Evaluation of Striatal Dopamine Transporter Function in Rats by in Vivo β-[123I]CIT Pinhole SPECT

Morphologic and functional changes in the unilateral 6-hydroxydopamine lesion rat model for Parkinson’s disease discerned with μSPECT and quantitative MRI

“…As a biological analog of dopamine and noradrenaline, 6OHDA is transported into catecholaminergic neurons, where it is metabolized, causing cytotoxicity and subsequent neuronal cell death [15]. The validity of this animal model has been demonstrated by invasive histological and electrophysiological analysis [15] and by in vivo imaging techniques such as microSPECT (single photon emission computed tomography) consistently demonstrating large decreases in DATbinding capacity in the affected striatum [16][17][18][19].…”

SPECT Low-Field MRI System for Small-Animal Imaging

“…Current MRI strategies for small animals are more frequently based on 2-dimensional (2D) multislice acquisition instead of time-consuming isotropic volume imaging sequences. In-plane pixel resolution ranging from 0.15 to 0.25 mm and slice thickness ranging from 0.7 to 2 mm were obtained using clinical scanners at 1.5 T for separate SPECT and MRI rat brain studies (4,5,7). Also, for comparison, a 0.8 · 0.8 · 0.8 mm 3 voxel has been used for a whole-body mouse MR acquisition in separate PET and MRI studies using a 4.7-T magnetic field (24).…”

“…Imaging cell and animal (3) are translated along the imaging axis (2) from the MRI device to a single-detector pinhole SPECT device (1). Illustration shows orientation of the vertical B 0 main magnetic field of the MR magnet and corresponding power supply (4). (B) Close-up view of the nonmagnetic imaging cell: solenoidal whole-body RF transmit-and-receive coil (1); pickup coil (2) outside the isolating heated polymethyl methacrylate chamber (3); anesthetic gases are delivered to animal through a dedicated mask (4).…”

“…Yet, compared with CT, the use of MRI for coregistration of both functional and structural information has, to our knowledge, essentially served to demonstrate the potential interest of using coregistration of images after data acquisition in separate nuclear and MR rooms. However, as experienced for rat and mice, the strategy of pinhole SPECT followed by MRI in a clinical scanner is a long and complicated task (4-7), requiring a careful transfer of the animal in a specially designed bed equipped with multimodality fiducial markers helping in the coregistration of images (4,5). In addition, separate dual-modality scans (followed by image fusion) are also potential sources of misalignment of images due to uncontrolled movements and displacements of tissues and organs.…”

In vivo snapshots of the dopaminergic synapse in small animals

“…Thereby, most investigators focus on rat models of neurodegenerative diseases such as Parkinson's and Huntington's disease, and assess either DAT or D 2 R binding in lesioned and control animals with either dedicated small animal PET (for a review see Nikolaus et al 9 ) or conventional clinical SPECT cameras equipped with highly resolving single-pinhole collimators. [10][11][12] In one study, both pre-and postsynaptic binding were assessed in the same animals showing a decrease of DAT together with an increase of D 2 R binding contingent on 6-hydroxydopamine-lesion of the nigrostriatal pathway. 13 So far, however, no in vivo investigations have been performed in rats on the relation between synaptic dopamine and pre-/postsynaptic radioligand binding in quantitative terms.…”