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PubMed2005

Validation of a Chinese version of the dental anxiety inventory.

OBJECTIVES: To translate the English version of Dental Anxiety Inventory (DAxI) and its short-form (SDAxI) and to validate their use in Hong Kong Chinese. METHODS: The DAxI and SDAxI were translated into Chinese. A total of 500 adults (18-64 years) were interviewed, the Chinese DAxI, Symptom Checklist 90 (SCL-90), Depression Anxiety Stress Scales (DASS) and State-Trait Anxiety Inventory (STAI) were completed. Based on their initial DAxI scores, 135 interviewees were invited to attend a dental examination 1 month later. Then, the subjects completed the DAxI again, together with Beck Anxiety Inventory (BAI) which measured the state anxiety level of the participants. Two months after the initial interview, all 500 subjects were asked to complete the DAxI again. Another 300 adults were recruited and interviewed for the SDAxI validation. RESULTS: Cronbach's alpha of the Chinese DAxI and SDAxI were 0.77 and 0.80 and the test-retest correlation coefficients were 0.90 and 0.84, respectively. High correlation between BAI and DAxI scores and its stability over time supported construct validity of the Chinese DAxI. Small positive correlations between the DAxI and other subscales of the SCL-90, DASS and STAI supported discriminant validity of the instrument. The SDAxI demonstrated comparable validity and reliability with DAxI. CONCLUSION: The translated Chinese DAxI demonstrated good validity and reliability. It is available for use in dental anxiety research in adult Chinese. In situations where a short-form is desirable, the Chinese SDAxI is a simple, valid, reliable and interpretable scale for measuring dental anxiety in both research and dental practice.

Adolescent↗
PubMedDate not supplied

Construction and validation of a body image rating scale: a preliminary study.

PURPOSE: To construct and validate a preliminary version of a scale for use in routine screening of body image disturbances in nursing practice. METHODS: A five-stage procedure consisting of item construction, analysis of content validity, analysis of reliability, analysis of construct validity, and analysis of the discriminant validity of the scale. FINDINGS: At the end of the current stage of development, the preliminary version of the scale consisted of 23 items, demonstrating stability, adequate internal consistency, and discriminant validity between subjects in the upper and lower groups of scores. CONCLUSIONS: Although the psychometric properties of the scale have been delineated, the scale needs further psychometric evaluation and testing in different settings/samples so its clinical validity and reliability can be confirmed. PRACTICE IMPLICATIONS: The preliminary version of the body image rating scale has the potential to provide the nurse with reliable and valid information about a person's mental image of his/her own body. Using it can help nurses to identify possible body image disturbances and to plan individual nursing interventions.

Adult↗
PubMed2006

Validation of a voice prosthesis questionnaire to assess valved speech and its related issues in patients following total laryngectomy.

OBJECTIVES: To establish the reliability and validity of a new self-administered questionnaire to assess valved speech and its related issues in patients who have undergone a total laryngectomy operation. DESIGN: Cross-sectional psychometric validation study. SETTING: Tertiary cancer care centre. PATIENTS: We identified sixty-one total laryngectomy patients with no sign of recurrent disease and using voice prosthesis from the speech and language therapy database of the Royal Marsden Hospital. The patients were assessed using a postal self-administered voice prosthesis questionnaire concerning the voice valve and it's related issues. Patients were also asked to complete the University of Michigan voice related quality of life and University of Washington head and neck quality of life (version 4) questionnaires. MAIN OUTCOME MEASURES: Test-retest and internal consistency reliability; content; criterion and construct validity. RESULTS: We received completed questionnaires from fifty-one of the sixty-one total laryngectomy patients identified for the study providing a response rate of 84%. The median age of the group was 65 years (range: 40-85) with thirty-seven males and fourteen females. The internal consistency reliability using the Cronbach's alpha coefficient was 0.87 (range: 0.85 to 0.89). Test-retest reliability showed that more than 75% of patients had a score on re-test that was within 1 point of their original score. Content validity was ensured during the design process. The median Spearman correlation coefficient was 0.25 for convergent construct validity with the University of Washington head and neck quality of life questionnaire and 0.64 for criterion validity on comparison with the University of Michigan voice related quality of life scale. CONCLUSIONS: The voice prosthesis questionnaire is the first validated and reliable self-administered questionnaire designed specifically for evaluating valved speech and its related issues in patients who have undergone total laryngectomy. The voice prosthesis questionnaire has significant utility for audit, outcomes research and monitoring in this unique group of patients.

