OBJECTIVE: The secondary verification of Leksell Gamma Knife treatment planning system (LGP) (which is the primary verification system) is extremely important in order to minimize the risk of treatment errors. Although prior methods have been developed to verify maximum dose and treatment time, none have studied maximum dose coordinates and treatment volume. METHODS: We simulated the skull shape as an ellipsoid with its center at the junction between the mammillary bodies and the brain stem. The radiation depths of the beamlets emitted from 201 collimators were calculated based on the relationship between this ellipsoid and a single beamlet expressed as a straight line. A computer program was coded to execute the algorithm. A database system was adopted to log the doses for 31x31x31 or 29,791 matrix points allowing for future queries to be made of the matrix of interest. RESULTS: When we compared the parameters in seven patients, all parameters showed good correlation. The number of matrix points with a dose higher than 30% of the maximal dose was within +/- 2% of LGP. The 50% dose volume, which is generally the target volume, differs maximally by 4.2%. The difference of the maximal dose ranges from 0.7% to 7%. CONCLUSION: Based on the results, the variable ellipsoid modeling technique or variable ellipsoid modeling technique (VEMT) can be a useful and independent tool to verify the important parameters of LGP and make up for LGP.
Brain Stem ; Enzyme Multiplied Immunoassay Technique ; Humans ; Mamillary Bodies ; Radiosurgery ; Skull ; Software

Gelastic Seizure(Ictal laughter) is frequently associated with hypothalamic hamartoma that is congenital tumor composed of heterotrophic and hyperplastic tissue located in the hypothalamus near the interpeduncular cistern, tuber cinereum, and mamillary body. The seizure usually begins in infancy or childhood and may be accompanied with precocious puberty and cognitive decline. A 14 year-old boy visited to our hospital because of paroxysmal frequent involuntary laughing regardless of emotional change. Brain MRI showed nonenhancing hypothalamic mass that had isointensity with gray matter on T1W1 and hyperintensity on T2Wl. So it was suspected that he had a gelastic seizure accompanied with hypothalamic hamartoma.
Adolescent ; Brain ; Hamartoma* ; Humans ; Hypothalamus ; Magnetic Resonance Imaging ; Male ; Mamillary Bodies ; Puberty, Precocious ; Seizures* ; Tuber Cinereum

This study presents seven patients with hypothalamic hamartomas diagnosed on the basis of MRI. Histological confirmation was performed in one patient who underwent surgery. Four patients presented with epilepsy, including gelastic seizures. Other symptoms were behavior abnormalities in 3 patients and precocious puberty in 4 patients. We classify hypothalamic hamartomas into four subgroups according to MRI finding: Types la lesions were less than 100mm in lesions less than 10mm and mammillary body. Type lla lesions were more than 100mm in diamenter and sessilely attached to hypothalamus with slight hypothalmic displacement and Type llb lesions more than 10mm and with marked displacement of hypothalamus. We could achieve good result with surgical resection in one patient with Type llb hamartoma associated with gelastic seizure that was unresponsive to medical treatment. We performed gamma knife radiosurgery in three patients with gelastic seizue(2 patients with Type lla and 1 patient with Type llb) and three patients with precocious puberty(2 patients with Type la and 1 patient with Type lla 1 patient with Type llb) and three patients with precocious puberty(2 patients with Type la and 1 patient with type lb). The authors propose direct surgery as a treatment for this progressive syndrome and gamma knife radiourgery is alternative treatment for high risk patients.
Epilepsy ; Hamartoma* ; Humans ; Hypothalamus ; Magnetic Resonance Imaging ; Mamillary Bodies ; Puberty, Precocious ; Radiosurgery ; Seizures

Wernicke's encephalopathy (WE) is an acute neuropsychiatric syndrome resulting from thiamine deficiency. Traditionally, diagnosis of WE rests on a clinical symptom triad consisting of ocular signs, altered consciousness, and ataxia. However, the complete triad is only present in a fraction of cases, which means that WE tends to be under-diagnosed, especially in nonalcoholic patients. Brain MRI of WE patients usually shows symmetrical signal intensity alterations in the thalami, mammillary bodies, and periaqueductal area, because of cytotoxic edema in the same region. These typical findings are useful diagnostic leads in WE patients with atypical symptoms. However, atypical findings can occasionally be seen in the vermis of cerebellum and cerebellar nuclei. Notably, alterations of signal intensity in the cerebellar dentate nuclei, which is a typical finding of metronidazole-induced encephalopathy (MIE), need to be distinguished according to medication history and response to thiamine.
Ataxia ; Brain ; Cerebellar Nuclei ; Cerebellum ; Consciousness ; Edema ; Humans ; Mamillary Bodies ; Metronidazole ; Thiamine ; Thiamine Deficiency ; Wernicke Encephalopathy

Adult onset Leigh syndrome is a very rare neurodegenerative disorder of unknown cause. We report the evolution of the lesions on serial MRIs in a 38-year-old man with clinically diagnosed Leigh syndrome. We emphasize that the mammillary bodies can be involved during the disease course and that premortem diagnosis of Leigh syndrome is pos-sible, if a characteristic distribution of lesions can be demonstrated on MRI.
Adult* ; Diagnosis ; Humans ; Leigh Disease* ; Magnetic Resonance Imaging* ; Mamillary Bodies ; Neurodegenerative Diseases

