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Sample records for preoperative duplex ultrasound

  1. Resolution of carotid stenosis pre-carotid intervention: A case for selective preoperative duplex ultrasound.

    Science.gov (United States)

    Ali, Abid; Ashrafi, Mohammed; Zeynali, Iraj

    2015-01-01

    Spontaneous resolution of carotid stenosis is a phenomenon that has been described in literature in the past. At present it is not routine practise to scan patients prior to carotid endarterectomy surgery within the UK. A 58 year old female presented to hospital with a history of sudden onset headache and left sided weakness. CT head showed findings in keeping with an acute right MCA territory infarct. A duplex ultrasound scan showed echolucent material in the right internal carotid artery forming a greater than 95% stenosis. The scan was unable to visualise the patency of the vessel distally due to the position of the mandible. The patient was provisionally listed for carotid endarterectomy. An MRA was requested prior to surgery to assess the patency of the distal internal carotid artery. The MRA of the carotids showed normal appearance of the common carotid, internal and vertebral arteries with no definite stenosis. A repeat duplex ultrasound confirmed there was no significant stenosis. The finding of complete resolution of stenosis on MRA was an unexpected event. Had the initial duplex imaging allowed visualisation of the distal vessel patency, our patient would have undergone unnecessary carotid surgery with the associated morbidity and mortality. This case report draws attention to the benefits of selective preoperative scanning, in sparing patients from unnecessary surgery as a result of finding occlusion or resolution of a previously diagnosed carotid stenosis. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  2. Role of routine pre-operative screening venous duplex ultrasound in morbidly obese patients undergoing bariatric surgery

    Directory of Open Access Journals (Sweden)

    P Praveen Raj

    2017-01-01

    Full Text Available Background/Aims: It is well established that obesity is a strongly associated risk factor for post-operative deep vein thrombosis (DVT. Physical effects and pro-thrombotic, pro-inflammatory and hypofibrinolytic effects of severe obesity may predispose to idiopathic DVT (pre-operatively because of which bariatric patients are routinely screened before surgery. The aim of this study was to audit the use of routine screening venous duplex ultrasound in morbidly obese patients before undergoing bariatric surgery. Methods: We retrospectively reviewed 180 patients who underwent bariatric surgery from August 2013 to August 2014 who had undergone pre-operative screening bilateral lower-extremity venous duplex ultrasound for DVT. Data were collected on patient's demographics, history of venous thromboembolism, prior surgeries and duplex ultrasound details of the status of the deep veins and superficial veins of the lower limbs. Results: No patients had symptoms or signs of DVT pre-operatively. No patient gave history of DVT. No patient was found to have iliac, femoral or popliteal vein thrombosis. Superficial venous disease was found in 17 (8%. One patient had a right lower limb venous ulcer. Conclusion: Thromboembolic problems in the morbidly obese before bariatric surgery are infrequent, and screening venous duplex ultrasound can be done in high-risk patients only.

  3. Primary chronic venous insufficiency of the lower extremities: preoperative color duplex Doppler ultrasound study

    International Nuclear Information System (INIS)

    Selfa, S.; Diago, T.; Ricart, M.; Chulia, R.; Martin, F.

    2000-01-01

    To asses the role of color duplex Doppler ultrasound (CDU) in the preoperative study of patients with varicose veins in lower extremities. We employed CDU to examine varicose veins in 342 lower limbs, assessing reflux in saphenous veins (SV), deep venous system (DVS) and perforating veins (PV). We analyzed the relationship between the anatomical extent of the reflux and the clinical findings. Insufficiency of the superficial venous system alone was uncommon, occurring in only 10.8% of the limbs examined. Reflux was observed in SV and PV in 48.2% of the legs. It was detected in all three systems in 29.2% of cases. The presence of reflux in more than one system and more than one value was associated with increased clinical severity. The site of venous reflux in lower extremities with varicose veins varies. Greater clinical severity is observed in the presence of more marked reflux in the DVS and PV. CDU provides anatomic and functional data on the three venous systems of the lower limbs, allowing an individualized therapeutic surgery. Preoperative localization of incompetent PV by means of CDU facilities their ligation. CDU is the technique of choice for the preoperative examination of the venous systems of patients with varicose veins. (Author)

  4. National variation in preoperative imaging, carotid duplex ultrasound criteria, and threshold for surgery for asymptomatic carotid artery stenosis.

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    Arous, Edward J; Simons, Jessica P; Flahive, Julie M; Beck, Adam W; Stone, David H; Hoel, Andrew W; Messina, Louis M; Schanzer, Andres

    2015-10-01

    Carotid endarterectomy (CEA) for asymptomatic carotid artery stenosis is among the most common procedures performed in the United States. However, consensus is lacking regarding optimal preoperative imaging, carotid duplex ultrasound criteria, and ultimately, the threshold for surgery. We sought to characterize national variation in preoperative imaging, carotid duplex ultrasound criteria, and threshold for surgery for asymptomatic CEA. The Society for Vascular Surgery Vascular Quality Initiative (VQI) database was used to identify all CEA procedures performed for asymptomatic carotid artery stenosis between 2003 and 2014. VQI currently captures 100% of CEA procedures performed at >300 centers by >2000 physicians nationwide. Three analyses were performed to quantify the variation in (1) preoperative imaging, (2) carotid duplex ultrasound criteria, and (3) threshold for surgery. Of 35,695 CEA procedures in 33,488 patients, the study cohort was limited to 19,610 CEA procedures (55%) performed for asymptomatic disease. The preoperative imaging modality used before CEA varied widely, with 57% of patients receiving a single preoperative imaging study (duplex ultrasound imaging, 46%; computed tomography angiography, 7.5%; magnetic resonance angiography, 2.0%; cerebral angiography, 1.3%) and 43% of patients receiving multiple preoperative imaging studies. Of the 16,452 asymptomatic patients (89%) who underwent preoperative duplex ultrasound imaging, there was significant variability between centers in the degree of stenosis (50%-69%, 70%-79%, 80%-99%) designated for a given peak systolic velocity, end diastolic velocity, and internal carotid artery-to-common carotid artery ratio. Although 68% of CEA procedures in asymptomatic patients were performed for an 80% to 99% stenosis, 26% were performed for a 70% to 79% stenosis, and 4.1% were performed for a 50% to 69% stenosis. At the surgeon level, the range in the percentage of CEA procedures performed for a duplex ultrasound

  5. Lower extremity revascularization without preoperative contrast arteriography: experience with duplex ultrasound arterial mapping in 485 cases.

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    Ascher, Enrico; Hingorani, Anil; Markevich, Natalia; Costa, Tatiana; Kallakuri, Shreedhar; Khanimoy, Yuri

    2002-01-01

    This study reviews our experience with duplex ultrasound arterial mapping (DUAM) for preoperative evaluation in 466 patients (262 men) who underwent 485 lower extremity revascularization procedures from January 1, 1998 to May 30, 2001. Preoperative imaging consisted of DUAM alone in 449 procedures and DUAM and contrast angiography (CA) in 36. An attempt to image from the distal aorta to the pedal arteries was made in all the patients. The selection of optimal inflow and outflow bypasses anastomotic sites was based on a schematic drawing following DUAM examination. Inflow disease was also assessed by intraoperative pressure gradient (IPG) between the distal anastomosis and radial arteries, and completion arteriography of the runoff vessels was obtained, which was correlated with the preoperative findings. Indications for surgery were severe claudication in 91 (19%) limbs, tissue loss in 197 (40%), rest pain in 113 (23%), acute ischemia in 46 (10%), popliteal aneurysm in 18 (4%), superficial femoral artery aneurysm in 1, abdominal aortic aneurysm with claudication in 1, and failing graft in 18 (4%). Age ranged from 30 to 97 years (mean 72 +/- 12 (SD) years) and risk factors such as diabetes, hypertension, use of tobacco, coronary artery disease, and end-stage renal disease were present in 45%, 45%, 44%, 44%, and 13% of the patients, respectively. One hundred twenty-one (25%) limbs had at least 1 previous ipsilateral revascularization. The mean DUAM time was 66 +/- 20 (SD) min (30-150 min). Additional preoperative imaging was deemed necessary in 36 cases due to extensive ulcers, edema, severe arterial wall calcification, and very poor runoff. The distal anastomosis was to the popliteal artery in 173 cases and to the tibial and pedal arteries in 255. Inflow procedures to the femoral arteries, embolectomy, thrombectomy, balloon angioplasty, and patch angioplasty accounted for the remaining 57 cases. Overall, 6-, 12-, and -24- month secondary patency rates were 86%, 80

  6. Clinical utility of carotid duplex ultrasound prior to cardiac surgery.

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    Lin, Judith C; Kabbani, Loay S; Peterson, Edward L; Masabni, Khalil; Morgan, Jeffrey A; Brooks, Sara; Wertella, Kathleen P; Paone, Gaetano

    2016-03-01

    Clinical utility and cost-effectiveness of carotid duplex examination prior to cardiac surgery have been questioned by the multidisciplinary committee creating the 2012 Appropriate Use Criteria for Peripheral Vascular Laboratory Testing. We report the clinical outcomes and postoperative neurologic symptoms in patients who underwent carotid duplex ultrasound prior to open heart surgery at a tertiary institution. Using the combined databases from our clinical vascular laboratory and the Society of Thoracic Surgery, a retrospective analysis of all patients who underwent carotid duplex ultrasound within 13 months prior to open heart surgery from March 2005 to March 2013 was performed. The outcomes between those who underwent carotid duplex scanning (group A) and those who did not (group B) were compared. Among 3233 patients in the cohort who underwent cardiac surgery, 515 (15.9%) patients underwent a carotid duplex ultrasound preoperatively, and 2718 patients did not (84.1%). Among the patients who underwent carotid screening vs no screening, there was no statistically significant difference in the risk factors of cerebrovascular disease (10.9% vs 12.7%; P = .26), prior stroke (8.2% vs 7.2%; P = .41), and prior transient ischemic attack (2.9% vs 3.3%; P = .24). For those undergoing isolated coronary artery bypass grafting (CABG), 306 (17.8%) of 1723 patients underwent preoperative carotid duplex ultrasound. Among patients who had carotid screening prior to CABG, the incidence of carotid disease was low: 249 (81.4%) had minimal or mild stenosis (duplex scanning and those who did not. Primary outcomes of patients who underwent open heart surgery also showed no difference in the perioperative mortality (5.1% vs 6.9%; P = .14) and stroke (2.6% vs 2.4%; P = .85) between patients undergoing preoperative duplex scanning and those who did not. Operative intervention of severe carotid stenosis prior to isolated CABG occurred in 2 of the 17 patients (11.8%) identified who

  7. Can duplex Doppler ultrasound replace computerized tomography in staging patients with renal cell carcinoma?

    NARCIS (Netherlands)

    Bos, SD; Mensink, HJA

    The purpose of this study was to evaluate the accuracy and reliability of duplex Doppler ultrasound (US) and computerized tomography (CT) in staging patients with renal cell carcinoma (RCC). Sixty-six patients were evaluated pre-operatively with duplex Doppler ultrasound and CT. The results were

  8. Duplex ultrasound for identifying renal artery stenosis

    DEFF Research Database (Denmark)

    Zachrisson, Karin; Herlitz, Hans; Lönn, Lars

    2017-01-01

    Background Renal artery duplex ultrasound (RADUS) is an established method for diagnosis of renal artery stenosis (RAS), but there is no consensus regarding optimal RADUS criteria. Purpose To define optimal cutoff values for RADUS parameters when screening for RAS using intra-arterial trans...

  9. Duplex ultrasound surveillance after carotid artery endarterectomy.

    Science.gov (United States)

    Al Shakarchi, Julien; Lowry, Danielle; Nath, Jay; Khawaja, Aurangzaib Z; Inston, Nicholas; Tiwari, Alok

    2016-06-01

    After carotid endarterectomy (CEA), patients have been regularly followed up by duplex ultrasound imaging. However, the evidence for long-term follow-up is not clear, especially if the results from an early duplex scan are normal. This study assessed and systematically reviewed the evidence base for long-term surveillance after CEA and a normal early scan. Electronic databases were searched for studies assessing duplex surveillance after CEA in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The primary outcome for this study was the incidence of restenosis after a normal early scan. The secondary outcome was the number of reinterventions after a normal early scan. The review included seven studies that reported 2317 procedures. Of those patients with a normal early scan, 2.8% (95% confidence interval, 0.7%-6%) developed a restenosis, and 0.4% (95% confidence interval, 0%-0.9%) underwent a reintervention for their restenosis during the follow-up period. This review confirms that routine postoperative duplex ultrasound surveillance after CEA is not necessary if the early duplex scan is normal. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  10. Renal duplex Doppler ultrasound findings in diabetics

    International Nuclear Information System (INIS)

    Shim, Hyang Yee; Kim, Young Geun; Kook, Cheol Keu; Yoon, Chong Hyun; Lee, Shin Hyung; Lee, Chang Joon

    1993-01-01

    The correlation between clinical-laboratory findings and renal duplex Doppler ultrasound findings was studied in 45 patients with diabetes mellitus to see the role of duplex Doppler ultrasound in the detection of diabetic nephropathy. The resistive indices in patients with elevated serum creatinine, BUN, proteinuria, and systolic blood pressure levels were statistically significantly higher than those in patients with normal levels (p<0.05). Also resistive indics in patients with retinopathy were higher than that in patients without retinopathy (p<0.05). But the ultrasound morphologic changes of kidney such as renal length, cortical eye-catching, and corticomedullarycontrast were not well correlated with clinical-laboratory data and resistive index. The resistive index of the kidney in conjunction with clinical-laboratory data in diabetics may be helpful in the evaluation of diabetic nephropathy

  11. Renal duplex Doppler ultrasound findings in diabetics

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    Shim, Hyang Yee; Kim, Young Geun; Kook, Cheol Keu; Yoon, Chong Hyun; Lee, Shin Hyung; Lee, Chang Joon [National Medical Center, Seoul (Korea, Republic of)

    1993-12-15

    The correlation between clinical-laboratory findings and renal duplex Doppler ultrasound findings was studied in 45 patients with diabetes mellitus to see the role of duplex Doppler ultrasound in the detection of diabetic nephropathy. The resistive indices in patients with elevated serum creatinine, BUN, proteinuria, and systolic blood pressure levels were statistically significantly higher than those in patients with normal levels (p<0.05). Also resistive indics in patients with retinopathy were higher than that in patients without retinopathy (p<0.05). But the ultrasound morphologic changes of kidney such as renal length, cortical eye-catching, and corticomedullarycontrast were not well correlated with clinical-laboratory data and resistive index. The resistive index of the kidney in conjunction with clinical-laboratory data in diabetics may be helpful in the evaluation of diabetic nephropathy

  12. Duplex ultrasound evidence of fat embolism syndrome

    Directory of Open Access Journals (Sweden)

    Abdallah Naddaf, MD

    2016-12-01

    Full Text Available Fat embolism syndrome is a potentially fatal disease process most commonly associated with long-bone and pelvic fractures. Reports describing ultrasound evidence of fat emboli are restricted to echocardiography. We propose a new objective finding on venous duplex ultrasound imaging of the lower extremities as a useful diagnostic criterion by presenting the case reports of two patients with acute long-bone fractures, possibly leading to earlier orthopedic fixation and allocation of resources to those patients at higher risk of fat embolism syndrome.

  13. Duplex ultrasound: Indications and findings in a newly created ...

    African Journals Online (AJOL)

    Duplex ultrasound: Indications and findings in a newly created facility at the University of Calabar Teaching Hospital, Calabar. ... It is recommended that timely referrals be made, and mobile Doppler units be acquired to save more lives and limbs in the developing world. Keywords: Calabar, deep venous thrombosis, duplex ...

  14. The value and economic analysis of routine postoperative carotid duplex ultrasound surveillance after carotid endarterectomy.

    Science.gov (United States)

    AbuRahma, Ali F; Srivastava, Mohit; AbuRahma, Zachary; Jackson, Will; Mousa, Albeir; Stone, Patrick A; Dean, L Scott; Green, Jason

    2015-08-01

    Several studies have reported on the role of postoperative duplex ultrasound surveillance after carotid endarterectomy (CEA) with varying results. Most of these studies had a small sample size or did not analyze cost-effectiveness. We analyzed 489 of 501 CEA patients with patch closure. All patients had immediate postoperative duplex ultrasound examination and were routinely followed up both clinically and with duplex ultrasound at regular intervals of 1 month, 6 months, 12 months, and every 12 months thereafter. A Kaplan-Meier analysis was used to estimate the rate of ≥50% and ≥80% post-CEA restenosis over time and the time frame of progression from normal to ≥50% or ≥80% restenosis. The cost of post-CEA duplex surveillance was also estimated. Overall, 489 patients with a mean age of 68.5 years were analyzed. Ten of these had residual postoperative ≥50% stenosis, and 37 did not undergo a second duplex ultrasound examination and therefore were not included in the final analysis. The mean follow-up was 20.4 months (range, 1-63 months), with a mean number of duplex ultrasound examinations of 3.6 (range, 1-7). Eleven of 397 patients (2.8%) with a normal finding on immediate postoperative duplex ultrasound vs 4 of 45 (8.9%) with mild stenosis on immediate postoperative duplex ultrasound progressed to ≥50% restenosis (P = .055). Overall, 15 patients (3.1%) had ≥50% restenosis, 9 with 50% to duplex ultrasound), which equals $1,408,320, to detect only four patients with ≥80% to 99% restenosis who may have been potential candidates for reintervention. This study shows that the value of routine postoperative duplex ultrasound surveillance after CEA with patch closure may be limited, particularly if the finding on immediate postoperative duplex ultrasound is normal or shows minimal disease. Copyright © 2015 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  15. Importance of diastolic velocities in the detection of celiac and mesenteric artery disease by duplex ultrasound

    DEFF Research Database (Denmark)

    Perko, M J; Just, S; Schroeder, T V

    1997-01-01

    To assess the predictive value of ultrasound duplex scanning in the detection of superior mesenteric artery (SMA) and celiac artery (CA) occlusive disease.......To assess the predictive value of ultrasound duplex scanning in the detection of superior mesenteric artery (SMA) and celiac artery (CA) occlusive disease....

  16. Assessing the effect of different operation techniques on postoperative duplex ultrasound quality after carotid endarterectomy.

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    Grambow, E; Heller, T; Wieneke, P; Weiß, C; Klar, E; Weinrich, M

    2018-01-01

    Duplex ultrasound is the first choice in diagnostics and surveillance of stenoses of the internal carotid arteries before and even after surgery. Therefore, the quality of duplex ultrasound is crucial to investigate these vascular pathologies. Aim of this study was the evaluation whether different surgical techniques affect the postoperative quality of duplex ultrasound. In a time period from January to May 2015 duplex ultrasound of the cervical vessels was performed in 75 patients after unilateral endarterectomy of the internal carotid artery at our department between 2006 and 2012. Thereby, the non-operated contralateral side served as a control. Study groups were defined by the surgical techniques of eversion- or thrombendarterectomy with patch plasty using different patch materials and/or a haemostatic sealant. Duplex ultrasound analysis included acoustic impedance, extinction of ultrasound, thickness of skin and individual anatomic aspects of the patients. Carotid endarterectomy itself reduced intravascular grey levels, skin thickness and increased extinction of duplex ultrasound when compared to the non-operated side of the neck. In contrast, neither the kind of chosen operative technique nor the use of different patch materials or the application of a haemostatic sealant showed an effect in this regards. Whereas carotid endarterectomy per se worsens the quality of postoperative duplex ultrasound, the different analysed surgical techniques as well as used patches and the application of a haemostatic sealant can be assumed to be equal regarding the quality of postoperative ultrasound.

  17. Preoperative Duplex Scanning is a Helpful Diagnostic Tool in Neurogenic Thoracic Outlet Syndrome.

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    Orlando, Megan S; Likes, Kendall C; Mirza, Serene; Cao, Yue; Cohen, Anne; Lum, Ying Wei; Freischlag, Julie A

    2016-01-01

    To evaluate the diagnostic role of venous and arterial duplex scanning in neurogenic thoracic outlet syndrome (NTOS). Retrospective review of patients who underwent duplex ultrasonography prior to first rib resection and scalenectomy (FRRS) for NTOS from 2005 to 2013. Abnormal scans included ipsilateral compression (IC) with abduction of the symptomatic extremity (>50% change in subclavian vessel flow), contralateral (asymptomatic side) compression (CC) or bilateral compression (BC). A total of 143 patients (76% female, average age 34, range 13-59) underwent bilateral preoperative duplex scanning. Ipsilateral compression was seen in 44 (31%), CC in 12 (8%), and BC in 14 (10%). Seventy-three (51%) patients demonstrated no compression. Patients with IC more often experienced intraoperative pneumothoraces (49% vs. 25%, P duplex ultrasonography can assist in NTOS diagnosis. Ipsilateral compression on abduction often correlates with Adson testing. © The Author(s) 2016.

  18. Multicenter assessment of venous reflux by duplex ultrasound.

    Science.gov (United States)

    Lurie, Fedor; Comerota, Anthony; Eklof, Bo; Kistner, Robert L; Labropoulos, Nicos; Lohr, Joann; Marston, William; Meissner, Mark; Moneta, Gregory; Neglén, Peter; Neuhardt, Diana; Padberg, Frank; Welsh, Harold J

    2012-02-01

    This prospective multicenter investigation was conducted to define the repeatability of duplex-based identification of venous reflux and the relative effect of key parameters on the reproducibility of the test. Repeatability was studied by having the same technologist perform duplicate tests, at the same time of the day, using the same reflux-provoking maneuver and with the patient in the same position. Reproducibility was examined by having two different technologists perform the test at the same time of the day, using the same reflux-provoking maneuver and with the patient in the same position. Facilitated reproducibility was studied by having two different technologists examine the same patients immediately after an educational intervention. Limits of agreement between two duplex scans were studied by changing three elements of the test: time of the day (morning vs afternoon), patient's position (standing vs supine), and reflux initiation (manual vs automatic compression-decompression). The study enrolled 17 healthy volunteers and 57 patients with primary chronic venous disease. Repeatability of reflux time measurements in deep veins did not significantly differ with the time of day, the patient's position, or the reflux-provoking maneuver. Reflux measurements in the superficial veins were more repeatable (P ultrasound detection of venous reflux. Reports should include information on the time of the test, the patient's position, and the provoking maneuver used. Adopting a uniform cut point of 0.5 second for pathologic reflux can significantly improve the reliability of reflux detection. Implementation of a standard protocol should elevate the minimal standard for agreement between repeated tests from the current 70% to at least 80% and with more rigid standardization, to 90%. Copyright © 2012 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

  19. Diagnosing erectile dysfunction: the penile dynamic colour duplex ultrasound revisited.

    Science.gov (United States)

    Aversa, A; Bruzziches, R; Spera, G

    2005-12-01

    A number of disease processes of the penis including Peyronie's disease, priapism, penile fractures and tumors are clearly visualized with ultrasound. Diagnostic evaluation of erectile dysfunction (ED) by penile dynamic colour-duplex Doppler ultrasonography (D-CDDU) is actually considered a second level approach to ED patients because of the fact that intracavernous injections test IV with prostaglandin-E(1) may provide important information about the patients' erectile capacity. However, no direct vascular imaging and a high percentage of false negative diagnoses of vasculogenic ED are its major pitfalls and subsequent treatment decisions remain quite limited. The occurrence of ED and its sentinel relationship to cardiovascular disease has prompted more accurate vascular screening in all patients even in the absence of cardiovascular risk factors. The sonographic evaluation of the intima-media thickness of the carotid arteries may sometimes represent an early manifestation of diffuse atherosclerotic disease and endothelial damage. This latter finding is often the cause of failure to oral agents, i.e. phosphodiesterase inhibitors, because of inability of the dysfunctional endothelium to release nitric oxide. D-CDDU represents an accurate tool to investigate cavernous artery inflow and venous leakage when compared with more invasive diagnostic techniques i.e. selective arteriography and dynamic infusion cavernosometry along with cavernosography.

  20. Validation of a novel duplex ultrasound objective structured assessment of technical skills (DUOSATS) for arterial stenosis detection.

    Science.gov (United States)

    Jaffer, U; Singh, P; Pandey, V A; Aslam, M; Standfield, N J

    2014-01-01

    Duplex ultrasound facilitates bedside diagnosis and hence timely patient care. Its uptake has been hampered by training and accreditation issues. We have developed an assessment tool for Duplex arterial stenosis measurement for both simulator and patient based training. A novel assessment tool: duplex ultrasound assessment of technical skills was developed. A modified duplex ultrasound assessment of technical skills was used for simulator training. Novice, intermediate experience and expert users of duplex ultrasound were invited to participate. Participants viewed an instructional video and were allowed ample time to familiarize with the equipment. Participants' attempts were recorded and independently assessed by four experts using the modified duplex ultrasound assessment of technical skills. 'Global' assessment was also done on a four point Likert scale. Content, construct and concurrent validity as well as reliability were evaluated. Content and construct validity as well as reliability were demonstrated. The simulator had good satisfaction rating from participants: median 4; range 3-5. Receiver operator characteristic analysis has established a cut point of 22/ 34 and 25/ 40 were most appropriate for simulator and patient based assessment respectively. We have validated a novel assessment tool for duplex arterial stenosis detection. Further work is underway to establish transference validity of simulator training to improved skill in scanning patients. We have developed and validated duplex ultrasound assessment of technical skills for simulator training.

  1. Preoperative diagnosis of Amyand's hernia by ultrasound and computed tomography

    Directory of Open Access Journals (Sweden)

    Husam Vehbi

    2016-06-01

    Full Text Available Inguinal hernia is the most common seen groin hernias which mostly contain bowel. The incidence of vermiform appendix in an inguinal hernia is seen in 1% of all inguinal hernia. This is known as Amyand's hernia. Appendix within a hernia can be normal or complicated by appendicitis. Most of these cases are not diagnosed preoperatively and managed during surgery. Preoperative diagnosis of these cases is so rare. Very few cases have been reported so far.In our case, we diagnosed an inflamed appendix in a 49 years old female within right inguinal hernia by using ultrasound and confirmed it by CT scan. Keywords: Amyand's hernia, Appendicitis

  2. Development of a Duplex Ultrasound Simulator and Preliminary Validation of Velocity Measurements in Carotid Artery Models.

