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Author:Alhonnoro, Tuomas
Title:Vessel segmentation for ablation treatment planning and simulation
Verisuonten segmentointi ablaatiohoidon suunnittelua ja simulointia varten
Publication type:Master's thesis
Publication year:2010
Pages:[6] + 53      Language:   eng
Department/School:Informaatio- ja luonnontieteiden tiedekunta
Main subject:Lääketieteellinen tekniikka   (Tfy-99)
Supervisor:Ilmoniemi, Risto
Instructor:Pollari, Mika
OEVS:
Electronic archive copy is available via Aalto Thesis Database.
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Location:P1 Ark Aalto  575   | Archive
Keywords:vessel segmentation
vessel enhancement
liver
radiofrequency ablation
verisuonten segmentointi
kuvanparannus
maksa
radiotaajuusablaatio
Abstract (eng): In this work, a novel semiautomatic hybrid method for the segmentation of hepatic vasculature is presented, intended for numerical simulation of radio frequency ablation (RFA).
The method combines several of fundamental methods - multiscale enhancement filters, ridge-based region growning and skeleton-based post processing - in a new elegant way.
The proposed pyramid computation can provide full segmentation results in few minutes.
In addition, interactive tools were developed for exploration and manual editing of the segmented vessel tree designed especially from the simulation point of view.

The method was evaluated, both qualitatively and quantitatively, using four instances of three-phase contrast enhanced computed tomography CT) images of porcine liver and additional set of clinical routine human CT images.
While qualitative visualization is often the only evaluation in regard of vessel segmentation, this work has taken important step to provide a new evaluation protocol and full quantitative validation of the method.

The results prove that the proposed technique improves the accuracy of the vessel segmentation in comparison to previous approaches.
In addition, the method's suitability for simulation purposes has been illustrated.
Specifically, this method is capable of extracting 97% of hepatic vessels equal or above the critical threshold (3.0 mm in diameter) for ablation heat propagation.
But accuracy does not fall until subvoxel resolution.
Abstract (fin): Työssä kehitettiin puoliautomaattinen menetelmä maksan verisuonten segmentointiin; erityisesti radiotaajuusablaatio (RFA)-hoidon suunnittelua ja simulointia varten.
Nyt esitettävä menetelmä yhdistelee olennaisia elementtejä - moniresoluutio kuvanparannusta, kuvanharjanteisiin perustuvaa alueenkasvutusta, luurankomalliperusteista jälkikäsittelyä - tavalla, joka on uusi.
Esitetty pyramidiapproksimaatio suoriutuu laskennasta muutamissa minuuteissa.
Lisäksi kehitettiin interaktiivisia työkaluja monimuotoisen suonistopuun visualisointia ja editointia varten.

Menetelmä testattiin sekä kvalitatiivisesti että kvantitatiivisesti käyttäen neljää varjoainetietokonetomografia kuvasarjaa sian maksasta.
Lisäksi käytettiin muutamia kliinisiä kuvia.
Kvantitatiivista evaluaatiota varten kehitettiin uusi protokolla, joka poikkeaa vallitsevasta, visuaaliseen evaluointiin perustuvasta käytännöstä.

Työssä saavutetut tulokset osoittavat, että kehitetyllä menetelmällä voidaan merkittävästi parantaa verisuonten segmentointia.
Erityisesti, menetelmä pystyy havaitsemaan 97 % halkaisijaltaan 3.0 mm tai suuremmista maksan verisuonista, joiden tunnetaan vaikuttavan lämmön jakautumiseen RFA-hoidossa.
Menetelmän tarkkuus säilyy kuitenkin tyydyttävänä aina vokseliresoluutioon asti.
ED:2010-11-15
INSSI record number: 41300
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