Lactate and T 2 measurements of synovial aspirates at 1.5T: differentiation of septic from non-septic arthritis

Objective: The aim of this study was to differentiate septic from non-septic arthritis by measuring lactate concentration with 1H magnetic resonance spectroscopy (HMRS) and by estimating total protein content with the assessment of T 2 values. Materials and methods: In 30 patients with acute arthritis, synovial fluid was aspirated. Lactate concentrations were analyzed with single voxel HMRS at 1.5T. T 2 relaxation times were mapped with a multi-spin echo sequence. All samples underwent microbiological testing and routine laboratory analysis to quantify lactate concentration and total protein content. Values obtained in septic and non-septic arthritis were compared with a Mann-Whitney U test. Results: Synovial fluid from patients with septic arthritis (n = 10) had higher concentrations of lactate (11.4 ± 4.0mmol/L) and higher total protein content (51.8 ± 10.7g/L) than fluid obtained in non-septic arthritis (n = 20; 5.2 ± 1.1mmol/L and 40.4 ± 6.9g/L, respectively, p 6mmol/L) in combination with low T 2 values (<550ms) identify septic arthritis with a sensitivity of 70% and a specificity of 89%. Conclusion: Spectroscopic measurements of lactate concentration in combination with the estimation of protein content using T 2 may be of value in the differentiation of septic from non-septic arthriti

The effect of CSF drain on the optic nerve in idiopathic intracranial hypertension

Background: Elevation of intracranial pressure in idiopathic intracranial hypertension induces an edema of the prelaminar section of the optic nerve (papilledema). Beside the commonly observed optic nerve sheath distention, information on a potential pathology of the retrolaminar section of the optic nerve and the short-term effect of normalization of intracranial pressure on these abnormalities remains scarce. Methods: In this exploratory study 8 patients diagnosed with idiopathic intracranial hypertension underwent a MRI scan (T2 mapping) as well as a diffusion tensor imaging analysis (fractional anisotropy and mean diffusivity). In addition, the clinical presentation of headache and its accompanying symptoms were assessed. Intracranial pressure was then normalized by lumbar puncture and the initial parameters (MRI and clinical features) were re-assessed within 26 h. Results: After normalization of CSF pressure, the morphometric MRI scans of the optic nerve and optic nerve sheath remained unchanged. In the diffusion tensor imaging, the fractional anisotropy value was reduced suggesting a tissue decompression of the optic nerve after lumbar puncture. In line with these finding, headache and most of the accompanying symptoms also improved or remitted within that short time frame. Conclusion: The findings support the hypothesis that the elevation of intracranial pressure induces a microstructural compression of the optic nerve impairing axoplasmic flow and thereby causing the prelaminar papilledema. The microstructural compression of the optic nerve as well as the clinical symptoms improve within hours of normalization of intracranial pressure

Structural Olfactory Nerve Changes in Patients Suffering from Idiopathic Intracranial Hypertension

BACKGROUND: Complications of idiopathic intracranial hypertension (IIH) are usually caused by elevated intracranial pressure (ICP). In a similar way as in the optic nerve, elevated ICP could also compromise the olfactory nerve system. On the other side, there is growing evidence that an extensive lymphatic network system around the olfactory nerves could be disturbed in cerebrospinal fluid disorders like IIH. The hypothesis that patients with IIH suffer from hyposmia has been suggested in the past. However, this has not been proven in clinical studies yet. This pilot study investigates whether structural changes of the olfactory nerve system can be detected in patients with IIH. METHODOLOGY/PRINCIPAL FINDINGS: Twenty-three patients with IIH and 23 matched controls were included. Olfactory bulb volume (OBV) and sulcus olfactorius (OS) depth were calculated by magnetic resonance techniques. While mean values of total OBV (128.7±38.4 vs. 130.0±32.6 mm(3), p=0.90) and mean OS depth (8.5±1.2 vs. 8.6±1.1 mm, p=0.91) were similar in both groups, Pearson correlation showed that patients with a shorter medical history IIH revealed a smaller OBV (r=0.53, p<0.01). In untreated symptomatic patients (n=7), the effect was greater (r=0.76, p<0.05). Patients who suffered from IIH for less than one year (n=8), total OBV was significantly smaller than in matched controls (116.6±24.3 vs. 149.3±22.2 mm(3), p=0.01). IIH patients with visual disturbances (n=21) revealed a lower OS depth than patients without (8.3±0.9 vs. 10.8±1.0 mm, p<0.01). CONCLUSIONS/SIGNIFICANCE: The results suggest that morphological changes of the olfactory nerve system could be present in IIH patients at an early stage of disease

