{
 "serie": "s501_DP_SPAIR_TRA",
 "n_imgs": 24,
 "s": 50.6,
 "respuesta": "**Series:** Axial PD SPAIR (fat‑suppressed, fluid‑sensitive), right ankle, slices ordered distal (midfoot) → proximal (distal tibia/fibula). Anterior at top; lateral (fibula) at viewer's left, medial at viewer's right.\n\n**Abnormal findings**\n\n1. **Tibiotalar (ankle) joint effusion / synovitis** – Bright fluid distending the anterior joint recess between distal tibia and talar dome (slices 17–20, most conspicuous on slice 19), with fluid also tracking into the anterolateral gutter and the posterior recess. Moderate volume. Confidence: **high**.\n\n2. **Flexor hallucis longus tenosynovitis** – Fluid surrounding the FHL tendon behind the posterior talus/sustentaculum (slices 13–16), continuing distally along the plantar‑medial hindfoot/midfoot where a linear fluid collection tracks along the flexor tendons toward the knot of Henry (slices 6–11, medial/plantar side). Fluid volume exceeds what would be expected from simple communication with the joint. Confidence: **high** (posterior ankle), **medium** (midfoot extension – FHL vs FDL sheath).\n\n3. **Medial (posterior tibial / flexor digitorum longus) tendon sheath fluid** – Rim of fluid around the medial tendons posterior to the medial malleolus/distal tibia (slices 20–24). Tendons themselves appear intact and of normal caliber. Confidence: **medium**.\n\n4. **Peroneal tenosynovitis** – Fluid surrounding the peroneal tendons at and just below the lateral calcaneal wall and retromalleolar groove (slices 13–19). No clear split or tendon enlargement on these images. Confidence: **medium‑high**.\n\n5. **Subtalar / talocalcaneal joint fluid and sinus tarsi signal** – Fluid in the posterior subtalar joint and increased fluid signal within the sinus tarsi (slices 13–16). Interosseous ligament not clearly resolvable on this plane. Confidence: **medium**.\n\n6. **Anterior extensor tendon sheath fluid** – Small dots of fluid around the anterior compartment tendons (tibialis anterior/EHL) on slices 21–24; minor, likely reactive. Confidence: **low‑medium**.\n\n7. **Focal bright marrow/cyst‑like signal, anterior calcaneus/cuboid region** – Small ovoid bright focus within the lateral midfoot bone on slice 11 (and faintly slice 10). Could represent a small subchondral cyst/marrow edema at the calcaneocuboid joint or partial volume of joint fluid. Confidence: **low**.\n\n8. **Diffuse increased signal in the plantar/forefoot subcutaneous fat** (slices 1–5) – Most likely incomplete fat suppression at the periphery of the field of view, but mild subcutaneous edema cannot be excluded. Confidence: **low**.\n\n**Structures that appear normal**\n- Achilles tendon: normal thickness and uniformly low signal at all levels; Kager's fat pad and retrocalcaneal region without edema or bursal fluid.\n- Bone marrow of talus, calcaneal body, distal tibia and fibula: no marrow edema, fracture line or osteochondral lesion identified on the sampled slices.\n- No obvious osseous destruction or soft‑tissue mass.\n- Plantar fascia (where seen) appears normal.\n\n**Impression:** Ankle joint effusion with synovitis, FHL and medial flexor tenosynovitis, peroneal tenosynovitis and subtalar/sinus tarsi fluid – a pattern of diffuse periarticular synovitis/tenosynovitis without focal bone marrow abnormality. Correlate with T1 and sagittal/coronal series for ligament integrity and any subtle osteochondral lesion."
}