Intraobserver and interobserver reproducibility of fetal biometry.

OBJECTIVE: To assess the intra- and interobserver reproducibility of ultrasound measurements of fetal biometric parameters. METHODS: We assessed the intraobserver and the interobserver agreement in measurements of fetal biparietal diameter (BPD), abdominal circumference (AC), head circumference (HC) and femur length (FL) on 122 singleton pregnancies. Patients were each examined twice by the first sonographer to determine the intraobserver reliability of measurements of fetal biometry. Subsequently, during the same ultrasound examination, a second blinded sonographer measured fetal biometric parameters to assess interobserver reliability. The consensus between and among observers was analyzed using the intraclass correlation coefficient (intra-CC) and interclass correlation coefficient (inter-CC) and the reliability coefficients (RC, alpha) for the four biometric measurements. A value > 0.75 was considered a reliable consensus for the intra-CC and inter-CC. A Bland and Altman plot was also created for the fetal biometric parameters to assess the repeatability of the measurements. RESULTS: Reliable consensus was observed for both the intra-CC and inter-CC and RC for all four biometric parameters. The intra-CC with the 95% CI and RC for the BPD, AC, HC and FL were as follows: 0.996 (0.995, 0.997), alpha 0.998; 0.994 (0.992, 0.996), alpha 0.997; 0.996 (0.994, 0.997), alpha 0.998; and 0.994 (0.992, 0.996), alpha 0.997, respectively. Similarly, the inter-CC with the 95% CI and RC for the same parameters were as follows: 0.995 (0.993, 0.997), alpha 0.998; 0.980 (0.971, 0.990), alpha 0.990; 0.994 (0.992, 0.996), alpha 0.997; and 0.990 (0.985,0.993), alpha 0.995, respectively. The Bland and Altman plots demonstrated a high degree of repeatability of BPD, AC, HC, and FL measurements. CONCLUSION: Our results demonstrate that the intra- and interobserver reproducibility of ultrasound measurements of fetal biometry are highly reliable.     

Intraobserver variation in Doppler ultrasound indices of placental perfusion derived from different numbers of waveforms.

Continuous-wave ultrasound is used to obtain records of Doppler-shifted frequencies from arteries. Indices using the maximum frequency envelope are usually derived from a number of selected waveforms on each record and averaged. Analysis of variance was performed on indices obtained from repeated Doppler ultrasound waveform records of uterine and umbilical perfusion in late pregnancy. Intraobserver variation was minimal when derived from six (consecutive) waveforms and was less than 10% for each index.     

Intraobserver and interobserver agreement in the diagnosis of anal sphincter tears by postpartum endosonography.

OBJECTIVE: To evaluate intraobserver and interobserver agreement in the diagnosis of anal sphincter tears by endosonography when performed immediately postpartum by resident obstetricians. METHODS: Fifty-four primiparous women who delivered vaginally and had no anal sphincter tears (third- or fourth-degree perineal tears) diagnosed clinically were recruited. Four observers assessed photographic prints and video recordings of anal endosonography performed before the suture of the perineum. We calculated the intra- and interobserver agreement and the kappa coefficient to quantify the reliability of the diagnosis of clinically occult sphincter tears. RESULTS: The observers described sphincter tears in 13-28% of the prints, and in 7-32% of the video recordings. Intraobserver agreement was rated as substantial for prints (kappa, 0.63), and moderate for video recordings (kappa, 0.48). The interobserver agreement was fair for prints (kappa, 0.34) and moderate for video recordings (kappa, 0.42). CONCLUSION: Endosonography performed immediately postpartum to diagnose anal sphincter tears is of moderate reliability.     

Intraobserver and interobserver reproducibility of ultrasound measurements of endometrial thickness in postmenopausal women.

