MRI of the Uterus BENIGN Jeffrey C. Weinreb, M.D. FACR jeffrey.weinreb@yale.edu Yale University School of Medicine
Normal Anatomy M Junctional JZ Zone EE Junctional Zone is the inner layer or the myometrium
Routine GYN Protocol Prep Void prior to exam IV line NPO x 4 hrs Glucagon
Routine GYN Protocol Sag T2W FSE Respiratory trigger and/or anterior sat bands Short axis T2W (uterus or cervix) Cor or Axial T2W Axial T1W IP/OP Axial Fat Sat T1W Post-C C Fat Sat T1W with Subtractions Delayed Sag T2W FSE
Normal Uterus/Cervix
Uterine Leiomyoma Most common uterine neoplasm Occur in women of reproductive age and are under hormonal influence Enlarge during pregnancy or BCP use Regress after menopause Symptoms Dysmenorrhea Menorrhagia Infertility Pressure sensation
MRI of Uterine Leiomyoma Low signal on T2WIs Round Mass effec Well defined margins often with pseudocapsule Lacy or confluent hyperintensity
Uterine Leiomyoma As they grow, they may outgrow their blood supply, resulting in various types of degeneration Hyaline Myxoid Hyaline (homogeneous eosinophilic proteinaceous material) Myxoid (hyaluronic acid-rich mucopolysccharide gelitenous material) Cystic Hemorrhagic (red or BCPs) Calcific (red or carneous,, occurs in pregnancy or with
Uterine Leiomyosarcoma Sarcomatous transformation of preexisting leiomyoma is rare Diagnosis usually made as an incidental pathologic diagnosis in 0.5% or resected fibroids Most arise independently from myometrial smooth muscle cells
Uterine Leiomyoma Edema is common Scattered or diffuse Frequently prominent at periphery With extensive edema, get marked enhancement due to retention of contrast material within the abundant interstitial spaces Okizuka H, et al. J comput Assist Tomogr 1993;17:760-766 766
Suspect Leiomyosarcoma Lyphadenopathy, ascites,, or peritoneal seeding are unusual Rapid growth of leiomoyoma is not useful <3% of sarcomas have rapidly growing uterus <1% of rapidly growing leiomyomas contain leiomyosarcomas Hemorrhage is not useful Hemorrhage is not uncommon in fibroids but unusual in leiomyosarcomas High signal on T2WIs in >50% of mass is not useful Not uncommon in fibroids High signal on T2WIs and intense enhancement is not useful Seen with cellular leiomyomas (composed of compact smooth muscle cells with little or no collagen) Irregular or indistinct margin is suggestive
Uterine Leiomyoma Differential Diagnosis Uterine sarcoma Leiomyosarcoma Mixed mullerian tumor Endometrial stromal sarcome Adenomyosis Solid ovarian masses (fibroma( fibroma, fibrothecoma,, Brenner tumor) Myometrial contractions Endometrial cancer Endometrial polyp Gestational Trophoblastic Disease Retained products of conception
Ovarian Fibromas/Fibrothecomas Gonadal stromal cell origin Most common solid primary ovarian tumor Benign Fibromas consist of intersecting bundles of spindle cells that produce large amount of collagen Fibrothecomas also contain theca cells Cystic degeneration and edema On MRI resemble fibroids Diff Dx includes intraligamentous leiomyoma, endometrioma,, ovarian fibromatosis,, and Brenner tumor
Bridging Vascular Sign Vessels that extend from the uterus to supply a pelvic mass indicate the uterine origin of a juxtauterine mass Caused by feeding vessels that arise from the uterine arteries In one study, it was present in in 20/26 exophytic leiomyomas and absent in all other adnexal masses, resulting in a diagnostic accuracy of 80% Kim JC, et al. J Comput Assist Tomogr 2000;24:57060 But, ovarian malignancies that invade the uterus may also show this sign Kim SH, et al. J Comput Assist Tomogr 2001;25:36-42
Exophytic fibroid or fibroma? Fibroid A mass may originate from the periphery of the ovary, so the identification of an apparently normal adjacent ovary does not exclude an ovarian origin
Ovarian Vascular Pedicle Sign If you can trace asymmetrically enlarged gonadal veins anterior to psoas muscle and common iliac vessels into a pelvic mass, it indicates that the ovary is the organ of origin Identified in 92% of ovarian masses Also seen in 13% of subserosal uterine myomas The ovarian veins form a plexus in the broad ligament that communicates with the uterine plexus Lee JH, et al. AJR 2003;181:131-137 137
Adenomyosis Hormonally resistant endometrial glands (basalis type) and stroma deep within the myometrium Smooth muscle hyperplasia and hypertrophy induced around glands Histologically present in >40% women Tamai K, e tal. RadiolGraphics 2005;25:21-40
MR Findings in Adenomyosis Broadening of junctional zone Poorly defined low signal contiguous with junctional zone Low signal myometrial mass (adenomyoma) Punctate high signal on T2WIs (glandular cystic changes) high resolution images helpful
Adenomyosis > 12 mm = adenomyosis 8-11 mm = c/w adenomyosis if clinical findings < 7 mm = nornal
Pitfalls Junctional zone may widen (focally or diffusely) on days 1-21 2 of menstrual cycle Junctional zone may widen with dysmenorrhea Uterine contractions Focal Striated
Summary Leiomyoma Round Mass effect Well defined margins often with pseudocapsule Lacy or confluent hyperintensity Adenomyoma Oval with long axis paralleling uterus Relatively little mass effect Indistinct margins Punctate hyperintense foci Leiomyoma coexist in 35-55% of cases if adenomyosis
Adenomyosis and Endometriosis Most of the major authors of the first half of the past century dealing with the disease considered pelvic endometriosis and uterine adenomyosis as variants of the same disease process Adenomyosis used to be know as endometriosis interna or inside-out endometriosis They are now thought to be different diseases, but there is a high association between endometriosis and adenomyosis,, and vice versa Leyendecker G (2000) Endometriosis is an entity with extreme pleiomorphism.. Hum Reprod 15, 4 74