A Prediction of NPVR ≥ 80% of Ultrasound-Guided High-Intensity Focused Ultrasound Ablation for Uterine Fibroids

Effectiveness and complication rates of high intensity focused ultrasound treatment for abdominal wall endometriosis: A systematic review

In this review, a systematic literature search on the effectiveness and complication rates of ultrasound-guided and magnetic resonance-guided high-intensity focused ultrasound (USg-/MRgHIFU) for abdominal wall endometriosis (AWE) was conducted in six databases in May/June 2023. Original articles of (non)randomized trials, cohort studies, case-control studies and case series published in peer-reviewed journals were included. Of the included studies the level of evidence (LoE) and methodological quality using the ROBINS-I and IHE-QAT was assessed. Primary outcomes were non-perfused volume ratio (NPV%), lesion size, pain scores, side effects and complication rates according to Society of Interventional Radiology (SIR) guidelines. Secondary outcomes were recurrence and re-intervention rates. Seven cohort studies (one of good methodological quality) (LoE 3) on USgHIFU were included (n = 212, AWE lesions = 240-245). Six months after USgHIFU treatment, pain scores were reduced with 3.3-5.2 points (baseline: 5.1-6.8, n = 135). Self-limiting side effects were pain (85.7 % (114/133)) and swelling (34.6 % (46/133)) in the treatment area. Complications occurred in 17.7 % (32/181), all of which were minor. Recurrence occurred in 12.8 % (11/86). Three of these seven cohort studies compared USgHIFU (n = 61) with surgical excision (n = 74). Pooled results showed no significant differences in pain scores, complications (resp. 26.3 % (10/38) vs. 32.6 % (15/46) (p = 0.53)) and recurrences (resp. 4.9 % (3/61) vs. 5.4 % (4/74) (p = 0.90)). This systematic review suggests that HIFU is an effective and safe treatment option for AWE. USgHIFU treatment led to reduced pain scores and lesion size, was free of major complications and had a pooled recurrence rate of 12.8 %. Compared to surgical excision pooled results showed no significant differences in pain scores, complications and recurrences after USgHIFU. However, many of the included studies had limitations in their methodological quality and therefore the results should be interpreted with caution. Well-structured high-quality randomized controlled trials comparing HIFU to standard care should be conducted to provide more conclusive evidence.

The Predictive Effect of Quantitative Analysis of Signal Intensity Heterogeneity on T2-Weighted MR Images for High-intensity Focused Ultrasound Treatment of Uterine Fibroids

RATIONALE AND OBJECTIVES

To investigate whether the quantitative index of signal intensity (SI) heterogeneity on T2-weighted (T2W) magnetic resonance images can predict the difficulty and efficacy of high-intensity focused ultrasound (HIFU) ablation for uterine fibroids.

MATERIALS AND METHODS

The standard deviation (SD) of T2W image (T2WI) SI was used to quantify SI heterogeneity. The correlation between SD and the non-perfused volume ratio (NPVR) in 575 patients undergoing HIFU treatment was retrospectively analyzed, and the efficacy of SD in predicting NPVR was discussed. Three classifications were made based on the SD, and the ablation difficulty and ablation effect of different grades were compared. A total of 65 cases from another center were used as an external validation set to verify the classification performance of SD.

RESULTS

The SD of SI was negatively correlated with NPVR (r = -0.460, p < 0.001). The predictive efficiency of SD for the ablation effect was higher than that of the scaled signal intensity (0.767 vs. 0.701, p = 0.006). Univariate and multivariate logistic regression analyses showed that SD was an independent predictor of ablation effect. Based on SD, the three classifications were divided into SD I: SD < 101.0, SD II: 101.0 ≤ SD < 138.7, and SD III: SD≥ 138.7. The treatment time, sonication time, treatment intensity, and total energy of SD I were lower than those of SD II and III (p < 0.05).

CONCLUSION

The heterogeneity of T2WI SI of uterine fibroids is negatively correlated with NPVR. The SD of SI can be used to predict the ablation difficulty and ablation effect of HIFU.

Effects of high-intensity focused ultrasound combined with levonorgestrel-releasing intrauterine system on patients with adenomyosis

It is very important to treat adenomyosis which may cause infertility, menorrhagia, and dysmenorrhea for women at the reproductive age. High-intensity focused ultrasound (HIFU) is effective in destroying target tumor tissues without damaging the path of the ultrasound beam and surrounding normal tissues. The levonorgestrel-releasing intrauterine system (LN-IUS) is a medical system which is inserted into the uterine to provide medicinal treatment for temporary control of the symptoms caused by adenomyosis. This study was to investigate the effect of HIFU combined with the LN-IUS on adenomyosis. In the HIFU treatment, the parameters of the ultrasound were transmission frequency 0.8 MHz and input power 50-400 W (350 ± 30), and the temperature in the target tissue under these conditions would reach 60-100 °C (85 °C ± 6.3 °C). Size reduction and blood flow signal decrease were used to assess the effect of combined treatment. In this study, 131 patients with adenomyosis treated with HIFU combined with LN-IUS were retrospectively enrolled. The clinical and follow-up data were analyzed. After treatment, the volume of the uterine lesion was significantly decreased with an effective rate of 72.1%, and the adenomyosis blood flow signals were significantly reduced, with an effective rate of 71.3%. At six months, the menstrual cycle was significantly (P < 0.05) decreased from 31.4 ± 3.5 days before treatment to 28.6 ± 1.9 days, the menstrual period was significantly shortened from 7.9 ± 1.2 days before HIFU to 6.5 ± 1.3 days, and the menstrual volume was significantly (P < 0.05) decreased from 100 to 49% ± 13%. The serum hemoglobin significantly (P < 0.05) increased from 90.8 ± 6.2 g/L before treatment to 121.6 ± 10.8 g/L at six months for patients with anemia. Among seventy-two (92.3%) patients who finished the six-month follow-up, sixty-five (90.3%) patients had the dysmenorrhea completely relieved, and the other seven (9.7%) patients had only slight dysmenorrhea which did not affect their daily life. Adverse events occurred in 24 (18.3%) patients without causing severe consequences, including skin burns in two (1.5%) patients, skin swelling in four (3.1%), mild lower abdominal pain and low fever in 15 (11.5%), and subcutaneous induration in three (2.3%). Six months after treatment, no other serious side effects occurred in any patients with follow-up. In conclusions, the use of high-intensity focused ultrasound combined with the levonorgestrel-releasing intrauterine system for the treatment of adenomyosis is safe and effective even though the long-term effect remains to be confirmed.

Predicting the efficacy of high-intensity focused ultrasound (HIFU) ablation for uterine leiomyomas based on DTI indicators and imaging features

PURPOSE

To predict the efficacy of high-intensity focused ultrasound (HIFU) ablation for uterine leiomyomas based on diffusion tensor imaging (DTI) indicators and imaging features.

METHODS

Sixty-two patients with 85 uterine leiomyomas were consecutively enrolled in this retrospective study and underwent DTI scanning before HIFU treatment. Based on whether the non-perfused volume ratio (NPVR) was greater than 70%, all patients were assigned to sufficient ablation (NPVR ≥ 70%) or insufficient ablation (NPVR < 70%) groups. The selected DTI indicators and imaging features were incorporated to construct a combined model. The predictive performance of DTI indicators and the combined model were assessed using receiver operating characteristic (ROC) curves.

RESULTS

There were 42 leiomyomas in the sufficient ablation group (NPVR ≥ 70%) and 43 leiomyomas in the insufficient ablation group (NPVR < 70%). The fractional anisotropy (FA) and relative anisotropy (RA) values were higher in the sufficient ablation group than in the insufficient ablation group (p < 0.05). Conversely, the volume ratio (VR) and mean diffusivity (MD) values were lower in the sufficient ablation group than those in the insufficient ablation group (p < 0.05). Notably, the combined model composed of the RA and enhancement degree values had high predictive efficiency, with an AUC of 0.915. The combined model demonstrated higher predictive performance than FA and MD alone (p = 0.032 and p < 0.001, respectively) but showed no significant improvement compared with RA and VR (p > 0.05).

CONCLUSION

DTI indicators, especially the combined model incorporating DTI indicators and imaging features, can be a promising imaging tool to assist clinicians in predicting HIFU efficacy for uterine leiomyomas.

Comparison efficacy of ultrasound-guided HIFU for adenomyosis-associated dysmenorrhea with different signal intensity on T2-weighted MR imaging

AIM

To compare the therapeutic efficacy of ultrasound-guided high-intensity focused ultrasound (USgHIFU) in the treatment of adenomyosis with different signal intensity (SI) on T2-weighted images (T2WI).

