Usefulness of F-18 FP-CIT PET to predict dopamine-responsive hand tremor in patients other than Parkinson's disease: Two case reports

RATIONALE: Treating the patients with hand tremors is clinically difficult, because a wide range of disorders can result in hand tremors. Therefore, when treatment for hand tremors begins, various pharmacological options have to be considered. In clinical practice, a practical approach is to initially check hand tremor patients for signs of Parkinson's disease (PD), because patients with PD can benefit from dopamine treatment. However, only part of patients with PD tends to show a meaningful improvement in hand tremors for dopamine treatment. On the other hand, dopamine treatment may help with hand tremors of patients with other disorders, but dopamine responsiveness can‘t be predicted by clinical assessment alone. PATIENTS CONCERNS: Hand tremors. DIAGNOSES: Hemiplegic patients (A 78-year-old man with cerebral infarction and a 65-year-old woman with traumatic brain injury) with hemi-sided hand tremor. INTERVENTIONS: Fluorinated N-3-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl) nortropane (F-18 FP-CIT) positron emission tomography (PET) and dopamine agonist. OUTCOMES: After the medication, hemi-side hand tremor dramatically improved. LESSONS: Collectively, a dysfunction of the dopaminergic nigro-striatal pathway may lead to abnormal findings of F-18 FP-CIT PET, and these abnormal findings in brain-lesion patients with hand tremor may help predict dopamine responsiveness of hand tremor. We believe that our report may be helpful in the diagnosis and treatment of hand tremor in patients with brain-lesion.