Correlation between intracranial pressure (ICP) and changes in CT images of cerebral hemorrhage.

The relationship between intracranial pressure and CT images was investigated in 80 cases of cerebral hemorrhage that occurred between 1984 and 1990. In traumatic intracerebral hematoma, positive correlation was found between intracranial pressure and both shift of midline structures and volume of hematoma except in the occipital lobe or at the base of the frontal lobe. In nontraumatic intracerebral hematoma, increased intracranial pressure was found to correlate with changes in the configuration of the lateral ventricles, intraventricular hemorrhage, and compression of the basal cisterns and cortical sulci. No correlation between intracranial pressure and hematoma volume was observed, most likely due to the number of elderly patients in the subject population. In nontraumatic subarachnoid hemorrhage, positive correlation existed between increased intracranial pressure and intraventricular hemorrhage as well as Evans' ratio calculated using repeat CT images that were obtained due to disturbances in cerebrospinal fluid circulation. These results suggest that the degree by which intracranial pressure increases in patients with cerebral hemorrhage can be estimated by the changes in CT images.

CSF shunt physics: factors influencing inshunt CSF flow.

Cerebrospinal fluid (CSF) in a shunt does not have a constant flow rate. The flow fluctuates from 0.01 ml/min to 1.93 ml/min according to each patient's own daily supine rhythmic pattern. We determined and evaluated the factors influencing CSF flow in a shunt in 19 cases of hydrocephalus. Postural changes, such as head elevation, led to increases by over 0.04 ml/min in inshunt CSF flow, while inshunt CSF flow in the supine position was less than 0.04 ml/min. Respiratory changes, such as coughing and apnea-hyperventilation, also influenced inshunt CSF flow. Changes in intracranial pressure (ICP) corresponded to changes in inshunt CSF flow. Inshunt CSF flows were higher than average during the night, the flows being stimulated by increases in ICP especially during REM sleep.

Cine magnetic resonance imaging of aqueductal stenosis.

Cerebral aqueductal stenosis is one of the most common causes of congenital and acquired hydrocephalus, but the etiology, pathophysiology and cerebrospinal fluid (CSF) dynamics of aqueductal stenosis have yet to be clarified. Utilizing cardiac gated cine magnetic resonance (MR) imaging, we evaluated aqueductal configuration and pulsatile motion of brain and CSF flow stimulated by cardiac pulsation in five patients with non-tumoral aqueductal stenosis. Cine MR of four cases revealed obliteration of the aqueduct by thickening mesencephalic tectum, turbulent CSF flow in the III ventricle, and absence of flow-related signal void, which in all normal cases indicates CSF movement within the aqueduct. In the remaining fifth case, with proximal dilation of the aqueduct resulting from thinning of the tectum, distortion of caudal (distal) tectum related to pulsatile motion of the brain caused funnel-like narrowing of the aqueduct, leading to incomplete obstruction and the absence of upward CSF flow during diastole.

[A case of disproportionately large communicating fourth ventricle after resection of temporal astrocytoma that evolved an isolated fourth ventricle].

The isolation and enlargement of the fourth ventricle after a ventriculoperitoneal (V-P) shunt was classified as "isolated fourth ventricle (IFV)". The term, "disproportionately large communicating fourth ventricle (DFV)" was first introduced by Scotti et al as being an enlarged fourth ventricle communicating with the third ventricle. The authors present a case of DFV after the resection of an astrocytoma. Upon recurrence of the tumor a second resection was carried out 5 years later. It was found that IFV had evolved because a cyst in the right temporal lobe was obstructing the aqueduct. After shunting of the tumor cyst, the aqueduct was again found to be patent and the fourth ventricle gradually decreased in size. A 34-year-old female presented headache, nausea, and a mild left hemiparesis. An initial CT scan demonstrated a fourth ventricle of approximately normal size and a right temporal mass. The first craniotomy revealed an astrocytoma. A CT scan after the surgical procedure showed enlargement of all ventricles, especially the fourth, resulting from the blockage of the foramina of Luschka and Magendie. The insertion of a V-P shunt was followed by a reduction in size of all ventricles. The diagnosis of DFV was thus confirmed because the fourth ventricle had a demonstrated communication with the third ventricle. After a second craniotomy for tumor recurrence five years later, a CT scan revealed the enlargement of the fourth ventricle and a cyst in the right temporal lobe. A metrizamide CT scan revealed that the cyst was isolated and an RI ventriculogram confirmed obstruction of the aqueduct.(ABSTRACT TRUNCATED AT 250 WORDS)

Necessity for ICP monitoring to supplement GCS in head trauma cases.

