Journal of the Korean Radiological Society, 1995 : 32(2) : 249- 254

MR Imaging of Primary Cardiac and Pericardiac Tumors1

Myung Kwan Li m , M.D. , Jae Hyung Park, M.D ., Jin Wook Chung, M.D. ,

Ji Hye Kim, M.D. , Yeon Hyun Choe, M.D.2, Man Chung Han , M.D.

Purpose: To evaluate characteristic MR findings of primary cardiac and peri­cardiactumors.

Materials and Methods: There were myxomas (n=기， malignant Iymphoma (n=1 ).Iipoma (n=1). and pericardiac mesotheliomas (n=2) . We analyzed location,

size, shape, signal intensity, contrast enhancement, and associated findings of adjacent structures such as pericardiac and pleural effusion, and mediastinal Iymph node enlargement.

Results: Locations of the myxomas were left atrium in four cases, left ventricle in one, right atrium in one, and right ventricle in one. Mean diameter was 3.5 cm (range, 2-7cm). They were polypoid or lobulated in shape, and attached to interatrial or interventricular septum in all cases except in right atrial myxoma which was attached to lateral wal l. Their peduncles were demonstrated in three left atrial myxomas. The signal intensities were iso or slightly high on T1-weighted images and high on T2-weighted images. Pleural and pericardial effusions were shown in thethree cases. Malignant Iymphoma was manifested as large mass in right ventricle infiltrating to right atrium, interventricular septum, right paratracheal and retrocardiac area. It had slightly high intensity in both T1-and T2-weighted images with a strong contrast enhancement and associated with both pericardiac and pleural effusion. Lipoma was polypoid in shape and at­tached to lateral wall of left ventricle with bright T1 and high T2 signal intensity. Pericardiac mesothelioma was manifested as a pericardiac and atrial mass with diffuse irregular uneven thickening of pericardium which had iso signal on T1-and high T2-weighted images with moderate contrast enhancement.

Conculsion: MR imaging is a very useful method in demonstration of the 10-cation, extent, tissue characteristics of the mass, and relationship with its adjac­ent structures in evaluation of cardiac and pericardiac tumors.

Index Words : Heart, MR Heart, neoplasms

Primary cardiac tumor of the heart is rare , and one ­third of it is malignant(1 , 2). At present time , echocar­diography is the most important non - invasive techhni ­que for imaging of heart, and generally it is an initial imaging procedure(1 , 3 -6). ECG -gated MR imaging has been known to provide high - quality images of the heart and to be useful in the detection of cardiac

1 Department 01 Radiol ogy, Seoul National University Co lI ege 01 Medicine 20epartment 01 Radiology, SamSung Medical Center Received October 1 0, 1994; Accepted January9, 1995 Surported by a grant No. 02.94-0001 Irom the Seoul National University Hospi tal Research Fund Address repr int requ ests to : Myung Kwan Lim, M.O., Oepartment 01 Radiology, Seoul National University Hospital , 28 Yongon.dong Chongn o.gu , Seoul 100-744, Korea. Te l. 82- 2- 760. 2519 Fax. 82.2.743.6385

tumors , thrombi , and pericardiac masses(7 , 8). This re­port is to describe the characteristic findings of MRI in 11 patients with surgically and pathologically proven primary cal"diac and pericardiac tumors.

MATERIALS and METHODS

MR image of 11 patients with surgically and path­。logically proven primary cardiac and pericardiac tumors were reviewed retrospectively. Six male and 5 female patients , ranging in age from 27 to 64 years were examined. AII studies were done with 0.5T superconductive ECG -gated MR imager (Supertech 5000 , GoldStar , Seoul , Korea).

Imaging was done in the transverse plane in all 11

m x

Journ al of the Korean Radiological Society, 1995 ; 32(2) : 249- 254

patiens, with additional imaging in coronal in 8 patients and sagittal plane in 7 patients. Multisection imaging was performed to have seven or fifteen sections per imaging sequences. The spin-echo technique was used with a repetition time (TR) equal to RR interval of the ECG and echo delay time (TE) of 30 msec. The sec­tion thickness was 6 -1 0 mm and sequential images were contiguous.

We analized the tumors in terms of location of the mass, size or extent, shape , signal intensity with het­erogeneity , and degree of contrast enhancemen t. We also reviewed relationship of the tumor to surrounding structure such as pleural effusion , mediastinal Iymph node enlargement, pericardial effusion. Signal inten­sity was compared with cardiac muscles and shape of the mass was classified as exophytic , infilterative , and polypoid.

