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Results for “SUBARACHNOID SPACE”

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At least 37 records · Page 2Linked to original sources

PubMed2000

Lack of endotoxin tolerance with respect to TNF alpha production in the subarachnoid space.

To study endotoxin tolerance in the subarachnoid space 0.1 mg of endotoxin derived from Neisseria meningitidis was injected intracisternally into rabbits on 2 consecutive days. On day 1 the maximum peak level of TNF alpha was 7 ng/ml 2 h after injection, whereas on day 2 the highest levels were 3.6 ng/ml and 3.7 ng/ml, respectively, 1 and 2 h after injection. Pretreatment with intravenous endotoxin 5 or 21 h before consecutive intracisternal endotoxin did not affect the cerebrospinal fluid (CSF) levels of TNF alpha. In contrast, there was a marked endotoxin tolerance with respect to TNF alpha in the systemic circulation. Cells appearing in the CSF 5, 12 and 20 h after intracisternal injection of endotoxin were harvested, cultured, and then stimulated with 0.1 mg/ml of endotoxin. In 10 experiments a marked TNF alpha production in the range 10-70 ng/ml was detected in the supernatants, whereas unstimulated cells did not produce TNF alpha. We conclude that tolerance to endotoxin does not develop in the subarachnoid space as evaluated by the present experimental design. The pattern of TNF alpha production and endotoxin tolerance is distinctly different in the subarachnoid space and systemic circulation.

Animals↗

PubMed2005

An improved procedure for catheterization of the thoracic spinal subarachnoid space in the rat.

Catheterization of the subarachnoid space provides a convenient means to deliver drugs to, or collect cerebrospinal fluid from, the spinal cord in animal experiments, and has been instrumental to our understanding of spinal mechanisms that underlie anesthesia, analgesia, or cardiovascular regulation. Experience gained over the years has revealed several shortcomings of this technique. We report a procedure that encompasses the benefits of direct subarachnoid catheterization of the rat thoracic spinal cord but circumvents the known shortcomings. An intrathecal catheter was fabricated with a small silicon bead at one end of a PE-10 catheter, which was cannulated with a 4/0 suture that served as a guide. Using the L-shape hook of the suture guide as an anchorage, the catheter was advanced into the subarachnoid space until the silicon bead was lodged on a drilled hole (2 x 2 mm) over the lamina proper on the T13 vertebrae. With less surgical trauma, greater precision of placement and firmer anchorage of the catheter, less leakage of cerebrospinal fluid, and minimal mortality or morbidity, our modified procedure for catheterization of the thoracic spinal subarachnoid space in the rat compared favorably to previously reported methods.

6-Cyano-7-nitroquinoxaline-2,3-dione↗

PubMed2000

Changes in echogenicity of spinal subarachnoid space associated with intracranial hemorrhage: new observations.

PURPOSE: The role of subarachnoid blood and secondary, sterile inflammation in the pathogenesis of posthemorrhagic hydrocephalus (PHH) is not well understood. The aims of this study were to study the frequency and rate of spread of blood into the spinal subarachnoid space (SSS) and to evaluate the relationship of this finding and PHH. MATERIALS AND METHODS: Nine premature babies with major intracerebral hemorrhage (ICH, grade 3 or higher), and ten premature infants with minor ICH (grade 1) or no evidence of ICH (control group) were identified and underwent serial cranial and spinal sonography at the time of initial diagnosis, 12-24 h after the ICH and weekly thereafter for at least 9 weeks. Sagittal and axial scans of the thoracolumbar spine were obtained and evaluated for the presence of echogenic debris in the dorsal SSS. Six additional patients who had cranial and spinal sonography died within the 1st week of life and underwent post-mortem examinations. RESULTS: The SSS was echo-free (normal) in all cases at the time of initial sonographic diagnosis of ICH. Within 24 h, all babies with major ICH had developed increased echogenicity of the cervical and thoracic SSS. Echogenicity of the SSS decreased gradually over several weeks. Although transient ventricular dilatation was present in every patient, only one patient had rapidly progressive PHH requiring shunt placement. Transient cysts of the cervicothoracic subarachnoid space were identified in two patients 6-7 weeks after ICH. The subarachnoid space remained echo-free in all control infants At autopsy, all four infants with echogenic spinal debris had blood or blood products in the spinal subarachnoid space, whereas two infants with echo-free spinal images did not. CONCLUSIONS: Spread of blood from the ventricular system into the spinal subarachnoid space after ICH is common and can be seen within 24 h of initial ICH. Subarachnoid blood is associated with post-hemorrhagic ventricular dilatation and transient spinal subarachnoid cyst formation.