METHODS

A total of 299 adenomyosis patients who underwent HIFU and completed a one-year follow-up were retrospectively reviewed. Based on the SI values of adenomyosis relative to myometrium and endometrium on T2WI MRI, the patients were classified into three groups: the hypointense adenomyosis (Hypo-AM) group, the isointense adenomyosis (Iso-AM) group, and the hyperintense adenomyosis (Hyper-AM) group. The non-perfused volume ratio (NPVr) and relief of dysmenorrhea were used to assess the therapeutic efficacy. Optimal cutpoints (CPs) of NPVr were determined using the postoperative dysmenorrhea score as an anchor. Logistic regression analysis was used to test the relationship between the NPVr and SI.

RESULTS

The clinical effectiveness rate was significantly lower in the Hyper-AM group than in the Hypo-AM and Iso-AM groups (P < 0.05 for both). The NPVr in the Hypo-AM and Iso-AM groups were significantly higher than that in the Hyper-AM group (P < 0.05 for both). The optimal CP was 54.0% for NPVr. Logistic regression analysis showed that the SI on T2WI was an effect factor for NPVr (P < 0.05), and the probability of NPVr ≥54.0% decreased continuously as the SI of adenomyosis increased.

CONCLUSIONS

The NPVr of 54.0% has a clinically significant impact on dysmenorrhea scores in patients. The efficiency of the Hypo-AM and Iso-AM was better than that of the Hyper-AM.

Long-term outcomes of ultrasound guided high intensity focused ultrasound ablation for patients with uterine fibroids classified by T2WI: a multicenter retrospective study

OBJECTIVE

To evaluate the long-term outcomes of ultrasound-guided high-intensity focused ultrasound (USgHIFU) ablation of uterine fibroids classified by T2-weighted magnetic resonance imaging (T2WI-MRI).

MATERIALS AND METHODS

The data of 1427 premenopausal women with symptomatic uterine fibroids who underwent USgHIFU at four teaching hospitals in China were analyzed retrospectively. The uterine fibroids were classified based on their T2WI-MRI signal intensities relative to that of skeletal muscle, myometrium and endometrium as: hypointense, isointense, heterogeneous hyperintense fibroids (HHF), slightly HHF (sHHF) and markedly HHF (mHHF), respectively. The rates of symptom relief and reintervention post-USgHIFU ablation were compared between the classified groups.

RESULTS

A total of 1303 patients were followed up for 44 (40, 49) months. The symptom relief rate of the hypointense and isointense fibroids was 83.3% and 79.5%, respectively, which were significantly higher (p < .05) compared to that of HHF, sHHF and mHHF (58.3%, 44.2% and 60.4%), respectively. sHHF had the lowest symptom relief rate (p < .05). The cumulative reintervention rate for hypointense, isointense, HHF, sHHF and mHHF types were 8.8%, 10.8%, 21.4%, 39.9% and 19.8%, respectively. The reintervention rate of hypointense/isointense fibroids was significantly lower than that of HHF/mHHF/sHHF (p < .01), while sHHF had the highest re-intervention rate (p < .01). Thus, reintervention rate is inversely correlated to the rate of symptom relief.

CONCLUSIONS

USgHIFU ablation is effective for hypointense, isointense, HHF and mHHF with acceptable long-term follow-up outcomes. However, sHHF is associated with a higher reintervention rate.

Prediction of postoperative reintervention risk for uterine fibroids using clinical-imaging features and T2WI radiomics before high-intensity focused ultrasound ablation

OBJECTIVE

To predict the risk of postoperative reintervention for uterine fibroids using clinical-imaging features and T2WI radiomics before high-intensity focused ultrasound (HIFU) ablation.

METHODS

Among patients with uterine fibroids treated with HIFU from 2019 to 2021, 180 were selected per the inclusion and exclusion criteria (42 reintervention and 138 non-reintervention). All patients were randomly assigned to either the training (n = 125) or validation (n = 55) cohorts. Multivariate analysis was used to determine independent clinical-imaging features of reintervention risk. The Relief and LASSO algorithm were used to select optimal radiomics features. Random forest was used to construct the clinical-imaging model based on independent clinical-imaging features, the radiomics model based on optimal radiomics features, and the combined model incorporating the above features. An independent test cohort of 45 patients with uterine fibroids tested these models. The integrated discrimination index (IDI) was used to compare the discrimination performance of these models.

RESULTS

Age (p < .001), fibroid volume (p = .001) and fibroid enhancement degree (p = .001) were identified as independent clinical-imaging features. The combined model had AUCs of 0.821 (95% CI: 0.712-0.931) and 0.818 (95% CI: 0.694-0.943) in the validation and independent test cohorts, respectively. The predictive performance of the combined model was 27.8% (independent test cohort, p < .001) and 29.5% (independent test cohort, p = .001) better than the clinical-imaging and radiomics models, respectively.