    Science.gov (United States)

    Zierler, R Eugene; Leotta, Daniel F; Sansom, Kurt; Aliseda, Alberto; Anderson, Mark D; Sheehan, Florence H

    2016-07-01

    Duplex ultrasound scanning with B-mode imaging and both color Doppler and Doppler spectral waveforms is relied upon for diagnosis of vascular pathology and selection of patients for further evaluation and treatment. In most duplex ultrasound applications, classification of disease severity is based primarily on alterations in blood flow velocities, particularly the peak systolic velocity (PSV) obtained from Doppler spectral waveforms. We developed a duplex ultrasound simulator for training and assessment of scanning skills. Duplex ultrasound cases were prepared from 2-dimensional (2D) images of normal and stenotic carotid arteries by reconstructing the common carotid, internal carotid, and external carotid arteries in 3 dimensions and computationally simulating blood flow velocity fields within the lumen. The simulator displays a 2D B-mode image corresponding to transducer position on a mannequin, overlaid by color coding of velocity data. A spectral waveform is generated according to examiner-defined settings (depth and size of the Doppler sample volume, beam steering, Doppler beam angle, and pulse repetition frequency or scale). The accuracy of the simulator was assessed by comparing the PSV measured from the spectral waveforms with the true PSV which was derived from the computational flow model based on the size and location of the sample volume within the artery. Three expert examiners made a total of 36 carotid artery PSV measurements based on the simulated cases. The PSV measured by the examiners deviated from true PSV by 8% ± 5% (N = 36). The deviation in PSV did not differ significantly between artery segments, normal and stenotic arteries, or examiners. To our knowledge, this is the first simulation of duplex ultrasound that can create and display real-time color Doppler images and Doppler spectral waveforms. The results demonstrate that an examiner can measure PSV from the spectral waveforms using the settings on the simulator with a mean absolute error

  3. Gallblader varices in children with portal cavernoma: duplex-Doppler and color Doppler ultrasound studies

    International Nuclear Information System (INIS)

    Muro, D.; Sanguesa, C.; Lopez, A.

    1998-01-01

    To determine the prevalence of varices in the gallbladder wall, observed by duplex-Doppler and color Doppler ultrasound, in children with cavernoma of the portal vein. Nineteen patients with portal hypertension were studied prospectively by duplex-Doppler and color Doppler ultrasound: 12 of the patients had developed a cavernoma of the portal vein. The presence of peri vesicular varices was assessed in the group of patients with portal cavernoma. Duplex-Doppler and color Doppler ultrasound disclosed the presence of varices in gallbladder wall in nine of the 12 patients (75%). The varices appeared as anechoic and serpiginous areas, and Doppler ultrasound revealed slowed venous flow. However, the three patients in whom gallbldder varices were not detected presented collateral gastric ciculation and spontaneous splenorenal shunt. Gallbladder varices are common in children with portal vein cavernoma; they present hepatopetal flow. Their developments is not related to the size of the portal cavernoma, the presence of spontaneous portosystemic shunts, or endoscopic obliteration of gastric and esophageal varices. The detection of gallbladder varices in patients with portal hypertension who are to undergo biliary surgery is highly important for the surgeon, helping to avoid perioperative complications. (Author) 15 refs

  4. Endoscopic ultrasound duplex scanning for measurement of portal venous flow. Validation against transit time ultrasound flowmetry in pigs

    DEFF Research Database (Denmark)

    Hansen, E F; Strandberg, C; Bendtsen, F

    1999-01-01

    with that of transit time ultrasound (TTU) in healthy pigs. The ability of EUS to detect changes in the portal venous flow after pharmacologic intervention was also investigated. METHODS: Six anaesthetized pigs were studied. Portal venous flow was measured simultaneously by EUS duplex scanning, using a Pentax FG-32UA...... echoendoscope connected to a Hitachi EUB 515-A ultrasound scanner, and by TTU with a Cardiomed CM 4000 flowmeter probe placed on the portal vein. Terlipressin, 1 mg, and placebo were administered in a blind, randomized, crossover design. Measurements were taken at base line and 30 min after each drug...

  5. Pre-operative Duplex Ultrasonography in Arteriovenous Fistula Creation: Intra- and Inter-observer Agreement.

    Science.gov (United States)

    Zonnebeld, Niek; Maas, Tommy M G; Huberts, Wouter; van Loon, Magda M; Delhaas, Tammo; Tordoir, Jan H M

    2017-11-01

    Although clinical guidelines on arteriovenous fistula (AVF) creation advocate minimum luminal arterial and venous diameters, assessed by duplex ultrasonography (DUS), the clinical value of routine DUS examination is under debate. DUS might be an insufficiently repeatable and/or reproducible imaging modality because of its operator dependency. The present study aimed to assess intra- and inter-observer agreement of DUS examination in support of AVF surgery planning. Ten end stage renal disease patients were included, to assess intra- and inter-observer agreement of pre-operative DUS measurements. All measurements were performed by two trained and experienced vascular technicians, blinded to measurement readings. From the routine DUS protocol, representative measurements (venous diameters, and arterial diameters and volume flow in the upper arm and forearm) were selected. For intra-observer agreement the measurements were performed in triplicate, with the probe released from the skin between each. Intraclass correlation coefficients were calculated for intra- and inter-observer agreement, and Bland-Altman plots used to graphically display mean measurement differences and limits of agreement. Ten patients (6 male, 59.4±19.7 years) consented to participate, and all predefined measurements were obtained. Intraclass correlation coefficients for intra-observer agreement of diameter measurements were at least 0.90 (95% CI 0.74-0.97; radial artery). Inter-observer agreement was at least 0.83 (0.46-0.96; lateral diameter upper arm cephalic vein). The Bland-Altman plots showed acceptable mean measurement differences and limits of agreement. In experienced hands, excellent intra- and inter-observer agreement can be reached for the discrete pre-operative DUS measurements advocated in clinical guidelines. DUS is therefore a reliable imaging modality to support AVF surgery planning. The content of DUS protocols, however, needs further standardisation. Copyright © 2017 European

  6. Estimation of brachial artery volume flow by duplex ultrasound imaging predicts dialysis access maturation.

    Science.gov (United States)

    Ko, Sae Hee; Bandyk, Dennis F; Hodgkiss-Harlow, Kelley D; Barleben, Andrew; Lane, John

    2015-06-01

    This study validated duplex ultrasound measurement of brachial artery volume flow (VF) as predictor of dialysis access flow maturation and successful hemodialysis. Duplex ultrasound was used to image upper extremity dialysis access anatomy and estimate access VF within 1 to 2 weeks of the procedure. Correlation of brachial artery VF with dialysis access conduit VF was performed using a standardized duplex testing protocol in 75 patients. The hemodynamic data were used to develop brachial artery flow velocity criteria (peak systolic velocity and end-diastolic velocity) predictive of three VF categories: low (800 mL/min). Brachial artery VF was then measured in 148 patients after a primary (n = 86) or revised (n = 62) upper extremity dialysis access procedure, and the VF category correlated with access maturation or need for revision before hemodialysis usage. Access maturation was conferred when brachial artery VF was >600 mL/min and conduit imaging indicated successful cannulation based on anatomic criteria of conduit diameter >5 mm and skin depth 800 mL/min was predicted when the brachial artery lumen diameter was >4.5 mm, peak systolic velocity was >150 cm/s, and the diastolic-to-systolic velocity ratio was >0.4. Brachial artery velocity spectra indicating VF 800 mL/min. Duplex testing to estimate brachial artery VF and assess the conduit for ease of cannulation can be performed in 5 minutes during the initial postoperative vascular clinic evaluation. Estimation of brachial artery VF using the duplex ultrasound, termed the "Fast, 5-min Dialysis Duplex Scan," facilitates patient evaluation after new or revised upper extremity dialysis access procedures. Brachial artery VF correlates with access VF measurements and has the advantage of being easier to perform and applicable for forearm and also arm dialysis access. When brachial artery velocity spectra criteria confirm a VF >800 mL/min, flow maturation and successful hemodialysis are predicted if anatomic criteria

  7. Hepatic venous pressure gradients measured by duplex ultrasound

    International Nuclear Information System (INIS)

    Tasu, J.-P.; Rocher, L.; Peletier, G.; Kuoch, V.; Kulh, E.; Miquel, A.; Buffet, C.; Biery, M.

    2002-01-01

    AIMS: The hepatic venous pressure gradient is a major prognostic factor in portal hypertension but its measurement is complex and requires invasive angiography. This study investigated the relationship between the hepatic venous pressure gradient and a number of Doppler measurements, including the arterial acceleration index. METHOD: We measured the hepatic venous pressure gradient in 50 fasting patients at hepatic venography. Immediately afterwards, a duplex sonographic examination of the liver was performed at which multiple measurements and indices of the venous and arterial hepatic vasculature were made. RESULTS: Hepatic arterial acceleration was correlated directly with the hepatic venous pressure gradient (r = 0.83, P -2 provided a positive predictive value of 95%, a sensitivity of 65% and a specificity of 95% for detecting patients with severe portal hypertension (hepatic venous pressure gradient > 12 mmHg). A correlation between the hepatic venous pressure gradient and the congestion index of the portal vein velocity (r = 0.45,P = 0.01) and portal vein velocity (r = 0.40,P = 0.044), was also noted. CONCLUSION: Measuring the hepatic arterial acceleration index may help in the non-invasive evaluation of portal hypertension. Tasu, J.-P. et al. (2002)

  8. Hepatic venous pressure gradients measured by duplex ultrasound

    Energy Technology Data Exchange (ETDEWEB)

    Tasu, J.-P.; Rocher, L.; Peletier, G.; Kuoch, V.; Kulh, E.; Miquel, A.; Buffet, C.; Biery, M

    2002-08-01

    AIMS: The hepatic venous pressure gradient is a major prognostic factor in portal hypertension but its measurement is complex and requires invasive angiography. This study investigated the relationship between the hepatic venous pressure gradient and a number of Doppler measurements, including the arterial acceleration index. METHOD: We measured the hepatic venous pressure gradient in 50 fasting patients at hepatic venography. Immediately afterwards, a duplex sonographic examination of the liver was performed at which multiple measurements and indices of the venous and arterial hepatic vasculature were made. RESULTS: Hepatic arterial acceleration was correlated directly with the hepatic venous pressure gradient (r = 0.83, P < 0.0001) and with the Child-Pugh score (r = 0.63, P < 0.0001). An acceleration index cut-off value of 1 m.s{sup -2} provided a positive predictive value of 95%, a sensitivity of 65% and a specificity of 95% for detecting patients with severe portal hypertension (hepatic venous pressure gradient > 12 mmHg). A correlation between the hepatic venous pressure gradient and the congestion index of the portal vein velocity (r = 0.45,P = 0.01) and portal vein velocity (r = 0.40,P = 0.044), was also noted. CONCLUSION: Measuring the hepatic arterial acceleration index may help in the non-invasive evaluation of portal hypertension. Tasu, J.-P. et al. (2002)

  9. Duplex ultrasound and computed tomography angiography in the follow-up of endovascular abdominal aortic aneurysm repair: a comparative study

    International Nuclear Information System (INIS)

    Cantador, Alex Aparecido; Siqueira, Daniel Emilio Dalledone; Jacobsen, Octavio Barcellos; Baracat, Jamal; Pereira, Ines Minniti Rodrigues; Menezes, Fabio Hüsemann; Guillaumon, Ana Terezinha

    2016-01-01

    Objective: To compare duplex ultrasound and computed tomography (CT) angiography in terms of their performance in detecting endoleaks, as well as in determining the diameter of the aneurysm sac, in the postoperative follow-up of endovascular abdominal aortic aneurysm repair. Materials and Methods: This was a prospective study involving 30 patients who had undergone endovascular repair of infrarenal aortoiliac aneurysms. Duplex ultrasound and CT angiography were performed simultaneously by independent radiologists. Measurements of the aneurysm sac diameter were assessed, and the presence or absence of endoleaks was determined. Results: The average diameter of the aneurysm sac, as determined by duplex ultrasound and CT angiography was 6.09 ± 1.95 and 6.27 ± 2.16 cm, respectively. Pearson's correlation coefficient showing a statistically significant correlation (R = 0.88; p < 0.01). Comparing the duplex ultrasound and CT angiography results regarding the detection of endoleaks, we found that the former had a negative predictive value of 92.59% and a specificity of 96.15%. Conclusion: Our results show that there is little variation between the two methods evaluated, and that the choice between the two would have no significant effect on clinical management. Duplex ultrasound could replace CT angiography in the postoperative follow-up of endovascular aneurysm repair of the infrarenal aorta, because it is a low-cost procedure without the potential clinical complications related to the use of iodinated contrast and exposure to radiation. (author)

  10. Duplex ultrasound and computed tomography angiography in the follow-up of endovascular abdominal aortic aneurysm repair: a comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Cantador, Alex Aparecido; Siqueira, Daniel Emilio Dalledone; Jacobsen, Octavio Barcellos; Baracat, Jamal; Pereira, Ines Minniti Rodrigues; Menezes, Fabio Hüsemann; Guillaumon, Ana Terezinha, E-mail: alex_cantador@yahoo.com.br [Universidade Estadual de Campinas (FCM/UNICAMP), Campinas, SP (Brazil). Faculdade de Ciencias Medicas

    2016-07-15

    Objective: To compare duplex ultrasound and computed tomography (CT) angiography in terms of their performance in detecting endoleaks, as well as in determining the diameter of the aneurysm sac, in the postoperative follow-up of endovascular abdominal aortic aneurysm repair. Materials and Methods: This was a prospective study involving 30 patients who had undergone endovascular repair of infrarenal aortoiliac aneurysms. Duplex ultrasound and CT angiography were performed simultaneously by independent radiologists. Measurements of the aneurysm sac diameter were assessed, and the presence or absence of endoleaks was determined. Results: The average diameter of the aneurysm sac, as determined by duplex ultrasound and CT angiography was 6.09 ± 1.95 and 6.27 ± 2.16 cm, respectively. Pearson's correlation coefficient showing a statistically significant correlation (R = 0.88; p < 0.01). Comparing the duplex ultrasound and CT angiography results regarding the detection of endoleaks, we found that the former had a negative predictive value of 92.59% and a specificity of 96.15%. Conclusion: Our results show that there is little variation between the two methods evaluated, and that the choice between the two would have no significant effect on clinical management. Duplex ultrasound could replace CT angiography in the postoperative follow-up of endovascular aneurysm repair of the infrarenal aorta, because it is a low-cost procedure without the potential clinical complications related to the use of iodinated contrast and exposure to radiation. (author)

  11. Early evaluation of renal hemodynamic alterations in type I diabetes mellitus with duplex ultrasound

    Directory of Open Access Journals (Sweden)

    Saif Aasem

    2010-01-01

    Full Text Available To evaluate the role of renal duplex ultrasonography in the detection of early alte-ration of renal blood flow in type I diabetic patients, we studied with duplex ultrasound 32 patients with type I diabetes mellitus (19 males, 13 females, age range 8-19 years and 35 age and sex-matched controls. The resistivity indices (RIs and pulsatility indices (PIs of the main renal as well as intra-renal arteries were calculated. Compared with the healthy control subjects, diabetic patients had significantly higher resistivity indices (RIs in the intrarenal (segmental, arcuate and interlobar ar-teries (P= 0.001. The study, also revealed a significantly positive correlation between the RIs in the intrarenal arteries in diabetics and the albumin/creatinine ratio (r= 0.54, 0.52 and 0.51 respectively, glycated hemoglobin (r= 0.61, 0.59 and 0.63 respectively, as well as the estimated GFR (e-GFR (r= 0.53, 0.51 and 0.57 respectively. We conclude that the current study documented early intra-renal hemodynamic alterations in the form of pathologically elevated intrarenal RIs. This denotes the potential usefulness of duplex evaluation of the intrarenal arteries, as a noninvasive procedure, for monitoring type 1 diabetic patients to predict those at risk of diabetic nephropathy.

  12. Non-thrombotic Abnormalities on Lower Extremity Venous Duplex Ultrasound Examinations

    Directory of Open Access Journals (Sweden)

    Adhikari, Srikar

    2015-03-01

    Full Text Available Introduction: Emergency physician-performed compression ultrasonography focuses primarily on the evaluation of the proximal veins of the lower extremity in patients with suspected deep venous thrombosis (DVT. A detailed sonographic evaluation of lower extremity is not performed. The objective of this study was to determine the prevalence of non-thrombotic findings on comprehensive lower extremity venous duplex ultrasound (US examinations performed on emergency department (ED patients. Methods: We performed a retrospective six-year review of an academic ED’s records of adult patients who underwent a comprehensive lower extremity duplex venous US examination for the evaluation of DVT. The entire US report was thoroughly reviewed for non-thrombotic findings. Results: We detected non-thrombotic findings in 263 (11%, 95% CI [9.5-11.9%] patients. Among the non-thrombotic findings, venous valvular incompetence (81, 30% was the most frequent, followed by cyst/mass (41, 15%, lymphadenopathy (33, 12%, phlebitis (12, 4.5%, hematoma (8, 3%, cellulitis (1, 0.3% and other (6, 2.2%. Conclusion: In our study, we detected a variety of non-thrombotic abnormalities on comprehensive lower extremity venous duplex US examinations performed on ED patients. Some of these abnormalities could be clinically significant and potentially be detected with point-of-care lower extremity US examinations if the symptomatic region is evaluated. In addition to assessment of the proximal veins for DVT, we recommend sonographic evaluation of the symptomatic area in the lower extremity when performing point-of-care ultrasound examinations to identify non-thrombotic abnormalities that may require immediate intervention or close follow up. [West J Emerg Med. 2015;16(2:250–254.

  13. [Can TOF MRA replace duplex and Doppler sonography in preoperative assessment of the carotid arteries? A prospective comparison and review of the literature].

    Science.gov (United States)

    Krappel, F A; Bauer, E; Harland, U

    2002-01-01

    To examine the quality and usefulness of time-of-flight MR-angiography and duplex-doppler sonography, respectively, in assessment of the extracranial arteries before cervical spine operations. Patients scheduled for operations of the cervical spine had an MRI plus TOF as well as a duplex and Doppler scan. At the time of the examination the radiologist and the neurologist in charge were blinded for the study. Endpoints were not only the accuracy of the procedures but more so which method improved the preoperative process most. Twenty patients were examined so far. Only in one case did the result differ when a complete occlusion diagnosed sonographically was judged as a severe stenosis on MRA. One patient did not tolerate the MRA for the extra 5 minutes necessary, therefore a contrast-enhanced MRA was performed. MRA eased the preoperative process as imaging of the pathology and the carotids were realised in one step. The costs were slightly higher for MRA than for duplex-doppler sonography. TOF-MRA can replace the duplex-doppler examination in the preoperative assessment of the carotids and has the potential to streamline the preoperative time schedule. Similar to duplex and doppler, in order to be accurate enough the method requires a high degree of expertise from the radiologist.

  14. Role of Duplex Power Doppler Ultrasound in Differentiation between Malignant and Benign Thyroid Nodules

    International Nuclear Information System (INIS)

    Algin, Oktay; Algin, Efnan; Gokalp, Gokhan; Ocakog, Gokhan; Erdog an, Cuneyt; Saraydaroglu, Ozlem; Ercan Tuncel, Prof

    2010-01-01

    To evaluate the usage of duplex power Doppler ultrasound (PDUS) for the differentiation of benign and malignant thyroid nodules. We prospectively examined 77 thyroid nodules in 60 patients undergoing ultrasound-guided fine needle aspiration biopsy (FNAB). Each nodule was described according to size, inner structure, borders, parenchymal echogenicity, peripheral halo formation, and the presence of calcification (Bmode ultrasound findings). Vascularity as determined by PDUS imaging was defined as non-vascular, peripheral, central, or of mixed type. For each nodule, the pulsatility index (PI) and resistive index (RI) values were obtained. Results of FNAB and surgical pathological examination (if available) were used as a proof of final diagnosis to categorize all nodules as benign or malignant. A receiver operating characteristic (ROC) curve analysis was performed to establish cut-off, sensitivity, and specificity values associated with RI-PI values. A significant relationship was observed between malignancy and irregular margins, microcalcifications, and hypoechogenicity on ultrasound examination (p 0.05). The central, peripheral, and mean RI-PI values were higher in malignant nodules when compared to the other cytologies (p < 0.05). Vascularity is not a useful parameter for distinguishing malignant from benign thyroid nodules. However, RI and PI values are useful in distinguishing malignant from benign thyroid nodules

  15. Value of Duplex Ultrasound Assistance for Thromboaspiration and Dilation of Thrombosed Native Arterio-Venous Fistulae

    International Nuclear Information System (INIS)

    García-Medina, J.

    2013-01-01

    Purpose: To evaluate the value of duplex ultrasound assistance during thromboaspiration of thrombosed arteriovenous fistulae for haemodialysis. Materials and Methods: We prospectively studied 54 thrombosed native fistulae (23 with total thrombosis and 31 with partial thrombosis), in which we performed manual thromboaspiration guided by ultrasonography associated with fluoroscopy. Results: The fistulae were located in the forearm (n = 39) or in the upper arm (n = 15) of 46 patients. Mean patient age was 65 years, and hypertension was the most common risk factor (74 %). Mean access age was 928 days (range 69–2,290), and most fistulae were on the left side (41 cases, 75.92 %). The success rate was 83 % in the total thrombosis group and 100 % in the partial thrombosis group. Including initial failures, the respective primary patency rates in the total thrombosis group and the partial thrombosis group were, respectively, 83 ± 8 % (n = 20) and 87 ± 6 % (n = 28) at 1 month, 39 ± 10 % (n = 10) and 61 ± 8 % (n = 20) at 6 months, and 17 ± 8 % (n = 5) and 26 ± 8 % (n = 9) at 1 year. The mean decrease of fluoroscopy time with ultrasound was 3 min (range 1–5). The mean decrease of radiation dose was 2.6 Gy cm² (range 0.9–4.3]. Conclusion: Ultrasound is a feasible and useful tool in the management of thrombosed native fistulae, thus decreasing radiation exposure, and has no detrimental effect on success rates

  16. Validation of a novel venous duplex ultrasound objective structured assessment of technical skills for the assessment of venous reflux.

    Science.gov (United States)

    Jaffer, Usman; Normahani, Pasha; Lackenby, Kimberly; Aslam, Mohammed; Standfield, Nigel J

    2015-01-01

    Duplex ultrasound measurement of reflux time is central to the diagnosis of venous incompetence. We have developed an assessment tool for Duplex measurement of venous reflux for both simulator and patient-based training. A novel assessment tool, Venous Duplex Ultrasound Assessment of Technical Skills (V-DUOSATS), was developed. A modified DUOSATS was used for simulator training. Participants of varying skill level were invited to viewed an instructional video and were allowed ample time to familiarize with the Duplex equipment. Attempts made by the participants were recorded and independently assessed by 3 expert assessors and 5 novice assessors using the modified V-DUOSATS. "Global" assessment was also done by expert assessors on a 4-point Likert scale. Content, construct, and concurrent validities as well as reliability were evaluated. Content and construct validity as well as reliability were demonstrated. Receiver operator characteristic analysis-established cut points of 19/22 and 21/30 were most appropriate for simulator and patient-based assessment, respectively. We have validated a novel assessment tool for Duplex venous reflux measurement. Further work is required to establish transference validity of simulator training to improve skill in scanning patients. We have developed and validated V-DUOSATS for simulator training. Copyright © 2015 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

  17. Duplex gall bladder: bystander or culprit.

    Science.gov (United States)

    Kumar, Jogender; Yadav, Arushi

    2017-08-30

    Gall bladder (GB) duplication is a rare anatomical malformation, which can be detected by preoperative imaging study. We present a case of duplex gall bladder in a 14-year-old boy who presented with abdominal pain. On ultrasound, he had right nephrolithiasis and duplex gall bladder. Duplex gall bladder was confirmed on MR cholangiopancreatography. There was a dilemma for surgical management of duplex gall bladder; however, he became asymptomatic after conservative treatment. Prophylactic surgery is not recommended for asymptomatic incidentally detected duplex gall bladder. Radiologists and paediatric surgeons should be sensitised about the exact anatomy of this entity. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  18. The usefulness of Duplex Doppler ultrasound in the angiological and dermatological diagnosis of patients with blue toe syndrome.

    Science.gov (United States)

    Pawlaczyk, Katarzyna; Gabriel, Marcin; Strzelecka-Węklar, Daria A; Krasiński, Zbigniew; Stanisic, Michal; Gabriel, Zofia; Dzieciuchowicz, Łukasz; Adamski, Zygmunt

    2017-10-01

    Peripheral microembolism is one of the most frequent causes of acute limb ischemia. In order to effectively prevent relapses it is essential to localize and eliminate the source of embolism. To evaluate the role of Duplex Doppler ultrasound examination in identifying the causes of blue toe syndrome (BTS). The group of 165 patients with clinical symptoms of BTS on their upper limbs ( n = 16) and lower limbs ( n = 149) was investigated. They all underwent Duplex Doppler ultrasound of the major arteries of the extremities, where ischemic changes occurred. Morphological and functional changes which might be potential sources of microembolism were identified in 146 patients. These changes included significant short-length stenoses or unstable atherosclerotic plaque ( n = 73), true aneurysms ( n = 42) and pseudoaneurysms ( n = 17). In 11 cases, pathology of vascular prostheses in the form of anastomotic aneurysms, infection and residual thrombi after fibrinolysis was detected. In all cases, Duplex diagnosis was confirmed by other imaging and intraoperative tests. Duplex Doppler ultrasound of the arteries in the affected limb with a full length view should be the first-line examination in diagnosing patients with BTS. In the absence of hemodynamic blood flow disturbances in the major arteries in patients with symptoms of BTS, it is advisable to start haematological tests to identify/exclude congenital or acquired thrombophilia.

  19. Ultrasound and MR-imaging in preoperative evaluation of two rare cases of scar endometriosis

    OpenAIRE

    Pados, George; Tympanidis, John; Zafrakas, Menelaos; Athanatos, Dimitrios; Bontis, John N

    2008-01-01

    Scar or incisional endometriosis is a rare, often misdiagnosed, pathologic condition of the abdominal wall. Two cases of incisional endometriosis are presented. Both patients presented with atypical cyclic pain and palpable nodules on scars of previous cesarean sections. In both cases, the mass was totally excised, after accurate preoperative evaluation with 2-D ultrasound, power Doppler and MRI. Microscopic examination confirmed the preoperatively presumed diagnosis of cutaneous endometriosi...

