Motion In-Betweening via Deep ∆-Interpolator.

We show that the task of synthesizing human motion conditioned on a set of key frames can be solved more accurately and effectively if a deep learning based interpolator operates in the delta mode using the spherical linear interpolator as a baseline. We empirically demonstrate the strength of our approach on publicly available datasets achieving state-of-the-art performance. We further generalize these results by showing that the ∆-regime is viable with respect to the reference of the last known frame (also known as the zero-velocity model). This supports the more general conclusion that operating in the reference frame local to input frames is more accurate and robust than in the global (world) reference frame advocated in previous work. Our code is publicly available at: https://github.com/boreshkinai/delta-interpolator.

Is MRI screening for bone marrow oedema useful in predicting lumbar bone stress injuries in adult male professional cricketers? A New Zealand pilot study.

OBJECTIVES: The aims were to (1) prospectively observe the incidence of bone marrow oedema in asymptomatic adult male domestic professional cricketers during a season and evaluate its relationship to the development of lumbar bone stress injury and (2) further understand the practicalities of implementing a Magnetic Resonance Imaging-based screening program to prevent lumbar bone stress injury in New Zealand cricket. DESIGN: Prospective observational cohort. METHODS: Adult male pace bowlers received 6-weekly pre-planned Magnetic Resonance Imaging scans over a single season to determine the presence and intensity of bone marrow oedema in the posterior vertebral arches of the lumbar spine. The participants bowling volume and back pain levels were monitored prospectively. RESULTS: 22 participants (mean age 25.3 years (range 20-32 years)) completed all 4 scans. Ten participants had a prior history of lumbar bone stress injury. Ten participants (45 %, 95 % confidence interval 24-68 %) had bone marrow oedema evident on at least one scan, with 9 (41 %) participants recording a bone marrow oedema intensity ≥ 2 and 5 (23 %) participants demonstrated an intensity ≥ 3. During the study one participant was diagnosed with a lumbar bone stress reaction. No participants developed a lumbar bone stress fracture. CONCLUSIONS: Due to the lower incidence of lumbar bone stress injuries in adult bowlers coupled with uncertainty over appropriate threshold values for bone marrow oedema intensity, implementation of a resource intense screening program aimed at identifying adult domestic cricketers at risk of developing a lumbar bone stress injury is not currently supported.

Pinpoint accuracy: guided core biopsy diagnostic accuracy in musculoskeletal lesions.

BACKGROUND: Core biopsy is integral in the work-up of diagnosis for musculoskeletal lesions. Prior to referral through Christchurch hospital-a tertiary referral centre for sarcomas/musculoskeletal lesions, many patients undertake guided core biopsy in peripheral hospitals. We wished to assess the accuracy of these biopsies undertaken in the peripheral centres and compare to those done in the tertiary setting. METHODS: A retrospective analysis of image-guided core biopsies done in the South Island of New Zealand over a 5 year period was performed. An electronic database enquiry was made, and electronic notes were then screened for core biopsy results including subsequent biopsies done of the same lesion. Results from guided core biopsy were then recorded as diagnostic if the pathologist was able to reach or a definitive diagnosis, or guide management sufficiently. RESULTS: 223 patients with 229 biopsies were analysed. Overall accuracy of core biopsies were 83% across all centres. There were similar results between CT and ultrasound as well as soft tissue and bone lesions. Between the regions, the peripheral centres showed high accuracy compared with the tertiary centres. CONCLUSION: The regional centres demonstrated high diagnostic yield, and the current practice of providing core biopsy locally where possible prior to referral to a tertiary sarcoma, remains valid.

DECT-CLUST: Dual-Energy CT Image Clustering and Application to Head and Neck Squamous Cell Carcinoma Segmentation.

Dual-energy computed tomography (DECT) is an advanced CT computed tomography scanning technique enabling material characterization not possible with conventional CT scans. It allows the reconstruction of energy decay curves at each 3D image voxel, representing varied image attenuation at different effective scanning energy levels. In this paper, we develop novel unsupervised learning techniques based on mixture models and functional data analysis models to the clustering of DECT images. We design functional mixture models that integrate spatial image context in mixture weights, with mixture component densities being constructed upon the DECT energy decay curves as functional observations. We develop dedicated expectation-maximization algorithms for the maximum likelihood estimation of the model parameters. To our knowledge, this is the first article to develop statistical functional data analysis and model-based clustering techniques to take advantage of the full spectral information provided by DECT. We evaluate the application of DECT to head and neck squamous cell carcinoma. Current image-based evaluation of these tumors in clinical practice is largely qualitative, based on a visual assessment of tumor anatomic extent and basic one- or two-dimensional tumor size measurements. We evaluate our methods on 91 head and neck cancer DECT scans and compare our unsupervised clustering results to tumor contours traced manually by radiologists, as well as to several baseline algorithms. Given the inter-rater variability even among experts at delineating head and neck tumors, and given the potential importance of tissue reactions surrounding the tumor itself, our proposed methodology has the potential to add value in downstream machine learning applications for clinical outcome prediction based on DECT data in head and neck cancer.

A prospective study of shoulder pain in primary care: prevalence of imaged pathology and response to guided diagnostic blocks.

BACKGROUND: The prevalence of imaged pathology in primary care has received little attention and the relevance of identified pathology to symptoms remains unclear. This paper reports the prevalence of imaged pathology and the association between pathology and response to diagnostic blocks into the subacromial bursa (SAB), acromioclavicular joint (ACJ) and glenohumeral joint (GHJ). METHODS: Consecutive patients with shoulder pain recruited from primary care underwent standardised x-ray, diagnostic ultrasound scan and diagnostic injections of local anaesthetic into the SAB and ACJ. Subjects who reported less than 80% reduction in pain following either of these injections were referred for a magnetic resonance arthrogram (MRA) and GHJ diagnostic block. Differences in proportions of positive and negative imaging findings in the anaesthetic response groups were assessed using Fishers test and odds ratios were calculated a for positive anaesthetic response (PAR) to diagnostic blocks. RESULTS: In the 208 subjects recruited, the rotator cuff and SAB displayed the highest prevalence of pathology on both ultrasound (50% and 31% respectively) and MRA (65% and 76% respectively). The prevalence of PAR following SAB injection was 34% and ACJ injection 14%. Of the 59% reporting a negative anaesthetic response (NAR) for both of these injections, 16% demonstrated a PAR to GHJ injection. A full thickness tear of supraspinatus on ultrasound was associated with PAR to SAB injection (OR 5.02; p < 0.05). Ultrasound evidence of a biceps tendon sheath effusion (OR 8.0; p < 0.01) and an intact rotator cuff (OR 1.3; p < 0.05) were associated with PAR to GHJ injection. No imaging findings were strongly associated with PAR to ACJ injection (p ≤ 0.05). CONCLUSIONS: Rotator cuff and SAB pathology were the most common findings on ultrasound and MRA. Evidence of a full thickness supraspinatus tear was associated with symptoms arising from the subacromial region, and a biceps tendon sheath effusion and an intact rotator cuff were associated with an intra-articular GHJ pain source. When combined with clinical information, these results may help guide diagnostic decision making in primary care.

Microwave Radar for Breast Screening: Initial Clinical Data with Suspicious-Lesion Patients.

We present results of a statistical analysis of patient measurements with a time-domain multistatic microwave radar for early breast cancer detection. The scanned patients varied in age, but all showed a suspicious lesion on a previous breast screening with a mammogram or MRI. We assess the correlation between the signal response of preprocessed data and specific patient attributes. The goal is to use the results towards optimizing the clinical prototype, in order to improve the overall signal quality for a future large-scale study.

The use of an Ossis custom 3D-printed tri-flanged acetabular implant for major bone loss: minimum 2-year follow-up.

