Direct Target Point Determination for Stereotactic Brain Operations from CT Data and the Calculation of Setting Parameters for Polar-Coordinate Stereotactic Devices

1982 ◽  
Vol 45 (4-5) ◽  
pp. 387-395 ◽  
Author(s):  
W. Birg ◽  
F. Mundinger
Keyword(s):  
Target Point ◽  
Polar Coordinate ◽  
Point Determination ◽  
Direct Target ◽  
Brain Operations ◽  
Ct Data ◽  
Setting Parameters

Relevance of Image Fusion for Target Point Determination in Functional Neurosurgery

2002 ◽  
Vol 144 (5) ◽  
pp. 445-451 ◽  
Author(s):  
F. Duffner ◽  
H. Schiffbauer ◽  
S. Breit ◽  
S. Friese ◽  
D. Freudenstein
Keyword(s):  
Image Fusion ◽  
Target Point ◽  
Functional Neurosurgery ◽  
Point Determination

Blinded re-analysis of CT-data with HeartNavigator®: Improved TAVI planning versus TEE and CT alone

2013 ◽  
Vol 61 (S 01) ◽  
Author(s):  
C Schmidtke ◽  
D Richardt ◽  
M Strauch ◽  
J Barkhausen ◽  
HH Sievers ◽  
...  
Keyword(s):  
Ct Data

Effect of CT-based attenuation correction on uptake ratios in skeletal SPECT

2007 ◽  
Vol 46 (01) ◽  
pp. 38-42 ◽  
Author(s):  
V. Schulz ◽  
I. Nickel ◽  
A. Nömayr ◽  
A. H. Vija ◽  
C. Hocke ◽  
...  
Keyword(s):  
Vertebral Body ◽  
Facet Joint ◽  
One Dimension ◽  
Patient Specific ◽  
Data Sets ◽  
Facet Joints ◽  
Lumbar Vertebral Body ◽  
Ct System ◽  
Ct Data ◽  
Attenuation Corrected

SummaryThe aim of this study was to determine the clinical relevance of compensating SPECT data for patient specific attenuation by the use of CT data simultaneously acquired with SPECT/CT when analyzing the skeletal uptake of polyphosphonates (DPD). Furthermore, the influence of misregistration between SPECT and CT data on uptake ratios was investigated. Methods: Thirty-six data sets from bone SPECTs performed on a hybrid SPECT/CT system were retrospectively analyzed. Using regions of interest (ROIs), raw counts were determined in the fifth lumbar vertebral body, its facet joints, both anterior iliacal spinae, and of the whole transversal slice. ROI measurements were performed in uncorrected (NAC) and attenuation-corrected (AC) images. Furthermore, the ROI measurements were also performed in AC scans in which SPECT and CT images had been misaligned by 1 cm in one dimension beforehand (ACX, ACY, ACZ). Results: After AC, DPD uptake ratios differed significantly from the NAC values in all regions studied ranging from 32% for the left facet joint to 39% for the vertebral body. AC using misaligned pairs of patient data sets led to a significant change of whole-slice uptake ratios whose differences ranged from 3,5 to 25%. For ACX, the average left-to-right ratio of the facet joints was by 8% and for the superior iliacal spines by 31% lower than the values determined for the matched images (p <0.05). Conclusions: AC significantly affects DPD uptake ratios. Furthermore, misalignment between SPECT and CT may introduce significant errors in quantification, potentially also affecting leftto- right ratios. Therefore, at clinical evaluation of attenuation- corrected scans special attention should be given to possible misalignments between SPECT and CT.

Preoperative assessment of treatment planning on minimization of micro-movement during healing period of immediate-loaded implants using X-ray CT data-based simulation

2010 ◽  
pp. 110220121911010
Author(s):  
KATSUHIKO KIMURA ◽  
Yasumasa Fukase ◽  
Michiko Makino ◽  
Chihiro Masaki ◽  
Tetsuji Nakamoto ◽  
...  
Keyword(s):  
Treatment Planning ◽  
Preoperative Assessment ◽  
X Ray ◽  
Healing Period ◽  
Ct Data

Computerized Modeling Based on Spiral CT Data for Noninvasive Determination of Aortic Stent-Graft Length

2002 ◽  
Vol 9 (4) ◽  
pp. 520-528 ◽  
Author(s):  
Albert Rott ◽  
Thomas Boehm ◽  
Joachim Söldner ◽  
Jürgen R. Reichenbach ◽  
Jürgen Heyne ◽  
...  
Keyword(s):  
Stent Graft ◽  
Spiral Ct ◽  
Aortic Stent Graft ◽  
Ct Data ◽  
Graft Length

Accuracy of robot-assisted versus optical frameless navigated stereoelectroencephalography electrode placement in children

