New Directions in 3D Medical Modeling: 3D-Printing Anatomy and Functions in Neurosurgical Planning

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked FilesThis paper illustrates the feasibility and utility of combining cranial anatomy and brain function on the same 3D-printed model, as evidenced by a neurosurgical planning case study of a 29-year-old female patient with a low-grade frontal-lobe glioma. We herein report the rapid prototyping methodology utilized in conjunction with surgical navigation to prepare and plan a complex neurosurgery. The method introduced here combines CT and MRI images with DTI tractography, while using various image segmentation protocols to 3D model the skull base, tumor, and five eloquent fiber tracts. This 3D model is rapid-prototyped and coregistered with patient images and a reported surgical navigation system, establishing a clear link between the printed model and surgical navigation. This methodology highlights the potential for advanced neurosurgical preparation, which can begin before the patient enters the operation theatre. Moreover, the work presented here demonstrates the workflow developed at the National University Hospital of Iceland, Landspitali, focusing on the processes of anatomy segmentation, fiber tract extrapolation, MRI/CT registration, and 3D printing. Furthermore, we present a qualitative and quantitative assessment for fiber tract generation in a case study where these processes are applied in the preparation of brain tumor resection surgery.Icelandic Innovation Fund RANNIS company Ossur University Hospital Landspital

Bone Mineral Density and Fracture Risk Assessment to Optimize Prosthesis Selection in Total Hip Replacement

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked Files. This article is open access.The variability in patient outcome and propensity for surgical complications in total hip replacement (THR) necessitates the development of a comprehensive, quantitative methodology for prescribing the optimal type of prosthetic stem: cemented or cementless. The objective of the research presented herein was to describe a novel approach to this problem as a first step towards creating a patient-specific, presurgical application for determining the optimal prosthesis procedure. Finite element analysis (FEA) and bone mineral density (BMD) calculations were performed with ten voluntary primary THR patients to estimate the status of their operative femurs before surgery. A compilation model of the press-fitting procedure was generated to define a fracture risk index (FRI) from incurred forces on the periprosthetic femoral head. Comparing these values to patient age, sex, and gender elicited a high degree of variability between patients grouped by implant procedure, reinforcing the notion that age and gender alone are poor indicators for prescribing prosthesis type. Additionally, correlating FRI and BMD measurements indicated that at least two of the ten patients may have received nonideal implants. This investigation highlights the utility of our model as a foundation for presurgical software applications to assist orthopedic surgeons with selecting THR prostheses.National University Hospital of Iceland Icelandic Research Fund "Rannis" Landspitali University Hospita

Quantitative Computed Tomography and image analysis for advanced muscle assessment

Medical imaging is of particular interest in the field of translational myology, as extant literature describes the utilization of a wide variety of techniques to non-invasively recapitulate and quantity various internal and external tissue morphologies. In the clinical context, medical imaging remains a vital tool for diagnostics and investigative assessment. This review outlines the results from several investigations on the use of computed tomography (CT) and image analysis techniques to assess muscle conditions and degenerative process due to aging or pathological conditions. Herein, we detail the acquisition of spiral CT images and the use of advanced image analysis tools to characterize muscles in 2D and 3D. Results from these studies recapitulate changes in tissue composition within muscles, as visualized by the association of tissue types to specified Hounsfield Unit (HU) values for fat, loose connective tissue or atrophic muscle, and normal muscle, including fascia and tendon. We show how results from these analyses can be presented as both average HU values and compositions with respect to total muscle volumes, demonstrating the reliability of these tools to monitor, assess and characterize muscle degeneration.This research has been supported by the University Hospital Landspitali Scientific fund.Peer reviewe

Cortical recruitment and functional dynamics in postural control adaptation and habituation during vibratory proprioceptive stimulation

