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L R Kuhns

Publications and source records attributed to L R Kuhns.

At least 19 recordsLinked to original sources
PubMed2001

Use of computerized tomography and chest x-rays in evaluating efficacy of aerosolized recombinant human DNase in cystic fibrosis patients younger than age 5 years: a preliminary study.

The aim of this study was to evaluate the ability of high-resolution computerized tomography (HRCT) of the chest and chest x-rays (CXR) to determine efficacy of inhaled recombinant human DNase (rhDNase) in cystic fibrosis (CF) patients younger than 5 years of age. A randomized, double-blind, placebo-controlled pilot study of 12 patients with CF younger than 5 years of age, attending the University of Michigan Cystic Fibrosis Center (Ann Arbor, MI) was conducted. The changes in the HRCT and CXR score from baseline to day 100 of therapy were assessed using a previously validated scoring system. The mean changes of HRCT scores between the rhDNase and placebo groups were found to be significant at the 95% level, with mean change +/- SE mean of - 1.00 +/- 0.53 and 0.58 +/- 0.24 for rhDNase and placebo groups, respectively (P = 0.02). The difference in CXR score was not significant between the two groups. An analysis was performed to relate HRCT subscores to CXR score; only thickening of the intra-interlobular septae was significantly correlated with the total CXR score (r = - 0.7, P < 0.01). There was improvement in the parents' assessments of the patients' well-being, with improvement in physical activity, decreased cough, sleep quality, and appetite in those subjects receiving rhDNase. We conclude that the administration of rhDNase was associated with improvement in the HRCT scan in CF patients younger than 5 years of age. Findings indicate that HRCT of the chest is useful and sensitive in studying responses to therapy in patients with CF lung disease. To our knowledge, this is the first report of the use of HRCT to assess the effectiveness of a therapeutic modality in so young a CF patient population.

Administration, Inhalation↗
PubMed2001

Three quantitative approaches to the diagnosis of abdominal pain in children: practical applications of decision theory.

BACKGROUND/PURPOSE: The authors compared 3 quantitative methods for assisting clinicians in the differential diagnosis of abdominal pain in children, where the most common important endpoint is whether the patient has appendicitis. Pretest probability in different age and sex groups were determined to perform Bayesian analysis, binary logistic regression was used to determine which variables were statistically significantly likely to contribute to a diagnosis, and recursive partitioning was used to build decision trees with quantitative endpoints. METHODS: The records of all children (1,208) seen at a large urban emergency department (ED) with a chief complaint of abdominal pain were immediately reviewed retrospectively (24 to 72 hours after the encounter). Attempts were made to contact all the patients' families to determine an accurate final diagnosis. A total of 1,008 (83%) families were contacted. Data were analyzed by calculation of the posttest probability, recursive partitioning, and binary logistic regression. RESULTS: In all groups the most common diagnosis was abdominal pain (ICD-9 Code 789). After this, however, the order of the most common final diagnoses for abdominal pain varied significantly. The entire group had a pretest probability of appendicitis of 0.06. This varied with age and sex from 0.02 in boys 2 to 5 years old to 0.16 in boys older than 12 years. In boys age 5 to 12, recursive partitioning and binary logistic regression agreed on guarding and anorexia as important variables. Guarding and tenderness were important in girls age 5 to 12. In boys age greater than 12, both agreed on guarding and anorexia. Using sensitivities and specificities from the literature, computed tomography improved the posttest probability for the group from.06 to.33; ultrasound improved it from.06 to.48; and barium enema improved it from.06 to.58. CONCLUSIONS: Knowing the pretest probabilities in a specific population allows the physician to evaluate the likely diagnoses first. Other quantitative methods can help judge how much importance a certain criterion should have in the decision making and how much a particular test is likely to influence the probability of a correct diagnosis. It now should be possible to make these sophisticated quantitative methods readily available to clinicians via the computer.

Abdominal Pain↗
PubMed2000

Cervical spine standards for flexion radiograph interspinous distance ratios in children.

