Ultrasound-guided percutaneous laser ablation is safe and effective in the treatment of small renal tumors in patients at increased bleeding risk

Non-Fourier Bioheat Transfer Analysis in Brain Tissue During Interstitial Laser Ablation: Analysis of Multiple Influential Factors

This work presents the dual-phase lag-based non-Fourier bioheat transfer model of brain tissue subjected to interstitial laser ablation. The finite element method has been utilized to predict the brain tissue's temperature distributions and ablation volumes. A sensitivity analysis has been conducted to quantify the effect of variations in the input laser power, treatment time, laser fiber diameter, laser wavelength, and non-Fourier phase lags. Notably, in this work, the temperature-dependent thermal properties of brain tissue have been considered. The developed model has been validated by comparing the temperature obtained from the numerical and ex vivo brain tissue during interstitial laser ablation. The ex vivo brain model has been further extended to in vivo settings by incorporating the blood perfusion effects. The results of the systematic analysis highlight the importance of considering temperature-dependent thermal properties of the brain tissue, non-Fourier behavior, and microvascular perfusion effects in the computational models for accurate predictions of the treatment outcomes during interstitial laser ablation, thereby minimizing the damage to surrounding healthy tissue. The developed model and parametric analysis reported in this study would assist in a more accurate and precise prediction of the temperature distribution, thus allowing to optimize the thermal dosage during laser therapy in the brain.

Laser-Induced Blood Coagulation for Surgical Application: A Scoping Review

There is a lack of evidence-based reviews on the effects of laser irradiation on blood coagulation in the literature, despite a large number of clinical trials. We therefore evaluated the available evidence on laser irradiation parameters used in coagulation of blood to optimize physical parameters. We performed a literature search for recent scientific studies indexed between 2017 and 2023 using the databases of PubMed and ScienceDirect. Articles were selected based on defined inclusion and exclusion criteria, and 78 publications in total were eventually included in this scoping review. The following were found to produce significant benefits in blood coagulation for surgical application: (1) dentistry and oral surgeries: 980 nm, 27 s, 2 W, 1502.7 W/cm2, 26.5 J, 622 J/cm2, 400 μm; (2) urogenital disorders: 532 nm, 4 s, 40 W, 10600 W/cm2, 1.3 J, 424 J/cm2, 600 μm; (3) ophthalmic disorders: 810 nm, 1 s, 1 W, 3540 W/cm2, 0.75 J, 1326 J/cm2, 100 μm; (4) embryological surgeries: 1064 nm, 10 s, 25 W, 35400 W/cm2, 262.5 J, 371000 J/cm2, 332.5 μm; (5) dermatological disorders: 1064 nm, 20 W, 2440 W/cm2, 0.1 J, 24 J/cm2, 670 μm; (6) gastrointestinal disorders: 532 nm, 3 s, 20 W, 1051 W/cm2, 120 J, 26500 J/cm2, 760 μm; (7) neurological surgeries: 2.5 s, 1.5 W, 1035 W/cm2, 2 J, 1584 J/cm2, 385 μm; (8) pulmonary disorders: 1320 nm, 5s, 35 W, 12450 W/cm2, 250 J, 65000 J/cm2, 700 μm (9) cardiovascular disorders: 1064 nm, 16.5 s, 5 W, 1980.5 W/cm2, 900 J, 760 J/cm2, 400 μm. In conclusion, our scoping review identifies that combining data from all clinically heterogeneous studies suggests that laser irradiation reflects an effective method for inducing blood coagulation in several medical fields.

Management conundrum in a case of renal cell cancer (RCC) on dual antiplatelet therapy (DAPT) for recently placed coronary drug-eluting stent (DES)

A man in his 50s presented in an emergency with breathlessness and chest discomfort. On evaluation, he was diagnosed with coronary artery disease, with more than 80% narrowing of the right coronary and left circumflex arteries. The patient underwent percutaneous coronary intervention and was started on dual antiplatelet (DAPT) therapy. After starting DAPT, the patient developed gross haematuria with a drop in haematocrit. Further evaluation revealed a left renal mass with urinary bladder clots. Because of the risk of stent thrombosis on stopping DAPT, radical nephrectomy was deferred, and the patient underwent left renal artery angioembolisation and bladder clot evacuation. On the follow-up, the patient was stable with a gradual decrease in renal mass size, and after a year, the patient underwent definitive surgery. The patient is doing well in 4 years of follow-up with no metastasis.

Efficacy and safety of thermal ablation modalities for the treatment of papillary thyroid microcarcinoma: Systematic Review and network meta-analysis

Background

Thermal ablation (TA) modalities such as radiofrequency ablation (RFA), microwave ablation (MWA), and laser ablation (LA) have been widely used in the treatment of papillary thyroid microcarcinoma (PTMC) patients. Based on previous small-sample meta-analyses, this network meta was designed to further compare the efficacy and safety of these thermal ablation methods in PTMC patients.

Methods

China National Knowledge Infrastructure (CNKI), Wanfang, PubMed, Embase, and the Cochrane Library databases were searched to retrieve relevant studies published before May 2022. The efficacy outcomes was recurrence and lymph node metastasis (LNM), the safety outcome included operation time, intra-operative blood loss, hospital stays and complications. The Newcastle-Ottawa Scale (NOS) was selected for the risk of bias assessment. Stata 14.0 was used for statistical analysis.

Results

Twenty-nine articles were included. Based on as least 6 months follow up, our analysis discovered no significant statistical differences in all efficacy and safety outcomes between MWA, RFA, and LA groups. Moreover, three TA treatments all produced significant least operation time, hospital stays, and complications than surgery group. Additionally, our study found that RFA showed relatively less complications, LNM, operation time and intra-operative blood loss, compared with other TA treatments. MWA indicated the lowest probability of recurrence, LA showed the longest hospital stays.

Conclusions

MWA, RFA, and LA are all effective treatment strategies for patients with PTMC, but could not completely replace conventional surgical treatment.

Miniaturised dual-modality all-optical ultrasound probe for laser interstitial thermal therapy (LITT) monitoring

All-optical ultrasound (OpUS) has emerged as an imaging paradigm well-suited to minimally invasive imaging due to its ability to provide high resolution imaging from miniaturised fibre optic devices. Here, we report a fibre optic device capable of concurrent laser interstitial thermal therapy (LITT) and real-time in situ all-optical ultrasound imaging for lesion monitoring. The device comprised three optical fibres: one each for ultrasound transmission, reception and thermal therapy light delivery. This device had a total lateral dimension of <1 mm and was integrated into a medical needle. Simultaneous LITT and monitoring were performed on ex vivo lamb kidney with lesion depth tracked using M-mode OpUS imaging. Using one set of laser energy parameters for LITT (5 W, 60 s), the lesion depth varied from 3.3 mm to 8.3 mm. In all cases, the full lesion depth could be visualised and measured with the OpUS images and there was a good statistical agreement with stereomicroscope images acquired after ablation (t=1.36, p=0.18). This work demonstrates the feasibility and potential of OpUS to guide LITT in tumour resection.

Laser technology in urologic oncology

Laser technology has been used in Urology since the 80s with a lot of different applications in endoscopic and open surgery. With the developments of the technology and the introduction of new active medium and source of laser energy, this technology have become the gold standard not only in stone surgery but even in benign prostate enlargement (BPE) surgical treatment. Regarding urologic oncology, laser energy has now reached an important role in focal therapy and in conservative treatment. The possibility of having better functional outcomes without any relevant impact on oncological results led to an increased use of laser in penile surgery, with a significant mention in urological guidelines for this option. In urothelial cancers as well, both in conservative management of upper tract tumors that in the treatment of non muscle invasive bladder cancer, a clear role of these relatively new source of energy have been demonstrated. Finally, both in prostate that in renal cancer the strategy of focal therapy may take advantage from this precise and fine technology. In this review we analyzed and described the applications of laser energy in urological cancers with a specific focus on penile, urothelial and prostate cancer.

A cohort study of microwave ablation and surgery for low-risk papillary thyroid microcarcinoma

BACKGROUND

The optimal treatment method for papillary thyroid microcarcinoma (PTMC) is lacking consensus. Here we aimed to compare the efficacy and safety of surgery and microwave ablation (MWA) for PTMC.

METHODS

The clinical data of 644 patients with PTMC treated between July 2013 and June 2020 were retrospectively analyzed. A total of 320 and 324 patients underwent MWA and surgery, respectively. We observed lesion changes in the MWA group and compared the recurrence, metastasis, complications, and other health economic indicators between the 2 groups.

RESULTS

The mean follow-up time was 890.7 ± 532.9 (187.9-2679.0) days in the MWA group and 910.9 ± 568.4 (193.8-2821.5) days in the surgery group. In the MWA group, lesion volume increased significantly after ablation and then gradually decreased. The final lesion volume reduction rate was 90.73% ± 7.94%, and 193 lesions (60.3%) disappeared completely. There were no significant intergroup differences in recurrence or metastasis. The incidence of main complications (temporary hypothyroidism, hypoparathyroidism, and temporary hoarseness) was significantly lower in the MWA group than in the surgery group (p < 0.001). The treatment time, intraoperative blood loss, and hospital stay were significantly lower in the MWA group than in the surgery group (p < 0.001).

CONCLUSIONS

MWA is effective for treating PTMC, with a low incidence of complications and less trauma. The rates of post-treatment recurrence and metastasis are similar to those of surgery, indicating that MWA is a suitable alternative to surgery.

Real-Time US-CT fusion imaging for guidance of thermal ablation in of renal tumors invisible or poorly visible with US: results in 97 cases

PURPOSE

To assess the capability of ultrasound-computed tomography (US-CT) fusion imaging to guide a precise targeting of renal tumors invisible or poorly visible with US.

MATERIALS AND METHODS

From 2016 renal tumors poorly visible or inconspicuous/invisible at US were treated at our institution with the guidance of US/CT fusion in a room equipped with CT scanner. Feasibility of the procedure, accuracy of targeting, complications, and technique efficacy were evaluated.

RESULTS

Of 227 patients treated from 2016 to March 2020, 91 patients (65 males and 26 females, mean age 68.5 ± 10.1 years) with 97 renal lesions (mean maximum diameter 21.6 ± 9.4 mm) inconspicuous/invisible (29/97, 29.9%) or poorly visible (68/97, 70.1%) at US underwent treatment under US-CT fusion guidance. US-CT fusion imaging guidance was always technically feasible and enabled correct targeting in 97/97/(100%) of cases. Technical success was achieved in 93/97 lesions (95.9%). Three lesions were retreated during the same ablative session, while 1 was retreated in a subsequent session. Thus, primary efficacy was achieved in one session in 96/97 (98.9%) cases and secondary efficacy in 97/97 (100%) cases.

CONCLUSION

US-CT image fusion guidance allows for a correct tumor targeting of renal tumors poorly visible or inconspicuous/invisible with US alone, with a high rate of technical success and technique efficacy.

Real-time US/cone-beam CT fusion imaging for percutaneous ablation of small renal tumours: a technical note

INTRODUCTION

Fusion imaging is gaining attention as an imaging technique to assist minimally invasive tumour ablation. Ultrasound (US) and computed tomography (CT) are the most common imaging modalities to guide thermal ablation of renal tumours, yet cone-beam CT (CBCT) has recently been described to successfully assist percutaneous renal interventions. Our goal was to evaluate primary technical success and correct lesion targeting of US/CBCT fusion imaging to guide the ablation of kidney masses < 2 cm in a small group of patients.

MATERIAL AND METHODS

Six renal lesions (maximum diameter 11-17 mm) were treated with RFA in 5 different patients using real-time US/CBCT. Fusion imaging was used to identify and monitor tumour ablation. Demographics, tumour characteristics and mean serum creatinine levels were recorded before and after the procedure. Primary technical success and correct lesion targeting represented the main endpoints of the study. Primary technique efficacy was confirmed at 1-month and 3-month contrast-enhanced CT follow-ups.

RESULTS

In all cases, a confident US/CBCT synchronisation was reached and allowed for a correct targeting and a successful percutaneous ablation. Primary technique efficacy was 100%. No recurrence was observed at the follow-up that ranged from 8 to 26 months (mean 16 months).

CONCLUSIONS

US/CBCT fusion proved to be a viable method to precisely guide safe and effective percutaneous thermal ablation in patients with small renal tumours, especially when hardly detectable on US.

KEY POINTS

• US/CBCT fusion imaging for renal ablation is safe and feasible. • US/CBCT fusion imaging allows for an improved targeting and complete ablation of small RCC with poor US-conspicuity.

