Biomedical subjects

Christian Czerny

Publications and source records attributed to Christian Czerny.

17 recordsLinked to original sources

PubMed2007

CT-MR image data fusion for computer assisted navigated neurosurgery of temporal bone tumors.

PURPOSE: To demonstrate the value of multi detector computed tomography (MDCT) and magnetic resonance imaging (MRI) in the preoperative work up of temporal bone tumors and to present, especially, CT and MR image fusion for surgical planning and performance in computer assisted navigated neurosurgery of temporal bone tumors. MATERIALS AND METHODS: Fifteen patients with temporal bone tumors underwent MDCT and MRI. MDCT was performed in high-resolution bone window level setting in axial plane. The reconstructed MDCT slice thickness was 0.8 mm. MRI was performed in axial and coronal plane with T2-weighted fast spin-echo (FSE) sequences, un-enhanced and contrast-enhanced T1-weighted spin-echo (SE) sequences, and coronal T1-weighted SE sequences with fat suppression and with 3D T1-weighted gradient-echo (GE) contrast-enhanced sequences in axial plane. The 3D T1-weighted GE sequence had a slice thickness of 1mm. Image data sets of CT and 3D T1-weighted GE sequences were merged utilizing a workstation to create CT-MR fusion images. MDCT and MR images were separately used to depict and characterize lesions. The fusion images were utilized for interventional planning and intraoperative image guidance. The intraoperative accuracy of the navigation unit was measured, defined as the deviation between the same landmark in the navigation image and the patient. RESULTS: Tumorous lesions of bone and soft tissue were well delineated and characterized by CT and MR images. The images played a crucial role in the differentiation of benign and malignant pathologies, which consisted of 13 benign and 2 malignant tumors. The CT-MR fusion images supported the surgeon in preoperative planning and improved surgical performance. The mean intraoperative accuracy of the navigation system was 1.25 mm. CONCLUSION: CT and MRI are essential in the preoperative work up of temporal bone tumors. CT-MR image data fusion presents an accurate tool for planning the correct surgical procedure and is a benefit for the operational results in computer assisted navigated neurosurgery of temporal bone tumors.

Adult↗

PubMed2006

Osteonecrosis of the jaws and bisphosphonate treatment in cancer patients.

PURPOSE: Osteonecrosis of the jaws is described as an intraoral complication after administration of intravenous nitrogen-containing bisphosphonates. In a retrospective study, patients with osteonecrosis of the jaws after bisphosphonate treatment were evaluated with regard to diagnostic investigations and therapeutic management. PATIENTS AND METHODS: Seventeen patients with osteonecrosis of the jaws after bisphosphonate treatment who were referred to our department between July 2004 and June 2005 were included in this study. Computer tomography, magnetic resonance imaging, scintigraphy, bacteriology and biopsy were used in diagnostic evaluation. All patients were treated surgically. RESULTS: The reasons for bisphosphonate treatment were multiple myeloma in 12 patients, breast cancer with bone metastasis in four patients and histiocytosis X in one patient. Five patients had received intravenous pamidronate and 12 patients zoledronic acid. The median number of treatment cycles for pamidronate was 36 times (range 4-100) in 38 months (range 4-100). Zolendric acid was given 23.5 times (range 5-39) in 26 months (range 5-39). Nine patients had a lesion in the mandible, eight in the maxilla. Clinical symptoms were exposed bone, pain and local inflammation of the mucosa. Computer tomography showed sclerotic areas in the osteonecrosis zone. The biopsy did not show a metastatic lesion. Sequestrectomy and decortication was adequate in the follow-up. CONCLUSION: Nitrogen-containing bisphosphonates appear to be associated with the risk of developing osteonecrosis of the jaws. To reduce this risk, patients should be evaluated by a dentist before beginning treatment with intravenous bisphosphonates.

Adult↗

PubMed2006

MDCT versus digital radiography in the evaluation of bone healing in orthopedic patients.

