Optimal beam quality for chest flat panel detector system: realistic phantom study.

OBJECTIVE: To investigate optimal beam quality for chest flat panel detector (FPD) system by semi-quantitatively assessment using a realistic lung phantom. MATERIALS AND METHODS: Chest FPD radiographs were obtained on a realistic lung phantom with simulated lung opacities using various X-ray tube voltage levels (90-140 kV) with/without copper filter. Entrance skin dose was set to maintain identical for all images (0.1 mGy). Three chest radiologists unaware of the exposure settings independently evaluated the image quality of each simulated opacity and normal structure using a 5-point scale (+ 2: clearly superior to the standard; + 1: slightly superior to the standard; 0: equal to the standard; - 1: slightly inferior to the standard; - 2: clearly inferior to the standard). The traditional FPD image obtained at a tube voltage of 120 kV was used as the standard. The scores of image quality were statistically compared using the Wilcoxon rank test with Bonferroni correction. RESULTS: FPD images using 90-kV shot with copper filter were superior to the traditional 120-kV shot without filter with respect to the visibility of vertebra, pulmonary vessels, and nodules overlapping diaphragm and heart (p < 0.05). There was no significant difference with respect to the visibility of all other simulated lung opacities (lung nodules except for overlying diaphragm/heart and honeycomb opacity) between each tube voltage level with/without copper filter and the traditional 120-kV shot without filter. CONCLUSION: Image quality of FPD images using 90 kV with copper filtration is superior to that using standard tube voltage when dose is identical. KEY POINTS: • FPD image quality using 90 kV with filter is superior to that using traditional beam. • Ninety-kilovolt shot with copper filter may be suitable for chest FPD image. • Clinical study dealing with chest FPD beam optimization would be warranted.

Detection of lung carcinoma with predominant ground-glass opacity on CT using temporal subtraction method.

PURPOSE: To evaluate the usefulness of the CT temporal subtraction (TS) method for the detection of the lung cancer with predominant ground-glass opacity (LC-pGGO). MATERIALS AND METHODS: Twenty-five pairs of CT and their TS images in patients with LC-pGGO (31 lesions) and 25 pairs of those in patients without nodules were used for an observer performance study. Eight radiologists participated and the statistical significance of differences with and without the CT-TS was assessed by JAFROC analysis. RESULTS: The average figure-of-merit (FOM) values for all radiologists increased to a statistically significant degree, from 0.861 without CT-TS to 0.912 with CT-TS (p < .001). The average sensitivity for detecting the actionable lesions improved from 73.4 % to 85.9 % using CT-TS. The reading time with CT-TS was not significantly different from that without. CONCLUSION: The use of CT-TS improves the observer performance for the detection of LC-pGGO. KEY POINTS: • CT temporal subtraction can improve the detection accuracy of lung cancer. • Reading time with temporal subtraction is not different from that without. • CT temporal subtraction improves observer performance for ground-glass/subsolid nodule detection.

Evaluation of the R2* value in invasive ductal carcinoma with respect to hypoxic-related prognostic factors using iterative decomposition of water and fat with echo asymmetry and least-squares emission (IDEAL).

OBJECTIVE: To correlate the R2* value obtained by iterative decomposition of water and fat with echo asymmetry and least-squares emission (IDEAL) with fibrotic focus (FF), microvessel density and hypoxic biomarker (HIF-1α) in breast carcinoma. METHODS: Forty-two patients who were diagnosed with invasive ductal carcinoma (IDC) of the breast underwent breast MRI including IDEAL before surgery. The entire region of interest (ROI) was delineated on the R2* map, and average tumour R2* value was calculated for each ROI. Histological specimens were evaluated for the presence of FF, the microvessel density (the average microvessel density and the ratio of peripheral to central microvessel density), and the grading of HIF-1α. RESULTS: FF was identified in 47.6% (20/42) of IDCs. Average R2* value for IDC with FF (42.4±13.2 Hz) was significantly higher than that without FF (28.5±13.9 Hz) (P = 0.01). Spearman rank correlation suggested that the average R2* value correlated with the grade of HIF-1α and the ratio of peripheral to central microvessel density for IDCs (P < 0.001). CONCLUSION: Quantification of tumour R2* using IDEAL is associated with the presence of FF and the overexpression of HIF-1α, and may therefore be useful in predicting hypoxia of breast carcinoma. KEY POINTS: • R2* value obtained by IDEAL correlates with the overexpression of HIF-1α. • R2* value obtained by IDEAL is associated with fibrotic focus. • R2* quantification may be useful in predicting hypoxia of breast carcinoma.

