Oxytocin selectively reduces blood flow in uterine fibroids without an effect on myometrial blood flow: a dynamic contrast enhanced MRI evaluation

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.

Increased MR-guided high intensity focused ultrasound (MR-HIFU) sonication efficiency of uterine fibroids after carbetocin administration

Purpose

Method

Results

Conclusion

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Carbetocin administration resulted in more efficient MR-HIFU fibroid sonications.

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16.7% of the women experienced mild side effects of carbetocin administration.

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Carbetocin may lead to a broader patient eligibility and reduced treatment times.

Microbubble contrast agent SonoVue combined with oxytocin improves the efficiency of high-intensity focused ultrasound ablation for adenomyosis

BACKGROUND

To investigate the combined enhancing effects of microbubble-contrast SonoVue and oxytocin on high-intensity focused ultrasound (HIFU) ablation of adenomyosis.

METHODS

330 patients with adenomyosis were randomly assigned to SonoVue and oxytocin group (group A, n = 82), oxytocin (group B, n = 85), SonoVue (group C, n = 81), or the control (group D, n = 82) for HIFU ablation. In group A, oxytocin was dripped 0.32 IU/min, and HIFU ablation was started one minute after SonoVue injection. In group B, oxytocin was dripped 0.32 IU/min during ablation. In group C, HIFU ablation was started one minute after SonoVue injection. In group D, neither oxytocin nor SonoVue was applied. The clinical data, treatment results, and complications were analyzed.

RESULTS

All participants underwent HIFU treatment safely, and the mean energy efficiency factor (EEF) in the four groups was 4.7 ± 0.9J/mm³, 8.5 ± 0.6J/mm³, 8.9 ± 0.7J/mm³, and 12.6 ± 1.8J/mm³, respectively, with the mean ablation time (AT) of 633.7 ± 55.1 s, 874.2 ± 65.6 s, 936.3 ± 85.2 s, and 1103.2 ± 96.2 s, respectively. The non-perfused volume ratios (NPVR) were 90.4 ± 8.8%, 88.7 ± 9.1%, 89.4 ± 7.2%, 80.5 ± 7.9%, respectively. In addition, EEF and AT were the shortest in group A (p < 0.05). NPVR was significantly higher in group A than in the control group D (p < 0.05). The incidence rates of adverse events were not significantly different in the four groups (p > 0.05).

CONCLUSIONS

Compared to the control group, oxytocin combined with SonoVue in HIFU for adenomyosis can significantly decrease the energy and time needed for the ablation and safely enhance the treatment efficiency by improving the cavitation and heating of HIFU ablation and increasing the non-perfused volume ratio.

Feasibility of T2 relaxation time in predicting the technical outcome of MR-guided high-intensity focused ultrasound treatment of uterine fibroids

PURPOSE

The aim of this study was to assess the feasibility of T2 relaxation time in predicting the immediate technical outcome i.e., nonperfused volume ratio (NPVr) of magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU) treatment of symptomatic uterine fibroids and to compare it with existing T2-weighted imaging methods (Funaki classification and scaled signal intensity, SSI).

MATERIALS AND METHODS

30 patients with 32 uterine fibroids underwent an MRI study including a quantitative T2 relaxation time measurement prior to MRgHIFU treatment. T2 relaxation times were measured with a multi-echo fast imaging-based technique with 16 echoes. The correlation between pretreatment values of the uterine fibroids and treatment outcomes, that is nonperfused volume ratios (NPVr), was assessed with nonparametric statistical measures. T2 relaxation time-based method was compared to existing T2-weighted imaging-based methods using receiver-operating-characteristics (ROC) curve analysis and Chi-square test.

