediastinal mass a. Chest radiograph shows semilunar opacity abutting right superior mediastinum b. Conventional (10 mm collimation) enhanced CT scan at level of distal trachea shows atelectatic right upper lobe with mucoid impac­ tion in dilated bronchi. Atelectatic upper lobe is sharply marginated laterally by the minor fissure

-「 % J Kyun g Soo Lee, et al: Lobar Atelectasis

atelectatic lobe (8). For this reason, the superior seg­ On OT scans, the atelectatic LUL forms a homo­ ment of the LLL expands upward toward the apex of the geneous 이객 city based on the anterior chest wall and left hemithorax. Therefore atelectasis of the left upper the mediastinum. The posterior margin has a V lobe is associated with increased opacity in the shaped contour from the lung apex to the hilum, where suprahilar region on the PA radiograph. As atelectasis the apex of the V merges with the hilar vessels and progresses, it leads to increased opacity with poorly bronchi. It is these hilar structures, which are relatively defined margins in the perihilar region (Fig. 3a) fixed in position , that tether the major fissure into the On the lateral radiograph, the lateral portion of the V - shape (Fig. 3c). The superior segment of the LLL is major fissure is displaced forward and is placed tan­ pulled forward along both the medial and laterallimbs gentially resulting in a sharp interface (Fig. 3b) of the V. The part of the superior segment that follows

Table 1. Ancillary Radiographic Findings of Atelectasis of Right Upper Lobe

Findings Fissural reorientation Elevated right minor fissure on PA radiograph , minor and major fissure marginate the atelectatic lobe on lateral view Hilum Right hilum elevated to or above the left hilum Mediastinum Tracheal deviation to ipsilateral side, mediastinal shift is less prominent than with lower lobe atelectasis Diaphragm Elevated, diaphragmatic tenting Bronchus Lateral position of bronchus intermedius on PA radiograph, larger lumen of RUL bronchus due to horizontal reorientation on lateral view

Table 2. Ancillary Radiographic Findings of Atelectasis of Left Upper Lobe Findings Fissural reorientation Anterior displacement of major fissure on lateral radiograph Hilum Elevation of left hilum both on PA and lateral radiographs Mediastinum Anterior right lung herniation, producing prominent anterior margin of ascending aorta on lateral view Diaphragm Elevation with peak-I ike contour Bronchus Transverse orientation of left main bronchus resulting in enlarged orifice on lateral radiograph in place of smaller lumen of LUL bronchus

1 ’

a b c Fig. 3. Typicalleft upper lobar atelectasis a. Chest radiograph shows ill-defined opacity in left hilar area. The hyperexpanded superior segment ofthe left lower lobe leads to a lu­ cency between the mediastinum and atelectatic left upper lobe, the so-called Luftsichel (air-crescent) (arrows) b. Lateral radiograph shows anterior displacement of left major fissure. Anterior border of ascending aorta (arrows) is well visualized. c. Conventional (10 mm collimation) CT scan at level of aortic arch shows V-shaped posterior margin of atelectatic left upper lobe. Su­ perior segment of left lower lobe is p 비 led forward along both medial and laterallimbs of V.

- 597 - Journal of the Korean Radiological Society, 1995 : 32 (4) : 595 - 605 the medial limb forms a tongue of lung between the Occasionally the atelectatic lobe may have sharp mediastinum and the atelectatic LUl. This tongue is margins on the PA radiograph simulating a hilar mass visible on PA radiographs and has been called the (Fig. 4 , 5). With marked LUL atelectasis, the contour of Luftsichel (air- crescent) or periaortic lucency (7) (Fig. the major fissure interface may appear continuous with 3c). Less commonly, the major fissure may have a that of the normal epipericardial fat on the lateral straight border rather than a V - shaped contour (Fig. 4) radiograph (Fig. 5).

