{
 "serie": "s501_DP_SPAIR_TRA",
 "n_imgs": 24,
 "s": 52.2,
 "respuesta": "**Series:** Axial PD SPAIR (fat‑suppressed, fluid‑sensitive), right ankle, ordered distal (midfoot) → proximal (distal tibia). Image left = lateral (fibula), image right = medial, top = dorsal/anterior.\n\n**FINDINGS**\n\n**Joint fluid / synovium**\n- Tibiotalar joint effusion: fluid distending the anterior tibiotalar recess and lining the anterior talar dome (slices 14–19), with fluid also in the posterior recess behind the talus (slices 14–15). Moderate volume, more than physiologic. Some intermediate-signal thickening along the anterior joint line is suggestive of synovitis/scar at the site of prior anterior osteophyte resection. – Confidence: high (effusion), medium (synovitis).\n- Subtalar / sinus tarsi: increased fluid/edema signal in the sinus tarsi and lateral posterior subtalar joint (slices 12–14), lateral to the talar neck/calcaneus. – Confidence: medium.\n\n**Tendons**\n- Peroneal tendons: fluid surrounding the peroneal tendons in the retromalleolar and inframalleolar groove (posterolateral, slices 13–17) – peroneal tenosynovitis. The tendons themselves are difficult to fully separate on these slices; a subtle cleft raises the possibility of a peroneus brevis split, but this cannot be confirmed here. – Confidence: medium-high (tenosynovitis), low (split tear).\n- Flexor hallucis longus: fluid around the FHL at the posteromedial talus/posterior ankle (slices 14–16), more than expected for a joint that communicates; mild FHL tenosynovitis. – Confidence: medium.\n- Medial midfoot/plantar (slices 4–9): elongated bright fluid along a flexor tendon on the medial plantar side of the midfoot (region of FHL/FDL crossing – knot of Henry), consistent with tenosynovial fluid extending distally. Adjacent bright dots are the medial plantar vessels (normal). – Confidence: medium-low.\n- Tibialis posterior, FDL: normal caliber, no significant sheath fluid. Achilles tendon: normal thickness and low signal; Kager fat pad clear. – Normal.\n\n**Bones / marrow**\n- Small focus of increased marrow signal in the talar head/navicular region (slice 11, central, dorsal) – possible small subchondral cyst or focal marrow edema. – Confidence: low-medium.\n- Distal anterior tibial margin (slices 18–19): mildly irregular anterior tibial contour with adjacent fluid, compatible with post-surgical change/residual anterior spurring; no definite marrow edema. – Confidence: medium.\n- No fracture, no talar dome osteochondral lesion confidently identified on this series (cartilage assessment limited on axial SPAIR). No significant marrow edema in talus, calcaneus, tibia or fibula. – Medium.\n\n**Ligaments**\n- Anterior talofibular ligament region (slice 17, lateral, between fibula and talus): intermediate-signal thickening rather than a discrete taut low-signal band, favoring chronic thickened/scarred ATFL from the remote sprain. – Confidence: low-medium.\n- Deltoid and syndesmotic ligaments: no definite abnormality seen on these slices. – Low confidence (partially imaged).\n\n**Soft tissues**\n- Retrocalcaneal region (slice 13): small amount of bright signal at the posterosuperior calcaneus, possible minimal retrocalcaneal bursal fluid. – Confidence: low.\n- No soft tissue mass, no cellulitis; subcutaneous fat normal.\n\n**IMPRESSION**\n1. Moderate tibiotalar effusion with probable anterior synovitis/scar at the prior arthroscopy site.\n2. Peroneal tenosynovitis (possible brevis split, not confirmed); mild FHL tenosynovitis extending toward the midfoot.\n3. Sinus tarsi fluid/edema suggesting subtalar involvement / sinus tarsi syndrome.\n4. Chronic thickened ATFL (post-sprain); no acute ligament tear seen.\n5. Questionable small talar head/navicular subchondral cyst."
}