ABSTRACT
PURPOSE: Are implanted central venous port catheters suitable for contrast media pressure (power) injection in computed tomography? MATERIAL AND METHODS: In an in vitro study 100 ml of contrast medium (Ultravist 370, Schering, Berlin, Deutschland) was injected through 20 different port catheter systems using a power injector (Stellant, Medrad, Inianola, USA) with a pressure limit of 325 PSI. The injection rate was increased from 2 ml/s to 10 ml/s in increments of 2 ml/s. The maximum injection pressure and maximum injection rate were assessed. RESULTS: An injection rate of 2 ml/s was possible in all catheter systems. Injection rates of 4 ml/s in 18 systems, 6 ml/s in 13 systems and 8 ml/s in 6 systems were achieved. With a given pressure limit of 325 PSI an injection rate of 10 ml/s was not possible in any of the port catheter systems. There were no catheter ruptures, catheter disconnections or contrast extravasations noted. CONCLUSION: Power injection of contrast media with a pressure limit of 325 PSI seems to be tolerated by port catheter systems. Most of the evaluated port systems allow flow rates suitable for multislice computed tomography requiring rapid contrast injection.
Subject(s)
Catheterization, Central Venous/instrumentation , Contrast Media/administration & dosage , Injections, Intravenous/instrumentation , Iohexol/analogs & derivatives , Tomography, X-Ray Computed/instrumentation , Tomography, X-Ray Computed/methods , Catheterization, Central Venous/methods , Equipment Design , Equipment Failure Analysis , Humans , In Vitro Techniques , Injections, Intravenous/methods , Iohexol/administration & dosage , PressureABSTRACT
PURPOSE: To compare virtual with flexible bronchoscopy for the detection of bronchial stenoses. MATERIALS AND METHODS: In a retrospective study, we compared the results of 26 patients, who had clinical suspected pathologies of the tracheobronchial airways and underwent both flexible bronchoscopy and multislice CT with 3D surface rendering of the airways. Flexible bronchoscopy and virtual bronchoscopy were compared as to the rate of detecting bronchial stenoses. For statistical analysis, we divided the tracheobronchial tree in the following sections: trachea, 2 main bronchi, 6 lobar bronchi, 18 segmental bronchi and 36 subsegmental bronchi, corresponding to 63 bronchial sections for each patient (on average) and a total of 1638 bronchial sections for all 26 patients. We graded the bronchial stenosis as less than 50 %, as 50 to 95 % and as complete obstruction. RESULTS: Virtual bronchoscopy detected 25 bronchial stenoses, while flexible bronchoscopy only revealed 17 stenoses. Stenoses with a diameter less than 50 % were found with virtual bronchoscopy 14 times and with flexible bronchoscopy 10 times. Stenoses with a diameter between 50 and 95 % were detected 7 and 4 times, respectively, and complete obstructions 4 and 3 times, respectively. Tracheobronchial stenoses were well recognized with virtual bronchoscopy. Moreover, the virtual method enabled the visualization of high-grade stenoses and post-stenotic areas that could not be passed by the fiberoptic bronchoscope. Virtual bronchoscopy detected stenoses at a higher rate but the difference was not statistically significant (stenoses < 50 %: p = 0.352, 50 - 95 %: p = 0.339, complete obstruction: p = 0.696). CONCLUSION: Virtual bronchoscopy is a useful non-invasive method for the diagnostic evaluation of the tracheobronchial tree. In comparison with flexible bronchoscopy, virtual bronchoscopy is superior in revealing high-grade stenoses and visualizing post-stenotic areas.
Subject(s)
Bronchial Diseases/diagnosis , Bronchoscopy/methods , Adult , Aged , Aged, 80 and over , Algorithms , Bronchial Diseases/diagnostic imaging , Bronchial Neoplasms/diagnosis , Bronchial Neoplasms/diagnostic imaging , Bronchitis/diagnosis , Bronchitis/diagnostic imaging , Chi-Square Distribution , Constriction, Pathologic/diagnosis , Constriction, Pathologic/diagnostic imaging , Diagnosis, Differential , Esophageal Neoplasms/diagnosis , Esophageal Neoplasms/diagnostic imaging , Female , Fiber Optic Technology , Humans , Image Processing, Computer-Assisted , Imaging, Three-Dimensional , Male , Middle Aged , Pneumonia/diagnosis , Pneumonia/diagnostic imaging , Retrospective Studies , Tomography, Spiral Computed , Tracheal Stenosis/diagnosis , Tracheal Stenosis/diagnostic imagingABSTRACT
PURPOSE: Confirmation of a new technique for evaluating bone mineral density (BMD). Colored coded imaging of topographical distribution of bone mineral density in the spongy substance. METHOD: For 20 patients, dental CT examinations of the mandible were made in axial slices. Spongy substance and cortical bone pixels were automatically segmented at foramina mentalia level by means of threshold fixation. The segments were separated in areas relevant to implantology. For each region, BMD was measured by means of quantitative computed tomography (QCT). Spongiose substance of 20 mandibles was segmented by using three threshold intervals to image topographical BMD distribution. RESULTS: Cortical bone and spongy substance could be automatically segmented for 20 mandibles. BMD could be measured in each region. The results were comparable with those of other techniques. Three threshold intervals were segmented for 20 mandibles in the spongy substance to depict topographical BMD distribution. CONCLUSIONS: Areas of low BMD can be detected by imaging topographical BMD distribution. This way, subjective rating by the examiner is eliminated.
