An encepholocele is defined as a herniation of cranial contents through a defect in the skull. Encephaloceles are classified accroding to their contents and location. Encephalocele is a useful general term to refer to common features of the various forms of anomaly, but considerable differences exist in the pathology, treatment and prognosis of encephaloceles at each anatomical location. Improved neuroimaging facilities, especially MRI, make it easy not only to detect the encephalocele including its contents and location, but also to get preoperative informations. We have reviewed a total of 22 patients with encephalocele whom we have experienced from 1986, July to 1990, June. Twelve were at occipital location, six at cranial vault, three at cranial base, one at frontoethmoidal location. The size of cranium bifidum and herniating sac of the cranial vault and occipital location is larger than that of frontobasal location. The incidence of associated hydrocephalus is in order of occipital, cranial vault, frontobasal form, and its prognosis is also better in frontobasal form than in occipital of cranial vault form.
Encephalocele* ; Humans ; Hydrocephalus ; Incidence ; Magnetic Resonance Imaging ; Neuroimaging ; Pathology ; Prognosis ; Skull ; Skull Base

OBJECTIVE: The authors developed a stereotactic device for irradiation of small animals with Leksell Gamma Knife(R) Model C. Development and verification procedures were described in this article. METHODS: The device was designed to satisfy three requirements. The mechanical accuracy in positioning was to be managed within 0.5 mm. The strength of the device and structure were to be compromised to provide enough strength to hold a small animal during irradiation and to interfere the gamma ray beam as little as possible. The device was to be used in combination with the Leksell G-frame(R) and KOPF(R) rat adaptor. The irradiation point was determined by separate imaging sequences such as plain X-ray images. RESULTS: The absolute dose rate with the device in a Leksell Gamma Knife was 3.7% less than the value calculated from Leksell Gamma Plan(R). The dose distributions measured with GAFCHROMIC(R) MD-55 film corresponded to those of Leksell Gamma Plan(R) within acceptable range. The device was used in a series of rat experiments with a 4 mm helmet of Leksell Gamma Knife. CONCLUSION: A stereotactic device for irradiation of small animals with Leksell Gamma Knife Model C has been developed so that it fulfilled above requirements. Absorbed dose and dose distribution at the center of a Gamma Knife helmet are in acceptable ranges. The device provides enough accuracy for stereotactic irradiation with acceptable practicality.
Animals ; Gamma Rays ; Head Protective Devices ; Rats

We analyzed 91 cases with seizures after stroke(except subarachnoid hemorrhage) to see, recurrence rate, onset time, lesion sites and electroencephalographic findings. Overall incidence of seizure was 5.73%[7.57% of all cerebral infarction(CI; 938 cases) and 3.0% of an intracerebral hemorrhage(ICH; 649 cases)] in all admitted stroke patient(l450) from Jan. 1980 to Jun. 1989 and all stroke patients visited out-patient department(137 ; from Sep. 1989 to Oct. 1989) in the department of neurology, Seoul National University Hosptal. And then, we excluded 22 cases because of insufficient clinical information.1) We followed up 69 patients and in those cases, seizures occurred rnore frequently in CI(51) than in ICH(18). 2) Seizures of ear!y onset(<2week) occurred in 25(49.0%) of 51 cases with cerebral infarction and in 12(66.7%) of 18 cases with IVH. 3) Seizures occurred more frequently in cortical lesions(71.0%)[CI: 71.4% and ICH ; 28.6%] than in subcortical lesions(24.6%)[CI ; 76.5% and ICH ; 23.5%]. 4) Recurrence rate (69.5%) of the patients without antiepileptic medication was signigicantly higher than (16.7%) of patients with medication[Spearman's Rho=0.52, p<0.001]. 5) Of those patients without medication, the recurrence rate was highest in the patients showing epileptiform discharge(100%) in EEG. Followed by focal slowing(66.7%), diffuse slowing(62.5%) and normal EEG features(33.3%)[Spearman's Rho=0.41, P=0.01]. 6) The recurrence of seizures was more frequent in the patients with CI(54.9%) than in ICH(22.2%).
Cerebral Infarction ; Electroencephalography ; Humans ; Incidence ; Neurology ; Outpatients ; Recurrence ; Seizures* ; Seoul ; Stroke