OBJECTIVES: To determine intraobserver and interobserver reproducibility of ultrasound measurements of endometrial thickness in postmenopausal women. DESIGN: Forty-eight postmenopausal women underwent transvaginal ultrasound examination by two examiners. Each observer took three replicate measurements of the endometrium in each woman. Intraobserver repeatability was expressed as the difference between the highest and lowest measurement values obtained by one observer, the repeatability coefficient, and the intraclass correlation coefficient. Interobserver reproducibility was expressed as the difference between the mean of the three measurements of each observer, limits of agreement, and interclass correlation coefficient. The repeatability coefficient and the limits of agreement define the range within which 95% of the differences between two measurements are likely to fall. Data were analyzed for all women, as well as separately for women with endometrium < or = 6 mm and > 6 mm. The agreement between observers in classifying women as having endometrium < or = 4.4 mm or > or= 4.5 mm was determined by calculating Cohen's kappa. RESULTS: In women with endometrium 6 mm were 0.99 and 0.99, 0.7 mm (0-2.9) and 1.0 mm (0.2-3.4), and 1.7 mm and 1.9 mm. In women with endometrium < or = 6 mm the interclass correlation coefficient was 0.77, and the mean interobserver difference was 0.2 mm +/- 1.8 mm (2 standard deviations), when calculations were based on the mean of three measurements per observer (+/- 1.9 mm when calculations were based on only one measurement per observer). The corresponding figures for women with endometrium > 6 mm were 0.98, 0.2 mm +/- 3.1 mm (+/- 3.2 mm). The agreement between observers in classifying women as having an endometrium < or = 4.4 mm or > or = 4.5 mm was very good (kappa 0.81). CONCLUSIONS: The reproducibility of endometrial measurements seems to be clinically acceptable and to allow reliable discrimination between postmenopausal women with endometrium < or = 4.4 mm and > or = 4.5 mm. In clinical practice, it is enough to take one endometrial measurement when performing transvaginal ultrasound examination.     

Intraobserver and interobserver reproducibility of three-dimensional gray-scale and power Doppler ultrasound examinations of the cervix in pregnant women.

OBJECTIVES: To determine intraobserver and interobserver reproducibility of three-dimensional (3D) gray-scale and power Doppler ultrasound examinations of the cervix in pregnant women. METHODS: Thirty-two pregnant women underwent transvaginal 3D gray-scale and power Doppler ultrasound examination of the cervix by two examiners. Each observer acquired two volumes, and they each analyzed their volumes twice using the commercially available software Virtual Organ Computer-aided AnaLysis (VOCAL). The variables analyzed were cervical volume (cm3), vascularization index (VI), flow index (FI) and vascularization flow index (VFI). Intraobserver repeatability was expressed as the difference between two measurement results (mean difference +/- 2 SD, i.e. limits of agreement) and as intraclass correlation coefficient (intra-CC). Interobserver agreement was expressed as the difference between the results of the two observers (limits of agreement) and as interclass correlation coefficient (inter-CC). The contribution of various factors (examiner, acquisition, analysis of acquired volume) to intrasubject variance was estimated using different analysis of variance models. All statistical analyses were performed using log-transformed data. The results presented are those obtained after antilogarithmic transformation, i.e. the results are presented as ratios between two results of the same observer, or as ratios between the results of Observer 1 and Observer 2. RESULTS: All intraobserver and interobserver log-transformed differences were normally distributed. There was no systematic bias between the two observers. Both intra- and inter-CC values were high (0.93-0.98) for all variables except FI (0.63-0.88), despite the limits of agreement being wide, especially for VI (widest range 0.4-2.4) and VFI (widest range 0.3-2.6). Acquisition explained most of the intrasubject variance of the flow indices, the contribution of examiner and analysis being unimportant. CONCLUSIONS: Given the wide range between the lower and upper limits of agreement, it would probably not be possible to detect anything but large differences or changes in cervical volume or cervical flow indices using current 3D ultrasound techniques. Because acquisition explained most of the intrasubject variance, the average of several repeated acquisitions should be used to enhance reproducibility. However, it is not worth doing more than one analysis of an acquired volume, because the effect of analysis on measurement results is small.     

Intraobserver and interobserver agreement of grayscale typical ultrasonographic patterns for the diagnosis of ovarian cancer

The purpose of this study was to evaluate the intraobserver and interobserver agreement for identifying ovarian malignancy using typical grayscale ultrasonographic patterns. Digitally stored grayscale sonographic images from a random sample of 98 women with an adnexal mass submitted to surgery after a grayscale transvaginal sonography were evaluated by five different examiners with different degrees of experience in three European university departments of obstetrics and gynecology. Masses in which the echo features were highly characteristic of a benign pathology were categorized as benign. Any cystic mass containing excrescences, thick septations, multiple irregular septations or solid component in which the echo architecture was not highly suggestive of benign histology was categorized as malignant. Intraobserver and interobserver agreement according to the level of experience were assessed by calculating the kappa index. Of the 98 cases randomly selected, 28 (29%) were malignant masses and 70 (71%) were benign. Intraobserver agreement was good or very good for all examiners with different degrees of experience (kappa = 0.72 to 1). Interobserver agreement was good for all expert operators (kappa = 0.69 to 0.75). Interobserver agreement between experts and highly experienced operators was moderate or good (kappa = 0.51 to 0.63). Interobserver agreement between the moderately experienced operator and experts was fair to moderate (kappa = 0.29 to 0.46). Interobserver agreement between moderately and highly experienced operators was fair (kappa = 0.33). Our results indicate that ultrasonographic malignant patterns are reproducible, even in moderately experienced examiners, although more experience is associated with better interobserver agreement.     