Case-Control Studies↗

PubMedDate not supplied

[A study and follow-up of ten cases of benign enlargement of the subarachnoid spaces].

AIM: To present 10 cases with 'benign enlargement of the subarachnoid spaces' and its clinical and image evolution. PATIENTS AND METHODS: We study 10 patients, 7 boys and 3 girls, because of macrocephaly. It was made a clinic and image follow-up from the first year of age to their cure. In the series, there are two monozygotic twins. RESULTS: The patients had normal head circumference centile at birth, and it was 90 or higher at the age of 5 to 12 months, to keep stabilized, without decreasing, during the time of the study despite disappearing enlargement of the subarachnoid spaces. CT and especially magnetic resonance studies, showed the largest subarachnoid spaces and lateral ventricles between 5 and 12 months of age, and then, a slowly decrease to disappear in a period that was variable among the patients. A moderate enlargement was still found after 5 years of age in some cases. The clinic and image follow-up showed a parallel evolution since birth to 5 years in the pair of homozygous twins. Both showed possible reflux of the cerebrospinal fluid from the subarachnoid spaces to the cerebral ventricles, appearing cyst of the septum pellucidum, possibly due to the increase of the intraventricular pressure. The cyst did not disappear and kept the same size despite disappearing the enlargement of the subdural spaces and the normalization of the ventricular size. Psychomotor evolution has been normal, although most of patients show discrete hypotonus and motor coordination problems, attention deficit and/or hyperactivity. CONCLUSION: Benign enlargement of the subarachnoid spaces has a spontaneous solution, but it can carried out in some cases more slowly than it is though. The disease seems hereditary and the most probable etiology is the difficulty in absorption of the cerebrospinal fluid during the first year of life or still longer. The picture, however, always has a spontaneous solution.

Brain↗

PubMed2000

The subarachnoid space: normal fetal development as demonstrated by transvaginal ultrasound.

Enlargement of the subarachnoid spaces can be seen in the following conditions: communicating hydrocephalus, brain atrophy and benign enlargement of the subarachnoid spaces. These disorders may begin in utero. There are no established normograms for the fetal subarachnoid spaces. This study was conducted in order to determine its normal development. Transvaginal sonography was used to examine the subarachnoid space in 80 fetuses between 16 and 40 weeks' gestation. The sinocortical width (SCW) and craniocortical width (CCW) were measured in a coronal plane at the level of the foramen of Monro. The SCW remained relatively constant during the gestational period. The CCW increased in size from the 20th to the 28th week of pregnancy, with a subsequent gradual decrease until term. Determination of fetal subarachnoid space normograms may potentially help in the diagnosis of pathological conditions affecting this space and allow prenatal counselling.

Adult↗

PubMed1992

US measurement of the subarachnoid space in infants: normal values.

The subarachnoid space was examined with real-time ultrasonography (US) in 89 healthy infants. US of the brain in all infants revealed no abnormalities. Three variables were measured in the coronal plane at the level of the foramen of Monro: the sinocortical width (SCW) ranged from 0.4 to 3.3 mm, the craniocortical width (CCW) from 0.3 to 6.3 mm, and the interhemispheric width (IHW) from 0.5 to 8.2 mm. All variables can be used routinely, as the SCW could be demonstrated in all infants, and the CCW and IHW were demonstrated in 96% (85 of 89). Correlation of sonographic measurements with the independent variables age, head circumference, body weight, and body length was poor. To differentiate normal from pathologically dilated subarachnoid spaces, the following upper limits are proposed on the basis of the 95th percentile: 3 mm for SCW, 4 mm for CCW, and 6 mm for IHW.

Female↗

PubMed1997

Noninvasive optical imaging of the subarachnoid space and cerebrospinal fluid pathways based on near-infrared fluorescence.

The authors have developed a noninvasive optical method to image the subarachnoid space and cerebrospinal fluid pathways in vivo based on the near-infrared fluorescence of indocyanine green (ICG). The ICG was bound to purified lipoproteins (ICG-lipoprotein) and injected into the subarachnoid space of neonatal and adult rats. The ICG fluorescence was detected by a cooled charge-coupled device camera. After injection of ICG-lipoprotein into the cerebral subarachnoid space of the neonatal rat, ICG fluorescence was clearly detected at the injection site through the skull and skin. The ICG fluorescence was observed in the cerebellum and the lumbar spinal cord 1 and 8 hours postinjection, respectively. After injection of ICG-lipoprotein into the lumbar spinal subarachnoid space of an adult rat, ICG fluorescence was observed from the injection site to the thoracic levels along the spinal subarachnoid space. In addition, with the rat's head tilted downward, ICG fluorescence had extended to the cerebral subarachnoid space by 1 hour postinjection. The ICG fluorescence imaging of the cerebral subarachnoid space demonstrated an increase in fluorescence intensity around the lambdoid suture and the forebrain. On dissection of the rat brain the former location was identified as the supracerebellar cistern and the latter as the olfactory cistern. The results of this study are the first to demonstrate that an optical technique is applicable to imaging of the subarachnoid space and cerebrospinal fluid pathways in vivo. In addition, ICG-lipoprotein provides a sensitive optical tracer for imaging extravascular biological structures. Finally, ICG fluorescence imaging does not require an intricate imaging system because ICG is localized near the surface of the body.

Animals↗

PubMed1998

Brain tissue pressure gradients are dependent upon a normal spinal subarachnoid space.

Reports from our laboratory have shown that regional brain tissue pressure (RBTP) gradients develop in response to supratentorial but not posterior fossa extradural masses. We undertook this experiment to discover the mechanism of this differing response. RBTP was measured in the right and left frontal lobes (RF, LF), temporal lobes (RT, LT), midbrain (MB), and cerebellum (CB) of ten pigs. Balloons were expanded in the epidural space at C2 to occlude the subarachnoid space. A temporal extradural mass was expanded incrementally. The C2 balloon was deflated after temporal mass expansion. Expansion of the cervical balloon resulted in a homogeneous rise in RBTP. Expansion of the temporal mass resulted in the development of small RBTP gradients with the following relationship: RT > LT = LF > RF = CB > MB. In comparison with a previous series of animals without cervical balloons, animals in this series demonstrated higher global ICP in response to equal size masses and smaller RBTP gradients. Cervical balloon deflation resulted in decreased global ICP and increased RBTP gradients. The development of RBTP gradients in response to expanding supratentorial masses therefore appears to be at least partially dependent upon the presence of a normal communication between the supratentorial space and the spinal subarachnoid space.

Animals↗

PubMed1992

Follow-up study of macrocephalic children with enlargement of the subarachnoid space.

Eighteen macrocephalic children with enlargement of the subarachnoid space (ESAS), with or without mild ventricular dilatation, were followed prospectively to a mean age of 56 months. All were born at term, with uneventful neonatal period and negative tests for congenital infections. There were 17 boys and 1 girl and the mean follow-up period was 46 months (8-58 months). The initial neurologic evaluation, between ages of 2 to 33 months, disclosed abnormalities in 2 cases. At the follow-up one was still abnormal and the other had a normal neurological examination. Another child, who had a normal neurological examination at the age of 5 months, at the age of 7 years and 7 months had an IQ of 77. Thus the abnormality rate at follow-up was 11%. The OFC returned to the normal range in 45% of the children at the follow-up period. There were no cases of intracranial hypertension. One infant had subdural taps performed at the age of 13 months that disclosed a fluid with the same characteristics as the CSF. All the children had a CT-scan performed at the beginning of the study that revealed a large subarachnoid space; in 77% it was associated with mild ventricular dilatation. Eleven had CT-scans repeated, during the study period, which showed resolution of the process in 3 cases, improvement in 2, and unchanged in 6. We conclude that enlargement of the subarachnoid space in macrocephalic children is often a benign entity. ESAS and macrocephaly will still be present in the majority of children in the long-term follow-up.

Child↗

PubMed1996

High-resolution magnetic resonance imaging of the intraorbital optic nerve and subarachnoid space in patients with papilledema and optic atrophy.

