Contrast-enhanced ultrasound for evaluation of high-intensity focused ultrasound treatment of benign uterine diseases: retrospective analysis of contrast safety

Complications and adverse events of high-intensity focused ultrasound in its application to gynecological field - a systematic review and meta-analysis

OBJECTIVE

To analyze and summarize the types, incidence rates and relevant influencing factors of adverse events (AEs) after high-intensity focused ultrasound ablation of gynecological diseases and provide reference and basis for handling such events in clinical practice.

METHOD

We searched PubMed, Cochrane Library, Web of Science and Embase databases to retrieve all literature since its establishment until February 2024. We evaluated the quality of included literature and publication bias and conducted a meta-analysis of single group rates for various AEs using Stata 17.0.

RESULTS

This systematic review finally included 41 articles. We summarized 34 kinds of AEs in 7 aspects and conducted a single group rate meta-analysis and sub-group analysis of 16 kinds of AEs. Among the common AEs of High-Intensity Focused Ultrasound (HIFU), the incidence of lower abdominal pain/pelvic pain is 36.1% (95% CI: 24.3%∼48.8%), vaginal bleeding is 20.6% (95% CI: 13.9%∼28.0%), vaginal discharge is 14.0% (95% CI: 9.6%∼19.1%), myoma discharge is 24% (95% CI: 14.6%∼34.8%), buttock pain is 10.8% (95% CI: 6.0%∼16.5%) and sacral pain is 10% (95% CI: 8.8%∼11.2%). Serious complications include uterine rupture, necrotic tissue obstruction requiring surgical intervention, third degree skin burns and persistent lower limb pain or movement disorders.

CONCLUSION

The common AEs after HIFU surgery are mostly mild and controllable, and the incidence of serious complications is extremely low. By reasonable prevention and active intervention, these events can be further reduced, making it a safe and effective treatment method. It is a good choice for patients who crave noninvasive treatment or have other surgical contraindications.

Combination of HIFU with sulfur hexafluoride microbubbles in the treatment of solitary uterine fibroids: a systematic review and meta-analysis

OBJECTIVES

To assess the efficacy and safety of sulfur hexafluoride microbubbles on ultrasound-guided high-intensity focused ultrasound (HIFU) ablation of uterine fibroids.

METHODS

Studies that compared HIFU-microbubble combination with HIFU-only in patients with uterine fibroids were searched from inception to April 2022. The standardized mean difference (SMD) or relative risk (RR) with 95% confidence interval (CI) for different outcome parameters was calculated.

RESULTS

Seven studies were included, with a total of 901 patients (519 in the combination group and 382 in the HIFU-only group). The energy consumption for treating 1 cm3 of the lesion in the combination group was less than that in the HIFU-only group [SMD =  - 2.19, 95%CI (- 3.81, - 0.57), p = 0.008]. The use of microbubbles was associated with shortening the duration of the treatment and sonication [SMD =  - 2.60, 95%CI (- 4.09, - 1.10), p = 0.0007; SMD =  - 2.11, 95%CI (- 3.30, - 0.92), p = 0.0005]. The rates of significant greyscale changes during HIFU were greater in the combination group, as well as the increase of non-perfused volume ratio [RR = 1.26, 95%CI (1.04, 1.54), p = 0.02; SMD = 0.32, 95%CI (0.03, 0.61), p = 0.03]. The average sonication durations to reach significant greyscale changes and for ablating 1 cm3 of the fibroid lesion were shorter in the combination group [SMD =  - 1.24, 95%CI (- 2.02, - 0.45), p = 0.002; SMD =  - 0.22, 95%CI (- 0.42, - 0.02), p = 0.03]. The two groups had similar post-HIFU adverse effects, while the combination group had fewer intraprocedural adverse events like abdominal pain, sacrum pain, and leg pain.

CONCLUSIONS

Sulfur hexafluoride microbubbles can be safely used to enhance and accelerate the ablation effects of HIFU in the treatment of uterine fibroids.

CLINICAL RELEVANCE STATEMENT

The combination of HIFU with sulfur hexafluoride microbubbles offers a promising non-invasive treatment option for patients with uterine fibroids.

KEY POINTS

• Sulfur hexafluoride microbubbles combined with ultrasound-guided high-intensity focused ultrasound (USgHIFU) has potential advantages in the treatment of uterine fibroids. • Sulfur hexafluoride microbubbles not only enhance the effects of USgHIFU treatment for uterine fibroids but also shorten its duration. • Sulfur hexafluoride microbubbles do not increase the incidence of USgHIFU-related adverse events in the treatment of uterine fibroids.

Role of ultrasonography in the evaluation of disease severity and treatment efficacy in adenomyosis

BACKGROUND

Adenomyosis is a benign disorder characterized by the presence of ectopic endometrial glands and stroma within the myometrium. The main clinical manifestations of adenomyosis are dysmenorrhea, menorrhagia, and infertility, which affect patients' quality of life. Recently, with advancements in imaging techniques, magnetic resonance imaging, and ultrasonography have become the main diagnostic tools for adenomyosis. In addition to the diagnosis and differential diagnosis of adenomyosis, ultrasonography can also be used to evaluate the severity of adenomyosis. The emergence of new techniques, such as elastography and contrast-enhanced ultrasonography (CEUS), has significantly improved the accuracy of ultrasound-based diagnosis of adenomyosis. These two imaging tools can also be used for the differential diagnosis of adenomyosis and the evaluation of treatment efficacy after medication or ablation procedure.

OBJECTIVE

we review the efficacy of ultrasonography as a diagnostic tool for adenomyosis. We also aim to introduce the potential of ultrasound imaging in the evaluation of the severity of this disease, as well as the application of elastography and contrast-enhanced ultrasonography (CEUS) in its diagnosis.

RESULTS AND CONCLUSION

Our findings reveal the potential value of ultrasonography combined with elastography and/or CEUS as medication guidance and efficacy evaluation tools in the long-term management of adenomyosis.

Sacral injury and influencing factors after ultrasonic ablation of uterine fibroids ≤30 mm from the sacrum

PURPOSE

To study sacral injuries and influencing factors after ultrasonic ablation of uterine fibroids no more than 30 mm from the sacrum.

METHODS

A total of 406 patients with uterine fibroids who underwent percutaneous ultrasound ablation were analyzed retrospectively. All patients underwent contrast-enhanced magnetic resonance imaging (MRI) scans before and after high-intensity focused ultrasound. The abnormal signal intensity (low signal intensity on T1WI and high signal intensity on T2WI) on the postoperative MRIs was indicative of a sacral injury. The patients were divided into a sacrum injury group and a sacrum non-injury group. The relationship between fibroid characteristics, ultrasound ablation parameters, and injury was analyzed using univariate and multivariate analyses.

RESULTS

There were 139 cases of sacral injury (34.24%). When the distance from the fibroid's dorsal side to the sacrum was 0-10 mm, the risk assessment showed that the danger of sacral injury increased by 1.85 times and 3.03 times compared with that at a distance of 11-20 or 21-30 mm. Furthermore, the risk of sacral injury increased by 1.89 times and 3.23 times when the therapeutic dose (TD) of a fibroid was >500 KJ compared with that of a fibroid with TD= 250-500 KJ and <250 KJ.

CONCLUSION

A distance of 10 mm or less and a TD of >500 KJ were significantly correlated with sacral injury. The distance from the fibroid's dorsal side to the sacrum and the TD were the main causes of injury to the sacrum. A distance of 10 mm or less and a TD of >500 KJ carried higher injury risks, while a distance of 21-30 mm and a TD of <250 KJ were the most appropriate circumstances to reduce the risk of sacral injury.

