Non-perfused Volume Research Articles

Robust Radiomics Models for Predicting HIFU Prognosis in Uterine Fibroids Using SHAP Explanations: A Multicenter Cohort Study.

This study sought to develop and validate different machine learning (ML) models that leverage non-contrast MRI radiomics to predict the degree of nonperfusion volume ratio (NVPR) of high-intensity focused ultrasound (HIFU) treatment for uterine fibroids, equipping clinicians with an early prediction tool for decision-making. This study conducted a retrospective analysis on 221 patients with uterine fibroids who received HIFU treatment and were divided into a training set (N = 117), internal validation (N = 49), and an external test set (N = 55). The 851 radiomics features were extracted from T2-weighted imaging (T2WI), and the max-relevance and min-redundancy (mRMR) and the least absolute shrinkage and selection operator (LASSO) regression were applied for feature selection. Several ML models were constructed by logistic regression (LR), decision tree (DT), random forest (RF), support vector machine (SVM), extreme gradient boosting (XGBoost), and light gradient boosting machine (LGBM). These models underwent internal and external validation, and the best model's feature significance was assessed via the Shapley additive explanations (SHAP) method. Four significant non-contrast MRI radiomics features were identified, with the SVM model outperforming others in both internal and external validations, and the AUCs of the T2WI models were 0.860, 0.847, and 0.777, respectively. SHAP analysis highlighted five critical predictors of postoperative NVPR degree, encompassing two radiomics features from non-contrast MRI and three clinical data indicators. The SVM model combining radiomics features and clinical parameters effectively predicts NVPR degree post-HIFU, which enables timely and effective interventions of HIFU.

Effect of “T2-rim sign” related parameters on high-intensity focused ultrasound ablation of uterine fibroids

PurposeTo investigate the effect of “high-signal-intensity peripheral rim on T2-weighted MR images (T2-rim sign)” related parameters on non-perfused volume ratio (NPVR) after high-intensity focused ultrasound (HIFU) ablation of uterine fibroids. MethodsData from 616 patients with uterine fibroids treated with HIFU were retrospectively analyzed. Univariate and multivariate logistic regression was used to analyze the factors influencing the ablation effect. The effect of T2-rim sign on ablation parameters and results was also analyzed. Spearman correlation analysis was used to compare the correlation between coverage ratio, average thickness of T2-rim sign and NPVR in 207 cases of fibroids with T2-rim sign. ResultsThe presence of T2-rim sign was an independent risk factor affecting the ablation effect. The coverage ratio of T2-rim sign was negatively correlated with treatment efficiency (r = -0.174, p = 0.012) and NPVR (r = -0.186, p = 0.007), and positively correlated with energy efficiency factor (EEF) (r = 0.156, p = 0.024). The average thickness of T2-rim sign was positively correlated with treatment intensity (r = 0.203, p = 0.003) and negatively correlated with NPVR (r = -0.363, p < 0.001). There was a negative correlation between the average thickness of the T2-rim sign and NPVR in isointense fibroids (r = -0.484, p < 0.001). ConclusionThe presence of T2-rim sign increases the difficulty of ablation and reduces the ablation effect. In clinical practice, the presence and related parameters of T2-rim sign should be fully considered when screening for HIFU indications and formulating treatment plans.

A novel scoring system based on magnetic resonance imaging for the prediction of the difficulty of ultrasound-guided high-intensity focused ultrasound ablation for uterine fibroids

Objective To develop a novel scoring system based on magnetic resonance imaging (MRI) for predicting the difficulty of ultrasound-guided high-intensity focused ultrasound (USgHIFU) ablation for uterine fibroids. Materials and methods A total of 637 patients with uterine fibroids were enrolled. Sonication time, non-perfused volume ratio (NPVR), and ultrasound energy delivered for ablating 1 mm3 of fibroid tissue volume (E/V) were each classified as three levels and assigned scores from 0 to 2, respectively. Treatment difficulty level was then assessed by adding up the scores of sonication time, NPVR and E/V for each patient. The patients with score lower than 3 were categorized into low difficulty group, with score equal to or greater than 3 were categorized into high difficulty group. The potential predictors for treatment difficulty were compared between the two groups. Multifactorial logistic regression analysis model was created by analyzing the variables. The difficulty score system was developed using the beta coefficients of the logistic model. Results Signal intensity on T2WI, fibroid location index, largest diameter of fibroids, abdominal wall thickness, homogeneity of the signal of fibroids, and uterine position were independent influencing factors for the difficulty of USgHIFU for uterine fibroids. A prediction equation was obtained: difficulty score = 17 × uterine position (anteverted =0, retroverted =1)+71 × signal intensity (hypointense = 0, isointense/hyperintense = 1) +8 × enhancement (homogenous = 0, heterogeneous = 1)+25×(largest diameter of fibroids-20) +35 × (fibroid location index −0.2) +1×(abdominal wall thickness −5). Conclusions This scoring system established based on MRI findings can be used to reliably predict the difficulty level of USgHIFU treatment of uterine fibroids.

