椎管内硬脊膜外蛛网膜囊肿的低场强MRI诊断

目的:探讨椎管内硬脊膜外蛛网膜囊肿的低场强MRI表现特征,提高对该病的认识。方法:回顾性分析12例经手术病理证实的硬脊膜外蛛网膜囊肿的临床及MRI表现特征,其中10例行Gd DTPA增强扫描,7例行X光平片或CT片检查。结果:本组病例发病于胸腰段8例,位于脊髓背侧9例,呈典型的椎管内硬脊膜外占位病变征象,囊肿的信号强度与脑脊液一致或相近,上、下缘与硬脊膜外脂肪毗邻,上或下方邻近硬脊膜的显示,可为硬脊膜外囊肿的定位诊断提供有力的佐证,囊肿与蛛网膜下腔相交通时,孔道区囊肿内可出现流空信号,可确定孔道的具体位置,为手术提供可靠可靠的依据。结论:MRI是目前评价椎管内硬脊膜外蛛网膜囊肿的定位和定性诊断最佳影像学方法和首选检查手段。     

Imaging of large Rathke's cleft cysts by CT and MRI: report of two cases

Two patients with large Rathke's cleft cysts in the sella turcica and suprasellar region presented with visual impairment and hypopituitarism. The entirely different CT and MRI appearances of the two cysts were thought to depend principally on the protein content of the cyst fluid.     

Thoracic spinal intradural arachnoid cyst: report of two cases and review of literature

We report two cases of spinal intradural arachnoid cyst at the thoracic level, presenting with long-standing symptoms of spinal cord compression and MRI findings that were overlooked for sometime initially. Because of the rarity of this disease, and because of the subtle changes on MRI, there was a definite delay in the diagnosis. In this report we emphasize the value of MRI and CT myelography in this disorder, and the need for them to be strongly correlated with the progression of the clinical picture.     

Intracranial arachnoid cysts in myotonic dystrophy

Summary Clinically apparent brain dysfunction is common in myotonic dystrophy. In a sample of fourteen adult patients with the definite form of this disease, brain magnetic resonance imaging detected frequent white matter abnormalities and ventriculomegaly. In addition, two patients exhibited an intracranial arachnoid cyst, a condition of neurosurgical interest that could be related to the generalized dysmaturational process present in this disease. Patients with myotonic dystrophy deserve a careful screening for brain involvement. Further MRI studies should ascertain the actual prevalence of brain anomalies in myotonic dystrophy and define the role of this procedure in the workup of this disease.     

Dynamic study of arachnoid cysts with metrizamide

Summary Intracranial arachnoid cysts do not usually present diagnostic problems when studied by CT, since they appear as low density images similar to those produced by CSF, do not change on intravenous contrast perfusion, and are located extraparenchymatously. Sometimes, however, their diagnosis can become difficult or doubtful mainly in cases of deep, basal or paramedian cysts [12, 18, 22, 24]. on the other hand, the functional or dynamic aspects of these structures remain unkown when the study is limited to simple CT. Computed cysternography with metrizamide (CCM) and time control will not only show the relationship between these structures and the arachnoid space but also their dynamic aspect, which may determine the surgical treatment.     

The MRI signs of spinal arachnoid diverticula

Our goal was to find MRI signs of use for identifying a spinal arachnoid diverticulum. Three cases of spinal arachnoid diverticula, one extradural and two intradural, were examined on a 1.5 T imager. There was obvious mass effect on the adjacent structures in one case and increased signal intensity in the diverticulum on proton density- and T2-weighted images in two cases. Signal changes due to turbulent movement of the spinal fluid inside the diverticula were seen in all cases on sagittal fast spin-echo (FSE) proton density- and T2-weighted images; it was difficult to tell whether these signal changes imply a communication or are simply FSE artefacts. On contrast-enhanced studies, all cases showed partial enhancement inside the diverticula. There thus are four signs of diverticula: mass effect, the increased signal, signal void sign and partial enhancement; the last of these, the most reliable, has never been reported before. Received: 22 December 1995 Accepted: 26 July 1996     

Arachnoid cysts of the middle cranial fossa: a consideration of their origins based on imaging

Arachnoid cysts situated in the middle cranial fossa constitute the largest group of this type of lesion. Their origin has been the subject of debate since they were first described. There is still controversy as to whether they originate directly from the meninges adjacent to the temporal pole or whether partial agenesis of the temporal lobe favours secondary formation of the cyst. We assessed the morphology of the temporal lobe and the bulging of the squamous temporal bone. Paradoxical changes in adjacent-bone, described as very rare findings in arachnoid cysts of the middle cranial fossa, were common in our study and suggest, in association with direct signs of temporal atrophy, that this atrophy precedes, or is at least coexistent with, the formation of the cyst. The importance of being able to determine the origin of the cyst lies in its being a factor to assess as regards treatment.     

Imaging of spinal intradural arachnoid cysts: MRI, myelography and CT

Imaging studies in eight patients with surgically-confirmed spinal arachnoid cysts were analyzed retrospectively. All patients had preoperative MRI of the spine and seven preoperative myelography with postmyelographic CT. In all cases the correct diagnosis could be made preoperatively on the basis solely of MRI. The diagnosis could also be established from myelography and postmyelographic CT in six of the seven cases. In one case myelography and CT simply demonstrated an intradural extramedullary mass. Received: 30 December 1997 Accepted: 18 February 1998     

Intramedullary schwannoma of the spinal cord: report of two cases

We report magnetic resonance findings in the intramedullary schwannoma of the cervical spinal cord in two patients. In both cases, the solid portions of the tumours enhanced intensely after administration of Gd-DTPA and the enhanced border was sharply delineated from the adjacent spinal cord. Schwannomas should be considered in the differential diagnosis of intramedullary tumours when magnetic resonance images show a strongly enhancing mass with sharply delineated borders. Received: 8 September 2000 Accepted: 9 November 2000     

