A statistical investigation of normal regional intra-subject heterogeneity of brain metabolism and perfusion by F-18 FDG and O-15 H2O PET imaging

Background

The definite evaluation of the regional cerebral heterogeneity using perfusion and metabolism by a single modality of PET imaging has not been well addressed. Thus a statistical analysis of voxel variables from identical brain regions on metabolic and perfusion PET images was carried out to determine characteristics of the regional heterogeneity of F-18 FDG and O-15 H₂O cerebral uptake in normal subjects.

Methods

Fourteen normal subjects with normal CT and/or MRI and physical examination including MMSE were scanned by both F-18 FDG and O-15 H₂O PET within same day with head-holder and facemask. The images were co-registered and each individual voxel counts (Q) were normalized by the gloabl maximal voxel counts (M) as R = Q/M. The voxel counts were also converted to z-score map by z = (Q - mean)/SD. Twelve pairs of ROIs (24 total) were systematically placed on the z-score map at cortical locations 15-degree apart and identically for metabolism and perfusion. Inter- and intra-subject correlation coefficients (r) were computed, both globally and hemispherically, from metabolism and perfusion: between regions for the same tracer and between tracers for the same region. Moments of means and histograms were computed globally along with asymmetric indices as their hemispherical differences.

Results

Statistical investigations verified with data showed that, for a given scan, correlation analyses are expectedly alike regardless of variables (Q, R, z) used. The varieties of correlation (r's) of normal subjects, showing symmetry, were mostly around 0.8 and with coefficient of variations near 10%. Analyses of histograms showed non-Gaussian behavior (skew = -0.3 and kurtosis = 0.4) of metabolism on average, in contrast to near Gaussian perfusion.

Conclusion

The co-registered cerebral metabolism and perfusion z maps demonstrated regional heterogeneity but with attractively low coefficient of variations in the correlation markers.     

Cynomorium songaricum extract enhances novel object recognition, cell proliferation and neuroblast differentiation in the mice via improving hippocampal environment

Background

Increasing numbers of reports show the beneficial effects of listening to Mozart music in decreasing epileptiform discharges as well as seizure frequency in epileptic children. There has been no effective method to reduce seizure recurrence after the first unprovoked seizure until now. In this study, we investigated the effect of listening to Mozart K.448 in reducing the seizure recurrence rate in children with first unprovoked seizures.

Methods

Forty-eight children who experienced their first unprovoked seizure with epileptiform discharges were included in the study. They were randomly placed into treatment (n?=?24) and control (n?=?24) groups. Children in the treatment group listened to Mozart K.448 daily before bedtime for at least six months. Two patients in the treatment group were excluded from analysis due to discontinuation intervention. Finally, forty-six patients were analyzed. Most of these patients (89.1%) were idiopathic in etiology. Seizure recurrence rates and reduction of epileptiform discharges were compared.

Results

The average follow-up durations in the treatment and control groups were 18.6?±?6.6 and 20.1?±?5.1 months, respectively. The seizure recurrence rate was estimated to be significantly lower in the treatment group than the control group over 24 months (37.2% vs. 76.8%, p?=?0.0109). Significant decreases in epileptiform discharges were also observed after 1, 2, and 6 months of listening to Mozart K.448 when compared with EEGs before listening to music. There were no significant differences in gender, mentality, seizure type, and etiology between the recurrence and non-recurrence groups.

Conclusions

Although the case number was limited and control music was not performed in this study, the study revealed that listening to Mozart K.448 reduced the seizure recurrence rate and epileptiform discharges in children with first unprovoked seizures, especially of idiopathic etiology. We believe that Mozart K.448 could be a promising alternative treatment in patients with first unprovoked seizures and abnormal EEGs. Further large-scaled study should be conducted to confirm the effect.

Trial registration

NCT01892605, date: June-19-2013     

Comparison of manual and semi-automated delineation of regions of interest for radioligand PET imaging analysis

Background

As imaging centers produce higher resolution research scans, the number of man-hours required to process regional data has become a major concern. Comparison of automated vs. manual methodology has not been reported for functional imaging. We explored validation of using automation to delineate regions of interest on positron emission tomography (PET) scans. The purpose of this study was to ascertain improvements in image processing time and reproducibility of a semi-automated brain region extraction (SABRE) method over manual delineation of regions of interest (ROIs).

