Complex Internal Carotid Artery Aneurysms

Complex intracranial aneurysms represent vascular lesions with attributes complicating their treatment. Giant intracranial aneurysms (GIA; ≥25 mm) are a rare subgroup of complex aneurysms with a particularly poor natural history. Due to their large size, giant aneurysms often present with cranial nerve dysfunctions. In this retrospective study, we aimed to provide a comprehensive description of the anatomical features of giant aneurysms in the internal carotid artery (ICA). Complex aneurysms are often difficult to approach directly, necessitating indirect treatment strategies. We therefore analysed a case series of bypass surgery and flow diversion in relation to the execution and outcomes in different segments of the ICA. All patients were admitted to the Helsinki University Hospital and for the analyses they were retrospectively recalled from the aneurysm database. For the series of giant aneurysms, we identified 125 patients with 129 GIAs (50 aneurysms in the ICA), from 1987 to 2007. For the series of bypass surgeries, included were 39 patients with 41 complex ICA aneurysms that were treated between 1998 and 2016. For the series of flow diversions, 62 patients with 76 ICA aneurysms were included from 2014 to 2019. In the treatment-oriented series, we analysed the internal carotid artery in segments, as this dictates the selection of treatment strategy. All the imaging studies and medical records were reviewed for relevant features in relation to aneurysms, complications and patient outcomes. The ICA was the most frequent location for GIAs in the cerebral arteries (39%) and most of these aneurysms were located specifically in the cavernous ICA segment (42%). Half of all GIAs presented mainly with symptoms of mass effect (50%). The cavernous GIAs were only rarely ruptured (10%) in contrary to the supraclinoid GIAs (36%). In general, wall calcification and intraluminal thrombosis were more seldom diagnosed in ruptured than in unruptured GIAs. In treatment of the complex ICA aneurysms with bypass procedures, the strategic goal of aneurysm treatment was achieved in 95% of cases (occlusion, 83%; flow modification, 12%). With flow diversion of the ICA aneurysms, 61% of aneurysms were occluded at 6-month follow-up and 69% at the latest follow-up. In both groups of treatment, the cavernous aneurysms became occluded slightly more often than the aneurysms in the supraclinoid region. Posttreatment large-scale strokes were rare (3-6%), but minor complications were seen more often. The pretreatment cranial nerve dysfunctions improved only moderately at best (cranial nerve-specific improvement rate of up to 60%). Respectively in groups of bypass and flow diversion, 74% and 85% of patients with unruptured aneurysms had favourable outcome at the latest follow-up. In both groups, only 25% of patients having unruptured aneurysms and presenting with poor functional status improved significantly to having a favourable outcome. The ICA is the most common location for GIAs and patients often present with symptoms of mass effect. Indirect treatment of complex ICA aneurysms with bypass procedures or flow diversion is feasible. Major treatment-related complications are rare, but minor complications occur at a non-negligible rate. Cranial nerve dysfunctions improve only in a proportion of patients. Lately, flow diverters have taken over the treatment of many complex ICA aneurysms, but the best treatment strategy should be assessed on a case-by-case basis, taking into consideration the burden of complex features of these aneurysms.Komplekseilla kallonsisäisillä aivovaltimopullistumilla eli aneurysmilla on ominaisuuksia, jotka tekevät aneurysmien hoidosta erityisen vaikeaa. Yhden alaryhmän muodostavat jättianeurysmat (≥25 mm), joilla on hoitamattomana erityisen korkea riski aiheuttaa aneurysmille tyypillinen hengenvaarallinen lukinkalvonalainen aivoverenvuoto. Kokonsa takia jättianeurysmat voivat tulla diagnosoiduksi myös esimerkiksi viereisten hermorakenteiden toimintahäiriöitä aiheuttaessaan. Kaikkiaan kompleksit aneurysmat, kuten jättianeurysmat, ovat harvinaisia ja siten niistä julkaistut aiemmat sarjat ovat olleet pääasiallisesti pieniä. Tässä retrospektiivisessä tutkimuksessa tavoitteemme oli seikkaperäisesti kuvailla sisemmän kaulavaltimon alueella sijainneiden jättianeurysmien anatomisia ominaisuuksia. Toisaalta kompleksien aneurysmien hoitamiseksi tarvitaan usein epäsuoria menetelmiä aneurysman sulkemiseksi verenkierrosta. Tämän takia analysoimme myös aivovaltimo-ohitusleikkausten sekä suonensisäisten virtausohjureiden (flow diverter) hoidolliset tulokset sisemmän kaulavaltimon aneurysmien osalta. Kaikki tutkimukseen sisällytetyt potilaat olivat olleet hoidossa HUS Helsingin yliopistollisessa sairaalassa, ja potilastiedot haettiin sarjoittain aneurysmarekisteristä vuosien 1989 ja 2019 väliseltä ajalta. Kaikki kuvantamistutkimukset sekä potilastiedot analysoitiin aneurysmiin, hoitotuloksiin ja hoidon komplikaatioihin liittyvien olennaisten tietojen osalta. Tutkimuksessamme totesimme, että sisempi kaulavaltimo on yleisin sijainti aivovaltimoiden jättianeurysmille ja tässä sijainnissa potilailla on usein aneurysman aiheuttamia aivohermo-oireita näkökyvyn häiriön muodossa. Epäsuora kompleksien aneurysmien hoito aivovaltimo-ohitteilla tai virtausohjureilla on toteuttamiskelpoista ja suurin osa aneurysmista sulkeutui seurannan aikana, mutta parhaimmillaan vain noin puolessa tapauksista aivohermo-oireet lievittyivät. Vakavat hoitoon liittyvät komplikaatiot olivat harvinaisia, mutta vähäisempiä tai ohittuvia oireita aiheuttaneita komplikaatioita todettiin useammin. Aivovaltimo-ohitusleikkaukset ovat erityisen vaativa hoitomuoto ja viime vuosina onkin suonensisäisillä virtausohjureilla hoidettu yhä enemmän komplekseja aneurysmia. Paras hoitomenetelmä tulisi valita tapauskohtaisesti ja punniten erilaisten aneurysman kompleksien ominaisuuksien aiheuttamaa kokonaishaastetta