Adult↗
PubMed2000

Validation of an instrument for injury data collection in rugby union.

OBJECTIVE: To provide the basis for collecting rugby union injury data using a rigorously validated injury report form. METHODS: Seven stages were used to assess face, content, and criterion validity of the rugby union injury report form. A 22 member panel plus four sporting bodies assessed the form for face validity, and an expert panel assessed it for content and criterion validity. Panel members were consulted until consensus was reached. A yardstick developed by an expert panel using the Delphi technique was used to assess the reliability of the form. An independent panel of 10 viewed a series of five videotaped injuries, three times over a five week period to assess inter-rater and intrarater reliability. The form was then trialed by 40 people in situ during four games. RESULTS: The rugby union injury report form for games and training was developed, and the face, content, and criterion validity successfully assessed. A seven step protocol to create a yardstick was also developed to assist in the validation process. Both inter-rater and intrarater reliability results indicated a 98% agreement. The 40 trialists who completed forms in situ during four games were found to have an inter-rater reliability agreement of 98% for nine injuries. CONCLUSIONS: A measurement instrument for injury data collection in rugby union was successfully developed and validated, providing researchers with a basis for future studies in this area. A procedure to develop future injury data collection instruments in other sports was also developed.

Data Collection↗
PubMed2002

Quality assessment for three common conditions in primary care: validity and reliability of review criteria developed by expert panels for angina, asthma and type 2 diabetes.

OBJECTIVES: To field test the reliability, validity, and acceptability of review criteria for angina, asthma, and type 2 diabetes which had been developed by expert panels using a systematic process to combine evidence with expert opinion. DESIGN: Statistical analysis of data derived from a clinical audit, and postal questionnaire and semi-structured interviews with general practitioners and practice nurses in a representative sample of general practices in England. SETTING: 60 general practices in England. MAIN OUTCOME MEASURES: Clinical audit results for angina, asthma, and type 2 diabetes. General practitioner and practice nurse validity ratings from the postal questionnaire. RESULTS: 54%, 59%, and 70% of relevant criteria rated valid by the expert panels for angina, asthma, and type 2 diabetes, respectively, were found to be usable, valid, reliable, and acceptable for assessing quality of care. General practitioners and practice nurses agreed with panellists that these criteria were valid but not that they should always be recorded in the medical record. CONCLUSION: Quality measures derived using expert panels need field testing before they can be considered valid, reliable, and acceptable for use in quality assessment. These findings provide additional evidence that the RAND panel method develops valid and reliable review criteria for assessing clinical quality of care.

Angina, Unstable↗
PubMed2003

Validation of the GSFQ, a self-administered symptom frequency questionnaire for patients with gastroesophageal reflux disease.

