02/Oct/2019

MRI for Endometriosis

Dr Livia Stanciulescu

Radiologist

Collaborator

Wellborn Endometriosis Centre

The examination of MRI in endometriosis is dedicated especially to the preoperative evaluation of deep endometriosis and complements the clinical and ultrasound examination. A qualitative examination should provide the surgeon with a more detailed map of the lesions, and begins with good communication between the gynaecologist and the imaging doctor and continues with a more detailed discussion between the imaging doctor and the patient.

Knowing the patient’s symptoms is of real use in guiding the examination protocol. Intravaginal and intrarectal gel instillation relax the cavities, thus leading to better visualisation of the walls and possible endometriosis nodules, with the possibility of evaluating the depth of the infiltration zone. By contrast offered by the gel, a better delineation of the peritoneal recesses (recto-vaginal and bladder-vaginal recession) is obtained. Also, the presence of gel reduces peristaltic artifacts.

The MRI ovarian endometriomas appearance is that of the cyst in the hypersignal in the T1 weight (bright white) and the hyposignal in the T2 weight (different shades of grey, determined by the presence of hemoglobin degradation products, in different stages).

Endometriotic nodules appear as a mass with infiltrative characters, spiked contour, with very low signal in T2 weighting, frequently with hyperintense cystic inclusions in T1 weighting, causing adhesions and retractable effect on the adjacent structures. The recto-vaginal septum requires special attention, lesions at this level are being frequently underdiagnosed.

For intestinal endometriosis, the role of the MRI exam is to preoperatively evaluate the depth of endometriotic infiltration, nodules that affect the muscularis propria and have an indication for resection. The distorted appearance of the digestive wall is a good indicator for infiltration of the muscular layer. The degree of stenosis is approximately appreciated, the rectal ampulla being a cavity organ whose maximum degree of repletion cannot be reproduced only with the help of gel instillation. An almost circumferential arrangement of the lesion is a criterion for a high degree of stenosis.

For urinary tract endometriosis the MRI examination, apart from detection, aims to assess the depth of endometriotic infiltration. If the pelvic ureters appear dilated, it should be mentioned in the written report, which may be a consequence of direct endometriotic infiltration or pelvic adhesion syndrome. The uterus-bladder recess is another frequently missed localization, often due to a maximal replenishment of the bladder or an exaggerated anteversion of the uterus, which may mask any lesions.

Uterine adenomyosis is a pathology commonly associated with endometriosis, but not only, but it may also accompany the presence of leiomyomas, hyperplasia or endometrial polyps. It has an MRI expression a thickening above the accepted normal limit (12 mm) of the myo-endometrial junction, frequently with included microcystic glandular dilations and irregular contour. It may have a diffuse or focal nodular appearance, sometimes polypoid, procident in the uterine cavity. The junctional area is influenced by the period of the menstrual cycle. It increases considerably in thickness during the menstrual period. To avoid a false-positive diagnosis, the time indicated for examination is the late proliferative phase.

anita radu

23/Aug/2019

Dr Livia Stanciulescu,

Medic Radiologist

Coloborator al Centrului de Endometrioza Wellborn

Examinarea IRM in endometrioza este dedicata in special evaluarii preoperatorii a endometriozei profunde si vine in completare examenului clinic si ecografic. O examinare calitativa trebuie sa ofere chirurgului o harta cat mai detaliata a leziunilor, incepe cu o buna comunicare intre medicul ginecolog si imagist si continua cu o discutie cat mai amanuntita intre medicul imagist si pacienta. Cunoasterea simptomatologiei pacientei este de un real folos in orientarea protocolului de examinare.

Instilarea de gel intravaginal si intrarectal destinde cavitatile, determinand astfel o mai buna vizualizare a peretilor si a eventualilor noduli de endometrioza, cu posibilitatea evaluarii profunzimii zonei de infiltrare. Prin contrastul oferit de gel se obtine si o mai buna delimitare a recesurilor peritoneale (recesul recto-vaginal si vezico-vaginal). In plus, prezenta gelului reduce artefactele de peristaltica.

