The Evans ratio for ventricular size: A calculation error

1979 ◽  
Vol 18 (2) ◽  
pp. 81-81 ◽  
Author(s):  
L. M. Zatz
Keyword(s):  
Calculation Error ◽  
Ventricular Size ◽  
Evans Ratio

Normal ventricular size in brain imaging does not exclude blockage of cerebrospinal fluid shunts

2006 ◽  
Vol 37 (03) ◽  
Author(s):  
S Parbel ◽  
S Vlaho ◽  
R Gerlach ◽  
L Porto ◽  
H Böhles ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Brain Imaging ◽  
Cerebrospinal Fluid Shunts ◽  
Ventricular Size

Muenke syndrome: long-term outcome of a syndrome-specific treatment protocol

2019 ◽  
Vol 24 (4) ◽  
pp. 415-422 ◽  
Author(s):  
Bianca K. den Ottelander ◽  
Robbin de Goederen ◽  
Marie-Lise C. van Veelen ◽  
Stephanie D. C. van de Beeten ◽  
Maarten H. Lequin ◽  
...  
Keyword(s):  
Treatment Protocol ◽  
First Year ◽  
Ventricular Size ◽  
Term Outcome ◽  
Long Term Outcome ◽  
Skull Growth ◽  
Muenke Syndrome ◽  
First Year Of Life

OBJECTIVEThe authors evaluated the long-term outcome of their treatment protocol for Muenke syndrome, which includes a single craniofacial procedure.METHODSThis was a prospective observational cohort study of Muenke syndrome patients who underwent surgery for craniosynostosis within the first year of life. Symptoms and determinants of intracranial hypertension were evaluated by longitudinal monitoring of the presence of papilledema (fundoscopy), obstructive sleep apnea (OSA; with polysomnography), cerebellar tonsillar herniation (MRI studies), ventricular size (MRI and CT studies), and skull growth (occipital frontal head circumference [OFC]). Other evaluated factors included hearing, speech, and ophthalmological outcomes.RESULTSThe study included 38 patients; 36 patients underwent fronto-supraorbital advancement. The median age at last follow-up was 13.2 years (range 1.3–24.4 years). Three patients had papilledema, which was related to ophthalmological disorders in 2 patients. Three patients had mild OSA. Three patients had a Chiari I malformation, and tonsillar descent < 5 mm was present in 6 patients. Tonsillar position was unrelated to papilledema, ventricular size, or restricted skull growth. Ten patients had ventriculomegaly, and the OFC growth curve deflected in 3 patients. Twenty-two patients had hearing loss. Refraction anomalies were diagnosed in 14/15 patients measured at ≥ 8 years of age.CONCLUSIONSPatients with Muenke syndrome treated with a single fronto-supraorbital advancement in their first year of life rarely develop signs of intracranial hypertension, in accordance with the very low prevalence of its causative factors (OSA, hydrocephalus, and restricted skull growth). This illustrates that there is no need for a routine second craniofacial procedure. Patient follow-up should focus on visual assessment and speech and hearing outcomes.

Reliability of the radiopharmaceutical shunt flow study for the detection of a CSF shunt malfunction in the presence of stable ventricular size

2020 ◽  
Vol 26 (4) ◽  
pp. 364-370
Author(s):  
Jeffrey J. Quezada ◽  
J. Gordon McComb
Keyword(s):  
Ct Scan ◽  
Operative Intervention ◽  
Shunt Malfunction ◽  
Shunt Revision ◽  
Csf Shunt ◽  
Technical Failure ◽  
Ventricular Size ◽  
Shunt Flow ◽  
Programmable Valve ◽  
Flow Study

OBJECTIVEThe authors sought to determine the reliability of a radiopharmaceutical (RP) shunt flow study for the detection of a CSF-diverting shunt malfunction in the presence of stable ventricular size.METHODSAfter the authors obtained IRB approval, all CSF RP shunt flow studies done between January 1, 2014, and January 1, 2019, in pediatric patients at Children’s Hospital Los Angeles were identified. Included in the study were only those patients in whom an MRI or CT scan was done during the hospital admission for shunt malfunction and showed no increase in ventricular size compared with the most recent prior MRI or CT scan when the patient was asymptomatic. Data recorded for analysis were patient age and sex, etiology of the hydrocephalus, shunt distal site, nonprogrammable versus programmable valve, operative findings if the shunt was revised, and follow-up findings for a minimum of 90 days after admission. The RP shunt flow study consisted of tapping the reservoir and injecting technetium-99m DTPA according to a set protocol.RESULTSThe authors identified 146 RP flow studies performed in 119 patients meeting the above criteria. Four of the 146 RP studies (3%) were nondiagnostic secondary to technical failure and were excluded from statistical analysis. Of the 112 normal flow studies, operative intervention was not undertaken in 102 (91%). The 10 (9%) remaining normal studies were performed in patients who underwent operative intervention, in which 8 patients had a proximal obstruction, 1 had a distal obstruction, and 1 patient had no obstruction. Of the 30 patients with abnormal flow studies, symptoms of shunt malfunction subsided in 9 (30%) patients and these patients did not undergo operative intervention. Of the 21 (70%) operated patients, obstruction was proximal in 9 patients and distal in 5, and for 7 patients the shunt tubing was either fractured or disconnected. Regression analysis indicated a significant association between the flow study interpretation and the odds for shunt revision (OR 27, 95% CI 10–75, p < 0.0001). No other clinical variables were significant. The sensitivity of a shunt flow study alone for detection of shunt malfunction in cases with stable ventricular size was the same as a shunt flow study plus an MRI or CT (70% vs 70%), but performing a shunt flow in addition to MRI or CT did increase the specificity from 92% to 100% and the accuracy from 87% to 94%.CONCLUSIONSRP shunt flow studies were of definite value in deciding whether to operatively intervene in patients with symptoms of shunt malfunction in whom no change in ventricular size was detected on current MRI or CT scans compared to scans obtained when the patients were asymptomatic.