OBJECTIVE: Assessment of bone healing in orthopedic patients is usually monitored by radiographs in two views. The purpose of our study was to compare multiplanar reconstructions from MDCT data sets with digital radiographs for assessing the extent of bone healing. MATERIALS AND METHODS: Forty-three orthopedic patients (19 women, 24 men) who underwent MDCT and radiography after arthrodesis, fractures, or spinal fusions were included in our study. MDCT was performed on an MX 8000IDT scanner and served as the gold standard. The technical parameters were adapted to the anatomic region. A bone algorithm for reconstruction was used (3,500/600 H). Multiplanar reconstructions were calculated in two orthogonal planes. All patients underwent digital radiography on a Multix FD system in two views according to standard procedures. Multiplanar reconstructions and radiographs were analyzed by two musculoskeletal radiologists in a consensus interpretation to determine bone healing using a semiquantitative approach. RESULTS: In 27 patients (63%), MDCT and digital radiography were concordant with regard to the extent of bone healing, whereas in 16 patients (37%) the results were not concordant. In eight patients (19%) digital radiographs underestimated the extent of bone healing, whereas in another eight patients (19%) they overestimated the degree of fusion. CONCLUSION: MDCT using high-quality 2D reformatting is recommended as the primary imaging technique for the evaluation of bone healing.

Female↗

PubMed2005

Diffusion weighted imaging of bone marrow pathologies.

Diffusion weighted imaging of non-CNS tissue has attracted much attention during the last years. Its capability of probing the microstructure of a biologic tissue at a sub-millimeter range is used to evaluate its diffusion capacity, which is tissue specific and can be used for tissue characterization. Processes involving bone marrow where the primary target for DWI during the last years. Most experience has been gained for differentiating benign from pathologic vertebral compression fractures, which can be reliably done when quantitative diffusion measurements are available. However, preliminary results exist indicating that this non-invasive technique may be a potential tool for therapy monitoring, which will revise the management of cancer patients. Moreover, this will be the first non-invasive and quantifiable tool for evaluating the effectiveness of modern tumor treatment. In this article, we will give an overview on the current status of DWI in the evaluation of bone marrow alterations; on currently available DWI techniques and a short out-look on future aspects of DWI in bone marrow pathologies.

Bone Marrow Diseases↗

PubMed2004

Audiological performance after cochlear implantation in children with inner ear malformations.

OBJECTIVES: To prove that cochlear implantation is a beneficial method of rehabilitation in deaf children with malformations of the inner ear. DESIGN: The evaluation of auditory responses to speech (EARS) test battery was performed on the children in this study after an average implant use of 3 years. RESULTS: Individual results of six children with inner ear anomalies receiving cochlear implants are presented in this study. Three of the patients showed an incomplete partition (Mondini dysplasia), one had a cochlear hypoplasia and two suffered from an intraoperative cerebrospinal fluid leak. The majority of the children in this study are successful implant users. Wherever possible, test scores are included and subjective case reports given. CONCLUSIONS: Results are similar to those in children with normal cochleas, therefore inner ear malformations found in as many as 20% of patients with congenital sensorineural hearing loss are no contraindication for cochlear implantation. Nevertheless, factors influencing the success of implantation are multiple, including a thorough preoperative radiological examination, a well-performed surgery and an individually tailored postoperative rehabilitation programme.

Audiometry, Speech↗

PubMed2003

Localized pericochlear hypoattenuating foci at temporal-bone thin-section CT in pediatric patients: nonpathologic differential diagnostic entity?

PURPOSE: To evaluate the prevalence of localized hypoattenuating areas in the cochlear otic capsule at temporal-bone thin-section computed tomography (CT) in pediatric patients and correlate the findings with clinical information. MATERIALS AND METHODS: Temporal-bone thin-section CT images obtained in 73 patients aged 0-9 years (20 Austrian, 53 Finnish; 36 female and 37 male patients) were evaluated for the presence of localized hypoattenuating foci in the region of the fissula ante fenestram of the otic capsule. Clinical information collected for all patients was also evaluated. The data were analyzed with a logistic regression model. RESULTS: Hypoattenuating areas in the region of the fissula ante fenestram were observed in 23 of 73 patients (32%). Hypoattenuating foci were substantially more prevalent in patients younger than 3 years than in those 3 years or older (odds ratio, 0.14; 95% CI: 0.04, 0.52; P =.001). The prevalence did not differ between sexes or according to clinical diagnosis. Only three of the 23 patients with hypoattenuating foci had clinical findings suggestive of otosclerosis, and none had osteogenesis imperfecta. After adjustment for age and sex, the finding was more prevalent among the Finnish patients (odds ratio, 5.4; 95% CI: 1.19, 24.52; P =.02) than among the Austrian patients. CONCLUSION: Hypoattenuating areas in the region of the fissula ante fenestram in the otic capsule at thin-section CT are prevalent among children younger than 3 years in the absence of clinical evidence of otosclerosis or osteogenesis imperfecta and appear in children up to 9 years old.

