T Rodt

Publications of T Rodt

• Diffusion tensor imaging and tractography for assessment of renal allograft dysfunction-initial results.

  Authors: Katja Hueper, M Gutberlet, T Rodt, W Gwinner, F Lehner, F Wacker, M Galanski, D Hartung

  European radiology. 06/2011; 21(11):2427-33.

  To evaluate MR diffusion tensor imaging (DTI) as non-invasive diagnostic tool for detection of acute and chronic allograft dysfunction and changes of organ microstructure. 15 kidney transplantedTo evaluate MR diffusion tensor imaging (DTI) as non-invasive diagnostic tool for detection of acute and chronic allograft dysfunction and changes of organ microstructure. 15 kidney transplanted patients with allograft dysfunction and 14 healthy volunteers were examined using a fat-saturated echo-planar DTI-sequence at 1.5 T (6 diffusion directions, b = 0, 600 s/mm²). Mean apparent diffusion coefficient (ADC) and mean fractional anisotropy (FA) were calculated separately for the cortex and for the medulla and compared between healthy and transplanted kidneys. Furthermore, the correlation between diffusion parameters and estimated GFR was determined. The ADC in the cortex and in the medulla were lower in transplanted than in healthy kidneys (p < 0.01). Differences were more distinct for FA, especially in the renal medulla, with a significant reduction in allografts (p < 0.001). Furthermore, in transplanted patients a correlation between mean FA in the medulla and estimated GFR was observed (r = 0.72, p < 0.01). Tractography visualized changes in renal microstructure in patients with impaired allograft function. Changes in allograft function and microstructure can be detected and quantified using DTI. However, to prove the value of DTI for standard clinical application especially correlation of imaging findings and biopsy results is necessary.

• Neuronavigational guidance in craniofacial approaches for large (para)nasal tumors involving the anterior skull base and upper clival lesions.

  Authors: M Nakamura, T Stöver, T Rodt, O Majdani, M Lorenz, T Lenarz, J K Krauss

  European journal of surgical oncology : the journal of the European Society of Surgical Oncology and the British Association of Surgical Oncology. 01/2009;

  OBJECTIVE: Due to the destruction of osseous landmarks of the skull base or paranasal sinuses, the anatomical orientation during surgery of frontobasal or clival tumors with (para)nasal extension isOBJECTIVE: Due to the destruction of osseous landmarks of the skull base or paranasal sinuses, the anatomical orientation during surgery of frontobasal or clival tumors with (para)nasal extension is often challenging. In this relation computer assisted surgical (CAS) guidance might be a useful tool. Here, we explored the use of CAS in an interdisciplinary setting. METHODS: The surgical series consists of 13 patients who underwent a lateral rhinotomy combined with a subfrontal craniotomy in case of significant intracranial tumor extension. The procedures were planned and assisted by advanced CAS techniques with image fusion of CT and MRI. Tumors included carcinomas (one case associated with an olfactory groove meningioma), esthesioneuroblastoma, chordoma, chondrosarcoma and ganglioglioma. RESULTS: The application of CAS in the combined approaches was both safe and reliable for delineation of tumors and identification of vital structures hidden or encased by the tumors. There was no perioperative 30-day mortality; however two patients died 5 weeks and 5 months after craniofacial tumor resection due to worsening medical conditions. The most common perioperative morbidity was postoperative wound complication in two cases. Tumors were either removed completely, or subtotal resection was achieved allowing targeted postoperative radiotherapy. CONCLUSION: Craniofacial approaches with intraoperative neuronavigational guidance in a multidisciplinary setting allow safe resection of large tumors of the upper clivus and the paranasal sinuses involving the anterior skull base. Complex skull base surgery with the involvement of bony structures appears to be an ideal field for advanced navigation techniques given the lack of intraoperative shift of relevant structures.

• Large scan field, high spatial resolution flat-panel detector based volumetric CT of the whole human skull base and for maxillofacial imaging.

