Catheter Trajectory Research Articles

Ultrasound Monitoring of Umbilical Catheters in the Neonatal Intensive Care Unit-A Prospective Observational Study.

Introduction: Umbilical catheterization provides a quick yet demanding central line that can lead to complications seen nowhere else. The aim of our study was to determine whether the repeated ultrasound scanning can influence the catheterization time, prevent some of the catheter-related complications, support the decision-making process and allow prolonged catheterization in patients without an alternative central access route.Methods: A prospective observational study was performed in a tertiary neonatal intensive care unit. A total of 129 patients and 194 umbilical catheters (119 venous and 75 arterial) were analyzed with a total of 954 scans. Ultrasound screening consisted of 1) assessing the catheter tip, location, movability, and surface and 2) analyzing the catheter trajectory. The outcome variables were defined as 1) catheter dislocation and 2) associated thrombosis.Results: Dislocation of catheter throughout the whole catheterization period was observed in 68% (81/119) of UVCs and 23% (17/75) of UACs. Thrombotic complications were observed in 34.5% (41/119) of UVCs and 12% (9/75) of UACs. 1/3 of UAC-associated thrombi were visible only after catheter removal. 51% (61/119) of UVC patients and 8% (6/75) of UAC patients made a clinical decision regarding the obtained catheter image.Conclusion: Bedside ultrasound imaging of catheters supports the decision-making process related to the catheterization duration, shortening the time if abnormalities are detected and allowing a safer prolonged UC stay when an alternative central line cannot be inserted.

Optimizing accuracy of freehand cannulation of the ipsilateral ventricle for intracranial pressure monitoring in patients with brain trauma.

Intracranial pressure (ICP) monitoring in traumatic brain injury (TBI) usually requires the placement of a catheter into the ipsilateral ventricle. This surgical procedure is commonly performed via a freehand method using surface anatomical landmarks as guides. The current accuracy of the catheter placement remains relatively low and even lower among TBI patients. This study was undertaken to optimize the freehand ventricular cannulation to increase the accuracy for TBI. The authors hypothesized that an optimal surgical plan of cannulation should give an operator the greatest degrees of freedom, which could be measured as the range of operation angle, range of catheter placement depth, and size of the target area. An imaging simulation was first performed using the computed tomography (CT) images of 47 adult patients with normal brain anatomy. On the reconstructed 3D head model, four different coronal planes of ventricular cannulation were identified: a 4-cm anterior, a 2-cm anterior, a standard (central), and a 2-cm posterior plane. The degrees of freedom during the cannulation procedure were determined, including the relevant angles, lengths of cannulation, cross-sectional area, and bounding rectangle of the lateral ventricle. Next, a retrospective assessment was performed on the CT scans of another 111 patients with TBI who underwent freehand ventricular cannulation for ICP monitoring. Postoperative measurements were also performed based on CT images to calculate the accuracy and safety of catheter placement between coronal planes in practice. Our simulation results showed that the 2-cm anterior plane had more extensive degrees of freedom for ventricular cannulation, in terms of length of catheter trajectory (7% longer, P<0.001), cross-sectional area of the lateral ventricle (14% larger, P=0.046), and length of the lateral ventricle (17% wider, P<0.001) than that of the standard plane, while both the 4-cm anterior and 2-cm posterior planes did not offer advantages over the standard plane in these ways. The mean length range of catheter trajectory in the 2-cm anterior plane was 41 to 58 mm. Retrospective assessment of TBI patients with ICP monitor placement also confirmed our simulation data. It showed that the accuracy of ipsilateral ventricle cannulation in the 2-cm anterior plane was 70.6%, which was a significant increase from 42.9% in the standard plane (P=0.007). Our imaging simulation and retrospective study demonstrate that different coronal planes could provide different degrees of freedom for cannulation, the 2-cm anterior plane has the greatest degrees of freedom in terms of larger target area and greater length range of the trajectory. The optimized surgical plan in this manner could improve cannulation accuracy and benefit a significant number of TBI patients.

