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Objective To identify sensitivity and specificity of computerised cardiotocography (CTG) analysis for fetal acidosis during delivery. Design Retrospective observational study. Setting Tertiary referral labour ward, Technical University München (TUM) and University Witten/Herdecke (UWH). Population All deliveries, which had at least one fetal scalp pH measurement and electronically saved CTG traces, between 2000 and 2002 (TUM) and between 2004 and 2005 (UWH). Method Correlation analysis of fetal scalp pH values and computerised International Federation of Obstetrics and Gynecology (FIGO) classification using ‘CTG Online®’ program of digitally saved CTG traces. Main outcome measures Fetal scalp pH values, FIGO parameter (baseline, variability, acceleration and deceleration) using computerised analysis. Results Both collectives showed a high sensitivity (95.0%) for computerised FIGO classification ‘suspect’ and ‘pathological’, together with a low specificity (21.8%) for fetal acidosis. The most sensitive single FIGO parameter was deceleration. Very low sensitivity (<50%) was shown for the parameters variability and acceleration. Conclusions Computerised CTG analysis is highly sensitive for fetal acidosis and can be used as an objective adjunctive criterion during delivery. Further CTG data are needed to adjust and optimise each FIGO parameter and increase sensitivity and specificity. [ABSTRACT FROM AUTHOR]

Abstract: An important clinical application of fetal magnetocardiography (FMCG) is the identification and classification of fetal arrhythmias. However, separation of fetal and maternal signals can be challenging due to cardiac conduction disturbances and changes in signal morphology. In twin pregnancy, the presence of an additional cardiac signal further complicates data processing. We report on the processing of FMCG signals obtained in twin pregnancy in the 28th week with arrhythmia in a single fetus. A 12-min FMCG was recorded using a 61-channel biomagnetometer with sufficient coverage to simultaneously register both fetal cardiac signals. Using signal template matching, digital averaging and subtracting techniques, the cardiac signals of the mother and both fetuses could be separately identified and displayed. Examination of the timing of ventricular complexes in combination with their signal morphologies permitted the identification and classification of arrhythmic events. Two episodes of supraventricular tachycardia over total period of 3 min at heart rates around 280 bpm were present. The remaining trace showed intermittent changes between sinus beats, supraventricular extrasystoles and compensatory pauses as well as blocked atrial beats. We conclude that appropriate signal processing techniques permits the clinical interpretation of FMCG signals even in complex spatio–temporal combinations of signals. [Copyright &y& Elsevier]

Abstract: We investigated the viability of a 2-channel low temperature biomagnetometer system implementing 2nd order gradiometers in an unshielded environment. We examined 2 fetuses (30th, 38th week of gestation) in and outside a shielded room as well as 3 (weeks 32, 36, 37) in the unshielded environment of an obstetrics department. Reference fetal magnetocardiograms (FMCG) were registered in a shielded room using a 61-channel biomagnetometer. In the hospital, fetal heart position was estimated on the basis of sonography. Inside the shielded room, fetal cardiac signals were successfully registered by the 2-channel system and were comparable to those of the multichannel system. Outside the shielded room, only signals of the older fetus were identifiable (signal-to-noise ratio: 7 inside, 2 outside the shielded room). In the hospital, 5 to 8 measurements per fetus were performed. In one fetus (37th week), online cardiac signals could be obtained intermittently. This report of unshielded FMCG acquisition confirms that it is possible to register FMCGs in late pregnancy in an unshielded environment. However, further improvements in noise reduction are necessary to permit routine FMCG acquisition in hospital environments. [Copyright &y& Elsevier]

