High-intensity focused ultrasound treatment of liver tumours: post-treatment MRI correlates well with intra-operative estimates of treatment volume

Abstract

Objectives: To assess the safety and feasibility of high-intensity focused ultrasound (HIFU) ablation of liver tumours and to determine whether post-operative MRI correlates with intra-operative imaging. Methods: 31 patients were recruited into two ethically approved clinical trials (median age 64; mean BMI 26 kg m 22). Patients with liver tumours (primary or metastatic) underwent a single HIFU treatment monitored using intra-operative Bmode ultrasound. Follow-up consisted of radiology and histology (surgical trial) or radiology alone (radiology trial). Radiological follow-up was digital subtraction contrast-enhanced MRI. Results: Treatment according to protocol was possible in 30 of 31 patients. One treatment was abandoned because of equipment failure. Transient pain and superficial skin burns were seen in 81% (25/31) and 39% (12/31) of patients, respectively. One moderate skin burn occurred. One patient died prior to radiological follow-up. Radiological evidence of ablation was seen in 93% (27/29) of patients. Ablation accuracy was good in 89% (24/27) of patients. In three patients the zone of ablation lay #2 mm outside the tumour. The median cross-sectional area (CSA) of the zone of ablation was 5.0 and 5.1 cm 2 using intra-operative and post-operative imaging, respectively. The mean MRI:B-mode CSA ratio was 1.57 [95% confidence interval (CI)50.57-2.71]. There was positive correlation between MRI and B-mode CSA (Spearman's r50.48; 95% CI 0.11-0.73; p50.011) and the slope of linear regression was significantly non-zero (1.23; 95% CI50.68-1.77; p,0.0001). Conclusions: HIFU ablation of liver tumours is safe and feasible. HIFU treatment is accurate, and intra-operative assessment of treatment provides an accurate measure of the zone of ablation and correlates well with MRI follow-up. Colorectal cancer is one of the leading causes of mortality in Europe and the USA [1]. Of those diagnosed with colorectal cancer, 20-30% will have metastases in the liver at the time of diagnosis, and overall 50% will develop liver metastases during the course of their disease [2,3]. Despite this, at post-mortem, approximately one-quarter of patients are found to have metastases confined to the liver, and so the possibility of cure in such patients is available if these metastases can be treated effectively. Hepatic resection is feasible in only 10-25%, and although it is associated with an operative mortality of up to 5%, it can achieve 5-year survival rates in the region of 40% [4]. The favoured current alternative to surgery is combination chemotherapy, but this is associated with an objective response rate of just 20-50%, and relatively short median overall survival of approximately 12 months [5]. As a result there have been considerable efforts to provide minimally invasive alternatives to surgery for these patients. These alternatives include transarterial chemo-embolisation (TACE), direct percutaneous ethanol injection (PEI), and energy-based ablative techniques such as radiofrequency ablation (RFA), cryoablation, microwave th...

High intensity focused ultrasound (HIFU) applied to hepato-bilio-pancreatic and the digestive system—current state of the art and future perspectives

“…Forty-four studies reported on the clinical use of HIFU (7,(10)(11)(12)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33) to treat liver lesions , while 19 series were found on HIFU treatment for pancreatic cancers (6,(56)(57)(58)(59)(60)(61)(62)(63)(64)(65)(66)(67)(68)(69)(70)(71)(72)(73) and 4 studies included patients suffering from both liver and pancreatic cancers (74)(75)(76)(77), reporting on a total of 1,682 and 823 cases for the liver and pancreas, respectively. However, the real number of patients who benefited from HIFU treatment is much larger, since a recent review article from Zhou reported on over 3,000 cases of advanced pancreatic cancer treated with HIFU alone or in combination with chemotherapy (CHT) or radiotherapy (RT) (78).…”

“…The most frequent complications were skin burns at the application sites and osteonecrosis of ribs or vertebra along the US pathway ( Tables 5,6). Post-HIFU pain was not assessed systematically and was reported in 17 studies (384 patients undergoing liver HIFU procedures) (7,12,(19)(20)(21)(22)24,26,28,29,32,39,41,45,49,54,75) and 6 studies (62 patients receiving HIFU for pancreatic malignancies) (56,59,62,70,71,75). In only a few of those trials, a semi-quantitative evaluation tool was used to report pain level, based on the analgesic requirements (mild = no analgesic; moderate = non-steroidal anti-inflammatory drugs; severe = required morphine) (7,19,20,24,39).…”

“…Image-guidance is crucial to plan the treatment strategy and also to follow-up the results of HIFU treatment (10)(11)(12) and the different devices used, including US and/or MRIguidance.…”

Ultrasound-guided tissue fractionation by high intensity focused ultrasound in an in vivo porcine liver model

“…HIFU is most widely used to thermally ablate a variety of both benign and malignant tumors including uterine fibroids, prostate cancer, liver tumors, and other solid tumors that are accessible to ultrasound energy (3)(4)(5)(6). It has been shown that HIFU therapy improves survival rates in certain oncological applications and improves outcomes in the treatment of benign conditions (1,5).…”

“…The results of a recent clinical trial of transcranial HIFU for the successful treatment of essential tremor in 15 patients is an incredible milestone demonstrating the potential of this technology (7). HIFU targeting is usually performed by using either magnetic resonance (MR) imaging or B-mode ultrasound imaging (3,8). Neither method allows for direct visualization of the treated volume; however, MR thermometry is capable of providing tissue temperature maps during treatment, which can be correlated to the thermal dose and permits the ablated tissue volume to be calculated.…”