  20. Duplex ultrasound: A diagnostic tool for carotid stenosis management in type 2 diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Yogan Kisten

    2013-07-01

    Full Text Available Background: Diabetic patients are at increased risk of developing cardiac events and stroke, and prevention of diabetes mellitus is therefore desirable. Marked geographical and ethnic variation in the prevalence of diabetes caused by urbanisation, demographic and epidemiological transitions has rendered this one of the major non-communicable diseases in South Africa. Duplex ultrasound (DUS plays an important role in primary health care in early detection of carotid atherosclerotic disease and the degree of carotid stenosis present. It is a reliable, cost-effective and non-invasive diagnostic tool. The purpose of this study was to determine the role of ultrasound in carotid stenosis management in type 2 diabetes mellitus (T2DM. Objectives: To determine the prevalence of carotid stenosis in a selected T2DM population using DUS and to correlate these findings with other predisposing atherosclerotic risk factors. Methods: The study setting was at an academic hospital in the Western Cape using carotid DUS reports of 103 diabetic subjects ≥ 35 years old. Predisposing risk factors were correlated with degree of carotid stenosis present. Data were analysed using the Fischer exact test, Chisquare and Student t-test. Results: Carotid DUS reports of 63 out of 103 T2DM patients revealed no evidence of a carotid stenosis, thereby lowering the risk profile. Forty patients were identified as having carotidstenosis; 22 symptomatic patients had a > 70% carotid stenosis which warranted surgicalintervention. A greater prevalence of stenosis in the Caucasian group, in both the male (p =0.0411 and female (p = 0.0458 cohorts, was noted. The overall trend suggested a relationship between T2DM and lifestyle, and a statistically significant relationship (p = 0.0063 between smoking and carotid stenosis was observed. Conclusion: T2DM and predisposing atherosclerotic risk factors significantly increased thepossibility of carotid stenosis development.

  1. Carotid duplex ultrasound and transcranial Doppler findings in commercial divers and pilots.

    Science.gov (United States)

    Dormanesh, Banafshe; Vosoughi, Kia; Akhoundi, Fahimeh H; Mehrpour, Masoud; Fereshtehnejad, Seyed-Mohammad; Esmaeili, Setareh; Sabet, Azin Shafiee

    2016-12-01

    The risky working environments of divers and pilots, and the possible role of extreme ambient pressure in carotid stenosis, make ischemic stroke an important occupational concern among these professionals. In this study, we aimed to evaluate the association of being exposed to hyperbaric or hypobaric conditions with carotid artery stenosis by comparing common carotid intima-media thickness (CCIMT) and blood flow velocities of cerebral arteries in divers and pilots using carotid duplex ultrasound (CDUS) and transcranial Doppler (TCD). CDUS and transtemporal TCD were performed in 29 divers, 36 pilots and 30 control participants. Medical history, blood pressure, lipid profile and blood sugar were recorded to control the previously well-known risk factors of atherosclerosis. Findings of the CDUS and TCD [including: CCIMT and blood flow velocities of internal carotid artery (ICA), common carotid artery (CCA), and middle cerebral artery (MCA)] of divers and pilots were compared with those of the control group using regression analysis models. Both right and left side CCIMT were significantly higher in divers (P < 0.05) and pilots (P < 0.05) in comparison with the control group. Carotid index [peak systolic velocity (PSV) of ICA/PSV of CCA) of divers and pilots were also higher than the control group. TCD findings were not significantly different between divers, pilots, and the control group. Increased CCIMT and carotid index in diver and pilot groups appear to be suggestive of accelerated atherosclerosis of carotid artery in these occupational groups.

  2. Comparison of Colour Duplex Ultrasound with Computed Tomography to Measure the Maximum Abdominal Aortic Aneurysmal Diameter

    Directory of Open Access Journals (Sweden)

    C. Gray

    2014-01-01

    Full Text Available Introduction. Maximum diameter of an abdominal aortic aneurysm (AAA is the main indication for surgery. This study compared colour duplex ultrasound (CDU and computed tomography (CT in assessing AAA diameter. Patients and Methods. Patients were included if they had both scans performed within 90 days. Pearson’s correlation coefficient, paired t-test, and limits of agreement (LOA were calculated for the whole group. Subgroup analysis of small (6.5 cm aneurysms was performed. A P value of <0.05 was considered statistically significant. Results. 389 patients were included, giving 130 pairs of tests for comparison. Excellent correlation was in the whole group (r = 0.95 and in the subgroups (r = 0.94; 0.69; 0.96, resp.. Small LOA between the two imaging modalities was found in all subgroups. Conclusion. Small aneurysms can be accurately measured using CDU. CDU is preferable for small AAAs, but cannot supplant CT for planning aortic intervention.

  3. Observer agreement of lower limb venous reflux assessed by duplex ultrasound scanning using manual and pneumatic cuff compression in patients with chronic venous disease and controls

    DEFF Research Database (Denmark)

    Broholm, R; Kreiner, S; Bækgaard, Niels

    2011-01-01

    The study aimed to evaluate observer agreement between two experienced ultrasound operators examining deep venous reflux assessed by duplex ultrasound (DU) using either manual or pneumatic cuff compression. In addition, the two methods were compared with each other with regard to immediate "eyeba...... "eyeballing" and direct measurements of reflux time from Doppler flow curves....

  4. Preoperative Thyroid Ultrasound Is Indicated in Patients Undergoing Parathyroidectomy for Primary Hyperparathyroidism

    Directory of Open Access Journals (Sweden)

    Cletus A. Arciero, Zita S. Shiue, Jeremy D. Gates, George E. Peoples, Alan P. B. Dackiw, Ralph P. Tufano, Steven K. Libutti, Martha A. Zeiger, Alexander Stojadinovic

    2012-01-01

    Full Text Available Background: Primary hyperaparathyroidism (pHPT is often accompanied by underlying thyroid pathology that can confound preoperative parathyroid localization studies and complicate intra-operative decision making. The aim of this study was to examine the utility of preoperative thyroid ultrasonography (US in patients prior to undergoing parathyroidectomy for pHPT.Methods: An Institutional Review Board approved prospective study was undertaken from January 2005 through July 2008. All patients with pHPT meeting inclusion criteria (n=94 underwent preoperative thyroid ultrasound in addition to standard 99mTc-sestamibi scintigraphy for parathyroid localization. Demographics, operative management and final pathology were examined in all cases.Results: Fifty-four of the 94 patients (57% were noted to have a thyroid nodule on preoperative US, of which 30 (56% underwent further examination with fine needle aspiration biopsy. Alteration of the operative plan attributable to underlying thyroid pathology occurred in 16 patients (17%, with patients undergoing either total thyroidectomy (n=9 or thyroid lobectomy (n=7. Thyroid cancer was noted in 33% of patients undergoing thyroid resection, and 6% of all patients with HPT.Conclusions: The routine utilization of preoperative thyroid ultrasound in patients prior to undergoing parathyroid surgery for pHPT is indicated. The added information from this non-invasive modality facilitates timely management of co-incidental, and sometimes malignant, thyroid pathology.

  5. Intrarectal ultrasound accuracy in preoperative staging of lower rectal cancer

    International Nuclear Information System (INIS)

    Vallone, G.; Della Vecchia, A.; Di Capua, V.; Rengo, C.; Spirito, M.; Romano, G.

    1988-01-01

    The capabilities were evaluated of endorectal ultrasound in assessing the local extension of rectal carcinomas. The study population consisted of 50 patients with histologically proven rectal cancer. A CT scan was also performed on 45 patients, and the results were then compared to post-operative histologic findings. Endorectal US allowed the correct staging of 39/45 tumors (86.6%), with 1 false positive (overstaging T1 as T2), and 5 false negatives (understaging 3xT3 as T2; 2xT4 as T3). CT allowed the correct staging of 37/45 tumors (82.2%), with 5 false positives (overstaging T1 as T2) and 3 false negatives (understaging T3 as T2). Our results prove endorectal US to be a reliable method for the local staging of rectal cancers, limited to mucosa, submucosa and muscular layers of the rectal wall (T1 and T2 tumors). CT does not allow proper evaluation of T1 and T2 tumors, but provides with a better assessment of tumors (T3 and T4). Both C and endorectal US should, therefore, be used as complementary diagnostic techniques for an accurate evaluation of the local extension of lower rectal cancers

  6. Pleural ultrasound as an adjunct to physical examination in the preoperative evaluation of lung cancer patients.

    Science.gov (United States)

    Bah, Ismaël; Goudie, Eric; Khereba, Mohamed; Ferraro, Pasquale; Duranceau, André; Martin, Jocelyne; Thiffault, Vicky; Liberman, Moishe

    2014-05-01

    Preoperative evaluation of patients with suspected or confirmed lung cancer consists of clinical and radiological staging. Malignant pleural effusion is a poor prognosticator in non-small-cell lung cancer. Pleural ultrasound (PU) allows for the assessment of pleural effusion, providing real-time guidance for its aspiration and cytological analysis. Pleural Ultrasonography in Lung Cancer (PULC) as an adjunct to physical examination has the potential to improve preoperative staging of non-small-cell lung cancer during first surgical encounter by allowing the evaluation of previously unassessed pleural effusion. This study consisted of a prospective trial of surgeon-performed PU in the preoperative evaluation of lung cancer patients. All patients evaluated in the thoracic surgery clinic with the new or presumed diagnosis of lung cancer were eligible. A portable ultrasound machine was used to evaluate pleural fluid in the bilateral costophrenic sulci with pleural fluid aspiration for cytological analysis. Forty-five patients were prospectively enrolled over a 3-month period. Thirteen patients had ultrasound evidence of a pleural effusion, of which 3 were significant enough for aspiration. Cytological analysis of these effusions yielded malignant cells in 1 patient. Positive PULC evaluation led to a change in clinical staging (M0 to M1a) in 10 patients and a change in pathological staging (pleural fluid cytology positive) in 1 patient. The time required for PULC examination was 15 ± 7 min. There were no complications related to the procedures. Preoperative pleural ultrasonography is a rapid and effective way to improve precision of staging in patients with lung cancer. More precise staging may allow for more appropriate testing, patient prognostication and operative planning.

  7. Preoperative 4D CT Localization of Nonlocalizing Parathyroid Adenomas by Ultrasound and SPECT-CT.

    Science.gov (United States)

    Hinson, Andrew M; Lee, David R; Hobbs, Bradley A; Fitzgerald, Ryan T; Bodenner, Donald L; Stack, Brendan C

    2015-11-01

    To evaluate 4-dimensional (4D) computed tomography (CT) for the localization of parathyroid adenomas previously considered nonlocalizing on ultrasound and single-photon emission CT with CT scanning (SPECT-CT). To measure radiation exposure associated with 4D-CT and compared it with SPECT-CT. Case series with chart review. University tertiary hospital. Nineteen adults with primary hyperparathyroidism who underwent preoperative 4D CT from November 2013 through July 2014 after nonlocalizing preoperative ultrasound and technetium-99m SPECT-CT scans. Sensitivity, specificity, predictive values, and accuracy of 4D CT were evaluated. Nineteen patients (16 women and 3 men) were included with a mean age of 66 years (range, 39-80 years). Mean preoperative parathyroid hormone level was 108.5 pg/mL (range, 59.3-220.9 pg/mL), and mean weight of the excised gland was 350 mg (range, 83-797 mg). 4D CT sensitivity and specificity for localization to the patient's correct side of the neck were 84.2% and 81.8%, respectively; accuracy was 82.9%. The sensitivity for localizing adenomas to the correct quadrant was 76.5% and 91.5%, respectively; accuracy was 88.2%. 4D CT radiation exposure was significantly less than the radiation associated with SPECT-CT (13.8 vs 18.4 mSv, P = 0.04). 4D CT localizes parathyroid adenomas with relatively high sensitivity and specificity and allows for the localization of some adenomas not observed on other sestamibi-based scans. 4D CT was also associated with less radiation exposure when compared with SPECT-CT based on our study protocol. 4D CT may be considered as first- or second-line imaging for localizing parathyroid adenomas in the setting of primary hyperparathyroidism. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2015.

  8. Real-Time MRI Navigated Ultrasound for Preoperative Tumor Evaluation in Breast Cancer Patients: Technique and Clinical Implementation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ah Young; Seo, Bo Kyoung [Department of Radiology, Korea University Ansan Hospital, Korea University College of Medicine, Ansan 15355 (Korea, Republic of)

    2016-11-01

    Real-time magnetic resonance imaging (MRI) navigated ultrasound is an image fusion technique to display the results of both MRI and ultrasonography on the same monitor. This system is a promising technique to improve lesion detection and analysis, to maximize advantages of each imaging modality, and to compensate the disadvantages of both MRI and ultrasound. In evaluating breast cancer stage preoperatively, MRI and ultrasound are the most representative imaging modalities. However, sometimes difficulties arise in interpreting and correlating the radiological features between these two different modalities. This pictorial essay demonstrates the technical principles of the real-time MRI navigated ultrasound, and clinical implementation of the system in preoperative evaluation of tumor extent, multiplicity, and nodal status in breast cancer patients.

  9. Real-time MRI navigated ultrasound for preoperative tumor evaluation in breast cancer patients: Technique and clinical implementation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ah Young; Seo, Bo Kyoung [Dept. of Radiology, Korea University Ansan Hospital, Korea University College of Medicine, Ansan (Korea, Republic of)

    2016-09-15

    Real-time magnetic resonance imaging (MRI) navigated ultrasound is an image fusion technique to display the results of both MRI and ultrasonography on the same monitor. This system is a promising technique to improve lesion detection and analysis, to maximize advantages of each imaging modality, and to compensate the disadvantages of both MRI and ultrasound. In evaluating breast cancer stage preoperatively, MRI and ultrasound are the most representative imaging modalities. However, sometimes difficulties arise in interpreting and correlating the radiological features between these two different modalities. This pictorial essay demonstrates the technical principles of the real-time MRI navigated ultrasound, and clinical implementation of the system in preoperative evaluation of tumor extent, multiplicity, and nodal status in breast cancer patients.

  10. Efficacy of duplex ultrasound surveillance after infrainguinal vein bypass may be enhanced by identification of characteristics predictive of graft stenosis development.

    Science.gov (United States)

    Tinder, Chelsey N; Chavanpun, Joe P; Bandyk, Dennis F; Armstrong, Paul A; Back, Martin R; Johnson, Brad L; Shames, Murray L

    2008-09-01

    Controversy regarding the efficacy of duplex ultrasound surveillance after infrainguinal vein bypass led to an analysis of patient and bypass graft characteristics predictive for development of graft stenosis and a decision of secondary intervention. Retrospective analysis of a contemporary, consecutive series of 353 clinically successful infrainguinal vein bypasses performed in 329 patients for critical (n = 284; 80%) or noncritical (n = 69; 20%) limb ischemia enrolled in a surveillance program to identify and repair duplex-detected graft stenosis. Variables correlated with graft stenosis and bypass repair included: procedure indication, conduit type (saphenous vs nonsaphenous vein; reversed vs nonreversed orientation), prior bypass graft failure, postoperative ankle-brachial index (ABI) < 0.85, and interpretation of the first duplex surveillance study as "normal" or "abnormal" based on peak systolic velocity (PSV) and velocity ratio (Vr) criteria. Overall, 126 (36%) of the 353 infrainguinal bypasses had 174 secondary interventions (endovascular, 100; surgery, 74) based on duplex surveillance; resulting in 3-year Kaplan-Meier primary (46%), assisted-primary (80%), and secondary (81%) patency rates. Characteristics predictive of duplex-detected stenosis leading to intervention (PSV: 443 +/- 94 cm/s; Vr: 8.6 +/- 9) were: "abnormal" initial duplex testing indicating moderate (PSV: 180-300 cm/s, Vr: 2-3.5) stenosis (P < .0001), non-single segment saphenous vein conduit (P < .01), warfarin drug therapy (P < .01), and redo bypass grafting (P < .001). Procedure indication, postoperative ABI level, statin drug therapy, and vein conduit orientation were not predictive of graft revision. The natural history of 141 (40%) bypasses with an abnormal first duplex scan differed from "normal" grafts by more frequent (51% vs 24%, P < .001) and earlier (7 months vs 11 months) graft revision for severe stenosis and a lower 3-year assisted primary patency (68% vs 87%; P < .001). In 52

  11. MRI, PET/CT and ultrasound in the preoperative staging of endometrial cancer - A multicenter prospective comparative study

    DEFF Research Database (Denmark)

    Antonsen, Sofie Leisby; Jensen, Lisa Neerup; Loft, Annika

    2012-01-01

    OBJECTIVES: The aim of this prospective multicenter study was to evaluate and compare the diagnostic performance of PET/CT, MRI and transvaginal two-dimensional ultrasound (2DUS) in the preoperative assessment of endometrial cancer (EC). METHODS: 318 consecutive women with EC were included when...

  12. Evaluation of the erectile dysfunction of vascular origin by means of the ultrasound Doppler Duplex

    International Nuclear Information System (INIS)

    Varon, Claudia; Aponte, Hernan Alonso; Poveda, Alvaro; Rubiano, Nicolas; Serrano, Adolfo

    1996-01-01

    We studied 20 patients with erectile dysfunction of vascular origin and 10 patients with psychological erectile dysfunction with Doppler ultrasound before and after injection of intra cavernous vasoactive substances. We observed that psychological erectile dysfunction, is characterized by normal vascular velocities in cavernous arteries (control group). In patients with vascular aetiology we obtained abnormal registrations that differentiated arterial from venous pathology. There was a significant difference in the diameter of the cavernous artery and the systolic flow after the injection of vasoactive substances

  13. CLINICOPATHOLOGICAL FACTORS ASSOCIATED WITH POSITIVE PREOPERATIVE AXILLARY ULTRASOUND SCANNING IN BREAST CANCER PATIENTS

    Directory of Open Access Journals (Sweden)

    Lona Jalini

    2016-01-01

    Full Text Available Background: Axillary lymph node status is the most important breast cancer prognostic factor. Preoperative axillary ultrasound examination (PAUS is used to triage patients for sentinel lymph node biopsy (SLNB or axillary lymph node dissection (ALND. We assessed the detection rate of lymph node metastases by PAUS in a screening unit and evaluated associations between clinicopathological factors and PAUS positivity. Patients and Methods: This was a single-centre retrospective analysis of data extracted from a hospital breast cancer database and clinical records. Clinical, radiological, and pathological and prognostic indices were compared between PAUS-positive and PAUS-negative patients subsequently found to have lymph node metastases on histopathological analysis. Results: Two hundred and two patients were eligible for analysis. 50.5% of lymph node-positive patients were correctly identified as PAUS positive. Patients with PAUS-positive lymph nodes had less favorable disease characteristics, namely clinically palpable lymph nodes, higher Nottingham prognostic (NPI index, high lymph node burden according to the European Society of Medical Oncology (ESMO group classification, and larger, grade 3 tumors with lymphovascular invasion and extranodal spread. Moreover, PAUS-positive patients had more macrometastases and lymph node involvement than PAUS-negative patients. Conclusion: PAUS-positive patients and PAUS-negative (SLNB-positive patients have different clinicopathological characteristics. The presence of LVI, extranodal spread, grade 3 histology, or large tumors with poor prognostic indices in PAUS-negative patients should be regarded with caution and perhaps prompt second-look ultrasound examination.

  14. Duplex ultrasound in aneurysm surveillance following endovascular aneurysm repair: a comparison with computed tomography aortography.

    LENUS (Irish Health Repository)

    Manning, Brian J

    2012-02-01

    OBJECTIVES: Cumulative radiation dose, cost, and increased demand for computed tomography aortography (CTA) suggest that duplex ultrasonography (DU) may be an alternative to CTA-based surveillance. We compared CTA with DU during endovascular aneurysm repair (EVAR) follow-up. METHODS: Patients undergoing EVAR had clinical and radiological follow-up data entered in a prospectively maintained database. For the purpose of this study, the gold standard test for endoleak detection was CTA, and an endoleak detected on DU alone was assumed to be a false positive result. DU interpretation was performed independently of CTA and vice versa. RESULTS: One hundred thirty-two patients underwent EVAR, of whom 117 attended for follow-up ranging from six months to nine years (mean, 32 months). Adequate aneurysm sac visualisation on DU was not possible in 1.7% of patients, predominantly due to obesity. Twenty-eight endoleaks were detected in 28 patients during follow-up. Of these, 24 were initially identified on DU (four false negative DU examinations), and eight had at least one negative CTA with a positive DU prior to diagnosis. Twenty-three endoleaks were type II in nature and three of these patients had increased sac size. There was one type I and four type III endoleaks. Two of these (both type III) had an increased sac size. Of 12 patients with increased aneurysm size of 5 mm or more at follow-up, five had an endoleak visible on DU, yet negative CTA and a further five had endoleak visualisation on both DU and CTA. Of six endoleaks which underwent re-intervention, all were initially picked up on DU. One of these endoleaks was never demonstrated on CTA and a further two had at least one negative CTA prior to endoleak confirmation. Positive predictive value for DU was 45% and negative predictive value 94%. Specificity of DU for endoleak detection was 67% when compared with CTA, because of the large number of false positive DU results. Sensitivity for DU was 86%, with all

  15. The value of preoperative ultrasound guided fine-needle aspiration cytology of radiologically suspicious axillary lymph nodes in breast cancer

    Directory of Open Access Journals (Sweden)

    Torill Sauer

    2014-01-01

    Full Text Available Background: Preoperative ultrasound (US and eventually US-guided fine-needle aspiration cytology (FNAC of suspicious axillary lymph nodes (ALN is a standard procedure in the work-up of suspicious breast lesions. Preoperative US FNAC may prevent sentinel node biopsy (SNB procedure in 24-30% of patients with early stage breast carcinoma. The aim of this study was to evaluate the institutional results of this preoperative diagnostic procedure. Materials and Methods: A total of 182 cases of preoperative FNAC of suspicious ALN where retrieved from the pathology files. The results were compared with the final histology and staging. False negative (FN FNAC cases were reviewed and possibly missed metastatic cases (2 were immunostained with the epithelial marker AE1/AE3. Results: There were no false positives, whereas 16 cases were FN. In all but one case the FN′s represented sampling error. Half of the 16 FN cases in this series were macrometastases. Discussion: About 83% of the preoperatively aspirated cases were N+, indicating that a radiologically suspicious ALN has a very high risk of being metastatic. Preoperative US guided FNAC from radiologically suspicious ALN is highly efficient in detecting metastases. Depending on national guidelines, a preoperative, positive ALN FNAC might help to stratify the patients as to SNB and/or ALN dissection.

  16. Incidental enhancing lesions found on preoperative breast MRI: management and role of second-look ultrasound.

    Science.gov (United States)

    Luciani, M L; Pediconi, F; Telesca, M; Vasselli, F; Casali, V; Miglio, E; Passariello, R; Catalano, C

    2011-09-01

    This study prospectively assessed second-look ultrasound (US) for the evaluation of incidental enhancing lesions identified on preoperative breast magnetic resonance imaging (MRI). Between 2004 and 2007, 182 patients with malignant breast lesions detected on US and/or X-ray mammography and confirmed by cytology/histology underwent preoperative breast contrast-enhanced (CE)-MRI. Patients with incidental lesions on breast MRI underwent second-look high-resolution US directed at the site of the incidental finding. Diagnosis of incidental lesions was based on biopsy or 24-month follow-up. Breast MRI detected 55 additional lesions in 46/182 (25.2%) patients. Forty-two of 55 (76.3%) lesions were detected on second-look US in 38/46 (82.6%) patients. Malignancy was confirmed for 24/42 (57.1%) correlate lesions compared with 7/13 (53.8%) noncorrelate lesions. Second-look US depicted 8/9 (88.8%) Breast Imaging Reporting and Data System (BI-RADS) 5, 16/22 (72.7%) BI-RADS 4 and 18/24 (75%) BI-RADS 3 lesions. Sensitivity, specificity, accuracy and positive and negative predictive values for lesion detection/diagnosis was 100%, 88.9%, 94.6%, 90.3% and 100% for MRI and 64.3%, 70.4%, 67.3%, 69.2% and 65.5% for second-look US. Improved performance for US was obtained when masslike lesions only were considered. Second-look US is a confirmatory method for incidental findings on breast MRI, particularly for mass-like lesions.

  17. Preoperative axillary lymph node staging by ultrasound-guided cytology using a four-level sonographic score

    International Nuclear Information System (INIS)

    De Coninck, Caroline; Noël, Jean-Christophe; Boutemy, Rachel; Simon, Philippe

    2016-01-01

    The staging of axillary lymph nodes is critical to the management and prognosis of breast cancer, the most frequent cancer in females. Neoadjuvant therapy and lymph node dissection are recommended when malignant cells invade the lymph nodes. Therefore the pre-operative examination of these lymph nodes is crucial to treatment. In this study, we examined the effectiveness of cytology through ultrasound-guided fine needle aspiration (USG-FNA) and ultrasound (US) imaging using an established classification system in correctly identifying lymph node status compared to the final histological results after surgery. Cytology by USG-FNA and US classification were found to be promising methods of axillary lymph node staging. US and CB offer minimally invasive techniques to pre-operatively examine these lymph nodes in patients with primary breast cancer

  18. Preoperative magnetic resonance and intraoperative ultrasound fusion imaging for real-time neuronavigation in brain tumor surgery.

    Science.gov (United States)

    Prada, F; Del Bene, M; Mattei, L; Lodigiani, L; DeBeni, S; Kolev, V; Vetrano, I; Solbiati, L; Sakas, G; DiMeco, F

    2015-04-01

    Brain shift and tissue deformation during surgery for intracranial lesions are the main actual limitations of neuro-navigation (NN), which currently relies mainly on preoperative imaging. Ultrasound (US), being a real-time imaging modality, is becoming progressively more widespread during neurosurgical procedures, but most neurosurgeons, trained on axial computed tomography (CT) and magnetic resonance imaging (MRI) slices, lack specific US training and have difficulties recognizing anatomic structures with the same confidence as in preoperative imaging. Therefore real-time intraoperative fusion imaging (FI) between preoperative imaging and intraoperative ultrasound (ioUS) for virtual navigation (VN) is highly desirable. We describe our procedure for real-time navigation during surgery for different cerebral lesions. We performed fusion imaging with virtual navigation for patients undergoing surgery for brain lesion removal using an ultrasound-based real-time neuro-navigation system that fuses intraoperative cerebral ultrasound with preoperative MRI and simultaneously displays an MRI slice coplanar to an ioUS image. 58 patients underwent surgery at our institution for intracranial lesion removal with image guidance using a US system equipped with fusion imaging for neuro-navigation. In all cases the initial (external) registration error obtained by the corresponding anatomical landmark procedure was below 2 mm and the craniotomy was correctly placed. The transdural window gave satisfactory US image quality and the lesion was always detectable and measurable on both axes. Brain shift/deformation correction has been successfully employed in 42 cases to restore the co-registration during surgery. The accuracy of ioUS/MRI fusion/overlapping was confirmed intraoperatively under direct visualization of anatomic landmarks and the error was surgery and is less expensive and time-consuming than other intraoperative imaging techniques, offering high precision and

  19. Preoperative ultrasound measurements predict the feasibility of gallbladder extraction during transgastric natural orifice translumenal endoscopic surgery cholecystectomy.

