Accuracy of a 3D fluoroscopic navigation system using a flat-panel detector-equipped C-arm.

OBJECTIVE: The aim of this study was to evaluate the accuracy of a novel 3-dimensional (3D) fluoroscopic navigation system using a flat-panel detector-equipped C-arm, focusing on the influence of the distance from the center of fluoroscopic imaging on navigation accuracy. MATERIALS AND METHODS: A geometric phantom was made using a Styrofoam cube with 25 markers, each consisting of a metal ball 1.5 mm in diameter, fixed in a cross arrangement at 1-cm intervals. Hip joint surgery was simulated using a set of dry pelvic and femoral bones. A total of eight markers were fixed to the acetabulum and proximal femur. RESULTS: In the geometric phantom study, mean target registration error (TRE) was 0.7 mm (range: 0.1-1.5). The TRE of markers located at 5 cm from the imaging center was significantly higher than the TRE of markers located at 1 and 2 cm. However, the TRE was <1 mm in 90% of the overall trials and <1.5 mm in 100%. In the dry bone study, the mean TRE was 0.9 mm (range: 0.7-1.5) over the acetabulum and 1.0 mm (range: 0.5-1.4) over the femur. No significant difference in TRE was seen between the acetabulum and proximal femur. CONCLUSION: The accuracy of this novel 3D fluoroscopic navigation system was considered acceptable for clinical application. A 3D C-arm equipped with a flat-panel detector could increase the feasibility of 3D fluoroscopic navigation by reducing the effects of image distortion on navigation accuracy.

MBS measurement tool for swallow impairment--MBSImp: establishing a standard.

The aim of this study was to test reliability, content, construct, and external validity of a new modified barium swallowing study (MBSS) tool (MBSImp) that is used to quantify swallowing impairment. Multiple regression, confirmatory factor, and correlation analyses were used to analyze 300 in- and outpatients with heterogeneous medical and surgical diagnoses who were sequentially referred for MBS exams at a university medical center and private tertiary care community hospital. Main outcome measures were the MBSImp and index scores of aspiration, health status, and quality of life. Inter- and intrarater concordance were 80% or greater for blinded scoring of MBSSs. Regression analysis revealed contributions of eight of nine swallow types to impressions of overall swallowing impairment (p < or = 0.05). Factor analysis revealed 13 significant components (loadings >/= 0.5) that formed two impairment groupings (oral and pharyngeal). Significant correlations were found between Oral and Pharyngeal Impairment scores and Penetration-Aspiration Scale scores, and indexes of intake status, nutrition, health status, and quality of life. The MBSImp demonstrated clinical practicality, favorable inter- and intrarater reliability following standardized training, content, and external validity. This study reflects potential for establishment of a new standard for quantification and comparison of oropharyngeal swallowing impairment across patient diagnoses as measured on MBSS.

Australian speech-language pathologists' knowledge and practice of radiation protection while performing videofluoroscopic swallowing studies.

During a videofluoroscopic swallowing study (VFSS), speech and language pathologists (SLPs) are potentially exposed to radiation. To effectively limit unnecessary exposure, SLPs performing VFSS are encouraged to actively shield themselves and to be monitored by radiation-monitoring badges. The aim of this research was to assess the level of current knowledge and practice of radiation protection among SLPs performing this procedure. A questionnaire was distributed via Speech Pathology Australia (SPA) and the Australasian Dysphagia Newsletter (ADN). Sixty-nine questionnaires were returned. The results revealed that participants had received some radiation protection training, which provided them with general knowledge on radiation protection. Participants indicated a lack of formal education and were unsure of the adequacy of the information provided. Ninety-seven percent of participants always wore lead aprons, 76% always wore thyroid shields, and 36% wore radiation-monitoring badges. The researchers recommend that education on radiation protection and safety be provided for SLPs at university level to educate them before they enter the workplace. It is also recommended that SLPs always wear lead aprons, thyroid shields, and radiation-monitoring badges.

The stability, reliability, and validity of videofluoroscopy measures for patients with head and neck cancer.