Bypass Surgery for Complex Internal Carotid Artery Aneurysms : 39 Consecutive Patients

OBJECTIVE: Bypass surgery is a special technique used to treat complex internal carotid artery (ICA) aneurysms. The aim of this retrospective study is to provide a comprehensive description of treatment and outcome of complex ICA aneurysms at different ICA segments (cavernous, supraclinoid, ICA bifurcation) treated with bypass procedures. METHODS: We identified 39 consecutive patients with 41 complex ICA aneurysms that were treated with 44 bypass procedures between 1998 and 2016. We divided the aneurysms into 3 anatomic subgroups to review our treatment strategy. All the imaging studies and medical records were reviewed for relevant information. RESULTS: The aneurysm occlusion (n = 34, 83%) or flow modification (n = 5, 12%) was achieved in 39 aneurysms (95%). The long-term bypass patency rate was 68% (n = 30). Minor postoperative ischemia or hemorrhage was commonly seen (n = 20, 51%), but large-scale strokes were rare (n = 1, 3%). Preoperative dysfunction of extraocular muscles (cranial nerves III, IV, and VI) showed low-to-moderate improvement rates (20%-50%). Preoperative vision disturbance (cranial nerve II) improved seldom (22%). At the latest follow-up (mean; 51 months) 29 patients (74%) were independent (modified Rankin Scale CONCLUSIONS: Bypass surgery for complex ICA aneurysms is a feasible treatment method with an acceptable risk profile. Patients should be informed of the uncertainty related to improvement of pretreatment cranial nerve dysfunctions.Peer reviewe

Self-Organizing Maps for Analysis of Expandable Polystyrene Batch Process

Self-organizing maps (SOM) have been successfully applied in many fields of research. In this paper, we demonstrate the use of SOM-based method for the analysis of Expandable PolyStyrene (EPS) batch process. To this end, a data set of EPS-batch process was used for training a SOM. Reference vectors of the SOM were then classified by K-means algorithm into six clusters, which represent product types of the process. This SOM could also be used for estimating the optimal amounts of the stabilisation agent. The results of a validation data set showed a good agreement between the actual and estimated amounts of the stabilisation agent. Based on this model a Web application was made for test use at the plant. The results indicate that the SOM method can also be efficiently applied to the analysis of the batch process

