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Diagnostic Value of Photon-Counting CT in Subsegmental Pulmonary Embolism

4 mai 2026 mis à jour par: Second Affiliated Hospital, School of Medicine, Zhejiang University

Application of Photon-Counting Computed Tomography in the Diagnosis of Subsegmental Pulmonary Embolism

Pulmonary embolism (PE) is a serious and potentially life-threatening condition caused by blood clots in the lungs. A particular type, subsegmental pulmonary embolism (SSPE), involves very small branches of the pulmonary arteries. Although these clots occur in smaller vessels, their risk of recurrence and complications may be similar to larger clots.

Conventional CT pulmonary angiography (CTPA) is the standard imaging test for suspected PE, but image quality can sometimes be limited by motion artifacts, poor contrast filling, or body habitus, making the detection of SSPE challenging.

Photon-counting computed tomography (PCCT) is a new CT technology that provides higher image resolution, lower radiation dose, and improved visualization of small blood vessels. Early studies suggest PCCT may reduce motion artifacts and increase the accuracy of detecting SSPE compared with conventional CT.

This prospective cohort study will compare PCCT with dual-source CT in patients with suspected acute PE. The study aims to determine whether PCCT improves the detection rate and image quality for SSPE, and whether it can provide more reliable diagnostic information to guide clinical care.

Aperçu de l'étude

Statut

Recrutement

Les conditions

Description détaillée

Pulmonary embolism (PE) is a leading cause of morbidity and mortality worldwide. Subsegmental pulmonary embolism (SSPE), defined as thrombi confined to subsegmental pulmonary arteries, may account for up to 20% of acute PE cases detected by multidetector CT. While distal in location, SSPE carries a risk of recurrent venous thromboembolism and mortality that is comparable to more proximal PE, suggesting that SSPE is not a benign entity. Accurate diagnosis is therefore clinically important, but remains challenging due to motion artifacts, poor contrast opacification, and the large number of small subsegmental vessels that must be evaluated.

Photon-counting computed tomography (PCCT) is a recently developed imaging technology that offers significant improvements over conventional energy-integrating detector CT (EID-CT). PCCT provides higher spatial resolution, direct spectral information, and the ability to generate virtual monoenergetic images and iodine maps in a single acquisition, while reducing radiation dose. Preliminary studies indicate that PCCT can minimize motion artifacts, improve image quality, and enhance visualization of small pulmonary arteries, potentially increasing the detection of SSPE.

This prospective observational cohort study will compare the diagnostic performance of PCCT with dual-source CT in patients with suspected acute PE. The primary outcome is the detection rate of SSPE. Secondary outcomes include image quality scores, radiation dose, and the added diagnostic value of PCCT in patients with negative findings on dual-source CT. By systematically evaluating image quality, detection yield, and radiation exposure, this study seeks to establish the potential role of PCCT as a superior diagnostic tool for SSPE in real-world clinical practice.

Type d'étude

Observationnel

Inscription (Estimé)

696

Contacts et emplacements

Cette section fournit les coordonnées de ceux qui mènent l'étude et des informations sur le lieu où cette étude est menée.

Lieux d'étude

  • Chine
    • Zhejiang
      • Hangzhou, Zhejiang, Chine, 310009
        • Recrutement
        • The Second Affiliated Hospital of Zhejiang University School of Medicine
        • Contact:

Critères de participation

Les chercheurs recherchent des personnes qui correspondent à une certaine description, appelée critères d'éligibilité. Certains exemples de ces critères sont l'état de santé général d'une personne ou des traitements antérieurs.

Critère d'éligibilité

Âges éligibles pour étudier

  • Adulte
  • Adulte plus âgé

Accepte les volontaires sains

Non

Méthode d'échantillonnage

Échantillon non probabiliste

Population étudiée

Adults (≥18 years) presenting with clinical symptoms and signs suggestive of acute pulmonary embolism will be enrolled. Eligible patients are those with a simplified revised Geneva score ≥3 and abnormal findings on electrocardiogram, echocardiography, or pulse oximetry, which support the suspicion of pulmonary embolism. Patients will be prospectively recruited from the emergency department and inpatient wards of the Second Affiliated Hospital, Zhejiang University School of Medicine. The study population is representative of patients with suspected acute pulmonary embolism who require CT pulmonary angiography for diagnostic confirmation.

