Use of a single stent for double ureter support in transplantation

Economical applications of teleradiology and telemedicine are limited to the existing telephone network infrastructure, which greatly limits the speed of digital information transfer. Telephone lines are inherently slow, requiring image transmission times to be unacceptably long for large, complex, or numerous images. JPEG (Joint Photographic Experts Group) image transmission has been shown to compress images to 10% of the original file size without a noticeable change in the quality of the image. This study was carried out to assess the quality of medical diagnostic images after JPEG compression and decompression. X-rays, computed tomography scans, and ultrasound samples were compressed and decompressed using JPEG. The compressed JPEG images were indistinguishable from the original images. The JPEG images were approximately 10% of the original file size. This would reduce image transmission times by 90% (eg, an unacceptable time of 50 minutes would be reduced to an acceptable time of 5 minutes). JPEG can be used to optimize teleradiology and telemedicine.     

Three-dimensional display of cardiac structures using reconstructed magnetic resonance imaging

It is sometimes difficult to understand the three-dimensional (3D) relationship of cardiac and mediastinal structures despite advances in magnetic resonance (MR) imaging techniques. We present a low-cost system for 3D reconstruction of the major mediastinal structures by processing the MR imaging data on a NeXT workstation. MR images of multisection, multiphase, spin-echo techniques stored in a picture archiving and communication system (PACS) data base were used for the reconstruction. The computer program obtained the contours of the multiple components of the mediastinal structures by the combination of automatic and manual procedure. The bundled software of a 3D kit was used for surface rendering of hidden surface removal, shading of the visible parts of the surfaces, perspective transformation, and motion parallax by rotation of the surfaces. 3D reconstruction was performed in 15 patients with cardiac diseases, and the 3D-reconstructed images were compared with the plain chest x rays of the patients. The 3D presentation clearly showed the complex anatomy of cardiovascular diseases and helped elucidate the misconceptions in the interpretation of the plain chest x rays. Our 3D images are used for education and should be viewed by medical students and beginners in radiology at an individual pace with plain chest radiographs, MR images, and legends. Although applied to the heart and the great vessels in this report, this system is also applicable to other structures.     

Inhibin-B: the physiologic basis of the clomiphene citrate challenge test for ovarian reserve screening

Disseminated tuberculosis was diagnosed at the autopsy of a 65-day-old premature infant who died in a 52-bed neonatal intensive care unit (NICU). Both parents and one sibling had previously had positive tuberculin skin tests (TSTs); none had active pulmonary tuberculosis, but a second sibling had hilar adenopathy. Congenital transmission was confirmed by isolation of Mycobacterium tuberculosis from the mother's endometrium and the infant's lung tissue. Both strains were identical by DNA restriction fragment analysis. TSTs were performed on 14 neonates, 27 NICU visitors, 11 contacts of the family, and 260 health care workers. TST conversion occurred in two nurses (0.8%); both had normal chest radiographs and received isoniazid therapy. Exposed neonates had negative chest radiographs, had negative gastric aspirates for acid-fast bacilli, and received isoniazid preventive therapy. Diagnosis of congenital tuberculosis requires a high index of suspicion. Transmission of tuberculosis in the NICU setting is unusual but can occur.     

Brain death and organ donation

Large-scale picture archiving and communication systems (PACS) have not been widely implemented in this or other countries. In almost all radiology departments film remains the medium for diagnostic interpretation and image archive. Chest imaging is the dominant screening examination performed within most imaging departments and as such, is an extremely high-volume, low-margin examination. Digital technologies are being applied to chest imaging to overcome limitations of screen-film receptors (limited latitude) and current film management systems (single-image copy). Efficient management of images and information is essential to the success of a chest imaging program. In this article we report on a digital imaging and communications in medicine (DICOM)-based centralized printing network for chest imaging. The system components and their operational characteristics are described. Our experience integrating DICOM-compliant equipment supplied by several vendors is described. We conclude that the print model supported by DICOM is adequate for cross-sectional (eg, computed tomography and magnetic resonance) imaging but is too simplistic to be generally applied to projection radiography.     

