Registration accuracy of the optical navigation system for image-guided surgery

Abstract. During the last decades, image-guided surgery has been a vastly growing method during medical operations. It provides a new opportunity to perform surgical operations with higher accuracy and reliability than before. In image-guided surgery, a navigation system is used to track the instrument’s location and orientation during the surgery. These navigation systems can track the instrument in many ways, the most common of which are optical tracking, mechanical tracking, and electromagnetic tracking. Usually, the navigation systems are used primarily in surgical operations located in the head and spine area. For this reason, it is essential to know the registration accuracy and thus the navigational accuracy of the navigation system, and how different registration methods might affect them. In this research, the registration accuracy of the optical navigation system is investigated by using a head phantom whose coordinate values of holes in the surface are measured during the navigation after different registration scenarios. Reference points are determined using computed tomography images taken from the head phantom. The absolute differences of the measured points to the corresponding reference points are calculated and the results are illustrated using bar graphs and three-dimensional point clouds. MATLAB is used to analyze and present the results. Results show that registration accuracy and thus also navigation accuracy are primarily affected by how the first three registration points are determined for the navigation system at the beginning of the registration. This should be considered in future applications where the navigation system is used in image-guided surgery.Kuvaohjatun kirurgian optisen navigointilaitteen rekisteröintitarkkuus. Tiivistelmä. Viimeisten vuosikymmenien aikana kuvaohjattu kirurgia on yleistynyt laajalti lääketieteellisten toimenpiteiden aikana ja se tarjoaa entistä paremman mahdollisuuden tarkkaan ja luotettavaan hoitoon. Kuvaohjatussa kirurgiassa navigointilaitteisto seuraa käytetyn instrumentin paikkaa ja orientaatiota operaation aikana. Navigointilaitteistoilla on erilaisia toimintaperiaatteita, joiden perusteella ne seuraavat instrumenttia. Yleisimmin käytetyt navigointilaitteistot perustuvat optiseen, mekaaniseen, tai sähkömagneettiseen seurantaan. Yleensä kuvaohjattua kirurgiaa käytetään pään ja selkärangan alueen kirurgisissa operaatioissa, joten on erittäin tärkeää, että navigointilaitteiston rekisteröinti- ja siten myös navigointitarkkuus tunnetaan, sekä erilaisten rekisteröintitapojen mahdolliset vaikutukset kyseisiin tarkkuuksiin. Tässä tutkimuksessa optisen navigointilaitteen rekisteröintitarkkuutta tutkitaan päämallin avulla, jonka pintaan luotujen reikien koordinaattiarvot mitataan navigointitilanteessa erilaisten rekisteröintitapojen jälkeen. Referenssipisteet kyseisille mittauspisteille määritetään päämallin tietokonetomografiakuvista. Mitattujen pisteiden, sekä vastaavien referenssipisteiden väliset absoluuttiset erot lasketaan ja tulokset esitetään palkkikuvaajien, sekä kolmiulotteisten pistepilvien avulla käyttäen apuna MATLAB-ohjelmistoa. Tulokset osoittavat, että rekisteröintitarkkuuteen ja siten navigointitarkkuuteen vaikuttaa eniten rekisteröintitilanteen alussa määritettävien kolmen ensimmäisen rekisteröintipisteen sijainti ja tämä tuleekin ottaa huomioon jatkossa tilanteissa, joissa navigointilaitetta käytetään kuvaohjatussa kirurgiassa

Painettujen johtimien venymän mittaus 3D-pinnalta

Tiivistelmä. Työn tavoitteena on löytää painettujen johtimien venymien mittaukseen soveltuvia menetelmiä, joiden avulla syntyvien venymien arvot pystytään mittaamaan mahdollisimman tarkasti ja luotettavasti myös 3D-tilanteissa. Aiemmin käytössä olleiden menetelmien avulla venymiä on pystytty tarkastelemaan pääasiallisesti 2D-tilanteissa. Työssä on käytetty apuna aiempien aiheeseen liittyvien tutkimusten tuloksia ja kirjallisuutta. Useita erilaisia menetelmiä löydettiin, joiden avulla venymien mittauksen voisi toteuttaa. Suurin osa näistä menetelmistä kuitenkin oli soveltumattomia johtimien venymien mittaukseen johtuen pääasiassa niiden koosta tai mittatarkkuudesta. Lupaavin menetelmä pohjautuu digitaalisen kuvakorrelaation ja valokenttäkameran yhteiskäyttöön, jonka avulla syntyneitä 3D-muodonmuutoksia voidaan tarkastella koko kappaleen alueella.Strain measurement of printed conductors from a 3D surface. Abstract. The aim of this bachelor’s thesis is to find suitable methods for measuring the strains of printed conductors, which can be measured as accurately and reliably as possible in 3D situations. Previously used methods have been able to examine strains mainly in 2D situations. The results of researches and literature have been used in this work. A lot of different methods were found to make strain measurements possible. However, most of these methods were unsuitable for measuring the strains of the conductors due to their size or dimensional accuracy. The most promising method is based on the combination of digital image correlation and light field camera, which can be used to measure 3D deformations in the desired area

