PURPOSE: We designed the aft-multiple-slit (AMS) system to reduce scatter in cone-beam computed tomography (CBCT). As a preliminary study, we performed a Monte Carlo N-Particle Transport Code (MCNP) simulation to verify the effectiveness of this system. MATERIALS AND METHODS: The MCNPX code was used to build the AMS geometry. An AMS is an equi-angled arc to consider beam divergence. The scatter-reduced projection images were compared with the primary images only and the primary plus scatter radiation images with and without AMS to evaluate the effectiveness of scatter reduction. To obtain the full 2 dimensional (2D) projection image, the whole AMS system was moved to obtain closed septa of the AMS after the first image acquisition. RESULTS: The primary radiation with and without AMS is identical to all the slit widths, but the profiles of the primary plus scattered radiation varied according to the slit widths in the 2D projection image. The average scatter reduction factors were 29%, 15%, 9%, and 8% when the slit widths were 5 mm, 10 mm, 15 mm, and 20 mm, respectively. CONCLUSION: We have evaluated the scatter reduction effect of the AMS in CBCT imaging using the Monte Carlo (MC) simulations. A preliminary study based on the MCNP simulations showed a mount of scatter reduction with the proposed system.
Cone-Beam Computed Tomography

OBJECTIVE: Using the standardization of disease diagnosis of disease, and surgical procedures, the authors have made a clinical application for the analysis of inpatient data with the ability to search for information pertinent for writing of clinical articles. METHODS: A client-server system and database software was developed for networking. For clinical application, a computerized daily report has been developed. Data from Neurosurgical patients admitted at Soonchunyang University Hospital from January to December 1998 were analyzed with this system. Data for clinical articles was obtained using the search mode, information such as orbital infarction syndrome following intracranial aneurysm surgery and epidemiological analysis or geriatric neurosurgical patients. RESULTS: For the daily report it takes approximately 10 minutes to input the patients demographic information, name of disease, diagnosis and surgical procedure. The daily report also numbers and sorts the inpatients according to large categories of diagnosis, reports the ratio between inpatients and operative patients. The annual report that was obtained was very accurate and gave rapid statistics for the one year. By retrospective study for the past 18 years, we calculated the incidence of orbital infarction syndrome following intracranial aneurysm surgery as 1.4%, and also estimated the population of geriatric inpatients as 18.3% by retrospective study. CONCLUSIONS: It has been found to be most useful to make a daily and annual report for tracking and research purposes. For use in clinical articles, it can be possible to do a search of the patients using the standardized disease, diagnosis and neurosurgical procedures application and obtain pertinent information in a timely manner.
Diagnosis ; Epidemiology* ; Humans ; Incidence ; Infarction ; Inpatients ; Intracranial Aneurysm ; Neurosurgical Procedures* ; Orbit ; Retrospective Studies ; Writing

OBJECTIVE: The the international classification of disease and surgical procedure has been found to be a lengthy and time-consuming text for use by neurosurgeons. A more subject matter related classification system is needed for use by this specialty. The author has developed a more comprehensive and standardized classification system specified for diagnosis of neurological disease and neurosurgical procedures. METHODS: Standardization of disease was completed by modifying the name of disease according to that which was used for daily report past 10 years, and from textbook of neurosurgery. The fields of international coding are continued in each. Neurosurgical procedures were designated and modified according to Current Procedure Terminology 96. Client-server system will be used for networking and database software applications have been developed. RESULTS: Disease was classified in 14 large categories and 379 subcategories. Diagnosis was classified in 12 large categories and 43 subcategories. Neurosurgical procedure has 20 large and 202 subcategories. The international coding system such as ICD-10 and ICD-9CM is maintained for the diagnosis and procedures to each category. CONCLUSIONS: It could be possible to make and use a standardized database model of disease, diagnosis and neurosurgical procedures to be used by physician.
Classification ; Clinical Coding ; Diagnosis ; Epidemiology* ; International Classification of Diseases ; Neurosurgery ; Neurosurgical Procedures*