La description

Inclusion Criteria:

  1. Age ≥ 18 years

  2. Clinical manifestations supporting the diagnosis of acute pulmonary embolism, including:

    Acute onset or progressive dyspnea Unexplained hypoxemia Chest pain Hemoptysis Syncope or presyncope Combined with abnormal findings on electrocardiogram, echocardiography, or pulse oximetry

  3. Revised simplified Geneva score ≥ 3
  4. Written informed consent obtained from the patient or the patient's legally authorized representative

Exclusion Criteria:

  1. Patients requiring prophylactic or therapeutic doses of anticoagulant medication for reasons other than venous thromboembolism (VTE).
  2. Life expectancy less than three months.
  3. Patients unable to undergo CT scanning due to severe condition or hemodynamic instability.
  4. History of allergy to contrast media, renal insufficiency (creatinine clearance < 30 mL/min), or ongoing long-term dialysis.
  5. Pregnancy.
  6. Refusal to provide informed consent or inability to complete follow-up for any reason.

Plan d'étude

Cette section fournit des détails sur le plan d'étude, y compris la façon dont l'étude est conçue et ce que l'étude mesure.

Comment l'étude est-elle conçue ?

Détails de conception

Cohortes et interventions

Groupe / Cohorte
Group 1Title: Conventional CT group
Description: Patients with suspected pulmonary embolism who undergo dual-source or energy-integrating detector CT pulmonary angiography (EID-CTPA).
Group 2 Title: Photon-counting CT group
Description: Patients with suspected pulmonary embolism who undergo photon-counting computed tomography (PCCT) for diagnosis.

Que mesure l'étude ?

Principaux critères de jugement

Mesure des résultats
Description de la mesure
Délai
Detection rate of subsegmental pulmonary embolism (SSPE) using photon-counting CT versus dual-energy CT
Délai: perioperative period
The proportion of patients with suspected acute pulmonary embolism in whom SSPE is detected on photon-counting CT compared with dual-energy CT. All scans will be independently assessed by two blinded radiologists to determine diagnostic yield.
perioperative period

Mesures de résultats secondaires

Mesure des résultats
Description de la mesure
Délai
Objective image quality scores for SSPE diagnosis
Délai: perioperative period
ignal-to-Noise Ratio (SNR) and Contrast-to-Noise Ratio (CNR) will be calculated based on CT attenuation and image noise measured in standardized Regions of Interest (ROIs) within pulmonary vessels, the aorta, and paraspinal muscles. Higher SNR and CNR values indicate better objective image quality.
perioperative period
Subjective image quality scores for SSPE diagnosis
Délai: perioperative period
Radiologists will qualitatively assess image noise and motion artifacts using a 5-point Likert scale (1 = Unacceptable, 5 = Excellent). The average score of the readers will be used, with higher scores indicating better subjective image quality
perioperative period
Incidence of Venous Thromboembolism (VTE)
Délai: 3 months
Occurrence of symptomatic VTE, defined as Deep Vein Thrombosis (DVT) or Pulmonary Embolism (PE), confirmed by objective imaging upon clinical suspicion
3 months

Collaborateurs et enquêteurs

C'est ici que vous trouverez les personnes et les organisations impliquées dans cette étude.

Parrainer

Second Affiliated Hospital, School of Medicine, Zhejiang University

Dates d'enregistrement des études

Ces dates suivent la progression des dossiers d'étude et des soumissions de résultats sommaires à ClinicalTrials.gov. Les dossiers d'étude et les résultats rapportés sont examinés par la Bibliothèque nationale de médecine (NLM) pour s'assurer qu'ils répondent à des normes de contrôle de qualité spécifiques avant d'être publiés sur le site Web public.

Dates principales de l'étude

Début de l'étude (Réel)

1 janvier 2026

Achèvement primaire (Estimé)

1 septembre 2026

Achèvement de l'étude (Estimé)

1 janvier 2027

Dates d'inscription aux études

Première soumission

17 novembre 2025

Première soumission répondant aux critères de contrôle qualité

4 mai 2026

Première publication (Réel)

8 mai 2026

Mises à jour des dossiers d'étude

Dernière mise à jour publiée (Réel)

8 mai 2026

Dernière mise à jour soumise répondant aux critères de contrôle qualité

4 mai 2026

Dernière vérification

1 septembre 2025

Plus d'information

Termes liés à cette étude

Autres numéros d'identification d'étude

  • 2025-1248

Informations sur les médicaments et les dispositifs, documents d'étude

Étudie un produit pharmaceutique réglementé par la FDA américaine

Non

Étudie un produit d'appareil réglementé par la FDA américaine

Non

Ces informations ont été extraites directement du site Web clinicaltrials.gov sans aucune modification. Si vous avez des demandes de modification, de suppression ou de mise à jour des détails de votre étude, veuillez contacter register@clinicaltrials.gov. Dès qu'un changement est mis en œuvre sur clinicaltrials.gov, il sera également mis à jour automatiquement sur notre site Web .

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