Prediction of Femoral Neck Strength in Patients with Diabetes Mellitus with Trabecular Bone Analysis and Tomosynthesis Images.

Purpose To determine trabecular bone analysis values by using tomosynthesis images in determining femoral neck strength in patients with diabetes mellitus and compare its parameters between vertebral compression fracture and nonfracture groups. Materials and Methods The institutional review board approved this study, and written informed consent was obtained from all patients. Forty-nine patients with diabetes mellitus were included. Within 1 week, patients underwent dual x-ray absorptiometry (DXA), tomosynthesis, and computed tomography (CT) covering the T10 vertebral body to the hip joints. The trabecular patterns of tomosynthesis images were extracted, and the total strut length, bone volume per tissue volume, and five textural features (homogeneity, entropy, correlation, contrast, and variance) were obtained as the indices of tomosynthesis images. Failure load of the femoral neck, which was determined with the CT-based finite-element method (FEM), was used as the reference standard for bone strength. A forward stepwise multiple regression analysis for evaluating the availability of the tomosynthesis image indices was performed. The bone mineral density (BMD) at DXA and tomosynthesis image indices were compared between the vertebral compression fracture (n = 16) and nonfracture groups (n = 33) according to Genant semiquantitative morphometry methods by using one-way analysis of variance. Results The combination of BMD with the bone volume per tissue volume at the principal tensile group and the correlation at the principal compressive group showed the highest correlation to the failure load at CT FEM, and the correlation (r2 = 0.83) was higher than that between the failure load and the BMD alone (r2 = 0.76; P < .001). The averages of the bone volume per tissue volume and entropy at the principal tensile group in the vertebral compression fracture group were lower than those in the nonfracture group (P = .017 and P = .029, respectively), but there was no difference in BMD. Conclusion Tomosynthesis-based trabecular bone analysis is technically feasible and, in combination with BMD measurements, can potentially be used to determine bone strength in patients with diabetes mellitus. © RSNA, 2016 Online supplemental material is available for this article.

Effects of Brain Temperature on Cerebrovascular Autoregulation During the Acute Stage of Severe Traumatic Brain Injury.

The pressure reactivity index (PRx) is calculated as a moving correlation coefficient between intracranial pressure (ICP) and mean arterial blood pressure (MABP), and this analytical value is viewed as reflecting a vasomotor response to MABP variability. At present, the factors influencing the PRx value during the acute stage of traumatic brain injury (TBI) are not known. We observed significant cases where changes in the calculated value of PRx seemed to be influenced by changes in brain temperature during the course of acute stage TBI. In one case, a patient was treated for 72 h with therapeutic brain hypothermia after a decompressive hemicraniectomy. During the hypothermic condition, the mean value of PRx was -0.019; however, after gradual rewarming, the value of PRx increased drastically, and the mean value during the rewarming period, when the brain temperature exceeded 35 °C, was 0.331. Similarly, in another case where the patient underwent therapeutic brain hypothermia, the PRx showed a mean value of -0.038 during the hypothermic condition, and a mean value of 0.052 during the rewarming period. In both cases, a trend toward a negative correlation between ICP and MABP during brain hypothermia shifted to a positive correlation upon rewarming.

Strategies and Pitfalls of Motor-Evoked Potential Monitoring during Supratentorial Aneurysm Surgery.

