Quantitative imaging techniques for the assessment of osteoporosis and sarcopenia

Bone and muscle are two deeply interconnected organs and a strong relationship between them exists in their development and maintenance. The peak of both bone and muscle mass is achieved in early adulthood, followed by a progressive decline after the age of 40. The increase in life expectancy in developed countries resulted in an increase of degenerative diseases affecting the musculoskeletal system. Osteoporosis and sarcopenia represent a major cause of morbidity and mortality in the elderly population and are associated with a significant increase in healthcare costs. Several imaging techniques are currently available for the non-invasive investigation of bone and muscle mass and quality. Conventional radiology, dual energy X-ray absorptiometry (DXA), computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound often play a complementary role in the study of osteoporosis and sarcopenia, depicting different aspects of the same pathology. This paper presents the different imaging modalities currently used for the investigation of bone and muscle mass and quality in osteoporosis and sarcopenia with special emphasis on the clinical applications and limitations of each technique and with the intent to provide interesting insights into recent advances in the field of conventional imaging, novel high-resolution techniques and fracture risk

Development and assessment of Computer Aided Detection (CAD) software for assisting diagnosis in cervical spine projection radiography

Introduction Cervical spine injuries are a major burden on hospital services and have serious consequences for morbidity and mortality; this also affects society due to the associated high care and medical costs. These injuries have the potential to be missed or misdiagnosed, although it must be stated that this phenomena is not unique to cervical spine injuries, and has been seen throughout most imaging services. One possible method to counter this is the use of computer aided detection (CAD) software integrated into the imaging process. This can help increase sensitivity and specificity scores (and thus area under a curve (AUC) scores) by indicating any injuries/pathologies using a pattern recognition algorithm. Methods Lateral cervical spine images were collected from clinical cases and anonymysed by the hospital. These were segmented using a Matlab script to develop ground truth images for the computer scientists to develop cervical spine CAD (CSPINE-CAD) software using machine learning algorithms. The CSPINE CAD software was then assessed in a number of studies as described below. Participants were a convenience sample recruited at the University of Exeter and the Royal Devon and Exeter hospital, and were involved in three tests. These tests all investigated the AUC differences when making a diagnosis without, and with the CSPINE-CAD software. These three tests were: The first test involving five third year radiography students each diagnosing the same five lateral C-spine radiographs, first without and then with the use of the CSPINE-CAD software. Answers were provided by the students via a comments box in which they would make an original diagnosis, then apply the CAD software and then make a re-diagnosis. Upon completion a questionnaire was filled in about their opinions, feedback and confidence whilst using the software. The second test involved 11 third year radiography students from the same cohort each diagnosing 30 lateral C-spine radiographs. This involved using a representation of the CSPINE-CAD software, and followed the same method of diagnosis (a comments box) as in the first test, concluding with a questionnaire. The third test involved 26 participants made up of junior doctors and qualified radiographers, each diagnosing 30 radiographs without and with CSPINE-CAD. This third test did not utilise a comments box, but instead used an answer sheet which contained blank boxes representing each vertebral body and each vertebral junction. These boxes were filled in by the participant using a number between one and six (one representing no injury, and six being 80-100% confident there is an injury). These boxes would all be filled for each image twice; once without CAD and once with CAD. The next image was loaded and the process repeated. Upon completion a questionnaire was again provided to allow the participants to give feedback and confidence about the software. Due to the ambiguity in the language used in the comments boxes of the first and second tests, it was concluded to analyse and produce two results per test. The first analysis was a benefit of the doubt analysis in which the diagnosis provided by the participants would receive some latitude (e.g. misalignment of C5 would be accepted if the “true” answer was misalignment C5/C6). The second analysis was more verbatim and received no latitude. All three tests were compared against the gold standard of a radiologists report, and calculated for AUC scores without and with CSPINE-CAD. Results None of the three test results were statistically significant. The first test showed an AUC increase of 1.39% (with latitude) and 9.54% (no latitude) when using CAD. The second test showed an AUC increase of 1.64% (with latitude) and a loss of 0.25% (no latitude) when using CAD. The third test showed that across all confidence values (2-6) the AUC is higher 1.65% without CAD. Additionally when reviewing only the highest confidence value (6) the AUC increases with CAD by 0.66%. Questionnaire data showed an increase in average confidence when using CAD across all three tests by 12%, 20% and 9.24% respectively, with the majority of participants agreeing that CAD was helpful as a second “pair of eyes” with scores of 100%, 100% and 73%. Conclusion Due to sample sizes and the amount of images being small a statistical significant result could not be reached. Although CSPINE-CAD has shown to be a possible method to reduce missed or misdiagnosed cervical spine injuries, further investigation and development is needed into this CAD software

'Clinical Triad' findings in Klippel-feil patients

E-Poster - Congenital Deformity: no. 530It has been propagated that Klippel-Feil Syndrome (KFS) is associated with the clinical triad findings (CTF) of short neck, low posterior hairline, and limited range of motion. This study noted that CTFs are not consistently noted in KFS patients. KFS patients with extensive congenitally fused cervical segments were more likely to exhibit one of the components of CTF.postprin

Radiostereometric analysis of initial femoral stem migration in cementless total hip arthroplasty of postmenopausal women : Exploring contributing factors in initial femoral stem migration

In cementless total hip arthroplasty (THA), femoral stems rely on the initial press‐fit fixation against the cortical bone to achieve osseointegration. In aging women, structural changes of the proximal femur may jeopardize the stem stability. Preoperative screening of bone quality and exploring the factors that cause stem migration may help in the selection process of patients for the use of cementless fixation techniques. Antiresorptive denosumab therapy might be efficient in preventing periprosthetic bone loss and reducing femoral stem migration in postmenopausal women. Sixty-five postmenopausal women with primary hip osteoarthritis (60 to 85 years old and Dorr A-type or B-type femur morphology) underwent cementless THA with implantation of a parallel-sided femoral component in a randomized double-blind placebo-controlled trial. The patients randomly received denosumab or a placebo 1 month before and 5 months after the surgery. The three-dimensional stem migration was measured using model-based radiostereometric analysis (RSA). Patient’s baseline characteristics, local and systemic bone mineral density (BMD) values measured by dual-energy X-ray absorptiometry (DXA), cortical-bone thicknes measured by pulse-echo ultrasonometry, surgery-related factors, and postoperative walking activity were examined for the association with stem migration. The accuracy and clinical precision of model-based RSA were comparable to those of marker-based RSA. Denosumab significantly decreased periprosthetic bone loss but did not reduce stem migration which occurred predominately during the first 3 months. DXA and pulse-echo ultrasonometry of the distal radius helped to identify patients at high risk of stem subsidence of more than 2 mm. Walking activity and local BMD dictated the direction and magnitude of stem rotation around y-axis. Femoral stem stability is sensitive to adequate bone stock. In postmenopausal women, stem migration is predominantly due to impaired bone quality. Inhibition of periprosthetic bone resorption did not prevent stem migration. Preoperative evaluation of the skeletal status is recommended for all postmenopausal women with hip osteoarthritis before scheduling cementless THA.Lonkan tekonivelen biologinen kiinnittyminen ikääntyvillä naisilla: varsiosan liikkeen radiostereometrinen analyysi Sementitön lonkan tekonivelleikkaus perustuu implantin biologiseen kiinnittymiseen. Kantavan varsiosan luutuminen edellyttää, että implantti saadaan leikkauksessa tukevasti paikoilleen kuoriluuta vasten. Tämän saavuttaminen voi olla vaikeaa naisilla, joille on kehittynyt vaihdevuosien jälkeen reisiluun kuoriluun ohentumista ja huokoistumista. Tästä johtuen on tärkeää selvittää ennen leikkausta potilaan luuston kunto. On myös arvioitava muita tekijöitä, jotka voivat lisätä varsiosan liikettä. Ennen leikkausta aloitettu luukatoa estävä lääkitys voi vahvistaa kuoriluuta ja näin parantaa varsiosan tukevuutta. Satunnaistettuun kliiniseen potilastutkimukseen osallistui 65 lonkan nivelrikkoa sairastavaa naispotilasta (keski-ikä 69 vuotta). Potilaille tehtiin sementitön lonkan tekonivelleikkaus. Ennen leikkausta aloitettiin luulääkitys (denosumabi), jonka tiedetään vahvistavan reisiluun kuoriluuta osteoporoosia sairastavilla naisilla. Potilaiden subjektiivista toipumista seurattiin kuvaavilla kyselykaavakkeilla ja myös objektiivisilla mittauksilla (kävelynopeus, kävelyaktiviteetti, luuntiheysmittaus, kuoriluun ultraäänimittaus ja luuaineenvaihdunnan merkkiaineet). Varsiosan kolmiulotteista liikettä seurattiin 3D-mallinnukseen perustuvalla radiostereometrisellä analyysillä. Menetelmän tarkkuus ja toistettavuus varmistettiin prekliinisessä kokeessa muoviluumalleilla. Lääkehoito esti reisiluun yläosan paikallisen luukadon varsiosan ympärillä, mutta se ei vähentänyt varsiosan painumista ja kiertymistä. Liikettä tapahtui ensimmäisten kuukausien aikana leikkauksesta. Varsiosat luutuivat ja hoitoryhmien välillä ei ollut eroa kliinisessä toipumisessa. Ennen leikkausta tehty ranteen kuoriluun paksuuden ultraäänimittaus (Bindex®) ja luuntiheysmittaus auttoivat tunnistamaan kohtalaisen hyvin ne potilaat, joille kehittyi varsiosan yli 2 mm painuminen leikkauksen jälkeen. Varsiosan kiertymisen suunta ja määrä heijastivat kävelyaktiivisuutta leikkauksen jälkeen. Tulokset vahvistivat aiempia tuloksia, että biologisesti kiinnittyvä lonkan tekonivelen varsiosa vaatii hyvää luuainesta. Luulääkkeellä (denosumabi) voidaan estää paikallista luukatoa, mutta luuresorption esto ei vähennä varsiosan alkuvaiheen liikettä. Luuston kunnon seulontaa suositellaan kaikille vaihevuosi-iän ohittaneille naisille, joille suunnitellaan sementitöntä lonkan tekonivelleikkausta

