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Diagnostic Value of Photon-Counting CT in Subsegmental Pulmonary Embolism

2026年5月4日更新者：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.

調査の概要

状態

募集

条件

詳細な説明

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.

研究の種類

観察的

入学 (推定)

696

連絡先と場所

このセクションには、調査を実施する担当者の連絡先の詳細と、この調査が実施されている場所に関する情報が記載されています。

研究場所

中国
- Zhejiang
  - Hangzhou、Zhejiang、中国、310009
    - 募集
    - The Second Affiliated Hospital of Zhejiang University School of Medicine
    - コンタクト：
      
      min Yan, doctor
      
      電話番号：+86 13757118632
      
      メール：zryanmin@zju.edu.cn

参加基準

研究者は、適格基準と呼ばれる特定の説明に適合する人を探します。これらの基準のいくつかの例は、人の一般的な健康状態または以前の治療です。

適格基準

就学可能な年齢

大人
高齢者

健康ボランティアの受け入れ

いいえ

サンプリング方法

非確率サンプル

調査対象母集団

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.

説明

Inclusion Criteria:

Age ≥ 18 years
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
Revised simplified Geneva score ≥ 3
Written informed consent obtained from the patient or the patient's legally authorized representative

Exclusion Criteria:

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

研究計画

このセクションでは、研究がどのように設計され、研究が何を測定しているかなど、研究計画の詳細を提供します。

研究はどのように設計されていますか？

デザインの詳細

グループ/コホートの数

コホートと介入

グループ/コホート
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.

この研究は何を測定していますか？

主要な結果の測定

結果測定	メジャーの説明	時間枠
Detection rate of subsegmental pulmonary embolism (SSPE) using photon-counting CT versus dual-energy CT 時間枠：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

二次結果の測定

結果測定	メジャーの説明	時間枠
Objective image quality scores for SSPE diagnosis 時間枠：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 時間枠：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) 時間枠：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

協力者と研究者

ここでは、この調査に関係する人々や組織を見つけることができます。

スポンサー

Second Affiliated Hospital, School of Medicine, Zhejiang University

研究記録日

これらの日付は、ClinicalTrials.gov への研究記録と要約結果の提出の進捗状況を追跡します。研究記録と報告された結果は、国立医学図書館 (NLM) によって審査され、公開 Web サイトに掲載される前に、特定の品質管理基準を満たしていることが確認されます。

主要日程の研究

研究開始 (実際)

2026年1月1日

一次修了 (推定)

2026年9月1日

研究の完了 (推定)

2027年1月1日

試験登録日

最初に提出

2025年11月17日

QC基準を満たした最初の提出物

2026年5月4日

最初の投稿 (実際)

2026年5月8日

学習記録の更新

投稿された最後の更新 (実際)

2026年5月8日

QC基準を満たした最後の更新が送信されました

2026年5月4日

最終確認日

2025年9月1日

詳しくは

本研究に関する用語

その他の研究ID番号

2025-1248

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