{
 "serie": "s301_T1_TSE_SAG.",
 "n_imgs": 18,
 "s": 50.3,
 "respuesta": "**Series:** Sagittal T1 TSE, right ankle/foot, slices ordered medial → lateral (hallux/sesamoids on first images, fibula/lateral malleolus on last images). The lateral‑most 3–4 slices are largely outside the coil sensitivity region and are non‑diagnostic.\n\n**Abnormal / potentially abnormal findings**\n\n1. **Tibiotalar joint – small posterior/anterior recess distension (effusion/synovitis)** – slices 9–12: intermediate‑to‑low T1 signal material distending the posterior recess between the posterior tibial plafond and the posterior talar dome/process, with mild capsular distension anteriorly as well. Confidence: medium (fluid vs synovial thickening cannot be separated on T1 alone).\n\n2. **Posterior talar process / os trigonum region** – slices 11–12: the posterior process of the talus appears prominent with a thin low‑signal cleft at its base, raising the question of an os trigonum/prominent Stieda process; no definite marrow signal alteration on T1. Confidence: low.\n\n3. **Sinus tarsi – partial replacement of normal fat signal** – slices 12–13: the normally bright fat in the sinus tarsi/tarsal canal is heterogeneous and partly replaced by intermediate/low T1 signal, suggesting sinus tarsi soft‑tissue infiltration (synovitis/scarring, \"sinus tarsi syndrome\" pattern). Interosseous talocalcaneal ligament not clearly delineated. Confidence: medium‑low (partial volume with the lateral talar process is possible).\n\n4. **Plantar fascia – mild proximal thickening** – slices 7–9: the central cord of the plantar fascia appears mildly thickened near its calcaneal origin, without a clear fluid‑equivalent gap or marrow signal change in the medial calcaneal tuberosity on T1. Confidence: low (fluid‑sensitive sequences needed to confirm fasciitis).\n\n5. **Lesser toe alignment** – slices 7–10: the lesser toes are held in a flexed/curled position (hammer/claw‑toe configuration). May be positional. Confidence: low‑medium.\n\n**Structures that appear normal (within limits of T1‑only assessment)**\n\n- Bone marrow: tibia, fibula, talus, calcaneus, navicular, cuneiforms, metatarsals show normal fatty marrow signal; no T1‑hypointense fracture line, marrow replacement or focal lesion identified. Talar dome subchondral bone appears intact (no definite osteochondral lesion). Confidence: high.\n- Achilles tendon: normal calibre and uniform low signal to its calcaneal insertion; Kager fat pad and retrocalcaneal region normal. Confidence: high.\n- Tibialis anterior, tibialis posterior, FDL, FHL and peroneal tendons: appear normally low signal and of normal calibre on the slices where visible, without peritendinous mass or gross tenosynovial thickening. Confidence: medium (partially imaged).\n- Subtalar (posterior facet) and talonavicular, naviculocuneiform and tarsometatarsal joints: congruent, no significant joint space narrowing or subchondral cyst formation. Confidence: medium.\n- Heel fat pad and plantar soft tissues: normal thickness and signal; no plantar calcaneal spur clearly seen. Confidence: medium.\n- First MTP joint and sesamoids: normal marrow signal and alignment. Confidence: medium.\n\n**Impression**\nPredominantly unremarkable T1 appearances of the osseous structures and tendons. Findings suggestive of mild tibiotalar joint distension (effusion/synovitis), possible sinus tarsi fat replacement, and a questionable os trigonum/prominent posterior talar process; mild proximal plantar fascial thickening is possible. These findings require correlation with fluid‑sensitive (PD/T2 FS or STIR) sequences for confirmation."
}