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- Black, David, et al.
(author)
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Auditory display for Fluorescence-guided open brain tumor surgery
- 2018
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In: International Journal of Computer Assisted Radiology and Surgery. - : Elsevier. - 1861-6410 .- 1861-6429. ; 13:1, s. 25-35
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Journal article (peer-reviewed)abstract
- PURPOSE:Protoporphyrin (PpIX) fluorescence allows discrimination of tumor and normal brain tissue during neurosurgery. A handheld fluorescence (HHF) probe can be used for spectroscopic measurement of 5-ALA-induced PpIX to enable objective detection compared to visual evaluation of fluorescence. However, current technology requires that the surgeon either views the measured values on a screen or employs an assistant to verbally relay the values. An auditory feedback system was developed and evaluated for communicating measured fluorescence intensity values directly to the surgeon.METHODS:The auditory display was programmed to map the values measured by the HHF probe to the playback of tones that represented three fluorescence intensity ranges and one error signal. Ten persons with no previous knowledge of the application took part in a laboratory evaluation. After a brief training period, participants performed measurements on a tray of 96 wells of liquid fluorescence phantom and verbally stated the perceived measurement values for each well. The latency and accuracy of the participants' verbal responses were recorded. The long-term memorization of sound function was evaluated in a second set of 10 participants 2-3 and 7-12 days after training.RESULTS:The participants identified the played tone accurately for 98% of measurements after training. The median response time to verbally identify the played tones was 2 pulses. No correlation was found between the latency and accuracy of the responses, and no significant correlation with the musical proficiency of the participants was observed on the function responses. Responses for the memory test were 100% accurate.CONCLUSION:The employed auditory display was shown to be intuitive, easy to learn and remember, fast to recognize, and accurate in providing users with measurements of fluorescence intensity or error signal. The results of this work establish a basis for implementing and further evaluating auditory displays in clinical scenarios involving fluorescence guidance and other areas for which categorized auditory display could be useful.
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| 2. |
- Brudfors, Mikael, et al.
(author)
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Towards real-time, tracker-less 3D ultrasound guidance for spine anaesthesia
- 2015
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In: International Journal of Computer Assisted Radiology and Surgery. - : Springer Science and Business Media LLC. - 1861-6410 .- 1861-6429. ; 10:6, s. 855-865
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Journal article (peer-reviewed)abstract
- Purpose: Epidural needle insertions and facet joint injections play an important role in spine anaesthesia. The main challenge of safe needle insertion is the deep location of the target, resulting in a narrow and small insertion channel close to sensitive anatomy. Recent approaches utilizing ultrasound (US) as a low-cost and widely available guiding modality are promising but have yet to become routinely used in clinical practice due to the difficulty in interpreting US images, their limited view of the internal anatomy of the spine, and/or inclusion of cost-intensive tracking hardware which impacts the clinical workflow. Methods: We propose a novel guidance system for spine anaesthesia. An efficient implementation allows us to continuously align and overlay a statistical model of the lumbar spine on the live 3D US stream without making use of additional tracking hardware. The system is evaluated in vivo on 12 volunteers. Results: The in vivo study showed that the anatomical features of the epidural space and the facet joints could be continuously located, at a volume rate of 0.5 Hz, within an accuracy of 3 and 7 mm, respectively. Conclusions: A novel guidance system for spine anaesthesia has been presented which augments a live 3D US stream with detailed anatomical information of the spine. Results from an in vivo study indicate that the proposed system has potential for assisting the physician in quickly finding the target structure and planning a safe insertion trajectory in the spine.
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| 3. |
- Forsberg, Daniel, et al.
