Ultrasound Definition of Tendon Damage in Patients With RA
Ultrasound Definition of Tendon Damage in Patients With RA
The study was carried out in two steps. The first step consisted of a Delphi exercise, aiming to find agreement on ultrasound definitions of normal tendons, peritendinous structures, tenosynovitis and tendon damage in RA; furthermore, the Delphi exercise was done to reach consensus on the ultrasound grading of tenosynovitis and tendon damage in RA patients. Details on the methodology of the first step have previously been reported by Naredo et al.
The first step of the study was followed by a two-day patient-reliability exercise, which took place in Amsterdam, The Netherlands. Each day was divided in a morning and an afternoon session. The afternoon session was a repetition of the morning session in order to assess the intraobserver reliability.
Patients. Twelve patients with RA according to the American College of Rheumatology 1987 criteria representing all degrees of disease activity (severe, moderate, low and remission as defined by DAS28) were recruited from the outpatient rheumatology clinic (MC Groep hospitals). Demographic and clinical data were recorded for all patients.
The 12 patients were equally divided over 2 days. Both wrists and ankles were studied for the ultrasound investigation. All patients were assessed twice, that is, during the morning and again in the afternoon. The local ethics committee approved the study and all patients gave written consent according to the Declaration of Helsinki.
Ultrasonographers. Twelve rheumatologists with extensive experience in ultrasound, that is, more than 10 years, participated in the present study.
Tendons. At the wrist, the following extensor tendons enclosed in a synovial sheath were selected: the second extensor compartment, that is, the extensor carpi radialis brevis and longus; the third, that is, the extensor pollicis longus (EPL); the fourth, that is, the extensor digitorum communis (EDC); the fifth, that is, the extensor digiti minimi (EDM); and the sixth, the extensor carpi ulnaris (ECU). At the ankle, the tibialis posterior tendon was included. Since flexor tendons at the wrist may show a high level of anisotropy making ultrasound evaluation of tendon damage difficult, they were not included in the ultrasound evaluation.
Ultrasonography. Bilateral ultrasound investigation was performed with six Esaote ultrasound scanners (one Mylab 70 XVision and five Mylab Class C; Esaote, Genoa, Italy) by means of linear array transducers (6–18 MHz or 4–13 MHz). The B mode settings of each ultrasound machine were optimised and fixed. Dynamic investigation by flexion and extension of particular fingers was allowed to improve differentiation of tendon pathologies.
The 12 ultrasonographers independently, consecutively and blinded to the clinical data performed the ultrasound examination of the selected tendons and assessed tendon damage in B mode according to the agreed scoring system. The extensor tendons of the wrist were scanned from the level of Lister's tubercle downwards to the level of the extensor retinaculum; the tibialis posterior tendon was scanned from a level proximal to the medial malleolus to slightly distal of it. Maximal scanning time was 15 min per patient. The scanning time included the time to fill out the scoring sheet.
All members of the OMERACT US task group collected images which were used to develop an US reference image atlas of tenosynovitis and tendon damage.
Statistical analysis was performed with the software package SPSS, version 17.0. Normally distributed continuous data were summarised with means and SDs or 95% CIs; non-normally distributed data were summarised with median and range.
Intra- and interobserver agreement was assessed by κ coefficients. Cohen's κ coefficient was calculated for intraobserver agreement, whereas Light's κ was calculated for interobserver agreement. The comparison of the κs between first and second occasion was conducted using the Root Mean Square Difference index, and by the product-moment correlation coefficient. Basic statistics and interobserver reliability represented by the intraclass correlation coefficient (ICC) with 95% CI were determined for each tendon compartment separately.
ICC and κ values are comparable; κ values were interpreted as follows: 0–0.20 poor, 0.20–0.40 fair, 0.40–0.60 moderate, 0.60–0.80 good and 0.80–1 excellent agreement.
Patients and Methods
A Two-step Study
The study was carried out in two steps. The first step consisted of a Delphi exercise, aiming to find agreement on ultrasound definitions of normal tendons, peritendinous structures, tenosynovitis and tendon damage in RA; furthermore, the Delphi exercise was done to reach consensus on the ultrasound grading of tenosynovitis and tendon damage in RA patients. Details on the methodology of the first step have previously been reported by Naredo et al.
Ultrasound Reliability Assessment
The first step of the study was followed by a two-day patient-reliability exercise, which took place in Amsterdam, The Netherlands. Each day was divided in a morning and an afternoon session. The afternoon session was a repetition of the morning session in order to assess the intraobserver reliability.
Patients. Twelve patients with RA according to the American College of Rheumatology 1987 criteria representing all degrees of disease activity (severe, moderate, low and remission as defined by DAS28) were recruited from the outpatient rheumatology clinic (MC Groep hospitals). Demographic and clinical data were recorded for all patients.
The 12 patients were equally divided over 2 days. Both wrists and ankles were studied for the ultrasound investigation. All patients were assessed twice, that is, during the morning and again in the afternoon. The local ethics committee approved the study and all patients gave written consent according to the Declaration of Helsinki.
Ultrasonographers. Twelve rheumatologists with extensive experience in ultrasound, that is, more than 10 years, participated in the present study.
Tendons. At the wrist, the following extensor tendons enclosed in a synovial sheath were selected: the second extensor compartment, that is, the extensor carpi radialis brevis and longus; the third, that is, the extensor pollicis longus (EPL); the fourth, that is, the extensor digitorum communis (EDC); the fifth, that is, the extensor digiti minimi (EDM); and the sixth, the extensor carpi ulnaris (ECU). At the ankle, the tibialis posterior tendon was included. Since flexor tendons at the wrist may show a high level of anisotropy making ultrasound evaluation of tendon damage difficult, they were not included in the ultrasound evaluation.
Ultrasonography. Bilateral ultrasound investigation was performed with six Esaote ultrasound scanners (one Mylab 70 XVision and five Mylab Class C; Esaote, Genoa, Italy) by means of linear array transducers (6–18 MHz or 4–13 MHz). The B mode settings of each ultrasound machine were optimised and fixed. Dynamic investigation by flexion and extension of particular fingers was allowed to improve differentiation of tendon pathologies.
The 12 ultrasonographers independently, consecutively and blinded to the clinical data performed the ultrasound examination of the selected tendons and assessed tendon damage in B mode according to the agreed scoring system. The extensor tendons of the wrist were scanned from the level of Lister's tubercle downwards to the level of the extensor retinaculum; the tibialis posterior tendon was scanned from a level proximal to the medial malleolus to slightly distal of it. Maximal scanning time was 15 min per patient. The scanning time included the time to fill out the scoring sheet.
Atlas
All members of the OMERACT US task group collected images which were used to develop an US reference image atlas of tenosynovitis and tendon damage.
Statistical Analysis
Statistical analysis was performed with the software package SPSS, version 17.0. Normally distributed continuous data were summarised with means and SDs or 95% CIs; non-normally distributed data were summarised with median and range.
Intra- and interobserver agreement was assessed by κ coefficients. Cohen's κ coefficient was calculated for intraobserver agreement, whereas Light's κ was calculated for interobserver agreement. The comparison of the κs between first and second occasion was conducted using the Root Mean Square Difference index, and by the product-moment correlation coefficient. Basic statistics and interobserver reliability represented by the intraclass correlation coefficient (ICC) with 95% CI were determined for each tendon compartment separately.
ICC and κ values are comparable; κ values were interpreted as follows: 0–0.20 poor, 0.20–0.40 fair, 0.40–0.60 moderate, 0.60–0.80 good and 0.80–1 excellent agreement.
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