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*

A series of 89 patients diagnosed between 1988 and 1993 with computerized tomography(CT) as having subdural hematoma was studied retrospectively in order to evaluate the age of the subdural hematomas according to its appearance on CT scans. In all the patients, the interval from onset of injury to performance of CT scans was more than 2 days. The patients were divided into 4 groups based on the difference in density of the hematoma as seen on the CT scans;hyperdensity(16.9%), isodensity(30.3%), hypodensity(19.1%), and mixed-density(33.7%) groups. The mean interval from onset of injury to diagnosis in hyperdensity, hypodensity, mixed density, and isodensity groups was 15.7+/-18.3 days, 18.8+/-27.9 days, 35.6+/-62.1 days, and 47.6+/-52.1 days, respectively. The configuration of the hematomas on CT scans was crescentic in 74.2%, planoconvex in 12.4%, and biconvex in 13.5%. As the interval became longer, the hematomas tended to take on a planoconvex or biconvex shape rather than the crescentic shape;when the interval from onset of injury to diagnosis was within 7 days, crescentic shape was observed in 91%, within 8 to 21 days, 69%, and over 21 days, 58%. It is concluded from these findings that subdural hematomas undergo a progressive change in their attenuation as the hematomas age, changing from the initial hyperdense stage, go through a hypodense stage, and eventually to an isodense stage. These changes of attenuation values correlates fairly well with the rebleeding theory. The appearance of the hematomas as seen on CT scans also tended to change from the initial crescentic shape to the planoconvex or biconvex shape with time. However, given the possible variations of attenuation values and shapes of subdural hematomas, assumption of the age of the hematomas based on CT findings alone should be made with caution.
Diagnosis ; Hematoma ; Hematoma, Subdural* ; Hematoma, Subdural, Chronic ; Humans ; Retrospective Studies ; Tomography, X-Ray Computed

No abstract available.
Neoplasm Metastasis*

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*

OBJECTIVE: Although posterior wiring techniques have been commonly used with good results in treating the traumatic atlantoaxial instabilities, screw fixation technique has been gaining popularity to secure atlantoaxial arthrodesis in recent years. The purpose of this study is to compare the surgical results of posterior arthrodesis for the traumatic atlantoaxial instability between these two methods. METHODS: Twenty patients underwent 21 procedures over a 6-year period with a mean follow-up of 23 months. The most common condition of traumatic atlantoaxial instability was dens fracture(15 patients) followed by transverse atlantal ligament injury(4 patients), and traumatic os odontoideum(2 patients). Thirteen posterior wiring and eight posterior screw fixations were performed. Among 13 wiring methods, nine Galli fusions, two occipito-cervical fusions, one Brooks fusion, and one C1-C3 fusion were done. RESULTS: No patient developed neurological worsening after surgery. Compared to wire method, all patients of screw group had significant pain reduction when the patients was younger than 50 years old(p=0.01). The postoperative changes in distances of space available for cord(SAC) was not statistically significant between wire and screw methods(p=0.7). The rate of complication(23% in wire vs 25% in screw) was comparable to two methods. Although two screw malposition(25%) among screw fixations were developed, all revealed solid fusion without additional surgeries. The rate of fusion(85% in wire vs 100% in screw) was excellent in screw group. Postoperative loss of reduction, including redisplacement and kyphosis, was present only in wire group(31%). Two(15%) of wire fusions had redisplacement; both of these patients were type 2 dens fracture. Three procedures(23%) of wire fusions resulted in kyphotic change which occurred when delayed surgeries were done between 40 days and 90 days(mean: 63 days) after trauma. CONCLUSION: Considering both reduction loss and fusion rate, wire method caused more spinal deformity than screw method(38% vs 0%). This study demonstrates that screw method is a better surgical option for management of traumatic atlantoaxial instability.
Arthrodesis* ; Congenital Abnormalities ; Follow-Up Studies ; Humans ; Kyphosis ; Ligaments

