An MR-HIFU mild hyperthermia heating algorithm was developed, resulting in accurate and homogeneous heating within the targeted region in vitro and in vivo, which is suitable for applications in drug delivery.

In this article, we discuss techniques that contribute to widening patient selection for MRI-guided HIFU therapy of uterine fibroids.

BackgroundUterine fibroids are the most common benign tumor in women, and surgical intervention is still the main fibroid treatment. Patient demands have encouraged development of less-invasive methods such as high-intensity focused ultrasound (HIFU). This study aimed to evaluate the safety and effectiveness of magnetic resonance-guided high-intensity focused ultrasound therapy using a volumetric ablation technique in the treatment of symptomatic uterine fibroids in China.MethodsOne hundred and seven patients were enrolled and treated with magnetic resonance-guided high-intensity focused ultrasound in this study. Clinical efficacy was based on the proportion of patients with fibroid shrinkage (10 % volume reduction or more compared to baseline) at 6 months post treatment as measured with magnetic resonance imaging. The quality of life and symptom outcome was assessed using the uterine fibroid symptom and quality of life questionnaire with symptom severity scoring. Safety was primarily assessed by evaluating the reported adverse events.ResultsNinety nine of the 107 treated patients had fibroid shrinkage at 6 months post treatment. Resulting in an overall 93 % (95 % confidence interval 86–97 %) treatment success rate, p value <0.001; the symptom severity scoring and health-related quality of life at 6 months was statistically different from the screening symptom severity scoring at 0.05 level. Of 366 adverse events reported, there were no study procedure-related or device-related serious adverse events were in the study.ConclusionsThis study demonstrated that the volumetric magnetic resonance-guided high-intensity focused ultrasound device is safe and technically effective and can be utilized in clinically efficient treatments of symptomatic uterine fibroids.Trial registration NCT01588899

In chest and sinus examinations, the amount of data was extensive, allowing national pediatric diagnostic reference levels to be defined. Parameter selection in pediatric examination protocols should be harmonized in order to reduce patient doses and improve optimization.

Background Up to half of all men who undergo primary radiotherapy for localized prostate cancer (PCa) experience local recurrence. Objective To evaluate the safety and early functional and oncological outcomes of salvage magnetic resonance imaging–guided transurethral ultrasound ablation (sTULSA) for men with localized radiorecurrent PCa. Design, setting, and participants This prospective, single-center phase 1 study ( NCT03350529 ) enrolled men with biopsy-proven localized PCa recurrence after radiotherapy. Multiparametric magnetic resonance imaging (mpMRI) and 18 F prostate-specific membrane antigen-1007 ( 18 F PSMA-1007) positron emission tomography (PET)-computed tomography (CT) were used to confirm organ-confined disease localization. Patients underwent either whole-gland or partial sTULSA, depending on their individual tumor characteristics. Outcome measurements and statistical analysis Patients were followed at 3-mo intervals. Adverse events (AEs, Clavien-Dindo scale), functional status questionnaires (Expanded Prostate Cancer Index [EPIC]-26, International Prostate Symptom Score, International Index of Erectile Function-5), uroflowmetry, and prostate-specific antigen (PSA) were assessed at every visit. Disease control was assessed at 1 yr using mpMRI and 18 F-PSMA-1007 PET-CT, followed by prostate biopsies. Results and limitations Eleven patients (median age 69 yr, interquartile range [IQR] 68–74) underwent sTULSA (3 whole-gland, 8 partial sTULSA) and have completed 12-mo follow-up. Median PSA was 7.6 ng/ml (IQR 4.9–10) and the median time from initial PCa diagnosis to sTULSA was 11 yr (IQR 9.5–13). One grade 3 and three grade 2 AEs were reported, related to urinary retention and infection. Patients reported a modest degradation in functional status, most significantly a 20% decline in the EPIC-26 irritative/obstructive domain at 12 mo. A decline in maximum flow rate (24%) was also observed. At 1 yr, 10/11 patients were free of any PCa in the targeted ablation zone, with two out-of-field recurrences. Limitations include the nonrandomized design, limited sample size, and short-term oncological outcomes. Conclusions sTULSA appears to be safe and feasible for ablation of radiorecurrent PCa, offering encouraging preliminary oncological control. Patient summary We present safety and 1-yr functional and oncological outcomes of magnetic resonance imaging–guided transurethral ultrasound ablation (TULSA) as a salvage treatment for local prostate cancer recurrence after primary radiation. Salvage TULSA is safe and shows the ability to effectively ablate prostate cancer recurrence, with acceptable toxicity.