BACKGROUND: The aims of this study were to reveal the strategies and pitfalls of motor-evoked potential (MEP) monitoring methods during supratentorial aneurysm surgery, and to discuss the drawbacks and advantages of each method by reviewing our experiences. METHODS: Intraoperative MEP monitoring was performed in 250 patients. Results from 4 monitoring techniques using combinations of 2 stimulation sites and 2 recording sites were analyzed retrospectively. RESULTS: MEP was recorded successfully in 243 patients (97.2%). Direct cortical stimulation (DCS)-spinal recorded MEP (sMEP) was used in 134 patients, DCS-muscle recorded MEP (mMEP) in 97, transcranial electrical stimulation (TES)-mMEP in 11 and TES-sMEP in 1. TES-mMEP during closure of the skull was used in 21 patients. DCS-mMEP was able to detect waveforms from upper and/or lower limb muscles. Alternatively, DCS-sMEP (direct [D]-wave) could accurately estimate amplitude changes. A novel "early warning sign" indicating ischemia was found in 21 patients, which started with a transiently increased amplitude of D-wave and then decreased after proximal interruption of major arteries. False-negative findings in MEP monitoring in 2 patients were caused by a blood insufficiency in the lenticulostriate artery and by a TES-sMEP recording, respectively. CONCLUSIONS: The results of this study suggest that to perform accurate MEP monitoring, DCS-mMEP or DCS-sMEP recording should be used as the situation demands, with combined use of TES-mMEP recording during closure of the skull. DCS-sMEP is recommended for accurate analysis of waveforms. We also propose a novel "early warning sign" of blood insufficiency in the D-wave.

[Fact-finding survey on regional healthcare services for patients with epilepsy based on a questionnaire administered to public health centers in Japan].

OBJECTIVES: Epilepsy is a common chronic neurological disorder characterized by recurrent unprovoked seizures. The prevalence of epilepsy is about 1%, and its incidence is increasing with the aging population. In addition to their medical problems, epilepsy patients face many social problems, including schooling, working, and maintaining their driver's licenses. However, these problems are not fully recognized by the regional healthcare centers (HCCs), and the inadequacy of collaboration between medical services, healthcare, and welfare is sometimes pointed out. Under these circumstances, this fact-finding survey was administered in the form of a questionnaire to HCCs across the nation for the purpose of improving the support system and educational activities for epilepsy in Japan. METHODS: A mail-back survey on regional healthcare services for epilepsy patients was sent out to 490 HCCs across the nation. Public health nurses (PHNs) responded to the self-completed questionnaire on behalf of each HCC. The questionnaire was comprised of the presence or absence of consultations on epilepsy, content of the consultations, and holding of workshops, lectures, or conferences in the community covered by the HCC. RESULTS: We obtained responses from 347 HCCs (response rate 71%). Seventy-three percent of the PHNs had experience with consultations regarding the medical and healthcare issues associated with epilepsy. However, only 10% of the PHNs responded that they could provide appropriate consultation for these issues. The content of the consultations mainly included medical services, clinical symptoms of epilepsy, and anxieties about their social life and their future. Workshops, lectures, or conferences on epilepsy were held for residents or health and welfare professionals in only 8% of the communities. This percentage is lower than those (21-70%) for other intractable or mental disorders that are mainly managed by HCCs (P<0.01). On the other hand, 76% of PHNs in the HCCs felt the need for knowledge about epilepsy, and 60% wanted to join the epilepsy educational programs. CONCLUSION: Although many PHNs belonging to HCCs conduct consultations regarding epilepsy-related issues, many feel they cannot adequately respond to these issues. Furthermore, they feel the need for further knowledge about epilepsy but are not able to gain such knowledge because of financial and geographical restrictions. To improve these situations, regional education programs for epilepsy should be established in each local municipality in the future with support provided by medical facilities, regional medical associations, the Japan Epilepsy Society, and the Government.

Temporal subtraction method for lung nodule detection on successive thoracic CT soft-copy images.

PURPOSE: To assess the effects of a new computed tomographic (CT) temporal subtraction (TS) method on radiologist performance in lung nodule detection on thin-section CT images. MATERIALS AND METHODS: The institutional review board approved this study, and the informed consent requirement was waived. Fifty pairs (current and previous CT images) of standard-dose 2-mm thin-section CT images and corresponding CT TS images were used for an observer performance study. Two thoracic radiologists identified 30 nodules ranging in size from 5 to 19 mm, and these nodules served as the reference standard of actionable nodules (noncalcified nodules larger than 4 mm). Eight radiologists (four attending radiologists, four radiology residents) participated in this observer study. Ratings and locations of lesions determined by observers were used to assess the significance of differences between radiologists' performances without and with the CT TS images in jacknife free-response receiver operating characteristics analysis. RESULTS: Average figure of merit values increased significantly for all radiologists (from 0.838 without CT TS images to 0.894 with CT TS images [P = .033]). Average sensitivity for detection of actionable nodules was improved from 73.4% to 83.4%, with a false-positive rate of 0.15 per case, by using CT TS images. The reading time with CT TS images was not significantly different from that without. CONCLUSION: The novel CT TS method would increase observer performance for lung nodule detection without considerably extending the reading time.