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Diagnostic performance of short noncontrast biparametric 3‑T MRI for tonsillar infections : comparison with a full protocol including contrast‑enhanced sequence

Background We investigated whether a short, 5-min magnetic resonance imaging (MRI) protocol consisting of only axial T2-weighted and diffusion-weighted imaging (DWI) sequences can discriminate between tonsillar infections, peritonsillar abscesses and deeply extending abscesses in a retrospective, blinded, multireader setting. Methods We included patients sent by emergency physicians with suspected pharyngotonsillar infections who underwent emergency neck 3-T MRI from April 1 2013 to December 31 2018. Three radiologists (with 10−16 years of experience) reviewed the images for abscesses and their extension into deep neck spaces. Data were reviewed first using only axial T2-weighted Dixon images and DWI (short protocol) and second including other sequences and contrast-enhanced T1-weighted Dixon images (full protocol). Diagnostic accuracy, interobserver agreement, and reader confidence were measured. Surgical findings and clinical course served as standard of reference. Results The final sample consisted of 52 patients: 13 acute tonsillitis with no abscesses, 19 peritonsillar abscesses, and 20 deeply extending abscesses. Using the short protocol, diagnostic accuracy for abscesses across all readers was good-to-excellent: sensitivity 0.93 (95% confidence interval 0.87−0.97), specificity 0.85 (0.70−0.93), accuracy 0.91 (0.85−0.95). Using the full protocol, respective values were 0.98 (0.93−1.00), 0.85 (0.70−0.93), and 0.95 (0.90−0.97), not significantly different compared with the short protocol. Similar trends were seen with detecting deep extension. Interobserver agreement was similar between protocols. However, readers had higher confidence in diagnosing abscesses using the full protocol. Conclusions Short MRI protocol showed good-to-excellent accuracy for tonsillar abscesses. Contrast-enhanced images improved reader confidence but did not affect diagnostic accuracy or interobserver agreement. Relevance statement Short protocol consisting only of T2-weighted Dixon and DWI sequences can accurately image tonsillar abscesses, which may improve feasibility of emergency neck MRI. Key points • The short 3-T MRI protocol (T2-weighted images and DWI) was faster (5 min) than the full protocol including T1-weighted contrast-enhanced images (24 min). • The short 3-T MRI protocol showed good diagnostic accuracy for pharyngotonsillar abscesses. • Contrast-enhanced sequences improved reader confidence but did not impact diagnostic accuracy or interobserver agreement.© The Author(s) 2023. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.fi=vertaisarvioitu|en=peerReviewed

”Tarina se on tämäkin päivitys”: Kertomuksen vaarat -projekti sosiaalisessa mediassa

Puheenvuoro nostaa esiin Kertomuksen vaarat -tutkimusprojektin kohtaamia ja käsittelemiä tiedeviestinnällisiä haasteita sosiaalisessa mediassa. Projekti loi sosiaalisessa mediassa ainutlaatuisen joukkoistamiskampanjan, jolla kerättiin esimerkkejä kertomusmuodon välineellisestä käytöstä eri elämänalueilla. Kerättyjen esimerkkien popularisoivat narratologiset analyysit hankkeen Facebook-sivulla ovat herättäneet tunnereaktioita laidasta laitaan. Katsauksessa pohditaan kirjallisuustieteen, kertomuspuheen, affektien ja sosiaalisen median suhdetta sekä analysoidaan hankkeen omia toimintatapoja. Mitä "Kertomuksen vaarojen" sometoiminnasta voisi oppia

Airborne Laser Scanning Outperforms the Alternative 3D Techniques in Capturing Variation in Tree Height and Forest Density in Southern Boreal Forests

