The Clinical and Radiological Outcomes of the Multimodal Use of The Woven EndoBridge (WEB) Device: A Large Multicentre Study.

BACKGROUND: The Woven EndoBridge (WEB) is a device used for intrasaccular flow diversion, designed for the elimination of wide-necked bifurcation aneurysms (WNBAs) from the circulation. In this study, we aim to assess the safety and efficacy of the WEB, and its uses in treating aneurysms of different morphologies and locations. METHODS: In a retrospective analysis, we compiled a comprehensive dataset from patients treated with the WEB device across three major Australian neurovascular centres from May 2017 to September 2023. The case series encompassed a spectrum of aneurysm types, including wide-necked bifurcation, sidewall, and irregularly shaped aneurysms, as well as cases previously managed with alternative therapeutic strategies. This study additionally encompasses cases where aneurysms were managed using the WEB device in combination with supplementary endovascular devices. RESULTS: The study included 169 aneurysms in 161 patients. The rate of satisfactory aneurysm occlusion was 85.6%, with 86.7% of patients maintaining good functional status at their most recent follow-up. The procedure exhibited a low mortality rate of 0.6% and a thromboembolic complication rate of 7.1% (n=12/161). There were no instances of post-operative re-rupture and the procedure-related haemorrhage rate was low (1.2%, n=2/169), aligning with the literature regarding the safety and efficacy of the WEB device. CONCLUSION: Our multicentre trial reinforces the WEB device's role as an effective and safe modality for intracranial aneurysm management, supporting its expanded application beyond WNBAs. Further prospective studies are required to delineate its evolving role fully.

Occult contrast retention post-thrombectomy on 24-h follow-up dual-energy CT: Associations and impact on imaging analysis.

BACKGROUND: Following reperfusion treatment in ischemic stroke, computed tomography (CT) imaging at 24 h is widely used to assess radiological outcomes. Even without visible hyperattenuation, occult angiographic contrast may persist in the brain and confound Hounsfield unit-based imaging metrics, such as net water uptake (NWU). AIMS: We aimed to assess the presence and factors associated with retained contrast post-thrombectomy on 24-h imaging using dual-energy CT (DECT), and its impact on the accuracy of NWU as a measure of cerebral edema. METHODS: Consecutive patients with anterior circulation large vessel occlusion who had post-thrombectomy DECT performed 24-h post-treatment from two thrombectomy stroke centers were retrospectively studied. NWU was calculated by interside comparison of HUs of the infarct lesion and its mirror homolog. Retained contrast was quantified by the difference in NWU values with and without adjustment for iodine. Patients with visible hyperdensities from hemorrhagic transformation or visible contrast retention and bilateral infarcts were excluded. Cerebral edema was measured by relative hemispheric volume (rHV) and midline shift (MLS). RESULTS: Of 125 patients analyzed (median age 71 (IQR = 61-80), baseline National Institutes of Health Stroke Scale (NIHSS) 16 (IQR = 9.75-21)), reperfusion (defined as extended-Thrombolysis-In-Cerebral-Infarction 2b-3) was achieved in 113 patients (90.4%). Iodine-subtracted NWU was significantly higher than unadjusted NWU (17.1% vs 10.8%, p < 0.001). In multivariable median regression analysis, increased age (p = 0.024), number of passes (p = 0.006), final infarct volume (p = 0.023), and study site (p = 0.021) were independently associated with amount of retained contrast. Iodine-subtracted NWU correlated with rHV (rho = 0.154, p = 0.043) and MLS (rho = 0.165, p = 0.033) but unadjusted NWU did not (rHV rho = -0.035, p = 0.35; MLS rho = 0.035, p = 0.347). CONCLUSIONS: Angiographic iodine contrast is retained in brain parenchyma 24-h post-thrombectomy, even without visually obvious hyperdensities on CT, and significantly affects NWU measurements. Adjustment for retained iodine using DECT is required for accurate NWU measurements post-thrombectomy. Future quantitative studies analyzing CT after thrombectomy should consider occult contrast retention.

Fat fraction quantification of bone marrow in the lumbar spine using the LiverLab assessment tool in healthy adult volunteers and patients with Gaucher disease.

BACKGROUND: Magnetic Resonance Imaging is used for evaluation of bone in Gaucher disease (GD), but a widely available quantitative scoring method remains elusive. AIMS: The study purpose was to assess the reproducibility of the LiverLab tool for assessing bone marrow fat fraction (FF) and determine whether it could differentiate GD patients from healthy subjects. METHODS: Ten healthy volunteers and 18 GD patients were prospectively recruited. FF was calculated at L3, L4 and L5. GD patient bone marrow burden (BMB) score assessed by one observer. Inter and intra-rater agreement assessed with Bland-Altman data plots. Differences in FF between healthy volunteers versus GD patients and between subjects treated versus not treated assessed using two-sample t-tests. In GD patients, the relationship between FF, BMB and glucosylsphingosine was determined using the Pearson's correlation coefficient. RESULTS: Healthy volunteer mean FF was 0.36, standard deviation (SD) 0.10 (range 0.20-0.57). Intra and inter-rater SD were both 0.02. GD patient mean FF was 0.40, SD 0.13 (range 0.09-0.57). No statistical difference was shown between healthy volunteers and GD patients (P = 0.447) or between GD patients whether on enzyme replacement therapy or not (P = 0.090). No significant correlation between mean FF and total BMB (r = -0.525, P = 0.253) or between FF and glucosylsphingosine levels (r = 0.287, P = 0.248). CONCLUSION: Excellent reproducibility of LiverLab FF measurements across studies and observers is comparable to Dixon quantitative chemical shift imaging (QCSI). Lack of statistical difference between GD patients and controls may be explained by limited patient numbers, active treatment or mild disease severity in untreated patients.

Necessity of performing a routine chest radiograph following the insertion of tunnelled Hickman catheter under imaging guidance: A single centre experience.

INTRODUCTION: A chest radiograph has traditionally been performed following the insertion of a tunnelled Hickman catheter to immediately exclude rare but potentially serious complications such as pneumothorax and haemothorax and confirm appropriate positioning of the catheter tip. The value of completing the routine chest radiograph has been questioned when fluoroscopic image may be easily obtained in the angiography suite for the same purpose, and the rate of iatrogenic pneumothorax remains extremely low in the Medical literature. We describe our experience of performing Hickman catheter insertion under ultrasound and fluoroscopic guidance and whether routinely performing the chest radiograph is justifiable. METHODS: A single centre retrospective review was performed of patients who received a tunnelled Hickman catheter and underwent postprocedural chest radiograph in the Interventional Radiology Department during a fifteen-year period from August 2007 to April 2021. Patient demographics and complications were documented. RESULTS: Delayed iatrogenic pneumothorax was diagnosed in one asymptomatic patient (0.06%) on a chest radiograph out of 1735 patients, and they required chest tube insertion. Other complications included two cases of right common carotid artery puncture, one case of right internal jugular vein dissection and one case of left internal jugular perforation. Two patients required a repeat procedure within 24 h due to superior migration of the Hickman catheter on chest radiograph. CONCLUSION: Given the extremely low rate of iatrogenic pneumothorax, chest radiograph following the insertion of a tunnelled Hickman catheter under ultrasound and fluoroscopic guidance may be an unnecessary investigation unless the patient is symptomatic, or there is sufficient clinical concern.

Indirect Lung Absorbed Dose Verification by 90Y PET/CT and Complete Lung Protection by Hepatic Vein Balloon Occlusion: Proof of Concept.

Postradioembolization lung absorbed dose verification was historically problematic and impractical in clinical practice. We devised an indirect method using 90Y PET/CT. Methods: Conceptually, true lung activity is simply the difference between the total prepared activity minus all activity below the diaphragm and residual activity within delivery apparatus. Patient-specific lung mass is measured by CT densitovolumetry. True lung mean absorbed dose is calculated by MIRD macrodosimetry. Results: Proof of concept is shown in a hepatocellular carcinoma patient with a high lung shunt fraction of 26%, where evidence of technically successful hepatic vein balloon occlusion for radioembolization lung protection was required. Indirect lung activity quantification showed the postradioembolization lung shunt fraction to be reduced to approximately 1% with a true lung mean absorbed dose of approximately 1 Gy, suggesting complete lung protection by hepatic vein balloon occlusion. Conclusion: We discuss possible clinical applications such as lung absorbed dose verification, refining the limits of lung tolerance, and the concept of massive activity radioembolization.

