Non-perfused Volume Ratio Research Articles

Volumetric magnetic resonance-guided high-intensity focused ultrasound ablation of uterine fibroids through abdominal scars: the impact of a scar patch on therapeutic efficacy and adverse effects

BackgroundTo retrospectively compare the treatment success, therapeutic efficacy, and adverse effects of magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU) treatment for uterine fibroid patients with and without abdominal scars.MethodsSeventy-six women who underwent treatment were divided into group 1 (patients with abdominal scars, which were covered with scar patches that prevents ultrasound energy from reaching the scar tissue immediately behind the patch) and group 2 (patients without abdominal scars). Non-perfused volume (NPV) ratios immediately after treatment, and fibroid volume reduction ratios and symptom severity scores (SSS) at the 6-months follow-up were assessed. All adverse effects were recorded.ResultsThe mean NPV ratios in groups 1 and 2 were 87.0 ± 14.1% and 91.5 ± 13.3%. At the 6-months follow-up, the fibroid volume reduction ratios in groups 1 and 2 were 0.45 ± 0.27 and 0.43 ± 0.21, and the corresponding improvement in mean transformed SSS were 0.7 ± 0.39 and 0.79 ± 0.28, respectively. No serious adverse effects were reported. The minor adverse effects encountered in this study are likely related to the temperature increase in the near-field of the ultrasound beam path, which inevitably leads to skin burns, or far-field heat absorption by distant bony structures (i.e., sciatic nerve symptoms), and are typically manifested inter-procedurally and resolved shortly thereafter.ConclusionsThe findings in this study suggest that the scar patch could be used safely and efficiently in MRgHIFU treatment for the patients with uterine fibroids and abdominal scars in the ultrasound beam path.

The role of T1 perfusion-based classification in predicting the outcome of magnetic resonance-guided high-intensity focused ultrasound treatment of adenomyosis

Objective: To assess the relationship between magnetic resonance (MR) T1 perfusion-based classification and the outcome of MR-guided high intensity focused ultrasound treatment of adenomyosis, defined as nonperfused volume (NPV) ratio.Methods: The adenomyosis of 31 women was classified into group A (time–signal intensity [SI] curve of adenomyosis lower than that of the myometrium) and group B (time–SI curve of adenomyosis equal to or higher than that of the myometrium) on the basis of time–SI curves on dynamic contrast enhanced (DCE) MR images acquired at screening. NPV ratios immediately after treatment and adenomyosis volume reduction ratios and symptom severity scores (SSS) at the six-month follow-up were retrospectively assessed. Univariate and multivariate analysis of pretreatment parameters conducted to assess independent factors impacting on immediate NPV ratio. All adverse effects were recorded.Results: The immediate NPV ratios in groups A and B were 89.2 ± 6.7% and 42.4 ± 19.0%, respectively. At the six-month follow-up, the adenomyosis volume reduction ratios in groups A and B were 0.27 ± 0.8 and 0.04 ± 0.1, respectively, with corresponding improvements of 0.7 ± 0.18 and 0.26 ± 0.25, respectively, in the mean transformed SSS. Univariate and multivariate analysis revealed that only T1 perfusion-based classification as an independent factor associated with the outcome of MR-guided high intensity focused ultrasound treatment. No serious adverse effects were reported.Conclusions: Our novel classification method introduced in this study might be clinically beneficial in classifying adenomyosis for predicting the immediate outcome of MR-guided high intensity focused ultrasound treatment.

High intensity focused ultrasound treatment of adenomyosis: The relationship between the features of magnetic resonance imaging on T2 weighted images and the therapeutic efficacy

