Radiological imaging of endometriosis.

Dr/ ABD ALLAH NAZEER. MD.

Endometriosis is defined as the presence of endometrial epithelium and stroma in an ectopic site outside the uterine cavity . Endometriosis occurs in 10% of the female population and almost, exclusively, in women of reproductive age . The most common symptoms are dysmenorrhea, dyspareunia, pelvic pain, and infertility although endometriosis may be asymptomatic . Adenomyosis is the presence of endometrial glands and stroma within the myometrium and it is the cause of uterine enlargement, menorrhagia, and dysmenorrhea and. The most common sites for endometrial implantation within the pelvis are the ovaries, broad and round ligaments, fallopian tubes, and cervix. Endometriosis can affect the woman in the reproductive age; however, it cannot be accurately diagnosed by clinical criteria alone. In addition, the transabdominal and transvaginal US are not as accurate as MRI.

Superficial endometriosis.

In superficial endometriosis – also known as Sampson's syndrome - superficial plaques are scattered across the peritoneum, ovaries and uterine ligaments. These patients tend to have minor symptoms and usually also less structural changes in the pelvis. At laparoscopy, these implants may be seen as superficial powder-burn or gunshot lesions.

In deep pelvic endometriosis - also called Cullen's syndrome - there is subperitoneal infiltration of endometrial deposits. The symptoms are more severe and related to the localization and depth of invasion. MRI is of use for the diagnosis of deep infiltrating endometriotic lesions and for the assessment of disease extension. Preoperative mapping of disease extension is important to decide whether surgical intervention is indicated, and if so, for planning complete surgical excision.

Deep pelvic endometriosis.

Endometriomas - also known as chocolate cysts Develop when superficial endometriotic lesions on the surface of the ovary invaginate. Blood produced by such an implant during each menstrual cycle cannot escape and will accumulate within the ovary, forming a cyst known as an endometrioma.Endometriomas present as complex cystic masses, often thick-walled with a homogeneous content. On transvaginal ultrasound, endometriomas may be seen as thick-walled cysts with low level echoes. On the left a transvaginal ultrasound image and the corresponding laparoscopic image during cystectomy.

Sites.Pelvic:-Uterine= adenomyosis(50%).Extra-uterine:-Ovary 30%.- Pelvic peritoneum 10%.-Fallopian tube.-Vagina.-Bladder &rectum.-Pelvic colon.- Ligaments.

Extra-pelvicUmbilicus.Scars(Laparotomy).Lung &pleura.Others.

Symptomatology.- Pelvic pain(65%). . Dysmenorrhea, especially suggestive of endometriosis the pain if it occurs after years of pain free menstruation. . Deep dyspareunia.. Chronic pelvic pain.. Ovulation pain with menstrual irregularity.. Other types of pain- Sciatica.-Infertility(35%).

GIT symptoms:. Diarrhea.. Constipation.. Changes in bowel habits.. Rectal bleeding.. Pain with defecation.. Tenesmus.. Abdominal distension.. Small caliber stool..Colicky abdominal pain.. Bowel obstruction.. Bowel perforation.

Urinary symptoms:-Urgency.- Frequency.- Supra-pubic pain.- Flank pain.- Urge incontinence.- Dyspareunia.- Hematuria.- Dysuria.- Backache.- Hydronephrosis.

Normal anatomy of the female pelvis. (a, b) Axial (a) and sagittal (b) T2-weighted MR images show the uterosacral ligaments (arrows in a), rectovaginal pouch (* in b), and retrocervical area (outlined in b). (c, d) Laparoscopic images show the uterosacral ligaments (arrows in c), rectovaginal pouch (* in c), and retrocervical area (outlined in d). (e) Drawing of the female pelvis (oblique coronal view, superoinferior orientation) shows the ureters (arrows), uterosacral ligaments (arrowheads), cardinal ligaments and parametrium (black *), and round ligaments (white *). Note that the ureters course lateral to the uterosacral ligaments and immediately caudal to the cardinal and broad ligaments.

Normal anatomy of the female pelvis.

Ultrasound examination:Sonographic examinations took place on two perpendicular planes using PHILIPS HD11 instrument. Pelvic transabdominal US was performed by using a 3.5-MHz transducer and transvaginal US examination with 8-MHz transducer. During each Sonographic examination, the uterine borders, whether regular or irregular, uterine size, myometrial echotexture and the presence of focal areas with ill-defined borders or abnormal echotexture were described. When these areas were present, the following criteria of adenomyosis were evaluated: presence of heterogeneity, increased or decreased areas of echogenicity, or presence of myometrial cysts. Another type of ultrasound that we used in our study is trans-rectal ultrasound which is necessary in the evaluation of deep infiltrating endometriosis involving recto-vaginal and utero-sacral ligaments but unfortunately we have no cases that have the deep infiltration of these regions.

Radiological imaging.

MRI protocols:MRI performed using T2 weighted images required 4 mm slices in the sagittal, coronal, and axial planes related to the orientation of the uterine cavity that used fast spin echo sequences in all the three planes. T1 weighted spin echo and gradient echo images were obtained both with and without fat saturation for all patients. High-resolution body coils were used for data acquisition, and exams were completed in 30–45 min. T1 weighted fat saturated and T2 weighted images for four major criteria:

1.Borders, size and uterine symmetry.