Emergency Free-Hand Bedside Catheter Evacuation of Large Intracerebral Hematomas Following Thrombolysis for Ischemic Stroke: A Case Series

Symptomatic intracerebral hemorrhage (sICH) following systemic thrombolysis for ischemic stroke is often devastating, and open surgical evacuation is considered dangerous due to the increased risk of perioperative bleeding, and stereotactic placement of a catheter is too time-consuming. We therefore evaluated the feasibility of a free-hand bedside catheter technique for emergency hematoma evacuation. Patients who had a supratentorial sICH after thrombolysis, a hematoma volume > 30ml, and an ensuing reduction in vigilance were consecutively treated with acute minimally invasive catheter hematoma evacuation. Catheter insertion and trajectory were planned via 3D-reconstructed computed tomography (CT) scan, and free-hand insertion of an external ventricular catheter into the core of the hematoma was performed bedside, followed by careful blood aspiration. Cranial CT was used to verify catheter position and residual hematoma volume. In cases, where the residual volume exceeded 15ml, urokinase (5000IE) was administered into the clot every 6h until the volume decreased to < 15ml. In all six patients, catheter aspiration immediately reduced hematoma volume by 77%, from 73 ± 20ml to 17 ± 16ml (p = 0.028). In four patients, the hematoma was almost completely removed (< 10ml) by singular aspiration. In the remaining two patients with a residual hematoma size > 15ml, consecutive urokinase application resulted in a further reduction to 1ml and 15ml, respectively, after 30h. The median National Institues of Health Stroke Scale/Score after sICH was 19.5 points, rapidly decreasing to 11 after catheter aspiration (p = 0.027), and further improving to 4 at discharge. No procedure-related complications were observed. Emergency free-hand bedside catheter aspiration is a reasonable option for hematoma evacuation in large thrombolysis-associated sICH when performed by experienced neurosurgeons. Larger studies would help in determining the generalizability of our findings to other centers and assessing their impact on functional outcome.

Quantitative Analysis of 3D Artery Volume Reconstructions Using Biplane Angiography and Intravascular OCT Imaging.

Diameter and volume are frequently used parameters for cardiovascular diagnosis, e.g., to identify a stenosis of the coronary arteries. Intra-vascular OCT imaging has a high spatial resolution and promises accurate estimates of the vessel diameter. However, the actual images are reconstructed from A-scans relative to the catheter tip and imaging is subject to rotational artifacts. We study the impact of different volume reconstruction approaches on the accuracy of the vessel shape estimate. Using X-ray angiography we obtain the 3D vessel centerline and the 3D catheter trajectory, and we propose to align the A-scans using both. For comparison we consider reconstruction along a straight line and along the centerline. All methods are evaluated based on an experimental setup using a clinical angiography system and a vessel phantom with known shape. Our results illustrate potential pitfalls in the estimation of the vessel shape, particularly when the vessel is curved. We demonstrate that the conventional reconstruction approaches may result in an overestimate of the cross-section and that the proposed approach results in a good shape agreement in general and for curver segments, with DICE coefficients of approximately 0.96 and 0.98, respectively.

The importance of aspirin, catheterization accuracy, and catheter design in external ventricular drainage-related hemorrhage: a multicenter study of 1002 procedures.

External ventricular drainage (EVD) is the commonest neurosurgical procedure performed in daily neurosurgical practice, but relatively few studies have investigated the incidence and risk factors of its related hemorrhagic complications. This was a multicenter retrospective review of consecutive EVD procedures. Patients 18years or older who underwent EVD and had aroutine postoperative computed tomography (CT) scan performed within 24hours were included. EVD-related hemorrhage was defined as new intracranial hemorrhage immediately adjacent or within the ventricular catheter trajectory. The volume of hemorrhage and the position of the catheter tip were assessed. A review of patient-, disease-, and surgery-related factors including the ventricular catheter design utilized was conducted. The Bonferroni correction was applied to the alpha level of significance (0.05) for multivariable analysis. Nine hundred sixty-two patients underwent 1002 EVD performed by neurosurgeons in the operating theater. Sixteen percent (154) of patients were on aspirin before the procedure. Thirty-four percent (333) of patients had intracerebral hemorrhage, 25% (251) had aneurysmal subarachnoid hemorrhage and 16% (158) had traumatic brain injury. The mean duration from EVD to the first postoperative CT scan was 20 ± 4h. EVD-related hematomas were detected after 81 procedures with a per-catheter risk of 8.1%. Mean hematoma volume was 1.2 ± 3.3ml. Most were less than 1ml (grade I, 79%, 64), 1 to 15ml (grade II) in 20% (16) and a single clot larger than 15ml (grade III, 1%) were detected. Clinically significant hemorrhage that resulted in catheter occlusion occurred in 1.7% (17) of procedures. Most catheters (62%, 625) were optimally placed, i.e., its tip being within the ipsilateral frontal horn or third ventricle. Three non-antibiotic-impregnatedventricular catheter designs were used with 55% (550) being the 2.2-mm Integra™ catheter, 14% (137) being the 2.8-mm Medtronic™ catheter, and 31% (315) being the 3.1-mm Codman™ catheter. Independent significant predictors for EVD-related hemorrhage were the preoperative prescription of aspirin (adjusted OR 1.94; 95% CI 1.10-3.44), catheter malposition (aOR 1.99; 95% CI 1.22-3.23), and use of the 2.8-mm Medtronic™ catheter (aOR 4.22; 95% CI 2.39-7.41). The per-catheter risk of hemorrhage was 8.1%, but the incidence of symptomatic hemorrhage was low. The only patient risk factor was aspirin intake. This is the first study to evaluate and establish an association between catheter malposition and catheter design with EVD-related hemorrhage.