High-intensity focused ultrasound ablation in the treatment of fumarate hydratase-deficient uterine leiomyoma

Objective This study aimed to explore the efficacy and safety of high-intensity focused ultrasound (HIFU) ablation for treating fumarate hydratase (FH)-deficient uterine leiomyomas. Method Ten patients with FH-deficient uterine leiomyomas treated with HIFU ablation at the Third Xiangya Hospital from July 2017 to January 2023 were enrolled in this study. The effectiveness and adverse effects of HIFU were analyzed. Results The median age of the patients who received HIFU was 32.0 years (range: 28–41 years). Only 2 patients had solitary uterine leiomyomas, whereas the remaining 8 patients had multiple uterine leiomyomas. The median diameter of the largest myoma was 56 mm (range: 41–99 mm). Magnetic resonance imaging showed that the FH-deficient uterine leiomyomas of 8 patients presented as mixed intensity on T2WI, that of one patient was hypointense, and that of another patient was hyperintense on T2WI. All patients successfully underwent HIFU ablation in one session without severe adverse effects. The median nonperfusion volume ratio (NPVR) was 40% (30.0%–78.0%) after HIFU treatment. Four patients had NPVR ≥70%. At 3-month follow-up after HIFU ablation, the clinical symptoms of 5 of the 8 patients with symptoms before treatment were relieved. Six months after treatment, 4 of the 8 patients with symptoms were still in remission. All patients received reintervention by March 2024. The reintervention rates were 20%, 70%, and 90% at 12, 24, and 36 months, respectively, after HIFU ablation. Conclusion HIFU is a safe and feasible treatment for FH-deficient uterine leiomyomas, and most patients show effective results in the short term after treatment. However, the reintervention rates are high, and the long-term effects are limited.

The value of susceptibility weighted imaging for immediate assessing the hyperacute outcome of MRgFUS ablation for uterine fibroids: a preliminary study

Purpose To investigate the value of susceptibility weighted imaging (SWI) for assessing the hyperacute outcome of ablation of uterine fibroids immediately after magnetic resonance-guided focused ultrasound (MRgFUS) treatment. Methods This retrospective imaging study included patients who underwent SWI and contrast-enhanced (CE) MR within 15 min of MRgFUS ablation for uterine fibroids. Two readers independently assessed the SWI features of ablative lesions and their association with the non-perfused volume (NPV) ratio. The intraclass correlation coefficient (ICC) and diagnostic value of SWI findings were calculated. Results A total of 27 uterine fibroids from 21 participants (mean age 40.1 ± 7.2 years) were analyzed. 51.9% (14/27) leiomyomas had NPV ratio ≥90%. In post-ablation SWI images, the interobserver ICC for the relative signal intensity and hypointense peripheral rim were 0.613 and 0.843, respectively (both p < .001). There was a significant difference in the prevalence of hypointense peripheral rim in leiomyomas with NPV ratio ≥90% and < 90% (p < .01), while the prevalence of relative signal intensity showed no significant difference (p > .05). When using the complete hypointense peripheral rim as a diagnostic criterion to identify NPV ratio ≥ 90%, readers 1 and 2 showed diagnostic sensitivity, specificity, and accuracy of 85.7%, 76.9%, 81.5%, and 78.6%, 76.9%, 77.8%, respectively. Conclusion Identifying a complete hypointense peripheral rim on SWI may be a potential imaging marker for assessing the hyperacute outcome of uterine fibroids ablation by MRgFUS, specifically in determining whether the NPV ratio is ≥90%.

