Feasibility of testing the effectiveness of a theory-informed intervention to reduce imaging for low back pain: a pilot cluster randomised controlled trial.

BACKGROUND: General medical practitioner (GP) recruitment and subsequent data collection in clinical practice are challenging and may limit successful completion of a large-scale trial. The aim of this study was to assess the feasibility of undertaking a cluster randomised controlled trial to test an intervention to reduce non-indicated imaging for low back pain in general medical practice. METHODS: A pilot cluster randomised controlled trial was performed, with recruitment of GPs and randomisation of GP clinics. All GPs attended a training session and were asked to record low back pain codes in electronic medical records for any low back pain presentations. Intervention group GPs were trained in the use of a patient education booklet to be used during low back pain patient visits. Control group GPs provided usual care. Outcomes for the proposed trial were collected to determine feasibility. GP recruitment was assessed as the proportion of GPs approached who consented to participate. Low back pain imaging outcomes were collected from electronic medical records (counts of patients presenting with low back pain) and from Australian healthcare administrative (Medicare) data (counts of imaging use). GP compliance with study procedures was assessed and qualitative data reported. RESULTS: Thirty-four GP clinics were approached, with four participating (12%). At these clinics, 13/19 (68%) GPs consented to participate, and 10/19 (53%) started the study. Outcome data were collected from medical records for all GPs. Three GPs (30%) withdrew consent to access Medicare data, limiting reporting of imaging outcome measures. Three GPs (30%) self-reported low compliance entering low back pain codes. CONCLUSIONS: This pilot cluster randomised controlled trial demonstrated the feasibility of many aspects of a full-scale effectiveness study, while also identifying a number of challenges that need to be resolved. Recommendations related to GP recruitment, study compliance, data collection, and outcome measures were made to increase the success of a future trial. TRIAL REGISTRATION: Australia and New Zealand Clinical Trials Register (ANZCTR), Trial ID: ACTRN12619000991112; Registered 11 July 2019, https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=376973.

General practitioner experiences using a low back pain management booklet aiming to decrease non-indicated imaging for low back pain.

BACKGROUND: Imaging is overused in the management of low back pain, resulting in overdiagnosis, increased healthcare utilisation, and increased costs. Few effective interventions to decrease inappropriate use have been developed and have typically not been developed using behaviour change theory. An intervention to reduce non-indicated imaging for low back pain was developed using behavioural change theory, incorporating a novel low back pain management booklet to facilitate patient education and reassurance. The aim of this study was to assess the adoption and feasibility of use of the developed intervention within clinical practice and to determine appropriate implementation strategies to address identified barriers to use. METHODS: Fourteen general medical practitioners were recruited and trained to use the booklet with low back pain patients over a minimum 5-month period. Quantitative data on use of the booklet were collected and analysed descriptively. Qualitative data on use of the booklet and training session were collected in general medical practitioner interviews and thematically analysed. Barriers to use were identified and mapped to suitable implementation strategies using the Behaviour Change Wheel. RESULTS: Practitioners used the booklet with 73 patients. The booklet was used with 63% of patients presenting with low back pain. Facilitators for using the booklet included patient's requesting imaging and lower practitioner confidence in managing low back pain. Barriers included accessible storage and remembering to use the booklet. Implementation strategies were identified to increase adoption and feasibility of use, including development of a digital version of the booklet. CONCLUSIONS: General medical practitioners reported that the low back pain management booklet and training were useful for clinical practice, particularly with patients requesting imaging. Barriers to use were identified and implementation strategies to address these barriers will be incorporated into future effectiveness studies. This study forms one of a series of studies to thoroughly develop and test an intervention to reduce non-indicated imaging for low back pain; a successful intervention would decrease healthcare costs and improve patient management.

Effect of combination inhaled therapy on ventilation distribution measured by SPECT/CT imaging in uncontrolled asthma.

