MRI of the Pulmonary Circulation

In general, MRI is only considered as a second-line imaging tool for the evaluation of lung disease. Among the major disadvantages to CT are the inferior spatial resolution and longer imaging times. Recent technical developments, such as high performance gradient systems, optimised pulse sequences, and parallel imaging techniques have substantially improved the potential of MRI for the assessment of lung disease.

The morphology of the pulmonary circulation can be assessed by non-enhanced and contrast-enhanced MR angiography. Contrast-enhanced MR angiography may be performed with high spatial and temporal resolution. The latter can be used for a functional assessment of pulmonary blood flow and parenchymal perfusion. Additional functional studies of the pulmonary circulation include phase-contrast MRI and CINE MRI of the right heart. MRI has the unique advantage to combine the assessment of morphology and function in a comprehensive imaging protocol.

MRI of the pulmonary circulation has been evaluated in a variety of lung diseases. One example is pulmonary embolism. Due to the unspecific clinical presentation a high number of patients with suspected pulmonary embolism is finally diagnosed as having no pulmonary embolism. Depending on the clinical probability MRI may be considered as a radiation-free alternative imaging method to rule out pulmonary embolism in patients with low clinical probability for pulmonary embolism. Another potential indication for MRI in pulmonary embolism may be the follow-up of thrombus resolution during anticoagulative therapy. Other pulmonary vascular diseases in which MRI can be effectively used include pulmonary arterial hypertension, arteriovenous-malformation, and congenital heart disease. Also in airway disease and lung cancer MRI of the pulmonary circulation may contribute additional diagnostic information.

Lernziele:

The learning objectives of this contribution are: 1. To review MR imaging techniques for the diagnostic evaluation of the pulmonary circulation. 2. To illustrate clinical indications for the use of MRI in the assessment of pulmonary vascular disease.

Korrespondierender Autor: Fink C

Klinikum Grosshadern, Institut für klinische Radiologie, Marchioninistr. 15, 81377 München

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