ObjectivesTo investigate the relationship between the features of magnetic resonance imaging (MRI) on T2 weighted images (T2WI) and the therapeutic efficacy of high intensity focused ultrasound (HIFU) on adenomyosis. Materials and methodsFrom January 2011 to November 2015, four hundred and twenty-eight patients with symptomatic adenomyosis were treated with HIFU. Based on the signal intensity and the number of hyperintense foci in the adenomyotic lesions on T2WI, the patients were classified into groups. The day after HIFU ablation patients underwent contrast-enhanced MRI and a comparison was made of non-perfused volume (NPV) ratio, energy efficiency factor (EEF), treatment time, sonication time, and adverse effects. ResultsNo significant difference in terms of HIFU treatment settings and results was observed between the group of patients with hypointense adenomyotic lesions and the group with isointense adenomyotic lesions (P>0.05). However, the sonication time and EEF were significantly higher in the group with multiple hyperintense foci compared to the group with few hyperintense foci. The NPV ratio achieved in the lesions with multiple hyperintenese foci was significantly lower than that in the lesions with few hyperintense foci (P<0.05). No significant difference was observed in the rate of adverse effects between the two groups. ConclusionsBased on our results, the response of the adenomyotic lesions to HIFU treatment is not related to the signal intensity of adenomyotic lesions on T2WI. However, the number of the high signal intensity foci in the adenomyotic lesions on T2WI can be considered as a predictive factor to help select patients for HIFU treatment.

INFLUENCE OF QUANTITATIVE CHARACTERISTICS ON MRI-GUIDED FOCUSED ULTRASOUND ABLATION OF UTERINE FIBROIDS: THE POTENTIAL USE OF SIGNAL INTENSITY VALUES FROM FIBROID IN T2-WI AS A CRITERION FOR PATIENT SELECTION

Objective. To determine the effect of quantitative characteristics on the effectiveness of magnetic resonance imaging guided focused ultrasound (MRIgFUS) ablation of uterine fibroids and evaluate the possibility of their use for patient selection. Material and methods. Retrospective analysis of 67 FUS ablations (67 women, 94 fibroids) was performed. We evaluated the characteristics of fibroids (standardized signal intensity (SSI) and signal heterogeneity in T2-WI, the maximum diameter, the distance to the skin and to the sacrum during FUS, volume, nonperfused volume (NPV), MR-type), sonication energy and patients age. Standardization of the fibroid signal intensity was performed by using the signal intensity from iliac muscle. Correlation between NPV and quantitative characteristics was calculated. ROC-analysis was performed for determination of the optimal SSI threshold value required to achieve NPV≥50%. We evaluated the relation between MR-type of fibroids, NPV ratio and SSI. Results . Post treatment NPV ratio was 57.1 ± 22.5%. NPV for 1 type fibroids (n=67) was 63.4 ± 19.7%, for 2 type (n=20) – 46.8 ± ± 19.5% and for 3 type (n=7) – 26.4 ± 21%. Differences between groups was significant (p&lt;0.05). SSI showed significant correlation with NPV ratio (R=-0.28, p&lt;0.01). Significant correlation between NPV ratio and others quantitative characteristics was not detected. Fibroids with SSI≤1.4 characterized NPV≥50% (sensitivity 72.7%, specificity 71.4%, p&lt;0.01, AUC 0.72). MR-types of fibroids were characterized by different SSI (p&lt;0.05). SSI≤ 1/4 was characteristic only for 1 type fibroids. Conclusion. SSI can be used as an additional objective criterion for prediction of FUS results and patient selection. Good results of FUS (NPV≥50%) in most cases can be achieved for fibroids with SSI≤1.4.

EVALUATION OF FACTORS AFFECTING THE LONG-TERM RESULTS OF MAGNETIC RESONANCE IMAGING GUIDED FOCUSED ULTRASOUND ABLATION OF UTERINE FIBROIDS

Objective: to analyze the results of focused ultrasound ablation (MRgFUS) of uterine fibroids and to evaluate the factors affecting the long-term results of treatment. Material and methods. Retrospective analysis of 67 FUS ablations (67 women, 94 fibroids) was performed. The observation period after FUS was up to 36 months. Characteristics of fibroids (standardized signal intensity (SSI) and signal heterogeneity in T2-WI, maximum diameter, volume, nonperfused volume (NPV), coefficients of volume and NPV dynamics (CDV, CDNPV), MR-type) were assessed by MRI. Standardization of the fibroid signal intensity was performed by using the signal intensity from iliac muscle. CDV, CDNPV were calculated as the ratio of fibroids volume and NPV at the time of control MRI to their initial values. Results. Post treatment NPV ratio was 57.1 ± 22.5%. The maximal significant reduction of fibroids volume and NPV was detected by 12 months after FUS (52.1% and 85.8%). CDV and CDNPV showed significant (p&lt;0.05) correlation with post treatment NPV ratio (r=-0.5 and r=0.37), fibroids volume (r=0.28 and r=0.49) and maximum diameter (r=0.26 and r=0.49). Fibroids with NPV ≥50% and volume &lt;150 cm3 were characterized by the highest rate of volume reduction. Fibroids with NPV≥75% and volume &gt;100 cm3 were characterized by the lowest rate of NPV reduction. The maximal reduction of volume during the observation period was detected in fibroids with NPV≥75% and volume &lt;100 cm3, the minimal – in fibroids with NPV&lt;25% and volume &gt;150 cm3. Conclusion. The dynamics of fibroids volume and NPV after MRgFUS depends on initial values of these characteristics.