Thermal Ablation for Papillary Thyroid Microcarcinoma: How Far We Have Come?

Purpose

Thermal ablation (TA), as one of the most currently remarkable technologies, has achieved great success in many malignant diseases including but not limited to hepatic and renal carcinoma. In recent years, this technology was gradually introduced to the treatment of papillary thyroid microcarcinoma (PTMC) and even papillary thyroid carcinoma (PTC). Thereby, we summarized the current progress of TA development in the treatment of PTMC.

Methods

The latest relevant literature from the PubMed database with keywords "thermal ablation", "papillary thyroid microcarcinoma", "microwave ablation", "radio-frequency ablation", and "laser ablation", among others, were comprehensively reviewed in this article. The follow-up outcomes of patients in these articles were analyzed.

Results

The efficacy and safety of TA including microwave ablation (MWA), laser ablation (LA), and radiofrequency ablation (RFA) in the treatment of PTC and PTC have been intensively studied. Based on existing clinical trials, the relatively long-term follow-up (range, from 6 to 64.2 months) results in MWA, LA, and RFA were satisfactory that tumor volume reduction rate (VRR) reached and even surpass 99%. Compared with routine surgery methods (total thyroidectomy and lobectomy), the incidence rate of complications was relatively lower and the recurrence rate of TA techniques was not statistically significant, whereas the operative time, blood loss, length of hospital stay, and hospital cost were significantly decreased.

Conclusion

TA presents the same satisfactory therapeutic effects but minimal postoperative trauma can significantly improve the patients' quality of life. However, future larger sample, multicenter, and prospective randomized controlled trials are urgently needed to validate the feasibility of TA in dealing with PTMC.

Liver-directed therapies for liver metastases from neuroendocrine neoplasms: Can laser ablation play any role?

Aggressive cytoreduction can prolong survival in patients with unresectable liver metastases (LM) from neuroendocrine neoplasms (NEN), and minimally invasive, liver-directed therapies are gaining increasing interest. Catheter-based treatments are used in disseminated disease, whereas ablation techniques are usually indicated when the number of LM is limited. Although radiofrequency ablation (RFA) is by far the most used ablative technique, the goal of this opinion review is to explore the potential role of laser ablation (LA) in the treatment of LM from NEN. LA uses thinner needles than RFA, and this is an advantage when the tumors are in at-risk locations. Moreover, the multi-fiber technique enables the use of one to four laser fibers at once, and each fiber provides an almost spherical thermal lesion of 12-15 mm in diameter. Such a characteristic enables to tailor the size of each thermal lesion to the size of each tumor, sparing the liver parenchyma more than any other liver-directed therapy, and allowing for repeated treatments with low risk of liver failure. A recent retrospective study reporting the largest series of LM treated with LA documents both safety and effectiveness of LA, that can play a useful role in the multimodality approach to LM from NEN.

Image-guided thermal ablation of central renal tumors with retrograde cold pyeloperfusion technique: a monocentric experience

Purpose: To evaluate feasibility, safety and efficacy of image-guided thermal ablations associated with retrograde pyeloperfusion in patients with centrally located renal tumors.Materials and methods: 48 patients (15 women, 33 men, mean age 69.1 ± 11.8) were treated with image-guided thermal ablation associated with pyeloperfusion for 58 centrally located renal tumors (mean diameter 32.3 ± 7.32 mm). 7 patients had a single kidney. Microwave and radiofrequency ablation were used. All treatments were performed with ultrasound, CT, or fusion imaging guidance under general anesthesia and simultaneous retrograde cold pyeloperfusion technique.Results: Procedure was feasible in all cases. Technical success and primary technical efficacy were reached in 51/58 (88%) and 45/54 tumors (83%). With a second ablation performed in 5 tumors, secondary technical efficacy was achieved in 50/50 (100%) tumors. Minor and major complications occurred in 8/58 (13%) and 5/58 (8%) tumors. No significative change in renal function occurred after treatment.During follow-up, 5 recurrences occurred, that were retreated with a second ablation. At last follow up (mean 32.2 ± 22.0 months), 41/48 (85%) treated patients were free from disease. The median TTP and PFS were 27.0 (range, 2.3-80.0) and 26.5 months (range, 2.3-80.0), respectively.Conclusion: Image-guided thermal ablation associated with protective pyeloperfusion is a feasible, safe, and effective treatment option for patients with central renal tumors with a minimal impact on renal function and relevant potential to avoid nephrectomy.