Asthma is characterized by heterogeneous ventilation as measured by three-dimensional ventilation imaging. Combination inhaled corticosteroid/long-acting ß2-agonist (ICS/LABA) treatment response is variable in asthma, and effects on regional ventilation are unknown. Our aims were to determine whether regional ventilation defects decrease after ICS/LABA treatment and whether small airways dysfunction predicts response in uncontrolled asthma. Twenty-two symptomatic participants with asthma underwent single-photon emission computed tomography (SPECT)/CT imaging with Technegas, before and after 8-wk fluticasone/formoterol (1,000/40 µg/day) treatment. Lung regions that were nonventilated, low ventilated, or well ventilated were calculated using an adaptive threshold method and were expressed as a percentage of total lung volume. Multiple-breath nitrogen washout (MBNW) was used to measure diffusion-dependent and convection-dependent small airways function (Sacin and Scond, respectively). Forced oscillation technique (FOT) was used to measure respiratory system resistance and reactance. At baseline and posttreatment, Scond z-score was related to percentage of nonventilated lung, whereas Sacin z-score was related to percentage of low-ventilated lung. Although symptoms, spirometry, FOT, and MBNW improved following treatment, there was no mean change in ventilation measured by SPECT. There was, however, a wide range of changes in SPECT ventilation such that greater percentage of nonventilated lung, older age, and higher Scond predicted a reduction in nonventilated lung after treatment. SPECT ventilation defects are overall unresponsive to ICS/LABA, but the response is variable, with improvement occurring when small airways dysfunction and ventilation defects are more severe. Persistent ventilation defects that correlate with Scond suggest that mechanisms such as non-ICS responsive inflammation or remodeling underlie these defects.NEW & NOTEWORTHY This study provides insights into the mechanisms of high-dose ICS treatment in uncontrolled asthma. Ventilation defects as measured by SPECT/CT imaging respond heterogeneously to increased ICS/LABA treatment, with improvement occurring when ventilation defects and impairment of convection-dependent small airways function are more severe. Persistent correlations between ventilation defects and measures of small airways function suggest the potential presence of ICS nonresponsive inflammation and/or remodeling.

Application of deep learning for automatic segmentation of brain tumors on magnetic resonance imaging: a heuristic approach in the clinical scenario.

PURPOSE: Accurate brain tumor segmentation on magnetic resonance imaging (MRI) has wide-ranging applications such as radiosurgery planning. Advances in artificial intelligence, especially deep learning (DL), allow development of automatic segmentation that overcome the labor-intensive and operator-dependent manual segmentation. We aimed to evaluate the accuracy of the top-performing DL model from the 2018 Brain Tumor Segmentation (BraTS) challenge, the impact of missing MRI sequences, and whether a model trained on gliomas can accurately segment other brain tumor types. METHODS: We trained the model using Medical Decathlon dataset, applied it to the BraTS 2019 glioma dataset, and developed additional models using individual and multimodal MRI sequences. The Dice score was calculated to assess the model's accuracy compared to ground truth labels by neuroradiologists on BraTS dataset. The model was then applied to a local dataset of 105 brain tumors, performance of which was qualitatively evaluated. RESULTS: The DL model using pre- and post-gadolinium contrast T1 and T2 FLAIR sequences performed best, with a Dice score 0.878 for whole tumor, 0.732 tumor core, and 0.699 active tumor. Lack of T1 or T2 sequences did not significantly degrade performance, but FLAIR and T1C were important contributors. All segmentations performed by the model in the local dataset, including non-glioma cases, were considered accurate by a pool of specialists. CONCLUSION: The DL model could use available MRI sequences to optimize glioma segmentation and adopt transfer learning to segment non-glioma tumors, thereby serving as a useful tool to improve treatment planning and personalized surveillance of patients.

A Window Into the Whole Story: Temporal Bone Plasmacytoma Presenting With a Mobile Third Window.

A 63-year-old man presented with imbalance when coughing due to a respiratory tract infection. He had a history of multiple myeloma with a plasmacytoma of the left temporal bone. Examination revealed a positive leftward head impulse test, no spontaneous nystagmus, left-beating positional nystagmus, and left-beating Valsalva-induced nystagmus. Videonystagmography, audiology, and comprehensive vestibular function tests revealed a subtotal left peripheral audio-vestibular loss. Temporal bone computed tomography showed an unchanged bony erosion of the left labyrinth from 2 years prior. Vertigo subsided after treatment of the respiratory tract infection. Although no tumor progression was evident, coughing had triggered a preexisting third mobile window to declare itself. Laryngoscope, 131:E966-E969, 2021.

Bone-Conducted oVEMP Latency Delays Assist in the Differential Diagnosis of Large Air-Conducted oVEMP Amplitudes.

Background: A sensitive test for Superior Semicircular Canal Dehiscence (SCD) is the air-conducted, ocular vestibular evoked myogenic potential (AC oVEMP). However, not all patients with large AC oVEMPs have SCD. This retrospective study sought to identify alternate diagnoses also producing enlarged AC oVEMPs and investigated bone-conducted (BC) oVEMP outcome measures that would help differentiate between these, and cases of SCD. Methods: We reviewed the clinical records and BC oVEMP results of 65 patients (86 ears) presenting with dizziness or balance problems who underwent CT imaging to investigate enlarged 105 dB nHL click AC oVEMP amplitudes. All patients were tested with BC oVEMPs using two different stimuli (1 ms square-wave pulse and 8 ms 125 Hz sine wave). Logistic regression and odds ratios were used to determine the efficacy of BC oVEMP amplitudes and latencies in differentiating between enlarged AC oVEMP amplitudes due to dehiscence from those with an alternate diagnosis. Results: Fifty-three ears (61.6%) with enlarged AC oVEMP amplitudes were identified as having frank dehiscence on imaging; 33 (38.4%) had alternate diagnoses that included thinning of the bone covering (near dehiscence, n = 13), vestibular migraine (n = 12 ears of 10 patients), enlarged vestibular aqueduct syndrome (n = 2) and other causes of recurrent episodic vertigo (n = 6). BC oVEMP amplitudes of dehiscent and non-dehiscent ears were not significantly different (p > 0.05); distributions of both groups overlapped with the range of healthy controls. There were significant differences in BC oVEMP latencies between dehiscent and non-dehiscent ears for both stimuli (p < 0.001). A prolonged n1 125 Hz latency (>11.5 ms) was the best predictor of dehiscence (odd ratio = 27.8; 95% CI:7.0-111.4); abnormal n1 latencies were identified in 79.2% of ears with dehiscence compared with 9.1% of ears without dehiscence. Conclusions: A two-step protocol of click AC oVEMP amplitudes and 125 Hz BC oVEMP latency measures optimizes the specificity of VEMP testing in SCD.

Magnetic Resonance Spectroscopic Assessment of Isocitrate Dehydrogenase Status in Gliomas: The New Frontiers of Spectrobiopsy in Neurodiagnostics.

BACKGROUND: In the era of integrated genomic-histologic analysis of brain tumors, new biomarkers have been introduced as diagnostic, prognostic, and therapeutic indicators. The analysis of the mutation in the isocitrate dehydrogenase (IDH) genes IDH1 and IDH2 has provided important diagnostic and prognostic information for patients affected by diffuse glioma (i.e., the presence of the mutation has been related to an increased survival rate). The reference standard of IDH mutation detection has been its assessment in surgical specimens, immunohistochemistry, and/or genetic sequencing. Knowing the IDH status information preoperatively would be of great importance, because it has been related to tumor progression and the response to treatment. The oncometabolite 2-hydroxyglutarate (2HG), accumulated in gliomas with IDH mutation status, can be detected in vivo using magnetic resonance spectroscopy (MRS). METHODS: The 2HG-MRS technique remains technically challenging. We have summarized the results of the first pilot study in Australia, which included 10 patients affected by glioma. The data recorded from May 2017 to November 2018 were analyzed. RESULTS: In our exploratory study, we reached a sensitivity and specificity of 100%, confirming the strong predictive role of 2HG, as detected using MRS, in the diagnosis of glioma. CONCLUSION: In the present study, we have focused on methodological tips and future perspectives of the technique in the neuroimaging and neuro-oncological scenario. We would advocate the integration of 2HG-MRS into standard clinical practice.

