A comparison of (18)F-dopa PET and inversion recovery MRI in the diagnosis of Parkinson's disease.
OBJECTIVE
To quantify structural changes in the substantia nigra of patients with PD with inversion recovery MRI and to compare these with striatal dopaminergic function measured with (18)F-dopa PET.


METHODS
The authors studied 10 patients with PD and eight age-matched control subjects with a combination of MR sequences previously reported to be sensitive to nigral cell loss. Striatal regions of interest were defined on T1-weighted MRI coregistered to (18)F-dopa PET in all subjects.


RESULTS
Discriminant function analysis of the quantified MR nigral signal correctly classified 83% of the combined PD patient/control group; three of 10 PD cases were incorrectly classified as "normal" (Wilks' lambda = 0.724, p > 0.05). Discriminant function analysis correctly classified 100% of PD patients and control subjects with (18)F-dopa PET based on mean caudate and putamen K(i) values (Wilks' lambda = 0.065, p < 0.001). Correlations between mean putamen K(i) and rostral and caudal nigral MR signal changes and mean caudate K(i) and caudal nigral MR signal changes were found (r = -0.76, -0.69, -0.80, p < 0.05).


CONCLUSIONS
(18)F-dopa PET is more reliable than inversion recovery MRI in discriminating patients with moderately severe PD from normal subjects. However, the structural changes detected within the substantia nigra of patients with PD found using inversion recovery MRI correlate with measures of striatal dopaminergic function using (18)F-dopa PET.
Hu
M T
MT
MRC Cyclotron Building, Medical Research Council Clinical Sciences Centre, and Division of Neuroscience (Drs. Hu and Brooks), and Robert Steiner MR Unit (Drs. Hu, White, Herlihy, and Hajnal), Imperial College School of Medicine, Hammersmith Hospital.
White
S J
SJ
Herlihy
A H
AH
Chaudhuri
K R
KR
Hajnal
J V
JV
Brooks
D J
DJ
D001921:Brain / Q000000981:diagnostic imaging* / Q000473:pathology*; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D010300:Parkinson Disease / Q000000981:diagnostic imaging* / Q000473:pathology*; D014055:Tomography, Emission-Computed
C043437:fluorodopa F 18; D004295:Dihydroxyphenylalanine