Predicting the Prognosis of HIFU Ablation of Uterine Fibroids Using a Deep Learning-Based 3D Super-Resolution DWI Radiomics Model: A Multicenter Study

Rationale and ObjectivesTo assess the feasibility and efficacy of a deep learning based three-dimensional (3D) super-resolution diffusion-weighted imaging (DWI) radiomics model in predicting the prognosis of high-intensity focused ultrasound (HIFU) ablation of uterine fibroids. MethodsThis retrospective study included 360 patients with uterine fibroids who received HIFU treatment, including Center A (training set: N=240; internal testing set: N=60) and Center B (external testing set: N=60) and were classified as having a favorable or unfavorable prognosis based on the postoperative non-perfusion volume ratio. A deep transfer learning approach was used to construct super-resolution DWI (SR-DWI) based on conventional high-resolution DWI (HR-DWI), and 1198 radiomics features were extracted from manually segmented regions of interest in both image types. Following data preprocessing and feature selection, radiomics models were constructed for HR-DWI and SR-DWI using Support Vector Machine (SVM), Random Forest (RF), and Light Gradient Boosting Machine (LightGBM) algorithms, with performance evaluated using area under the curve (AUC) and decision curves. ResultAll DWI radiomics models demonstrated superior AUC in predicting HIFU ablated uterine fibroids prognosis compared to expert radiologists (AUC: 0.706, 95% CI: 0.647-0.748). When utilizing different machine learning algorithms, the HR-DWI model achieved AUC values of 0.805 (95% CI: 0.679-0.931) with SVM, 0.797 (95% CI: 0.672-0.921) with RF, and 0.770 (95% CI: 0.631-0.908) with LightGBM. Meanwhile, the SR-DWI model outperformed the HR-DWI model (P<0.05) across all algorithms, with AUC values of 0.868 (95% CI: 0.775-0.960) with SVM, 0.824 (95% CI: 0.715-0.934) with RF, and 0.821 (95% CI: 0.709-0.933) with LightGBM. And decision curve analysis further confirmed the good clinical value of the models. ConclusionDeep learning based 3D SR-DWI radiomics model demonstrated favorable feasibility and effectiveness in predicting the prognosis of HIFU ablated uterine fibroids, which was superior to HR-DWI model and assessment by expert radiologists.

Development and validation of a deep learning-based method for automatic measurement of uterus, fibroid, and ablated volume in MRI after MR-HIFU treatment of uterine fibroids

IntroductionThe non-perfused volume divided by total fibroid load (NPV/TFL) is a predictive outcome parameter for MRI-guided high-intensity focused ultrasound (MR-HIFU) treatments of uterine fibroids, which is related to long-term symptom relief. In current clinical practice, the MR-HIFU outcome parameters are typically determined by visual inspection, so an automated computer-aided method could facilitate objective outcome quantification. The objective of this study was to develop and evaluate a deep learning-based segmentation algorithm for volume measurements of the uterus, uterine fibroids, and NPVs in MRI in order to automatically quantify the NPV/TFL. Materials and MethodsA segmentation pipeline was developed and evaluated using expert manual segmentations of MRI scans of 115 uterine fibroid patients, screened for and/or undergoing MR-HIFU treatment. The pipeline contained three separate neural networks, one per target structure. The first step in the pipeline was uterus segmentation from contrast-enhanced (CE)-T1w scans. This segmentation was subsequently used to remove non-uterus background tissue for NPV and fibroid segmentation. In the following step, NPVs were segmented from uterus-only CE-T1w scans. Finally, fibroids were segmented from uterus-only T2w scans. The segmentations were used to calculate the volume for each structure. Reliability and agreement between manual and automatic segmentations, volumes, and NPV/TFLs were assessed. ResultsFor treatment scans, the Dice similarity coefficients (DSC) between the manually and automatically obtained segmentations were 0.90 (uterus), 0.84 (NPV) and 0.74 (fibroid). Intraclass correlation coefficients (ICC) were 1.00 [0.99, 1.00] (uterus), 0.99 [0.98, 1.00] (NPV) and 0.98 [0.95, 0.99] (fibroid) between manually and automatically derived volumes. For manually and automatically derived NPV/TFLs, the mean difference was 5% [-41%, 51%] (ICC: 0.66 [0.32, 0.85]). ConclusionThe algorithm presented in this study automatically calculates uterus volume, fibroid load, and NPVs, which could lead to more objective outcome quantification after MR-HIFU treatments of uterine fibroids in comparison to visual inspection. When robustness has been ascertained in a future study, this tool may eventually be employed in clinical practice to automatically measure the NPV/TFL after MR-HIFU procedures of uterine fibroids.