Application value of contrast-enhanced ultrasonography in the treatment of uterine fibroids by high-intensity focused ultrasound ablation: A retrospective study

PURPOSE

To determine efficacy and safety of contrast-enhanced ultrasonography (CEUS) in high-intensity focused ultrasound (HIFU) ablation of uterine fibroids (UFs).

METHODS

We retrospectively reviewed women undergoing HIFU ablation for UFs between June 2018 and January 2020. Before and after HIFU, patients underwent CEUS and magnetic resonance imaging (MRI) examinations. The relationship between CEUS features and ablation rate was analyzed. The time-intensity curves on CEUS were measured before and after HIFU ablation, and compared with those obtained using MRI. Adverse reactions were recorded.

RESULTS

A total of 64 patients were included. The immediate HIFU ablation rate significantly differed between low-, iso-, and high-enhancement UFs (87.2% ± 1.6%, 83.3% ± 2.1%, and 72.9% ± 3.1%, respectively; p < 0.05). On CEUS, the peak time of the time-intensity curve was significantly longer after treatment than before treatment (32.2 ± 9.7 and 26.7 ± 9.4 s, respectively; p < 0.05). Peak intensity was significantly lower after treatment than before treatment (13.7 ± 7.5 and 30.9 ± 11.2 dB, respectively; p < 0.05). All measurements were comparable between CEUS and MRI. The most common peri- and post-procedure adverse reaction was pain, which was temporary.

CONCLUSION

CEUS could dynamically and safely evaluate the immediate effects of the HIFU ablation of UFs.

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.

Contrast-Enhanced Ultrasound Imaging of Uterine Disorders: A Systematic Review

Uterine disorders are often presented with overlapping symptoms. The microvasculature holds specific information important for diagnosing uterine disorders. Conventional sonography is an established diagnostic technique in gynecology, but is limited by its inability to image the microvasculature. Contrast-enhanced ultrasound (CEUS), is capable of imaging the microvasculature by means of intravascular contrast agents; that is, gas-filled microbubbles. We provide a literature overview on the use of CEUS in diagnosing myometrial and endometrial disorders, that is, fibroids, adenomyosis, leiomyosarcomas and endometrial carcinomas, as well as for monitoring and enhancing the effectiveness of minimally invasive therapies. A systematic literature search with quality assessment was performed until December 2020. In total 34 studies were included, published between 2007 and 2020.The results entail a description of contrast-enhancement patterns obtained from healthy tissue and from malignant and benign tissue; providing a first base for potential diagnostic differentiation in gynecology. In addition it is also possible to determine the degree of myometrial invasion in case of endometrial carcinoma using CEUS. The effectiveness of minimally invasive therapies for uterine disorders can safely and accurately be assessed with CEUS. In conclusion, the abovementioned applications of CEUS are promising and it is worth further exploring its full potential for gynecology by designing innovative and methodologically high-quality clinical studies.

Image-guided thermal ablation in the management of symptomatic adenomyosis: a systematic review and meta-analysis

OBJECTIVE

To evaluate the clinical effects of image-guided thermal ablation for the treatment of symptomatic adenomyosis (AD).

DATA SOURCES

We searched PubMed, Web of Science, Cochrane Library, EMBASE, ClinicalTrials.gov and Google Scholar for literature from January 2000 to September 2020.

METHODS OF STUDY SELECTION

We included all studies reporting clinical outcomes of image-guided thermal ablation for AD, involving high-intensity focused ultrasound (HIFU), percutaneous microwave ablation (PMWA) and radiofrequency ablation (RFA). Two independent researchers performed study selection according to the screening criteria.