RESULTS

There were 11 patients with primary cardiac and pericardiac tumors including 7 myxomas , a malignant

a Fig .1 . Myxoma in left atrium.

b

a. Left ventricle is enlarged and there is a polypoid mass with a heterogeneous iso-sig­nal intensity on T1 -weighted image (T1WIl within left atrium. It is attatched to interatrial septum(arrows). Pericardial effusion is noted (1 ong arrows) b, c. Contrast enhanced axial(b) and sagittal (c) images show little enhancement d. On T2WI , this mass shows heterogeneous high signal intensity e. Gradient echo dynamic image shows this mass as a fillin g defect in left atrium

c

Iymphoma, a lipoma, and two pericardiac mesothelio­mas. AII were operated and pathologically proven.

Myxomas were at left atrium in four (Fig. 1) , and left ventricle , right atrium , and right ventriclein one case , respectively. Mean diameter was 3.5 cm with range of 2 -7 cm. They were p이yp이 d or lobulatedin shape, and attatched to interatrial or interventricular septum in ali cases except in right atrial myxoma which was at­tached to lateral wal l. The peduncle was demonstrated in three left atrial myxomas. The signal intensity was iso or slightly high on T1 - weighted images and high on T2 - weighted images. Pleural effusion was shown in 3 cases and pericardial effusion was in 2 cases. There was no mediastinallymph node enlargement.

Malignant Iymphoma was represented with a large right ventricular mass infilterated to right atrium and interventricular septum , and extended to mediastinum , that is , right paratracheal and retrocardiac area (Fig. 2). Its signal intensity was homogeneous and slightly high on both T1 - and T2 - weighted images with a strong contrast enhancement. There was bilateral pleural effusion and minimal pericardial effusion . No

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Myung Kwan Li m, et al: MR Imaging of Primary Cardiac and Pericardiac Tumors

mediastinallymph node enlargement was shown.

Lipoma was polypoid in shape and attatched to lat­eral wall and apex of left ventricle(Fig. 3) with high sig­nal intensity on T1 - and T2 - weighted image. No con­trast enhancement was done. No reaction with sur­rounding structure was shown

In one pericardiac mesothelioma, it was menifested as a diffuse irregular uneven pericardial thickening and partially infilterated to right ventricle , left atrium and right lung(Fig. 4). It had iso signal intensity on T1 weighted image and high T2 signal intensity with mod­erate contrast enhancement. In another pericardiac mesothelioma, diffuse even pericardial wall thickening

was seen with encasement of the aorta and pulmonary artery. The signal intensity was identical with the other one

DISCUSSION

Primary tumors of heart and pericardium are found in less than 0.1 % of autopsy series and are two to three times more often benign than malignant (3 , 4, 7). Meta­stastic neoplasms involving the heart are 20 -40 times more frequent than primary tumors (9 , 1 이. Left atrial myxoma comprises 50% 01 the benign cardiac tumors in adults , while rhabdomyoma , fibroma, and myxoma

a Fig. 2. Lymphoma

b

a. There is a soft tissue mass in right ventricular free wall with extension into left ventricle (white arrow) and interventricular septum (small white arrows). On T1 WI , it shows high signal intensity. There are pericardial effusion (black arrows) and pleural effusion (arrow heads) b. Contrast enhanced coronal scan shows heterogeneous mild enhancemment of the mass with tumoral infilteration to the diaphrag­matic surface (arrows)

a Fig . 3. Li poma

b

a. There is a well -demarcated polypoid mass in left ventricular apex and lateral wall with very high signal intensity on T1 WI.

b. On T2WI, this mass shows slight high signal intensity

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Journal of the Korean Radiological Society, 1995: 32(2) : 249- 254

a Fig. 4. Pericardiac mesothelioma

b c

a, b. There is diffuse uneven pericardial thickening especially in right pericardium and infilteration into right atrium ,Ieft atrium and right lung. This mass shows iso signal intensity on T1 WI(a) , and high signal intensity on T2WI(b) c. Sagittal T1 WI shows homogeneous pericardial thicken ing.

are mostcommon in infants and children (4 -6). In spite of modern diagnostic methods, cardiac tu­

mors still present a diagnostic challenge. These tumo­rs may remain asymptomatic for periods of time , and present with nonspecific symptoms such as chest pain , unexplained heart fail t:J re , embolization , sign of inflow 。 r outflow obstruction , loss of weight , heart murmurs , nonspecific ECG changes , variation in heart size , and pericardial effusion . If a cardiac tumor is suspected from history and physical examination , the first diag­nostic tool should be echocardiography , which is an ef­ficient and noninvasive method. In cases positive for cardiac tumor the following are of special clinical interest : localization , size , infilteration of cardiac str­uctures, hemodynamic effects , vascularization , con­sistency, and histologic class ification .

