纵裂池出血的CT诊断

目的　提高即时纵裂池出血的CT诊断能力。方法　搜集经 2次以上颅脑CT检查能确诊的纵裂池出血 6 3例。另按顺序取自我科颅脑CT检查正常者 15 0例做对比资料。按Zimmerman等提法 ,将大脑镰及纵裂池以胼胝体为界分为上、前、后三部分作分析。结果　纵裂池出血表现为 :纵裂池线影增宽、密度增高 ;前纵裂池线影增长 ;侧脑室上方 10mm层面纵裂池内高密度线影前后连贯 ;纵裂池内高密度“之”字征 ;天幕切迹增宽。结论　上述结果是诊断纵裂池出血的重要CT征象。     

非常见部位急性硬膜下血肿CT诊断(附26例报告)

目的　提高对非常见部位急性硬膜下血肿CT表现的认识。方法　头颅外伤后在 2 4h内行CT检查 1 9例 ,2～ 3d内行CT检查 7例。经治疗后在 1～ 4周内复查CT。结果　单纯表现为大脑镰急性硬膜下血肿 7例 ,小脑幕急性硬膜下血肿 5例。额颞底部急性硬膜下血肿 2例。脑挫裂伤、脑内血肿伴有大脑镰急性硬膜下血肿 3例 ,伴有小脑幕急性硬膜下血肿 2例 ,颞顶部急性硬膜下血肿伴有大脑镰急性硬膜下血肿 2例 ,大脑镰、小脑幕急性硬膜下血肿伴有蛛网膜下腔出血 5例。 2 6例大脑镰与小脑幕急性硬膜下血肿均发生在单侧。大脑镰急性硬膜下血肿的形态有的在中线呈细线状 ,有的呈粗线状。血肿厚度 0 .3～ 1 .5cm不等。小脑幕急性硬膜下血肿表现为片状、新月形。结论　大脑镰、小脑幕和额颞底部急性硬膜下血肿是发生在少见部位的特殊类型急性硬膜下血肿 ,只要对此类血肿有所认识 ,CT检查不难确诊 ,但有时需要与蛛网膜下腔出血鉴别     

Enlarged cerebrospinal fluid spaces in infants with subdural hematomas

Computed tomography in 16 infants with subdural hematomas showed enlarged basal cisterns, a wide interhemispheric fissure, prominent cortical sulci, and varying degrees of ventricular enlargement. Radionuclide cisternography in eight of the 16 patients showed findings consistent with enlargement of the subarachnoid space rather than those of communicating hydrocephalus. Clinical findings and brief follow-up showed no convincing evidence for cerebral atrophy in 13 patients. These findings suggest that the enlarged subarachnoid space, which is encountered in some infants and may be a developmental variant, predisposes such infants to subdural hematomas.     

CT appearances of haematomas in the corpus callosum in patients with subarachnoid haemorrhage

Corpus callosum heamatoma is a rare feature in subarachnoid haemorrhage (SAH), which may result from aneurysms of the anterior communicating artery (ACoA) or pericallosal artery (PCA). In 348 patients with aneurysmal SAH, bleeding from ACoA aneurysms in 88 cases produced no abnormality on CT in 7. Blood in the cistern of the lamina terminalis was the most frequent abnormality (76/88); haematomas of the septum pellucidum, confined to patients with ACoA aneurysms, were seen in 26 (30%). Rupture of PCA aneurysms in 12 patients gave rise to blood in the pericallosal cistern, anterior interhemispheric fissure and cistern of the lamina terminalis in 11. There was no blood in the septum pellucidum or the ventricular system in any case, but haematomas in the corpus callosum occurred in 8 (67%). In all of these, blood extended into the anterodorsal aspect of the callosum and spread posteriorly along its dorsal border. An identical, supracallosal pattern was seen in 2 patients (2.5%) with ACoA aneurysms, in whom haemorrhage was more extensive, with a large frontal lobe haematoma extending up from the cistern of the lamina terminalis in 1 and a haematoma of the septum pellucidum, with intraventricular extension in the other. In 8 patients (9%) with ACoA aneurysms a corpus callosum haematoma appeared to result from passage of blood up through the cistern of the lamina terminalis into the septum pellucidum and thence into the ventral aspect of the anterior corpus callosum; blood was present within the cistern, the septum and the ventricles.     