INTRODUCTION: Custom 3D-printed acetabular implants are a new technology used in hip surgery with ever-increasing frequency. They offer patient-specific implants to optimise filling of bone defects and implant-bone contact, without the need for excessive bone resection. METHODS: This is a retrospective cohort study of 46 consecutive patients who underwent an Ossis unilateral custom 3D-printed acetabular implant. Clinical (Oxford Hip Score OHS-60), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Harris Hip Score (HHS) and radiological (restoration of biomechanical hip centre, osteointegration, wear, heterotrophic ossification) results were assessed. RESULTS: Patient mean age was 68 years and follow-up was 38 months (minimum 24 months). 10 patients were excluded from the outcome analysis; 2 patients died, 1 required revision for deep infection and 7 were lost to follow-up. Of the 36 patients included, 21 had severe osteolysis. 7 were revised for infection, 3 for tumoural defects, 3 for metallosis, 1 for dysplasia and 1 for trauma (Paprosky 2a [n=6], 2b [n=2], 2c [n=5], 3a [n=6], 3b [n=11], pelvic dissociation [n=6]). OHS significantly improved postoperatively (16-8-48.4 p=0.027). Postoperative functional scores were good (WOMAC 98; HHS 79). The biomechanical hip centre was restored in all patients. 1 patient had early implant migration with subsequent stabilisation. 2 patients had radiographs concerning for failure of osteointegration. 1 patient had recurrent dislocations. CONCLUSIONS: The mid-term results of the Ossis custom 3D-printed tri-flanged acetabular implant for the management of severe acetabular defects are encouraging. The improvement in functional scores and radiographic outcomes are comparable to similar designs. In addition, no cases have required revision for aseptic loosening.

An Early Clinical Study of Time-Domain Microwave Radar for Breast Health Monitoring.

This study reports on monthly scans of healthy patient volunteers with the clinical prototype of a microwave imaging system. The system uses time-domain measurements, and incorporates a multistatic radar approach to imaging. It operates in the 2-4 GHz range and contains 16 wideband sensors embedded in a hemispherical dielectric radome. The system has been previously tested on tissue phantoms in controlled experiments. With this system prototype, we scanned 13 patients (26 breasts) over an eight-month period, collecting a total of 342 breast scans. The goal of the study described in this paper was to investigate how the system measurements are impacted by multiple factors that are unavoidable in monthly monitoring of human subjects. These factors include both biological variability (e.g., tissue variations due to hormonal changes or weight gain) and measurement variability (e.g., inconsistencies in patient positioning, system noise). For each patient breast, we process the results of the monthly scans to assess the variability in both the raw measured signals and in the generated images. The significance of this study is that it quantifies how much variability should be anticipated when conducting microwave breast imaging of a healthy patient over a longer period. This is an important step toward establishing the feasibility of the microwave radar imaging system for frequent monitoring of breast health.

MRI Inner Ear Imaging and Tone Burst Electrocochleography in the Diagnosis of Ménière's Disease.

OBJECTIVE: To compare the sensitivity of gadolinium MRI inner imaging with tone burst electrocochleography (EcochG) for diagnosing endolymphatic hydrops. STUDY DESIGN: A prospective study on patients who were to have an MRI scan to exclude retrocochlear pathology. SETTING: Tertiary care center. PATIENTS: One hundred and two patients: 57 patients with Possible, Probable, or Definite Ménière's Disease, 25 with asymmetrical hearing loss, 18 with sudden sensorineural hearing loss, and 2 with unilateral tinnitus had additional MRI inner ear imaging and click and tone burst stimulus EcochG testing. INTERVENTION: Diagnostic. MAIN OUTCOME MEASURE: To compare the sensitivity of the two techniques. RESULTS: In 30 patients with symptom-based Definite Ménière's Disease, tone burst EcochG was positive in 25 (83%) and the click EcochG was positive in 9/30 (30%), and gadolinium MRI imaging diagnosed hydrops in 14 (47%). A positive result for either MRI imaging or tone burst EcochG was seen in 26 patients (87%). In 14 subjects with symptom-based Probable Ménière's Disease, 10 (71%) had either a positive EcochG or MRI. In 13 with Possible Ménière's Disease, four (31%) had a positive EcochG or MRI. CONCLUSION: This study confirms the greatly enhanced diagnostic sensitivity of tone burst EcochG over click response in diagnosing endolymphatic hydrops in Ménière's disease. Even though adequate MRI imaging was achieved in 90%, tone burst EcochG was a more sensitive test.