Cerebellar Tissue Strain in Chiari Malformation with Headache.

OBJECTIVE: The pathogenesis of Chiari malformation type 1 (CM-1)-associated Valsalva headache is unknown, but it may be caused by abnormal cerebellar tonsil tissue strain. Advances in cardiac-gated magnetic resonance imaging (MRI) techniques such as balanced fast-field echo (bFFE) allow quantification of the motion of anatomic structures and can be used to measure tissue strain. The current study investigated the relationship between Valsalva heachache and tonsillar motion in patients with CM-1. METHODS: A retrospective review of patients with CM-1 who had undergone cardiac-gated bFFE MRI was performed. Headache symptoms were retrieved from the medical records. Anatomic landmarks were manually selected on the cine bFFE, and a validated motion-tracking software was used to assess motion over the cardiac cycle in patients at rest. For each patient, displacement, strain, and strain rate were calculated for 3 anatomic segments. Patients undergoing surgery were examined before and after surgery. RESULTS: From 88 patients, a total of 108 bFFE sequences were analyzed. Valsalva headache was present in 50% of patients. Cerebellar tonsil displacement (P = 0.003), strain (P = 0.012), and maximum strain rate (P = 0.04) were reduced after surgery (n = 20). There was no statistically significant association between tissue motion and headache symptoms. CONCLUSION: The results of this study do not support a relationship between cardiac cycle cerebellar strain and Valsalva headache in patients with CM-1. It is possible that cerebellar strain related to respiratory maneuvers is associated with headache in Chiari patients. Further investigation of tissue strain is warranted because it represents a potential biomarker for outcomes after surgery.

Using behaviour change theory and preliminary testing to develop an implementation intervention to reduce imaging for low back pain.

BACKGROUND: Imaging is overused in the management of low back pain (LBP). Interventions designed to decrease non-indicated imaging have predominantly targeted practitioner education alone; however, these are typically ineffective. Barriers to reducing imaging have been identified for both patients and practitioners. Interventions aimed at addressing barriers in both these groups concurrently may be more effective. The Behaviour Change Wheel provides a structured framework for developing implementation interventions to facilitate behavioural change. The aim of this study was to develop an implementation intervention aiming to reduce non-indicated imaging for LBP, by targeting both general medical practitioner (GP) and patient barriers concurrently. METHODS: The Behaviour Change Wheel was used to identify the behaviours requiring change, and guide initial development of an implementation intervention. Preliminary testing of the intervention was performed with: 1) content review by experts in the field; and 2) qualitative analysis of semi-structured interviews with 10 GPs and 10 healthcare consumers, to determine barriers and facilitators to successful implementation of the intervention in clinical practice. Results informed further development of the implementation intervention. RESULTS: Patient pressure on the GP to order imaging, and the inability of the GP to manage a clinical consult for LBP without imaging, were determined to be the primary behaviours leading to referral for non-indicated imaging. The developed implementation intervention consisted of a purpose-developed clinical resource for GPs to use with patients during a LBP consult, and a GP training session. The implementation intervention was designed to provide GP and patient education, remind GPs of preferred behaviour, provide clinical decision support, and facilitate GP-patient communication. Preliminary testing found experts, GPs, and healthcare consumers were supportive of most aspects of the developed resource, and thought use would likely decrease non-indicated imaging for LBP. Suggestions for improvement of the implementation intervention were incorporated into a final version. CONCLUSIONS: The developed implementation intervention, aiming to reduce non-indicated imaging for LBP, was informed by behaviour change theory and preliminary testing. Further testing is required to assess feasibility of use in clinical practice, and the effectiveness of the implementation intervention in reducing imaging for LBP, before large-scale implementation can be considered.

Imaging for low back pain: is clinical use consistent with guidelines? A systematic review and meta-analysis.