No abstract available.
Prognosis* ; Subarachnoid Hemorrhage, Traumatic*

To investigate the clinical significance of intracerebral hematoma(ICH) in patients with spontaneous subarachnoid hemorrhage(SAH), the authors reviewed 527 consecutive patients with SAH during the past 7 years. Computed tomography(CT) visible ICH was found in 115 patients(21.8%). In patients over 50 years old, ICH was found more frequently than patients aged 50 years or less(p<0.05). Patients with ICH had a higher incidence of intraventicular hemorrhage or rebleeding compared with patients without ICH(p<0.005). No significant association was found between pre-existing hypertension and ICH. Patients with ICH were in higher Hunt and Hess Grade(HHG) on admission(p<0.005), and had a poorer outcome compared with patients without ICH(p<0.005). Seventy-nine(20.2%) among the 392 patients with aneurysmal subarachnoid hemorrhage had ICHs, of whom the frequent site of aneurysm was the middle cerebral artery in 45.3%, anterior cerebral artery in 17.9%. The rate of good recovery in these patients was significantly low compared with patients without ICH. The mortality in 313 operated patients with aneurysmal subarachnoid hemorrhage was 36.4% in patients with ICH and 14.6% in those without ICH (p<0.005). Particulary, in the patients with middle cerebral artery or internal carotid artery aneurysm, ICH had a significant influence on the good recovery and mortality(p<0.005). Even though the surgical mortality of the patients with large hematoma more than 30 cc in amount was 64.7%, one half of the survivors showed good recovery. This study suggests that the prognosis after subarachnoid hemorrhage is poorer in patients with an ICH. Although the initial clinical grade is an important prognostic factor, the prognosis for patients in the same initial clinical grade is poorer when ICH is accompanied. In regard with an increased incidnece of rebleeding episode and an increased intracranial pressure in the patients with ICHs, we emphasize the importance of early surgical intervention.
Aneurysm ; Anterior Cerebral Artery ; Carotid Artery, Internal ; Hematoma* ; Hemorrhage ; Humans ; Hypertension ; Incidence ; Intracranial Pressure ; Middle Aged ; Middle Cerebral Artery ; Mortality ; Prognosis ; Subarachnoid Hemorrhage* ; Survivors

We present a series of 97 patients with spinal cord injury. Those patients were treated at Soonchunhyan University Chonan Hospital during six-year-period(January 1986-December 1992), and followed up for at least 3 months. They were divide into four groups ; complete-surgical, complete-conservative, partial-surgical, and partial-conservative. Male to female ratio was 3.6:1, and the peak age was the fifth decade. Passenger's traffic accident(46%) was the most common cause of injury and fall/slip(39%) followed next. Level of spinal injury was cervical in 51%, thoracic in 29%, lumbar in 13%, and others in 7%. Type of injury was fracture-dislocation in 31%, dislocation in 19%, compression fracture in 19%, burst fracture in 18%, cord injury without bony lesion in 7%, and others in 7%. Cord injury was complete in 36 patients(37%) and partial in 61 patients(63%). Surgery was performed in 20 patients with complete cord injury and 34 patients with partial injury. Majority of operations were performed for spinal stability, and posterior instrumentation was the most commonly used operative method. The mean neurotrauma motor index on admission was 44.1 in the complete-surgical group, 39.5 in complete-conservative group, 70.1 in partial-surgical group, and 63.2 in partial-conservative group. It improved to 52.5, 50.3, 90.4, 80.3 at 3 months, and 53.4, 51.7, 91.8, 82.0 at final examination(mean follow-up period was 182.2 days), respectively. The mean values of the final index were higher in the surgically treated groups than the conservatively treated groups, but these differences were not statistically significant(student t-test p>0.1) The mean recovery rate was 14.2% in the complete-surgical group, 17.7% in complete-conservative group, 66.1% in partial-surgical group, and 46.1% in partial-conservative group at 3 months. It improved to 16.6%, 19.3%, 70.0%, and 48.7% at final examination, respectively. The mean recovery rates were higher in the partially injured groups than the completely injured groups(student t-test, p<0.01), regardless the methods of treatment. The final neurotrauma motor index was significantly(regression analysis, p<0.01) related to the initial index except the partial-surgical group. Neurotrauma motor index was a useful method for assessing the injury severity, comparing the recovery rate and predicting prognosis.
Chungcheongnam-do ; Dislocations ; Female ; Follow-Up Studies ; Fractures, Compression ; Humans ; Male ; Prognosis* ; Spinal Cord Injuries* ; Spinal Cord* ; Spinal Injuries