If, in spite of negative echocardiographic findings , a cardiac tumor is still suspected clinically , additional di­agnostic work - up is mandatory. The following methods can be used: conventional or ultrafast CT with and without contrast enhancement, MR imag ing with and without paramagnetic agents such as gadolinium diethylenetriamine pentaacetate (Gd -DTPA) , angio­graphy , endomyocardial biopsy , and direct surgical procedures (5 , 11 -14). MR and echocardiography share the advantage of direct imaging of the cardiac masses, whereas angiography relies on indirect evi­dence such as filling defects , focal wall thickening , or distortion. The ability of MR to pertorm sagittal and cor­onal imag ing as well as the expanding capability to ob-

tain images in the plane of the short axis of the heart enables MR to define the anatomic location and extent of mass lesions precisely. Additionally , MR imaging , with its wide field of view, can also define any extra­cardiac portions of the mass. A relative disadvantage of CT compared with MR imaging is that diagnostic yield of the former depends to a large extent on the proper timing of the injection of an adequate amount of ionized contrast meterial with scan aquisition at the various anatomical levels. The relative disadvantages of echocardiography are its 1 imitation in obese patients and those with obstructive lung disease, and a much smaller field of view than MR imaging. However , 2D echocardiography has the advantages of thinner tomo­graphic sections and limitless imaging planes(3 , 15).

MR imaging , which provides two - dimensional cro­ss - sectional images ofthe cardiac chambers , is an ac­curate method for detecting cardiac tumors. Rapidly flowing blood , which emits little or no signal , appears black within the chambers of the heart. This enables the excellent separation of blood - filled chambers from the soft tissue that makes up the wall of the chamber. Intracardiac tumors are identifiable within the cham­bers of the heart without contrast enhancement , as used with CT. MR imaging also allows direct imaging in multiple planes - sagittal , coronal , and transaxial. M비­

tiple plane imaging assists in determining the relation­ship of the tumor to various cardiac structures. The images are also obtained without ionizing radiation.

In ECG - gated MR imag ing, the TR interval cannot be

1

ι

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Myung Kwan Li m, et al : MR Imaging of Primary Cardiac and Pericardiac Tumors

chosen freely but is determined by the RR interval of

the patient ’s ECG. The typical TR and TE values on

spin - echo EEG - gated MR imaging fall into the cate­

gory of partial-saturation spin -echo sequences. Such

sequences tend not to differentiate between various

nonfatty soft tissues. Nevertheless, the combination of

intensity characteristics, morphologic information , and

clinical data allowed a correct diagnosis to be made in

several cases. Qualitative tissue characterization was

possible with fatty lesions and those containing large

vascular structures. Relative tissue - intensity charac­

teristics have been shown to allow a degree of speci­

ficity in the MR diagnosis of some cardiac lesions, such

as lipomatous hypertrophy of the atrial septum , fi­

broma, thrombus , myxoma, and pericardial cyst or fat

pad (1 , 4). In our study, specific diagnosis were poss-

ible in myxoma, lipoma and Iymphoma with tissue - in­

tensity characteristics and in pericardiac mesothe-

liomas with morphologic information. That is , hetero­

geneous intermediate or slightly high signal on T1

weighted image and high signal on T2 - weighted image

is seen in cardiac myxoma(15 - 17) , infilterative high

signal intensity lesions on T1 - and T2 - wighted images

in Iymphoma, very high signal mass on T1 - weighted

image and slight high signal intensity on T2WI in lip­

oma(11 , 18 - 20). Also , irregular diffuse uneven thicken­

ing of pericardium is relatively specific morphological

charateristics in pericardial mesothelioma. But, as

others have noted, the primary contribution of MR

imaging in these cases was not its ability to obtain a tis­

sue diagnosis , but rather its ability to delineate the

anatomic extent and to aid in treatment planning (4 , 21 , 22). In conclusion , MR images are useful method in

demonstration of the location , extent, tissue charac­

teristics , and relationship with its adjacent structures in

evaluation of cardiac and pericardiac tumors.