Methods

We compared 2 sets of partial volume corrected serotonin 1a receptor binding potentials (BPs) resulting from manual vs. semi-automated methods. BPs were obtained from subjects meeting consensus criteria for frontotemporal degeneration and from age- and gender-matched healthy controls. Two trained raters provided each set of data to conduct comparisons of inter-rater mean image processing time, rank order of BPs for 9 PET scans, intra- and inter-rater intraclass correlation coefficients (ICC), repeatability coefficients (RC), percentages of the average parameter value (RM%), and effect sizes of either method.

Results

SABRE saved approximately 3 hours of processing time per PET subject over manual delineation (p < .001). Quality of the SABRE BP results was preserved relative to the rank order of subjects by manual methods. Intra- and inter-rater ICC were high (>0.8) for both methods. RC and RM% were lower for the manual method across all ROIs, indicating less intra-rater variance across PET subjects' BPs.

Conclusion

SABRE demonstrated significant time savings and no significant difference in reproducibility over manual methods, justifying the use of SABRE in serotonin 1a receptor radioligand PET imaging analysis. This implies that semi-automated ROI delineation is a valid methodology for future PET imaging analysis.     

Comparison of Technetium-99m-MIBI imaging with MRI for detection of spine involvement in patients with multiple myeloma

Background

Lewy body disease is, after Alzheimer's disease, the second most common cause of senile degenerative dementia with progressive cognitive deterioration, fluctuation of cognitive and motoric functions and psychotic symptoms. It is characterized histologically by the occurrence of Lewy bodies in allocortical, neocortical and subcortical structures. The aim of this study was to measure the cortical glucose metabolism using FDG PET (2-[18F]fluoro-2-deoxy-D-glucose position emission tomography) compared to normal subjects.

Patients and Methods

Five patients (5 m, mean age 75 y) with clinically suspected diffuse Lewy body disease (DLB) were studied with FDG PET. PET studies of the head were performed with a Siemens ECAT-ART PET-scanner with attenuation correction using 137-Cs point sources.

Results

We found the same distribution pattern of diffuse glucose hypometabolism in the entire cortical region with relative sparing of the primary sensory-motor cortex in all the patients. The few cases reported in the literature so far describe findings similar to ours.

Conclusion

The pattern of diffuse glucose hypometabolism in the entire cortex including the occipital region seems to be a typical feature of DLB that is distinctive from dementia of Alzheimer's disease.     

Tuberculosis associated immune reconstitution inflammatory syndrome in patients infected with HIV: meningitis a potentially life threatening manifestation

Background

Tuberculosis (TB) is the most common co infection in HIV-infected persons in India, requiring concomitant administration of anti TB and antiretroviral therapies. Paradoxical worsening of tuberculosis after anti-retroviral therapy (ART) initiation is frequently seen.

Objective

To study the frequency, clinical presentation and outcome of paradoxical tuberculosis associated immune reconstitution inflammatory syndrome (TB-IRIS) in HIV infected patients in a TB hospital in North India.

Design

A retrospective chart review of HIV-infected TB patients on anti-tubercular treatment (ATT) at time of ART initiation over a 3?year period. Medical records were reviewed for clinical manifestations and outcome in patients who developed TB-IRIS.

Results

514 HIV-infected patients were enrolled between January 2006 and December 2008. Thirteen (12.6%) of 103 patients who had received ART and ATT simultaneously developed paradoxical TB-IRIS. Clinical presentations of paradoxical TB-IRIS included new lymphadenopathy (n?=?3), increase in size of existing lymphadenopathy (n?=?3), worsening of existing pulmonary lesions (n?=?2), appearance of new pleural effusion (n?=?1) and prolonged high grade fever (n?=?2). Four patients developed new tubercular meningitis as manifestation of TB-IRIS. Our cases developed TB-IRIS a median of 15?days after starting ART (IQR 15?C36). TB-IRIS patients were older (> 35?years) than those with no IRIS (P?=?0.03), but were not distinguishable by CD4 T-cell count, duration of ATT before ART or the outcome of TB treatment. Eight (62%) patients had a complete recovery while 5 (38%) patients with TB-IRIS died, of which majority (n?=?3) had meningitis.

Conclusions

Paradoxical TB-IRIS is a frequent problem during concomitant ATT and ART in HIV-TB co infected patients in north India. Meningitis is a potentially life threatening manifestation of TB-IRIS.     