CT诊断特殊征象的蛛网膜下腔出血

目的:探讨蛛网膜下腔出血的特殊CT征象,提高对此病变的诊断率。方法:回顾性分析17例经证实的具有特殊CT表现的蛛网膜下腔出血病例,分析其形成机理,CT表现特征及与硬膜下血肿的鉴别要点。结果:所有病例均含有颅骨内板下新月形高密度影这种酷似硬膜下血肿的CT表现,但具有内缘不锐利,密度较低且不均匀的特征。结论:CT可以诊断具此特殊表现的蛛网膜下腔出血并与硬膜下血肿鉴别。     

Posterior pericallosal lipoma extending through the interhemispheric fissure into the scalp via the anterior fontanelle

We report an unusual pericallosal lipoma presenting as scalp mass at birth. The patient had no obvious neurological deficit, but CT and MRI revealed a striking lipoma extending extracranially into the scalp from the interhemispheric fissure via the anterior fontanelle. The corpus callosum was distorted but not dysplastic.     

Fetal Pericallosal Lipoma: US and MR Findings

We report a case of fetal pericallosal lipoma occurring at the anterior interhemispheric fissure and associated with agenesis of the corpus callosum. During targeted prenatal ultrasonography at 26 weeks'' gestation, the lesion was seen as a highly echogenic mass. MR imaging performed at 35 weeks'' gestation and during the postnatal period revealed a pericallosal fatty mass and agenesis of the corpus callosum.     

Nontraumatic frontal lobe hemorrhages: Clinical-computed tomographic correlations

Summary Correlation of lesion location and appearance with clinical sequelae in 25 patients with CT-proven frontal lobe hematomas reveals 10 of 25 hematomas were located above the frontal horns of the lateral ventricles. Nine of the 10 patients were normotensive. All presented with contralateral motor and sensory deficits. Four of 25 hematomas were situated inferior to the frontal horns. All these patients were hypertensive, rapidly became comatose and exhibited hemiplegia, hemianesthesia and gaze preference contralateral to the hemiplegia. Five patients had frontal hematomas which extended inward from the interhemispheric fissure or caval-septal region. All were normotensive. All had anterior cerebral-anterior communicating artery aneurysms on angiography. Four patients had hematomas involving both the frontal and temporal region. All were normotensive with no known cause for hemorrhage. Two patients had bifrontal hematomas; one had butterfly appearance extending across the interhemispheric fissure and the other was midline but had no interhemispheric blood. Both were normotensive. One had an anterior cerebral-anterior communicating artery aneurysm.     

Interhemispheric fissure sign of dysgenesis of the corpus callosum

Failure to develop of the corpus callosum and the neighboring midline structures results in abnormal proximity between the interhemispheric fissure (IHF) and the third ventricle. We have called this finding the IHF sign of dysgenesis of the corpus callosum (DCC). In a retrospective study of 39 cases the presence of the IHF sign was assessed in conjunction with the other well recognized CT manifestations of the disorder. These are: (a) lateral ventricles: pointing of the frontal horns, disproportionate enlargement of the occipital horns and separation of bodies of the lateral ventricles; (b) third ventricle: enlargement, elevation and anterior displacement; and (c) interventricular foramen: enlargement. We found that the IHF sign was present concurrently with the other CT signs of DCC in all 35 cases (100%) where the quality of the CT scans permitted its satisfactory evaluation; in the remaining four the sign could not be assessed because of the unsatisfactory quality of the CT scans. Our study confirms that the IHF sign is an additional reliable CT feature of DCC.     

急性大脑镰和小脑幕硬膜下血肿的CT及磁共振成像诊断

目的探讨急性大脑镰和小脑幕硬膜下血肿的CT及磁共振成像特征。方法回顾性分析17例急性大脑镰和小脑幕硬膜下血肿的CT及磁共振成像表现。结果 17例急性大脑镰和小脑幕硬膜下血肿中,大脑镰硬膜下血肿5例,小脑幕硬膜下血肿7例,大脑镰并小脑幕硬膜下血肿5例,6例伴有颅盖骨(大脑凸面)部位的硬膜下血肿或脑实质挫裂伤。结论急性大脑镰和小脑幕硬膜下血肿较少见,易误诊为蛛网膜下腔出血、大脑镰钙化,CT和磁共振成像征象具特征性,有助于鉴别。     