Pregnancy outcomes and symptom improvement of patients with adenomyosis treated with high intensity focused ultrasound ablation

Objective: To investigate the symptom improvement and pregnancy outcomes of patients with adenomyosis after treatment with high intensity focused ultrasound (HIFU) ablation. Methods: From October 2010 to October 2015, 68 patients with adenomyosis who wish to get pregnancies were treated with HIFU ablation in Suining Central Hospital. Among these patients, 56 presented with dysmenorrhea, 11 presented with menorrhagia, and 1 patient complained both; 41 of them had histories of abnormal pregnancy. The clinical data were analyzed retrospectively. Results: Fifty-four patients got pregnancy at the median of 10 months(range:1 to 31 months) after HIFU ablation, and 21 of them had delivered healthy babies. No uterine rupture occurred during gestation or delivery, and the newborn babies were healthy. Dysmenorrhea and menorrhagia in the patients who had pregnancies after HIFU ablation treatment were significantly relieved. The average menstruation volume score before and 1, 3, 6-month post-HIFU were 2.6±1.7, 1.7±0.8, 1.4±0.6, 1.3±0.6, respectively (P<0.05). The menstruation pain score before and 1, 3, 6-month after HIFU were 1.4±0.9, 0.9±0.7, 0.6±0.5, and 0.9±0.7, respectively (P<0.05). The volume of the adenomyotic lesions before and after HIFU at 1, 3, 6 month were (34±23), (23±15), (20±17), (20±12) cm3 (P<0.05). Although the spontaneous abortion rate was decreased after HIFU ablation treatment, there was no significant difference between the preoperative and postoperative [43% (23/54) versus 37% (20/54), P>0.05]. However, 20 of the 54 patients had spontaneous abortion, compared with 21 patients who had delivered babies, there were no significant statistical difference in terms of age, duration of disease, lesion size, non-perfused volume ratio, as well as the symptom scores before and after HIFU ablation treatment. Conclusions: HIFU ablation treatment is effective in improving symptoms of patients with adenomyosis. Based on our results, HIFU ablation treatment maybe also help to improve the pregnancy outcomes of patients with adenomyosis, but further studies are needed.

Safety of ultrasound-guided high-intensity focused ultrasound ablation for diffuse adenomyosis: A retrospective cohort study

ObjectivesTo evaluate the safety of ultrasound-guided high-intensity focused ultrasound (HIFU) ablation for patients with diffuse adenomyosis. MethodsThis was a retrospective cohort study. The data was collected from 417 symptomatic adenomyosis patients who underwent ultrasound-guided HIFU between January 2012 and December 2015 at 1st Affiliated Hospital of Chongqing Medical University, Chongqing, China. Among them were 260 patients with diffuse adenomyosis (Group D) and 157 patients with focal adenomyosis (Group F). All patients underwent contrast-enhanced magnetic resonance imaging (MRI) one week before and the day after HIFU treatment. Successful treatment with HIFU was measured by the non-perfused volume ratio (NPVR). Intraprocedural and postprocedural adverse effects and complications were recorded to assess the safety of the procedure. Patients were followed-up for three months post-treatment. Complications were given a grade A through F according to the SIR Standards. ResultsAll patients successfully completed the procedure, non-perfused regions appeared in 415 (99.5%) patients. The non-perfused volume ratio (NPVR) of Group D was significantly lower than that of Group F (P<0.05). During the procedure, the odds ratio of skin-burning pain was 1.7 (OR=1.617, 95% CI: 1.103–2.532), when comparing Group D with Group F, while the odds ratio of inguinal pain was equal to 2.0 (OR=2.038, 95% CI: 1.161–3.580), when Group F was compared to Group D. 97 patients (23.3%) received nominal therapy due to complications ([Society of interventional radiology, SIR]-B grade), among them, there were 62 cases (23.8%) in Group D and 35 cases (22.3%) in Group F. No significant difference was found between the two groups (P>0.05) and neither of the reported complications of SIR-C-SIR-F occurred within the two groups. ConclusionsBased on our results, ultrasound-guided HIFU is safe for the treatment of diffuse adenomyosis, and controlling the ablation zone is crucial to ensure patients’ safety.

