Avoiding the Intercostal Arteries in Percutaneous Thoracic Interventions.

The purpose of this study was to define relevant intercostal artery (ICA) anatomy potentially impacting the safety of thoracic percutaneous interventional procedures. An ICA abutting the upper rib and running in the subcostal groove was defined as the lowest risk zone for interventions requiring a supracostal needle puncture. A theoretical high-risk zone was defined by the ICA coursing in the lower half of the intercostal space (ICS), and a theoretical moderate-risk zone was defined by the ICA coursing below the subcostal groove but in the upper half of the ICS. Arterial phase computed tomography data from 250 patients were analyzed, revealing demographic variability, with high-risk zones extending more laterally with advancing age and with more cranial ribs. Overall, within the 97.5th percentile, an ICS puncture >7-cm lateral to the spinous process incurs moderate risk and >10-cm lateral incurs the lowest risk

T2-relaxometry predicts outcome of DBS in idiopathic Parkinson's disease.

INTRODUCTION Deep brain stimulation (DBS) nowadays is a well-established treatment of motor symptoms in Parkinson's disease. The subthalamic nucleus (STN) is a common target for DBS, because motor improvements have been shown to be superior to best medical therapy, if DBS electrodes have been appropriately positioned. DBS target identification can be assisted by MRI beyond structural imaging by spatially resolved measurement of T2-relaxation times (T2r). AIM We pose the question, whether T2r of the STN is linked to the severity of the disease and whether outcome of DBS may be correlated to an asymmetric manifestation of the disease. Further, we investigated if abnormal T2r in the STN may be predictive for outcome of DBS. METHODS Twelve patients underwent preoperative MR imaging including a multi echo relaxometry sequence (3 Tesla, Siemens Medical Systems, Erlangen, Germany) ahead of DBS. T2r were determined for STN, substantia nigra (SN), red nucleus (RN) and centrum semiovale (CSO). Unified Parkinson's disease Rating Scale (UPDRS) scores were tested before and after DBS. Patients' T2r and deduced values representing left-right asymmetry of measurements were correlated with UPDRS scores and measures for outcome of DBS. Furthermore, patients' T2r were compared with T2r measurements in 12 healthy controls (HC). RESULTS Patients' T2r for SN (mean 45.4 ms ± 4.4 ms) and STN (mean 56.4 ms ± 3.8 ms) were significantly shorter than T2r in HCs for SN (mean 60.7 ± 4.6) and STN (mean 66.1 ms ± 4.0 ms). While no mean T2r asymmetry was found in the SN, patients' mean T2r for STN showed a weakened left-right correlation (Pearson correlation coefficient 0.19 versus 0.72 in HC) indicating asymmetric degeneration. T2r asymmetry was not linked to the more severely affected hemisphere. The respective lower T2r within the left or right target region was significantly correlated to the outcome in terms of UPDRS III improvement in "off" state (Pearson correlation 0.82 corresponding to p ≪ 0.01). Patients with T2r of STN lower than 50 ms showed no response to DBS in the UPDRS. The maximum T2r for SN correlated to the improvement between UPDRS "off" minus and "on" (Dopamine response) but failed to predict DBS outcome. CONCLUSIONS The lower boundaries of T2r in the STN predict motor outcome in DBS. T2r asymmetry in the STN is not associated with increased clinical symptoms, but with response to therapy. Thus, patients with very low T2r may be inappropriate candidates for DBS

Metabolic pathway and distribution of superparamagnetic iron oxide nanoparticles: in vivo study

Experimental tissue fusion benefits from the selective heating of superparamagnetic iron oxide nanoparticles (SPIONs) under high frequency irradiation. However, the metabolic pathways of SPIONs for tissue fusion remain unknown. Hence, the goal of this in vivo study was to analyze the distribution of SPIONs in different organs by means of magnetic resonance imaging (MRI) and histological analysis after a SPION-containing patch implantation

Validation of targeting the ventrointermediate thalamic nucleus using Q-ball calculation in deep brain stimulation for tremor