Fig. 4. Complete atelectasis 01 left upper lobe. a. Chest radiograph shows mass-like lesion in left hilar area. b. Thin-section (1.5collimation) CT scan 。 btained at level 01 carina shows atelectatic left upper lobe. Left upper lobe, being re­ placed only by dilated bronchi, is margi­ nated posteriorly by maj or lissure

a b

Fig. 5. Complete atelectasis 01 left upper lobe simulating left hilar mass a. Chest radiograph shows mass-like lesion in left hilar area. III-delined opacity is als 。 shown superior to mass-like I esion. b. Lateral radiograph shows anteriorly dis­ placed left major fissure, inlerior aspect 01 which is continuous with normal epicardial lat (arrows)

a

Fig. 6. Typical right middle lobar atelecta- 515 a. Posteroanterior chest radiograph shows triangular shaped opacity in right lower lung zone with obliteration of right lower cardiac border b. Lateral radiograph shows triangular 。 pacity in anterior aspect 01 thorax over­ lapped with cardiac silhouette with its apex toward hilum.

a b

-598 - Kyun g Soo Lee, et al: Lobar Atelectasis

Right Middle Lobar Atelectasis creased opacity which obscures the right heart border As the RML loses volume, the minor and major (Fig. 6). In general , the greater the atelectasis and the fissures move toward each other in an inferomedial greater the reorientation of the RML, the more difficult and superomedial direction, respectively (Table 3) it is to recognize the atelectasis on PA radiograph (Fig. The RML thus assumes an oblique orientation and on 7). On the lateral view, RML atelectasis is seen as a tri­ the PA radiograph results in a poorly defined in- angular opacity marginated superiorly by the minor fis-

Table 3 . Ancillary Radiographic Findings of Atelectasis of Right Middle Lobe

Findings Fissural reorientation Inferomedial and superomedial displacement of minor and major fissures respectively Hilum No change in size and position Mediastinum Lack of major mediastinal shift Diaphragm Elevated anteriorly Bronchus Air bronchogram of RML bronchi on PA and lateral view

Fig. 7. Complete atelectasis of right middle lobe a. Chest radiograph shows focal area of dis­ continuity in right lower cardiac border. b. Thin-section (1 .5 mm collimation) CTscan 。 btained at level of inferior p 비 monary vein shows triangular shaped atelectatic right middle lobe replaced by dilated bronchi , marginated anteriorly by right minor fissure

and laterally by right major fissure‘

a b

a b Fig. 8. Atelectasis of right lower lobe a. Chest radiograph shows atelectatic right lower lobe marginated by right major fissure (arrows). Central mass caused outward bulg­ ing of lateral margin of atelectatic right lower lobe. b. Conventional (10 mm collimation) CT scan obtained at subcarinallevel shows central mass (arrowheads) and atelectatic right lower lobe (arrows), marginated by right major fissure. 599 Journal of the Korean Radiological Society, 1995 : 32( 4) : 595 - 605 sure and inferiorly by the major fissure (Fig. 6b). The lower lobar Atelectasis apex of the triangle is in the hilar area, and the base is As the lower lobes become atelectatic, the lateral located peripherally. portion of the major fissure moves posteriorly toward On CT scans, the RML is triangular or trapezoidal the costophrenic angle and may be well delineated on (Fig. 6, 7). Its posterior border, demarcated by the the lateral radiograph (Table 4). The medial portion of major fissure, is usually well defined because the the major fissure relates to the mediastinal wedge of major fissure crosses the scan plane almost pulmonary attachment. The wedge is frequently diffi­ perpendicularly. On the other hand, the interface be­ cult to detect on the lateral radiograph except for a tween RML and RUL is often less distinct because of slight area of increased opacity extending from the the dome- shaped contour ofthe minor fissure. posterior costophrenic angle toward the hilum. On PA

Table 4. Ancillary Radiographic Findings 01 Lower Lobe Atelectasis Findings Fissural reorientation Inleroposterior displacement 01 both major and minor lissures Hilum Downward displacement, small size Mediastinum Obliteration 01 IVC and descending aorta shadow with RLL and LLL atelectasis respectively, contact 01 RUL and LUL with anterior mediastinum with each lobar atelectasis Diaphragm Portions 01 each hemidiaphragm that abuts the atelectatic lower lobe may be obscured 8ronchus Vertical orientation 01 lower lobar bronchus in PA radiograph, posterior and downward displacementol ipsilateral upper lobar bronchus on lateral radiograph

~

1

a Fig. 9. Complete atelectasis 01 ri ght lower lobe a. Chest radiograph shows a line shadow suggesting lateral mar­ gin 01 right major lissure in right retrocardiac area. Note oligemic hilar vessels. b. Thin-section (1.0 mm collimation) CT scan obtained at level 01 distal bronchus intermedius shows posteriorly displaced right minor lissure and atelectatic right lower lobe (arrow) marginated by right major lissure. c. CT scan obtained 10 mm distal to (b) shows a branch (arrow) 01 c right m iddl e I obar bronchus, oriented posteriorly and superiorly.