The necessity for ICP monitoring together with GCS findings to detect deterioration in head trauma cases and determine the treatment required was studied. There were 18 subjects (14 males, 4 females) aged from 11 to 61. Cases of primary brain stem damage were excluded. Eight cases had GCS of 6-10, and 10 cases scores of 11-15. Initial CTs of these cases indicated the following conditions: thin acute extradural haematoma (A-EDH), thin acute subdural haematoma (A-SDH), brain contusion, and single or multiple intracerebral haematoma (ICH). However, in no case was any mass effect clearly shown. Medical decompression (osmotherapy, barbiturate, steroid and mechanical hyperventilation) was carried out with simultaneous ICP monitoring. Based upon our cases which showed a GCS score of 10 or less, ICP monitoring should accompany medical decompression. Where the ICP cannot be maintained below 20 mm Hg, there is a high risk (about 60%) of haematoma enlargement, delayed haematoma, or increasing brain oedema. ICP monitoring in these cases should be maintained for at least one week. Timely surgical decompression is necessary when the ICP stays above 20 mm Hg, the GCS score drops below 10, and repeat CT scan indicates progress of the mass effect.

[Tolerance and plasticity against the intracranial pressure in cases of chronic subdural hematoma in the aged brain].

A consecutive series of 94 patients with chronic subdural hematomas (CSDHs) was studied on compensation against intracranial pressure and tolerance, and plasticity from compression of CSDHs, comparing between 47 cases of the aged group over 70 years of age and 47 cases of the younger group under 69 years of age. Better compensation from compression of CSDHs in the aged group was demonstrated from the fact those of long duration from impact to onset of symptoms, few cases with signs of chronic intracranial hypertension and volume of hematoma over 100 ml. But, when CSDHs progressed over 100 ml in size, this compensation mechanism and also tolerance against increased intracranial pressure were deprived. Disturbance of consciousness and anisocoria were shown much more in the aged group on admission. Patients in the aged group demonstrated reduced brain reexpansion and poor clinical recovery during 3 months after surgery. CT performed on 3 months after surgery demonstrated persisting subdural fluid in 63% of cases in the aged group comparing with 8% of those in the younger group. There was significant difference about morbidity between two groups. These study suggests that the plasticity and elastance in the aged brain reduce because of brain atrophy and impairment of cerebral blood flow, then brain reexpansion and clinical improvement may participate in delay regardless of release from compression of CSDHs. It may be urged that the critical age maintaining the plasticity of the brain in cases with SDHs in 75 years of age.

Factors affecting cerebrospinal fluid flow in a shunt.

Nineteen hydrocephalic patients were studied to determine factors affecting cerebrospinal fluid (CSF) flow through shunts. This study was based on our previously reported method by which fluctuations in CSF flow through a shunt of from 0.01 ml min-1 to 1.93 ml min-1 were identified, each having its own rhythmic pattern. While CSF flow in a supine position was less than 0.01 ml min-1, head elevation to 60 degrees led to increases in CSF flow from 0.12 ml min-1 to 0.17 ml min-1. Sudden respiratory changes such as coughing also affected CSF flow. CSF flows were higher than average between 10 pm and 7 am, and changes in CSF flow were related to slight increases in ICP during REM sleep. There is no relationship between CSF flow in a shunt and daily fluid intake which varied from 27 ml kg-1 to 103 ml kg-1, and no significant changes in CSF flow resulting from rapid intravenous injection of Glycerol and Ringer's solution.

[Cerebrospinal fluid absorption mechanism--based on measurement of CSF flow rate in shunt tube].

