MAGNETIC-RESONANCE-IMAGING OF THE UTERUS IN-VIVO AND IN-VITRO AT AN ULTRA-LOW MAGNETIC-FIELD (0.02-T) - ASSESSMENT OF ITS NORMAL STRUCTURE AND OF LEIOMYOMAS

The purpose of this investigation was to analyze the normal anatomy an d leiomyomas of the uterus with an ultra low field (0.02 T) magnetic r esonance imaging (MRI) device. MR imaging was performed on 18 uteri, I I of which were imaged both preoperatively (in vivo) and as an operati ve specimen (in vitro), 6 only as an operative specimen, and 1 only pr eoperatively. All uteri were examined histologically after imaging. Th e junctional zone was much better delineated in vivo than in vitro, in dicating that its appearance on MR is partly due to blood flow. No str uctures contributing to its visibility in vitro could be demonstrated histologically. Twenty leiomyomas (size range 7-79 mm) in 12 uteri wer e found with MRI. They were slightly better discerned in vivo than in vitro. The leiomyomas, having no degenerative changes, had a signal in tensity which was the same or lower than that of the myometrium. On im ages obtained in vitro the signal intensity of these leiomyomas relati ve to that of myometrium correlated directly with their muscular conte nt (R = 0.74, p = .002). The authors conclude that the junctional zone is a sum of physiological and structural factors, the latter being re sponsible for its in vitro delineation. MR imaging of the uterus in vi tro did not give more information than MR imaging in vivo. All leiomyo mas larger than 10 mm could be detected, indicating that MR imaging at 0.02 T is an accurate method for the imaging of the uterine leiomyoma s.