Learning Curve for Robot-Assisted Percutaneous Pedicle Screw Placement in Thoracolumbar Surgery.

STUDY DESIGN: Retrospective review of an initial cohort of consecutive patients undergoing robot-assisted pedicle screw placement. PURPOSE: We aimed to evaluate the learning curve, if any, of this new technology over the course of our experience. OVERVIEW OF LITERATURE: Percutaneous pedicle screws have specific advantages over open freehand screws. However, they require intraoperative imaging for their placement (e.g., fluoroscopy and navigation) and require increased surgeon training and skill with the learning curve estimated at approximately 20-30 cases. To our knowledge, this is the first study that measures the learning curve of robot-guided purely percutaneous pedicle screw placement with comprehensive objective postoperative computed tomography (CT) scoring, time per screw placement, and fluoroscopy time. METHODS: We included the first 80 consecutive patients undergoing robot-assisted spinal surgery at Melbourne Private Hospital. Data were collected for pedicle screw placement accuracy, placement time, fluoroscopy time, and revision rate. Patient demographic and relevant perioperative and procedural data were also collected. The patients were divided equally into four sub-groups as per their chronological date of surgery to evaluate how the learning curve affected screw placement outcomes. RESULTS: Total 80 patients were included; 73 (91%) had complete data and postoperative CT imaging that could help assess that placement of 352 thoracolumbar pedicle screws. The rate of clinically acceptable screw placement was high (96.6%, 95.4%, 95.6%, and 90.7%, in groups 1 to 4, respectively, p=0.314) over time. The median time per screw was 7.0 minutes (6.5, 7.0, 6.0, and 6.0 minutes in groups 1 to 4, respectively, p=0.605). Intraoperative revision occurred in only 1 of the 352 screws (0.3%). CONCLUSIONS: We found that robot-assisted screw placement had high accuracy, low placement time, low fluoroscopy time, and a low complication rate. However, there were no significant differences in these parameters at the initial experience and the practiced, experience placement (after approximately 1 year), indicating that robot-assisted pedicle screw placement has a very short (almost no) learning curve.

The role and safety of the sitting position in instrumented cervical surgery.

Placing patients who are undergoing neurosurgical procedures to the cervical spine in the sitting position offers significant advantages. These must be counterbalanced against the risk of venous and paradoxical air embolism. This study addresses the role and safety of the sitting position for instrumented cervical surgery. Twenty-five consecutive patients who underwent instrumented cervical surgery in the sitting position were recruited via retrospective analysis. Complications arising from the surgical procedure - specifically venous air embolism - were recorded, as well as pre- and post-operative haemoglobin levels. The incidence of venous air embolism was 0% (97.5% one-sided confidence interval: 0-13.7%). However, five other complications occurred (incidence rate of 20% with a 95% confidence interval of 6.8-40.7%). With appropriate precautions, screening and specific indications, the sitting position can be safely used in more complex instrumented cervical surgery.

Primary angiitis of the central nervous system presenting as a mass lesion.

We report a 51-year-old Asian man with primary angiitis of the central nervous system (PACNS) with atypical presentation as a mass lesion. PACNS is an uncommon condition causing inflammation and destruction of the blood vessels of the central nervous system. The aetiology is unclear and multiple mechanisms have been proposed. Its incidence is estimated at 2.4 per million per year, affecting patients of all ages (median 50 years) and more commonly Caucasian men. In Australia, 12 patients fulfilled the diagnostic criteria for PACNS between 1998 and 2009 at The Royal Melbourne Hospital, a university-affiliated tertiary referral centre. The accurate and timely diagnosis of PACNS is very challenging due to disease mimicry and the absence of specific serological tests. This patient illustrates additional diagnostic difficulty with his atypical PACNS presentation as a mass lesion.