Can a CT head scan be performed on a patient with Parkinson's disease who has a Medtronic (Deep Brain Stimulation) system and has suffered a head injury?

CT Head Scan Safety in Parkinson's Disease Patients with Medtronic DBS System After Head Injury

Yes, a CT head scan can and should be performed immediately in a Parkinson's disease patient with a Medtronic deep brain stimulation (DBS) system who has suffered a head injury. 1

Safety of CT Scanning with DBS Systems

CT scanning is completely safe for patients with implanted DBS systems, unlike MRI which carries significant risks:

• CT scans do not generate the radiofrequency fields that can cause heating of DBS electrodes 2
• CT scanning is the preferred initial imaging modality for all head trauma patients, including those with implanted neurostimulation devices 3, 1
• The American College of Radiology guidelines support CT as the first-line imaging for head trauma evaluation 3

Clinical Decision-Making for Head Trauma in DBS Patients

Indications for Immediate CT Head Scan

• Any head injury in a patient with DBS requires immediate CT evaluation due to:
  • Risk of intracranial hemorrhage that could be life-threatening
  • Potential displacement or damage to the DBS electrodes
  • Need to rule out skull fractures that might affect the DBS system 3

Risk Assessment

• Patients with Parkinson's disease have:
  • Increased fall risk due to gait and balance impairments 4
  • Higher risk of traumatic brain injury complications due to age and comorbidities
  • Potential for post-traumatic exacerbation of Parkinsonian symptoms 5

Imaging Protocol Considerations

CT Head Protocol

• Non-contrast CT is the appropriate initial study 1
• The scan should include:
  • Complete visualization of the brain parenchyma
  • Evaluation of the skull for fractures
  • Assessment of DBS electrode positioning 3

Artifact Considerations

• DBS electrodes will create some artifact on CT images
• Despite artifacts, CT remains highly sensitive for detecting:
  • Acute hemorrhage
  • Mass effect
  • Midline shift
  • Skull fractures 3

Post-Imaging Management

If CT Shows Abnormalities

• Immediate neurosurgical consultation is required for:
  • Any intracranial hemorrhage
  • Electrode displacement
  • Skull fractures near the DBS hardware 3

If Initial CT is Negative

• Consider follow-up CT in 12-24 hours if:
  • Patient is on anticoagulants
  • Neurological status changes
  • Persistent severe headache or vomiting 3

Important Cautions and Pitfalls

MRI Contraindication

• Never substitute MRI for CT in emergency evaluation of DBS patients with head trauma
• MRI can cause permanent neurological injury due to heating of DBS electrodes 2
• Even "MRI-conditional" DBS systems require specific protocols that are impractical in emergency settings

DBS System Evaluation

• After head trauma, the DBS system should be evaluated by a movement disorders specialist or neurosurgeon familiar with the device
• The system may need reprogramming if the patient experiences changes in symptom control 4, 6

Conclusion

In a patient with Parkinson's disease using a Medtronic DBS system who has suffered a head injury, immediate CT head scanning is both safe and necessary to evaluate for potential intracranial injuries. CT scanning poses no risk to the DBS hardware and provides crucial information for clinical management.