2019 ◽  
Vol 23 (3) ◽  
pp. 297-302 ◽  
Author(s):  
Julia D. Sharma ◽  
Kiran K. Seunarine ◽  
Muhammad Zubair Tahir ◽  
Martin M. Tisdall
Keyword(s):  
Soft Tissue ◽  
Entry Point ◽  
Electrode Placement ◽  
Target Point ◽  
Localization Error ◽  
Bone Thickness ◽  
Tissue Thickness ◽  
Robot Assisted ◽  
Soft Tissue Thickness ◽  
Safety Margins

OBJECTIVEThe aim of this study was to compare the accuracy of optical frameless neuronavigation (ON) and robot-assisted (RA) stereoelectroencephalography (SEEG) electrode placement in children, and to identify factors that might increase the risk of misplacement.METHODSThe authors undertook a retrospective review of all children who underwent SEEG at their institution. Twenty children were identified who underwent stereotactic placement of a total of 218 electrodes. Six procedures were performed using ON and 14 were placed using a robotic assistant. Placement error was calculated at cortical entry and at the target by calculating the Euclidean distance between the electrode and the planned cortical entry and target points. The Mann-Whitney U-test was used to compare the results for ON and RA placement accuracy. For each electrode placed using robotic assistance, extracranial soft-tissue thickness, bone thickness, and intracranial length were measured. Entry angle of electrode to bone was calculated using stereotactic coordinates. A stepwise linear regression model was used to test for variables that significantly influenced placement error.RESULTSBetween 8 and 17 electrodes (median 10 electrodes) were placed per patient. Median target point localization error was 4.5 mm (interquartile range [IQR] 2.8–6.1 mm) for ON and 1.07 mm (IQR 0.71–1.59) for RA placement. Median entry point localization error was 5.5 mm (IQR 4.0–6.4) for ON and 0.71 mm (IQR 0.47–1.03) for RA placement. The difference in accuracy between Stealth-guided (ON) and RA placement was highly significant for both cortical entry point and target (p < 0.0001 for both). Increased soft-tissue thickness and intracranial length reduced accuracy at the target. Increased soft-tissue thickness, bone thickness, and younger age reduced accuracy at entry. There were no complications.CONCLUSIONSRA stereotactic electrode placement is highly accurate and is significantly more accurate than ON. Larger safety margins away from vascular structures should be used when placing deep electrodes in young children and for trajectories that pass through thicker soft tissues such as the temporal region.

Thalamic lesions produced by gamma thalamotomy for movement disorders

2002 ◽  
Vol 97 ◽  
pp. 600-606 ◽  
Author(s):  
Chihiro Ohye ◽  
Tohru Shibazaki ◽  
Jie Zhang ◽  
Yoshitaka Andou
Keyword(s):  
Mr Imaging ◽  
Involuntary Movement ◽  
Gamma Knife Radiosurgery ◽  
Target Point ◽  
High Signal ◽  
Thalamic Lesion ◽  
Content Type ◽  
Stereotactic Thalamotomy ◽  
Thalamic Lesions ◽  
Fine Print

Object. The treatment of Parkinson disease and other kinds of involuntary movement by gamma knife radiosurgery (GKS) is presented. This is an extension of previous work. The clinical course and thalamic lesions were the main factors examined. Methods. Seventeen new cases were added to the previously reported 36 cases. The course and results for the whole series of 53 patients were examined. Treatment was undertaken using a single 4-mm collimator shot to deliver 130 Gy to the target. The target was determined in the previously treated patients by using classic methods involved in conventional stereotactic thalamotomy with microrecording. More recently, target localization has been performed by relating the target point to the total length of the thalamus. Points may then be defined as percentages of that length measured from the anterior pole. Targets can then be determined in relationship to the appropriate percentage. Thirty-five patients have been followed for more than 2 years and the longest follow up was 8 years. Two kinds of thalamic lesion were seen after GKS. Volumetric analysis on MR imaging revealed that the larger lesion was 400 to 500 mm3 at the beginning and gradually decreased in size. The smaller lesion occupied approximately 200 mm3 and also shrank over several months. Eighty percent of the treated cases showed good results and no significant complications, with the tremor subsiding at 1 year (Type 1). Several cases deviated from this standard course in four different ways (Types 2–5). If tremor persisted, conventional stereotactic thalamotomy with microrecording was performed. During such operations, normal neuronal activity was recorded from the region adjacent to the GKS thalamotomy target. This was the region showing a high signal on MR imaging. The activity patterns included the rhythmical grouped discharge of tremor rhythm. Conclusions. Gamma thalamotomy for functional disorders is still under development, but because the results with careful target planning are satisfactory, there are grounds for increasing optimism.

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