RATIONALE AND OBJECTIVES: The purpose of this study was to quantitate the interspinous distances in a group of children as they underwent flexion during lateral radiography. MATERIALS AND METHODS: The cases of 59 children with minor trauma who underwent lateral flexion radiography were studied retrospectively. Measurements of each cervical interspinous distance and anteroposterior diameter of the adjacent body were used to calculate a ratio of interspinous distance to vertebral body diameter at each level. Linear regression analyses of each ratio to patient age were performed, and means and standard deviations of the ratios at each level were calculated. RESULTS: The ratios did not correlate in a statistically significant manner at any level with age. Therefore, data from all 59 children were used to calculate the mean and standard deviation at each cervical level. Most children with severe ligamentous injury who were considered for fusion had interspinous ratios greater than 2 standard deviations above the mean for the control group. CONCLUSION: Standards for interspinous distances during flexion by children are presented. These standards may prove to be helpful in the evaluation of children for cervical ligamentous injury.

Adolescent↗
PubMed1999

Facet coverage in children on flexion lateral cervical radiographs.

STUDY DESIGN: This radiographic study was designed to attempt to develop standards of facet coverage (overlap) on lateral cervical radiographs during voluntary flexion. OBJECTIVE: To produce normative standards for minimum facet coverage in children. SUMMARY OF BACKGROUND DATA: Previous studies on normative standards of facet coverage have been performed only in adults. METHODS: Thirty-six children with minor trauma had lateral flexion-extension radiographs. A standard filming sequence was used in all. Facet joint overlap at each level was divided by the anteroposterior diameter of the upper adjacent cervical body at each level. RESULTS: On linear regression analysis, these ratios did not vary significantly with age at C2-C3 through C6-C7. Means and standard deviations were determined for C2-C7. CONCLUSIONS: These ratios may prove useful in evaluation of children with possible ligamentous injury.

Adolescent↗
PubMed1998

Head-wag autotomography of the upper cervical spine in infantile torticollis.

BACKGROUND: Infants with torticollis require evaluation of the entire cervical spine for vertebral anomalies as part of the work-up, but open-mouth views to assess occiput to C2 are difficult to obtain. OBJECTIVE: To evaluate a "head wag" autotomographic technique for the frontal projection of this region. MATERIALS AND METHODS: Twenty infants under one year of age were evaluated using this technique. RESULTS: Sixteen of 20 could be adequately evaluated using this simple, low-radiation-dose procedure. CONCLUSION: For infants with torticollis in whom vertebral anomalies need to be excluded, the "head wag" technique is useful.

Cervical Vertebrae↗
PubMed1997

Musculoskeletal computed radiography in children: scatter reduction and improvement in bony trabecular sharpness using air gap placement of the imaging plate.

The effect of various air gaps on computed radiographic musculoskeletal images was investigated using a knee phantom. Scatter to primary radiation ratios were measured using the beam stop method at air gaps ranging from 0 to 30 in. (0-762-mm). Bony trabecular sharpness, line pair resolution, quantum mottle and visualization of low-contrast beads in the soft tissues were evaluated. A significant reduction of scatter to primary radiation ratio, from a value of almost 1 at table top to about 0.4 at 10-in. (254-mm) air gap and about 0.2 at 25-in. (635-mm) air gap placement of the computed radiography (CR) imaging plate, was obtained. A progressive improvement in bony trabecular sharpness and line pair resolution, compared with the table top and Bucky images was observed on 10-in. (254-mm) through 25-in. (635-mm) air gap images. Sharpness of the bony trabeculae and line pair resolution were best on the 25-in. (635-mm) air gap images. The skin entrance radiation dose does not have to be increased for air gap digital radiography. The radiographic noise or quantum mottle is highest on the Bucky image, higher on air gap images and minimal on the table top images, despite a high scatter to primary radiation ratio at the table top. The lower quantum mottle on the table top images allowed for maximal visualization of low contrast densities in the soft tissues. Air gap radiography further improves musculoskeletal computed imaging by reducing the scatter to primary radiation ratio without an increase in the skin entrance dose. For significant reduction of the scatter to primary radiation ratio and best evaluation of line pair spatial resolution and bony trabeculae, a 25-in. (635-mm) air gap with digital radiography would be optimal. For evaluation of low contrast densities in the soft tissues, table top placement would be the technique of choice.

Air↗
PubMed1997

Pediatric musculoskeletal computed radiography.