Catheter guided cerebral glioma resection combined with awake craniotomy: its usefulness and surgical outcome

Purpose: A challenging aspect of glioma surgery is to distinguish tumour tissue from surrounding eloquent structures and perform resection with accuracy. Various technologies have been used to address this issue including neuronavigator, intraoperative magnetic resonant imaging, intraoperative ultrasound, and fluorescence, each of which has certain drawbacks and limitations. In this study, authors demonstrate the technique of using stereotactically placed catheters as guidance during cerebral glioma resection and report the surgical outcomes.Materials and methods: This study included patients with intrinsic cerebral tumour adjacent to the eloquent structures. Catheter trajectories were planned using three-dimensional cerebral reconstruction on navigation software and catheters were stereotactically placed to mark the intended extent of resection. All craniotomies were performed in awake fashion under neurophysiologic mapping and continuous physical examination for safe maximal resection. Clinical outcome and intended versus actual extent of resection were analysed.Results: Between January 2015 and December 2016, 15 consecutive patients (8 males and 7 females) with intrinsic cerebral tumour underwent craniotomy with this technique. Median age was 43 years. Seven patients (46.7%) had worsening neurological status within 24 h postoperatively. Of these 7 patients, 6 patients (85.7%) regained preoperative neurological status by 6 months. The intended extent of resections were total, subtotal and partial in 3 (20%), 9 (60%), and 3 (20%) patients, respectively. The actual extent of resections were total, subtotal and partial in 3 (20%), 8(53.3%), and 4 (26.7%) patients, respectively. There were no catheter related complications. There was no 30-day postoperative mortality.Conclusions: Catheter guided resection along with awake surgery and neurophysiologic monitoring is a valid technique for infiltrative tumour, especially for ones locating near eloquent structures where the margin of error is low. This is a simple and economical technique which requires only standard equipment widely available to neurosurgical operating theatres.

Stereotactic Placement of Intratumoral Catheters for Continuous Infusion Delivery of Herpes Simplex Virus -1 G207 in Pediatric Malignant Supratentorial Brain Tumors

The engineered herpes simplex virus-1 G207, is a promising therapeutic option for central nervous system tumors. The first-ever pediatric phase 1 trial of continuous-infusion delivery of G207 via intratumoral catheters for recurrent or progressive malignant brain tumors is ongoing. In this article, we describe surgical techniques for the accurate placement of catheters in multiple supratentorial locations and perioperative complications associated with such procedures. A prospective study of G207 in children with recurrent malignant supratentorial tumors is ongoing. Preoperative stereotactic protocol magnetic resonance imaging was performed, and catheter trajectories planned using StealthStation planning software. Children underwent placement of 3-4 silastic catheters using a small incision burr hole and the Vertek system. Patients had a preinfusion computed tomography scan to confirm correct placement of catheters. Six children underwent implantation of 3-4 catheters. Locations of catheter placement included frontal, temporal, parietal, and occipital lobes, and the insula and thalamus. There were no clinically significant perioperative complications. Postoperative computed tomography scans coupled with preoperative MRI scans demonstrated accurate placement of 21 of 22 catheters, with 1 misplaced catheter pulled back to an optimal location at the bedside. One patient had hemorrhage along the catheter tract that was clinically asymptomatic. Another patient had cerebrospinal fluid leak from a biopsy incision 9 days after surgery that was oversewn without complication. The placement of multiple intratumoral catheters in pediatric patients with supratentorial tumors via frameless stereotactic techniques is feasible and safe. Intratumoral catheters provide a potentially effective route for the delivery of G207 and may be employed in other trials utilizing oncolytic virotherapy for brain tumors.