Magnetic resonance texture parameters are associated with ablation efficiency in MR-guided high-intensity focussed ultrasound treatment of uterine fibroids

Objectives: The objective of this study is to assess the association between texture parameter analysis derived from T2-weighted images and efficiency of magnetic resonance-guided focussed ultrasound (MRgFUS) ablation for the treatment of uterine fibroids.Materials and methods: Fifty-five women treated by MRgFUS were included in this retrospective analysis. Texture parameters were calculated using three 2D regions of interest placed on three consecutive slices on the same sagittal 3D T2-weighted images obtained at the beginning of MRgFUS ablation. Using uni- and multi-variate linear regression, texture parameters, fibroids/muscular T2W ratio (T2Wr), Funaki type, and fibroid depth were correlated with ablation efficiency, defined as the ratio of non-perfused volume (NPV) on post-treatment contrast-enhanced MRI by total volume of treatment-cell sizes used. Inter-rater reproducibility for texture analysis was assessed using variation coefficients.Results: The mean total treatment cell volume was 49.5 (±30) ml, corresponding to a mean NPV of 57.2 (±57) ml (28%). The mean ablation efficiency was 1.14 (±0.7), with a range of 0.03–3.6. In addition to fibroid/muscular T2Wr, seven of the 14 texture parameters were significantly correlated with ablation efficiency: mean signal intensity (p = .047); Skewness (p = .03); Kurtosis (p = .015); mean uniformity (p = .052); mean sum of square (p = .045); mean sum entropy (p = .021) and mean entropy (p = .051). In multivariate linear regression, fibroid/muscular T2Wr and sum of entropy were associated with ablation efficiency. The inter-rater coefficient of variation for sum entropy was 2.6%.Conclusions: Uterine fibroid texture parameters provide complementary information to T2Wr, and are associated with MRgFUS efficiency.Key pointsMean sum entropy is negatively correlated with MRgFUS efficiency (ρ = −0.307, p = .021).Fibroids/muscular T2-weighted ratio and entropy are associated with MRgFUS efficiency.Texture parameters are better predictors of MRgFUS efficiency than Funaki type.Fibroid MR texture analysis can improve patient selection for MRgFUS.

A retrospective study of magnetic resonance-guided focused ultrasound ablation for uterine myoma in Taiwan

ObjectiveTo report our experiences with 40 patients who were treated with magnetic resonance-guided focused ultrasound surgery (MRgFUS) for uterine fibroids and their 6-month follow-up status. Materials and MethodsA total of 40 patients with uterine fibroids underwent MRgFUS from January 2009 to November 2011. The Uterine Fibroid Symptoms and Quality of Life Questionnaire was used to determine the patients' Symptom Severity Scores (SSS) prior to and 6 months after treatment. The nonperfused volume (NPV) values and NPV ratio were obtained immediately at the end of the treatment and at 6 months follow-up. ResultsNo procedure-related complications were noted throughout the 6-month follow-up period among the 40 patients who underwent MRgFUS for uterine fibroids. The mean reduction in SSS in our patients after 6 months was 43.7%, and the mean reduction of fibroid volume was 31.7%. In addition, the mean reduction of NPV and mean NPV ratio was 52.7% and 33.3%, respectively. ConclusionThe results obtained from this study demonstrated that MRgFUS can be safely and effectively used to ablate uterine fibroids to produce a significant decrease in mean fibroid volume and improve SSS for up to 6 months after treatment.

