Magnetic Resonance Signal Intensity Ratio Measurement Before Uterine Artery Embolization: Ability to Predict Fibroid Size Reduction

Evidences in Uterine Artery Embolization: A Radiologist's Primer

Uterine artery embolization is an established minimally invasive therapy for symptomatic fibroids. It has also been used for other diseases of the uterus, including adenomyosis, uterine arteriovenous malformation, ectopic pregnancy, abnormal invasive placenta, and postpartum hemorrhage. In this review, we provide an updated and comprehensive review of uterine artery embolization based on the evidence published. We review the indications, the role of MRI, technical aspects, and complications of the procedure. The issues with a future pregnancy, risk of infertility, and fetal radiation are discussed as well.

Uterine Artery Embolization of Uterine Leiomyomas: Predictive MRI Features of Volumetric Response

OBJECTIVE. The purpose of this article was to evaluate MRI features of uterine leiomyomas that predict volumetric response after uterine artery embolization (UAE). MATERIALS AND METHODS. This retrospective study included 75 patients with 212 uterine leiomyomas who were successfully treated between August 2013 and December 2018. To predict uterine volumetric response, age, number of lesions, and baseline uterine volume were assessed. To predict leiomyoma volumetric response, a multivariate regression analysis was performed to evaluate six predictive factors: location, baseline leiomyoma volume, signal intensity on T1-weighted and T2-weighted MRI, heterogeneity of signal intensity on T2-weighted MRI, and vascularity on subtraction imaging (SI). A five-variable predictive ROC model was developed to evaluate the diagnostic accuracy of the signal intensity ratio on T2-weighted MRI, enhancement ratio, heterogeneity ratio on T2-weighted MRI, location, and baseline leiomyoma volume in predicting at least 40% leiomyoma volumetric response. RESULTS. Age, number of leiomyomas, and baseline uterine volume were not predictive of uterine volumetric response. A submucosal location was the best predictive factor of leiomyoma volumetric response, and it showed 32.2% more leiomyoma volumetric response compared with a nonsubmucosal location (p < .001). Hyperintensity on T2-weighted MRI was the second best predictive factor of leiomyoma volumetric response, and it showed 16.9% more volumetric response compared with hypointense leiomyomas (p = .013). A small baseline leiomyoma volume (< 58 cm³) was associated with 10.2% more leiomyoma volumetric response compared with larger leiomyomas (p = .01). Leiomyomas that were hyperintense on SI showed 7.9% more leiomyoma volumetric response compared with those that were hypointense (p = .014). The five-variable ROC model showed high diagnostic accuracy with an AUC of 0.85, sensitivity of 82%, and specificity of 71%. CONCLUSION. A submucosal location, hyperintensity on T2-weighted MRI, small baseline leiomyoma volume (< 58 cm³), and hyperintense leiomyoma on subtraction imaging are the main independent favorable predictors of leiomyoma volumetric response after UAE. An accurate predictive ROC model was developed that may help in selecting patients suitable for UAE. Quantitative assessment of heterogeneity on T2-weighted MRI showed promising results as a predictor of volumetric response, and further research in this area using texture analysis and radiomics is suggested.

Magnetic resonance imaging findings of invasive breast cancer in different histological grades and different histopathological types

BACKGROUND

The aim of this study was to evaluate the magnetic resonance imaging (MRI) findings of invasive breast cancer in different histopathological types (invasive ductal carcinoma (IDC), invasive lobular carcinoma (ILC) and mixed ductal-lobular carcinoma (MDLC)) and different histological grades.

METHODS

A retrospective review was made of 1256 patients who underwent breast MRI at our hospital between January 2015 and December 2018. A total of 152 lesions (27 ILC, 102 IDC, 23 MDLC and 20 grade 1, 83 grade 2 and 49 grade 3) were included in the study. All the lesions were evaluated according to size, shape, margin, dynamic curve, ADC value and T2 signal intensity ratio (SIR).

RESULTS

Most of the lesions tended to show type 2 and type 3 dynamic curve, type 1 dynamic curve was more commonly seen in ILC and grade 1 groups. IDC showed higher T2 SIR than the other types and grade 3 showed higher T2 SIR than other grades (p< 0,05) There was no statistically significant difference between the groups according to morphological features and mean ADC values (p > 0,05).