BACKGROUND CONTEXT: The problem of imaging patients with low back pain (LBP) when it is not indicated is well recognized. The converse is also possible, although rarely considered. The extent of these two problems is presently unclear. PURPOSE: This study aimed to estimate how commonly overuse, and also underuse, of imaging occurs in the management of LBP, and how appropriate use of imaging is assessed. DESIGN: This is a systematic review and meta-analysis. PATIENT SAMPLE: The sample comprised patients with LBP presenting to primary care. OUTCOME MEASURES: Proportions of inappropriate referral, and inappropriate non-referral, for diagnostic imaging for LBP were the outcome measures. METHODS: MEDLINE, EMBASE, and CINAHL were searched from January 1, 1995 to December 17, 2017. Two authors independently assessed study quality and extracted data. Meta-analyses were performed where appropriate, and strength of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluation system. RESULTS: Thirty-three studies were included. In patients referred for lumbar imaging, 34.8% (95% confidence interval [CI]: 27.1, 43.3) were judged inappropriate by the absence of red flags for serious pathology and 31.6% (95% CI: 28.3, 35.1) were judged inappropriate by the criteria of no clinical suspicion of pathology. In patients presenting for care, imaging was inappropriately performed in 27.7% of cases (95% CI: 21.3, 35.1) when judged by duration of episode, 9.0% of cases (95% CI: 7.4, 11.0) when judged by absence of red flags, and 7.0% (95% CI: 1.8, 23.3) when judged by no clinical suspicion of pathology. In patients presenting for care, imaging was not performed where appropriately indicated in 65.6% (95% CI: 51.8, 77.2) of patients who presented with red flags, and 60.8% (95% CI: 42.0, 76.8) with clinical suspicion of serious pathology. CONCLUSIONS: Inappropriate imaging is common in LBP management, including both overuse in those where imaging is not indicated and underuse of imaging when it is indicated. Appreciating that both underuse and overuse can occur is fundamental to efforts to improve imaging practice to align with current guidelines and best evidence.

Cerebellar and hindbrain motion in Chiari malformation with and without syringomyelia.

OBJECTIVE: The pathogenesis of syringomyelia associated with Chiari malformation type I (CM-I) is unclear. Theories of pathogenesis suggest the cerebellar tonsils may obstruct CSF flow or alter pressure gradients, or their motion might act as a piston to increase CSF pressure in the spinal subarachnoid space. This study was performed to measure cerebellar tonsillar and hindbrain motion in CM-I and assess the potential contributions to syrinx formation. METHODS: Sixty-four CM-I patients and 25 controls were retrospectively selected from a clinical database, and all subjects had undergone cardiac-gated cine balanced fast-field echo MRI. There were a total of 36 preoperative CM-I scans, which consisted of 15 patients with and 21 patients without syringomyelia. Nineteen patients underwent paired pre- and postoperative imaging. Anteroposterior (AP) and superoinferior (SI) movements of the tip of the cerebellar tonsils, obex, fastigium of the fourth ventricle, pontomedullary junction, and cervicomedullary junction were measured. The distance between the fastigium and tip of the tonsils was used to calculate tonsillar tissue strain (Δi/i0). RESULTS: CM-I patients had significantly greater cerebellar tonsillar motion in both the AP and SI directions than controls (AP +0.34 mm [+136%], p < 0.001; SI +0.49 mm [+163%], p < 0.001). This motion decreased after posterior fossa decompression (AP -0.20 mm [-33%], p = 0.001; SI -0.29 mm [-36%]; p < 0.001), but remained elevated above control levels (AP +56%, p = 0.021; SI +67%, p = 0.015). Similar trends were seen for all other tracked landmarks. There were no significant differences in the magnitude or timing of motion throughout the hindbrain between CM-I patients with and without syringomyelia. Increased tonsillar tissue strain correlated with Valsalva headaches (p = 0.03). CONCLUSIONS: Cerebellar tonsillar motion may be a potential marker of CM-I and may have use in tailoring surgical procedures. The lack of association with syringomyelia suggests that tonsillar motion alone is not the driver of syrinx formation. Tonsillar tissue strain may play a part in the pathophysiology of Valsalva headaches.