2.Maximal junctional zone (JZ max) thickness and/or the presence of an ill-defined, relatively homogenous, low signal intensity, myometrial area.

3.Maximal (JZ max) to myometrial thickness ratio using the maximal thickness of JZ and the corresponding thickness of the entire myometrium obtained at the same level.

4.High intensity spots within the myometrium, the presence of T1 bright/T2 dark signals, suggesting the existence of endometriosis in any of the anatomical locations.

Sagittal T2-weighted image with fat suppression of 27-year-old woman in second part of her cycle. Uterus is evaluated between isthmus and end of uterine cavity (white lines). Junctional zone (short arrows) should be measured from several sites on anterior and posterior walls. Junctional zone measure can be compared with entire thickness of myometrium (long arrows) evaluated at same site.

Role of the Junctional Zone Ultrasound studies have been paramount in understanding the role of the junctional zone, which is intricately linked with its structural organization and biochemical properties. Pelvic ultrasound, performed transabdominally in the 1980s and later endovaginally in the 1990s, has permitted observation of contractions of the junctional zone occurring in the nongravid uterus. Video recordings have identified these contractions with a speed of 1.2–1.7 mm/s with a frequency of 3–5 contractions/min. Contractions are classified according to their direction: from the uterine cervix toward the body, from the body to the cervix, or both simultaneously . These junctional contractions have been secondarily described on MRI with particular dynamic sequences. They appear as thin bands perpendicular to the junctional zone and in low signal intensity on T2-weighted images. This signal has been partly explained by the venous vasoconstriction that reduces the quantity of circulating blood in the myometrium. In 2007, Kido et al. used MRI to illustrate the influence of oral contraceptives on uterine contractions. It was clearly shown that these contractions have an amplitude, a frequency, and a direction that correlate with the phase of the menstrual cycle. Thus, in the first part of the cycle, contractions occur from the cervix toward the body and increase in intensity until ovulation. These contractions participate directly in the transport of spermatozoids toward the ovum as reported by Kunz and colleagues by utilizing inert particles. confirmed this hypothesis by studying the strong link between contractions issued from the junctional zone and fertility.

Adenomyosis is the presence of endometrial glandular cells and cells of the chorion more than 2.5 mm from the endometrium-myometrium interface. A hypertrophic reaction of the smooth-muscle cells surrounding the ectopic glands is another important element of diagnosis . Involvement of the myometrium can include the entire interface, termed “diffuse adenomyosis,” or it can present in a limited area, termed “focal adenomyosis.” These two forms have similar frequency on hysterectomy samples but are rarely associated. Adenomyoma, a localized confluence of adenomyotic glands forming a mass, constitutes an unusual form of adenomyosis.The actual prevalence of adenomyosis remains unknown. Risk factors for adenomyosis—most notably, the existence of prior endouterine surgery—were isolated. Multiparity is another risk factor, which appears contradictory to the not so well-established link between adenomyosis and infertility. Adenomyosis preferentially affects women between 40 and 50 years old; however, most forms are asymptomatic, explaining perhaps the lower rate of detection in young women. A positive diagnosis of adenomyosis cannot be made reliably on the basis of clinical examination alone. Supporting evidence, including MRI findings, is necessary to entertain and confirm the diagnosis.

Radiographic features:Imaging features are variable and in many instances very subtle. Three (some say four) forms can be distinguished:diffuse adenomyosis: most commonfocal adenomyosis and adenomyoma: some consider these as separate (see below).cystic adenomyosis and adenomyotic cyst: rareAdenomyosis is usually relatively generalized, affecting large portions of the uterus (typically the posterior wall), but sparing the cervix. Despite often marked enlargement of the uterus, the overall contour is usually preserved.In some cases it may also be localized, forming a mass. In such cases the term adenomyoma may be used, although there appears to be some disagreement about whether the terms focal adenomyosis and adenomyoma refer to exactly the same entity (please refer to the article on adenomyoma for further discussion).A rare variant is cystic adenomyosis which is believed to be the result of repeated focal hemorrhages resulting in cystic spaces filled with altered blood products.

Pelvic ultrasound:Ultrasound is usually the first and often the only imaging modality employed to investigate menorrhagia and dysmenorrhea. Unfortunately, the sonographic features of adenomyosis are variable, and may be absent. The reported sensitivity and specificity of trans-abdominal ultrasound are 32-63 % and 95-97 % respectively .The spectrum of findings includes:normal appearing uterus, focal or diffuse bulkiness, typically of the posterior wall heterogeneous echogenicity (heterogenous myometrial echotexture)

hyperechoic: islands of endometrial glandshypoechoic: associated muscle hypertrophya "venetian blind" appearance may be seen due to subendometrial echogenic linear striations & acoustic shadowing where endometrial tissues cause a hyperplastic reaction.

small myometrial: sub endometrial cysts: thickening of the transition zone sometimes can be visualized as a hypoechoic halo surrounding the endometrial layer of 12 mm or more thickness subendometrial echogenic linear striationssubendometrial echogenic nodulesWhen an adenomyoma is present, then appearances may closely mimic those of a uterine fibroid, which may also co-exist.

Hysterosalpingogram (HSG):May show diverticula extending into the myometrium .CT is unable to diagnose adenomyosis: but may suggest its presence when uterine enlargement is present. Distinguishing between adenomyosis and uterine fibroids on CT is difficult if not impossible, although presence of calcifications strongly favours the latter .Pelvic MRI: MRI is the modality of choice to diagnose and characterize adenomyosis, and T2 weighted images (sagittal and axial) are most useful. It has a very diagnostic accuracy with a sensitivity of 78-88% and a specificity of 67-93% .

The most easily recognised feature is thickening of the junctional zone of the uterus to more than 12 mm, either diffusely or focally (normal junctional zone measures no more than 5 mm) T2: typically a region of adenomyosis appears as an ill-defined ovoid/diffuse region of thickening often with small high T2 signal regions representing small regions of cystic change the region may also have a striated appearance. T1: Foci of high T1 signal are often seen, indicating menstrual hemorrhage into the ectopic endometrial tissues. T1 C+ (Gd): contrast enhanced MR evaluation is usually not indicated in adenomyosis, however if performed, it shows enhancement of the ectopic endometrial glands.

HSG with adenomyosis of the uterus.

CT with adenomyosis of the uterus.

42-year-old woman who presented with chronic pelvic pain. Coronal (A) and axial (B) T2-weighted images reveal cystic area surrounded by low-signal-intensity ring (arrow). Overall appearance on MRI is that of cystic adenomyoma.

36-year-old woman who underwent MRI evaluation for polymyomatous uterus discovered on ultrasound. On sagittal T2-weighted image, posterior myoma (black arrow) is visible in frank hyposignal. Focal adenomyosis (white arrow) is visible on anterior uterine wall, presenting as ill-defined area in hyposignal-containing cysts. Hyperintense linear or reticulated streaks extend from endometrium into markedly thickened anterior myometrium (arrowheads).

Diffuse adenomyosis of the uterus.

Adenomyosis of the uterus.

Diffuse adenomyosis of the uterus.

Focal uterine adenomyosis.

Adenomyosis with endometrioma.

MRI (sagittal T2WI) shows adenomyosis with abnormal increase in thickness of junctional zone (12 mm) and abnormal high T2 SI of the myometrium represents abnormal stromal glands inside the myometrium. B: MRI (coronal T2WI) shows the same finding as well as bilateral ovarian simple cysts.

Sagittal transvaginal sonography demonstrates myometrial anechoic lacunae specific of adenomyosis involving the ventral and the dorsal myometrium (A). Transversal transabdominal examination shows a very large asymmetric uterus with thickening of the dorsal myometrium.. (B). Transvaginal sonography demonstrates diffuse adenomyosis involving the ventral myometrium and a dorsal subserous leiomyoma. Sagittal T2-weighted magnetic resonance image through the uterus shows numerous high-intensity spots in the inner myometrium, thickening of junctional zone (JZ) (13 mm) and ratio max >40% (D). Axial T2-weighted magnetic resonance image demonstrates diffuse thickening of JZ both ventrally and dorsally, consistent with severe adenomyosis. Numerous foci of high signal representing the heterotopic endometrium are present (E). Sagittal T2-weighted magnetic resonance image through the uterus (F): there is an ill-defined mass centred around the endometrium. Several foci of increased signal consistent with heterotopic endometrium are present in the inner myometrium without mass effect on the endometrial cavity. In contrast, leiomyoma is very hypointense and has well-defined borders (F).

Linear striations, sonographic findings suggestive of adenomyosis, in a 47-year-old woman with pelvic pain and dysmenorrhea. A, Sagittal transvaginal sonogram shows anenlarged uterus. A heterogeneous echo texture involving the anterior myometrium is shown with linear striated shadowing(arrowheads). B, Sagittal fat-suppressed T2-weighted MRI shows marked adenomyosis involving the anterior uterine wallmanifested as a thickened junctional zone with scattered myometrial cysts (arrows). C, Sagittal T1-weighted gradient echo MRI (TR, 270 milliseconds; TE, 5 milliseconds) obtainedafter administration of gadolinium dimeglumine shows enhancement of the endometrium and myometrium. Myometrial cysts (arrows) do not show enhancement

Polypoid AdenomyomaAn adenomyoma is occasionally located in a submucosal or subserosal position. A submucosal adenomyoma manifesting as a polypoid mass protruding into the endometrial cavity has been termed “polypoid adenomyoma. This lesion usually arises from the uterine corpus, occasionally from the lower uterine segment and cervix. It can be seen as a pedunculated or sessile mass. Its appearance on MRI as an uncommon variant of adenomyosis has been described. Use of the term polypoid adenomyoma has been controversial. Although some authors have discussed this lesion as a distinct entity, the gynecologic pathologic literature reflects the opinion that the term polypoid adenomyoma refers to a polypoidal form of a circumscribed adenomyotic mass.Atypical Polypoid AdenomyomaThis is an uncommon variant of polypoid adenomyoma characterized by atypical endometrial glands and often squamous metaplasia and a cellular smooth muscle stroma. Before its delineation, this lesion was often considered malignant. The distinction between the typical and atypical adenomyoma depends on histologic examination because the radiologic findings are similar.

