Toward comparability of coronary magnetic resonance angiography: proposal for a standardized quantitative assessment

A method is proposed for the quantitative assessment of coronary magnetic resonance angiography (MRA) acquisitions. The method is based on four parameters: signal-to-noise ratio (SNR); contrast-to-noise ratio (CNR); vessel length; and vessel-edge definition. A pig model (n=7) was used to illustrate the proposed quantitative analysis method. Three-dimensional gradient-echo coronary MRA was performed with and without exogenous contrast enhancement using a gadolinium-based blood-pool contrast agent (Vistarem, Guerbet, Aulnay-Sous-Bois, France). The acquired images could be well differentiated based on the four parameters. The SNR was calculated as 9.0±1.4 vs 10.4±2.1, the CNR as 6.2±0.8 vs 8.2±0.9, the vessel length as 48.2±11.6 vs 86.5±13.8 mm, and the vessel-edge definition as 4.9±1.5 vs 7.7±3.4. Different coronary MRA techniques can be evaluated objectively with the combined use of SNR, CNR, vessel length, and vessel-edge parameters.     

Mycobacterium tuberculosis Beijing genotype

Molecular epidemiologic studies of strains of Mycobacterium tuberculosis are currently conducted worldwide. The genetically distinct Beijing family of strains has been associated with large outbreaks of tuberculosis, increased virulence, and multidrug resistance. However, in this first population-based search for Beijing strains in the Danish DNA fingerprint database, analysis of 97% of all culture-positive tuberculosis patients in 1992 to 2001 showed that 2.5% of 3,844 patients, 1.0% of Danish-born patients, and 3.6% of immigrants (from 85 countries) had Beijing strains. No Beijing strains were found among 201 strains from Danish-born patients sampled in the 1960s, and no evidence of an increase in Beijing strains was found over time. The true prevalence of Beijing strains worldwide is unknown because only a fraction of global strains have been analyzed.     

Three-dimensional quantification of color-marked occlusal paths on anatomically oriented casts

STATEMENT OF PROBLEM: The analysis of occlusal contacts on mounted diagnostic casts is an important task in prosthetic diagnostics. However, it is still restricted mainly to qualitative aspects because existing measuring techniques fail to provide 3-dimensional data for more than a few single points in acceptable time. PURPOSE: The aim of this study was to develop a method for quantifying occlusal contacts and paths by using anatomically oriented diagnostic casts and to design the method to allow fast acquisition of digital 3-dimensional coordinates. MATERIAL AND METHODS: Plaster casts with color-marked contacts were digitized optically with a profilometric system based on the fringe projection technique. Digital camera images taken simultaneously were used to define the contact areas by marking them either manually or automatically with the help of image-processing routines. Three-dimensional coordinates were determined by finding the corresponding points within the profilometric data set. RESULTS: Color-marked contact areas on diagnostic casts were successfully digitized with a computer-controlled, automatic setup in approximately 30 seconds. The accuracy of the acquired 3-dimensional data was estimated to be better than 60 microm in lateral and 30 microm in height resolution. The data set was visualized and evaluated in a skull related coordinate system. SUMMARY: This study verified the use of a new tool to quantify color-marked occlusal contacts on diagnostic casts in terms of spatial coordinates. The resulting digital data may be stored easily and analyzed numerically as well as visualized 3-dimensionally with computer graphic equipment. Because the anatomic orientation of the casts is maintained throughout the measurement process, it is possible to compare the data with electronically registered condyle paths and therefore to investigate, for example, their relation to the corresponding guidance paths of the frontal teeth and the canines in dynamic occlusion.     

Clinical Predictors of Sleep Apnea in Patients Undergoing Bariatric Surgery

Background: Sleep apnea is a frequent and unappreciated condition of morbidly obese patients. If unrecognized it could lead to significant postoperative complications. A clinical tool to assess the severity of sleep apnea is not available.We prospectively determined whether the Epworth Sleepiness Scale (ESS) or body mass index (BMI) predict the severity of sleep apnea in morbidly obese patients. Methods: 66 consecutive patients evaluated for bariatric surgery from June to November 1999 were examined and prospectively administered a health questionnaire including the ESS. Patients with an ESS ≥ 6 were referred for polysomnography with calculation of Respiratory Disturbance Index (RDI). Sleep apnea was graded as mild (RDI 6-20), moderate (RDI 21-40) and severe (RDI>40). Clinical variables such as BMI and ESS score were compared using regression analysis. Data are mean ± SEM. Results: 4 men and 23 women (27/66) who scored >6 on the ESS completed a sleep study. Mean ESS was 13 ± 4.5. Sleep apnea was mild in 13 patients, moderate in 7, severe in 6, and absent in 1. Mean age was 43 ± 9.5 years. BMI was 52 ± 10 kg/m². Linear regression analysis did not demonstrate correlation between ESS score and severity of sleep apnea (r²=0.03, p>0.05). Multiple regression analysis demonstrated no correlation between BMI, patient snoring, and RDI score. Conclusions: Sleep apnea is frequent in candidates screened for bariatric surgery. ESS is a useful tool to investigate daytime sleepiness and other manifestations of sleep apnea. However, the ESS does not predict the severity of sleep apnea. Clinical suspicion of sleep apnea should prompt polysomnography.     