  Authors: S H Bartling, O Majdani, R Gupta, T Rodt, C Dullin, P F Fitzgerald, H Becker

  Dento maxillo facial radiology. 10/2007; 36(6):317-27.

  OBJECTIVES: To assess the feasibility of flat-panel detector based volumetric CT (fpVCT) scanning of the whole human skull base and maxillofacial region, which has thus far only been demonstrated onOBJECTIVES: To assess the feasibility of flat-panel detector based volumetric CT (fpVCT) scanning of the whole human skull base and maxillofacial region, which has thus far only been demonstrated on small, excised specimens. Flat-panel detectors offer more favourable imaging properties than image intensifiers. It is therefore likely that they will replace them in cone-beam CT scanners that are currently used to scan parts of the skull base and maxillofacial region. Furthermore, the resolution of current CT imaging limits diagnosis, surgical planning and intraoperative navigation within these regions. fpVCT might overcome these limitations because it offers higher resolution of high contrast structures than current CT. METHODS: Three embalmed cadaver heads were scanned in two scanners: an experimental fpVCT that offers a scan field large enough for a whole human head, and in a current multislice CT (MSCT). 28 structures were compared. RESULTS: Both scanners produced bone images of diagnostic quality. Small high contrast structures such as parts of the ossicular chain and thin bony laminas were better delineated in fpVCT than in MSCT. fpVCT of maxillofacial region and skull base was rated superior to MSCT (P=0.002) as found in this limited, experimental study. CONCLUSIONS: High spatial resolution fpVCT scanning of both regions in a whole human head is feasible and might be slightly superior to MSCT. fpVCT could improve diagnostic accuracy in selected cases, as well as surgical planning and intraoperative navigation accuracy.

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• [Fair in the face: modern diagnostics of midfacial trauma]

  Authors: J E W Zajaczek, T Rodt, M Keberle

  Der Radiologe. 08/2007; 47(7):591-7.

  Modern diagnostics of midfacial trauma are embedded in a diagnostic concept that is oriented to the therapeutic relevance for the individual. Critical analysis of the indicated and efficientModern diagnostics of midfacial trauma are embedded in a diagnostic concept that is oriented to the therapeutic relevance for the individual. Critical analysis of the indicated and efficient radiological method in the acute phase shows that MSCT is currently the method of choice in the diagnosis of midfacial trauma. Besides extensive acquisition of data in the shortest time the possibilities of modem post-processing provide a three-dimensional picture of the often complex injuries in real time. Other perilous injuries are often more important especially for the polytrauma patient. With modern scan protocols intracranial injuries as well as injuries of bone and soft tissue of the head and neck region can be diagnosed during a single examination. Radiology plays a key role for the economically oriented strategy of patient care.

• eLearning in education and advanced training in neuroradiology: introduction of a web-based teaching and learning application.

  Authors: J E W Zajaczek, F Götz, T Kupka, M Behrends, B Haubitz, F Donnerstag, T Rodt, G F Walter, H K Matthies, H Becker

  Neuroradiology. 10/2006; 48(9):640-6.

  INTRODUCTION: New information technologies offer the possibility of major improvements in the professional education and advanced training of physicians. The web-based, multimedia teaching andINTRODUCTION: New information technologies offer the possibility of major improvements in the professional education and advanced training of physicians. The web-based, multimedia teaching and learning application Schoolbook has been created and utilized for neuroradiology. METHODS: Schoolbook is technically based as a content management system and is realized in a LAMP environment. The content is generated with the help of the developed system and stored in a database. The layout is defined by a PHP application, and the webpages are generated from the system. RESULTS: Schoolbook is realized as an authoring tool so that it can be integrated into daily practice. This enables the teacher to autonomously process the content into the web-based application which is used for lectures, seminars and self-study. A multimedia case library is the central building block of Schoolbook for neuroradiology, whereby the learner is provided with original diagnostic and therapeutic data from numerous individual cases. The user can put individual emphasis on key learning points as there are various ways to work with the case histories. Besides the case-based way of teaching and learning, a systematically structured way of dealing with the content is available. CONCLUSION: eLearning offers various opportunities for teaching and learning in academic and scientific as well as in economic contexts. Web-based applications such as Schoolbook may be beneficial not only for basic university education but also for the realization of international educational programmes such as the European Master of Medical Science with a major in neuroradiology.

