{
 "serie": "s301_T1_TSE_SAG.",
 "n_imgs": 18,
 "s": 47.5,
 "respuesta": "**Right ankle MRI – Sagittal T1 TSE (18 representative slices, medial → lateral)**\n\n**Technical note:** T1-weighted only; marrow oedema, effusion and ligament oedema are poorly characterised on this sequence and should be correlated with the fluid-sensitive series.\n\n---\n\n### Bones / joints\n\n1. **Anterior tibiotalar joint – post-arthroscopic/impingement changes (medium confidence)**\n - Location: anterior lip of the distal tibia and dorsal talar neck, midline slices (~8–12).\n - The anterior tibial margin is mildly irregular/blunted with a small residual/recurrent anterior beak, and there is a small dorsal talar neck prominence opposing it. Consistent with the known prior osteophyte resection with residual/recurrent anterior osseous impingement. No loose fragment is confidently identified on these slices.\n\n2. **Anterior joint recess soft tissue (medium confidence)**\n - Intermediate T1 signal tissue fills the anterior tibiotalar recess and extends over the dorsal talar neck (slices ~9–11), replacing the normally bright fat. This is compatible with anterior capsular thickening/synovial scarring (soft-tissue anterior impingement) – expected after arthroscopy, but may be symptomatic. Cannot separate from effusion on T1.\n\n3. **Sinus tarsi / subtalar region (low–medium confidence)**\n - On the lateral slices (~12–13) the fat of the sinus tarsi/tarsal canal appears partially replaced by low–intermediate T1 signal, and the posterior subtalar facet shows mild subchondral irregularity of the lateral talar process. Possibilities include sinus tarsi scarring (prior sprain) and early subtalar degenerative change. Correlate with STIR/PD-FS.\n\n4. **Talar dome cartilage/subchondral bone (low confidence)**\n - The medial and central talar dome (slices 8–10) shows preserved contour and homogeneous marrow. No definite osteochondral lesion or subchondral cyst is identified on T1; a small lesion cannot be excluded on this sequence alone.\n\n5. **Distal fibula (low confidence)**\n - The lateral malleolar tip (slices 15–17) shows slightly heterogeneous marrow with a linear low-signal band; this most likely reflects partial-volume averaging of the cortex/ligament attachments, but a remote healed avulsion at the ATFL/CFL origin cannot be excluded. No acute fracture line.\n\n6. **Other bones:** Tibial shaft, calcaneus (including posterosuperior tuberosity – no Haglund deformity), navicular, cuneiforms, cuboid and visible metatarsals/hallux show normal marrow signal and alignment. No os trigonum or posterior talar process abnormality confidently seen. Plantar calcaneal spur not seen.\n\n### Tendons\n- **Achilles tendon:** normal calibre, uniformly low signal, normal insertion; Kager's fat pad normal. No retrocalcaneal bursitis appreciable on T1.\n- **Posterior tibial, FDL, FHL (medial slices 4–7):** normal calibre and signal.\n- **Peroneal tendons (lateral slices 14–15):** normal course posterior to the fibula, no thickening or split visible.\n- **Anterior extensor tendons:** normal.\n\n### Ligaments\n- Sagittal T1 is not optimal for the lateral collateral complex; the posterior talofibular and posterior tibiofibular ligaments appear intact where visualised. Spring ligament/plantar fascia region appears normal. ATFL/CFL not assessable on this series.\n\n### Plantar soft tissues\n- Plantar fascia of normal thickness at the calcaneal origin. Plantar fat pad and intrinsic musculature normal. No soft-tissue mass.\n\n---\n\n### Impression\n1. Post-arthroscopic changes of the anterior ankle with residual/recurrent anterior tibial and dorsal talar neck osseous prominence and intermediate-signal soft tissue in the anterior recess – findings suggestive of anterior (osseous + soft-tissue) impingement (medium confidence).\n2. Possible sinus tarsi fat replacement/scarring and mild posterior subtalar subchondral irregularity (low–medium confidence) – correlate with fluid-sensitive sequences.\n3. No definite talar dome osteochondral lesion, tendon tear or fracture on this T1 series."
}