421
global synovitis scoring system that combines grayscale synovial hypertrophy and
power Doppler (PD) in one. Its responsiveness has been tested in one international
multicenter open-label medication trial. It has the advantage that it can be performed
á la carte [ 11 ].
Although tenosynovitis is a common manifestation in RA and was reported to be
an early marker of the disease, it received much less attention by the scientifi c com-
munity than joint synovitis [ 12 ]. There is evidence that MSUS-detected tenosynovi-
tis is more sensitive than physical examination [ 13 ], it is responsive to effective
treatment [ 14 , 15 ], and that its persistence, namely extensor carpi ulnaris tenosyno-
vitis, predicts structural bone damage [ 16 ]. Tenosynovitis is defi ned as a hypoechoic
or anechoic thickened tissue with or without fl uid within the tendon sheath, which
is seen in two perpendicular plains and that may exhibit Doppler signal [ 5 ].
Quantitative assessment of tenosynovitis in RA patients was studied by the single
multi-expert-examiner consensus exercise [ 17 ]. Results revealed a good reproduc-
ibility using a semiquantitative scoring system based on the extension of Doppler
signal within the widened synovial sheath (excluding the feeding blood supply
Doppler signal). The scoring system rated from: 0 = no Doppler signal, 1 = periten-
dinous focal signal within the widened synovial sheath, 2 = peritendinous multifocal
signal within the widened synovial sheath, and 3 = peritendinous diffuse signal
within the widened synovial sheath. If abnormal intra-tendinous signal existed in
two perpendicular planes, then grades 1 and 2 are increased by one point.
Structural Damage
Structural MSUS joint disorders include intra-articular erosions, synovial-tendon
damage, as well as cartilage changes. Bone erosions are a destructive consequence
of synovitis and osteitis. A MSUS-detected erosion is defi ned as a cortical break
seen in two perpendicular planes [ 5 ]. When compared with radiography, MSUS
detects more erosions in the hand, shoulder, and feet [ 18 – 21 ]. This is attributed to
the fact that MSUS examination is multi-planer whereas radiography is two-
dimensional. However, MSUS-detected erosion is determined by the size of the
acoustic window. In routine clinical practice, MSUS-erosions are searched for diag-
nostic purposes and ongoing damage at specifi c sites in RA (distal ulna, second to
fi fth metacarpophalangeal [MCP] head, and fi fth metatarsophalangeal [MTP] head)
[ 22 ]. Doppler signal within an erosion probably signifi es ongoing bone damage [ 23 ]
and is often called a hot or active erosion. MSUS-erosions ≥ 2.5 mm are highly
sensitive and more specifi c for RA than those ≤ 2 mm that may be visualized in
normal individuals or in degenerative joint disorders [ 22 ]. Currently there is no
recommended erosion scoring system.
The natural history of synovial-tendon damage in RA is unclear. It has been sug-
gested that synovitis produces internal tendon damage leading to partial and ulti-
mately complete tendon tear. Unfortunately, physical examination is unable to
detect tendon structural damage until the tendon is totally torn exhibiting loss of
18 PROMs and Musculoskeletal Ultrasonography