Learning Curve of USgHIFU Ablation for Uterine Fibroids: A Multi‐Center Prospective Study

Abstract

Objectives To verify the stability of high‐intensity focused ultrasound (HIFU) technology and the feasibility of training programs with learning curve cumulative summation (LC‐CUSUM). Methods A total of 12 physicians and 720 cases were equally assigned to the learning group and the control group, with 6 physicians and 360 cases per group. The learning group was treated by physicians without HIFU experience and the control group was treated by experienced physicians. Nonperfused volume (NPV) ratio was assessed by contrast‐enhanced magnetic resonance imaging. Technical failure was defined as NPV ratio of uterine fibroids <70% and/or major complication, while <80% was set as a stricter standard of training qualification. LC‐CUSUM was used to analyze the learning curve. Results Physicians with or without HIFU experience in both groups achieved matchable NPV ratios, where a NPV ratio of 92.52% (16.06) was achieved by experienced physicians and 93.82% (16.95) by inexperienced physicians. No major complication was observed. The results of LC‐CUSUM analysis showed that, with the standards of the NPV ratio of 70% or 80%, the learning group mastered the technique on the 11th case and the 16th case, respectively, while the control group was stable. Conclusions HIFU technology stayed stable in operation, with good safety and sound effectiveness, and was easy to learn. NPV ratio of 70% was considered as an appropriate indicator of training qualification. HIFU has remarkable prospects in achieving a NPV ratio of ≥80% without safety being compromised.

Achieving NPVR ≥ 80% as Technical Success of High-Intensity Focused Ultrasound Ablation for Uterine Fibroids: a cohort study

“…The long-term outcome of USgHIFU is comparable to that of myomectomy. Liu et al (21) showed that an NPVR of 70%…”

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

“…Interestingly, the long-term re-intervention rate was similar between the group with NPVR of 80–89% and the group with NPVR ≥ 90%, and the difference was not statistically significant ( P = 0.880). Liu et al [ 25 ] showed that an NPVR of 70% was considered an appropriate indicator of training quality. Gong et al [ 26 ] showed that experienced doctors can achieve 80% NPVR when treating uterine fibroids, and even more than 90% of doctors have more clinical experience.…”

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

“…Third, we did not try to use other NPVR values as prediction dividing lines for treatment success, only NPVR ≥ 80% was used in this study. Because measures to achieve 80% NPVR is technically feasible and have been proven to be highly associated with a clinical treatment success [ 3 , 4 , 38 ]. Finally, while patients at both institutions were treated with the same HIFU system, a potential biased limitation is that the treatment was performed by different doctors, which could influenced dosage delivery or the termination of treatment.…”

“…As an ablation technique, the efficacy of HIFU is closely related to the immediate postoperative non-perfused volume ratio (NPVR). A higher NPVR heralds a significant improvement in the patient’s symptoms, and an NPVR of over 80% is considered as an indicator of therapeutic success in recent studies [ 3 , 4 ]. However, not all patients can benefit from this treatment because of several limitations, such as high cellularity and high vascularity in the fibroids, which will hinder the deposition of ultrasonic energy and make ablation outcomes unsatisfactory.…”

“…In addition, some other factors, such as the location and diameter of the fibroids, will also affect the results of the ablation. Therefore, traditional classification based solely on T2MRI signal intensity may not be able to accurately predict treatment outcome [ 4 , 9 ].…”