An evaluation of the signal and noise characteristics of four CCD-based film digitizers

Film digitizers are common devices in radiology departments involved with picture archive and communication systems (PACS) and teleradiology. In this paper, we studied the performance of film digitizers based on charge-coupled device detectors (CCD digitizers), and compared this with the performance of a laser digitizer (the de facto standard). Our focus was on the assessment of signal, noise and useful optical density range performance. A function (L* delta D) derived from the Rose model was used to evaluate these parameters in absolute terms, based their predicted ability to detect objects of specific size and optical density difference with respect to background. We studied CCD digitizers from four different vendors and found that none was able to reliably operate up to the maximum density of 3.0 required to digitize plain radiographs, while the laser digitizer was capable of this task. Our analysis also indicated that two of the four CCD digitizers were adequate for digitizing laser-printed cross-sectional images in certain cases. Finally, our analysis indicated that digitization of SMPTE pattern films along with visual assessment of the 5% and 95% contrast patches was not sufficient for determining the utility of film digitizers for clinical tasks. Computation of the L* delta D function provides a useful means of assessing the performance of film digitizers (e.g., for acceptance testing and quality control), and this technique may be adaptable for evaluation of other digital imaging modalities.     

Comparison between morphologic changes seen on high-resolution CT and regional pulmonary perfusion seen on SPECT in patients with cystic fibrosis

OBJECTIVE: To evaluate the relationship between morphologic findings seen on high-resolution computed tomography (HRCT) of the lung and regional lung perfusion depicted on single photon-emission computed tomography (SPECT) pulmonary perfusion imaging in patients with cystic fibrosis. MATERIALS AND METHODS: Ten HRCT and 10 technetium-99 m macroaggregated albumin SPECT pulmonary perfusion imaging studies were performed on eight young adult patients who were considered to be clinically well and have mild to moderate cystic fibrosis. HRCT scans of the chest were evaluated using a CT scoring system which included grading of bronchiectasis, peribronchial thickening, hyperlucency, bullae, collapse/consolidation, and mucus plugging. Each lung was divided into six anatomic zones which were independently scored. A lung perfusion score (between 0 and 100), reflecting the percentage of compromised lung, was estimated for each zone. Axial lung perfusion SPECT images were matched anatomically to HRCT images. Lung function was considered compromised when the counts per pixel were less than 25 % of the count level seen in an area of the same patient's lung which was judged to be normal. RESULTS: There was a statistically significant relationship (P = 0.0001) between HRCT total scores and SPECT lung perfusion scores as well as between hyperlucency scores by HRCT and the SPECT lung perfusion scores. However, the HRCT score was a poor predictor of the lung perfusion score in zones with intermediate HRCT scores, which constituted 106 of 120 zones. CONCLUSION: Morphologic changes depicted by HRCT correlate with decreased lung pefusion on SPECT. However, HRCT changes accurately predict regional lung function only in the most normal and severely diseased lung zones.     

The temperature of inspired air influences respiratory water loss in young lambs

We report a simple, four-step procedure for bedside treatment of infants on mechanical ventilation who have various degree of lung collapse unresponsive to conventional instillation of saline followed by chest percussion with endotracheal suctioning. The technique involves hyperoxygenation by bagging with 100% oxygen, deep endotracheal instillation of 0.25-0.5 mL/kg sterile saline, bagging with momentary inspiratory hold, followed by release of the hold and simultaneous forced exhalation and vibration to simulate cough, and endotracheal suctioning. This procedure was repeated three to five times on the affected side and at least once on the unaffected side; it resulted in notably improved lung expansion in 48 of 57 infants, documented by chest radiographs. The 57 infants included 48 (84%) whose chest radiographs showed airways occluded by mucus ("no air bronchograms") and 7 (16%) whose chest radiographs showed patent airways ("air bronchograms"). The technique is less successful in the latter group of patients in whom material obstructing proximal and intermediate airways has already been removed or displaced to distal airways, or a parenchymal infection has developed.     

