Copyright 2002 American Medical Association. All Rights Reserved. Applicable FARS/DFARS Restrictions Apply to Government Use.
We thank Fernandez and Friedman for their comments. Although the results they mention were obtained in a small number of subjects, they point out an unresolved question: whether patients with PD can have normal findings on 18F-dopa PET scans. From our results, one could extrapolate that the compensatory increase of the dopa decarboxylase might produce normal 18F-dopa PET scan findings despite the disappearance of 20% or 30% of the dopaminergic neurons. However, the study showing that 18F-dopa uptake is highly correlated to motor function suggests that when this uptake is normal, the motor performance is nearly normal. Finally, abnormal results on 18F-dopa PET scans have occurred in asymptomatic co-twins of patients with PD.1 Although this type of PD is probably genetic and may be different from the idiopathic form, this finding argues against the likelihood of PD symptoms without abnormal 18F-dopa PET scan findings. Finally, technical parameters for image acquisition and analysis might influence the ability to discriminate between normal and abnormal results on these scans. Consequently, reporting and following cases of PD that demonstrate normal findings on 18F-dopa PET scans and abnormal results on examinations using DAT ligands is of major interest.
Some of us were investigators for the REAL-PET Study,2 which measured the progression of Parkinson disease for 2 years using 18F-dopa in patients blindly assigned to treatment with ropinirole hydrochloride or levodopa. We cannot comment on this study because the data are still unpublished. However, the subjects with normal 18F-dopa PET scan findings at baseline who were excluded from the analysis also had normal PET scan results after 2 years of follow-up, which is very unlikely in patients with PD. Moreover, the caudate-putamen ratio in these subjects was abnormally high considering the usual pattern of dopaminergic denervation in PD.3 - 4 Unfortunately, it is possible that the PET scan analysis revealed misdiagnosis in these subjects. However, we recommend that our colleagues refer directly to the published data when available.
Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature
Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal
Instructions
Comments are moderated and will appear on the site at the discretion of the Archives of Neurology editors. Comments should not exceed 500 words of text and 10 references.
Do not submit personal medical questions or information that could identify a specific patient, questions about a particular case, or general inquiries to an author. Only content that has not been published, posted, or submitted elsewhere should be submitted. By submitting this Comment, you and any coauthors transfer copyright to the journal if your Comment is posted.
* = Required Field
Disclosure of Any Conflicts of Interest* Indicate all relevant conflicts of interest of each author below, including all relevant financial interests, activities, and relationships within the past 3 years including, but not limited to, employment, affiliation, grants or funding, consultancies, honoraria or payment, speakers’ bureaus, stock ownership or options, expert testimony, royalties, donation of medical equipment, or patents planned, pending, or issued. If all authors have none, check "No potential conflicts or relevant financial interests" in the box below. Please also indicate any funding received in support of this work. The information will be posted with your response.
Register and get free email Table of Contents alerts, saved searches, PowerPoint downloads, CME quizzes, and more
Subscribe for full-text access to content from 1998 forward and a host of useful features
Activate your current subscription (AMA members and current subscribers)
Some tools below are only available to our subscribers or users with an online account.
Download citation file:
Customize your page view by dragging & repositioning the boxes below.
and access these and other features:
Register Now
Enter your username and email address. We'll send you a reminder to the email address on record.
Athens and Shibboleth are access management services that provide single sign-on to protected resources. They replace the multiple user names and passwords necessary to access subscription-based content with a single user name and password that can be entered once per session. It operates independently of a user's location or IP address. If your institution uses Athens or Shibboleth authentication, please contact your site administrator to receive your user name and password.