NMR imaging and spectroscopy of the mammalian central nervous system after heavy ion radiation

Richards, T

doi:10.2172/6268623

Cited by 3 publications

(5 citation statements)

References 21 publications

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“…The gadolinium enhancement at 4 months was interesting in light of our previous work [15] and previous work by Richards and Buddinger [13] , Remler et al [16] , Karger et al [17] , Altschuler et al [18] , and Mori et al [19] . Here, we showed that at the 90 CGE level there is disruption of normal brain architecture with heterogeneous enhancement.…”

Section: Discussionmentioning

confidence: 61%

“…At 4 weeks a time point when there should be tissue injury evident by T2 weighted images and gadolinium enhancement, no changes were detected on the 4.7 T in vivo MRI examination. The study from Richards and Buddinger [13] demonstrated some changes using a 4.3 T in vivo MR spectroscopic examination. In the five animals tested at 30 Gy, they found increase in lactate relative to NAA in the treated hemisphere 11.5 weeks following irradiation.…”

Section: Discussionmentioning

confidence: 99%

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MR Spectroscopic Changes in the Rat Hippocampus following Proton Radiosurgery

Rabinov¹,

Cheng

Lee

et al. 2006

Stereotact Funct Neurosurg

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Purpose: To identify MR spectroscopic changes in the rat hippocampus following proton radiosurgery. Methods and Materials: A group of 12 rats were treated with Bragg peak proton beam irradiation involving the right hippocampus. Single doses of 30 CGE, 50 CGE, 70 CGE, 90 CGE were delivered to groups of 3 animals using single fraction technique. Animals were imaged using a standard 3 T GE Signa MRI at 4 months following treatment. An untreated animal was also studied. A 3″ surface coil was employed to obtain T1 weighted coronal pre- and post-gadolinium images (TR 600 and TE 30) and dual echo T2 weighted coronal images (TR 3000, TE 30/90). Volumetric analysis with custom software was done to evaluate areas of increased signal on T2 weighted images and the development of hydrocephalus was examined. Animals were sacrificed and specimens of the treated hippocampus were harvested for High Resolution Magic Angle Spinning MR Spectroscopy (HRMAS) followed by histopathology of the tissue samples. Peak values of choline, creatine, N-acetyl aspartate and lipids were evaluated and compared. Results: Peak tissue injury occurred in the surviving 90 CGE animal by both T2 weighted and post-gadolinium imaging. Gadolinium enhancement was seen in decreasing volumes of tissue at dosage levels from 90 to 50 CGE. Hydrocephalus was seen on the untreated side in the 90 CGE animal likely because of mass effect, while it was seen in small degrees in the side of treatment in the 70 and 50 CGE animals. Histopathology showed changes at 90 and 70 CGE, but not at 50 or 30 CGE at this time point using H and E stains. HRMAS showed spectroscopic changes in the surviving 90 and 70 CGE animals but not in the 50 and 30 CGE animals. Statistical significance was not reached because of the small sample size. Conclusions: Following single dose proton radiosurgery of rat hippocampus, HRMAS is able to identify metabolic changes induced by radiation. Studies built on these principles may help develop non-invasive MR spectroscopic methods to distinguish radiation changes from tumor recurrence.

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Section: Discussionmentioning

confidence: 61%

Section: Discussionmentioning

confidence: 99%

MR Spectroscopic Changes in the Rat Hippocampus following Proton Radiosurgery

Rabinov¹,

Cheng

Lee

et al. 2006

Stereotact Funct Neurosurg

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“…Omary et al [13] noted gadolinium enhancement at 4 weeks following a 120-Gy dose to rat brain tissue, but did not have T 2 -weighted imaging for comparison. Richards and Budinger [14] noted that Evans blue dye could be found in the brain surrounding brain tissue treated with doses of 50 Gy as early as 4 days, but more clearly at 3 months at both 30 Gy and 50 Gy. Karger et al [6] showed that there is a larger time delay to the onset of enhancement with lower doses.…”

