Duet Study

DUET logo 2

The Diagnostic Ultrasound Enthesitis Tool (DUET) Study: Development of a Sonographic Enthesitis Score for Early Diagnosis of Psoriatic Arthritis

Brief description of the DUET Study:

Psoriatic arthritis (PsA) is a type of joint disease that can lead to severe joint damage and disability within the first few years of the disease. This is why early detection and treatment of the disease is essential to prevent serious joint damage and improve long-term outcomes in these patients. However, there is currently no reliable biomarker for PsA, which makes it difficult to detect PsA early. Enthesitis is an inflammation of the area where muscle tendons and ligaments attach to bones. Enthesitis is a key feature in PsA and can be easily detected using ultrasonography. The aim of this research study is to develop a system to evaluate enthesitis using ultrasonography, which can be used as an effective tool in the early detection of PsA. This will help in providing patients with early treatment to prevent further joint damage.

Study Principal Investigators


Primary Research Coordinator

Fahmeen (1)

Figure 1

Prox Pat Lig B-mode_Image (002)

Figure 2


B-Mode (figure 1) and Power Doppler Scan (figure 2) of the proximal patellar ligament in a subject with psoriatic enthesopathy. Loss of Fibrillar echotexture is seen, which correlates to the maximal area of Doppler signal. Note fluffy bone formation at the bony margin.

Study Population:

A total of 400 participants will be recruited for this study, from the 3 following groups:

  • 22 Physicians
  • Patients with Psoriasis, but no joint complaints, or PsA
  • Patients with non-inflammatory joint conditions, such as non-specific back pain, joint pain & stiffness

Study Procedures

All study participants will complete the following procedures:

  • Patient Questionnaire
  • Physical examination by a Physician
  • Ultrasound scanning of their shoulders, elbows, knees, ankles and heels.

Anticipated study outcome:

The study will provide a reliable and valid instrument for the identification of patients with PsA in rheumatology and dermatology settings. Our newly developed tool is expected to improve early detection of PsA by assisting the clinician to distinguish between PsA and other similar conditions. Early diagnosis should facilitate early interventions which will ultimately result in better control of disease activity and improve long term disease outcomes. Furthermore, we anticipate that the new standardized tool will also pave the way to more robust research in the PsA field, by allowing the conduction of ultrasound-based studies exploring approaches to improve the diagnosis and management of PsA.

Study Sites & Co-Investigators:

The DUET study has 21 research sites worldwide. The primary coordinating center is Women’s College Hospital, in Toronto, Canada.

Marker 1

Women's College Hospital


Dr. Lihi Eder

Marker 2

This is Tootlip

Study Timeline

MARCH 2020

Ethics Approval at Primary Coordinating Center

MARCH 2020

Finalized Study Sites Worldwide


Study Training Workshop


Mutual Non-Disclosure Agreements with all sites


Local Ethics Submission & Approval at all study sites


Execution of Site Research Agreements


Study Recruitment & Data Collection


Analysis & publication of results

Additional Resources

*This study is supported by unrestricted research grants from Novartis, Janssen, Pfizer & Eli Lily