Delayed or enlarged lesions in head injury are potentially preventable events which worsen overall prognosis. We investigated the incidence and risk factors of these lesions in 240 head injured patients examined by repeated computerized tomographic(CT) scans from January 1989 to December 1990. Overall, delayed or enlarged lesions were found in 95 patients(39.6%) Intracerebral hemorrhage was the most common lesion(37 cases):Subdural(17 cases), epildural hematoma(16 cases), subdural hygroma(15 cases), cerebral swelling(6 cases), hydrocephalus(4 cases), and infarction(2 cases) followed in that order. These lesions occurred 3 days of initial scan in 64 patients(67.4%). Predictors were a low Glasgow Coma Scale score, abnormal papillary response, low or high blood pressure, hypoxia and previous infusion of large amounts of mannitol. Acute subdural hematoma was the most common initial lesion, heralding delayed or enlarged lesions in 50% of cases. Intracerebral hemtomas or contusion followed by next most common lesions. Incidence of delayed or enlarged lesions also differed according to therapy:decompressive craniectomy with these lesions in 82.8%. Mortality rate in patient who had delayed or enlarged lesions(35.5%) was 5.6 times higher than patient who did not have such lesions(6.3%). Delayed or enlarged lesions are relatively common. Patients with risk factors for delayed or enlarged lesions should be adequately monitored before overt clinical deterioration.
Anoxia ; Cerebral Hemorrhage ; Contusions ; Craniocerebral Trauma* ; Glasgow Coma Scale ; Head* ; Hematoma, Subdural, Acute ; Humans ; Hypertension ; Incidence ; Mannitol ; Mortality ; Prognosis ; Risk Factors*

The authors report a rare case of thalamic abscess in a 38-year old male who suffered from a ventricular septal defect. Preoperative axial magnetic resonance imaging(MRI) showed two ring enhancing masses on T1-weighted image and a hypointensity of dark rim on T2-weighted image. Purulent material was aspirated by computerized tomography(CT)-guided stereotactic procedure following antibiotic therapy for 3 days. No growth was obtained in the culture of the purulent material. The disturbance of left ocular movement before surgery was completely recovered. Even though the abscess wall is uniform in thickness, it is difficult to distinguish from tumor. A rim like hypointensity surrounding the mass on T2-weighted MRI is helpful in distinguishing both lesions.
Abscess* ; Adult ; Heart Septal Defects, Ventricular ; Humans ; Magnetic Resonance Imaging ; Male

The authors report a rare case of thalamic abscess in a 38-year old male who suffered from a ventricular septal defect. Preoperative axial magnetic resonance imaging(MRI) showed two ring enhancing masses on T1-weighted image and a hypointensity of dark rim on T2-weighted image. Purulent material was aspirated by computerized tomography(CT)-guided stereotactic procedure following antibiotic therapy for 3 days. No growth was obtained in the culture of the purulent material. The disturbance of left ocular movement before surgery was completely recovered. Even though the abscess wall is uniform in thickness, it is difficult to distinguish from tumor. A rim like hypointensity surrounding the mass on T2-weighted MRI is helpful in distinguishing both lesions.
Abscess* ; Adult ; Heart Septal Defects, Ventricular ; Humans ; Magnetic Resonance Imaging ; Male

To investigate the causes of death in patients with spontaneous subarachnoid hemorrhage, 460 consecutive patients with a subarachnoid hemorrhage were reviewed. Angiography was not performed in 78 patients due to poor clinical conditions or discharge against admission. Of all these patients, 54(69.2%) died, 28 from serious clinical condition, 21 from rebleeding, 3 from pulmonary complications. 1 from vasospasm, and 1 with unknown causes. Thirty-eight patients were angiographically negative, of which 6(15.8%) died, 3 due to rebleeding, 2 due to poor clinical condition, and 1 due to cerebral infarction caused by vasospasm. Of the 344 patients who had an aneurysmal subarachnoid hemorrhage. 74 were discharged against admission or died before the surgery. The remaining 270 patients underwent aneurysm clipping. Early surgery(within 72 hours after subarachnoid hemorrhage) was performed in 151 patients, intermediate surgery (between Day 4 and 7 post SAH) in 74, and late surgery(Day 8 or later after SAH) in 45. Fifty-one patients (18.9%) died after aneurysm clipping. The remaining 270 patients underwent aneurysm clipping. Early surgery(within 72 hours after subarachnoid hemorrhage) was performed in 151 patients, intermediate surgery(between Day 4 and 7 post-SAH) in 74, and late surgery(Day 8 or later after SAH) in 45, Fifty-one patients(18.9%) died after aneurysm clipping. The causes were vasospasm in 17, complications related to surgery in 13, poor clinical condition in 12, preoperative rebleeding in 7, and other systemic condition in 2. A total of 59 patients suffered at least one rebleeding after the initial hemorrhage ; these patients had a mortality rate of 76.3% and the highest rate of rebleeding occurred within the first 24 hours after initial hemorrhage. Vasospasm and rebleeding were the leading causes of mortality in addition to the initial bleeding. Predictors for mortality included poor clinical grade, early surgery in patients aged 60 years or more, and association with intracerebral hematoam, intraventricular hemorrhage, or subdural hematoma.
Aneurysm ; Angiography ; Cause of Death ; Cerebral Infarction ; Hematoma, Subdural ; Hemorrhage ; Humans ; Mortality* ; Subarachnoid Hemorrhage*

