title: Weighted registration of 123I-FP-CIT SPECT images improves accuracy of binding potential estimates in pathologically low striatal uptake.
abstract: To test whether the use of a striatum weighted image may improve registration accuracy and diagnostic outcome in patients with parkinsonian syndromes (PS), weighted images were generated by increasing signal intensity of striatal voxels and used as intermediate dataset for co-registering the brain image onto template. Experimental validation was performed using an anthropomorphic striatal phantom. (123)I-FP-CIT SPECT binding ratios were manually determined in 67 PS subjects and compared to those obtained using unsupervised standard (UWR) and weighted registered (WR) approach. Normalized cost function was used to evaluate the accuracy of phantom and subjects registered images to the template. Reproducibility between unsupervised and manual ratios was assessed by using intra-class correlation coefficient (ICC) and Bland and Altman analysis. Correlation coefficient was used to assess the dependence of semi-quantitative ratios on clinical findings. Weighted method improves accuracy of brain registration onto template as determined by cost function in phantom (0.86 ± 0.06 vs. 0.98 ± 0.02; Student's t-test, P = 0.04) and in subject scans (0.69 ± 0.06 vs. 0.53 ± 0.06; Student's t-test, P < 0.0001). Agreement between manual and unsupervised derived binding ratios as measured by ICC was significantly higher on WR as compared to UWR images (0.91 vs. 0.76). Motor UPDRS score was significantly correlated with manual and unsupervised derived binding potential. In phantom, as well as in subjects studies, correlations were more significant using the WR method (BPm: R(2) = 0.36, P = 0.0001; BPwr: R(2) = 0.368, P = 0.0001; BPuwr: R(2) = 0.300, P = 0.0008). Weighted registration improves accuracy of binding potential estimates and may be a promising approach to enhance the diagnostic outcome of SPECT imaging, correlation with disease severity, and for monitoring disease progression in Parkinsonian syndromes.
authors.affiliation: Nuclear Medicine Department, Hospital S. Andrea, La Spezia, Italy. andrea.ciarmiello@asl5.liguria.it
authors.forename: Andrea
authors.initials: A
authors.lastname: Ciarmiello
authors.forename: Giampiero
authors.initials: G
authors.lastname: Giovacchini
authors.forename: Claudio
authors.initials: C
authors.lastname: Guidotti
authors.forename: Martina
authors.initials: M
authors.lastname: Meniconi
authors.forename: Patrizia
authors.initials: P
authors.lastname: Lazzeri
authors.forename: Elena
authors.initials: E
authors.lastname: Carabelli
authors.forename: Luigi
authors.initials: L
authors.lastname: Mansi
authors.forename: Giuliano
authors.initials: G
authors.lastname: Mariani
authors.forename: Duccio
authors.initials: D
authors.lastname: Volterrani
authors.forename: Massimo
authors.initials: M
authors.lastname: Del Sette
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003342:Corpus Striatum / Q000000981:diagnostic imaging* / Q000378:metabolism; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007457:Iodine Radioisotopes / Q000008:administration & dosage / Q000493:pharmacokinetics; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000378:metabolism; D019047:Phantoms, Imaging; D019275:Radiopharmaceuticals / Q000008:administration & dosage / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012189:Retrospective Studies; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014326:Tropanes / Q000008:administration & dosage / Q000493:pharmacokinetics
chemical_list: D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D014326:Tropanes; C087552:2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane