A multi-centre retrospective study indicates that the fast RFA solver is capable of providing the IR with the predicted lesion in the short time period before the intervention begins when the patient has been clinically prepared for the treatment.

Aims/background-Recurrent peripheral retinal detachments may occur in eyes treated with vitrectomy and silicone oil for retinal detachments complicated by proliferative vitreoretinopathy (PVR). The aim of this study was to assess whether laser photocoagulation could be used in the presence of silicone oil to confine and stabilise recurrent PVR related peripheral retinal detachments enabling the timely removal of the oil. Methods-10 patients with recurrent peripheral retinal detachments after vitrectomy and silicone oil insertion were treated with posturing and subsequent focal argon laser to circumscribe the area of recurrent detachment. Results-This technique alone was suYcient to limit the area of retinal detachment in seven of the cases. The remaining three cases required relieving retinotomies because of increasing retinal detachment despite the laser. In all 10 cases the silicone oil was later removed without progression of the detached areas. Conclusion-Silicone assisted argon laser 'confinement' can be eVective in stabilising eyes with peripheral retinal detachments allowing the subsequent removal of silicone oil. (Br J Ophthalmol 1997;81:765-770) Proliferative vitreoretinopathy (PVR) is the commonest cause of retinal detachment surgery failure.

Purpose To validate a simulation environment for virtual planning of percutaneous cryoablation of renal tumors. Materials and Methods Prospectively collected data from 19 MR-guided procedures were used for validation of the simulation model. Volumetric overlap of the simulated ablation zone volume (Σ) and the segmented ablation zone volume (S; assessed on 1-month follow-up scan) was quantified. Validation metrics were DICE Similarity Coefficient (DSC; the ratio between twice the overlapping volume of both ablation zones divided by the sum of both ablation zone volumes), target overlap (the ratio between the overlapping volume of both ablation zones to the volume of S; low ratio means S is underestimated), and positive predictive value (the ratio between the overlapping volume of both ablation zones to the volume of Σ; low ratio means S is overestimated). Values were between 0 (no alignment) and 1 (perfect alignment), a value > 0.7 is considered good. Results Mean volumes of S and Σ were 14.8 cm3 (± 9.9) and 26.7 cm3 (± 15.0), respectively. Mean DSC value was 0.63 (± 0.2), and ≥ 0.7 in 9 cases (47%). Mean target overlap and positive predictive value were 0.88 (± 0.11) and 0.53 (± 0.24), respectively. In 17 cases (89%), target overlap was ≥ 0.7; positive predictive value was ≥ 0.7 in 4 cases (21%) and < 0.6 in 13 cases (68%). This indicates S is overestimated in the majority of cases. Conclusion The validation results showed a tendency of the simulation model to overestimate the ablation effect. Model adjustments are necessary to make it suitable for clinical use.

The web-based Go-Smart environment is a scalable system that allows the prediction of minimally invasive cancer treatment. Interventional radiologists create a patient-specific 3D model by semi-automatic segmentation and registration of pre-interventional CT (Computed Tomography) and/or MRI (Magnetic Resonance Imaging) images in a 2D/3D browser environment. This model is used to compare patient-specific treatment plans and device performance via built-in simulation tools. Go-Smart includes evaluation techniques for comparing simulated treatment with real ablation lesions segmented from follow-up scans. The framework is highly extensible, allowing manufacturers and researchers to incorporate new ablation devices, mathematical models and physical parameters

SummaryA case of atypical headache presenting following otherwise unremarkable epidural analgesia in labour is presented. Although there was no suggestion of accidental dural puncture during insertion of the epidural catheter, and despite the unusual features of the headache and complicated case history, an epidural blood patch was performed 13 weeks post-partum, with improvement of the patient's symptoms. A repeat epidural blood patch 2 weeks later completely resolved her headache.