대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Localized RUL edema in Mitral Regurgitation

Radiologic Findings

Initial chest radiograph shows diffuse calcified pleural thickening in right hemithorax from previous TB pleurisy, and cardiomegaly.

Follow-up chest radiograph shows consolidation of right lung, predominantly in upper lung zone.
Cardiomegaly is persistently observed and sternotomy is due to previous mitral valve replacement operation.

CT scans show consolidation localized in RUL and RML.
Calcified pleural thickening, cardiomegaly and widely opened artificial mitral valvular annuli are observed as well.

Brief Review

Atypical radiologic presentation of pulmonary edema has been described in the literature in relation to various causes:
(1) gravitational effect (prolonged lateral decubitus);
(2) alterations in lung perfusion (pulmonary thromboembolism, chronic obstructive pulmonary disease, Swyer-James syndrome);
(3) alterations in pulmonary venous drainage (unilateral veno-occlusive disease, atrial myxoma);
(4) alterations in intrapleural pressure (abrupt pneumothorax re-expansion); and
(5) alterations in pulmonary ventilation (bronchial obstruction),etc (1-3).

One of the lesser known atypical forms of radiographic presentation of pulmonary edema is the isolated or predominant affection of the right upper lobe in patients with mitral valve insufficiency.

Schnyder et al (4) found radiographic signs of vascular congestion and edema restricted to or predominantly in the RUL in 12 of 131 patients (9%) with severe mitral regurgitation.

The pathogenic mechanism that has been suggested is a regurgitation jet produced in the left ventricular systole in patients with mitral valve insufficiency, with a retrograde flow toward the left atrium.
This jet is oriented especially toward the orifice of the right upper pulmonary vein.
The blood flow, so directed, will increase the formation of edema by accentuating the Starling forces (4, 5).
Associated affection of the RML with the RUL may occurs since the middle lobar vein frequently empties in the left atrium in a joint venous confluent, together with the right upper lobar vein.

Alarcon et al. (6) suggested that certain signs and symptoms might be help with the differential radiologic diagnosis of this entity with respect to other processes with an identical presentation:
1. Patients usually present with clinical symptoms of left heart failure (dyspnea, cough).
2. In the presence of a personal history of mitral valvulopathy, atypical localized pulmonary edema in the RUL should be considered as the first possibility.
3. If there is no additional infection, fever or other infectious signs are absent.
4. Cardiomegaly is common.
5. It is usually accompanied by additional radiologic findings of postcapillary pulmonary hypertension (inverted blood flow distribution, pulmonary vascular blurring, central peribronchial cuffing, septal lines, pleural effusion, etc.).
6. In some cases, the special distribution of the edema fluid, in a central disposition, unlike that which one would expect to find in an infectious process, may provide additional diagnostic information.

References

1. Fraser RG, Pare JAP, Pare RS, Genereux GP. Pulmonary edema. In: Diagnosis of diseases of the chest (vol. 3). Philadelphia: WB Saunders, 1990;1886-1956
2. Calenoff L, Kruglik GD, Woodruff A. Unilateral pulmonary edema. Radiology 1978; 126:19-24
3. Milne ENC, Pistolesi M, Miniati M, Giuntini C. The radiological distinction of cardiogenic and noncardiogenic edema. AJR 1985; 144:879-94
4.Gurney JW, Goodman LR. Pulmonary edema localized in the right upper lobe accompanying mitral regurgitation. Radiology 1989; 171:397-399
5. Schnyder PA, Abdulhakim MS, Duvoisin BE, Kapenberger L, Landry M J-M. Pulmonary edema associated with mitral regurgitation: prevalence of predominant involvement of the right upper lobe. AJR 1993; 161:33-36
6. Alarcon JJ, Guembe P, de Miguel E, Gordillo I, Abellas A. Localized right upper lobe edema. Chest 1995; 107:274-276

Keywords

Lung, Edema, Hydrostatic edema,