The cerebrospinal fluid (CSF) absorption mechanism in cases of hydrocephalus was investigated on the basis of measurements of CSF flow in a shunt tube after ventriculo-peritoneal shunt surgery, monitoring of intracranial pressure, CT findings, radioisotope cisternography, cerebral blood flow, EEG, PSP tests and changes in neurological findings. The subjects were 6 males and 7 females aged from 18 to 70. CSF flow rates in the shunt tubes were between 0.01 and 1.93 ml/min. Calculating the daily volume of CSF flow, the subjects were divided into two groups: Group A (8 patients) with a volume of less than 150 ml/day (0.01-0.25 ml/min), and Group B (5 patients) with between 150 and 500 ml/day (0.01-1.93 ml/min). Monitoring of intracranial pressure prior to the shunt operation was performed in 10 cases. These pressure values ranged between 4 and 25 mmHg (mean: 7-8 mmHg), and there was no difference between the two groups. The pre-and post-operative radioisotope cisternography findings indicated improvement of ventricular dilatation, periventricular lucency and ventricular reflux. After the shunt operations, there was neurological improvement in 6 of the 8 Group A cases but only in 2 of the 5 Group B cases. Considering the CSF flow volumes of the two groups, it appears that in Group A the shunt tube is not the main CSF circulation pathway. This could mean that resistance to CSF absorption in the cerebrospinal space has decreased after the shunt operation and there has been recovery of the physiological CSF absorption pathways. In other words, neurological improvement can be expected in this group A.

Aneurysms associated with moyamoya disease.

Seven cases of moyamoya disease accompanied by an aneurysm were studied. The patients, two males and five females, were 13 to 57 years old (average, 32). The cases were classified into two groups: Group A (five cases), in which the aneurysm was located within the moyamoya vessels, and Group B (two cases), in which the aneurysm was located within the circle of Willis and remote from the moyamoya vessels. In all Group A cases, the presenting episode was intracerebral and intraventricular hemorrhage due to rupture of the aneurysm. One patient suffered two separate attacks. In this case, the aneurysm disappeared spontaneously. In one of the two Group B cases, there was hemorrhage from an anterior communicating artery aneurysm. In the other case, with a basilar-superior cerebellar artery aneurysm, there was hemorrhage from the moyamoya vessels.

[Osteoid oteoma associated with intraosseous meningioma. A case report].

A very rare case of intraosseous meningioma accompanied with osteoma is reported. A 57-year-old male was admitted with left chronic subdural hematoma and an operation was immediately performed. At the time of admission skull X-ray film showed a high density area in the right frontoparietal region. Postoperative CT scanning showed no abnormality at standard window, widths and levels or at higher window, widths and levels. 99m Tc MPP scinti gram showed increased activity in the right frontoparietal region. Tomography of the skull indicated hyperostosis involving all layers. This skull tumor was diagnosed as osteoma. At the second operation the osteoma was removed. There seemed to be no changes in the bone and underlying dura. Histological examination indicated multiple microscopic meningotheliomatous meningioma with psammoma bodies in Haversian canals, leading to the conclusion that this was osteoid osteoma. It is suggested that this case be designated as type Lopez II and that it raises some interesting points regarding histogenesis and development of meningioma.

A non-invasive CSF flowmeter.

A new non-invasive method for quantitative measurement of cerebrospinal fluid (CSF) flow in the ventriculo-peritoneal shunt tubing, used in hydrocephalus, has been developed. It is an implantable device which produces a bubble in the shunt tubing by electrolysis. This bubble is then detected in the tubing by an electrode arrangement using electric impedance or ultrasonically using a Doppler probe. The energy for electrolysis is supplied by extracorporeal high-frequency transmission. The CSF flow rate is calculated by the velocity of bubble flow in the tubing. CSF flow rates, ranging from 0.01 to 1.00 ml/min, have been measured in animal experiments with statistically good accuracy. In 11 clinical cases a flow range of between 0.01 and 1.93 ml/min have been observed.

[CSF dynamics following shunt operation, with special reference to the diurnal changes of CSF circulation].

