Purpose: The hypothesis of this study was that histotripsy, an ultrasound therapy that disrupts tissue mechanically through the action of bubble clouds, increases the short-term rate of acute thrombus clearance for catheter-directed thrombolysis Materials and Methods: Thrombi formed in the femoral vein of pigs were treated with CDT, histotripsy, or CDT and histotripsy (histotripsy+). Ultrasound (B-mode and color Doppler) and contrast fluoroscopy imaging data were scored by 4 observers for semiquantitative evaluation of each arm with ordinal regression models. Further, B-mode images were manually annotated by 3 observers to quantify the thrombus clearance rate. Results: A total of 27 thrombi (2.0 cm [SD +/- 0.4] in length) in 27 animals were considered in this study (N = 8 for CDT, N = 9 for histotripsy, and N =10 for histotripsy+). The mean treatment duration was 20.2 minutes (SD +/- 1.3). The ordinal regression models indicated that the thrombus clearance rate increased for histotripsy+ relative to CDT based on B-mode and color Doppler but not fluoroscopy (P = .015, P = .001, and P = .900, respectively). Manual annotation of B-mode images denoted that histotripsy+ had an increased thrombus clearance rate relative to CDT and histotripsy (P = .001 and P = .022, respectively). Petechial hemorrhage was present in the perivascular soft tissue for 2 cases with histotripsy and 1 case with histotripsy+. Conclusions: The clearance of acute thrombus was similar for treatment with CDT or histotripsy. Combining these individual approaches further increased the rate of thrombus clearance based on multiple imaging metrics.