    Science.gov (United States)

    Santos, Byron F; Auyang, Edward D; Hungness, Eric S; Desai, Kush R; Chan, Edward S; van Beek, Darren B; Wang, Edward C; Soper, Nathaniel J

    2011-04-01

    Extraction of a gallbladder through an endoscopic overtube during natural orifice translumenal endoscopic surgery (NOTES) transgastric cholecystectomy avoids potential injury to the esophagus. This study examined the rate of successful gallbladder specimen extraction through an overtube and hypothesized that preoperative ultrasound findings could predict successful specimen passage. Gallbladder specimens from patients undergoing laparoscopic cholecystectomy were measured, and an attempt was made to pull the specimens through a commercially available overtube with an inner diameter of 16.7-mm. A radiologist blinded to the outcomes reviewed the available preoperative ultrasound measurements from these patients. Ultrasound dimensions including gallbladder length, width, and depth; wall thickness; common bile duct diameter; and size of the largest gallstone (LGS) were recorded. Multiple logistic regression analysis was performed to determine whether ultrasound findings and patient characteristics (age, body mass index [BMI], and sex) could predict the ability of a specimen to pass through the overtube. Of 57 patients, 44 (77%) who had preoperative ultrasounds available for electronic review were included in the final analysis. Gallstones were present in 35 (79%) of these 44 patients. Intraoperative gallbladder perforation occurred in 18 (41%) of the 44 patients, and 16 (36%) of the 44 gallbladders could be extracted through the overtube. Measurement of LGS was possible for 23 patients, and indeterminate gallstone size (IGS) was determined for 12 patients. The rate for passage of perforated versus intact gallbladders was similar (40% vs. 23%; p = 0.054). The LGS (odds ratio [OR], 1.17; 95% confidence interval [CI], 1.02-1.33; p = 0.021) and IGS (OR, 22.97; 95% CI, 1.99-265.63; p = 0.025) predicted failed passage on multivariate logistic regression analysis. The passage rate was 80% for LGS smaller than 10 mm or no stones present, 18% for LGS 10 mm or larger, and 8% for

  20. Penile vascular diagnostic categorization using penile duplex Doppler ultrasound: Differences in vascular hemodynamics parameters by differences in anatomic sampling location

    Directory of Open Access Journals (Sweden)

    Fabio Pezzoni

    2016-10-01

    Full Text Available Objectives. In 2013 the International Society for Sexual Medicine(ISSM published the guidelines regarding the standard operating procedure (SOP for penile duplex Doppler ultrasound (PDDU. Although ISSM-SOP have given important strides in reducing interobserver variability in PDDU by procedural protocol and parameters these guidelines do not address the anatomic location along the penis at which hemodynamic measurements have to be done. In our opinion a “double sampling” may be interesting to detect the arteriogenic or venogenic nature of the erectile dysfunction (ED. In particular sampling measurements at the “crus” (at the level of the peno-scrotal junction may be significative for detection of veno-occlusive dysfunction (VOD,whereas an evaluation at “mid penis” (1/2 distance between peno-scrotal junction and coronal sulcus, may be useful to diagnose an arterial insufficiency (AI. Material and Methods. We evalued 90 men, mean age 56.3, affected with ED of medium degree, responder to PDE5-I that urdergone to PDDU and also responder after pharmacologic intracavernosal injection (PIIof prostaglandin E1 20 mcg, with rigid erection and normal maintenance. We moreover evalued 90 men in youthful age (mean 35.2, in absence of vascular risk factors, no responder to PDE5-I that undergone to PDDU by PII at high dosage (bimix: prostaglandin E1 20 mcg, papaverine 20 mg. Results. In the first pool the sampling at “mid penis” resulted significative for arterial insuffciency (AI in 81% (73, in presence of normal or borderline end diastolic velocity (EDV. Sampling at the “crus” resulted negative for VOD in 90% (81. In the second pool, 66.6% (60 resulted responder with rigid erection and normal maintenance in presence of normal hemodynamic parameters: peak systolic velocity (PSV and end diastolic velocity (EDV both at the “crus” and at “mid penis” sampling. 33.4% (30 responded with a semirigid erection and manifested a constant

  1. Duplex-guided percutaneous transluminal angioplasty in iliac arterial occlusive disease.

    Science.gov (United States)

    Krasznai, A G; Sigterman, T A; Welten, R J; Heijboer, R; Sikkink, C J J M; van de Akker, L H J M; Bouwman, L H

    2013-11-01

    Chronic renal insufficiency (CRI) is a growing global problem. PTA can be performed without nephrotoxic contrast, utilizing Doppler-ultrasound (Duplex) guidance. Duplex-guided infra-inguinal interventions and access-related interventions have been reported. Duplex-guided iliac interventions have not been performed to any extent because of the anatomic location. In our study we evaluated the safety and efficacy of Duplex-guided percutaneous transluminal angioplasty (DuPTA) in iliac arteries. From June 2012 until February 2013, 31 patients (35 iliac lesions), underwent DuPTA. Indications ranged from Rutherford 3 to 5. Preoperative evaluation included Ankle Brachial Index (ABI), Duplex and MRA. Procedural success was defined as crossing the lesion with a guidewire and dilating or stenting the lesion. Clinical success was defined as 50% reduction in peak systolic velocity (PSV) or clinical improvement. PSV was evaluated after PTA, then at 2 weeks. Clinical results were assessed 2 weeks after the procedure. Procedural success was achieved in 94% of patients (33/35), all of whom also had clinical success. Post-procedural PSV reduction showed an average improvement of 63% (431 cm/s to 153 cm/s). Mean preoperative ABI was 0.72 and improved to 0.88 postoperatively. PTA using Duplex-guidance in significant iliac stenosis is a safe method with major advantages in patients at high risk for developing contrast-induced nephropathy. Copyright © 2013 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

  2. Ten-year technical and clinical outcomes in TransAtlantic Inter-Society Consensus II infrainguinal C/D lesions using duplex ultrasound arterial mapping as the sole imaging modality for critical lower limb ischemia.

    LENUS (Irish Health Repository)

    Sultan, Sherif

    2013-04-01

    The aim of this study was to evaluate duplex ultrasound arterial mapping (DUAM) as the sole imaging modality when planning for bypass surgery (BS) and endovascular revascularization (EvR) in patients with critical limb ischemia for TransAtlantic Inter-Society Consensus (TASC) II C\\/D infrainguinal lesions.

  3. Preoperative evaluation of hyperparathyroidism. The role of dual-phase parathyroid scintigraphy and ultrasound imaging

    International Nuclear Information System (INIS)

    Sukan, A.; Reyhan, M.; Aydin, M.; Yapar, A.F.; Aktas, A.; Sert, Y.; Canpolat, T.

    2008-01-01

    The aim of this study was to evaluate the efficacy of dual-phase 99mTc-methoxyisobutylnitrile (MIBI) parathyroid scintigraphy (PS) and ultrasound (US) in primary (pHPT) and secondary (sHPT) hyperparathyroidism. A total of 69 patients (mean age 47±16; age range 14-79 years), including 19 patients with sHPT were enrolled in this study. Preoperative serum intact parathyroid hormone (iPTH) levels, calcium (Ca), phosphate (P), alkaline phosphatase, and 24-h urinary-free Ca measurements were obtained. Concomitant thyroid pathology was also recorded. Histopathology revealed 30 solitary adenomas and 71 hyperplastic glands in 55 patients. The remaining patients' histopathology revealed normal parathyroid, thyroid, or lymph nodes. The sensitivities of MIBI and US in pUPT were 70% and 60%, respectively. It was 60% for both procedures in sHPT. The overall sensitivity of combined US+MIBI in pHPT and sHPT was 81% and 71%, respectively. The overall specificity of MIBI and US was 87% and 91%; positive predictive value (PPV) was 94% and 92%, respectively. MIBI and US identified the parathyroid pathology in 92% and 85% of patients in the non-concomitant thyroid disease group, and in 53% and 47% of patients in the concomitant thyroid disease group, respectively. The weight of the gland between primary and secondary hyperparathyroidism did not reveal a significant difference (P=0.4). Significant differences were found with respect to age, PTH, Ca, and P levels between the pHPT and sHPT (P<0.001). Intact PTH levels showed significant differences between MIBI positive and negative patients (P=0.013), and also US positive and negative patients (P=0.012). A significant negative correlation was found between iPTH and Ca at sHPT (P<0.001). The concomitancy of thyroid disease greatly influences scintigraphic and ultrasonographic detection of parathyroid pathology in pHPT and sHPT. The combination of MIBI and US appears promising for localizing parathyroid pathology in patients with both

  4. Management of anterior triangle swellings in a tertiary vascular centre with emphasis on the roles of duplex ultrasound, computed tomography angiogram and magnetic resonance angiogram: a case series.

    LENUS (Irish Health Repository)

    Colleran, Gabrielle C

    2009-01-01

    BACKGROUND: Anterior triangle masses pose an important clinical dilemma. It is very difficult to distinguish the potential pathologies pre operatively by clinical and radiological assessment. CASE REPORT: The first case highlights the management of a bilateral chemodectoma, the second case is a presentation of castleman\\'s disease and the third is that of metastatic tonsillar adenocarcinoma. All three cases had a similar presentation and radiological appearance pre-operatively. CONCLUSION: Anterior triangle masses span the clinical spectrum of pathologies from chemodectoma to castleman\\'s disease to carcinoma. Expert vascular and radiological management is required for optimum patient care and should take place in a tertiary referral centre. Duplex US, CTA and MRA are important pre operative assessment tools to ensure that adequate information regarding the relationship of the lesion to the carotid artery is available to the operating surgeon who should have vascular expertise as deliberate practice volume has been repeatedly shown to result in improved patient outcome.

  5. Clinical utility of ultrasound and 99mTc sestamibi SPECT/CT for preoperative localization of parathyroid adenoma in patients with primary hyperparathyroidism

    International Nuclear Information System (INIS)

    Patel, C.N.; Salahudeen, H.M.; Lansdown, M.; Scarsbrook, A.F.

    2010-01-01

    Aim: To evaluate the accuracy of ultrasound and parathyroid scintigraphy using single photon-emission computed tomography/computed tomography (SPECT/CT) for the preoperative localization of solitary parathyroid adenomas in patients with primary hyperparathyroidism who would be suitable for minimally invasive parathyroid surgery. Materials and methods: Retrospective study of 63 consecutive patients with biochemical evidence of primary hyperparathyroidism referred for preoperative localization of parathyroid adenoma that proceeded to surgery in the same institution. All patients underwent high-resolution ultrasound and Technetium-99m sestamibi scintigraphy with planar and SPECT/CT imaging. The accuracy of preoperative imaging was compared to surgical and histological findings as the reference standard. Results: Fifty-nine patients had solitary parathyroid adenomas, three patients had multiglandular hyperplasia, and one patient had multiple parathyroid adenomas confirmed at surgery and histology. Thirty-five solitary parathyroid adenomas were identified preoperatively with ultrasound (64%) and 53 with SPECT-CT (90%). Concordant ultrasound and SPECT/CT findings were found in 35 cases (59%). An additional three adenomas were found with ultrasound alone and 18 adenomas with SPECT/CT alone. Fifty-one of the 56 adenomas localized using combined ultrasound and SPECT/CT were found at the expected sites during surgery. Combined ultrasound and SPECT/CT has an overall sensitivity of 95% and accuracy of 91% for the preoperative localization of solitary parathyroid adenomas. Conclusions: The combination of ultrasound and SPECT/CT has incremental value in accurately localizing solitary parathyroid adenomas over either technique alone, and allows selection of patients with primary hyperparathyroidism who would be suitable for minimally invasive surgery.

  6. Evaluation of portal hypertension in cirrhotic patients using color duplex-doppler ultrasound. Preliminary study; Evaluacion de la hipertension portal del cirrotico mediante ultrasonografia duplex-Doppler color. Estudio prliminar

    Energy Technology Data Exchange (ETDEWEB)

    Varas, M J; Torres, G; Sanllely, H [Unidad de Ecografias, Consorcio del Hospital de la Cruz Roja, L` Hospitalet de Llobregat, Barcelona (Spain)

    1996-09-01

    The objective was to compare data obtained by color duplex-Doppler ultrasound (mean velocity, flow and portal vein congestion index) in patients with chronic diffuse liver disease with and without portal hypertension (PH) (demonstrated endoscopically) with that of a healthy control group. Over a two-year period, 50 studies were performed in 10 healthy subjects (control group) with a mean age of 36 years and in 40 chronic liver disease patients (study group with a mean age of 58 years), most of whom presented alcoholic liver cirrhosis and belonged to Child-Pugh class B. They were subdivided according to endoscopic study into patients without (group 1) and with (group 2) portal hypertension. There were statistically significant differences in the diameters of splenic vein, spleen, portal vein and in the portal Vm, which decreased as the Child-Pugh score rose. When the patients without (group 1) and with (group 2) endoscopic evidence of PH (esophageal varices)were analyzed and compared, the two groups presented no statistically significant differences with respect to portal Vm, blood flow out of the liver, presence of collateral vessels, or the portal vein congestion index; the latter was significantly different in both the study group as a whole and in the patients with PH when compared with the control group. Given that this report is based on a pilot study which requires a larger sample number, we are unable to arrive at definitive conclusions. (Author) 18 refs.

  7. Surgeon-Performed Ultrasound as Preoperative Localization Study in Patients with Primary Hyperparathyroidism

    NARCIS (Netherlands)

    van Ginhoven, T. M.; Morks, A. N.; Schepers, T.; de Graaf, P. W.; Smit, P. C.

    2011-01-01

    Background: Minimally invasive parathyroidectomy is the treatment of choice for single-gland primary hyperparathyroidism. However, the exact location of the abnormal gland has to be established. Sestamibi scintigraphy, computed tomography and ultrasound (US) are commonly used modalities. We describe

  8. Comparison of IOL--master and ultrasound biometry in preoperative intra ocular lens (IOL) power calculation.

    Science.gov (United States)

    Kolega, Marija Škara; Kovačević, Suzana; Čanović, Samir; Pavičić, Ana Didović; Bašić, Jadranka Katušić

    2015-03-01

    Postoperative refractive outcome largely depends on the accuracy of calculating power of implanted IOL. Lens power calculation can be done by conventional ultrasound biometry and partial coherence laser interferometry (IOL Master). The aim was to compare the accuracy of IOL power calculations using conventional ultrasound biometry and partial coherence laser interferometry.40 eyes were included in this prospective randomized trial. Twenty eyes underwent IOL master and 20 eyes had aplanation ultrasound biometry. There were included only eyes with age-related cataract and postoperative natural visual acuity (VA) 0.7. Visual acuity was performed 6 weeks after cataract surgery. After 6 weeks best natural visual acuity were 0.9 (± 0.1) in IOL-Master group and 0.85 (± 0.15) in ultrasound biometry. The postoperative mean absolute refractive error was 0.75 (± 0.5) D for ultrasound biometry and 0.50 (± 0.50) D for IOL-Master. Optical biometry with the IOL-Master proved to be slightly more accurate than ultrasound biometry for IOL power calculation.

  9. High-frequency ultrasound imaging of tattoo reactions with histopathology as a comparative method. Introduction of preoperative ultrasound diagnostics as a guide to therapeutic intervention.

    Science.gov (United States)

    Carlsen, K Hutton; Tolstrup, J; Serup, J

    2014-08-01

    Tattoo adverse reactions requiring diagnostic evaluation and treatment are becoming more common. The aim of this study was to assess tattoo reactions by 20-MHz ultrasonography referenced to histopathology as a comparative method. A total of 73 individuals with clinical adverse reactions in their tattoos were studied. Punch biopsies for reference histology were available from 58 patients. The Dermascan C(®) of Cortex Technology, Denmark, was employed. Total skin thickness and echo density of the echolucent band in the outer dermis were measured. Biopsy served for diagnosis and for determination of the level of cellular infiltration in the dermis. In every tattoo reaction studied, the skin affected was found thicker compared with regional control of the same individual (mean difference 0.73 mm). A prominent echolucent band of mean thickness 0.89 mm was demonstrated, primarily located in the very outer dermis but propagating to deeper dermal layers parallel to increasing severity of reactions. The thickness of the echolucent band correlated with the thickness of cellular infiltration determined by microscopic examination, R = 0.6412 (P tattoo reactions showed no distinct characteristics by ultrasound, but mainly displayed themselves by their advanced inflammatory component. It is demonstrated for the first time that ultrasound, with histopathology as the comparative method, can quantify the severity of tattoo reactions and non-invasively diagnose the depth of the inflammatory process in the dermis elicited by the microparticulate tattoo pigment, which itself is too minute to be imaged by ultrasound. Preoperative 20-MHz ultrasound scanning is introduced as a potentially useful method to guide therapeutic interventions by surgery and lasers. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. Pre-operative ultrasound identification of thyroiditis helps predict the need for thyroid hormone replacement after thyroid lobectomy.

    Science.gov (United States)

    Morris, Lilah F; Iupe, Isabella M; Edeiken-Monroe, Beth S; Warneke, Carla L; Hansen, Mandy O; Evans, Douglas B; Lee, Jeffrey E; Grubbs, Elizabeth G; Perrier, Nancy D

    2013-01-01

    To evaluate whether pre-operative thyroiditis identified by ultrasound (US) could help predict the need for thyroid hormone replacement (THR) following thyroid lobectomy. Data from patients who underwent thyroid lobectomy in 2006-2011, were not taking THR pre-operatively, and had ≥1 month of follow-up were reviewed retrospectively. THR was prescribed for relatively elevated thyroid-stimulating hormone (TSH) and hypothyroid symptoms. The Kaplan-Meier method was used to estimate the percentage of patients who required THR at 6, 12, 18, and 24 months postoperatively, and Cox proportional hazards regression models were used to evaluate prognostic factors for requiring post-thyroid lobectomy THR. During follow-up, 45 of 98 patients required THR. Median follow-up among patients not requiring THR was 11.6 months (range, 1.2 to 51.3 months). Six months after thyroid lobectomy, 22% of patients were taking THR (95% confidence interval [CI], 15-32%); the proportion increased to 46% at 12 months (95% CI, 36-57%) and 55% at 18 months (95% CI, 43-67%). On univariate analysis, significant prognostic factors for postoperative THR included a pre-operative TSH level >2.5 μ international units [IU]/mL (hazard ratio [HR], 2.8; 95% CI, 1.4-5.5; P = .004) and pathology-identified thyroiditis (HR, 2.4; 95% CI, 1.3-4.3; P = .005). Patients with both pre-operative TSH >2.5 μIU/mL and US-identified thyroiditis had a 5.8-fold increased risk of requiring postoperative THR (95% CI, 2.4-13.9; P2.5 μIU/mL significantly increases the risk of requiring THR after thyroid lobectomy. Thyroiditis can add to that prediction and guide pre-operative patient counseling and surgical decision making. US-identified thyroiditis should be reported and post-thyroid lobectomy patients followed long-term (≥18 months).

  11. Isolated tubal torsion: Successful preoperative diagnosis of five cases using ultrasound and management with laparoscopy

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    Erdem Fadıloğlu

    2017-09-01

    Full Text Available Our aim was to evaluate the presentation and diagnostic evaluation of patients with isolated tubal torsion and to evaluate the surgical approach to these patients. We also aimed to define the ultrasonographic diagnostic criteria. Five patients with isolated tubal torsion who were admitted to our gynecology department between January 2014 and January 2017 were evaluated and included in this study. All cases were diagnosed through ultrasonographic imaging alone. The preoperative findings of the patients were similar to those described in the literature. No further imaging modality was used for diagnosis and all patients were managed with laparoscopy. The clinical findings and ultrasonographic findings were consistent with literature. It may be difficult to preoperatively diagnose isolated tubal torsion, which is a rare clinical entity. Evaluation of these patients by an experienced sonographer and knowledge of the ultrasonographic findings of isolated tubal torsion may have vital preventive measures.

  12. Standardized Duplex Ultrasound-Based Protocol for Early Diagnosis of Transplant Renal Artery Stenosis: Results of a Single-Institution Retrospective Cohort Study

    Directory of Open Access Journals (Sweden)

    Vincenzo Li Marzi

    2018-01-01

    Full Text Available Transplant renal artery stenosis (TRAS is the most frequent vascular complication after kidney transplantation (KT and has been associated with potentially reversible refractory hypertension, graft dysfunction, and reduced patient survival. The aim of the study is to describe the outcomes of a standardized Duplex Ultrasound- (DU- based screening protocol for early diagnosis of TRAS and for selection of patients potentially requiring endovascular intervention. We retrospectively reviewed our prospectively collected database of KT from January 1998 to select patients diagnosed with TRAS. The follow-up protocol was based on a risk-adapted, dynamic subdivision of eligible KT patients in different risk categories (RC with different protocol strategies (PS. Of 598 patients included in the study, 52 (9% patients had hemodynamically significant TRAS and underwent percutaneous angioplasty (PTA and stent placement. Technical and clinical success rates were 97% and 90%, respectively. 7 cases of restenosis were recorded at follow-up and treated with re-PTA plus stenting. Both DU imaging and clinical parameters improved after stent placement. Prospective high-quality studies are needed to test the efficacy and safety of our protocol in larger series. Accurate trial design and standardized reporting of patient outcomes will be key to address the current clinical needs.

  13. Test characteristics of high-resolution ultrasound in the preoperative assessment of margins of basal cell and squamous cell carcinoma in patients undergoing Mohs micrographic surgery.

    Science.gov (United States)

    Jambusaria-Pahlajani, Anokhi; Schmults, Chrysalyne D; Miller, Christopher J; Shin, Daniel; Williams, Jennifer; Kurd, Shanu K; Gelfand, Joel M

    2009-01-01

    Noninvasive techniques to assess subclinical spread of nonmelanoma skin cancer (NMSC) may improve surgical precision. High-resolution ultrasound has shown promise in evaluating the extent of NMSC. To determine the accuracy of high-resolution ultrasound to assess the margins of basal cell (BCC) and squamous cell carcinomas (SCC) before Mohs micrographic surgery (MMS). We enrolled 100 patients with invasive SCC or BCC. Before the first stage of MMS, a Mohs surgeon delineated the intended surgical margin. Subsequently, a trained ultrasound technologist independently evaluated disease extent using the EPISCAN I-200 to evaluate tumor extent beyond this margin. The accuracy of high-resolution ultrasound was subsequently tested by comparison with pathology from frozen sections. The test characteristics of the high-resolution ultrasound were sensitivity=32%, specificity=88%, positive predictive value=47%, and negative predictive value=79%. Subgroup analyses demonstrated better test characteristics for tumors larger than the median (area>1.74 cm(2)). Qualitative analyses showed that high-resolution ultrasound was less likely to identify extension from tumors with subtle areas of extension, such as small foci of dermal invasion from infiltrative SCC and micronodular BCC. High-resolution ultrasound requires additional refinements to improve the preoperative determination of tumor extent before surgical treatment of NMSC.

  14. Preoperative estimation of the pathological breast tumour size by physical examination, mammography and ultrasound: a prospective study on 105 invasive tumours

    International Nuclear Information System (INIS)

    Bosch, Anne M.; Kessels, Alfons G.H.; Beets, Geerard L.; Rupa, Jan D.; Koster, Dick; Engelshoven, Jos M.A. van; Meyenfeldt, Maarten F. von

    2003-01-01

    Objective: The clinical breast tumour size can be assessed preoperatively by physical examination, mammography and ultrasound. At present it is not clear which modality correlates best with the histological invasive breast tumour size. This prospective study aims to determine the most accurate clinical method (physical examination, mammography or ultrasound) to predict the histological invasive tumour size preoperatively. Methods and patients: Between October 1999 and August 2000, 96 women with 105 invasive malignant breast tumours were included in this study. All patients underwent excision and the tumour size was measured on histology. Tumour size was measured by all three modalities in 73 cases. Results were evaluated by calculating correlation coefficients. The examination modalities presenting the best estimation of the pathological tumour size were used in a stepwise linear regression analysis to construct a formula predicting the pathological tumour size from the result of the various diagnostic modalities. Results: The correlation coefficient between ultrasound and pathological size (r=0.68) was significantly better than the correlations between physical examination and pathological size (r=0.42) and mammographic and pathological size (r=0.44). Physical examination overestimates and ultrasound underestimates breast tumour classification. The most accurate prediction formula was: Pathological tumour size (mm) equals sonographic tumour size (mm)+3 mm. Conclusion: When comparing physical examination, mammography and ultrasound for the prediction of the pathological size of a malignant breast tumour, ultrasound is the best predictor. The ensuing regression formula determines pathological size as tumour size by ultrasound+3 mm. However, with the wide 95% confidence interval of ±11 mm, it remains difficult to predict the exact pathological size for an individual invasive breast tumour. A small deviation in millimetres of the tumour size could lead to a change in

  15. Ultrasound guided fine needle aspiration cytology versus core biopsy in the preoperative assessment of non-palpable breast lesions

    International Nuclear Information System (INIS)

    Ahmed, M.E.; Ahmad, I.

    2010-01-01

    Background: Breast screening is a method of detecting breast cancer at a very early stage. Most of the lesions detected by screening are not malignant. Objective of this study was to compare ultrasound guided fine needle aspiration cytology and core biopsy in the preoperative assessment of non-palpable breast lesions. Methods: The study was conducted prospectively at Department of Radiology, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Pakistan from March 2004 to February 2005. All the patients underwent fine needle aspiration cytology and core biopsy. Later on, all of them had excision biopsy/ mastectomy. Prospectively 80 patients were studied; information was collected on a specifically designed form according to inclusion criteria. The patient age, sex, medical record number and side of lesion were recorded. Clinical history of duration of lump was also taken. Informed consent was obtained. Results: The age of patients were ranges from 20-71 years, with mean of 44.31+- 11.002 and the maximum number of patients 28 (35.3%) was between the ages 50 - 59 years. The sensitivity of FNAC was 92.85%, while the specificity of was 90% and the accuracy rate was 92.1%. The sensitivity of core biopsy was 94.64%, specificity 91.30% and accuracy rate was 94.87%. Conclusion: Fine Needle Aspiration has been found to be an extremely useful method for the diagnosis of lumps of breast. The accuracy and the sensitivity of diagnosis on fine needle aspiration cytology were high. (author)

  16. Efficacy of patient selection strategies for carotid endarterectomy by contrast-enhanced MRA on a 1 T machine and duplex ultrasound in a regional hospital

    International Nuclear Information System (INIS)

    Korteweg, M.A.; Kerkhoff, H.; Bakker, J.; Elgersma, O.E.H.