The purpose of this study was to contrast the psychometric properties (stability, test-retest reliability, construct, and concurrent validity) of three different tools used for evaluating videofluoroscopy swallowing studies (VFSS): (1) rating the presence or absence of a swallowing disorder, (2) the Bethlehem Assessment Scale (BAS), and (3) biomechanical measures. These three tools were applied to the same three examinations of two different consistencies (liquid and semisolid), taken from 40 VFSSs of patients with head and neck (H&N) cancer. Stability of swallowing across three swallows was a concern for three measures with the liquid consistency and nine measures with the semisolid consistency. Test-retest reliability was found to vary considerably for the two consistencies (liquids, 0.53-1.00; semisolids, 0.45-1.00). Examination of construct validity of the BAS and biomechanical measures indicated that six factors represented swallowing function, but different factors represented swallowing under liquid and semisolid conditions. Concurrent validity of the presence/absence of disorder variables was less than adequate. These results are discussed in the following contexts: (1) psychometric properties of VFSS may not be adequate for clinical and research environments and (2) psychometric properties of VFSS measures appear to vary as a function of bolus consistency.

Utility of ambulatory pH monitoring and videofluoroscopy for the evaluation of patients with globus pharyngeus.

Globus pharyngeous is not an uncommon disorder. The precise pathophysiology remains unclear. The aim of this study was to assess the clinical value of videofluoroscopy and ambulatory pH monitoring in patients with globus pharyngeus. Twenty-three patients (11M/12F, age range = 21-74 yr, mean = 50 yr) with globus pharyngeus entered the study. Radiographic examination of the pharynx and esophagus included videofluoroscopy and static radiography. A dual probe to measure the proximal and distal intraesophageal pH was inserted for 24 h. The results of dual-probe pH monitoring were normal in all patients. Videofluoroscopic results were abnormal in 8 patients, with 5 patients having laryngeal aspiration, 2 having stasis of barium in the vallecula and pyriform sinuses, and 4 having poor pharyngeal elevation. Cervical osteophytes were found in 13 patients with a frequent location at the C5-6 level. Ambulatory pH monitoring seemed to be less helpful for the evaluation of globus pharyngeus without reflux-like symptoms. Pharyngeal dysfunction is detected in a substantial proportion of patients by videofluoroscopy and radiography.

Radiation dose in videofluoroscopic swallow studies.

Videofluoroscopy has become an increasingly important armament in the investigation and assessment of swallowing disorders. However, very little work has been published on the radiation dose used in such examinations and currently there is no national diagnostic reference level in the United Kingdom. Videofluoroscopy in our hospital is performed predominantly by one radiologist (IZM) in a single fluoroscopy room. We recorded the screening times of 230 patients over a 45-month period. Screening time ranged from 18 to 564 s (median = 171 s) associated with a median dose-area product of 1.4 Gy cm(2). This is below the third quartile level of 2.7 Gy cm(2) for all such examinations performed across the northern England. The effective dose associated with a typical videofluoroscopy dose-area product is 0.2 mSv. Videofluoroscopy is the most appropriate instrumental examination for assessing oropharyngeal swallow biomechanics and intervention strategies. This data set is based on the largest number of videofluoroscopy swallow studies published to date. Our results show that videofluoroscopy can be performed using minimal radiation doses.

[Design principles, structure, and specific features of kardiovid computer diagnostic system].

The design principles and hardware implementation of Kardiovid computer diagnostic system are considered. The system is intended for diagnosis of the state of cardiovascular system on the basis of the results of electrocardiographic and fluorographic examinations. It provides simulation and visualization of the state of cardiovascular system.

Comparison of a digital flat-panel versus screen-film, photofluorography and storage-phosphor systems by detection of simulated lung adenocarcinoma lesions using hard copy images.