Polypoid adenomyomas. A, Sagittal transvaginalsonogram in a 30-year-old woman with a history of menometrorrhagia shows an indistinct endometrial echo complex with variable thickness; a cyst is shown adjacent to it (arrow). Sonohysterography was performed for further evaluation of these findings. B, Sagittal image from the sonohysterogram reveals an intracavitary mass containing a cystic focus (arrow). The echo texture of this mass, unlike an endometrial polyp, is similar to that of the myometrium. No endometrial abnormality was seen. C, Transvaginal sonogram in a 39-year-old woman with menorrhagia shows a large prolapsing adenomyoma distending the cervical canal (arrow). The echo texture of the mass is similar to that of the myometrium; it is, therefore, sonographically indistinguishable from a myoma. The arrowhead points to the posterior vaginal wall.

Cystic adenomyoma in a 37-year-old woman with a history of infertility. A, Multiplanar display from 3D TVS of the uterus shows a cystic mass within the right side of the uterine corpus containing low-level echoes. The bottom left image is a coronal plane through the endometrial cavity showing 2 normal cornua. Top left, axial; top right, sagittal; bottom left, coronal. B, Axial T1-weighted gradient echo opposed phase MRI (TR, 225 milliseconds; TE, 2 milliseconds) shows a hyperintense lesion within the myometrium. Lack of a chemical shift artifact around the lesion confirms the absence of fat within. C, Axial T2-weighted MRI (TR, 4000 milliseconds; TE, 100 milliseconds) image shows an intermediate to hyperintense signal in the cystic mass (arrow), showing shading, consistent with chronic hemorrhage.

Multiple fibroids and diffuse adenomyosis in a 50-year-old woman. A, Sagittal transabdominal sonogram shows a bulky uterus due to multiple fibroids. The endometrial cavity is distorted by the presence of fibroids (arrows). B, Sagittal T2-weighted MRI shows diffuse adenomyosis with marked thickening of the junctional zone (arrow) and the presence of multiple fibroids (arrowheads). In the presence of large multiple fibroids, diagnosing adenomyosis on sonography can be a difficult task.

Ultrasound of the pelvis showed left ovarian cystic lesion with internal echoes and two hyperechogenic areas inside corresponding to hemorrhagic content of the cyst. C: Axial fat sat MRI showed hyperintense lesion at left ovary. D: The lesion showed drop of SI at T2WI MRI which is pathognomonic of endometrioma. E, F: Sagittal and coronal T2WI MRI showed low SI of the lesion which is pathologically proved endometrioma by laparoscopic examination and biopsy.

Solid fibrotic thickening of the uterosacral ligament in a 40-year-old woman with endometriosis and pelvic pain. (a) Axial T2-weighted MR image shows low-signal-intensity, mass like thickening of the proximal right uterosacral ligament (arrows). The normal-appearing sacral portion of the ligament (arrowheads) is also depicted. (b) Sagittal T2-weighted MR image shows band like fibrotic adhesions above the ligament (arrows) and shading within the superior right ovarian endometriomas (arrowheads).

Endometriosis of the vesicouterinepouch in a 27-year-old woman with chronicpelvic pain. Sagittal T2-weighted (a), sagittal fat-suppressed T1-weighted (b), and oblique coronal T2-weighted (c) MR images depict irregular thickening of the upper external aspect of the bladder wall (arrowheads in a, arrows in c) that partially obliterates the vesicouterine recesses. Tiny bloody foci (arrow in b) are also seen, adding specificity to the finding.

Endometriotic involvement of the vesicovaginal septum in a 37-year-old woman who had undergone hysterectomy and presented with chronic dysuria. US showed a focal mass bulging into the posterior vesical wall. (a) Sagittal T2-weighted MR image shows a hypointense nodule (arrows) in the vesicovaginal septum. (b) On an axial fat-suppressed T1-weighted MR image, the lesion (arrowhead) has high signal intensity, which did not decrease on subsequent images. This finding indicates proteinaceous or bloody content and causes the lesion to resemble an endometrioma.

Intrinsic bladder endometriosis in a22-year-old woman who had undergone a cesarean section and presented with cyclic voiding symptoms but no hematuria. (a) Axial T2-weighted MR image shows hypointense irregular focal wall thickening (arrow) on the left posterolateral aspect of the bladder. Note the relative sparing of the perivesical fat (*) and the absence of enlarged lymph nodes. (b) Axial fat-suppressed T1-weighted MR image reveals that the area of wall thickening contains small intermingled hyperintense foci (arrow), a finding that indicates bloody content and that was crucial for differentiating between endometriosis and cancer. The patient underwent cystoscopy to exclude bladder cancer, and the tentative diagnosis of intrinsic bladder endometriosis was confirmed.

Bladder endometriosis with urethral involvement in a 31-year-old woman. (a, b) Sagittal T2-weighted (a) and fat-suppressed T1-weighted (b) MR images obtained during the patient’s menstrual period show massive irregular thickening of the anteroinferior bladder wall (arrow in a) that extends to the vesical trigone and the upper urethra and is associated with tiny interspersed bloody foci (arrowhead in b), findings that are consistent with a diagnosis of bladder endometriosis. Note the smooth outer contour of the bladder wall, as well as the normal-appearing prevesical fat (arrowheads in a). Such massive focal wall thickening with no signs of extravesical extension or perivesical fat stranding makes a diagnosis of bladder cancer less likely. (c) Axial T2-weighted MR image shows irregular hypointense thickening on the anteriorcontour of the urethra (*), a finding that indicates endometriotic involvement by direct extension from the bladder lesion.

Bladder endometriosis with ureteral involvement in a 33-year-old woman who presented with cyclic dysuria and pelvic pain, but no signs of hematuria or weight loss. (a) Axial T2-weighted MR image reveals hypointense irregular focal thickening located in the left posterolateral aspect of the bladder wall (arrows) and extending into the perivesical fat (arrowheads). (b) Sagittal T2-weighted MR image shows the perivesical and bladder wall thickening (arrow), as well as upstream ureteral dilatation (arrowheads). (c) Oblique coronal T2-weighted MR image shows an infiltrating lesion (*) encasing the lower third of the ureter (arrows). (d) Three-dimensional contrast-enhanced coronal reformatted fat-suppressed T1-weighted MR image shows a dilated left ureter (solid arrows) and a deep infiltrating endometriotic lesion involving the wall of the bladder (B) and the lower third of the ureter (arrowheads). There is also a hyperintense component in the bladder submucosa (open arrow), a finding that indicates bloody content. C = cervix, U = uterus.

Solid endometriosis of the bladder and right round ligament in a 40-year-old woman. (a, b) Sagittal (a) and axial (b) T2-weighted MR images show a poorly marginated, low-signal-intensity mass (arrowheads) in the right posterior bladder wall that extends posteriorly, obliterating the vesicouterine pouch. Intralesional 1–4-mm high-signal-intensity foci (arrows in a) represent ectopic endometrial glands. The right round ligament is thickened (arrows in b) as it courses inferiorly toward the canal of Nuck. (c, d) Axial T1-weighted gradient-echo fat-suppressed MR images obtained before (c) and after (d) the administration of a gadolinium-based contrast material show T1 hyperintensity in some of the endometrial glands within the posterior bladder lesion (arrow in c) and solid enhancement of both the bladder mass (arrowheads in d) and the thickened round ligament (arrow in d).

Ureteral endometriosis in a 31-year-old woman with chronic pelvic pain and left hydronephrosis.(a) Axial T2-weighted MR image shows hypointense irregular and spiculated thickening and stranding of the perivesical fat on the left side (arrows). The ureter (arrowhead) traverses the involved area, a finding that is suggestive of infiltrating endometriosis. (b) Para sagittal T2-weighted MR image reveals moderate dilatation of the left ureter (arrowheads) to the level of the insertion of the ipsilateral uterosacral ligament (arrow), which is irregular and thickened, indicating associated deep endometriosis. (c) Fat-suppressed T1-weighted MR image shows a cystic lesion (arrow) whose high signal intensity indicates proteinaceous or bloody content. The lesion resembles an endometrioma located medial to hypointense thickening of the perivesical fat. (d) Three-dimensional contrast-enhanced fat-suppressed excretory phase T1-weighted MR urogram shows the repercussions of the findings in a–c to the urinary system. The left ureter is severely narrowed in its lower third (arrowhead), with associated upstream dilatation up to the renal pelvis (*).The lesion (arrow) is seen adjacent to the narrowed ureter and represents an endometrioma.

Endometriotic involvement ofthe retrocervical area in a 33-year-old woman with dyspareunia. At earlier MR imaging examinations, an endometrial implant was seen in this area. (a) Sagittal T2-weighted MR image shows an irregular, solid, nodular hypointense mass (arrow) slightly inferior to the uterine torus, with intermingled hyperintense foci (arrowhead). (b) On an axial fat-suppressed T1-weighted MR image, the intermingled foci (arrow) remain hyperintense, a findingthat indicates bloody content.

Solid invasive endometriosis of the rectosigmoid colon in a 40-year-old woman. (a) Lateral image from a double-contrast barium examination shows circumferential narrowing of the rectosigmoid colon, with mass effect, speculation, and pleating of the anterior margin (arrow). (b) Sagittal T2-weighted fast spin-echo MR image shows extraluminal findings suggestive of solid invasive endometriosis. The mushroom cap sign represents the low-signal-intensity core of fibrotic endometriosis and hypertrophic muscularis propria (*) capped by high-signal-intensity mucosa (straight arrows). Invasion of the serosal surface of the uterus and obliteration of the cul-de-sac (arrowheads) are seen, with high-signal-intensity 1–3-mm foci (curved arrow) representing ectopic endometrial glands.

Endometriotic involvement of the uterine ligaments in a 31-year-old woman with chronic pelvic pain and a known history of endometriosis. Axial gadolinium-enhanced fat-suppressed late-phase T1-weighted MR image shows homogeneous late enhancement of thickened round uterine ligaments (arrows) due to involvement of their uterine insertions by an endometriotic lesion.

Endometriotic involvement of the posterior pelvic compartment in a 29-year-old woman with hypermenorrhea, dyspareunia, and dysmenorrhea. Earlier MR imaging showed retrocervical endometriosis with fibrotic obliteration of the rectovaginal pouch. Sagittal (a) and axial (b) T2-weighted MR images show an irregular hypointense mass (arrowhead) that extends from the posterior cervix inferiorly to the vaginal fornix. Note the presence of a subserous leiomyoma in the anterior uterine wall (black arrow in a), focal adenomyosis in the corporal anterior uterine wall (white arrow), and a right follicular ovarian cyst (* in b).

Endometriotic involvement of the uterosacral ligaments in a 31-year-old woman who presented with pelvic pain, dyspareunia, and painful defecation. Earlier MR imaging showed involvement of these structures. (a, b) Coronal (a) and axial (b) T2-weighted images show hypointense irregular spiculated nodular thickening of the right uterosacral ligament (white arrow in a), with minimal intermingled hyperintense foci. These findings create an arciform abnormality (arrowheads in b) that extends to the anterior rectal wall, where thereis focal parietal thickening (black arrow). (c) Axial fat-suppressed T1-weighted MR image shows hyperintense foci (solid arrows), a finding that indicates bloody content. Open arrow indicates focal parietal thickening. (d) Laparoscopic image obtained in a different patientshows involvement of the uterosacral ligaments (arrows).

Isolated endometriotic involvement of the vagina in a 38-year-old woman who had undergone hysterectomy and presented with dyspareunia and chronic pelvic pain. Earlier MR imaging showed vaginal involvement. (a) Axial T2-weighted MR image shows a hypointense nodule (arrows) in the posterior upper third of the vagina. (b) Axial T1-weighted MR image shows minimal intermingled hyperintense foci (arrowheads), a finding that indicates bloody content.

Endometriotic involvement of the ischioanal fossa in a 32-year-old woman who presented with right hip pain. The patient had no history of perineal surgery. (a) Axial T2-weighted MR image shows solid, predominantly glandular endometriosis (arrows) in the ischioanal fossa located close to the right ischiatic tuberosity and involving the internal obturator muscle and anal sphincter. (b, c) Axial T1-weighted (b) and fat-saturated T1-weighted (c) MR images show intermingled hyperintense foci (arrow), a finding that indicates bloody content. Arrowhead in b indicates cortical sclerosis. (d) Coronal T1-weighted MR image shows significant bone reaction (cortical sclerosis) in the medial aspect of the right ischiatic tuberosity (arrowhead).

Sigmoid endometriosis in a 30-year-old woman who experienced painful defecation and hematochezia during her menstrual period. (a, b) Sagittal (a) and coronal (b) T2- weighted MR images obtained after the administration of a saline rectal enema and intravaginal aqueous gel show hypointense nodular thickening of the sigmoid wall (arrows) adhering to the posterior uterine serosa (arrowhead in a). (c) Sagittal gadolinium-enhanced fat suppressed late-phase T1-weighted MR image shows enhancement of the lesion (arrow). The findings in a–c are consistent with a diagnosis of sigmoid endometriosis.

Cyclic sciatica in a 27-year-old woman. Earlier MR imaging showed sciatic nerve involvement. (a) Axial MR image showshypointense irregular spiculated soft-tissuethickening (arrows) in the left sciatic notch.(b) Axial fat-suppressed T1-weighted MR image shows minimal intermingled hyperintense foci (arrows), a finding that indicates bloody content. (c) Axial gadolinium-enhanced fat suppressed late-phase T1-weighted MR image shows enhancement of the lesion (arrows).

Deep endometriosis at various sites in a 35-year-old woman who presented with chronic pelvic pain, infertility, and dysuria. Earlier MR imaging showed endometriotic involvement of the urinary bladder, rectovaginal septum, and retrocervical area. (a, b) Sagittal (a) and axial (b) T2-weighted MR images demonstrate hypointense focal thickening of theright posterolateral wall of the bladder (blackarrow) with punctate intermingled bleeding,along with an extraperitoneal, irregular hypointense nodule (white arrows) that mainly involves the retrocervical area and the upper portion of the rectovaginal septum. (c) Axial fat-saturated T1-weighted MR image shows the nodule. Arrowhead = punctate bleeding.

37 year old woman with a history of dysmenorrhea. Images: (a) coronal T2-weighted and (b) axial T1 with fat suppression and gadolinium. Enlarged right ovary with multiple cysts (*) and an endometrioma with intermediate signal on T2 and hyperintense on T1 with fat suppression and gadolinium (à black).

Relatively hyperechoic SOL at right ovary. B: MRI (axial T1WI) shows hyperintense content of the right ovary. C: Axial T2WI shows low SI of the cyst of the right ovary (shading sign). D: Axial T1WI with fat sat shows hyperintense cystic right ovarian lesion (hemorrhage). E, F: MRI (sagittal and coronal T2WI) revealed low SI of right ovarian lesion.

37 year old woman. Infertility study. Images: (a) Sagittal T2-weighted and (b) coronal T2 and (c) axial T2. Bilateral ovarian endometrioma and left hydrosalpinx (à white).

Endometrioma at ultrasound and laparoscopy.