Section: Discussionmentioning

confidence: 99%

MRI Changes in the Rat Hippocampus following Proton Radiosurgery

Rabinov¹,

Brisman²,

Cole

et al. 2004

Stereotact Funct Neurosurg

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Purpose: To define radiographic dose-response relationships for proton radiosurgery using a rat brain model. Methods and Materials: A group of 23 rats was treated with Bragg peak proton beam irradiation involving the right hippocampus. Single doses of 5, 12, 20, 30, 60, 90 and 130 cobalt gray equivalents (CGE) were delivered to groups of 3 animals using single fraction technique. One extra animal was included at the 130- and 30-CGE doses. Animals were imaged using a standard 1.5-tesla GE Signa MRI. A 3-inch surface coil was employed to obtain T₁-weighted sagittal images (TR 600 and TE 30) and dual echo T₂-weighted coronal images (TR 3,000 and TE 30/90). Animals were imaged at 1.5, 3, 4.5, 6 and 9 months. Volumetric analysis with custom software was done to evaluate areas of increased signal on T₂-weighted images, and signal change versus time curves were generated. Gadolinium-enhanced T₁-weighted imaging was also done at the 9-month time point to further evaluate tissue injury. The development of hydrocephalus was also examined. Results: Peak tissue injury was greater and occurred earlier with higher versus lower doses of radiation. Statistically significant differences were seen between the 130- and 90-CGE animals and between the 90- and 60-CGE animals (p < 0.0016) using ANOVA. Signal changes can be seen in at least 1 of the animals at 20 CGE. The largest volume of tissue enhancement at 9 months was seen in animals at 60 CGE, which may represent an intermediate zone of tissue injury and gliosis compared with greater tissue loss at higher doses and less injury at lower doses. Hydrocephalus developed first in the untreated hemisphere in 130- and 90-CGE animals as a result of mass effect while it occurred at a later time in the treated hemisphere in lower-dose animals. Conclusions: Following single-dose proton radiosurgery of rat hippocampus, serial MRIs show T₂ signal changes in animals ranging from 130 down to 20 CGE as well as the development of hydrocephalus. Dose-effect relationships using proton radiosurgery in rats will be a helpful step in guiding further studies on radiation injury to brain tissue.

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“…Cependant, compte tenu de l'énergie, une irradiation à dose trop élevée peut induire rapidement des lésions de coagulation. L'étude des modifications précoces induites par l'irradiation d'un hémi-cerveau de rat à des doses uniques de 15 à 50 Gy (hélium, 230 MeV), réalisée en IRM et en spectroscopie RMN du proton [43], montre assez bien que les lésions décrites et les altérations de la barrière hémato-astrocytaire ne sont pas représentatives de la radionécrose cérébrale différée. Ces lésions correspondent à la nécrose de coagulation telle qu'elle a été décrite après 40 Gy, dose unique, chez le rat [25].…”

Section: Dose Unique / Dose Fractionnée Et Anesthésie Des Animauxunclassified

“…En revanche, l'étude des temps de relaxation (7^ et T 2 ) en IRM, avec et sans injection de Gd-DTPA, 10 mois après l'irradiation de cerveau de lapin (hélium 230 MeV, doses uniques 15-30 Gy), fait apparaître une plus grande définition sur des images pondérées en T 2 et révèle des microlésions sur les images pondérées en 7", [34]. De même, l'intérêt d'aborder l'étude de la dégra-dation des lipides complexes de la glie par la spectroscopie RMN du proton a été démontré par Richards et Budinger [43] dans l'hémi-cerveau de rat juvénile normal, après irradiation à dose unique de 10-50 Gy (hélium 230 MeV). Par ailleurs, ces auteurs ont observé une augmentation du signal RMN dans l'hémi-cerveau controlatéral non irradié, observation que nous avions rapportée, également en IRM, dans un modèle d'irradiation musculaire localisée chez le lapin [33].…”

Section: Imagerieunclassified

La radionécrose cérébrale. Limites et perspectives des modèles expérimentaux

Lefaix

1992

Radioprotection

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RÉSUMÉLa radiothérapie, traitement efficace des tumeurs cérébrales, peut avoir plusieurs effets secondaires dont la radionécrose tardive. ABSTRACT Cerebral radiation necrosis is the major CNS hazard of clinical treatment therapy involving delivery of high doses of radiation to the brain. It is generally irreversible and frequently leads to death from brain necrosis. Necrosis has beenreported with total doses of 60 Gy, delivered in conventional fractions. Symptoms depend upon the volume of brain irradiated and are frequently those of an intracranial mass and may be present as an area of gliosis or frank necrosis. Possible causes include some direct effect of radiation on glial cells, vascular changes and the action of an immunological mechanism. The weight of evidence suggests that demyelination is important in the early delayed reaction, and that vascular changes gradually become more important in the late delayed reactions, from several months to years after treatment. The advent of sophisticated radiographic technologies such as computed tomography, magnetic resonance imaging and spectroscopy, and positron emission tomography have facilitated serial non invasive examination of morphologic or physiologic parameters within the brain after irradiation. Limits and prospects of these technologies are reviewed in experimental animal models of late radiation injuries of the brain, which were carried out in many species ranging from mouse to monkey.Commissariat à l'énergie atomique, Direction des sciences du vivant, Département de pathologie et toxicologie expérimentales, Laboratoire de radiobiologie appliquée, 91191 Gifsur-Yvette Cedex.

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NMR imaging and spectroscopy of the mammalian central nervous system after heavy ion radiation

Cited by 3 publications

References 21 publications

MR Spectroscopic Changes in the Rat Hippocampus following Proton Radiosurgery

MR Spectroscopic Changes in the Rat Hippocampus following Proton Radiosurgery

MRI Changes in the Rat Hippocampus following Proton Radiosurgery

La radionécrose cérébrale. Limites et perspectives des modèles expérimentaux

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