Magnetic resonance imaging of arachnoid cysts

A retrospective review of magnetic resonance imaging (MRI)—computed tomography (CT) correlation was performed in 29 patients with arachnoid cysts. Short TR, short TE spin echo (SE) pulse sequences provided the best anatomic definition whereas multiple echo long TR, TE sequences allowed comparison of the signal intensity of the cyst with that of cerebrospinal fluid (CSF). Simple arachnoid cysts were isointense while neoplastic, hemorrhagic or inflammatory cysts were hyperintense relative to CSF. The CT differential diagnosis of an arachnoid cyst (depending upon its location) may include other cystic collections such as craniopharyngioma, epidermoid, astrocytoma, and chronic subdural hematoma. However, on MRI the combination of extraaxial location, morphological features, and signal intensity matching that of CSF allows one to make the diagnosis of an uncomplicated arachnoid cyst with confidence.     

Myelographic and MRI appearances of a thoracic spinal extradural arachnoid cyst of the spine with extra-and intraspinal extension

Summary An unusual arachnoid, cyst of the thoracic spine is reported. The clinical and neuroradiological features are described.     

Contrast-enhanced MRI of intrasellar arachnoid cysts: relationship between the pituitary gland and cyst

We recently encountered two large intrasellar arachnoid cysts extending to the suprasellar region. The intensity of the cyst contents was identical to that of the cerebrospinal fluid on both T1- and T2-weighted MRI. On contrast-enhanced MRI, the pituitary gland was compressed posteroinferiorly and flattened in the sella turcica. In this report of rare intrasellar arachnoid cysts the discussion is focused on dislocation of the pituitary gland.     

Imaging of spinal cord compression due to thoracic extramedullary haematopoiesis in myelofibrosis

We describe a case of spinal cord compression secondary to extramedullary haematopoiesis in a patient with primary myelofibrosis. We show that MRI should be the procedure of choice for patients suspected of this condition. Furthermore, it could be of value for assessing the extent of cord compression, planning radiotherapy and for follow-up. Received: 13 May 1996 Accepted: 24 October 1996     

Giant arachnoid granulation mimicking dural sinus thrombosis in a boy with headache: MRI

We report MRI and angiographic findings of an unusual giant arachnoid granulation in the left sigmoid sinus in a boy with headache. Its signal intensity was lower than that of cerebral cortex on T1-weighted images and higher on T2 weighting, mimicking dural sinus thrombosis. Received: 17 February 1997 Accepted: 17 February 1997     

Idiopathic dural herniation of the thoracic spinal cord

Symptomatic anterior or anterolateral dural herniation of the spinal cord is rare, and not uncommonly misdiagnosed, both clinically and radiologically. We present four patients with a radiological diagnosis of herniation of the thoracic spinal cord, and review the current literature. All affected patients have been adults, typically presenting with long-standing, unexplained sensory symptoms and eventually developing a Brown-Séquard syndrome, with or without motor changes. Herniation occurs in the upper or midthoracic region, between the T2 and T8 levels.     

Magnetic resonance imaging contribution to the diagnosis of spinal cord compression by a subdural arachnoid cyst

Summary A case of subdural arachnoid cyst of the thoracic spine was studied by magnetic resonance imaging (MRI), myelography and CT myelography. Myelography and especially CT myelography suggested the diagnosis; MRI established it, showing the communication between the cyst and the subarachnoid space. Final characterization was based on surgical findings and pathological examination.     

Neuroradiological examination of thoracic radiculo-myelopathy due to ossification of the ligamentum flavum

Summary Sixteen cases of thoracic radiculomyelopathy due to ossification of the ligamentum flavum (OLF) were analyzed. The patients ranged in age from 39 to 78 years (average 57 years). There were 13 men and 3 women. A significant predilection of OLF for the lower thoracic spine (T9/10, T10/11, T11/12) was noticed. Plain X-ray of the thoracic spine and multidirectional tomography could give important information about the site of ossification. Computed tomography with the intrathecal injection of the water-soluble contrast material clearly demonstrated the ossification and the degree of compression of the spinal cord. The disadvantages of using computed tomography for diagnosing OLF included the necessity for the scan level to be previously decided by other methods because computed tomography of the entire spine was impractical. Magnetic resonance imaging was performed in 14 patients and gave important information about OLF and the compression of the spinal cord. The combination of MRI and computed tomography seems the most useful for the precise diagnosis of OLF.     

Cavernous hemangioma of the thoracic spinal cord

Summary A 25-year-old woman presented with a four-year history of progressive right-lower-extremity weakness and atrophy and a left hemisensory deficit was found. Metrizamide-enhanced spinal CT scan showed an intramedullary lesion at the level of T1-T2; this had expanded the cord in fusiform fashion but showed no evidence of a cystic component. Surgical resection was performed and the pathological diagnosis was cavernous hemangioma. Two and one-half years later, her left hemisensory deficit was worsening and a spinal MRI showed high signal intensity mass in the region of the previous surgery consistent with chronic hematoma which was re-evacuated with some improvement in the patient's neurological condition.     

Ruptured spinal dermoid cyst with chemical arachnoiditis and disseminated intracranial lipid droplets

A 33-year-old man presented with a 3-month history of gradually progressive leg weakness. Spinal MRI and myelography with CT demonstrated an extensive intradural abnormality suggesting a diffuse inflammatory or neoplastic process. Only after cranial CT and MRI demonstrated lipid droplets was the diagnosis of a ruptured spinal dermoid cyst suggested. Subsequent laminectomy revealed a ruptured intradural dermoid cyst in the lumbar spine, with chemical arachnoiditis.