Hepatic and Renal Histotripsy in an Anticoagulated Porcine Model.

PURPOSE: To determine the risk of mechanical vessel wall damage resulting in hemorrhage during and after hepatic and renal histotripsy in an anticoagulated in vivo porcine model. MATERIALS AND METHODS: Non-tumor-bearing pigs (n = 8; mean weight, 52.5 kg) were anticoagulated with warfarin (initial dose, 0.08 mg/kg) to a target prothrombin time (PT) of 30%-50% above baseline. A total of 15 histotripsy procedures were performed (kidney: n = 8, 2.0-cm sphere; liver: n = 7, 2.5-cm sphere). Treatments were immediately followed by computed tomography (CT) imaging. Animals were observed for 7 days while continuing anticoagulation, followed by repeat CT and necropsy. RESULTS: All animals survived to complete the entire protocol with no signs of disability or distress. Three animals had hematuria (pink urine without clots). Baseline PT values (mean, 16.0 seconds) were elevated to 22.0 seconds (37.5% above baseline, P = .003) on the day of treatment and to 28.8 seconds (77.8% above baseline, P < .001) on the day of necropsy. At the time of treatment, 5 of 8 (63%) animals were at a therapeutic anticoagulation level, and all 8 animals (100%) reached therapeutic levels by the time of necropsy. There were no cases of intraparenchymal, peritoneal, or retroperitoneal hemorrhage associated with any treatments despite 5 of 7 (71%) liver and all 8 (100%) kidney treatments extending to the organ surface. CONCLUSIONS: Liver and kidney histotripsy seems safe with no elevated bleeding risk in this anticoagulated animal model, supporting the possibility of histotripsy treatments in patients on anticoagulation.

Percutaneous Lung Biopsy with Pleural and Parenchymal Blood Patching: Results and Complications from 1,112 Core Biopsies.

PURPOSE: To evaluate the outcomes of computed tomography (CT) fluoroscopy-guided core lung biopsies with emphasis on diagnostic yield, complications, and efficacy of parenchymal and pleural blood patching to avoid chest tube placement. METHODS: This is a single-center retrospective analysis of CT fluoroscopy-guided percutaneous core lung biopsies between 2006 and 2020. Parenchymal blood patching during introducer needle withdrawal was performed in 74% of cases as a preventive measure, and pleural blood patching was the primary salvage maneuver for symptomatic or growing pneumothorax in 60 of 83 (72.2%) applicable cases. RESULTS: A total of 1,029 patients underwent 1,112 biopsies (532 men; mean age, 66 years; 38.6%, history of emphysema; lesion size, 16.7 mm). The diagnostic yield was 93.6% (1,032/1,103). Fewer complications requiring intervention were observed in patients who underwent parenchymal blood patching (5.7% vs 14.2%, P < .001). Further intervention was required in 83 of 182 pneumothorax cases, which included the following: (a) pleural blood patch (5.4%, 60/1,112), (b) chest tube placement without a pleural blood patch attempt (1.5%, 17/1,112), and (c) simple aspiration (0.5%, 6/1,112). Pleural blood patch as monotherapy was successful in 83.3% (50/60) of cases without need for further intervention. The overall chest tube rate was 2.6% (29/1,112). Emphysema was the only significant risk factor for complications requiring intervention (P ≤ .001). CONCLUSIONS: Parenchymal blood patching during introducer needle withdrawal decreased complications requiring intervention. Salvage pleural blood patching reduced the frequency of chest tube placement for pneumothorax.

Noninvasive thyroid histotripsy treatment: proof of concept study in a porcine model.

INTRODUCTION: This study was performed to determine the feasibility and safety of creating superficial histotripsy treatment in a live porcine thyroid model. METHODS: The porcine thymus comparable in size, shape and location to the human thyroid was used for this study. This model has been used for thyroid surgery studies due to the diminutive size of the porcine thyroid. Four female swine underwent a total of eight histotripsy treatments performed with a prototype therapy system (HistoSonics, Inc., Ann Arbor, MI). Two treatments were performed in each animal: a spherical 1.0 × 1.0 × 1.0 cm and ovoid 1.0 × 1.0 × 2.0 cm treatment zones. MRI immediately post-procedure was evaluated for histotripsy treatment zone size and imaging appearance, followed immediately by sacrifice. Tissue was then reviewed for percent cellular destruction and precision. RESULTS: Treatment zones measured on post treatment MRI were similar to prescribed volumes (spherical = 0.60 (+/- 0.11) cm3, ovoid = 1.23 (+/- 0.40) cm3, p > 0.05 vs. prescribed). MRI demonstrated well demarcated treatment zones and imaging findings consistent with cellular destruction. Histology demonstrated sharp transitions to normal tissue (mean 0.33 (+/- 0.13) cm), and high degrees of cellular destruction (mean 76% (+/- 12.5), range of 50-100%) in the treated tissue. Edema within the overlying muscle was seen in 2/8 treatments. CONCLUSION: Histotripsy is capable of safely creating precise histotripsy treatments within the superficial neck of a porcine thyroid model without evidence of considerable complications.