RESULTS

Nonparametric measures of association revealed a statistically significant negative correlation between T2 relaxation time values and NPVr. The T2 relaxation time classification (T2 I, T2 II, and T2 III) resulted in the whole model p-value of 0.0019, whereas the Funaki classification resulted in a p-value of 0.56. The T2 relaxation time classification (T2 I and T2 II) achieved a whole model of a p-value of 0.0024, whereas the SSI classification had a p-value of 0.0749.

CONCLUSIONS

A longer T2 relaxation time of the fibroid prior to treatment correlated with a lower NPVr. Based on our results, the T2 relaxation time classifications seem to outperform the Funaki classification and the SSI method.

Feasibility of apparent diffusion coefficient in predicting the technical outcome of MR-guided high-intensity focused ultrasound treatment of uterine fibroids - a comparison with the Funaki classification

PURPOSE

To investigate the feasibility of using an apparent diffusion coefficient (ADC) classification in predicting the technical outcome of magnetic resonance imaging-guided high-intensity focused ultrasound (MRgHIFU) treatment of symptomatic uterine fibroids and to compare it to the Funaki classification.

MATERIALS AND METHODS

Forty-two patients with forty-eight uterine fibroids underwent diffusion-weighted imaging (DWI) before MRgHIFU treatment. The DW images were acquired with five different b-values. Correlations between ADC values and treatment parameters were assessed. Optimal ADC cutoff values were determined to predict technical outcomes, that is, nonperfused volume ratios (NPVr) such that three classification groups were created (NPVr of <30%, 30-80%, or >80%). Results were compared to the Funaki classification using receiver-operating-characteristic (ROC) curve analysis, with statistical significance being tested with the Chi-square test.

RESULTS

A statistically significant negative correlation (Spearman's ρ = -0.31, p-value < 0.05) was detected between ADC values and NPV ratios. ROC curve analysis indicated that optimal ADC cutoff values of 980 × 10^-6mm²/s (NPVr > 80%) and 1800 × 10^-6mm²/s (NPVr < 30%) made it possible to classify fibroids into three groups: ADC I (NPVr > 80%), ADC II (NPVr 30-80%) and ADC III (NPVr < 30%). Analysis of the whole model area under the curve resulted in values of 0.79 for the ADC classification (p-value = 0.0007) and 0.62 for the Funaki classification (p-value = 0.0527).

CONCLUSIONS

Lower ADC values prior to treatment correlate with higher NPV ratios. The ADC classification seems to be able to predict the NPV ratio and may even outperform the Funaki classification. Based on these results DWI and ADC maps should be included in the MRI screening protocol.

Magnetic Resonance-Guided High-Intensity Focused Ultrasound Ablation of Uterine Fibroids-Efficiency Assessment with the Use of Dynamic Contrast-Enhanced Magnetic Resonance Imaging and the Potential Role of the Administration of Uterotonic Drugs

OBJECTIVE

The assessment of the usefulness of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) when qualifying patients with uterine fibroids (UFs) for magnetic resonance-guided high-intensity ultrasound (MR-HIFU).

MATERIAL AND METHODS

This retrospective, single center study included 283 women who underwent DCE-MRI and were treated with MR-HIFU. The patients were divided according to non-perfused volume (NPV) as well as by the type of curve for patients with a washout curve in the DCE-MRI study and patients without a washout curve. The studied women were assessed in three groups according to the type of uterotonics administered. Group A (57 patients) received one dose of misoprostol/diclofenac transvaginally and group B (71 patients) received oxytocin intravenously prior to the MR-HIFU procedure. The remaining 155 women (group C) were treated with the traditional non-drug enhanced MR-HIFU procedure.

RESULTS

The average NPV value was higher in no washout group, and depended on the uterotonics used.

CONCLUSIONS

We demonstrated a correlation between dynamic contrast enhancement curve types and the therapeutic efficacy of MR-HIFU. Our results suggest that DCE-MRI has the potential to assess treatment outcomes among patients with UFs, and patients with UFs that present with a washout curve may benefit from the use of uterotonic drugs. More studies are required to draw final conclusions.