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Comparison between diffusion‐weighted imaging, T 2 ‐weighted, and postcontrast T 1 ‐weighted imaging after MR‐guided, high intensity, focused ultrasound treatment of uterine leiomyomata: Preliminary results
Author(s) -
Jacobs Michael A.,
Gultekin David H.,
Kim Hyun S.
Publication year - 2010
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.3475940
Subject(s) - magnetic resonance imaging , effective diffusion coefficient , ultrasound , medicine , diffusion mri , nuclear medicine , uterine fibroids , radiology , pathology
Purpose : To investigate the comparison between diffusion‐weighted imaging (DWI), T 2 ‐weighted imaging,( T 2 WI )and contrastT 1 ‐weighted imaging(cT 1 WI )in uterine leiomyoma following treatment by magnetic resonance imaging‐guided, high intensity focused ultrasound surgery (MRg‐HIFUS). Methods : Twenty one patients ( 45 ± 5 yrs )with clinical symptoms of uterine leiomyoma (fibroids) were treated by MRg‐HIFUS using an integrated 1.5T MRI‐HIFUS system. MRI parameters consisted of DWI,T 2 WI , andT 1 ‐weighted fast spoiled gradient echo before and after contrast. The post‐MRg‐HIFUS treatment volume in the fibroid was assessed bycT 1 WI and DWI. Trace apparent diffusion coefficient maps were constructed for quantitative analysis. The regions of the treated uterine tissue were defined by a semisupervised segmentation method called the “eigenimage filter,” using bothcT 1 WI and DWI. Signal‐to‐noise ratios were determined for theT 2 WI pretreatment images. Segmented regions were tested by a similarity index for congruence. Descriptive, regression, and Bland–Altman statistics were calculated. Results : All the patients exhibited heterogeneously increased DWI signal intensity localized in the treated fibroid regions and were colocalized with thecT 1 WI defined area. The mean pretreatmentT 2 WI signal intensity ratios wereT 2 WI / muscle = 1.8 ± 0.7 andT 2 WI / myometrium = 0.7 ± 0.4 . The congruence between the regions was significant, with a similarity of 84% and a difference of 8% between the regions. Regression analyses of thecT 1 WI and DWI segmented treatment volumes were found to be significantly correlated( r 2 = 0.94 , p < 0.05 )with the linear equation,(cT 1 WI ) = 1.1 ( DWI ) − 0.66 . There is good agreement between the regions defined by cT1WI and DWI in most of the cases as shown from the Bland–Altman plots. Conclusions : Diffusion‐weighted imaging exhibited excellent agreement, congruence, and correlation with thecT 1 WI ‐defined region of treatment in uterine fibroid. Therefore, DWI could be useful as an adjunct for assessing treatment of uterine fibroids by MRg‐HIFUS.