Time-domain microwave breast cancer detection: extensive system testing with phantoms.

Early detection of breast cancer is known to be a key factor in the successful treatment of the disease. Here, we present a detection technique complementary to the currently used modalities (primarily mammography, ultrasound and magnetic resonance imaging). Our time-domain breast cancer detection system transmits microwave-range pulses into the breast and records the scattering off of the breast in order to detect malignancies. This method is made possible by an intrinsic contrast in the dielectric parameters, specifically the relative permittivity and conductivity, of the healthy and malignant breast tissues over the microwave frequency range. The long-term goal of our work is to develop a system that can be used periodically to monitor for unusual changes in breast tissues; for instance, healthy breasts would be scanned, and follow-up scans at regular intervals would detect any small changes in breast tissue composition that could indicate the presence of a malignant growth. At that point, the patient would be referred to see a doctor for further investigation of the abnormal results. Such a system would compare each new scan with previous ones to determine the level of tissue changes, and would be used by patients at home. We report feasibility and performance tests for our initial system, conducted with breast phantoms made up of tissue-mimicking materials (unique skin, fat, gland and tumor mixtures). We initiated the system testing with simple homogeneous phantoms, consisting solely of adipose tissue. Then, we extended our tests to cases of increasing complexity by adding a skin layer and varying percentages of glandular structures and tumor sizes. In order to optimize the experimental system, we performed tests with multiple antenna arrangements, tumor sizes and locations. This work shows that there are specific antenna arrangements that are advantageous for tumor detection and demonstrates the capabilities of our time-domain microwave breast tumor detection system.

Microwave radar and microwave-induced thermoacoustics: dual-modality approach for breast cancer detection.

Microwave radar and microwave-induced thermoacoustics, recently proposed as promising breast cancer detection techniques, each have shortcomings that reduce detection performance. Making the assumption that the measurement noises experienced when applying these two techniques are independent, we propose a methodology to process the input signals jointly based on a hypothesis testing framework. We present two test statistics and derive their distributions to set the thresholds. The methodology is evaluated on numerically simulated signals acquired from 2-D numerical breast models using finite-difference time-domain method. Our results show that the proposed dual-modality approach can give a significant improvement in detection performance.

Atypical subtrochanteric fractures, bisphosphonates, blinded radiological review.

BACKGROUND: Recent reports have suggested that a certain type of subtrochanteric and diaphyseal femoral fractures maybe associated with bisphosphonate (BP) therapy. We assessed the association between BP use in atypical and typical femoral fractures in a retrospective study and also looked at the rate of coding errors. METHODS: All cases between July 2003 and June 2008 with International Classification of Disease, 10th revision discharge codes for femoral fractures (S72.2 subtrochanteric and S72.3 fracture of shaft of femur) were reviewed. Cases were excluded if there was significant trauma, underlying bone disease or coding error. The remaining cases' films were assessed by an independent, blinded, single radiologist to assess for atypical features (thickened cortices, transverse fractures, medial cortical spike) with additional exclusion criteria of periprosthetic fractures and bone pathology. Odds ratios were calculated comparing BP use in atypical and typical fractures. RESULTS: Six atypical fractures were found in the study period. Compared with the 65 typical fractures, there was an association between BP use and atypical fractures (odds ratio 5.5) but it did not reach statistical significance (0.97-31). Atypical femoral fractures accounted for <0.1% of total fracture admissions during this period. There was a 20% rate of miscoding. CONCLUSION: This study shows a nonsignificant trend towards alendronate/BP use and atypical femoral fractures compared with typical femoral fractures. These fractures were rare <0.1% and the benefit and treatment of osteoporosis with BPs currently seems likely to outweigh the perceived risks. Individual case and radiology review is important as coding errors were frequent.