    2008-01-01

    Aim: To investigate whether contrast-enhanced magnetic resonance angiography (CE-MRA) and duplex ultrasound (DUS) could replace digital subtraction angiography (DSA) for diagnosing internal carotid artery (ICA) stenosis in regional centres with less specialized technicians and equipment, such as a 1 Tesla MRI machine. Materials and methods: Sixty-six consecutive, symptomatic patients with ICA stenosis, as evidenced using DSA, were included. In the first 34 patients DUS was validated and cut-off criteria were established. Data were analysed by receiver operating characteristic curve and logistic regression. Two observers analysed the DUS and CE-MRA results of 32 patients. Stenoses were categorized in accordance with North American Symptomatic Endarterectomy Trial (NASCET) measurement criteria. Results: Peak systolic velocity (PSV) in the ICA was defined as a better parameter for defining stenosis than end diastolic velocity and the PSV ICA:common carotid artery ratio. The optimal PSV threshold was 230 cm/s. Four ICAs were not interpretable on DUS, and one on CE-MRA. Two patients did not undergo CE-MRA. The sensitivities and specificities were calculated: for DUS these were 100% and 68% respectively; for observer 1 on CE-MRA these were 93% and 89%, respectively; for observer 2 these were 92% and 87%, respectively. The sensitivity and specificity for combined DUS/CE-MRA were 100% and 85%, respectively. Seventy-eight percent of CE-MRA and DUS correlated. The weighted Kappa for CE-MRA and DSA were 0.8 and 0.9, respectively. Conclusion: DUS and CE-MRA are effective non-invasive methods for selecting patients with ICA stenosis for carotid endarterectomy in non-specialized centres using a 1 T machine. The present results suggest that no referrals to more specialized centres for non-invasive diagnostic work-up for carotid artery stenoses will be necessary

  17. Comparison between angiographic and arterial duplex ultrasound assessment of tibial arteries in patients with peripheral arterial disease: on behalf of the Joint Endovascular and Non-Invasive Assessment of LImb Perfusion (JENALI) Group.

    Science.gov (United States)

    Mustapha, Jihad A; Saab, Fadi; Diaz-Sandoval, Larry; Karenko, Barbara; McGoff, Theresa; Heaney, Carmen; Sevensma, Matthew

    2013-11-01

    Endovascular treatment of peripheral arterial disease (PAD) involving the tibial arteries is becoming an increasingly important part of revascularization. The current anatomical description of vessel patency in tibial arteries does not contribute effectively to therapeutic strategies. The Joint Endovascular and Non-Invasive Assessment of Limb Perfusion (JENALI) score, is a novel scoring system developed to further assess patency of tibial arteries, via both angiography and arterial duplex ultrasonography. A comparison was made between the JENALI score obtained by ultrasound and by angiography. Angiography is currently considered the gold standard of tibial artery imaging. This prospective single-center study involved 49 patients undergoing peripheral angiography for evaluation of PAD, between November 2011 and November 2012. All patients underwent a detailed ultrasound assessment of the tibial arteries ± 7 days from diagnostic angiography. Eligible patients had a Rutherford score ≥ III or abnormal ankle-brachial index values. Angiography and ultrasound were evaluated in a blinded fashion. Average age of patients was 69.8 years. A total of 846 segments were assessed by both angiography and ultrasound. We found that 648 segments (76.6%) were deemed to be patent by angiography compared to 723 (85.5%) by ultrasound. Critical limb ischemia (CLI; Rutherford score ≥ 4) was described in 26 patients (53%). Average JENALI score for the right lower extremity was 7.0 by angiogram vs 7.7 by ultrasound. The average JENALI score of the left leg was 6.7 by angiogram vs 7.7 by ultrasound. A total of 94 lower extremities were assigned a JENALI score. Ultrasound was accurate in detecting tibial artery patency or occlusion in 80% of segments. The overall sensitivity/specificity of ultrasound detecting tibial artery patency was calculated at 93% and 40% (P<.05), respectively. Detection of patency via ultrasound was highest for the anterior tibial artery and the lowest for the

  18. Preoperative ultrasound staging of the axilla make's peroperative examination of the sentinel node redundant in breast cancer: saving tissue, time and money.

    Science.gov (United States)

    Van Berckelaer, Christophe; Huizing, Manon; Van Goethem, Mireille; Vervaecke, Andrew; Papadimitriou, Konstantinos; Verslegers, Inge; Trinh, Bich X; Van Dam, Peter; Altintas, Sevilay; Van den Wyngaert, Tim; Huyghe, Ivan; Siozopoulou, Vasiliki; Tjalma, Wiebren A A

    2016-11-01

    To evaluate the role of preoperative axillary staging with ultrasound (US) and fine needle aspiration cytology (FNAC). Can we avoid intraoperative sentinel lymph node (SLN) examination, with an acceptable revision rate by preoperative staging? This study is based on the retrospective data of 336 patients that underwent US evaluation of the axilla as part of their staging. A FNAC biopsy was performed when abnormal lymph nodes were visualized. Patients with normal appearing nodes on US or a benign diagnostic biopsy had removal of the SLNs without intraoperative pathological examination. We calculated the sensitivity, specificity and accuracy of US/FNAC in predicting the necessity of an axillary lymphadenectomy. Subsequently we looked at the total cost and the operating time of 3 models. Model A is our study protocol. Model B is a theoretical protocol based on the findings of the Z0011 trial with only clinical preoperative staging and in Model C preoperative staging and intraoperative pathological examination were both theoretically done. sentinel node, staging, ultrasound, preoperative axillary staging, FNAC, axilla RESULTS: The sensitivity, specificity and accuracy are respectively 0.75 (0.66-0.82), 1.00 (0.99-1.00) and 0.92 (0.88-0.94). Only 26 out of 317 (8.2%) patients that successfully underwent staging needed a revision. The total cost of Model A was 1.58% cheaper than Model C and resulted in a decrease in operation time by 9,46%. The benefits compared with Model B were much smaller. Preoperative US/FNAC staging of the axillary lymph nodes can avoid intraoperative examination of the sentinel node with an acceptable revision rate. It saves tissue, reduces operating time and decreases healthcare costs in general. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  19. Ultrasound elastography as an adjuvant to conventional ultrasound in the preoperative assessment of axillary lymph nodes in suspected breast cancer: A pilot study

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    Taylor, K., E-mail: kathryn.taylor@addenbrookes.nhs.uk [Department of Radiology, Cambridge Breast Unit, Cambridge University Hospitals NHS Foundation Trust, Cambridge (United Kingdom); O' Keeffe, S.; Britton, P.D.; Wallis, M.G. [Department of Radiology, Cambridge Breast Unit, Cambridge University Hospitals NHS Foundation Trust, Cambridge (United Kingdom); Treece, G.M.; Housden, J. [Department of Engineering, University of Cambridge, Cambridge (United Kingdom); Parashar, D.; Bond, S. [Cambridge Cancer Trials Centre, Department of Oncology, University of Cambridge, Addenbrookes Hospital, Cambridge (United Kingdom); Cambridge Hub in Trials Methodology Research, MRC Biostatics Unit, University Forvie Site, Cambridge (United Kingdom); Sinnatamby, R. [Department of Radiology, Cambridge Breast Unit, Cambridge University Hospitals NHS Foundation Trust, Cambridge (United Kingdom)

    2011-11-15

    Aims: To compare the performance of ultrasound elastography with conventional ultrasound in the assessment of axillary lymph nodes in suspected breast cancer and whether ultrasound elastography as an adjunct to conventional ultrasound can increase the sensitivity of conventional ultrasound used alone. Materials and methods: Fifty symptomatic women with a sonographic suspicion for breast cancer underwent ultrasound elastography of the ipsilateral axilla concurrent with conventional ultrasound being performed as part of triple assessment. Elastograms were visually scored, strain measurements calculated and node area and perimeter measurements taken. Theoretical biopsy cut points were selected. The sensitivity, specificity, positive predictive value (PPV), and negative predictive values (NPV) were calculated and receiver operating characteristic (ROC) analysis was performed and compared for elastograms and conventional ultrasound images with surgical histology as the reference standard. Results: The mean age of the women was 57 years. Twenty-nine out of 50 of the nodes were histologically negative on surgical histology and 21 were positive. The sensitivity, specificity, PPV, and NPV for conventional ultrasound were 76, 78, 70, and 81%, respectively; 90, 86, 83, and 93%, respectively, for visual ultrasound elastography; and for strain scoring, 100, 48, 58 and 100%, respectively. There was no significant difference between any of the node measurements Conclusions: Initial experience with ultrasound elastography of axillary lymph nodes, showed that it is more sensitive than conventional ultrasound in detecting abnormal nodes in the axilla in cases of suspected breast cancer. The specificity remained acceptable and ultrasound elastography used as an adjunct to conventional ultrasound has the potential to improve the performance of conventional ultrasound alone.

  20. Comparison of Oral Contrast-Enhanced Transabdominal Ultrasound Imaging With Transverse Contrast-Enhanced Computed Tomography in Preoperative Tumor Staging of Advanced Gastric Carcinoma.

    Science.gov (United States)

    He, Xuemei; Sun, Jing; Huang, Xiaoling; Zeng, Chun; Ge, Yinggang; Zhang, Jun; Wu, Jingxian

    2017-12-01

    This study assessed the diagnostic performance of transabdominal oral contrast-enhanced ultrasound (US) imaging for preoperative tumor staging of advanced gastric carcinoma by comparing it with transverse contrast-enhanced computed tomography (CT). This retrospective study included 42 patients with advanced gastric cancer who underwent laparoscopy, radical surgery, or palliative surgery because of serious complications and had a body mass index of less than 25 kg/m 2 . A cereal-based oral contrast agent was used for transabdominal oral contrast-enhanced US. Retrospective analyses were conducted using preoperative tumor staging data acquired by either transabdominal oral contrast-enhanced US or transverse contrast-enhanced CT. Both contrast-enhanced US and contrast-enhanced CT examinations were reviewed by 2 experienced radiologists independently for preoperative tumor staging according to the seventh edition of the TNM classification. The accuracy, sensitivity, and specificity were calculated by comparing the results of contrast-enhanced US and contrast-enhanced CT with pathologic findings. The overall accuracies of the imaging modalities were compared by the McNemar test. No significant difference was noted in the overall accuracy of transabdominal oral contrast-enhanced US (86% [36 of 42]) and transverse contrast-enhanced CT (83% [35 of 42] P > .999). For stage T2 to T4 gastric cancer, the accuracies of transabdominal oral contrast-enhanced US were 88%, 86%, and 98%, respectively, and those of transverse contrast-enhanced CT were 93%, 83%, and 90%. The overall accuracy of transabdominal oral contrast-enhanced US was comparable with that of transverse contrast-enhanced CT for preoperative tumor staging of advanced gastric cancer. © 2017 by the American Institute of Ultrasound in Medicine.

  1. Ultrasound

    Science.gov (United States)

    Ultrasound is a useful procedure for monitoring the baby's development in the uterus. Ultrasound uses inaudible sound waves to produce a two-dimensional image of the baby while inside the mother's ...

  2. Position tracking of moving liver lesion based on real-time registration between 2D ultrasound and 3D preoperative images

    International Nuclear Information System (INIS)

    Weon, Chijun; Hyun Nam, Woo; Lee, Duhgoon; Ra, Jong Beom; Lee, Jae Young

    2015-01-01

    Purpose: Registration between 2D ultrasound (US) and 3D preoperative magnetic resonance (MR) (or computed tomography, CT) images has been studied recently for US-guided intervention. However, the existing techniques have some limits, either in the registration speed or the performance. The purpose of this work is to develop a real-time and fully automatic registration system between two intermodal images of the liver, and subsequently an indirect lesion positioning/tracking algorithm based on the registration result, for image-guided interventions. Methods: The proposed position tracking system consists of three stages. In the preoperative stage, the authors acquire several 3D preoperative MR (or CT) images at different respiratory phases. Based on the transformations obtained from nonrigid registration of the acquired 3D images, they then generate a 4D preoperative image along the respiratory phase. In the intraoperative preparatory stage, they properly attach a 3D US transducer to the patient’s body and fix its pose using a holding mechanism. They then acquire a couple of respiratory-controlled 3D US images. Via the rigid registration of these US images to the 3D preoperative images in the 4D image, the pose information of the fixed-pose 3D US transducer is determined with respect to the preoperative image coordinates. As feature(s) to use for the rigid registration, they may choose either internal liver vessels or the inferior vena cava. Since the latter is especially useful in patients with a diffuse liver disease, the authors newly propose using it. In the intraoperative real-time stage, they acquire 2D US images in real-time from the fixed-pose transducer. For each US image, they select candidates for its corresponding 2D preoperative slice from the 4D preoperative MR (or CT) image, based on the predetermined pose information of the transducer. The correct corresponding image is then found among those candidates via real-time 2D registration based on a

  3. Test characteristics of high frequency ultrasound in the pre-operative assessment of margins of basal cell and squamous cell carcinoma in patients undergoing Mohs micrographic surgery

    Science.gov (United States)

    Jambusaria-Pahlajani, Anokhi; Schmults, Chrysalyne D.; Miller, Christopher J.; Shin, Daniel; Williams, Jennifer; Kurd, Shanu K; Gelfand, Joel M.

    2015-01-01

    Background Non-invasive techniques to assess subclinical spread of non-melanoma skin cancer (NMSC) may improve surgical precision. High frequency ultrasound (HIFU) has shown promise to evaluate the extent of NMSC. Objective To determine the accuracy of HIFU to assess the margins of basal cell (BCC) and squamous cell carcinomas (SCC) prior to Mohs micrographic surgery (MMS). Methods We enrolled 100 patients with invasive SCC or BCC. Prior to the first stage of MMS, a Mohs surgeon delineated the intended surgical margin. Subsequently, a trained ultrasound technologist independently evaluated disease extent using the EPISCAN I-200 to evaluate tumor extent beyond this margin. The accuracy of HIFU was subsequently tested by comparison to pathology from frozen sections. Results The test characteristics of the ultrasound were sensitivity= 32%, specificity= 88%, positive predictive value= 47%, and negative predictive value=79%. Subgroup analyses demonstrated improved test characteristics for tumors larger than the median (area >1.74 cm2). Qualitative analyses showed that HIFU was less likely to identify extension from tumors with subtle areas of extension, such as small foci of dermal invasion from infiltrative SCC and micronodular BCC. Conclusions HIFU requires additional refinements to improve the preoperative determination of tumor extent prior to surgical treatment of NMSC. PMID:19018815

  4. Clinical utility of routine pre-operative axillary ultrasound and fine needle aspiration cytology in patient selection for sentinel lymph node biopsy.

    Science.gov (United States)

    Rattay, T; Muttalib, M; Khalifa, E; Duncan, A; Parker, S J

    2012-04-01

    In patients with operable breast cancer, pre-operative evaluation of the axilla may be of use in the selection of appropriate axillary surgery. Pre-operative axillary ultrasound (US) and fine needle aspiration cytology (FNAC) assessments have become routine practice in many breast units, although the evidence base is still gathering. This study assessed the clinical utility of US+/-FNAC in patient selection for either axillary node clearance (ANC) or sentinel lymph node biopsy (SLNB) in patients undergoing surgery for operable breast cancer. Over a two-year period, 348 patients with a clinically negative axilla underwent axillary US. 67 patients with suspicious nodes on US also underwent FNAC. The sensitivity and specificity of axillary investigations to determine nodal involvement were 56% (confidence interval: 47-64%) and 90% (84-93%) for US alone, and 76% (61-87%) and 100% (65-100%) for FNAC combined with US, respectively. With a positive US, the post-test probability was 78%. A negative US carried a post-test probability of 25%. When FNAC was positive, the post-test probability was greater than unity. A negative FNAC yielded a post-test probability of 52%. All patients with positive FNAC and most patients with suspicious US were listed for axillary node clearance (ANC) after consideration at the multi-disciplinary team (MDT) meeting. With pre-operative axillary US+/-FNAC, 20% of patients were saved a potential second axillary procedure, facilitating a reduction in the overall re-operation rate to 12%. In this study, a positive pre-operative US+/-FNAC directs patients towards ANC. When the result is negative, other clinico-pathological factors need to be taken into account in the selection of the appropriate axillary procedure. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Preoperative prediction of lymph node metastasis and deep stromal invasion in women with invasive cervical cancer: prospective multicenter study using 2D and 3D ultrasound.

    Science.gov (United States)

    Pálsdóttir, K; Fischerova, D; Franchi, D; Testa, A; Di Legge, A; Epstein, E

    2015-04-01

    To determine how various objective two-dimensional (2D) and three-dimensional (3D) ultrasound parameters allow prediction of deep stromal tumor invasion and lymph node involvement, in comparison to subjective ultrasound assessment, in women scheduled for surgery for cervical cancer. This was a prospective multicenter trial including 104 women with cervical cancer at FIGO Stages IA2-IIB, verified histologically. Patients scheduled for surgery underwent a preoperative ultrasound examination. The value of various 2D (size, color score) and 3D (volume, vascular indices) ultrasound parameters was compared to that of subjective assessment in the prediction of deep stromal tumor invasion and lymph node involvement. Histology obtained from radical hysterectomy or trachelectomy and pelvic lymphadenectomy was considered as the gold standard for assessment. All women underwent pelvic lymphadenectomy, with 99 (95%) undergoing subsequent radical surgery; five underwent only pelvic lymphadenectomy because of the presence of a positive sentinel lymph node. Women with deep stromal invasion or lymph node involvement had significantly larger tumors (diameter and volume) but there was no correlation with vascular indices measured on 3D ultrasound. Subjective evaluation was superior (AUC, 0.93; sensitivity, 90.5%; specificity, 97.2%) in the prediction of deep stromal invasion when compared to any objective measurement technique, with maximal tumor diameter at 20.5-mm cut-off (AUC, 0.83; sensitivity, 90.5%; specificity, 61.1%) and 3D tumor volume at 9.1-mm(3) cut-off (AUC, 0.85; sensitivity, 79.4%; specificity, 83.3%) providing the best performance among the objective parameters. Both subjective assessment and objective measurements were poorly predictive of lymph node involvement. In women with cervical cancer, subjective ultrasound evaluation allowed better prediction of deep stromal invasion than did objective measurements; however, neither subjective evaluation nor objective

  6. Predicting erectile dysfunction following surgical correction of Peyronie's disease without inflatable penile prosthesis placement: vascular assessment and preoperative risk factors.

    Science.gov (United States)

    Taylor, Frederick L; Abern, Michael R; Levine, Laurence A

    2012-01-01

    Surgical therapy remains the gold standard treatment for Peyronie's Disease (PD). Surgical options include plication, grafting, and placement of inflatable penile prosthesis (IPP). Postoperative erectile dysfunction (ED) is a potential complication for PD surgery without IPP. We present our large series follow-up to evaluate preoperative risk factors for postoperative ED. The aim of this study is to evaluate preoperative risk factors for the development of ED following surgical correction of PD taking into account the degree of curvature, graft size, surgical approach, hypertension, hyperlipidemia, diabetes, smoking history, preoperative use of phosphodiesterase 5 inhibitors (PDE5), and preoperative duplex ultrasound findings including peak systolic and end diastolic velocities and resistive index. We identified 218 men undergoing either tunica albuginea plication (TAP) or partial plaque excision with pericardial grafting for PD following a previously published algorithm between November 1992 and April 2007. Preoperative and postoperative erectile function, curvature characteristics, presence of vascular risk factors, and duplex ultrasound findings were available on 109 patients. Our primary outcome measure is the development of ED after surgery for PD. Ten percent of TAP and 21% of plaque excision with grafting patients developed postoperative ED. Neither curve direction (P = 0.76), graft area (P = 0.78), surgical approach (P = 0.12), chronic hypertension (P = 0.51), hyperlipidemia (P = 0.87), diabetes (P = 0.69), nor smoking history (P = 0.99) were significant predictors of postoperative ED. No combination of risk factors was found to be predictive of postoperative ED. Preoperative use of PDE5 was not a significant predictor of postoperative ED (P = 0.33). Neither peak systolic, end diastolic, nor resistive index were significant predictors of ED (P = 0.28, 0.28, and 0.25, respectively). This long-term follow-up of a large published series suggests that neither

  7. Effects of preoperative ultrasound-guided transversus abdominis plane block on pain after laparoscopic surgery for colorectal cancer: a double-blind randomized controlled trial.

    Science.gov (United States)

    Oh, Tak Kyu; Yim, Jiyeon; Kim, Jaehyun; Eom, Woosik; Lee, Soon Ae; Park, Sung Chan; Oh, Jae Hwan; Park, Ji Won; Park, Boram; Kim, Dae Hyun

    2017-01-01

    Although laparoscopic colorectal surgery decreases postoperative pain and facilitates a speedier recovery compared with laparotomy, postoperative pain at trocar insertion sites remains a clinical concern. The objective of this study was to assess the effects of a preoperative ultrasound-guided transversus abdominis plane (TAP) block on pain after laparoscopic surgery for colorectal cancer. In total, 58 patients scheduled to undergo laparoscopic surgery following a diagnosis of colorectal cancer were included in this study. The patients were randomized into TAP and control groups; the TAP group patients received a preoperative ultrasound-guided bilateral TAP block with 0.5 mL/kg of 0.25 % bupivacaine, while the control patients received the block with an equal amount of saline. Pain on coughing and at rest was assessed during postanesthetic recovery (PAR; 1 h after surgery) and on postoperative days (PODs) 1 (24 h), 2 (48 h), and 3 (72 h) by an investigator blinded to group allocations using the numeric rating scale (NRS). The primary outcome was pain on coughing on postoperative day (POD) 1. Fifty-five patients were included in the final analysis, including 28 in the TAP and 27 in the control groups. The pain intensity on coughing and at rest during PAR and on PODs 1, 2, and 3 showed no significant differences between groups. Furthermore, there was no significant difference in postoperative opioid consumption, sedation scores, nausea scores at the four time points, complication rates, and length of hospital stay between groups. In colorectal cancer patients undergoing laparoscopic colorectal surgery, a TAP block did not offer enough benefit for clinical efficacy in terms of postoperative pain or analgesic consumption.

  8. Ultrasound

    Science.gov (United States)

    ... completed. Young children may need additional preparation. When scheduling an ultrasound for yourself or your child, ask ... of Privacy Practices Notice of Nondiscrimination Manage Cookies Advertising Mayo Clinic is a not-for-profit organization ...

  9. Ultrasound

    Science.gov (United States)

    ... reflect off body structures. A computer receives the waves and uses them to create a picture. Unlike with an x-ray or CT scan, this test does not use ionizing radiation. The test is done in the ultrasound ...

  10. Role of axillary lymph node ultra-sound and large core biopsy in the preoperative assessment of patients selected for sentinel node biopsy

    International Nuclear Information System (INIS)

    Nori, Jacopo; Boeri, Cecilia; Vanzi, Ermanno; Nori Bufalini, Filippo; Masi, Andrea; Bazzocchi, Massimo; Londero, Viviana; Mangialavori, Giuseppe; Distante, Vito; Simoncini, Roberta

    2005-01-01

    Purpose: To aim of this study was to evaluate the diagnostic accuracy of axillary lymph node sonography, if necessary in collaboration with US-guided large core biopsy, in the preoperative evaluation of breast cancer patients scheduled for quadrantectomy and sentinel lymph node excision. Materials and methods: From July 2001 to December 2002, we evaluated 117 breast cancer patients with ultrasound and, where indicated, FNAB. Breast lesions has diameters between 4 and 26 mm (mean diameter 11 mm). Fifteen (13%) of the 117 patients were excluded from the series as they did not found fulfil the criteria for preliminary sonography of the axilla: in 9 patients fewer than 4 nodes were detected and in 6 patients the breast lesions were intraoperatively found to be benign. Eleven patients (10.7%) with sonographically suspicious axillary nodes were sampled by US-guided core biopsy using a 14 or 16 Gauge Tru-Cut needle. Results: The ultrasound study aims to evaluate the dimensions and morphology of the breast lesion as well as detect and assess at least 4 axillary nodes. These were evaluated for hilar and cortical thickening and radio between the sinus diameter and the total longitudinal diameter. Lymph nodes with hilar diameters equal to or greater than 50% of the longitudinal diameter were considered normal. Of the 102 patients evaluated, 77 (75.7%) had normal axillary nodes according to the US criteria adopted. Negativity was confirmed by histology in 56 cases (72.7%, true negative); 21 (27.3%, false negative) were found to be positive, in contrast with the sonographic appearance. The false negative cases were due to lymph node micrometastasis which probably did not cause morphologic alterations perceptible at ultrasound. The remaining 25 patients (24.5%) had axillary lymph nodes classified as suspicious. In 13 cases of (52%, true positive) there was agreement with histology, whereas in 12 cases (48%, false positive) the US suspicion was not confirmed at surgery. The most

  11. Duplex kidney: not just a drooping lily.

    Science.gov (United States)

    Doery, Ashlea J; Ang, Eileen; Ditchfield, Michael R

    2015-04-01

    Duplex kidneys are common, mostly asymptomatic and of no clinical significance. However, they can be associated with significant pathology, often with long-term morbidity. There is minimal literature on the review of the duplex kidney, its associated anomalies and complications. The purpose of this paper is to review our experience of imaging the spectrum of abnormalities associated with duplex kidneys in the paediatric population and correlate this with contemporary literature. A retrospective review of the radiology database in a tertiary paediatric centre was performed. A word search of the Radiology Information System for 'duplex' of patients under the age of 16 was undertaken and limited to studies performed between 2006 and 2013. Two hundred seventy-four patients were identified (age range 0-16, median 3 years, gender 59.9% female) who had 836 studies: ultrasound 598/836 (71.6%), nuclear medicine 180/836 (21.5%), micturating cystourethrogram 52/836 (6.2%), MRI 5/836 (duplex and no complication (151/274 = 55.1%), upper moiety obstruction, lower moiety reflux/scarring, multicystic dysplastic kidney, abnormal ureteric insertion and other pathology. Duplex kidneys are common and often not clinically significant. However, this study demonstrates almost 50% of paediatric patients investigated for duplex kidneys had complications requiring treatment. The most common complications were upper moiety obstruction associated with a ureterocele and lower moiety vesicoureteric reflux. Ultrasound was the most common modality for early detection of these complications. © 2015 The Royal Australian and New Zealand College of Radiologists.