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Bronchial stenosis is a rare and potentially life-threatening condition in children that can be challenging to address.1 Bronchoscopic treatment of bronchial stenosis in adults is more well-established, however adapting endoscopic approaches to children can be limited by the smaller diameter of their airways, with limited reports on the use of fiberoptic bronchoscopic balloon dilation in children. In this report, we describe the case of a child with multifocal bronchial stenosis in the context of granulomatosis with polyangitis (GPA), who successfully underwent bronchial recanalization and balloon dilation using a novel fluoroscopic and bronchoscopic approach. A 12-year-old male with a diagnosis of GPA developed debilitating dyspnea and worsening obstruction on spirometry (FEV1 = 37% predicted) despite treatment with systemic steroids, rituximab, and cyclophosphamide. Bronchoscopy was performed, revealing membranous obliteration of the segmental bronchi of the right upper lobe (RUL) and superior segment of the left lower lobe (LLL) and diffuse bronchial stenosis. computed tomography (CT) chest showed RUL atelectasis and right lower lobe (RLL) bronchiectasis. He was referred for management of bronchial stenosis. Flexible bronchoscopy was performed in our hybrid operating room in collaboration with our colleagues from interventional radiology, where we had access to an Intraoperative C-arm cone beam CT and fluoroscopy. Bronchoscopy performed using an Olympus 4.2 mm video bronchoscope (BF-P190) with a 2.0 mm working channel identified membranous occlusion of the three RUL segments and severe stenosis of the bronchus intermedius, right middle lobe (RML), left mainstem bronchus (LMSB), left upper lobe (LUL), and lingula, and occlusion of the LLL superior segment (Figure 1A–D). A 21-gauge PeriView Flex Olympus needle was advanced via the working channel under fluoroscopic guidance to traverse the membrane of the obliterated bronchi in the RUL (Figure 2A,D). Once an opening was created in the membrane, the Olympus 1.9 mm EndoJaw biopsy forceps were traversed in a closed position through the small hole created by the needle, and then opened and pulled back to enlarge the opening. Then, a 0.018 Boston Scientific Thruway guidewire was introduced through a five French Cobra catheter to help direct the guidewire, and was advanced in tandem via the endotracheal tube alongside the bronchoscope through the opening (Figure 2B,E). Balloon dilation was performed over this guidewire, with a 4 mm and 6 mm × 2 cm monorail balloon catheter, with the balloon inflated up to 10–12 atmospheres until the waist in the balloon was eliminated for 2 min (Figure 2C,F). The LLL superior segment was similarly recannulated (Figure 2G–L), however, the guidewire was passed through the PeriView needle while inserted through the working channel. The needle was removed over the guidewire, and a 6 mm × 2 cm balloon was passed over the guidewire, though the working channel of the bronchoscope, while leaving the bronchoscope in place for visualization. Following re-expansion of the RUL, which was found to be severely bronchiectatic, the patient developed a pneumothorax that was evacuated with a pigtail and resolved within 24 h. Unfortunately, on follow-up evaluations, the openings to the RUL were completely obliterated (Figure 1E). Over the following weeks, he underwent dilations of the bronchus intermedius, RML, LMSB, LUL, and lingula (Figure 1E–H), which were similarly dilated over multiple procedures with balloons up to 12 mm in diameter through the working channel of the 4.2 mm bronchoscope. Before balloon dilations, kenalog (40 mg in 1 mL solution) was injected via the PeriView needle into the stenotic segments. Following balloon dilations, a 1.1 or 1.7 mm flexible cryoprobe (Erbe) was used to perform tissue devitalization using 60 s freeze cycles. There were no other occurrences of air leak, no significant bleeding, mucosal lacerations or perforations, and no episodes of hypoxemia. Following serial dilations, his FEV1 improved to 73% predicted, and he's had near complete resolution of his exertional dyspnea. He is currently undergoing monthly surveillance bronchoscopy. Multilevel bronchial stenosis is a rare and potentially life-threatening manifestation of GPA in children, and its management remains challenging.2 While there is growing interest in pediatric interventional bronchoscopy, with increasing applications being recognized,3 the use of interventional bronchoscopic tools in children can be limited by their smaller airway size and smaller working channel of pediatric bronchoscopes.4 The optimal approach to managing bronchial stenosis in children remains unknown, often requiring repeated bronchoscopic interventions with the primary objective to maintain intraluminal patency.5 Balloon dilation for stenotic airway diseases in children has been previously described mainly for subglottic and tracheal stenosis,6 however, data on the treatment of bronchial obstruction in children is limited.1 Angioplasty balloon catheters are the most widely used for bronchial balloon dilation in children, and have been described in conjunction with intralesional steroids, application of topical mitomycin C, laser treatment, cryotherapy, and stent placement.1, 2, 7 Given the challenges of treating progressive multilevel bronchial stenosis in GPA, it has been previously suggested that the use of cryotherapy via flexible bronchoscopy for cryodevitalization may be of particular benefit in patients with GPA to prevent scarring and decrease the risk of recurrence.7, 8 Reports have established the safety of balloon dilation in pediatric age patients for treating tracheobronchial stenosis.1 To our knowledge, this is the first reported case in a child of using a flexible bronchoscope needle to create an opening in an occlusive bronchial membrane to permit passage of a guidewire for balloon dilation. With this approach, we successfully advanced the angioplasty balloon catheters both in parallel and through the working channel of the 4.2 mm bronchoscope to perform balloon dilation of several bronchial segments without complication. This technique for the management of bronchial stenosis with balloon dilation via the working channel of the bronchoscope to the level of the segmental bronchi can be adopted to any young child who can accommodate a 4.2 mm bronchoscope, and when balloon dilation is performed in parallel with the bronchoscope, it is even feasible in any pediatric patient that can accommodate an even smaller bronchoscope of any size. Patient-specific considerations on selecting equipment size, including the choice of angioplasty balloon size poses additional challenges in children. Additional risks include maintaining adequate oxygenation and ventilation, prolonged procedure time, and airway trauma including laceration, perforation, and bleeding.1 In our patient, the lack of alternative treatment options coupled with debilitating dyspnea and obstruction prompted the necessity of this intervention. This undertaking should only be considered in specialized centers with appropriate bronchoscopy experience and can successfully result in increased airway diameter thereby immediately improving symptoms. Our case also highlights the importance of interdisciplinary and multicenter collaborations in the advancement of pediatric interventional bronchoscopy. Carolyn Wallace: Writing—review and editing; resources. Nicole Hilvert: Writing—review and editing; Resources. Evans M. Machogu: Writing—review and editing. Pi Chun Cheng: Writing—review and editing. Olivia A. Kwan: Writing—review and editing. Douglas C. von Allmen: Writing—review and editing; methodology; conceptualization. John M. Racadio: Conceptualization; writing—review and editing; supervision; methodology; visualization. Erik Hysinger: Conceptualization; writing—review and editing; supervision; methodology; visualization. The authors declare no conflict of interest.

