Κατεύθυνση Ιατρική Φυσική-Ακτινοφυσική
Library of the School of Health Sciences

2020-09-23

2020

Tsakiri Kyriaki

Παντελής Καραΐσκος, Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Ιωάννης Σεϊμένης ,Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Βασίλειος Κουλουλίας, Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ

Γεωμετρικές παραμορφώσεις, ανεξάρτητες από την εφαρμοζόμενη ακολουθία, σε εικόνες απεικόνισης μαγνητικού συντονισμού (ΑΜΣ)

Greek

Geometric distortions, independent of the applied sequence, in magnetic resonance imaging (MRI) images

The work concerns the geometric deformations, that are independent of the applied sequence (Sequence Independent distortions, SI), in the Magnetic Resonance Imaging (MRI) images. Although MRI images have inherent deformations, their use is increasingly being used in radiotherapy applications, where high geometric accuracy is required, as is the case in the desing of Stereotactic Radiosurgery (SRS) treatment plan, which are characterized by high plan compliance and dose levels and it is therefore necessary to study the various types of geometric deformations involving MRI images.
Compared to CT, MRI gives greater contrast between soft tissues, as well as gives us important anatomical and functional information. However, in MRI there are geometric deformations, the separation of which can be done based on their dependence or not on the sequence selected for imaging.
In this work, the geometric deformations that are independent of the applied sequence are studied (Sequence Independent distortion, SI) using a model specially desingned and configured for the use in MRI for intracranial lesions which contains 1978 control points (Control Points-CP). After the model was scanned with CT and MRI, the central control points (CP) of CT were aligned with those of MRI and the CP-CT was determined with the CP-MRI.
In MRI scans, a 3T magnetic tomograph was used with and without correction of the deformations provided by the manufacturer, as well as a 1.5 T magnetic tomograph with correction. Then, given that the CT images have zero geometric deformation, the geometric deformations created by the MRI where calculated from the difference between the positions of the CP-MRI and CP-CT.
It has been observed that the corrections provided by the manufacturers reduce but not eliminate the prices of the geometric deformations which are greater with the increase of the magnetic field.

Health Sciences

Independent distortions, Magnetic Resonance Imaging (MRI)

No

0

Yes

24

62

File access is restricted only to the intranet of UoA.

https://pergamos.lib.uoa.gr/uoa/dl/object/2922836