{
 "serie": "s5_SAG_T1_memp",
 "n_imgs": 16,
 "s": 47.7,
 "respuesta": "**Series: Sagittal T1, right ankle (lateral → medial)**\n\n**Bones / marrow**\n- Posterior talar process (slices 9–10): a small separate ossicle posterior to the talar body separated by a thin low‑signal cleft – consistent with an os trigonum (or non‑united posterior process/Stieda fragment). The synchondrosis region and adjacent posterior recess show intermediate/low T1 signal rather than fat, raising concern for posterior ankle (os trigonum) impingement / synchondrosis stress. Confidence: medium.\n- Anterior distal tibial lip (slices 10–11) appears mildly prominent/beaked, suggesting a small anterior tibial osteophyte (anterior impingement spur). Confidence: low.\n- Talar dome, tibial plafond, calcaneus, navicular, cuboid, cuneiforms and metatarsal bases: marrow signal normal, no fracture line or definite osteochondral lesion identified (T1 only; fluid‑sensitive sequence needed to exclude bone marrow edema). Heterogeneous distal fibular/tibial metaphyseal marrow is within normal red‑marrow range.\n\n**Joints / fluid**\n- Tibiotalar joint (slices 8–11): distension of the anterior and posterior joint recesses with low‑to‑intermediate T1 material – small–moderate joint effusion and/or synovitis. The anterior recess soft tissue (anterior to talar neck) is intermediate signal and slightly bulky, possibly capsular thickening/scar. Confidence: medium.\n- Posterior subtalar and talonavicular joints: no gross malalignment; cartilage not well assessed on T1.\n\n**Ligaments**\n- Sinus tarsi (slices 7–8): fat signal is partially replaced by intermediate signal strands around the interosseous/cervical ligaments – possible sinus tarsi inflammation/scarring. Confidence: low.\n- Lateral collateral ligaments and deltoid: limited assessment on sagittal T1; no discrete disruption seen.\n\n**Tendons**\n- Achilles tendon: normal thickness and uniform low signal; retrocalcaneal region and Kager fat pad normal.\n- Peroneal, posterior tibial, FDL and FHL tendons: normal caliber and signal on the imaged slices; no tenosynovial fluid appreciable on T1.\n- Plantar fascia: normal thickness at the calcaneal origin.\n\n**Soft tissues**\n- Subcutaneous fat and musculature normal; no mass or collection.\n\n**Summary**\n1. Os trigonum / posterior talar process ossicle with abnormal signal at the synchondrosis and posterior recess – suspicious for posterior impingement (medium).\n2. Tibiotalar joint effusion / synovitis, anterior recess capsular thickening (medium).\n3. Possible small anterior tibial osteophyte (low) and possible sinus tarsi changes (low).\nNo tendon tear, fracture or osteochondral defect identified on this sequence; correlation with fluid‑sensitive sequences recommended."
}