Clinical Scorecard: High-Resolution Photon-Counting Detector CT Findings of Lung Microvasculopathy in Patients with Chronic Thromboembolic Pulmonary Hypertension: A Study of 29 Cases

At a Glance

Key Highlights

• Small-vessel arteriopathy in CTEPH is inaccessible to surgery/intervention and contributes to residual pulmonary hypertension after pulmonary thromboendarterectomy (PEA).
• Photon-counting detector CT (PCD-CT) enables high-resolution imaging potentially detecting morphological changes in lung microcirculation previously below clinical CT resolution.
• Mosaic perfusion pattern on CT, characterized by areas of ground-glass attenuation with enlarged vessels and low attenuation with smaller vessels, reflects redistribution of blood flow and vascular obstruction in CTEPH.

Guideline-Based Recommendations

Diagnosis

• Confirm pulmonary hypertension by right-heart catheterization.
• Diagnose CTEPH via multidisciplinary assessment including cardiologists, pulmonologists, and radiologists.
• Use chest CT angiography with PCD-CT to identify mosaic perfusion pattern and assess lung microvasculature.

Management

• Target central and peripheral pulmonary artery obstructions with pulmonary thromboendarterectomy (PEA) and/or balloon pulmonary angioplasty (BPA).
• Consider pulmonary arterial hypertension (PAH) medications to treat small-vessel microvascular disease in CTEPH.
• Use imaging findings such as poor subpleural perfusion to predict outcomes and guide treatment planning.

Monitoring & Follow-up

• Monitor hemodynamic severity and perfusion defects via imaging and right-heart catheterization.
• Assess lung perfusion and microvascular changes using advanced imaging techniques including PCD-CT.
• Evaluate pulmonary vascular resistance and diffusing capacity (DLCO) to track disease progression.

Risks

• Residual pulmonary hypertension may persist after PEA due to small-vessel arteriopathy.
• Poor subpleural perfusion is associated with worse outcomes post-PEA and BPA.
• Small-vessel disease is not accessible to surgical or interventional treatment, requiring medical management.

Patient & Prescribing Data

Patients with confirmed CTEPH exhibiting mosaic perfusion pattern and small-vessel arteriopathy.

PAH-targeted medications are supported for treating microvascular disease in CTEPH; surgical and interventional procedures address central and peripheral lesions but not small-vessel pathology.

Clinical Best Practices

• Employ multidisciplinary teams for accurate diagnosis and management of CTEPH.
• Utilize high-resolution PCD-CT imaging to detect subtle lung microvascular changes.
• Interpret mosaic perfusion patterns on CT to differentiate hypo- and hyperperfused lung areas.
• Integrate hemodynamic data with imaging findings to guide individualized treatment strategies.
• Recognize limitations of surgical/interventional approaches for small-vessel arteriopathy and incorporate medical therapies accordingly.

References

• Small-vessel arteriopathy role in residual PH after PEA
• Use of PAH medications for CTEPH microvascular disease
• Mosaic perfusion pattern and lung microvascular imaging
• Photon-counting detector CT technology and applications