Child↗

PubMed2003

Suspected pulmonary embolism: enhancement of pulmonary arteries at deep-inspiration CT angiography--influence of patent foramen ovale and atrial-septal defect.

PURPOSE: To investigate if abnormal early contrast enhancement of the aorta and decreased attenuation of pulmonary arteries at deep-inspiration spiral computed tomographic (CT) angiography might be caused by a patent foramen ovale (PFO). MATERIALS AND METHODS: Two hundred forty-four spiral CT angiographic images of the pulmonary arteries obtained during deep inspiration in patients suspected of having pulmonary embolism (PE) were reviewed for evidence of abnormal early enhancement of the aorta. In 45 patients, enhancement of the ascending aorta was equal to or more than that of the pulmonary arteries. Nonenhanced or contrast material-enhanced echocardiography was performed in 39 of these cases. All CT images with abnormal enhancement patterns were graded for contrast quality with respect to sufficient enhancement of pulmonary arteries (four grades) at three anatomic levels: right and left main and lobar and segmental branches. In addition, all spiral CT angiographic images were evaluated concerning the diagnosis of PE and the grouping of central (main pulmonary artery to proximal lobar arteries) and peripheral (beyond proximal lobar branches) locations of emboli. Mean attenuation values of ascending aortas and main pulmonary arteries in group 1 (n = 244) were compared with those in groups 2 and 3 (n = 45) by means of the two-tailed Student t test for unpaired data (P <.05). RESULTS: Attenuation values for ascending aortas in group 1 were significantly lower than those in groups 2 and 3 (P <.001). Attenuation values in main pulmonary arteries were significantly higher in group 1 than in groups 2 and 3 (P <.001). Echocardiographic images showed an intracardiac right-to-left shunt in all 39 cases with abnormal contrast dynamics in the CT study (16% of the whole study population). Three patients had an atrial-septal defect, and 36 had a PFO. Images with a shunt had good (9%), intermediate (37%), fair (33%), and poor (23%) contrast of the pulmonary arteries. Sufficient vessel contrast for the diagnosis of PE could not be achieved in 27 of 45 patients with a shunt, but severe central PE could be ruled out. PE could be diagnosed in 31% of the 244 images, 58% were negative, and 11% were indeterminate. CONCLUSION: A PFO may frequently lead to insufficient attenuation of the pulmonary arteries, which potentially limits the diagnosis of PE if the examination is performed during deep inspiration.

Adolescent↗

PubMed2003

Automated vessel edge detection in velocity-encoded cine-MR (VEC-MR) flow measurements: a retrospective evaluation in critically ill patients.