Liposuction for Advanced Lymphedema: A Multidisciplinary Approach for Complete Reduction of Arm and Leg Swelling.

PURPOSE: This research describes and evaluates a liposuction surgery and multidisciplinary rehabilitation approach for advanced lymphedema of the upper and lower extremities. METHODS: A prospective clinical study was conducted at an Advanced Lymphedema Assessment Clinic (ALAC) comprised of specialists in plastic surgery, rehabilitation, imaging, oncology, and allied health, at Macquarie University, Australia. Between May 2012 and 31 May 2014, a total of 104 patients attended the ALAC. Eligibility criteria for liposuction included (i) unilateral, non-pitting, International Society of Lymphology stage II/III lymphedema; (ii) limb volume difference greater than 25 %; and (iii) previously ineffective conservative therapies. Of 55 eligible patients, 21 underwent liposuction (15 arm, 6 leg) and had at least 3 months postsurgical follow-up (85.7 % cancer-related lymphedema). Liposuction was performed under general anesthesia using a published technique, and compression garments were applied intraoperatively and advised to be worn continuously thereafter. Limb volume differences, bioimpedance spectroscopy (L-Dex), and symptom and functional measurements (using the Patient-Specific Functional Scale) were taken presurgery and 4 weeks postsurgery, and then at 3, 6, 9, and 12 months postsurgery. RESULTS: Mean presurgical limb volume difference was 45.1 % (arm 44.2 %; leg 47.3 %). This difference reduced to 3.8 % (arm 3.6 %; leg 4.3 %) by 6 months postsurgery, a mean percentage volume reduction of 89.6 % (arm 90.2 %; leg 88.2 %) [p < 0.001]. All patients had improved symptoms and function. Bioimpedance spectroscopy showed reduced but ongoing extracellular fluid, consistent with the underlying lymphatic pathology. CONCLUSIONS: Liposuction is a safe and effective option for carefully selected patients with advanced lymphedema. Assessment, treatment, and follow-up by a multidisciplinary team is essential.

Risk factors for a recurrence of low back pain.

BACKGROUND CONTEXT: The clinical importance of lumbar pathology identified on magnetic resonance imaging (MRI) remains unclear. It is plausible that pathology seen on MRI is a risk factor for a recurrence of low back pain (LBP); however, to our knowledge, this has not been investigated by previous studies. PURPOSE: The aim was to investigate whether lumbar pathology, identifiable on MRI, increases the risk of a recurrence of LBP. STUDY DESIGN: This was a prospective inception cohort study with 1-year follow-up. PATIENT SAMPLE: Seventy-six people who had recovered from an episode of LBP within the previous 3 months were included. OUTCOME MEASURES: The primary outcome was time to recurrence of LBP, which was determined by contacting participants at 2-month intervals for 12 months. METHODS: All participants underwent a baseline assessment including MRI scan and completion of a questionnaire, which assessed a range of potential risk factors for recurrence. Magnetic resonance imaging scans were reported for the presence of a range of MRI findings. The primary analysis investigated the predictive value of two clinical features (age and number of previous episodes) and six MRI findings (disc degeneration, high intensity zone, Modic changes, disc herniation, facet joint arthrosis, and spondylolisthesis) in a multivariate Cox regression model. We decided a priori that dichotomous predictors with hazard ratios (HRs) of greater than 1.5 or less than 0.67 would be considered potentially clinically important and justify further investigation. RESULTS: Of the eight predictors entered into the primary multivariate model, three (disc degeneration, high intensity zone, and number of previous episodes) met our a priori threshold for potential importance. Participants with disc degeneration score greater than or equal to 3 (Pfirrmann scale) had a HR of 1.89 (95% confidence interval [CI] 0.42-8.53) compared with those without. Patients with high intensity zone had an HR of 1.84 (95% CI 0.94-3.59) compared with those without. For every additional previous episode, participants had an HR of 1.04 (95% CI 1.02-1.07). CONCLUSIONS: We identified promising risk factors for a recurrence of LBP, which should be further investigated in larger trials. The findings suggest that pathology seen on MRI plays a potentially important role in recurrence of LBP.

