{
  "version": "v4.0",
  "source": "WHO CNS 2021 + GBM literature",
  "n_chunks": 40,
  "embedder": "sentence-transformers/all-MiniLM-L6-v2",
  "embed_dim": 384,
  "top_k": 4,
  "min_score": 0.1,
  "chunks": [
    "Glioblastoma IDH-wildtype WHO grade 4: characterized by microvascular proliferation, necrosis, and EGFR amplification. Median OS 15 months with TMZ+RT (Stupp protocol).",
    "GBM ring-enhancing lesion on T1c MRI with central necrosis (T1 hypointense, T2 hyperintense). Surrounding FLAIR hyperintensity represents vasogenic edema and infiltration.",
    "Gross Total Resection (GTR) of GBM improves progression-free survival. MGMT promoter methylation (30-40% of GBM) predicts favorable response to temozolomide.",
    "MGMT methylated GBM: 2-year survival 26% with TMZ+RT. MGMT unmethylated: consider intensified RT, CCNU, or clinical trials.",
    "GBM recurrence: bevacizumab reduces edema and contrast enhancement; limited OS benefit. Tumor treating fields (TTF) approved for recurrent GBM.",
    "IDH-wildtype GBM molecular markers: EGFR amplification, chromosome 7 gain/10 loss, TERT promoter mutation (72%). CDKN2A/B deletion in 50%.",
    "WHO 2021 GBM criteria: IDH-wildtype diffuse astrocytoma with EGFR amplification OR +7/-10 OR TERT promoter mutation = GBM regardless of histology.",
    "IDH-mutant astrocytoma WHO grade 2-4: better prognosis than IDH-wildtype. Grade 4 requires CDKN2A/B homozygous deletion for diagnosis.",
    "IDH-mutant grade 4 astrocytoma: median OS 3-4 years. Treatment: maximal resection + RT + TMZ. MGMT methylation frequent (>60%).",
    "Oligodendroglioma IDH-mutant 1p/19q-codeleted WHO grade 2-3: favorable prognosis (OS 10-15 years grade 2). Chemosensitive to PCV.",
    "WHO CNS 2021 integrates molecular markers: IDH1/2, TERT promoter, EGFR, chromosome 7/10, 1p/19q codeletion for glioma classification.",
    "Brain tumor grading WHO 2021: Grade 1 benign, Grade 2-3 diffuse lower, Grade 4 GBM-equivalent aggressive. IDH critical for prognosis.",
    "T1c MRI: contrast enhancement indicates blood-brain barrier breakdown, microvascular proliferation. Ring-enhancing pattern = GBM hallmark.",
    "FLAIR hyperintensity: vasogenic edema and tumor infiltration beyond contrast-enhancing region. ED volume predicts eloquent cortex involvement.",
    "T2 MRI: hyperintensity = edema, tumor infiltration, necrosis. Whole tumor volume delineation uses T2/FLAIR boundary.",
    "T2-FLAIR mismatch sign: T2 bright tumor with FLAIR hypointense core = IDH-mutant astrocytoma (sensitivity 22%, specificity 100%).",
    "Annular contrast enhancement: highly specific for high-grade glioma GBM grade 4 or brain metastasis. Central necrosis indicates rapid growth.",
    "Restricted diffusion DWI/ADC in tumor core: hypercellularity and high nuclear-to-cytoplasmic ratio correlate with high-grade glioma.",
    "MR spectroscopy in glioma: elevated Cho/NAA ratio (>2), lactate peak, reduced NAA indicate high-grade.",
    "Perfusion MRI DSC: rCBV > 1.75 in contrast-enhancing region correlates with high-grade glioma. rCBV elevation predicts early progression.",
    "Tumor Core TC = NCR + ET: aggressive portion for surgical targeting. ET/TC ratio: >0.6 = highly aggressive enhancing component.",
    "Whole Tumor WT = NCR + ED + ET: total tumor burden for radiotherapy planning. Typical GBM WT: 100-500 cm3.",
    "Enhancing Tumor ET on T1c: correlates with angiogenesis and grade. ET/WT ratio >0.5 indicates diffuse high-grade.",
    "Peritumoral edema ED: FLAIR-T2 hyperintensity beyond TC. Extensive ED (>200 cm3) indicates blood-brain barrier disruption.",
    "NCR/TC ratio >0.3 extensive necrosis: hallmark of GBM grade 4. Necrosis indicates rapid growth outstripping blood supply.",
    "Midline shift >5mm indicates significant mass effect requiring urgent neurosurgical evaluation. Shift >10mm risks transtentorial herniation.",
    "Temporal lobe glioma: involves Wernicke's area dominant, hippocampus memory, Meyer's loop optic radiation. Risk: aphasia, hemianopia.",
    "Frontal lobe glioma: involves prefrontal cortex, Broca's area dominant hemisphere, motor strip. Risk: personality change, motor deficit.",
    "Parietal lobe glioma: involves somatosensory cortex, angular gyrus. Risk: sensory deficits, hemispatial neglect.",
    "Insula glioma: involves language network, autonomic regulation. High surgical risk due to proximity to MCA perforators.",
    "Ventricular involvement and leptomeningeal spread: poor prognostic indicators in GBM. CSF seeding leads to distant CNS metastases.",
    "Stupp protocol 2005: TMZ 75 mg/m2 concurrent RT 60Gy/30fr + 6 cycles adjuvant TMZ 150-200 mg/m2. Standard for GBM MGMT-methylated.",
    "Radiotherapy GBM: 60 Gy in 30 fractions targeting GTV T1c + CTV margin 2cm. IMRT/VMAT techniques for conformality.",
    "Follow-up MRI GBM: every 3 months post-treatment. Pseudoprogression (early T1c increase, FLAIR change) peaks at 12 weeks post-RT.",
    "Molecular testing panel GBM: IDH1/2 sequencing, MGMT methylation pyrosequencing, EGFR FISH, 1p/19q FISH, TERT promoter, CDKN2A FISH.",
    "Bevacizumab Avastin GBM: anti-VEGF antibody reduces edema and radiographic response but no OS benefit newly diagnosed. Used recurrent disease.",
    "Tumor treating fields Optune: 200 kHz alternating electric fields + TMZ. Extends OS in GBM MGMT-methylated (20.9 vs 16.0 months).",
    "GBM prognostic factors: age <50 favorable, KPS >70, GTR vs STR, MGMT methylation, IDH mutation rare in primary GBM.",
    "IDH-wildtype GBM median PFS 6.9 months with TMZ+RT. IDH-mutant grade 4 median OS 4 years. 5-year survival GBM IDH-wildtype <5%.",
    "Diffuse midline glioma H3K27-altered WHO grade 4: thalamus/brainstem/spinal cord. H3K27M mutation by IHC. Median OS 12-18 months."
  ]
}