Intraobserver variation in the radiological measurement of the anorectal angle

Seven experts drew the rectal axes of 18 representative proctographic images on two occasions, with a 1-year interval, in order to assess intraobserver variation in the determination of the anorectal angle (ARA). Intraobserver variation (6%) and interobserver variation (17%) were smallest when the central rectal axis was used to determine the ARA. A strong relation was found between inter- and intraobserver variation (r=0.77). Intraobserver variation tended to be rather small for pictures made during straining, but a relation with the magnitude of the ARA was not found. Although none of the seven experts could reproduce the rectal axes with 10% variation in all 18 pictures, redrawing of the central rectal axis delivered 10% variation in 86% of determinations. It is concluded that intraobserver variation is influenced by the expertise of the investigator, the method of analysis, and the anorectal configuration to be analyzed. Radiologic assessment of the ARA may yield reliable data on the dynamics of the anorectum if performed by a single investigator on x-ray films that allow confident analysis.     

Use of a curved-array transducer to reduce interobserver variation in sonographic measurement of thyroid volume in healthy adults

PURPOSE: Sonographic calculation of thyroid volume is used in the diagnosis and follow-up of thyroid diseases. Since the calculated volume of thyroid lobes is highly influenced by the longest (ie, craniocaudal) diameter, we examined whether using a curved-array transducer as opposed to a linear-array transducer to measure the craniocaudal diameter would reduce interobserver variation. METHODS: Three sonographers with different levels of expertise each used a 5-12-MHz linear-array transducer and a 2-5-MHz curved-array transducer to measure the craniocaudal diameter of both thyroid lobes of 25 healthy volunteers. On the basis of these measurements, thyroid lobe volumes were calculated. Single-factor analysis of variance was used to evaluate the interobserver variations between the measurements made by all 3 observers as well as between measurements taken by pairs of observers. A p value of less than 0.05 was considered significant. RESULTS: Using the linear-array transducer to measure the craniocaudal diameter resulted in significant interobserver variation in thyroid volume calculation (p = 0.02), whereas using the convex-array transducer did not. Using either transducer resulted in a highly significant interobserver variation in measurements of the craniocaudal diameter, although the variation was far more pronounced for measurements made with the linear-array transducer (p = 0.0005) than for those made with the curved-array transducer (p = 0.04). For both transducers, the interobserver variations were most pronounced between the most and the least experienced sonographers. CONCLUSIONS: To avoid significant interobserver variation in calculating thyroid lobe volume, we recommend using a curved-array transducer to measure the craniocaudal diameter of the thyroid lobes.     

Precision of umbilical artery Doppler studies. Intraobserver, interobserver, and biologic variability of fetal Doppler velocimetry

The use of Doppler ultrasound to study fetal blood flow has become commonplace, despite the lack of detailed evaluation of the testing tool for precision. In evaluation of 25 patients, no significant intraobserver differences were found between readings on an individual waveform, nor were there significant differences between different observers on individual waveforms. Temporally separated waveforms within a 30-minute window gave the greatest variation. A multi-way analysis of variance noted significant differences in this category only. This study confirmed the precision of measurements by a single observer and between observers. Only biological alterations over time displayed significant variability.     

Intraobserver and interobserver reproducibility of 3-dimensional power Doppler vascular indices in assessment of solid and cystic-solid adnexal masses.

OBJECTIVE: The purpose of this study was to assess the intraobserver and interobserver reproducibility of 3-dimensional (3D) power Doppler angiography-derived vascular indices in evaluation of vascularized solid and cystic-solid adnexal masses. METHODS: Stored 3D power Doppler angiographic volume data from 12 consecutive women with a diagnosis of a complex adnexal mass (6 cystic-solid and 6 solid) evaluated and treated at our institution were retrieved from our database for analysis. Two examiners performed the calculations blinded to each other. Calculations were performed offline in a computer using Virtual Organ Computer-Aided Analysis software (plane A, 9 degrees rotation step) to assess volume and vascularization (vascularization index, flow index, and vascularization-flow index) from solid areas within the tumor. In all cases, a definitive histologic diagnosis was obtained. Intraobserver and interobserver reproducibility was assessed by calculating the intraclass and interclass correlation coefficients for each index. RESULTS: All tumors proved to be malignant after surgical removal. Intraobserver reproducibility for both examiners and interobserver reproducibility were high for all indices (interclass correlation coefficient > 0.95). CONCLUSIONS: Three-dimensional power Doppler angiography is a reproducible technique for offline assessment of stored 3D volume data of vascularized adnexal masses.     

