Image acquisition protocol for metacarpophalangeal joint analysis in inflammatory arthritis using high-resolution peripheral quantitative computed tomography.
| Acquisition parameters | Manufacturer recommends standard clinical acquisition measures (82 μm, 60 kVp, 900 μA, 100 ms) with daily quality-control calibrations. |
| Patient positioning | Optimal immobilization necessary to acquire high-quality images suitable for analysis. |
| Image quality for analysis | Use the manufacturer’s grading scale and include images graded 1–3. |
| Scout view | The minimal length of the scout view should include imaging of the 2nd and 3rd MCP joint spaces, with at least 3 mm on either side of the joint space to ensure adequate assessment of joint positioning and land marking. |
| Joints | At a minimum both the 2nd and 3rd MCP should be imaged. |
| Hand | If only unilateral images are acquired, then the dominant hand should be scanned unless the person has had a fracture in that arm in the last year and/or they have had any surgery in the area to be scanned. |
| Position | The MCP are to be positioned between 0° and 15° of flexion, consistent with current clinical radiographic imaging positioning of the MCP joints. |
| Reference line | The initial reference line for the scout view should be the midpoint of the concave articular surface of the base of the 2nd or 3rd proximal phalanx, whichever is the most distal. The scan should start at a minimum 2 mm distal to this line and should include a minimun of 2 stacks (∼220 slices) to ensure that both the 2nd and 3rd MCP joint spaces are contained fully within the first 110 slices, in an effort to avoid any potential effect of stack artifact or discontinuity in the joint space. If a 3rd stack (∼330 slices) can also be done, the scan start location can be located more distally if needed, but it should still be ensured that the 2nd and 3rd MCP joint spaces are fully contained within 1 stack. |
| Reproducibility/precision | Investigators should report a measure of reliability (e.g., RMSCV, LSC) for their evaluations. |
MCP: metacarpophalangeal; RMSCV: root square mean coefficient of variance; LSC: least significant change.