A comparison of ultrasound-guided high intensity focused ultrasound for the treatment of uterine fibroids in patients with an anteverted uterus and a retroverted uterus

Objective: The aim of this study was to compare the treatment outcomes of ultrasound-guided high-intensity focused ultrasound (USgHIFU) for uterine fibroids in patients with an anteverted uterus versus a retroverted uterus.Materials and methods: Based on the principles of statistics we enrolled 221patients with an anteverted uterus and 221 with a retroverted uterus. All patients had a solitary uterine fibroid and every fibroid was identified as hypointense on the T2 weighted images (T2WI) on magnetic resonance. The baseline characteristics of the patients, treatment results and adverse events were compared between the two groups.Results: There were no significant differences in baseline characteristics between the two groups. The average non-perfused volume ratio of fibroids was 85.2 ± 18.7% in the group of patients with a retroverted uterus, while it was 87.7 ± 11.8% in patients with an anteverted uterus (P < 0.05). The fibroids in patients with a retroverted uterus were treated using lower sonication power and longer sonication time. During the procedure patients with a retroverted uterus had a higher incidence of sciatic/buttock pain and groin pain, while patients with an anteverted uterus complained of lower abdominal pain or a burning sensation on the skin. Immediately after USgHIFU, the rates of sciatic/buttock pain and skin burn were significantly higher in patients with a retroverted uterus.Conclusion: The results of this study indicated that uterine fibroids with hypointensity on T2WI in a retroverted uterus can be safely and effectively treated with USgHIFU. However, the fibroids in an anteverted uterus are easier to treat with USgHIFU.

Factors influencing the ablative efficiency of high intensity focused ultrasound (HIFU) treatment for adenomyosis: A retrospective study

Objectives The aim of this study was to investigate factors affecting ablative efficiency of high intensity focused ultrasound (HIFU) for adenomyosis. Materials and methods In all, 245 patients with adenomyosis who underwent ultrasound guided HIFU (USgHIFU) were retrospectively reviewed. All patients underwent dynamic contrast-enhanced magnetic resonance imaging (MRI) before and after HIFU treatment. The non-perfused volume (NPV) ratio, energy efficiency factor (EEF) and greyscale change were set as dependent variables, while the factors possibly affecting ablation efficiency were set as independent variables. These variables were used to build multiple regression models. Results A total of 245 patients with adenomyosis successfully completed HIFU treatment. Enhancement type on T1 weighted image (WI), abdominal wall thickness, volume of adenomyotic lesion, the number of hyperintense points, location of the uterus, and location of adenomyosis all had a linear relationship with the NPV ratio. Distance from skin to the adenomyotic lesion’s ventral side, enhancement type on T1WI, volume of adenomyotic lesion, abdominal wall thickness, and signal intensity on T2WI all had a linear relationship with EEF. Location of the uterus and abdominal wall thickness also both had a linear relationship with greyscale change. Conclusion The enhancement type on T1WI, signal intensity on T2WI, volume of adenomyosis, location of the uterus and adenomyosis, number of hyperintense points, abdominal wall thickness, and distance from the skin to the adenomyotic lesion’s ventral side can all be used as predictors of HIFU for adenomyosis.

Clinical Predictors of Long-term Success in Ultrasound-guided High-intensity Focused Ultrasound Ablation Treatment for Adenomyosis: A Retrospective Study.

The long-term outcomes of ultrasound-guided high-intensity focused ultrasound (USgHIFU) ablation treatment for adenomyosis and the relevant factors affecting the durability of symptom relief were assessed in this study.A total of 230 women with adenomyosis who were treated with USgHIFU ablation between January 2007 and December 2013 were retrospectively analyzed. The contrast-enhanced ultrasonography (CEUS) was performed immediately after the treatment to evaluate the ablation effect, and the nonperfused volume (NPV) ratio was then calculated. Regular follow-up was conducted and the visual analog scale (VAS) score was used to assess the changes in dysmenorrhea. The effect of treatment was evaluated after an average follow-up length of 3 months and the factors affecting clinical success and symptom relapse were identified.Of the 230 treated patients, 208 (90.4%) were followed up regularly, with a median follow-up length of 40 months (range, 18–94 months). Mean value of the NPV ratio calculated immediately after the treatment was 57.4 ± 24.4%. Varying degrees of symptomatic relief of dysmenorrhea based on the VAS scores were observed in 173 (83.2%) patients and 71.0% of the patients were asymptomatic during follow-up. Women with higher NPV ratio (OR = 0.964, 95% CI = 0.947–0.982, P = 0.000) and older age (OR = 0.342, 95% CI = 0.143–0.819, P = 0.016) were more likely to achieve clinical success. Dysmenorrhea recurred in 45 (26%) out of 173 cases; the median recurrence time was 12 months after treatment. The lower BMI (OR = 1.221, 95% CI = 1.079–1.381, P = 0.001) and the higher acoustic power (OR = 0.992, 95% CI = 0.986–0.998, P = 0.007) were associated with less risk of relapse. Twelve of the 14 patients who were retreated by USgHIFU ablation after experiencing dysmenorrhea recurrence achieved clinical success.USgHIFU ablation is an effective uterus-conserving treatment for symptomatic adenomyosis with an acceptable long-term success rate. Higher chance of clinical success can be achieved in patients with larger NPV ratio and older age, whereas higher BMI and lower acoustic power may result in a higher chance of recurrence. These factors are helpful in selecting suitable patients for USgHIFU and in predicting the durability of symptom relief.