Event-related potential measures of processing during an Implicit Association Test.

This study recorded event-related potentials during the Implicit Association Test, a reaction time-based measure of implicit social attitudes. An N2, peaking at about 350 ms was larger in the incongruent condition, perhaps reflecting greater response monitoring. The latency to an initial late positive peak, P300, a measure of stimulus classification time, was not longer in the incongruent than the congruent condition. A later small amplitude positive peak was observed in the incongruent condition, but was not visible in the congruent condition. The additional positivity is consistent with the hypothesis that participants make an initial decision to determine whether a task set switch is required, and then make a subsequent decision about the correct response, perhaps resulting in delayed reaction times.

Computed tomography assessment of hip joints in asymptomatic individuals in relation to femoroacetabular impingement.

BACKGROUND: Femoroacetabular impingement has become a well-recognized entity predisposing to acetabular labral tears and chondral damage, and subsequently development of osteoarthritis of the hip joint. In the authors' experience, it is common to see bony abnormalities predisposing to femoroacetabular impingement in the contralateral asymptomatic hips in patients with unilateral femoroacetabular impingement. PURPOSE: This study was undertaken to investigate the prevalence of bony abnormalities predisposing to femoroacetabular impingement in asymptomatic individuals without exposing study participants to unnecessary radiation. STUDY DESIGN: Cross-sectional study; Level of evidence, 4. METHODS: Fifty individuals (100 hip joints), ranging from 15 to 40 years of age, who were seen at a local hospital between March and August 2008 with abdominal trauma or nonspecific abdominal pain in whom abdominal computed tomography was performed to aid diagnosis were prospectively studied. These patients were not known to have any history of hip-related problems. Raw data from the abdominal computed tomography scan, performed on a 64-slice multidetector computed tomography scanner, were reformatted using bone algorithm into several different planes. Several measurements and observations of the hip joints were made in relation to femoroacetabular impingement. RESULTS: The 100 hip joints from 50 patients with no history of hip problems demonstrated that 39% of the joints (31% of female, 48% of male joints) have at least 1 morphologic aspect predisposing to femoroacetabular impingement. The majority (66% to 100% ) of the findings were bilateral; 33% of female and 52% of male asymptomatic participants in our study had at least 1 predisposing factor for femoroacetabular impingement in 1 or both of their hip joints. Based on the data collected from this study, the acetabular crossover sign had a 71% sensitivity and 88% specificity for detecting acetabular retroversion. Nonquantitative assessment of the femoral head at the anterior, anterolateral, and lateral head/neck junctions demonstrated that 74% of the joints had an aspherical femoral head. CONCLUSION: The study demonstrated substantial prevalence of bony characteristics predisposing to femoroacetabular impingement in asymptomatic individuals according to the established measurement parameters in current literature.

Cost analysis of traditional follow-up protocol versus MRI for radiographically occult scaphoid fractures: a pilot study for the Accident Compensation Corporation.

AIMS: Assessment of the cost-effectiveness of early magnetic resonance imaging (MRI) for suspected radiographically occult scaphoid fractures. Methods Compare costs of patients presenting acutely with suspected scaphoid injuries (managed either with traditional follow-up radiographs and plasters) versus early MRI to exclude a fracture. Results The average medical cost for the control group was NZ470 dollars versus NZ533 dollars in the MRI group. The cost to exclude a fracture was NZ437 dollars with MRI versus NZ459 dollars for the traditional protocol. Weekly compensation costs were comparable. Conclusions The early diagnosis of clinical scaphoid fractures has clear clinical advantages. The use of MRI in this situation is cost-effective, and we recommend that it be offered as part of the routine investigative work-up available for this difficult, but common, clinical scenario.

Frontal recess air cells: spectrum of CT appearances.

The CT appearances of frontal recess air cells is reviewed.