Jae Hyung Park, MD #{149} Man Byung Hee Oh, MD #{149} Young

Mitral after

Chung Woo

Stenosis: Percutaneous

To evaluate the pathoanatomic findings of mitral valve stenosis and changes after percutaneous balloon valvuloplasty (PBV), magnetic resonance (MR) imaging was performed in 23 patients. The patients were imaged with a 2.O-T system within 1 week before and 3-10 days after PBV. The angle of the interatrial septum was measured on the transverse image to facilitate a successful transseptal puncture. On MR images, the mean transverse and anteroposterior diameters of the left atrium at the level of the aortic root in the ventricular diastolic phase decreased significantly after PBV. Areas of flow-related intraluminal signal intensity detected in the left atrial cavity of 17 patients (74%) before the procedure disappeared in 15 patients after the procedure. Other MR imaging findings after PBV were the disappearance of intraluminal signal intensity in the pulmonary artery, normal curvature of the interatnal and interventricular septa, and pencardial effusion as a complication. MR imaging was thought to provide useful information before and after PBV in patients with mitral stenosis.

#{149} Jung-Gi

Han, MD Lee, MD

terms:

Heart,

interventional studies, 51.1214

Radiology

anatomy,

procedure,

#{149} Mitral

1990;

#{149} Heart, #{149} Heart, MR

51.92

534.1299

valve,

stenosis,

534.83

177:533-536

MD

Evaluation Balloon

with MR Imaging Valvuloplasty’

M

(MR)

resonance

AGNETIC

imag-

ing has been used to study anatomic details and estimate cardiac function in congenital and acquired heart diseases (1,2). However, only a few reports of the findings of mitral stenosis

at MR

imaging

have

ap-

ous

balloon

been

valvuloplasty

used

without

open

However,

the

heart

such

(5,6).

an invasive

in-

procedure is performed, important to accurately and

objectively evaluate the cardiac omy to prevent complications. MR imaging findings of mitral sis are

has

stenosis

surgery

before

terventional it is very

(PBV)

to relieve

known

to be

related

anatThe steno-

to hemo-

dynamic abnormalities (3,4). Therefore, changes in findings at MR imaging may occur because of hemodynamic

improvement

cessful

PBV

To study of mitral postprocedure

dynamic

after

MR

imaging

and changes

PBV

findings

to evaluate due

improvement,

the findings ing before with mitral

a suc-

procedure.

the stenosis

to hemo-

we analyzed

obtained and after stenosis.

with MR imagPBV in patients

AND

METHODS

performed

in 23 patients (four males, 19 females) with mitral stenosis, from August 1988 to July 1989. The patients ranged in age from 17 to 70 years (mean, 34 years). The diagnosis of mitral was

was made on the basis of clinical and echocardiographic findings. MR imaging was done before cardiac catheterization. Multiple views of the stenosis

coronal, and oblique sagittal planes along the long axis were obtained with an electrocardiographically gated technique on a 2.0-T MR imaging system (Gold Star, Seoul, Korea). Transverse images were obtained at every heartbeat with an echo time (TE) of 30 msec. Transtransverse,

I

From

M.C.H.,

the

Departments

of Radiology

J.G.I.) and Internal

Medicine

Y.W.L.), Seoul National University, dong Chongno-gu, Seoul, 110-744, the 1989 RSNA scientific assembly.

March

22, 1990; revision

vision

received

dress C

reprint

RSNA,

June requests

1990

requested

26; accepted to J.H.P.

(J.H.P.,

(B.H.O., 28 YongonKorea. From Received

May 29; me27. Ad-

June

verse

double-echo

tamed

cry

with

other

rephasing.

TEs

10 mm, with a 2-5-mm gap. The matrix size was 180 X 256. Seven to 10 transverse images were usually obtained sequentially from the level of the aortopulmonary window down to the biventnicular level. The cardiac phase of each image was identified

to compare

constant

peared in the literature (3,4). In mitral valve stenosis, percutane-

MATERIALS Index

Im,

were also oband 60 msec at cv-

the

findings

at a

cardiac

phase. The transverse images at the level of the pulmonary amtery corresponded to the ventricular systolic phase, and the transverse images of the left atrium at the level of the aortic root corresponded to the ventricular diastolic phase. On the basis of the results of

and MR imaging,

echocardiography

the

possibility

of associated left atrial thrombosis was excluded. PBV was performed within 1 week after MR imaging. The indication for PBV was hemodynamically significant mitral stenosis, without other associated valvulam diseases, or mitral regurgitation of

more

than

tions were cent history pulmonary

grade

II-IV.