RESULTS

A total of 38 studies representing 15,908 women were included. Compared with those at baseline, the visual analog scale scores, the symptom severity scores and the menorrhagia severity scores decreased significantly after these thermal ablation therapies. The mean ablation time was 92.18 min, 24.15 min and 31.93 min during HIFU, PMWA and RFA, respectively. The non-perfused volume ratio of AD was 68.3% for HIFU, 82.5% for PMWA and 79.2% for RFA. The reduction rates of uterine volume were 33.6% (HIFU), 46.8% (PMWA) and 44.0% (RFA). The reduction rates of AD volume were 45.1% (HIFU), 74.9% (PMWA) and 61.3% (RFA). The relief rates of dysmenorrhea were 84.2% (HIFU), 89.7% (PMWA) and 89.2% (RFA). The incidence of minor adverse events was 39.0% (HIFU), 51.3% (PMWA) and 3.6% (RFA). The re-intervention rates were 4.0% (HIFU) and 28.7% (RFA). The recurrence rate was 10.2% after HIFU. The pregnancy rates were 16.7% (HIFU), 4.93% (PMWA) and 35.8% (RFA).

CONCLUSION

Image-guided HIFU, PMWA and RFA may be effective and safe minimally invasive therapies for symptomatic AD.

The safety of echo contrast-enhanced ultrasound in high-intensity focused ultrasound ablation for abdominal wall endometriosis: a retrospective study

Background

We aimed to investigate the efficacy and safety of echo contrast-enhanced ultrasound (CEUS) during high-intensity focused ultrasound (HIFU) ablation therapy for abdominal wall endometriosis (AWE).

Methods

A total of 67 patients with AWE were treated with HIFU ablation, and their demographic characteristics were retrospectively analysed. Blood perfusion of the focal lesion was assessed before the operation, during ablation and after the operation with the use of an ultrasound contrast agent, and the effect of the ultrasound contrast agent on treatment was assessed over a 1-year follow-up period. The degree of symptom relief and adverse effects were evaluated after HIFU ablation.

Results

Eighty-two lesions were ablated in 67 patients. CEUS showed that all lesions were successfully ablated with HIFU. The shrinkage ratio of the lesions significantly increased over the follow-up period. Intermittent pain disappeared at 1 month after the operation, and the patients' pain scores significantly decreased at the 1-year follow-up. The mean [± standard deviation (SD)] lesion volume was 7.64±8.95 cm³ on B-mode ultrasound. The post-HIFU non-perfused volume was 18.34±24.08 cm³, and the rate of massive changes on greyscale imaging was 96.16%±5.44% at 12 months. During the procedure, the main complications were a prickling sensation and tenderness in the treatment area and/or a transient "hot" sensation on the skin. After the procedure, there was no obvious discomfort except for pain. Two patients developed an approximately 1-cm area of skin that exhibited a waxy appearance. Seven patients had haematuria. No severe complications were observed.

Conclusions

Ultrasound contrast agents are effective and safe for evaluating the effect of HIFU ablation on AWE, and this approach provides significant guidance and evaluation benefits for the use of HIFU treatment for AWE without obvious side effects.

Contrast-Enhanced Ultrasound for Monitoring Non-surgical Treatments of Uterine Fibroids: A Systematic Review

Non-surgical treatment options for uterine fibroids are uterine artery embolization (UAE), high-intensity focused ultrasound ablation (HIFUA), and percutaneous microwave ablation (PMWA). Magnetic resonance imaging (MRI) is the reference standard imaging method before and after these procedures. Contrast-enhanced ultrasound (CEUS) has been studied as an alternative to MRI for evaluating the fibroids' characteristics and responses to non-surgical treatments. PubMed, Ovid MEDLINE and Scopus databases were searched for literature published from January 2000 through June 7, 2020, that investigated the application of CEUS as an adjunct to monitor UAE, HIFUA or PMWA in human uterine fibroid treatments. Two independent reviewers analyzed 128 publications, out of which 17 were included. Based on this systematic review, CEUS provides detailed data about fibroid volume and vascularization prior, during and post UAE, and it helps determine the endpoint of the procedure. HIFUA with intra-procedural CEUS has faster volume shrinkage over a shorter time period with less needed energy and provides early detection of residual tissue after HIFUA. CEUS and contrast-enhanced MRI have sufficient agreement to be used interchangeably in the clinic to evaluate the therapeutic effect of PMWA and HIFUA on fibroids.

