Biomedical subjects

P Anninos

Publications and source records attributed to P Anninos.

At least 19 recordsLinked to original sources

PubMed2003

Differential diagnosis of prostate lesions with the use of biomagnetic measurements and non-linear analysis.

The purpose of this study was to investigate the biomagnetic activity emitted from the prostate gland and to differentiate cancerous from benign prostate lesions with the use of biomagnetic measurement and non-linear analysis. Magnetic recordings were obtained from 47 patients with palpable prostate lesions. Histology revealed 24 prostate cancer patients and 23 benign prostate hyperplasia (BPH) patients. The superconducting quantum interference device (SQUID) biomagnetometer was used to measure the prostate's magnetic field by placing the SQUID detector 3 mm above the symphysis pubis. The magnetic field recorded in the 2-7 Hz frequency range was of high amplitude in most malignant lesions whereas all benign cases were of low amplitude. According to our results, the sensitivity, specificity, positive predictive value and negative predictive value were 83.33%, 100%, 100% and 85.18%, respectively. By applying the Grassberger-Procaccia algorithm to the magnetoprostatogram time series in malignant and benign prostate lesions we found clear saturation in malignant prostate lesions with m>7 whereas in the benign lesions there was not clear saturation. Prostate cancer emits higher biomagnetic activity than the BPH. This confirms a higher angiogenic activity in prostate cancer than the BPH lesions. Furthermore, the saturation value in the estimation of the correlation dimension of the attractor for the cancer lesions confirms the lower complexity of the system in comparison to the BPH, which is characterized by higher complexity.

Aged↗

PubMed2003

Correlation between biomagnetic and Doppler findings of umbilical artery in fetal growth restriction.

OBJECTIVE: To assess the value of biomagnetic recordings of the umbilical artery over Doppler ultrasound screening in order to predict complications of impaired uteroplacental blood flow in fetuses with intrauterine growth restriction (IUGR). METHODS: Our study population included 11 IUGR preeclamptic (34-37-weeks gestation; birth weight 1969 +/- 129 g) and 19 normal pregnancies (34-37-weeks gestation; birth weight 3195 +/- 229 g). Umbilical artery Doppler ultrasound waveform measurements were expressed in terms of pulsatility index (PI). Biomagnetic signals (waveforms) recorded from the IUGR umbilical artery were expressed in terms of magnetic power spectral amplitudes. RESULTS: In all cases, the frequency band considered was 2 to 7 Hz. The spectral amplitudes were low (mean: 117+/-24 fT/ radical Hz) in most (90.9%) IUGR pregnancies and high (mean: 224+/-37 fT/ radical Hz) in most normal pregnancies (89.5%). There was a statistically significant difference between normal and IUGR pregnancies with respect to spectral amplitudes (p < 0.0001), Doppler PI (p < 0.0005), pH (p < 0.0005) and Apgar score (p < 0.0005). Multiple linear regression analysis revealed an influence of PI, pH and Apgar scores on the biomagnetic values (ANOVA: p < 0.0005). CONCLUSION: Our data imply that biomagnetic values of the umbilical artery flow could prove to be a helpful method for the evaluation of fetal well being especially in pregnancies complicated with preeclampsia and growth restriction.

Adult↗

PubMed2003

Chaotic and periodic analysis of fetal magnetocardiogram recordings in growth restriction.

OBJECTIVE: We studied how chaotic and periodic heart rate dynamics differ between normal fetuses (n = 19) and intrauterine growth restricted fetuses (n = 11) at 34 to 37 weeks of gestation. We quantified the chaotic dynamics of each heart rate time series obtained by fetal magnetocardiography (FMCG) using correlation dimension. METHODS: The FMCG was recorded digitally by a single-channel biomagnetometer in an electrically shielded room of low magnetic noise. The position of the fetal heart was determined using ultrasonography. RESULTS: The correlation dimension was significantly lower in IUGR than in normal fetuses (p < 0.001, t-test). The periodic dynamics were also obtained by FMCG and measured by power spectrum. The low-frequency components and therefore the periodicity of the low-frequency range were significantly higher in IUGR than in normal fetuses (p < 0.001, t-test). CONCLUSIONS: The analysis of FMCG recordings may offer important perspectives to understand significant features of the heart function of the fetuses. This technique improves the recognition of IUGR fetuses over healthy ones and may help improve perinatal morbidity and mortality.

Adult↗

PubMed2003

Pre- and postsurgical biomagnetic activity in malt-type gastric lesions. A case report.

