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Imaging Experimental Brain Tumors with 1-Aminocyclopentane Carboxylic Acid and Alpha-Aminoisobutyric Acid: Comparison to Fluorodeoxyglucose and Diethylenetriaminepentaacetic Acid in Morphologically Defined Tumor Regions
- Source :
- Journal of Cerebral Blood Flow & Metabolism. 17:1239-1253
- Publication Year :
- 1997
- Publisher :
- SAGE Publications, 1997.
-
Abstract
- The goal of this study was to evaluate the differences and define the advantages of imaging experimental brain tumors in rats with two nonmetabolized amino acids, 1-aminocyclopentane carboxylic (ACPC) acid and α-aminoisobutyric (AIB) acid compared with imaging with fluorodeoxyglucose (FDG) or the gallium-diethylenetriaminepentaacetic acid chelate (Ga-DTPA). 1-aminocyclopentane carboxylic acid, AIB, and FDG autoradiograms were obtained 60 minutes after intravenous injection to simulate positron emission tomography (PET) imaging, whereas the Ga-DTPA autoradiograms were obtained 5 or 10 minutes after injection to simulate gadolinium (Gd)-DTPA–enhanced magnetic resonance (MR) images. Three experimental tumors were studied (C6, RG2, and Walker 256) to provide a range of tumor types. Triple-label quantitative autoradiography was performed, and parametric images of the apparent distribution volume (Va, mL/g) for ACPC or AIB, relative glucose metabolism (R, μmol/100 g/min), vascular permeability to Ga-DTPA (K1, μL/min/g), and histology were obtained from the same tissue section. The four images were registered in an image array processor, and regions of interest in tumor and contralateral brain were defined on morphologic criteria (histology) and were transferred to the autoradiographic images. A comparative analysis of all measured values was performed. The location and morphologic characteristics of the tumor had an effect on the images and measurements of Va, R, and K1. Meningeal extensions of all three tumors consistently had the highest amino acid uptake (Va) and vascular permeability (K1) values, and subcortical portions of the tumors usually had the lowest values. Va and R (FDG) values generally were higher in tumor regions with high-cell density and lower in regions with low-cell density. Tumor areas identified as “impending” necrosis on morphologic criteria consistently had high R values, but little or no change in Va or K1. Tumor necrosis was seen consistently only in the larger Walker 256 tumors; low values of R and Va for AIB (less for ACPC) were measured in the necrotic-appearing regions, whereas K1 was not different from the mean tumor value. The highest correlations were observed between vascular permeability (K1 for Ga-DTPA) and Va for AIB in all three tumors; little or no correlation between vascular permeability and R was observed. The advantages of ACPC and AIB imaging were most convincingly demonstrated in C6 gliomas and in Walker 256 tumors. 1-aminocyclopentane was substantially better than FDG or Ga-DTPA for identifying tumor infiltration of adjacent brain tissue beyond the macroscopic border of the tumor; ACPC also may be useful for identifying low-grade tumors with an intact blood–brain barrier. Contrast-enhancing regions of the tumors were visualized more clearly with AIB than with FDG or Ga-DTPA; viable and necrotic-appearing tumor regions could be distinguished more readily with AIB than with FDG. [11C]-labeled ACPC and AIB are likely to have similar advantages for imaging human brain tumors with PET.
- Subjects :
- Male
Pathology
medicine.medical_specialty
Aminoisobutyric Acids
Time Factors
Gadolinium
Rats, Inbred WF
chemistry.chemical_element
Vascular permeability
030218 nuclear medicine & medical imaging
Rats, Sprague-Dawley
03 medical and health sciences
0302 clinical medicine
Fluorodeoxyglucose F18
Tumor Cells, Cultured
medicine
Animals
Humans
Cycloleucine
Fluorodeoxyglucose
chemistry.chemical_classification
medicine.diagnostic_test
Brain Neoplasms
Chemistry
business.industry
Histology
Magnetic resonance imaging
Human brain
Pentetic Acid
Rats, Inbred F344
Rats
Amino acid
medicine.anatomical_structure
Neurology
Positron emission tomography
Autoradiography
Neurology (clinical)
Radiopharmaceuticals
Cardiology and Cardiovascular Medicine
Nuclear medicine
business
Neoplasm Transplantation
030217 neurology & neurosurgery
medicine.drug
Subjects
Details
- ISSN :
- 15597016 and 0271678X
- Volume :
- 17
- Database :
- OpenAIRE
- Journal :
- Journal of Cerebral Blood Flow & Metabolism
- Accession number :
- edsair.doi.dedup.....661ccdd42c339f39a70e089e6598e5b5