CONCLUSION

T2 SIR and dynamic curve can help the radiologists predict histopathological findings while morphological features and ADC values were not helpful in distinguishing histological types and grades.

Impact of evaluation in interventional radiology clinic prior to uterine artery embolization: changes in management

PURPOSE

To assess the impact of pre-procedural evaluation of patients with symptomatic uterine fibroids and adenomyosis in interventional radiology (IR) clinic.

METHOD

In this IRB-approved, HIPAA-compliant retrospective study, consecutive patients evaluated in the IR clinic in a tertiary academic hospital between 1/1/2015 and 9/30/2018 by a single board-certified interventional radiologist were included. Medical records were reviewed to obtain medical history, imaging and endometrial biopsies results. Impact of IR clinic assessment of clinical, imaging, and pathological findings on patient's clinical course was assessed. Descriptive statistics were used.

RESULTS

208 consecutive patients were evaluated in clinic for uterine fibroids 176/208 (85%), adenomyosis 8/208 (4%) or both 24/208 (11%) with age of 44.4 ± 5.8 years and BMI of 30.1 ± 8.6 kg/m². Leading presenting symptom was menorrhagia in 172/208 (80%) patients, pelvic pain in 91/208 (44%), and urinary symptoms in 88/208 (42%) patients. 159/208 (76%) patients underwent UAE, 12/208 (6%) patients underwent surgery, and 37/208 (18%) patients chose conservative management. 189/208 (91%) patients had pelvic MRI that altered management course in 7/189 (4%) patients due to intracavitary fibroids in two patients, endometrial polyps in two patients, non-enhancing fibroids in two patients, and adnexal mass in one patient. 166/208 (80%) underwent endometrial biopsy that altered management course in one patient (0.6%) due to endometrial intraepithelial neoplasia.

CONCLUSION

Endometrial biopsy and pelvic MRI are helpful to detect cases of non-enhancing fibroids, intracavitary fibroids, and ovarian and endometrial malignancies and thus altered management of five percent of patients with symptomatic fibroids and adenomyosis.

The utility of apparent diffusion coefficients for predicting treatment response to uterine arterial embolization for uterine leiomyomas: a systematic review and meta-analysis

PURPOSE

Apparent diffusion coefficient (ADC) values, which are derived from diffusion-weighted imaging, have a potential role for predicting treatment response. A systematic review was conducted to examine the value of baseline ADC values for predicting leiomyoma size reduction after uterine arterial embolization (UAE).

METHODS

Study selection, quality appraisal and data extraction were conducted independently by two authors. Statistical analyses included the calculation of weighted means and summary correlation coefficients (under the random effects model).

RESULTS

Eleven studies consisting of a total of 258 patients (age, weighted mean±standard deviation [SD], 43.1±10.1 years) were included. The weighted mean±SD ADC value was 1.2±1.5 ×10-3 s/mm2 at baseline (ten studies) and 1.3±2.8 ×10-3 s/mm2 at approximately 6 months after embolization (six studies). The weighted mean percentage leiomyoma volume reduction (VR) at 6 months was 47.1%±35.6% (seven studies). Based on four studies, the weighted summary correlation coefficient for the correlation between baseline ADC and leiomyoma VR at approximately 6 months was not significant (r=0.40; 95% CI, -0.07 to 0.72; I2=69.7%). No associations were found in three of the four studies that examined changes in ADC values as a predictor.

CONCLUSION

Due to high heterogeneity, it is unclear whether ADC may be useful for predicting treatment responses to UAE.

Feasibility of quantitative MR-perfusion imaging to monitor treatment response after uterine artery embolization (UAE) in symptomatic uterus fibroids

INTRODUCTION

In 25% of women, symptomatic uterus myomas are diagnosed with clinical and functional impairment ranging from abdominal and pelvic pain to dys- and hypermenorrhea, dyspareunia, pollakiuria and infertility. Women undergoing a treatment increasingly prefer nowadays minimal invasive, uterus preserving therapies like uterine artery embolization (UAE) over surgical hysterectomy, nowadays. To emphasize the efficacy of UAE as a uterus preserving treatment with targeted therapy of myomas only, analysis of tissue perfusion pre and post embolization is required. The purpose of this study was to assess treatment response in UAE in females with symptomatic uterus myomas by quantitative magnetic resonance perfusion imaging.

