{
 "serie": "s4_SAG_PD_FS",
 "n_imgs": 16,
 "s": 57.4,
 "respuesta": "**Sagittal PD FS, right ankle – ordered medial (slices 1–5) → lateral (slices 13–16)**\n\n**Joints / fluid**\n1. **Tibiotalar joint effusion** – moderate; fluid distends the anterior and posterior capsular recesses (slices 8–12), most conspicuous posteriorly where fluid tracks along the posterior tibial margin. Confidence: high.\n2. **Posterior ankle recess – heterogeneous/irregular fluid signal** behind the posterior talar process (slices 11–12), with a nodular, slightly irregular appearance suggesting synovitis ± small intra-articular bodies / posterior impingement-type change. Confidence: medium.\n3. **Posterior subtalar joint** – fluid in the joint with irregular, dotted bright subchondral signal along the talar posterior facet and superior calcaneus (slices 10–12), consistent with degenerative change with small subchondral cysts / focal marrow reaction; possible small intra-articular bodies. Confidence: medium.\n4. **Sinus tarsi** – normal fat signal is replaced by diffuse high signal (slices 12–13), in keeping with sinus tarsi edema/fluid (sinus tarsi syndrome pattern; interosseous ligament not clearly delineated). Confidence: medium.\n5. Small fluid in the talonavicular and midfoot joints (slices 7–9) – within normal to mildly increased. Confidence: low.\n\n**Bones**\n6. Small punctate high-signal focus in the central talar body (slice 8) – tiny subchondral cyst vs. vessel. Confidence: low.\n7. Subchondral cystic change/edema of the posterior subtalar facet of the talus and calcaneus as above (slices 10–12). Confidence: medium.\n8. No fracture line, no talar dome osteochondral defect with marrow edema confidently identified; distal tibia and fibula marrow otherwise normal. Calcaneal tuberosity/Achilles insertion without marrow edema.\n\n**Tendons**\n9. **Flexor hallucis longus** – thin curvilinear fluid along the tendon sheath posterior to the talus extending toward the plantar foot (slice 7), communicating with the effused joint; mild tenosynovitis vs. simple communication. Confidence: low–medium.\n10. **Peroneal tendons** – trace fluid along the sheath posterior/inferior to the lateral malleolus (slice 13). Confidence: low.\n11. Achilles tendon: normal thickness and signal; Kager fat pad clear; no retrocalcaneal bursitis. Posterior tibial tendon and anterior tendons appear intact on the available slices.\n\n**Ligaments**\n12. **Lateral ligament complex** – ill-defined high signal in the soft tissues anterior and inferior to the fibular tip (slices 13–14) at the expected ATFL/CFL region, suggesting sprain/periligamentous edema; ligament fibers not well seen on the sampled slices. Confidence: medium.\n13. Deltoid / spring ligament region (slices 5–6): mild surrounding edema, otherwise not well assessed; no clear discontinuity. Confidence: low.\n\n**Soft tissues**\n14. **Plantar heel fat pad and plantar fascia origin** – reticular high signal in the plantar heel fat and along the proximal plantar fascia (slices 6–9), suggesting fat pad edema / mild plantar fasciitis. Confidence: medium.\n15. **Diffuse subcutaneous edema** over the dorsum of the foot/ankle, the medial forefoot and lateral hindfoot (slices 1–5, 12–14). Peripheral portions (slices 1–5, 15–16) are partly degraded by incomplete fat suppression/coil fall-off, so the medial plantar high signal should be interpreted cautiously. Confidence: medium (edema) / high (partial artifact).\n16. Prominent tubular high signal medially (slice 5) most consistent with posterior tibial neurovascular bundle vessels rather than tendon pathology. Confidence: medium.\n\n**Summary:** Moderate tibiotalar effusion with posterior recess synovitis, degenerative posterior subtalar joint changes with subchondral cysts, sinus tarsi edema, probable lateral ligament sprain with lateral soft tissue edema, plantar heel fat pad/plantar fascia edema, and diffuse subcutaneous edema. Achilles and major tendons grossly intact; no fracture."
}