Adenomyosis is a benign disease of the uterus characterized by ectopic endometrial tissue present in the myometrium.
The clinical diagnosis of adenomyosis is difficult because of nonspecific clinical presentation and the frequent coexistence of other pelvic diseases.
MRI is an effective technique for diagnosis,
it can be differentiated from other uterine pathology and help to plan treatment.
CLINICAL PRESENTATION:
Usually adenomyosis affects premenopausal multiparous women. The most frequent symptoms are menhorragia,
dysmenorrhea and dispareunia,
however,
between 3% and 35% of patients are asymptomatic.
It has long been suspected that the presence of adenomyosis provokes a condition of subfertility.
However at present it is not possible to show conclusively that adenomyosis can lead to subfertility.
MRI:
MRI is an accurate,
noninvasive technique for the diagnosis of adenomyosis.
The sensitivity and specificity of MRI for the diagnosis of adenomyosis is (78% -88%) and (67% -93%) respectively.
Some studies have shown that MRI is significantly better than transvaginal sonography (TVS),
whereas others have not observed significant differences between TVS and MRI.
However MRI may be more useful than TVS to determine the location and the extention of the injury,
and also to distinguish adenomyosis and leiomyoma,
which is of a great clinical relevance.
ANATOMIC BASES:
The uterine wall is composed by three layers; endometrium,
miometrium and serosa.
The inner myometrium,
or juntional zone myometrium ( JZ) also called "archimetra" lacks of recognisable protective layer or membrane,
forcing endometrial glands into direct contact with the miometrium.
MR T2-weighted images ( T2WI) of the uterus,
display in healthy women of reproductive age three distinct layers: endometrial mucosa,
which has a very high signal intensity the inner part of the myometrium,
immediately subendometrial,
which is called the juntional zone ( JZ) which has low signal intensity and the outer myometrium,
that show intermediate signal intensity (Fig.
1).
PHYSIOLOGYC CHANGES:
Physiologyc thickening of the JZ : During the first phase of the menstrual cycle,
the proliferative phase,
the JZ can be physiologically thickened.
Thickening between 8 and 12 mm at this stage should be considered nonspecific,
and it should be recommended to evaluate again during the secretory phase of the menstrual cycle (Fig.
2 ).
Uterine contractions: uterine contractions can manifest simulating myometrial masses,
with low signal on T2WI,
so we must set the differential diagnosis of leiomyoma or adenomiomas.
As the contractions are transient,
if they disappear in later images,
we can rule out the presence of uterine masses,
establishing the diagnosis of contractions ( Fig.
3).