METHODS

Seven females scheduled for uterus myoma embolization underwent three MRI examinations (pre, post, follow-up) including morphological and dynamic contrast enhanced perfusion imaging at 3 T. To measure tumor volume, regions-of-interest covering the tumor and the uterus were drawn by two readers in consensus. Blood flow, blood volume, and mean transit time were calculated by a pixel-by-pixel deconvolution approach. Kruskal-Wallis/Friedman test was employed to test whether the group medians differ significantly with correction for multiple comparisons using Bonferroni method.

RESULTS

Change of volume could be observed in all patients after embolization but was significantly different only between pre/post and follow-up time point. Measured differences in all perfusion parameters were significant between pre-intervention and post-intervention/follow-up in the myomas, no significant differences could be detected for the uterus tissue.

CONCLUSIONS

Our results demonstrate devascularization of symptomatic myomas which correlates with cessation of hypermenorrhea in all treated patients without affecting healthy uterus tissue. Supplementing UAE with perfusion imaging to monitor early treatment response is feasible and might provide valuable information for the follow-up of patients and contribute to providing confidence for the patients in treatment success.

Susceptibility weighted MRI after uterine artery embolization for leiomyoma

PURPOSE

To evaluate whether susceptibility-weighted MR imaging (SWI) findings are associated with tumor infarction on contrast-enhanced MRI (CE-MRI) after uterine artery embolization (UAE) for leiomyoma.

METHODS

This was a single institution, retrospective study. Between February 2016 and April 2017, 27 consecutive patients underwent UAE and completed SWI and CE-MRI before and 1 week after UAE. Two blinded readers independently reviewed the MRI of 261 tumors ≥1 cm in all patients. We evaluated the relationship between the hypointense peripheral rim observed on the tumor surface on post-procedural SWI and the infarction rates (≥90%, <90%) of each tumor based on post-procedural CE-MRI. Inter-reader correlation coefficients (ICC) and the sensitivity and specificity of the rim were measured.

RESULTS

Substantial inter-reader agreement was noted in post-procedural SWI interpretations (ICC = 0.681, 95% CI; 0.547, 0.771). The rim was observed in 66.7% (174/261) of tumors by reader 1 and 55.9% (146/261) of tumors by reader 2 on post-procedural SWI. Correlations were observed between the rim and ≥90% tumor infarction by readers 1 and 2 (Spearman's coefficient = 0.474 and 0.438, p < 0.001 and p < 0.001, respectively). The sensitivity and specificity of the rim to tumor infarction were 77.2 and 82.6% (reader 1), and 65.8 and 100% (reader 2), respectively.

CONCLUSIONS

The present study demonstrated that the hypointense peripheral rim was observed on some leiomyomas on SWI immediately after UAE. The rim correlated with tumor infarction on post-procedural CE-MRI. This SWI finding was helpful for evaluating embolic effects on leiomyomas in the acute phase after UAE.

Use of pre-operative imaging for symptomatic uterine myomas during pregnancy: a case report and a systematic literature review

PURPOSE

Uterine fibroids (UFs) occur in 10% of pregnancies and may lead to severe maternal-fetal complications, mainly depending on UFs characteristics and the distance to the uterine cavity (UC). When symptomatic, UFs are managed medically. Nevertheless, in about 2% of cases, surgery becomes necessary. Entry into the UC should be avoided during myomectomy. Consequentially, pre-operative assessment of this risk could be beneficial. Ultrasonography (US) represents the gold standard for UFs assessment; however, scarce evidence has been produced to assess the role of magnetic resonance imaging (MRI). The aim of the present study was to summarize current evidence about the pre-operative use of imaging techniques for UFs during pregnancy.

METHODS

A systematic research of the literature was conducted in Scopus, PubMed/MEDLINE, ScienceDirect and the Cochrane Library, including case reports and case series. A case report was also discussed. We collected data regarding patients, imaging assessment, UFs characteristics, surgical information, timing and modality of delivery.

RESULTS

According to our search strategy, 66 articles were selected and 210 patients were included. US assessment was reported in 36 (17%) cases. MRI was reported in 10 (4.7%) cases. Only in one case, MRI was used to measure the distance between UFs and UC.

CONCLUSION

US allows an adequate pre-operative evaluation of anterior, submucosal or pedunculated symptomatic UFs in pregnancy. However, compared to US, MRI may provide a more accurate evaluation of multiple, large, intramural or posterior UFs and could measure the distance between UFs and UC more accurately.