Hemorrhagic Complications of External Ventriculostomy in the Aspirin and P2Y12 Response Assay Era

Hemorrhagic complications reported from external ventricular drain (EVD) placement range from 10% to 44%. There remains limited literature investigating the incidence, risk factors, and mechanisms to prevent its occurrence, especially in the setting of antiplatelet agent use. We investigated EVD-related hemorrhagic complications after the implementation of VerifyNow platelet inhibition assays at our institution. Medical records from 445 patients requiring EVD placement during a 2-year period during which our institution used the assays were reviewed. In total 345 patients were included, and 208 of them underwent assay testing. Indications for EVD included complications of cerebrovascular disease (n= 215), traumatic brain injury (n= 74), primary hydrocephalus (n= 23), and tumor (n= 33). Hemorrhage was defined as any new area of hyperdensity adjacent to or immediately along the catheter trajectory on computed tomography. There was no significant decrease in catheter-induced hemorrhage (CIH) between patients who underwent the VerifyNow assay and those who did not. Platelet transfusion did not significantly decrease the risk of CIH. CIH occurred in 17.7% of patients, significantly decreased when compared with our previously published incidence of 33% before platelet inhibition assay use (P < 0.05). Patients with cerebrovascular disease complications exhibited a significant decrease in CIH, 20% versus 39%, before assay use (P < 0.01). The incidence of hemorrhage is lower in our new cohort when compared with that of our previously published cohort. Despite the overall decreased rate of hemorrhage, there was no significant difference in hemorrhage rates between patients who did or did not undergo the assay. Platelet transfusion did not decrease the incidence of hemorrhage in patients with inhibited platelet function.

Validation of a Novel System for Co-Registration of Coronary Angiographic and Intravascular Ultrasound Imaging.

Intravascular ultrasound (IVUS) is a useful adjunct to guide percutaneous coronary intervention (PCI). Correlating IVUS images with angiographic findings can be challenging. We evaluated the utility of a novel co-registration system for IVUS and coronary angiography. A 3-D virtual catheter trajectory was constructed from separate angiographic imaging runs using bespoke software. Intravascular ultrasound images were obtained using a commercially available mechanical rotational transducer with motorized pullback. Co-registration of ultrasound and angiographic images was then performed retrospectively based on the length of pullback, the 3-D trajectory and the start position of the catheter. Validation was performed in a spherical phantom model and in vivo in the coronary circulation of patients undergoing coronary angiography and intravascular imaging for clinical purposes. 111 paired angiographic and IVUS runs were performed in 3 phantom models. The differences between the reference length and the length measured on the 3D reconstructed path was -0.01 ± 0.40 mm. Intra-observer variability was 0.4%. We enrolled 25 patients in 3 European hospitals and performed 35 co-registration attempts with an 86% success rate. 71 landmarks were selected by the first operator, 68 by the second. Differences between angiographic and IVUS landmarks were -0.22 ± 0.72 mm and 0.05 ± 1.01 mm, respectively. Inter-observer variability was 0.23 ± 0.63 mm. We present a novel method for the co-registration of IVUS and coronary angiographic images. This system performed well in a phantom model and using images obtained from the human coronary circulation. Innovation, intravascular ultrasound, other technique.

Intraoperative Ventriculostomy Using K Point in Surgical Management of Aneurysmal Subarachnoid Hemorrhage

Intraoperative ventriculostomy in the surgical management of aneurysmal subarachnoid hemorrhage (SAH) is frequently performed to reduce increased intracranial pressure. The previously suggested ventriculostomy points have some limitations because the dura mater must be opened to be accessed and it is difficult to measure the exact entry point in patients with brain edema. We propose a new intraoperative ventriculostomy point (Kpoint) for use in the surgical management of aneurysmal SAH patient with severe brain edema. We performed intraoperative ventriculostomy using the K point on 155 patients with aneurysmal SAH between January 2012 and August 2016. Before opening the dura mater following standard pterional craniotomy, we inserted the ventricular catheter through a small dural incision perpendicular to the middle frontal gyrus toward the ipsilateral medial epicanthus. We simulated the catheter trajectory using a commercial navigation system on 2 patients with brain tumor. Ventriculostomy related hemorrhage occurred in 12 patients (7.7%), but there were no large hemorrhages causing neurologic deterioration or requiring evacuation. No language impairment was observed in these patients. Analysis using the navigation system revealed that the trajectory of K point ventriculostomy avoided critical periventricular brain structures and passed through the space between the genu of the corpus callosum and head of the caudate nucleus. K point ventriculostomy allows for easy access to a target point and protects the brain during opening of the dura mater and drilling of the sphenoid bone.