The contraindica-

left atrial thrombosis or a meof systemic embolism, severe hypertension, acute pulmo-

nary edema, New York Heart Association class IV disease, or combined valvular heart diseases. For PBV, the septal puncture was done initially with a Brockenbrough needle, followed by insertion of an 8-F Mullin transseptal sheath and dilator (USCI Div of C. R. Bard, Billerica, Mass) into the left atrium. A wedge balloon catheter was introduced through the Mullin sheath into the left ventricle across

the

stenotic

mitral

valve,

and

the

balloon catheter was turned at the cardiac apex to pass through the aortic valve. Through this course of the wedge balloon catheter, a 0.035-inch 260-cm-long cxchange guide wire was inserted into the descending thoracic aorta via the mitral

and aortic

valves.

After balloon

dilation

of the septal puncture hole was achieved with an 8-mm balloon catheter, another long exchange guide wire was inserted by means of a double-lumen catheter.

Two balloon ameter

across ually

of

catheters 18-20

mm

the stenotic inflated until

with were

a balloon

di-

introduced

mitral valve the balloon

and manwaist dis-

images of 30

heartbeat to induce even-echo The section thickness was 8-

Abbrevlatloss:

PBV

valvuloplasty,

SD

echo time, TR

-

=

percutaneous

standard deviation, repetition time. -

balloon

TE

533

appeared,

and

rapidly

the

while

tored

(Fig

cessful

balloon

aortic

1). The

in all

23

then

deflated

pressure PBV

was

The

mean

artery mm

(P < .01). ed

pressure ± 24.2

Hg

MR

atnial

after

age)

(the

axis septal

at the

PBV,

an-

to 6.5 mm pulmo-

decreased mm Hg

was the

the

septum

transverse teratnial

also to 28.9

imaging

3-iO days We measured

suc(±

[SD]) pulmonary decreased signifi-

cantly from 24.1 mm Hg ± 0.5 Hg ± 3.8 (P < .01). The systolic nary 53.9

moni-

procedure

patients.

standard deviation tery wedge pressure

was

again

from 13.4

±

conduct-

PBV procedure. angle of the inter-

angle

formed

by

the

of the thorax and the axis on the transverse

level

of the

as a reference

aortic

root

for septal

inim-

Figure

1. (a) Cine radiograph obtained reveals balloon waists caused by mitral the disappearance of the balloon waists

puncture

(Fig 2). We evaluated the size of the left atrium by measuring its transverse and anteropostenior diameters at the level of the aortic root before and after the procedure (Fig 2). The transverse diameter of the

left

atrium

diameter the

was

was

parallel

thorax.

as the transverse

anteropostenior

as the to the evaluation

paired t test. intraluminal in the left the findings firmed by gists.

to the

The

defined

pendicular Statistical

defined

We also flow-related

in

axis

diameter diameter done with

observed

of

nine

during percutaneous valve stenosis. (b) immediately after

(4). a in

atrium after the procedure, and at MR imaging were conthe agreement of two radiolo-

intensities disappeared decreased in six pashowed no change in five

patients,

tients,

and

The pulmonary artery showed high signal intensity during the systolic phase in the second-echo images of six patients before the procedure; this finding disappeared in two patients after the procedure. The curvature of the interatmial septum