We report a rare case of scalp AVM concurrent feeding from external carotid artery and internal carotid artery, namely, superficial temporal artery and ophthalmic artery. This 20-year-old woman was seen because of serpiginous pulsatile mass in the frontal scalp, and the mass was enlarged during pregnancy. The case that feeding from the internal carotid artery branch is very rare. Angiography, MRI and MR angiography findings are presented.
Angiography ; Arteriovenous Malformations* ; Carotid Artery, External* ; Carotid Artery, Internal* ; Female ; Humans ; Magnetic Resonance Angiography ; Ophthalmic Artery ; Pregnancy ; Scalp* ; Temporal Arteries ; Young Adult

The origin and clinical importance of subdural hygroma(SDG) are still uncertain. Its pathogenetic mechanism and natural history have not yet been settled. Although the incidence of traumatic SDG has been reported to be 5-20% of posttraumatic space-occupying lesions, the true incidence has not been documented in prospective study. Therefore, authors have tried to determine the incidence of traumatic SDG prospectively during past six months. Serial computed tomography(CT) or magnetic resonance imaging(MRI) studies were done in all patients who were admitted to our department after head injuries. Data on the age, sex, Glasgow coma scale(GCS) on admission, and initial CT findings were collected and analyzed to determine the true incidence, pattern and premorbid conditions for the development of traumatic SDG. Serial CT or MRI scans were performed on the date of admission, the second to sixth hospital day, and the seventh to fourteenth hospital day. Study population consisted of 115 patients, excluding 31 expired, discharged, or transferred patients within a week. Subdural hygroma was noted in 42(35.6%) patients. It shared 45.2% of posttraumatic mass lesion. More than half (54.7%) of patients aged 40 or more had subdural hygromas. They were generally delayed lesions, due to the fact that most of them(81%) were observed at four days or more after the injury. All hygromas were located at the frontal or fronto-temporo-parietal regions. Bilaterality was seen in 54.7%. SDGs occurred earlier when the age of the patients were 40 years old or more(p=0.037). It occurred earlier when the initial CT scans were normal, when there was no accompanying traumatic intracranial lesions, and high GCS on admission. However, these differences were statistically not significant(p>0.05). These results suggest that the premorbid conditions for the development of subdural hygroma were sufficient potential subdural space and separation of the dural border cell layer, although former seemed to be more important that the later. Osmotic dehydration in the aged victims should be serially reevaluated, because the subdural hygroma may develop when the intracranial pressure is excessively low.
Adult ; Coma ; Craniocerebral Trauma ; Dehydration ; Epidemiology ; Humans ; Incidence* ; Intracranial Pressure ; Lymphangioma, Cystic ; Magnetic Resonance Imaging ; Natural History ; Prospective Studies* ; Subdural Effusion* ; Subdural Space ; Tomography, X-Ray Computed

Despite recent advances in the care of such patients, subarachnoid haemorrhage(SAH) due to ruptured intracerebral aneurysm continues to carry a high rate of morbidity and mortality. During the acute phase of SAH, various factors can aggravate a patients initial good neurological state, and every effort should thus be made to prevent such occurrences. Although not a major problem, seizure is a well known factor influencing the course of the disease. The authors studied 476 cases of SAH occurring during the preceding eight-year period and reported the incidence of seizure, the risk factors which evoke it, and the optimal time required to prevent it. The incidence was 11%, and 48% of seizures occurred within three days of SAH. The risk factors were Hunt-Hess grade at admission, degree of neurologic deficit, and the presence and timing of rebleeding. Regardless of initial grade, seizure led to a poorer outcome. We conclude that seizure in aneurysmal subarachnoid hemorrhage occurs during the early stage of the disease and aggravates the prognosis. The recognition of risk factors and early prevention of seizure are thus necessary.
Aneurysm ; Humans ; Incidence ; Intracranial Aneurysm* ; Mortality ; Neurologic Manifestations ; Prognosis ; Risk Factors ; Seizures* ; Subarachnoid Hemorrhage