Microflow imaging: New Doppler technology to detect low-grade inflammation in patients with arthritis

A K P Lim,D O Cosgrove,K Satchithananda,S Abraham,E A Dick

doi:10.1007/s00330-017-5016-4

Abstract

AimTo assess the efficacy of microvascular imaging in detecting low-grade inflammation in arthritis compared with Power Doppler ultrasound (PDUS).Method and materialsPatients presenting for ultrasound with arthralgia were assessed with grey-scale, PDUS and Superb Microvascular Imaging (SMI). Videoclips were stored for analysis at a later date. Three musculoskeletal radiologists scored grey-scale changes, signal on PDUS and/or SMI within these joints. If a signal was detected on both PDUS and SMI, the readers graded the conspicuity of vascular signal from the two Doppler techniques using a visual analogue scale.ResultsEighty-three patients were recruited with 134 small joints assessed. Eighty-nine of these demonstrated vascular flow with both PD and SMI, whilst in five no flow was detected. In 40 joints, vascularity was detected with SMI but not with PDUS (p = 0.007). Out of the 89 joints with vascularity on both SMI and PDUS, 23 were rated as being equal; while SMI scored moderately or markedly better in 45 cases (p <0.001).ConclusionSMI is a new Doppler technique that increases conspicuity of Doppler vascularity in symptomatic joints when compared to PDUS. This allows detection of low grade inflammation not visualised with Power Doppler in patients with arthritis.Key Points• SMI detects vascularity with improved resolution and sensitivity compared to Power Doppler.• SMI can detect low-grade inflammation not seen with Power Doppler.• Earlier detection of active inflammation could have significant impact on treatment paradigms.

Highlights

Ultrasound is a widely utilised, accessible, crosssectional imaging modality that has the ability to assess the vascularity of lesions by using Doppler technology
It is widely accepted that the capability to detect pathological flow within MSK soft tissues with Doppler ultrasound denotes the presence of local active inflammation [9,10,11,12,13]
Since all non-symptomatic joints in the same patient did NOT exhibit Superb Microvascular Imaging (SMI) Doppler flow, we considered that this represented a true-positive finding rather than a false-positive finding

Summary

Introduction

Ultrasound is a widely utilised, accessible, crosssectional imaging modality that has the ability to assess the vascularity of lesions by using Doppler technology. It has many advantages over other cross-sectional modalities including ease of access, real-time imaging allowing dynamic assessment of the patient, and excellent sub-centimetre spatial resolution [1,2,3,4,5]. The presence of vascularity plays an important role in the assessment of patients with joint or tendon pain, those with an established arthritis as this would denote active disease that may require a modification of treatment or involve a steroid injection. It has been widely accepted that Power Doppler is the standard of care to detect active synovitis in these patients [2,3,4]

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