Supplementary Table S1. Dose administered based on post-injection titers.

Interventional radiology (IR) physicians often face ergonomic challenges. Ideal positioning of imaging monitors and x-ray system controls in many IR and hybrid OR cases may not be possible due to physical obstruction from the c-arm and ancillary equipment. This study evaluates the clinical usability and effect on workflow of an augmented reality (AR) head mounted display (HMD) during IR procedures in a hybrid OR.

Deep vein thrombosis is a major source of morbidity and mortality worldwide. Catheter-directed thrombolytics are the frontline approach for vessel recanalization, though fibrinolytic efficacy is limited for stiff, chronic thrombi. Although thrombin has been used in preclinical models to induce thrombosis, the effect on lytic susceptibility and clot stiffness is unknown. The goal of this study was to explore the effect of bovine thrombin concentration and incubation time on lytic susceptibility and stiffness of porcine whole blood clots in vitro. Porcine whole blood was allowed to coagulate at 37°C in glass pipets primed with 2.5 or 15 U/mL thrombin for 15 to 120 min. Lytic susceptibility to recombinant tissue plasminogen activator (rt-PA, alteplase) over a range of concentrations (3.15-107.00 µg/mL) was evaluated using percentage clot mass loss. The Young's moduli and degrees of retraction of the clots were estimated using ultrasound-based single-track-location shear wave elasticity and B-mode imaging, respectively. Percentage mass loss decreased and clot stiffness increased with the incubation period. Clots formed with 15 U/mL and incubated for 2 h exhibited properties similar to those of highly retracted clots: Young's modulus of 2.39 ± 0.36 kPa and percentage mass loss of 8.69 ± 2.72% when exposed to 3.15 µg/mL rt-PA. The histological differences between thrombin-induced porcine whole blood clots in vitro and thrombi in vivo are described.

BACKGROUND AND PURPOSE: Selective ophthalmic artery infusion chemotherapy has improved ocular outcomes in children with retinoblastoma. Our aim was to correlate quantitative tumor reduction and dichotomous therapeutic response with technical and adjunctive factors during selective ophthalmic artery infusion chemotherapy for retinoblastoma. An understanding of such factors may improve therapeutic efficacy. MATERIALS AND METHODS: All patients with retinoblastoma treated by selective ophthalmic artery infusion chemotherapy at a single center during a 9-year period were reviewed. Only first-cycle treatments for previously untreated eyes were studied. Adjunctive factors (intra-arterial verapamil, intranasal oxymetazoline external carotid balloon occlusion) and technical factors (chemotherapy infusion time, fluoroscopy time) were documented by medical record review. Quantitative tumor reduction was determined by blinded comparison of retinal imaging acquired during examination under anesthesia before and 3?4?weeks after treatment. The dichotomous therapeutic response was classified according to quantitative tumor reduction as satisfactory (? 50%) or poor (<50%). RESULTS: Twenty-one eyes met the inclusion criteria. Patients ranged from 2 to 59?months of age. Adjuncts included intra-arterial verapamil in 15, intranasal oxymetazoline in 14, and external carotid balloon occlusion in 14. Quantitative tumor reduction ranged from 15% to 95%. Six showed poor dichotomous therapeutic response. A satisfactory dichotomous therapeutic response was correlated with intra-arterial verapamil (P = .03) in the aggregate cohort and in a subgroup undergoing treatment with single-agent melphalan?at a dose of <5?mg (P = .02). In the latter, higher average quantitative tumor reduction correlated with intra-arterial verapamil (P?<?.01). CONCLUSIONS: Intra-arterial verapamil during selective ophthalmic artery infusion chemotherapy is correlated with an improved therapeutic response, particularly when treating with lower doses of single-agent melphalan.