OBJECTIVE: To evaluate the orbital portion of the optic nerve and the subarachnoid space using fast spin-echo magnetic resonance imaging in normal subjects and in patients with papilledema or optic atrophy. DESIGN: Measurements of the optic nerve complex on coronal images were made using high-resolution magnetic resonance imaging with fast spin-echo sequences. PATIENTS: Twenty-one patients, including 5 patients with papilledema due to congenital hydrocephalus, intracranial tumors, or meningitis, as well as 16 patients with optic atrophy, were studied. Sixteen healthy volunteers served as controls. MAIN OUTCOME MEASURES: The longitudinal diameter of the optic nerve, the longitudinal outer diameter of the subarachnoid space, the diameter ratio, and the area of the subarachnoid space were determined. RESULTS: In normal subjects, the ring-shaped area of high signal intensity that represented the subarachnoid space was widest behind the globe, then narrowed toward the orbital apex. In patients with papilledema, the area of the subarachnoid space was markedly dilated, the optic nerve was compressed, and the nerve sheath was widened, resulting in a small diameter ratio compared with that of controls. Patients with pallor of the temporal aspect of the optic disc appeared to exhibit dilation of the subarachnoid space; the size of the optic nerve was decreased more than that of the nerve sheath, resulting in a small diameter ratio compared with controls. Patients with complete pallor of the disc, however, exhibited hyperintense optic nerve complexes without a ring-shaped appearance toward the orbital apex. CONCLUSION: Fast spin-echo magnetic resonance imaging appears useful for objectively evaluating the optic nerve and surrounding subarachnoid space in patients with papilledema and optic atrophy.

Adolescent↗

PubMed1992

The subarachnoid spaces in craniosynostosis.

A review of 85 patients with various forms of craniosynostosis showed predictable patterns of dilatation of the subarachnoid spaces in regions of compensatory skull growth. The characteristic pattern in sagittal synostosis (43 patients) included dilatation of the frontal and occipital subarachnoid spaces associated with the elongation of the anteroposterior dimension of the skull and widening of the interhemispheric fissure. In 11 patients with unilateral coronal synostosis, dilatations of the subarachnoid spaces over the contralateral frontal lobe, the sylvian regions, and the ipsilateral temporal lobe tip were consistent with the skull changes of contralateral frontal bossing, increased bitemporal dimension, and elevation of the sphenoid wing, respectively. Four patients with bilateral coronal synostosis also had enlarged subarachnoid spaces high over the convexities of the brain consistent with the towering configuration of the skull. Four patients with true lambdoid synostosis had dilatation of the subarachnoid space only over the ipsilateral frontal lobe associated with compensatory bossing of the frontal bone. Ten of 14 patients with lambdoid deformities had bilateral enlargement of the subarachnoid spaces suggesting brain atrophy and an underlying motor delay accounting for the position-induced skull changes. The findings suggest that focal hydrodynamic mechanisms are involved in the compensatory skull changes seen in craniosynostosis.

Atrophy↗

PubMed1979

Scanning electron microscopy of the subarachnoid space in the dog: evidence for a non-hematogenous origin of subarachnoid macrophages.

Injection of viable BCG into the subarachnoid space of immunized and non-immunized dogs produced a 10-fold increase in the populations of pial free cells. In immunized animals injected three days previously with BCG, stereoscopic SEM revealed that many pial cells had rounded up and were protruding into the subarachnoid space. With continued rounding these cells took on amoeboid characteristics, with shapes that suggested a capacity for cell movement. Internally, these pial cells possessed an increased volume of perinuclear cytoplasm and organelles. Reactive pial cells could be distinguished from macrophages of presumed hematogenous origin on the basis of their surface morphology. These findings suggested that pial cells had the ability to alter their normal structural and behavioral characteristics and to become macrophage-like under these conditions of secondary challenge by BCG.

Animals↗

PubMedDate not supplied

Continuous pump pressures cannot be used to identify catheter tip migration into the subarachnoid space.

BACKGROUND AND OBJECTIVES: Migration of an epidural catheter into the subarachnoid space is a potentially lethal complication of continuous epidural anesthesia. We evaluated the use of pump pressure measurement during infusion in detecting such an occurrence. METHODS: Pump pressures at two flow rates (P1 and P10) and epidural space pressure (P0) were measured hourly in eight consecutive ASA Physical Status I parturients receiving continuous epidural anesthesia and compared to those of a patient whose catheter migrated into the subarachnoid space. In addition, total resistance to infusion (Rtot) was calculated as the slope of the least squares regression line linking pressure and flow. Epidural resistance (Repi) was computed as the difference between total resistance and catheter resistance; Repi = Rtot - Rcath. RESULTS: In epidural catheters, average P0 and P10 were 13 +/- 4 mmHg and 23 +/- 4 mm Hg, respectively, and did not change over time. Rtot and Repi averaged 960 +/- 180 RU and 980 +/- 120 RU, respectively. Pump pressures in the subarachnoid catheter were 10 mmHg for P0 and 20 mmHg for P10, while Rtot was 1000 RU. CONCLUSIONS: We conclude that epidural and subarachnoid space resistance is essentially zero and the pump pressure in the system is used to overcome the catheter resistance. Both spaces offer the same total resistance to infusion and, therefore, pump pressure will not change when a catheter migrates into the subarachnoid space.