Objective. Maintaining upright posture is a complex task governed by the integration of afferent sensorimotor and visual information with compensatory neuromuscular reactions. The objective of the present work was to characterize the visual dependency and functional dynamics of cortical activation during postural control. Approach. Proprioceptic vibratory stimulation of calf muscles at 85 Hz was performed to evoke postural perturbation in open-eye (OE) and closed-eye (CE) experimental trials, with pseudorandom binary stimulation phases divided into four segments of 16 stimuli. 64-channel EEG was recorded at 512 Hz, with perturbation epochs defined using bipolar electrodes placed proximal to each vibrator. Power spectra variation and linearity analysis was performed via fast Fourier transformation into six frequency bands (Δ, 0.5–3.5 Hz; θ, 3.5–7.5 Hz; α, 7.5–12.5 Hz; β, 12.5–30 Hz; γlow, 30–50 Hz; and γhigh, 50–80 Hz). Finally, functional connectivity assessment was explored via network segregation and integration analyses. Main results. Spectra variation showed waveform and vision-dependent activation within cortical regions specific to both postural adaptation and habituation. Generalized spectral variation yielded significant shifts from low to high frequencies in CE adaptation trials, with overall activity suppressed in habituation; OE trials showed the opposite phenomenon, with both adaptation and habituation yielding increases in spectral power. Finally, our analysis of functional dynamics reveals novel cortical networks implicated in postural control using EEG source-space brain networks. In particular, our reported significant increase in local θ connectivity May signify the planning of corrective steps and/or the analysis of falling consequences, while α band network integration results reflect an inhibition of error detection within the cingulate cortex, likely due to habituation. Significance. Our findings principally suggest that specific cortical waveforms are dependent upon the availability of visual feedback, and we furthermore present the first evidence that local and global brain networks undergo characteristic modification during postural control

Improving Prosthetic Selection and Predicting BMD from Biometric Measurements in Patients Receiving Total Hip Arthroplasty.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked DownloadThere are two surgical approaches to performing total hip arthroplasty (THA): a cemented or uncemented type of prosthesis. The choice is usually based on the experience of the orthopaedic surgeon and on parameters such as the age and gender of the patient. Using machine learning (ML) techniques on quantitative biomechanical and bone quality data extracted from computed tomography, electromyography and gait analysis, the aim of this paper was, firstly, to help clinicians use patient-specific biomarkers from diagnostic exams in the prosthetic decision-making process. The second aim was to evaluate patient long-term outcomes by predicting the bone mineral density (BMD) of the proximal and distal parts of the femur using advanced image processing analysis techniques and ML. The ML analyses were performed on diagnostic patient data extracted from a national database of 51 THA patients using the Knime analytics platform. The classification analysis achieved 93% accuracy in choosing the type of prosthesis; the regression analysis on the BMD data showed a coefficient of determination of about 0.6. The start and stop of the electromyographic signals were identified as the best predictors. This study shows a patient-specific approach could be helpful in the decision-making process and provide clinicians with information regarding the follow up of patients. Keywords: clinical decision making; database analyses; electromyography; machine learning; total hip arthroplasty.University of Reykjavik Icelandic National Hospital Rannis (Rannis Icelandic Research Fund (Rannsoknasjodur)) A&C M-C Foundation of Translational Myology, Padova, Ital

The chemistry and potential reactivity of the CO2-H2S charged injected waters at the basaltic CarbFix2 site, Iceland

Publisher's version (útgefin grein)The CarbFix2 project aims to capture and store the CO2 and H2S emissions from the Hellisheiði geothermal power plant in Iceland by underground mineral storage. The gas mixture is captured directly by its dissolution into water at elevated pressure. This fluid is then injected, along with effluent geothermal water, into subsurface basalts to mineralize the dissolved acid gases as carbonates and sulfides. Sampled effluent and gas-charged injection waters were analyzed and their mixing geochemically modeled using PHREEQC. Results suggest that carbonates, sulfides, and other secondary minerals would only precipitate after it has substantially reacted with the host basalt. Moreover, the fluid is undersaturated with respect to the most common primary and secondary minerals at the injection well outlet, suggesting that the risk of clogging fluid flow paths near the injection well is limited.This publication has been produced with support from Reykjavik Energy and the European Commission through the projects CarbFix (EC coordinated action 283148) and CO2-REACT (EC Project 317235).Peer Reviewe

Physical and cognitive impact following SARS-CoV-2 infection in a large population-based case-control study