Feasibility, safety and efficacy of high intensity focused ultrasound ablation as a preoperative treatment for challenging hysteroscopic myomectomy

Purpose To investigate the feasibility, safety and efficacy of high intensity focused ultrasound ablation (HIFU) as a preoperative treatment for challenging hysteroscopic myomectomies. Materials and methods A total of 75 patients diagnosed with types 0–III of uterine fibroids were enrolled. Based on the Size, Topography, Extension of the base, Penetration and lateral Wall position (STEPW) classification scoring system, 25 cases with a score ≥ 5 points were treated with HIFU followed by hysteroscopic myomectomy (HIFU + HM group), whereas 50 cases with a score < 5 points were treated with hysteroscopic myomectomy (HM group). Results The median preoperative STEPW score was 7 in the HIFU + HM group and 2 in the HM group. The average non-perfused volume (NPV) ratio achieved in fibroids after HIFU was 86.87%. Patients in the HIFU + HM group underwent hysteroscopic myomectomy one to four days after HIFU, and downgrading was observed in 81.81% of fibroids. The operation time for patients in the HIFU + HM group was 73 min and the success rate of myomectomy in a single attempt was 60%. The volume of distention medium used during the operation was greater in the HIFU + HM group than in the HM group (15,500 ml vs. 7500 ml). No significant difference was observed between the two groups in terms of intraoperative blood loss, the incidence of intraoperative and postoperative complications, menstrual volume score, or uterine fibroid quality of life score. Conclusion HIFU can be utilized as a preoperative treatment for large submucosal fibroids prior to hysteroscopic myomectomy. HIFU offers a novel approach in the management of this subset of patients.

Achieving NPVR ≥ 80% as technical success of high-intensity focused ultrasound ablation for uterine fibroids: a cohort study

ObjectiveTo report the long-term re-intervention of patients with uterine fibroids after ultrasound-guided high-intensity focused ultrasound (USgHIFU) ablation and to analyse the influencing factors of re-intervention in patients in the NPVR ≥ 80% group.Materials and methodsPatients with a single uterine fibroid who underwent USgHIFU at our hospital from January 2012 to December 2019 were enrolled. The patients were divided into four groups according to different nonperfusion volume ratio (NPVR). Kaplan–Meier survival curve was used to analyse long-term re-intervention in different NPVR groups, and Cox regression was used to analyse the influencing factors of re-intervention in the NPVR ≥ 80% group.Main resultsA total of 1,257 patients were enrolled, of whom 920 were successfully followed up. The median follow-up time was 88 months, and the median NPVR was 85.0%. The cumulative re-intervention rates at 1, 3, 5, 8 and 10 years after USgHIFU were 3.4%, 11.8%, 16.8%, 22.6% and 24.1%, respectively. The 10-year cumulative re-intervention rate was 37.3% in the NPVR < 70% group, 31.0% in the NPVR 70–79% group, 18.2% in the NPVR 80–89% group and 17.8% in the NPVR ≥ 90% group (P < 0.05). However, no difference was found between the group of NPVR 80−89% and the group of NPVR ≥ 90% (P = 0.499). Age of patients and signal intensity on T2-weighted imaging (T2WI) of tumours were found to be independent risk factors for long-term re-intervention in the NPVR ≥ 80% group. A younger age and greater signal intensity on T2W images corresponded to a greater risk of re-intervention.ConclusionUSgHIFU, an alternative treatment for uterine fibroids, has reliable long-term efficacy. NPVR ≥ 80% can be used as a sign of technical success, which can reduce re-intervention rates. However, an important step is to communicate with patients in combination with the age of patients and the signal intensity on T2WI of fibroids.Trial registrationThis retrospective study was approved by the ethics committee at our institution (Registration No. HF2023001; Date: 06/04/2023). The Chinese Clinical Trial Registry provided full approval for the study protocol (Registration No. CHiCTR2300074797; Date: 16/08/2023).