RESULTS The range of the angle of the interatmial septum measured before PBV was 8#{176}-54#{176} (mean, 27.3#{176}± 10.5#{176})at the level of the aortic moot. The transverse and anteroposteniom diameters of the left atrium measured at the level of the aortic root in the transverse view are listed in the Table. The mean transverse diameter during the ventricular diastolic phase was 8.5 cm ± 1.2 before PBV. After the procedure, it decreased to 8.2 cm ± i.1 (P < .Oi). The mean anteropostemior diameter at the same level was 4.9 cm ± i.0 before PBV and decreased significantly to 4.3 cm ± 0.9 after the procedure (P < .01) (Fig 3). The decrease of the antemo-

showed

a convexity

the right atrium in 14 patients. The septum deviated by more than 5 mm from the septal axis due to high left atrial pressure before the procedure. The interatrial septum showed a normal flatness in eight patients after the procedure. The curvature of the interventricular septum also showed an abnormal flatness or reversed shape in i2 patients before the pmocedure. After the procedure, the septum

was

normal

in

three

patients

(Fig 5). Penicardial effusion as a complication of the PBV procedure was detected on the MR images of one patient and improved on medical obsemvation. The MR images of one patient showed right pleural effusion-most likely associated with pulmonary infarction before PBV-that improved markedly after the procedure (Fig 5).

with raphy.

demonstrated in the left atrium in of the 17 patients. Areas of flow-related intraluminal signal intensity were revealed in the left atrial appendages of 20 patients (86%). The

teroposteriom diameter, from the postenor wall of the aorta to the posterior wall of the left atrium, is 2.7-4.5 cm, with a mean of 3.5 cm in the parastemnal long-axis view (7,8). Left

#{149} Radiology

15

DISCUSSION Left tial

atrial

nosis. in

enlargement

madiologic Measurement

mitral

is an

finding stenosis

two-dimensional The normal

of of

-

toward

posterior diameter (i7%) was greaten than that of the transverse diameter (4%). Areas of flow-related intraluminal signal intensity were detected in the left atmial cavity of 17 patients (74%) before the PBV procedure (Fig 4). Aften the procedure, the areas of intraluminal signal intensity disappeared, with the usual signal-intensity void

534

double-balloon valvuloplasty Another cine radiograph shows successful dilation.

patients.

per-

changes signal intensity

signal

high

largest

diameter

largest transverse was

b.

a.

before

the

is usually

mitral left

essensteatrium

done

echocardiogrange of the

an-

Figure the

level

2.

Transverse of

the

aortic

MR root

image

obtained

shows

the

of the interatrial septum (a), transverse axis of the thorax, verse (A) and anteroposterior of the left atrium.

at

angle

formed by the and the trans(B) diameters

atnial enlargement is strongly suggested when the anteroposterior diameter is more than 4.5 cm in the pamastemnal long-axis view at two-dimensional echocardiography (7,8). Since every internal structure was well identified with cardiac MR imaging, we attempted to measure the left atrium from a transverse image obtained at the level of the aomtic moot, where the left atrium was located posteriorly between the aomtic root and the descending thomacic aomta. However, volume measurement with MR imaging, rather than a simplc dimensional measurement, is more appropriate for evaluating left atrial size. Because increased left atrial pressure caused an enlargement of the left atrium, the transverse and anteroposterior diameters both decreased significantly after hemodynamic improvement following successful PBV. We found that the anteroposterior diameter was more likely to decrease after successful PBV. The enlarged left atrium caused a displacement and clockwise rota-

November

1990

&

b.

a. Figure

3.

Studies

of a 35-year-old

woman

with

mitral

stenosis.

(a) Transverse

MR image

(TR = 705 msec, TE 30 msec) discloses marked enlargement of the left atrium at the level of the aortic root. The interatrial septum is convex toward the right atrium. Areas of inhomogeneous intraluminal signal intensity are seen in the left atrial cavity. (b) Follow-up MR image obtained 7 days after PBV of the stenotic valve reveals an evident decrease in left atrial size at the same level, along with the disappearance of intraluminal signal intensity and septal

convexity.

