TY  - JOUR
A1  - Brumberg, Joachim
A1  - Blazhenets, Ganna
A1  - Schröter, Nils
A1  - Frings, Lars
A1  - Jost, Wolfgang H.
A1  - Lapa, Constantin
A1  - Meyer, Philipp T.
T1  - Imaging cardiac sympathetic innervation with MIBG: linear conversion of the heart-to-mediastinum ratio between different collimators
JF  - EJNMMI Physics
N2  - Background
The heart-to-mediastinum (H/M) ratio is a commonly used parameter to measure cardiac I-123 metaiodobenzylguanidine (MIBG) uptake. Since the H/M ratio is substantially influenced by the collimator type, we investigated whether an empirical linear conversion of H/M ratios between camera systems with low-energy (LE) and medium-energy (ME) collimator is possible.

Methods
We included 18 patients with parkinsonism who were referred to one of the two participating molecular imaging facilities for the evaluation of cardiac sympathetic innervation by MIBG scintigraphy. Two consecutive planar image datasets were acquired with LE and ME collimators at 4 h after MIBG administration. Linear regression analyses were performed to describe the association between the H/M ratios gained with both collimator settings, and the accuracy of a linear transfer of the H/M ratio between collimators and across centers was assessed using a leave-one-out procedure.

Results
H/M ratios acquired with LE and ME collimators showed a strong linear relationship both within each imaging facility (R\(^2\) = 0.99, p < 0.001 and R\(^2\) = 0.90, p < 0.001) and across centers (H/M-LE = 0.41 × H/M-ME + 0.63, R\(^2\) = 0.97, p < 0.001). A linear conversion of H/M ratios between collimators and across centers was estimated to be very accurate (mean absolute error 0.05 ± 0.04; mean relative absolute error 3.2 ± 2.6%).

Conclusions
The present study demonstrates that a simple linear conversion of H/M ratios acquired with different collimators is possible with high accuracy. This should greatly facilitate the exchange of normative data between settings and pooling of data from different institutions.
KW  - MIBG
KW  - collimator
KW  - heart-to-mediastinum ratio
KW  - linear conversion
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-221675
VL  - 6
ER  -