Evaluation of an open access echocardiography service in the Netherlands: a mixed methods study of indications, outcomes, patient management and trends

Background: In our region (Eastern South Limburg, The Netherlands) an open access echocardiography service started in 2002. It was the first service of this kind in The Netherlands. Our study aims were: (1) to evaluate demand for the service, participation, indications, echocardiography outcomes, and management by the general practitioner (GP); (2) to analyse changes in indications and outcomes over the years. Methods: (1) Data from GP request forms, echocardiography reports and a retrospective GP questionnaire on management (response rate 83%) of 625 consecutive patients (Dec. 2002-March 2007) were analysed cross-sectionally. (2) For the analysis of changes over the years, data from GP request forms and echocardiography reports of the first and last 250 patients that visited the service between Dec. 2002 and Feb. 2008 (n = 1001) were compared. Results: The echocardiography service was used by 81% of the regional GPs. On average, a GP referred one patient per year to the service. Intended indications for the service were dyspnoea (32%), cardiac murmur (59%), and peripheral oedema (17%). Of the other indications (22%), one-third was for evaluation of suspected left ventricular hypertrophy (LVH). Expected outcomes were left ventricular dysfunction (LVD) (43%, predominantly diastolic) and valve disease (25%). We also found a high proportion of LVH (50%). Only 24% of all echocardiograms showed no relevant disease. The GP followed the cardiologist's advice to refer the patient for further evaluation in 71%. In recent patients, more echocardiography requests were done for 'cardiac murmur' and 'other' indications, but less for 'dyspnoea'. The proportions of patients with LVD, LVH and valve disease decreased and the proportion of patients with no relevant disease increased. The number of advices by the cardiologists increased. Conclusion: Overall, GPs used the open access echocardiography service efficiently (i. e. with a high chance of finding relevant pathology), but efficiency decreased slightly over the years. To meet the needs of the GPs, indications might be widened with 'suspicion LVH'. Further specification of the indications for open access echocardiography-by defining a stepwise diagnostic approach including ECG and (NT-pro)BNP-might improve the service

NDUFA1 p.Gly32Arg variant in early-onset dementia

Abstract Early-onset dementia (EOD) is highly heritable. However, in many EOD cases the genetic etiology remains unknown. Mitochondrial dysfunction is associated with neurodegeneration and the complex I (CI) deficiency is the most common enzyme deficiency in diseases related to oxidative phosphorylation. The X-chromosomal NDUFA1 gene is essential for the activity of CI. Mutations in NDUFA1 are associated with mitochondrial diseases especially with Leigh syndrome. CI deficiency is also associated with neurodegenerative diseases, such as Alzheimer’s disease (AD). The aim of this study was to evaluate the role of NDUFA1 variants in EOD patients. Next-generation sequencing panel was used to screen NDUFA1 variants in a cohort of 37 EOD patients with a family history of dementia or an atypical or rapidly progressive course of disease. We identified a hemizygous p.Gly32Arg variant in two brothers with AD. Subsequent screening of the variant in a larger cohort of EOD patients (n = 279) revealed three additional variant carriers (one male and two heterozygote females), suggesting that NDUFA1 variant p.Gly32Arg may play a role in neurodegenerative dementia

Long-term survival of patients with CLL after allogeneic transplantation: A report from the European Society for Blood and Marrow Transplantation

Even with the availability of targeted drugs, allogeneic hematopoietic cell transplantation (allo-HCT) is the only therapy with curative potential for patients with CLL. Cure can be assessed by comparing long-term survival of patients to the matched general population. Using data from 2589 patients who received allo-HCT between 2000 and 2010, we used landmark analyses and methods from relative survival analysis to calculate excess mortality compared with an age-, sex- and calendar year-matched general population. Estimated event-free survival, overall survival and non-relapse mortality (NRM) 10 years after allo-HCT were 28% (95% confidence interval (CI), 25-31), 35% (95% CI, 32-38) and 40% (95% CI, 37-42), respectively. Patients who passed the 5-year landmark event-free survival (N=394) had a 79% probability (95% CI, 73-85) of surviving the subsequent 5 years without an event. Relapse and NRM contributed equally to treatment failure. Five-year mortality for 45- and 65-year-old reference patients who were event-free at the 5-year landmark was 8% and 47% compared with 3% and 14% in the matched general population, respectively. The prospect of long-term disease-free survival remains an argument to consider allo-HCT for young patients with high-risk CLL, and programs to understand and prevent late causes of failure for long-term survivors are warranted, especially for older patients

New insights into the genetic etiology of Alzheimer’s disease and related dementias

Characterization of the genetic landscape of Alzheimer’s disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/‘proxy’ AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele