Questions to be answered by MRI in the planning and evaluation of fibroid embolization

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1 Questions to be answered by MRI in the planning and evaluation of fibroid embolization Award: Magna Cum Laude Poster No.: C-0076 Congress: ECR 2015 Type: Educational Exhibit Authors: C. Maciel, A. M. Madureira, P. M. Vilares Morgado ; Porto/PT, Matosinhos/PT Keywords: Ischemia / Infarction, Embolisation, Diagnostic procedure, MRAngiography, MR, Interventional vascular, Genital / Reproductive system female DOI: /ecr2015/C-0076 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 77

2 Learning objectives -To review the MR imaging features of the most common coexisting conditions and alternative diagnosis to uterine fibroids. -To discuss the relevant MR imaging findings that may influence the planning of uterine artery embolization (UAE), namely the location, size and enhancement of fibroids. -To highlight the merits of performing MR angiography of the pelvic vasculature prior to UAE, with emphasis on variant pelvic arterial anatomy relevant to perform UAE. -To discuss the MRI assessment after UAE, including evaluation of fibroid infarction, changes in fibroid size and location, fibroid regrowth and recurrence. Uterine and fibroid volumes calculation is exemplified. Background -UAE is an angiographic procedure, based on super-selective catheterization and target embolization. It is an effective, safe and minimally invasive treatment for symptomatic uterine fibroids. -Pre-procedural MR imaging has proven clinical utility in determining the appropriate use of UAE and predicting outcomes. -There is emerging evidence for the use of MRA for planning and improving operative performance of UAE. MRA allows pretreatment assessment of the normal and variant pelvic arterial anatomy. Additionally, MRA may depicts enlarged ovarian arteries possibly supplying uterine fibroids [1]. MRA is also useful in the prediction of the optimal projection angle to demonstrate uterine artery origin at subsequent angiography, reducing radiation dose, fluoroscopy time, and volume of contrast medium used [2]. Page 2 of 77

3 -Post-procedural MR imaging is routinely used to evaluate effectiveness of UAE and to identify post embolization complications. Findings and procedure details 1.DIFFERENTIAL DIAGNOSIS: IS IT A FIBROID? Adenomyosis, endometriosis, solid adnexal masses, myometrial contractions, musculoskeletal and genitourinary pathology and occasionally uterine leiomyosarcomas may be ''incidental'' MRI findings in patients being assessed for fibroid embolization, or they may provide an alternative explanation for the patient's symptoms [3]. Some of these conditions may preclude UAE or influence the outcome. ADENOMYOSIS -It is the intrauterine counterpart to endometriosis - abnormal implantation of endometrial cells in the myometrium. -Can be focal or diffuse;occasionally mimics fibroids, although the two conditions can coexist. (Fig. 1 on page 39) Key imaging findings: unlike fibroids, adenomyosis generally lacks distinct margins and exerts no mass effect. Instead of displacing or distorting the adjacent endometrium, adenomiosis abuts the endometrium without displacement. Adenomyosis signal intensity approximates junctional zone hypointensity with possible intralesional T1 and/or T2 hyperintensities. A junctional zone measurement of 12 mm or greater confirms the diagnosis of adenomyosis; between 8 and 12 mm is indeterminate [4]. Practical relevance to UAE: coexistent adenomyosis should be noted before performing UAE, and patients should be informed of a more variable outcome [5]. Page 3 of 77

4 Fig. 1: Coexistence of a fibroid and adenomyosis in a 54-year-old woman presenting for preembolization evaluation. The patient was referred with an ultrasound examination reporting the presence of a large intramural fibroid in the anterior uterine wall. (a)sagittal T2-weighted fast SE image shows diffuse thickening of the junctional zone, more prominent anteriorly, consistent with diffuse adenomyosis (Ad). (b)the corresponding contrast-enhanced fatsaturated T1-weighted fast SE image shows diffuse heterogeneous enhancement throughout the myometrium without evidence of an underlying focal lesion besides a small intramural fibroid (F). The ultrasound features of adenomyosis can overlap with those of uterine fibroids resulting in misdiagnosis as in this case and additional imaging with MR is problem-solving. References: Radiology, Hospital de São João - Porto/PT ADNEXAL MASSES -The differential diagnosis between pedunculated fibroids and solid adnexal masses can be challenging whenever normal ovaries are not cleary depicted. Page 4 of 77

5 Key imaging findings: ovarian fibromas and Brenner tumors are benign ovarian neoplasms that have a large fibrous component and can have signal intensity similar to that of a pedunculated fibroid. MR imaging can show fibromas and Brenner tumors surrounded by ovarian stroma and follicles, thus establishing the ovarian origin of the mass and allowing exclusion of a diagnosis of fibroid (Fig. 2 on page 39).On the other hand, if the bridging vessel sign is present, the diagnosis of fibroid can be suggested, as continuity of the mass with the adjacent myometrium is demonstrated [6] (Fig. 3 on page 40). Practical relevance to UAE: complex masses suspicious for ovarian malignancy need to be diagnosed before UAE [7]. The presence of benign ovarian masses it is not a contraindication to UAE (Fig. 4 on page 41 Fig. 5 on page 42 Fig. 6 on page 43). Fig. 2: Ovarian fibroma simulating pedunculated subserosal fibroid in a 34-yearold woman. (a) Sagittal T2-weighted fast SE image shows a large solid lesion with a small peripheral cystic component (arrow), located adjacent to the uterine cervix. This lesion is hypointense compared to the myometrium. A small quantity of free fluid in pouch of Douglas is present (asterisk).(b,c) Contiguous sagittal contrast-enhanced T1-weighted fast SE images reveal the eccentrically located Page 5 of 77

6 ipsilateral ovary (circle) in the periphery of the fibroma and a small peripheral cystic component (arrow). The fibroma enhances less than the myometrium. An innacurate preoperative diagnosis of a pedunculated subserosal fibroid with cystic degeneration was made; the diagnosis of an ovarian fibroma was pathologically proved. OvF-ovarian fibroma. References: Radiology, Hospital de São João - Porto/PT Fig. 3: Pedunculated subserosal fibroid simulating an adnexal mass in a 40year-old woman presenting for preembolization evaluation. (a) Sagittal T2weighted fast SE image shows a large hypointense lesion adjacent to the uterus. Sagittal contrast-enhanced T1-weighted fast SE MR images (b,c) reveal a stalk (arrow) connecting the lesion to the uterine fundus and multiple vessels (circle) between the uterus and the lesion, appearing as curvilinear tortuous flow voids (the bridging vessel sign), confirming the diagnosis of a fibroid, thereby allowing exclusion of an adnexal mass. References: Radiology, Hospital de São João - Porto/PT Page 6 of 77

7 Fig. 6: Coexistence of fibroids and dermoid cyst in a 33-year-old woman presenting for preembolization evaluation. Saggital contrast-enhanced fat-saturated T1-weighted fast SE images, before (d) and after (e) UAE, demonstrated the presence of macroscopic fat (asterisk) and an absence of enhancement, allowing the diagnosis of a dermoid cyst (D). Note the complete lack of enhancement of the fibroid (F) after UAE, in keeping with successful embolization. The diagnosis of dermoid cyst (mature cystic teratoma) was pathologically proved. References: Radiology, Hospital de São João - Porto/PT MYOMETRIAL CONTRACTIONS -Myometrial contractions may occasionally simulate a fibroid (or focal adenomyosis) at MR imaging. Page 7 of 77

8 Key imaging findings: they can appear as transient hypointense T2-weighted masses. The key to this diagnosis is changeability. Each sequence should be checked for interval change or resolution to confirm a myometrial contraction [4]. UTERINE LEIOMYOSARCOMA: WHAT ARE THE ALARM SIGNS? -The imaging diagnosis of uterine leiomyosarcoma (LMS) in the absence of metastatic disease remains difficult. Key imaging findings: rapid growth is often considered a suggestive feature of LMS. Continued growth after embolization is an important additional sign of possible malignancy [8]. Imaging features that should generally raise concern for LMS include a large mass with a bizarre appearance that includes marked cystic-appearing changes and areas of high signal on T1-weighted imaging resulting from hemorrhage [5]. Practical relevance to UAE: the described imaging appearances should prompt consideration of surgical management, biopsy before UAE, or short-interval follow-up imaging; Known or suspected gynecologic malignancy is an absolute contraindication to UAE [7]. -Although it is important to remain cognizant of LMS, in the majority of cases where LMS is in the differential diagnosis, histologic diagnosis usually reveals a bening fibroid [5] (Fig. 7 on page 44,Fig. 8 on page 45). Page 8 of 77

9 Fig. 7: Suspicion of uterine leiomyosarcoma in a 31 year-old-woman with a history of two previous UAE, the most recent 5 years prior to current MR examination, presenting with epigastric pain, anorexia and enlarging myometrial mass despite previous embolizations. Sagittal (a) and coronal (b) T2-weighted fast SE images show a huge uterus containing a heterogeneous mass (arrows) arising from the fundus, with necrotic/cystic areas (C). The remarkable increase in size and the presence of necrotic/cystic areas, did not allowed ruling out the possibility of a leiomyossarcoma. At pathology, it was in fact a leiomyoma. Several newely developed fibroids (F) were identified, in keeping with recurrence. References: Radiology, Hospital de São João - Porto/PT 2.INTRAUTERINE DEVICES/SYSTEMS: IS IT SAFE TO PERFORM UAE? -Concerning to MR safety issues: Page 9 of 77

10 Copper-containing intrauterine devices (Cu-IUD) are MR safe for women scanned on a 1.5-T system. Some models of Cu-IUD are classified as MR conditional and do not pose known hazards, provided that the MRI is of a maximum of 3.0 T. The Mirena intrauterine system (IUS) is a hormone-releasing device that contains levonorgestrel. This T-shaped device is made entirely from nonmetallic materials. It is safe for patients undergoing MR procedures using MR systems operating at all static magnetic field strengths. Detailed information about a specific IUD/IUS can be found on [9]. -Concerning to the risk of infectious complications after UAE: It appear not to be increased in patients with an IUD in situ [10]. Practical relevance to UAE: presence of an IUD/IUS is not considered a contraindication for UAE [10] (Fig. 9 on page 46). Page 10 of 77

11 Fig. 9: UAE in a 40-year-old patient having a copper-containing intrauterine device (IUD). (a) Axial T2-weighted fast SE image clearly depicts a T-shaped IUD as a no-signal zone inside the uterine cavity, without susceptibility artifacts. (b) Uterine angiogram obtained before embolization shows a large fibroid (F) projecting from the left side of the uterus. The IUD is seen. References: Radiology, Hospital de São João - Porto/PT 3.SIZE: DOES IT MATTER? -Several studies suggest that UAE outcomes in large fibroid tumors are comparable to those in small tumors, without an increased risk of significant complications [11] ( Fig. 10 on page 47). Practical relevance to UAE: many interventionists maintain a threshold for embolization of cm for the longest fibroid axis. Above this, the postembolization volume may still result in bulk symptoms, and the necrosis from a large fibroid may result in a prolonged postembolization syndrome [3]. Page 11 of 77

12 Fig. 10: Technically successful UAE in a 33-year-old patient presenting with a huge fibroid measuring 16,5 cm in long axis. (a)sagittal T2-W fast SE image before UAE shows a huge fibroid (F). (b)sagittal T1-W contrast-enhanced fatsaturated fast SE image, obtained three months after UAE, shows a still bulky fibroid (F), with complete lack of enhancement, consistent with successful embolization. An additional shrinkage of fibroid within the next months is expected to occur. References: Radiology, Hospital de São João - Porto/PT 4.ENHANCEMENT: DOES IT MATTER? -Enhancement of fibroids depends on their vascularity. Key imaging findings:gadolinium-enhanced T1-weighted fat-saturated sequences are essential to demonstrating fibroid vascularity. Vascularity varies and enhancement Page 12 of 77

13 ranges from virtually absent (avascular) to marked enhancement (hypervascular) compared with the adjacent myometrium [4]. -Cellular leiomyomas, which are composed of compact smooth muscles cells with little or no collagen, can have relatively increased T2-weighted signal intensity and tend to have marked homogeneous enhancement on contrast-enhanced images [6] (Fig. 11 on page 48). Practical relevance to UAE: Fibroids that have already infarcted are unlikely to show volume reduction with UAE, and therefore, improvement of symptoms is less likely [6]. Nikolaidis et al. reported a prevalence of nonviable fibroids of 20% with gadolinium-enhanced MRI; 6% of patients had nonviable dominant fibroids [12]. Fibroids with high T2 signal and gadolinium enhancement tend to respond better to UAE, whereas fibroids with increased T1 signal and less gadolinium uptake may not shrink significantly following UAE. Persistent enhancement of fibroids after UAE is a sign of treatment failure that may need additional treatment including repeated UAE or surgery [13]. Page 13 of 77

14 Fig. 11: Hypervascular fibroids in 33-year-old woman presenting for preembolization evaluation. Sagittal (a) and axial (d) T2-weighted fast SE images show two intramural fibroids slightly hyperintense (reflecting high cellularity and relatively less stroma). On T1-weighted fast SE image (c) the fibroids are isointense with the myometrium. After gadolinium administration (b) both fibroids show remarkable contrast enhancement, enhancing more than the myometrium, according to their hypervascular nature. These findings are consistent with celullar fibroids. References: Radiology, Hospital de São João - Porto/PT Page 14 of 77

15 Fig. 12: Self-infarcted fibroid in a 33-year-old woman presenting for preembolization evaluation. (a) Sagittal T2-weighted fast SE image shows several fibroids (F1,F2,F3). After gadolinium administration (b) F1 shows complete lack of enhancement, consistent with non viable fibroid. F2 is hypovascular, showing a relative lack of enhancement. F3 presents the most common enhacement pattern - slight hypovascular compared with the adjacent myometrium. The endometrial canal (arrow) can be seen sandwiched between the fibroids. References: Radiology, Hospital de São João - Porto/PT 5.LOCATION: DOES IT MATTER? -Although all fibroid locations are eligble for embolization [7] certain anatomic fibroid subtypes deserve special consideration. Page 15 of 77

16 Submucosal location: submucosal and intramural fibroids that have a large submucosal component may be at increased risk for post-uae sloughing or expulsion, which can result in significant pain, bleeding, infection, and prolonged vaginal discharge [14] (Fig. 13 on page 50). Practical relevance to UAE: patients should be counseled about the risks associated with this class of fibroids. Pedunculated subserosal fibroids: this fibroid subtype, particularly when there is a narrow attachment to the uterus, has been suggested as a contraindication to UAE because of the potential risk of detachment. More recent studies found no instances of fibroid detachment in patients with pedunculated subserosal fibroids, with clinical outcomes similar to those in patients with other fibroid subtypes [15]. Cervical fibroids: are uncomon and account for 5% (range %) of uterine fibroids. In comparison with other fibroid subtypes, cervical fibroids appear to be more resistant to complete infarction after UAE. Placement of the microcatheter tip beyond the cervicovaginal branch of the uterine artery was suggested as a possible cause of this phenomenon. Incomplete infarction may be a function of additional or alternative blood supply to the cervix. Cervical and vaginal branches of the uterine arteries supply the cervix and upper vagina, but there is considerable anatomic variation and anastomoses in the uterine cervix with vaginal and middle hemorrhoidal arteries, which might explain the frequent failure of UAE [16] (Fig. 14 on page 51). 6.UTERINE AND FIBROID VOLUMES ASSESSMENT: HOW TO CALCULATE? -Calculation of uterine and fibroid volume is modeled on the volume of a prolate ellipsoid. Mathematically, the volume of a prolate ellipsoid is calculated using the formula #/6 x length width thickness. -For the purposes of calculating uterine or fibroid volume the simplified formula 0.5 length width thickness is used. (Fig. 15 on page 52, Fig. 16 on page 53). Practical relevance to UAE: with successful embolization, some decrease in uterine and fibroids size is expected. Uterine and fibroids volumes can be calculate before and after UAE and percentage volume reductions can then be assessed if required. Page 16 of 77

17 Fig. 15 References: Radiology, Hospital de São João - Porto/PT Page 17 of 77

18 Fig. 16 References: Radiology, Hospital de São João - Porto/PT 7. MR ANGIOGRAPHY BEFORE UAE: WHAT TO LOOK FOR? NORMAL AND VARIANT PELVIC ARTERIAL ANATOMY -MRA can detect most branches of the internal iliac artery in women, in addition to the branches points of origin. Additionally, is useful in the assessment of the threedimensional configuration of uterine arteries [17]. -The presence of uterine fibroids usually results in distortion and enlargement of the uterine arteries (Fig. 17 on page 54, Fig. 18 on page 55, Fig. 19 on page 56). Page 18 of 77

19 Fig. 17: MR angiography in a 34-year-old-woman presenting for preembolization evaluation shows a hypertrophic right uterine artery and a small caliber left uterine artery. (a) MIP image from MRA depicts a prominent right uterine artery (arrow). (b) DSA image obtained with selective right internal iliac artery catheterization confirms the MRA findings. (c) Right para-sagittal T2weighted fast SE image depicts a bulky fibroid (F). Notice the flow voids (circle) appearing as hypointense structures at the interface between the fibroid and the myometrium, in relation with dilated feeding arteries with fast flow, feeding the vascular plexus of the fibroid. Right ovary has unremarkable appearance (asterisk). References: Radiology, Hospital de São João - Porto/PT Page 19 of 77

20 Fig. 18: MR angiography in 34-year-old-woman presenting for preembolization evaluation shows a hypertrophic right uterine artery and a small caliber left uterine artery. (d) MIP image from MRA in a 38 left obliquity nicely depicts a small caliper left uterine artery (arrow). Notice that the oblique view helps identify the optimal angle for left uterine artery origin. (e) DSA image shows the corresponding angiographic projection and clear demonstration of the origin (arrow) of the left uterine artery arising from the proximal inferior gluteal artery, in accordance with the MR angiographic findings. References: Radiology, Hospital de São João - Porto/PT Page 20 of 77

21 Fig. 19: MR angiography in a 35-year-old-woman presenting for preembolization evaluation. MIP image from MRA depicts two uterine arteries of similar normal caliber (arrows). References: Radiology, Hospital de São João - Porto/PT -The anatomy of the uterine artery can be categorized by the location of the origin of the artery [19] (Fig. 20 on page 57, Fig. 21 on page 58, Fig. 22 on page 59, Fig. 23 on page 60). Page 21 of 77

22 Fig. 20: MR angiography in a 31-year-old woman presenting for preembolization evaluation with angiographic correlation. (a)anatomical diagram illustrates the uterine artery as the first branch of the inferior gluteal artery. (b)mip image from MRA depicts a type I uterine artery origin. (c)dsa obtained with selective left internal iliac artery catheterization demonstrates good correlation with MR angiography. UA- uterine artery; CI- common iliac; II- internal iliac; EI- external iliac; IL- iliolumbar; SG- superior gluteal; IG- inferior gluteal. Anatomical diagram adapted from Horton AW, Patel U, Belli AM. (2010) An unusual arterial supply to the uterus. A case report and review of anatomy-implications for uterine artery embolization. Clinical Radiology 65: References: Radiology, Hospital de São João - Porto/PT Page 22 of 77

23 Fig. 21: (a)anatomical diagram illustrates the uterine artery as the second or third branch of the inferior gluteal artery. (b)dsa image shows the uterine artery (small arrow) as the second branch of the inferior gluteal artery. The internal pudendal artery (arrow), is the first branch of the inferior gluteal artery. UAuterine artery; IP-internal pudendal. Anatomical diagram adapted from Horton AW, Patel U, Belli AM. (2010) An unusual arterial supply to the uterus. A case report and review of anatomy-implications for uterine artery embolization. Clinical Radiology 65: DSA image adapted Gomez-Jorge J, Keyoung A, Levy EB, Spies JB.Uterine artery anatomy relevant to uterine leiomyomata embolization (2003) Cardiovasc Intervent Radiol 26: References: Radiology, Hospital de São João - Porto/PT Page 23 of 77

24 Fig. 22: MR angiography in a 41-year-old woman presenting for preembolization evaluation with angiographic correlation. (a)anatomical diagram illustrates the uterine artery, the inferior gluteal and the superior gluteal arteries branching at the same level from the internal iliac artery, as a trifurcation. (b) MIP image from MRA nicely depicts trifurcation of the right internal iliac artery. (c) DSA obtained with selective internal iliac artery catheterization demonstrates good correlation with MRA. UA- uterine artery; II- internal iliac; SG- superior gluteal; IG- inferior gluteal. Anatomical diagram adapted from Horton AW, Patel U, Belli AM. (2010) An unusual arterial supply to the uterus. A case report and review of anatomyimplications for uterine artery embolization. Clinical Radiology 65: References: Radiology, Hospital de São João - Porto/PT Page 24 of 77

25 Fig. 23: MR angiography in a 35-year-old woman presenting for preembolization evaluation with angiographic correlation. (a) Anatomical diagram illustrates the uterine artery as the first branch of internal iliac artery, i.e., proximal to the inferior gluteal and superior gluteal arteries. (b) MIP image from MRA shows the left uterine artery. (c) DSA image obtained with selective internal left iliac artery catheterization clearly demonstrates a type IV uterine artery origin. Arrow points to the left uterine origin. UA- uterine artery. IG- inferior gluteal; SG- superior gluteal. Anatomical diagram adapted from Horton AW, Patel U, Belli AM. (2010) An unusual arterial supply to the uterus. A case report and review of anatomyimplications for uterine artery embolization. Clinical Radiology 65: References: Radiology, Hospital de São João - Porto/PT Uterine artery - anatomic variants: may be replaced by small arterial branches or may be absent;it is often replaced by the ipsilateral ovarian artery (Fig. 24 on page 61). the congenital absence of both uterine arteries is encountered in less than 1% of cases. Page 25 of 77

26 the presence of aberrant uterine vessels that originate in the abdominal aorta has been reported [18]. Fig. 24: MRA in a 37-year-old woman presenting for preembolization evaluation shows absence of the right uterine artery. (a) MIP image from MRA shows absence of the right uterine artery while the left uterine artery has normal features (arrowheads). No ovarian artery collateral supply to the uterus is depicted. Absence of the right uterine artery was confirmed by DSA (b) obtained with selective internal iliac artery catheterization. Additional arteries visualized include the common iliac (CI), external iliac (EI), internal iliac (II), superior gluteal (SG) and inferior gluteal (IG). References: Radiology, Hospital de São João - Porto/PT -Ovarian artery: arises anteromedially from the abdominal aorta a few centimeters below the renal arteries in 80%-90% of cases and has a characteristic corkscrew appearance. Page 26 of 77

27 Ovarian artery - anatomic variants: rarely, the ovarian artery arises from the renal, lumbar, adrenal, or iliac artery [18] (Fig. 25 on page 62). Fig. 25: MR angiography in a 34-year-old woman presenting for preembolization evaluation. MIP image from MRA (a) shows an enlarged left ovarian artery (arrow) arising from an accessory lower pole renal artery. Notice the characteristic corkscrew appearance of the ovarian artery (open arrow). A huge enhancing fibroid (F) is seen. No vascular supply to the fibroid from the left ovarian artery is depicted. DSA images (b,c) obtained with selective acessory left renal artery catheterization confirm aberrant origin of left ovarian artery. Arrow points to an enlarged left ovarian artery arising from acessory left renal artery. Once again notice the characteristic corkscrew appearance of the ovarian artery (open arrow). The lower renal pole (asterisk) is depicted. There is ovarian parenchymal blush (arrowhead) but no ovarian artery supply to the fibroid or the uterus is demonstrate. References: Radiology, Hospital de São João - Porto/PT Page 27 of 77

28 Practical relevance to UAE: although conventional angiography remains the gold standard for arterial visualization, MRA may help the interventionist to obtain a better understanding of the arterial anatomy before UAE [18]. ENLARGED OVARIAN ARTERY -Collateral ovarian artery supply of fibroids is a cause of incomplete infarction of fibroids and subsequent clinical failure of the procedure. -The identification of enlarged ovarian arteries at MRA can be helpful for prediction of ovarian artery embolization, although it has a relatively low sensitivity. However enlarged ovarian arteries identified on MRA can also be seen in type I ovarian artery to uterine artery anastomosis, which does not require ovarian artery embolization [1] (Fig. 26 on page 63). Practical relevance to UAE: knowledge regarding the presence of ovarian artery collateral supply to the fibroid before performing UAE is important for planning UAE as well as for selecting and counseling the patients, because ovarian artery embolization itself may result in ovarian dysfunction [1]. Page 28 of 77

29 Fig. 26: MR angiography in a 34-year-old woman presenting for preembolization evaluation. Bilateral selective ovarian arteriography was performed after UAE. MIP image from MRA (b) reveals an enlarged left ovarian artery (arrows) extending from the aorta to the pelvis however the right ovarian artery is not depicted. DSA image obtained with selective left ovarian artery catheterization (c) confirms the MRA finding of an enlarged left ovarian artery (arrows). Although not depicted in MRA, likely due to the small caliber, a right ovarian artery is nicely demonstrate in DSA image (a) obtained with selective right ovarian artery catheterization. At selective ovarian arteriography ovarian parenchymal blush is present bilateraly (arrowheads) but no fibroid stain was observed. Notice bilateral hydronephrosis, more marked in the right side (asterisks), likely related to compression caused by the bulky fibroid presented by the patient. References: Radiology, Hospital de São João - Porto/PT WHAT IS THE OPTIMAL PROJECTION ANGLE FOR ANGIOGRAPHIC SELECTION OF THE UTERINE ARTERY? Page 29 of 77

30 -The usual direction of tube obliquity (right oblique view for the left uterine artery and left oblique view for the right uterine artery) may fail to demonstrate the uterine artery origin, regardless of the obliquity angle used in this direction [2]. -No standard angle can be recommended for all patients [2]. Practical relevance to UAE: MRA is useful for predicting the optimal projection angle for angiographic selection of each uterine artery in each patient, which is instrumental in prompt catheterization of the uterine arteries, significantly reducing the radiation dose of UAE [2], an important issue in women of childbearing age (Fig. 27 on page 64). Fig. 27: MR angiography in a 40-year-old woman presenting for preembolization evaluation. (a) MIP image from MR angiography.the model was rotated to a 38 right obliquity (contrary to the usual left oblique view used for the right uterine artery) for demonstration of the origin (arrow) of the right uterine artery. (b) DSA image shows the corresponding angiographic projection and clear depicts of the origin (arrow) of the Page 30 of 77

31 right uterine artery. The projection angle for angiographic selection of uterine artery should be tailored individually as in this example. References: Radiology, Hospital de São João - Porto/PT 8.WHAT HAPPENS AFTER UAE? SUCCESSFUL EMBOLIZATION -Routine follow-up MRI after successful UAE will ideally show infarction of fibroids as complete lack of enhancement (Fig. 28 on page 65). -The reported reduction in fibroid size ranges from 42%-83%. Uterine size should also decrease, with reported reduction ranging from 43%-58% [20]. Page 31 of 77

32 Fig. 28: Successful fibroid embolization in a 34-year-old patient. (a) Sagittal T2weighted fast SE MR image before UAE shows a bulky fibroid (F). (b) Sagittal T1-weighted contrast-enhanced fat-saturated fast SE MR image demonstrates homogeneous avid enhancement of the fibroid. (c) Sagittal T1-weighted contrastenhanced fat-saturated fast SE MR image after UAE, shows nonenhancement of the fibroid and marked shrinkage.these findings are in keeping with successful fibroid embolization. References: Radiology, Hospital de São João - Porto/PT HEMORRHAGIC INFARCTION Key imaging findings: successful embolization is sometimes associated with T1shortening effects of methemoglobin and variable signal intensity on T2-weighted images depending upon the age of hemorrhage within the fibroid, known as hemorrhagic infarction [13] (Fig. 29 on page 66, Fig. 30 on page 67). Page 32 of 77

33 Fig. 29: Fibroid showing hemorrhagic infarction 7 months after UAE in a 37 yearold-woman. (a) Axial T1-weighted fast SE MR image shows increased signal intensity within the fibroid (F), secondary to internal hemorrhagic necrosis. (b) Axial T1-weighted contrast-enhanced fat-saturated fast SE MR image reveals nonenhancing fibroid, consistent with successful infarction. References: Radiology, Hospital de São João - Porto/PT Fig. 30: Fibroid showing hemorrhagic infarction 7 months after UAE in a 37 year-old-woman. (c) Sagittal T2-weighted and axial T1-weighted (d) fast SE MR images show increased signal intensity within the fibroid (F), secondary to internal hemorrhagic necrosis. Before UAE, the fibroid demonstrates typical low signal intensity on T2-weighted (e) and isosinal intensity compared to adjacent myometrium on T1-weighted (f) sequences. References: Radiology, Hospital de São João - Porto/PT FIBROID CALCIFICATION Page 33 of 77

34 -Typically occurs 6 months after UAE; can be peripheral or central. Key imaging findings: on MRI, the calcifications appear as areas of low signal on all sequences [13] (Fig. 31 on page 68). Fig. 31: Peripheral fibroid calcification 9 months after UAE in a 47-year-old woman. Axial oblique T1-weighted (a), sagittal T2-weighted (b) and sagittal T1weighted contrast-enhanced fat-saturated (c) fast SE MR images show peripheral hypointense rim (arrows) around the fibroid (F) consistent with calcification. References: Radiology, Hospital de São João - Porto/PT FIBROID LOCATION CHANGES -Changes in fibroid location after UAE (such as submucosal becoming endocavitary, or subserosal becoming intramural or even submucosal) may occur in 1-5% of cases [13] (Fig. 32 on page 69). Page 34 of 77

35 Fig. 32: Change in fibroid location in a 38-years-old-woman after UAE. (a) Sagittal T2-weighted fast SE MR image before UAE shows a submucosal (SM) and a subserous (SS) fibroids. Sagittal T2-weighted fast SE MR image after UAE (b), reveals that the subserous fibroid as become intramural (IM) in location. Additionally, the submucosal fibroid is becoming partially intracavitary with sloughed fibroid tissue (arrow) seen in the endometrial cavity. A vaginal tampon (T) is in situ. IC- intracavitary. References: Radiology, Hospital de São João - Porto/PT FIBROID RECURRENCE: REGROWTH INCOMPLETE FIBROID EMBOLIZATION AND -The goal of UAE is 100% infarction of uterine fibroids to achieve optimal and extended improvement in preprocedure symptoms [21].Residual viable leiomyoma tissue may result in failure of UAE due to regrowth of uterine fibroids [22] (Fig. 33 on page 70). Page 35 of 77

36 Fig. 33: Incomplete fibroid infarction after the first UAE in a 29 year-old-woman. (a) Sagittal T2-weighted fast SE MR image before UAE shows a bulky fibroid (F) measuring 10,7 x 7,0 cm. (b) Sagittal T1-weighted contrast-enhanced fat-saturated fast SE MR image obtained in a six-month follow-up after UAE, clearly demonstrates incomplete fibroid infarction, with enhancing viable tissue (asterisks) mostly at the periphery of the fibroid (F) along with some areas of non enhancement. Despite incomplete embolization, a significant decrease in uterine and fibroid size (measuring 5,4 x 5,5 cm) was achieved. References: Radiology, Hospital de São João - Porto/PT Page 36 of 77

37 Fig. 34: Fibroid regrowth after incomplete fibroid infarction, in the same patient. Successful reembolization was performed. Sagittal T2-weighted fast SE MR image (a) 5 years after the first UAE procedure shows a bulky fibroid (F) measuring 9,2 x 7,2 cm, consistent with fibroid regrowth. Sagittal T1-weighted contrast-enhanced fat-saturated fast SE MR image (b) three months after the second UAE procedure demonstrates complete lack of enhancement of the fibroid, consistent with successful reembolization. A small Naboth cyst is visible (arrow). References: Radiology, Hospital de São João - Porto/PT FIBROID RECURRENCE: NEWLY DEVELOPED FIBROIDS -Fibroid recurrence after UAE can occur due to newly developed fibroids tumor and/or to regrowth after incomplete embolization [23] (Fig. 7 on page 44). -Fibroid recurrence is a problem also seen with myomectomy and other uterine-sparing therapies [7]. Page 37 of 77

38 IMAGING OF COMPLICATIONS -Transcervical expulsion of a fibroid/fibroid tissue: one of the more common complications after UAE occurring in about 5% of patients and in some requiring surgical extraction [24] (Fig. 35 on page 72). -Submucosal fibroids, intramural fibroids in contact with the endometrial surface and intracavitary fibroids are at increased risk for transcervical expulsion. -MRI is the first-line modality in evaluating for suspected sloughing/expulsion of a fibroid [5]. Fig. 35: Sloughing of a treated fibroid 3 months after UAE in a 35 year-oldwoman. Sagittal T2-weighted fast SE MR image (a) before UAE shows a transmural fibroid located in the posterior corporal wall and uterine fundus, abutting the endometrium surface. Sagittal T1-weighted contrast-enhanced fatsaturated fast SE MR image (b) three months after UAE demonstrates complete Page 38 of 77

39 infartion of the fibroid whose posterior aspect is contiguous with the endometrial canal and that is beginning to pass (arrow) into the endometrial cavity (asterisk). References: Radiology, Hospital de São João - Porto/PT Images for this section: Fig. 1: Coexistence of a fibroid and adenomyosis in a 54-year-old woman presenting for preembolization evaluation. The patient was referred with an ultrasound examination reporting the presence of a large intramural fibroid in the anterior uterine wall. (a)sagittal T2-weighted fast SE image shows diffuse thickening of the junctional zone, more prominent anteriorly, consistent with diffuse adenomyosis (Ad). (b)the corresponding contrast-enhanced fat-saturated T1-weighted fast SE image shows diffuse heterogeneous enhancement throughout the myometrium without evidence of an underlying focal lesion besides a small intramural fibroid (F). The ultrasound features of adenomyosis can overlap with those of uterine fibroids resulting in misdiagnosis as in this case and additional imaging with MR is problem-solving. Page 39 of 77

40 Fig. 2: Ovarian fibroma simulating pedunculated subserosal fibroid in a 34-year-old woman. (a) Sagittal T2-weighted fast SE image shows a large solid lesion with a small peripheral cystic component (arrow), located adjacent to the uterine cervix. This lesion is hypointense compared to the myometrium. A small quantity of free fluid in pouch of Douglas is present (asterisk).(b,c) Contiguous sagittal contrast-enhanced T1-weighted fast SE images reveal the eccentrically located ipsilateral ovary (circle) in the periphery of the fibroma and a small peripheral cystic component (arrow). The fibroma enhances less than the myometrium. An innacurate preoperative diagnosis of a pedunculated subserosal fibroid with cystic degeneration was made; the diagnosis of an ovarian fibroma was pathologically proved. OvF-ovarian fibroma. Page 40 of 77

41 Fig. 3: Pedunculated subserosal fibroid simulating an adnexal mass in a 40-year-old woman presenting for preembolization evaluation. (a) Sagittal T2-weighted fast SE image shows a large hypointense lesion adjacent to the uterus. Sagittal contrast-enhanced T1weighted fast SE MR images (b,c) reveal a stalk (arrow) connecting the lesion to the uterine fundus and multiple vessels (circle) between the uterus and the lesion, appearing as curvilinear tortuous flow voids (the bridging vessel sign), confirming the diagnosis of a fibroid, thereby allowing exclusion of an adnexal mass. Page 41 of 77

42 Fig. 4: Coexistence of fibroids and dermoid cyst in a 33-year-old woman presenting for preembolization evaluation. (a) Sagittal T2-weighted fast SE image reveals a large fibroid (F). A complex, moderately hyperintense, right ovarian lesion (D) containing internal debris and/or nodularity is depicted within the pouch of Douglas. Page 42 of 77

43 Fig. 5: Coexistence of fibroids and dermoid cyst in a 33-year-old woman presenting for preembolization evaluation. Axial T2-weighted (b) and axial T2-weighted fat-saturated (c) fast SE images shows a drop in the signal intensity of the non-dependent part of the right ovarian lesion (arrow), indicating macroscopic fat content and suggesting the diagnosis of a dermoid cyst. A fat-fluid level is present.internal debris and/or nodularity is noted (circle). F-fibroid. Page 43 of 77

44 Fig. 6: Coexistence of fibroids and dermoid cyst in a 33-year-old woman presenting for preembolization evaluation. Saggital contrast-enhanced fat-saturated T1-weighted fast SE images, before (d) and after (e) UAE, demonstrated the presence of macroscopic fat (asterisk) and an absence of enhancement, allowing the diagnosis of a dermoid cyst (D). Note the complete lack of enhancement of the fibroid (F) after UAE, in keeping with successful embolization. The diagnosis of dermoid cyst (mature cystic teratoma) was pathologically proved. Page 44 of 77

45 Fig. 7: Suspicion of uterine leiomyosarcoma in a 31 year-old-woman with a history of two previous UAE, the most recent 5 years prior to current MR examination, presenting with epigastric pain, anorexia and enlarging myometrial mass despite previous embolizations. Sagittal (a) and coronal (b) T2-weighted fast SE images show a huge uterus containing a heterogeneous mass (arrows) arising from the fundus, with necrotic/cystic areas (C). The remarkable increase in size and the presence of necrotic/cystic areas, did not allowed ruling out the possibility of a leiomyossarcoma. At pathology, it was in fact a leiomyoma. Several newely developed fibroids (F) were identified, in keeping with recurrence. Page 45 of 77

46 Fig. 8: Suspicion of uterine leiomyosarcoma in a 31 year-old-woman with a history of two previous UAE. Sagittal (a) and axial oblique (b) T1-weighted contrast-enhanced fatsaturated fast SE images after the second UAE shows a normal sized uterus with two small viable fibroids (arrows). Page 46 of 77

47 Fig. 9: UAE in a 40-year-old patient having a copper-containing intrauterine device (IUD). (a) Axial T2-weighted fast SE image clearly depicts a T-shaped IUD as a no-signal zone inside the uterine cavity, without susceptibility artifacts. (b) Uterine angiogram obtained before embolization shows a large fibroid (F) projecting from the left side of the uterus. The IUD is seen. Page 47 of 77

48 Fig. 10: Technically successful UAE in a 33-year-old patient presenting with a huge fibroid measuring 16,5 cm in long axis. (a)sagittal T2-W fast SE image before UAE shows a huge fibroid (F). (b)sagittal T1-W contrast-enhanced fat-saturated fast SE image, obtained three months after UAE, shows a still bulky fibroid (F), with complete lack of enhancement, consistent with successful embolization. An additional shrinkage of fibroid within the next months is expected to occur. Page 48 of 77

49 Fig. 11: Hypervascular fibroids in 33-year-old woman presenting for preembolization evaluation. Sagittal (a) and axial (d) T2-weighted fast SE images show two intramural fibroids slightly hyperintense (reflecting high cellularity and relatively less stroma). On T1-weighted fast SE image (c) the fibroids are isointense with the myometrium. After gadolinium administration (b) both fibroids show remarkable contrast enhancement, enhancing more than the myometrium, according to their hypervascular nature. These findings are consistent with celullar fibroids. Page 49 of 77

50 Fig. 12: Self-infarcted fibroid in a 33-year-old woman presenting for preembolization evaluation. (a) Sagittal T2-weighted fast SE image shows several fibroids (F1,F2,F3). After gadolinium administration (b) F1 shows complete lack of enhancement, consistent with non viable fibroid. F2 is hypovascular, showing a relative lack of enhancement. F3 presents the most common enhacement pattern - slight hypovascular compared with the adjacent myometrium. The endometrial canal (arrow) can be seen sandwiched between the fibroids. Page 50 of 77

51 Fig. 13: Sloughing of a submucosal fibroid in a 38-years-old-woman after UAE. (a) Sagittal T2-weighted fast SE image before UAE shows a submucosal fibroid (SMF). (b) Sagittal T2-weighted fast SE MR image after UAE clearly shows that the submucosal fibroid is becoming partially intracavitary with sloughed fibroid tissue (arrow) seen in the endometrial cavity. Notice an area of high T2 signal intensity (open arrow) consistent with partial liquefaction of the infarcted fibroid. A vaginal tampon (T) is in situ. Page 51 of 77

52 Fig. 14: Successful embolization of cervical fibroid in a 32-year-old woman with multiple fibroids. (a) Sagittal T2-weighted fast SE image shows several fibroids with the typical homogeneous hypointensity, one of which is cervical in location (CF). (b) After UAE, sagittal T1-weighted contrast-enhanced fat-saturated fast SE image shows complete lack of enhancement of all fibroids, consistent with successful embolization. The cervical fibroid exhibits significant decrease in size, from 7,2 cm to 4,3 cm in long axis. Although cervical fibroids are more resistant to complete infarction after UAE than are other fibroids subtypes, this case demonstrates a good outcome. Page 52 of 77

53 Fig. 15 Page 53 of 77

54 Fig. 16 Page 54 of 77

55 Fig. 17: MR angiography in a 34-year-old-woman presenting for preembolization evaluation shows a hypertrophic right uterine artery and a small caliber left uterine artery. (a) MIP image from MRA depicts a prominent right uterine artery (arrow). (b) DSA image obtained with selective right internal iliac artery catheterization confirms the MRA findings. (c) Right para-sagittal T2-weighted fast SE image depicts a bulky fibroid (F). Notice the flow voids (circle) appearing as hypointense structures at the interface between the fibroid and the myometrium, in relation with dilated feeding arteries with fast flow, feeding the vascular plexus of the fibroid. Right ovary has unremarkable appearance (asterisk). Page 55 of 77

56 Fig. 18: MR angiography in 34-year-old-woman presenting for preembolization evaluation shows a hypertrophic right uterine artery and a small caliber left uterine artery. (d) MIP image from MRA in a 38 left obliquity nicely depicts a small caliper left uterine artery (arrow). Notice that the oblique view helps identify the optimal angle for left uterine artery origin. (e) DSA image shows the corresponding angiographic projection and clear demonstration of the origin (arrow) of the left uterine artery arising from the proximal inferior gluteal artery, in accordance with the MR angiographic findings. Page 56 of 77

57 Fig. 19: MR angiography in a 35-year-old-woman presenting for preembolization evaluation. MIP image from MRA depicts two uterine arteries of similar normal caliber (arrows). Page 57 of 77

58 Fig. 20: MR angiography in a 31-year-old woman presenting for preembolization evaluation with angiographic correlation. (a)anatomical diagram illustrates the uterine artery as the first branch of the inferior gluteal artery. (b)mip image from MRA depicts a type I uterine artery origin. (c)dsa obtained with selective left internal iliac artery catheterization demonstrates good correlation with MR angiography. UA- uterine artery; CI- common iliac; II- internal iliac; EI- external iliac; IL- iliolumbar; SG- superior gluteal; IGinferior gluteal. Anatomical diagram adapted from Horton AW, Patel U, Belli AM. (2010) An unusual arterial supply to the uterus. A case report and review of anatomy-implications for uterine artery embolization. Clinical Radiology 65: Page 58 of 77

59 Fig. 21: (a)anatomical diagram illustrates the uterine artery as the second or third branch of the inferior gluteal artery. (b)dsa image shows the uterine artery (small arrow) as the second branch of the inferior gluteal artery. The internal pudendal artery (arrow), is the first branch of the inferior gluteal artery. UA-uterine artery; IP-internal pudendal. Anatomical diagram adapted from Horton AW, Patel U, Belli AM. (2010) An unusual arterial supply to the uterus. A case report and review of anatomy-implications for uterine artery embolization. Clinical Radiology 65: DSA image adapted Gomez-Jorge J, Keyoung A, Levy EB, Spies JB.Uterine artery anatomy relevant to uterine leiomyomata embolization (2003) Cardiovasc Intervent Radiol 26: Page 59 of 77

60 Fig. 22: MR angiography in a 41-year-old woman presenting for preembolization evaluation with angiographic correlation. (a)anatomical diagram illustrates the uterine artery, the inferior gluteal and the superior gluteal arteries branching at the same level from the internal iliac artery, as a trifurcation. (b) MIP image from MRA nicely depicts trifurcation of the right internal iliac artery. (c) DSA obtained with selective internal iliac artery catheterization demonstrates good correlation with MRA. UA- uterine artery; IIinternal iliac; SG- superior gluteal; IG- inferior gluteal. Anatomical diagram adapted from Horton AW, Patel U, Belli AM. (2010) An unusual arterial supply to the uterus. A case report and review of anatomy-implications for uterine artery embolization. Clinical Radiology 65: Page 60 of 77

61 Fig. 23: MR angiography in a 35-year-old woman presenting for preembolization evaluation with angiographic correlation. (a) Anatomical diagram illustrates the uterine artery as the first branch of internal iliac artery, i.e., proximal to the inferior gluteal and superior gluteal arteries. (b) MIP image from MRA shows the left uterine artery. (c) DSA image obtained with selective internal left iliac artery catheterization clearly demonstrates a type IV uterine artery origin. Arrow points to the left uterine origin. UA- uterine artery. IGinferior gluteal; SG- superior gluteal. Anatomical diagram adapted from Horton AW, Patel U, Belli AM. (2010) An unusual arterial supply to the uterus. A case report and review of anatomy-implications for uterine artery embolization. Clinical Radiology 65: Page 61 of 77

62 Fig. 24: MRA in a 37-year-old woman presenting for preembolization evaluation shows absence of the right uterine artery. (a) MIP image from MRA shows absence of the right uterine artery while the left uterine artery has normal features (arrowheads). No ovarian artery collateral supply to the uterus is depicted. Absence of the right uterine artery was confirmed by DSA (b) obtained with selective internal iliac artery catheterization. Additional arteries visualized include the common iliac (CI), external iliac (EI), internal iliac (II), superior gluteal (SG) and inferior gluteal (IG). Page 62 of 77

63 Fig. 25: MR angiography in a 34-year-old woman presenting for preembolization evaluation. MIP image from MRA (a) shows an enlarged left ovarian artery (arrow) arising from an accessory lower pole renal artery. Notice the characteristic corkscrew appearance of the ovarian artery (open arrow). A huge enhancing fibroid (F) is seen. No vascular supply to the fibroid from the left ovarian artery is depicted. DSA images (b,c) obtained with selective acessory left renal artery catheterization confirm aberrant origin of left ovarian artery. Arrow points to an enlarged left ovarian artery arising from acessory left renal artery. Once again notice the characteristic corkscrew appearance of the ovarian artery (open arrow). The lower renal pole (asterisk) is depicted. There is ovarian parenchymal blush (arrowhead) but no ovarian artery supply to the fibroid or the uterus is demonstrate. Page 63 of 77