Intraobserver and interobserver variability of transabdominal Doppler velocimetry measurements of the fetal ductus venosus between 10 and 14 weeks of gestation.

OBJECTIVE: To assess the intraobserver repeatability and interobserver reproducibility of transabdominal Doppler ultrasound measurements of ductus venosus blood flow in fetuses between 10 and 14 weeks of gestation. DESIGN: A prospective study with the following end-points: coefficient of variation, intraclass correlation coefficients within and between observers, repeatability coefficient and Cohen's kappa coefficient. SUBJECTS AND METHODS: Doppler velocimetry indices (maximum peak systolic velocity during ventricular systole, end-diastolic velocity during atrial contraction, peak systolic velocity/end-diastolic velocity ratio and pulsatility index for veins) were successfully measured three times by the same trained observer in 67 fetuses. Of these, in 24 fetuses, the measurements were then repeated by a second trained observer. In addition, both observers classified qualitatively the blood flow as being normal or abnormal with regard to the presence or absence/reversal of flow during atrial contraction. RESULTS: The intraobserver repeatability of the pulsatility index for veins measurements was considered good with a coefficient of variation of 8.9% and an intraclass correlation coefficient value of 0.62. However, inconsistencies occurred in maximum peak systolic velocity, end-diastolic velocity and systolic/diastolic ratio measurements, which had coefficients of variation of 19%, 28.5%, and 25.4%, respectively. The corresponding intraclass correlation coefficient values were 0.70, 0.69 and 0.60. Interobserver reproducibility of these indices was unsatisfactory, the coefficient of variation varying between 11.5% and 47.2% and the intraclass correlation coefficient between 0.18 and 0.44. Agreement between the repeated observations with regard to interpretation of normal or abnormal blood flow varied from moderate (interobserver) to very good (intraobserver). CONCLUSIONS: There was considerable variability in all Doppler indices except for the intraobserver repeatability of the pulsatility index for veins measurement. This makes the implementation of the semiquantitative Doppler indices in a screening setting difficult. On the contrary, qualitative classification of the flow velocity waveforms seemed to be a reproducible method.     

Intraobserver reproducibility and interobserver agreement of ultrasonic flowmetry using the velocity profile color doppler method in the common carotid artery

Application of the velocity profile method is recommended for reliable measurement of flow volume in larger vessels, and ultrasonic flowmetry is a useful clinical tool for this purpose. We used the velocity profile in conjunction with a minor modification in the conventional velocity profile method and examined the reproducibility of flowmetry from color Doppler data. Data of three examiners were allowed to analyze intraobserver reproducibility and interobserver agreement in the common carotid artery, and we measured flow volume in the peripheral vessels of healthy individuals. Estimated flow volumes in five healthy examinees were 350 to 550 ml/min and did not vary significantly between examiners. Interobserver correlation was good (r ₁=0.63), but intraobserver correlations in two sonographers were excellent (r ₁=0.85) in by one who was experienced in this method and poor (r ₁=0.32) in the other. Good interobserver agreement and intraobserver reproducibility of experienced examiners suggests that this method is reliable. Values obtained with normal controls averaged 438±78 (mean±SD) ml/min and 449±64 ml/min, respectively, in the right and left carotid arteries (n=12) and 120±31 ml/min and 83±23 ml/min, respectively, in the right and left vertebral arteries (n=10). Normal values were 542±71 ml/min (n=11) in the right renal artery, 1210±211 ml/min in the abdominal artery (n=10), and 799±182 ml/min in the main portal vein (n=17). Arterial blood flow volume can measure reliably by the velocity profile color Doppler method.     

Interobserver variation in duplex sonographic scanning in the femoropopliteal tract.

The diagnostic value of duplex sonographic scanning was demonstrated in a number of studies, but there is lack of consensus on which characteristic of the Doppler spectrum correlates best with the severity of peripheral vascular disease. In a prospective study we quantified the interobserver variation in duplex scanning for the diagnosis of peripheral vascular disease. Forty-one patients with intermittent claudication were independently examined by two observers. The observers were unaware of the angiographic findings. Reproducibility of classification and separate characteristics of the Doppler spectrum were expressed as kappa coefficients, Pearson correlation coefficients, and repeatability coefficients. PSV was the most reproducible characteristic of the Doppler spectrum. The classification of peripheral disease in 0 to 19%, 20 to 49%, 50 to 99%, and 100% diameter reduction was highly reproducible (kappa 0.68). The other characteristics of the Doppler spectrum were moderately to poorly reproducible; wave form contour, spectral broadening, and end diastolic velocity had kappa values of 0.56, 0.20, and 0.56, respectively. Our findings justify a simplification of the criteria for duplex sonographic scanning for diagnosis of peripheral vascular disease.     