Quantitative MRI methods for the evaluation of cartilage quality

Quantitative MR-tomographische Verfahren wie T2-mapping oder die kontrastmittelverstärkte Knorpelbildgebung sind in der klinischen Routine sehr hilfreich zur Beurteilung der Knorpelqualität. In vielen experimentellen Studien wurde das Potential dieser Verfahren bereits demonstriert. Für den klinischen Einsatz werden jedoch häufig vereinfachte Annahmen gemacht, die zu systematischen Fehlern bei der Quantifizierung des makromolekularen Gehaltes in der Knorpelmatrix führen. Es konnte gezeigt werden, dass die Verteilung der T1 Relaxationszeiten im nativen Gelenkknorpel sehr inhomogen über die Knorpeldicke ist, der Einfluss von MR-Kontrastmitteln auf die T2 Relaxationszeit des Gelenkknorpel nicht vernachlässigbar ist und die intrakartilaginäre Akkumulation von Gadopentetate Dimeglumine Molekülen vom Proteoglykangehalt und der Integrität des Kollagenfasergerüstes abhängig ist. In der klinischen Routine ist mit den genannten Verfahren eine Abschätzung des Makromolekulargehaltes der Knorpelmatrix möglich.Quantitative MRI techniques like T2-mapping or contrast enhanced cartilage imaging are very useful in clinical routine to evaluate cartilage quality. In many experimental studies the potential of these methods has been demonstrated. In clinical routine several simplifying assumptions were made, leading to substantial biases in the quantification of cartilage macromolecular content. It has been shown that the distribution of T1 relaxation time in native cartilage is very inhomogeneous across cartilage thickness, the influence of MR contrast media on cartilage T2 is not neglectable and that the accumulation of gadopentetate dimeglumine depends on the proteoglycan content and the integrity of the collagen network. In clinical routine cartilage macromolecular content can be estimated with these methods

T2-weighted high-resolution coronal images of the olfactory bulb and sulcus olfactorius.

<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0035221#pone-0035221-g001" target="_blank">Figure 1A and 1B</a> show T2-weighted fast spin echo (FSE) sequences. In <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0035221#pone-0035221-g001" target="_blank">Figure 1A</a> the white arrows indicate the normal dimensioned right and left bulb olfactorius. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0035221#pone-0035221-g001" target="_blank">Figure 1B</a> demonstrates the calculation of the olfactory sulcus (OS) depth. The distance of the deepest point of the OS was determined using a tangent line from the border of the gyrus rectus to the internal orbital gyrus.</p

Characteristics of participants and results of morphological features of olfactory nerve system.

<p>Numerical data are presented as mean ± standard deviation (minimum-maximum)*, categorical data as numbers (n) and percent (%). The chi-square test was used for gender and independent T-test was used for numerical variables. Diagnosis of IIH=time between onset of first symptoms and enrolment in the study. Highest and last ICP=Highest and last intracranial pressure in the medical history of patients. CSF=Cerebrospinal fluid. Medication = Current intake of acetazolamide, topiramate or furosemide to treat IIH. OBV=Olfactory bulb volume. OS=Olfactory sulcus. *Numerical data of diagnosis of IIH are presented as median (range: minimum-maximum) because the data were not normally distributed.</p

Correlation among clinical features of IIH patients.

<p>Left chart, correlation between total OBV and the time between initial diagnosis of IIH and MRI scan in all IIH patients (n=23). Right chart, Pearson correlation between total olfactory bulb volume (OBV) and the time between initial diagnosis of IIH and MRI scan in untreated symptomatic patients (n=7).</p