Preinterventional quantitative magnetic resonance imaging predicts uterus and leiomyoma size reduction after uterine artery embolization

Inter- and intra-rater reproducibility of quantitative T1 measurement using semiautomatic region of interest placement in myometrium

PURPOSE

This study aimed to investigate the inter- and intraobserver reproducibility of quantitative T1 (qT1) measurements using manual and semiautomatic region of interest (ROI) placements. We hypothesized the usefulness of the semiautomatic method, which utilizes a three-dimensional (3D) anatomical relationship between the myometrium and other tissues, for minimizing ROI placement variation, thereby improving qT1 reproducibility compared to the manual approach. The semiautomatic approach, which considered anatomical relationships, was expected to enhance reproducibility by reducing ROI placement variabilities.

MATERIALS AND METHODS

This study recruited 23 healthy female volunteers. Data with variable flip angle (VFA) and inversion recovery were acquired using 3D-spoiled gradient echo and spin echo sequences, respectively. T1 maps were generated with VFA. Manual and semiautomatic ROI placements were independently conducted. Mean qT1 values were calculated from the T1 maps using the corresponding pixel values of the myometrial ROI. Inter- and intraobserver reproducibility of qT1 values was investigated. The inter- and intraobserver reproducibility of qT1 values was evaluated by calculating the coefficient of variation (CoV). Further, reproducibility was evaluated with inter- and intraobserver errors and intraclass correlation coefficients (ICCs). Bland-Altman analysis was utilized to compare the results, estimate bias, and determine the limits of agreement.

RESULTS

The mean inter- and intraobserver CoV of the qT1 values for semiautomatic ROI placement was significantly lower than those for manual ROI placement (p < 0.05 and p < 0.01, respectively). ICCs for semiautomatic ROI placement were greater than those for manual ROI placement. Further, the mean inter- and intraobserver errors for semiautomatic ROI placement were significantly lower than those for manual ROI placement (p < 0.05 and p < 0.01, respectively).

CONCLUSION

Semiautomatic ROI placement demonstrated high reproducibility of qT1 measurements compared with manual methods. Semiautomatic ROI placement may be useful for evaluating uterine qT1 with high reproducibility.

Uterine Artery Embolization for the Treatment of Symptomatic Uterine Fibroids of Different Sizes: A Single Center Experience

The present study aimed to evaluate the clinical and radiological 1-year outcomes of uterine artery embolization (UAE) performed in a selected population of women with symptomatic myomas and who do not wish to conceive. Between January 2004 and January 2018, a total of 62 patients with pre-menopausal status and with no wish to conceive in the future underwent UAE for the treatment of symptomatic fibroids. All the patients underwent magnetic resonance imaging (MRI) and/or transvaginal ultrasonography (TV-US) before and after the procedure at 1-year follow-up. Clinical and radiological parameters were recorded, stratifying the population into 3 groups according to the size of the dominant myoma (group 1: <50 mm; group 2: ≥50 and ≤80 mm; group 3: >80 mm). Mean fibroid diameter was significantly reduced (42.6% ± 21.6%) at 1-year follow-up, with excellent improvements in terms of both symptoms and quality of life. No significant difference was observed regarding baseline dimension and the number of myomas. No major complications were reported (2.5%). The present study confirms the safety and efficacy of UAE in the treatment of symptomatic fibroids in pre-menopausal women with no desire to conceive.

ACR Appropriateness Criteria® Fibroids

Uterine fibroids (leiomyomas or myomas) are the most common neoplasm of the uterus. Though incompletely understood, fibroid etiology is multifactorial, a combination of genetic alterations and endocrine, autocrine, environmental, and other factors such as race, age, parity, and body mass index. Black women have greater than an 80% incidence of fibroids by age 50, whereas White women have an incidence approaching 70%. Fibroid symptoms are protean, and menorrhagia is most frequent. The societal economic burden of symptomatic fibroids is large, 5.9 to 34.3 billion dollars annually. There are a variety of treatment options for women with symptomatic fibroids ranging from medical therapy to hysterectomy. Myomectomy and uterine fibroid embolization are the most common uterine sparing therapies. Pelvic ultrasound (transabdominal and transvaginal) with Doppler and MRI with and without intravenous contrast are the best imaging modalities for the initial diagnosis of fibroids, the initial treatment of known fibroids, and for surveillance or posttreatment imaging. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer-reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer-reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Can pre-procedural MRI signal intensity ratio predict the success of uterine artery embolization in treatment of myomas?

