Ultrasonographic image acquisition protocol for frequently affected joints in juvenile idiopathic arthritis
| Regions | Image acquisition protocol |
| General remarks | The scanning will be done bilaterally. The left side of the screen is proximal, the right side distal. The probe will be moved across the joint for the specified scans. Scoring of BM and PD should be done at the area of the maximal distension of the synovial recess and the maximum amount of PD while keeping the bony landmarks clearly in view. PD will only be done when the BM score is 1 or more. The Doppler box should be placed to cover the entire joint and extend to the top of the image to be aware of reverberation artefacts. |
| Anterior elbow | The subject will be in a supine position, but the scanning can also be done with the subject on the parents’ lap. The elbow should be in full extension and supination of the lower arm for a longitudinal anterior scan of the elbow (humeroradial) joint. Landmarks: (1) The distal humerus and (2) The radius |
| Posterior elbow | The subject will be in a supine position, but the scanning can also be done with the subject on the parents’ lap. The elbow should be flexed at 90 degrees with the forearm resting on the stomach. A longitudinal posterior scan of the elbow (humeroulnar) joint. Landmarks: (1) The distal humerus and (2) The olecranon (ulna) |
| Radiocarpal and midcarpal | The subject will be in a sitting position, the hands palm-side down in a neutral position on an examination table and resting the elbow on the table. A longitudinal dorsal scan of the radiocarpal and midcarpal joints at the sagittal midline of the wrist, including the distal radius, the lunate and the capitate bone. Landmarks: (1) The distal end of diaphysis and epiphysial cartilage of radius and (2) The dorsal recess of the radiocarpal and midcarpal joints and over them (3) A compartment of the extensor tendons according to the area imaged 13 |
| MCP2–3, dorsal | The subject will be in a sitting position with the hands palm-side down in a neutral position on an examination table. A longitudinal dorsal scan of the MCP2 and MCP3 joints. Landmarks: (1) The head of metacarpal bone (2/3 of the image) and (2) The base of proximal phalanx (1/3 of the image) |
| PIP2–3, dorsal | The subject will be in a sitting position with the hands palm-side down in a neutral position on an examination table. A longitudinal dorsal scan of the PIP2 and PIP3 joints. Landmarks: (1) The head of proximal phalanx (2/3 of the image) and (2) The base of middle phalanx (1/3 of the image) |
| PIP2–3, volar | The subject will be in a sitting position with the hands palm-side up in a neutral position on an examination table. A longitudinal volar scan of the PIP2 and PIP3 joints. Landmarks: (1) The head of the proximal phalanx, (2) The base of the middle phalanx and (3) The flexor tendon |
| Hip | The subject will be in a supine position with the hip in a neutral position, slightly externally rotated. A longitudinal anterior scan parallel to the femoral neck of the hip joint. Landmarks: (1) The femoral head and (2) The femoral neck. |
| Knee, suprapatellar recess | The subject will be in a supine position. The knee should be flexed at 30 degrees, and images taken after the subject completes flexion and extension three times. A longitudinal scan of the suprapatellar joint space. For the youngest subjects the patella should fill 1/3 of the image to compensate for the relatively shorter femur (to not underestimate the scoring). Landmarks: (1) The proximal third of the patella and (2) A clearly visualised quadriceps tendon 17 |
| Knee, lateral parapatellar recess | The subject will be in a supine position. The knee should be flexed at 30 degrees. For the lateral parapatellar recess the image will be obtained with the probe in transverse position over the mid-patella with both the patella and femur in view. Landmarks: (1) The superior edge of the patella and (2) The femoral condyle 17 |
| Tibiotalar | The subject will be in a supine position with the knee at 90 degrees flexion and the foot sole-side down. A longitudinal scan of the tibiotalar joint. Landmarks: (1) The distal end of the tibia and (2) The talus |
| Talonavicular | The subject will be in a supine position with the knee at 90 degrees flexion and the foot sole-side down. A longitudinal scan of the talonavicular joint. Landmarks: (1) The talus and (2) The navicular bone |
| Anterior subtalar | The subject will be in a supine position with the forefoot/ankle in slight eversion. The probe will be positioned at 45 degrees pointing to the heel and then moved proximally and distally. A medial scan of the anterior subtalar joint. Landmarks: (1) The talus and (2) The sustentaculum tali (calcaneus) |
| Posterior subtalar | The subject will be in a supine position with the forefoot/ankle in slight inversion. The probe will be positioned along the sinus tarsi perpendicular to the sole, and then moved posteriorly. If no distension is seen, the image will be taken visualising the joint with the peroneus tendons. A lateral scan of the posterior subtalar joint. Landmarks: (1) The talus and (2) The calcaneus |
| MTP2–3 dorsal | The subject will be in a supine position with the knee at 90 degrees flexion and the foot sole-side down. A longitudinal dorsal scan of the MTP2 and MTP3 joints. Landmarks: (1) The head of metatarsal bone (2/3 or the image) and (2) The base of the proximal phalanx (1/3 of the image) |
BM, B-mode; MCP, metacarpophalangeal; MTP, metatarsophalangeal; PD, power Doppler; PIP, proximal interphalangeal.