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sistTomogr1989 ; 13 : 627-632

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4. Lund JT. Ehman RL . Julsrud PR. Sinak LJ . Tajik AJ. Cardiac

masses: assessment by MR imaging. AJR 1989 ‘ 152 : 469-473

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Comput Assist Tomogr 1989 ; 13 : 621-626

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7. Gomes AS . Lois JF. Child JS. Brown K. Batra P. Cardiac tumors and thrombus:evaluation with MR imaging. AJR 1987 ;149

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cardiac and paracardiac lesions. AJR 1989 ; 153 : 47-50 10. Lee R. Fisher MR. MR imaging 01 cardiac metastasis Irom mal i g­

nant librous histiocytoma. J Comput Assist Tomogr 1989 ; 13 126-128

11. Conces DJ . Vix VA. Tarver RD. Diagnosis 01 a myocardiallipoma by using CT. AJR 1989; 153 : 725-726

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malignant thymoma :CT diagnosis. J Comput Assist Tomogr

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15. Conces DJ . Vix VA. Klatte EC. Gated MR imaging 01 left atrial myxomas. Radiology 1985; 156 : 445-447

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inlarction : MR lindings. J Comput Assist Tomogr 1989 ; 13 123-125

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18. Kaplan KR . Rilkin MD. MR diagnosis 01 lipomatous inlilteration 01 the interatrial septum. AJR 1989 ; 153: 495-496

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Journal of the Korean Radiological Society, 1995 : 32(2) : 249-254

대 한 방 사 선 의 학 회 지 1995: 32(2) : 249-254

원발성 심장및 심막종양의 자기공명영상I

I 서울대학교 의과대학 방사선과학교실

2삼성의료원 방사선과

임명관 · 박재형 · 정진욱 · 김지혜 · 최연현2 • 한만청

목 적 :원발성 심장 및 심막 종앙의 특징적인 자기영상소견을 알아 보고자 하였다.

대상 및 방법 :7예의 점액종， 악성 림프종， 지방종 각 1 예， 심막중피종 2예등 총 11예의 종양이 대상이었으며， 자기공명영

상소견에서 종괴의 위치와 크기， 모앙， 신호강도와 초영증강정도를 분석하였고 심막 혹은 늑막삼출이나 종격동 림프질의 비

후등 동반된 소견들을 분석하였다.

결 과:점액종의 위치는 좌심방이 4예로 가장 많았고 그 외 좌심실과 우심방， 우심실이 각각 1예씩이었다. 평균 크기는

3.5cm(2-7 cm 범위)였다. 모앙은 폴립앙이거나 분엽 모앙이었고 외측벽에 붙어 있었던 1예의 우심방의 종괴를 제외하면

모두에서 심방중격 혹은 심실중격에 붙어 있었다. 종괴경 (peduncle)은 3예의 좌심방 점액종에서 보였다. 신호강도는 Tl강조

영상에서는 심장근육에 비해 같거나 약간 높고 T2 강조영상에서는 높은 신호강도를 나타내었다. 심막삼출과 늑막삼출이 각

각 3예에서 보였다. 악성 림프종은 커다란 우심실의 종괴로 나타났으며 우심방과 심실중격， 우측 기관주위와 심장후방공간

을 광범위하게 침범하고 있었다. Tl 및 T2강조영상에서 모두 약간 높은 신호강도를 보였으며 강하게 조영증강이 되었고 심

막 및 는막삼출이 동반되었다. 지방종은 폴립앙으로 좌심실의 외측벽에 붙어 있었다. 특징적으로 Tl강조영상에서 매우 높은

신호강도를 T2강조영상에서도 높은 신호강도를 나타내었다. 심막 중피종은 우측 심막과 앙측 심방의 종괴로 나타났으며 심

막의 전반적인 불규칙적인 비후 소견을 보였다. Tl강조영상에서는 주위 근육과 비슷한 신호강도를 T2강조영상에서는 높은

신호강도를 나타냈으며 중등도로 조영증강 되었다.

결 론:자기공멸영상은 여러 신호강도와 여러 단면영상으로 심장 및 심막 종괴를 평가함에 있어， 그 위치나 크기， 조직학

적 특성 및 주위 조직간의 관계를 보는데 매우 유용할 것으로 생각된다.

않