Feasibility of ultrasound-guided high intensity focused ultrasound ablating uterine fibroids with hyperintense on T2-weighted MR imaging

Purpose

To retrospectively investigate whether uterine fibroids with hyperintense on pretreatment T2-weighted magnetic resonance imaging (MRI) could be treated with ultrasound-guided high intensity focused ultrasound (USgHIFU).

Materials and methods

282 patients with 282 symptomatic uterine fibroids who underwent USgHIFU treatment were retrospectively analyzed. Based on the signal intensity of T2-weighted MRI, uterine fibroids were classified as hypointense, isointense and hyperintense. Hyperintense fibroids were subjectively further subdivided into heterogeneous hyperintense, slightly homogeneous hyperintense and markedly homogeneous hyperintense based on the signal intensity of fibroid relative to myometrium and endometrium on T2-weighted MRI. Enhanced MRI was performed within one month after HIFU treatment. Non-perfused volume (NPV, indicative of successful ablation) ratio, treatment time, treatment efficiency, energy effect ratio and adverse events were recorded.

Results

The median volume of uterine fibroids was 70.3 cm³ (interquartile range, 41.1–132.5 cm³). The average NPV ratio, defined as non-perfused volume divided by the fibroid volume after HIFU treatment, was 76.8 ± 19.0% (range, 0–100%) in the 282 patients. It was 86.3 ± 11.9% (range, 40.9–100.0%) in the group with hypointense fibroids, 77.1 ± 16.5% (range, 32.2–100.0%) in isointense fibroids, and 67.6 ± 23.9% (range, 0–100.0%) in hyperintense fibroids. The lowest NPV ratio, lowest treatment efficiency, more treatment time, more sonication energy and pain scores were observed in the slightly homogeneous hyperintense fibroids, and the NPV ratio was 55.8 ± 26.7% (range, 0–83.9%) in this subgroup.

Conclusion

Based on our results, the heterogeneous and markedly homogeneous hyperintense fibroids were suitable for USgHIFU, and only the slightly homogeneous hyperintense fibroids should be excluded.     

Enhancing Ablation Effects of a Microbubble-Enhancing Contrast Agent (“SonoVue”) in the Treatment of Uterine Fibroids With High-Intensity Focused Ultrasound: A Randomized Controlled Trial

Purpose

To evaluate the role of the ultrasound contrast agent SonoVue in enhancing the ablation effects of ultrasound-guided high-intensity focused ultrasound (HIFU) on uterine fibroids.

Methods

Eighty patients with solitary uterine fibroids at a single center were randomly assigned to a control or SonoVue group. Of these, 40 were treated using HIFU alone; 40 who were pretreated with SonoVue received a bolus before the HIFU procedure. All patients underwent magnetic resonance imaging (MRI) scan before and after HIFU treatment.

Results

The post-HIFU MRI showed the nonperfused volume (NPV) in all of the treated uterine fibroids; the mean fractional ablation (NPV ratio) was 90.4 ± 8.3 % (range 66.4–100 %) in the SonoVue group and 82.8 ± 13.3 % (range 53.4–100 %) in the control group. The frequency of massive gray-scale changes that occurred during HIFU was greater in the group that received SonoVue than the group that did not. The average sonication time to reach massive gray-scale changes was significantly shorter in the group receiving SonoVue than the group without SonoVue. The acoustic energy for treating 1 mm³ of uterine fibroid was less in the SonoVue group than the control group. No any major complication occurred in this study.

Conclusion

Based on the results of this randomized controlled trial, SonoVue could be safely used to enhance the effects of HIFU treatment for uterine fibroids.     

Feasibility of magnetic resonance imaging-guided high intensity focused ultrasound therapy for ablating uterine fibroids in patients with bowel lies anterior to uterus

Purpose

To prospectively evaluate the feasibility of magnetic resonance (MR) imaging-guided high intensity focused ultrasound (HIFU) therapeutic ablation of uterine fibroids in patients with bowel lies anterior to uterus.

