To investigate the exposure parameters for thoracic spine/(TS) radiography that allows the image acquisition at the lowest dose possible, while maintaining an adequate image quality/(IQ) to identify ...all relevant anatomical criteria.
An experimental phantom study was conducted, and 48 different radiographs of TS (24 AP/24 lateral) were acquired. The Automatic Exposure Control/(AEC) with the central sensor was used to select the beam intensity, while Source-to-Detector-Distance/(SDD) (AP:115/125 cm; Lateral:115/150 cm), tube potential (AP:70/81/90 kVp; Lateral: 81/90/102 kVp), use of grid/no grid and focal spot (fine/broad) were manipulated. IQ was assessed by observers with ViewDEX. Effective Dose (ED) was estimated using PCXMC2.0 software. Descriptive statistics paired with intraclass correlation coefficient (ICC) were applied to analyse data.
The ED increased with a greater SDD for lateral-view, presenting a significant difference (p = 0.038), however IQ was not affected. For both AP and lateral, the use of grid had a significant effect on ED (p < 0.001). Despite the images acquired without grid had lower IQ scores, the observers considered the IQ adequate for clinical use. A 20% reduction in ED (0.042mSv–0.033 mSv) was observed when increasing the beam energy from 70 to 90 kVp for AP grid in. The observers ICC ranged from moderate to good (0.5–0.75) in lateral and good to excellent (0.75–0.9) for AP views.
The optimised parameters in this context were 115 cm SDD, 90 kVp with grid for the best IQ and lowest ED. Further studies in clinical setting are necessary to enlarge the context and cover different body habitus and equipment.
The SDD impacts on dose for TS; Higher kVp and grid are necessary to better image quality.
While the systemic cardiovascular consequences of infrarenal aortic cross-clamping during aortic abdominal surgery are well documented, its repercussions on renal hemodynamics in humans have not been ...reported. In 12 patients, scheduled for elective aortic surgery, renal clearances, using 51Cr EDTA and 125I hippuran, were measured before, during, and after infrarenal aortic cross-clamping. A continuous infusion of mannitol 20% at a rate of 100 ml/h was administered throughout the study. Arterial and renal venous blood sampling, obtained at the midpoint of each period, permitted calculation of the extraction fraction of 125I hippuran and accurate determination of renal blood flow and its cortical-extracortical distribution. Although cardiac output and systemic vascular resistance did not change significantly between the three study periods, infrarenal aortic cross-clamping decreased 125I hippuran clearance by 29 +/- 15% (P less than 0.05) and renal blood flow by 38 +/- 14% (P less than 0.001). Simultaneously, an increase of 75 +/- 31% in renal vascular resistance (P less than 0.05) was observed and the extraction fraction of 125I hippuran increased from 0.67 +/- 0.05 to 0.74 +/- 0.05 (P less than 0.01). All of these changes, which indicate global diminution of renal perfusion with a redistribution of renal blood flow toward the cortical compartment, persisted for at least 1 h after release of the aortic clamp. Early signs of renal tubular damage, such as the appearance of lysozyme and ligandine in the urine, however, were never observed. The authors conclude that infrarenal aortic cross-clamping produces profound and sustained alterations in renal hemodynamics and may be harmful in patients with impaired renal function or when surgical occlusion of the aorta is prolonged.
We report a case of chronic debilitating BPF following right upper lobe resection. Despite several endobronchial applications of fibrin glue, we could not close it. Since the patient was extremely ...debilitated by symptoms due to the BPF, a thoracoplasty was attempted but was not successful. Finally, the BPF was definitely closed by instillation of talc into the pleura through thoracoscopy. To our knowledge, this is the first reported case of chemical closure of a recalcitrant BPF by the route of thoracoscopy. It also shows the failure of endoscopic fibrin glue application in such a condition.
Since many physical systems can be modeled by second order differential equation, airplane can also be thought of as an equivalent spring-mass-damper system. This makes the analysis of aircraft's ...damping and longitudinal static stability much simpler. For that matter, a model was proposed in which only pure pitching motion was considered and dependence of pitching moment on various factors was sought. A second order differential equation was then formulated in terms of stability derivatives in one variable only. From its characteristic equation, two roots can be obtained whose nature decide the stability of aircraft. The variation of different system parameters such as damping ratio, Z and natural frequency, ran as a function of various flight conditions such as flight velocity and altitude was also studied. Comparing these graphs with the pilot opinion contours, a judgment is passed about the flying qualities of aircraft at the specified conditions. If the aircraft is not safe and easy to handle, a substantial amount of damping should be added to it. Since the stability derivatives are a function of geometric and aerodynamic characteristics of the airplane, designer has some control over longitudinal dynamics by varying different structural parameters, if only that does not cause a subsequent loss in its flight performance. Hence, just by the virtue of second order differential equation, an optimum solution for the performance and handling of aircraft is estimated at different flight conditions.
In 1989, we reorganized acute and rehabilitation cares for patients operated for non small cell lung cancer (NSCLC) in order to decrease costs by setting up a specialised intermediate care unit ...(SICU). This report deals with the postoperative complications and the total cost of these cares (SICU, acute and rehabilitation cares) as well as their cost/benefit. From 1990 to 1994, we performed 95 thoracotomies, 7 exploratory and 88 with lung resection (24 pneumonectomies, 8 bilobectomies, 48 lobectomies and 8 segmentectomies or wedge resections). The postoperative staging was I in 52, II in 17, III a in 15, S III b in 2, IV in 2. Patients 30-days postoperative mortality was 2/95 (2.1%). We had in 11 patients respiratory complications (12%; 3 bronchopleural fistulas, 3 pneumonias, 3 pneumothorax > 7 days, 1 empyema, 1 chronic hypoxemia), in 15 patients cardiac arrhythmias which were easily controlled by medication and in 2 general complications (1 hemiplegia, 1 transitory stupor state). The total duration of hospital stay, including SICU, acute and rehabilitative cares, was 32 +/- 10 (3-70) days with a mean total cost of 14,722 Sfr. per case. In conclusion, surgery for NSCLC can be safely performed in intermediate cares without intensive care unit at low costs and with a low morbidity and mortality provided they are staffed by a specialised and well trained team.