Changes in glutamate concentration, glucose metabolism, and cerebral blood flow during focal brain cooling of the epileptogenic cortex in humans.

OBJECTIVE: Recently, focal brain cooling (FBC) was proposed as a method for treating refractory epilepsy. However, the precise influence of cooling on the molecular basis of epilepsy has not been elucidated. Thus the aim of this study was to assess the effect of FBC on glutamate (Glu) concentration, cerebral blood flow (CBF), and glucose metabolism in patients with intractable epilepsy. METHODS: Nine patients underwent FBC at 15°C for 30 min prior to cortical resection (n = 6) or hippocampectomy (n = 3). Measurement of metabolites and CBF, as well as electrocorticography (ECoG), was performed. RESULTS: Epileptic discharge (ED), as observed by ECoG, disappeared in the cooling period and reappeared in the rewarming period. Glu concentrations were high during the precooling period and were reduced to 51.2% during the cooling period (p = 0.025). Glycerol levels showed a similar decrease (p = 0.028). Lactate concentration was high during the precooling period and was reduced during the cooling period (21.3% decrease; p = 0.005). Glucose and pyruvate levels were maintained throughout the procedure. Changes in CBF were parallel to those observed by ECoG. SIGNIFICANCE: FBC reduced EDs and concentrations of Glu and glycerol. This demonstrates the neuroprotective effect of FBC. Our findings confirm that FBC is a reasonable and optimal treatment option for patients with intractable epilepsy.

Tomosynthesis of the wrist and hand in patients with rheumatoid arthritis: comparison with radiography and MRI.

OBJECTIVE: The purpose of this article is to compare tomosynthesis with radiography and MRI of the wrist and hand for evaluating bone erosion in patients with rheumatoid arthritis (RA). MATERIALS AND METHODS: Twenty consecutive patients with an established diagnosis of RA and five control patients were included in this study. They underwent radiography, tomosynthesis, and MRI of the bilateral hand and wrist within a week. The mean total dose of radiography and tomosynthesis was 0.13 and 0.25 mGy, respectively. MRI evaluation was performed according to the Outcome Measures in Rheumatology Clinical Trials recommendations. Bone erosion on images from the three modalities was independently reviewed by two certificated radiologists with a 4-point scale (0, normal; 1, discrete erosion; 2, < 50% of the joint surface; and 3, ≥ 50% of the joint surface). RESULTS: The detection rates of bone erosion for radiography, tomosynthesis, and MRI were 26.5%, 36.1%, and 36.7%, respectively. Significantly more bone erosions were revealed with tomosynthesis and MRI than with radiography (p < 0.01). When MRI was used as the reference standard, the sensitivity, specificity, and accuracy were 68.1%, 97.5%, and 86.7%, respectively, for radiography and 94.8%, 97.8%, and 96.7%, respectively, for tomosynthesis. Interobserver agreement (kappa value) for bone erosion was good to excellent on tomosynthesis and MRI for all joints (0.65-1.00 and 0.68-1.00, respectively), whereas it was slight to fair on radiography for some carpal bones and bases of metacarpal bones (0.22-0.56). CONCLUSION: Tomosynthesis is superior to radiography and almost comparable to MRI for the detection of bone erosion in patients with RA.

Cooling treatment transiently increases the permeability of brain capillary endothelial cells through translocation of claudin-5.

The blood-brain-barrier (BBB) is formed by different cell types, of which brain microvascular endothelial cells are major structural constituents. The goal of this study was to examine the effects of cooling on the permeability of the BBB with reference to tight junction formation of brain microendothelial cells. The sensorimotor cortex above the dura mater in adult male Wistar rats was focally cooled to a temperature of 5 °C for 1 h, then immunostaining for immunoglobulin G (IgG) was performed to evaluate the permeability of the BBB. Permeability produced by cooling was also evaluated in cultured murine brain endothelial cells (bEnd3) based on measurement of trans-epithelial electric resistance (TEER). Immunocytochemistry and Western blotting of proteins associated with tight junctions in bEnd3 were performed to determine protein distribution before and after cooling. After focal cooling of the rat brain cortex, diffuse immunostaining for IgG was observed primarily around the small vasculature and in the extracellular spaces of parenchyma of the cortex. In cultured bEnd3, TEER significantly decreased during cooling (15 °C) and recovered to normal levels after rewarming to 37 °C. Immunocytochemistry and Western blotting showed that claudin-5, a critical regulatory protein for tight junctions, was translocated from the membrane to the cytoplasm after cooling in cultured bEnd3 cells. These results suggest that focal brain cooling may open the BBB transiently through an effect on tight junctions of brain microendothelial cells, and that therapeutically this approach may allow control of BBB function and drug delivery through the BBB.