- 600 Kyung Soo Lee, et al : Lobar Atelectasis

radiographs, the lateral margin of the lobe may be ill through the mediastinum because of its small size (Fig. defined or well defined, depending on whether or not 9). In LLL atelectasis, the involved lobe may appear as the adjacent hyperexpanded lung has placed the a left paraspinal mass instead of the more character­ fissural edge of the lower lobe tangential to the X - ray istic triangular shape with the apex atthe hilum and the beam (Fig. 8) base at the left hemidiaphragm (Fig. 1 이. The appear­ On CT scans, the lower lobes lose volume in a ance of lower lobar atelectasis as a paraspinal mass is posteromedial direction, pulling down the majorfis­ believed to result from incomplete attachment ofthe in­ sure (Fig. 8). The lateral portion of this fissllre ferior p 비 monary ligamentto the hemidiaphragm (9) demonstrates a greater degree of mobility, because the medial portion is fixedto the mediastinum by the Combined Lobar Atelectasis hilar structures and the inferior p 비 monary ligament. Combined lobar atelectasis refers to the condition in If marked atelectasis of the RLL has occurred, the tri­ which the volumes of two lobes of the lung are de­ angular - shaped opacity may be difficult to detect creased simultaneously (1 , 3, 1 이 Because theright

a b Fig. 10. Atypical atelectasis 01 left lower lobe simulating left paraspinal mass a. Chest radiographs shows left hilar prominence and unusual branching pattern 01 hilar vessels. Margin 01 descending aorta is inter­ rupted distally (arrow), suggesting possible left paraspinal mass. Note shilt 01 upper mediastinum to the lelt. b. Conventional (10 mm collimation) CT scan obtained at ventricular level shows atelectatic left lower lobe, posteriorly in paraspinal area

Fig. 11. Combined atelectasis 01 right mi­ ddle and lower lobes due to mucus impac­ tion in bronchus intermedius. a. Chest radiograph shows opacity in right lower lung zone obscuring right atrium and right hemidiaphragm. Inlerior displacement 。 1 major (arrows) and minor (arrowheads) lissures is presen t. Also note inlerior dis­ placement 01 right hilum and hyperexpan- sion 01 ri ght upper lobe b. Lateral radiograph shows opacilication throughout right lower lung zone obscuring right hemidiaphragm. Upper border 01 opacity is bordered anteriorly by minor lis­ sure and posteriorly by major lissure a b

- 601 - Journal of the Korean Radiological Society, 1995; 32(4) : 595-605

a b Fig. 12. Combined atelectasis of right upper and middle lobes due to metastatic endobronchial tumor. a. Chest radiograph shows opacity in right upper and middle lung zones. Cephalad displacement and rotation of hilar vessels are observed. Right hemidiaphragmatic tenting is associated. Also noted are metastatic nodules and mass in left lung. b. Lateral radiograph shows anterior displacement of right major fissure (arrows).

lower lobe atelectasis (1 이 .

Combined Atelectasis of the Right Middle and Lower Lobes Because the bronchus intermedius is the common pathway to the right middle and lower lobes, a single localized lesion involving the bronchus intermedius gives rise to combined atelectasis of these lobes. The bronchial obstruction can be caused by a tumor, a foreign body, a mucous plug, or an inflammatory stric­ ture (10). On the PA radiograph, the atelectatic RLL obscures the right hemidiaphragm, whereas the atelectatic right middle lobe obscures the right cardiac border (Fig. 11) Depression of boththe major and minor fissures is present, the depression being most marked laterally (Fig. 11 a). Other signs of combined atelectasis of the right middle and lower lobes include a small and de­ Fig. 13. Combined atelectasis of right upper and lower lobes due pressed right hilum and decreased vascularity of a to mucus plug. Chest radiograph following general anesthesia hyperexpanded RUL compared with the normal left shows opacities in right upper and lower lung zones , sharply lung. On the lateral view, increased opacity is present marginated by elevated right minor fissure (arrowheads) and de­ throughoutthe lower part ofthe chest. pressed right major fissure (arrows) respectively. Right middle On CT scans, the atelectatic RML and RLL occupy the lobe is overexpanded lower hemithorax and abut the right cardiac border medially and the right hemidiaphragm inferiorly. The right major and minor fissures border the lateral and lung has three lobes, three combinations of combined anteromedial margins ofthe atelectatic lobes, respect­ atelectasis are possible. The most freq i.J ent combi­ ively (Fig. 11). Complete combined RML and RLL atel­ nation is that of middle and lower lobar atelectasis ectasis can be difficult to detect on PA and lateral caused by obstruction of the bronchus intermedius. radiographs. The diagnosis should be suspected in Less commonly seen are combined atelectasis of the patients with a small right hilum and an apparently upper and middle lobes and combined right upper and 이 igemic right lung which represents the hyperex-

