Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

Ziel/Aim:

Moyamoya disease (MMD) is characterized by progressive stenosis or occlusion of the terminal internal carotid arteries with varying development of collaterals requiring the exact characterization of hemodynamics for adequate therapy. The aim of the present study was to compare perfusion SPECT and PET with O-15-water in the same patients.

Methodik/Methods:

Static SPECT and dynamic PET were performed within 1-5 d in 9 MMD patients (18-67 y), both in resting state and after vasodilatory challenge with acetazolamide. The PET data were analyzed with the Watabe reference tissue method for the voxelwise computation of the regional cerebral blood flow. Vasodilatation and resting images were coregistered, stereotactically normalized (SPM8) and smoothed (3d isotropic Gaussian kernel, 20 mm FWHM). The relative cerebrovascular reserve (rCVR) was computed voxel-by-voxel according to the formula rCVR = 100*(s*vasodilatation – resting)/resting. The scale factor (s) was determined to a mean rCVR of 50%. The resulting rCVR maps were assessed visually and using standard ROIS for ACA, MCA and PCA territory (left/ right). A general linear model was used to analyze the effect of modality (SPECT, PET) and territory (ACA, MCA, PCA) on rCVR.

Ergebnisse/Results:

The pattern of rCVR differed significantly between SPECT and PET in 5/9 patients according to visual inspection. PET showed additional or more extended regions with reduced rCVR in these cases. The ROI analysis revealed a significant effect of the modality (p=0.015) and a highly significant modality*territory interaction (p=0.000). PET-rCVR was lower than SPECT-rCVR in the ACA and MCA territory, whereas it was higher in the PCA territory.

Schlussfolgerungen/Conclusions:

There was a substantial difference in the cerebrovascular reserve capacity as measured by SPECT versus PET, both visually and quantitatively. The modality*territory interaction suggests that PET is more accurate than SPECT, as MMD often spares the posterior circulation. However, this has to be confirmed in further studies.