Anatomic Investigation of the Trajectory for Stereotactic Laser Amygdalohippocampectomy.

Magnetic resonance imaging-guided laser interstitial thermal therapy (LITT) has emerged as a promising treatment for mesial temporal lobe epilepsy. Surgeons must understand the relevant anatomy that is traversed by the catheter and affected by ablation. To study the anatomic structures crossed by the LITT catheter until it reaches the amygdala. Three human cadaveric heads were implanted with catheters using a frameless stereotactic technique. The Visualase® system (Medtronic, Dublin, Ireland) was utilized to ablate along the trajectory. Coronal and oblique axial slices were created. Fiber tract dissections were performed in a lateral-medial and inferior-superior scheme. Magnetic resonance tractography was acquired to illustrate the tracts dissected. Entry points occurred within 4 cm of the transverse and sagittal sinus, inferior to the lambdoid suture. The cortex of the inferior occipital gyrus was crossed in the region of the transverse occipital sulcus. The vertical occipital fasciculus was crossed en route to passing through the optic radiations. The catheter crossed through or inferior to the optic radiations before piercing the parahippocampal gyrus at about 4 cm from the skull. The catheter entered the hippocampus as it pierced the superior margin of the parahippocampus at 6 cm. The catheter entered the head of the hippocampus to lie inferolateral to the amygdala in the last centimeter of the trajectory. Understanding the anatomic principles of LITT catheter trajectories will improve the ability to perform this procedure. The current study is the first to examine the anatomy of this trajectory and will serve as the basis for future studies.

Learning-based endovascular navigation through the use of non-rigid registration for collaborative robotic catheterization

PurposeEndovascular intervention is limited by two-dimensional intraoperative imaging and prolonged procedure times in the presence of complex anatomies. Robotic catheter technology could offer benefits such as reduced radiation exposure to the clinician and improved intravascular navigation. Incorporating three-dimensional preoperative imaging into a semiautonomous robotic catheterization platform has the potential for safer and more precise navigation. This paper discusses a semiautonomous robotic catheter platform based on previous work (Rafii-Tari et al., in: MICCAI2013, pp 369–377. https://doi.org/10.1007/978-3-642-40763-5_46, 2013) by proposing a method to address anatomical variability among aortic arches. It incorporates anatomical information in the process of catheter trajectories optimization, hence can adapt to the scale and orientation differences among patient-specific anatomies.MethodsStatistical modeling is implemented to encode the catheter motions of both proximal and distal sites based on cannulation data obtained from a single phantom by an expert operator. Non-rigid registration is applied to obtain a warping function to map catheter tip trajectories into other anatomically similar but shape/scale/orientation different models. The remapped trajectories were used to generate robot trajectories to conduct a collaborative cannulation task under flow simulations. Cross-validations were performed to test the performance of the non-rigid registration. Success rates of the cannulation task executed by the robotic platform were measured. The quality of the catheterization was also assessed using performance metrics for manual and robotic approaches. Furthermore, the contact forces between the instruments and the phantoms were measured and compared for both approaches.ResultsThe success rate for semiautomatic cannulation is 98.1% under dry simulation and 94.4% under continuous flow simulation. The proposed robotic approach achieved smoother catheter paths than manual approach. The mean contact forces have been reduced by 33.3% with the robotic approach, and 70.6% less STDEV forces were observed with the robot.ConclusionsThis work provides insights into catheter task planning and an improved design of hands-on ergonomic catheter navigation robots.