BACKGROUND: Although the diagnosis of gastroesophageal reflux disease (GERD) is based primarily on symptoms experienced by a patient, relatively little attention has been paid to the development and validation of self-administered questionnaires specific to GERD symptoms. The present article presents the validation of the short, self-administered GERD Symptom Frequency Questionnaire (GSFQ). METHODS: Patients with GERD participating in a randomized clinical trial comparing pantoprazole and nizatidine were asked to complete the GSFQ together with validated instruments for measurement of health-related quality of life (Medical Outcome Study Short Form 12) and gastrointestinal symptoms (Gastrointestinal Symptom Rating Scale). Completion of the GSFQ, Medical Outcome Study Short Form 12 and Gastrointestinal Symptom Rating Scale took place upon entry into the trial (baseline) and during the trial (days 7 and 28). Endoscopy was performed at baseline and after 28 days. Cronbach alpha was used to assess the internal consistency of the questionnaire. The test-retest reliability of the GSFQ was examined by the intraclass correlation coefficient among the 36 patients with stable GERD symptoms between day 7 and day 28. Construct validity was assessed by comparing the GSFQ with previously validated instruments. Known group validity was determined by comparing GSFQ scores across groups of patients known to differ clinically. Responsiveness to change was assessed by the Guyatt's statistic. RESULTS: Two hundred twenty-one patients formed the study baseline group. The analysis demonstrated that the GSFQ questionnaire had excellent psychometric properties shown by the high internal consistency (Cronbach alpha 0.84); that the test-retest reliability was satisfactory (intraclass correlation coefficient 0.64); that there was good evidence that the GSFQ indeed measured what it was intended to measure (validity); and that the GSFQ was highly responsive to change (Guyatt's statistic 1.48). DISCUSSION: The GSFQ is a short, self-administered, easy to use, GERD-specific questionnaire which should be considered as a useful assessment tool in the evaluation of patients with GERD and in the assessment of treatment outcomes.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2006

The Contact Lens Impact on Quality of Life (CLIQ) Questionnaire: development and validation.

PURPOSE: To develop and validate a questionnaire for the measurement of the impact of contact lenses on quality of life (QoL): The Contact Lens Impact on Quality of Life (CLIQ) Questionnaire. METHODS: The questionnaire was developed and validated using conventional methods and Rasch analysis to assure content validity, repeatability, construct validity, and low respondent burden. Item identification and selection (647 items) were performed with an extensive literature review, professional advice, and lay focus groups. Item reduction used focus groups and data obtained from 161 subjects completing a 90-item pilot questionnaire. Validity and reliability, from data of 128 additional subjects, were assessed using Rasch analysis, intraclass correlation coefficient, and Bland-Altman limits of agreement. RESULTS: A 28-item CLIQ Questionnaire was developed and shown to have good validity and reliability by Rasch analysis statistics: real person separation, 2.02; model person separation, 2.17; reliability, 0.80; root mean square measurement error, 2.73; mean square+/-SD infit, 1.01+/-0.18; outfit, 1.01+/-0.19. The items (mean score, 49.8+/-4.9) were well targeted to the subjects (mean score, 51.2+/-6.2) with a mean difference of 1.35 (scale range, 0-100) units. Test-retest intraclass correlation coefficient (0.86) and coefficient of repeatability (+/-8.00 units) demonstrated good repeatability. CONCLUSIONS: Rasch analysis and standard psychometric analyses demonstrated that the 28-item CLIQ Questionnaire is a valid and reliable measure of QoL in contact lens wearers. A scoring algorithm is provided for CLIQ Questionnaire users to convert raw scores into the Rasch analysis-derived linear person measures.

Adolescent↗
PubMedDate not supplied

The importance of the prediction model in the validation of alternative tests.

An overview is presented of the validation process adopted by the European Centre for the Validation of Alternative Methods, with particular emphasis on the central role of the prediction model (PM). The development of an adequate PM is considered to be just as important as the development of an adequate test system, since the validity of an alternative test can only be established when both components (the test system and the PM) have successfully undergone validation. It is argued, however, that alternative tests and their associated PMs do not necessarily need to undergo validation at the same time, and that retrospective validation may be appropriate when a test system is found to be reliable, but the case for its relevance remains to be demonstrated. For an alternative test to be considered "scientifically valid", it is necessary for three conditions to be fulfilled, referred to here as the criteria for scientific relevance, predictive relevance, and reliability. A minimal set of criteria for the acceptance of any PM is defined, but it should be noted that required levels of predictive ability need to be established on a case-by-case basis, taking into account the inherent variability of the alternative and in vivo test data. Finally, in view of the growing shift in emphasis from the use of stand-alone alternative tests to alternative testing strategies, the importance of making the PM an integral part of the testing strategy is discussed.

