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Biomedical subjects

S Don

Publications and source records attributed to S Don.

At least 19 recordsLinked to original sources
PubMed2000

Conversion to soft-copy sonography: effects on imaging time and costs.

OBJECTIVE: To determine the effect of conversion to soft-copy interpretation on the number of images and imaging time. MATERIALS AND METHODS: Before and 1 year after conversion to soft-copy interpretation, 20 consecutive normal abdominal, renal, and cranial sonograms were performed by each of three technologists (360 sonograms total). The number of images and imaging time per sonogram were recorded. For each technologist and each examination type, the differences between number of images and the imaging times before and after conversion were compared. Multivariate repeated measures analysis of variance was used to analyze the data. RESULTS: After conversion to soft-copy, the number of images significantly increased for all imaging types (P = 0.004), and the imaging time significantly decreased (P < 0.001). After conversion, there were 213 more images. The average number of images increased 1.0 per abdominal sonogram, 0.5 per renal sonogram, and 2.0 per cranial sonogram. The additional storage requirement for the 213 images was 64 MB; total long-term storage media cost increased $1.06. On average, there was a 19% decrease in imaging time, with abdominal imaging time decreasing 2 min and 18 s, renal 1 min and 46 s, and cranial 40 s. This would potentially allow time for two additional sonograms to be performed per day and would generate up to $112,000 additional revenue per year. CONCLUSION: Following soft-copy conversion, there was a significant increase in the number of images acquired per examination, with an increased storage requirement but a negligible increase in storage cost. Technologist efficiency significantly improved.

Abdomen↗
PubMed1999

Computed radiography versus screen-film radiography: detection of pulmonary edema in a rabbit model that simulates neonatal pulmonary infiltrates.

PURPOSE: To determine if computed radiography is equivalent to screen-film radiography in depicting pulmonary edema and to determine if radiation exposure can be reduced with computed radiography while maintaining equivalent diagnostic accuracy for pulmonary edema. MATERIALS AND METHODS: Oleic acid was intravenously injected into three rabbits at each of four doses: 0, 0.02, 0.04, and 0.06 mL/kg. Two hours later, chest computed radiographs and screen-film radiographs were obtained at 60 kVp and 1.1 mAs. Additional computed radiographs were obtained after reducing milliampere seconds or by reducing milliampere seconds and increasing the kilovolt peak, which reduced bone marrow exposure by up to 20%. The presence of pulmonary opacities, "truth," was established by the wet-dry weight ratio and by chest computed tomography (CT). The radiographs were masked and randomized. Four observers rated the images for the presence of parenchymal opacities with a dichotomous score and judged the quality of the radiographs on a scale from 1 (worst) to 6 (best). Cochran Q tests and McNemar tests were used to analyze the differences in paired comparisons. Image quality was evaluated with logistic regression analysis. RESULTS: There was no significant difference between truth and observer ability to detect opacity for either modality or for any exposure (P > .05). There was no significant difference between computed radiography and screen-film radiography for image quality (P > .05). CONCLUSION: Computed radiography is equivalent to screen-film radiography in the detection of pulmonary edema. Radiation exposure reduction of 20% can be achieved without affecting pulmonary edema detection or image quality.

Animals↗
PubMed1999

Soft-copy versus hard-copy interpretation of voiding cystourethrography in neonates, infants, and children.

OBJECTIVE: Our aim is to determine whether agreement occurs between soft-copy (at a review workstation) and hard-copy (on laser-printed film) interpretations of fluoroscopic voiding cystourethrograms in neonates, infants, and children. SUBJECTS AND METHODS: Voiding cystourethrography was performed on 74 children (range, 2 weeks to 11 years old; mean, 3 years 6 months) for the evaluation of vesicoureteral reflux. The right and left ureters were scored separately by two observers on a scale of 0-5 using the international grading standard. Differences were tested for statistical significance with a marginal homogeneity test, and the strength of agreement was assessed using the kappa statistic. RESULTS: Of the 148 ureters evaluated, 39 showed vesicoureteral reflux and 109 showed no vesicoureteral reflux on both soft copy and hard copy. For 128 of 148 evaluations, interpretations of soft copy and hard copy produced agreement as to the grade of vesicoureteral reflux. For 11 of the 20 ureters with divergent interpretations, hard copy was scored one grade lower than soft copy; for the remaining nine ureters, hard copy was scored one grade higher than soft copy. No score differed by more than one grade. We found no statistically significant difference between soft-copy and hard-copy scores (p = .65), and agreement using the kappa statistic was substantial (.68). CONCLUSION: Soft-copy interpretation of voiding cystourethrograms is similar to hard-copy interpretation for vesicoureteral reflux.

Child↗
PubMed1998

Sensitivity and cost minimization analysis of radiology versus olive palpation for the diagnosis of hypertrophic pyloric stenosis.

BACKGROUND/PURPOSE: Two strategies are commonly used for the initial diagnosis of hypertrophic pyloric stenosis (HPS): (1) physical examination and (2) radiologic evaluation using upper gastrointestinal series (UGI) or sonography. The authors wished to determine the sensitivity and relative cost of each strategy. METHODS: The charts of 234 patients presenting over 3 years with a history suggestive of HPS were reviewed retrospectively. Cost, expressed as mean diagnostic charges (MDC) and mean total charges (MTC), was calculated according to two theoretical models. In model A, all patients first are examined by a surgeon. If an olive is palpable, they proceed to surgery. If not, they are sent to radiology. In model B, all patients have radiologic investigation first, and then surgical evaluation if the study result is positive. RESULTS: Of the 234 patients, 150 had HPS (64%). Olives were appreciated in 111 of these (palpation sensitivity of 74%). There was one false-positive olive (0.7%) and no false-negatives. Sonography and UGI were equally accurate (sensitivity of 100%, 0.5% false-positive). Equations were generated to estimate MDC and MTC for our patient population under each model. In model A, MDC = $507 - ($221 x palpation sensitivity) and MTC = $2,543 ($240 x palpation sensitivity). In model B, MDC = $449 and MTC = $2,454, and costs were independent of ability to feel an olive. When cost was plotted against palpation sensitivity, model A yielded a lower MDC than model B if palpation sensitivity was at least 26%, and a lower MTC if palpation sensitivity was at least 37%. Because our palpation sensitivity was 74%, approximately $100 per patient would be saved by sending all infants suspected of having HPS to a surgeon for examination as an initial step. CONCLUSIONS: Although highly sensitive, imaging is superfluous if an olive is palpable. Children suspected of having HPS should have a surgical consultation before a radiology study as long as the surgeon's palpation sensitivity for an olive is at least 37%. Improved palpation skills will result in maximum financial savings.

Costs and Cost Analysis↗
PubMed1998

Soft-copy sonography: cost reduction sensitivity analysis in a pediatric hospital.

OBJECTIVE: Our objective was to determine whether interpreting sonograms of pediatric patients using soft-copy (computer workstation) instead of laser-printed film could reduce costs for a pediatric radiology department. We used theoretic models of growth to analyze costs. MATERIALS AND METHODS: The costs of a sonographic picture archiving and communication system (three interface devices, two workstations, a network server, maintenance expenses, and storage media costs) were compared with the potential savings of eliminating film and increasing technologist efficiency or reducing the number of technologists. The model was based on historic trends and future capitation estimates that will reduce fee-for-service reimbursement. The effects of varying the study volume and reducing technologists' work hours were analyzed. RESULTS: By converting to soft-copy interpretation, we saved 6 min 32 sec per examination by eliminating film processing waiting time, thus reducing examination time from 30 min to 24 min. During an average day of 27 examinations, 176 min were saved. However, 33 min a day were spent retrieving prior studies from long-term storage; thus, 143 extra minutes a day were available for scanning. This improved efficiency could result in five more sonograms a day obtained by converting to soft-copy interpretation, using existing staff and equipment. Alternatively, five examinations a day would equate to one half of a full-time equivalent technologists position. Our analysis of costs considered that the hospital's anticipated growth of sonography and the depreciation of equipment during 5 years resulted in a savings of more than $606,000. Increasing the examinations by just 200 sonograms in the first year and no further growth resulted in a savings of more than $96,000. If the number of sonograms stayed constant, elimination of film printing alone resulted in a loss of approximately $157,000; reduction of one half of a full-time equivalent technologist's position would recuperate approximately $134,000 of that loss. CONCLUSION: Soft-copy sonography can save money through improved technologist efficiency, thereby increasing the number of sonograms obtained and revenue generated. If the number of sonograms does not increase, elimination of printing costs and reduction of staff technologists will not result in a savings.

Cost Savings↗
PubMed1998

Skeletal surveys for child abuse: comparison of interpretation using digitized images and screen-film radiographs.

