Diffusion tensor imaging analysis with tract-based spatial statistics of the white matter abnormalities after epilepsy surgery.

INTRODUCTION: Diffusion tensor imaging (DTI) techniques demonstrated diffuse bilateral temporal and extra-temporal abnormalities of white matter in patients presenting mesial temporal lobe epilepsy with hippocampal sclerosis (HS). The aim of this study was to assess these diffusion changes following temporal lobe surgery, by applying a novel voxel-based tract-based spatial statistics (TBSS) technique for whole-brain analysis of fractional anisotropy (FA) and mean diffusivity (MD). Second, region-of-interest analysis (ROI) was performed to improve statistical power. MATERIAL AND METHODS: The study included 22 patients with unilateral HS. Twelve patients underwent temporal lobe surgery. Follow up MRI was done in a mean interval of 4 months. Voxelwise pre-operative FA asymmetry in all 22 patients was assessed within subjects between lesional and contralateral hemispheres. The whole-brain post-operative dataset of 10 seizure-free patients was compared with the corresponding pre-operative dataset using voxel-wise statistical analysis. Additionally, regional analysis at the fornices was done with skeleton-based region of interest (SROI). RESULTS: Within a mean interval time of 6.3 months after surgery, 10 of 12 patients were seizure free (83.3%). The voxelwise comparison between lesional and contralateral hemispheres was consistent with previous studies showing a more widespread diffusion alteration in the lesional hemisphere. Voxel-wise comparison between post and pre-operative dataset did not show supra-thresholded voxels. SROI statistical analysis showed significant decrease in FA and increase in MD in the ipsilateral fornix. Significant increase in FA was observed in the contralateral fornix after surgery. CONCLUSION: The ipsi-lesional fornix showed decreased FA and increased MD after surgery, consistent with Wallerian degeneration. In contrast, contra-lesional fornix demonstrated increase in FA. This observation is important for our understanding of the fate of the remaining brain tissue following removal of an epileptic focus. Postoperative increase in FA may reflect structural reorganization in response to epilepsy surgery. The discrepancy between SROI and voxelwise statistics emphasizes the difference of statistical sensitivity between voxelwise and ROI analyses.

Role of nasopharyngeal culture in antibiotic prescription for patients with common cold or acute sinusitis.

The aim of the present study was to assess the hypothesis that, when present in nasopharyngeal secretions, Streptococcus pneumoniae. Haemophilus influenzae, and Moraxella catarrhalis play a pathogenic role early in the course of an upper respiratory tract infection. Adults with a clinical diagnosis of acute sinusitis or common cold were enrolled. Participants were randomly assigned in a double-blind manner to receive azithromycin 500 mg daily or placebo for 3 days. The effect of treatment on symptom evolution in the predefined subset of patients with Streptococcus pneumoniae, Haemophilus influenzae, or Moraxella catarrhalis in their nasopharyngeal secretions was assessed. Of 265 patients enrolled, 132 received placebo and 133 azithromycin. Streptococcus pneumoniae, Haemophilus influenzae, or Moraxella catarrhalis was identified in nasopharyngeal secretions of 77 patients (29%). In this predefined subgroup of patients with Streptococcus pneumoniae, Haemophilus influenzae, or Moraxella catarrhalis, resolution of symptoms by day 7 occurred in 73% of those treated with azithromycin compared with 47% of those who received placebo (P=0.007). The median time before resolution of symptoms was 5 days in the azithromycin group compared to 7 days in the placebo group. Respiratory complications requiring antibiotic treatment occurred in 19% of patients in the placebo group and in 3% of the azithromycin group (P=0.025). In the remaining 188 patients without Streptococcus pneumoniae, Haemophilus influenzae, or Moraxella catarrhalis, resolution of symptoms by day 7 was similar in both groups (69% in the placebo group vs. 64% in the azithromycin group [P=0.75]). Antibiotic treatment is of clinical benefit for patients with acute sinusitis or common cold when Streptococcus pneumoniae, Haemophilus influenzae, or Moraxella catarrhalis is present in nasopharyngeal secretions. This observation provides new insights into the pathogenic role of these bacteria in the early stage of the common cold.

Anatomic relationship between arachnoid granulations in the transverse sinus and the termination of the vein of Labbé: an angiographic study.

We studied the anatomic relationship between arachnoid granulations in the transverse sinus and the termination of the vein of Labbé in 57 consecutive angiograms. Patients with pathology in intracranial venous structures or with inadequate image quality of the venous system were excluded. Arachnoid granulations were found in 12 of the 57 patients (21.1%), always at the junction of the vein of Labbé and the transverse sinus; the vein of Labbé was present in 55 patients (96.5%), most often without associated arachnoid granulations; the latter, however, were not observed in the absence of a vein of Labbé. This study confirms the close, constant anatomic relationship between arachnoid granulations in the transverse sinus and the termination of the vein of Labbé. This observation may help to differentiate arachnoid granulations from pathologic conditions involving the transverse sinus such as dural sinus thrombosis. The constant character of this relationship suggests a developmental role of afferent veins in the formation of arachnoid granulations.

[Symptoms and clinical and radiological signs predicting the bacterial origin of acute rhinosinusitis]. / Symptômes, signes cliniques et radiologiques prédictifs de l'origine bactérienne des rhino-sinusites aiguës.

A minority of patients with common cold and upper respiratory tract infections have a bacterial infection and may benefit from antibiotic therapy. The present analysis set out to determine whether there were clinical symptoms or signs which could help the clinician to identify a subset of patients with moderate forms of acute rhinosinusitis who are infected with pathogenic bacteria. Detailed clinical history and medical examination were obtained from 265 patients (mean age 35 years, 138 females and 127 males) presenting symptoms of upper respiratory tract infections but no fever above 38 degrees C. The presence of three pathogenic bacteria (S. pneumoniae, H. influenzae or M. catarrhalis) was determined in all patients by culture of nasopharyngeal secretions. Aggravating factors for severity of rhinosinusitis, such as severe nasal obstruction, inferior and/or middle turbinate hypertrophy, oedema of the middle meatus mucosa and septal defects, were not associated with the presence of bacteria. Pathogenic bacteria were found in 77 patients (29%). The clinical signs and symptoms which were significantly associated in a multivariate model with the presence of bacteria included facial pain (p < 0.003), coloured nasal discharge (p < 0.003) and radiological maxillary sinusitis (complete opacity, air-fluid level or mucosal thickening greater than 10 mm) (p < 0.002). This, the best predictive model, had a sensitivity of 69% and a specificity of 64% and therefore could not be used either as a screening tool or as a diagnostic criterion for bacterial rhinosinusitis. We conclude that signs and symptoms of acute rhinosinusitis in patients with a mild to moderate clinical presentation are poor predictors of the presence of bacteria. In agreement with previous studies, culture of nasopharyngeal secretions may identify patients who would benefit from antibiotic treatment. Thus, antibiotic therapy should not be prescribed in the absence of bacteriological evidence.

Twinkling artifact on intracerebral color Doppler sonography.

Transcranial Doppler sonography shows potential as a noninvasive technique for long-term follow-up of treated intracranial saccular aneurysms. This technical note describes a color Doppler artifact related to microcoil architecture that might represent a potential pitfall in transcranial Doppler sonographic evaluation of aneurysmal cavity thrombosis, since it may be wrongly interpreted as residual flow or aneurysmal cavity recanalization.