• Evaluation of surface and volume rendering in 3D-CT of facial fractures.

  Authors: T Rodt, S O Bartling, J E Zajaczek, M A Vafa, T Kapapa, O Majdani, J K Krauss, M Zumkeller, H Matthies, H Becker, J Kaminsky

  Dento maxillo facial radiology. 08/2006; 35(4):227-31.

  OBJECTIVES: Three-dimensional computed tomography (3D-CT) of facial fractures has been reported as beneficial using surface (SR) and volume rendering (VR). There are controversial statementsOBJECTIVES: Three-dimensional computed tomography (3D-CT) of facial fractures has been reported as beneficial using surface (SR) and volume rendering (VR). There are controversial statements concerning the preferable algorithm. The purpose of this study was to evaluate and compare SR and VR for clinical 3D-CT in facial fractures on an experimental basis. METHODS: Multislice CT was obtained in 22 patients with facial fractures using two data acquisition protocols. Five SR and VR post-processing protocols were applied. Five assessors independently evaluated the quality of visualization of the fracture gap and dislocated fragments as well as the overall image quality using a five-point rating scale. The potential benefit of the 3D-images for radiological diagnosis and presentation was evaluated. The influence of the data acquisition protocol was analysed. RESULTS: SR in general achieved better evaluation scores than VR at corresponding thresholds. Variation of evaluation scores for all criteria was found for SR and VR depending on the segmentation threshold. Apart from the overall image quality no significant influence of the data acquisition technique was found for the evaluated criteria. CONCLUSIONS: SR provided sufficient and time efficient means for 3D-visualization of facial fractures in this study. No diagnostic benefit of VR over SR was found.

• Increase of accuracy in intraoperative navigation through high resolution flat-panel Volume-CT: Experimental comparison to multi-slice-CT based navigation

  Authors: S. Bartling, M. Leinung, T. Rodt, C. Dullin, H. Becker, T. Lenarz, T. Stöver, O. Majdani

  Otology & Neurootology (accepted minor revisions). 01/2006;

• [3D-Visualisation of the middle ear by computer-assisted post-processing of helical multi-slice CT data]

  Authors: T Rodt, H P Burmeister, S Bartling, J Kaminsky, B Schwab, R Kikinis, H Becker

  Laryngo- rhino- otologie. 08/2004; 83(7):438-44.

  Post-processing of CT-data allows non-invasive 3D-Visualisation of the middle ear for diagnosis and surgical planning. In this study different post-processing techniques and the clinical applicationPost-processing of CT-data allows non-invasive 3D-Visualisation of the middle ear for diagnosis and surgical planning. In this study different post-processing techniques and the clinical application of a 3D-postprocessing algorithm in a large number of patients are presented. 20 normal patients, 6 dissected temporal bones and 213 patients with suspected middle ear pathology were examined using a low-dosage Multi-Slice CT protocol. Virtual endoscopic views of the middle ear and 3D-images of the ossicles were generated using a standardised algorithm. Evaluation of the image quality was performed. The virtual views of the dissected temporal bones were compared to real views. In 32 patients high-quality 3D-models of the individual anatomical structures were generated and displayed using different visualisation techniques. The standardised and evaluated method enabled visualisation of the normal middle ear anatomy. Assessment of different pathologies, especially malformation, trauma, implants and postoperative alterations, was facilitated. The high-quality 3D-models allowed precise imaging of the anatomical structures. 3D-Visualisation of the middle ear using CT-data is beneficial for radiological diagnosis and surgical planning in cases of complex middle ear pathology as a complementary examination technique.