  12. Duplex Ultrasonography Has Limited Utility in Detection of Postoperative DVT After Primary Total Joint Arthroplasty.

    Science.gov (United States)

    Vira, Shaleen; Ramme, Austin J; Alaia, Michael J; Steiger, David; Vigdorchik, Jonathan M; Jaffe, Frederick

    2016-07-01

    Duplex ultrasound is routinely used to evaluate suspected deep venous thrombosis after total joint arthroplasty. When there is a clinical suspicion for a pulmonary embolism, a chest angiogram (chest CTA) is concomitantly obtained. Two questions were addressed: First, for the population of patients who receive duplex ultrasound after total joint arthroplasty, what is the rate of positive results? Second, for these patients, how many of these also undergo chest CTA for clinical suspicion of pulmonary embolus and how many of these tests are positive? Furthermore, what is the correlation between duplex ultrasound results and chest CTA results? A retrospective chart review was conducted of total joint replacement patients in 2011 at a single institution. Inclusion criteria were adult patients who underwent a postoperative duplex ultrasonography for clinical suspicion of deep venous thrombosis (DVT). Demographic data, result of duplex scan, clinical indications for obtaining the duplex scan, and DVT prophylaxis used were recorded. Additionally, if a chest CTA was obtained for clinical suspicion for pulmonary embolus, results and clinical indication for obtaining the test were recorded. The rate of positive results for duplex ultrasonography and chest CTA was computed and correlated based on clinical indications. Two hundred ninety-five patients underwent duplex ultrasonography of which only 0.7% were positive for a DVT. One hundred three patients underwent a chest CTA for clinical suspicion of a pulmonary embolism (PE) of which 26 revealed a pulmonary embolus, none of which had a positive duplex ultrasound. Postoperative duplex scans have a low rate of positive results. A substantial number of patients with negative duplex results subsequently underwent chest CTA for clinical suspicion for which a pulmonary embolus was found, presumably resulting from a DVT despite negative duplex ultrasound result. A negative duplex ultrasonography should not rule out the presence of a

  13. Preoperative differentiation between T1a and ≥T1b gallbladder cancer: combined interpretation of high-resolution ultrasound and multidetector-row computed tomography

    International Nuclear Information System (INIS)

    Joo, Ijin; Baek, Jee Hyun; Kim, Jung Hoon; Han, Joon Koo; Choi, Byung Ihn; Lee, Jae Young; Park, Hee Sun

    2014-01-01

    To determine the diagnostic value of combined interpretation of high-resolution ultrasound (HRUS) and multidetector-row computed tomography (MDCT) for preoperative differentiation between T1a and ≥T1b gallbladder (GB) cancer. Eighty-seven patients with pathologically confirmed GB cancers (T1a, n = 15; ≥T1b, n = 72), who preoperatively underwent both HRUS and MDCT, were included in this retrospective study. Two reviewers independently determined the T-stages of the GB cancers on HRUS and MDCT using a five-point confidence scale (5, definitely T1a; 1, definitely ≥T1b). For individual modality interpretation, the lesions with scores ≥4 were classified as T1a, and, for combined modality interpretation, the lesions with all scores ≥4 in both modalities were classified as T1a. The McNemar test was used to compare diagnostic performance. The diagnostic accuracy of differentiation between T1a and ≥T1b GB cancer was higher using combined interpretation (90.8 % and 88.5 % for reviewers 1 and 2, respectively) than individual interpretation of HRUS (82.8 % and 83.9 %) or MDCT (74.7 % and 82.8 %) (P < 0.05, reviewer 1). Combined interpretations demonstrated 100 % specificity for both reviewers, which was significantly higher than individual interpretations (P < 0.05, both reviewers). Combined HRUS and MDCT interpretation may improve the diagnostic accuracy and specificity for differentiating between T1a and ≥T1b GB cancers. circle Differentiating between T1a and ≥T1b gallbladder cancer can help surgical planning. (orig.)

  14. Preoperative planning of calcium deposit removal in calcifying tendinitis of the rotator cuff - possible contribution of computed tomography, ultrasound and conventional X-Ray.

    Science.gov (United States)

    Izadpanah, Kaywan; Jaeger, Martin; Maier, Dirk; Südkamp, Norbert P; Ogon, Peter

    2014-11-20

    The purpose of the present study was to investigate the accuracy of Ultrasound (US), conventional X-Ray (CX) and Computed Tomography (CT) to estimate the total count, localization, morphology and consistency of Calcium deposits (CDs) in the rotator cuff. US, CX and CT imaging was performed pre-operatively in 151 patients who underwent arthroscopic removal of CDs in the rotator cuff. In all procedures: (1) total CD counts were determined, (2) the CDs appearance in each image modality was correlated to the intraoperative consistency and (3) CDs were localized in their relation to the acromion using US, CX and CT. Using US158 CDs, using CT 188 CDs and using CX 164 CDs were identified. Reliable localization of the CDs was possible with all used diagnostic modalities. CT revealed 49% of the CDs to be septated, out of which 85% were uni- and 15% multiseptated. CX was not suitable for prediction of CDs consistency. US reliably predicted viscous-solid CDs consistency only when presenting with full sound extinction (PPV 84.6%) . CT had high positive and negative predictive values for detection of liquid-soft (PPV 92.9%) and viscous-solid (PPV 87.8%) CDs. US and CX are sufficient for preoperative planning of CD removal with regards to localization and prediction of consistency if the deposits present with full sound extinction. This is the case in the majority of the patients. However, in patients with missing sound extinction CT can be recommended if CDs consistency of the deposits should be determined. Satellite deposits or septations are regularly present, which is of importance if complete CD removal is aspired.

  15. Development of an MRI/x-ray/ultrasound compatible marker for pre-operative breast tumour localization

    International Nuclear Information System (INIS)

    Li Yangmei; Wang, Jianxiong; Holloway, Claire; Plewes, Donald B

    2005-01-01

    This paper describes an in vitro investigation into the composition, structure and development of an magnetic resonance imaging (MRI), ultrasound (US) and x-ray imaging compatible marker for breast tumour localization. The marker is composed of 0.4-0.6 mm glass and iron-containing aluminium microspheres suspended in a gelatin matrix. The final form of the marker is a cylindrical shape 7 mm long with 2.05 mm diameter to facilitate delivery through a 12 gauge biopsy needle. To get optimal reflectivity for the US contrast, the glass microsphere concentration was found to be 40% by weight. US contrast is independent of marker orientation and the cylindrical shape made its US signal appearance distinctive thus ensuring confident identification. To control the MRI contrast, iron content was varied to generate a clear and local susceptibility signal void to reflect the marker position. Optimal iron content was found to be 52 μg iron which produced a clear signal void in spoiled gradient recalled MR images. The appearance of the susceptibility artefact is determined by the marker's shape, orientation and echo time. The final marker produces a dark artefact in MRI while appears as a clear hyperintense structure with acoustic shadowing in US images. The x-ray image showed the marker as a radio-opaque structure. This in vitro study demonstrates that the marker forms an alternative to traditional wire localization currently used for breast surgical procedures and creates new opportunities for US guided surgical procedures

  16. Ultrasound contrast-agent improves imaging of lower limb occlusive disease

    DEFF Research Database (Denmark)

    Eiberg, J P; Hansen, M A; Jensen, F

    2003-01-01

    to evaluate if ultrasound contrast-agent infusion could improve duplex-ultrasound imaging of peripheral arterial disease (PAD) and increase the agreement with digital subtraction arteriography (DSA).......to evaluate if ultrasound contrast-agent infusion could improve duplex-ultrasound imaging of peripheral arterial disease (PAD) and increase the agreement with digital subtraction arteriography (DSA)....

  17. Advantages of preoperative ultrasound in conjunction with lymphoscintigraphy in detecting malignant melanoma metastases in sentinel lymph nodes: a retrospective analysis in 221 patients with malignant melanoma AJCC Stages I and II.

    Science.gov (United States)

    Stoffels, I; Dissemond, J; Poeppel, T; Klötgen, K; Hillen, U; Körber, A; Schadendorf, D; Klode, J

    2012-01-01

    Sentinel lymph node excision (SLNE) for the detection of regional nodal metastases and staging of malignant melanoma has resulted in some controversies in international discussions as it is a surgical intervention with potential morbidity. The present retrospective study seeks to clarify the reliability of preoperative ultrasonography (US) in direct comparison to the result of SLNE and seeks to identify potential advantages of preoperative ultrasound if performed in conjunction with lymphoscintigraphy in detecting malignant melanoma metastases in sentinel lymph node (SLN). We retrospectively analysed data from 221 patients with primary malignant melanoma with a Breslow index of ≥ 1.0 mm. Of the 221 patients, 77.4% (n = 171) had a negative SLN. In 50 patients (22.6%), the histopathological investigation of 71 excised lymph nodes resulted in a positive SLN. The US examination demonstrated a sensitivity of 13.6%, a specificity of 96.9%, a positive predictive value of 97.2% and a negative predictive value of 12.6%. SLNE alone shows a sensitivity of 94%, a specificity of 98.6%, a positive predictive value of 100% and a negative predictive value of 98.3%. Preoperative US in conjunction with dynamic lymphoscintigraphy, followed by SLNE, demonstrated a detecting ratio of 100% (n = 28) for micrometastases and 98.6% (n = 42/43) for macrometastases. In conclusion, this study confirms that preoperative US alone cannot replace the vital information obtained during dynamic lymphoscintigraphy. But preoperative US is an important component of the staging procedure in melanoma patients and has clear advantages when performed in conjunction with dynamic lymphoscintigraphy. Therefore, we recommend preoperative US before every SLNE. © 2011 The Authors. Journal of the European Academy of Dermatology and Venereology © 2011 European Academy of Dermatology and Venereology.

  18. Accurate perioperative flow measurement of the portal vein and hepatic and renal artery: A role for preoperative MRI?

    Energy Technology Data Exchange (ETDEWEB)

    Vermeulen, Mechteld A.R., E-mail: mar.vermeulen@vumc.nl [Department of Surgery, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Ligthart-Melis, Gerdien C., E-mail: g.ligthart-melis@vumc.nl [Department of Internal Medicine, Dietetics and Nutritional Sciences, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Buijsman, René, E-mail: renebuysman@gmail.com [Department of Surgery, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Siroen, Michiel P.C., E-mail: m.siroen6@upcmail.nl [Department of Surgery, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Poll, Marcel C.G. van de, E-mail: mcg.vandepoll@ah.unimaas.nl [Department of Surgery, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ Maastricht (Netherlands); Boelens, Petra G., E-mail: p.boelens@mumc.nl [Department of Surgery, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ Maastricht (Netherlands); Dejong, Cornelis H.C., E-mail: chc.dejong@mumc.nl [Department of Surgery, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ Maastricht (Netherlands); Schaik, Cors van, E-mail: c.vanschaik@vumc.nl [Department of Radiology, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Hofman, Mark B.M., E-mail: mbm.hofman@vumc.nl [Department of Physics and Medical Technology, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Leeuwen, Paul A.M. van, E-mail: pam.vleeuwen@vumc.nl [Department of Surgery, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands)

    2012-09-15

    Background: Quantification of abdominal blood flow is essential for a variety of gastrointestinal and hepatic topics such as liver transplantation or metabolic flux measurement, but those need to be performed during surgery. It is not clear whether Duplex Doppler Ultrasound during surgery or MRI before surgery is the tool to choose. Objective: To examine whether preoperative evaluation of abdominal blood flow using MRI could prove to be a useful and reliable alternative for the perioperative sonographic approach. Methods: In this study portal and renal venous flow and hepatic arterial flow were sequentially quantified by preoperative MRI, preoperative and perioperative Duplex Doppler Ultrasound (DDUS). 55 Patients scheduled for major abdominal surgery were studied and methods and settings were compared. Additionally, average patient population values were compared. Results: Mean (±SD) plasmaflow measured by perioperative DDUS, preoperative DDUS and MRI, respectively was 433 ± 200/423 ± 162/507 ± 96 ml/min (portal vein); 96 ± 70/74 ± 41/108 ± 91 ml/min (hepatic artery); 248 ± 139/201 ± 118/219 ± 69 ml/min (renal vein). No differences between the different settings of DDUS measurement were detected. Equality of mean was observed for all measurements. Bland Altman Plots showed widespread margins. Hepatic arterial flow measurements correlated with each other, but portal and renal venous flow correlations were absent. Conclusions: Surgery and method (DDUS vs. MRI) do not affect mean flow values. Individual comparison is restricted due to wide range in measurements. Since MRI proves to be more reliable with respect to inter-observer variability, we recommend using mean MRI results in experimental setups.

  19. Reducing duplex examinations in patients with iatrogenic pseudoaneurysms.

    Science.gov (United States)

    Stone, Patrick A; Aburahma, Ali F; Flaherty, Sarah K

    2006-06-01

    Ultrasound-guided thrombin injection has become the initial treatment of choice for femoral access-related pseudoaneurysms. Patients typically undergo serial duplex examinations to assess for spontaneous resolution of small iatrogenic pseudoaneurysms (IPSAs) (IPSAs (>2.5 cm). We evaluated the impact of a revised treatment algorithm that includes primary treatment of both small (2.5 cm), rather than observation of smaller ones, and attempts to establish a single duplex examination via a point-of-care treatment strategy. We reviewed 105 consecutive patients treated with ultrasound-guided thrombin injection from July 2001 through September 2004. Patient, IPSAs, characteristics, and treatment methods were examined. The number of duplex examinations per patient was evaluated over the treatment interval. Also, published cost data were used to compare primary treatment of small ISPAs vs observation with serial duplex examinations. Successful thrombosis occurred in 103 (98.1%) of 105 treated pseudoaneurysms. No minor or major complications occurred after thrombin injection in either small or large ISPAs, and both failures requiring operation were in the large aneurysm group. The recurrence rate for the series was 1.9% (2/105), and both recurrences were successfully treated with an additional thrombin injection. A single injection was successful in treating 43 (97.7%) of 44 small (IPSAs, and one required a second injection. Patients had an average of 3.3 duplex examinations in our first year of treatment experience, which declined to 1.5 by our third year with the institution of a point-of-care service model for all pseudoaneurysms. Based on this decreased use of duplex examination and an average treatment cohort of 35 IPSA patients per year our institution, we determined this results in a reduction of 35 hours of laboratory time and nearly 70 ultrasounds per year. Similarly for small pseudoaneurysms, a point-of-service primary treatment program rather than observation

  20. Preoperative mapping of the saphenous vein

    DEFF Research Database (Denmark)

    Levi-Mazloum, Niels Donald; Sillesen, H; Nielsen, Tina G

    1996-01-01

    A series of 124 patients had their greater saphenous vein assessed with duplex ultrasound scanning prior to planned infrainguinal bypass procedures. 33 (27%) bypass procedures thrombosed within the first year. A naturally occurring optimal vein diameter was discovered: 5.0-6.5 mm at mid-thigh lev...

  1. Preoperative mapping of the saphenous vein

    DEFF Research Database (Denmark)

    Levi-Mazloum, Niels Donald; Sillesen, H; Nielsen, Tina G

    1995-01-01

    A consecutive series of 92 patients had their greater saphenous vein assessed with duplex ultrasound scanning prior to planned infrainguinal bypass procedures. A naturally occurring optimal vein diameter was discovered. It was significantly correlated with higher postoperative ankle-brachial pres......-brachial pressure index (ABI) and lesser early postoperative thrombosis. A significant linear regression was found between the pre and postoperative vein diameter....

  2. Vesicoureteral Reflux and Duplex Systems

    OpenAIRE

    Thomas, John C.

    2008-01-01

    Vesicoureteral reflux (VUR) is the most common anomaly associated with duplex systems. In addition to an uncomplicated duplex system, reflux can also be secondary in the presence of an ectopic ureterocele with duplex systems. Controversy exists in regard to the initial and most definitive management of these anomalies when they coexist. This paper will highlight what is currently known about duplex systems and VUR, and will attempt to provide evidence supporting the various surgical approa...

  3. Vascular ultrasound.

    Science.gov (United States)

    Pilcher, D B; Ricci, M A

    1998-04-01

    Surgeon-interpreted diagnostic ultrasound has become the preferred screening test and often the definitive test for the diagnosis of arterial stenosis, aneurysm, and venous thrombosis. As a modality for surveillance, its noninvasive quality makes it particularly appealing as the test of choice to screen patients for abdominal aortic aneurysms or to perform follow-up examinations on those patients with a carotid endartectomy or in situ bypass grafts. The increasing reliance on intraoperative duplex imaging of vascular procedures demands that the surgeon learn the skills to perform the studies without a technologist or radiologist to interpret the examination.

  4. Ultrasound pregnancy

    Science.gov (United States)

    Pregnancy sonogram; Obstetric ultrasonography; Obstetric sonogram; Ultrasound - pregnancy; IUGR - ultrasound; Intrauterine growth - ultrasound; Polyhydramnios - ultrasound; Oligohydramnios - ultrasound; ...

  5. The Duplex Society.

    Science.gov (United States)

    Schorr, Alvin L.

    1984-01-01

    The duplex society, in which the poor live in close proximity to others but in a separate compartment, is already with us. Unless something deeply changes about family income, more than one-third of future generations will come to adulthood having spent a portion of their childhood in official poverty. (RM)

  6. Duplex tab exhaust nozzle

    Science.gov (United States)

    Gutmark, Ephraim Jeff (Inventor); Martens, Steven (nmn) (Inventor)

    2012-01-01

    An exhaust nozzle includes a conical duct terminating in an annular outlet. A row of vortex generating duplex tabs are mounted in the outlet. The tabs have compound radial and circumferential aft inclination inside the outlet for generating streamwise vortices for attenuating exhaust noise while reducing performance loss.

  7. Considerations in Duplex Investment.

    Science.gov (United States)

    Wright, Arthur; Goen, Tom

    Problems of duplex investment are noted in the introduction to this booklet designed to provide a technique by which the investment decision can be approached, develop estimates of typical costs and returns under differing conditions, and encourage investors to analyze objectives and conditions before the decision to buy or build is made. A…

  8. Impact of preoperative screening for rectal colonization with fluoroquinolone-resistant enteric bacteria on the incidence of sepsis following transrectal ultrasound guided prostate biopsy

    Directory of Open Access Journals (Sweden)

    Farrell JJ

    2017-02-01

    Full Text Available John J Farrell,1,2 Jennifer L Hicks,3 Stephanie E Wallace,2 Allen D Seftel4,5 1Department of Medicine, Division of Infectious Diseases, University of Illinois College of Medicine, 2Department of Laboratory Medicine, Division of Clinical Microbiology & Serology, OSF/Saint Francis Medical Center, 3Department of Urology, OSF /Saint Francis Medical Center, Peoria, IL, 4Department of Urology, Cooper University Hospital, 5Department of Surgery, Cooper University School of Medicine, Camden, NJ, USA Abstract: With the universal adoption of antibiotic prophylaxis prior to prostate biopsy, the current risk of post-biopsy infection (including sepsis is <2%. Preoperative prophylactic antibiotic regimens can vary, and although fluoroquinolones have emerged as the standard of care, there is no universally agreed upon preoperative antibiotic regimen. Recently, an increase in the proportion of postoperative infections caused by fluoroquinolone-resistant Escherichia coli (as well as other Enterobacteriaceae has led to the exploration of simple, practical, and cost-effective methods to minimize this postoperative infection risk. We performed a prospective, nonrandomized, controlled study of preoperative rectal cultures to screen for rectal colonization with fluoroquinolone-resistant bacteria using ciprofloxacin-supplemented MacConkey agar culture media. To evaluate the feasibility and practicality of this test, one provider used the results of rectal swab cultures collected during the preoperative outpatient evaluation to adjust each patient’s preoperative antibiotic prophylaxis when fluoroquinolone-resistant enteric bacteria were detected, whereas two other providers continued usual preoperative care and empiric antimicrobial prophylaxis. Rectal colonization with fluoroquinolone-resistant bacteria was detected in 19/152 (12.5% of patients. In our intention-to-treat analysis (N=268, the rate of post-biopsy sepsis was 3.6% lower in the group that was screened

  9. Podiatry Ankle Duplex Scan: Readily Learned and Accurate in Diabetes.

    Science.gov (United States)

    Normahani, Pasha; Powezka, Katarzyna; Aslam, Mohammed; Standfield, Nigel J; Jaffer, Usman

    2018-03-01

    We aimed to train podiatrists to perform a focused duplex ultrasound scan (DUS) of the tibial vessels at the ankle in diabetic patients; podiatry ankle (PodAnk) duplex scan. Thirteen podiatrists underwent an intensive 3-hour long simulation training session. Participants were then assessed performing bilateral PodAnk duplex scans of 3 diabetic patients with peripheral arterial disease. Participants were assessed using the duplex ultrasound objective structured assessment of technical skills (DUOSATS) tool and an "Imaging Score". A total of 156 vessel assessments were performed. All patients had abnormal waveforms with a loss of triphasic flow. Loss of triphasic flow was accurately detected in 145 (92.9%) vessels; the correct waveform was identified in 139 (89.1%) cases. Participants achieved excellent DUOSATS scores (median 24 [interquartile range: 23-25], max attainable score of 26) as well as "Imaging Scores" (8 [8-8], max attainable score of 8) indicating proficiency in technical skills. The mean time taken for each bilateral ankle assessment was 20.4 minutes (standard deviation ±6.7). We have demonstrated that a focused DUS for the purpose of vascular assessment of the diabetic foot is readily learned using intensive simulation training.

  10. Implementation of real-time duplex synthetic aperture ultrasonography

    DEFF Research Database (Denmark)

    Hemmsen, Martin Christian; Larsen, Lee; Kjeldsen, Thomas

    2015-01-01

    This paper presents a real-time duplex synthetic aperture imaging system, implemented on a commercially available tablet. This includes real-time wireless reception of ultrasound signals and GPU processing for B-mode and Color Flow Imaging (CFM). The objective of the work is to investigate the im...... and that the required bandwidth between the probe and processing unit is within the current Wi-Fi standards....

  11. Preoperative evaluation

    International Nuclear Information System (INIS)

    Murphy, C.H.; Murphy, M.R.

    1987-01-01

    The value of a preoperative chest radiograph is twofold. The examination may reveal unsuspected pathology that would alter the approach to surgery of anesthesia. Secondly, it provides a baseline or reference from which to evaluate subsequent post-operative films. The percentage of detection of unsuspected pathology on preoperative chest radiographs has been shown to be exceedingly small in certain patient populations. The authors do not recommend routine use of preoperative chest radiographs in children or in adults under the age of 40 who do not smoke, unless (1) the surgical disease has chest manifestations; (2) there is historic or clinical evidence of a coexisting disease with chest involvement; or (3) there is a likelihood that post-operative management will require follow-up films

  12. The clinical importance and prediction of steal following femoro-femoral cross-over bypass: study of the donor iliac artery by intravascular ultrasound, arteriography, duplex scanning and pressure measurements

    DEFF Research Database (Denmark)

    Vogt, K C; Rasmussen, J G; Schroeder, T V

    2000-01-01

    to evaluate the clinical significance of the steal phenomenon following femoro-femoral bypass, and whether the addition of intravascular ultrasound (IVUS) to the established examinations of the donor iliac artery can improve the prediction of patients who will develop steal.......to evaluate the clinical significance of the steal phenomenon following femoro-femoral bypass, and whether the addition of intravascular ultrasound (IVUS) to the established examinations of the donor iliac artery can improve the prediction of patients who will develop steal....

  13. Pre-Operative Planning Using Real-Time Virtual Sonography, an MRI/Ultrasound Image Fusion Technique, for Breast-Conserving Surgery in Patients with Non-Mass Enhancement on Breast MRI: A Preliminary Study.

    Science.gov (United States)

    Ando, Takahito; Ito, Yukie; Ido, Mirai; Osawa, Manami; Kousaka, Junko; Mouri, Yukako; Fujii, Kimihito; Nakano, Shogo; Kimura, Junko; Ishiguchi, Tsuneo; Watanebe, Rie; Imai, Tsuneo; Fukutomi, Takashi

    2018-07-01

    The purpose of this retrospective study was to evaluate the effect of pre-operative planning using real-time virtual sonography (RVS), a magnetic resonance imaging (MRI)/ultrasound (US) image fusion technique on breast-conserving surgery (BCS) in patients with non-mass enhancement (NME) on breast MRI. Between 2011 and 2015, we enrolled 12 consecutive patients who had lesions with NME that exceeded the US hypo-echoic area, in which it was particularly difficult to evaluate the tumor margin. During pre-operative planning before breast-conserving surgery, RVS was used to delineate the enhancing area on the breast surface after additional supine breast MRI was performed. We analyzed both the surgical margin positivity rate and the re-operation rate. All NME lesions corresponded to the index cancer. In all patients, the diameter of the NME lesion was greater than that of the hypo-echoic lesion. The median diameters of the NME and hypo-echoic lesions were 24 mm (range: 12-39 mm) and 8.0 mm (range: 4.9-18 mm), respectively (p = 0.0002). After RVS-derived skin marking was performed on the surface of the affected breast, lumpectomy and quadrantectomy were conducted in 7 and 5 patients, respectively. The surgical margins were negative in 10 (83%) patients. Two patients with positive margins were found to have ductal carcinoma in situ in 1 duct each, 2.4 and 3.2 mm from the resection margin, respectively. None of the patients required additional resection. Although further prospective studies are required, the findings of our preliminary study suggest that it is very well possible that the use of RVS-derived skin marking during pre-operative planning for BCS in patients with NME would have resulted in surgical outcomes similar to or better than those obtained without the use of such marking. Copyright © 2018. Published by Elsevier Inc.

  14. Transvaginal ultrasound versus magnetic resonance imaging for preoperative assessment of myometrial infiltration in patients with endometrial cancer: a systematic review and meta-analysis

    Science.gov (United States)

    2017-01-01

    Objective To compare the diagnostic accuracy of transvaginal ultrasound (TVS) and magnetic resonance imaging (MRI) for detecting myometrial infiltration (MI) in endometrial carcinoma. Methods An extensive search of papers comparing TVS and MRI in assessing MI in endometrial cancer was performed in MEDLINE (PubMed), Web of Science, and Cochrane Database from January 1989 to January 2017. Quality was assessed using Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. Results Our extended search identified 747 citations but after exclusions we finally included in the meta-analysis 8 articles. The risk of bias for most studies was low for most 4 domains assessed in QUADAS-2. Overall, pooled estimated sensitivity and specificity for diagnosing deep MI were 75% (95% confidence interval [CI]=67%–82%) and 82% (95% CI=75%–93%) for TVS, and 83% (95% CI=76%–89%) and 82% (95% CI=72%–89%) for MRI, respectively. No statistical differences were found when comparing both methods (p=0.314). Heterogeneity was low for sensitivity and high for specificity for TVS and MRI. Conclusion MRI showed a better sensitivity than TVS for detecting deep MI in women with endometrial cancer. However, the difference observed was not statistically significant. PMID:29027404

  15. Duplex evaluation following femoropopliteal angioplasty and stenting: criteria and utility of surveillance.

    Science.gov (United States)

    Baril, Donald T; Marone, Luke K

    2012-07-01

    Surveillance following lower extremity bypass, carotid endarterectomy, and endovascular aortic aneurysm repair has become the standard of care at most institutions. Conversely, surveillance following lower extremity endovascular interventions is performed somewhat sporadically in part because the duplex criteria for recurrent stenoses have been ill defined. It appears that duplex surveillance after peripheral endovascular interventions, as with conventional bypass, is beneficial in identifying recurrent lesions which may preclude failure and occlusion. In-stent stenosis following superficial femoral artery angioplasty and stenting can be predicted by both peak systolic velocity and velocity ratio data as measured by duplex ultrasound. Duplex criteria have been defined to determine both ≥50% in-stent stenosis and ≥80% in-stent stenosis. Although not yet well studied, it appears that applying these criteria during routine surveillance may assist in preventing failure of endovascular interventions.

  16. Maximizing synchronizability of duplex networks

    Science.gov (United States)

    Wei, Xiang; Emenheiser, Jeffrey; Wu, Xiaoqun; Lu, Jun-an; D'Souza, Raissa M.

