The MR appearance of CSF pulsations in the spinal canal

We investigated the MR appearance and incidence of low-signal areas within the CSF of the spinal canal. Nonuniform areas of decreased signal intensity in intracranial CSF have been named the CSF flow-void sign (CFVS) and appear to be due to spin dephasing secondary to pulsatile CSF motion. Similar areas are seen in the spinal canal. The MR scans of 50 randomly selected patients, constituting a total of 63 spinal studies, were reviewed. There were 27 cervical, 16 thoracic, and 20 lumbar spine examinations. All patients were studied using T2-weighted and T1-weighted spin-echo pulse sequences. T2-weighted images were done with sufficiently long TE and TR to cause the CSF to appear hyperintense compared with brain and spinal cord tissue. Two patients with enlarged spinal canals and two patients with syringohydromyelia were also included to illustrate the appearance of prominent CSF pulsations. The CFVS was identified on T2-weighted scans in the cervical spinal canal in nine patients (33%), in the thoracic spinal canal in one patient (6%), and possibly in the lumbar spinal canal in two patients (10%). The CFVS was prominent in two patients with enlarged CSF spaces and was also seen in the intramedullary cavity of the patients with syringohydromyelia. The CFVS could obscure small dural lesions and, in some instances, simulate enlarged vessels. Recognition of the spinal CFVS is important to avoid the incorrect diagnosis of intraspinal lesions.     

卵巢囊肿与非肿瘤性囊性病变的MRI表现

MRI对于盆腔良性病变的诊断及盆腔内良、恶性肿物的鉴别具有重要价值。介绍了正常卵巢的MRI解剖、各种卵巢囊肿与非肿瘤性卵巢囊性病变的MRI表现,提出了卵巢囊肿的MRI诊断和进一步诊疗原则。     

卵巢囊肿与非肿瘤性囊性病变的MRI表现

MRI对于盆腔良性病变的诊断及盆腔内良、恶性肿物的鉴别具有重要价值。介绍了正常卵巢的MRI解剖、各种卵巢囊肿与非肿瘤性卵巢囊性病变的MRI表现,提出了卵巢囊肿的MRI诊断和进一步诊疗原则。     

Ambiguities in MR imaging of tumoral cysts in the spinal cord

We describe two cases in which the magnetic resonance (MR) imaging characteristics of tumors of the spinal cord were ambiguous. Both cases were primary low-grade astrocytomas that had had previous surgery. In the first case the findings were indeterminate as to whether the lesion was solid, cystic with proteinaceous fluid, or mixed. Intraoperative ultrasound demonstrated large cystic areas with an associated solid mass. In the second case MR was reported as cystic with a solid nodule. Ultrasonography demonstrated an almost entirely solid mass with a localized cyst corresponding to the presumed solid area. In both of these cases, but especially the latter, the localization of cysts within the lesions was of vital importance to therapy.     

Percutaneous injection of metrizamide into spinal cord cysts for preoperative diagnosis of syringomyelia

Five cases of syringomyelia are reported in which the spinal cysts were percutaneously punctured and filled with metrizamide for preoperative diagnosis. There were no side effects from the puncture or the contrast medium. In all cases the cyst was larger than had been demonstrated by previous myelography. A communication to the fourth ventricle was seen in two cases. Four patients had surgical treatment; the neurologic deficits improved in two patients, while the condition of the others has remained unchanged.     

Intramedullary spinal cord tumors: MR imaging, with emphasis on associated cysts

Fifteen magnetic resonance (MR) imaging studies in 16 patients with intramedullary spinal cord lesions were correlated with surgical findings in all patients and with results of intraoperative spinal sonography (IOSS) in eight. Tumor extent was defined accurately in all but two patients by MR imaging; these lesions were found at surgery to have been underestimated by one to two vertebral body segments. Most tumors had lengthened T1 and T2 relaxation times. Intratumoral cysts were detected by MR imaging in one of eight cases, and rostral and caudal cysts were defined in only two of ten cases. The poor detection rate is attributed to poor spatial and contrast resolution. Preoperative MR imaging to define the extent of cord enlargement and IOSS to define cystic structures appears to be the optimal method of tumor management pending our further study.     

Differentiation of suprasellar nonneoplastic cysts from cystic neoplasms by Gd-DTPA MRI.

Magnetic resonance imaging in 9 cases of surgically confirmed nonneoplastic intra- and/or suprasellar cysts was analyzed and compared with that from 17 cases of craniopharyngioma and 12 of cystic pituitary adenoma. Signal intensity did not help in distinguishing nonneoplastic cysts from cystic neoplasms. No postcontrast (Gd-DTPA) cyst wall enhancement was observed among the nonneoplastic cysts, although all 6 craniopharyngiomas and 12 cystic pituitary adenomas that underwent postcontrast study did enhance. Three nonneoplastic cysts were surrounded by the pituitary gland, thus mimicking wall enhancement in the postcontrast studies. Rapid enhancement in the early postcontrast-administration phase (dynamic studies) helped avoid confusion between the normal pituitary tissue and cyst wall enhancement. Magnetic resonance studies with contrast enhancement play an essential role in differentiating nonneoplastic cysts from cystic neoplasms in the sella region.     