Adjuvant ultrasound at 2 MHz with or without an ultrasound contrast agent improves the rate of thrombus resolution by recombinant tissue plasminogen activator (rt-PA) in laboratory and clinical studies. A sub-megahertz approach can further expand this therapy to a subset of patients with an insufficient temporal bone window, improving efficacy in unselected patient populations. The aim of this study was to determine if a clinical ultrasound contrast agent (UCA), Definity, and 220 kHz pulsed ultrasound accelerated rt-PA thrombolysis in a preclinical animal model of vascular occlusion. The effect of Definity and ultrasound on thrombus clearance was first investigated in vitro and subsequently tested in a xenographic porcine cerebral thromboembolism model in vivo. Two different microcatheter designs (end-hole, multi-side-hole) were used to infuse rt-PA and Definity at the proximal edge or directly into clots, respectively. Sonothrombolysis with Definity increased clot mass loss relative to saline or rt-PA alone in vitro, only when rt-PA was administered directly into clots via a multi-side-hole microcatheter. Combined treatment with rt-PA, Definity, and ultrasound in vivo increased the rate of reperfusion up to 45 min faster than clots treated with rt-PA or saline. In this porcine cerebral thromboembolism model employing retracted human clots, 220 kHz ultrasound, in conjunction with Definity increased the probability of early successful reperfusion with rt-PA.

Background The safe and accurate placement of pedicle screws remains a critical step in open and minimally invasive spine surgery, emphasizing the need for intraoperative guidance techniques. Diffuse reflectance spectroscopy (DRS) is an optical sensing technology that may provide intraoperative guidance in pedicle screw placement. Purpose The study presents the first in vivo minimally invasive procedure using DRS sensing at the tip of a Jamshidi needle with an integrated optical K-wire. We investigate the effect of tissue perfusion and probe-handling conditions on the reliability of fat fraction measurements for breach detection in vivo. Methods A Jamshidi needle with an integrated fiber-optic K-wire was gradually inserted into the vertebrae under intraoperative image guidance. The fiber-optic K-wire consisted of two optical fibers with a fiber-to-fiber distance of 1.024 mm. DRS spectra in the wavelength range of 450 to 1600 nm were acquired at several positions along the path inside the vertebrae. Probe-handling conditions were varied by changing the amount of pressure exerted on the probe within the vertebrae. Continuous spectra were recorded as the probe was placed in the center of the vertebral body while the porcine specimen was sacrificed via a lethal injection. Results A typical insertion of the fiber-optic K-wire showed a drop in fat fraction during an anterior breach as the probe transitioned from cancellous to cortical bone. Fat fraction measurements were found to be similar irrespective of the amount of pressure exerted on the probe ( p = 0.65). The 95% confidence interval of fat fraction determination was found in the narrow range of 1.5–3.6% under various probe-handling conditions. The fat fraction measurements remained stable during 70 min of decreased blood flow after the animal was sacrificed. Discussions These findings indicate that changes in tissue perfusion and probe-handling conditions have a relatively low measureable effect on the DRS signal quality and thereby on the determination of fat fraction as a breach detection signal. Conclusions Fat fraction quantification for intraoperative pedicle screw breach detection is reliable, irrespective of changes in tissue perfusion and probe-handling conditions.

Safe and accurate placement of spinal screws remains a critical step during open and minimally invasive spinal fusion surgery. We investigated the application of diffuse reflectance spectroscopy (DRS) for real-time instrument guidance during a spinal screw placement procedure. A custom-built screw probe with integrated optical fibers was inserted into a vertebra under image guidance in an ex vivo human setting. We found that fat content derived from the spectra gradually changed as the probe approached the cortical bone boundary. The results indicate that DRS integrated into surgical instruments has the potential to improve the safety and accuracy of spinal screw placement procedures.

Safe and accurate placement of pedicle screws remains a critical step in open and minimally invasive spine surgery. The diffuse reflectance spectroscopy (DRS) technique may offer the possibility of intra-operative guidance for pedicle screw placement. Currently, Magnetic Resonance Imaging (MRI) is one of the most accurate techniques used to measure fat concentration in tissues. Therefore, the purpose of this study is to compare the accuracy of fat content measured invasively in vertebrae using DRS and validate it against the Proton density fat fraction (PDFF) derived via MRI. Chemical shift-encoding-based water-fat imaging of the spine was first performed on six cadavers. PDFF images were computed and manually segmented. 23 insertions using a custom-made screw probe with integrated optical fibers were then performed under cone beam computer tomography (CBCT). DR spectra were recorded at several positions along the trajectory as the optical screw probe was inserted turn by turn into the vertebral body. Fat fractions determined via DRS and MRI techniques were compared by spatially correlating the optical screw probe position within the vertebrae on CBCT images with respect to the PDFF images. The fat fraction determined by DRS was found to have a high correlation with those determined by MRI, with a Pearson coefficient of 0.950 (P< 0.001) as compared with PDFF measurements calculated from the MRI technique. Additionally, the two techniques were found to be comparable for fat fraction quantification within vertebral bodies (R2 = 0.905).