Materials and methods

Twenty-one patients with 23 uterine fibroids underwent MR imaging-guided high intensity focused ultrasound treatment, with a mean age of 39.4 ± 6.9 (20-49) years, with fibroids average measuring 6.0 ± 1.6 (range, 2.9-9.5) cm in diameter. After being compressed with a degassed water balloon on abdominal wall, MR imaging-guided high intensity focused ultrasound treatment was performed under conscious sedation by using fentanyl and midazolam. This procedure was performed by a Haifu^® JM focused ultrasound tumour therapeutic system (JM2.5C, Chongqing Haifu Technology Co., Ltd., China), in combination with a 1.5-Tesla MRI system (Symphony, Siemens, Germany), which provides real-time guidance and control. Contrast-enhanced MR imaging was performed to evaluate the efficacy of thermal ablation immediately and 3 months after HIFU treatment. The treatment time and adverse events were recorded.

Results

The mean fibroid volume was 97.0 ± 78.3 (range, 12.7-318.3) cm³. According to the treatment plan, an average 75.0 ± 11.4% (range, 37.8-92.4%) of the fibroid volume was treated. The mean fibroid volume immediately after HIFU was 109.7 ± 93.1 (range, 11.9-389.6) cm³, slightly enlarged because of edema. The average non-perfused volume was 83.3 ± 71.7 (range, 7.7-282.9) cm³, the average fractional ablation, which was defined as non-perfused volume divided by the fibroid volume immediately after HIFU treatment, was 76.9 ± 18.7% (range, 21.0-97.0%). There were no statistically significant differences between the treatment volume and the non-perfused volume. Follow-up magnetic resonance imaging (MRI) at 3 months obtained in 12 patients, the fibroid volume decreased by 31.4 ± 29.3% (range, −1.9 to 60.0%) in average, with paired t-test showing a statistically significant reduction (P = 0.002). The mean treatment time for ablating the average 83.3 ± 71.7 (range, 7.7-282.9) cm³ of fibroid volume was 2.5 ± 1.4 h (range, 27-390 min) in this study, which was relatively short and acceptable to patient and therapist. Four patients experienced mild skin burn (two with skin redness, two with blisters), the skin burn subsided within ∼2 days. No other adverse events were observed.

Conclusions

After the bowel was compressed with a degassed water balloon, MR imaging-guided high intensity focused ultrasound treatment is safe and feasible in ablating uterine fibroids in patients with bowel lies anterior to uterus.     

Volumetric MR-guided high-intensity focused ultrasound ablation of uterine fibroids: treatment speed and factors influencing speed

Objectives

To assess the treatment speed of volumetric magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) ablation of symptomatic uterine fibroids, with a focus on factors affecting treatment speed.

Methods

We received Institutional Review Board approval, and informed consent was obtained from all participants. Among 109 patients referred, 43 women (39.4 %) (mean age, 43.7 years), with 112 fibroids passed the screening. We treated 53 symptomatic uterine fibroids (47.3 %, 53/112) (volume, 341.2?±?256.5 ml) using volumetric MR-HIFU ablation. We assessed procedure times, non-perfused volume (NPV) and treatment speed (NPV/treatment time). We statistically analysed the factors affecting treatment speed using multiple logistic regression tests.

Results

Technical success was achieved in 42 of 43 cases. MR room time (from entrance to exit) and treatment time (from first to last sonication) were 216.0?±?40.6 min and 131.5?±?55.9 min, respectively. Immediate NPV was 178.9?±?147.3 ml, which was 57.4?±?25.5 % of the fibroid volume. Treatment speed was 81.8?±?48.0 ml/h. Multivariate analysis showed that a large fibroid volume (P?<?0.001), a low signal intensity ratio of fibroid to skeletal muscle on T2-weighted images (P?=?0.009) and timing after completion of the learning curve (P?<?0.001) significantly increased treatment speed.

Conclusion

Volumetric MR-HIFU ablation can effectively treat symptomatic uterine fibroids. The treatment speed appeared to improve when treating large and/or dark fibroids as well as upon completion of the learning curve.

Key Points

? High-intensity focused ultrasound (HIFU) offers another interventional radiological option for treating fibroids ? Volumetric MR-guided HIFU ablation can treat uterine fibroids in a timely fashion ? Treatment speed appeared to improve when treating large and/or dark fibroids ? Treatment speed appeared to improve upon completion of the learning curve     

Therapeutic response assessment of high intensity focused ultrasound therapy for uterine fibroid: utility of contrast-enhanced ultrasonography

PURPOSE: To assess the utility of contrast-enhanced ultrasonography (ceUS) in the assessment of the therapeutic response to high intensity focused ultrasound (HIFU) ablation in patients with uterine fibroid. MATERIALS AND METHODS: Sixty-four patients with a total of 64 uterine fibroids (mean: 5.3+/-1.2 cm; range: 3.2-8.9 cm) treated with HIFU ablation under the ultrasound guidance were evaluated with ceUS after receiving an intravenous bolus injection of a microbubble contrast agent (SonoVue) within 1 week after intervention. We obtained serial ceUS images during the time period from beginning to 5 min after the initiation of the bolus contrast injection. All of the patients underwent a contrast enhanced MRI (ceMRI) and ultrasound guided needle puncture biopsy within 1 week after HIFU ablation. And as a follow-up, all of the patients underwent US at 1, 3, 6 and 12 months after HIFU treatment. The volume change was observed and compared to pre- and post-HIFU ablation. The results of the ceUS were compared with those of the ceMRI in terms of the presence or absence of residual unablated tumor and pathologic change in the treated lesions. RESULTS: On ceUS, diagnostic accuracy was 100%, while residual unablated tumors were found in three uterine fibroids (4.7%) and failed treatment was found in eight uterine fibroids (12.5%). All the 11 fibroids were subjected to additional HIFU ablation. Of the 58 ablated fibroids without residual tumors on both the ceUS and ceMRI after the HIFU ablation, the volumes of all the fibroids decreased in different degrees during the 1 year follow-up USs. And histologic examinations confirmed findings of necrotic and viable tumor tissue, respectively. CONCLUSION: CEUS is potentially useful for evaluating the early therapeutic effect of percutaneous HIFU ablation for uterine fibroids.     

Outcome of uterine artery embolization versus MR-guided high-intensity focused ultrasound treatment for uterine fibroids: Long-term results

Objectives

To compare the long-term outcome after uterine artery embolization (UAE) versus magnetic resonance-guided high-intensity focused ultrasound (MR-g HIFU) for symptomatic uterine fibroids.

Methods

Seventy-seven women (median age, 39.3 years; range, 29.2–52.2 years) with symptomatic uterine fibroids, equally eligible for UAE and MR-g HIFU based on our exclusion criteria underwent treatment (UAE, N = 41; MR-g HIFU, N = 36) from 2002 to 2009 at our institution. Symptom severity (SS) and total health-related quality of life (Total HRQoL) scores were assessed by the uterine fibroid symptom and quality of life (UFS-QoL) questionnaire before treatment and at long-term follow-up after UAE (median 61.9 months) and after MR-g HIFU (median: 60.7 months). Re-intervention rates were assessed for each therapy and compared.

Results

Re-intervention was significantly lower after UAE (12.2%) than after MR-g HIFU (66.7%) at long-term follow-up (p < 0.001). After UAE changes in SS (50 pre-treatment vs. 6.3 post-treatment) and Total HRQoL (57.8 pre-treatment vs. 100 post-treatment) were significantly better than changes in SS (42.2 pre-treatment vs. 26.6 post-treatment) and Total HRQoL score (66.4 pre-treatment vs. 87.9 post-treatment) after MR-g HIFU (p = 0.019 and 0.049 respectively).

Conclusions

Improvement of SS and Total HRQoL scores was significantly better after UAE resulting in a significant lower re-intervention rate compared to MR-g HIFU.     

Effects of oxytocin on high intensity focused ultrasound (HIFU) ablation of adenomysis: A prospective study

Objective

To investigate the effects of oxytocin on high-intensity focused ultrasound (HIFU) ablation for the treatment of adenomyosis.

Materials and methods

Eighty-six patients with adenomyosis from three hospitals were randomly assigned to the oxytocin group or control group for HIFU treatment. During HIFU treatment, 80 units of oxytocin was added in 500 ml of 0.9% normal saline running at the rate of 2 ml/min (0.32 U/min) in the oxytocin group, while 0.9% normal saline was used in the control group. Both patients and HIFU operators were blinded to oxytocin or saline application. Treatment results, adverse effects were compared.

Results

When using oxytocin, the non-perfused volume (NPV) ratio was 80.7 ± 11.6%, the energy-efficiency factor (EEF) was 8.1 ± 9.9 J/mm³, and the sonication time required to ablate 1 cm³ was 30.0 ± 36.0 s/cm³. When not using oxytocin, the non-perfused volume ratio was 70.8 ± 16.7%, the EEF was 15.8 ± 19.6 J/mm³, and the sonication time required to ablate 1 cm³ was 58.2 ± 72.7 S/cm³. Significant difference in the NPV ratio, EEF, and the sonication time required to ablate 1 cm³ between the two groups was observed. No oxytocin related adverse effects occurred.

Conclusion

Oxytocin could significantly decrease the energy for ablating adenomyosis with HIFU, safely enhance the treatment efficiency.     

Effect of microbubble contrast agent during high intensity focused ultrasound ablation on rabbit liver in vivo

Objective

To evaluate the effect of a microbubble contrast agent (SonoVue) during HIFU ablation of a rabbit liver.

Materials and methods

HIFU ablations (intensity of 400 W/cm² for 4 s, six times, with a 5 s interval between exposures) were performed upon 16 in vivo rabbit livers before and after intravenous injection of a microbubble contrast agent (0.8 ml). A Wilcoxon signed rank test was used to compare mean ablation volume and time required to tissue ablation on real-time US. Shape of ablation and pattern of coagulative necrosis were analyzed by Fisher's exact test.

Results

The volume of coagulative necrosis was significantly larger in the combination microbubble and HIFU group than in the HIFU alone group (P < 0.05). Also, time to reach ablation was shorter in the combination microbubble and HIFU group than in the HIFU alone group (P < 0.05). When analyzing the shape of tissue ablation, a pyramidal shape was more prevalently in the HIFU alone group compared to the combination microbubble and HIFU group (P < 0.05). Following an analysis of the pattern of coagulative necrosis, non-cavitary necrosis was found in ten and cavitary necrosis in six of the samples in the combination microbubble and HIFU group. Conversely, non-cavitary necrosis occurred in all 16 samples in the HIFU alone group (P < 0.05).

Conclusion

HIFU of in vivo rabbit livers with a microbubble contrast agent produced larger zones of ablation and more cavitary tissue necrosis than without the use of a microbubble contrast agent. Microbubble contrast agents may be useful in tissue ablation by enhancing the treatment effect of HIFU.     

Targeted Vessel Ablation for More Efficient Magnetic Resonance-Guided High-Intensity Focused Ultrasound Ablation of Uterine Fibroids

Purpose

To report the first clinical experience with targeted vessel ablation during magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) treatment of symptomatic uterine fibroids.

Methods

Pretreatment T1-weighted contrast-enhanced magnetic resonance angiography was used to create a detailed map of the uterine arteries and feeding branches to the fibroids. A three-dimensional overlay of the magnetic resonance angiography images was registered on 3D T2-weighted pretreatment imaging data. Treatment was focused primarily on locations where supplying vessels entered the fibroid. Patients were followed 6?months after treatment with a questionnaire to assess symptoms and quality of life (Uterine Fibroid Symptom and Quality of Life) and magnetic resonance imaging to quantify shrinkage of fibroid volumes.

Results

In two patients, three fibroids were treated with targeted vessel ablation during MR-HIFU. The treatments resulted in almost total fibroid devascularization with nonperfused volume to total fibroid volume ratios of 84, 68, and 86%, respectively, of treated fibroids. The predicted ablated volumes during MR-HIFU in patients 1 and 2 were 45, 40, and 82?ml, respectively, while the nonperfused volumes determined immediately after treatment were 195, 92, and 190?ml respectively, which is 4.3 (patient 1) and 2.3 (patient 2) times higher than expected based on the thermal dose distribution. Fibroid-related symptoms reduced after treatment, and quality of life improved. Fibroid volume reduction ranged 31–59% at 6?months after treatment.

