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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.

研究概览

地位

招聘中

条件

详细说明

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.

研究类型

观察性的

注册 (估计的)

696

联系人和位置

本节提供了进行研究的人员的详细联系信息，以及有关进行该研究的地点的信息。

学习地点

  • 中国
    • Zhejiang
      • Hangzhou、Zhejiang、中国、310009
        • 招聘中
        • The Second Affiliated Hospital of Zhejiang University School of Medicine
        • 接触：

参与标准

研究人员寻找符合特定描述的人，称为资格标准。这些标准的一些例子是一个人的一般健康状况或先前的治疗。

资格标准

适合学习的年龄

  • 成人
  • 年长者

接受健康志愿者

不

取样方法

非概率样本

研究人群

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.

描述

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.

学习计划

本节提供研究计划的详细信息，包括研究的设计方式和研究的衡量标准。

研究是如何设计的？

设计细节

队列和干预

团体/队列
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.

研究衡量的是什么？

主要结果指标

结果测量
措施说明
大体时间
Detection rate of subsegmental pulmonary embolism (SSPE) using photon-counting CT versus dual-energy CT
大体时间：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

次要结果测量

结果测量
措施说明
大体时间
Objective image quality scores for SSPE diagnosis
大体时间：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
大体时间：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)
大体时间：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

合作者和调查者

在这里您可以找到参与这项研究的人员和组织。

赞助

Second Affiliated Hospital, School of Medicine, Zhejiang University

研究记录日期

这些日期跟踪向 ClinicalTrials.gov 提交研究记录和摘要结果的进度。研究记录和报告的结果由国家医学图书馆 (NLM) 审查，以确保它们在发布到公共网站之前符合特定的质量控制标准。

研究主要日期

学习开始 (实际的)

2026年1月1日

初级完成 (估计的)

2026年9月1日

研究完成 (估计的)

2027年1月1日

研究注册日期

首次提交

2025年11月17日

首先提交符合 QC 标准的

2026年5月4日

首次发布 (实际的)

2026年5月8日

研究记录更新

最后更新发布 (实际的)

2026年5月8日

上次提交的符合 QC 标准的更新

2026年5月4日

最后验证

2025年9月1日

更多信息

与本研究相关的术语

其他研究编号

  • 2025-1248

药物和器械信息、研究文件

研究美国 FDA 监管的药品

不

研究美国 FDA 监管的设备产品

不

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