Functional Assessment of Stenotic Coronary Artery in 3D Geometric Reconstruction From Fusion of Intravascular Ultrasound and X-Ray Angiography

We aimed to present an alternative method for calculating fractional flow reserve (FFR) from 3-D reconstruction of a coronary artery, based on coronary (X-ray) angiography and intravascular ultrasound (IVUS), to evaluate the ischemic-risk of stenosis and the relationship between FFR and geometrical features of the coronary lesion. The reconstruction of the 3-D catheter trajectory was obtained by the vertical intersection of spatial surfaces which were derived from the 2-D catheter curves in the angiography plane. Computational fluid dynamics was applied to calculate the hemodynamics in the coronary arteries and coronary flow-based FFR (fFFR) was obtained. Twenty-two stenotic coronary arteries were included in this paper for the evaluation of the proposed method. Good correlation between fFFR and the measured pressure wire-derived FFR was found ( F = 0.916 and P r = −0.784 and P < 0.01). However, fFFR had no significant correlation with coronary curvature, lesion length, and angle. Our method therefore provides a coronary vascular model-based means for computing FFR, and makes full use of the advantages of IVUS examination to diagnose the diseases.

A fast inverse treatment planning strategy facilitating optimized catheter selection in image-guided high-dose-rate interstitial gynecologic brachytherapy.

Interstitial high-dose rate (HDR) brachytherapy is an important therapeutic strategy for the treatment of locally advanced gynecologic (GYN) cancers. The outcome of this therapy is determined by the quality of dose distribution achieved. This paper focuses on a novel yet simple heuristic for catheter selection for GYN HDR brachytherapy and their comparison against state of the art optimization strategies. The proposed technique is intended to act as a decision-supporting tool to select a favorable needle configuration. The presented heuristic for catheter optimization is based on a shrinkage-type algorithm (SACO). It is compared against state of the art planning in a retrospective study of 20 patients who previously received image-guided interstitial HDR brachytherapy using a Syed Neblett template. From those plans, template orientation and position are estimated via a rigid registration of the template with the actual catheter trajectories. All potential straight trajectories intersecting the contoured clinical target volume (CTV) are considered for catheter optimization. Retrospectively generated plans and clinical plans are compared with respect to dosimetric performance and optimization time. All plans were generated with one single run of the optimizer lasting 0.6-97.4 s. Compared to manual optimization, SACO yields a statistically significant (P ≤ 0.05) improved target coverage while at the same time fulfilling all dosimetric constraints for organs at risk (OARs). Comparing inverse planning strategies, dosimetric evaluation for SACO and "hybrid inverse planning and optimization" (HIPO), as gold standard, shows no statistically significant difference (P > 0.05). However, SACO provides the potential to reduce the number of used catheters without compromising plan quality. The proposed heuristic for needle selection provides fast catheter selection with optimization times suited for intraoperative treatment planning. Compared to manual optimization, the proposed methodology results in fewer catheters without a clinically significant loss in plan quality. The proposed approach can be used as a decision support tool that guides the user to find the ideal number and configuration of catheters.

Adjustable Ghajar Guide Technique for Accurate Placement of Ventricular Catheters: A Pilot Study.

ObjectiveAn adjustable Ghajar guide is presented to improve the accuracy of the original Ghajar guide technique. The accuracy of the adjustable Ghajar guide technique is also investigated.MethodsThe coronal adjustment angle from the orthogonal catheter trajectory at Kocher’s point is determined based on coronal head images using an electronic picture archiving and communication system. For the adjustable Ghajar guide, a protractor is mounted on a C-shaped basal plate that is placed in contact with the margin of a burrhole, keeping the central 0° line of the protractor orthogonal to the calvarial surface. A catheter guide, which is moved along the protractor and fixed at the pre-determined adjustment angle, is then used to guide the ventricular catheter into the frontal horn adjacent to the foramen of Monro. The adjustable Ghajar guide technique was applied to 20 patients, while a freehand technique based on the surface anatomy of the head was applied to another 47 patients. The accuracy of the ventricular catheter placement was then evaluated using postoperative computed tomography scans.ResultsFor the adjustable Ghajar guide technique (AGT) patients, the bicaudate index ranged from 0.23 to 0.33 (mean±standard deviation [SD]: 0.27±0.03) and the adjustment angle ranged from 0° to 10° (mean±SD: 5.2°±3.2°). All the AGT patients experienced successful cerebrospinal fluid diversion with only one pass of the catheter. Optimal placement of the ventricular catheter in the ipsilateral frontal horn approximating the foramen of Monro (grade 1) was achieved in 19 patients (95.0%), while a suboptimal trajectory into a lateral corner of the frontal horn passing along a lateral wall of the frontal horn (grade 3) occurred in 1 patient (5.0%). Thus, the AGT patients experienced a significantly higher incidence of optimal catheter placement than the freehand catheterized patients (95.0% vs. 68.3%, p=0.024). Moreover, none of the AGT patients experienced any tract hemorrhages along the catheter or procedure-related complications.ConclusionThe proposed adjustable Ghajar guide technique, using angular adjustment in the coronal plane from the orthogonal trajectory at Kocher’s point, facilitates accurate freehand placement of a ventricular catheter for hydrocephalic patients.