scholarly journals Improvement Dependability of Offshore Horizontal-Axis Wind Turbines by Applying New Mathematical Methods for Calculation the Excess Speed in Case of Wind Gusts

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3085
Author(s):  
Konstantin Osintsev ◽  
Seregei Aliukov ◽  
Alexander Shishkov
Keyword(s):  
Computer Simulation ◽  
Wind Turbines ◽  
Experimental Studies ◽  
Offshore Wind ◽  
Approximation Schemes ◽  
Calculation Error ◽  
Strong Wind ◽  
Mathematical Methods ◽  
Wind Gusts ◽  
Gas Dynamic

The problem of increasing the reliability of wind turbines exists in the development of new offshore oil and natural gas fields. Reducing emergency situations is necessary due to the autonomous operation of drilling rigs and bulk seaports in the subarctic and Arctic climate. The relevance of the topic is linked with the development of a methodology for theoretical and practical studies of gas dynamics when gas flows in a pipe, based on a mathematical model using new mathematical methods for calculation of excess speeds in case of wind gusts. Problems in the operation of offshore wind turbines arise with storm gusts of wind, which is comparable to the wave movement of the gas flow. Thus, the scientific problem of increasing the reliability of wind turbines in conditions of strong wind gusts is solved. The authors indicate a gross error in the calculations when approximating through the use of the Fourier series. The obtained results will allow us to solve one of the essential problems of modeling at this stage of its development, namely: to reduce the calculation time and the adequacy of the model built for similar installations and devices. Experimental studies of gas-dynamic flows are carried out on the example of a physical model of a wind turbine. In addition, a computer simulation of the gas-dynamic flow process was carried out. The use of new approximation schemes in processing the results of experiments and computer simulation can reduce the calculation error by 1.2 percent.

scholarly journals Analysis of Tunnel Water Inrush Considering the Influence of Surrounding Rock Permeability Coefficient by Excavation Disturbance and Ground Stress

2021 ◽  
Vol 11 (8) ◽  
pp. 3645
Author(s):  
Helin Fu ◽  
Pengtao An ◽  
Long Chen ◽  
Guowen Cheng ◽  
Jie Li ◽  
...  
Keyword(s):  
Permeability Coefficient ◽  
Water Pressure ◽  
Water Inrush ◽  
Surrounding Rock ◽  
Water Inflow ◽  
Calculation Error ◽  
External Water Pressure ◽  
Ground Stress ◽  
External Water ◽  
Inflow Prediction

Affected by the coupling of excavation disturbance and ground stress, the heterogeneity of surrounding rock is very common. Presently, treating the permeability coefficient as a fixed value will reduce the prediction accuracy of the water inflow and the external water pressure of the structure, leading to distortion of the prediction results. Aiming at this problem, this paper calculates and analyzes tunnel water inflow when considering the heterogeneity of permeability coefficient of surrounding rock using a theoretical analysis method, and compares with field data, and verifies the rationality of the formula. The research shows that, when the influence of excavation disturbance and ground stress on the permeability coefficient of surrounding rock is ignored, the calculated value of the external water force of the tunnel structure is too small, and the durability and stability of the tunnel are reduced, which is detrimental to the safety of the structure. Considering the heterogeneity of surrounding rock, the calculation error of water inflow can be reduced from 27.3% to 13.2%, which improves the accuracy of water inflow prediction to a certain extent.

scholarly journals 107 RELATIONSHIP BETWEEN THE ANTERIOR MITRAL LEAFLET MOTION AND LEFT VENTRICULAR SIZE IN THE ECHOGRAM

1978 ◽  
Vol 12 ◽  
pp. 381-381
Author(s):  
Lily George ◽  
James W Mathewson ◽  
Thomos A Riemenschneider ◽  
Thomas J Barstow ◽  
Anthony N Demaia ◽  
...  
Keyword(s):  
Left Ventricular ◽  
Ventricular Size ◽  
Mitral Leaflet ◽  
Anterior Mitral Leaflet ◽  
Left Ventricular Size ◽  
Leaflet Motion

scholarly journals RIGHT VENTRICULAR SIZE MODIFIES THE EFFECT OF TRICUSPID REGURGITATION ON SURVIVAL IN OLDER AGED ADULTS

2021 ◽  
Vol 77 (18) ◽  
pp. 1702
Author(s):  
Jordan B. Strom ◽  
Ariane Fraiche ◽  
Jiaman Xu ◽  
Lawrence J. Markson ◽  
Connie Tsao ◽  
...  
Keyword(s):  
Right Ventricular ◽  
Tricuspid Regurgitation ◽  
Ventricular Size ◽  
Right Ventricular Size
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