    2018-01-01

    We study the synchronizability of duplex networks formed by two randomly generated network layers with different patterns of interlayer node connections. According to the master stability function, we use the smallest nonzero eigenvalue and the eigenratio between the largest and the second smallest eigenvalues of supra-Laplacian matrices to characterize synchronizability on various duplexes. We find that the interlayer linking weight and linking fraction have a profound impact on synchronizability of duplex networks. The increasingly large inter-layer coupling weight is found to cause either decreasing or constant synchronizability for different classes of network dynamics. In addition, negative node degree correlation across interlayer links outperforms positive degree correlation when most interlayer links are present. The reverse is true when a few interlayer links are present. The numerical results and understanding based on these representative duplex networks are illustrative and instructive for building insights into maximizing synchronizability of more realistic multiplex networks.

  17. Ultrasound -- Pelvis

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    Full Text Available ... Ultrasound - Abdomen Obstetric Ultrasound Ultrasound - Prostate Kidney and Bladder Stones Abnormal Vaginal Bleeding Ovarian Cancer Images related to Ultrasound - Pelvis Sponsored by Please ...

  18. Ultrasound -- Pelvis

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    Full Text Available ... Children's (Pediatric) Ultrasound - Abdomen Obstetric Ultrasound Ultrasound - Prostate Kidney and Bladder Stones Abnormal Vaginal Bleeding Ovarian Cancer Images related to Ultrasound - Pelvis Sponsored by Please ...

  19. Ultrasound -- Pelvis

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    Full Text Available ... specific content. Related Articles and Media Sonohysterography Ultrasound - Abdomen Children's (Pediatric) Ultrasound - Abdomen Obstetric Ultrasound Ultrasound - Prostate Kidney and ...

  20. Welding of duplex and super-duplex stainless steels

    International Nuclear Information System (INIS)

    Van Nassau, L.; Meelker, H.; Hilkes, J.

    1994-01-01

    After a recall of the commercial designation of duplex or super-duplex steels (22-27% Cr, 4-8% Ni, 0.1-0.3% N with or without Mo (1.5-4%)) and of some metallurgical properties (phase diagrams, microstructure, ferrite determination, heat treatment and aging), welding technologies are synthetically presented (advantages-disadvantages of each process, metals filler, parameters of the welding processes, heat treatments after welding, cleaning, passivation, properties (mechanical, corrosion resistance) of the welded pieces). (A.B.). 28 refs. 5 figs., 15 tabs., 1 annexe

  1. There is no benefit to universal carotid artery duplex screening before a major cardiac surgical procedure.

    Science.gov (United States)

    Adams, Brian C; Clark, Ross M; Paap, Christina; Goff, James M

    2014-01-01

    Perioperative stroke is a devastating complication after cardiac surgery. In an attempt to minimize this complication, many cardiac surgeons routinely preoperatively order carotid artery duplex scans to assess for significant carotid stenosis. We hypothesize that the routine screening of preoperative cardiac surgery patients with carotid artery duplex scans detects few patients who would benefit from carotid intervention or that a significant carotid stenosis reliably predicts stroke risk after cardiac surgery. A retrospective review identified 1,499 patients who underwent cardiac surgical procedures between July 1999 and September 2010. Data collected included patient demographics, comorbidities, history of previous stroke, preoperative carotid artery duplex scan results, location of postoperative stroke, and details of carotid endarterectomy (CEA) procedures before, in conjunction with, or after cardiac surgery. Statistical methods included univariate analysis and Fisher's exact test. Twenty-six perioperative strokes were identified (1.7%). In the 21 postoperative stroke patients for whom there is complete carotid artery duplex scan data, 3 patients had a hemodynamically significant lesion (>70%) and 1 patient underwent unilateral carotid CEA for bilateral disease. Postoperative strokes occurred in the anterior cerebral circulation (69.2%), posterior cerebral circulation (15.4%), or both (15.4%). Patient comorbidities, preoperative carotid artery duplex scan screening velocities, or types of cardiac surgical procedure were not predictive for stroke. Thirteen patients (0.86%) underwent CEA before, in conjunction with, or after cardiac surgery. Two of these patients had symptomatic disease, 1 of whom underwent CEA before and the other after his cardiac surgery. Of the 11 asymptomatic patients, 2 underwent CEA before, 3 concurrently, and 6 after cardiac surgery. Left main disease (≥50% stenosis), previous stroke, and peripheral vascular disease were found to be

  2. Quality assurance of lower limb venous duplex scans performed by vascular surgeons.

    Science.gov (United States)

    Kordowicz, A; Ferguson, G; Salaman, R; Onwudike, M

    2015-02-01

    Duplex scanning is the gold standard for investigating venous reflux; increasingly surgeons perform these scans themselves. There has been no data published analysing the accuracy of Duplex scans performed by vascular surgeons. We aimed to evaluate an objective method of comparing the results of lower limb Duplex scans performed by one consultant vascular surgeon with those performed by a vascular technologist. We assessed 100 legs with symptomatic varicose veins. Each patient underwent two lower limb venous Duplex scans; one performed by a consultant vascular surgeon and one by a vascular technologist. Scan results were randomised and sent to two consultant vascular surgeons blinded to the identity and experience of the sonographer. They were asked to recommend treatment. A k score was calculated in each case to assess the level of agreement between the scans performed by the consultant and the technologist. Eighty-one patients were studied (53 females). The kappa score for assessor 1 was 0.60 (95%CI:0.44-0.75) and for assessor 2 was 0.62 (95%CI:0.48-0.75). k scores >0.60 represent a substantial strength of agreement. Duplex scans performed by this surgeon were comparable to those performed by a vascular technologist. It is possible to quality-assure duplex performed by vascular surgeons without directly observing the scanning process or reviewing digitally recorded images. We propose standardisation of training, assessment and quality assurance for vascular surgeons wishing to perform ultrasound scans.

  3. Impact of Duplex arterial mapping on decision making in non-acute ischemic limb patients.

    Science.gov (United States)

    Elbadawy, A; Aly, H; Ibrahim, M; Bakr, H

    2015-12-01

    The aim of this study was to demonstrate the impact of Duplex arterial mapping on decision making in non-acute ischemic limb patient group reporting pain onset between 15 days and 3 months. We prospectively evaluated patients presented with critical limb ischemia who reported pain onset of duration between 15 days and 3 months in one-year period. Our series included thirty cases (mean age=61.3 years old), as Duplex arterial mapping was the sole preoperative imaging tool performed in all of them. All patients, in whom duplex indicated thrombosis in long occluded segments, were candidates for fluoroscopically guided thrombectomy. When Duplex defined chronic arterial occlusions, patients underwent endovascular or bypass revascularisation procedures. Impact of Duplex wall interrogation on decision-making between the two groups (subacute and chronic) was measured. Duplex arterial mapping categorized correctly all 30 patients into either subacute ischemia with removable clot (N.=14) or chronic ischemia (N.=16). Fluoroscopic guided thrombectomy was performed in 14 cases when Duplex advised long occluded arterial segments as indicted by intact intima with echogenic thrombus inside. Bypass surgery was performed in 8 patients. Percutaneous transluminal angioplasty (PTA) was done in 7 cases and thrombendartrectomy of common femoral artery in a single case. One-year patency rate in our series was 86.6%. It was 71.4% in thrombosis group. Limb salvage rate was 93.3%. Duplex arterial mapping could be used to differentiate the subacute ischemia with removable thrombus and chronic arterial occlusions guiding for the best revascularization procedure accordingly.

  4. The preoperative evaluation prevent the postoperative complications of thyroidectomy

    Directory of Open Access Journals (Sweden)

    Chien-Feng Huang

    2015-03-01

    Conclusions: The success of thyroid surgery depends on careful preoperative planning, including a preoperative neck ultrasound to determine the proximity of the nodule to the recurrent laryngeal nerve course, and the consideration of the type of anesthesia, adjuvant devices for intra-op monitoring of the RLN, and surgical modalities. Our results suggest that preoperative evaluation implementations are positively associated with strategy of surgery and postoperative hypocalcemia prevention.

  5. Prostate Ultrasound

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    Full Text Available ... Physician Resources Professions Site Index A-Z Ultrasound - Prostate Ultrasound of the prostate uses sound waves to ... Ultrasound Imaging? What is Ultrasound Imaging of the Prostate? Ultrasound is safe and painless, and produces pictures ...

  6. Achieving single channel, full duplex wireless communication

    KAUST Repository

    Choi, Jung Il; Jain, Mayank; Srinivasan, Kannan; Levis, Phil; Katti, Sachin

    2010-01-01

    This paper discusses the design of a single channel full-duplex wireless transceiver. The design uses a combination of RF and baseband techniques to achieve full-duplexing with minimal effect on link reliability. Experiments on real nodes show the full-duplex prototype achieves median performance that is within 8% of an ideal full-duplexing system. This paper presents Antenna Cancellation, a novel technique for self-interference cancellation. In conjunction with existing RF interference cancellation and digital baseband interference cancellation, antenna cancellation achieves the amount of self-interference cancellation required for full-duplex operation. The paper also discusses potential MAC and network gains with full-duplexing. It suggests ways in which a full-duplex system can solve some important problems with existing wireless systems including hidden terminals, loss of throughput due to congestion, and large end-to-end delays. Copyright 2010 ACM.

  7. Ultrasound assessment of great saphenous vein insufficiency

    Directory of Open Access Journals (Sweden)

    Chander RK

    2015-06-01

    Full Text Available Rajiv K Chander,1 Thomas S Monahan1,2 1Section of Vascular Surgery, Department of Surgery, University of Maryland School of Medicine, 2Department of Surgery, Baltimore Veterans Affairs Medical Center, Baltimore, MD, USA Abstract: Duplex ultrasonography is the ideal modality to assess great saphenous vein insufficiency. Duplex ultrasonography incorporates both gray scale images to delineate anatomy and color-Doppler imaging that visualizes the flow of blood in a structure. Assessment of great saphenous vein requires definition of the anatomy, augmentation of flow, evaluation for both superficial and deep vein thrombosis, and determining the presence of reflux. Currently, evolution in the treatment of reflux also relies on ultrasound for the treatment of the disease. Understanding the utilization of the ultrasound for the diagnosis and treatment of greater saphenous vein reflux is important for practitioners treating reflux disease. Keywords: duplex ultrasonography, small saphenous vein 

  8. Probabilistic Medium Access Control for Full-Duplex Networks with Half-Duplex Clients

    OpenAIRE

    Chen, Shih-Ying; Huang, Ting-Feng; Lin, Kate Ching-Ju; Hong, H. -W. Peter; Sabharwal, Ashutosh

    2016-01-01

    The feasibility of practical in-band full-duplex radios has recently been demonstrated experimentally. One way to leverage full-duplex in a network setting is to enable three-node full-duplex, where a full- duplex access point (AP) transmits data to one node yet simultaneously receives data from another node. Such three-node full-duplex communication however introduces inter-client interference, directly impacting the full-duplex gain. It hence may not always be beneficial to enable three-nod...

  9. Role of magnetic resonance urography in diagnosis of duplex renal system: Our initial experience at a tertiary care institute

    Directory of Open Access Journals (Sweden)

    Milind P Joshi

    2009-01-01

    Full Text Available Aim: To determine diagnostic value of magnetic resonance urography in cases of duplex renal system. Method: Twenty cases between five month to nine years with suspected or known duplex renal system were evaluated by ultrasound (USG, micturating cystourethrography (MCU, intravenous urography (IVU and magnetic resonance urography (MRU. The findings of these diagnostic imaging studies were then compared with each other and against the results of final diagnosis established at surgery. Results: Duplex renal system could be identified in two of these cases on USG, was diagnosed in four in IVU and could be diagnosed in all cases with MRU. Conclusion: MRU is superior and far accurate than IVU, MCU and USG in diagnosing duplex renal system.

  10. Prostate Ultrasound

    Medline Plus

    Full Text Available ... through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. Prostate ultrasound, also called transrectal ultrasound, provides ...

  11. The effect of a simulation training package on skill acquisition for duplex arterial stenosis detection.

    Science.gov (United States)

    Jaffer, Usman; Normahani, Pasha; Singh, Prashant; Aslam, Mohammed; Standfield, Nigel J

    2015-01-01

    In vascular surgery, duplex ultrasonography is a valuable diagnostic tool in patients with peripheral vascular disease, and there is increasing demand for vascular surgeons to be able to perform duplex scanning. This study evaluates the role of a novel simulation training package on vascular ultrasound (US) skill acquisition. A total of 19 novices measured predefined stenosis in a simulated pulsatile vessel using both peak systolic velocity ratio (PSVR) and diameter reduction (DR) methods before and after a short period of training using a simulated training package. The training package consisted of a simulated pulsatile vessel phantom, a set of instructional videos, duplex ultrasound objective structured assessment of technical skills (DUOSATS) tool, and a portable US scanner. Quantitative metrics (procedure time, percentage error using PSVR and DR methods, DUOSAT scores, and global rating scores) before and after training were compared. Subjects spent a median time of 144 mins (IQR: 60-195) training using the simulation package. Subjects exhibited statistically significant improvements when comparing pretraining and posttraining DUOSAT scores (pretraining = 17 [16-19.3] vs posttraining = 30 [27.8-31.8]; p duplex images in a pulsatile simulated phantom following a short period of goal direct training using a simulation training package. A simulation training package may be a valuable tool for integration into a vascular training program. However, further work is needed to explore whether these newly attained skills are translated into clinical assessment. Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.

  12. Prostate Ultrasound

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    Full Text Available ... ultrasound or with a rectal examination, an ultrasound-guided biopsy can be performed. This procedure involves advancing ... of the Prostate) Prostate Cancer Ultrasound- and MRI-Guided Prostate Biopsy Images related to Ultrasound - Prostate Sponsored ...

  13. Ultrasound -- Pelvis

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    Full Text Available ... Ultrasound - Pelvis Ultrasound imaging of the pelvis uses sound waves to produce pictures of the structures and ... pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound scanning or ...

  14. Prostate Ultrasound

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    Full Text Available ... Z Ultrasound - Prostate Ultrasound of the prostate uses sound waves to produce pictures of a man’s prostate ... pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound scanning or ...

  15. Ultrasound -- Pelvis

    Science.gov (United States)

    ... endometrial polyps fibroids cancer, especially in patients with abnormal uterine bleeding Some physicians also use 3-D ultrasound or ... Obstetric Ultrasound Ultrasound - Prostate Kidney and Bladder Stones Abnormal Vaginal Bleeding Ovarian Cancer Images related to Ultrasound - Pelvis Sponsored ...

  16. Overall performance of the duplex Stirling refrigerator

    International Nuclear Information System (INIS)

    Erbay, L. Berrin; Ozturk, M. Mete; Doğan, Bahadır

    2017-01-01

    Highlights: • Overall performance coefficient of duplex Stirling refrigerator was investigated. • A definite region for the coefficient of performance of the refrigerator in duplex Stirling is identified. • A definite region for the thermal efficiency of the heat engine in duplex Stirling is identified. • Benchmark values and design bounds of the duplex Stirling refrigerator were obtained. - Abstract: The duplex Stirling refrigerator is an integrated refrigerator consists of Stirling cycle engine and Stirling cycle refrigerator used for cooling. The equality of the work generation of the heat engine to the work consumption of the refrigerator is the primary constraint of the duplex Stirling. The duplex Stirling refrigerator is investigated thermodynamically by considering the effects of constructional and operational parameters which are namely the temperature ratios for heat engine and refrigerator, and the compression ratios for both sides. The primary concern is given to the parametric effects on the overall coefficient of performance of the duplex Stirling refrigerator. The given diagrams provide a design bounds and benchmark results that allows seeing the big picture about the cooling load and heat input relation. Moreover they ease to determine the corresponding work rate to the target cooling load. As regard to the obtained results, a definite region for coefficient of performance of the refrigerator and a definite region for the thermal efficiency of the heat engine of the duplex Stirling are identified.

  17. ULTRASOUND AND COMPUTED TOMOGRAPHIC DIAGNOSIS OF OPTIC NERVE TUMORS

    Directory of Open Access Journals (Sweden)

    S. V. Saakyan

    2012-01-01

    Full Text Available A comprehensive examination was made in 93 patients, including 18 children, with tumors of the optic nerve (ON. Duplex ultrasound scanning was performed in 39 patients, of them there were 11 patients with ON gliomas and 28 with ON meningiomas. The specific computed tomographic and echographic signs of ON glioma and meningiomas were detected. The studies have shown that duplex ultrasound scanning and structural computed tomography of orbital sockets are highly informative complementary imaging procedures for ON tumors, which permits one to make their correct diagnosis, to specify surgical volume, and to plan adequate treatment.

  18. Prehospital Ultrasound

    Directory of Open Access Journals (Sweden)

    Jen-Tang Sun

    2014-06-01

    Full Text Available Ultrasound is a commonly used diagnostic tool in clinical conditions. With recent developments in technology, use of portable ultrasound devices has become feasible in prehospital settings. Many studies also proved the feasibility and accuracy of prehospital ultrasound. In this article, we focus on the use of prehospital ultrasound, with emphasis on trauma and chest ultrasound.

  19. Prolonged CT urography in duplex kidney.

    Science.gov (United States)

    Gong, Honghan; Gao, Lei; Dai, Xi-Jian; Zhou, Fuqing; Zhang, Ning; Zeng, Xianjun; Jiang, Jian; He, Laichang

    2016-05-13

    Duplex kidney is a common anomaly that is frequently associated with multiple complications. Typical computed tomography urography (CTU) includes four phases (unenhanced, arterial, parenchymal and excretory) and has been suggested to considerably aid in the duplex kidney diagnosi. Unfortunately, regarding duplex kidney with prolonged dilatation, the affected parenchyma and tortuous ureters demonstrate a lack of or delayed excretory opacification. We used prolonged-delay CTU, which consists of another prolonged-delay phase (1- to 72-h delay; mean delay: 24 h) to opacify the duplicated ureters and affected parenchyma. Seventeen patients (9 males and 8 females; age range: 2.5-56 y; mean age: 40.4 y) with duplex kidney were included in this study. Unenhanced scans did not find typical characteristics of duplex kidney, except for irregular perirenal morphology. Duplex kidney could not be confirmed on typical four-phase CTU, whereas it could be easily diagnosed in axial and CT-3D reconstruction using prolonged CTU (prolonged-delay phase). Between January 2005 and October 2010, in this review board-approved study (with waived informed consent), 17 patients (9 males and 8 females; age range: 2.5 ~ 56 y; mean age: 40.4 y) with suspicious duplex kidney underwent prolonged CTU to opacify the duplicated ureters and confirm the diagnosis. Our results suggest the validity of prolonged CTU to aid in the evaluation of the function of the affected parenchyma and in the demonstration of urinary tract malformations.

  20. Duplex ultrasound: Indications and findings in a newly created ...

    African Journals Online (AJOL)

    2015-09-21

    Sep 21, 2015 ... save more lives and limbs in the developing world. Key words: Calabar ... managed with only clinical assessment of their blood vessels and X‑rays. With the .... are supposed to be bread winners and, therefore, more fearful.

  1. Ultrasound -- Pelvis

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    Full Text Available ... a pelvic ultrasound examination. Doppler ultrasound , also called color Doppler ultrasonography, is a special ultrasound technique that ... and processes the sounds and creates graphs or color pictures that represent the flow of blood through ...

  2. Ultrasound -- Pelvis

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    Full Text Available ... Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. There are ... Ultrasound page for more information . Ultrasound examinations can help diagnose symptoms experienced by women such as: pelvic ...

  3. Ultrasound -- Pelvis

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    Full Text Available ... three types of pelvic ultrasound: abdominal, vaginal (for women), and rectal (for men). These exams are frequently ... pelvic ultrasound: abdominal ( transabdominal ) vaginal ( transvaginal / endovaginal ) for women rectal ( transrectal ) for men A Doppler ultrasound exam ...

  4. Ultrasound -- Pelvis

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    Full Text Available ... ultrasound images are captured in real-time, they can show the structure and movement of the body's ... Obstetrical Ultrasound page for more information . Ultrasound examinations can help diagnose symptoms experienced by women such as: ...

  5. Screening of Modified RNA duplexes

    DEFF Research Database (Denmark)

    Schyth, Brian Dall; Bramsen, Jesper Bertram; Kjems, Jørgen

    protection against a fish pathogenic virus. This protection corresponded with an interferon response in the fish. Here we use this fish model to screen siRNAs containing various chemical modifications of the RNA backbone for their antiviral activity, the overall aim being identification of an siRNA form......Because of sequence specific gene targeting activity siRNAs are regarded as promising active compounds in gene medicine. But one serious problem with delivering siRNAs as treatment is the now well-established non-specific activities of some RNA duplexes. Cellular reactions towards double stranded...... RNAs include the 2´-5´ oligoadenylate synthetase system, the protein kinase R, RIG-I and Toll-like receptor activated pathways all resulting in antiviral defence mechanism. We have previously shown that antiviral innate immune reactions against double stranded RNAs could be detected in vivo as partial...

  6. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. There are three types of pelvic ultrasound: ...

  7. Full Duplex Emulation via Spatial Separation of Half Duplex Nodes in a Planar Cellular Network

    DEFF Research Database (Denmark)

    Thomsen, Henning; Kim, Dong Min; Popovski, Petar

    2016-01-01

    A Full Duplex Base Station (FD-BS) can be used to serve simultaneously two Half-Duplex (HD) Mobile Stations (MSs), one working in the uplink and one in the downlink, respectively. The same functionality can be realized by having two interconnected and spatially separated Half Duplex Base Stations...... (HD-BSs), which is a scheme termed CoMPflex (CoMP for In-Band Wireless Full Duplex). A FD-BS can be seen as a special case of CoMPflex with separation distance zero. In this paper we study the performance of CoMPflex in a two-dimensional cellular scenario using stochastic geometry and compare...

  8. The Use of Color-Coded Duplex Scanning in the Selection of Patients with Lower Extremity Arterial Disease for Percutaneous Transluminal Angioplasty: A Prospective Study

    International Nuclear Information System (INIS)

    Elsman, Bernard H.P.; Legemate, Dink A.; Heyden, Frank W.H.M. van der; Vos, Henk de; Mali, Willem P.T.M.; Eikelboom, Bert C.

    1996-01-01

    Purpose: To exploit the potential benefits of percutaneous transluminal angioplasty (PTA) in patients with short obstructive lesions in the lower extremity, it is preferable to select patients suitable for PTA before proceeding to hospital admission and angiography. The aim of this prospective study was to evaluate the role of color-coded duplex scanning in the correct selection of patients for PTA and its influence on planning the approach to the lesion. Methods: On the basis of clinical history, physical examination, pressure indices, and ultrasound duplex scanning, 109 patients were scheduled for PTA. Results: The indication for PTA was correct in 103 patients (94%), while the procedure was performed successfully in 98 patients (90%). The approach to the lesion was planned successfully in the majority of patients. Conclusion: This study shows that it is justifiable to plan PTA on the basis of information obtained by duplex scanning. Results of the duplex scan may guide the catheterization route

  9. Deep vein thrombosis of lower extremity: What is the most important finding in duplex Doppler sonography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yong Soo; Koh, Byung Hee; Cho, On Koo; Rhim, Hyun Chul; Seo, Heung Suk; Hahm, Chang Kok; Kwak, Jin Young [Hanyang University College of Medicine, Seoul (Korea, Republic of)

    1993-12-15

    The positive findings of deep vein thrombosis on duplex Doppler ultrasonography such as intraluminal clot,non-compressibility of the venous lumen and abnormal or absent Doppler shift signal are well known. However, relatively hypoechoic thrombus is not always seen in sonography, and the vein is frequently compressible in partial thrombosis. In order to evaluate the most common and important findings of deep vein thrombosis, we analysed the findings at duplex Doppler ultrasound in 19 patients and compared the results with those of contrast venography in 11 patients. Duplex Doppler ultrasound examination of the common femoral and popliteal veins was performed for one extremity in 14 patients, and for both extremities in 5 (total 24 extremities). Contrast venography was performed for one extremity in 7 patients, and for both sides in 4 (total 15 extremities).Thrombosis was seen in 45.8%, non-compressibility of lumen in 75%, absent or decreased Doppler signal from common femoral vein in 95.8%. Thrombosis was seen in 41.7%, non-compressibility of lumen in 70.8%, absent or decreased Doppler shift signal from popliteal vein in 95.8%. We conclude that abnormal or absent Doppler shift signal is the most sensitive and important finding of the deep vein thrombosis

  10. Research interface on a programmable ultrasound scanner.

    Science.gov (United States)

    Shamdasani, Vijay; Bae, Unmin; Sikdar, Siddhartha; Yoo, Yang Mo; Karadayi, Kerem; Managuli, Ravi; Kim, Yongmin

    2008-07-01

    Commercial ultrasound machines in the past did not provide the ultrasound researchers access to raw ultrasound data. Lack of this ability has impeded evaluation and clinical testing of novel ultrasound algorithms and applications. Recently, we developed a flexible ultrasound back-end where all the processing for the conventional ultrasound modes, such as B, M, color flow and spectral Doppler, was performed in software. The back-end has been incorporated into a commercial ultrasound machine, the Hitachi HiVision 5500. The goal of this work is to develop an ultrasound research interface on the back-end for acquiring raw ultrasound data from the machine. The research interface has been designed as a software module on the ultrasound back-end. To increase the amount of raw ultrasound data that can be spooled in the limited memory available on the back-end, we have developed a method that can losslessly compress the ultrasound data in real time. The raw ultrasound data could be obtained in any conventional ultrasound mode, including duplex and triplex modes. Furthermore, use of the research interface does not decrease the frame rate or otherwise affect the clinical usability of the machine. The lossless compression of the ultrasound data in real time can increase the amount of data spooled by approximately 2.3 times, thus allowing more than 6s of raw ultrasound data to be acquired in all the modes. The interface has been used not only for early testing of new ideas with in vitro data from phantoms, but also for acquiring in vivo data for fine-tuning ultrasound applications and conducting clinical studies. We present several examples of how newer ultrasound applications, such as elastography, vibration imaging and 3D imaging, have benefited from this research interface. Since the research interface is entirely implemented in software, it can be deployed on existing HiVision 5500 ultrasound machines and may be easily upgraded in the future. The developed research

  11. Practical, real-time, full duplex wireless

    KAUST Repository

    Jain, Mayank; Choi, Jung Il; Kim, Taemin; Bharadia, Dinesh; Seth, Siddharth; Srinivasan, Kannan; Levis, Philip; Katti, Sachin; Sinha, Prasun

    2011-01-01

    This paper presents a full duplex radio design using signal inversion and adaptive cancellation. Signal inversion uses a simple design based on a balanced/unbalanced (Balun) transformer. This new design, unlike prior work, supports wideband and high power systems. In theory, this new design has no limitation on bandwidth or power. In practice, we find that the signal inversion technique alone can cancel at least 45dB across a 40MHz bandwidth. Further, combining signal inversion cancellation with cancellation in the digital domain can reduce self-interference by up to 73dB for a 10MHz OFDM signal. This paper also presents a full duplex medium access control (MAC) design and evaluates it using a testbed of 5 prototype full duplex nodes. Full duplex reduces packet losses due to hidden terminals by up to 88%. Full duplex also mitigates unfair channel allocation in AP-based networks, increasing fairness from 0.85 to 0.98 while improving downlink throughput by 110% and uplink throughput by 15%. These experimental results show that a re- design of the wireless network stack to exploit full duplex capability can result in significant improvements in network performance. © 2011 ACM.

