Virtual-versus-Real Implantation of Flow Diverters: Clinical Potential and Influence of Vascular Geometry.

BACKGROUND AND PURPOSE: Intracranial stents have become extremely important in the endovascular management of complex intracranial aneurysms. Sizing and landing zone predictions are still very challenging steps in the procedure. Virtual stent deployment may help therapeutic planning, device choice, and hemodynamic simulations. We aimed to assess the predictability of our recently developed virtual deployment model by comparing in vivo and virtual stents implanted in a consecutive series of patients presenting with intracranial aneurysms. MATERIALS AND METHODS: Virtual stents were implanted in patient-specific geometries of intracranial aneurysms treated with the Pipeline Embolization Device. The length and cross-section of virtual and real stents measured with conebeam CT were compared. The influence of vessel geometry modifications occurring during the intervention was analyzed. RESULTS: The virtual deployment based on pre- and poststent implantation 3D rotational angiography overestimated (underestimated) the device length by 13% ± 11% (-9% ± 5%). These differences were highly correlated (R2 = 0.67) with the virtual-versus-real stent radius differences of -6% ± 7% (5% ± 4%) for predictions based on pre- and poststent implantation 3D rotational angiography. These mismatches were due principally to implantation concerns and vessel-shape modifications. CONCLUSIONS: The recently proposed geometric model was shown to predict accurately the deployment of Pipeline Embolization Devices when the stent radius was well-assessed. However, unpredictable delivery manipulations and variations of vessel geometry occurring during the intervention might impact the stent implantation.

MRI-Guided Percutaneous Biopsy of Mediastinal Masses Using a Large Bore Magnet: Technical Feasibility.

OBJECTIVE: To evaluate the diagnostic accuracy and safety of magnetic resonance imaging (MRI)-guided percutaneous biopsy of mediastinal masses performed using a wide-bore high-field scanner. MATERIALS AND METHODS: This is a retrospective study of 16 consecutive patients (8 male, 8 female; mean age 74 years) who underwent MRI-guided core needle biopsy of a mediastinal mass between February 2010 and January 2014. Size and location of lesion, approach taken, time for needle placement, overall duration of procedure, and post-procedural complications were evaluated. Technical success rates and correlation with surgical pathology (where available) were assessed. RESULTS: Target lesions were located in the anterior (n = 13), middle (n = 2), and posterior mediastinum (n = 1), respectively. Mean size was 7.2 cm (range 3.6-11 cm). Average time for needle placement was 9.4 min (range 3-18 min); average duration of entire procedure was 42 min (range 27-62 min). 2-5 core samples were obtained from each lesion (mean 2.6). Technical success rate was 100%, with specimens successfully obtained in all 16 patients. There were no immediate complications. Histopathology revealed malignancy in 12 cases (4 of which were surgically confirmed), benign lesions in 3 cases (1 of which was false negative following surgical resection), and one inconclusive specimen (treated as inaccurate since repeat CT-guided biopsy demonstrated thymic hyperplasia). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy in our study were 92.3, 100, 100, 66.7, and 87.5%, respectively. CONCLUSION: MRI-guided mediastinal biopsy is a safe procedure with high diagnostic accuracy, which may offer a non-ionizing alternative to CT guidance.

The reduction of coma time in lipophilic drug overdose using castor oil.

A clinical trial of castor oil in overdoses of lipophilic drugs gave a strong clinical impression that it was effective in speeding up recovery. Therefore, animal experiments were undertaken to confirm that castor oil acts as a ligand in Ethchlorvynol poisoning and that its use reduces coma time. Serial serum levels of Ethchlorvynol were obtained from dogs given Ethchlorvynol 150 mg/kg alone, and the same dose dissolved in castor oil 15 ml/kg in a crossover fashion. The result was a reduction of peak serum levels and of the half-life of the drug when the castor oil solution was used. In order to mimic the clinical situation more closely, a further crossover study was undertaken using Ethchlorvynol 300 mg/kg alone and the same dose followed by castor oil 15 ml/kg repeated q12h. This showed no delay in reaching peak serum concentration and no reduction of peak levels. However, it did show a 31 per cent reduction in the half-life of the drug. This change is statistically significant, and supports the continued use of castor oil in lipophilic drug overdose.