Background/aim

Magnetic resonance (MR) images, signal intensity ratios calculated using region of interests (ROI) in T2W images by proportioning the dominant myoma to iliac muscle can aid patient selection and, thus, in achieving better outcomes with the uterine artery embolization (UAE) procedure. The present study investigates the association between the success of UAE treatment with signal intensity (SI) ratio of the dominant myoma to the iliac muscle in MR imaging performed prior to the procedure.

Materials and methods

This is a retrospective study and included 30 patients who admitted to our clinic between February 2017 and July 2019 due to symptoms associated with myoma and who underwent MR imaging before and after UAE treatment. All patients, MR images obtained before UAE treatment and at the 12th month after the procedure were evaluated. In MRI, SI values were calculated by proportioning the dominant myoma to the iliac muscle using circular ROI in T1 weighted (W), T2W, and post-contrast T1W images. In the present study, 50% or more volumetric regression of the myoma with infarction of fibroids (loss of enhancement) at the 12-month follow-up MRI after the procedure was considered a successful procedure.

Results

Myoma volumes calculated in MR images showed significant differences between the MRI performed before UAE procedure and the MRI performed at the 12th month after the procedure (p < 0.0001). SI ratio calculated from pre-procedure T2W MR images was found to be a significant determinant of 50% or more volumetric regression in the myoma after UAE procedure (p = 0.017), T1W, post-contrast T1W images were not statistically significant (p = 0.211).

Conclusion

Our results indicate that SI ratio of the dominant myoma to the iliac muscle calculated using ROI in T2W images of MR studies performed before UAE procedure can predict the success of the procedure.

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.

Endovascular treatment of uterine myomatosis: a systematic review

Uterine Artery Embolization (UAE) is a noninvasive alternative to open surgery for treatment of uterine myomatosis. This study aims to analyze the efficacy and safety of UAE in these cases. A systematic review was carried out of studies available on the Medline (via PubMed) and the LILACS and PEDro (via the Biblioteca Virtual em Saúde) databases. The searches found 817 studies, 7 of which were selected according to the eligibility criteria (analytical, longitudinal, retrospective, or prospective studies), with a total of 367 patients studied. The variables analyzed and the characteristics of the studies included were collated and input to a database. Rates of volume reduction of the uterus and the dominant myoma were 44.1% and 56.3%, respectively. Mean rate of complete infarction of the dominant myoma was 88.6% (82-100%). The mean number of complications observed was 15±8.6 cases, most of which were classified as minor, and no deaths were recorded. The mean number of re-interventions in absolute values was 12.2±15.5 cases. Therefore, in the literature analyzed, uterine artery embolization is an effective procedure with a low rate of complications for treatment of uterine leiomyomatosis.

Use of multiparametric MRI to characterize uterine fibroid tissue types

BACKGROUND

Although the biological characteristics of uterine fibroids (UF) have implications for therapy choice and effectiveness, there is limited MRI data about these characteristics. Currently, the Funaki classification and Scaled Signal Intensity (SSI) are used to predict treatment outcome but both screening-tools appear to be suboptimal. Therefore, multiparametric and quantitative MRI was studied to evaluate various biological characteristics of UF.

METHODS

87 patients with UF underwent an MRI-examination. Differences between UF tissues and myometrium were investigated using T2-mapping, Apparent Diffusion Coefficient (ADC) maps with different b-value combinations, contrast-enhanced T1-weighted and T2-weighted imaging. Additionally, the Funaki classification and SSI were calculated.

RESULTS

Significant differences between myometrium and UF tissue in T2-mapping (p = 0.001), long-TE ADC low b-values (p = 0.002), ADC all b-values (p < 0.001) and high b-values (p < 0.001) were found. Significant differences between Funaki type 3 versus type 1 and 2 were observed in SSI (p < 0.001) and T2-values (p < 0.001). Significant correlations were found between SSI and T2-mapping (p < 0.001; ρ_s = 0.82), ADC all b-values (p = 0.004; ρ_s = 0.31), ADC high b-values (p < 0.001; ρ_s = 0.44) and long-TE ADC low b-values (p = 0.004; ρ_s = 0.31).

CONCLUSIONS

Quantitative MR-data allowed us to distinguish UF tissue from myometrium and to discriminate different UF tissue types and may, therefore, be a useful tool to predict treatment outcome/determine optimal treatment modality.