© 2023. The Author(s).BACKGROUND: Persistent symptoms are common after SARS-CoV-2 infection but correlation with objective measures is unclear. METHODS: We invited all 3098 adults who tested SARS-CoV-2 positive in Iceland before October 2020 to the deCODE Health Study. We compared multiple symptoms and physical measures between 1706 Icelanders with confirmed prior infection (cases) who participated, and 619 contemporary and 13,779 historical controls. Cases participated in the study 5-18 months after infection. RESULTS: Here we report that 41 of 88 symptoms are associated with prior infection, most significantly disturbed smell and taste, memory disturbance, and dyspnea. Measured objectively, cases had poorer smell and taste results, less grip strength, and poorer memory recall. Differences in grip strength and memory recall were small. No other objective measure associated with prior infection including heart rate, blood pressure, postural orthostatic tachycardia, oxygen saturation, exercise tolerance, hearing, and traditional inflammatory, cardiac, liver, and kidney blood biomarkers. There was no evidence of more anxiety or depression among cases. We estimate the prevalence of long Covid to be 7% at a median of 8 months after infection. CONCLUSIONS: We confirm that diverse symptoms are common months after SARS-CoV-2 infection but find few differences between cases and controls in objective parameters measured. These discrepancies between symptoms and physical measures suggest a more complicated contribution to symptoms related to prior infection than is captured with conventional tests. Traditional clinical assessment is not expected to be particularly informative in relating symptoms to a past SARS-CoV-2 infection.Peer reviewe

Straumfræðileg hermun jökulhlaups niður suðurhlíðar Eyjafjallajökuls í apríl 2010: Ákvörðun Manningsstuðla

Jökulhlaup eru á meðal hættulegustu flóða sem verða á jörðinni. Jöklar heimsins eru að hörfa vegna hnattrænnar hlýnunar og mörg stöðuvötn undir jöklum að stækka. Á eldvirkum svæðum geta eldgos eða jarðhiti undir jöklum valdið jökulhlaupum. Á Íslandi eru bæði líf fólks sem og mannvirki í hættu vegna jökulhlaupa og víða þörf á að leggja mat á áhættu þeirra og útbreiðslu. Mat á viðnámsstuðlum er mikilvægur þáttur við hermun jökulhlaupa. Í þessu verkefni var lítið jökulhlaup niður Svaðbælisá úr Eyjafjallajökli hermt sem bæði æstætt og tímaháð flóð í straumfræðiforritinu HEC-RAS og mat lagt á viðnámsstuðla. HEC-GeoRAS var notað með landfræðiforritinu ArcGIS til þess að skilgreina landlíkanið út frá 5x5 m LiDAR skönnun jökulsins og næsta umhverfis. Mikil aska og aur hafði safnast fyrir í flóðfarveginum eftir hlaupið áður en landið var skannað. Mat var lagt á hækkunina út frá mælingum og landlíkanið leiðrétt. Viðnámsstuðlar og hámarksrennsli var ákvarðað með hliðsjón af tímasetningum flóðsins og flóðförum. Tímaháðar líkankeyrslur reyndust herma flóðið betur en æstæðir reikningar. Líkankeyrslur sýna fram á að nota þarf tvo mismunandi viðnámsstuðla fyrir flóðfarveginn. Viðnámsstuðlar úr líkankeyrslum, neðarlega í farveginum, gefa til kynna að þetta jökulhlaup hafi verið líkara venjulegum flóðum en þeim jökulhlaupum sem búið er að bakreikna hingað til. Þar fæst Manningsstuðull upp á n = 0,03 – 0,04 m-1/3s við rennslið 125 m3s-1 og 0,5-1,5 m flóðdýpt. Þetta er töluvert lægra en í þeim jökulhlaupum sem búið er að bakreikna, t.d. í Kötluhlaupinu 1918, þar sem hámarksrennsli nam allt að 300.000 m3s-1 og flóðdýpt allt að 25 m. Ofar í farveginum, á jökli og í miklum bratta, var stuðullinn metinn 0,1 – 0,13 m-1/3s. Þar var flóðdýpt mest um 3,2 m. Stuðullinn bendir til þess að mikið viðnám hafi verið í þeim hluta flóðfarvegarins og er nær afleiddum gildum fyrir önnur bakreiknuð jökulhlaup hér á landi

