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Publications

Publications by Nuno Feixa Rodrigues

2013

Kidney Targeting and Puncturing During Percutaneous Nephrolithotomy: Recent Advances and Future Perspectives

Authors
Rodrigues, PL; Rodrigues, NF; Fonseca, J; Lima, E; Vilaca, JL;

Publication
JOURNAL OF ENDOUROLOGY

Abstract
Background and Purpose: Precise needle puncture of the kidney is a challenging and essential step for successful percutaneous nephrolithotomy (PCNL). Many devices and surgical techniques have been developed to easily achieve suitable renal access. This article presents a critical review to address the methodologies and techniques for conducting kidney targeting and the puncture step during PCNL. Based on this study, research paths are also provided for PCNL procedure improvement. Methods: Most relevant works concerning PCNL puncture were identified by a search of Medline/PubMed, ISI Web of Science, and Scopus databases from 2007 to December 2012. Two authors independently reviewed the studies. Results: A total of 911 abstracts and 346 full-text articles were assessed and discussed; 52 were included in this review as a summary of the main contributions to kidney targeting and puncturing. Conclusions: Multiple paths and technologic advances have been proposed in the field of urology and minimally invasive surgery to improve PCNL puncture. The most relevant contributions, however, have been provided by the application of medical imaging guidance, new surgical tools, motion tracking systems, robotics, and image processing and computer graphics. Despite the multiple research paths for PCNL puncture guidance, no widely acceptable solution has yet been reached, and it remains an active and challenging research field. Future developments should focus on real-time methods, robust and accurate algorithms, and radiation free imaging techniques.

2013

Palco: A Multisensor Realtime 3D Cartoon Production System

Authors
Torrao, L; Queiros, SF; Teixeira, PM; Vilaca, JL; Rodrigues, NF;

Publication
2013 IEEE 2ND INTERNATIONAL CONFERENCE ON SERIOUS GAMES AND APPLICATIONS FOR HEALTH (SEGAH)

Abstract
This paper presents Palco, a prototype system specifically designed for the production of 3D cartoon animations. The system addresses the specific problems of producing cartoon animations, where the main objective is not to reproduce realistic movements, but rather animate cartoon characters with predefined and characteristic body movements and facial expressions. The techniques employed in Palco are simple and easy to use, not requiring any invasive or complicated motion capture system, as both body motion and facial expression of actors are captured simultaneously, using an infrared motion detection sensor, a regular camera and a pair of electronically instrumented gloves. The animation process is completely actor-driven, with the actor controlling the character movements, gestures, facial expression and voice, all in realtime. The actor controlled cartoonification of the captured facial and body motion is a key functionality of Palco, and one that makes it specifically suited for the production of cartoon animations.

2013

Variations of the soft tissue thicknesses external to the ribs in Pectus Excavatum patients

Authors
Rodrigues, PL; Direito Santos, B; Moreira, AHJ; Fonseca, JC; Pinho, ACM; Rodrigues, NF; Henriques Coelho, T; Correia Pinto, J; Vilaca, JL;

Publication
JOURNAL OF PEDIATRIC SURGERY

Abstract
Background: Surgical repair of pectus excavatum (PE) has become more popular due to improvements in the minimally invasive Nuss procedure. The pre-surgical assessment of PE patients requires Computerized Tomography (CT), as the malformation characteristics vary from patient to patient. Objective: This work aims to characterize soft tissue thickness (STT) external to the ribs among PE patients. It also presents a comparative analysis between the anterior chest wall surface before and after surgical correction. Methods: Through surrounding tissue segmentation in CT data, STT values were calculated at different lines along the thoracic wall, with a reference point in the intersection of coronal and median planes. The comparative analysis between the two 3D anterior chest surfaces sets a surgical correction influence area (SCIA) and a volume of interest (VOI) based on image processing algorithms, 3D surface algorithms, and registration methods. Results: There are always variations between left and right side STTs (2.54 +/- 2.05 mm and 2.95 +/- 2.97 mm for female and male patients, respectively). STTs are dependent on age, sex, and body mass index of each patient. On female patients, breast tissue induces additional errors in bar manual conception. The distances starting at the deformity's largest depression point at the SCIA are similar in all directions. Some diverging measures and outliers were found, being difficult to find similar characteristics between them, especially in asymmetric patients. Conclusion: The Nuss procedure metal bar must be modeled according to each patient's special characteristics. The studied relationships between STT and chest surface could represent a step forward to eliminate the CT scan from PE pre-surgical evaluation.

