Optimizing the diagnosis and assessment of chronic thromboembolic pulmonary hypertension with advancing imaging modalities

Abstract

Imaging is key to nearly all aspects of chronic thromboembolic pulmonary hypertension (CTEPH) including management for screening, assessing eligibility for pulmonary endarterectomy, and post-operative follow-up. While ventilation/perfusion (V/Q) scintigraphy, the gold standard technique for CTEPH screening, can have excellent sensitivity, it can be confounded by other etiologies of pulmonary malperfusion, and does not provide structural information to guide operability assessment. Conventional computed tomography pulmonary angiography (CTPA) has high specificity, though findings of CTEPH can be visually subtle and unrecognized. In addition, CTPA can provide morphologic information to aid in pre-operative workup and assessment of other structural abnormalities. Advances in computed tomography (CT) imaging techniques, including dual-energy CT (DECT) and spectral-detector CT allow for improved sensitivity and specificity in detecting CTEPH, comparable to that of V/Q scans. Furthermore, these advanced CT techniques, compared with conventional CT, provide additional physiologic data from perfused blood volume maps and improved resolution to better visualize distal CTEPH, an important consideration for balloon pulmonary angioplasty for inoperable patients. Electrocardiogram (ECG)-synchronized techniques in ECG-gated CT can also show further information regarding right ventricular function and structure. While the standard of care in the workup of CTEPH includes a V/Q scan, CTPA, direct catheter angiography, echocardiogram, and coronary angiogram, in the future a ECG-gated DECT angiography scan may enable a “one-stop” imaging study to guide diagnosis, operability assessment, and treatment decisions with less radiation exposure and cost than traditional CTEPH imaging modalities.

Patient selection for balloon pulmonary angioplasty: Six‐year results from a high volume PTE surgical center

“…Imaging modalities play a key role in the patient selection process and as imaging continues to improve, we hope that our accuracy improves in parallel. 22 …”

“…Imaging modalities play a key role in the patient selection process and as imaging continues to improve, we hope that our accuracy improves in parallel. 22 Patients with persistent, symptomatic CTEPH after PTE surgery, not candidates for repeat PTE (21%) represent a growing cohort of patients treated with BPA. This is due in large part to the increased awareness of BPA as a treatment option and a growing number of patients living with residual PH after PTE surgery.…”

“…The majority (59%) of patients who underwent BPA at UCSD were deemed to have surgically inaccessible disease after review by our multidisciplinary team and this is expected to remain the largest factor in patient selection for BPA moving forward. Imaging modalities play a key role in the patient selection process and as imaging continues to improve, we hope that our accuracy improves in parallel 22 …”

Chronic thromboembolic pulmonary hypertension: diagnosis, operability assessment and patient selection for pulmonary endarterectomy

“…(III) The combined advantages and disadvantages of pulmonary angiography and CTPA prevent the use of only one of the two techniques to achieve a reliable diagnosis and assessment of operability. (IV) As such, the cumulative radiation and contrast exposure and costs of a V/Q scan, digital subtraction pulmonary angiography, CTPA, and coronary artery catheterization are high (36). Advances in imaging techniques in the last decade try to address these issues.…”

“…A novel approach whereby one imaging study is performed that can provide qualitative and quantitative assessment of pulmonary perfusion, high spatial resolution assessment of the pulmonary arteries and coronary arteries, and morphologic and quantitative assessment of the heart, all with lower radiation exposure and overall cost, is a great desire of every multidisciplinary CTEPH team. A single ECG-gated dual energy CTPA and coronary CT angiography exam was recently proposed by Kligerman and Hsiao as such a strategy (36). Although this strategy provides a promising single imaging study for screening and operability assessment with lower radiation exposure and costs than current practice, it is not yet researched thoroughly nor validated for this purpose.…”