Comparison of 3 Diagnostic Strategies of PE: Planar V/Q Scan, CTPA, and V/Q SPECT.

Summary

Pulmonary embolism (PE) remains a diagnostic challenge. False negative testing exposes patient to the risk of potentially fatal recurrence. False positive testing exposes patients to potentially fatal unduly side effects of anticoagulants.

Current diagnostic strategies rely on the sequential use of pretest clinical probability, Ddimer test, and chest imaging. Two chest imaging modalities have been validated for PE diagnostic exclusion: Computed Tomography Pulmonary Angiography (CTPA) and planar V/Q scan. Main limitations of planar V/Q are the high proportion of non-conclusive results, therefore requiring additional testing and more complex diagnostic algorithms. Main limitations of CTPA are its higher radiation dose and contraindications (renal failure).

In a randomized trial that compared strategies based on CTPA and on planar V/Q scan, a 30% increase in the rate of PE diagnoses was found in the arm using CTPA, raising the hypothesis of over-diagnosing and over-treating PE when using CTPA.

V/Q Single Photon Emission CT (SPECT) is a new method of scintigraphic acquisition that has been reported to improve the diagnostic performances of the test, which could reduce the number of non-conclusive tests and allow simplified diagnostic algorithms.

The investigators hypothesize that a strategy based on V/Q SPECT could be an alternative to the two usual approaches responding rightly to the two mains issues and combining the advantages of CTPA (simplified diagnostic approach) and planar V/Q (no overdiagnosis, lower radiation exposure, no contraindication).

Although a recent survey showed that up to 70% of nuclear medicine centers perform SPECT rather than planar imaging for diagnosing PE, a diagnostic management outcome study, in which diagnostic decision would be made on the basis of a standardized algorithm based on the V/Q SPECT is lacking. Such a study needs to be conducted to ensure that the safety of diagnostic exclusion using a V/Q SPECT based strategy is non-inferior to that of previously validated strategies, and to verify that the use of V/Q SPECT does not lead to over-diagnosis.

Conditions

• Pulmonary Embolism

Interventions

DEVICE

Planar V/Q-based strategy

Strategy based on planar pulmonary scintigraphy

DEVICE

CTPA-based strategy

Strategy based on pulmonary angiography

DEVICE

V/Q SPECT-based strategy

Strategy based on pulmonary tomoscintigraphy

Sponsors & Collaborators

• University Hospital, Brest

  lead OTHER

Principal Investigators

• Pierre-Yves Salaun · CHRU de Brest

Study Design

Allocation

RANDOMIZED

Purpose

DIAGNOSTIC

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2017-04-10

Primary Completion

2024-12-17

Completion

2024-12-17

Countries

• Canada
• France
• Switzerland

Study Locations