Updates on MR-Guided Focused Ultrasound for Symptomatic Uterine Fibroids

ACR Appropriateness Criteria® Management of Uterine Fibroids: 2023 Update

Uterine fibroids are the most common benign tumor in women of reproductive age and can present with symptoms including bleeding, bulk related symptoms, and infertility. Several treatment options are available for the management of uterine fibroids, including medical management, minimally invasive therapies such as uterine artery embolization and MR-guided focused ultrasound ablation, and surgical interventions ranging from laparoscopic myomectomy to open hysterectomy. Given this wide range of therapeutic interventions, it is important to understand the data supporting these interventions and to be able to apply it in different clinical settings. This document provides a summary of recent trials supporting various therapies for uterine fibroids, including recent evidence for MR-guided focused ultrasound ablation and a detailed discussion of fertility outcomes in myomectomy and uterine fibroid embolization. The American College of Radiology 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 where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Treatment of adenomyosis, abdominal wall endometriosis and uterine leiomyoma with interventional radiology: A review of current evidences

Interventional radiology shows promises in the field of women's health, particularly in pelvic interventions. This review article discusses the latest advancements in interventional radiology techniques for pelvic conditions affecting women including adenomyosis, abdominal wall endometriosis and uterine leiomyoma. Extraperitoneal endometriosis involving the abdominal wall may be treated by percutaneous thermal ablation, such as cryoablation, whereas uterine leiomyoma and adenomyosis can be managed either using percutaneous thermal ablation or using uterine artery embolization. Continued research and development in interventional radiology will further enhance the minimally-invasive interventions available for women's health, improving outcomes and quality of life for this large patient population of women.

Reduced-field of view three-dimensional MR acoustic radiation force imaging with a low-rank reconstruction for targeting transcranial focused ultrasound

PURPOSE

To rapidly image and localize the focus in MR-guided focused ultrasound (FUS) while maintaining a low ultrasound duty cycle to minimize tissue effects.

METHODS

MR-acoustic radiation force imaging (ARFI) is key to targeting FUS procedures such as neuromodulation, and works by encoding ultrasound-induced displacements into the phase of MR images. However, it can require long scan times to cover a volume of tissue, especially when minimizing the FUS dose during targeting is paramount. To simultaneously minimize scan time and the FUS duty cycle, a 2-min three-dimensional (3D) reduced-FOV spin echo ARFI scan with two-dimensional undersampling was implemented at 3T with a FUS duty cycle of 0.85%. The 3D k-space sampling scheme incorporated uniform undersampling in one phase-encoded axis and partial Fourier (PF) sampling in the other. The scan interleaved FUS-on and FUS-off data collection to improve displacement map quality via a joint low-rank image reconstruction. Experiments in agarose and graphite phantoms and living macaque brains for neuromodulation and blood-brain barrier opening studied the effects of the sampling and reconstruction strategy on the acquisition, and evaluated its repeatability and accuracy.

RESULTS

In the phantom, the distances between displacement centroids of 10 prospective reconstructions and a fully sampled reference were below 1 mm. In in vivo brain, the distances between centroids ranged from 1.3 to 2.1 mm. Results in phantom and in vivo brain both showed that the proposed method can recover the FUS focus compared to slower fully sampled scans.

CONCLUSION

The proposed 3D MR-ARFI reduced-FOV method enables rapid imaging of the FUS focus while maintaining a low FUS duty cycle.

Review of uterine fibroids: imaging of typical and atypical features, variants, and mimics with emphasis on workup and FIGO classification

Uterine fibroids are the most common gynecologic neoplasm. Although non-degenerated fibroids are easily identifiable on imaging, degenerated fibroids, fibroid variants, and fibroids with unusual growth patterns can constitute a diagnostic dilemma. Identification of these abnormal morphologic features can alter the diagnosis of presumed uterine fibroids and hence change management plans. This article reviews the typical and atypical radiologic imaging features of uterine fibroids, with an emphasis on the pitfalls, mimics, and radiologically identifiable features that can alter clinical management plans.