Effect of the neutrophil elastase inhibitor sivelestat on perioperative inflammatory response after pediatric heart surgery with cardiopulmonary bypass: a prospective randomized study.

Cardiopulmonary bypass (CPB) elicits a systemic inflammatory response. The neutrophil elastase inhibitor sivelestat is known to suppress this systemic inflammatory response, which can eventually result in acute organ failure. The prophylactic effect of sivelestat on acute lung injury, especially in pediatric cardiac surgery, remains unclear. This prospective double-blind, randomized study evaluated the perioperative prophylactic effect of sivelestat in patients undergoing elective pediatric open heart surgery with CPB. Thirty consecutive patients, weighing 5-10 kg and undergoing open heart surgery with CPB, were assigned to sivelestat (n = 15) or control (n = 15) groups. From CPB initiation to 24 h after surgery, patients in the sivelestat group received a continuous intravenous infusion of 0.2 mg/kg/h sivelestat, whereas patients in the control group received the same volume of 0.9% saline. Blood samples were collected, and levels of interleukin (IL)-6, IL-8, tumor necrosis factor alpha, polymorphonuclear elastase (PMN-E), C-reactive protein (CRP), as well as the white blood cell (WBC) count, platelet count, and neutrophil count (NC) were measured. PMN-E levels, IL-8 levels, WBC count, NC, and CRP levels were significantly lower, and platelet count was significantly higher in the sivelestat group, according to repeated two-way analysis of variance. The activated coagulation time was significantly shorter in the sivelestat group, similarly, blood loss was significantly less in the sivelestat group. In conclusion, Sivelestat attenuates perioperative inflammatory response and clinical outcomes in patients undergoing pediatric heart surgery with CPB.

Cooling of the epileptic focus suppresses seizures with minimal influence on neurologic functions.

PURPOSE: Focal brain cooling is effective for suppression of epileptic seizures, but it is unclear if seizures can be suppressed without a substantial influence on normal neurologic function. To address the issue, a thermoelectrically driven cooling system was developed and applied in free-moving rat models of focal seizure and epilepsy. METHODS: Focal seizures limited to the unilateral forelimb were induced by local application of a penicillin G solution or cobalt powder to the unilateral sensorimotor cortex. A proportional integration and differentiation (PID)-controlled, thermoelectrically driven cooling device (weight of 11 g) and bipolar electrodes were chronically implanted on the eloquent area (on the epileptic focus) and the effects of cooling (20, 15, and 10°C) on electrocorticography, seizure frequency, and neurologic changes were investigated. KEY FINDINGS: Cooling was associated with a distinct reduction of the epileptic discharges. In both models, cooling of epileptic foci significantly improved both seizure frequency and neurologic functions from 20°C down to 15°C. Cooling to 10°C also suppressed seizures, but with no further improvement in neurologic function. Subsequent investigation of sensorimotor function revealed significant deterioration in foot-fault tests and the receptive field size at 15°C. SIGNIFICANCE: Despite the beneficial effects in ictal rats, sensorimotor functions deteriorated at 15°C, thereby suggesting a lower limit for the therapeutic temperature. These results provide important evidence of a therapeutic effect of temperatures from 20 to 15°C using an implantable, hypothermal device for focal epilepsy.

[Insular psammomatous meningioma presenting intractable complex partial seizures].

We describe a 30-year-old female with intractable symptomatic epilepsy caused by an insular calcified mass, which was histologically proved as psammomatous meningioma. Seizures were described as consciousness impairment, motionless stare and automatism. After total removal of the tumor with a neuronavigation system and motor evoked potential (MEP) monitoring, seizures completely disappeared without neurological deficit. We emphasize that insular meningioma presents complex partial seizures which mimic medial temporal lobe epilepsy and seizures are controlled by total resection of the tumor.