Effectiveness of interventions designed to reduce the use of imaging for low-back pain: a systematic review.

BACKGROUND: Rates of imaging for low-back pain are high and are associated with increased health care costs and radiation exposure as well as potentially poorer patient outcomes. We conducted a systematic review to investigate the effectiveness of interventions aimed at reducing the use of imaging for low-back pain. METHODS: We searched MEDLINE, Embase, CINAHL and the Cochrane Central Register of Controlled Trials from the earliest records to June 23, 2014. We included randomized controlled trials, controlled clinical trials and interrupted time series studies that assessed interventions designed to reduce the use of imaging in any clinical setting, including primary, emergency and specialist care. Two independent reviewers extracted data and assessed risk of bias. We used raw data on imaging rates to calculate summary statistics. Study heterogeneity prevented meta-analysis. RESULTS: A total of 8500 records were identified through the literature search. Of the 54 potentially eligible studies reviewed in full, 7 were included in our review. Clinical decision support involving a modified referral form in a hospital setting reduced imaging by 36.8% (95% confidence interval [CI] 33.2% to 40.5%). Targeted reminders to primary care physicians of appropriate indications for imaging reduced referrals for imaging by 22.5% (95% CI 8.4% to 36.8%). Interventions that used practitioner audits and feedback, practitioner education or guideline dissemination did not significantly reduce imaging rates. Lack of power within some of the included studies resulted in lack of statistical significance despite potentially clinically important effects. INTERPRETATION: Clinical decision support in a hospital setting and targeted reminders to primary care doctors were effective interventions in reducing the use of imaging for low-back pain. These are potentially low-cost interventions that would substantially decrease medical expenditures associated with the management of low-back pain.

Augmented active surface model for the recovery of small structures in CT.

This paper devises an augmented active surface model for the recovery of small structures in a low resolution and high noise setting, where the role of regularization is especially important. The emphasis here is on evaluating performance using real clinical computed tomography (CT) data with comparisons made to an objective ground truth acquired using micro-CT. In this paper, we show that the application of conventional active contour methods to small objects leads to non-optimal results because of the inherent properties of the energy terms and their interactions with one another. We show that the blind use of a gradient magnitude based energy performs poorly at these object scales and that the point spread function (PSF) is a critical factor that needs to be accounted for. We propose a new model that augments the external energy with prior knowledge by incorporating the PSF and the assumption of reasonably constant underlying CT numbers.

Augmented ocular vestibular evoked myogenic potentials to air-conducted sound in large vestibular aqueduct syndrome.

OBJECTIVE: To demonstrate the value of recording air-conducted ocular Vestibular Evoked Myogenic Potentials (oVEMP) in a patient with bilaterally enlarged vestibular aqueducts. DESIGN: Cervical VEMP and oVEMP were recorded from a patient presenting with bilateral hearing loss and imbalance, attributable to large vestibular aqueduct syndrome. The stimuli were air-conducted tone bursts at octave frequencies from 250 to 2000 Hz. Amplitudes and thresholds were measured and compared with the normal response range of 32 healthy control subjects. RESULTS: oVEMP reflexes demonstrated pathologically increased amplitudes and reduced thresholds for low-frequency tone bursts. Cervical VEMP amplitudes and thresholds were within normal limits for both ears across all frequencies of stimulation. CONCLUSIONS: This study is the first to describe the augmentation of AC oVEMPs in an adult with large vestibular aqueduct syndrome.

Effect of weight loss on upper airway size and facial fat in men with obstructive sleep apnoea.