CONCLUSION

The combined model can effectively predict the risk of postoperative reintervention for uterine fibroids before HIFU ablation. It is expected to help clinicians to develop accurate, personalized treatment and management plans. Future studies will need to be prospectively validated.

Ultrasound-guided HIFU for uterine fibroids of hyperintense on T2-weighted MR imaging with or without GnRH-analogue-pretreated: A propensity score matched cohort study

Objective

To compare the therapeutic effect of high-intensity focused ultrasound (HIFU) ablation and HIFU pretreated with gonadotropin-releasing hormone analogue (GnRH-a) in the treatment of hyperintense uterine fibroids on T2-weighted magnetic resonance imaging (T2WI) by using propensity score matching.

Materials and methods

339 women with 368 hyperintense uterine fibroids on T2WI who underwent single-session HIFU ablation were enrolled, including 283 patients with 303 fibroids in the single-session HIFU (sHIFU) group and 56 patients with 65 fibroids in the HIFU pretreated with GnRH-a (Gn-HIFU) group. The signal intensity (SI) value and standard deviation (SD) value were measured based on T2WI, and the fibroids were further subdivided into heterogeneous hyperintense fibroids, slightly homogeneous hyperintense fibroids and markedly homogeneous hyperintense fibroids as 3 subgroups (HHF, sHHF and mHHF group respectively). Treatment time, sonication time, dose, non-perfused volume (NPV), NPV per sonication time, non-perfused volume ratio (NPVR), energy effect ratio (EEF) and adverse events were recorded.

Results

Out of 339 patients, the median NPVR was 75.2% (interquartile range,31.5%). After propensity score matching, the matched cohort included 91 (64.5%) patients in the sHIFU group and 48 (34.5%) patients in the Gn-HIFU group. The NPVR of sHHF in the Gn-HIFU group had significantly smaller than that in the sHIFU group (60.2% versus 74.9%, p = 0.005), and the NPVR of HHF in the Gn-HIFU group was higher than those in the sHIFU group (87.4% versus 72.9%, p = 0.002).

Conclusions

Compared with HIFU alone, the therapeutic efficacy of the heterogeneous hyperintense fibroids may be enhanced by GnRH-a pretreated with HIFU, however it is important to rule out the slightly homogeneous hyperintense fibroids.

Tolerance and efficacy of HIFU ablation for uterine fibroids NPVR ≥ 90%: a nested case-control study

OBJECTIVE

To investigate the tolerance and efficacy of HIFU ablation for uterine fibroids with a non-perfused volume ratio (NPVR) ≥ 90%.

METHODS

A prospective cohort study of 2411 patients from 20 clinical centers was available. Contrast-enhanced MRI was used to assess the non-perfused volume ratio (NPVR). The International Society of Interventional Radiotherapy (SIR) complication grading system was used as the tolerance index. Uterine Fibroids-related Symptoms-Quality of Life (UFS-QoL) was used to evaluate the efficacy.

RESULTS

A total of 1352 patients underwent USgHIFU ablation treatment enrolled, NPVR was median 91.9% (IQR, 81.4%,100.0%). There was 761 case (56.3%) in the NPVR ≥ 90% group in which 17.5% case experienced SIR-B abdominal pain, 591 cases (43.7%) in NPVR < 90% group in which 9.3% case had SIR-B abdominal pain. There were statistically differences in the improvement degree of UFS at 12 months among the four subgroups (NPVR < 70%, 70%-80%, 80%-90%, 90%-100%) (all p < 0.05).

CONCLUSIONS

Patients with NPVR ≥ 90% had a higher incidence of SIR-B lower abdominal pain. NPVR was positively correlated with the degree of symptom relief at 12 months, and NPVR ≥ 90% was more likely to obtain better clinical symptom relief.

Evaluation of physician experience in achieving non-perfused volume ratio of high-intensity focused ultrasound ablation for uterine fibroids: a multicentre study

Objective

To evaluate the effect of different levels of physician experience on the high-intensity focused ultrasound (HIFU) ablation of uterine fibroids and to provide a reference for the use of non-perfused volume ratio (NPVR) standards during training.

Methods

This prospective multicentre study enrolled patients with uterine fibroids. The effect of the physician’s level of experience on the outcomes under different NPVR standards and the learning curve of six centres without HIFU experience were analysed. The impact of patient demographic and clinical characteristics were also evaluated.