BACKGROUND: In conventional radiography, a film-screen system serves as the X-ray detector and the film also functions as an archival and display medium. Unlike film-screen radiography, these functions are uncoupled in computed radiography (CR). CR uses conventional radiographic equipment to expose an image on a storage phosphor plate instead of a film-screen combination. OBJECTIVE: To review the basic concepts of CR and to provide a background for discussion of specific musculoskeletal applications of CR in children. MATERIALS AND METHODS: Various aspects of musculoskeletal CR in children are presented based on our 4 years' experience and a review of the literature. RESULTS: A greater amount of scatter capture occurs with storage phosphor CR than with a film-screen system in the 70- to 120-kVp range. This is attributed to a lower K-absorption edge of barium in the barium fluorohalide (BaFBr) compound used in the imaging plate. A significant reduction of scatter to primary radiation, improvement in bony trabecular sharpness, and improvement in line pair resolution can be achieved in pediatric musculoskeletal imaging using an air gap without an increase in the skin entrance dose as compared to the non-grid table top technique. With CR, in addition to proper radiographic exposure technique, one needs to preprogram and select the optimal processing technique for each anatomic region, projection and age group of the child. CONCLUSION: The main advantages of CR in pediatric musculoskeletal imaging consist of a reduction in radiation dose for many applications, improved contrast resolution, near elimination of repeat radiographs related to exposure errors, and digital processing capabilities for image enhancement, storage, retrieval, display and transmission. The current limitations of CR include the moderately high start-up cost, the long learning curve to produce optimal films, and the reduced spatial resolution.

Artifacts↗
PubMed1995

Pediatric air-gap chest digital imaging: an experimental study.

Geometrically magnified computed radiography (CR) chest radiographs can be obtained in children using the same techniques as for non-grid, non-magnified CR radiographs. The resulting magnification images have less scatter than grid images and better line pair resolution.

Adolescent↗
PubMed1993

Optimal timing of abdominal CT in children: relationship to injection rate.

PURPOSE: To study computed tomographic (CT) scanning technique in relationship to rate of injection of contrast material for imaging of the liver and other abdominal organs in pediatric patients. MATERIALS AND METHODS: The time from start of injection of 2 mL/kg iohexol to peak opacification in the aorta, hepatic vein, liver, and kidney was determined for injection rates of 0-0.99, 1.00-1.99, 2.00-2.99, 3.00-3.99, and 4.00 mL/kg or more per minute in 77 pediatric patients. RESULTS: Peak liver opacification varied only slightly with different injection rates, but the time from start of injection to peak opacification in the aorta, hepatic vein, liver, and kidney did vary with injection rate. CONCLUSION: Data provided by this study should allow CT scanning to be timed in relation to injection rate to ensure that maximal organ opacification is achieved as the middle of the organ is being scanned, that adequate hepatic and portal vein opacification is achieved, and that streaking from the renal pelvis is minimized.

Adolescent↗
PubMed1992

Postoperative technetium scanning in patients with submandibular duct diversion.

Submandibular duct diversion is a common procedure for refractory sialorrhea in children. The procedure reroutes Wharton's ducts from the floor of the mouth to the tongue base. As the majority of saliva in the resting state is produced by the submandibular glands, rerouting markedly decreases sialorrhea. However, the procedure has been criticized in that diversion may cause fibrosis and stricture of the ducts. The gland would atrophy, and the physiologic functions of saliva would be lost. Glandular function of six patients with cerebral palsy (mean age, 14.7 years) was evaluated by technetium scanning (mean time after surgery, 43 months). Four patients had normal bilateral function; two patients had no function in one gland but normal function in the contralateral gland. We conclude that bilateral submandibular duct diversion maintains long-term function in at least one gland.

Adolescent↗
PubMed1992

Gastric emptying using three different formulas in infants with gastroesophageal reflux.