OBJECTIVE: To assess feasibility of automated edge detection in magnetic resonance (MR) flow calculations in a clinical setting with critically ill patients. MATERIAL AND METHODS: Velocity encoded cine-MR (VEC-MR) flow measurements cross-sectional area (CSA), mean spatial velocity (MSV), instantaneous flow (IF), flow (F), 0.5 T Philips, TR 800-800, TE=8 ms, 30 degrees flip angle, FOV 280 mm, 128 x 256 matrix, temporal resolution 16 time frames/RR, VENC=120 cm/s) were obtained in 20 major thoracic human vessels (ascending aorta, main, right and left pulmonary artery-AAO, MPA, RPA, LPA) of five patients, suffering from severe chronic thromboembolic pulmonary hypertension (CTEPH). Flow maps were evaluated by two independent observers using conventional manual edge detection (INTER m/m). Flow calculations were performed by one observer using both, manual and automated edge detection (INTRA m/a), by a second observer using automated edge detection two times (INTRA a/a) and by two independent observers using automated edge detection (INTER a/a). Evaluation time was measured. Linear regression analysis and Student's t-test were performed. RESULTS: Overall regression coefficients (r2) for INTER m/m, INTRA m/a, INTER a/a and INTRA a/a, respectively, were as follows: CSA, 0.91, 0.91, 0.96, 0.98; MSV, 0.97, 0.99, 0.99, 0.99; IF, 0.98, 0.99, 0.99, 0.99; F, 0.98, 0.99, 0.99, 0.99. Manual CSA values differed significantly from automated data in MPA (P=0.01), RPA (P=0.0008) and LPA (P=0.02). No difference was found for the other assessed parameters of the pulmonary circulation. Average evaluation time per vessel was 20.2+/-2.6 min for manual and 2.1+/-0.7 min for automated edge detection (P<0.00001). CONCLUSION: The software program used provided reproducible data, lead to a 90% reduction in evaluation and calculation time and, therefore, might excel the utilization of VEC-MR flow measurements. Despite variations in the evaluation of the pulmonary circulation CSAs, flow assessment is feasible in critically ill patients.

Blood Flow Velocity↗

PubMed2003

'The Closer'-percutaneous vascular suture device: evaluation of safety and performance in neuroangiography.

OBJECTIVE: To evaluate the use of the suture mediated vascular closure device concerning practicability and safety in clinical angiography practice. MATERIAL AND METHODS: One hundred and seventeen patients (59 female, 58 male, mean age 40.9+/-13.4) underwent percutaneous closure of common femoral arterial puncture sites following diagnostic neuroangiography using the suture device 'the Closer' (Perclose Inc., Redwood City, CA, USA). Primary success, early problems (within 24 h) and late complications were evaluated. Complications were graded as minor and severe with or without need of surgical intervention and categorized by type. Parameters such as age, gender, sheath size and number of previous arterial punctures were evaluated with respect to complications. RESULTS: Percutaneous closure was primary successful in 85% (100/117). The overall complication rate was 32% (28% mild n=35, 4% severe n=6, which needed surgical intervention). All but one problem occurred within the first 24 h after the suture. Additional manual compression was necessary in 32 cases (25%). There was no significant difference in age and gender between the groups with and without complications. Sheath size was significantly larger (P<0.01) and numbers of preceeding angiograms were significantly higher (P<0.01) in the complications group compared with uncomplicated cases. CONCLUSION: The evaluated percutaneous vascular suture device is useful in clinical practice but limitations concerning patient selection seem to emerge in order to avoid complications.

Adult↗

PubMed2003

Impact of localization studies on feasibility of minimally invasive parathyroidectomy in an endemic goiter region.

BACKGROUND: A localized single-gland disease is the basis for minimally invasive parathyroidectomy (MIP) in primary hyperparathyroidism (PHPT). (99m)Tc sestamibi scanning (MIBI) and high-resolution Doppler ultrasonography (US) are well-established techniques used to localize enlarged parathyroid glands. Additionally, US enables physicians to diagnose subclinical thyroid abnormalities. The aim of this study was to optimize localization results, applying a combined interpretation of MIBI and US, and to analyze the influence of these results on the feasibility of MIP (endoscopic/video-assisted and open) in an endemic goiter region. STUDY DESIGN: One hundred fifty consecutive patients with sporadic PHPT were prospectively subjected to MIBI and US to localize parathyroid lesions and to review the morphology of the thyroid gland. Bilateral cervical exploration was performed in all patients. The feasibility of MIP was calculated retrospectively on the basis of surgical findings and biochemical outcomes at least 12 months postoperatively (normocalcemia in 148 of 150 patients [99%]). RESULTS: Forty-five percent of patients (67 of 148) would have been suitable for minimally invasive endoscopic or video-assisted parathyroid exploration. These procedures would have succeeded in 38% of patients (56 of 148). Sixty-four percent (94 of 148) would have been suitable for minimally invasive open parathyroidectomy, which would have succeeded in 55% (82 of 148 patients). CONCLUSIONS: Not all patients are suitable for MIP. A combined interpretation of MIBI and US results is helpful in planning targeted exploration. In an endemic goiter region minimally invasive open parathyroidectomy is applicable in significantly more patients than is endoscopic and video-assisted MIP.