A mathematical model for carbon dioxide elimination: an insight for tuning mechanical ventilation

Purpose

The aim is to provide better understanding of carbon dioxide ( $\mathrm{CO}_2$ ) elimination during ventilation for both the healthy and atelectatic condition, derived in a pressure-controlled mode. Therefore, we present a theoretical analysis of $\mathrm{CO}_2$ elimination of healthy and diseased lungs.

Methods

Based on a single-compartment model, $\mathrm{CO}_2$ elimination is mathematically modeled and its contours were plotted as a function of temporal settings and driving pressure. The model was validated within some level of tolerance on an average of 4.9 % using porcine dynamics.

Results

$\mathrm{CO}_2$ elimination is affected by various factors, including driving pressure, temporal variables from mechanical ventilator settings, lung mechanics and metabolic rate.

Conclusion

During respiratory care, $\mathrm{CO}_2$ elimination is a key parameter for bedside monitoring, especially for patients with pulmonary disease. This parameter provides valuable insight into the status of an atelectatic lung and of cardiopulmonary pathophysiology. Therefore, control of $\mathrm{CO}_2$ elimination should be based on the fine tuning of the driving pressure and temporal ventilator settings. However, for critical condition of hypercapnia, airway resistance during inspiration and expiration should be additionally measured to determine the optimal percent inspiratory time (%TI) to maximize $\mathrm{CO}_2$ elimination for treating patients with hypercapnia.     

Estrogens regulate neuroinflammatory genes via estrogen receptors α and β in the frontal cortex of middle-aged female rats

Background

Increasing evidence links diverse forms of air pollution to neuroinflammation and neuropathology in both human and animal models, but the effects of long-term exposures are poorly understood.

Objective

We explored the central nervous system consequences of subchronic exposure to diesel exhaust (DE) and addressed the minimum levels necessary to elicit neuroinflammation and markers of early neuropathology.

Methods

Male Fischer 344 rats were exposed to DE (992, 311, 100, 35 and 0 μg PM/m³) by inhalation over 6 months.

Results

DE exposure resulted in elevated levels of TNFα at high concentrations in all regions tested, with the exception of the cerebellum. The midbrain region was the most sensitive, where exposures as low as 100 μg PM/m³ significantly increased brain TNFα levels. However, this sensitivity to DE was not conferred to all markers of neuroinflammation, as the midbrain showed no increase in IL-6 expression at any concentration tested, an increase in IL-1β at only high concentrations, and a decrease in MIP-1α expression, supporting that compensatory mechanisms may occur with subchronic exposure. Aβ42 levels were the highest in the frontal lobe of mice exposed to 992 μg PM/m³ and tau [pS199] levels were elevated at the higher DE concentrations (992 and 311 μg PM/m³) in both the temporal lobe and frontal lobe, indicating that proteins linked to preclinical Alzheimer's disease were affected. α Synuclein levels were elevated in the midbrain in response to the 992 μg PM/m³ exposure, supporting that air pollution may be associated with early Parkinson's disease-like pathology.

Conclusions

Together, the data support that the midbrain may be more sensitive to the neuroinflammatory effects of subchronic air pollution exposure. However, the DE-induced elevation of proteins associated with neurodegenerative diseases was limited to only the higher exposures, suggesting that air pollution-induced neuroinflammation may precede preclinical markers of neurodegenerative disease in the midbrain.     

A revised classification of the temporal branches of the posterior cerebral artery

Purpose

Understanding the vascular variability of the inferior temporal occipital regions is essential for microsurgical approaches to this cerebral zone. To this end, we carried out a microanatomical study of the inferior temporal cortical branches of the posterior cerebral artery (PCA) in order to define their vascularisation territories.

Methods

We studied 40 cerebral hemispheres (20 brains) under an operating microscope. Three brains were fixed in Winkler’s solution with latex arterial perfusion and the other 17 brains were fixed in formaldehyde solution.

Results

Our revised classification was based on the following findings. First, the anterior hippocampal artery was always associated with the anterior temporal artery, with the two sharing the vascularisation of the anterior part of the inferior temporal lobe. Second, the middle hippocampal and middle temporal arteries were never present together. Third, the presence of an anterior temporal artery always involved the presence of a posterior temporal artery. Hence, we classified the temporal branches of the PCA into three new patterns. The first pattern includes the anterior and posterior temporal arteries without the anterior hippocampal artery. The second pattern includes the anterior hippocampal artery and anterior and posterior temporal arteries. The third pattern includes the common temporal artery. The first pattern was found most frequently (n?=?23, 57.5%), followed by the second (n?=?9, 22.5%) and third patterns (n?=?8, 20%).

