Table 1

Proposed definitions and scaling (category description) of HOA features included in the proposed OHOA-MRI score

DefinitionScoring
SynovitisAn area in the synovial compartment that shows post-Gd
enhancement* of a thickness greater than the width of normal
synovium (as shown in the atlas). *Enhancement (signal intensity
increased) is judged by comparison of T1w images obtained before
and after intravenous Gd contrast.
Synovitis is scored by thirds of the maximum potential volume
of enhancing tissue in the synovial compartment, where
0=normal, 1=mild, 2=moderate, 3=severe
Flexor tenosynovitisAn area in the flexor tendon sheath that shows post-Gd enhancement*
of a thickness greater than the normal width of the tendon sheath (as
shown in the atlas). *Enhancement is judged by comparison of T1w
images obtained before and after intravenous Gd contrast.
When measuring the maximal thickness of the tendon sheath with
Gd enhancement, tenosynovitis is scored as follows: 0=normal,
1=<0.5 tendon thickness,
2=≥0.5 and <1 tendon thickness, 3=≥1 tendon thickness
ErosionA sharply marginated bone lesion with typical signal characteristics*,
which is visible in two planes with a cortical break seen in at least one
plane. *Increased signal intensity in the area of cortical bone and bone
marrow fat on T1w fs images.
Distal and proximal part of the joint are scored separately,
as follows: 0=no erosion, 1=1–2 small erosion(s) and/
or subchondral bone collapse (‘seagull wing’), 2=moderate
erosion(s) or ≥3 small erosions
with total size as a moderate erosion, 3=large erosion(s) or several small/moderate erosions with total size as a large erosion
CystA sharply marginated bone lesion with typical signal characteristics*,
which is visible in two planes without a cortical break. *Increased signal
intensity of cortical bone and bone marrow fat on T1w fs images.
Distal and proximal part of the joint are scored separately, as
follows: 0=no cyst, 1=≥1 cyst(s)
Osteophyte (OP)Abnormal bone formation in the periarticular region on T1w fs images.Distal and proximal part of the joint separately are scored
separately, as follows: 0=no OP, 1=1–2 small OP, 2=≥3 small OP or moderate OP(s), 3=large OP(s)
Joint space narrowing (JSN)Narrowing of the joint width on T1w fs images0=no JSN, 1=mild JSN, 2=bone-to-bone contact in part of the joint, 3=bone-to bone contact in the whole joint
MalalignmentSubluxation/luxation of joints in either frontal (≥15°)
or sagittal plane (crossing the midline) on T1w fs images
Malalignment in the frontal and sagittal plane are
scored separately, as follows: 0=no malalignment, 1=malalignment
Bone marrow lesion (BML)A lesion* within the trabecular bone with signal characteristic consistent
with increased water content** and often with ill-defined margins.
*May occur alone or surrounding an erosion or other bone abnormalities. **High signal intensity on STIR images.
Scored as the proportion of bone with BML in
the distal and proximal part of the joint separately: 0=no BML,
1=1–33% of bone with BML, 2=34% to 66% of bone with BML, 3=67% to 100% of bone with BML
Collateral ligament (CL)(1) Absence of CL: non-visible or non-continuous CL on T1w fs images(2) BML at CL
insertion sites: a lesion within the trabecular bone at the CL
insertion sites with signal characteristics consistent with increased water content*
and often with ill-defined margins. *High signal on STIR images.
(1) Radial and ulnar part of the joint are scored separately, as follows:
0=visible CL, 1=non-visible CL(2) Radial and ulnar part of the distal and proximal
joint are scored separately, as follows: 0=no BML, 1=present BML(s) at CL insertion sites
  • fs, fat suppressed; Gd, gadolinium; HOA, hand osteoarthritis; OHOA-MRI, Oslo hand osteoarthritis MRI; STIR, Short T1 Inversion Recovery; T1w, T1-weighted.