Selection of fusion levels in adolescent idiopathic scoliosis (AIS) using the fulcrum bending radiograph prediction: verification based on pedicle screw strategy

E-Poster - Adolescent Idiopathic Scoliosis: no. 297Utilizing the fulcrum bending radiographic technique to assess curve flexibility to aid in the selection of fusion levels, a prospective radiographic study was performed to assess the safety and effectiveness of pedicle screw fixation with alternate level screw strategy (ALSS) for thoracic AIS. This study suggests that ALSS obtains greater deformity correction than hook and hybrid systems, and improves balance without compromising fusion levels.postprin

The safety and efficacy of a remotely distractible, magnetic controlled growing rod (MCGR) for the treatment of scoliosis in children: a prospective case series with minimum two year follow-up

Concurrent Session 2B - Early Onset Scoliosis: paper no. 26SUMMARY: The growing rod has been the gold standard for the treatment of scoliosis in young children. However, such management requires multiple open surgeries under general anesthesia for rod distraction and is associated with numerous postoperative complications. To avoid such pitfalls, we utilized a magnetically-controlled growing rod (MCGR) implant. Our study found that the MCGR was safe and effective, allowing for distractions on a non-invasive out-patient basis at monthly intervals, eliminating the need for surgeries and their associated complications. Introduction: Traditionally, growing rods are the standard of treatment for young children with severe spinal deformities and significant residual growth potential. However, this requires repeated open distractions under general anesthesia and is associated with numerous post-operative complications. This report addresses the safety and efficacy of the MCGR implant for non-invasive out-patient distractions for scoliosis correction in young children. METHODS: This was a prospective, patient series of the MCGR procedure. From November 2009 to March 2011, five patients (n=3 female; n=2 male) were treated with the MCGR. In this study, we report the first three patients (2 females and 1 male) with minimum 2 years follow-up. All cases were non-invasively distracted using an external magnet on a monthly basis. Pre and post distraction radiographs were carried out to assess the Cobb’s angle, predicted versus achieved rod distraction length and spinal length. Clinical outcome assessment was performed with the pain score (Visual Analogue Scale) and the SRS-30 questionnaire. All procedural or rod related complications were recorded. RESULTS: The main correction of the Cobb’s angle was obtained in the initial surgery and was maintained. The mean monthly increase in T1-T12, T1-S1 and instrumented segment length was 1.6mm, 2.5mm and 1.2mm, respectively. Predicted versus actual length gain per distraction were similar. One case had a superficial wound infection and there was one event of loss of distraction. On last follow-up, no pain was noted and SRS-30 scores remained unchanged to baseline. CONCLUSION: The MCGR is a safe and effective procedure for the surgical treatment of scoliosis in children. The MCGR provides external distractions on an out-patient basis without the need for sedation or anesthesia, and that remote distraction allows more frequent lengthening of the rod that may more closely mimic physiologic growth.postprin

Adolescent Idiopathic Scoliosis. The Role of Low Dose Computed Tomography.

