Brain & Neurology PET
Brain PET Cases
Organized by clinical question across all brain PET tracers — amyloid, tau, FET, FDOPA, and FDG. Cases added regularly.
A/T/N FrameworkAmyloid & TauFET / FDOPAPET/MRIPseudoprogressionBraak StagingAnti-Amyloid Therapy
Alzheimer's disease is defined by biology, not symptoms. The A/T/N biomarker framework — Amyloid, Tau, Neurodegeneration — is now the basis for diagnosis, prognosis, and clinical trial eligibility.
Cases Coming Soon
Amyloid PET — MCI Workup
Positive vs negative visual readGrey-white contrast lossPosterior cingulate & precuneusA/T/N frameworkCentiloid scaleAnti-amyloid therapy eligibility
Cases Coming Soon
Tau PET — Braak Staging
Braak I–II: entorhinal/MTLBraak III–IV: inferior temporalBraak V–VI: neocortical spreadClinical severity correlationFlortaucipir vs MK-6240
Cases Coming Soon
Amyloid + Tau Companion Cases
A+T+ — Alzheimer'sA+T- — preclinical ADA-T+ — primary tauopathyTreatment selection implications
Cases Coming Soon
Negative Amyloid PET
Normal agingNon-AD dementiaFTD patterns on FDGDLB — FDG & DaT-SPECT
⚠️ Pitfalls & Normal Variants — Cases Coming Soon
Dementia Imaging Pitfalls
Choroid plexus spill — tau pitfallWhite matter striations — amyloid false positiveAge-related amyloid accumulationCerebrovascular disease confoundsOff-target flortaucipir binding
Amino acid PET tracers (FET, FDOPA) distinguish tumor from treatment effect where MRI is equivocal. A critical clinical application where PET changes management in ~40% of cases.
Cases Coming Soon
FET PET — Glioma Recurrence vs Radiation Necrosis
TBRmax thresholdsLate frame imaging 20–40 minDynamic kineticsRing uptake patternRANO-NM criteria
Cases Coming Soon
FDOPA PET — Neuro-oncology
Glioma characterizationStriatum as referenceTBR calculationComparison with FET
Cases Coming Soon
Pseudoprogression
Post-Stupp protocolEnhancing lesion on MRIEarly post-RT timingPET resolves ambiguityManagement impact
Cases Coming Soon
Treatment Planning & Biopsy Guidance
Hotspot targetingHeterogeneous tumorsRadiation boost planningRecurrence mapping
⚠️ Pitfalls & Normal Variants — Cases Coming Soon
Neuro-oncology Pitfalls
Radiation necrosis can show elevated TBRDynamic kinetics needed for full pictureCortical gray matter — high physiologic FDOPAStriatal uptake — always show in frameLow-grade glioma — FDG often normal
FDOPA PET characterizes presynaptic dopaminergic terminal loss, distinguishing Parkinson disease from atypical parkinsonism and essential tremor.
Cases Coming Soon
Parkinson Disease vs MSA
Putamen-to-caudate ratioPosterior putamen loss first in PDSymmetric vs asymmetricMSA — more symmetric loss
Cases Coming Soon
Parkinson vs Essential Tremor
Normal FDOPA in ETReduced putamen in PDClinical impactDaT-SPECT comparison
Cases Coming Soon
DLB — FDOPA & FDG
Occipital hypometabolism on FDGReduced striatal FDOPACingulate island signDaT-SPECT complement
⚠️ Pitfalls & Normal Variants — Cases Coming Soon
Movement Disorder Pitfalls
Normal aging — mild putamen reductionDrug-induced parkinsonism — normal FDOPAAsymmetric tremor — unilateral reductionVascular parkinsonism patterns
Brain SPECT cases (perfusion SPECT for dementia, seizure localization, brain death) are organized in the General Nuclear Medicine wing.
Cases Coming Soon
Tc-99m HMPAO/ECD Perfusion SPECT
Alzheimer's — posterior patternFTD — frontal patternSeizure lateralizationBrain death confirmation
Cases Coming Soon
DaT-SPECT (¹²³I-Ioflupane)
Striatal uptake ratioPD vs ETAtypical parkinsonismComma vs period sign
⚠️ Pitfalls & Normal Variants — Cases Coming Soon
Brain SPECT Pitfalls
Patient motion artifactAttenuation — posterior fossaMedication effects on DaTNormal variant asymmetry
Key References & Resources