Animal Testing Alternatives↗
PubMed2005

Systems validation: application to statistical programs.

BACKGROUND: In 2003, the United States Food and Drug Administration (FDA) released a guidance document on the scope of "Part 11" enforcement. In this guidance document, the FDA indicates an expectation of a risk-based approach to determining which systems should undergo validation. Since statistical programs manage and manipulate raw data, their implementation should be critically reviewed to determine whether or not they should undergo validation. However, the concepts of validation are not often discussed in biostatistics curriculum. DISCUSSION: This paper summarizes a "Plan, Do, Say" approach to validation that can be incorporated into statistical training so that biostatisticians can understand and implement validation principles in their research. SUMMARY: Validation is a process that requires dedicated attention. The process of validation can be easily understood in the context of the scientific method.

Clinical Trials as Topic↗
PubMed2005

Validation of a patient-administered questionnaire to measure the activity impairment experienced by women with uncomplicated urinary tract infection: the Activity Impairment Assessment (AIA).

BACKGROUND: To validate a questionnaire to assess the activity impairment associated with uncomplicated urinary tract infection (uUTI). METHODS: The Activity Impairment Assessment (AIA) assesses the amount of time an individual's work or regular activities have been impaired as a result of their UTI. The measure was completed by 276 women with uUTI who had participated in a prospective, open-label, non-comparative multi-centre clinical trial of CIPRO XR (extended-release ciprofloxacin). Baseline scores on the King's Health Questionnaire (KHQ) and clinical symptom evaluations were collected for validation purposes. RESULTS: An exploratory factor analysis showed that all items loaded > 0.84 on a single component. This uni-dimensional structure was supported by Rasch analysis. The AIA was found to have excellent levels of internal consistency (Cronbach's alpha = 0.93), convergent validity (all rs > .70) and divergent validity (rs = .078). The AIA displayed excellent discriminant validity in relation to clinical evaluations, and was found to be responsive to change across all clinical evaluations. CONCLUSION: The unidimensional AIA shows high levels of internal reliability, convergent and divergent validity, discriminant validity and responsiveness. It is an excellent tool for measuring activity impairment in UTI.

Activities of Daily Living↗
PubMed2005

Cross-cultural validation and analysis of responsiveness of the QUALIOST: QUAlity of Life questionnaire In OSTeoporosis.

BACKGROUND: The QUALIOST was designed for use with the SF-36 to measure established osteoporosis-specific quality of life (QoL). The reliability (internal consistency and test-retest) and validity of the questionnaire were established in a stand-alone psychometric validation study. The objective of this paper is to provide additional information on the instrument's responsiveness using clinical trial data, along with the reliability and validity of translated versions. METHODS: The Spinal Osteoporosis Therapeutic Intervention (SOTI) was an international clinical trial comparing strontium ranelate to placebo on the occurrence of new vertebral fracture in patients with postmenopausal osteoporosis. QoL was a secondary endpoint, assessed using the SF-36 and QUALIOST at baseline and every six months, with the main analysis at 3-year follow-up. Questionnaire acceptability, analysis of the hypothesised structure, internal consistency reliability and responsiveness to clinical change over time were assessed at the 3-year follow up. RESULTS: 1592 patients from 11 countries completed at least one QoL questionnaire. The psychometric properties of the questionnaires were assessed on cross-sectional (N = 1486) and longitudinal (N = 1288) data. Item discriminant validity of the QUALIOST was excellent, as was item convergent validity, with 100% of item-scale correlations being above the 0.40 level. Internal consistency reliability was also extremely good, with high Cronbach's alpha scores above the 0.70 benchmark. Responsiveness results were consistent for all QUALIOST scores, indicating that greater decreases in QoL corresponded to greater numbers of fractures experienced. QUALIOST scores also differed according to the type of fracture suffered. This was demonstrated by increased effect sizes for more severe vertebral fractures (clinical vertebral and painful vertebral). In comparing responsiveness, the QUALIOST scores were generally more consistent than those of the SF-36. Most notably, the QUALIOST was more responsive with regard to painful vertebral fractures than the SF-36. CONCLUSION: The QUALIOST is a reliable and valid tool for measuring QoL in postmenopausal osteoporotic women. Being available in several validated language versions, it is ready to be used in a variety of settings, including international clinical trials.

