Ketamine and fMRI for Neuropathic Pain
Condition: Neuralgia
MeSH terms: Neuralgia
Study type: Interventional

Summary: 
      Neuropathic or nerve injury related pain (NP), an extremely unpleasant condition that is
      difficult to treat, often has a severe, persistent, and unremitting course. Conventional
      treatments are often ineffective in relieving NP. Recently, the investigators have developed
      a cost-efficient regimen involving use of low dose infusions of ketamine for treating
      neuropathic pain in patients in whom oral medications have failed. We have observed excellent
      benefits in many of these patients. However, this treatment requires titration and monitoring
      during the infusion and currently it is not possible to predict which patients will benefit
      from this intervention. The investigators have shown that functional magnetic resonance
      imaging (fMRI) of the brain can be used as a tool to predict relief of pain and to assess the
      effect of treatment in some chronic pain conditions. This innovative project involves
      development of an fMRI-guided treatment with intravenous ketamine in patients with NP. This
      study aims to analyze patterns of changes in fMRI of the brain, before and after infusion of
      ketamine and to correlate the changes with pain intensity. The information from this study
      will help to deliver this therapy earlier to those patients who are most likely to benefit
      from ketamine.
    

Detailed description: 
      This trial is exploratory, prospective, non-randomized, single cohort, single-center, with no
      blinding of participants, treating physicians, and investigators. Study participants undergo
      a resting-state fMRI before, after and at '1-month post-ketamine infusion' (standard care).
      Patients will be recruited over 2 years, from Pain Clinics at Toronto Western Hospital and
      Mount Sinai Hospital. The primary null hypothesis for this trial is that there are no fMRI
      brain patterns of patients with neuropathic pain that predict pain relief following ketamine
      infusion. The secondary null hypothesis for this trial is that there are no correlations
      between specific fMRI brain patterns of patients with neuropathic pain and change in
      intensity of pain immediately following ketamine infusion. Further secondary hypothesis
      include that cortical reorganization in the brain as measured by fMRI at one month after the
      infusion of ketamine does not correlate with persisting analgesic benefit in patients with
      neuropathic pain. Finally, we hypothesize that ketamine infusions do not provide significant
      pain relief, reduction in anxiety and depression, and improvement in quality of life early
      (at 1 month) and late (at 3 months) after the infusions in patients with neuropathic pain.
    

Intervention name(s): RS-fMRI; Ketamine
Intervention type(s): Other; Drug
Intervention description(s): Resting State-functional Magnetic Resonance Imaging. Protocols involving BOLD (blood oxygen level-dependent) and non-BOLD techniques will be used.; Part of standard care. To be performed over five consecutive days (Monday to Friday) for six hours per day. A therapeutic range of 0.5 to 2.0 mg/kg/hour is targeted.
Intervention MeSH terms: Ketamine
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Diagnostic
Keywords: Ketamine; fMRI; refractory neuropathic pain