Percutaneous ablation techniques for renal cell carcinoma: current status and future trends

Percutaneous ablation is an increasingly applied technique for the treatment of localized renal tumors, especially for elderly or co-morbid patients, where co-morbidities increase the risk of traditional nephrectomy. Ablative techniques are technically suited for the treatment of tumors generally not exceeding 4 cm, which has been set as general consensus cutoff and is described as the upper threshold of T1a kidney tumors. This threshold cutoff is being challenged, but with still limited evidence. Percutaneous ablation techniques for the treatment of renal cell carcinoma (RCC) include radiofrequency ablation, cryoablation, laser or microwave ablation; the main advantage of all these techniques over surgery is less invasiveness, lower complication rates and better patient tolerability. Currently, international guidelines recommend percutaneous ablation either as intervention for frail patients or as a first line tool, provided that the tumor can be radically ablated. The purpose of this article is to describe the basic concepts of percutaneous ablation in the treatment of RCC. Controversies concerning techniques and products and the need for patient-centered tailored approaches during selection among the different techniques available will be discussed.

Long-Term Follow-Up Outcomes after Percutaneous US/CT-Guided Radiofrequency Ablation for cT1a-b Renal Masses: Experience from Single High-Volume Referral Center

Image-guided thermal ablations are increasingly applied in the treatment of renal cancers, under the guidance of ultrasound (US) or computed tomography (CT). Sometimes, multiple ablations are needed. The aim of the present study was to evaluate the long-term results in patients with renal mass treated with radiofrequency ablation (RFA) with both US and CT, with a focus on the multiple ablations rate. 149 patients (median age 67 years) underwent RFA from January 2008 to June 2015. Median tumor diameter was 25 mm (IQR 17–32 mm). Median follow-up was 54 months (IQR 44–68). 27 (18.1%) patients received multiple successful ablations, due to incomplete ablation (10 patients), local tumor progression (8 patients), distant tumor progression (4 patients) or multiple tumor foci (5 patients), with a primary and secondary technical efficacy of 100%. Complications occurred in 13 (8.7%) patients (6 grade A, 5 grade C, 2 grade D). 24 patients died during follow-up, all for causes unrelated to renal cancer. In conclusion, thermal ablations with the guidance of US and CT are safe and effective in the treatment of renal tumors in the long-term period, with a low rate of patients requiring multiple treatments over the course of their disease.

Image-guided laser ablation in the treatment of recurrence of renal tumours: technique and preliminary results

Abdominal recurrences of renal cell carcinoma (RCC) after surgery might represent a challenge for treatment, often requiring difficult surgeries or anticipated systemic therapy. Our aim is to illustrate a novel application of laser ablation for the treatment of abdominal recurrences of RCC. Patients with abdominal recurrences of renal cancer were treated under ultrasound/computed tomography guidance with a diode laser inserted into the lesion through a thin 21-G needle. A fixed 3-W power protocol was used, changing the illumination time according to lesion dimension and shape. Also, technical success, technical efficacy, local tumour progression, and major and minor complications were retrospectively analysed. Three patients were treated with image-guided laser ablation for abdominal recurrences of RCC. In all cases, it was possible to perform ablation as preoperatively planned and all three nodules (size of 6, 8, and 12 mm) were completely ablated with no evidence of residual enhancement after 6 weeks at contrast-enhanced CT. No minor or major complications were observed. No local tumour progression was reported up to 12 months from ablation. Image-guided laser ablation holds the potential to offer a minimally invasive treatment to patients with abdominal recurrence of RCC. Further studies are needed to evaluate the clinical role of this technique.

The Efficacy and The Safety of Ultrasound-guided Ablation Therapy for Treating Papillary Thyroid Microcarcinoma

The prevalence of papillary thyroid microcarcinoma (PTMC) increases rapidly all around the world, but the management of PTMC hasn't reached a consensus. Recently, ultrasound-guided (US-guided) ablation therapy was introduced as a feasible treatment for low-risk PTMC. The clinical application of US-guided ablation therapy needs doctors' effort to investigate the efficacy and the safety of US-guided ablation in treating PTMC carefully. Although the present evidence showed some limitations, such as short-term study time spans and no randomized control design, in our perspective, US-guided thermal ablation therapy has good short-term efficacy and safety and is a promising PTMC's treatment in future clinical practice.