Accurate model-based segmentation of gynecologic brachytherapy catheter collections in MRI-images.

The gynecological cancer mortality rate, including cervical, ovarian, vaginal and vulvar cancers, is more than 20,000 annually in the US alone. In many countries, including the US, external-beam radiotherapy followed by high dose rate brachytherapy is the standard-of-care. The superior ability of MR to visualize soft tissue has led to an increase in its usage in planning and delivering brachytherapy treatment. A technical challenge associated with the use of MRI imaging for brachytherapy, in contrast to that of CT imaging, is the visualization of catheters that are used to place radiation sources into cancerous tissue. We describe here a precise, accurate method for achieving catheter segmentation and visualization. The algorithm, with the assistance of manually provided tip locations, performs segmentation using image-features, and is guided by a catheter-specific, estimated mechanical model. A final quality control step removes outliers or conflicting catheter trajectories. The mean Hausdorff error on a 54 patient, 760 catheter reference database was 1.49 mm; 51 of the outliers deviated more than two catheter widths (3.4 mm) from the gold standard, corresponding to catheter identification accuracy of 93% in a Syed-Neblett template. In a multi-user simulation experiment for evaluating RMS precision by simulating varying manually-provided superior tip positions, 3σ maximum errors were 2.44 mm. The average segmentation time for a single catheter was 3 s on a standard PC. The segmentation time, accuracy and precision, are promising indicators of the value of this method for clinical translation of MR-guidance in gynecologic brachytherapy and other catheter-based interventional procedures.

Prospective Clinical Implementation of a Novel Magnetic Resonance Tracking Device for Real-Time Brachytherapy Catheter Positioning

We designed and built dedicated active magnetic resonance (MR)-tracked (MRTR) stylets. We explored the role of MRTR in a prospective clinical trial. Eleven gynecologic cancer patients underwent MRTR to rapidly optimize interstitial catheter placement. MRTR catheter tip location and orientation were computed and overlaid on images displayed on in-room monitors at rates of 6 to 16 frames per second. Three modes of actively tracked navigation were analyzed: coarse navigation to the approximate region around the tumor; fine-tuning, bringing the stylets to the desired location; and pullback, with MRTR stylets rapidly withdrawn from within the catheters, providing catheter trajectories for radiation treatment planning (RTP). Catheters with conventional stylets were inserted, forming baseline locations. MRTR stylets were substituted, and catheter navigation was performed by a clinician working inside the MRI bore, using monitor feedback. Coarse navigation allowed repositioning of the MRTR catheters tips by 16mm (mean), relative to baseline, in 14±5s/catheter (mean±standard deviation [SD]). The fine-tuning mode repositioned the catheter tips by a further 12mm, in 24±17s/catheter. Pullback mode provided catheter trajectories with RTP point resolution of ∼1.5mm, in 1 to 9s/catheter. MRTR-based navigation resulted in rapid and optimal placement of interstitial brachytherapy catheters. Catheters were repositioned compared with the initial insertion without tracking. In pullback mode, catheter trajectories matched computed tomographic precision, enabling their use for RTP.

