II. Epidemiology

  1. Incidence: Neuroimaging in first non-febrile Seizure Evaluation identifies a structural Brain Lesion
    1. Adults: 33%
    2. Infants <6 months: 50%

III. Techniques: Imaging Studies after first Seizure

  1. Step 1: Urgent CT Head (acute to exclude Hemorrhage)
    1. Indicated urgently for at risk patients to exclude conditions that change acute management
      1. Found in 17% of adults and 8% of children
    2. Patient without risk factors for intracranial pathology
      1. May wait for outpatient imaging typically with MRI Brain
    3. Contrast needed only in HIV or cancer history where tumor or abscess is suspected
  2. Step 2: Routine MRI Head (preferred for structural exam)
    1. Higher efficacy than Head CT in identifying underlying Brain Lesions
    2. No radiation exposure (see Cancer Risk due to Diagnostic Radiology)
      1. Even a greater concern in children in whom radiation exposure carries higher lifetime cancer risk

IV. Indications: Adults

  1. All adults should have Neuroimaging after First Seizure (per ACEP and AAN)
    1. Timing of neuroimaging depends on presentation
    2. At risk patients, should undergo urgent Head CT, followed by later MRI Brain
    3. Stable patients may wait to undergo outpatient MRI Brain (if no contraindication for delay)
  2. Urgent neuroimaging indications (typically CT Head)
    1. Acute Head Trauma
    2. Age over 40 years
    3. AIDS
    4. Altered Mental Status persists
    5. Anticoagulation
    6. Fever
    7. Focal neurologic deficit of new onset
    8. Headache persists
    9. Malignancy
    10. Partial Seizure (focal Seizure)
  3. Deferred outpatient neuroimaging indications (typically MRI Head)
    1. Stable patient and
    2. No urgent neuroimaging indications (see above) and
    3. Reliable patient for follow-up and
    4. Returned to baseline mental status during emergency department evaluation

V. Indications: Children

  1. All patients under age 1 year
  2. Cognitive or Motor Developmental Delay
  3. EEG with primary generalized Epilepsy
  4. Head Trauma
  5. Malignancy
  6. Brain Tumor
  7. Prior Cerebrovascular Accident
  8. Coagulopathy
  9. Sickle Cell Disease
  10. Prior CNS surgery with shunt
  11. Mental status changes persist
  12. Partial Seizure (focal Seizure)
  13. Postictal neurologic deficit that persists

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