• [Multisegmental image fusion of the spine]

  Authors: J Kaminsky, T Rodt, J Zajaczek, F Donnerstag, M Zumkeller

  Biomedizinische Technik. Biomedical engineering. 04/2004; 49(3):49-55.

  Fusion of medical images is a technique that permits the correlation of homologous anatomical structures in different imaging modalities on the basis of a spatial transformation of the data sets. CTFusion of medical images is a technique that permits the correlation of homologous anatomical structures in different imaging modalities on the basis of a spatial transformation of the data sets. CT and MRI of the spine provide complementary information of possible relevance for diagnostic and therapeutic decisions. Methods enabling a multisegmental CT-MRI fusion of the spine were developed. These solve the problem of altered spatial relationships of the individual anatomical structures due to differing patient positioning in successive data acquisitions. Routine clinical CT and MRI data of a thoracic section of the spine were obtained and transferred to a PC-workstation. Following segmentation of the CT-data, landmarks for each individual vertebra were defined in the CT and MRI data. For each individual vertebra the algorithm we developed then carried out a rigid registration of the CT information to the MR data. The fused data sets were presented as colour-coded images or on the basis of dynamic variation of transparency. To assess registration precision, fiducial registration errors (FRE) and target registration errors (TRE) were calculated. The algorithm permitted multi-segmental image fusion of the spine. The average time required for defining the landmarks was 22 seconds per landmark for CT, and 34 seconds per landmark for MR. The average FRE was 1.53 mm. The TRE for the vertebrae was less than 2 mm. The colour-coded images were particularly suitable for assessing the contours of the anatomical structures, whereas dynamic variation of the transparency of overlapping CT images enabled a better overall assessment of the spatial relationship of the anatomical structures. The algorithm permits precise multi-segmental fusion of CT and MR of the spine, which was not possible using current fusion-algorithms due to variations in the spatial orientation of the anatomical structures caused by different positioning of the axial skeleton in successive examinations.

• 3D visualisation of the middle ear and adjacent structures using reconstructed multi-slice CT datasets, correlating 3D images and virtual endoscopy to the 2D cross-sectional images.

  Authors: T Rodt, P Ratiu, H Becker, S Bartling, D F Kacher, M Anderson, F A Jolesz, R Kikinis

  Neuroradiology. 10/2002; 44(9):783-90.

  The 3D imaging of the middle ear facilitates better understanding of the patient's anatomy. Cross-sectional slices, however, often allow a more accurate evaluation of anatomical structures, as someThe 3D imaging of the middle ear facilitates better understanding of the patient's anatomy. Cross-sectional slices, however, often allow a more accurate evaluation of anatomical structures, as some detail may be lost through post-processing. In order to demonstrate the advantages of combining both approaches, we performed computed tomography (CT) imaging in two normal and 15 different pathological cases, and the 3D models were correlated to the cross-sectional CT slices. Reconstructed CT datasets were acquired by multi-slice CT. Post-processing was performed using the in-house software "3D Slicer", applying thresholding and manual segmentation. 3D models of the individual anatomical structures were generated and displayed in different colours. The display of relevant anatomical and pathological structures was evaluated in the greyscale 2D slices, 3D images, and the 2D slices showing the segmented 2D anatomy in different colours for each structure. Correlating 2D slices to the 3D models and virtual endoscopy helps to combine the advantages of each method. As generating 3D models can be extremely time-consuming, this approach can be a clinically applicable way of gaining a 3D understanding of the patient's anatomy by using models as a reference. Furthermore, it can help radiologists and otolaryngologists evaluating the 2D slices by adding the correct 3D information that would otherwise have to be mentally integrated. The method can be applied to radiological diagnosis, surgical planning, and especially, to teaching.

• Experimentelle Untersuchung einer neuen CT Technologie in der Felsenbeindiagnostik

  Authors: S. Bartling, T. Rodt, R. Gupta, Benno Paul Weber, Delphine Nain, R. Kikinis, A. Pfoh, H. Becker

  01/2002