Activities of Daily Living↗
PubMedDate not supplied

Construct validity of the Chinese version of the Patient-rated Wrist Evaluation Questionnaire (PRWE-Hong Kong Version).

With increasing economic globalization, including health care, it is important to use standardized outcome measures applicable to a broad spectrum of patients in a wide array of countries. The purpose of this study was to verify construct and content validity and reliability of the Chinese version of the Patient-rated Wrist Evaluation Questionnaire (PRWE-Hong Kong version). The PRWE was translated into Chinese, and face validity was established by inviting experts and patients to participate in the panel review of the questionnaire. A correlation field study was performed using a convenience sample of 47 patients with wrist injuries. Patients were assessed at baseline and six weeks after the initial measurement. The following measures were taken: the Chinese version of the PRWE and the Medical Outcome Short Form (36) Health Survey (SF-36), Visual Analogue Scale (VAS) for pain, active wrist range of motion, grip strength, and the Jebsen Hand Function Test. Statistical analysis consisted of Pearson correlation coefficients (convergent validity), factor analysis (content validity), paired t-test (convergent validity), and the Cronbach alpha (internal consistency). Clinically relevant correlations existed between "Pain at rest" and the VAS "resting pain" (r=0.785, p<0.0001) as well as between "Pain on repeated wrist movement" and the VAS "exertion pain" (r=0.872, p<0.0001). The "Physical Component Summary" of the SF-36 was found significantly correlated with the PRWE function subset total score (r=-0.618, p<0.0001), and the PRWE total score (r=-0.645, p<0.0001). The specific function subset score also correlated with the wrist flexion range (r=-0.308, p<0.0001) and the grip strength (r=-0.488, p=0.035). Two factors were found that accounted for 61% of the variance. The Cronbach alpha coefficients ranged from 0.7805 to 0.9502, indicating that the internal consistency of the questionnaire items was sound and reliable. Positive correlations between the wrist ranges of motion (ROM) and the specific function subset score showed that the function subset measured dimensions related to wrist-specific performance in activities of daily living. Factor analysis results supported the construct validity of the PRWE-Hong Kong version in wrist-injured patients. Internal consistency testing results suggested that item consistency within subset items was good and persisted over time. In conclusion, the Chinese version of the PRWE is a reliable and valid self-rated tool in measuring treatment outcome. It supplements traditional objective clinical measures and is potentially applicable in Hong Kong clinical settings.

Activities of Daily Living↗
PubMed2004

The readiness to change questionnaire: reliability and validity of a Swedish version and a comparison of scoring methods.