INTRODUCTION: It has been reported that the survival of low-grade glioma patients depends upon the time of malignant transformation. The authors presents the clinical analysis of histologically proven trasformed gliomas. MATERIALS AND METHODS: A total 92 patients who were consecutively treated and histologically confirmed hemispheric low-grade gliomas between 1980 and 1998 were analyzed and followed. All cases meet the criteria of WHO glioma classification of grade II. RESULTS: The mean follow-up period was 73 months. Twenty two among 92 cases(24%) were histologically proven to be transformed into malignant ones. The mean time to transformation was 56 months. The 5-year and 10-year survival rates of the transformed group were 66% and 30% respectively and significantly different from the survival rates of the non-transformed group(p=0.0018). Among clinical factors at presentation, the initial tumor volume had a tendency to be larger in the transformed group than that of the non-transformed group and became significant when it was divided into more than 30cm3 or not(p=0.02). Among therapeutic factors, the extent of removal had no influence on the rate of malignant transformation. But postoperative radiation therapy were more frequently given to the pre-transformed group than the non-transformed group and the frequency was significantly different(p=0.02). CONCLUSIONS: The authors had found that the initial tumor volume and radiation therapy could be clinical prognostic factors for the malignant transformation of low-grade gliomas.
Classification ; Follow-Up Studies ; Glioma* ; Humans ; Survival Rate ; Tumor Burden

PURPOSE: The purpose of this study was to evaluate the associated brain parenchymal abnormalities of developmental venous anomalies (DVA) with susceptibility-weighted image (SWI). MATERIALS AND METHODS: Between January 2012 and June 2013, 2356 patients underwent brain MR examinations with contrast enhancement. We retrospectively reviewed their MR examinations and data were collected as per the following criteria: incidence, locations, and associated parenchymal signal abnormalities of DVAs on T2-weighted image, fluid-attenuated inversion recovery (FLAIR), and SWI. Contrast enhanced T1-weighted image was used to diagnose DVA. RESULTS: Of the 2356 patients examined, 57 DVAs were detected in 57 patients (2.4%); 47 (82.4%) were in either lobe of the supratentorial brain, 9 (15.7%) were in the cerebellum, and 1 (1.7%) was in the pons. Of the 57 DVAs identified, 20 (35.1%) had associated parenchymal abnormalities in the drainage area. Among the 20 DVAs which had associated parenchymal abnormalities, 13 showed hemorrhagic foci on SWI, and 7 demonstrated only increased parenchymal signal abnormalities on T2-weighted and FLAIR images. In 5 of the 13 patients (38.5%) who had hemorrhagic foci, the hemorrhagic lesions were demonstrated only on SWI. CONCLUSION: The overall incidence of DVAs was 2.4%. Parenchymal abnormalities were associated with DVAs in 35.1% of the cases. On SWI, hemorrhage was detected in 22.8% of DVAs. Thus, we conclude that SWI might give a potential for understanding of the pathophysiology of parenchymal abnormalities in DVAs.
Brain* ; Cerebellum ; Drainage ; Hemorrhage ; Humans ; Incidence ; Magnetic Resonance Imaging* ; Pons ; Retrospective Studies

