# Magnetic resonance direct thrombus imaging to distinguish acute pulmonary embolism from chronic thromboembolic pulmonary hypertension: a case report

## TL;DR

A case report shows how magnetic resonance imaging can help distinguish between acute and chronic pulmonary thrombotic diseases, guiding treatment decisions.

## Contribution

Demonstrates the potential of magnetic resonance direct thrombus imaging to differentiate acute and chronic pulmonary thrombosis.

## Key findings

- Magnetic resonance imaging showed high-intensity signals in acute thrombi, which disappeared after anticoagulation.
- The patient's condition improved significantly after balloon pulmonary angioplasty for chronic thromboembolic disease.

## Abstract

Acute pulmonary embolism and chronic thromboembolic pulmonary hypertension are both pulmonary thrombotic diseases. However, it is difficult to differentiate between them in some cases, complicating the choice of suitable treatment. Computed tomography pulmonary angiography and D-dimer measurement are helpful for diagnosing these conditions; however, these examinations cannot estimate the efficacy of anticoagulants in the pulmonary artery.

The present case was an 83-year-old woman who had experienced dyspnoea on exertion for 2 months. Computed tomography pulmonary angiography revealed large mural thrombus in the proximal right pulmonary artery, and serum D-dimer concentration was slightly elevated (2.6 µg/mL). Magnetic resonance direct thrombus imaging showed high-intensity signals on T1-weighted images in the area corresponding to the thrombi detected by computed tomography pulmonary angiography. We predicted that the proximal pulmonary artery thrombi were not chronic, and we prescribed an anticoagulant for initial treatment. Seven months later, computed tomography pulmonary angiography showed disappearance of the mural thrombus, and there were no high-intensity signals in the pulmonary artery on magnetic resonance direct thrombus imaging. We diagnosed chronic thromboembolic pulmonary hypertension without proximal lesions after 6 months of anticoagulation therapy according to the elevated mean pulmonary arterial pressure of 32 mmHg. We performed three sessions of balloon pulmonary angioplasty to treat the distal lesions. The patient is well, and her haemodynamics have significantly improved.

Magnetic resonance direct thrombus imaging has the potential to differentiate between acute pulmonary embolism and chronic thromboembolic pulmonary hypertension. Further studies are required because this is only a case report.