- 602 Kyun g Soo Lee, et al : Lobar Atelectasis panded RUL cinoma, the primary tumor can obstruct one bronchus and cause the other bronchus to be obstructed by di­ Combined Atelectasis of the Right Upper and rect extension through the lung parenchyma or peri­ Middle Lobes bronchial sheath or by Iymphadenopathy (1 이 . For combined atelectasis of the RUL and RML to oc­ On the PA radiograph, the atelectatic RUL and RML cur, the bronchi of both lobes must be narrowed or form an opacity that obscures the outline of the medias­ occluded by a single or two separate lesions while the tinum and fades laterally. Combined atelectasis of the bronchus intermedius remains patent, thus allowing RUL and RML can lead to cephalad and lateral dis­ the RLL to remain expanded. Combined atelectasis of placement and rotation of the hilar vessels. The the RUL and RML can occur with bronchogenic carci­ silhouettes of the ascending aorta and the right atrium noma, metastatic tumor, carcinoid tumor, mucous are usually obscured (Fig. 12). On the lateral view, the plug, and bronchialinflammation. In bronchogenic car- major fissure can be seen to be displaced anteriorly.

a Fig . 14. Peripheral atelectasis of combined right upper and middle lobe caused by bronchogenic carcinoma a. Chest radiograph shows poorly defined opacity in right upper and middle lung zones laterally, suggesting localized pleural effusion This opacity is sharply marginated medially by radiolucent lung (arrows). Also noted are cephalad and lateral displacement and ro­ tation of hilar vessels and shift of mediastinum to the right b. Conventional (10 mm collimation) CT scan shows atelectatic upper lobe (arrows) marginated medially by hyperexpanded superior segment of right lower lobe. Also note small right pleural effusion. (Reprinted, with permission, from reference 10)

Fig . 15. Migrating right upper lobe atel ­ ectasis. a. Anteroposterior radiograph shows opacity in right upper lung zone simulating right superior mediastinal mass or apical pleural cap. Inferomedial portion of opacity shows Gol den ’s S sign (arrows) , suggesting

central mass lesion ‘ b. Posteroanterior radiograph shows mi­ grating nature of atelectatic lobe. Atelec­ tatic right upper lobe migrated to right hilar area (arrows). Lateral displacement of right interlobar p비 monary artery and its bran­ ches and 이 igemic right lung are the only findings that suggest lobar atelectasis a b

• 603 - Jou rn al of the Ko rean Rad iologica l Society, 1995 ; 32( 4) : 595- 605

Fig. 16. Rounded atelectasis involving an entire lobe a. Ch est radiograph shows opacity in right retrocard iac area with downward depre­ ssion of right major fissure (arrows) b. Targeted thin-section (1.5 mm collima­ tion) CT scan shows triangular shaped mass abutting the pleu ra in right lower lobe. Whirling of bronchovascular bundles are associ ated. Right m 혀 or fissure (arrows) is depressed inferiorly and rotated medial ly