The purpose of this study was to compare hard copy images from a flat-panel detector digital radiography system with conventional radiography, photofluorographic radiography and storage phosphor radiography for the detection of simulated lung adenocarcinoma lesions and also for radiation dose. To test the diagnostic performance of these four systems, the authors used 15 types of lung adenocarcinoma phantom according to Noguchi's classification and an anthropomorphic chest phantom. The visual evaluation of tumour detectability by four radiologists and two general thoracic surgeons was examined with a five-level confidence scale. Lung doses were measured with glass dosemeters for the chest radiology systems under the conditions used by each hospital and centre. Our results indicated that flat-panel detector digital radiography and storage phosphor radiography are not necessarily superior to conventional radiography and photofluorographic radiography for detecting lung adenocarcinomas when only hard copy images are used, and this suggests a need to carefully optimize chest radiography.

[On the X-ray acquisition parameters in AXIOM artis].

This article analyzes mainly the X-ray imaging acquisition parameters in AXIOM Artis X-ray equipment, the relationship between the parameters, and how to select acquisition parameters in cardioangiography. We have sought a set of X-ray imaging acquisition parameters for producing optimal image in cardioangiography.

[Information technologies for scanning X-ray radiography].

Digital technologies have been widely used in X-rays diagnostics, including computer tomography, magnetic-resonance tomography, digital radiography etc. Digital technologies for image analysis essentially change all arrangements and procedures of preventive examinations made at patient-care facilities. As for digital fluorography, the basic principles of fluorography diagnostic room are standard but for one arrangement-the unit is controlled via a computer-assisted working place (CAWP) by the radiologist assistant; the room of radiologist is also equipped with CAWP. Admittedly, a key issue in general fluorographic examinations is registration of patients and preparation of them for the procedure. Contemplated in the paper are new potentialities of digital fluorography of big number of patients by low-dose fluorography (LDF, equipment manufacturer/Orel, Russia) which enhance the rate and quality of diagnostics.

[Digital videofluorography and esophageal achalasia: from diagnosis to follow-up]. / Videofluorografia digitale e acalasia esofagea: dalla diagnosi al follow-up postoperatorio.

The aim of this retrospective study was to evaluate the use of digital videofluorography in the preoperative and postoperative management of esophageal achalasia surgical treatment. From 1990 to 2004, 25 patients with achalasia, diagnosed by digital videofluorography and confirmed by motility studies and endoscopy, underwent surgery. All patients underwent digital videofluorography at 1, 6 and 12 months in order to evaluate the completeness of the myotomy and the efficacy of the antireflux procedures. At postoperative videofluorography esophageal transit time was decreased in all patients (100%); esophageal motor activity was unchanged in 23 (92%), and modified in two patients (8%) with onset of peristaltic-like motor activity; 8 patients (35%) presented decreased preoperative dilatation; all patients had a WST negative for post-myotomy reflux. On the basis of our experience and the advantages of the procedure we suggest videofluorography as a first-approach diagnostic examination useful for surgical indications and postoperative follow-up in achalasic patients.

[Experience in using a mobile digital fluorograph-equipped laboratory].

The authors share their experience in using a KFP-FC-RP digital fluorograph for mass fluorographic studies in a mobile fluorographic laboratory (on the basis of a ZIL-5301 EO automobile with a module body and an APCF-01 (ProScan-2000) fluograph made by ZAO "RENTGENPROM"). Studies were performed at the enterprises of Moscow and the Moscow Region. How the work of the mobile laboratory is organized is described. Since the able-bodied population was chiefly surveyed, the efficiency of the work can be considered rather high. The experience has shown that the use of a mobile fluorographic laboratory for mass examinations at the enterprises by a health care facility is much more effective and profitable than that of a permanent laboratory.

[Use of low-dose digital fluorography in patients with acute infiltrative pulmonary processes]. / Ispol'zovanie malodoznoi tsifrovoi fliuorografii v obsledovanii bol'nykh s ostrymi infil'trativnymi protsessami v legkikh.