OBJECTIVE: The objective of our study was to compare child abuse detection using screen-film radiographs and their digitized images displayed on a computer workstation. MATERIALS AND METHODS: Skeletal surveys of 20 consecutive child abuse patients whose abuse was clinically proven by a combination of history, physical and radiographic findings, and social work history, and 20 consecutive control subjects were evaluated. Three radiologists rated both the screen-film radiographs (400-speed, double-emulsion film) and their digitized images displayed on a workstation (2K x 2K resolution) using a six-point ordinal scale for suspicion of child abuse, fracture detection, and image quality. The rating response was analyzed using multiobserver-multicase receiver operating characteristic analysis of variance. The McNemar test was used to evaluate differences between imaging techniques and between diagnoses made using each imaging technique and clinically proven child abuse. RESULTS: The area under the receiver operating characteristic curve for screen-film radiographs was 0.934+/-0.025 and for digitized images was 0.922+/-0.013. This difference was not significant (p = .658); however, two observers significantly underestimated the child abuse diagnosis with digitized images (p = .02). In a review of the false-negative child abuse diagnoses, observers failed to recognize characteristic metaphyseal fractures (10 observations) and rib fractures (five observations) on digitized images that had been recognized on screen-film radiographs. Mean image quality was rated significantly lower (p < .0001) and interpretation time was significantly longer (75 sec; p < .001) for the digitized images than for screen-film radiographs. CONCLUSION: The characteristic types of fractures that were not identified on the digitized images, lower image quality, and longer interpretation time raise concern that digitized images may not be adequate for interpretation of suspected child abuse.

Bone and Bones↗
PubMed1997

Soft-copy versus hard-copy cranial sonography: intraobserver agreement and workstation efficiency.

OBJECTIVE: The objective of the study was to determine the intraobserver agreement, confidence level, and efficiency in interpretation of soft-copy (workstation) versus hard-copy (laser-printed film) sonograms of the cranium. MATERIALS AND METHODS: Cranial sonograms of 100 premature infants were randomly reviewed twice on both soft-copy and hard-copy images by three observers and were graded for hemorrhage using a five-level scale. The kappa statistic was calculated to measure intraobserver agreement. Differences in agreement were tested for statistical significance with a test for marginal homogeneity. Observers rated their confidence in interpretation using a six-point ordinal scale. Total viewing time was recorded, and videotaped sessions were analyzed for image handling time (opening each case, closing each case, and selecting the next case) and interpretation time. RESULTS: For soft copy versus hard copy, the mean kappa value was .73; for hard-copy 1 versus hard-copy 2, .71; and for soft-copy 1 versus soft-copy 2, .65. None of these differences was statistically significant (p > .05). The mean confidence score was the same for soft copy (5.3) and hard copy (5.3). On average, the observers needed 24 min longer to review 100 studies on soft copy than on hard copy. Opening and closing times for soft copy were significantly faster than for hard copy (p = .0001); however, case selection for soft copy, which was not needed for hard copy, took 4.69-9.09 sec per case. Extrapolated to 100 cases, case selection accounted for 8-15 min of viewing time. CONCLUSION: Radiologist agreement and confidence in the interpretation of cranial sonograms for hemorrhage was the same for soft copy and hard copy. However, viewing times were longer for soft copy. Elimination of inefficiency in case selection could improve image-handling time.

Cerebral Hemorrhage↗
PubMed1996

Perflubron as a gastrointestinal MR imaging contrast agent in the pediatric population.

OBJECTIVE: To evaluate the safety and efficacy of orally administered perflubron for bowel recognition on MR imaging in a pediatric population. MATERIALS AND METHODS: A multicenter trial evaluated 39 pediatric subjects before and after ingestion of perflubron with T1-, proton-density, and T2-weighted sequences through the abdomen and/or pelvis. Post-contrast images were compared with pre-contrast images. Safety was evaluated through assessment of adverse events, clinical laboratory parameters, and vital signs. RESULTS: With regard to efficacy analysis, improvement in the percent of bowel darkened was observed for 85 % of the subjects on T1-weighted images and for 95 % of the subjects on proton-density and T2-weighted images. For images of the abdominal region, the percent of bowel darkened was improved for 90-92 % of the subjects across pulse sequences. Improvement rates for the images of the pelvic region ranged from 71 % to 100 %. For at least 75 % of the subjects, proton-density and T2-weighted images of the body and tail of the pancreas, left lobe of the liver, mesenteric fat, and pathological tissue were improved relative to predosing images. Twenty-three percent of the subjects experienced some adverse effects, most of which were minor and related to the digestive system. Clinical laboratory and vital sign evaluations revealed no trends associated with the administration of perflubron. CONCLUSION: Perflubron is a relatively safe and effective gastrointestinal MR contrast agent in the pediatric population.