Development of a Model for the Prediction of Treatment Response of Uterine Leiomyomas after Uterine Artery Embolization

Background: Uterine artery embolization (UAE) is one of the minimally-invasive alternatives to hysterectomy for treatment of uterine leiomyomas. There are various factors affecting the outcomes of UAE, but these have only been sporadically studied. Study Objective: To identify factors associated with the efficacy of UAE for the treatment of uterine leiomyoma, and to develop a model for the prediction of treatment response of uterine leiomyomas to UAE. Study design: A retrospective cohort study (Canadian Task Force Classification II-2) Patients: One hundred ninety-eight patients with symptomatic uterine leiomyomas. Intervention: UAE Measurements and Main Results: Among 198 leiomyoma patients who were treated with UAE, 104 who underwent pelvic magnetic resonance imaging (MRI) with diffusion-weighted imaging were selected for developing prediction model. Variables that were statistically significant from the univariate analysis were: location of leiomyoma, total number of lesions, sum of leiomyomas diameters, T2 signal intensity of largest leiomyoma, and T2 leiomyoma:muscle ratio. After a logistic regression analysis, leiomyoma location and T2 signal intensity of the largest leiomyoma were found to be statistically significant variables. Using intramural myomas defined as controls, submucosal leiomyomas showed a greater response to UAE with an odds ratio of 7.6904. The odds ratio of T2 signal intensity with an increase in signal intensity of 10 was 1.093. Using these two variables, we developed a prediction model. The AUC in the prediction model was 0.833, and the AUC in the validation set was 0.791. Conclusion: We identified that submucosal leiomyomas and those leiomyomas that show high signal intensity on T2-weighted imaging will exhibit a greater response to UAE. Prediction models are clinically helpful in selecting UAE as an appropriate treatment option for managing uterine leiomyoma.

Predicting the results of uterine artery embolization: correlation between initial intramural fibroid volume and percentage volume decrease

Introduction and objective

Uterine artery embolization (UAE) is a minimally invasive treatment option for symptomatic fibroids. Long-term follow-up studies have shown that at five-year follow-up after UAE, up to 30% of patients required a hysterectomy. Therefore, it seems of utmost importance to identify patients, who are unlikely to benefit from UAE. It has been postulated that the percentage volume reduction of fibroids may predict long-term UAE outcome. The results of available studies are equivocal, therefore it seemed of interest to investigate the correlation between the preinterventional intramural fibroid volume and imaging outcome of UAE in premenopausal patients.

Material and methods

Uterine artery embolization was performed in 65 premenopausal patients with symptomatic, intramural fibroids. Dominant fibroid volume was assessed using an integrated VOCAL (Virtual Organ Computer-aided AnaLysis) imaging program at baseline and 3 months after UAE. The percentage reduction of fibroid volume was calculated. The association between preinterventional fibroid volumes and percentage volume reductions was determined with the Spearman rank correlation test.

Results

Before UAE, the median dominant fibroid volume was 101 cm³ (range 23.6-610). At three-month follow-up the median dominant leiomyoma volume decreased to 50.4 cm³ (range 6.9-193.9). Median percentage reduction of fibroid volume three months after UAE was calculated at 50.1% (range 2.7-93.5). The Spearman correlation test between the preinterventional dominant fibroid volume and percentage volume reduction showed a statistically significant, positive correlation (R = 0.33; p = 0.006).

Conclusions

The percentage volume reduction of intramural leiomyomas after UAE seems to be more pronounced in the case of larger tumors.

Predictive factors for pelvic magnetic resonance in response to arterial embolization of a uterine leiomyoma

OBJECTIVE

Minimally invasive methods are used as alternatives to treat leiomyomas and include uterine artery embolization, which has emerged as a safe, effective method. This study aims to evaluate the magnetic resonance imaging predictors for a reduction in leiomyoma volume in patients undergoing uterine artery embolization.

METHODS

This prospective longitudinal study was performed at a university hospital. We followed 50 symptomatic premenopausal women with uterine leiomyomas who underwent uterine artery embolization. We examined 179 leiomyomas among these patients. Magnetic resonance imaging was performed one month before and six months after uterine artery embolization. Two radiologists who specialized in abdominal imaging independently interpreted the images.

MAIN OUTCOME MEASURES

The magnetic resonance imaging parameters were the uterus and leiomyomas volumes, their localizations, contrast perfusion pattern and node-to-muscle ratio.

RESULTS

Six months after treatment, the average uterine volume reduction was 38.91%, and the leiomyomas were reduced by 55.23%. When the leiomyomas were submucosal and/or had a higher node-to-muscle ratio in the T2 images, the volume reduction was even greater (greater than 50%). Other parameters showed no association.

CONCLUSIONS

We conclude that symptomatic uterine leiomyomas in patients undergoing uterine artery embolization exhibit volume reductions greater than 50% by magnetic resonance imaging when the leiomyomas are submucosal and/or had a high node-to-muscle ratio in the T2 images.