Basic purpose of issue was the attempt of a rating of a role and place modern digital chest fluorography in complex diagnostics of lower respiratory diseases accompanied acute pulmonary infiltrates. We studied 232 adults who hospitalized with community-acquired pneumonia (CAP) to Saratov Military Medical School Hospital during 1999-2003. In integration of methods of research the role digital chest fluorography as way of primary diagnostics and conducting means of the analysis of technology of rendering of medical aid is emphasized. At the expense of use of the developed algorithm of methods of beam visualization at the control of a course of stationary treatment of the patients CAP it was possible to decrease length of stay for 2.5 day.

A comparison of diagnostic accuracy of a newly developed photofluorographic panoramic system with conventional panoramic radiography.

OBJECTIVES: To compare the diagnostic accuracy of a prototype photofluorographic panoramic system with that of a conventional panoramic system. METHODS: We used 14 human skulls with four artificial apical bone defects in each and 13 clinical cases with 21 periapical lesions. Six dental radiologists and six senior dental students rated the presence of defects on each image on a five-point scale. Receiver Operating Characteristic (ROC) analysis was performed and the area under each curve (Az) was compared as an index of accuracy. Statistical significance was set at P<0.05. RESULTS: There were no significant differences between the photofluorographic and the conventional panoramic systems (P=0.074) in detecting artificial apical defects. However, there were significant differences (P=0.03) in detecting natural defects. CONCLUSIONS: The diagnostic accuracy of the prototype photofluorographic panoramic system appears comparable with that of the conventional panoramic system. However, variability may arise from the observers' diagnostic experience and training.

A novel panoramic machine for photofluorography.

OBJECTIVE: To describe the main features of a prototype panoramic X-ray machine modified for photofluorography. METHODS: The prototype PTM 2001 (Asahi Roentgen, Kyoto, Japan) consists of a conventional panoramic machine with a modified X-ray generator and incorporating a 9-inch image intensifier and a photofluorographic camera. RESULTS: The photofluorographic panoramic radiograph is reduced in size by 60% compared with conventional images. Using 10 cm x 45.7 m photoradiographic film 250 panoramic images can be continuously obtained. Examination time is shorter since cassette changes are not necessary. The radiation dose-in-air, measured in front of the secondary collimator, is 174 muGy. CONCLUSIONS: The advantages of the photofluorographic panoramic radiography include cost economy, shorter examination time and lower radiation exposure.

Tongue-jaw linkages in human feeding: a preliminary videofluorographic study.

Motions of the tongue and jaw are closely coupled during feeding in mammals, but this relation has not been studied in humans. A videofluorographic method for measuring tongue movement relative to jaw motion using small radiopaque markers affixed to the tongue with dental adhesive was developed and tested in five individuals. Sagittal movements of the anterior tongue marker (ATM) and the lower jaw were measured for complete feeding sequences with a computerized image-analysis system. The ATM and jaw moved in loosely linked, semirhythmic cycles. Vertical and horizontal maxima of ATM motion were determined for each motion cycle in relation to maximum and minimum gape (greatest jaw opening and closing, respectively). The amplitude of tongue movements and their timing differed between hard and soft foods (p < 0.001). For both food types, motions varied as the feeding sequence progressed from ingestion to terminal swallow (p < 0.001). A basic temporal sequence was found in 70% of the 224 cycles analysed. On average, the ATM reached its most inferior position just after maximum gape, its most posterior during jaw closing, its most superior just after minimum gape, and its most anterior during jaw opening (p < 0.001). This study confirms that tongue and jaw movements are linked during human feeding, as they are in other mammals.

An analysis of studies comparing electrical impedance tomography with x-ray videofluoroscopy in the assessment of swallowing.

Electrical impedance tomography can be used to record the conductivity change occurring in the neck during a swallow. X-ray videofluoroscopy provides excellent anatomical detail of the structures involved in swallowing and of the position of the swallowed bolus. The two techniques have been performed simultaneously on seven patients with swallowing problems to establish what produces the peak change in conductivity when a solution of low conductivity is swallowed. The results suggest that the exclusion of air from the larynx and pharynx is the major factor influencing the change in conductivity when a solution of low conductivity is swallowed.