Clinical evaluation of single-exposure dual-energy subtraction chest radiography: with FCR 9501 ES]

Using the one-shot energy subtraction method, we took chest radiography of 1,031 outpatients of Kanazawa University Hospital. Chest radiographs were taken with the FCR 9501 ES system, with patients upright. We studied the clinical efficacy of this diagnostic method. The method and usage procedures involved have been sufficiently technologically refined to permit handling of an adequate number of patients in a reasonable time at a permissible exposure dose. However, the system can be further improved technologically in order to obtain fully consistent high-quality images, regardless of the patient's physique. For well-rounded image reading, three kinds of images must be generated simultaneously: an original image; soft tissue (bone subtracted image) and bone (soft tissue subtracted image) Some soft tissue image were helpful for detecting non-calcified parenchymal nodules that overlapped the rib shadow, and some bone image served to precisely diagnose the existence of abnormal ribs, calcified lymph nodes, and calcified nodules. Furthermore, the bone images were helpful for revealing that the fine infiltrative shadows in the lung fields in original images were actually pleural calcifications and that the poorly defined nodular opacities were, in reality, abnormal rib calcifications. In light of the above, we wish to stress the importance of clinical efficacy of not only soft tissue images but bone images derived using the energy subtraction method. The clinical usefulness of this method was confirmed in 66 of 1,031 patients (6.4%) who had initially been scheduled for routine chest radiography. This result indicates how frequently the method encounters applicable cases when applied non-selectively to general patients who require radiographic chest examination. The advantages of this method will become much more evident with an examination protocol that minimizes unnecessary special examinations or optimizes the balance between screening and special examinations.     

Measurement of absolute lung volumes by imaging techniques

In this paper, the techniques available for estimating total lung capacities from standard chest radiographs in children and infants as well as adults are reviewed. These techniques include manual measurements using ellipsoid and planimetry techniques as well as computerized systems. Techniques are also available for making radiographic lung volume measurements from portable chest radiographs. There are inadequate data in the literature to support recommending one specific technique over another. Though measurements of lung volumes by radiographic, plethysmographic, gas dilution or washout techniques result in remarkably similar mean results when groups of normal subjects are tested, in patients with disease, the results of these different basic measurement techniques can differ significantly. Computed tomographic and magnetic resonance techniques can also be used to measure absolute lung volumes and offer the theoretical advantages that the results in individual subjects are less affected by variances of thoracic shape than are measurements made using conventional chest radiographs.     

Junctional tachycardia during radiofrequency ablation of the slow pathway in patients with AV nodal reentrant tachycardia: effects of autonomic blockade

BACKGROUND: Exogenous surfactant treatment of hyaline membrane disease is known to modify the pattern of radiological changes on the chest radiograph. OBJECTIVES: To analyse and attempt to explain the radiological changes observed after exogenous surfactant treatment. Materials and methods. Thirty-nine premature infants with typical hyaline membrane disease. RESULTS: Transient asymmetrical clearing with better aeration of the right lung in the absence of malposition of the tip of the endotracheal tube was observed in nine cases (23 %). This asymmetry was patchy in one case. It was due to a complication of mechanical ventilation in three cases [pneumothorax (n = 2) and pneumomediastinum (n = 1)]. In the other six cases, asymmetrical clearing could be related to the anatomical position of the right main bronchus, which facilitates distribution of surfactant to the right lung. However, the course of these premature infants was similar to that of infants with symmetrical chest radiological findings after treatment. CONCLUSIONS: Asymmetrical clearing of chest radiographs, sometimes patchy, after surfactant treatment requires exclusion of pneumothorax or infection but has no influence on clinical outcome.     

