Aim:The aim of the present study is to evaluate diffusion tensor tractography (DTT) as a tool for detecting diffuse axonal injury in patients of acute, mild, and moderate traumatic brain injury (TBI), using two diffusion variables: Fractional anisotropy (FA) and mean diffusivity (MD). The correlation of these indices with the severity of post-concussive symptoms was also assessed.Materials and Methods:Nineteen patients with acute, mild, or moderate TBI and twelve age- and sex-matched healthy controls were recruited. Following Magnetic Resonance Imaging (MRI) on a 3.0-T scanner, DTT was performed using the ‘fiber assignment by continuous tracking’ (FACT) algorithm for fiber reconstruction. Appropriate statistical tools were used to see the difference in FA and MD values between the control and patient groups. In the latter group, the severity of post-concussive symptoms was assessed six months following trauma, using the Rivermead Postconcussion Symptoms Questionnaire (RPSQ).Results:The patients displayed significant reduction in FA compared to the controls (P < 0.05) in several tracts, notably the corpus callosum, fornix, bilateral uncinate fasciculus, and bilateral superior thalamic radiations. Changes in MD were statistically significant in the left uncinate, inferior longitudinal fasciculus, and left posterior thalamic radiation. A strong correlation between these indices and the RPSQ scores was observed in several white matter tracts.Conclusion:Diffusion tensor imaging (DTI)-based quantitative analysis in acute, mild, and moderate TBI can identify axonal injury neuropathology, over and above that visualized on conventional MRI scans. Furthermore, the significant correlation observed between FA and MD indices and the severity of post-concussive symptoms could make it a useful predictor of the long-term outcome.
Neonatal bacterial meningitis is a common manifestation of late onset neonatal sepsis. Cranial sonography (CRS) has a crucial role in assessment of infants with clinical suspicion of bacterial meningitis as well as follows up of its complications. CRS is performed with high frequency transducer through anterior fontanelle in both coronal and sagittal planes. Various sonographic findings range from echogenic and widened sulci, ventriculomegaly, ventriculitis, hydrocephalus, extra-axial fluid collections, cerebritis and brain abscess. Sonography is extremely beneficial in evaluating intraventricular contents, especially debris and intraventricular septations. Linear high frequency probe along with color Doppler interrogation are of utmost importance in evaluating extra-axial fluid collection and helps differentiating it from benign subarachnoid space enlargement. Due to low cost, easy portability, speed of imaging, no need for sedation and above all lack of ionizing radiation make it superior to other cross sectional imaging, like CT and MRI, in evaluation of these sick neonates. Apart from textbooks, there is paucity of recently available literature on cranial sonographic findings in neonatal meningitis. This article is written with an educational intent to review the spectrum of findings in neonatal meningitis, with stress on findings that will be beneficial in the clinical practice.
We report the selection of Clostridium difficile resistant to the rifamycin class of antibiotics in a patient within 32 h of receiving rifaximin for the treatment of recurrent C. difficile diarrhea. Resistance was associated with single nucleotide substitutions within rpoB.A 65-year-old male outpatient with an 18-month history of four earlier episodes of Clostridium difficile diarrhea, each treated with vancomycin, was diagnosed with a fifth episode. His symptoms began just 4 days after his last vancomycin treatment stopped. Rifaximin (200 mg three times a day) was begun 4 days later, on day 1 of this study. Neither fecal samples nor isolates from the earlier episodes were available for study.This research was approved by TechLab, Inc., Institutional Review Board (IRB) number 1 (registration number IRB00003505, IRB organization number IORG0002905). On day 1, after giving his informed consent, the patient provided frequent fecal samples for research only. The results of the research tests we report were not used to support the patient's clinical diagnosis or guide treatment decisions. C. difficile spores were cultured on cycloserinecefoxitin-fructose agar supplemented with sodium taurocholate. Four or five isolates from each sample were PCR ribotyped (9) and tested with Etest strips on brucella blood agar (7) for the MIC of rifampin (RIF). RIF and rifaximin are both members of the rifamycin class of antibiotics. Resistance to one indicates resistance to the other, and they may be used interchangeably when assaying MICs (8). rpoB , the rifamycin resistance-determining region (RRDR) of each of the four or five isolates per sample, was sequenced (1, 2). All isolates were of ribotype 056. All produced toxins A and B. None produced binary toxin. All were susceptible to vancomycin and moxifloxacin.On day 1, only sensitive (RIF MIC, 0.002 g/ml) isolates with a wild-type RRDR were recovered. Exposure to rifaximin led rapidly to the emergence of resistance, and within 32 h, only resistant (RIF MIC, Ն32 g/ml) isolates were found. The isolates had a C1506¡T substitution in rpoB, a single nucleotide polymorphism (SNP) resulting in the His502Tyr change seen in resistant C. difficile (8). As treatment continued, only resistant strains of ribotype 056 were seen, the original strain and a second strain with the C1506¡T substitution plus an additional C1488¡T substitution that encodes Pro496Ser. This second SNP within rpoB of C. difficile has not been reported before (7,8). Its effect on resistance is unknown. The patient was asymptomatic for about 2 weeks after taking rifaximin, although throughout that time, both strains of resistant ribotype 056 isolates persisted. Ribotype 056 isolates are not frequent in our studies (Ͻ2% of almost 2,000 isolates), nor does ribotype 056 RIF resistance appear widespread. These are the only RIF-resistant members of ribotype 056 in our collection of 41 isolates.On day 49, when the two resistant strains were still present, the diarrhea returned and 1 week later, a 10-day course of fidaxomicin wa...
As healthcare professionals continue to combat the coronavirus disease 2019 (COVID-19) infection worldwide, there is an increasing interest in the role of imaging and the relevance of various modalities. Since imaging not only helps assess the disease at the time of diagnosis but also aids evaluation of response to management, it is critical to examine the role of different modalities currently in use, such as baseline X-rays and computed tomography scans carefully. In this article, we will draw attention to the critical findings for the radiologist. Further, we will look at point of care ultrasound, an increasingly a popular tool in diagnostic medicine, as a component of COVID-19 management.
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