From adult data, it is known that numerous factors, such as age, state of the autonomic nervous system, diurnal rhythms or mean R-R interval mRR, influence heart rate variability (HRV). The aim of this study was the examination of the influence of gestational age, mRR, gender and time of day on fetal HRV. The analysis was based on 66 fetal magnetocardiograms (FMCGs) of 22 healthy fetuses between the 16th and 42nd week. FMCGs were recorded for 5 min using a multichannel biomagnetometer. On the basis of the time series of fetal R-R intervals, mRR as well as the standard deviation sdRR, root mean square of successive differences rmssdRR and approximate entropy ApEn were calculated. The influence of gestational age, mRR and gender on sdRR, rmssdRR and ApEn was determined by regression analysis. The relationship between time of day and HRV was evaluated by visual inspection of scatterplots. The logarithmised HRV measures increased significantly with the logarithm of gestational age (regression coefficients: sdRR = 1.28, rmssdRR = 1.12, ApEn = 1.30) and mRR (regression coefficients: sdRR = 0.008, rmssdRR = 0.011, ApEn = 0.012) There was no significant influence of gender. With respect to time of day (between 0800 h and 1800 h), no dependency of the HRV measures was apparent. In summary, when fetal HRV is assessed, it is essential to take gestational age and mRR into account. In contrast, time of day, with respect to daytime, and gender need not be considered. In future studies, the influence of fetal activity state on HRV should be examined. [ABSTRACT FROM AUTHOR]

Objective To evaluate the possibility of distinguishing between benign and malignant breast tumors using a computer-aided evaluation of echogenicity and echostructure of ultrasound findings at certain focal points. Study design The ultrasound images from 89 cases of breast tumor were documented under standardized conditions using a linear array machine and 7.5 MHz transducer. In each sonographic image, the maximum area of the ‘region of interest’ of the tumor was marked and then subjected to consecutive statistical analysis and correlation with the histological findings. For evaluation of tumor status eight parameters of first and second order texture statistics (gray level histogram, Fourier analysis, co-occurrence matrix) were applied. Results Benign tumors were clearly distinguished from carcinomas in the evaluation of the co-occurrence matrix and the Fourier analysis on the basis of Wilcoxon and Student t-test (P < 0.05) but not in the gray level histogram. Using logistic regression a sensitivity of 73.8% and a specificity of 54.2% were obtained. A statistically significant difference between benign tumors and moderately differentiated together with poorly differentiated carcinomas could be demonstrated. Conclusion This study concludes that texture analysis appears to distinguish between benign and most malignant tumors. A computer texture analyzing system is able to improve the subjective assessment of ultrasound images of the breast but can not replace it. Where the limits of subjective assessment of a given tumor are reached, computerized texture analysis will provide additional information in the differentiation of benign from malignant findings. [ABSTRACT FROM AUTHOR]

Purpose: Specimen sonography is necessary for successful surgical excision of non-palpable breast masses, discovered only in breast ultrasound. But is there any difference in echogenicity and echostructure between native and in vitro sonography? Methods: The ultrasound images from 46 benign and malignant breast tumors were documented under standardized conditions pre- and postoperative, using a linear array machine (Shimadzu, US device SDU-490) and 7.5 MHz transducer with a water path interposed between the transducer and skin or the plastic bag, containing the fresh specimens after surgical excision. Two images of each tumor were documented on a 3/4 in. Sony high-band video device (U-matic BVU-800-P), and the recordings were digitized with an 8-bit resolution in 384 × 288 pixels (frame grabber band, Ing. Büro Fa. Fricke, Berlin). In each sonographic image, the maximum area of the region of interest of the tumor was marked and then subjected to consecutive texture analysis and correlation to the histological findings. For evaluation of tumor status eight parameters of first and second order texture statistics (grey level histogram, Fourier analysis, co-occurrence matrix) were applied. Results: In all cases, the mass was clearly identified on sonograms obtained in the operating room. Fibroadenomas (n = 11), fibrocystic diseases (n = 5) and ductal carcinomas (n = 26) showed comparable results in texture analysis. On the other hand, lobular carcinomas (n = 4) were clearly different in all parameters, in especially mean of grey level, homogeneity and contrast (P < 0.001 on the basis of Wilcoxon and Student's t-test). Conclusions: In vitro examination is a rapid and efficient method of localizing impalpable breast masses in excised specimens, but differences in echostructure and echogenicity are possible. [ABSTRACT FROM AUTHOR]