Intraobserver and interobserver variability of ovarian volume, gray-scale and color flow indices obtained using transvaginal three-dimensional power Doppler ultrasonography.

OBJECTIVE: To assess intraobserver and interobserver variability in ovarian volume and gray-scale and color flow index measurements using transvaginal, three-dimensional, power Doppler ultrasonography. METHODS: Eleven women (22 ovaries) were examined on day 8 of controlled ovarian hyperstimulation therapy, which was part of their in vitro fertilization treatment protocol. The patients were examined twice by the first observer and once by the second observer. The acquired volume datasets were analyzed using the VOCAL imaging program, enabling the assessment of ovarian volume, vascularization index (VI), flow index (FI), vascularization flow index (VFI) and mean grayness (MG). For these parameters the intraclass (intra-CC) and interclass (inter-CC) correlation coefficients, within-observer and between-observers repeatability coefficient (r) and limits of agreement were calculated. RESULTS: Both intraobserver and interobserver repeatability of ovarian volume measurements were considered very good with an intra-CC value of 1.00 and inter-CC value of 0.99, respectively. Also VI, FI, VFI and MG measurements were repeatable by a single observer, the intra-CC ranging from 0.82 to 0.91. The interobserver reproducibility was also good for VI, VFI and MG measurements (inter-CC values 0.73, 0.70 and 0.81, respectively), but for FI measurements the reproducibility was poor (inter-CC = 0.29, r = 7.87). CONCLUSIONS: In general, the intraobserver reproducibility was better than interobserver reproducibility for all parameters. The volume assessments were reproducible both by one observer and by two separate observers. The intraobserver and interobserver variabilities were acceptable for VI, VFI and MG, whereas for FI the interobserver reproducibility was poor. Our results suggest that measurement of gray-scale and color Doppler flow indices is reproducible thus allowing them to be used in clinical practice and research.     

Color Doppler sonographic assessment of placental circulation in the first trimester of normal pregnancy.

Our aim was to study placental circulation during the first trimester of normal pregnancy. For this purpose, 108 single pregnancies from 4 to 15 gestational weeks were evaluated through conventional Doppler ultrasonography. The flow velocity waveforms from the retrochorionic arteries (spiral-radial arteries) and the umbilical artery were assessed using the peak systolic velocity, resistive index, and pulsatility index). Intervillous flow velocity waveform was evaluated from the maximum velocity. The earliest color signal from the retrochorionic circulation was registered at 4.5 weeks along with gestational sac visualization. The venous Doppler signal from the intervillous space and the Doppler signal from the umbilical artery were recorded with an embryo visible from the end of week 5 onward. The retrochorionic, intervillous, and umbilical peak systolic velocities increase, whereas the resistive and pulsatility indices decrease progressively during early pregnancy with a significant correlation with gestational age. Similarly, intervillous maximum velocity gradually increases throughout the first trimester of pregnancy. Despite some methodologic problems related to Doppler technology and the vessels studied color Doppler sonography appears to be an adequate tool to assess the physiologic changes in the placental circulation during early pregnancy.     

A reevaluation of placental grading and its clinical significance

Pregnancies complicated by preeclampsia or intrauterine growth retardation have an earlier and faster placental maturation than normal. This is demonstrated in a study of 1,096 obstetrical examinations of 473 non-diabetic mothers. It is recommended that a pregnancy demonstrating grade I maturational changes prior to 27 weeks, grade II changes prior to 32 weeks, or especially grade III changes prior to 34 weeks be followed clinically and ultrasonically for possible complications.     

Endometrial thickness as measured by transvaginal sonography: interobserver variation.

Transvaginal sonography of the uterus has become an important tool for diagnosing endometrial pathology in women with postmenopausal bleeding. One parameter that has been claimed to be important for curly detection of endometrial pathology in this group of women is the endometrial thickness. The purpose of this study was to evaluate the reproducibility of measurements of endometrial thickness as performed by five inexperienced doctors and one doctor experienced in the transvaginal sonography technique. The endometrial thickness as measured by the experienced doctor was regarded as the 'true measurement', and the mean discrepancy from this true measurement was 1.5 mm for the inexperienced doctors. No endometrial pathology was found at the histopathological examination after dilatation and curettage (D & C) when the endometrial thickness was measured as 相似文献