The role of delayed gastric emptying (GE) in the pathogenesis of gastroesophageal reflux (GER) in infants is controversial at present. GE has been shown to be altered by the composition and osmolality of the feedings. This prospective study was undertaken to assess the changes in the GE and the percentage of time GER was detected by scintigraphy using three different formulas on consecutive days in infants with GER. Twenty-eight infants under 1 year of age diagnosed to have GER by extended intraesophageal pH monitoring (pH being less than 4.0 for greater than 5% of the duration of the test), underwent scintigraphy on three consecutive days using the same volume per single feeding of a casein-predominant, soy, or a whey-hydrolysate formula in a randomized order. The formulas were isocaloric. Gastric emptying and percentage of GER into the esophagus were estimated for 60 min following these feedings. Mean GER percent during the study was 20.39, 17.68, and 16.34 on casein-predominant, soy, and whey-hydrolysate formulas, respectively, and was not significantly different. Mean values of GE were 39.7%, 44.6%, and 48.5% on casein, soy, and whey formula, respectively. No significant difference in GE was also observed between casein-predominant and soy formula. However, a significant difference was observed (p less than 0.05) on GE between casein-predominant and whey-hydrolysate feedings. Our data suggest that formula selection may be important in the treatment of conditions associated with delayed gastric emptying.

Gastric Emptying↗
PubMed1991

Septal ventricular pacing in the immature canine heart: a new perspective.

Cardiac pacing initiated from epicardial or transvenous apical right ventricular electrodes causes asynchronous ventricular contraction. This alters myocardial stress vectors and results in adverse cellular and subcellular changes in the experimental animal. Clinically, such changes may contribute to the adverse hemodynamics reported with long-term ventricular pacing. To determine the feasibility of direct stimulation of the ventricular specialized conduction systems and therefore the potential for maintenance of normalized depolarization patterns, 13 beagle puppies were studied. Baseline ventricular activation and contraction patterns were obtained using intracardiac electrograms and multigated nuclear acquisition (MUGA) imaging. Septal electrode insertion from the aortoatrial groove was accomplished by use of two-dimensional echocardiography and continuous electrocardiographic (ECG) monitoring of the surface ECG during pacemaker implantation in five puppies. Standard right ventricular epicardial electrodes were implanted in five additional animals, with three remaining as age-matched non-paced controls. After 4 months of observation, repeat MUGA imaging and intracardiac electrograms demonstrated nearly normal biventricular activation and contraction patterns among the septal-paced group. Histopathologic examination illustrated normal cellular morphology in the septal-paced animals. This study demonstrates that pacing electrode insertion into the proximal interventricular septum is feasible and results in utilization of the normal ventricular conduction pathway. Such an approach to initiation of ventricular stimulation may attenuate the adverse effects of long-term ventricular pacing.

Animals↗
PubMed1991

Comparison of indium-111 scintigraphy and colonoscopy with histologic study in children for evaluation of colonic chronic inflammatory bowel disease.

Indium-111 leukocyte scanning and colonoscopy were performed in 19 children and adolescents with chronic inflammatory bowel disease to study the correlation of evaluation between these two diagnostic modalities in comparison to histologic study for colonic disease. Seven patients had ulcerative colitis, 10 had Crohn's disease, and two patients had no specific diagnosis after evaluation. The sensitivity of indium-111 scan was 18%, specificity was 62.5%, and accuracy for diagnosing colonic disease was only 37%. In comparison, sensitivity and specificity for colonoscopy were 100 and 57%, respectively. Furthermore, accuracy with colonoscopy was 84%. Our data suggest that the usefulness of scans is limited to patients in whom standard diagnostic procedures are contraindicated. In addition, it is essential to confirm the visual diagnostic impression on colonoscopy with histologic study.

Adolescent↗
PubMed1990

Myocardial performance and perfusion during exercise in patients with coronary artery disease caused by Kawasaki disease.

For a study of the natural history of coronary artery lesions after Kawasaki disease and their effect on myocardial blood flow reserve with exercise, five such patients underwent exercise testing on a bicycle. Oxygen consumption, carbon dioxide production, minute ventilation, and electrocardiograms were monitored continuously. Thallium-201 scintigraphy was performed for all patients. One patient stopped exercise before exhaustion of cardiovascular reserve but had no evidence of myocardial perfusion abnormalities. Four patients terminated exercise because of exhaustion of cardiovascular reserve; one had normal cardiovascular reserve and thallium scintiscans, but the remaining patients had diminished cardiovascular reserve. Thallium scintigrams showed myocardial ischemia in two and infarction in one. No patient had exercise-induced electrocardiographic changes. These results indicate that patients with residual coronary artery lesions after Kawasaki disease frequently have reduced cardiovascular reserve during exercise. The addition of thallium scintigraphy and metabolic measurements to exercise testing improved the detection of exercise-induced abnormalities of myocardial perfusion.

Adolescent↗