TY - CHAP A1 - Pietrzyk, Uwe A1 - Bauer, Dagmar A1 - Vieten, Andrea A1 - Bauer, Andreas A1 - Langen, Karl-Josef A1 - Zilles, Karl A1 - Palm, Christoph T1 - Creating consistent 3D multi-modality data sets from autoradiographic and histological images of the rat brain T2 - IEEE Nuclear Science Symposium Conference Record N2 - Volumetric representations of autoradiographic and histological images gain ever more interest as a base to interpret data obtained with /spl mu/-imaging devices like microPET. Beyond supporting spatial orientation within rat brains especially autoradiographic images may serve as a base to quantitatively evaluate the complex uptake patterns of microPET studies with receptor ligands or tumor tracers. They may also serve for the development of rat brain atlases or data models, which can be explored during further image analysis or simulation studies. In all cases a consistent spatial representation of the rat brain, i.e. its anatomy and the corresponding quantitative uptake pattern, is required. This includes both, a restacking of the individual two-dimensional images and the exact registration of the respective volumes. We propose strategies how these volumes can be created in a consistent way and trying to limit the requirements on the circumstances during data acquisition, i.e. being independent from other sources like video imaging of the block face prior to cutting or high resolution micro-X-ray CT or micro MRI. KW - Neoplasms KW - Data models KW - Image analysis KW - Brain modeling KW - Analytical models KW - Anatomy KW - Data acquisition KW - High-resolution imaging KW - Image resolution KW - Computed tomography Y1 - 2004 U6 - https://doi.org/10.1109/NSSMIC.2004.1466754 VL - 6 SP - 4001 EP - 4003 ER - TY - CHAP A1 - Palm, Christoph A1 - Vieten, Andrea A1 - Bauer, Dagmar A1 - Pietrzyk, Uwe T1 - Evaluierung von Registrierungsstrategien zur multimodalen 3D-Rekonstruktion von Rattenhirnschnitten T2 - Bildverarbeitung für die Medizin 2006 N2 - In dieser Arbeit werden drei Strategien zur 3D Stapelung von multimodalen Schnittbildern vorgestellt. Die Strategien werden experimentell anhand von Dualtracer-Autoradiographien evaluiert. Dazu werden neue Maße zur Beschreibung der Konsistenz innerhalb einer Modalität und der Konsistenz der Modalitäten untereinander entwickelt, die auf bekannten Registrierungsmetriken basieren. Gerade bezüglich der Konsistenz der Modalitäten untereinander zeigen zwei Strategien die besten Resultate: (1) abwechselnde multimodale Registrierung (2) monomodale Rekonstruktion einer Modalität und multimodale 2D Registrierung der zweiten Modalität. KW - Registrierung KW - Dreidimensionale Rekonstruktion KW - Gehirn KW - Schnittpräparat Y1 - 2006 U6 - https://doi.org/10.1007/3-540-32137-3_51 SP - 251 EP - 255 PB - Springer CY - Berlin ER - TY - JOUR A1 - Bauer, Dagmar A1 - Hamacher, Kurt A1 - Bröer, Stefan A1 - Pauleit, Dirk A1 - Palm, Christoph A1 - Zilles, Karl A1 - Coenen, Heinz H. A1 - Langen, Karl-Josef T1 - Preferred stereoselective brain uptake of D-serine BT - a modulator of glutamatergic neurotransmission JF - Nuclear Medicine and Biology N2 - Although it has long been presumed that d-amino acids are uncommon in mammalians, substantial amounts of free d-serine have been detected in the mammalian brain. d-Serine has been demonstrated to be an important modulator of glutamatergic neurotransmission and acts as an agonist at the strychnine-insensitive glycine site of N-methyl-d-aspartate receptors. The blood-to-brain transfer of d-serine is thought to be extremely low, and it is assumed that d-serine is generated by isomerization of l-serine in the brain. Stimulated by the observation of a preferred transport of the d-isomer of proline at the blood–brain barrier, we investigated the differential uptake of [3H]-d-serine and [3H]-l-serine in the rat brain 1 h after intravenous injection using quantitative autoradiography. Surprisingly, brain uptake of [3H]-d-serine was significantly higher than that of [3H]-l-serine, indicating a preferred transport of the d-enantiomer of serine at the blood–brain barrier. This finding indicates that exogenous d-serine may have a direct influence on glutamatergic neurotransmission and associated diseases. KW - Aminosäuren KW - Gehirn KW - Blut-Hirn-Schranke KW - Aufnahme KW - d/l-serine KW - Amino acid transport KW - Blood–brain barrier KW - NMDA receptors Y1 - 2005 U6 - https://doi.org/10.1016/j.nucmedbio.2005.07.004 VL - 32 IS - 8 SP - 793 EP - 797 ER - TY - GEN A1 - Bauer, Dagmar A1 - Stoffels, Gabriele A1 - Pauleit, Dirk A1 - Palm, Christoph A1 - Hamacher, Kurt A1 - Coenen, Heinz H. A1 - Langen, Karl T1 - Uptake of F-18-fluoroethyl-L-tyrosine and H-3-L-methionine in focal cortical ischemia T2 - The Journal of Nuclear Medicine N2 - Objectives: C-11-methionine (MET) is particularly useful in brain tumor diagnosis but unspecific uptake e.g. in cerebral ischemia has been reported (1). The F-18-labeled amino acid O-(2-[F-18]fluoroethyl)-L-tyrosine (FET) shows a similar clinical potential as MET in brain tumor diagnosis but is applicable on a wider clinical scale. The aim of this study was to evaluate the uptake of FET and H-3-MET in focal cortical ischemia in rats by dual tracer autoradiography. Methods: Focal cortical ischemia was induced in 12 Fisher CDF rats using the photothrombosis model (PT). One day (n=3) , two days (n=5) and 7 days (n=4) after induction of the lesion FET and H-3-MET were injected intravenously. One hour after tracer injection animals were killed, the brains were removed immediately and frozen in 2-methylbutane at -50°C. Brains were cut in coronal sections (thickness: 20 µm) and exposed first to H-3 insensitive photoimager plates to measure FET distribution. After decay of F-18 the distribution of H-3-MET was determined. The autoradiograms were evaluated by regions of interest (ROIs) placed on areas with increased tracer uptake in the PT and the contralateral brain. Lesion to brain ratios (L/B) were calculated by dividing the mean uptake in the lesion and the brain. Based on previous studies in gliomas a L/B ratio > 1.6 was considered as pathological for FET. Results: Variable increased uptake of both tracers was observed in the PT and its demarcation zone at all stages after PT. The cut-off level of 1.6 for FET was exceeded in 9/12 animals. One day after PT the L/B ratios were 2.0 ± 0.6 for FET vs. 2.1 ± 1.0 for MET (mean ± SD); two days after lesion 2.2 ± 0.7 for FET vs. 2.7 ± 1.0 for MET and 7 days after lesion 2.4 ± 0.4 for FET vs. 2.4 ± 0.1 for MET. In single cases discrepancies in the uptake pattern of FET and MET were observed. Conclusions: FET like MET may exhibit significant uptake in infarcted areas or the immediate vincinity which has to be considered in the differential diagnosis of unkown brain lesions. The discrepancies in the uptake pattern of FET and MET in some cases indicates either differences in the transport mechanisms of both amino acids or a different affinity for certain cellular components. Y1 - 2006 UR - http://jnm.snmjournals.org/content/47/suppl_1/284P.3 VL - 47 IS - Suppl. 1 SP - 284P ER -