OBJECTIVE: The goal of this study was to develop and validate a system for automatic segmentation of the spine, pedicle identification, and screw path suggestion for use with an intraoperative 3D surgical navigation system.METHODS: Cone-beam CT (CBCT) images of the spines of 21 cadavers were obtained. An automated model-based approach was used for segmentation. Using machine learning methodology, the algorithm was trained and validated on the image data sets. For measuring accuracy, surface area errors of the automatic segmentation were compared to the manually outlined reference surface on CBCT. To further test both technical and clinical accuracy, the algorithm was applied to a set of 20 clinical cases. The authors evaluated the system's accuracy in pedicle identification by measuring the distance between the user-defined midpoint of each pedicle and the automatically segmented midpoint. Finally, 2 independent surgeons performed a qualitative evaluation of the segmentation to judge whether it was adequate to guide surgical navigation and whether it would have resulted in a clinically acceptable pedicle screw placement.RESULTS: The clinically relevant pedicle identification and automatic pedicle screw planning accuracy was 86.1%. By excluding patients with severe spinal deformities (i.e., Cobb angle > 75° and severe spinal degeneration) and previous surgeries, a success rate of 95.4% was achieved. The mean time (± SD) for automatic segmentation and screw planning in 5 vertebrae was 11 ± 4 seconds.CONCLUSIONS: The technology investigated has the potential to aid surgeons in navigational planning and improve surgical navigation workflow while maintaining patient safety.

Purpose of Review As imaging technologies expand to include image-guided anatomical navigation and surgical techniques evolve to accommodate increasingly complex interventions with minimally invasive approaches, interventionalists and surgeons have convened in a novel area of hospitals around the world, the hybrid operating room. Although these assets have long been used for cardiovascular procedures, the integration of these tools in a designated surgery suite has given rise to a variety of novel interventions and multi-specialty collaborations. Recent Findings In this review, we highlight current international hybrid room experiences in many fields, spanning from neurosurgery to urology. We also comment on our institutional journey of surgery-interventional radiology collaborations in developing our image-guided surgery program for a pediatric population. Summary As the hybrid operating room continues to gain traction globally, surgeons and interventional radiologists’ creativity and collaborative problem-solving skills will continue to be pushed to improve patient care. Identifying practice gaps and collaborating with industry is vital for further refinement of these tools.

Safe and accurate placement of screws remains a critical issue in open and minimally invasive spine surgery. We propose to use diffuse reflectance (DR) spectroscopy as a sensing technology at the tip of a surgical instrument to ensure a safe path of the instrument through the cancellous bone of the vertebrae. This approach could potentially reduce the rate of cortical bone breaches, thereby resulting in fewer neural and vascular injuries during spinal fusion surgery. In our study, DR spectra in the wavelength ranges of 400 to 1600 nm were acquired from cancellous and cortical bone from three human cadavers. First, it was investigated whether these spectra can be used to distinguish between the two bone types based on fat, water, and blood content along with photon scattering. Subsequently, the penetration of the bone by an optical probe was simulated using the Monte-Carlo (MC) method, to study if the changes in fat content along the probe path would still enable distinction between the bone types. Finally, the simulation findings were validated via an experimental insertion of an optical screw probe into the vertebra aided by x-ray image guidance. The DR spectra indicate that the amount of fat, blood, and photon scattering is significantly higher in cancellous bone than in cortical bone (p < 0.01), which allows distinction between the bone types. The MC simulations showed a change in fat content more than 1 mm before the optical probe came in contact with the cortical bone. The experimental insertion of the optical screw probe gave similar results. This study shows that spectral tissue sensing, based on DR spectroscopy at the instrument tip, is a promising technology to identify the transition zone from cancellous to cortical vertebral bone. The technology therefore has the potential to improve the safety and accuracy of spinal screw placement procedures. (C) The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License.