PURPOSE: We wanted to compare the fMRIs (functional magnetic resonance images) obtained during a lexical decision task and also during a word generation task, and we wanted to evaluate the usefulness of using a lexical decision task for the visualization of the brain language area and for the determination of language dominance. MATERIALS AND METHODS: Sixteen patients (9 women and 7 men) who had had undergone the Wada test were included in our study. All the patients were left dominant for language, as tested for on the Wada test. The functional maps of the brain language area were obtained in all the subjects during the performance of a lexical decision task and also during the performance of a word generation task. The MR examinations were performed with a 1.5 T scanner and with using the EPI BOLD technique. We used the SPM program for the postprocessing of the images. The threshold for significance was set at p<0.001 or p<0.01. A lateralization index was calculated from the number of activated pixels in each hemispheric region (the whole hemisphere, the frontal lobe and the temporoparietal lobe), and the hemispheric language dominance was assessed by the lateralization index; the results were then compared with those results of the Wada tests. The differences for the lateralization of the language area were analyzed with regard to the stimulation tasks and the regions used for the calculation of the lateralization indices. RESULTS: The number of activated pixels during the lexical decision task was significantly smaller than that of the word generation task. The language dominance based on the activated signals in each hemisphere, was consistent with the results of the Wada test for the word generation tasks in all the subjects. On the lexical decision task, the language dominance, as determined by the activated signals in each hemisphere and the temporoparietal lobe, correlated for 94% of the patients. The mean values of the lateralization index for the lexical decision task were higher than those mean values of the lateralization index of the word generation task. CONCLUSION: The lexical decision task allowed us to map the language area and to determine the language dominance. It could be a useful task for those patients who cannot perform the word generation task because of their cognitive retardation.
Brain ; Female ; Frontal Lobe ; Humans ; Magnetic Resonance Imaging*

OBJECTIVE: In order to investigate the functional brain anatomy associated with verbal and visual working memory, functional magnetic resonance imaging was performed. MATERIALS AND METHODS: In ten normal right handed subjects, functional MR images were obtained using a 1.5-T MR scanner and the EPI BOLD technique. An item recognition task was used for stimulation, and during the activation period of the verbal working memory task, consonant letters were used. During the activation period of the visual working memory task, symbols or diagrams were employed instead of letters. For the post-processing of images, the SPM program was used, with the threshold of significance set at p < .001. We assessed activated brain areas during the two stimulation tasks and compared the activated regions between the two tasks. RESULTS: The prefrontal cortex and secondary visual cortex were activated bilaterally by both verbal and visual working memory tasks, and the patterns of activated signals were similar in both tasks. The superior parietal cortex was also activated by both tasks, with lateralization to the left in the verbal task, and bilaterally without lateralization in the visual task. The inferior frontal cortex, inferior parietal cortex and temporal gyrus were activated exclusively by the verbal working memory task, predominantly in the left hemisphere. CONCLUSION: The prefrontal cortex is activated by two stimulation tasks, and this is related to the function of the central executive. The language areas activated by the verbal working memory task may be a function of the phonological loop. Bilateral prefrontal and superior parietal cortices activated by the visual working memory task may be related to the visual maintenance of objects, representing visual working memory.
Adult ; Brain/*anatomy & histology/physiology ; Echo-Planar Imaging ; Female ; Human ; *Magnetic Resonance Imaging ; Male ; Memory/*physiology ; Photic Stimulation ; Support, Non-U.S. Gov't

PURPOSE: To compare the detection rate of unenhanced CT, spin-echo T2-weighted, fast fluid-attenuatedin-version- recovery(FLAIR), and diffusion-weighted MR imaging in the diagnosis of hyperacute middle cerebralartery(MCA) territory infarction. MATERIALS AND METHODS: Sixteen patients with clinically proven hyperacute MCAterritory infarction were e-valuated with unenhanced CT and MR. All CT examinations were performed within sixhours of the onset of symptoms and all MR studies were performed within two hours of CT. All images were evaluatedindepen-dently by two radiologists in possession of brief clinical information. Positive imaging criteria wereparenchy-mal hypoattenuation, as seen on CT, and increased signal intensity, as seen on MR. For quantitativeanalysis, we measured the attenuation and signal intensity of the lesion and contralateral normal parenchyma, andper-centage contrast-to-noise ratios(CNRs) of the lesions were also calculated. RESULTS: Positive findings weredetected in all patients on diffusion-weighted images, in 13(81%) on CT, in 10 ( 63 %) on fast FLAIR images, andin 7(44 %) on T2-weighted images. Lesion percentage CNRs were 30% for diffusion-weighted imaging, 15 % for CT, 18% for FLAIR MR imaging, and 16 % for T2-weighted MR imag-ing(p < .004 for diffusion-weighted imaging vs others). CONCLUSION: For hyperacute MCA territory infarction, diffusion-weighted MR imaging was the most sensitive imagingtechnique and unenhanced CT was superior to fast FLAIR or T2-weighted imaging.
Diagnosis ; Humans ; Infarction* ; Magnetic Resonance Imaging* ; Middle Cerebral Artery*