The objective of this study is to better understand the relationship between forest structure and point cloud features generated from certain airborne and space borne sensors. Point cloud features derived from airborne laser scanning (ALS), aerial imagery (AI), WorldView-2 imagery (WV2), TerraSAR-X, and Tandem-X (TDX) data were classified as features characterizing forest height and density as well as variation in tree height. Correlations between these features and field-measured attributes describing forest height, density and tree height variation were investigated at plot scale. From the field-measured attributes, basal area (G) and the number of trees per unit area (N) were used as forest density indicators whereas maximum tree height (H-max) and standard deviation in tree height (H-std) were used as indicators for forest height and tree height variation, respectively. In the analyses, field observations from 91 sample plots (32 m x 32 m) located in southern Finland were used. Even though ALS was found to be the most accurate data source in characterizing forest structure, AI, WV2, and TDX were also capable of characterizing forest height at plot scale with correlation coefficients stronger than 0.85. However, ALS was the only data source capable of providing separate features for characterizing also the variation in tree height and forest density. Features related to forest height, generated from the other data sources besides ALS, also provided strongest correlation with the forest density attributes and variation in tree height, in addition to H-max. Due to these more diverse characterization capabilities, forest structural attributes can be predicted more accurately by using ALS, also in the areas where the relation between the attributes of interest is not solely dependent on forest height, compared to the other investigated 3D remote sensing data sources.Peer reviewe

Airborne laser scanning outperforms the alternative 3D techniques in capturing variation in tree height and forest density in southern boreal forests.

ArticleBaltic Forestry. 24(2): 268-277. (2018)journal articl

Accuracy of High-Altitude Photogrammetric Point Clouds in Mapping

During the past decade, airborne laser scanning (ALS) has established its status as the state-of-the-art method for detailed forest mapping and monitoring. Current operational forest inventory widely utilizes ALS-based methods. Recent advances in sensor technology and image processing have enabled the extraction of dense point clouds from digital stereo imagery (DSI). Compared with ALS data, the DSI-based data are cheap and the point cloud densities can easily reach that of ALS. In terms of point density, even the high-altitude DSI-based point clouds can be sufficient for detecting individual tree crowns. However, there are significant differences in the characteristics of ALS and DSI point clouds that likely affect the accuracy of tree detection. In this study, the performance of high-altitude DSI point clouds was compared with low-density ALS in detecting individual trees. The trees were extracted from DSI-and ALS-based canopy height models (CHM) using watershed segmentation. The use of both smoothed and unsmoothed CHMs was tested. The results show that, even though the spatial resolution of the DSI-based CHM was better, in terms of detecting the trees and the accuracy of height estimates, the low-density ALS performed better. However, utilizing DSI with shorter ground sample distance (GSD) and more suitable image matching algorithms would likely enhance the accuracy of DSI-based approach.Peer reviewe

MRI of odontogenic maxillofacial infections : diagnostic accuracy and reliability

Objectives: To determine the diagnostic accuracy of emergency magnetic resonance imaging (MRI) in odontogenic maxillofacial infections, the clinical and surgical significance of MRI findings, and whether MRI can identify the tooth responsible for the infection. Methods: A retrospective cohort study reviewed 106 emergency neck MRI scans of patients with neck infections of odontogenic origin. The diagnostic accuracy of MRI in identifying abscesses was studied relative to surgical findings. Correlations were analyzed between various MRI findings and clinical results and outcomes, such as the surgical approach (intraoral vs. extraoral). The ability of MRI findings to predict the causative tooth was assessed in a blinded multi-reader setting. Results: Of the 106 patients with odontogenic infections, 77 (73%) had one or more abscesses. Imaging showed a sensitivity, specificity, and accuracy of 0.95, 0.84, and 0.92, respectively, for MRI diagnosis of an odontogenic abscess. Among the imaging findings, mediastinal edema was the strongest predictor of extraoral surgery. MRI showed bone marrow edema in the majority of patients, and multi-reader assessment showed good reliability. MRI was also able to predict the causative tooth accurately. Conclusions: Emergency neck MRI can accurately detect odontogenic abscesses and reliably point to the causative tooth. These results can increase the utility and reliance on emergency MRI in clinical decision-making.publishedVersionPeer reviewe