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 ObjectiveTo 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 MethodsThe 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. ResultsThe 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). ConclusionThe 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.

Diffusion-weighted imaging as a potential non-gadolinium alternative for immediate assessing the hyperacute outcome of MRgFUS ablation for uterine fibroids.

The aim of this study was to investigate the value of diffusion-weighted imaging (DWI) as a potential non-gadolinium alternative for promptly assessing the hyperacute outcome of magnetic resonance-guided focused ultrasound (MRgFUS) treatment for uterine fibroids. In this retrospective study we included 65 uterine fibroids from 44 women, who underwent axial DWI (b-value: 800s/mm2) and contrast-enhanced (CE) MR within 15min post-ablation. Two blinded observers independently reviewed the DWI findings of ablated necrotic lesions and measured their volumes on DWI and CE images. The post-ablation DWI images revealed clear depiction of ablative necrotic lesions in all fibroids, which were classified into two types: the bull's eye sign (type 1) and the bright patch sign (type 2). The inter-observer intraclass correlation coefficient for classifying DWI signal types was 0.804 (p < 0.001). Volumetric analysis of ablated necrosis using DWI and CE T1-weighted imaging showed no significant variance, nor did the non-perfused volume ratios (all p > 0.05). Bland-Altman analysis revealed a mean difference of 2.38% and 1.71% in non-perfused volume ratios between DWI and CE, with 95% limits of agreement from - 19.06 to 23.82% and - 18.40 to 21.82%, respectively. The findings of this study support the potential of DWI as a viable non-gadolinium alternative for evaluating the hyperacute outcomes of MRgFUS ablation in uterine fibroids.

MR Diffusion-Weighted Imaging in Evaluating Immediate HIFU Treatment Response of Uterine Fibroids.

Nowadays, High Intensity Focused Ultrasound (HIFU) is a common surgery option for the treatment of uterine fibroids in China, the immediate response of which is clinically evaluated using Contrast Enhanced (CE) imaging. However, the injection of gadolinium with its potential adverse effect is of concern in CE and therefore, it deserves efforts to find a better imaging method without the need for contrast agent injection for this task. To assess the role of diffusion-weighted imaging (DWI) in evaluating the immediate therapeutic response of HIFU treatment for uterine fibroids in comparison with CE. 68 patients with 74 uterine fibroids receiving HIFU treatment were enrolled, and immediate treatment response was assessed using post-surgical DWI images. Semi-quantitative ordinal ablation quality grading and quantitative nonperfusion volume (NPV) measurement based on DWI and CE imaging were determined by two experienced radiologists. Agreement of ablation quality grading between DWI and CE was assessed using the weighted kappa coefficient, while intraobserver, interobserver and interprotocol agreements of NPV measurements within and between DWI and CE were evaluated using the intraclass correlation (ICC) and Bland-Altman analysis. Grading of immediate HIFU treatment response showed a moderate agreement between DWI and CE (weighted kappa = 0.446, p < 0.001). NPV measured in 65 fibroids with DWI of Grade 3~5 showed very high ICCs for the intraobserver and interobserver agreement within DWI and CE (all ICC > 0.980, p < 0.001) and also for the interprotocol agreement between DWI and CE (ICC = 0.976, p < 0.001). DWI could provide satisfactory ablation quality grading, and reliable NPV quantification results to assess immediate therapeutic responses of HIFU treatment for uterine fibroids in most cases, which suggests that non-contrast enhanced DWI might be potentially used as a more costeffective and convenient method in a large proportion of patients for this task replacing CE imaging.

Optimized treatment parameter by computer simulation for high-intensity focused ultrasound treatment of uterine adenomyosis: Short-term and long-term results.