Endovascular Treatment Using a Small Amount of Contrast Medium in a Patient with a Posterior Communicating Artery Ruptured Dissecting Aneurysm and Chronic Kidney Disease: A Case Report.

Objective: We report a rare case of a patient with a ruptured posterior communicating artery (P-com A) dissecting aneurysm and chronic kidney disease (CKD) treated by endovascular embolization using a small amount of contrast medium. Case Presentation: An 88-year-old female patient had sudden onset of headache and vomit due to subarachnoid hemorrhage. MRI revealed a ruptured dissecting aneurysm of the right P-com A. The patient had CKD of severity grade 4. Endovascular treatment was performed using only 10 mL of diluted contrast medium with injection through a microcatheter. The postoperative course was uneventful, and no deterioration of renal function occurred. Conclusion: With minimal amount of contrast medium, endovascular treatment could be safely and effectively performed for patients with P-com A dissecting aneurysms and severe CKD.

Idiopathic dissecting cerebral aneurysm of the distal anterior cerebral artery in an infant successfully treated with aneurysmectomy: illustrative case.

BACKGROUND: Idiopathic dissecting cerebral aneurysms (IDCAs) are male dominant but are extremely rare in children. Many IDCAs in children are located in the posterior cerebral artery and the supraclinoid internal cervical artery. No cases of IDCA of the distal anterior cerebral artery (ACA) have been reported. OBSERVATIONS: A previously healthy 7-month-old boy experienced afebrile seizures and presented at the authors' hospital 1 week after the first seizure. He was not feeling well but had no neurological deficits. The authors diagnosed a ruptured aneurysm of the right distal ACA based on imaging results. He underwent emergency craniotomy to prevent re-rupture of the aneurysm. Using intraoperative indocyanine green videoangiography, the authors confirmed peripheral blood flow and then performed aneurysmectomy. Pathological examination of the aneurysm revealed a thickened intima, fragmentation of the internal elastic lamina, and a hematoma in the aneurysmal wall. The authors ultimately diagnosed IDCA because no cause was indicated, including a history of trauma. The boy recovered after surgery and was subsequently discharged with no complications. LESSONS: The authors reported, for the first time, IDCA of the distal ACA in an infant. The trapping technique is often used for giant fusiform aneurysms in infants. Indocyanine green videoangiography is useful for evaluating peripheral blood flow during trapping in this case.

Establishment of a new conditionally immortalized human brain microvascular endothelial cell line retaining an in vivo blood-brain barrier function.

The breakdown of the blood-brain barrier (BBB) has been considered to be a key step in the disease process of a number of neurological disorders such as cerebral ischemia and Alzheimer's disease. Many in vitro BBB models derived from animal tissues have been established to elucidate the mechanism of BBB insufficiency. However, only a few human immortalized in vitro BBB models have been reported. In the present study, a temperature-sensitive SV40-T antigen was introduced to immortalize cells using a retrovirus to obtain a better human in vitro BBB model which sustains physiological properties. This endothelial cell (EC) line, termed TY08, showed a spindle-shaped morphology. The cells expressed all key tight junctional proteins, such as occludin, claudin-5, zonula occludens (ZO)-1 and ZO-2 at their cell-to-cell boundaries, and had low permeability to inulin across its monolayer. The cells also expressed various influx and efflux transporters and exhibited the functional expression of p-glycoprotein. Furthermore, the TY08 cells grew and proliferated well under the permissive temperature and stopped growing under the non-permissive temperature to serve as physiological ECs forming the BBB. Thus, conditionally immortalized TY08 cells retaining the in vivo BBB functions should facilitate analyses for determining the pathophysiology of various neurological diseases.

Factors influencing spinal canal stenosis in patients with long-term controlled hydrocephalus treated with cerebrospinal fluid shunt.