Anesthesia, Epidural↗

PubMed2003

Architecture of arachnoid trabeculae, pillars, and septa in the subarachnoid space of the human optic nerve: anatomy and clinical considerations.

AIMS: To describe the anatomy and the arrangement of the arachnoid trabeculae, pillars, and septa in the subarachnoid space of the human optic nerve and to consider their possible clinical relevance for cerebrospinal fluid dynamics and fluid pressure in the subarachnoid space of the human optic nerve. METHODS: Postmortem study with a total of 12 optic nerves harvested from nine subjects without ocular disease. All optic nerves used in this study were obtained no later than 7 hours after death, following qualified consent for necropsy. The study was performed with transmission (TEM) and scanning electron microscopy (SEM). RESULTS: The subarachnoid space of the human optic nerve contains a variety of trabeculae, septa, and stout pillars that are arranged between the arachnoid and the pia layers of the meninges of the nerve. They display a considerable numeric and structural variability depending on their location within the different portions of the optic nerve. In the bulbar segment (ampulla), adjacent to the globe, a dense and highly ramified meshwork of delicate trabeculae is arranged in a reticular fashion. Between the arachnoid trabeculae, interconnecting velum-like processes are observed. In the mid-orbital segment of the orbital portion, the subarachnoid space is subdivided, and can appear even loosely chambered by broad trabeculae and velum-like septa at some locations. In the intracanalicular segment additionally, few stout pillars and single round trabeculae are observed. CONCLUSION: The subarachnoid space of the human optic nerve is not a homogeneous and anatomically empty chamber filled with cerebrospinal fluid, but it contains a complex system of arachnoid trabeculae and septa that divide the subarachnoid space. The trabeculae, septa, and pillars, as well as their arrangement described in this study, may have a role in the cerebrospinal fluid dynamics between the subarachnoid space of the optic nerve and the chiasmal cistern and may contribute to the understanding of the pathophysiology of asymmetric and unilateral papilloedema. All the structures described are of such delicate character that they can not even be visualised with high resolution magnetic resonance imaging (MRI).

Arachnoid↗

PubMed1998

Biomechanical aspects of the subarachnoid space and cervical cord in healthy individuals examined with kinematic magnetic resonance imaging.

STUDY DESIGN: In vivo flexion-extension magnetic resonance imaging studies of the cervical spine were performed inside a positioning device. OBJECTIVE: To determine the functional changes of the cervical cord and the subarachnoid space that occur during flexion and extension of the cervical spine in healthy individuals. SUMMARY OF BACKGROUND DATA: As an addition to static magnetic resonance imaging examinations, kinematic magnetic resonance imaging studies of the cervical spine were performed to obtain detailed information about functional aspects of the cervical cord and the subarachnoid space. The results were compared with published data of functional flexion-extension myelograms of the cervical spine. METHODS: The cervical spines of 40 healthy individuals were examined in a whole-body magnetic resonance scanner from 50 degrees of flexion to 30 degrees of extension, using a positioning device. At nine different angle positions, sagittal T1-weighted spin-echo sequences were obtained. The images were analyzed with respect to the segmental motion, the diameter of the subarachnoid space, and the diameter of the cervical cord. RESULTS: The segmental motion between flexion and extension was 11 degrees at C2-C3, 12 degrees at C3-C4, 15 degrees at C4-C5, 19 degrees at C5-C6, and 20 degrees at C6-C7. At flexion, a narrowing of the ventral subarachnoid space of up to 43% and a widening of the dorsal subarachnoid space of up to 89% (compared with the neutral position, 0 degrees) were observed. At extension, an increase in the diameter of the ventral subarachnoid space of up to 9% was observed, whereas the dorsal subarachnoid space was reduced to 17%. At flexion, there was a reduction in the sagittal diameter of the cervical cord of up to 14%, and, at extension, there was an increase of up to 15%, compared with the neutral position (0 degrees; these values varied depending on the cervical segment. Statistically significant differences (P < 0.05) were found between flexion and extension in the diameter of the ventral and dorsal subarachnoid space and in the diameter of the cervical cord. CONCLUSIONS: Compared with the results of previous studies using functional cervical myelograms, kinematic magnetic resonance imaging provides additional noninvasive data concerning the physiologic changes of the cervical subarachnoid space and the cervical cord during flexion and extension in healthy individuals.