Systemic arterial supply to normal basal segments of the left lung: characteristic features on chest radiography and CT

OBJECTIVE: The purpose of this report is to present the characteristic features on chest radiography and CT of systemic arterial supply to normal basal segments of the left lung in three cases. CONCLUSION: Accurate interpretation of chest radiographs and CT scans is important in making the correct diagnosis and avoiding life-threatening lung biopsy.     

Characterization of protein kinase C-mediated phosphorylation of the short cytoplasmic domain isoform of C-CAM

BACKGROUND: Picture Archiving Communication System (PACS) is a sophisticated software and hardware package that enables clinicians to retrieve, review, and digitally manipulate radiographs from computer workstations throughout the hospital. PACS was instituted at Brooke Army Medical Center in July 1993. METHODS: Fifty consecutive trauma and 50 consecutive motor vehicle crash (MVC) trauma admissions to an urban trauma center were reviewed before PACS (January 1993) and 18 months after PACS was instituted (January 1995). Patients were compared by the number of radiographs needed during the initial evaluation by type and total. The trauma groups were subdivided by mechanism and also compared. Demographic and physiologic data were collected for each patient. RESULTS: There are no differences in the demographic and physiologic data between groups. For the 50 consecutive trauma admissions, only two areas of statistical difference were found: more chest films were obtained in the MVC PACS group and more pelvis films were obtained in the gunshot wound pre-PACS group. For the 50 consecutive MVC trauma admissions, the PACS group had more chest and total radiographs per patient than the pre-PACS group. More computed tomographic scans of the neck were obtained in the PACS group. CONCLUSION: PACS did not decrease the number of radiographs needed to adequately and fully evaluate the trauma patient.     

Personal computer teleradiology interhospital image transmission to facilitate tertiary pediatric telephone consultation and patient transfer: soft-tissue lateral neck and elbow radiographs

Although teleradiology systems are available commercially, they are expensive ($30,000), and different makes are incompatible with each other, making them unusable for interhospital image transfers. Standard components were added to a personal computer (PC) to build a functional teleradiology unit capable of interhospital image transmission at a low cost ($600 upgrade). This PC teleradiology system was studied to assess its accuracy in the interpretation of soft-tissue lateral neck x-rays with epiglottitis or retropharyngeal abscesses and elbow x-rays with joint effusions, fractures, or both. A radiologist and a pediatric emergency physician were asked to read the PC teleradiology images. Both physicians read 13 of 13 soft-tissue lateral neck x-rays and 15 of 15 elbow x-rays correctly. This study supports the premise that PC teleradiology can be used to facilitate telephone consultation and patient transfers between tertiary pediatric emergency centers by transmitting pertinent radiographic information over a phone line. Although verbal communication can often suffice in a telephone consultation or transfer, there are many instances when visualizing a radiographic image such as an x-ray or computed tomography scan can provide important information that cannot be optimally described verbally. Rural hospitals can form interhospital image transmission links with tertiary center resources. Tertiary centers may elect to organize interhospital image transmission and referral networks with their rural hospital sources.     

A cryptologic based trust center for medical images

OBJECTIVE: To investigate practical solutions that can integrate cryptographic techniques and picture archiving and communication systems (PACS) to improve the security of medical images. DESIGN: The PACS at the University of California San Francisco Medical Center consolidate images and associated data from various scanners into a centralized data archive and transmit them to remote display stations for review and consultation purposes. The purpose of this study is to investigate the model of a digital trust center that integrates cryptographic algorithms and protocols seamlessly into such a digital radiology environment to improve the security of medical images. MEASUREMENTS: The timing performance of encryption, decryption, and transmission of the cryptographic protocols over 81 volumetric PACS datasets has been measured. Lossless data compression is also applied before the encryption. The transmission performance is measured against three types of networks of different bandwidths: narrow-band Integrated Services Digital Network, Ethernet, and OC-3c Asynchronous Transfer Mode. RESULTS: The proposed digital trust center provides a cryptosystem solution to protect the confidentiality and to determine the authenticity of digital images in hospitals. The results of this study indicate that diagnostic images such as x-rays and magnetic resonance images could be routinely encrypted in PACS. However, applying encryption in teleradiology and PACS is a tradeoff between communications performance and security measures. CONCLUSION: Many people are uncertain about how to integrate cryptographic algorithms coherently into existing operations of the clinical enterprise. This paper describes a centralized cryptosystem architecture to ensure image data authenticity in a digital radiology department. The system performance has been evaluated in a hospital-integrated PACS environment.     