特殊部位硬膜下血肿的CT诊断

目的 探讨大脑镰,小脑幕硬膜下血肿的CT特点。资料与方法 回顾性分析32例大脑镰,小脑幕硬膜下血肿的CT和临床资料。结果 32例中大脑镰硬膜下血肿20例,CT表现为内缘平直,外缘弧形或波浪形的带状高密度影;小脑幕硬膜下血肿12例,CT表现为高密度片状影3例,新月状影3例,U形影2例,累及大脑镰后部4例,呈Y形或镰刀状。结论 大脑镰,小脑幕硬膜下血肿的CT表现具有特征性,CT复查对其诊断和鉴别诊断很有意义。     

大脑镰硬膜下血肿的CT诊断

目的评价CT对大脑镰硬膜下血肿诊断的可行性。方法回顾性分析25例具有完整资料的外伤性大脑镰硬膜下血肿的CT表现。结果25例中,14例表现细绳索状高密度影,11例表现粗绳索状高密度影;粗绳索状影近中线侧平直,外侧呈浅波浪状,其对应脑回受压远离中线,脑沟及纵裂池模糊或消失。结论大脑镰硬膜下血肿是硬膜下血肿的一种少见类型,通过分析CT征象,能够作出正确诊断。     

Holoprosencephaly: an analysis of callosal formation and its relation to development of the interhemispheric fissure.

PURPOSETo correlate the degree of hemispheric fusion in holoprosencephaly with degree of callosal formation, with degree of thalamic and basal ganglia fusion, and with presence or absence of dorsal cyst.METHODSMR, CT, and ultrasonography from 19 patients with holoprosencephaly was retrospectively reviewed. The imaging studies were graded according to extent of the hemispheric fusion, thalamic fusion, corpus striatum fusion, callosal formation, and the presence or absence of a dorsal cyst. These factors were statistically correlated with each other using Kendall rank correlation coefficient.RESULTSThere were significant correlations between hemispheric fusion and failure of corpus callosum formation, presence of dorsal cyst and failure of corpus callosum formation, and hemispheric fusion and presence of dorsal cyst. Additional correlations were noted between thalamic fusion and corpus striatum fusion.CONCLUSIONSOur results suggest that the presence of an interhemispheric fissure is necessary for callosal formation, and the presence of a dorsal cyst may interfere with callosal formation in holoprosencephaly.     

Frontal subcutaneous lipoma associated with large interhemispheric lipoma and corpus callosum agenesis

Intracranial lipomas are extremely rare fat-containing lesions that comprise 0.1%-0.5% of all primary brain tumors. They are congenital lesions that arise due to persistence and maldifferentiation of the meninx primitive (subarachnoid space precursor). We report a case of a 30-year-old woman who presented with seizures due to an intracranial lipoma and no neurological deficits. CT (computerized tomography) imaging findings demonstrated a large interhemispheric partially calcified lipoma that communicated with a large scalp lipoma and was associated with agenesis of the corpus callosum. Compared to the prior CT imaging, the lipoma increased in size from 3.4 cm to 4.1 cm transversely. A recent CT angiogram done due to suspicion of an aneurysm showed the lipoma now measuring 6 cm by 4.7 cm. Most cases of intracranial lipoma have been reported in the pediatric age group. Here, we report a rare case of interhemispheric intracranial lipoma in the adult age group. This case also demonstrates the importance of imaging modalities for detecting intracranial lipoma without performing invasive brain biopsy.     

Growth-mechanism of giant intracranial aneurysms; demonstration by CT and MR imaging

Summary In four cases of giant intracranial aneurysm, CT demonstrated a hyperdense open-, or closed-ring structure at the periphery of the aneurysm. Surgery in two of the cases demonstrated that this peripheral hyperdensity represents fresh clot inside the wall of the thrombosed mass. An analogy is established between giant intracranial aneurysms, chronic subdural hematomas and growing encapsulated intracerebral hematomas. The common feature of the three entities is slow growth by recurrent hemorrhages into the lesion. It is proven that growth of chronic subdural hematomas and of growing encapsulated hematomas is related to recurrent hemorrhage from capillaries sprouting within the membrane of the lesion. The highly vascularized membranous wall of a giant intracranial aneurysm seems to behave like the membrane of a chronic subdural hematoma. It is suggested that the giant intracranial aneurysm grows by recurrent hemorrhage into its wall and behaves like growing encapsulated hematomas.     

Diagnosis of extracerebral fluid collections by computed tomography.

The computed tomography scans of 90 patients with extracerebral fluid collections were reviewed. Epidural hematomas, acute, subacute, and chronic subdural hematomas, convexity subarachnoid hemorrhages, subdural hygromas, and one epidural empyema were seen. The CT findings were analyzed and correlated with the time elapsed since injury (when known) and the results of radionuclide scans (when available). The overall accuracy of CT in detecting extracerebral fluid was 90% with no acute hemorrhages missed. In subacute and chronic subdural collections, six CT scans were false negative in whole or in part. Three false positive interpretations were made and are discussed.     