High-intensity focused ultrasound and laparoscopic myomectomy in the treatment of uterine fibroids: a comparative study

OBJECTIVE

To compare the clinical efficacies of high-intensity focused ultrasound (HIFU) and laparoscopic myomectomy (LM) in the treatment of uterine fibroids and their effects on patients' quality of life.

DESIGN

A non-randomised control study.

SETTING

Gynaecological department in a university teaching hospital.

POPULATION

Patients with uterine fibroids.

METHODS

From November 2014 to November 2015, 166 patients with uterine fibroids were enrolled and underwent HIFU (n = 99) and LM (n = 67) surgeries, respectively. Clinical efficacy, postoperative complications and quality of life after treatment were evaluated using the SF-36 Scale to compare the differences in each variable at the 1-year follow up.

MAIN OUTCOMES MEASURES

Differences in efficacy, safety and quality of life between the patients treated with HIFU and LM.

RESULTS

The 12-month follow-up results showed that the HIFU group had a total effective rate of 99%; only one patient underwent alternative treatment due to non-apparent tumour shrinkage. All patients in the LM group showed complete tumour disappearance. Of these patients, 52 showed significant clinical improvement, 15 with partial clinical improvement, a total effective rate of 98%. There was no significant difference in effectivity rate between the two groups (P > 0.05). Both treatments effectively improved patients' quality of life. Compared with the LM group, patients in the HIFU group experienced no blood loss, a shorter hospital stay and fewer adverse effects and complications, the difference being statistically significant (P < 0.05).

CONCLUSIONS

High-intensity focused ultrasound can be as efficacious as LM therapy and effectively improve patients' quality of life in the treatment of uterine fibroids, with fewer adverse effects and complications, shorter hospital stays, and quicker postoperative recovery compared with LM therapy.

TWEETABLE ABSTRACT

Patients with uterine fibroids can be effectively treated with both HIFU and myomectomy.

Clinical Usefulness of the Microbubble Contrast Agent SonoVue in Enhancing the Effects of High-Intensity Focused Ultrasound for the Treatment of Adenomyosis

OBJECTIVE

To evaluate the clinical usefulness of the microbubble contrast agent SonoVue in enhancing high-intensity focused ultrasound (HIFU) for the treatment of adenomyosis.

METHODS

A total of 102 patients with adenomyosis, assessed from August 2015 to April 2017, were randomly divided into 1-minute (A) and 10-minute (B) groups, respectively. In groups A and B, HIFU started 1 minute and 10 minutes, respectively, after SonoVue injection. All patients underwent a magnetic resonance imaging scan before and after HIFU treatment.

RESULTS

The occurrence rates of massive gray scale change, nonperfused volume, and fractional ablation were similar in both groups (P > .05). Meanwhile, sonication time to massive gray scale change was reduced in group A compared with group B (P < .05). In addition, mean power, total energy, and energy efficiency factor were lower in group A than group B (all P < .05). The incidence rates of most perioperative and all postoperative adverse events were similar in both groups (P > .05). The incidence rates of pain in the treated region, leg pain, and sciatic or buttock pain during HIFU were substantially lower in group A than group B (P < .05).

CONCLUSIONS

Overall, starting HIFU sonication at 1 minute after SonoVue injection enhances HIFU ablation by cavitation and heating and is safe. Early massive gray scale change, lower total energy, and reduced mean power are potential safety factors.

A comparison of the cost-utility of ultrasound-guided high-intensity focused ultrasound and hysterectomy for adenomyosis: a retrospective study

OBJECTIVE

To evaluate cost-effectiveness of ultrasound-guided high-intensity focused ultrasound (USgHIFU) and open hysterectomy for adenomyosis.

