Magnetic resonance study on fractional anisotropy and neuronal metabolite ratios in peritumoral area of cerebral gliomas.

BACKGROUND AND OBJECTIVE: Cerebral gliomas have a tendency to infiltrate the surrounding brain tissue for several centimeters from the core of tumor. The usefulness of structural magnetic resonance (MR) sequences is limited because of their insensitivity for the detection of tumor cells outside the visible tumor border. The aim of this study was to investigate the validity and the repeatability of 2 functional MR methods: fractional anisotropy (FA) and spectroscopy in the assessment of the peritumoral area of cerebral gliomas. MATERIAL AND METHODS: Forty-five patients with histologically verified brain gliomas underwent diffusion tensor imaging (DTI) and MR spectroscopy (MRS). Metabolic ratios were calculated from choline (Cho), creatine (Cr), N-acetylaspartate (NAA), lactate/lipids (LL), myo-inositol (MI) spectroscopic values obtained within the tumor center, perifocal edema, and distant and contralateral normal-appearing white matter. DTI maps of FA were calculated at the same locations. RESULTS: A significant gradual increase of FA and a decrease of LL/Cr ratios from the tumor center to the normal-appearing white matter were observed. The Cho/Cr ratio was significantly lower in the distant normal-appearing white matter than in the perifocal edema and the tumor center. The NAA/Cr ratio was significantly reduced in the tumor center, perifocal edema, and distant normal-appearing white matter compared with the contralateral hemisphere. MRS and DTI measurements of glioma and peritumoral area had a high degree of repeatability. CONCLUSIONS: Our study shows that MRS and DTI measurements are reproducible. The combined use of Cho/Cr, LL/Cr, and FA measurements is a promising MR technique that provides valuable additional information about the location of glioma potential border.

Condylar and mandibular morphological criteria in the 2D and 3D MSCT imaging for patients with Class II division 1 subdivision malocclusion.

UNLABELLED: The condyle has a special multidirectional capacity for the growth and adaptive remodeling of temporomandibular joint (TMJ). Being part of TMJ structure, it plays an important role in the stability of long-term treatment results for orthodontic and orthognatic patients with Class II division 1 subdivision malocclusions. Several computed tomography (CT) investigation modes have been used to evaluate the craniofacial morphology and particularly, for TMJ. Dimensional images, acquired using new generation multislice CT (MSCT) and cone beam CT scanning data, are becoming increasingly popular in the clinical work and research. The aim of the study was to develop a new CT investigation protocol for the quantification of morphological structures and skeletal landmarks of condyle, procesus condylaris and mandible. For this purpose we created two dimensional (2D) and three dimensional (3D) reconstruction images from primary axial MSCT scans using IAC review and Transparent bone programms and acquired accordant measurements of condylar and mandibular structures. This technic allowed to get truly volumetric reflexion of the joint components in its real anatomical size and avoided the bony superimpositions. Our material included 12 patients with skeletal Class II division 1 subdivision malocclusion who had indications for combined orthodontic and orthognatic treatment. CT examination was performed before the start of treatment. For statistical analysis paired Student t-tests were applied to test the diferences of mean values and correlation coefficients were calculated to assess possible interrelations between measurements. The preliminary results showed weak corrrelation between condylar and mandibular measurements. More significant correlation was observed between procesus condylaris and mandible. It was a significant difference between right and left side in the height of procesus condylaris in patients without clinicaly relevant facial asymetry which could be considered in the individual planning of orthognatic treatment. CONCLUSION: The developed combined 2D and 3D MSCT investigation protocol for condylar and mandibular measurements provides precise and demonstrative quantitative images of condylar and mandibular structures and its dimensional relationships., which could be qualified as informative criteria for the individual treatment planning for patients with Class II division 1 subdivision malocclusion.