Objective: Identification of the ventrointermediate thalamic nucleus (Vim) in modern 3T high-field MRI for image-based targeting in deep brain stimulation (DBS) is still challenging. To evaluate the usefulness and reliability of analyzing the connectivity with the cerebellum using Q-ball-calculation we performed a retrospective analysis. Method: 5 patients who underwent bilateral implantation of electrodes in the Vim for treatment of Essential Tremor between 2011 and 2012 received additional preoperative Q-ball imaging. Targeting was performed according to atlas coordinates and standard MRI. Additionally we performed a retrospective identification of the Vim by analyzing the connectivity of the thalamus with the dentate nucleus. The exact position of the active stimulation contact in the postoperative CT was correlated with the Vim as it was identified by Q-ball calculation. Results: Localization of the Vim by analysis of the connectivity between thalamus and cerebellum was successful in all 5 patients on both sides. The average position of the active contacts was 14.6 mm (SD 1.24) lateral, 5.37 mm (SD 0.094 posterior and 2.21 mm (SD 0.69) cranial of MC. The cranial portion of the dentato-rubro-thalamic tract was localized an average of 3.38 mm (SD 1.57) lateral and 1.5 mm (SD 1.22) posterior of the active contact. Conclusions: Connectivity analysis by Q-ball calculation provided direct visualization of the Vim in all cases. Our preliminary results suggest, that the target determined by connectivity analysis is valid and could possibly be used in addition to or even instead of atlas based targeting. Larger prospective calculations are needed to determine the robustness of this method in providing refined information useful for neurosurgical treatment of tremor

Bilateral pallidal stimulation improves cervical dystonia for more than a decade.

INTRODUCTION Deep brain stimulation (DBS) is an effective treatment in medically resistant cervical dystonia (CD) with a documented therapeutic effect. Long term outcome beyond a decade, however, has not been studied systematically. METHODS To investigate the impact of pallidal DBS beyond 10 years in CD we followed a series of five consecutive patients with severe medication-resistant CD. Severity of head and neck deviation, disability, and pain related to dystonia were assessed by the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) in the frame of a prospective study. The primary endpoint of this study was a change in the TWSTRS total score. Secondary endpoints were changes in the subscores of the TWSTRS. RESULTS The mean follow-up time was 11.5 years (range 10-12.8). Comparing baseline and the last follow-up, CD improved by 53% on the total TWSTRS score, by 54.1% on the severity score, and by 70.1% on the disability score, while pain did not improve significantly. Improvement was stable over time. Patients with a tonic pattern of CD responded less to DBS than patients with a phasic pattern. DBS had no significant effect on mood and cognition. Two patients underwent electrode revisions. One patient had an infection of the proximal cable two years after surgery. CONCLUSIONS Chronic bilateral pallidal stimulation improves severity of dystonia and disability over more than a decade in treatment resistant CD. Results may vary among individual patients

T2-relaxometry predicts outcome of DBS in idiopathic Parkinson's disease

Introduction: Deep brain stimulation (DBS) nowadays is a well-established treatment of motor symptoms in Parkinson's disease. The subthalamic nucleus (STN) is a common target for DBS, because motor improvements have been shown to be superior to best medical therapy, if DBS electrodes have been appropriately positioned. DBS target identification can be assisted by MRI beyond structural imaging by spatially resolved measurement of T2-relaxation times (T2r). Aim: We pose the question, whether T2r of the STN is linked to the severity of the disease and whether outcome of DBS may be correlated to an asymmetric manifestation of the disease. Further, we investigated if abnormal T2r in the STN may be predictive for outcome of DBS. Methods: Twelve patients underwent preoperative MR imaging including a multi echo relaxometry sequence (3 Tesla, Siemens Medical Systems, Erlangen, Germany) ahead of DBS. T2r were determined for STN, substantia nigra (SN), red nucleus (RN) and centrum semiovale (CSO). Unified Parkinson's disease Rating Scale (UPDRS) scores were tested before and after DBS. Patients' T2r and deduced values representing left-right asymmetry of measurements were correlated with UPDRS scores and measures for outcome of DBS. Furthermore, patients' T2r were compared with T2r measurements in 12 healthy controls (HC). Results: Patients' T2r for SN (mean 45.4 ms ± 4.4 ms) and STN (mean 56.4 ms ± 3.8 ms) were significantly shorter than T2r in HCs for SN (mean 60.7 ± 4.6) and STN (mean 66.1 ms ± 4.0 ms). While no mean T2r asymmetry was found in the SN, patients' mean T2r for STN showed a weakened left-right correlation (Pearson correlation coefficient 0.19 versus 0.72 in HC) indicating asymmetric degeneration. T2r asymmetry was not linked to the more severely affected hemisphere. The respective lower T2r within the left or right target region was significantly correlated to the outcome in terms of UPDRS III improvement in “off” state (Pearson correlation 0.82 corresponding to p ≪ 0.01). Patients with T2r of STN lower than 50 ms showed no response to DBS in the UPDRS. The maximum T2r for SN correlated to the improvement between UPDRS “off” minus and “on” (Dopamine response) but failed to predict DBS outcome. Conclusions: The lower boundaries of T2r in the STN predict motor outcome in DBS. T2r asymmetry in the STN is not associated with increased clinical symptoms, but with response to therapy. Thus, patients with very low T2r may be inappropriate candidates for DBS