Adult↗

PubMed2004

Enhanced antinociception by nicotinic receptor agonist epibatidine and adrenal medullary transplants in the spinal subarachnoid space.

Adrenal medullary transplants in the spinal subarachnoid space can reduce nociception, via the release of catecholamines and other analgesic substances, and this may be enhanced by stimulation of transplanted chromaffin cell surface nicotinic acetylcholine receptors (nAChRs). In addition, spinal nAChRs have been implicated in modulating nociception and can interact synergistically with alpha-adrenergic agents. Thus, enhanced antinociception by potent nAChR agonists such as frog skin derivative epibatidine in adrenal-transplanted animals could potentially occur via multiple mechanisms, including nicotinic-alpha-adrenergic synergy and stimulation of chromaffin cell nicotinic receptors. In order to test this, male Sprague-Dawley rats were implanted with intrathecal catheters and either adrenal medullary or control striated muscle transplants in the spinal subarachnoid space at the lumbar enlargement. Animals were tested for nociceptive responses before and after intrathecal injection of several doses of epibatidine using acute analgesiometric tests (tail flick, paw pressure) and the formalin test. After adrenal medullary, but not control, transplantation, nociceptive thresholds to acute noxious stimuli were slightly but consistently elevated, and phase 2 formalin responses decreased. Following intrathecal injection of epibatidine, acute nociceptive response latencies were modestly elevated and phase 2 formalin flinches modestly suppressed in control animals, but only at the highest dose test, with some attendant motor side-effects. In contrast, in adrenal medullary-transplanted animals, epibatidine elevated responses to acute noxious stimuli and markedly suppressed phase 2 formalin responses in a dose-related fashion. The enhanced antinociceptive effect following epibatidine was attenuated with either nAChR antagonist mecamylamine or alpha-adrenergic receptor antagonist phentolamine. The current results demonstrate that intrathecal injection of the nAChR ligand epibatidine can produce significant antinociception in adrenal-transplanted rats in both acute and tonic nociceptive tests and suggest that the use of nicotinic agents in combination with adrenal medullary transplantation could provide maximal therapeutic benefit by synergistically improving antinociception while avoiding the detrimental side-effects of these agents.

Adrenal Medulla↗

PubMed1983

The subarachnoid spaces in children: normal variations in size.

Intra- and extraventricular subarachnoid spaces in children were studied by high-resolution computed tomography. Scans were reviewed of 34 patients who were selected as highly likely to have normal scans. Sizes of the ventricular system and the seven extraventricular subarachnoid compartments were analyzed and graded on a subjective scale from 0 (not visible) to 4 (markedly enlarged). Data were also analyzed by age group (greater or less than 2 years of age). The subarachnoid spaces were found to be both larger and more variable in size before the age of 2 years and to be quite uniform thereafter. Based on these findings, it is inadvisable to base specific diagnoses during the first 2 years of life solely upon modest enlargement of the subarachnoid spaces.

Age Factors↗

PubMed1994

Extracerebral fluid collections in infancy: role of magnetic resonance imaging in differentiation between subdural effusion and subarachnoid space enlargement.

The pathological process of extracerebral fluid collections in infancy includes subdural effusion and enlargement of the subarachnoid spaces. Both conditions have traditionally been investigated as a single clinical entity, because of difficulty in differentiating between them. The prognosis of subdural effusion is not as benign as that of enlargement of subarachnoid spaces, requiring differential diagnosis between these disorders. The present study was conducted to elucidate whether this differentiation could be made on magnetic resonance (MR) images. The series consisted of 16 infants aged 10 months or younger, including eight with verified subdural effusion and eight in whom a diagnosis of enlargement of the subarachnoid spaces was achieved by neuroimaging studies other than MR imaging. In all eight patients with subdural effusion, the intensity of the fluid was greater than that of cerebrospinal fluid (CSF) in at least one of the sequences using T1-weighted, proton-density, and T2-weighted MR images. The flow-void sign, indicating vessels in the fluid spaces, was not seen in any of these eight patients. On the other hand, in all eight patients with enlargement of the subarachnoid spaces, the fluid was isointense in relation to CSF, and vascular flow-void areas were seen in at least one of the MR imaging sequences. Based on these observations, it is concluded that differentiation between subdural effusion and enlargement of the subarachnoid spaces can be established by focusing on two aspects of MR imaging findings: 1) the intensity of the fluid, which is either iso- or hyperintense relative to CSF, and 2) the presence or absence of vascular flow-void areas in the fluid spaces.

Contrast Media↗