(author)
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Quantitative analysis of the patellofemoral motion pattern using semi-automatic processing of 4D CT data
- 2016
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In: International Journal of Computer Assisted Radiology and Surgery. - : SPRINGER HEIDELBERG. - 1861-6410 .- 1861-6429. ; 11:9, s. 1731-1741
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Journal article (peer-reviewed)abstract
- To present a semi-automatic method with minimal user interaction for quantitative analysis of the patellofemoral motion pattern. 4D CT data capturing the patellofemoral motion pattern of a continuous flexion and extension were collected for five patients prone to patellar luxation both pre- and post-surgically. For the proposed method, an observer would place landmarks in a single 3D volume, which then are automatically propagated to the other volumes in a time sequence. From the landmarks in each volume, the measures patellar displacement, patellar tilt and angle between femur and tibia were computed. Evaluation of the observer variability showed the proposed semi-automatic method to be favorable over a fully manual counterpart, with an observer variability of approximately 1.5 for the angle between femur and tibia, 1.5 mm for the patellar displacement, and 4.0-5.0 for the patellar tilt. The proposed method showed that surgery reduced the patellar displacement and tilt at maximum extension with approximately 10-15 mm and 15-20 for three patients but with less evident differences for two of the patients. A semi-automatic method suitable for quantification of the patellofemoral motion pattern as captured by 4D CT data has been presented. Its observer variability is on par with that of other methods but with the distinct advantage to support continuous motions during the image acquisition.
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| 6. |
- Lundström, Claes, 1973-
(author)
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vPSNR : a visualization-aware image fidelity metric tailored for diagnostic imaging
- 2013
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In: International Journal of Computer Assisted Radiology and Surgery. - : Springer. - 1861-6410 .- 1861-6429. ; 8:3, s. 437-450
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Journal article (peer-reviewed)abstract
- Purpose Often, the large amounts of data generated in diagnosticimaging cause overload problems for IT systems andradiologists. This entails a need of effective use of data reductionbeyond lossless levels, which, in turn, underlines theneed to measure and control the image fidelity. Existingimage fidelity metrics, however, fail to fully support importantrequirements from a modern clinical context: supportfor high-dimensional data, visualization awareness, and independencefrom the original data.Methods We propose an image fidelity metric, called thevisual peak signal-to-noise ratio (vPSNR), fulfilling the threemain requirements. A series of image fidelity tests on CTdata sets is employed. The impact of visualization transform(grayscalewindow) on diagnostic quality of irreversiblycompressed data sets is evaluated through an observer-basedstudy. In addition, several tests were performed demonstratingthe benefits, limitations, and characteristics of vPSNR indifferent data reduction scenarios.Results The visualization transform has a significant impacton diagnostic quality, and the vPSNR is capable of representingthis effect. Moreover, the tests establish that the vPSNRis broadly applicable.Conclusions vPSNR fills a gap not served by existingimage fidelity metrics, relevant for the clinical context. WhilevPSNR alone cannot fulfill all image fidelity needs, it can bea useful complement in a wide range of scenarios.
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| 7. |
- Maria Marreiros, Filipe Miguel, et al.
(author)
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Custom implant design for large cranial defects
- 2016
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In: International Journal of Computer Assisted Radiology and Surgery. - : Springer Science and Business Media LLC. - 1861-6410 .- 1861-6429. ; 11:12, s. 2217-2230
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Journal article (peer-reviewed)abstract
- PurposeThe aim of this work was to introduce a Computer Aided Design (CAD)tool that enables the design of large skull defects (> 100cm2) implants. Functional and aesthetically correct custom implants are extremely important for patients with large cranial defects. For these cases pre-operative fabrication of implants is recommended to avoid problems of donor site morbidity, sufficiencyof donor material and quality. Finally, crafting the correct shape is a non-trivial task increasingly complicated by defect size.MethodsWe present a Computer Aided Design (CAD) tool to design such implants for the neurocranium. A combination of Geometric Morphometrics (GM) and Radial Basis Functions (RBF), namely Thin Plate Splines (TPS), allows semiautomatic implant generation. The method uses symmetry and the best fitting shape to estimate missing data directly within the radiologic volume data. In addition, this approach delivers correct implant fitting via a boundary fitting approach.ResultsThis method generates a smooth implant surface, free of sharp edges that follows the main contours of the boundary, enabling accurate implant placementin the defect site intraoperatively. The present approach is evaluated and compared to existing methods. A mean error of 89.29% (72.64% - 100%)missing landmarks with an error less or equal to 1 mm was obtained.ConclusionIn conclusion, the results show that our Computer Aided Design (CAD)tool can generate patient specific implants with high accuracy.