Endometrioamele ovariene nu sunt tinta examinarii IRM, ele fiind diagnosticate de cele mai multe ori la evaluarea de rutina ecografica a uterului si anexelor. Aspectul IRM este acela de chist in hipersemnal in ponderatia T1 (alb stralucitor) si hiposemnal in ponderatia T2 (nuante diferite de gri, determinate de prezenta produsilor de degradare ai hemoglobinei, in diferite stadii).

Nodulii endometriozici au aspectul de masa cu caractere infiltrative, contur spiculat, cu semnal mult redus in ponderatia T2, frecvent cu incluziuni chistice hiperintense in ponderatia T1, determinand aderente si efect retractil asupra structurilor adiacente.
Spatiul Douglas, ligamentele utero-sacrate si insertia uterina a acestora sunt cele mai frecvente localizari ale endometriozei profunde pelvine. Septul recto-vaginal necesita o atentie speciala, o leziune la acest nivel fiind frecvent subdiagnosticata.

Endometrioza profunda se complica de multe ori cu aderente pelvine, determinand tractionare posterioara a uterului si ovarelor. Aspectul de “kissing-ovaries” este consecinta a sindromului aderential si un semnal de alarma pentru endometrioza profunda severa.

Endometrioza intestinala se localizeaza cel mai frecvent la nivelul rectului si jonctiunii recto-sigmoidiene. Rolul examenului IRM este de a evalua preoperator profunzimea infiltrarii endometriozice, un nodul care afecteza musculara proprie avand indicatie pentru rezectie. Aspectul distorsionat al peretelui digestiv, in “evantai”, este un bun indicator pentru infiltarea stratului muscular. Gradul de stenoza este apreciat aproximativ, ampula rectala fiind un organ cavitar al carui grad maximal de repletie nu poate fi reprodus doar cu ajutorul instilarii de gel. O dispunere aproape circumferentiala a leziunii este un criteriu pentru un grad ridicat de stenoza.

Endometrioza tractului urinar implica cel mai frecvent vezica urinara. Ca si in cazul nodulilor digestivi, examinarea IRM, in afara detectiei, are ca scop evaluarea gradului de profunzime al infiltrarii endometriozice. In cazul in care ureterele pelvine apar dilatate trebuie mentionat in raportul scris, aceasta putand fi o consecinta a infiltrarii endometriozice directe sau a sindromului aderential pelvin.

Recesul utero-vezical este o alta localizare frecvent omisa, de multe ori din cauza unei repletii maximale a vezicii urinare sau a unei anteroversii exagerate a uterului, acestea putand masca eventualele leziuni.

Adenomioza uterina este o patologie frecvent asociata cu endometrioza, dar nu numai, putand insoti prezenta de leiomioame, hiperplazia sau polipii endometriali. Ea reprezinta o proliferare a stromei si glandelor endometriale la nivelul miometrului si are ca expresie IRM o ingrosare peste limita normala acceptata (12 mm) a jonctiunii mio-endometriale, frecvent cu dilatatii glandulare microchistice incluse si contur neregulat. Poate avea aspect difuz sau focal nodular, uneori polipoid, procident in cavitatea uterina. Zona jonctionala este influentata de perioada ciclului menstrual, ea crescand considerabil in grosime in perioada menstruala. Pentru a evita diagnosticul fals pozitiv, momentul indicat pentru examinare este faza proliferativa tardiva.

Nodulii endometriozici localizati la nivelul peretelui abdominal au aceleasi caracteristici ca cei intrapelvini si o predilectie pentru ariile cicatriceale. O anamneza amanuntita poate atrage atentia examinatorului asupra acestei localizari. Pacienta deseori relateza interventii chirurgicale pelvine in antecedente, dureri in punct fix, ciclice, corelate cu perioada menstruala. Rar, endometrioza extrapelvina poate fi diagnosticata in abdomenul superior, diafragmatic sau intratoracic.

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