Diameter

of Left Atrium

in 23 Patients Transverse

with

Mitral

Stenosis

Diameter

Anteroposterior

Diameter

(cm) Patient Sex/Age

No.1 (y)

Before

After

i/F/28

9.5

8.0

6.0

4.2

2/F/39 3/F/50 4/F/26 5/M/26 6/F/26

7.1 8.8 6.8 9.2 8.4

7.1 8.8 6.8 9.1 8.0

4.0 4.4 4.0 4.4 4.4

4.0 4.4 3.8 4.4 4.0

of

10.3

8.4

6.2

4.0

9.0

8.0

4.0

3.6

9/F/33 iO/F/30 li/M/39 12/F/42

9.3 9.2 11.0 7.6

8.4 9.1 10.5 7.5

4.8 4.8 5.5 5.2

4.4 4.5 4.5 5.5

l3/F/27

6.6

6.3

3.1

2.3

14/F/26

6.3

6.3

3.5

3.1

l5/M/17

8.6

8.4

4.8

3.7

l6/F/30

9.6

9.3

4.4

4.0

l7/F/23

7.1

7.1

4.0

3.8

i8/F/29 i9/F/41

8.0 8.4

8.0 8.4

4.3 5.8

4.0 4.7

20/F/70

8.4

8.4

7.1

6.0

2l/M/3i 22/F/46 23/F/39

10.5 8.0 8.8

10.5 7.6 8.8

6.2 5.6 6.5

6.2 4.9 5.5

the

which

we

verse

MR

ture

should than

such

the

the

177

from

septum, septal

transverse

on

factors

the

In patients the transseptal be directed more usual

with a puncposteni-

#{149} Number

2

of left

of the aortic

root

the

mitral

MR

stenosis,

signal

sluggish

during

imaging of

in

the

an enlarged or without

stenosis

is due flow

in

to the

stagnant left

atrium

an

inadvertent

systemic

Areas of intraluminal signal intensity in the pulmonary artery can appear during the diastolic phase in healthy volunteers and during the systolic phase in patients with pulmonary hypertension (i2,i3). Since pulmonary arterial hypertension is

areas

intensity

obviate

embolism.

pulmonary areas of intmaluminal signal intensity, and doming of the mitral valve have been reported (3,4). Abnormal intraluminal signal intensity in the left atrium in mitral

findings

of

left atrium, artery with di-

posteromedial

level

enlargement,

intraluminal

trans-

the inadvertent cardiac structures,

at the

to

8.2 cm ± 1.1. 4.3 cm ± 0.9.

findings

aorta.

to the

MR images

atnial

angle,

image.

In addition

Volume

a small

to prevent of other as

taken

PBV was 8.5 cm ± 1.2; after, PBV was 4.9 cm ± 1.0; after,

measured

angle,

orly

were

interatnial in

rection, puncture

After

8/F/38

resulting

smaller

Before

7/F/27

Note-Measurements ventricular diastole. * Mean ± SD before t Mean ± SD before

tion

(cm)t

caused by the stenotic mitral valve (3,4,9). In our experience, areas of intraluminal signal intensity were detected in the left atnial appendage more frequently than in the left atnial cavity, most likely because of stagnant blood in the protruded appendage and its small entrance. A high chance of thrombosis in the left atrial appendage could be postulated with these findings. Even after successful PBV, areas of flow-related signal intensity were found in the left atrial appendages in ii patients (48%) during the ventricular diastolic phase. However, the areas of intraluminal signal intensity in the left atrial cavity disappeared in most patients after mitral stenosis was relieved, findings suggestive of hemodynamic impmovement. The differentiation of flow-related intraluminal signal intensity from left atrial thrombosis can be confusing. Areas of flow-related intraluminal signal intensity constantly enhanced homogeneously on the even-echo images (iO,ii). In our experience, the signal intensity of left atrial thrombus on Ti- and T2weighted images varied according to the age and components of the thrombus. However, it was possible to differentiate both conditions with MR imaging by considering the contour and location of the area of abnormally high signal intensity and the degree of enhancement on the even-echo images (iO,li). Thus, we recommended surgery instead of PBV in cases of left atrial thrombosis,

or

secondary to pulmonary venous hypertension in mitral stenosis, the finding is not prevalent on MR images of mitral stenosis. Because the curvatures and shapes of intematrial and interventricular septa also reflect the hemodynamic state induced by the stenotic mitral valve, we could anticipate the depiction of reversible changes on MR images after successful PBV. MR imaging can also reveal pencardial fluid, pleural effusion, and pulmonary infarction, critical findings for clinical management. In addition, MR imaging plays an important mole in precisely depicting anatomy,

atnial

such

as

septum,

the

angle

and

of

the

in helping Radiology

inter-

exclude

#{149} 535

a.

C.