Clinical Consideration of Treatment to Ablate Uterine Fibroids with Magnetic Resonance Imaging-guided High Intensity Focused Ultrasound (MRgFUS): Sonalleve.

ObjectivesMagnetic resonance imaging (MRI)-guided high intensity focused ultrasound surgery (MRgFUS) is a newly emerging non-invasive technique for the treatment of uterine fibroids. The purpose of this study is to review the clinical impact of MRgFUS.MethodsThis study examined 157 patients. The high intensity focused ultrasound (HIFU) utilized in this study was Philips Achieva 1.5 Tesla MR (Philips Healthcare, Best, the Netherlands) and Sonalleve HIFU system. The patients were followed in post-operative Month 1, Month 3, and Month 6 to investigate any change. Then, these were further classified according to the use of uterine stimulant (oxytocin) in parallel, Funaki Type of uterine fibroid, HIFU intensity, and non-perfused volume (NPV) ratio.ResultsWhen the uterine stimulant was utilized, the HIFU intensity was measured at significantly lower levels, compared with the group not using uterine stimulant, and treatment duration was significantly. The NPV ratio was found significantly higher in the group using uterine stimulant. Concerning the correlation between Funaki Type of uterine fibroid and average sonication power, it was found that the closer to Type I, the lower the sonication power, the shorter the treatment duration, and the higher the NPV ratio significantly.ConclusionsIn this study, it was found that the lower the Funaki Types of uterine fibroids, and the higher the NPV ratio immediately after the operation, the larger the uterine fibroid volume decrease and SSS change were. Also, if uterine stimulant was used in parallel in treatment, treatment duration and HIFU intensity could become shorter and lower.

Dynamic contrast-enhanced MRI serves as a predictor of HIFU treatment outcome for uterine fibroids with hyperintensity in T2-weighted images.

The aim of the present study was to investigate the efficacy of dynamic contrast-enhanced magnetic resonance imaging (MRI) in predicting the outcome of using ultrasound-guided high-intensity focused ultrasound (USgHIFU) ablation for the treatment of uterine fibroids with T2 hyperintensity under MRI. A total of 131 uterine fibroids from 131 patients that appeared hyperintense under T2-weighted MRI were analyzed. The uterine fibroids were subjectively categorized into slight, irregular or regular enhancement groups, according to pretreatment dynamic contrast-enhanced MRI in the arterial phase within 60 sec after the injection of gadolinium. The non-perfused volume (NPV), which is indicative of successful ablation, was represented as the non-perfused area inside the uterine fibroids on enhanced MRI scans following treatment. Additionally, the treatment duration, treatment efficiency, sonication duration, energy efficiency ratio and any adverse events were recorded. The results indicated that the average NPV ratio for all the treated fibroids was 68.5%, while the average NPV ratios for fibroids with slight, irregular or regular enhancement were 84.7, 70.6 and 57.1%, respectively. Fibroids with regular enhancement were associated with the lowest NPV ratio and the lowest treatment efficiency, but exhibited the highest energy effect ratio and an elevated risk of severe adverse effects. The results of the present study indicate that hyperintense uterine fibroids with slight and irregular enhancement in the arterial phase of dynamic contrast-enhanced MRI are suitable for USgHIFU treatment. By contrast, uterine fibroids with regular enhancement were associated with the lowest treatment efficacy and safety.

