363.4 📋 章末速蚘 Summary

363.4.1 🔑 䞀句話瞜結

Neuroimaging + diagnostic procedures = systematic toolkit for neuro disease; CT (fast, widely available) for acute hemorrhage + trauma + bone + calcification (hyperdense acute blood, hypodense edema/infarct) + acute stroke initial screening (rule out bleed, ASPECTS); MRI definitive for most pathology — sequences include **T1 anatomy + T2 pathology bright + FLAIR (CSF-suppressed for MS/edema/periventricular) + DWI (acute stroke bright within minutes-hours, persists 1-2 weeks + abscess + hypercellular tumor) + T2*/SWI (microbleeds, hemosiderin, CAA, hypertensive microbleeds, cavernomas) + gadolinium (BBB disruption — tumor, abscess, demyelination, infection, active MS lesions, meningeal) + perfusion (CBF/CBV/MTT, penumbra DWI-perfusion mismatch) + MRA/MRV (vessels) + MRS (NAA/choline/creatine/lactate metabolites) + DTI (white matter tracts) + fMRI; vascular imaging — CTA + MRA + DSA gold standard + carotid Doppler + TCD (transcranial); EEG for seizures (3 Hz spike-wave absence, focal sharp, generalized spike-wave) + encephalopathy (triphasic = hepatic) + brain death (electrocerebral silence) + sleep + status epilepticus + post-arrest prognosis; continuous EEG (cEEG) in ICU detects non-convulsive status epilepticus (8-20% comatose); EMG + NCS distinguishes axonal (↓ amplitude) vs demyelinating (↓ conduction velocity, conduction block); repetitive nerve stimulation — decremental in MG, incremental post-exercise in LEMS; single-fiber EMG most sensitive NMJ; evoked potentials VEP/BAEP/SSEP/MEP for MS + prognosis; LP + CSF analysis indications include meningitis + encephalitis + SAH (CT-neg xanthochromia) + MS (oligoclonal bands + IgG index) + autoimmune (NMDA-R, LGI1) + malignancy cytology + IIH/NPH pressure; contraindications include ↑ ICP with mass effect (herniation risk — image first if focal signs/papilledema) + coagulopathy + infection at site; classic CSF patterns — bacterial ↑↑ PMN + ↑↑ protein + ↓ glucose, viral lymphs + mild protein + normal glucose, TB/fungal lymphs + ↑↑ protein + ↓ glucose, MS oligoclonal bands, GBS albuminocytologic dissociation, SAH RBCs + xanthochromia; emerging — amyloid/tau PET for Alzheimer therapy eligibility (lecanemab Leqembi, donanemab Kisunla), DaT-SCAN for parkinsonism, plasma biomarkers p-tau 217/Aβ42:40/GFAP/NfL, AI software (RapidAI, Viz.ai) in stroke workflow, mobile stroke units (B_PROUD 2021)**。

363.4.2 💊 治療粟芁

  • Modality choice: CT urgent (hemorrhage, trauma, fast); MRI definitive (most else, choose sequence for question)
  • Acute stroke workflow: CT + CTA + CT perfusion (or MRI DWI + MRA + perfusion); rule out bleed + identify LVO + assess penumbra
  • LP indications: meningitis + encephalitis + suspected SAH (CT-negative — xanthochromia in CSF) + MS workup + autoimmune + malignancy + IIH/NPH
  • LP contraindications: ↑ ICP with mass effect (image first if focal signs + papilledema + immunocompromised + altered LOC) + coagulopathy (correct) + infection at site
  • Gadolinium use: GFR > 30 (NSF risk in advanced CKD); pregnancy avoid if possible
  • EEG timing: continuous EEG in ICU for non-convulsive status epilepticus; standard 30 min for routine; brain death > 30 min
  • EMG timing: wait 2-3 weeks after onset for full denervation/reinnervation picture

363.4.3 🎯 盧醫垫的考前提醒

  1. CT vs MRI choice: CT for acute hemorrhage + trauma + bone + fast triage; MRI for most other pathology + better resolution + no radiation; CT often normal in first hours of stroke but DWI bright within minutes
  2. MRI sequences purpose (memorize): **T1 anatomy, T2 pathology bright, FLAIR for MS/edema (CSF suppressed), DWI for acute stroke (bright within minutes), T2*/SWI for microbleeds, gadolinium for BBB disruption (tumor/infection/active MS), MRA for vessels**
  3. DWI restricted diffusion differential: acute stroke (most common) + abscess center + epidermoid + hypercellular tumor (lymphoma) + status epilepticus
  4. Ring-enhancing lesions (MAGIC DR): Metastasis + Abscess + Glioblastoma + Infection (toxoplasmosis) + Contusion + Demyelinating (tumefactive MS) + Radiation necrosis
  5. EEG patterns: 3 Hz spike-wave = absence; periodic lateralized epileptiform discharges (PLEDs) = focal lesion + HSV; burst suppression = deep anesthesia/coma; triphasic waves = hepatic/metabolic encephalopathy; electrocerebral silence = brain death
  6. EMG/NCS distinction: axonal = ↓ amplitude (CMT2, diabetic, axonal GBS variant) vs demyelinating = ↓ conduction velocity + conduction block (CIDP, classic GBS, CMT1)
  7. Repetitive nerve stimulation: decremental response = myasthenia gravis (postsynaptic) vs incremental response after exercise = Lambert-Eaton (LEMS, presynaptic)
  8. CSF patterns (memorize all): bacterial = ↑↑ PMN + ↓ glucose; viral = lymphs + normal glucose; TB/fungal = lymphs + ↓ glucose + ↑↑ protein; MS = oligoclonal bands + IgG index; GBS = albuminocytologic dissociation; SAH = RBCs + xanthochromia
  9. LP precautions: image first if focal signs + papilledema + immunocompromised + altered LOC + recent seizure + age > 60; correct coagulopathy
  10. Emerging tools 2024-2026: amyloid + tau PET for Alzheimer anti-amyloid therapy eligibility (lecanemab, donanemab); DaT-SCAN for parkinsonism vs essential tremor; plasma p-tau 217 + Aβ42:40 + GFAP + NfL less invasive biomarkers; AI software (RapidAI, Viz.ai) in stroke workflow; mobile stroke units with CT scanner