Perennial rhinitis: an analysis of skin testing, serum IgE, and blood and smear eosinophilia in 201 patients

Allergen skin testing, eosinophil counting in blood and nasal smear and serum IgE determination were performed in patients with simple perennial rhinitis, and in patients with rhinitis and asthma. The results were compared with those obtained in normal controls. As a positive skin test was demonstrated in 40% of patients with simple rhinitis and in 88% of patients with rhinitis and asthma, skin testing is considered relevant in all patients with perennial rhinitis. While blood eosinophil count and serum IgE level were elevated in a fair proportion of asthmatic patients, only a few subjects with simple perennial rhinitis had an elevated level, and the diagnostic values of these tests is questionable. On the other hand, examination of a nasal smear for eosinophils could usually separate the patients from the controls. The study emphasizes the importance of making a distinction between simple perennial rhinitis and perennial rhinitis associated with other symptoms and diseases.     

Community‐Based Practice Experience of Unsuspected Breast Magnetic Resonance Imaging Abnormalities Evaluated With Second‐Look Sonography

Objective. The purpose of this study was to assess the utility and efficacy of second‐look breast sonography in the evaluation of abnormalities identified on presurgical breast magnetic resonance imaging (MRI) examinations. Methods. A retrospective review was performed of 152 presurgical breast MRI examinations having 196 unsuspected abnormalities to identify findings that underwent subsequent breast sonography. Eligible examinations had a suspicious abnormality identified on presurgical MRI and documentation of the location and size of the finding on MRI and subsequent second‐look sonography. Fourteen examinations not meeting the criteria were excluded, with 182 abnormalities remaining. Patient medical records were reviewed. Results. Seventy percent (128 of 182) of breast MRI lesions were visible at second‐look sonography; 30% (54 of 182) were sonographically occult. Ninety‐five percent (121 of 128) of sonographically visible abnormalities underwent breast biopsy. Pathologic examinations of sampled sonographically visible lesions revealed 39 cancers, 9 high‐risk lesions, 72 benign lesions, and 1 lesion not specified at surgery; 23% (9 of 128) of cancers were in the contralateral breast. Fifty‐four lesions were sonographically occult. Needle biopsy was performed for 93% (50 of 54) of occult lesions, revealing 8 cancers, 1 high‐risk lesion, and 41 benign lesions; 3 of the benign lesions did not have sufficient pathologic specimens but were benign at follow‐up. Magnetic resonance imaging guidance was used in 86% (43 of 50) of these biopsies. One contralateral cancer was identified in the sonographically occult subset. Of the 182 lesions that underwent second‐look sonography, 20% (36 of 182) had a change in management. Conclusions. Second‐look sonography has value in the evaluation of abnormalities found on breast MRI. We found enhancements in 70% (128 of 182), yielding 39 cancers.     

A system model for closed-circuit inhalation anesthesia. I. Computer study.

Developing a custom computer program to simulate the uptake, distribution, and elimination of inhalational anesthetics allows the anesthesiologist to address specific problems, but extensive skills are required to translate the involved processes first into a set of mathematical equations and then into a satisfactory computer program. The first step is often facilitated by solutions offered in the literature. The second step demands computer proficiency that is often not available, but this problem can be obviated by means of a special-purpose simulation language (SPSL). We therefore constructed a model for closed-circuit inhalation anesthesia with the aid of the block-structured SPSL TUTSIM. Noticeable differences with previous models are that the linear, 14-compartment basic model does not assume a constant alveolar concentration and mimics circulation times through the use of blood pools. Advanced features of the SPSL were used to develop variants of the basic model to simulate feedback-controlled isoflurane administration, nitrous oxide uptake, and the impact of a nonlinearity by incorporating the effect of enflurane on cardiac output. Two variants were concatenated to form a multiple model showing the concentration and second-gas effects. The model was capable of reproducing the anesthetic uptake from previous experimental studies for nitrous oxide. After its validation for other anesthetic agents, the model can be used for clinical, teaching, and research purposes. The SPSL freed the authors from the problems associated with computer programming and allowed them to concentrate on the structure of the model.     

Noncardiogenic pulmonary edema caused by decompression sickness: rapid resolution following hyperbaric therapy

Noncardiogenic pulmonary edema is a recognized but uncommon manifestation of type 2 decompression sickness. It typically occurs within 6 hours of a dive. Because the adult respiratory distress syndrome in this setting is believed to be due to microbubbles in the pulmonary vasculature, recompression in a hyperbaric chamber has been recommended as a form of therapy. A patient developed noncardiogenic pulmonary edema following a seawater dive to 75 feet. There was complete radiologic and clinical resolution within 5 hours of hyperbaric therapy.     

Intraindividual variation and effect of learning in lung function examinations. A population study

The aims of this study were to analyse the influence of co-operation and instruction on inter-and intraindividual variations of normal lung function and to provide reference values for intraindividual variation. A sample of 125 non-smokers (age 30-70 yr) representative of the population of Copenhagen were studied with spirometry, complete and partial flow-volume curves, nitrogen washout volume, volume of trapped gas and transfer factor. The examination was repeated 0.5-6 months later for 112 of the individuals. Much of the variance observed at the first examination, i.e. interindividual variation, could be accounted for by the sex, age, height and weight of the individuals, whereas differences in individual motivation, social status, the ability of the technicians to instruct during the examination and interactions induced by the subject and the technician being of the same or of opposite sex were negligible. The intraindividual difference between the second and the first examinations were very small. Factors such as the subjects' sex, age, height, weight, social status, motivation, whether the examination was conducted by the same or a different technician at the two examinations, and whether the interval of time between the two examinations was short or long, were insignificant. It is concluded that while much of the interindividual variance of a lung function test is influenced by a variety of confounding factors, the intraindividual variation is not. Reference values for intraindividual variation are given.