BACKGROUND: Obstructive sleep apnoea (OSA) is commonly associated with obesity and can be improved by weight loss. Changes in upper airway size related to regional fat loss may mediate the improvement in OSA. This study aimed to assess changes in upper airway size and regional facial and abdominal fat with weight loss and their association with OSA improvement. METHODS: Middle-aged obese men with moderate-to-severe OSA underwent a 24-week sibutramine-assisted weight loss trial. Polysomnography and CT of the head and neck were performed at baseline and 24 weeks. The upper airway lumen and facial and parapharyngeal fat were measured with image analysis software. RESULTS: Post-intervention there was a significant reduction in weight (-7.8±4.2 kg, p<0.001) and apnoea-hypopnoea index (AHI) (-15.9±20.5 events/h, p<0.001). Velopharyngeal airway volume significantly increased from baseline (5.3±0.4 to 6.3±0.3 cm(3), p<0.01) and facial and paraphayngeal fat volume significantly reduced. A reduction in upper airway length was associated with improvement in AHI (r=0.385, p=0.005). The variance in AHI improvement was best explained by changes in upper airway length and visceral abdominal fat (R(2)=0.31, p=0.004). CONCLUSIONS: Weight loss increases velopharyngeal airway volume, but changes in upper airway length appear to have a greater influence on the reduction in apnoea frequency. Inter-individual variability in the effects of weight loss on OSA severity cannot be explained in terms of changes in upper airway structure and local fat deposition alone.

A mathematical model of human semicircular canal geometry: a new basis for interpreting vestibular physiology.

We report a precise, simple, and accessible method of mathematically measuring and modeling the three-dimensional (3D) geometry of semicircular canals (SCCs) in living humans. Knowledge of this geometry helps understand the development and physiology of SCC stimulation. We developed a framework of robust techniques that automatically and accurately reconstruct SCC geometry from computed tomography (CT) images and are directly validated using micro-CT as ground truth. This framework measures the 3D centroid paths of the bony SCCs allowing direct comparison and analysis between ears within and between subjects. An average set of SCC morphology is calculated from 34 human ears, within which other geometrical attributes such as nonplanarity, radius of curvature, and inter-SCC angle are examined, with a focus on physiological implications. These measurements have also been used to critically evaluate plane fitting techniques that reconcile many of the discrepancies in current SCC plane studies. Finally, we mathematically model SCC geometry using Fourier series equations. This work has the potential to reinterpret physiology and pathophysiology in terms of real individual 3D morphology.

Changes in regional adiposity and cardio-metabolic function following a weight loss program with sibutramine in obese men with obstructive sleep apnea.

BACKGROUND: Although obstructive sleep apnea (OSA) is strongly linked with obesity, both conditions have been associated with increased cardiovascular risk including glucose intolerance, dyslipidemia, and hypertension independent of one another. Weight loss is known to improve both cardiovascular risk and OSA severity. The aim of this study was to evaluate cardiovascular and metabolic changes, including compartment-specific fat loss in obese OSA subjects undergoing a weight loss program. DESIGN: Observational study. PARTICIPANTS: 93 men with moderate-severe OSA. INTERVENTIONS: 6-month open-label weight loss trial combining sibutramine (a serotonin and noradrenaline reuptake inhibitor) with a 600-kcal deficit diet and exercise. MEASUREMENTS AND RESULTS: At baseline and following 6 months of weight loss, OSA was assessed together with CT-quantified intraabdominal and liver fat and markers of metabolic and cardiovascular function. At 6 months, weight loss and improvements in OSA were accompanied by improved insulin resistance (HOMA), increased HDL cholesterol, and reduced total cholesterol/HDL ratio. There were also reductions in measures of visceral and subcutaneous abdominal fat and liver fat. Reductions in liver fat and sleep time spent below 90% oxyhemoglobin saturation partly explained the improvement in HOMA (R2 = 0.18). In contrast, arterial stiffness (aortic augmentation index), heart rate, blood pressure, and total cholesterol did not change. CONCLUSIONS: Weight loss with sibutramine was associated with improvements in metabolic and body composition risk factors but not blood pressure or arterial stiffness. Improved insulin resistance was partly associated with reductions in liver fat and hypoxemia associated with sleep apnea.