Conclusion

Targeted vessel ablation during MR-HIFU allowed nearly complete fibroid ablation in both patients. This technique may enhance the use of MR-HIFU for fibroid treatment in clinical practice.     

超声引导下经皮射频消融治疗黏膜下子宫肌瘤的有效性和安全性

 目的 探讨超声引导下经皮射频消融治疗黏膜下子宫肌瘤的有效性和安全性。方法 回顾性分析2016-03至2017-11收治的78例有症状的黏膜下子宫肌瘤,计算子宫肌瘤的完全消融率并评价治疗结果,比较术后3个月子宫肌瘤体积、血红蛋白(Hb)定量及子宫肌瘤症状及健康相关生活质量问卷(UFS-QOL)评分。观察和记录治疗过程中及治疗后随访期间患者出现的各种不良反应及并发症。结果 射频消融后3、6、9、12个月病灶体积缩小率分别为65.3%、75.6%、81.5%和91.6%。治疗3个月后,体积减少(35.1±9.7)cm³,血红蛋白增加(31.9±44.05 )g/L,UFS-QOL评分中SSS评分减少(24.7±13.2),HRQL评分增加(17.3±18.65),差异均有统计学意义(P＜0.01)。术后3 d检查未发现严重并发症。结论 超声引导下经皮射频消融治疗黏膜下子宫肌瘤是一种安全有效的治疗方法,适合对子宫保留有需求的患者。     

Comparison of clinical and MR imaging outcomes after uterine fibroid embolization with Bead Block and Embosphere

Purpose

To compare clinical and imaging outcomes after uterine fibroid embolization (UFE) with Embosphere versus Bead Block microspheres.

Materials and methods

Our institutional review board approved this HIPAA-compliant study. We conducted a retrospective review of all consecutive UFEs performed for symptomatic uterine fibroids at our academic institution from 2001 to 2008. UFE was performed using Embosphere (n = 70) or Bead Block (n = 55) microspheres. Patient symptoms and MR images were reviewed before and following UFE. The MR images were analyzed for changes in the size and contrast enhancement of the dominant fibroid and the uterus.

Results

125 patients underwent UFE. Pre-treatment characteristics (patient age, presenting symptoms, fibroid location, and volume of the largest fibroid) were similar across groups. Procedure endpoint (near-stasis, reached in 94% of cases), duration, and sedation medication doses were also similar. Clinical follow-up was available in 69 (55%) patients (mean duration: 13.6 months). Of these, 92% had clinical improvement of their main presenting symptom(s) and 3% developed early menopause. MRI follow-up was available in 105 (84%) patients (mean 7.8 months). Mean volume reduction of the largest fibroid was similar after Embosphere (48%) and Bead Block (53%, p = NS). Residual enhancement ≥5% in the dominant fibroid was similarly uncommon after Bead Block (19%) or Embosphere (16%, p = NS). Mean uterine volume reduction was similar across groups (38%); no myometrial infarction occurred.

Conclusion

This retrospective study showed no superiority of Embosphere over Bead Block microspheres in terms of clinical and imaging outcomes after UFE.     

Mid-term clinical efficacy of a volumetric magnetic resonance-guided high-intensity focused ultrasound technique for treatment of symptomatic uterine fibroids

Objective

To assess the mid-term efficacy of magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) using a volumetric ablation technique for treating uterine fibroids.

Methods

Forty-six premenopausal women with 58 symptomatic uterine fibroids were prospectively included for MR-HIFU. After treatment, CE-MRI allowed measurement of the non-perfused volume (NPV) ratio, defined as the non-enhancing part of the fibroid divided by fibroid volume. Clinical symptoms and fibroid size on T2W-MRI were quantified at 3 and 6 months’ follow-up. The primary endpoint was a clinically relevant improvement in the transformed Symptom Severity Score (tSSS) of the Uterine Fibroid Symptom and Quality of Life questionnaire, defined as a 10-point reduction.