Intraoperative spinal sonography: adjunct to metrizamide CT in the assessment and surgical decompression of posttraumatic spinal cord cysts

Ten patients with prior spinal cord trauma were examined preoperatively by metrizamide computed tomography (CT) and were studied subsequently by intraoperative spinal sonography. On comparing intraoperative sonography with metrizamide CT, it was found that metrizamide CT tends to overestimate the size and number of posttraumatic cysts, that areas of myelomalacia on metrizamide CT correspond to areas of abnormal echogenicity on intraoperative sonography, and that intracyst septations are seen only on intraoperative sonography. By monitoring the position of the shunting catheter during surgery, intraoperative sonography can assure its proper intramedullary placement and demonstrate the successful decompression of the cyst. If no cyst is found with intraoperative sonography, further surgery is obviated. Intraoperative sonography is recommended for all cases where decompression of cord cysts is planned.     

Ex vivo evaluation of ADC values within spinal cord white matter tracts

BACKGROUND AND PURPOSE: Our purpose was to evaluate the effect of fixative on apparent diffusion coefficient (ADC) values and anisotropy within spinal cord white matter. As glutaraldehyde (GL) better preserves axonal ultrastructure as compared with paraformaldehyde (PF), we hypothesize that spinal cord white matter fixed with GL will have increased anisotropic water diffusion as compared with specimens fixed with PF. METHODS: Eleven rats were perfusion-fixed with either 4% PF or a combination of 2.5% GL and 4% PF. Diffusion-weighted imaging of the ex vivo spinal cord was performed using a 9.4T magnet with b values up to 3100 s/mm(2). In-plane resolution was 39 mum x 39 mum, and section thickness was 500 mum. RESULTS: Overall, animals fixed with a combination of GL and PF (GL-PF) showed a greater increase in longitudinal ADC (lADC) as compared to those fixed with PF only, without differences in transverse ADC (tADC). As a consequence of the increased lADC, overall anisotropic diffusion increased in those animals fixed with GL-PF, as measured with an anisotropy index (AI = tADC/lADC). Evaluation of specific tracts demonstrated that lADC for animals fixed with GL-PF were significantly elevated in the rubrospinal, vestibulospinal, and reticulospinal tracts as compared with animals fixed with PF only. CONCLUSION: Using a fixative of GL-PL results in increased anisotropy (decreased AI values) in spinal cord white matter tracts, as compared with PF fixation only, largely owing to increases in the lADC values. This finding may be due to better fixation of intra-axonal cytoskeletal proteins that results when GL is combined with PF and sheds further light on underlying sources of anisotropic water diffusion in CNS white matter.     

First-trimester umbilical cord cysts.

Cystic masses of the umbilical cord have been detected in the 2nd and 3rd trimesters of pregnancy in association with fetal abdominal wall defects and chromosomal anomalies. With high-resolution endovaginal ultrasound (US), umbilical cord cysts can be visualized during the 1st trimester. Their origin and significance must be considered for proper obstetric management. The authors report eight cases in which cystic masses of the umbilical cord were detected during US examinations performed at 8-9 weeks menstrual age. In the five cases followed to term, both the infant and the umbilical cord were found to be normal at physical examination. Sonographically, all cysts appeared to be eccentric in relation to the umbilical cord, and, although all were closer to the fetus, the cysts were clearly extraembryonic. Cyst size was 2.0-7.5 mm (mean, 5.2 mm). Seven cysts resolved by 12 weeks menstrual age. The incidence of cysts in patients who underwent US at the authors' institution between 8 and 12 weeks menstrual age was 0.4%; the true frequency is unknown without routine 1st-trimester scanning of all patients.     

组织工程脊髓修复脊髓损伤的研究进展

脊髓损伤可以导致损伤平面以下神经功能的破坏性丢失,严重地影响身体多个系统.脊髓损伤的效应随着损伤部位不同而不同,这是脊神经有序地按照脊髓排列的缘故.除了损伤平面以下运动功能受损,同时还伴有感觉异常.其造成的功能缺陷包括心血管系统功能、呼吸系统功能、胃肠道消化功能、排汗功能、性功能以及排尿功能,这些缺陷可继发泌尿系感染、褥疮、肌肉痉挛、慢性神经性疼痛和感觉异常等,更严重的可致命.因此,脊髓损伤成为人类急需解决的医学难题之一,至今仍困扰着无数医学工作者。     

Suprasellar arachnoid cysts: 2. Evaluation of CSF dynamics

Suprasellar arachnoid cysts are an infrequent but surgically remediable cause of hydrocephalus and neurologic deficits. The optimal method of treatment varies according to whether the cyst communicates with the subarachnoid space; the presence or absence of associated hydrocephalus; and the exact site(s) and severity of intraventricular and extraventricular cerebrospinal fluid (CSF) obstruction. Eight patients with suprasellar arachnoid cysts are described to emphasize the importance of pretherapeutic investigation of CSF dynamics. The variability of the ventriculocisternal-cyst CSF dynamics and the value of metrizamide computed tomographic cisternography and ventriculography in investigation of the CSF pathways are stressed. A diagnostic approach to the evaluation of the CSF dynamics is outlined, based on whether hydrocephalic or compressive symptoms predominate.     

Congenital spinal intradural and extradural cysts

Two intradural and two extradural spinal cysts are reported. The authors compare these cases with others reported in the literature. They agree about the dorsal retromedullary site but they disagree about the age and sex. Although the cysts have been opacified only in two cases, the myelographic diagnosis was easy in every case except one. The myelo-CT is'nt necessary for diagnosis but it offers a better visualization of the relation between the lesion and the spinal cord.     

Malignant spinal cord compression

Back pain is a common affliction which usually does not require imaging. However there are instances when imaging is not only appropriate but essential and must be performed urgently. This article uses a case study to illustrate why patients presenting with back pain and loss of normal gait and sphincter control require urgent magnetic resonance imaging of the whole spine.