It is controversial whether isolated lesions of mammillothalamic tract (MTT) produce significant amnesia. Since the MTT is small and adjacent to several important structures for memory, amnesia associated with isolated MTT infarction has been rarely reported. We report a patient who developed amnesia following an infarction of the left MTT that spared adjacent memory-related structures including the anterior thalamic nucleus. The patient s memory deficit was characterized by a severe anterograde encoding deficit and retrograde amnesia with a temporal gradient. In contrast, he did not show either frontal executive dysfunction or personality change that is frequently recognized in the anterior or medial thalamic lesion. We postulate that an amnesic syndrome can develop following discrete lesions of the MTT.
Aged ; Amnesia/*etiology ; Cerebral Infarction/*complications ; Humans ; Male ; Mamillary Bodies/*physiopathology ; Neuropsychological Tests ; Thalamus/*physiopathology

Neuroglial cells are actively participate in the pathogenesis or in the recovery procedures following brain lesions. The study was performed to evaluate the plasticity of glial cells following different degree of brain lesions. Neurosurgical operations were made on the rats fixed on the stereotaxic apparatus. Tissue column of 3 mm-diameter was isolated in the caudatoputamen with concomitant severe bleeding in the first group. In the second group, the sensorimotor cortex was suctioned out with moderate bleeding. In the third group, the mammillary body was electrically coagulated with minimal bleeding. Caudatoputamens, as a lesioned tissue or as a target tissue of lesioned area, were studied light and electron microscopically. Observations on reactivities and plasticities of neuroglial cells on the different situations, the following results were obtained : 1. Astrocytes were swollen within an hour following brain lesions. 2. In case of smaller lesion, astroglia alone remove altered structures. 3. Microglia are increased in number, if the lesion is large with severe bleeding. The microglia might come from blood monocyte via transformation to pericyte. 4. In large lesion, astroglia were greatly hypertropied, and microglia might be moving and functioning effeciently within the hypertropied cytoplasm of astroglia. 5. In the stabilizing stage, astroglia produce glial fibers and fix the exhausted microglia. Fixed microglia are proceed into apoptotic process in the cytoplasm of astroglia and removed by them. All these procedures might be controlled by various receptors and secretions of astroglia. It means that astroglia is not only the basic supporting element of nervous tissue, but also an actively functioning element for the most effective homeostatic functioning of the neuropil.
Animals ; Apoptosis ; Astrocytes ; Brain* ; Cytoplasm ; Hemorrhage ; Mamillary Bodies ; Microglia ; Monocytes ; Neuroglia* ; Neuropil ; Pericytes ; Plastics* ; Rats ; Suction

A 41-year-old man was admitted due to altered mentality and confusion. He had showed progressive cerebellar ataxia, dysarthria, gait disturbance from his age of 33 years old. Brain MRI revealed high signal lesions in periaqueductal gray matter, mammillary bodies, median thalami and postcentral gyri bilaterally on T2-weighted images. Severe cerebellar atrophy was noted, too. We report a case of Wernicke's encephalopathy in a patient with probable multiple system atrophy. As far as we know, there have been no published report on this kind of case.
Adult ; Atrophy ; Brain ; Cerebellar Ataxia ; Dysarthria ; Gait ; Humans ; Magnetic Resonance Imaging ; Mamillary Bodies ; Multiple System Atrophy* ; Periaqueductal Gray ; Wernicke Encephalopathy*

PURPOSE: To evaluate the MR imaging findings of patients with mesial temporal sclerosis. MATERIALS AND METHODS:We retrospectively reviewed the MR imaging findings of 116 patients diagnosed by MRI as suffering from mesial temporal sclerosis. In 18 of these, the condition was also histologically proven. RESULTS: Among the 116 patients, volume loss of the hippocampus was found in 95 (81.9%) and signal changes of the hippocampus in 53 (45.7%). Decreased signal intensity in the hippocampus on T1-weighted images was found in 13 (11.2%) and increased signal on T2-weighted images in 50 (43.1%). Signal abnormality in the hip-pocampus on both T1- and T2-weighted images was found in ten, and associated extrahippocampal abnormali-ties, as follows, in 20 (17.2%): atrophy of the fornix (n=10), atrophy of the mammillary body (n=8), atrophy of the amygdala (n=10), atrophy or increased T2 signal intensity of the anterior thalamic nuclei (n=2), atrophy of the cingulate gyrus (n=2), atrophy or increased signal intensity of the anterior temporal lobe (n=8), and cere-bral hemiatrophy (n=4). CONCLUSION: A high T2 signal and atrophy of the hippocampus are the most common and important MRI findings of mesial temporal sclorosis. Other abnormal findings, if any, which may be found in extrahippocampal structures such as the fornix, mammillary body and temporal lobe, should, however, also be carefully observed
Amygdala ; Anterior Thalamic Nuclei ; Atrophy ; Epilepsy ; Gyrus Cinguli ; Hippocampus ; Humans ; Magnetic Resonance Imaging* ; Mamillary Bodies ; Retrospective Studies ; Sclerosis* ; Temporal Lobe

A 25 year old female patient with hyperemesis gravidarum developed mental confusion, gait disturbance and diplopia. MRI of this patient showed high-signal lesions in thalamus, floor of the fourth ventricle, periaqueductal gray matter, mammillary body, and corpora quadrigemina, The high signal areas correlated well with the anatomical distribution of pathologic lesions in wernicke's encephalopathy previously described.
Adult ; Diplopia ; Female ; Fourth Ventricle ; Gait ; Humans ; Hyperemesis Gravidarum* ; Magnetic Resonance Imaging* ; Mamillary Bodies ; Periaqueductal Gray ; Pregnancy ; Tectum Mesencephali ; Thalamus ; Wernicke Encephalopathy*