Results

Volumetric ablation resulted in a mean NPV ratio of 0.40 ± 0.22, with a mean NPV of 141 ± 135 cm³. Mean fibroid volume was 353 ± 269 cm³ at baseline, which decreased to 271 ± 225 cm³ at 6 months (P?<?0.001), corresponding to a mean volume reduction of 29 % ± 20 %. Clinical follow-up showed that 54 % (25/46) of the patients reported a more than 10-point reduction in the tSSS. Mean tSSS improved from 50.9 ± 18.4 at baseline to 34.7 ± 20.2 after 6 months (P?<?0.001).

Conclusion

Volumetric MR-HIFU is effective for patients with symptomatic uterine fibroids. At 6 months, significant symptom improvement was observed in 54 % of patients.

Key Points

? Volumetric MR-guided high-intensity focused ultrasound is a novel ablation technique for leiomyomatosis. ? We prospectively evaluated the outcome of volumetric MR-HIFU ablation for symptomatic fibroids. ? This study showed that volumetric MR-HIFU results in an effective treatment. ? A randomised controlled trial would set this technique in an appropriate context.     

Findings of multidetector row computed tomography of HCCs treated by HIFU ablation

Purpose

We evaluated the efficacy of high-intensity focused ultrasound (HIFU) ablation for hepatocellular carcinoma (HCC), and a long-term study by follow-up multidetector-row computed tomography (CT) was conducted to evaluate the changes occurring in the treatment area following the HIFU ablation.

Materials and methods

HIFU ablation was carried out in 14 patients with small HCCs (≤3 lesions, ≤3 cm in diameter). The HIFU system (Chongqing Haifu Tech) was used under ultrasound guidance. The evaluations were performed by follow-up CT at 1 week, 1, 3, 6 and 12 months after the HIFU ablation.

Results

HIFU ablation was carried out successfully in 11 of the 14 patients. At 1 week after the HIFU, a peripheral rim enhancement was found in all cases (100%). This finding was persistent in 6 of the 11 cases (54.5%) at 1 month, and in 1 of the 11 (9%) cases at 3 months after HIFU ablation. In all cases, the rim enhancement disappeared by 6 or 12 months after the HIFU ablation. At the 12 months follow-up, a decrease in the diameter of the ablated lesions was found. The enhancement around the treated area was found to be persistent at the 12 months follow-up in the one case of recurrence of the treated site in which the safety margin was not sufficiently wide. During the follow-up period, there were 2 cases with residual of HCC tumors. We performed radiofrequency ablation (RFA) for these residual tumors after the HIFU ablation.

Conclusion

To ascertain the cause of the peripheral enhancement on follow-up CT images after the HIFU ablation, in particular, to determine whether it might be caused by residual tumor or recurrence at the treated site, careful follow-up is important, especially in cases where the safety margin of the ablated area was not sufficiently wide.     

Scaled Signal Intensity of Uterine Fibroids on T2-Weighted MR Imaging as a Predictor of the Potential Response to Uterine Fibroid Embolization

Purpose

To determine feasibility of scaled signal intensity (SSI) of uterine fibroids on T2-weighted magnetic resonance (MR) images to predict volume reduction rate (VRR) after uterine fibroid embolization (UFE).

Diffusion-weighted imaging properties of uterine fibroids pre- and post-uterine fibroid embolisation

Objective

To determine the change in apparent diffusion coefficient (ADC) of uterine fibroids following uterine fibroid embolisation (UFE), and if the ADC change correlates with either volume loss or degree of contrast enhancement post-UFE.

Materials and methods

This study was approved by our institutional review board with waiver of consent. The pelvic MRI examinations, including diffusion-weighted MRI (DWI) using 4 b-values, of 50 consecutive patients prior to and 6 months post-UFE were analyzed. The volume, ADC and amount of enhancement were calculated for each fibroid both pre- and post-UFE. The percent residual enhancement for each fibroid was categorized as either: no (0–1%) residual enhancement or residual (>1%) enhancement. Statistical analysis compared ADC, enhancement and volume for each fibroid pre- and post-UFE using paired t-tests and Pearson correlation coefficients.