Conclusions

We propose a revised classification of the inferior temporal branches of the PCA that takes into account their vascularisation territories.     

A gene-wide investigation on polymorphisms in the taste receptor 2R14 (TAS2R14) and susceptibility to colorectal cancer

Background

Obsessive-compulsive disorder (OCD) is a clinically and etiologically heterogeneous syndrome. The high frequency of obsessive-compulsive symptoms reported in subjects with the 22q11.2 deletion syndrome (DiGeorge/velocardiofacial syndrome) or Prader-Willi syndrome (15q11-13 deletion of the paternally derived chromosome), suggests that gene dosage effects in these chromosomal regions could increase risk for OCD. Therefore, the aim of this study was to search for microrearrangements in these two regions in OCD patients.

Methods

We screened the 15q11-13 and 22q11.2 chromosomal regions for genomic imbalances in 236 patients with OCD using multiplex ligation-dependent probe amplification (MLPA).

Results

No deletions or duplications involving 15q11-13 or 22q11.2 were identified in our patients.

Conclusions

Our results suggest that deletions/duplications of chromosomes 15q11-13 and 22q11.2 are rare in OCD. Despite the negative findings in these two regions, the search for copy number variants in OCD using genome-wide array-based methods is a highly promising approach to identify genes of etiologic importance in the development of OCD.     

The hazards of lack of co-registration of ictal brain SPECT with MRI: A case report of sinusitis mimicking a brainstem seizure focus

Background

Single photon emission computed tomography (SPECT) following injection of radiotracer during a seizure is known as ictal SPECT. Comparison of an ictal SPECT study to a baseline or interictal study can aid identification of a seizure focus.

Case presentation

A young woman with encephalitis and refractory seizures underwent brain SPECT during a period of frequent seizure-like episodes, and during a seizure-free period. A focal area of increased radiotracer uptake present only when she was experiencing frequent seizure-like episodes was originally localized to the brainstem, but with later computerized co-registration of SPECT to MRI, was found to lie outside the brain, in the region of the sphenoid sinus.

Conclusion

Low-resolution SPECT images present difficulties in interpretation, which can be overcome through co-registration to higher-resolution structural images.     

Over-expression of caveolin-1 aggravate LPS-induced inflammatory response in AT-1 cells via up-regulation of cPLA2/p38 MAPK

Objective and design

The aim of this study was to study the effect of caveolin-1 on the cytosolic phospholipase A2 (cPLA2), p38 mitogen-activated protein kinase (p38 MAPK) and nuclear factor κB (NF-κB) in mouse lung alveolar type-1 cells' (AT-1 cells) inflammatory response induced by LPS.

Materials and methods

Gene clone technique was used to over-express caveolin-1 in AT-1 cells by lentivirus vector. The level of tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), cPLA2, p38 MAPK and NF-κB was measured by ELISA, western blotting and EMSA.

Treatment

AT-1 cells were treated with LPS.

Results

Over-expression of caveolin-1 not only increased the production of pro-inflammatory cytokine TNF-α and IL-6, but also enhanced the expression of the cPLA2, p38 MAPK, and NF-κB.

Conclusions

Our data demonstrated that over-expression of caveolin-1 aggravates the AT-1 injury induced by LPS, involving in modulation of the cPLA2 mediated by the cPLA2/p38 MAPK pathway.     

Changes in Illness Perceptions and Quality of Life During Participation in Cardiac Rehabilitation

Background

The beliefs patients hold about their disease and corresponding treatment have been shown to predict recovery in cardiac patients.

Purpose

However, it is not known to what extent these beliefs change during participation in cardiac rehabilitation and whether this is related to psychological indicators of outcome.

Method

Illness perceptions and health-related quality of life (HRQOL) were measured upon entry to (T0) and completion of (T1) a 3-month outpatient cardiac rehabilitation program in 158 cardiac patients.

Results

Repeated-measures ANOVA revealed that all illness perceptions other than timeline and personal control changed significantly over the course of cardiac rehabilitation. Overall, cardiac rehabilitation patients came to view their illness as more benign. Further analysis revealed that perceiving fewer emotional consequences of the illness, gaining a better understanding, and attributing fewer symptoms to the illness at the end of cardiac rehabilitation, was related to better HRQOL.