Electrically powered drying of fish meal

The fish meal industry is an important sector within the Icelandic fish industry and has applied technology in recent years. Fish meal processing is an energy intensive process. For better control of energy utilization in the process a mass- and energy flow model was set up for processing different raw material, and simultaneously for a better overview for the process. The model is a good tool to influence the quality of the fish meal products. The main aim of the project was to analyse the energy usage and contribute to improved energy utilization specially for the air drying with the new electric air heating equipment. The drying is the last step in the process and waste heat is utilized at previous stages in the process. The aim of the project is to estimate the benefits of using electricity to heat air for drying of fish meal. In that way it would be possible to reach the goal for the Icelandic marine sector to utilize exclusively domestic renewable energy for fish meal processing, reduce imports of oil for shore processing and reduce the carbon footprint. Measurements in the process were carried out for four kinds of raw material for evaluation of mass flow through the process. The electric air heater has proved its worth in HB Grandi fish meal factory in Vopnafjordur, Iceland in terms of operational security, energy utilization, control and maintenance.Matís - AV

Inflúenzubólusetning og COVID-19. Áhrif inflúenzubólusetningar, MBL magns og blóðflokka á alvarleika COVID-19 sjúkdóms.

Inngangur: COVID-19 hefur haft áhrif á líf flestra síðan faraldurinn hófst. Gríðarlega margir hafa veikst og ljóst er að ekki verði öll heimsbyggðin bólusett á allra næstu misserum. Mörgu er enn ósvarað í sambandi við sjúkdóminn eins og af hverju sumir veikist alvarlega á meðan aðrir sleppi vel. Vangaveltur hafa verið uppi hvort krossvirk mótefni hafi þar áhrif. Vísbendingar eru um að berklabólusetning hafi verndandi áhrif gegn alvarlegum COVID-19 sjúkdómi. Að sama skapi þekkist að mótefni gegn kvefvaldandi veirum HCoVs hafi að einhverju leiti kross-virka mótefnaverkun gegn peptíðum á SARS-CoV-2 og einnig eru vísbendingar um að inflúenzubóluefni gegn árlegu inflúenzunni geti mögulega veitt aukna vörn gegn COVID-19 en það hefur lítið verið rannsakað. Megin tilgangur rannsóknarinnar var að kanna hvort einstaklingar bólusettir gegn árlegu infúenzunni 2019 væru betur verndaðir gegn smiti eða alvarlegum COVID-19 sjúkdómi. Einnig var lífvísirinn MBL (mannan lektín) skoðaður ásamt blóðflokkum einstaklinga, fyrst hvort einstaklingar með lágan styrk MBL væru útsettari fyrir smiti eða alvarlegri COVID-19 og hvort tengsl væru milli blóðflokka og alvarleika veikinda. Efniviður og aðferðir: Framkvæmd var megindleg afturvirk ferilrannsókn á 510 COVID-19 sjúklingum úr fyrstu bylgju faraldurs. Fengar voru upplýsingar um bólusetningasögu, MBL, blóðflokka, kyn, aldur og innlagnir. Gögn um inflúenzubólusetningar á Íslandi 2019 fengust hjá Landlækni og tölur um mannfjölda fengust á heimasíðu hagstofunnar. Tölfræðivinna fór fram í Excel og tölfræðiforritinu R. Niðurstöður: Hlutfall inflúenzubólusettra í úrtaki var 24,1% en 16,3% Íslendinga voru bólusettir gegn inflúenzunni 2019. Kí-kvaðrat próf sýndi marktækan mun á fjölda innlagna í kjölfar SARS-CoV-2 smits hjá bólusettum einstaklingum og óbólusettum. Hlutfallslega lögðust 21% bólusettra inn á sjúkrahús m.v. 12% óbólusettra og áhættuhlutfallið var 1,7 fyrir bólusetta með 95% öryggisbili (1,11-2,63). Ekki reyndist marktækur munur milli hópa m.t.t. gjörgæsluinnlagna. Ekki fannst marktækur munur á MBL magni einstaklinga né tengsl milli blóðflokka og alvarleika veikinda í úrtakinu. Ályktanir: Inflúenzubóluefni reyndist ekki verndandi eins og talið var og ekki fannst munur milli MBL magns eða blóðflokka m.t.t. alvarleika COVID-19. Veikleiki er í rannsókninni þar sem ekki var tekið tillit til áhættuhópa meðal bólusettra sem eru útsettari fyrir alvarlegri veikindum. Áhugavert væri að stækka þýðið og lagskipta áhættuhópum og heilbrigðum til að fá betri sýn á virkni inflúenzubólusetninga m.t.t. COVID-19 sjúkdóms