Abdomen↗
PubMed1996

Ghosting of pulmonary nodules with respiratory motion: comparison of helical and conventional CT using an in vitro pediatric model.

OBJECTIVE: The study was designed to compare helical CT with varying pitch and reconstruction intervals and conventional CT for revealing pulmonary nodules in a model that simulates respiratory motion in children. MATERIALS AND METHODS: CT scans were obtained in an experimental model with one nodule (3 or 10 mm) in each scan. One-second scans were obtained at rates of 10, 20, and 30 respirations per minute using conventional CT with 4-mm collimation and table incrementation and helical CT with 4-mm collimation and either 4-mm/sec (pitch, 1:1) or 8-mm/sec (pitch, 2:1) table speed. Reconstructions were at 1-, 2-, and 4-mm intervals for scans obtained using 4-mm/sec table speed and at 1- and 4-mm intervals for scans obtained using 8-mm/sec table speed. Images were independently reviewed by three radiologists who estimated the number of nodules on each image. RESULTS: Ghosting (depiction of more than one nodule in a study) was seen in 79%, 80%, and 75% of helical CT scans obtained with a 1:1 pitch using 1-, 2-, and 4-mm reconstruction intervals, respectively. By comparison, ghosting was seen in only 54% and 58% of helical CT scans with a 2:1 pitch using 1-mm reconstruction intervals and 4-mm reconstruction intervals, respectively, and in 56% of conventional CT scans (p < .0001). A single nodule was detected on all other scans, and at least one nodule was seen on all scans. CONCLUSION: Ghosting of nodules is common in this model. Ghosting was seen less often on conventional scans and helical scans with 2:1 pitch than it was on helical scans with 1:1 pitch. Nonetheless, ghosting was seen on more than 50% of all scans with each technique.

Artifacts↗
PubMed1995

Volume detection threshold: quantitative comparison of computed radiography and screen-film radiography in detection of pneumothoraces in an animal model that simulates the neonate.

PURPOSE: To quantitatively compare computed radiography (CR) and screen-film radiography (SFR) in the detection of pneumothorax in an animal model that simulates the neonate. MATERIALS AND METHODS: Three rabbits underwent placement of 5-F catheters in the right pleural space. Eight CR and eight SFR images were obtained. Volume-controlled pneumothorax was induced by incrementally injecting 4 cm3 of air (24 cm3 total) and four CR and four SFR images were obtained after each injection. Four radiologists blindly viewed the images twice (eight readings per image, 1,600 total observations). A dichotomous yes-no score for the presence of pneumothorax was used to calculate the volume detection threshold (VDT), defined as the air volume at which 50% of the pneumothoraces can be detected. The authors plotted the likelihood of a pneumothorax against the air volume by using the confidence indicator. RESULTS: Intraobserver VDT values for CR and SFR were not significantly different. CONCLUSION: CR is as accurate as SFR in the detection of pneumothorax in this quantitative animal model.

Animals↗
PubMed1995

Soft-copy computed radiography in neonatal and pediatric intensive care units: cost-savings analysis.

PURPOSE: To determine whether soft-copy interpretation of computed radiography (CR) in neonatal and pediatric intensive care units (ICUs) can result in a cost savings compared with screen-film radiography for the radiology department. MATERIALS AND METHODS: The actual cost of CR equipment, maintenance contracts, and the estimated cost for data storage were compared with the potential savings that could result from eliminating film, decreasing the number of librarians and lost radiographs, and improving technologists' efficiency. RESULTS: After the 1st year, net cash flow from use of soft-copy CR interpretation is projected to result in a slight savings for the radiology department but not enough to offset the capital equipment purchase price. CONCLUSION: Soft-copy CR ICU imaging will not result in a cost savings. To have a balanced net cash flow would require either more than doubling potential savings or decreasing capital equipment cost by greater than one-half. The justification for soft-copy CR needs to be judged by its effect on increasing physician efficiency and timely decisions on patient care.

Capital Financing↗
PubMed1994

Ultrasound-guided pediatric liver transplant biopsy using a spring-propelled cutting needle (biopsy gun).

