Fetal Well-being Evaluation by Determination of High Frequency Measurement Noise for Fetal Heart Rate Signal / 대한산부인과학회지

OBJECTIVE: This study was done to propose a new method of determining the cutoff frequency against measurement noise in fetal heart rate signal and to analyze the discriminating value for normal fetus (pH>7.15) and abnormal fetus (pH< or =7.15) by nonlinear method. METHODS: The patients were classified by umbilical artery pH (7.15) or base excess (-10 mEq/L). After removing the high frequency noise components at the cutoff frequency determined in this study, we calculated correlation dimension as a discriminating value for the normal and abnormal fetuses. RESULTS: After low pass filtering of fetal heart rate signal at the cutoff frequency, the numerical result of embedding dimension was 5.47+/-0.67 (normal), 4.43+/-0.60 (abnormal) (p<0.001), and correlation dimension was 2.51+/-0.43 (normal), 1.79+/-0.15 (abnormal). CONCLUSION: We could determine the cutoff frequency from the different fluctuation level between high frequency noise and principal signal according the cutoff frequency function. The detection of fetal distress was done objectively by this method. We could discriminate between normal fetus and abnormal fetus by correlation dimension as indicator for the nonlinear complexity.

Nonlinear Dynamic and Chaotic Analysis of Fetal Heart Rate in Fetal Distress / 대한산부인과학회잡지

OBJECTIVES: For estimating the antenatal fetal wellbeing to develop new analysis method of fetal heart rate(FHR) with electronic Fetal Heart Rate Monitoring(eFHRM) and computer. METHODS: Heart rate signal is received from distressed fetus using eFHRM. It is necessary to carry out low pass filtering as a preprocess for the nonlinear method. Nonlinear parameters are calculated and classified to investigate the relations between these parameters and values of umbilical cord blood gas. RESULTS: By dividing values of the umbilical cord blood gas into 5 fetuses of acidemic group and 17 fetuses of non-acidemic group after 22 neonates who presented fetal distress were born, the following results as compared with nonlinear chaotic analysis result were obtained. 1. Delay time through AMI for acidemic group was 16.80+/-3.11, and was higher than 15.41+/-2.27 for non-acidemic group, and is not significant in statistics. 2. Embedding Dimension calculated with FNN method was 5.60+/-2.07 for acidemic group, and 4.71+/-1.26 for non-acidemic group, and it was not significant statistically. 3. Correlation dimension for acidemic group was 1.41+/-0.20, and was higher than 1.10+/-0.38 for non-acidemic group, and is not significant in statistics. 4. Mean crossing value by isoangular return map was 28.80+/-11.34 for acidemic group, and 16.65+/-7.00 for non-acidemic group, and it was significant statistically(P=0.008). 5. In comparison of information entropy in 1-D ED, acidemic group was 6.32+/-0.38 and non-acidemic group was 6.20+/-0.28 and it was not significant statistically. Also, in comparison of value in 2-D ED, acidemic group was 10.20+/-0.34. It was higher than non-acidemic group of 9.51+/-0.43 significantly in statistics(P=0.004). But, in comparison of value in 2-D EP, acidemic group was 8.78+/-0.86 and non-acidemic group is of 9.22+/-0.74 and it wasn't significant statistically. And, 2-D ED(DI) value was 10.64+/-0.14 for acidemic group and 10.51+/-0.18 for non-acidemic group, and it wasn't significant statistically. CONCLUSIONS: By the above result, nonliner dynamics and chaotic analysis of heart rate data with computer can serve as a new diagnosis method which may estimate the fetal wellbeing with real time. Through further studies for establishment of diagnosis standard and computer programming, real time diagnosis method shall be applied to clinical practice.

Surgical Treatment of Intracranial Arachnoid Cysts

Eighteen patients with symptomatic intracranial arachnoid cysts underwent 27 surgical procedures between January 1990 and December 1995. These were analysed with respect to their surgical procedures and results, complications and prognosis retrospectively, with an attempt assess the efficacy of each surgical procedure. Thirteen patients underwent excision of the inner and outer membranes with fenestration procedures to the basal cisterns(primary excision group), resulting in excellent or good outcomes in 12 cases, of which three patients were subjected to secondary shunt procedures due to symptom recurrence in two and persistence of the cyst in one during follow-up radiological study. There were no significant complications in this primary excision group. Four patients out of five in the primary shunt group had good or excellent results. But shunt revisions had to be performed in two patients;of these two patients, one died from subdural empyema and sepsis while the outcome of the other one was satisfactory. The results of this study suggested that excision and fenestration should be considered as the primary procedure in patients with symptomatic intracranial arachnoid cyst, especially in the pediatric age group.