Volumetric MR-guided high-intensity focused ultrasound with direct skin cooling for the treatment of symptomatic uterine fibroids: proof of concept study

Objective. To prospectively assess the safety and technical feasibility of volumetric magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) ablation with direct skin cooling (DISC) during treatment of uterine fibroids. Methods. In this proof-of-concept study, eight patients were consecutively selected for clinical MR-HIFU ablation of uterine fibroids with the use of an additional DISC device to maintain a constant temperature () at the interface between the HIFU table top and the skin. Technical feasibility was verified by successful completion of MR-HIFU ablation. Contrast-enhanced T1-weighted MRI was used to measure the treatment effect (nonperfused volume (NPV) ratio). Safety was evaluated by recording of adverse events (AEs) within 30 days’ follow-up. Results. All MR-HIFU treatments were successfully completed in an outpatient setting. The median NPV ratio was 0.56 (IQR [0.27–0.72]). Immediately after treatment, two patients experienced coldness related discomfort which resolved at the same day. No serious (device-related) AEs were reported. Specifically, no skin burns, cold injuries, or subcutaneous edema were observed. Conclusion. This study showed that it is safe and technically feasible to complete a volumetric MR-HIFU ablation with DISC. This technique may reduce the risk of thermal injury to the abdominal wall during MR-HIFU ablation of uterine fibroids. This trial is registered with NTR4189.

High intensity focused ultrasound ablation for submucosal fibroids: A comparison between type I and type II

Objective: The aim of this study was to compare high-intensity focused ultrasound (HIFU) treatment for type I and type II submucosal fibroids. Materials and methods: From October 2011 to October 2013, 55 patients with submucosal fibroids were enrolled in this study. Based on submucosal fibroid classification, 27 patients were grouped as type I submucosal fibroids, and 28 patients were classified as type II submucosal fibroids. All patients received HIFU treatment and completed 1-, 6-, and 12-month follow-ups. Adverse effects were recorded. Results: There were no significant differences in the baseline characteristics between the two groups (p > 0.05). Using similar sonication power, sonication time, and acoustic energy, the non-perfused volume (NPV) ratio was 83.0 ± 17.3% in the type I group, and 92.0 ± 9.5% in the type II group. All the patients tolerated the procedure well, and no serious adverse events occurred. During the follow-up intervals, the treated fibroids shrank and fibroid-related symptoms were relieved. No other reinterventional procedures were performed during the follow-up period. Conclusion: Based on our results with a small number of subjects, HIFU is suitable for both type I and type II submucosal fibroids. It seems that type II submucosal fibroids are more sensitive to HIFU ablation. Future studies with larger sample sizes and longer follow-up times to investigate the long-term results, including long-term symptom relief, pregnancy outcomes, and the recurrence rate as well as the reintervention rate are needed.

Scaled signal intensity of uterine fibroids based on T2-weighted MR images: a potential objective method to determine the suitability for magnetic resonance-guided focused ultrasound surgery of uterine fibroids.

Magnetic Resonance-guided Focused Ultrasound Surgery (MRgFUS) is a non-invasive method to treat uterine fibroids. To help determine the patient suitability for MRgFUS, we propose a new objective measure: the scaled signal intensity (SSI) of uterine fibroids in T2 weighted MR images (T2WI). Forty three uterine fibroids in 40 premenopausal women were included in this retrospective study. SSI of each fibroid was measured from the screening T2WI by standardizing its mean signal intensity to a 0-100 scale, using reference intensities of rectus abdominis muscle (0) and subcutaneous fat (100). Correlation between the SSI and the non-perfused volume (NPV) ratio (a measure for treatment success) was calculated. Pre-treatment SSI showed a significant inverse-correlation with post treatment NPV ratio (p < 0.05). When dichotomizing NPV ratio at 45 %, the optimal cut off value of the SSI was found to be 16.0. A fibroid with SSI value 16.0 or less can be expected to have optimal responses. The SSI of uterine fibroids in T2WI can be suggested as an objective parameter to help in patient selection for MRgFUS. • Signal intensity of fibroid in MR images predicts treatment response to MRgFUS. • Signal intensity is standardized into scaled form using adjacent tissues as references. • Fibroids with SSI less than 16.0 are expected to have optimal responses.