The medical records of 30 patients with histologically confirmed and angiographically occult intracranial vascular malformations(AOVM), who underwent surgery between May 1988 and May 1993, were reviewed retrospectively to determine whether their radiological and clinical characteristics are helpful in differential diagnosis. Histological diagnoses were cavernous angioma(CA) in 17 cases, arteriovenous malformation(AVM) in nine, venous angioma in one and unclassified vascular malformation in three. The most common initial presenting mode was intracranial hemorrhage(ICH ; 18 cases, 60.0%), followed by seizure(11 cases, 33.3%) and headache(two cases, 6.6%). CA, once it had bled, tended to bleed repeatedly, and this occurred before surgery in seven of nine cases of CA presenting with ICH. On CT scan, calcification was observed only in CA(two cases). On MRI images obtained in 28 patients, a mottled density mass with or without adjacent ICH(ten of 16 CA's) and multiple lesions(three of 16 CA's) were pathognomonic for CA, while single stage ICH(two of eight AVM's) and signal void(three of eight AVM's) were observed only in cases of AVM. Findings of MRI such as multiple stage hemorrhage, low signal intensity rim or edema around the lesion were not helpful in differential diagnosis of the histological type of lesions. After enhancement with gadolinium, one case of AVM and another of venous angioma showed a serpentine pattern of enhancement. In 29 cases, the results of surgery were excellent ; there was no mortality and morbidity in only one case. In conclusion, CA, once it had bled, tended to rebleed and MRI was helpful in the differential diagnosis of AOVM's. MRI findings such as a mottled density mass or multiple lesions were pathognomonic for CA, while single stage hemorrhage or signal void were findings of AVM.
Arteriovenous Malformations ; Diagnosis ; Diagnosis, Differential ; Edema ; Gadolinium ; Hemangioma ; Hemangioma, Cavernous ; Hemorrhage ; Humans ; Magnetic Resonance Imaging ; Medical Records ; Mortality ; Retrospective Studies ; Tomography, X-Ray Computed ; Vascular Malformations*

In order to analyze and evaluate the role of surgical treatment and clinical outcome in patients with intracranial cavernous angiomas, we retrospectively reviewed the medical records of 30 patients who underwent surgery between 1988 and 1995. Preoperative symptoms and signs were intracranial hemorrhage(ICH) in 16 cases(53%), seizure in 14(47%) and neurologic deterioration due to effect of the mass in seven(23%). Four of the 16 patients admitted because of ICH had a previous history of this condition. Intervals between hemorrhages varied from 5 days to 20 months, with a mean of 7.4 months. The mass was removed gross-totally in 27 patients, subtotally in two and partially in one; post-operative neurologic status was aggravated in only two patients. Lesions had recurred in five of the 27 patients from whom these were thought to have been totally removed; in one case, there was recurrent hemorrhage sixteen months after surgery. Four of the five recurrent cases had been operated on immediately after ICH, and in the other a lesion which contained calcification had been seen. Only one of the 12 patients who had shown preoperative seizures and was followed up for at least 12 months after surgery continued to suffer from seizures after removal of the lesion. In conclusion, our study demonstrated that after initial bleeding, hemorrhaging tends to recur in thses lesions, and that if they are removed immediately after ICH, there is a risk that the angioma may recur.
Hemangioma ; Hemangioma, Cavernous* ; Hemorrhage ; Humans ; Intracranial Hemorrhages ; Medical Records ; Recurrence ; Retrospective Studies ; Seizures