OBJECTIVES: The aim of this study was to investigate the relative merits of three methods of scoring the Swedish version of the Readiness to Change Questionnaire (RTCQ), either by assigning a stage in the Prochaska and DiClemente (1986) Stages of Change Model or by treating the scores as a continuous readiness to change variable. Assigning a stage of change was achieved with both the quick method and the refined method. DESIGN AND METHODS: Out of 563 patients screened at an emergency surgical ward for risky alcohol consumption, 165 met risk criteria and responded to the RTCQ. The three scoring methods were examined with regard to internal consistency, test - retest reliability, construct and predictive validity. RESULTS: All three methods of treating the RTCQ scores had satisfactory reliability. Since stages of change (quick method) were significantly but modestly correlated to alcohol consumption and to change-related behaviours at intervention, and moderately correlated to alcohol problems, the quick method had reasonable construct validity. The refined method had higher construct validity; however, this method left 32% of the patients without a stage assignment. The continuous readiness scale had higher construct validity than the quick method, but was not in par with the refined method. No scoring method was found to have predictive validity. CONCLUSIONS: The RTCQ scores treated as a continuous readiness scale were a viable alternative to the original ways of assigning a stage of change to a patient. The Swedish RTCQ is reliable and has reasonable construct validity, but its predictive validity needs further investigation.

Adolescent↗
PubMed2004

Chronic liver disease questionnaire: translation and validation in Thais.

AIM: Quality of life (QOL) is a concept that incorporates many aspects of life beyond "health". The chronic liver disease questionnaire (CLDQ) was developed to evaluate the impact of chronic liver diseases (CLD) on QOL. The objectives of this study were to translate and validate a liver specific questionnaire, the CLDQ. METHODS: The CLDQ was formally translated from the original version to Thai language with permission. The translation process included forward translation, back translation, cross-cultural adaptation and a pretest. Reliability and validity of the translated version was examined in CLD patients. Enrolled subjects included CLD and normal subjects with age- and sex-matched. Collected data were demography, physical findings and biochemical tests. All subjects were asked to complete the translated versions of CLDQ and SF-36, which was previously validated. Cronbach's alpha and test-retest were performed for reliability analysis. One-way Anova or non-parametric method was used to determine discriminant validity. Spearman's rank correlation was used to assess convergent validity. P -value <0.05 was considered statistically significant. RESULTS: A total of 200 subjects were recruited into the study, with 150 CLD and 50 normal subjects. Mean ages (SD) were 47.3(11.7) and 49.1(8.5) years, respectively. The number of chronic hepatitis: cirrhosis was 76:74, and the ratio of cirrhotic patients classified as Child A:B:C was 37(50%): 26(35%): 11(15%). Cronbach's alpha of the overall CLDQ scores was 0.96 and of all domains were higher than 0.93. Item-total correlation was >0.45. Test-retest reliability done at 1 to 4 wk apart was 0.88 for the average CLDQ score and from 0.68 to 0.90 for domain scores. The CLDQ was found to have discriminant validity. The highest scores of CLDQ domains were in the normal group, scores were lower in the compensated group and lowest in the decompensated group. The significant correlation between domains of the CLDQ and SF-36 was found. The average CLDQ score was strongly correlated with the general health domain of SF-36. (P=0.69: P=0.01). CONCLUSION: The translated CLDQ is valid and applicable in Thais with CLD. CLDQ reveals that QOL in these patients is lower than that in normal population. QOL is more impaired in advanced stage of CLD.

Adult↗
PubMed2006

Using self-reported data to assess the validity of driving simulation data.

In this article, we use self-reported driving behaviors from a written questionnaire to assess the measurement validity of data derived from a driving simulation. The issue of validity concerns the extent to which measures from the experimental context map onto constructs of interest. Following a description of the experimental methods and setting, an argument for the face validity of the data is advanced. Convergent validity was assessed by regressing behaviors observed in thedriving simulatoron self-reported measures of driving behaviors. Significant relationships were found across six measures: accidents, speeding, velocity, passing, weaving between traffic, and behavior at stop signs. Concurrent validity was evaluated with an analysis of simulator accident involvement and attention deficit hyperactivity disorder status. Discriminant validity was assessed using a multitrait-multimethod matrix of simulator and questionnaire data. We concluded that although the relationship between self-reported behaviors and observed responses in the simulator falls short of perfect correspondence, the data collected from the driving simulator are valid measures of the behaviors of interest.