DESIGN

A retrospective analysis.

SETTING

Gynaecological department in a single centre in China.

POPULATION

Patients with symptomatic adenomyosis.

MAIN OUTCOME MEASURES

Cost difference between patients with adenomyosis treated with USgHIFU and open hysterectomy.

METHODS

Three hundred and sixty-eight patients with adenomyosis were retrospectively reviewed. Among them, 302 patients were treated with USgHIFU and 66 patients with open hysterectomy. All of them had 1-, 3-, 6- and 12-month follow ups. The patients' quality of life (QOL) was evaluated and the utility scores were obtained from a rating scale to conduct a cost-utility analysis (CUA).

RESULTS

No significant differences were found at any follow-up time point in the QOL between the two groups (P > 0.05). After treatment, the QOL scores significantly increased in both groups (P < 0.05): the quality adjusted life year (QALY) for patients treated with USgHIFU was USUS$5256.48, whereas it was USUS$7510.03 for patients treated with open hysterectomy. Both incremental cost and sensitivity analysis showed that USgHIFU was less costly than open hysterectomy.

CONCLUSIONS

The QOL of patients with adenomyosis can be significantly improved by either USgHIFU or open hysterectomy, but USgHIFU is less costly.

TWEETABLE ABSTRACT

USgHIFU can safely be used to treat patients with adenomyosis and significantly improved the quality of life of patients after treatment. The cost of USgHIFU is less than that of surgical treatment.

Comparison of Contrast Enhanced Ultrasound With Contrast Enhanced Computed Tomography for the Diagnosis of Hepatocellular Carcinoma

BACKGROUND/AIMS

The most common primary malignant tumor of liver is hepatocellular carcinoma (HCC). The highest risk of developing HCC is seen in patients of cirrhosis. Ultrasound is used for surveillance in these patients. This study evaluates the role of contrast enhanced ultrasound (CEUS) in the diagnosis of HCC and compares CEUS to contrast enhanced computed tomography (CECT).

MATERIALS AND METHODS

This prospective study included 22 patients with cirrhosis and suspected to have HCC on the basis of gray scale ultrasound or elevated Alpha-fetoprotein. Multiphasic CECT and CEUS were done. On both CECT and CEUS, arterial phase enhancement patterns of the lesions were classified as heterogeneously hyperenhancing, homogeneously hyperenhancing, isoenhancing or nonenhancing. The enhancement patterns of the lesions in portal venous phase were classified as hyperenhancing, isoenhancing, washout or nonenhancing. Presence or absence of neovascularity and peripheral capsule were also noted. The diagnosis of HCC was made as per American Association for the Study of Liver Diseases (AASLD) guidelines.

RESULTS

There was moderate degree of agreement between the two modalities in characterizing the enhancement pattern in arterial phase, as calculated by using kappa test (k = 0.59, P < 0.05). Substantial agreement between them, for demonstrating the neovascularity, was also seen (k = 0.772, P < 0.05). CEUS was found to be superior to CECT in demonstrating portal venous phase wash out and peripheral capsule. Only fair agreement was seen between them, with kappa value for portal venous washout being k = 0.38 (P < 0.05) and for peripheral capsule being k = 0.328 (P < 0.05).

CONCLUSION

CEUS is comparable to CECT in demonstrating the arterial phase enhancement pattern of HCC and the neovascularity. CEUS was found to be better than CECT in demonstrating the portal venous phase washout and peripheral capsule.

In Vitro and In Vivo Investigation of High-Intensity Focused Ultrasound (HIFU) Hat-Type Ablation Mode

Background

The aim of this study was to investigate the feasibility of the application of high-intensity focused ultrasound (HIFU) hat-type ablation mode in in vitro and in vivo models, and to compare the ablation effects of different parameter combinations.