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| 9. |
- Nilsson, Johanna, et al.
(author)
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Evaluation of in-house, haptic assisted surgical planning for virtual reduction of complex mandibular fractures
- 2021
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In: International Journal of Computer Assisted Radiology and Surgery. - : Springer. - 1861-6410 .- 1861-6429. ; 16:6, s. 1059-1068
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Journal article (peer-reviewed)abstract
- The management of complex mandible fractures, i.e severely comminuted or fractures of edentulous/atrophic mandibles, can be challenging. This is due to the three-dimensional loss of bone, which limits the possibility for accurate anatomic reduction. Virtual surgery planning (VSP) can provide improved accuracy and shorter operating times, but is often not employed for trauma cases because of time constraints and complex user interfaces limited to two-dimensional interaction with three-dimensional data. In this study, we evaluate the accuracy, precision, and time efficiency of the Haptic Assisted Surgery Planning system (HASP), an in-house VSP system that supports stereo graphics, six degrees-of-freedom input and haptics, to improve the surgical planning. Three operators performed planning in HASP on Computed Tomography (CT) and Come Beam Computed Tomography (CBCT) images of a plastic skull model and on twelve retrospective cases with complex mandible fractures. The result shows an accuracy and reproducibility of less than 2mm when using HASP, with an average planning time of 15 minutes, including time for segmentation in the software BoneSplit. This study presents an in-house haptic assisted planning tool for cranio-maxillofacial surgery with high usability that can be used for preoperative planning and evaluation of complex mandible fractures.
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| 10. |
- Noh, Y., et al.
(author)
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WKA-1R robot-assisted quantitative assessment of airway management
- 2008
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In: International Journal of Computer Assisted Radiology and Surgery, 3(6): 543-550. - : Springer. - 1861-6410 .- 1861-6429. ; 3:6, s. 543-550
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Journal article (peer-reviewed)abstract
- ObjectThe emerging field of medical robotics aims tointroduce intelligent tools for physician support. The main challenges for developing efficient medical robotic training systems are simulating real-world conditions of the task and assuring training effectiveness. High anatomic fidelity has been achieved in current systems, but they are limited to provide merely subjective assessments of the training progress. We simulated airway intubation using a unique medical robot and developed objective performance criteria to assess task performance.Materials and methodsA patient simulation robot was designed to mimic real-world task conditions and provide objective assessments of training progress. The Waseda– Kyotokagaku Airway No. 1R (WKA-1R) includes a human patient model with embedded sensors. An evaluation function was developed for the WKA-1R to quantitatively assess task performance. The evaluation includes performance indices and coefficient weighting. The performance indices were defined based on experiments carried out with medical doctors and from information found in the medical literature. The performance indices are: intubation time, jaw opening, incisor teeth force, cuff pressure, tongue force and tube position. To determine the weighting of coefficients, we used discriminant analysis.ResultsExperiments were carried out with volunteers to determine the effectiveness of the WKA-1R to quantitatively evaluate their performance while performing airway management. We asked subjects from different levels of expertise (from anesthetists to unskilled) to perform the task. From the experimental results, we determined operator effectiveness using the proposed performance indices. We found a significant difference between the experimental groups by evaluating their performances using the proposed evaluation function (P < 0.05).ConclusionsThe WKA-1R robot was designed to quantitatively acquire information on the performances of trainees during intubation procedures. From the experimental results, we could objectively determine operator effectiveness while providing quantitative task assessments.
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