This study aimed to investigate the efficacy and safety of using optimized parameters obtained by computer simulation for ultrasound-guided high-intensity focused ultrasound (HIFU) treatment of uterine adenomyosis in comparison with conventional parameters. We retrospectively assessed a single-institution, prospective study that was registered at Clinical Research Information Service (CRiS) of Republic of Korea (KCT0003586). Sixty-six female participants (median age: 44 years) with focal uterine adenomyosis were prospectively enrolled. All participants were treated with a HIFU system by using treatment parameters either for treating uterine fibroids (Group A, first 20 participants) or obtained via computer simulation (Group B, later 46 participants). To assess the treatment efficacy of HIFU, qualitative indices, including the clinically effective dysmenorrhea improvement index (DII), were evaluated up to 3 years after treatment, whereas quantitative indices, such as the nonperfused volume ratio and adenomyosis volume shrinkage ratio (AVSR), on MRI were evaluated up to 3 months after treatment. Quantitative/qualitative indices were compared between Groups A and B by using generalized linear mixed effect model. A safety assessment was also performed. Results showed that clinically effective DII was more frequently observed in Group B than in Group A (odds ratio, 3.69; P = 0.025), and AVSR were higher in Group B than in Group A (least-squares means, 21.61; P = 0.001). However, two participants in Group B developed skin burns at the buttock and sciatic nerve pain and required treatment. In conclusion, parameters obtained by computer simulation were more effective than the conventional parameters for treating uterine adenomyosis by using HIFU in terms of clinically effective DII and AVSR. However, care should be taken because of the risk of adverse events.

Preliminary insights into high-intensity focused ultrasound ablation for symptomatic uterine fibroids: a first look in Egypt

BackgroundUterine fibroids are common gynecological conditions that affect a significant number of women of reproductive age and may necessitate surgical intervention for their removal. However, there is a rising trend toward minimally invasive procedures, such as magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU) ablation. This report provides the first experience in Egypt and North Africa on the use of MRgHIFU ablation as a therapeutic option for uterine fibroids.ResultsThis study demonstrates a correlation between post-operative NPV% and symptom improvement. Following a three-month follow-up period, a significant reduction in pain scores and excessive bleeding was observed. Importantly, there was no significant elevation in hemoglobin levels (11.23 ± 2.23 to 11.25 ± 1.71 g/dL) after treatment. Furthermore, the mean non-perfused volume ratio in the treated fibroids was 46 ± 27.3% (SD) among the 20 participants. These findings suggest a favorable therapeutic outcome of MRgHIFU, with no serious adverse effects reported.ConclusionMRgHIFU is a noninvasive therapeutic approach for the treatment of uterine myomas, offering significant benefits in terms of pain reduction and improved quality of life. This particular study represents the pioneering clinical experience of this innovative therapy in Egypt.

Long-term re-intervention after USgHIFU and prediction of NPVR in different ages of patients with uterine fibroids

Objective Long-term re-intervention after ultrasound-guided high intensity focused ultrasound (USgHIFU) ablation was reported, and the prediction of non-perfusion volume ratio (NPVR) in differently aged patients with uterine fibroids (UFs) was explored. Materials and Methods Patients with UFs who underwent USgHIFU ablation from January 2012 to December 2019 were enrolled and divided into < 40-year-old and ≥ 40-year-old groups. Cox regression was used to analyze the influencing factors of re-intervention rate, and receiver operating characteristic (ROC) curve was used to analyze the correlation between NPVR and re-intervention rate. Results A total of 2141 patients were enrolled, and 1558 patients were successfully followed up. The 10-year cumulative re-intervention rate was 21.9%, and the < 40-year-old group had a significantly higher rate than the ≥ 40-year-old group (30.8% vs. 19.1%, p < 0.001). NPVR was an independent risk factor in both two groups. When the NPVR reached 80.5% in the < 40-year-old group and 75.5% in the ≥ 40-year-old group, the risk of long-term re-intervention was satisfactory. Conclusion The long-term outcome of USgHIFU is promising. The re-intervention rate is related to NPVR in differently aged patients. Young patients need a high NPVR to reduce re-intervention risk.