Benzophenanthridine alkaloids of Chelidonium majus; II. Potent inhibitory action against the growth of human keratinocytes

OBJECTIVE: To determine whether the neonatal chest radiograph (CXR) at 28 days in very low birthweight (VLBW) infants who develop chronic neonatal lung disease (CNLD) predicts oxygen therapy duration or CXR abnormalities in early childhood. Also, to assess the inter-observer reliability of the radiologists scoring the CXR. METHODOLOGY: Clinically well survivors of CNLD (n = 46) had neonatal CXR scored (mean age 28.5 days) and compared with current CXR (mean age 40 months). The CXR were scored independently and 'blindly' by two paediatric radiologists using a standardized scoring system (range 0-10). RESULTS: There was no correlation between neonatal CXR scores and current CXR scores for either radiologist. There was no association between CXR severity scores and duration of oxygen therapy for either neonatal or current CXR. Radiologist A scored the current CXR significantly more abnormal than radiologist B [medians (range): 3 (1-6) vs 1 (0-5), P < 0.001] with reasonable correlation (r = 0.593, P < 0.005) but worse than chance agreement (kappa = -0.034). The median scores for the neonatal CXR were similar [1.5 (0-8) vs 2 (0-8), P = 0.789] and again there was good correlation (r = 0.760, P < 0.0005) although poor individual agreement (kappa = 0.243) between radiologists. CONCLUSIONS: Follow-up CXR abnormalities in VLBW infants with CNLD are usually minor and are not predictive of the duration of oxygen therapy that will be required nor of the CXR appearance in early childhood. Considerable inter-observer variation exists in the interpretation of the CXR in CNLD.     

Measurement of scatter fractions in erect posteroanterior and lateral chest radiography

Scatter fractions (SFs) measured in patients undergoing erect posteroanterior (PA) and lateral chest radiography with a 12:1 antiscatter grid are reported. Modifications to the posterior beam-stop (PBS) technique allowed measurement of scatter in these patients, without altering the diagnostic image and without additional radiation exposure. The SF measurements are reported by anatomic location on 42 clinical chest images. Average SF values ranged from 0.27 to 0.90 on lateral radiographs and from 0.27 to 0.68 on PA radiographs. Scatter measurements with the 12:1 grid were found to be greater than estimates from previous PA chest phantom experiments. To the authors' knowledge, they were the first to measure radiation scatter with the PBS technique in patients undergoing PA and lateral chest radiography with the antiscatter grid.     

Advanced multiple beam equalization radiography (AMBER) combined with computed radiography. Preliminary evaluation

The combined use of AMBER (Advanced Multiple Beam Equalization Radiography) and a digital storage phosphor (SP) radiography system was evaluated for chest radiography in a pilot study with 4 patients. Four image modes with different dose levels were compared: the SP in combination with an AMBER equalized exposure (SP/AMBER) and 3 nonequalized exposures with dose levels corresponding to the respective calculated AMBER lung dose (SP/lung field dose), the calculated AMBER mediastinal dose (SP/mediastinal dose) and the calculated AMBER average dose (SP/average dose). All image modes were matched for Hurter and Driffield characteristics and subjectively rated according to visibility of details. The improved signal-to-noise (S/N) ratio of SP/AMBER resulted in a better visualization of structures in the mediastinum and the basal lung where SP/lung field dose scored lowest. For the central lung no quality differences were seen between techniques. The compressed dynamic range of the SP/AMBER images was more easily displayed on the hard-copy film. The combination of AMBER with SP radiography promises to overcome the dynamic range limitations of digital displays while, at moderate doses, giving better S/N and image quality than standard SP technique.     