PURPOSE: Spinal canal stenosis (CS) occurs in patients with hydrocephalus who are treated with cerebrospinal fluid (CSF) shunting. The pathophysiology of CS comprises CSF overdrainage. We analyzed the incidence of CS and the factors causing it. METHODS: Thirty-three patients who underwent ventriculoperitoneal shunt during childhood visited the Outpatient Department in Yamaguchi University Hospital in 2006. Diameters of spinal canal at C(4) were measured. Treatment procedure, age, and type of hydrocephalus in the patients with CS were compared with those without CS. RESULTS: Of the 33 patients, 10 (30.3%) presented CS, and two (6.1%) were symptomatic. A low-pressure valve caused CS with a significantly higher incidence than a medium- or high-pressure valve (60.0% vs. 17.4%, P < 0.05). Although the difference was not significant, the average age of shunt insertion for a patient with CS was slightly less (0.87 +/- 0.99) than for a patient without CS (1.63 +/- 1.58). No differences in the CS incidence were observed between obstructive and communicating hydrocephalus. CONCLUSION: In order to prevent CS, the hydrocephalus should be appropriately controlled by using a medium- or high-pressure valve until the diameter of the spinal canal reaches the required level. Adjustment of the programmable valve with the patient's growth should be ideal.

[Cyst formation after radiosurgery for brain arteriovenous malformation treated with cystoperitoneal shunt].

Gamma knife and CyberKnife radiosurgery are well established and less invasive treatments for arteriovenous malformation. Delayed cyst formation is a rare but well-known complication of radiosurgery for arteriovenous malformations. The optimal treatment of cysts forming after radiosurgery remains debatable. We present a case of cyst formation after radiosurgery for brain arteriovenous malformation that was treated with a cystoperitoneal shunt (C-P shunt). A 36-year-old woman presented with left hemiparesis and numbness. Computed tomography (CT) revealed intracranial hemorrhage in the right basal ganglia. Digital subtraction angiography revealed arteriovenous malformation in the brain. Intravascular embolization was performed three times and radiosurgery was performed twice, whereby complete obliteration of the nidus was achieved. Six and a half years later, routine follow-up magnetic resonance imaging revealed cyst formation, and the patient gradually developed left hemiparesis. First, we performed stereotactic cyst aspiration. This initially resulted in a reduction in the size of the cyst and disappearance of left hemiparesis, but within a short time, the cyst increased in size again and there was recurrence of hemiparesis. Therefore, an Ommaya reservoir was established; aspiration of the cyst through this reservoir brought about an initial reduction in cyst size and alleviation of symptoms; however, no further reduction in cyst size or improvement in symptoms could be achieved. Twenty months after the placement of the Ommaya reservoir, we performed a C-P shunt operation. After the operation, further reduction in the cyst size and complete symptomatic recovery were observed.

Cause of hematic cysts of the orbit: increased fibrinolysis and immunohistologic expression of tissue plasminogen activator.

PURPOSE: Hematic cysts of the orbit are relatively uncommon. These cysts expand gradually, leading to progressive orbital symptoms. To clarify the cause of hematic cyst, especially the mechanisms leading to its gradual expansion, we investigated the immunohistologic expression of tissue-type plasminogen activator (tPA), a key enzyme of fibrinolysis, in cases of hematic cysts. DESIGN: Retrospective small case series. PARTICIPANTS: Three patients with hematic cyst of the orbit were studied. METHODS: Three surgically removed hematic cysts were studied from a histologic perspective, including immunohistochemistry for tPA. The cyst content was also analyzed chemically. MAIN OUTCOME MEASURES: The pathologic features of hematic cyst of the orbit, expression of tPA in the cyst wall, and coagulation-fibrinolytic factors in the content of the cyst. RESULTS: The cyst wall was composed of dense collagen fibers lacking an epithelial lining and contained many fine capillary- or venule-like vessels. Hemosiderin-laden macrophages were observed among the collagen fibers. Strong immunoreactivity for tPA was revealed in the endothelial cells of the vessels in the cyst wall. Chemical analysis of the cyst content revealed a marked delay in the activated partial thromboplastin time and prothrombin time, a low fibrinogen concentration, and high concentrations of the D-dimer and tPA-plasminogen activator inhibitor-1 complex. CONCLUSIONS: Our findings indicate that blood coagulation and hemostasis occur first and that fibrinolysis occurs second in hematic cysts. Gradual expansion of the cyst may be due to hyperfibrinolysis resulting from oversecretion of tPA from the endothelial cells in the cyst wall, thus impairing normal hemostasis. Hemorrhage may then recur, resulting in enlargement of the hematic cyst. These mechanisms are similar to those occurring in chronic subdural hematomas. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.