Impact of Brain Midline Respect During High-Definition MRI Image Acquisition on Real Voxel-Based and Indirect Hippocampal Volumetry Using the XYZ Geo Method.

• DOI: https://doi.org/10.22533/at.ed.15941042413125

• Palavras-chave: Midline Deviation, Magnetic Resonance Imaging, Direct Hippocampal Volumetry, Indirect Hippocampal Volumetry.

• Keywords: Midline Deviation, Magnetic Resonance Imaging, Direct Hippocampal Volumetry, Indirect Hippocampal Volumetry.

• Abstract:

  Objectives: to demonstrate the impact of the acquisition of thin-slice MRI images with midline deviation on hippocampal volumetry both direct by voxels and indirect by applying the XYZ Geo1 method. Method: prospective study, which took place between January 2020 and July 2022, of 100 Dominican adults, divided into a control group of 60 patients with normal cognition divided into 3 age groups (20-40, 41 to 60 and 61 to 80 years) and a case group of 40 patients complaining of cognitive problems (41 to 60 and 61 to 80 years). They were administered the Folstein Mini Mental State Examination (MMSE) adapted to Latino patients3 . All of them benefited from a 1.5 Tesla MRI with 1-1.5 mm slices for three-dimensional reconstruction including T1 sequences without contrast, FLAIR, T2 and TOF.  
  To determine the deviation from the midline of the MRI images, the Angulus software (May 2020 version) was used to calculate the Geometric Angulation of Anatomical Structures4 . The hippocampi were examined morphologically to determine if there was any asymmetry in each slice when compared with each other by simple inspection by the Principal Investigator (PI). Real volumetry was performed using voxels and theoretical volumetry using the XYZ Geo method1.  The time taken for each type of hippocampal volumetry was timed. The midline deviation in the MRI images measured in degree with Angulus software, the level of asymmetry inspected in the hippocampal image on each side of the midline, the time it took to perform real and indirect volumetry of each of the 200 hippocampi studied and the percentage of approach between each type of volumetry according to the degrees of midline deviation of the MRI images were correlated. The data collected was processed using measures of central tendency and dispersion in the Microsoft Excel 2016 platform.  Results: the data obtained showed that even in MRIs with no midline deviation there was 37.5% asymmetry on visual inspection of the hippocampi in the same slice. No impact was found between the degree of midline deviation of the MRI image and the percentage of closeness between the real and theoretical volumetries. Neither was the degree of midline deviation of the MRI images correlated with the execution time of the real volumetry using voxels or indirect volumetry using the XYZ Geo method. The asymmetry between the hippocampi, even with significant midline deviations, did not affect the execution time of the actual volumetry. Conclusion: There is a significant degree of morphological asymmetry between the hippocampi when inspected in the same slice, independent of the degree of midline deviation of the MRI images. Neither the degree of deviation from the midline of these images, nor the asymmetry between the hippocampi inspected in each slice impact the quality or accuracy of direct or indirect volumetry, nor its execution time.