Laser thermal ablation to treat a recurrent soft-tissue sarcoma of the leg: a case report

We present the case of a 52-year-old male patient with recurrence of a soft-tissue sarcoma of the left leg treated with percutaneous laser ablation. The patient received the diagnosis of sarcoma for the first time in 2011; further local recurrences and a pulmonary metastatic spread occurred during follow-up, so the patient has been treated several times with chemotherapy, limb-sparing surgery and radiotherapy. In September 2017, a new local recurrence of sarcoma occurred, for which limb amputation was proposed but refused by the patient. Laser ablation with ultrasound guidance was performed, with complete ablation at 6 months and limb salvage.

Image-Guided Thyroid Ablation: Proposal for Standardization of Terminology and Reporting Criteria

Background: Image-guided tumor ablation is commonly performed in clinical practice. Trying to standardize terminology and data collection to enable a more reliable comparison among the different studies, in 2003, a document entitled "Image-Guided Tumor Ablation: Proposal for Standardization of Terms and Reporting Criteria" was published by the International Working Group on Image-Guided Tumor Ablation. Since then, ablations have evolved significantly, with the development of new technology and techniques and applications. This has included benign thyroid nodules, and their ablation has become increasingly accessible, not only among radiologists but also among other specialists involved in thyroid care, including endocrinologists and surgeons. This has resulted in further inhomogeneity in how data are presented and reported among different studies, resulting in a need for standardization to homogenize language and data reporting on the topic. Summary: In February 2018 in Milano, Italy, a meeting involving specialists concerned with minimally invasive treatments of thyroid lesions was organized, and the Italian Working Group on Minimally Invasive Treatments of the Thyroid was founded with the aim of establishing a collaborative network among all clinicians working in this field. The first work of this group is to present a proposal for standardization of terminology and reporting criteria on image-guided ablations to treat benign thyroid nodules. Conclusion: This proposal was drafted with the goal of providing guidance for standardized reporting of results in studies regarding image-guided thyroid ablations. We encourage adoption of this terminology worldwide, anticipating that this will facilitate improved communication and understanding within the field and stimulate further discussion on the topic over the next years.

Percutaneous laser ablation for benign and malignant thyroid diseases

Minimally invasive image-guided thermal ablation is becoming increasingly common as an alternative to surgery for the treatment of benign thyroid nodules. Among the various techniques for thermal ablation, laser ablation (LA) is the least invasive, using the smallest applicators available on the market and enabling extremely precise energy deposition. However, in some cases, multiple laser fibers must be used simultaneously for the treatment of large nodules. In this review, the LA technique is described, and its main clinical applications and results are discussed and illustrated.

Augmented reality for interventional oncology: proof-of-concept study of a novel high-end guidance system platform

Background

To assess the feasibility of a novel system that uses augmented reality to guide interventional oncology procedures.

Methods

This study was conducted in accordance to the guidelines of the local institutional review boards. Evaluation of an augmented reality system based upon a tablet, a needle handle and a set of markers was performed in three experimental models. Initially, a male anthropomorphic trunk phantom equipped with five polyvinyl chloride bars (two of 16 cm in length and 3 cm in diameter and four of 45, 30 or 20 cm in length and 2 cm in diameter) was used to study the accuracy of the system without respiratory motion or tissue compression. Next, small metallic targets were placed in a porcine model to evaluate how respiration affects the system accuracy. Finally, the performance of the system on a more complete model, a cadaver with liver metastasis, was tested.

Results

In all experimental settings, extremely high targeting accuracy of < 5 mm in all cases was achieved: 2.0 ± 1.5 mm (mean ± standard deviation) for the anthropomorphic model, 3.9 ± 0.4 mm for the porcine model, and 2.5 mm and 2.8 mm for the two metastases in the cadaver model.

Conclusions

Augmented reality can assist with needle guidance with great target accuracy for interventional procedures by simultaneously visualising three-dimensional reconstructed anatomical structures, tumour targets and interventional devices on a patient’s body, enabling performance of procedures in a simple and confident way.