Intraprocedure contrast enhanced ultrasound: The value in assessing the effect of ultrasound-guided high intensity focused ultrasound ablation for uterine fibroids

PurposeTo investigate the value of microbubble contrast-enhanced ultrasound (CEUS) in evaluating the treatment response of uterine fibroids to HIFU ablation. Materials and methodsSixty-eight patients with a solitary uterine fibroid from the First Affiliated Hospital of Chongqing Medical University were included and analyzed. All patients underwent pre- and post-treatment magnetic resonance imaging (MRI) with a standardized protocol, as well as pre-evaluation, intraprocedure, and immediate post-treatment CEUS. CEUS and MRI were compared by different radiologists. ResultsIn comparison with MRI, CEUS showed that the size of fibroids, volume of fibroids, size of non-perfused regions, non-perfused volume (NPV) or fractional ablation (NPV ratio) was similar to that of MRI. In terms of CEUS examination results, the median volume of fibroids was 75.2 (interquartile range, 34.2–127.3) cm3, the median non-perfused volume was 54.9 (interquartile range, 28.0–98.1) cm3, the mean fractional ablation was 83.7±13.6 (range, 30.0–100.0)%. In terms of MRI examination results, the median volume of fibroids was 74.1 (interquartile range, 33.4–116.2) cm3. On the basis of contrast-enhanced T1-weighted images immediately after HIFU treatment, the median non-perfused volume was 58.5 (interquartile range, 27.7–100.0) cm3, the average fractional ablation was 84.2±14.2 (range, 40.0–100.0)%. ConclusionsCEUS clearly showed the size of fibroids and the non-perfused areas of the fibroid. Results from CEUS correlated well with results obtained from MRI.

Volumetric MR-Guided High-Intensity Focused Ultrasound with Direct Skin Cooling for the Treatment of Symptomatic Uterine Fibroids: Proof-of-Concept Study

Objective. To prospectively assess the safety and technical feasibility of volumetric magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) ablation with direct skin cooling (DISC) during treatment of uterine fibroids. Methods. In this proof-of-concept study, eight patients were consecutively selected for clinical MR-HIFU ablation of uterine fibroids with the use of an additional DISC device to maintain a constant temperature (T ≈ 20°C) at the interface between the HIFU table top and the skin. Technical feasibility was verified by successful completion of MR-HIFU ablation. Contrast-enhanced T1-weighted MRI was used to measure the treatment effect (nonperfused volume (NPV) ratio). Safety was evaluated by recording of adverse events (AEs) within 30 days' follow-up. Results. All MR-HIFU treatments were successfully completed in an outpatient setting. The median NPV ratio was 0.56 (IQR [0.27–0.72]). Immediately after treatment, two patients experienced coldness related discomfort which resolved at the same day. No serious (device-related) AEs were reported. Specifically, no skin burns, cold injuries, or subcutaneous edema were observed. Conclusion. This study showed that it is safe and technically feasible to complete a volumetric MR-HIFU ablation with DISC. This technique may reduce the risk of thermal injury to the abdominal wall during MR-HIFU ablation of uterine fibroids. This trial is registered with NTR4189.

MRI predictors of clinical success in MR-guided focused ultrasound (MRgFUS) treatments of uterine fibroids: results from a single centre.

To assess the technical and clinical results of MRgFUS treatment and factors affecting clinical treatment success. A total of 252 women (mean age, 42.1 ± 6.9 years) with uterine fibroids underwent MRgFUS. All patients underwent MRI before treatment. Results were evaluated with respect to post-treatment nonperfused volume (NPV), symptom severity score (SSS), reintervention rate, pregnancy and safety data. NPV ratio was significantly higher in fibroids characterized by low signal intensity in contrast-enhanced T1-weighted fat saturated MR images and in fibroids distant from the spine (>3 cm). NPV ratio was lower in fibroids with septations, with subserosal component and in skin-distant fibroids (p < 0.001). NPV ratio was highly correlated with clinical success: NPV of more than 80 % resulted in clinical success in more than 80 % of patients. Reintervention rate was 12.7 % (mean follow-up time, 19.4 ± 8 months; range, 3-38). Expulsion of fibroids (21 %) was significantly correlated with a high clinical success rate. No severe adverse events were reported. Adequate patient selection and correct treatment techniques, based on the learning curve of this technology, combined with technical advances of the system, lead to higher clinical success rates with low complications rate, comparable to other uterine-sparing treatment options. • MRgFUS appears to be a valid alternative to other uterus-preserving therapies • Patient selection is a significant factor in achieving high NPV ratios • MRI screening parameters correlate with the amount of fibroid ablation in MRgFUS • NPV results of more than 80 % correlate with higher clinical success rates.