T2- and fat sat T1-images of an endometrioma with hypointensity on T2 (shading), fluid-fluid levels on T2 (left) and hyperintense blood on T1WI with fat sat (right).

Endometrioma.

Endometrioma of the left ovary in a 33-year-old woman. (a, b) Axial T1-weighted in-phase (a) and opposed-phase fat-suppressed (b) gradient-echo MR images show a T1-hyperintense left ovarian lesion, a feature suggestive of endometrioma. (c) Axial T2-weighted MR image shows lower signal intensity in the endometrioma than in the adjacent normal ovarian follicles (arrows). (d, e) Diffusion-weighted MR images obtained with b values of 50 (d) and 800 (e) sec/mm2 show low to intermediate signal intensity in both the endometrioma and the normal follicles. (f) ADC map from diffusion-weighted MR imaging shows restricted diffusion in the endometrioma relative to that in the adjacent ovarian follicles.

Left ovarian endometriomas, bilateral hematosalpinges, and fibrotic solid invasive endometriosis in the posterior uterus of a 47-year-old woman with severe pelvic pain. (a) Axial T1-weighted in-phase gradient-echo MR image shows two foci of high signal intensity in the left ovary (arrow) and multiple foci of high signal intensity in the left anterior and midline posterior pelvis (arrowheads). (b) Axial opposed-phase T1-weighted fat-suppressed gradient-echo MR image shows persistent high signal intensity in all three regions, a finding that helps exclude the presence of a fat-containing mature cystic teratoma. The improved dynamic range achieved with fat suppression facilitates visualization of a subcentimeter endometrioma of the anterior left ovary (arrow). (c) Axial T2-weighted fast spin-echo MR image shows low signal intensity within the left ovarian endometriomas (solid arrow) and lesser degrees of T2 signal hypointensity within the dependent portions of the loculi in the left anterior and midline posterior pelvis (arrowheads). The posterior uterus is markedly thickened with low-signal-intensity soft tissue (F) containing scattered 2–4-mm foci of high signal intensity (open arrows). Although the tissue has the appearance of adenomyosis, it is separated from the posterior junctional zone (JZ). These findings are suggestive of fibrotic endometriosis. (d, e) Sagittal (d) and coronal fat-suppressed (e) T2-weighted MR images show dilatation of the right and left fallopian tubes, respectively (arrows). In d, extension of fibrotic endometriosis (F) into the posterior uterus is seen. The patient later underwent hysterectomy and bilateral salpingo-oophorectomy, at which the MR imaging findings were confirmed.

Right ovarian endometrioma in a 35-year-old woman that might have been misinterpreted as a mature cystic teratoma with reliance on short inversion time inversion-recovery (STIR) imaging alone to detect Intralesional fat. (a) Axial T1-weighted spin-echo MR image shows a high-signal-intensity mass (arrow) within the right adnexa. (b) Coronal STIR MR image shows that the mass (arrow) has low signal intensity similar to that of suppressed fat. (c) Axial fat-suppressed gradient-echo MR image shows high signal intensity of the mass (arrow), a finding that helps confirm that it is not composed of fat. The low signal intensity of the mass on the STIR image could be secondary to either T1- or T2-shortening effects but cannot be considered indicative of fat content. To avoid this pitfall of STIR MR imaging of the female pelvis, MR systems capable of performing chemical-shift fat suppression should be used.

Bilateral endometriomas, solid endometriosis of the posterior uterus, and left-sided peritoneal inclusion cyst in a 43-year-old woman. (a, b) Axial T1-weighted in-phase (a) and fat-suppressed opposed-phase (b) gradient-echo MR images show bilateral hyperintense adnexal lesions (arrows) that retain high signal intensity with fat suppression. A peritoneal inclusion cyst (*) is also shown posterior to the uterus (U). Susceptibility artifacts anterior to the rectus muscles (arrowheads in a) indicate that the patient has undergone a previous surgical procedure. (c) Axial T2-weighted MR image shows shading within the bilateral endometriomas (straight arrows). The normal endometrial complex and junctional zone are shown in the anterior uterus (arrowheads). The posterior uterus is markedly enlarged by poorly marginated soft tissue (E) with low T2 signal intensity and scattered internal 1–2-mm foci of higher signal intensity (curved arrow) representing infiltration of solid endometriosis into the uterine wall. Loculated fluid posterior to the left ovary represents the peritoneal inclusion cyst

53 year old woman. Background history of hysterectomy with cyclic hematuria. Images: (a) Sagittal T2-weighted, (b) coronal T2, (c) axial T2 and (d) Cystoscopy. On the bladder roof at left (à white) a mass of 1.5 x 1.1 cm can be seen, this is an intermediate T2 signal with undefined borders infiltrating the bladder wall, being located in the bladder lumen (à black). In the cystoscopy can be observed, in left top wall, a sessile uplifted lesion of approximately1 cm. The remainder of the bladder mucosa appears normal and without lesions.

31 year old woman with a history of dysmenorrhea. Images: (a) coronal T2-weighted (b) axial T1 and (c) coronal T2. Left ovarian endometrioma (à white) of 9.3 x 7.6 cm attached tothe uterine torus by a deep endometriosis foci (à white curved). Infiltration of the distal ureter by fibrotic endometrial implant (à) that is associated with hydroureteronephrosis (*).

