Magnetic resonance neurography of the head and neck: state of the art,anatomy, pathology and future perspectives

Magnetic resonance neurography allows for the selective visualization of peripheral nerves and is increasingly being investigated. Whereas in the past, the imaging of the extracranial cranial and occipital nerve branches was inadequate, more and more techniques are now available that do allow nerve imaging. This basic review provides an overview of the literature with current state of the art, anatomical landmarks and future perspectives. Furthermore, we illustrate the possibilities of the three-dimensional CRAnial Nerve Imaging (3D CRANI) MR-sequence by means of a few case studies.     

A systematic review on diagnostic test accuracy of magnetic resonance neurography versus clinical neurosensory assessment for post-traumatic trigeminal neuropathy in patients reporting neurosensory disturbance

Objectives:To perform a systematic review of published studies on diagnostic accuracy of magnetic resonance neurography (MRN) vs clinical neurosensory testing (NST) for post-traumatic trigeminal neuropathy (PTTN) in patients reporting neurosensory disturbances (NSD).Methods:Human studies except case reports, reviews, systematic reviews and meta-analyses were included. PubMed, Embase, Web of Science and Cochrane Library were consulted. Risk of bias assessment was conducted using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. Predetermined data extraction parameters were noted and summarized.Results:8 studies met eligibility criteria of which 7 were retrospective, representing 444 subjects. Most studies were at high risk of bias with low applicability concerns. Populations and objectives were divergent with a large variation in timing (3 days–17 years post injury) and parameters (multiple coil designs, fat suppression techniques, additional contrast agent) of MRI acquisition. T₂ weighted 3 T imaging with short echo times (2.2–100 ms) and fat suppression was applied in seven studies, techniques varied. Determination of sensitivity and specificity could not be performed due to the methodological variation between studies and lacking comparative data between index and reference tests. Based on limited data, PTTN correlated reasonably well between clinical assessment, intraoperative findings and MRN abnormalities (k = 0.57). Increased signal intensity correlated with persistency of neurosensory disturbances in one study. Intra- (ICC 0.914–0.927) and interobserver (k = 0.70–0.891) MRN variability was considered good to excellent. One retrospective study showed substantial impact of MRN on clinical decision making in one-third of patients.Conclusion:Currently, there is insufficient scientific knowledge to support or refute the use of MRN. Based on limited data, MRN seems promising and reliable in detection and grading of PTTN. Methodological issues underline the importance for prospective blinded studies with standardization of signal intensity calculation and rigorous reporting of MRI acquisition parameters.     

The effect of high-dose fluticasone propionate and budesonide on lung function and asthma exacerbations in patients with severe asthma.

The purpose of this study was to investigate the comparative efficacy and safety of equal doses of inhaled fluticasone propionate (FP) and inhaled budesonide (BUD) using their respective dry powder inhalers in a population of severe asthmatics requiring high doses of inhaled corticosteroid. This double-blind double-dummy parallel-group study compared the effects of 24 weeks of treatment with FP (2000 micrograms daily via a Diskhaler inhaler; Glaxo Wellcome, Evreux, France) and BUD (2000 micrograms daily via a Turbuhaler inhaler; Astra Pharmaceuticals, Rijswijka, Netherlands) on lung function and asthma exacerbations in 395 patients with asthma. FP was statistically significantly superior to BUD with respect to the percentage of symptom-free days (P = 0.02), the incidence of days free from rescue bronchodilator usage (P = 0.02) and the distribution of change in peak expiratory flow (PEF) expressed as a percentage of the predicted PEF (P = 0.04). During the treatment period FP was statistically significantly superior to BUD for change in forced expiratory volume in 1 sec (FEV1) at 8, 16 and 24 weeks, change in the median daytime symptom score during weeks 5-16, for incidence of symptom-free days and incidence of days free from rescue bronchodilator usage during weeks 17-24. There was no significant difference between FP and BUD with respect to the number of patients experiencing one or more asthma exacerbation (33.8 and 28.4% of patients, respectively). There was, however, evidence that the exacerbations were clinically less severe in patients treated with FP, in that the time to resolution was quicker (11.0 vs. 14.7 days; P = 0.035), mean duration of all exacerbations (for an individual patient) tended to be shorter (18.5 vs. 23.6 days; P = 0.12), the time off work was reduced (4.2 vs. 7.6 days; P = 0.012) and the lowest PEF recorded during the exacerbation was higher (301 vs. 263 l min-1; P = 0.07). There were no clinically relevant differences in the safety (serum cortisol levels, markers of bone turnover, adverse events) of FP and BUD at these microgram equivalent doses. The patients recruited into this study, in retrospect, probably had no need for such high doses of inhaled corticosteroid but, irrespective of this, FP at microgram equivalent doses showed evidence of superior efficacy to BUD with respect to lung function and severity of asthma exacerbations without producing any greater adverse systemic effect.