what if you cannot see the target two case studies of atlas to patient registration in trigeminal neuralgia radiosurgery

Introduction: Medically resistant trigeminal neuralgia (TN) is a wellsuited pathology to be treated by radiosurgery (RS). A significant percentage (60%-70%) of patients is expected to benefit from the RS treatment. Imaging is crucial to identify the target, though unfortunately in some cases the trigeminal nerve could not be visible even in high field magnetic resonance images (MRI). The aim of this work is to develop and relatively validate a method for the atlas-based identification of the target in those cases where the trigeminal nerve is not visible. Material Methods: The proposed method is based on the modification of a previously published approach for functional RS, adapted to the TN. A high resolution, high contrast volumetric T1-MRI atlas was nonrigidly registered to patient T1-MRI. Two patients scanned with a 3T T1-weighted-MRI and trigeminal nerve specific MR (Constructive Interference in Steady State – CISS) sequences were considered in this study. In both cases, the right-sided trigeminal nerve was not visible, while it was the contralateral nerve. For one patient, we simulated a potential radiosurgical treatment plan. The atlas-based localization accuracy of the trigeminal nerve was validated in a relative way evaluating the nearby structure continuity and the contralateral nerve localization

Ten daily fractions for partial breast irradiation. Long-term results of a prospective phase II trial.

Partial breast irradiation (PBI) is an effective adjuvant treatment after breast conservative surgery for selected early-stage breast cancer patients. However, the best fractionation scheme is not well defined. Hereby, we report the 5-year clinical outcome and toxicity of a phase II prospective study of a novel regimen to deliver PBI, which consists in 40 Gy delivered in 10 daily fractions. Patients with early-stage (pT1-pT2, pN0-pN1a, M0) invasive breast cancer were enrolled after conservative surgery. The minimum age at diagnosis was 60 years old. PBI was delivered with 3D-conformal radiotherapy technique with a total dose of 40 Gy, fractionated in 10 daily fractions (4 Gy/fraction). Eighty patients were enrolled. The median follow-up was 67 months. Five-year local control (LC), disease-free survival (DFS), and overall survival (OS) were 95%, 91%, and 96%, respectively. Grade I and II subcutaneous fibrosis were documented in 23% and 5% of cases. No grade III late toxicity was observed. PBI delivered in 40 Gy in 10 daily fractions provided good clinical results and was a valid radiotherapy option for early-stage breast cancer patients

Confirmation of functional zones within the human subthalamic nucleus: Patterns of connectivity and sub-parcellation using diffusion weighted imaging

The subthalamic nucleus (STN) is a small, glutamatergic nucleus situated in the diencephalon. A critical component of normal motor function, it has become a key target for deep brain stimulation in the treatment of Parkinson's disease. Animal studies have demonstrated the existence of three functional sub-zones but these have never been shown conclusively in humans. In this work, a data driven method with diffusion weighted imaging demonstrated that three distinct clusters exist within the human STN based on brain connectivity profiles. The STN was successfully sub-parcellated into these regions, demonstrating good correspondence with that described in the animal literature. The local connectivity of each sub-region supported the hypothesis of bilateral limbic, associative and motor regions occupying the anterior, mid and posterior portions of the nucleus respectively. This study is the first to achieve in-vivo, non-invasive anatomical parcellation of the human STN into three anatomical zones within normal diagnostic scan times, which has important future implications for deep brain stimulation surgery

[Photograph 2012.201.B1436.0494]

Photograph used for a story in the Oklahoma Times newspaper. Caption: "After artist's touch-up adds a splash of color, underpass loses its school-kid letterings.

Open Access Case Report What if You Cannot See the Target? Two Case Studies of Atlas-to-Patient Registration in Trigeminal Neuralgia Radiosurgery

Abstract Introduction: Medically resistant trigeminal neuralgia (TN) is a well

Open Access Case Report What if You Cannot See the Target? Two Case Studies of Atlas-to-Patient Registration in Trigeminal Neuralgia Radiosurgery

Abstract Introduction: Medically resistant trigeminal neuralgia (TN) is a well

Angiography for Radiosurgery and Radiation Therapy

IMAGE-GUIDED THERAPEUTIC PROCEDURES - Angiography for Radiosurgery and Radiation Therap

Atlas Based Identification Of Targets For Functional Radiosurgery

Functional disorders of the brain, such as Parkinson's disease, dystonia, epilepsy, and neuropathic pain, may exhibit poor response to medical therapy. In such cases, surgical intervention may become necessary. Modern surgical approaches to such disorders include radio-frequency lesioning and deep brain stimulation (DBS). The subthalamic nucleus (STN) is one of the most useful stereotactic targets available: STN DBS is known to induce substantial improvement in patients with end-stage Parkinson's disease. Other targets include the Globus Pallidus pars interna (GPi) for dystonia and Parkinson's disease, and the centromedian nucleus of the thalamus (CMN) for neuropathic pain. Radiosurgery is an attractive noninvasive alternative to treat some functional brain disorders. The main technical limitation to radiosurgery is that the target can be selected only on the basis of magnetic resonance anatomy without electrophysiological confirmation. The aim of this work is to provide a method for the correct atlas-based identification of the target to be used in functional neurosurgery treatment planning. The coordinates of STN, CMN, and GPi were identified in the Talairach and Tournoux atlas and transformed to the corresponding regions of the Montreal Neurological Institute (MNI) electronic atlas. Binary masks describing the target nuclei were created. The MNI electronic atlas was deformed onto the patient magnetic resonance imaging-T1 scan by applying an affine transformation followed by a local nonrigid registration. The first transformation was based on normalized cross correlation and the second on optimization of a two-part objective function consisting of similarity criteria and weighted regularization. The obtained deformation field was then applied to the target masks. The minimum distance between the surface of an implanted electrode and the surface of the deformed mask was calculated. The validation of the method consisted of comparing the electrode-mask distance to the clinical outcome of the treatments in ten cases of bilateral DBS implants. Electrode placement may have an effect within a radius of stimulation equal to 2 rum, therefore the registration process is considered successful if error is less than 2 rum. The registrations of the MNI atlas onto the patient space succeeded in all cases. The comparison of the distance to the clinical outcome revealed good agreement: where the distance was high (at least in one implant), the clinical outcome was poor; where there was a close correlation between the structures, clinical outcome revealed an improvement of the pathological condition. In conclusion, the proposed method seems to provide a useful tool for the identification of the target nuclei for functional radiosurgery. Also, the method is applicable to other types of functional treatment. (C) 2006 American Association of Physicists in Medicine

Atlas-based identification of targets for functional radiosurgery

none6noneSTANCANELLO J; ROMANELLI P. MODUGNO N; P. CERVERI; FERRIGNO G; UGGERI F; CANTORE GStancanello, J; ROMANELLI P., MODUGNO N; Cerveri, Pietro; Ferrigno, Giancarlo; Uggeri, F; Cantore, G