Results

The mean ADC of all (n = 88) fibroids pre-UFE was 1.30 ± 0.20 × 10⁻³ mm²/s, and increased to 1.68 ± 0.24 × 10⁻³ mm²/s post-UFE (p < 0.0001). Lower pre-UFE ADC correlated with greater ADC change post-UFE (r = −0.50; p < 0.0001). There was no correlation between ADC change and volume change post-UFE (r = 0.07; p = 0.59). However, fibroids with no residual enhancement post-UFE had larger ADC change than those with residual enhancement (p = 0.003).

Conclusion

The ADC of fibroids rises post-UFE. ADC change post-UFE is associated with the degree of loss of enhancement and may therefore be valuable in predicting response to treatment in pre-procedural counseling.     

Laparoscopic Ultrasound-Guided Radiofrequency Ablation of Uterine Fibroids

Four patients with symptomatic uterine fibroids measuring less than 6 cm underwent laparoscopic ultrasound-guided radiofrequency ablation (RFA) using multiprobe-array electrodes. Follow-up of the treated fibroids was performed with gadolinium-enhanced magnetic resonance imaging (MRI) and patients’ symptoms were assessed by telephone interviews. The procedure was initially technically successful in 3 of the 4 patients and MRI studies at 1 month demonstrated complete fibroid ablation. Symptom improvement, including a decrease in menstrual bleeding and pain, was achieved in 2 patients at 3 months. At 7 months, 1 of these 2 patients experienced symptom worsening which correlated with recurrent fibroid on MRI. The third, initially technically successfully treated patient did not experience any symptom relief after the procedure and was ultimately diagnosed with adenomyosis. Our preliminary results suggest that RFA is a technically feasible treatment for symptomatic uterine fibroids in appropriately selected patients.     

Volumetric feedback ablation of uterine fibroids using magnetic resonance-guided high intensity focused ultrasound therapy

Objective

The purpose of this prospective multicenter study was to assess the safety and technical feasibility of volumetric Magnetic Resonance-guided High Intensity Focused Ultrasound (MR-HIFU) ablation for treatment of patients with symptomatic uterine fibroids.

Methods

Thirty-three patients with 36 fibroids were treated with volumetric MR-HIFU ablation. Treatment capability and technical feasibility were assessed by comparison of the Non-Perfused Volumes (NPVs) with MR thermal dose predicted treatment volumes. Safety was determined by evaluation of complications or adverse events and unintended lesions. Secondary endpoints were pain and discomfort scores, recovery time and length of hospital stay.

Results

The mean NPV calculated as a percentage of the total fibroid volume was 21.7%. Correlation between the predicted treatment volumes and NPVs was found to be very strong, with a correlation coefficient r of 0.87. All patients tolerated the treatment well and were treated on an outpatient basis. No serious adverse events were reported and recovery time to normal activities was 2.3?±?1.8?days.

Conclusion

This prospective multicenter study proved that volumetric MR-HIFU is safe and technically feasible for the treatment of symptomatic uterine fibroids.

Key Points

? Magnetic-resonance-guided high intensity focused ultrasound allows non-invasive treatment of uterine fibroids. ? Volumetric feedback ablation is a novel technology that allows larger treatment volumes ? MR-guided ultrasound ablation of uterine fibroids appears safe using volumetric feedback     

MRI T2WI信号强度与高强度聚焦超声消融子宫肌瘤疗效关系的研究

目的：通过研究消融前M RI T2 WI信号强度特点与高强度聚焦超声消融术（high intensity focused ultrasound ablation ,HIFU ）治疗子宫肌瘤消融疗效之间的关系,从信号方面探讨影响 HIFU 治疗子宫肌瘤疗效的因素。方法选择2011年10月～2013年7月经MRI诊断的子宫肌瘤患者50例,行超声引导下的 HIFU 治疗,共有子宫肌瘤56个,消融前根据M RI T2 WI信号强度将其分为四种类型：①高信号;②等信号;③低信号;④混杂信号,消融后次日及术后6个月行增强M RI扫描评估肌瘤体积的消融范围,计算消融率及术后6个月肌瘤体积的缩小率,分别作为早期和中期 HIFU疗效的指标,同时记录术中与消融有关的不良反应。结果所有患者顺利完成治疗,未出现显著并发症。消融前肌瘤的体积0.43～502．12cm3,平均（125．13±111．40）cm3,消融后次日增强M RI中无增强剂灌注区域体积0．38～316．63cm3,平均（87．09±78．05）cm3,消融率25．16％～97．92％,平均（70．61±15．62）％,且MRI T2WI不同信号强度之间疗效差异有统计学意义（P ＜0．05）,低信号强度的肌瘤消融率最高,6个月后此类肌瘤体积进一步缩小,且此缩小率与术后次日消融率呈正相关（ r ＝0．67,P ＜0．05）。结论 M RI T2 WI低信号子宫肌瘤更易达到理想的消融疗效,且术后肌瘤体积缩小程度较大,可为选择患者提供依据。     

