Cortical thickness analysis in temporal lobe epilepsy using fully Bayesian spectral method in magnetic resonance imaging

BACKGROUND

Temporal lobe epilepsy (TLE) is the most common type of epilepsy associated with changes in the cerebral cortex throughout the brain. Magnetic resonance imaging (MRI) is widely used for detecting such anomalies; nevertheless, it produces spatially correlated data that cannot be considered by the usual statistical models. This study aimed to compare cortical thicknesses between patients with TLE and healthy controls by considering the spatial dependencies across different regions of the cerebral cortex in MRI.

METHODS

In this study, T1-weighted MRI was performed on 20 healthy controls and 33 TLE patients. Nineteen patients had a left TLE and 14 had a right TLE. Cortical thickness was measured for all individuals in 68 regions of the cerebral cortex based on images. Fully Bayesian spectral method was utilized to compare the cortical thickness of different brain regions between groups. Neural networks model was used to classify the patients using the identified regions.

RESULTS

For the left TLE patients, cortical thinning was observed in bilateral caudal anterior cingulate, lateral orbitofrontal (ipsilateral), the bilateral rostral anterior cingulate, frontal pole and temporal pole (ipsilateral), caudal middle frontal and rostral middle frontal (contralateral side). For the right TLE patients, cortical thinning was only observed in the entorhinal area (ipsilateral). The AUCs of the neural networks for classification of left and right TLE patients versus healthy controls were 0.939 and 1.000, respectively.

CONCLUSION

Alteration of cortical gray matter thickness was evidenced as common effect of epileptogenicity, as manifested by the patients in this study using the fully Bayesian spectral method by taking into account the complex structure of the data.

Effect of Time Lapse on the Diagnostic Accuracy of Cone Beam Computed Tomography for Detection of Vertical Root Fractures

Accurate and early diagnosis of vertical root fractures (VRFs) is imperative to prevent extensive bone loss and unnecessary endodontic and prosthodontic treatments. The aim of this study was to assess the effect of time lapse on the diagnostic accuracy of cone beam computed tomography (CBCT) for VRFs in endodontically treated dog's teeth. Forty-eight incisors and premolars of three adult male dogs underwent root canal therapy. The teeth were assigned to two groups: VRFs were artificially induced in the first group (n=24) while the teeth in the second group remained intact (n=24). The CBCT scans were obtained by NewTom 3G unit immediately after inducing VRFs and after one, two, three, four, eight, 12 and 16 weeks. Three oral and maxillofacial radiologists blinded to the date of radiographs assessed the presence/absence of VRFs on CBCT scans. The sensitivity, specificity and accuracy values were calculated and data were analyzed using SPSS v.16 software and ANOVA. The total accuracy of detection of VRFs immediately after surgery, one, two, three, four, eight, 12 and 16 weeks was 67.3%, 68.7%, 66.6%, 64.6%, 64.5%, 69.4%, 68.7%, 68% respectively. The effect of time lapse on detection of VRFs was not significant (p>0.05). Overall sensitivity, specificity and accuracy of CBCT for detection of VRFs were 74.3%, 62.2%, 67.2% respectively. Cone beam computed tomography is a valuable tool for detection of VRFs. Time lapse (four months) had no effect on detection of VRFs on CBCT scans.

The comparison of scapular upward rotation and scapulohumeral rhythm between dominant and non-dominant shoulder in male overhead athletes and non-athletes

Previous studies have stated that the scapulohumeral rhythm dysfunction can make person prone to glenohumeral joint pathologies. The purpose of this study was to compare scapular upward rotation and scapulohumeral rhythm between dominant and non-dominant shoulder in male overhead athletes and non-athletes. Seventeen overhead athletes and seventeen non-athletes volunteered for this study. Two inclinometers were used to measure humeral abduction and scapular upward rotation in rest position, 45°, 90° and 135° humeral abduction in frontal plane. Findings indicated there was no significant asymmetry in scapular upward rotation and scapulohumeral rhythm in different abduction angles between dominant and non-dominant shoulder in non-athletes. In contrast, overhead athletes' dominant shoulders have more downward rotation in scapular rest position and more upward rotation in 90° and 135° shoulder abduction than non-dominant shoulders. Also, overhead athletes presented scapulohumeral rhythm asymmetry between dominant and non-dominant shoulder in 90° and 135° humeral abduction as dominant shoulders have less scapulohumeral rhythm ratio than non-dominant shoulders. Furthermore, overhead athletes dominant shoulders have more scapular downward rotation in scapular rest position, more scapular upward rotation in 90° and 135° humeral abduction and less scapulohumeral rhythm ratio in 45°, 90° and 135° humeral abduction than non-athletes in dominant shoulders. We suggest that clinicians should be aware that some scapular asymmetry may be common in some athletes. It should not be considered as a pathological sign but rather an adaptation to extensive use of upper limb.