Diagnosis and Management of the Spontaneous Intracranial Vertebral Artery Dissection

The authors have dealt with six cases of spontaneous intracranial vertebral artery dissection during the past 3 years. Most of the patients were in their fourth or fifth decade of life, and men predominated. All except one patient had severe antecedent headache and half of the 6 cases were hypertensive. The presenting clinical features were subarachnoid hemorrhage, Wallenberg's syndrome, brain stem RIND(reversible ischemic neurologic deficit) and cerebellar infarct. The locations of the dissection were right vertebral artery in four patients, right vertebral and basilar artery in one and left vertebral artery in another one. Most of the patients showed typical intramural hematoma or double lumen on the MRI. In the MR angiography, irregular segmental narrowing of vertebral artery or invisible pathologic vertebral artery were demonstrated. The angiographic findings included alternating irregular stenotic and dilated segment(pearl and string sign), aneurysmal dilatation, occlusion etc. four patients were treated medically while the other two were treated surgically by proximal vertebral artery clipping of the affected artery. Upon follow-up, the outcome were excellent in two, good in two and fair in two.

Multiple Intradural Schwannomas of the Cauda Equina in the Absence of Neurofibromatosis

A case of multiple intradural schwannomas of the cauda equina is reported without evidence of any other manifestations of neurofibromtosis. The patient had symptoms of cauda equina compression. Following a diagnosis of multiple intradural tumors of the cauda equina, based on lumbar spine MRI with contrast enhancement, the tumors at the L1 body, L3 body, L3-L4 intervertebral space level were removed completely, involving two rootlets. After the operation, the patient is asymptomatic apart from left S3 dermatome hypesthesia.

Complication and Reoperation after Surgery for Lumbar Disc Herniation

Retrospective analysis of reoperation and complication was made for 186 patients with lumbar herniated disc. The results showed complication rate of 7%(13 cases) and reoperation rate of 10.2%(19 cases). The primary complications were infections(9 cases), technical errors(2 cases), and scores(2 cases). Rate of discitis was 1.6%(3 cases). The outcomes of reoperation resulted in excellent recovery of 16%(3 cases) and good recovery of 58%(11 cases). The most common intraoperative findings of reoperation were inadequate disectomy or missed disc fragments 31.6% or 6 cases;epidural fibrosis 26.3% or 5 cases;and new herniation at other level 15.8% or 3 cases. Excellent and good results could be achieved in patients operated within 1 month or more than 6 months after while the patients who underwent reoperation between 1 month and 6 months showed poor results. The delicate perioperative menagement and complete discectomy, adequate bleeding control and laminectomy were considered to be essential in reducing the chance of complication and reoperation.

Nontraumatic Intracranial Dissecting Aneurysm of Vertebral Artery: Case Report

We present two cases with dissecting aneurysm of intracranial vertebral artery. One of them had brain stem infarction and the other one developed subarachnoid hemorrhage. Cerebral angiogram revealed fusiform dilatation with proximal and distal narrowing of the affected vessel. Magnetic resonance imaging showed subacute blood clot inthe right vertebral artery which suggested dissection. Differentiation from vasospasm and from atherosclerosis is critical. At surgical exposure, the aneurysms were appeared as dark-purplish sausage like masses. The proximal portions of the intracranial vertebral arteries were clipped. The post-operative courses were benign and at present they regained their normal daily lives.

The Clinical Significance of SPECT in Head Trauma

SPECT(single photon emission computed tomography) using 99m-Tc-HMPAO is a current method of identifying the relative condition of cerebral blood perfusion in pathologic conditions of the brain such as TIA, complete cerebral infarction, dementia, and psychologically ill states. The purpose of this article is to evaluate the significance of SPECT in head injuries. According to the other previous reports, there are several drawbacks in SPECT to evaluate the victims of head injury such as uncooperability of the patient, long scanning time. poor patient monitoring during the scanning time. poor availability, ete. The authors analyzed 54 cases of head injury patients, studying SPECT and CT in regard to the comparison of CT and SPECT, the relation of SPECT and the severity of the head injury, the duration of admission and the SPECT findings. The results were as follows: 1) In focal lesion, CT was more available for the quick evaluation of the location, size, and rapid decision making, and SPECT was available for the adjuvant method of postoperative follow-up. 2) In diffuse brain lesion, CT showed only the diffuse brain swelling and SPECT was available for more fine localization of the lesion. 3) In mild head injury, CT could not identify the location of the lesion and SPECT showed focal perfusion defects(55%).