Results

A total of 1352 patients from 20 centres were included in the study. The median NPVRs were 92.00%, 88.10% and 92.86% in the no experience group, inexperienced group and experienced group, respectively. Posterior wall fibroids, lateral wall fibroids and fundus fibroids were inversely correlated with NPVR, while experienced physicians were positively correlated with NPVR. With NPVR ≥ 70% and NPVR ≥ 80% standards, physicians in the no experience group completed the learning curve on the 11th and 16th procedure, respectively. Physicians under a standard of an NPVR ≥ 90% did not complete the learning curve.

Conclusions

NPVR ≥ 80% is a standard that is worth using for HIFU treatment of uterine fibroids.

Physician Experience in Technical Success of Achieving NPVR ≥ 80% of High-Intensity Focused Ultrasound Ablation for Uterine Fibroids: A Multicenter Study

Objective

To evaluate the experience of the physician of the technical success in high-intensity focused ultrasound (HIFU) ablation of uterine fibroids with a nonperfused volume ratio (NPVR) of at least 80%.

Methods

Patients from a 20-center prospective study were enrolled in this study. In this study, among the 20 clinical centers, five centers had physician with >3 years of HIFU experience, and the other 15 centers initiated HIFU therapy <3 years, were defined as the experienced group and the inexperienced group, respectively. Technical success was defined as achieving NPVR ≥ 80% of uterine fibroids with no major complications and it was defined as the successful group; otherwise, it was defined as the unsuccessful group.

Results

A total of 1,352 patients were included at the age of 41.32 ± 5.08 years. The mean NPVR (87.48 ± 14.91%) was obtained in the inexperienced group (86.50 ± 15.76%) and in the experienced group (89.21 ± 13.12%), respectively. The multivariate analysis showed that the volume of uterus, location of fibroids, and physician experience were significantly correlated with technical success (p < 0.05). In the experienced group, 82.20% of uterine fibroids obtained NPVR ≥ 80%, compared with 75.32% in the inexperienced group, and the difference was significant (p = 0.003). The technical success rate of the experienced group was 82.00% which was higher than 75.20% of the inexperienced group (p = 0.004).

Conclusion

In technical success of achieving NPVR ≥ 80%, experience of the physician was positively correlated with technical success; NPVR and major complications for the inexperienced group were comparable to those of the experienced group from a clinical perspective; inexperienced physicians could reach NPVR ≥ 80% of sufficient ablation and were trustworthy in efficacy. Smaller uterus and fibroids of anterior wall were correlated with better technical success; experienced physicians still have better technical success when choosing patients with larger uterus, contributing to clinical decision-making and patient referral.

Comparison of Dose and Effectiveness of a Single-Session Ultrasound-Guided High-Intensity Focused Ultrasound Ablation of Uterine Fibroids With Different Sizes

PURPOSE

This study aimed to compare the dose and effectiveness of ultrasound-guided high-intensity focused ultrasound (USgHIFU) ablation of uterine fibroids with different sizes and explore the effect of uterine fibroid size on dose, which provided dose evaluation for clinicians in accordance with the size of uterine fibroids.

MATERIALS AND METHODS

A total of 1,000 patients with symptomatic uterine fibroids who received a single-session USgHIFU treatment were enrolled in this study. The size of fibroids was divided into seven groups: 3-4 cm, 4-5 cm, 5-6 cm, 6-7 cm, 7-8 cm, 8-9 cm, and 9-11 cm. The dose was expressed on the basis of the energy efficiency factor (EEF) as the energy required for ablation per unit volume of tissue, and the non-perfused volume ratio (NPVR) was used to assess the effect of HIFU ablation.

RESULTS

The median NPVR of 88.3% (IQR: 80.3%-94.8%) was obtained, and no significant difference was observed among the seven groups. The classification of T2-weighted image signal intensity fibroids in the 4-5 cm group was compared with that in the 6-7 cm and 8-9 cm groups, and the difference was significant (p < 0.05). However, the proportion of T2WI hyperintense signal fibroids had no significant difference among the seven groups (p > 0.05). The median EEF was 3.88 J/mm³, and a significant difference was observed among the seven groups of EEF (p < 0.05). The EEF of groups with a fibroid size less than 6 cm was more than double the EEF of groups with a fibroid size above 6 cm. In addition, the EEF of groups with a fibroid size of 4-5 cm and 3-4 cm was 3-4 times higher than those with a fibroid size above 7 cm (p < 0.05).

CONCLUSIONS

A single-session HIFU ablation for uterine fibroids of 3-11 cm can obtain an NPVR of more than 80%. The EEF decreased with the increase of the size of uterine fibroids. A fibroid size of 6.5 cm was considered as a clinical meaningful point affecting EEF.