PURPOSE: To evaluate the biomagnetic activity of a low-grade mucosa-associated lymphoid tissue (MALT-) type gastric lymphoma, and to determine if this procedure could be an adjunct to endoscopic ultrasonography (EUS) in the assessment of the disease pre- and postsurgically. MATERIAL AND METHODS: A 47-year-old female with a 2-year clinical history of a low-grade MALT-type gastric lymphoma associated with Helicobacter pylori was examined. The disease showed no histologic remission after eradication of the H. pylori infection and subsequent treatment with chemotherapy and the patient was classified as stage II EA. A decision for surgical resection was made. Biomagnetic waveform recordings were made in the target area before and after surgery and the Fourier analysis of these recordings was performed. RESULTS: The gastric lymphoma biomagnetic waveforms showed high amplitudes (1.8 pT) before and low amplitudes (0.6 pT) after resection. The corresponding Fourier analysis demonstrated that the maximum spectral power of the presurgical measurement was elevated (mean 235 +/- 847 pT2/Hz) compared with that obtained postsurgically (mean 725 +/- 89 pT2/Hz). The difference was of statistical significance ( p < 0.0001, t-test). CONCLUSION: Biomagnetic monitoring of gastric lymphoma, which is an entirely new diagnostic modality, could be a supplement to EUS for assessing remission or persistence of disease with medical treatment during follow up.

Female↗

PubMed2002

Detection of non-linearity in schizophrenic patients using magnetoencephalography.

OBJECTIVE: The aim of this study is to investigate the presence of any non-linearity in the magnetoencephalographic recordings (MEG) from the temporal lobe of schizophrenic patients in comparison with controls, in order to find the differences underlying the brain waves. We calculated the correlation dimension, which is a measure of the complexity of the dynamic system, as well as the first Lyapunov exponent that indicates the system's unpredictability. METHODS: The schizophrenic group consisted of 3 men and 7 women aged 23-32 years (mean 27.2, SD=3.5) and the control group of 3 men and 6 women aged 26-35 years (mean 31.6 +/- 4.1). There were no significant differences between the two groups as far as age and sex were concerned. None of them received any medication. RESULTS: The analysis of the MEG in the schizophrenic group showed lower dimension complexity and moreover the first Lyapunov exponent presented lower values compared with the corresponding ones in the control group, which means lower information processing. CONCLUSION: EEG findings as determined by MEG and non-linear analysis may offer important perspectives to better understand brain function in schizophrenia.

Adult↗

PubMed2001

Linear analysis of fetal magnetocardiogram recordings in normal pregnancies at various gestational ages.

In this study we investigated the fetal magnetocardiogram recordings (FMCG) in 64 women, 21-30 years old, with single normal pregnancies and gestational ages 28-40 weeks. Spectral analysis was used to quantify heart rate variability and to identify the maturation of the autonomic nervous system. According to our results, there was an increase of the ratio LF/HF of the power spectrum, which reflects the maturation of the autonomous nervous system and also an increase in heart rate variability in the course of pregnancies, which was statistically significant (ANOVA test, P < 0.0005) comparing the R-R intervals of the number of cases in the four groups of 28-30, 37-40, 31-33 and 37-40 weeks of gestation. This study highlights some of the advantages of FMCG as a novel, non-invasive technique for obtaining useful clinical information.

Journal Article↗

PubMed2001

Fetal heart rate patterns in normal and ritodrine-treated pregnancies, detected by magnetocardiography.

OBJECTIVE: The aim of the present study was to test the validity of magnetocardiography in the diagnosis of fetal heart rate arrhythmias in normal pregnancies, as compared to the number of arrhythmias reported in other series, which were detected by use of other diagnostic techniques. We also evaluated the influence of ritodrine on the fetal heart rhythm in pregnancies treated for the risk of preterm labor by means of magnetocardiography, in order to provide preliminary results that could be utilized in the future establishment of magnetocardiography as a screening procedure in the diagnosis and management of fetal arrhythmias. METHODS: We performed a prospective study on two subgroups of pregnant women: one of 84 women with normal healthy singleton pregnancies and one of 68 pregnant women treated with ritodrine for the risk of preterm labor. RESULTS: The prevalence of fetal arrhythmias in the first subgroup was 3.5% (3/84), while in the second subgroup the prevalence was 16% (11/68). CONCLUSIONS: The incidence of fetal arrhythmias detected in our population of normal pregnancies was comparable to that reported in previous studies by use of other techniques. Results gained from the second subgroup, although not comparable to others, owing to lack of similar reports, led us to believe that magnetocardiography's advantages over conventional methods of fetal cardiac surveillance could highlight the technique as a useful screening procedure for the detection of preterm fetuses, which should be submitted to closer investigation, because of the arrhythmias caused by ritodrine infusion.

Adult↗

PubMed2001

Biomagnetic activity in the female breast at various physiological states.

PURPOSE: To investigate the biomagnetic activity produced physiologically by the various normally occurring states of the female breast: puberty, reproductive age, pregnancy, lactation and menopause. METHOD: The mammary glands of 90 healthy women were examined using a Superconducting Quantum Interference Device (SQUID). RESULTS: Biomagnetic activity was low at puberty (105.46+/-3.77 fT/square root(Hz)) and the menopause (111.66+/-25.06 fT/square root(Hz)), but was high during the reproductive years (142.13+/-20.70 fT/square root(Hz)), particularly in the hyperplastic states of late pregnancy (221.86+/-12.14 fT/square root(Hz)) and lactation (252.73+/-54.77 fT/square root(Hz)). The results were statistically significant (p<0.0001 ANOVA test). CONCLUSION: Our observations indicate the importance of SQUID in understanding the biomagnetic activity of the female breast at the various physiological states of life.