Adenoma↗

PubMed2003

Computer-aided placement of endosseous oral implants in patients after ablative tumour surgery: assessment of accuracy.

The objective of this study was to evaluate the feasibility and accuracy of a novel surgical computer-aided navigation system for the placement of endosseous implants in patients after ablative tumour surgery. Pre-operative planning was performed by developing a prosthetic concept and modifying the implant position according to surgical requirements after high-resolution computed tomography (HRCT) scans with VISIT, a surgical planning and navigation software developed at the Vienna General Hospital. The pre-operative plan was transferred to the patients intraoperatively using surgical navigation software and optical tracking technology. The patients were HRCT-scanned again to compare the position of the implants with the pre-operative plan on reformatted CT-slices after matching of the pre- and post-operative data sets using the mutual information-technique. A total of 32 implants was evaluated. The mean deviation was 1.1 mm (range: 0-3.5 mm). The mean angular deviation of the implants was 6.4 degrees (range: 0.4 degrees - 17.4 degrees, variance: 13.3 degrees ). The results demonstrate, that adequate accuracy in placing endosseous oral implants can be delivered to patients with most difficult implantologic situations.

Dental Implantation, Endosseous↗

PubMed2003

[Imaging of diseases of the thyroid gland in Austria].

Imaging techniques for first line investigation of diseases of the thyroid gland are sonography (US) and scintigraphy, followed in dedicated cases by magnetic resonance imaging (MRI). Malignant lesions are generally hypoechoic on US with calcifications visible in some cases. The appearance of lymph node metastases is similar to that of the primary tumour. The various forms of goiter are the most commonly occurring forms of thyroid diseases in Austria, they appear heterogenous with hyperechoic as well as hypoechoic or anechoic nodes, in some cases with calcification. US findings of thyreoiditis are in acute forms of the disease more hypoechoic with diffuse swelling and hyperechoic with scar formations in chronic forms. Ectopic thyroid tissue occurs often in the form of thyroglossal duct cysts which are anechoic or hypoechoic.

Austria↗

PubMed2003

[Imaging of the parathyroid gland].

Diseases of the parathyroid gland are rare and are especially in case of hyperparathyroidism associated with hyperacalcaemia. Enlarged glands are, therefore, generally not detected with imaging modalities. The aim of imaging studies is to locialize abnormal glands. Ultrasound is the modality of choice for the primary investigation followed by nuclear medicine studies. Computed tomography or angiography with vein sampling should only be performed if the results of other investigations are equivocal. Magnetic resonance imaging is performed rarely in Austria with its high prevalence of endemic goiter.

Adenoma↗

PubMed2003

[Hybrid imaging for endocrine diseases: new perspectives].

Hybrid Imaging, also termed dual modality imaging, is the technique of fusionizing and interpreting images, that are gained from two different modalities constructed in one unit. Therefore, hybrid imaging may be regarded as a form of image fusion. Clinical applications in the field of endocrinology are the localization of neuroendocrine tumors and of lesions of the adrenal or the parathyroid glands. Significant diagnostic impact can be gained with this technique influencing the certainty of radiological reports.

Endocrine System Diseases↗

PubMed2002

Evaluation of computer-based area and volume measurement from coronal computed tomography scans in isolated blowout fractures of the orbital floor.