BackgroundMagnetic resonance guided high-intensity focused ultrasound (MR-HIFU) therapy is not feasible in all patients with uterine fibroids because of limiting anatomical factors such as scar tissue, bowel loops or other obstacles in the sonication path. These may prevent the treatment or limit the treatment window, and therefore, also the volume where HIFU therapy can be delivered. Bowel loops present a particular problem because of bowel gas bubbles and hard particles which may cause reflection or absorption of ultrasound energy, potentially leading to thermal damage and even bowel perforation. Most commonly used techniques for bowel repositioning are bladder and/or rectum filling but these are not always sufficient to reposition the bowel loops. With more efficient bowel repositioning technique, the number of eligible patients for MR-HIFU treatment could be increased, and therapy efficacy be improved in cases where bowel loops limit the treatment window.Case presentationA wedged exterior gel pad was used in two patients presented with in total of four symptomatic fibroids undergoing MR-HIFU treatment when bladder and/or rectum filling was not sufficient to reposition the bowel loops. No severe adverse effects were observed in these cases. The non-perfused volume ratios (NPVs) immediately after treatment were 86% and 39% for the first patient, and 3% for the second patient.ConclusionsOur preliminary experience suggests that the use of a wedged gel pad during MR-HIFU treatment could be an effective tool to manipulate the bowels in cases where the bladder and/or rectum filling is not sufficient to reposition the bowel loops. A wedged gel pad could also be used in other situations to achieve better treatment coverage to the uterine fibroid.

A clinical case study of high-intensity focused ultrasound (HIFU) treatment in the uterine fibroid was conducted. During the therapy, poor heating efficacy was observed which could be attributed to several factors such as the local perfusion rate, patient-specific anatomy or changes in acoustic parameters of the ultrasound field. In order to determine the cause of the diminished heating, perfusion analyses and ultrasound simulations were conducted using the magnetic resonance imaging (MRI) data from the treatment. The perfusion analysis showed high local perfusion rate in the myoma (301.0 ± 25.6 mL/100 g/min) compared to the surrounding myometrium (233.8 ± 16.2 mL/100 g/min). The ultrasound simulations did not show large differences in the focal point shape or the acoustic pressure (2.07 ± 0.06 MPa) when tilting the transducer. However, a small shift (−2.2 ± 1.3 mm) in the axial location of the focal point was observed. The main causes for the dimin- * Corresponding ished heating were likely the high local perfusion and ultrasound attenuation due to the deep location of the myoma. c 2019 IEEE.

To investigate the safety and feasibility of magnetic resonance imaging (MRI)-guided transurethral ultrasound ablation (TULSA) for the treatment of benign prostatic obstruction (BPO). Patients and methodsAn investigator-initiated, prospective, registered (NCT03350529), phase I study enrolled men with lower urinary tract symptoms due to benign prostatic hyperplasia in need of surgical intervention. Patients were followed for 12 months after TULSA. Uroflowmetry, prostate-specific antigen (PSA) level, and a comprehensive set of functional questionnaires including the Expanded Prostate cancer Index Composite-26, International Prostate Symptom Score (IPSS) and five-item version of the International Index of Erectile Function were obtained at baseline and every 3 months afterwards. MRI was obtained at baseline, and at 3 and 12 months after TULSA. Medication use before and after TULSA were recorded. Adverse events (AEs) were reported using the Clavien-Dindo classification. ResultsA total of 10 men underwent TULSA with no severe AEs encountered. The baseline median (interquartile range [IQR]) age and prostate volume were 68 (63-72) years and 53 (45-66) mL, respectively. At baseline, six patients were moderately symptomatic and four patients severely symptomatic. Nine patients at baseline were on BPO medication. The median (IQR) improvement in the IPSS was 82%, from 17.5 (15.3-23.0) at baseline to 4.0 (2.3-6.3) at 12 months. Similarly, the median maximum urinary flow rate improved by 101%, from a median (IQR) of 12.4 (8.8-17.6) mL/s at baseline to 21.8 (17.6-26.5) mL/s at 12 months. Improvements were already seen at 3 months. The median prostate volume and PSA reduction at 12 months were 33% and 48%, respectively. There were no changes in continence, sexual, erectile or bowel functions. At 12 months, five out of six men with normal ejaculatory function before TULSA reported normal antegrade ejaculations. All patients taking BPO medication before TULSA discontinued medication after TULSA. ConclusionTULSA appears to be a safe and effective treatment for BPO, with promising 12-month follow-up outcomes. Further studies with larger cohorts are needed to confirm the observed results.