Adolescent↗

PubMed2001

Neonatal magnetocardiography and Fourier spectral analysis.

OBJECTIVE: In this study we investigated the relationship between heart rate variability (HRV) and respiration in healthy and probably asphyxiated infants using magnetocardiographic (MCG) recordings. METHODS: Ten healthy and eight infants from pregnancies complicated by preeclampsia with indications of mild perinatal asphyxia were included in the study. All were near term. Maternal age ranged from 16 to 39 years (mean = 29.05, SD = 6.13). Spectral analysis was used to find out any association between respiration and HRV. RESULTS: Respiratory sinus arrhythmia (RSA) was reduced in preeclamptic infants with indications of mild perinatal asphyxia. This difference was statistically significant (p < 0.0002, t-test), whereas the heart rate of the two groups was not statistically significant (p = 0.1, t-test). CONCLUSION: The results suggest that infants with indications of mild preeclampsia differ from controls in respiratory activity and this difference is independent of basal heart rate. Thus, spectral analysis could be useful for the estimation of influence of mild perinatal asphyxia in the RSA rhythm of newborns.

Asphyxia Neonatorum↗

PubMed2001

Neonatal magnetocardiography.

PURPOSE: The aim of the present study was to test the validity of magnetocardiography (MCG) in the estimation of neonatal cardiac rhythm using a single channel superconductive quantum interference device (SQUID). MATERIALS AND METHODS: Our study population consisted of 50 neonates who were delivered normally between 37-41 weeks of gestation from clinically uncomplicated pregnancies. There was also a neonate included in the study in which the diagnosis of "hypoplastic left heart syndrome" was demonstrated by U/S Doppler examination. Maternal age ranged from 18 to 39 years (mean=29.15, SD=6.13). RESULTS: Our study results revealed 44 neonates with normal cardiac rhythm, four with ventricular tachycardia (VT), one with ventricular tachycardia (VT) and extrasystolic beats and one with bradycardia. The neonate with the hypoplastic left heart syndrome presented frequent episodes of ventricular bigeminy in the magnetocardiographic trace. M-mode echocardiography confirmed the diagnosis of the seven cases of arrhythmia in our study group. CONCLUSION: Results gained from the study lead us to believe that MCG could provide clinical practice with a non-invasive, rapid and easy to perform method, which could be used as an adjunct to conventional methods for the evaluation of neonatal cardiac rhythm.

Arrhythmias, Cardiac↗

PubMed2001

Neonatal magnetoencephalography and spectral analysis.

PURPOSE: We performed a prospective study of neonatal brain function on 44 respective term neonates who were delivered normally, without any clinical signs of brain damage. Thirty were associated with a normal pregnancy and labor with normal values of Apgar scores, umbilical cord pH and birth weight, while 14 neonates were the result of pre-eclamptic pregnancy. METHODS-RESULTS: Biomagnetic measurements were performed by means of a Superconducting Quantum Interference Device (SQUID) in an electrically shielded room of low magnetic noise. Biomagnetic signals (waveforms) recorded from neonatal brains in the frequency range of 2-7 Hz were expressed in terms of magnetic power spectral amplitudes. These were low (mean value 163.2, SD 22.57) in almost all neonates from the "normal pregnancy" group, while they were high (mean value 211.6, SD 37.74) in most neonates from the "pre-eclamptic" group. The difference between the two groups was statistically significant (Student's t-test, p < 0.005). CONCLUSION: A statistically significant difference in spectral amplitudes of neonatal brain activity was observed between normal term neonates and the pre-eclamptic neonates. Biomagnetic measurements of neonatal brain activity could provide clinical practice with a promising procedure for assessing brain function.

Adolescent↗

PubMed1997

The hemodynamics of the umbilical artery in normal and pre-eclamptic pregnancies. A new application of SQUID biomagnetometry.

This study was set to investigate the hemodynamics of the feto-placental circulation in normal and pre-ecclamptic pregnancies using the biomagnetometer SQUID. Thirteen women with pre-eclampsia and 26 healthy women were studied. All were "near term". Biomagnetic signals (waveforms) were recorded from the umbilical arteries. After statistical Fourier analysis, the findings were assigned arbitrarily in terms of spectral amplitudes as high (200-300 fT/ root of Hz), low (80-150 fT/ root of Hz) and borderline (151-199 fT/ root of Hz). In all cases the frequencies considered were distributed in the range 2-7 Hz. Interestingly, the umbilical artery waveforms and the corresponding spectral densities were of high amplitudes in most (88%) normal pregnancies of low amplitudes in most (84.6%) pregnancies complicated with pre-eclampsia. These findings were of statistical significance and were correlated with fetal heart rate (FHR) monitoring, pH and Apgar score at 1 and 5 minutes; high amplitude cases were related with normal FHR monitoring, pH > 7.25 and Apgar score > 7, while low amplitude recordings were connected with abnormal FHR patterns, pH < 7.25 and Apgar score < 7. It is suggested that biomagnetic measurements of the umbilical artery flow, which is an entirely new application of SQUID technology, is a promising procedure in assessing fetal health, especially in high risk pregnancies.

Adolescent↗

PubMed1996