a

The relative proximity 01 the major 1issure to the an­ lobe is sharply marginated medially. On CT in this form terior chest wall is dependent on the degree 01 atel­ 01 atelectasis, the RML expands upward in front 01 the ectasis 01 the RUL and RM L. Retrosternal radiolu­ atelectatic RUL with the minor fissure adopting an cency, caused by herniation 01 the left lung into the almost coronal orientation. The superior segment 01 retrosternal space, and the accentuated main pulmon­ the RLL herniates upward posterior and medial to the ary artery segment also can be seen on the lateral view atelectatic RUL with the major fissure being reposi­ (Fig. 12). The radiographic 1indings 01 combined atel­ tioned to a more parasagittal orientation superiorly, ectasis 01 the RUL and RML are similar to those of LUL presenting itsel1 as a radiographic inter1ace on the PA atelectasis (1 0) projection (11 -13). The herniated superior segment 01 On CT scan , the atelectatic RUL and RML cause a RLL forms the so called Luftsichel (air crescent) medial wedge-shaped area of soft-tissue attenuation abutting to the atelectatic lobe. Recently two cases of peripheral the chest wall anteriorly and the ascending aorta and atelectasis 01 left upper lobe, caused by bronchogenic right cardiac border medially. This wedge-shaped carcinoma, have also been reported (13). We have opaci1ication extends inferiorly to the level 01 the right seen a case 01 peripheral atelectasis of the combined atrium. The major 1issure is displaced anteriorly, and RUL and RML in a patientwith bronchogenic carcinoma the hyperexpanded lower lobe 1ills most of the right (Fig. 14) hemithorax. Migrating Lobar Atelectasis Combined Atelectasis of the Right Upper and A very heavy lobe, 1illed with fluid, chronic pneu­ Lower Lobes monia, or a tumor, may migrate in the hemithorax with Combined atelectasis of the RUL and RLL is rare. It change in body position adopting a dependent position. may be due to mucous plugs occurring simultaneously Heavy lobes and pedunculated pleural mesotheliomas in the bronchi of the RUL and RL L. The radiographic are the two likely causes of a large migrating chest 1indings of combined atelectasis of RUL and RLL are density (10 , 14). Migrating atelectasis usually involves similar to those 01 isolated atelectasis 01 either lobe a single lobe (Fig. 15) but it has also been described Upper lobe atelectasis leads to elevation of the minor with combined RUL and RML atelectasis. Migratory 10- 1issure, whereas lower lobe atelectasis leads to down­ bar atelectasis should be distinguished from lung tor­ ward and medial shift of the major fissure (Fig. 13). On sion. Radiographic findings 01 lung torsion include CT scans, the minor fissure if higher than normal be­ atypical orientation of the 1issures as well as abnormal cause 01 the atelectasis 01 the RUL and more posterior position and orientation of the pulmonary vessels than normal because of the atelectasis of the RL L. The within the atelectatic lobe (15). middle lobe is overin1lated. Rounded Atelectasis Peripheral Lobar Atelectasis Rounded atelectasis is a form of peripheral pulmon­ Franken and Klatte (11) descri bed the radiographic ary volume loss. Rounded atelectasis is hypothesized 1indings of what they called “atypical (peripheral) right to be due to contraction of a focus of visceral pleural fi­ upper lobe atelectasis ", mimicking apical pleural e1- brosis that results in buckling of the pleura and atel­ fusion. In this type of atelectasis 01 the RUL , the ectasis of underlying lung parenchyma (16). It usually atelectatic lobe continues to lie adjacent to the lateral results in volume loss of part 01 a lobe unrelated to the chest wal l. The dense lateral portion of the atelectatic segmental anatomy. Rounded atelectasis usually pre-

- 604 - Kyung $00 Lee, et a/: Lobar Atelectasis sents as a mass that may sim 비 ate a p 비 monary neo­ s;st Tomogr 1983 ; 7 : 758-767 plasm on chest radiograph. The CTcriteria for the diag­ 6. Naidich DP , Ettinger N, Leitman BS, McCauley DI. CT 01 lobar col­ nosis of rounded atelectasis include (1) a rounded or lapse‘ Sem;n Roentgeno/1984 ; 19: 222-235 oval mass abutting a pleural surface, (2) vessels and 7. Raasch BN , Heitzman ER , Carsky EW, Lane EJ, Berlow ME, Witwer G. Computed tomographic study 01 bronchopulmonary bronchi curving into the mass, and (3) associated collapse. Rad;oGraphics 1984; 4: 195-232 pleural thickening with or without calcification (17) 8. Khoury MB, Godwin JD, Halvorsen RA , Putman CE. CT 01 lobar Although rounded atelectasis is usually confined to a collapse. Invest Radio/1985 ; 20 : 708-716 small portion of lung, occasionally it may involve the 9. Glay J, Palayew MJ. Unusual pattern 01 left lower lobe atelecta­ entire lobe and simulate a large mass (Fig. 16). sis. Radiology 1981 : 141 : 331-333‘ 10. Lee KS, Logan PM , Primack SL , Muller NL. Combined lobar atel- REFERENCES ectasisofthe rightlung: imaging lindings. AJR 1994; 163 : 43-47 11 . Franken EA, Klatte EC. Atypical (peripheral) upper lobe collapse 1. Proto AV, Tocino 1. Radiographic manilestations 01 lobar col- Ann Radio/1977; 20: 87-93 lapse. SeminRoentgeno/1980 ; 15 : 117-173 12. Adler J, Cameron DC. CTcorrelation in peripheral rightupper 10- 2. Mintzer RA, Sakowicz BA, Blonder JA. Lobar collapse. Usual and bar atelectasis. JComput AssistTomogr 1988 ; 12: 51 0-511 unusual lorms. Chest1988; 94 : 615-620 13. Donc C, Desmarais R. Peripheral upper lobe collapse in adults. 3. Lubert M, Krause GR. Further observations on lobar collapse. Radiology 1989 ; 170 : 657-659 RadiolClinNorthAm1963 ;1 :331-346 14. Heitzman ER. The lung:radiologic-pathologic correlation, 2nd 4. Naidich DP , McCauley DI , Khouri NF , Leitman BS, Hulnick DH , ed. St. Louis: Mosby, 1984 :457-501