DIPG-38. CORTICOSPINAL TRACT TOLERANCE TO CATHETER POSITIONING FOR CONVECTION ENHANCED DELIVERY IN THE BRAIN STEM

Abstract INTRODUCTION: Convection enhanced delivery (CED) has recently been explored as a therapeutic strategy for children with diffuse intrinsic pontine glioma (DIPG). An anterior or supratentorial approach for catheter positioning risks conflict with descending white matter bundles where they become concentrated in the internal capsule and crural pyramid. We describe our experience planning catheter trajectories in the context of eloquent structures and outcomes this patient population. METHODS: As part of a Phase 1 clinical trial using CED with 124I-8H9, a radiolabeled monoclonal antibody (NCT01502917), a flexible step-design infusion catheter (Brainlab Flexible Catheter, BrainLab, Munich, Germany) was surgically placed via a supratentorial approach. Surgical planning was conducted based on 3D T1, T2, and SWI sequences. A fully compatible MR-guidance platform was used for trajectory planning catheter deployment. A neurologic exam was performed immediately post-procedure, prior to initiating infusion, to assess for procedure-related deficits. Intra- and post-procedural MR images were analyzed for the anatomic position of catheter trajectories. Conflicts between the catheter tract and the posterior limb of the internal capsule and the pyramid of the crus cerebri were recorded. Correlation between motor deficits and the catheter path was evaluated. RESULTS: Thirty-three catheter insertions were performed for 28 children with DIPG. One patient experienced a slight worsening of an existing ipsilateral facial palsy likely related to the course of facial nerve fibers in the brainstem. The posterior limb of the internal capsule and the pyramid of the crus cerebri frequently overlapped the catheter tract without incident. CONCLUSIONS: Transgression of descending corticospinal motor tracts by catheters for intracranial infusion is acceptable. We observed that a supratentorial approach to the brainstem crossing eloquent fibers resulted in one neurologic deficit. There does not appear to be a functional risk requiring a need for avoidance of the dominant motor fiber tracts during trajectory planning.

Automated 3D coronary sinus catheter detection using a scanning-beam digital x-ray system.

Scanning-beam digital x-ray (SBDX) is an inverse geometry x-ray fluoroscopy system capable of tomosynthesis-based 3D tracking of catheter electrodes concurrent with fluoroscopic display. To facilitate respiratory motion-compensated 3D catheter tracking, an automated coronary sinus (CS) catheter detection algorithm for SBDX was developed. The technique uses the 3D localization capability of SBDX and prior knowledge of the catheter shape. Candidate groups of points representing the CS catheter are obtained from a 3D shape-constrained search. A cost function is then minimized over the groups to select the most probable CS catheter candidate. The algorithm was implemented in MATLAB and tested offline using recorded image sequences of a chest phantom containing a CS catheter, ablation catheter, and fiducial clutter. Fiducial placement was varied to create challenging detection scenarios. Table panning and elevation was used to simulate motion. The CS catheter detection method had 98.1% true positive rate and 100% true negative rate in 2755 frames of imaging. Average processing time was 12.7 ms/frame on a PC with a 3.4 GHz CPU and 8 GB memory. Motion compensation based on 3D CS catheter tracking was demonstrated in a moving chest phantom with a fixed CS catheter and an ablation catheter pulled along a fixed trajectory. The RMS error in the tracked ablation catheter trajectory was 1.41 mm, versus 10.35 mm without motion compensation. A computationally efficient method of automated 3D CS catheter detection has been developed to assist with motion-compensated 3D catheter tracking and registration of 3D cardiac models to tracked catheters.

Central venous access related adverse events after trabectedin infusions in soft tissue sarcoma patients; experience and management in a nationwide multi-center study

BackgroundTrabectedin has shown efficacy against soft tissue sarcomas (STS) and has manageable toxicity. Trabectedin is administered through central venous access devices (VAD), such as subcutaneous ports with tunneled catheters, Hickman catheters and PICC lines. Venous access related adverse events are common, but have not yet been reported in detail.MethodsA retrospective analysis of patient files of STS patients receiving trabectedin monotherapy between 1999 and 2014 was performed in all five STS referral centers in the Netherlands. This survey focused on adverse events related to the VAD and the actions taken in response to these events.ResultsIn the 127 patients included in this analysis, 102 venous access ports (VAP), 15 Hickman catheters and 10 PICC lines were used as primary means of central venous access. The most frequently reported adverse events at the VAD site were erythema (30.7%), pain (28.3%), inflammation (11.8%) and thrombosis (11.0%). Actions taken towards these adverse events include oral antibiotics (17.3%), VAD replacement (15.0%) or a wait-and-see policy (13.4%). In total, 45 patients (35.4%) with a subcutaneous port developed a varying degree of inflammation along the trajectory of the tunneled catheter. In all but three patients, this was a sterile inflammation, which was considered a unique phenomenon for trabectedin. Microscopic leakage of trabectedin along the venous access device and catheter was considered the most plausible cause for this adverse event. Placing the catheter deeper under the skin resolved the issue almost completely.ConclusionTrabectedin infusion commonly leads to central venous access related adverse events. Sterile inflammation along the catheter trajectory is one of the most common adverse events and can be prevented by placing the catheter deeper under the skin.