Adolescent↗
PubMedDate not supplied

Reliability and validity of the Test of Visual-Perceptual Skills (Non-Motor)--Revised for Chinese preschoolers.

OBJECTIVE: The reliability and validity of the Test of Visual-Perceptual Skills (Non-Motor)-Revised (TVPS-R) were examined for its usefulness on Hong Kong Chinese preschoolers. METHOD: Content validity was evaluated by six experts. Test-retest reliability, construct validity, and criterion validity were examined on 66 typically developing preschoolers while concurrent validity was examined on these preschoolers plus 52 preschoolers with visual-perception difficulties. RESULTS: Test-retest reliability was high for the total score (intraclass correlation coefficient [ICC] =.88), but not for all subtests (ICC ranged .38 to .77) or for individual items (mean kappa = 0.32). The standard error of measurement (SEM; 1.53) and internal consistency (Cronbach's alpha = .90) were satisfactory. Evidence supporting the test's validity included a significant developmental trend (F = 4.99, p < .001), a lack of gender bias (F = .04, p = .84), and positive known-group differentiation (Wilks's lambda = 52.42, p < .001). The correlation between the Motor-Free Visual-Perceptual Test-Revised composite score and the TVPS-R composite was moderate at r = .60. CONCLUSIONS: When based on the total scores, the TVPS-R was reliable and valid. The use of subtest scores and item scores for decision making or treatment planning is not recommended.

Analysis of Variance↗
PubMed1997

VATAM: developing consensus in validation of health telematics applications.

VATAM (Validation of Telematics Applications in Medicine) is an EU supported project in the Health care sector of the Telematics Application Programme. Its objective is to assist other health telematics projects by providing a platform for discussion on validation, eventually resulting in 'guidelines for validation of telematics applications in medicine'. The VATAM work can be subdivided into three phases: the inventory phase (1996) in which information is collected on validation approaches in the Telematics Application Programme, previous efforts and expertise. The dissemination phase (1997) will be used to extend and adapt the framework developed in the inventory phase, through cooperation with other projects The experiences phase (1998) in which the projects are actually applying validation, will be used by VATAM to validate the VATAM methodology. VATAM has finished the inventory phase successfully and is now working on the dissemination phase by--among others--establishing contacts with other projects, and providing information on the inventory through the World Wide Web (URL: http:(/)/www-vatam.unimaas.nl). This paper discusses the approach adopted and the proposed VATAM framework to structure the large variety of validation approaches.

Computer Communication Networks↗
PubMed2004

Validation of a new ultrasound method for the measurement of carotid artery intima medial thickness and plaque dimensions.

BACKGROUND: Carotid ultrasound is an accepted method for the detection of subclinical atherosclerosis. Valid methods that allow quantitation of carotid atheroma burden may be useful for stratifying risk. OBJECTIVE: To validate the results of intima medial thickness (IMT) and plaque measurements using a newly created software algorithm by comparing them with those obtained using a previously validated method. METHODS: Carotid ultrasound videotapes (n=24) were analyzed by experienced observers using a validated method and a new method. Ultrasound parameters were compared by measuring the difference +/- SD to yield indexes of accuracy and precision. Performance was also assessed using correlation and Bland-Altman analyses. RESULTS: Average IMT (n=24), plaque area (n=46), and several indexes that integrate IMT and plaque measurements were all found to be comparable with measurements obtained using the previously validated method. For example, the plaque area showed excellent accuracy and precision (-0.17+/-2.0 mm2, P=0.56), excellent correlation (r=0.98, standard error of the estimate = 2.01 mm2, P<0.001) and no evidence of bias using Bland-Altman analyses (Spearman's rho = 0.04, P=0.82). CONCLUSIONS: A new algorithm for the quantitation of carotid atheroma burden yields results that are comparable with those of a previously validated and widely used method. Availability of valid tools for measuring carotid ultrasound should facilitate the incorporation of this procedure into clinical risk stratification paradigms.

British Columbia↗