MRI semiotics of valve regurgitation
Magnetic resonance imaging (MRI) is a highly informative method for assessing the state of cardiac structures. In tricuspid (tricuspid valve) and mitral (mitral valve) regurgitation, the imaging findings exhibit several characteristic features.
Key radiological findings:
- Regurgitation jet (regurgitation jet): reverse blood flow into the cavities of both atria during ventricular systole is clearly visualized.
- Chamber dilatation: compensatory and pathological enlargement of all heart chambers occurs due to volume overload.
- Effusion: fluid accumulation is frequently detected — pericardial and pleural effusion (pericardiac and pleural effusion).
- Dilatation of the pulmonary trunk (pulmonary trunk): its diameter exceeds 3 cm (assessed by direct comparison with the aortic diameter).
Computed tomography in CTEPH
For patients with chronic thromboembolic pulmonary hypertension (CTEPH, chronic thromboembolic pulmonary hypertension), computed tomography (CT) is the imaging method of choice.
The CT picture in this disease is quite specific:
- The main pulmonary artery (main pulmonary artery) is significantly dilated compared to the ascending aorta (ascending aorta).
- Calcified, organized chronic thromboemboli are visualized in the proximal pulmonary arteries.
- Coronal maximum intensity projection (MIP) views may reveal complete unilateral occlusion of the pulmonary artery (e.g., on the right).
- Collateral blood flow develops: the bronchial arteries (bronchial arteries) are enlarged, and the degree of their opacification (opacification) completely matches that of the aortic arch.
Rare forms of pulmonary hypertension: PVOD and PCH
Pulmonary veno-occlusive disease (PVOD, PVOD) and pulmonary capillary hemangiomatosis (PCH, PCH) are classified into a separate subgroup 1' of the clinical classification of pulmonary hypertension. Imaging methods are critically important for the timely suspicion of these diagnoses.
Pathophysiology and risks: Unlike classical pulmonary arterial hypertension (PAH / PAH), where arterioles are affected, in PVOD and PCH the obstruction is located at the capillary or venous level. This is of paramount clinical importance. Prescribing standard vasodilators (used in PAH) to such patients leads to capillary bed overload and causes life-threatening pulmonary oedema (life-threatening oedema).
General radiological signs of PVOD and PCH:
- Lung parenchyma changes are significantly more pronounced than in routine PAH.
- The picture may resemble hypersensitivity pneumonitis or respiratory bronchiolitis (in patients without PAH).
- Pleural effusion and concomitant lymphadenopathy (lymphadenopathy) are frequently detected.
Differential diagnosis of PVOD and PCH
Despite a similar clinical presentation and the general danger of incorrect therapy, these two conditions have distinct parenchymal features on tomograms.
| Sign | Pulmonary capillary hemangiomatosis (PCH) | Pulmonary veno-occlusive disease (PVOD) |
|---|---|---|
| Main patterns | Diffuse centrilobular nodular opacities (diffuse centrilobular nodular opacities). | Pronounced interlobular septal thickening (interlobular septal thickening). |
| Additional | The nodules are denser, combined with patchy ground-glass opacities and septal thickening. | Smooth septal thickening is a typical sign of interstitial oedema (interstitial oedema). |
Class and exam questions
How to distinguish the pulmonary trunk from the aorta in normal and pathological states?
Normally, the diameter of the pulmonary trunk should not exceed the diameter of the aorta. In valvular regurgitation or pulmonary hypertension, the pulmonary trunk expands by more than 3 cm and visually becomes wider than the aorta on slices.
Why are vasodilators contraindicated in PVOD and PCH?
The drugs dilate arterioles, increasing blood flow. Because the venous and capillary bed is obstructed in these diseases, blood cannot drain, immediately leading to life-threatening pulmonary oedema.
What are the key MRI findings in mitral valve regurgitation?
The main sign is a regurgitation jet into the left atrial cavity. Cardiac chamber dilatation is also observed, and pericardial or pleural effusion may be present.
What else to study on this topic
- Technique of contrast-enhanced cardiac MRI
- Quantitative assessment of regurgitation fraction on MRI
- Classification of pulmonary hypertension (complete breakdown of groups)
- Ground-glass opacity pattern in rare lung diseases
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