Treatment failure after uterine artery embolization: prospective cohort study with multifactorial analysis of possible predictors of long-term outcome

Purpose

To evaluate the impact of baseline characteristics and residual leiomyoma perfusion after uterine artery embolization (UAE) on clinical long-term outcome.

Materials and methods

One hundred fifteen patients underwent UAE. All patients were divided into three groups according to achieved infarction rate determined on contrast-enhanced magnetic resonance imaging within 48–72 h after UAE (I: 100%, n = 60; II: 90–99%, n = 32; and III: 0–89%, n = 23). Treatment failure and subsequent re-interventions (surgery, repeat UAE) were assessed for each group and compared using Cox regression analysis (CRA) with respect to the following baseline variables: age, uterine and dominant fibroid volume, number of fibroids, location of largest fibroid, and clinical symptoms.

Results

Long-term follow-up was completed after a median of 7.2 years (range 5.1–9.6) with a response rate of 84%. CRA revealed that patients in group III had a 22.2-fold higher risk (p < 0.001) of treatment failure than patients in group I, whereas groups I and II did not differ significantly (p = 0.578). For patients with bleeding-related symptoms only, CRA showed a 5.1-fold higher risk (p = 0.025) of treatment failure than for patients with equally dominant bleeding- and bulk-related symptoms. A 40.5-fold higher likelihood (p < 0.001) of treatment failure was observed for patients in group III with bleeding-related symptoms only compared to those in group I with combined bleeding- and bulk-related symptoms.

Conclusion

Incomplete fibroid infarction after UAE is strongly associated with the risk of experiencing treatment failure. Patients with bleeding-related complaints only face the highest likelihood of treatment failure if UAE results in less than 90% fibroid devascularization.     

Expulsion of dominant submucosal fibroids after uterine artery embolization

Purpose

Purpose of this study was to evaluate the frequency, probability, and factors associated with expulsion of submucosal fibroids after uterine artery embolization (UAE) in addition to the technical and clinical results at 1-year follow-up.

Materials and methods

We determined the preinterventional volume of each dominant submucosal fibroid using the commonly used ellipsoid formula and a 3D volumetry in the MRI to define a threshold value in milliliters that indicates the probability for a fibroid expulsion. Assessment of fibroid expulsion was done by MRI at 3-month intervals for a year. Assessment of clinical mid term success was achieved by applying questionnaires at 1-year follow-up.

Results

Technical success was observed in all 20 patients (mean age of 41.4 ± 5.6 years; range: 29.2-51.1 years). Two (10%) minor and one (5%) major complications occurred. 10/20 dominant submucosal fibroids were completely expelled during the follow-up. Using 3D MRI volumetry the preinterventional mean volume of the later expelled fibroids was 56.8 ± 57.0 ml (range 2.3-198.0 ml) and the mean volume of non-expelled fibroids was 123.8 ± 147.3 ml (range 24.0-531.8 ml). This difference was statistically significant, but weak (p = 0.0494). Fibroids with a volume equal or less than the threshold value (66.0 ml) were 73% likely to be expelled and fibroids larger than 66.0 ml were 78% likely not to be expelled. All 20 patients demonstrated a significant reduction in the fibroid related symptoms.

Conclusion

In our study the complication rate was low despite increased rates of fibroid expulsion (50%); simultaneously the rate of treatment satisfaction was very high. Patients with a dominant submucosal fibroid under 66.0 ml should be informed about the probability of fibroid expulsion and the accompanying symptoms.