Material/Methods

HIFU hat-type ablation was performed in isolated bovine liver tissue and in the liver tissue in living rabbits, and the coagulative necrosis for different parameter combinations (plane angles and irradiation order) was investigated. We also analyzed and compared the ablation effects of traditional ablation and hat-type ablation modes. Coagulative necrosis morphology was detected with TTC staining, and the coagulative necrosis volume and energy efficiency factor (EEF) were calculated and compared.

Results

Coagulative necrosis was observed in all the ablated groups, and the coagulative necrosis volume was much larger than the irradiation area. The coagulative necrosis induced by the hat-type ablation was more regular and controllable than the traditional ablation. The angles between the ablation planes determined the coagulative necrosis morphology, but did not affect the coagulative necrosis volume. Moreover, the irradiation order significantly influenced the coagulative necrosis. Importantly, under certain conditions, hat-type ablation achieved higher efficiency compared with the traditional ablation mode.

Conclusions

Compared with the traditional ablation mode, HIFU hat-type ablation effectively shortened the irradiation time, reduced the over-accumulation of energy, and increased the HIFU ablation efficiency.

Contrast-enhanced ultrasound evaluation of pancreatic cancer xenografts in nude mice after irradiation with sub-threshold focused ultrasound for tumor ablation

We evaluated the efficacy of contrast-enhanced ultrasound for assessing tumors after irradiation with sub-threshold focused ultrasound (FUS) ablation in pancreatic cancer xenografts in nude mice. Thirty tumor-bearing nude mice were divided into three groups: Group A received sham irradiation, Group B received a moderate-acoustic energy dose (sub-threshold), and Group C received a high-acoustic energy dose. In Group B, B-mode ultrasound (US), color Doppler US, and dynamic contrast-enhanced ultrasound (DCE-US) studies were conducted before and after irradiation. After irradiation, tumor growth was inhibited in Group B, and the tumors shrank in Group C. In Group A, the tumor sizes were unchanged. In Group B, contrast-enhanced ultrasound (CEUS) images showed a rapid rush of contrast agent into and out of tumors before irradiation. After irradiation, CEUS revealed contrast agent perfusion only at the tumor periphery and irregular, un-perfused volumes of contrast agent within the tumors. DCE-US perfusion parameters, including peak intensity (PI) and area under the curve (AUC), had decreased 24 hours after irradiation. PI and AUC were increased 48 hours and 2weeks after irradiation. Time to peak (TP) and sharpness were increased 24 hours after irradiation. TP decreased at 48 hours and 2 weeks after irradiation. CEUS is thus an effective method for early evaluation after irradiation with sub-threshold FUS.

Contrast-enhanced ultrasonography of cervical carcinoma: perfusion pattern and relationship with tumour angiogenesis

OBJECTIVE

This study aimed to investigate the use of contrast-enhanced ultrasonography (CEUS) and time-intensity curves to assess angiogenesis in cervical cancer.

METHODS

60 patients who were scheduled to undergo radical surgery for biopsy-proven cervical cancers underwent CEUS. Surgical tissue sections from 32 patients who did not receive neoadjuvant chemotherapy were analyzed with CD34 staining to estimate intratumoral microvessel density (MVD). CEUS images were analyzed for maximum intensity (IMAX), rise time (RT), time to peak (TTP) and mean transit time.

RESULTS

Cervical lesions had a higher IMAX and shorter RT and TTP (p < 0.001) than reference regions. There was a linear association between the IMAX of the cervical lesion and the mean intratumoral MVD (r = 0.624, p < 0.001). There were no significant differences in CEUS variables according to histological type, grade and stage.

CONCLUSION

Quantitative CEUS variables have potential use for monitoring perfusion changes in tumours after non-surgical therapy for advanced cervical cancer.

ADVANCES IN KNOWLEDGE

The article demonstrates the capability and value of quantitative CEUS as a non-invasive strategy for detecting the perfusion and angiogenic status of cervical cancer. Quantitative CEUS variables have potential use for monitoring tumour response to non-surgical therapy.