Siegelman SS. Computed tomography 01 lobar collapse: 1. 15. Felson B. Lung torsion ‘ radiographic lindings in nine cases endobronchial obstruction. J Comput Assist Tomogr 1983 ; 7: Radiology 1987 : 162 : 631-638 745-757 16. Menzies R, Fraser R. Rounded atelectasis. Pathologic and 5. Naidich DP , McCauley DI , Khouri NF , Leitman BS, Hulnick DH , pathogenetic leatures. Am J Surg Patho/1987 ; 11 : 674-681 Siegelman SS. Computed tomography 01 lobar collapse : 2. col- 17. McHugh K, Blaquiere RM. CT leatures 01 rounded atelectasis lapse in the absence olendobronchial obstruction. JComput As- AJR 1989 ; 153: 257-260

대 한 방 사 선 의 학회 지 1995 ; 32( 4) : 595 - 605

대엽성 무기폐:전형적 및 비전형적 단순흉부촬영 및 전산화단층촬영 소견 I

1 삼성의료원 진단방사선과 2 서울대학교병원 진단방사선과 30epartment of Radiology, University of British Columbia and Vancouver Hospital and Health Science Center

이경수 · 안중모 · 임정기 2 • Nestor l. Müller3

대엽성 무기폐의 단순 흉부촬영 및 전산화단층촬영의 특징적 소견은 잘 알려져 있다. 하지만 무기폐는 역동적 과정이어서 비전형적인 소견이 드물지 않게 나타난다. 다양한 형태의 전형적 또는 비전형적인 무기폐의 방사선학적 소견에 친숙함으로 써 무기폐를 정확히 진단할 수 있다. 이 논문의 목적은 대엽성 무기폐의 다앙한 방사선학적 소견을 기술하고 단순촬영 소견 을 전산화단층촬영 소견과 연관시킨것이다. 즉 전형적인 소견과 연합성 무기폐， 말초형 무기폐， 전이성 무기펴 1 ， 원형 무기페 ， 그리고 척추 큰처나 종격동의 종괴 형태로 나타나는 비전형적인 무기폐를 기술한다.

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다.주 제 :신경방사선과학

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마.일 정:

일 시 연 제 연 사

09: 00-09 : 30 Anatomy of normal brain(MRI) 최우석 (경 희 의 대 )

09: 30-10: 00 Anatomy of normal brain(Vascular & Nerve) 서대철 (울산의 대)

10: 00-10 : 30 Brain development & Congenital malformations 김 인원 (서 울 의 대 )

10: 30-10: 45 휴 식

10: 45-11 : 15 Neurosonography 검문철 (소화 아동)

11 : 15-11 : 45 Supratentorial brain tumors(Intra & Extraxial) 서정호 (아 주 의 대 )

11 : 45 -12 : 15 Infratentorial brain tumors (Intra & Extraxial) 주양구 (계 명 의 대 )

λ1 12 : 15 - 13 : 15 점 n

13 : 15 -13 : 45 MR spectroscopy of brain 장기현 (서 울의 대)

13 : 45 -14 : 15 Stroke & Vascular lesions of brain 서정진 (전남의 대)

14: 15 -14 : 45 Inflammatory diseases of brain 조영 덕 ( 고 신 의 대 )

14: 45 -15: 15 Neurodegenerative and White matter diseases 최규호 (가톨릭의대 )

15 : 15 -15 : 30 휴 식

15 : 30 -16: 00 Sellar and parasellar lesions 박동우(한양의 대)

16: 00-16 : 30 Spine(Intramedullary, & Extramedullary

intradurallesions) 김명순 (원 주의 대)

16 : 30 -17 : 00 Spine( Extradurallesions and disc diseases) 정태섭 (연세 의 대)

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