Ocena kakovosti slike pri magnetno resonančnem slikanju trebuha v otroškem obdobju - primerjava T2 TSE pulznih zaporedij z različnim načinom zajema podatkov : magistrsko delo

Klavs, Dejan (author), Ključevšek, Damjana (mentor), Podobnik, Janez (co-mentor)

Uvod: T2 poudarjena pulzna zaporedja so nepogrešljiva metoda pri MR slikanju trebuha. Na sliki pogosto prihaja do popačenj povezanih s premikanjem, bodisi zaradi premikanja preiskovanca ali premikanja struktur v trebuhu zaradi dihanja, peristaltike črevesja in pulziranja žil. Da se izognemo popačenjem premikanja, je bilo razvitih več različnih tehnik, ki le-ta zmanjšajo ali povsem izničijo. Namen: Ugotoviti s katerim od treh T2 TSE pulznih zaporedij z različnim načinom zajema podatkov dobimo tehnično najboljšo sliko. Primerjati in oceniti želimo kakovost slike T2 TSE pulznih zaporedij s prostim dihanjem preiskovancev. V primerjavo je vključeno T2 TSE pulzno zaporedje z uporabo dihalnega sprožilca in enaki pulzni zaporedji z uporabo PACE in BLADE tehnike slikanja. Metode dela: V raziskavo je bilo vključenih 29 pediatričnih preiskovancev. Poleg standardnega T2 TSE pulznega zaporedja z uporabo dihalnega sprožilca v transverzalni ravnini, smo v protokol dodali še T2 TSE pulzno zaporedje s PACE in BLADE tehniko slikanja. Pridobljene slike sta ocenjevala 2 neodvisna ocenjevalca. Ocenjevali smo 7 parametrov po sistemu 4-stopenjske lestvice, ki smo jo sestavili v ta namen in podali skupno oceno. Rezultati: Najboljše ocenjeno pulzno zaporedje pri večni ocenjevalnih parametrov je bilo pulzno zaporedje z uporabo dihalnega sprožilca, kar potrdi tudi skupna ocena vseh ocenjevalnih parametrov. Statistična primerjava ni pokazala značilnih razlik med tehniko z dihalnim sprožilcem in PACE tehniko, medtem ko primerjava tehnike dihalnega sprožilca in BLADE tehnike, kot tudi primerjava PACE in BLADE tehnike razkrije statistično značilne razlike med njimi. Upoštevajoč čas trajanja pulznega zaporedja, se je za najkrajšo izkazala tehnika z dihalnim sprožilcem, za najdaljšo pa PACE tehnika. Razprava in zaključek: Zaradi enostavnega zaznavanja dihalnega cikla se je tehnika dihalnega sprožilca izkazala za zelo uspešno in hitro metodo pri slikanju trebuha v otroškem obdobju. Pri PACE tehniki je na račun natančnega sledenja preponi v kombinaciji z neenakomernim dihanjem, prisotnih malce več popačenj, statistično daljši je tudi čas pulznega zaporedja. BLADE tehnika brez uskladitve z dihalnim ciklom preiskovanca se ni izkazala za uporabno pri MR slikanju trebuha otrok. Upoštevajoč ocene in čas trajanja pulznega zaporedja smo ugotovili, da je za klinično uporabo najbolj primerno pulzno zaporedje z uporabo dihalnega sprožilca.

• Language: Slovenian
• Keywords: popačenja, T2 TSE pulzno zaporedje, kakovost slike, dihalni sprožilec, PACE, BLADE
• Work type: Master's thesis/paper
• Organization: ZF - Faculty of Health Sciences
• Year: 2018
• PID: 20.500.12556/RUL-105420
• COBISS.SI-ID: 5552747
• Publication date in RUL: 28.11.2018

Secondary language

• Language: English
• Title: Quality assessment in abdominal magnetic resonance imaging in childhood - comparison of T2 TSE sequences with different acquisitions : master thesis

Abstract

Introduction: T2 weighted pulse sequences are an essential part of MR imaging of the abdomen. Motion artefacts on MR images are caused by patient’s movements, or movement of abdominal structures due to respiration, vascular pulsation and bowel peristalsis. Several different techniques which reduce or completely eliminate such artefacts have been developed. Purpose: The purpose is to determine which of the three T2 TSE pulse sequences with different techniques of data acquisition can produce technically the best image. Three T2 TSE free-breathing pulse sequences with respiratory gating, with PACE and BLADE techniques were compared and picture quality was evaluated. Methods: 29 paediatric patients with a mean age of 7,8 years were included in the research. Besides standard pulse sequences, which includes T2 TSE pulse sequence with respiratory gating in transverse plane, also two other sequences with PACE and BLADE techniques were added. Obtained images were evaluated by 2 independent radiologists according to the 4-point scale evaluating 7 different parameters and overall score of image. Results: Best rated pulse sequence in most of the evaluation parameters, was sequence with respiratory gating, which is also confirmed by overall grade of all evaluation parameters. Statistical comparison did not show any significant differences between the technique with respiratory gating and PACE technique, while the comparison of respiratory gating and BLADE technique, as well as PACE and BLADE technique, reveals statistically significant differences between them. Considering the time of acquisitions, respiratory gated sequence was measured as shortest and PACE technique was measured as longest. Discussion and conclusion: Because of simple detection of the respiratory cycle, the respiratory gated technique has been proved to be very useful and quick technique in abdominal imaging in childhood. Since the accuracy of the diaphragmatic motion gating is combined with irregular breathing, more artefacts on PACE sequence were shown. For the same reason, acquisition time was extended. BLADE technique without synchronized breathing cycle was not suitable in children abdominal MR imaging. Taking into consideration the grades and acquisition time, the pulse sequence with respiratory gating is proven to be the most optimal in clinical use.

• Keywords: artefacts, motion, T2 TSE pulse sequences, image quality, respiratory gating, PACE, BLADE