title: Laser-induced interstitial thermotherapy via a single-needle delivery system: Optimal conditions of ablation, pathological and ultrasonic changes.
abstract: This study aimed to examine the optimal conditions of laser-induced interstitial thermotherapy (LITT) via a single-needle delivery system, and the ablation-related pathological and ultrasonic changes. Ultrasound (US)-guided LITT (EchoLaser system) was performed at the output power of 2-4 Wattage (W) for 1-10 min in ex vivo bovine liver. Based on the results of the ex vivo study, the output power of 3 and 4 W with different durations was applied to in vivo rabbit livers (n=24), and VX2 tumors implanted in the hind limbs of rabbits (n=24). The ablation area was histologically determined by hematoxylin-eosin (HE) staining. Traditional US and contrast enhanced ultrasound (CEUS) were used to evaluate the treatment outcomes. The results showed: (1) In the bovine liver, ablation disruption was grossly seen, including a strip-like ablation crater, a carbonization zone anteriorly along the fiber tip, and a surrounding gray-white coagulation zone. The coagulation area, 1.2 cm in length and 1.0 cm in width, was formed in the bovine liver subjected to the ablation at 3 W for 5 min and 4 W for 4 min, and it extended slightly with the ablation time. (2) In the rabbit liver, after LITT at 3 W for 3 min and more, the coagulation area with length greater than or equal to 1.2 cm, and width greater than or equal to 1.0 cm, was found. Similar coagulation area was seen in the implanted VX2 carcinoma at 3 W for 5 min. (3) Gross examination of the liver and carcinoma showed three distinct regions: ablation crater/carbonization, coagulation and congestion distributed from the center outwards. (4) Microscopy revealed four zones after LITT, including ablation crater/carbonization, coagulation, edema and congestion from the center outwards. A large area with coagulative necrosis was observed around a vessel in the peripheral area with edema and hyperemia. (5) The size of coagulation was consistent well to the CEUS findings. It was concluded that EchoLaser system at low power can produce a coagulation area larger than 1.0 cm×1.0 cm during a short time period. The real-time US imaging can be used to effectively guide and assess the treatment.
authors.affiliation: Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
authors.forename: Yan-Rong
authors.initials: YR
authors.lastname: Zhang
authors.affiliation: Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
authors.forename: Ling-Yun
authors.initials: LY
authors.lastname: Fang
authors.affiliation: Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Yu
authors.affiliation: Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
authors.forename: Zhen-Xing
authors.initials: ZX
authors.lastname: Sun
authors.affiliation: Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Pathology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Guo
authors.affiliation: Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
authors.forename: Fei-Xiang
authors.initials: FX
authors.lastname: Xiang
authors.affiliation: Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
authors.forename: Cheng-Fa
authors.initials: CF
authors.lastname: Lu
authors.affiliation: Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
authors.forename: Tian-Wei
authors.initials: TW
authors.lastname: Yan
authors.affiliation: Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Lv
authors.affiliation: Department of Ultrasound, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China. xiemx64@126.com.
authors.forename: Ming-Xing
authors.initials: MX
authors.lastname: Xie
mesh_terms: D000818:Animals; D001859:Bone Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000628:therapy*; D002417:Cattle; D006614:Hindlimb / Q000473:pathology; D053685:Laser Therapy / Q000295:instrumentation* / Q000379:methods; D008107:Liver Diseases / Q000000981:diagnostic imaging / Q000628:therapy*; D011817:Rabbits; D016896:Treatment Outcome; D014464:Ultrasonic Therapy / Q000295:instrumentation / Q000379:methods*; D014463:Ultrasonography