Figure the

4.

Studies

ventricular

of a 37-year-old

diastolic

(b) Second-echo

phase

image

atrium, corresponding phase and at the same decrease in left atrial

woman at the

(TR

1,620

to even-echo level, obtained size.

with

stenosis. (a) Transverse MR image (TR = 800 msec, TE = 30 msec), obtained during aortic root, shows an enlarged left atrium with areas of intraluminal signal intensity. msec, TE = 60 msec) at the same level reveals an area of homogeneously high signal intensity in the left rephasing of the intraluminal flow-related signal intensity. (c) Transverse MR image during the same 5 days after PBV, demonstrates the disappearance of intraluminal flow-related signal intensity and a level

mitral

of the

left atnial thrombus before PBV is performed. In conclusion, MR imaging was thought to provide useful information in patients with mitral stenosis before and after PBV, although the mole of MR imaging in the management of mitral stenosis needs to be investigated further. U References 1.

Didier

D, Higgins

Silverman

2.

heart tients. Higgins

CB,

NH,

Fisher

Cheitlin

MR.

MD.

Osaki

L,

Figure

Congenital

disease: gated MR imaging in 72 Radiology 1986; 158:227-235. CB. MR of the heart: anatomy,

physiology,

and

metabolism.

AJR

pa-

1988;

i 51:239-248. 3.

Hill

JA,

Akins

EW,

Fitzsimmons

CR. Mitral stenosis: magnetic resonance.

JR.

Conti

5.

Studies

of a 32-year-old

woman

with

mitral

stenosis.

(a) Transverse

MR image

(TR = 1,220 msec, TE 30 msec) obtained at the level of both ventricles during systole meveals flatness of the interventricular septum. Segmental pulmonary infarction is demonstrated as a round area of high signal intensity in the right lung and is associated with pleural effusion. (b) Follow-up MR image obtained 10 days after PBV demonstrates restoration of normal septal curvature. Pulmonary infarction and pleural effusion in the right hemithorax

are much

improved.

imaging by nuclear Am J Cardiol 1988;

57:352-354.

4.

5.

Park JH, Han MR evaluation vasc lntervent Lock

JE,

BahI

V, Keane

MC, Oh BH, Im JG, Kim SH. of mitral stenosis. CardioRadiol 1990 (in press).

Khalilullah

commissurotomy nosis. N EngI 6.

Palacios

severe

1987;

75:778-784.

mitral

1985;

313:1515-1518.

PC,

Brandi

S. et al.

valvotomy

mitral

of

. Radiology

two-dimensional

Coil

Cardiol

nance Per10.

echocardiogra-

5:934-938.

thy. Dooms cardiac 1986;

Circulation

1983;

Sechtem

Echocardiography.

heart.

11.

Gomes tra P.

7th

1990; U, Higgins

Lipton

ste-

Schnittinger I, Gordon EP, Fitzgerald PJ, et al. Standardized intracardiac measureJ Am

JM.

McGraw-Hill, 9.

for patients

stenosis.

Felner

JW, ed. The

S. catheter

J Med

balloon

with

ments phy.

536

Percutaneous in rheumatic

I, Block

cutaneous

7.

M, Shrivastava JF.

8.

MJ,

Huyckle

In:

ed. New

Hurst

12.

York:

Sommerhoff

EC.

Magnetic

BA, reso-

imaging of restrictive cardiomyopaAm J Cardiol 1987; 59:480-483. GC,

Higgins

thrombi. 10:415-420.

CB.

J Comput

MR

imaging

Assist

with

of

132. Bouchard

GK,

Fisher

M,

CB. Gated MR intracardiac signals subjects. Radiology A, Higgins

Crooks

LE,

imaging of the in patients and 1985; 156:125-

CB,

Byrd

BF,

Am-

paro EG, Osaki L, Axelrod R. Magnetic resonance imaging in pulmonary arterial hypertension. Am J Cardiol 1985; 56:938942.

AS, Lois JF, Child JS, Brown Cardiac tumors and thrombus:

evaluation 149:895-899.

13.

Tomogr

Schulthess

Higgins heart: healthy

1991-2035. CB,

von

MR

imaging.

AJR

K, Ba1987;

November

1990