The efficacy and safety of MR-HIFU and US-HIFU in treating uterine fibroids with the volume <300 cm3: a meta-analysis

BACKGROUND

High-intensity focused ultrasound (HIFU) is a promising and non-invasive therapy for symptomatic uterine fibroids. Currently, the main image-guided methods for HIFU include magnetic resonance-guided (MR-HIFU) and ultrasound-guided (US-HIFU). However, there are few comparative studies on the therapeutic efficacy and safety of MR-HIFU and US-HIFU in treating symptomatic uterine fibroids with a volume <300 cm³.

OBJECTIVE

We performed this meta-analysis to evaluate the efficacy and safety of MR-HIFU and US-HIFU in treating symptomatic uterine fibroids with a volume <300 cm³.

METHODS

We searched relevant literature in PubMed, EMBASE, Cochrane Library CNKI from inception until 2021. The mean value, the proportion, and their 95% confidence intervals (CIs) were measured by random-effects models. Publication bias was assessed using funnel plots.

RESULTS

48 studies met our inclusion criteria-28 describing MR-HIFU and 20 describing US-HIFU. The mean non-perfused volume rate (NPVR) was 81.07% in the US-HIFU group and 58.92% in the MR-HIFU group, respectively. The mean volume reduction rates at month-3, month-6, and month-12 were 42.42, 58.72, and 65.55% in the US-HIFU group, while 34.79, 37.39, and 36.44% in the MR-HIFU group. The incidence of post-operative abdominal pain and abnormal vaginal discharge in the US-HIFU group was lower than that of MRI-HIFU. However, post-operative skin burn and sciatic nerve pain were more common in the US-HIFU group compared with MRI-HIFU. The one-year reintervention rate after MR-HIFU was 13.4%, which was higher than 5.2% in the US-HIFU group.

CONCLUSION

US-HIFU may show better efficiency and safety than MR-HIFU in treating symptomatic fibroids with a volume <300 cm³.

Magnetic resonance imaging parameters in predicting the ablative efficiency of high-intensity focused ultrasound for uterine fibroids

OBJECTIVE

To evaluate the role of quantitative MRI parameters in predicting HIFU ablation results for uterine fibroids.

MATERIAL AND METHODS

A total of 245 patients with uterine fibroids who underwent HIFU treatment in Chongqing Haifu Hospital were reviewed retrospectively. The patients were divided into two groups according to the non-perfused volume (NPV) ratio which was either higher or lower than 80%. The MRI parameters were measured, and a logistical regression analysis was performed to investigate the potential predictors associated with the NPV ratio. Receiver operating characteristics (ROC) analysis was used to determine the cut off value for MRI parameters in predicting a high NPV ratio.

RESULTS

The subcutaneous fat thickness in the group of patients with an NPV ratio over 80% was significantly thinner than that in the group of patients with an NPV ratio less than 80% (15 mm versus 21 mm). The signal intensity ratio of fibroids to skeletal muscle on T2WI was significantly lower in the group of patients with an NPV ratio over 80% compared with the group with an NPV ratio lower than 80% (2.46 versus 3.23). The signal intensity ratio of fibroid to skeletal muscle correlated negatively with the NPV ratio and positively with the energy efficiency factor (EEF). The cut off value of signal intensity ratio of fibroid to muscle for predicting the NPV ratio over 80% is 3.045.

CONCLUSION

The signal intensity ratio of fibroid to skeletal muscle on T2WI can be used as a factor for predicting the effectiveness of HIFU ablation of uterine fibroids.

Proton Resonance Frequency Shift Thermometry: A Review of Modern Clinical Practices

Magnetic resonance imaging (MRI) has become a popular modality in guiding minimally invasive thermal therapies, due to its advanced, nonionizing, imaging capabilities and its ability to record changes in temperature. A variety of MR thermometry techniques have been developed over the years, and proton resonance frequency (PRF) shift thermometry is the current clinical gold standard to treat a variety of cancers. It is used extensively to guide hyperthermic thermal ablation techniques such as high-intensity focused ultrasound (HIFU) and laser-induced thermal therapy (LITT). Essential attributes of PRF shift thermometry include excellent linearity with temperature, good sensitivity, and independence from tissue type. This noninvasive temperature mapping method gives accurate quantitative measures of the temperature evolution inside biological tissues. In this review, the current status and new developments in the fields of MR-guided HIFU and LITT are presented with an emphasis on breast, prostate, bone, uterine, and brain treatments. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY STAGE: 3.