Influence of neuronal excitation and inhibition of rostral ventrolateral medulla on the effect of electroacupuncture of "Neiguan" acupoint]

OBJECTIVES: To evaluate observers' use of image-enhancement facilities and time consumption in assessing caries in radiographs taken with four digital systems. METHODS: In total, 131 extracted human premolars and molars were mounted three in a line. Radiographs were taken using four digital systems: Digora (DIG), Radio VisioGraphy (RVG), Sens-A-Ray (SAR) and Visualix (VIX), and imported into a programme with routines for adjustment of brightness, contrast and gamma curve. Sixteen images from each digital system were compressed (JPEG, irreversible compression). The 588 images were scored by six observers for approximal and occlusal caries on a five-point confidence scale using enhancement as they pleased. The programme automatically recorded any enhancement made without the observers knowing this. RESULTS: Some form of digital enhancement was used in almost all images, with the gamma curve being the most frequent. The VIX images were enhanced most followed by SAR, DIG and RVG images. The differences were significant (p < 0.01) except between DIG and SAR images. The compressed images were enhanced significantly more than their uncompressed counterparts (p = 0.02). The average time spent recording one image was 24 s. On average, significantly less time was spent with the DIG images than the other systems (p < 0.01), while there were no significant differences between the CCD-based systems (p > 0.2). There was no relationship between time spent and number of manipulations performed. CONCLUSIONS: The observers took advantage of the facilities available for enhancement of density and contrast in digital images. The potential of gamma curve manipulation requires further investigation.     

Mottle on computed radiographs of the chest in pediatric patients

PURPOSE: To investigate the relationship between radiation exposure and perceived mottle at bedside pediatric chest examinations performed with screen-film and computed radiographic techniques. MATERIALS AND METHODS: In a pediatric intensive care unit, chest radiographs were obtained with both computed radiography (60 radiographs) and a 600-speed screen-film system (14 radiographs). The relative radiation exposure was estimated by using the sensitivity value obtained in the processing of each computed radiograph. Five radiologists assessed the mottle present in the computed radiographs and screen-film images. RESULTS: For computed radiographs, the perceived level of mottle was inversely related to radiation exposure. For the same radiation exposure, the perceived mottle on computed radiographs was significantly higher than that on screen-film images (P < .001 for small cassettes; P < .01 for large cassettes). CONCLUSION: Pediatric computed radiography of the chest requires approximately twice the exposure of a 600-speed screen-film system to attain the same level of mottle.     

Variability in the classification of radiographs using the 1980 International Labor Organization Classification for Pneumoconioses

This study describes the extent of agreement in classification of chest radiographs using the International Labor Organization (ILO) classification among six readers from the United States and Canada. A set of 119 radiographs was created and read by three Canadian and three US readers. The two ratings of interest were profusion (scored from 0/- to 3/+) and pleural abnormalities consistent with pneumoconiosis (scored with the ILO system, then collapsed into a yes/no). We used a number of approaches to evaluate interreader agreement on profusion and pleural changes, determining concordance, observed agreement, kappa statistic, and a new measure to approximate sensitivity and specificity. This study found that five of six readers had good fair to good agreement for pleural findings and for profusion as a dichotomous variable (> or = 1/0 vs < or = 0/1) using the kappa statistic, while a sixth reader had poor agreement. We found that concordance, expressed as percent agreement, was higher for normal radiographs than for ones that showed disease, and describe the use of the kappa statistic to control for this finding. This analysis adds to the existing literature with the use of the kappa statistic, and by presenting a new measure for "underreading" and "overreading" tendencies.