Biopsy is the best way to diagnose allograft rejection, the most common complication following liver transplantation. The authors reviewed 99 consecutive ultrasound-guided cutting needle biopsies in 19 infants and children. Conscious sedation was used with 95 biopsies. General anesthesia was used with four biopsies, all in patients undergoing percutaneous biliary procedures at the same time. Ninety-eight biopsies were diagnostic. Only one major complication occurred: biloma. Ultrasound-guided cutting needle biopsy of pediatric liver transplant patients can be performed safely and efficaciously.

Biopsy, Needle↗
PubMed1994

Mediation of the trophic effects of short-chain fatty acids on the rat jejunum and colon.

BACKGROUND/AIMS: Short-chain fatty acids (SCFAs) are trophic to small intestinal and colonic mucosa. This study determined whether SCFAs infused into the cecum out of continuity stimulated jejunal and colonic cellularity and whether these effects were mediated by the autonomic nervous system and/or enterotrophic hormones. METHODS: To eliminate direct trophic effects of SCFAs in contact with mucosa, 60 rats underwent cecal isolation with placement of an infusion catheter into the proximal cecum, formation of distal cecocutaneous stoma, and restoration of intestinal continuity with ileocolonic anastomosis. Rats underwent cecal denervation or remained normally innervated and received 1 of 3 infusions for 10 days: SCFAs, saline, or no infusion. Twenty-four additional rats were assigned to the same groups but underwent infusion into the proximal colon (in circuit). RESULTS: Cecal infusion of SCFAs into innervated rats increased (P < 0.05) jejunal DNA, villous height, surface area, crypt depth, and gastrin without increasing colonic variables. In denervated rats, SCFAs did not significantly affect these variables. However, direct intracolonic infusions of SCFAs increased (P < 0.05) colonic mucosal DNA and crypt depth. CONCLUSIONS: Jejunotrophic effects of cecally infused SCFAs are mediated afferently by the autonomic nervous system and are associated with increased jejunal gastrin. SCFAs have local trophic effects on the colon.

Animals↗
PubMed1994

Rabbit pneumothorax. Feasibility of an animal model to simulate neonatal pneumothorax.

RATIONALE AND OBJECTIVES: The feasibility of developing an animal model to simulate radiographic features of neonatal pneumothorax was investigated, and supine computed radiography (CR) and film-screen radiography (FS) images were compared. METHODS: 5-Fr pigtail catheters were inserted into the right pleural space of three New Zealand white rabbits. Two CR and two FS supine images were obtained using identical technique. After serial 4-mL injections of air, one CR and one FS supine image were obtained. The images were masked and randomized, and four radiologists reviewed the images for typical signs of pneumothorax. Chest computed tomography (CT) was performed before the injection of any air and after completion of the study. RESULTS: At zero-mL air volume, radiologists did not perceive a pneumothorax. As the air volume increased, the number of signs of a pneumothorax increased; there was no significant difference between CR and FS in the number of signs of pneumothorax detected at any volume. Chest CT confirmed that there was no unexplained air leak. The volume of air injected correlated with the calculated volume from the CT. CONCLUSIONS: This induced, volume-controlled, animal model simulated the supine radiographic features of neonatal pneumothorax.

Animals↗
PubMed1992

Air reduction of an intussusception caused by a pathologic lead point in an infant.

Lead points that are the cause of an ileocolic intussusception are rare in infants [1], as is successful reduction using barium [2]. Air reduction of an intussusception with a pathologic lead point has not been previously reported. We report a case of an infant with an ileocolic intussusception secondary to a duplication cyst that was successfully reduced with air. The pathologic lead point was recognized at the time of reduction and confirmed with water-soluble contrast. Air is both a diagnostic and therapeutic contrast agent.

Air↗
PubMed1992

Selected topics in hepatobiliary imaging.

With the advent of ultrasound, computed tomography, and magnetic resonance imaging, hepatobiliary imaging is changing. The advantages and disadvantages of each new imaging modality will be reviewed. The radiographic approach of a child who presents with a mass or jaundice will be discussed. The role of duplex Doppler ultrasound in the preoperative and postoperative management of liver transplantation patients will be presented.

Biliary Tract Diseases↗
PubMed1990

CT cholangiography of a choledochocele.

Choledochocele is a rare anomaly which has been imaged by a variety of techniques, including CT. A case of choledochocele in an eleven-year-old boy is reported. CT demonstrated a fluid-filled lesion protruding into the lumen of the duodenum and containing stones. CT following oral cholangiogram contrast administration and intravenous sincalide confirmed connection of the cystic lesion with the biliary tree. This is a safe and noninvasive method for the diagnosis of choledochocele.

Child↗