Non-contrast enhanced MRI for efficiency evaluation of high-intensity focused ultrasound in adenomyosis ablation

Objective To investigate the value of T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI) in evaluating the therapeutic effect of high-intensity focused ultrasound (HIFU) in adenomyosis ablation. Material and methods One hundred eighty-nine patients with adenomyosis were treated with HIFU. The ablation areas on T2WI and DWI sequences were classified into different types: type I, relatively ill-defined rim or unrecognizable; subtype IIa, well-defined rim with hyperintensity; subtype IIb, well-defined rim with hypointensity. The volume of ablation areas on T2WI (VT2WI) and DWI (VDWI) was measured and compared with the non-perfused volume (NPV), and linear regression was conducted to analyze their correlation with NPV. Results The VT2WI of type I and type II (subtype IIa and subtype IIb) were statistically different from the corresponding NPV (p = 0.004 and 0.024, respectively), while no significant difference was found between the VDWI of type I and type II with NPV (p = 0.478 and 0.561, respectively). In the linear regression analysis, both VT2WI and VDWI were positively correlated with NPV, with R 2 reaching 0.96 and 0.97, respectively. Conclusions Both T2WI and DWI have the potential for efficient evaluation of HIFU treatment in adenomyosis, and DWI can be a replacement for CE-T1WI to some extent.

A Non-Contrast Multi-Parametric MRI Biomarker for Assessment of MR-Guided Focused Ultrasound Thermal Therapies.

We present the development of a non-contrast multi-parametric magnetic resonance (MPMR) imaging biomarker to assess treatment outcomes for magnetic resonance-guided focused ultrasound (MRgFUS) ablations of localized tumors. Images obtained immediately following MRgFUS ablation were inputs for voxel-wise supervised learning classifiers, trained using registered histology as a label for thermal necrosis. VX2 tumors in New Zealand white rabbits quadriceps were thermally ablated using an MRgFUS system under 3 T MRI guidance. Animals were re-imaged three days post-ablation and euthanized. Histological necrosis labels were created by 3D registration between MR images and digitized H&E segmentations of thermal necrosis to enable voxel-wise classification of necrosis. Supervised MPMR classifier inputs included maximum temperature rise, cumulative thermal dose (CTD), post-FUS differences in T2-weighted images, and apparent diffusion coefficient, or ADC, maps. A logistic regression, support vector machine, and random forest classifier were trained in red a leave-one-out strategy in test data from four subjects. In the validation dataset, the MPMR classifiers achieved higher recall and Dice than a clinically adopted 240 cumulative equivalent minutes at 43 °C (CEM 43) threshold (0.43) in all subjects. The average Dice scores of overlap with the registered histological label for the logistic regression (0.63) and support vector machine (0.63) MPMR classifiers were within 6% of the acute contrast-enhanced non-perfused volume (0.67). Voxel-wise registration of MPMR data to histological outcomes facilitated supervised learning of an accurate non-contrast MR biomarker for MRgFUS ablations in a rabbit VX2 tumor model.

Prediction of non-perfusion volume ratio for uterine fibroids treated with ultrasound-guided high-intensity focused ultrasound based on MRI radiomics combined with clinical parameters

BackgroundPrediction of non-perfusion volume ratio (NPVR) is critical in selecting patients with uterine fibroids who will potentially benefit from ultrasound-guided high-intensity focused ultrasound (HIFU) treatment, as it reduces the risk of treatment failure. The purpose of this study is to construct an optimal model for predicting NPVR based on T2-weighted magnetic resonance imaging (T2MRI) radiomics features combined with clinical parameters by machine learning.Materials and methodsThis retrospective study was conducted among 223 patients diagnosed with uterine fibroids from two centers. The patients from one center were allocated to a training cohort (n = 122) and an internal test cohort (n = 46), and the data from the other center (n = 55) was used as an external test cohort. The least absolute shrinkage and selection operator (LASSO) algorithm was employed for feature selection in the training cohort. The support vector machine (SVM) was adopted to construct a radiomics model, a clinical model, and a radiomics–clinical model for NPVR prediction, respectively. The area under the curve (AUC) and the decision curve analysis (DCA) were performed to evaluate the predictive validity and the clinical usefulness of the model, respectively.ResultsA total of 851 radiomic features were extracted from T2MRI, of which seven radiomics features were screened for NPVR prediction-related radiomics features. The radiomics–clinical model combining radiomics features and clinical parameters showed the best predictive performance in both the internal (AUC = 0.824, 95% CI 0.693–0.954) and external (AUC = 0.773, 95% CI 0.647–0.902) test cohorts, and the DCA also suggested the radiomics–clinical model had the highest net benefit.ConclusionsThe radiomics–clinical model could be applied to the NPVR prediction of patients with uterine fibroids treated by HIFU to provide an objective and effective method for selecting potential patients who would benefit from the treatment mostly.