蛛网膜下腔出血的CT诊断及其漏误诊原因分析

目的探讨蛛网膜下腔出血的CT诊断并分析其误诊、漏诊的常见原因。方法对100例经CT复查证实的蛛网膜下腔出血CT资料进行回顾性分析。结果100例中因出血部位及出血量不同,CT表现为分布于脑沟、裂、池内的线状、带状、片状或铸型高密度影。纵裂池及小脑幕出血灶边缘一般较模糊。出血部位以侧裂池和脚间窝最多,分别为46例及56例,2例纵裂池出血首次误诊为硬膜下血肿;1例四叠体池出血因出血量少首次CT检查为阴性,通过适时CT复查得以确诊。结论CT对蛛网膜下腔出血的诊断价值较高,可避免漏诊及误诊,并对其临床治疗具有重要把寻意义。     

Subdural hematomas in infants with benign enlargement of the subarachnoid spaces are not pathognomonic for child abuse

BACKGROUND AND PURPOSE: Patients who have benign enlargement of the subarachnoid spaces (BESS) have long been suspected of having an increased propensity for subdural hematomas either spontaneously or as a result of accidental injury. Subdural hematomas in infants are often equated with nonaccidental trauma (NAT). A better understanding of the clinical and imaging characteristics of subdural hematomas that occur either spontaneously or as a result of accidental trauma may help distinguish this group of patients from those who suffer subdural hematomas as a result of NAT. The purpose of this study is to describe the clinical and imaging characteristics of subdural hematomas that occur either spontaneously or as a result of accidental injury in infants with BESS. METHODS: We conducted a retrospective review of all patients with BESS complicated by subdural hematomas evaluated at a single institution from 1998 to 2004. Data concerning the patient's clinical presentation, physical findings, imaging, and management are described. RESULTS: During the study period, 7 patients with BESS complicated by subdural hematoma were identified. Their mean age at identification of the subdural hematoma was 7.4 months of age. In 5 cases, there was no recognized trauma before identification of the subdural hematoma. In 3 cases, baseline CT or MR imaging was available, showing prominent subarachnoid spaces without any evidence of subdural hemorrhage. CONCLUSION: Although suspicious for NAT, subdural hematomas can occur in children either spontaneously or as a result of accidental trauma. Caution must be exercised when investigating for NAT based on the sole presence of subdural hematomas, especially in children who are otherwise well and who have BESS.     

Loss of interhemispheric connectivity in patients with lacunar infarction reflected by diffusion-weighted MR imaging and single-photon emission CT.

BACKGROUND AND PURPOSE: Although decreased neuronal connectivity in white matter has been reported to be a key mechanism of vascular dementia, assessment of white matter changes by diffusion-weighted MR imaging in relation to measures of associative function has not been previously addressed. We evaluated the loss of interhemispheric neuronal connectivity in vascular dementia by measuring diffusional anisotropy of the corpus callosum and determining its relationship to the regional cortical activity as reflected by cortical perfusion. METHODS: Nine patients with multiple lacunar infarction and six healthy volunteers (25-35 years old) were examined. We developed a method to determine the active cortical volume (ACV) by masking iodine-123 iodoamphetamine SPECT scans to eliminate the effect of brain atrophy. The anisotropic rate (AR) was calculated as a ratio of two perpendicular diffusion coefficients in diffusion-weighted MR imaging. RESULTS: Compared with the ACVs of the healthy volunteers, there were significant decreases in the ACVs in the frontal associative areas in the patients, and these were significantly correlated with cognitive scores. The frontal ACVs showed good correlations with the AR of the anterior corpus callosum among all participants; however, only insignificant trends toward correlation were observed between these two parameters within the patient group. CONCLUSION: A possible relationship between diffusional anisotropy of the anterior corpus callosum and frontal associative function was suggested; however, an estimation of the decrease in neuronal connectivity in patients with multiple lacunar infarction in terms of the deterioration in diffusional anisotropy requires further documentation.     

False positive appearance of subarachnoid hemorrhage on CT with bilateral subdural hematomas

We describe a patient with bilateral traumatic subdural hematomas in whom CT findings of hyperattenuation in the basal cisterns and subarachnoid spaces falsely suggested superimposed acute subarachnoid hemorrhage.