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.

Role of Interventional Procedures in Obstetrics and Gynecology

Radiological guided intervention techniques are discussed in obstetric and gynecologic patients. Fallopian tube recanalization, postpartum hemorrhage control, techniques of treating uterine leiomyomas, pelvic congestion treatment, and the use of percutaneous and transvaginal ultrasonography-guided aspirations and biopsy are covered. These techniques use basic radiological interventional skills and show how they are adapted for use in the female pelvis.

Analysis of medication data of women with uterine fibroids based on data mining technology

The purpose of this study was to analyze the characteristics of the diagnosis and treatment of female uterine fibroids based on data mining technology and the medication rule. Clinical literature related to the treatment of uterine fibroids by Chinese National Knowledge Infrastructure (CNKI) from 2004 to 2018 were searched, and the literature meeting the requirements were selected according to the inclusion criteria and exclusion criteria. The contents of the prescription were recorded into the database, and the results of drug frequency, common drugs and core rules, etc. were obtained by the rule analysis of the software, so as to analyze the medication rules of modern doctors in treating uterine fibroids. Through research and analysis, it showed that common clinical drugs include leuprorelin (GnRH-a), danazol (androgen), gestrinone (progestin), mifepristone (progesterone receptor antagonist), and some cases of combination therapy. Based on the analysis of the frequency of drug, treatment effect and adverse drug reactions, it was found that the clinical application of mifepristone in the treatment of uterine fibroids was relatively common, with significant drug effect and mild adverse reactions, which was worthy of clinical promotion and application. Therefore, the results of this study provide a new basis for the clinical and basic research of traditional Chinese medicine in the treatment of uterine fibroids, but it still needs the verification of expert interpretation, experimental research and other methods.

Predictive Value of Quantitative Uterine Fibroid Perfusion Parameters From Contrast-Enhanced Ultrasound for the Therapeutic Effect of High-Intensity Focused Ultrasound Ablation

OBJECTIVES

To assess the predictive significance of quantitative perfusion parameters from contrast-enhanced ultrasound (CEUS) for the therapeutic response to high-intensity focused ultrasound (HIFU) ablation in patients with uterine fibroids.

METHODS

A total of 263 patients with single uterine fibroids were treated with HIFU ablation under ultrasound guidance. The arrival time, peak time, enhancement time, enhancement intensity, and enhancement rate were evaluated with pretreatment CEUS. According to a nonperfused volume ratio evaluation by posttreatment magnetic resonance imaging, all patients were assigned to groups with volume ratios of 70% or higher and lower than 70%. Then the predictive performances of different parameters for ablation efficacy were studied.

RESULTS

The arrival time, peak time, and enhancement time in the group with a nonperfused volume ratio of 70% or higher were longer than those in the group with a volume ratio lower than 70% (mean ± SD, 16.7 ± 3.5, 26.5 ± 4.9, and 10.2 ± 2.6 seconds, respectively, versus 13.3 ± 4.2, 20.8 ± 5.4, and 7.6 ± 2.3 seconds), whereas patients with a volume ratio of 70% or higher had a lower mean enhancement intensity and enhancement rate than those with a volume ratio lower than 70% (29.7 ± 16.7 dB and 3.2 ± 1.5 dB/s versus 63.2 ± 26.3 dB and 8.6 ± 4.3 dB/s; P < .05). The nonperfused volume ratio was negatively correlated with the enhancement intensity and enhancement rate (r = -0.631 and -0.712) but positively correlated with the arrival time, peak time, and enhancement time (r = 0.322, 0.456, and 0.477; P < .05). The areas under the receiver operating characteristic curve for the enhancement time, enhancement intensity, and enhancement rate were 0.73, 0.79, and 0.81 (P < .05).

CONCLUSIONS

Quantitative parameters from CEUS are potentially useful for evaluating the therapeutic effect of HIFU ablation for uterine fibroids.