Pulmonary Perfusion by Iodine Subtraction Mapping CT Angiography in Acute Pulmonary Embolism (PASEP)

Pulmonary Perfusion by Iodine Subtraction Mapping CT Angiography in Acute Pulmonary Embolism: a Diagnostic Accuracy Study Versus Pulmonary Perfusion SPECT.

• Pulmonary embolism (PE) is a diagnostic and therapeutic challenge. The risk of death of untreated PE is approximately 25%. On the other hand, anticoagulant treatment is associated with a haemorrhagic risk (2% of major haemorrhagic accidents per year, of which 10% are fatal). A diagnostic accuracy is therefore necessary.

• Two approaches are available to diagnose PE:

  1. A functional approach, represented by pulmonary ventilation / perfusion scintigraphy (V / P), which looks for the functional consequences of PE. The main disadvantage of this approach is that there is a high rate of non-diagnostic examinations. On the other hand, it allows a mapping of pulmonary perfusion at the microcapillary scale, and thus allows the quantification of the vascular obstruction index, which would be an independent risk factor of PE recurrence.
  2. A morphological approach, represented by CT pulmonary angiography (CTPA), which allows the visualisation of the clot itself. This approach is currently the most used but has some limitations, including a risk of over-diagnosis of pulmonary embolism and the inability to reliably quantify the index of vascular obstruction.

Lung subtraction iodine mapping CT is a new technique allowing, during the realization of a CTPA, without additional irradiation, to provide a mapping of the iodine. This mapping of iodine could potentially be used to evaluate pulmonary perfusion.

It would then be possible to obtain, during a single examination, in addition to the anatomical information of the thoracic angioscan, information on the pulmonary perfusion and thus to assess the functional consequences of PE.

No study to date has evaluated the performance of the pulmonary subtraction CT for the evaluation of pulmonary perfusion in the context of acute pulmonary embolism suspicion.

Study Overview

• Status: Completed
• Conditions: Pulmonary Embolism
• Intervention / Treatment: Diagnostic test: Pulmonary tomoscintigraphy

• Study Type: Interventional
• Enrollment (Actual): 30
• Phase: Not Applicable

Contacts and Locations

Study Locations

• France
  • Brest, France, 29200
    • CHRU Brest

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• All patients who have been diagnosed with acute pulmonary embolism on the Aquilion One Genesis scan (Toshiba, Medical System, Tokyo, Japan) at the Brest University Hospital, and who have had a mapping of the iodine derived from the subtraction images.

Exclusion Criteria:

• Tomoscintigraphy not feasible within 24 hours.
• Massive pulmonary embolism or with signs of gravity
• Pregnant or lactating women
• Minor patient
• Protected adults
• Incapacity / refusal to give consent
• Hypersensitivity to pertechnetate (99m Tc)
• Hypersensitivity to human albumin

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Perfusion SPECT; Included patients with a diagnosis of acute PE on CTPA and who had a subtraction iodine mapping CT will undergo a SPECT/CT within 24 hours. Each lung subtraction iodine mapping CT will be interpreted blindly by 3 radiologists. Each of the 20 lung segments will be interpreted as normoperfused or hypoperfused. Each perfusion SPECT will be interpreted blindly by 3 nuclear medicine physicians. Each of the 20 lung segments will be interpreted as normoperfused or hypoperfused.

Diagnostic test: Pulmonary tomoscintigraphy; The included patients will benefit from pulmonary tomoscintigraphy within 24 hours after the diagnosis of pulmonary embolism. Each tomoscintigraphy will be interpreted blindly by 3 nuclear physicians. Each of the 20 lung segments will be interpreted as normoperfused or hypoperfused.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The sensitivity of iodine mapping by subtraction technique.	The sensitivity of iodine mapping by subtraction technique for the detection of perfusion defects in pulmonary embolism is evaluated with using pulmonary perfusion tomoscintigraphy as a reference standard .	24 hours

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The specificity of iodine mapping by subtraction technique	The specificity of iodine mapping by subtraction technique for the detection of perfusional defects in acute pulmonary embolism is determinated with using pulmonary perfusion tomoscintigraphy as reference standard.	24 hours
Pulmonary vascular obstruction index	Thé correlation between the pulmonary vascular obstruction index measured by iodine mapping by subtraction technique and that obtained by perfusion tomoscintigraphy is evaluating	24 hours
Concordance CTPA - iodine substraction	The concordance between the morphological abnormalities visualized at the thoracic angioscanner (visualization of an endoluminal defect within the pulmonary arterial network) is evaluated.	24 hours
Concordance CTPA - SPECT	The concordance between the morphological abnormalities on CTPA (visualization of an endoluminal defect within the pulmonary arterial network) is evaluated.	24 hours
Interobserver reproductibility	The interobserver reproducibility of subtraction technique versus pulmonary tomoscintigraphy in reported as normal or abnormal lung perfusion at a segmental level.	24 hours

Collaborators and Investigators

• Sponsor: University Hospital, Brest

Study record dates

Study Major Dates

• Study Start (Actual): June 25, 2018
• Primary Completion (Actual): April 24, 2019
• Study Completion (Actual): April 25, 2019

Study Registration Dates

• First Submitted: June 11, 2018
• First Submitted That Met QC Criteria: July 5, 2018
• First Posted (Actual): July 9, 2018

Study Record Updates

• Last Update Posted (Actual): April 29, 2019
• Last Update Submitted That Met QC Criteria: April 26, 2019
• Last Verified: April 1, 2019

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Respiratory Tract Diseases; Lung Diseases; Embolism and Thrombosis; Embolism; Pulmonary Embolism
• Other Study ID Numbers: 29BRC18.0083 (PASEP)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No