The purpose of this study is to study the pathophysiology of the cerebrospinal fluid (CSF) formation and circulation after a ventriculoperitoneal shunt operation. With the CSF flowmeter we developed, the CSF flow rate in the shunt tube has been measured non-traumatically over a 24-hour period in six patients. These include both communicating and noncommunicating hydrocephalus patients with ages ranging from 20 to 70. There were three cases of ruptured intracranial aneurysm, one cerebral contusion, one hypertensive brain stem hemorrhage and one occlusion of the aqueduct sylvius. Intraventricular pressure was continuously recorded for 24 hours prior to the shunt operation in each case, and the pressure changes were compared with the measured CSF flow rates in the shunt tube. The flow rate fluctuated between 0.05 ml/min and 1.2 ml/min with the supine position and high flow rates were detected in the early morning. Each case showed its own rhythm of CSF flow fluctuation during a 24-hour period, and the changes were compatible with the intraventricular pressure. It is suggested that there may be a relationship between these changes and an increased cerebral blood volume during the REM sleep stage.

A new method for measuring cerebrospinal fluid flow in shunts.

An implantable device for measurement of cerebrospinal fluid (CSF) flow in a ventriculoperitoneal shunt tube has been developed. The unit is energized by an extracorporeal high-frequency generator (200 KHz), and electrolysis creates bubbles in the shunt tube. Velocity of bubble flow is detected by a pair of ultrasonic Doppler probes placed a certain distance apart on the skin surface and in parallel with the implanted tube. The CSF flow rate is calculated taking into account velocity and tube diameter, and is expressed in ml/min. The unit consists of a coil with a capacitor, a silicon diode to rectify the high frequency, and a Zener diode to regulate maximum output voltage of 20 V. The output is fed to a pair of platinum electrodes placed inside the unit's tunnel through which the CSF flows. These components are molded in epoxy resin and coated with medical-grade silicone rubber. In animal experiments, CSF flow rates ranging from 0.033 to 1.0 ml/min could be measured by this flowmeter. Clinically, CSF flow has been measured to date in several cases. In two cases of communicating hydrocephalus occurring after the onset of cerebrovascular disease, and in which the CSF flow was continuously monitored for 24 hours, the flow rate ranged between 0.05 and 0.78 ml/min. The CSF flow rate fluctuates in a 24-hour period, increasing in the morning, especially between 12 midnight and 6 a.m., which suggests a circadian rhythm.

[A device to measure CSF flow in a shunt tube and its clinical application].

An implantable device for measurement of cerebrospinal fluid (CSF) flow in a shunt tube has been developed. The unit is energized by an extracorporeal high frequency generator (200 kHz), and electrolysis creates bubbles in the shunt tube. Bubble flow velocity is detected as reflected sound using a pair of ultrasonic Doppler probes (Saneisokkuki Doppler Flowmeter Type 1935) placed apart on the skin surface and in parallel with the tube. CSF flow is expressed in ml/min. by calculating velocity and tube diameter. The unit consists of a coil with a 200 kHz capacitor, a silicon diode to rectify the high frequency, and a Zener diode to regulate maximum output voltage of 20 V. The output is fed to a pair of platinum electrodes inside the unit's tunnel through which the CSF flows. The unit is moulded in epoxy resin and coated with medical grade silicon rubber. In vitro, CSF flow rates ranging from 0.033 ml/min to 1.0 ml/min. could be measured by this flowmeter model. In vivo, however, it was difficult to detect a flow rate of less than 0.006 ml/min. To measure the slower flow rate, a so-called bubble-detecting-tube made from an 11 cm stainless steel tube coated with silicon rubber is centrally inserted between the two ends of the separated shunt tube. The bubble flow velocity is detected by a tissue impedance detector's pair of probes placed apart on the skin surface. Clinically, CSF flow was measured in three cases of hydrocephalus (two cases of normal pressure hydrocephalus and one case of pineal tumor with non-cummunicating hydrocephalus). The flow rates were found to be, respectively, 0.10 ml/min., 0.063 ml/min., and 0.20 ml/min. The merits of the unit include its ability to repeatedly measure CSF flow at short intervals, and also to measure dynamic CSF flow under various conditions.