PURPOSE: In this retrospective study, we evaluated isolated blowout fractures of the orbital floor by region-of-interest measurements from coronal computed tomography (CT) scans and their relationship to ophthalmologic findings. PATIENTS AND METHODS: Fracture area and volume of displaced tissue of blowout fractures in 38 patients were measured from coronal CT scans. Measurement was performed by identifying distances (for area calculation) of the fracture and identifying areas (for volume calculation) of the displaced tissue in each CT slice. The calculated data were then compared with the amount of enophthalmos, presence of diplopia, and limitation of ocular motility. RESULTS: Orbital floor area (mean +/- SD) was 5.72 +/- 1.07 cm(2); fracture area, 2.63 +/- 1.20 cm(2); and the volume of displaced tissue, 1.15 +/- 0.91 mL. The average proportion of the fracture within the orbital floor was 45.3 +/- 17.6%. Fracture area and volume of displaced tissue were significantly positively correlated with enophthalmos and diplopia and not correlated with the limitation of ocular motility. For enophthalmos of 2 mm or greater, mean fracture area (mean +/- SD) was 4.08 +/- 1.09 cm(2) and volume of displaced tissue was 1.89 +/- 1.19 mL; for less than 2-mm enophthalmos, 1.98 +/- 0.83 cm(2) and 0.83 +/- 0.58 mL, respectively. Enophthalmos of 2 mm can be expected with 3.38 cm(2) of fracture area and 1.62 mL of displaced tissue. CONCLUSIONS: Region-of-interest measurement from coronal CT scan has an application in the assessment of patients with pure blowout fractures of the orbital floor and adds useful information in posttraumatic evaluation of orbital fractures.

Adolescent↗

PubMed2002

2D- and 3D-based measurements of orbital floor fractures from CT scans.

OBJECTIVE: Two methods for area and volume calculation of the orbit were evaluated following blow-out fractures of the orbital floor using computed tomography (CT) scans. MATERIAL AND METHODS: Isolated blow-out fractures of the orbital floor in human cadavers were simulated by fracturing the orbital floor and placing a defined volume of silicone within each defect. The area of fracture and the volume of silicone simulating herniated periorbital tissue were evaluated in 16 orbits by the use of a three-dimensional (3D) CT-based software package (Analyze((R)); Mayo Clinic, Rochester, MN, USA) and software based on two-dimensional (2D) coronal CT scans. Both methods were compared with direct anatomical measurements and evaluated with Lin's concordance coefficient (rho(c)). RESULTS: Between-method concordance of area and volume calculation were rho(c)=0.962, and 0.872 for the 3D-CT-based method, and 0.981 and 0.952 for the 2D-CT method, respectively. The time allocated for measurement was significantly longer for the 3D-CT than for the 2D-CT method (p<0.001). CONCLUSION: Calculations of blow-out fractures of the orbital floor by 3D-CT and 2D-CT method are accurate for assessing the area of fracture and the volume of herniated tissue. Lesser processing time and simple usage favour the 2D-CT-based calculation method.

Cadaver↗

PubMedDate not supplied

Interactive stereotaxic teleassistance of remote experts during arthroscopic procedures.

This article describes the technical setup for stereotaxic telesurgical assistance for arthroscopic procedures. It also outlines the current state, limitations, and feasibility of this technical development. Teleassistance or teleconsultation implemented in endoscopic or arthroscopic procedures have not yet been reported. In this study, 7 computer-assisted arthroscopies of the temporomandibular joint were supported by extramural experts via interactive stereotaxic teleconsultation from distant locations. The external experts were supplied with close to real-time video, audio, and stereotaxic navigation data directly from the operation site. This setup allows the surgeons and external experts to interactively determine portals, target structures, and instrument positions relative to the patient's anatomy and to discuss any step of the procedures. Optoelectronic tracking interfaced to computer- based navigation technology allowed precise positioning of instruments for single or multiple temporomandibular joint punctures. The average error of digitizing probe measurements was 1.3 mm (range, 0.0 to 2.5 mm) and the average standard deviation was 0.7 mm (range, 0.4 to 0.9 mm). Evaluation of the reliability and accuracy of this technique suggests that it is sufficient for controlled navigation, even inside the small temporomandibular joint, a fact that encourages further applications for arthroscopy in general. The minimum requirement for high-quality video transmission for teleassisted procedures are integrated services digital network (ISDN) connections. Conventional ISDN-based videoconferencing can be combined with computer-aided intraoperative navigation. Transmission control protocol/internet protocol (TCP/IP)-based stereotaxic teleassistance data transmission via ATM or satellite seem to be promising techniques to considerably improve the field of arthroscopy.

Aged↗