Continuous implementation of new operative methods for correction and stabilization of spinal deformities in young patients with AIS demands a detailed morphological analysis of the vertebral column. CT spine according to protocols available in daily clinical practice means high radiation dose to these young individuals. All examinations included in this thesis were performed on a 16-slice CT scanner. Examination of the chest phantom in paper I showed that the radiation dose of the spine (including 15 vertebrae) was 20 times lower than that of routinely used protocols for CT examination of the spine in children (0.38 mSv vs 7.76 mSv). In paper II the radiation dose and the impact of dose reduction on image quality were evaluated in 113 consecutive examinations with low-dose spine CT and compared with that of 127 CTs after trauma and 15 CTs performed according to a previously used ANV-protocol of a limited part of the vertebral column. The effective dose of the low-dose spine CT (0.01 mSv/cm scan length) was 20 times lower than that of the standard CT for trauma (0.20 mSv/cm scan length). The absorbed doses to the breasts, genital organs, and thyroid gland in the low-dose spine CT was 8, 265, and 22 times lower than the corresponding doses in CT for trauma. This significant dose reduction conveyed no impact on image quality with regard to answering the clinical questions at issue for the preoperative CTs and for the postoperative CTs after posterior corrective surgery. In paper III the low-dose CT showed to be a reliable method in the evaluation of screw placement in patients with AIS after posterior scoliosis surgery with titanium implants, using the new grading system for screw misplacement. Our proposed grading system for screw misplacement has shown to be feasible, practical, and easy to perform and is in line with the general agreement about the harmlessness of misplacement with minor pedicle breach. In paper IV the evaluation of the clinical and radiological outcome of 49 patients with AIS operated on with titanium “all-pedicle screw construct” showed an overall misplacement rate of 17 %. No evidence of neurovascular complications was reported. In parity with most of the reports in the literature the lateral- and medial cortical perforation were the most common types of screw misplacement (8 % and 6.1 % respectively)

An Empirical Examination of Frontal Sinus Outline Variability Using Elliptic Fourier Analysis: Implications for Identification, Standardization, and Legal Admissibility

The comparison of frontal sinus radiographs for positive identification has become an increasingly applied and accepted technique among forensic anthropologists, radiologists, and pathologists. However, the current method of outline comparison by visual assessment fails to meet evidence admissibility guidelines as set forth in the 1993 case of Daubert v. Merrell-Dow Pharmaceuticals, Inc. Specifically, no empirical testing of the uniqueness of frontal sinus outlines has ever been performed, there has been no evaluation of the probability of misidentification using the technique, there are no standards controlling the technique’s operation, and there are no subjective standards for confirming or rejecting a putative identification. Despite the fact that identifications based upon frontal sinus radiograph comparisons have been routinely accepted by scientists, medical examiners and law enforcement officers, these shortcomings could pose serious problems if forensic scientists were ever called upon to testify regarding such an identification in trial. This study investigated frontal sinus outline variability using Elliptic Fourier Analysis (EFA), a geometric morphometric approach that fits a closed curve to an ordered set of data points, generating a set of coefficients that can be treated as shape descriptors used as variables in discriminatory or other multivariate analyses, or used to reproduce the outline. By modeling 2-dimensional representations of frontal sinuses (as seen in posterior-anterior cranial radiographs) as closed contours by digitizing their outer borders, differences in their shapes were assessed quantitatively by comparing the Euclidean distances between the EFA-generated outlines. The probability of misidentification was assessed using likelihood ratios and posterior probabilities based on the EFA coefficients. Results showed that there is a quantifiable and significant difference between the shapes of different individuals’ frontal sinus outlines as represented by Euclidean distances, since distances between outlines of different individuals were shown to be significantly larger than those between replicates (simulated antemortem and postmortem) of the same individual. Likelihood ratios using EFA coefficients showed that the probability of a frontal sinus match given the correct identification versus the probability of a match from the population at large was very high, and therefore the probability of misidentification was very low. This study concluded that for individuals with sufficiently remarkable frontal sinus outlines, using EFA coefficients of digitized frontal sinus outlines to estimate the probability of a correct identification, and thereby confirm or reject a presumptive identification, is a reliable technique. Given these results, EFA comparison of frontal sinus outlines is recommended when it may be necessary to provide quantitative substantiation for a forensic identification based on these structures