2014

Artificial neural networks for automatic modelling of the pectus excavatum corrective prosthesis

Authors
Rodrigues, PL; Moreire, AHJ; Rodrigues, NF; Pinho, ACM; Fonseca, JC; Correia Pinto, J; Vilaca, JL;

Publication
MEDICAL IMAGING 2014: COMPUTER-AIDED DIAGNOSIS

Abstract
Pectus excavatum is the most common deformity of the thorax and usually comprises Computed Tomography (CT) examination for pre-operative diagnosis. Aiming at the elimination of the high amounts of CT radiation exposure, this work presents a new methodology for the replacement of CT by a laser scanner (radiation-free) in the treatment of pectus excavatum using personally modeled prosthesis. The complete elimination of CT involves the determination of ribs external outline, at the maximum sternum depression point for prosthesis placement, based on chest wall skin surface information, acquired by a laser scanner. The developed solution resorts to artificial neural networks trained with data vectors from 165 patients. Scaled Conjugate Gradient, Levenberg-Marquardt, Resilient Back propagation and One Step Secant gradient learning algorithms were used. The training procedure was performed using the soft tissue thicknesses, determined using image processing techniques that automatically segment the skin and rib cage. The developed solution was then used to determine the ribs outline in data from 20 patient scanners. Tests revealed that ribs position can be estimated with an average error of about 6.82 +/- 5.7 mm for the left and right side of the patient. Such an error range is well below current prosthesis manual modeling (11.7 +/- 4.01 mm) even without CT imagiology, indicating a considerable step forward towards CT replacement by a 3D scanner for prosthesis personalization.

2013

Automatic modeling of an orthotic bracing for nonoperative correction of Pectus Carinatum

Authors
Vilaca, JL; Rodrigues, PL; Moreira, AHJ; Fonseca, JG; Pinho, ACM; Fonseca, JC; Rodrigues, N;

Publication
VISAPP 2013 - Proceedings of the International Conference on Computer Vision Theory and Applications

Abstract
Pectus Carinatum is a deformity of the chest wall, characterized by an anterior protrusion of the sternum, often corrected surgically due to cosmetic motivation. This work presents an alternative approach to the current open surgery option, proposing a novel technique based on a personalized orthosis. Two different processes for the orthosis' personalization are presented. One based on a 3D laser scan of the patient chest, followed by the reconstruction of the thoracic wall mesh using a radial basis function, and a second one, based on a computer tomography scan followed by a neighbouring cells algorithm. The axial position where the orthosis is to be located is automatically calculated using a Ray-Triangle intersection method, whose outcome is input to a pseudo Kochenek interpolating spline method to define the orthosis curvature. Results show that no significant differences exist between the patient chest physiognomy and the curvature angle and size of the orthosis, allowing a better cosmetic outcome and less initial discomfort.

2013

Assessment of 3D scanners for modeling pectus carinatum corrective bar

Authors
Moreira, AHJ; Fonseca, JG; Rodrigues, PL; Fonseca, JC; Pinho, ACM; Correia Pinto, J; Rodrigues, NF; Vilaca, JL;

Publication
VISAPP 2013 - Proceedings of the International Conference on Computer Vision Theory and Applications

Abstract
Pectus Carinatum (PC) is a chest deformity consisting on the anterior protrusion of the sternum and adjacent costal cartilages. Non-operative corrections, such as the orthotic compression brace, require previous information of the patient chest surface, to improve the overall brace fit. This paper focuses on the validation of the Kinect scanner for the modelling of an orthotic compression brace for the correction of Pectus Carinatum. To this extent, a phantom chest wall surface was acquired using two scanner systems - Kinect and Polhemus FastSCAN - and compared through CT. The results show a RMS error of 3.25mm between the CT data and the surface mesh from the Kinect sensor and 1.5mm from the FastSCAN sensor.

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