Conclusion

Illness perceptions change during cardiac rehabilitation and these changes are associated with enhanced quality of life. Clinical trials have shown illness beliefs in cardiac patients to be modifiable during hospital admission; our results suggest that cardiac rehabilitation may provide a second window of opportunity during which illness perceptions can be actively monitored and modified if maladaptive.     

High and dehiscent jugular bulb: clear and present danger during middle ear surgery

Purpose

Internal jugular vein is anatomic continuation of cranial dural sinuses in the neck region. During the course of skull base the first enlarged segment of jugular vein is described as jugular bulb. The aim of this study is to evaluate the jugular bulb abnormalities and define the risk of high and dehiscent jugular bulb injury during middle ear surgery.

Methods

This is a retrospective radiologic study of 1,010 patients (2,020 temporal bones) with various ear symptoms who had high resolution temporal bone computed tomography scans between 2007 and 2011.

Results

High jugular bulb was seen in 308 (15.2 %) temporal bones. Jugular bulb dehiscence was encountered in 153 (7.5 %) temporal bones. High jugular bulb and jugular bulb dehiscence were more common in the right ears and females. Forty-one (2 %) temporal bones revealed high and dehiscent jugular bulb which can be vulnerable during middle ear surgery. High and dehiscent jugular bulb was more common in the right ears and males. Male predominance becomes more significant in the left ears. Of the 308 temporal bones with high jugular bulb, 87 (28.2 %) also had coexisting carotid canal dehiscence.

Conclusion

High and dehiscent jugular bulb is an important anatomic variation that can result in catastrophic outcomes during middle ear surgery. Our series show that 2 % of patients can be considered in the “high-risk” group. Precise assessment of the preoperative computed tomography scans by both the radiologist and the ENT surgeon is of utmost importance. Preoperative awareness will minimize morbidity and mortality.     

Alpe d’HuZes Cancer Rehabilitation (A-CaRe) Research: Four Randomized Controlled Exercise Trials and Economic Evaluations in Cancer Patients and Survivors

Background

Previous studies showed that exercise in cancer patients is feasible and may reduce fatigue and improve physical fitness and quality of life. However, many previous studies had methodological weaknesses related to trial design, sample size, comparison group, outcome measures, short follow-up durations and programme content.

Purpose

This paper aims to present the rationale and design of the clinical research subprogramme of the Alpe d??HuZes Cancer Rehabilitation (A-CaRe) programme.

Method

A-CaRe Clinical Research includes four randomized controlled trials in patients: (a) after chemotherapy, (b) during chemotherapy, (c) after stem cell transplantation and (d) during childhood cancer. These trials compare high-intensity resistance and endurance exercise interventions with usual care or a waiting list control group. In two studies, a second intervention arm consisting of low-to-moderate intensity exercise is included. All four A-CaRe trials use similar methods.

Results

Outcome measures are carefully chosen based on the International Classification of Functioning Disability and Health model. Measurements will be performed prior to randomization (T0), after completion of the intervention (T1) and at follow-up (T2). The primary outcome measures are cardiorespiratory fitness, muscle strength and fatigue. Secondary outcome measures include health-related quality of life and psychosocial functioning. Furthermore, cost-effectiveness and cost-utility analyses are performed from a societal perspective.

Conclusion

We hypothesize that exercise is more effective at improving physical fitness and thereby reducing fatigue and more cost-effective compared with usual care or a waiting list control group. If so, the programmes will be implemented in the Dutch clinical practice.     

Implications of stress-induced genetic variation for minimizing multidrug resistance in bacteria

Background

Clinical experience suggests that many patients with Modic changes have relatively severe and persistent low back pain (LBP), which typically appears to be resistant to treatment. Exercise therapy is the recommended treatment for chronic LBP, however, due to their underlying pathology, Modic changes might be a diagnostic subgroup that does not benefit from exercise. The objective of this study was to compare the current state-of-the art treatment approach (exercise and staying active) with a new approach (load reduction and daily rest) for people with Modic changes using a randomized controlled trial design.

Methods

Participants were patients from an outpatient clinic with persistent LBP and Modic changes. They were allocated using minimization to either rest therapy for 10 weeks with a recommendation to rest for two hours daily and the option of using a flexible lumbar belt or exercise therapy once a week for 10 weeks. Follow-up was at 10 weeks after recruitment and 52 weeks after intervention and the clinical outcome measures were pain, disability, general health and global assessment, supplemented by weekly information on low back problems and sick leave measured by short text message (SMS) tracking.

