Comparison of the Ultra-low-dose Veo Algorithm With the Gold Standard Filtered Back Projection for Detecting Pulmonary Asbestos-related Conditions
Condition: Asbestos-exposed Workers
Study type: Interventional
Phase: Phase 4

Summary: 
      Asbestos fibers were intensively used throughout the 20th century and remain prevalent in
      developing countries. However, asbestos exposure induces a variety of benign and malignant
      pleural and lung diseases. The most common asbestos-induced neoplasm is lung cancer.
      Moreover, thin-section computed tomography (CT) is more sensitive than a chest x-ray for
      detecting early asbestos-related conditions. Increased exposure to radiation underpins the
      consequences of cancer induction. However, reducing CT doses increases image noise from the
      filtered back projection (FBP) reconstruction. Strategies to reduce radiation exposure
      include the use of iterative reconstruction algorithms. A new algorithm called VeoTM (General
      Electric Healthcare, Milwaukee, MI, USA) decreases the image noise up to 70% compared with
      the gold standard FBP model. Moreover, Veo improves spatial resolution with excellent
      detection of low and high contrast objects from a CT Dose Index (CTDIvol) equal to 0.3 mGy.

      The objective of the present study is to compare Veo with the gold standard FBP for detecting
      pulmonary asbestos-related conditions among workers previously exposed to asbestos.
      Comparisons included radiation delivered and image quality.
    

Detailed description: 
      Asbestos-exposed workers will be recruited following referral to our radiology department for
      the evaluation of asbestos-related disease. CT examinations will be performed with a 64-slice
      CT system (Discovery CT 750HD; GE Healthcare, Milwaukee, WI) and will consist of two
      successive acquisitions. Each examination, the normal-dose (FBP acquisition) and
      ultra-low-dose (Veo acquisition) spiral CT, will be performed in supine position, on the
      entire thorax, at full inspiration and without contrast agent injection.

      In order to perform the two acquisitions without increasing radiation, standard acquisition
      will be performed with the same kV with mA equal to patient's body weight minus 10. To
      conserve image quality, 60 mA will be the inferior limit. The other CT parameters will be
      rotation time 0.5 s and pitch 1.375. Image data will be reconstructed with FBP algorithm.

      The Veo acquisition will be performed with constant CT parameters including: a tube voltage
      of 100 kV, a tube current of 20 mA, pitch of 0.984 and rotation time 0.4 s. Image data will
      be reconstructed with the Veo algorithm.

      Each CT acquisition will be viewed independently by two experienced radiologists (2 to 7
      years of experience). The low-dose images with Veo reconstruction will be interpreted before
      the standard CT and on separate weeks to minimize recall bias. Then, the more experienced
      radiologist will evaluate the detection and characterization of pleuroparenchymal
      abnormalities by a second and simultaneous reading of the Veo and FBP acquisitions. Because
      FBP images are benchmark practice, when a lesion will be found only on Veo images, it will be
      regarded as a false positive.

      The following asbestos-related pleural and parenchymal abnormalities will be recorded as
      present or absent. Pleural abnormalities considered will be: pleural plaques, diffuse pleural
      thickening and pleural effusion.

      CT features of asbestosis will include subpleural dots and branching opacities, curvilinear
      subpleural lines, areas of ground glass opacities, septal lines, reticulations and
      honeycombing.

      Presence of nodules will also be recorded. We will note for each abnormality: localization
      (side, table position) and nature (non-solid, part-solid, solid or calcified).
    

Intervention name(s): New algorithm called VeoTM (General Electric Healthcare, Milwaukee, MI, USA)
Intervention type(s): Device
Intervention description(s): The objective of the present study is to compare Veo with the gold standard FBP for detecting pulmonary asbestos-related conditions among workers previously exposed to asbestos. Comparisons included radiation delivered and image quality.
Allocation: Randomized
Intervention model: Single Group Assignment
Masking: Single (Participant)
Primary purpose: Diagnostic
Keywords: computed tomography; radiation; screening; asbestos; workers; cancer