Long-term Efficacy of Fibroid Devascularization with Ultrasound-Guided High-Intensity Focused Ultrasound

High-intensity focused ultrasound (HIFU) has been increasingly used for treatment of uterine leiomyoma. The superiority of HIFU therapy targeting uterine leiomyoma blood vessels, however, still needs to be further explored. This study aims to evaluate the long-term efficacy of fibroid devascularization with ultrasound-guided HIFU (USgHIFU) and the effects of treatment on the ovarian reserve and endometrial injury. Fibroid devascularization was assessed with the Adler grade obtained by color Doppler flow imagingand power Doppler imaging (PDI). The targeted vessels were covered and then sonicated by HIFU focal spots. The patients were followed up at 1 month, 3 months, 6 months, 1 year, 2 years and 3 years after treatment. Adverse effects and complications were recorded. The non-perfusion volume rate (NPVR), fibroid volume shrinkage rate (FVSR), Adler Grade, symptom severity score (SSS) and uterine fibroid symptom and quality of life (UFS-QOL) were evaluated. Adverse events (AEs)were recorded. In Center 1, the enrolled patients completed the anti-Müllerian hormone (AMH) test before and at 6 months after treatment. A total of 117 eligible patients were consecutively enrolled to receive interventions and follow-up evaluations of the three centers from January 2019 to May 2023. The 1-month and 6-monthNPVRs were 66.60%±33.14% and 51.12%±39.84%, respectively. The mean FVSRs at 1 month and 6 months after treatment were 38.20% and 43.89%, respectively. No significant difference was observed in AMH levels before and after treatment (p>0.05). No irreversible endometrial injury was observed in MR images after HIFU treatment. No significant difference was observed in both 1-month and 6-monthFVSRs among Center 1, 2 and 3 (p>0.05). No severe AEs occurred. For long-term outcomes, significant differences were observed in Adler grade, FV, FVSR, SSS, reduction in SSSand UFS-QOL before and after treatment (p<0.001) whereas no significant difference was observed in Adler grade among 3 months, 1 year, 2 years and 3 years after treatment (p>0.05). The SSSs were reduced by 33.42% at 1 year, 42.32% at 2 years and 52.46% at 3 years after treatment. For patients with uterine fibroids, USgHIFU-induced devascularization is a safe and effective treatment option. It has little effect on ovarian function and the endometrial injury is reversible, which could be attractive for patients who plan to become pregnant.

Value of contrast-enhanced ultrasonography in microwave ablation treatment of symptomatic focal uterine adenomyosis.

This study evaluated the value of contrast-enhanced ultrasonography (CEUS) in the ultrasound-guided microwave ablation (MWA) treatment of symptomatic focal uterine adenomyosis. This retrospective study was conducted between March 2020 and January 2023, enrolling 52 patients with symptomatic focal uterine adenomyosis who had undergone MWA. All patients were examined with CEUS before and after MWA. The non-perfused volume (NPV) was compared between CEUS and dynamic contrast-enhanced magnetic resonance imaging (DCEMRI) following ablation. Therapeutic efficacy and safety were evaluated at 3-, 6-, and 12-month follow-ups. Additionally, this study explored the correlations between pre-treatment CEUS features and a volume reduction ratio indicating sufficient ablation, defined as 50% or more at the 3-month follow-up. No significant differences in NPV were noted between CEUS and DCE-MRI immediately after MWA and during follow-up (all P>0.05). At the 3-month follow-up, the median VRRs for the uterus and adenomyosis were 33.2% and 63.9%, respectively. Sufficient ablation was achieved in 69.2% (36/52) of adenomyosis cases, while partial ablation was observed in the remaining 30.8% (16/52). The identification of non-enhancing areas on pre-treatment CEUS was associated with sufficient ablation (P=0.016). At the 12-month follow-up, significant decreases were observed in both the uterine and adenomyosis volumes (all P<0.001). Dysmenorrhea and menorrhagia were significantly alleviated at 12 months, and no major complications were encountered. CEUS can be used to evaluate the ablation zone of focal adenomyosis that has been treated with MWA, similarly to DCE-MRI. The identification of non-enhancing areas on pretreatment CEUS indicates satisfactory treatment outcomes.