{
 "serie": "s6_COR_2D_MERGE",
 "n_imgs": 22,
 "s": 96.4,
 "respuesta": "**Right ankle MRI – coronal 2D MERGE (22 images, anterior → posterior)**\n\nOrientation: fibula/lateral on image left, medial on image right. MERGE is a T2*‑weighted gradient‑echo sequence: articular cartilage and fluid are bright, marrow is dark, fat is intermediate‑to‑bright, so fluid vs. fat discrimination is imperfect and confidence is graded accordingly.\n\n**Joints / fluid**\n1. Tibiotalar joint – small effusion. Fluid is seen in the anterior recess (slices 5–7), in the medial and lateral gutters (slices 7–10, lateral gutter between talus and distal fibula slice 7), and in the posterior capsular recess above the posterior talus/calcaneus (bright foci on slices 13–17). Confidence: medium.\n2. Distal tibiofibular (syndesmotic) recess – a thin bright line extending superiorly between tibia and fibula on slices 10–11; likely physiologic recess fluid, no convincing widening. Confidence: low.\n3. Posterior subtalar joint – prominent bright fluid line (slices 9–12) suggesting a small subtalar effusion. Confidence: low‑medium.\n\n**Cartilage / bone**\n4. Medial talar dome – small focal bright signal at the medial corner of the dome/subjacent subchondral bone (slices 6, 9–10), raising concern for a small chondral/early osteochondral lesion (common post‑sprain). No overt fragment or cystic change. Confidence: low.\n5. Calcaneal body – mottled heterogeneous marrow signal in the inferior/central body (slices 11–12); most likely normal trabecular pattern on GRE rather than edema (no correlative fluid‑sensitive sequence). Confidence: low.\n6. Remaining bones (tibia, fibula, talus otherwise, navicular, cuneiforms): no fracture line, no cyst, no cortical irregularity. Talonavicular and midfoot cartilage appears intact (slices 1–4).\n\n**Ligaments**\n7. Lateral ligament complex – the coronal plane does not profile the ATFL well; the presence of lateral gutter fluid and remote sprain history suggests chronic ATFL insufficiency, but this cannot be confirmed here. CFL region beneath the peroneal tendons (slices 6–8) shows no discrete abnormality. Confidence: low.\n8. Deltoid ligament – deep deltoid fibres between medial malleolus and medial talus (slices 8–10) appear slightly heterogeneous/striated with interposed bright signal, compatible with chronic sprain/scarring rather than acute tear. Confidence: low.\n9. Sinus tarsi / interosseous talocalcaneal ligament (slices 6–8) – fat preserved, ligament visible; no obliteration. Normal.\n\n**Tendons**\n10. Peroneal tendons – lateral to calcaneus below fibular tip (slices 7–9): small rim of fluid around the tendons suggesting mild tenosynovitis; tendons themselves appear intact, no split. Confidence: low‑medium.\n11. Medial flexor tendons (tibialis posterior / FDL) – rounded dark tendons with a thin bright fluid halo on slices 9–11; mild tendon‑sheath fluid, possibly physiologic (communicates with joint). Confidence: low.\n12. Flexor hallucis longus – discrete bright foci posteromedial to the talus/above the calcaneus (slices 14–17) could represent FHL tendon‑sheath fluid rather than only posterior recess fluid. Confidence: low.\n13. Achilles tendon (slices 17–20) – normal thickness and low signal; retrocalcaneal bursa not distended. Normal.\n14. Anterior tibial/extensor tendons (slices 1–5) – no abnormality identified.\n\n**Soft tissues**\n15. Heel fat pad, plantar fascia origin and subcutaneous tissues – normal; no mass, no plantar fasciitis, no ganglion identified. A bright rounded structure along the medial/plantar aspect (slices 2–5) is most consistent with lobulated fat rather than a cyst. Confidence: low.\n\n**Impression**\nSmall tibiotalar (and probable subtalar) effusion with fluid in the gutters and posterior recess; mild peroneal ± medial flexor tendon‑sheath fluid; equivocal small focal chondral irregularity of the medial talar dome and mild deep‑deltoid heterogeneity, in keeping with sequelae of remote ankle sprain. No fracture, osteochondral fragment, tendon tear or mass. Correlation with the axial/sagittal fluid‑sensitive sequences is recommended to confirm ligament integrity and any talar dome lesion."
}