Metabolite and diffusion changes in the rat brain after Leksell Gamma Knife irradiation

✍ Scribed by Vít Herynek; Martin Burian; Daniel Jirák; Roman Liščák; Kateřina Náměstková; Milan Hájek; Eva Syková

• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: English
• Weight: 284 KB
• Volume: 52
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.20150

✦ Synopsis

Abstract

Our study describes the time course of necrotic damage to the rat brain resulting from Leksell Gamma Knife (LGK) irradiation at a dose that was previously considered to be subnecrotic. A lesion induced in the rat hippocampus by 35 Gy irradiation was monitored by MRI, MRS, and DW‐MRI for 16 months. T~2~‐weighted images revealed a large hyperintense area with an increased apparent diffusion coefficient of water (ADC~w~), which occurred 8 months after irradiation, accompanied by metabolic changes (increase of lactate (Lac) and choline (Cho), and decrease of creatine (Cr) and N‐acetyl aspartate (NAA), as determined by MRS) that indicated an edema. In two animals, the hyperintensity persisted and a postnecrotic cavity connected to enlarged lateral ventricles developed. In the rest of the animals, the hyperintensity started to decrease 9 months post‐irradiation (PI), revealing hypointense areas with a decreased ADC~w~. Histology confirmed the MRI data, showing either scar formation or the development of a postnecrotic cavity. Magn Reson Med 52:397–402, 2004. © 2004 Wiley‐Liss, Inc.