Results

In total, 100 patients were included in the study. Data on 87 patients at 10 weeks and 96 patients at one-year follow-up were available and were used in the intention-to-treat analysis. No statistically significant differences were found between the two intervention groups on any outcome.

Conclusions

No differences were found between the two treatment approaches, 'rest and reduced load' and 'exercise and staying active', in patients with persistent LBP and Modic changes.

Trial Registration

ClinicalTrials.gov: NCT00454792     

Prevalence of bifid mandibular canals in panoramic radiographs: a maxillofacial surgical scope

Purpose

The present study aims to estimate the prevalence of bifid mandibular canals in patients treated at the Dental Clinic of the Federal University of Paraná, Brazil.

Methods

The sample consisted of 3,024 panoramic radiographs from male (n = 1,155) and female (n = 1,869) patients (mean age 30 years). An experienced radiologist analyzed the panoramic radiographs according to the study of Langlais et al. (J Am Dental Assoc 110:923–926, 1985), which classifies bifid mandibular canals into four different types.

Results

Sixty patients (1.98 %) presented bifid mandibular canals. Specifically, 50 patients revealed bifid mandibular canals type I, while 10 patients revealed bifid mandibular canals type II. All the variations were unilateral. In addition, statistically significant results were not observed for gender distribution.

Conclusion

The present findings indicate a low prevalence of morphologic alterations of the mandibular canal in the studied population. However, the present outcome highlights the clinical relevance of investigating the radiologic morphology of the mandibular canal prior to surgical interventions.     

Inhibition of p38 MAPK Reduces Expression of Vascular Endothelial Growth Factor in Allergic Airway Disease

Background

The p38 mitogen-activated protein kinase (MAPK) appears to play an important role in various pathophysiological responses and has been suggested to be involved in many processes considered critical to the inflammatory response and tissue remodeling. Bronchial asthma is a chronic inflammatory disorder of the airway accompanied by increased vascular permeability. Vascular endothelial growth factor (VEGF) is a potent stimulator of bronchial inflammation, airway remodeling, and physiologic dysregulation that augments antigen sensitization and T-helper type 2 cell (Th2)-mediated inflammation in allergic airway diseases. However, there are little data on the relationship between p38 MAPK signaling and VEGF expression in allergic airway disease.

Objective

This study aimed to investigate the role of p38 MAPK on the pathogenesis of allergic airway disease, more specifically in VEGF expression.

Methods

Using ovalbumin (OVA)-inhaled mice and a selective p38 MAPK inhibitor, SB 239063, the involvement of p38 MAPK in allergen-induced VEGF expression in the airway was evaluated.

Results

The increases of phosphorylation of p38 MAPK, VEGF protein expression, and vascular permeability in the lung after OVA inhalation were decreased substantially by the administration of SB 239063. In addition, SB 239063 significantly reduced the increase of Th2 cytokines and OVA-specific IgE. The inhibition of p38 MAPK or VEGF signaling prevented and also decreased the increases in the number of inflammatory cells and airway hyperresponsiveness in OVA-induced allergic airway disease.

Conclusions

These results indicate that inhibition of p38 MAPK may attenuate allergen-induced airway inflammation and vascular leakage through modulation of VEGF expression in mice.     

Rotation of the osseous spiral lamina from the hook region along the basal turn of the cochlea: results of a magnetic resonance image anatomical study using high-resolution DRIVE sequences

Purpose

To define the rotational anatomy of the osseous spiral lamina (OSL) at the hook region and along the basal turn of the cochlea and to illustrate the potential utility of high-resolution MRI images to study inner ear ultrastructure.

Methods

Retrospective review of high-resolution temporal bone MRI images in 20 consecutive adult patients referred for imaging unrelated to hearing loss. The main outcome measure utilised images in an oblique sagittal plane to measure the rotation of the OSL relative to the vertical axis in the hook region and along the basal turn of the cochlea.

Results

The right OSL is noted to rotate in a clockwise direction as one proceeds anteriorly; over the same distance, the left OSL rotates in an anti-clockwise direction. The average overall rotation for all subjects as measured over a distance of 1–7?mm from the posterior margin of the round window was 25.95°. Inter-subject variability was noted.

Conclusions

Prominent rotation of the OSL was noted in the hook region, this being most pronounced in the proximity to the round window. This concept may have implications for cochleostomy site selection with implant surgery. The study highlights the feasibility of high-resolution MRI to be used to systematically study variations in intra-cochlear anatomy.