46 year old woman. Nodule of the abdominal wall under study. Images: (a) sagittal T2-weighted and (b) axial T1 and (c) axial T1 with fat-suppression and gadolinium. Solid node 20 x 12mm on abdominal wall at the hypogastrium level lateralized to the left, heterogeneous signal (with hypointense focus) on T2 and isointense on T1 (white circle) with discrete and homogeneous enhancement with contrast. External marker (*). Pathology compatible with endometriosis foci.

33 year old woman. Palpable nodule in relation to episiotomy. Images: (a) axial T2-weighted and (b) axial T1. Lobulated nodule in the right perianal region on episiotomy site (à white). Slightly hyperintense on T1 and isointense on T2.

Transvaginal US revealed abnormal increase in thickness of myometrium in a retroverted uterus. B: MRI (sagittal T2WI) shows retroverted uterus with abnormal increase thickness in junctional zone (10 mm) and diffuse abnormal high T2 SI of myometrium abnormal stromal glands. C: MRI (coronal T2WI) shows the same findings as image B. Examination.

Decidualized endometriosis in a 36-year-old woman in the 12th week of pregnancy. (a, b) Sagittal T2-weighted fast spin-echo MR images show an intrauterine gestational sac, a focal contraction (C) of the posterior myometrium, and an anterior placenta (P). The bilobed low-signal-intensity mass above the uterus represents an endometrioma (E). Mural nodules with higher signal intensity within the endometrioma (arrows in b) represent decidualized endometriosis. (c, d) Axial T1-weighted fat-suppressed (c) and T2-weighted fast spin-echo (d) MR images show the typical signal intensity of an endometrioma, with T1 hyperintensity and T2 shading, and the higher T2 signal intensity of decidualized endometriosis (arrow in d).

Hematometrocolpos, hematosalpinx, and endometriomas in a 15-year-old girl with an obstructing transverse vaginal septum. (a) Coronal T2-weighted fat-suppressed MR image shows dilatation of the endometrium (E), endocervix (C), and proximal vagina (V) due to a transverse vaginal septum (not shown). (b, c) Axial T1-weighted fat-suppressed (b) and T2-weighted fast spin-echo (c) MR images obtained at the level of the uterus show the distended vaginal canal (V) and segments of a dilated right fallopian tube (arrow). These structures have similar high T1 signal intensity and intermediate T2 signal intensity. (d) Axial T1-weighted fat-suppressed MR image obtained at the level of the right ovary shows multiple subcentimeter high-signal-intensity endometriomas (arrows), findings confirmed at resection of the vaginal septum.

Endometrioid cystadenocarcinoma of the left ovary in a 51-year-old woman with long-standing endometriosis. (a) Axial T2-weighted MR image shows a cystic pelvic mass that also contains solid soft tissue (arrow). The signal of the cystic component was slightly hypointense to that of the bladder (not shown). (b, c) Axial T1-weighted fat-suppressed gradient-echo MR images obtained before (b) and after (c) the administration of a gadolinium-based contrast material show that the cystic component has T1 hyperintensity, a finding suggestive of proteinaceous or hemorrhagic content. The signal intensity of the solid component of the mass, relative to that of the cystic portion, is lower in b and higher in c. (d) MR image obtained by subtracting the unenhanced image dataset from the contrast-enhanced image dataset facilitates the detection of enhancing tissue (arrow) by increasing the dynamic range (61) and eliminating the high signal intensity of nonenhancing hemorrhagic and proteinaceous tissue. (e, f) Unenhanced T1-weighted fat-suppressed (e) and gadolinium-enhanced subtraction (f) MR images obtained at a lower level show additional enhancing nodular components (arrows in f) in the tumor. A 1-cm right ovarian endometrioma (arrow in e) is also seen.

Endometriosis involving appendix. A, Mucocele formation in 38-year-old woman with chronic right lower quadrant pain. CT image obtained with oral and IV contrast material shows lobulated, low attenuation cystic mass (arrow) in right lower quadrant. Surgery and pathology confirmed mucocele secondary to endometriotic implant with obstruction of appendix. B, Acute appendicitis in 24-year-old woman with right lower quadrant pain and fever. CT image obtained with oral and IV contrast material shows dilated, fluid-filled appendix (black arrow) compatible with acute appendicitis. Soft-tissue density at base of appendix (white arrow) was confirmed as endometriotic implant at pathology.

Infected endometrioma in 38-year-old woman with pelvic pain and fever of unknown source. A, CT image obtained initially shows large pelvic mass (arrows) that is uniformly low attenuation. Ovarian origin of mass was suspected. B, Transvaginal sonogram confirms that mass originates from right ovary. There were homogeneous low-level echoes and diagnosis of endometrioma was made. No other source of patient’s fever was identified and she was taken to surgery for further evaluation of mass. Intraoperatively, 16 × 12 cm mass was densely adherent to adjacent structures. Cyst puncture yielded 800 mL of foul-smelling, purulent contents. Pathology confirmed endometrioma with superimposed acute and chronic inflammation and salpingitis. Cursors delineate mass.

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