  12. Energy balance and deformation mechanisms of duplexes

    Science.gov (United States)

    Mitra, Gautam; Boyer, Steven E.

    A duplex consists of a series of imbricate faults that are asymptotic to a roof thrust and a floor thrust. Depending on the final orientations of the imbricate faults and the final position of the branch lines, a duplex may be hinterland-dipping, foreland-dipping, or an antiformal stack. The exact geometry depends on various factors such as the initial dimensions of the individual slices (horses), their lithology, the amount of displacement (normalized to size of horse) on each fault, and the mechanics of movement along each fault. The energy required in duplex formation can be determined by calculating the total work involved in emplacing each horse: this is given by where W t=W p+W b+W g+W iWp is the work involved in initiating and propagating a fracture. Wb is the work involved in basal sliding, which may be frictional or some form of ductile flow, Wg is the work done against gravity during the emplacement of the horse, and Wi is the work involved in the internal deformation of the horse. By calculating and comparing these work terms it is possible to predict the conditions under which the different types of duplexes will form. Normally, the development of a hinterland-dipping duplex is most likely. However, if deformation conditions are favorable, displacements on individual imbricate faults may be very large compared to the size of the horses, leading to the formation of either antiformal stacks or foreland-dipping duplexes.

  13. Non-invasive assessment of peripheral arterial disease: Automated ankle brachial index measurement and pulse volume analysis compared to duplex scan.

    Science.gov (United States)

    Lewis, Jane Ea; Williams, Paul; Davies, Jane H

    2016-01-01

    This cross-sectional study aimed to individually and cumulatively compare sensitivity and specificity of the (1) ankle brachial index and (2) pulse volume waveform analysis recorded by the same automated device, with the presence or absence of peripheral arterial disease being verified by ultrasound duplex scan. Patients (n=205) referred for lower limb arterial assessment underwent ankle brachial index measurement and pulse volume waveform recording using volume plethysmography, followed by ultrasound duplex scan. The presence of peripheral arterial disease was recorded if ankle brachial index 50% was evident with ultrasound duplex scan. Outcome measure was agreement between the measured ankle brachial index and interpretation of pulse volume waveform for peripheral arterial disease diagnosis, using ultrasound duplex scan as the reference standard. Sensitivity of ankle brachial index was 79%, specificity 91% and overall accuracy 88%. Pulse volume waveform sensitivity was 97%, specificity 81% and overall accuracy 85%. The combined sensitivity of ankle brachial index and pulse volume waveform was 100%, specificity 76% and overall accuracy 85%. Combining these two diagnostic modalities within one device provided a highly accurate method of ruling out peripheral arterial disease, which could be utilised in primary care to safely reduce unnecessary secondary care referrals.

  14. Ultrasound -- Pelvis

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    Full Text Available ... Radiation Therapy for Gynecologic Cancers Radiation Therapy for Prostate Cancer top of page This page was reviewed on ... Abdomen Children's (Pediatric) Ultrasound - Abdomen Obstetric Ultrasound Ultrasound - Prostate Kidney and Bladder Stones Abnormal Vaginal Bleeding ... Images related to Ultrasound - Pelvis Sponsored by Please ...

  15. Ultrasound -- Pelvis

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    Full Text Available ... endometrial polyps fibroids cancer, especially in patients with abnormal uterine bleeding Some physicians also use 3-D ultrasound or ... Obstetric Ultrasound Ultrasound - Prostate Kidney and Bladder Stones Abnormal Vaginal Bleeding Ovarian Cancer Images related to Ultrasound - Pelvis Sponsored ...

  16. Harvesting full-duplex rate gains in cellular networks with half-duplex user terminals

    KAUST Repository

    Alammouri, Ahmad; Elsawy, Hesham; Alouini, Mohamed-Slim

    2016-01-01

    Full-Duplex (FD) transceivers may be expensive in terms of complexity, power consumption, and price to be implemented in all user terminals. Therefore, techniques to exploit in-band full-duplex communication with FD base stations (BSs) and half

  17. Sonomammography: An atlas of comparative breast ultrasound

    International Nuclear Information System (INIS)

    Guyer, B.P.; Dewsbury, K.C.

    1987-01-01

    This atlas of breast ultrasound is extensively illustrated and provides a short analytical text before each group of pathologies. Although based on B-scan techniques, there are numerous comparisons with sector scans and linear array scans. X-ray mammography and breast ultrasound is analyzed, based upon 2000 sonomammograms, showing how a more accurate pre-operation assessment can be made, and how unnecessary surgery can be reduced. Major features of this atlas include a detailed analysis of the appearances of breast lesions, extensive illustrations of the various pathologies (generally confirmed histologically), a close comparison of ultrasound with x-ray mammography, and illustrations of lesions by different ultrasound techniques

  18. Internal Carotid Artery Hypoplasia: Role of Color-Coded Carotid Duplex Sonography.

    Science.gov (United States)

    Chen, Pei-Ya; Liu, Hung-Yu; Lim, Kun-Eng; Lin, Shinn-Kuang

    2015-10-01

    The purpose of this study was to determine the role of color-coded carotid duplex sonography for diagnosis of internal carotid artery hypoplasia. We retrospectively reviewed 25,000 color-coded carotid duplex sonograms in our neurosonographic database to establish more diagnostic criteria for internal carotid artery hypoplasia. A definitive diagnosis of internal carotid artery hypoplasia was made in 9 patients. Diagnostic findings on color-coded carotid duplex imaging include a long segmental small-caliber lumen (52% diameter) with markedly decreased flow (13% flow volume) in the affected internal carotid artery relative to the contralateral side but without intraluminal lesions. Indirect findings included markedly increased total flow volume (an increase of 133%) in both vertebral arteries, antegrade ipsilateral ophthalmic arterial flow, and a reduced vessel diameter with increased flow resistance in the ipsilateral common carotid artery. Ten patients with distal internal carotid artery dissection showed a similar color-coded duplex pattern, but the reductions in the internal and common carotid artery diameters and increase in collateral flow from the vertebral artery were less prominent than those in hypoplasia. The ipsilateral ophthalmic arterial flow was retrograde in 40% of patients with distal internal carotid artery dissection. In addition, thin-section axial and sagittal computed tomograms of the skull base could show the small diameter of the carotid canal in internal carotid artery hypoplasia and help distinguish hypoplasia from distal internal carotid artery dissection. Color-coded carotid duplex sonography provides important clues for establishing a diagnosis of internal carotid artery hypoplasia. A hypoplastic carotid canal can be shown by thin-section axial and sagittal skull base computed tomography to confirm the final diagnosis. © 2015 by the American Institute of Ultrasound in Medicine.

  19. Buffer management in wireless full-duplex systems

    KAUST Repository

    Bouacida, Nader; Showail, Ahmad; Shihada, Basem

    2015-01-01

    , we address the problem of buffer management in full-duplex networks by using Wireless Queue Management (WQM), which is an active queue management technique for wireless networks. Our solution is based on Relay Full-Duplex MAC (RFD

  20. On full duplex Gaussian relay channels with self-interference

    KAUST Repository

    Behboodi, Arash; Chaaban, Anas; Mathar, Rudolf; Alouini, Mohamed-Slim

    2016-01-01

    Self interference (SI) in full duplex (FD) systems is the interference caused by the transmission stream on the reception stream. Being one of the main restrictive factors for performance of practical full duplex systems, however, not too much

  1. Full-Duplex Relay Selection in Cognitive Underlay Networks

    KAUST Repository

    Khafagy, Mohammad Galal; Alouini, Mohamed-Slim; Aissa, Sonia

    2017-01-01

    In this work, we analyze the performance of full-duplex relay selection (FDRS) in spectrum-sharing networks. Contrary to half-duplex relaying, full-duplex relaying (FDR) enables simultaneous listening/forwarding at the secondary relay(s), thereby

  2. [Preoperative structured patient education].

    Science.gov (United States)

    Lamarche, D

    1993-04-01

    This article describes the factors that motivated the nursing staff of the cardiac surgery unit at the Royal Victoria Hospital in Montreal, to revise their preoperative teaching program. The motivating factors described are the length of the preoperative waiting period; the level of preoperative anxiety; the decreased length of hospital stay; the dissatisfaction of the nursing staff with current patient teaching practices; and the lack of available resources. The reorganization of the teaching program was based upon the previously described factors combined with a review of the literature that demonstrated the impact of preoperative anxiety, emotional support and psycho-educational interventions upon the client's recovery. The goals of the new teaching program are to provide the client and the family with cognitive and sensory information about the client's impending hospitalization, chronic illness and necessary lifestyle modifications. The program consists of a system of telephone calls during the preoperative waiting period; a videotape viewing; a tour of the cardiac surgery unit; informal discussion groups; and the availability of nursing consultation to decrease preoperative anxiety. The end result of these interventions is more time for client support and integration of necessary information by the client and family. This kind of program has the potential to provide satisfaction at many levels by identifying client's at risk; increasing client knowledge; increasing support; decreasing anxiety during the preoperative waiting period; and decreasing the length of hospital stay. The nursing staff gained a heightened sense of accomplishment because the program was developed according to the nursing department's philosophy, which includes primary nursing.(ABSTRACT TRUNCATED AT 250 WORDS)

  3. Ultrasound -- Pelvis

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    Full Text Available ... diagnose symptoms experienced by women such as: pelvic pain abnormal vaginal bleeding other menstrual problems Ultrasound exams ... pelvic ultrasound can help evaluate: pelvic masses pelvic pain ambiguous genitalia and anomalies of pelvic organs early ...

  4. Ultrasound -- Pelvis

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    Full Text Available ... size, shape and consistency (whether the object is solid or filled with fluid). In medicine, ultrasound is ... ultrasound, measures the direction and speed of blood cells as they move through vessels. The movement of ...

  5. Prostate Ultrasound

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    Full Text Available ... pictures of a man’s prostate gland and to help diagnose symptoms such as difficulty urinating or an ... Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. Prostate ultrasound, ...

  6. Ultrasound -- Pelvis

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    Full Text Available ... by women such as: pelvic pain abnormal vaginal bleeding other menstrual problems Ultrasound exams also help identify: ... fibroids cancer, especially in patients with abnormal uterine bleeding Some physicians also use 3-D ultrasound or ...

  7. Ultrasound -- Pelvis

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    Full Text Available ... internal organs, as well as blood flowing through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. There are three types of pelvic ultrasound: abdominal ( transabdominal ) vaginal ( transvaginal / endovaginal ) ...

  8. Ultrasound -- Pelvis

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    Full Text Available ... There are three types of pelvic ultrasound: abdominal, vaginal (for women), and rectal (for men). These exams ... are three types of pelvic ultrasound: abdominal ( transabdominal ) vaginal ( transvaginal / endovaginal ) for women rectal ( transrectal ) for men ...

  9. Ultrasound -- Pelvis

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    Full Text Available ... the procedure? In women, a pelvic ultrasound is most often performed to evaluate the: uterus cervix ovaries ... page How is the procedure performed? Transabdominal: For most ultrasound exams, you will be positioned lying face- ...

  10. Ultrasound -- Pelvis

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    Full Text Available ... is used to evaluate the: bladder seminal vesicles prostate Transrectal ultrasound, a special study usually done to provide detailed evaluation of the prostate gland, involves inserting a specialized ultrasound transducer into ...

  11. Ultrasound -- Pelvis

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  12. Prostate Ultrasound

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    Full Text Available ... top of page What are the benefits vs. risks? Benefits Ultrasound is widely available, easy-to-use ... procedures such as needle biopsies and fluid aspiration. Risks For standard diagnostic ultrasound , there are no known ...

  13. Ultrasound -- Pelvis

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    Full Text Available ... insertion. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... modality for the diagnosis and monitoring of pregnant women and their unborn babies. Ultrasound provides real-time ...

  14. Ultrasound -- Pelvis

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    Full Text Available ... ovarian cysts and uterine fibroids ovarian or uterine cancers A transvaginal ultrasound is usually performed to view the endometrium (the lining of the uterus) and the ovaries. Transvaginal ultrasound also evaluates the myometrium (muscular walls ...

  15. Prostate Ultrasound

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    Full Text Available ... those sound waves to create an image. Ultrasound examinations do not use ionizing radiation (as used in ... abnormal masses, such as tumors. In an ultrasound examination, a transducer both sends the sound waves into ...

  16. Ultrasound -- Pelvis

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    Full Text Available ... needles are used to extract a sample of cells from organs for laboratory testing. Doppler ultrasound images ... ultrasound, measures the direction and speed of blood cells as they move through vessels. The movement of ...

  17. Ultrasound -- Pelvis

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    Full Text Available ... image. Ultrasound examinations do not use ionizing radiation (as used in x-rays ), thus there is no ... structure and movement of the body's internal organs, as well as blood flowing through blood vessels. Ultrasound ...

  18. Prostate Ultrasound

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    Full Text Available ... to-use and less expensive than other imaging methods. Ultrasound imaging uses no ionizing radiation. Ultrasound scanning ... radiation oncology provider in your community, you can search the ACR-accredited facilities database . This website does ...

  19. Ultrasound -- Pelvis

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    Full Text Available ... Ultrasound is the preferred imaging modality for the diagnosis and monitoring of pregnant women and their unborn ... sexes without x-ray exposure. Risks For standard diagnostic ultrasound , there are no known harmful effects on ...

  20. Prostate Ultrasound

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    Full Text Available ... patient. Because ultrasound images are captured in real-time, they can show the structure and movement of ... test result. difficulty urinating. Because ultrasound provides real-time images, it also can be used to guide ...

  1. Ultrasound -- Pelvis

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  2. Prostate Ultrasound

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  3. Ultrasound -- Pelvis

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    Full Text Available ... Imaging? Ultrasound waves are disrupted by air or gas; therefore ultrasound is not an ideal imaging technique ... page Additional Information and Resources RTAnswers.org Radiation Therapy for Gynecologic Cancers Radiation Therapy for Prostate Cancer ...

  4. Prostate Ultrasound

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    Full Text Available ... ultrasound images are captured in real-time, they can show the structure and movement of the body's ... Because ultrasound provides real-time images, it also can be used to guide procedures such as needle ...

  5. Prostate Ultrasound

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    Full Text Available ... of page What will I experience during and after the procedure? Ultrasound exams in which the transducer ... in the sperm or urine following the procedure. After an ultrasound examination, you should be able to ...

  6. Ultrasound -- Pelvis

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    Full Text Available ... investigation of the uterine cavity . Three-dimensional (3-D) ultrasound permits evaluation of the uterus and ovaries ... abnormal uterine bleeding Some physicians also use 3-D ultrasound or sonohysterography for patients with infertility. In ...

  7. Prostate Ultrasound

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    Full Text Available ... and produces pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound ... from the probe through the gel into the body. The transducer collects the sounds that bounce back ...

  8. Ultrasound -- Pelvis

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    Full Text Available ... and produces pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound ... from the probe through the gel into the body. The transducer collects the sounds that bounce back ...

  9. Ultrasound -- Pelvis

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    Full Text Available ... object is solid or filled with fluid). In medicine, ultrasound is used to detect changes in appearance, ... have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media Sonohysterography Ultrasound - ...

  10. Obstetrical Ultrasound

    Science.gov (United States)

    ... heartbeat can be seen as an ongoing ultrasound movie. Ultrasound devices also use Doppler, a special application ... the possible charges you will incur. Web page review process: This Web page is reviewed regularly by ...

  11. Ultrasound -- Pelvis

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    Full Text Available ... insertion. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media Sonohysterography Ultrasound - ...

  12. Ultrasound -- Pelvis

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    Full Text Available ... menstrual problems Ultrasound exams also help identify: palpable masses such as ovarian cysts and uterine fibroids ovarian ... In children, pelvic ultrasound can help evaluate: pelvic masses pelvic pain ambiguous genitalia and anomalies of pelvic ...

  13. Prostate Ultrasound

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    Full Text Available ... Ultrasound is safe, noninvasive, and does not use ionizing radiation. This procedure requires little to no special preparation. ... create an image. Ultrasound examinations do not use ionizing radiation (as used in x-rays ), thus there is ...

  14. Ultrasound -- Pelvis

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    Full Text Available ... Ultrasound is safe, noninvasive and does not use ionizing radiation. This procedure requires little to no special preparation. ... create an image. Ultrasound examinations do not use ionizing radiation (as used in x-rays ), thus there is ...

  15. Ultrasound -- Pelvis

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    Full Text Available ... and development of an embryo or fetus during pregnancy. See the Obstetrical Ultrasound page for more information . ... object is solid or filled with fluid). In medicine, ultrasound is used to detect changes in appearance, ...

  16. Ultrasound -- Pelvis

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    Full Text Available ... most ultrasound exams, you will be positioned lying face-up on an examination table that can be ... region of the prostate. A biopsy will add time to the procedure. If a Doppler ultrasound study ...

  17. Ultrasound -- Pelvis

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    Full Text Available ... ultrasound: abdominal, vaginal (for women), and rectal (for men). These exams are frequently used to evaluate the ... vaginal ( transvaginal / endovaginal ) for women rectal ( transrectal ) for men A Doppler ultrasound exam may be part of ...

  18. Measuring secondary phases in duplex stainless steels

    Science.gov (United States)

    Calliari, I.; Brunelli, K.; Dabalà, M.; Ramous, E.

    2009-01-01

    The use of duplex stainless steels is limited by their susceptibility to the formation of dangerous intermetallic phases resulting in detrimental effects on impact toughness and corrosion resistance. This precipitation and the quantitative determinations of the phases have received considerable attention and different precipitation sequences (σ phase, χ phase, and carbides) have been suggested. This study investigates the phase transformation during continuous cooling and isothermal treatments in commercial duplex stainless steel grades and the effects on alloy properties, and compares the most common techniques of analysis.

  19. Full-duplex optical communication system

    Science.gov (United States)

    Shay, Thomas M. (Inventor); Hazzard, David A. (Inventor); Horan, Stephen (Inventor); Payne, Jason A. (Inventor)

    2004-01-01

    A method of full-duplex electromagnetic communication wherein a pair of data modulation formats are selected for the forward and return data links respectively such that the forward data electro-magnetic beam serves as a carrier for the return data. A method of encoding optical information is used wherein right-hand and left-hand circular polarizations are assigned to optical information to represent binary states. An application for an earth to low earth orbit optical communications system is presented which implements the full-duplex communication and circular polarization keying modulation format.

  20. Immediate preoperative enteral nutrition (preoperative enteral nutrition

    Directory of Open Access Journals (Sweden)

    Lađević Nebojša

    2017-01-01

    Full Text Available Nutritional support of surgical patients is a necessary part of the treatment. It alone cannot cure the disease but it significantly affects the recovery of patients and supports surgical interventions. Patients in malnutrition have shown to have significantly more postoperative infectious and non-infectious complications. This significantly prolongs treatment time and increases costs. However, there is one fact that cannot be expressed in money, which is the patient's impression of the surgical intervention. Adequate preoperative patient support, based on the intake of liquid nutritive solutions, reduces preoperative stress and deflects the metabolic response. Now, it is recommended for adults and children older than one year to drink clear liquid up to 2 hours before induction in anesthesia. Appropriate enteral nutrition has a significant place in the postoperative recovery of patients. Enteral nutrition is reducing complications, mainly infectious complications because the function of the digestive system as one large immune system is preserved. Perioperative enteral nutrition is a necessary part of the modern treatment of surgical patients. In addition to the significant effect on the occurrence of postoperative complications, it is also important that this type of diet improves the psychological status of patients.

  1. Ultrasound -- Pelvis

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    Full Text Available ... transducer sends out high-frequency sound waves (that the human ear cannot hear) into the body and then ... ultrasound , there are no known harmful effects on humans. top of page What are the limitations of Pelvic Ultrasound Imaging? Ultrasound waves are ...

  2. Preoperative ultrasonography and prediction of technical difficulties during laparoscopic cholecystectomy.

    Science.gov (United States)

    Daradkeh, S S; Suwan, Z; Abu-Khalaf, M

    1998-01-01

    A prospective study was carried out to investigate the value of preoperative ultrasound findings for predicting difficulties encountered during laparoscopic cholecystectomy (LC). Altogether 160 consecutive patients with symptomatic gallbladder (GB) disease (130 females, 30 males) referred to the Jordan University Hospital were recruited for the purpose of this study. All patients underwent detailed ultrasound examination 24 hours prior to LC. The overall difficulty score (ODS), as a dependent variable, was based on the following operative parameters: duration of surgery, bleeding, dissection of Calot's triangle, dissection of gallbladder wall, adhesions, spillage of bile, spillage of stone, and difficulty of gallbladder extraction. Multiple regression analysis was used to assess the significance of the following preoperative ultrasound variables (independent) for predicting the variation in the ODS: size of the GB, number of GB stones, size of stones, location of GB stones, thickness of GB wall, common bile duct (CBD) diameter, and liver size. Only thickness of GB wall and CBD diameter were found to be significant predictors of the variation in the ODS (adjusted R2 = 0.25). We conclude that the preoperative ultrasound examination is of value for predicting difficulties encountered during LC, but it is not the sole predictor.

  3. Backbone conformation affects duplex initiation and duplex propagation in hybridisation of synthetic H-bonding oligomers.

    Science.gov (United States)

    Iadevaia, Giulia; Núñez-Villanueva, Diego; Stross, Alexander E; Hunter, Christopher A

    2018-06-06

    Synthetic oligomers equipped with complementary H-bond donor and acceptor side chains form multiply H-bonded duplexes in organic solvents. Comparison of the duplex forming properties of four families of oligomers with different backbones shows that formation of an extended duplex with three or four inter-strand H-bonds is more challenging than formation of complexes that make only two H-bonds. The stabilities of 1 : 1 complexes formed between length complementary homo-oligomers equipped with either phosphine oxide or phenol recognition modules were measured in toluene. When the backbone is very flexible (pentane-1,5-diyl thioether), the stability increases uniformly by an order of magnitude for each additional base-pair added to the duplex: the effective molarities for formation of the first intramolecular H-bond (duplex initiation) and subsequent intramolecular H-bonds (duplex propagation) are similar. This flexible system is compared with three more rigid backbones that are isomeric combinations of an aromatic ring and methylene groups. One of the rigid systems behaves in exactly the same way as the flexible backbone, but the other two do not. For these systems, the effective molarity for formation of the first intramolecular H-bond is the same as that found for the other two backbones, but additional H-bonds are not formed between the longer oligomers. The effective molarities are too low for duplex propagation in these systems, because the oligomer backbones cannot adopt conformations compatible with formation of an extended duplex.

  4. Ultra-short silicon MMI duplexer

    Science.gov (United States)

    Yi, Huaxiang; Huang, Yawen; Wang, Xingjun; Zhou, Zhiping

    2012-11-01

    The fiber-to-the-home (FTTH) systems are growing fast these days, where two different wavelengths are used for upstream and downstream traffic, typically 1310nm and 1490nm. The duplexers are the key elements to separate these wavelengths into different path in central offices (CO) and optical network unit (ONU) in passive optical network (PON). Multimode interference (MMI) has some benefits to be a duplexer including large fabrication tolerance, low-temperature dependence, and low-polarization dependence, but its size is too large to integrate in conventional case. Based on the silicon photonics platform, ultra-short silicon MMI duplexer was demonstrated to separate the 1310nm and 1490nm lights. By studying the theory of self-image phenomena in MMI, the first order images are adopted in order to keep the device short. A cascaded MMI structure was investigated to implement the wavelength splitting, where both the light of 1310nm and 1490nm was input from the same port, and the 1490nm light was coupling cross the first MMI and output at the cross-port in the device while the 1310nm light was coupling through the first and second MMI and output at the bar-port in the device. The experiment was carried on with the SOI wafer of 340nm top silicon. The cascaded MMI was investigated to fold the length of the duplexer as short as 117μm with the extinct ratio over 10dB.

  5. Duplex Design Project: Science Pilot Test.

    Science.gov (United States)

    Center for Research on Evaluation, Standards, and Student Testing, Los Angeles, CA.

    Work is reported towards the completion of a prototype duplex-design assessment instrument for grade-12 science. The student course-background questionnaire and the pretest section of the two-stage instrument that was developed were administered to all 134 12th-grade students at St. Clairsville High School (Ohio). Based on the information obtained…

  6. 99Tcm-DTPA renography in evaluating the function of duplex kidneys in pediatric patients

    International Nuclear Information System (INIS)

    Zhang Lixia; Wang Xiaoming; Chen Jinyan; Su Junmei

    2013-01-01

    Objective: To study the value of 99 Tc m -DTPA dynamic renography in evaluating the function of duplex kidneys in pediatric patients. Methods: Twenty-five pediatric patients with duplex kidneys diagnosed by ultrasound or MR urography (MRU) were included (9 males, 16 females; mean age:(23.80 ± 20.97) months, range: 2-72 months). Twenty patients (9 males,11 females; mean age: (32.95 ± 23.58) months, range: 2-72 months) with urinary tract infection but without duplex kidneys confirmed by ultrasound or MRU were chosen as control group during the same period of this study. All patients and controls were divided into two subgroups according to their ages (group Ⅰ, 0-24 months; group Ⅱ, 25-72 months). The research was approved by the ethics committee, and all patients' parents (or guardians) signed informed consents. The time-activity curve was generated on the dynamic imaging data automatically with GFR calculated. The uptake rates of the upper and lower moieties were measured by drawing the corresponding ROIs in the duplex kidney. Dunnett-t test was used for statistical analysis. Results: There were 25 patients with 26 duplex kidneys (1 case bilateral), 16 on the left and 10 on the right. The time-activity curve of 6 cases was normal, 9 with continuously upward type, 4 with high level plateau type, 2 with parabolic type and 5 with low level plateau type. There were 19 abnormal kidneys in group Ⅰ and 7 in group Ⅱ, and 20 kidneys in each control subgroup. The GFR of patients with normal renography was (78.81 ± 15.97) ml/min (group Ⅰ) and (64.68 ± 11.15) ml/min (group Ⅱ), continuously upward type was (72.11 ±22.76) ml/min (group Ⅰ) and (63.41 ± 16.42) ml/min (group Ⅱ), high level plateau and parabolic types were (68.74 ± 16.17) ml/min and (65.26 ± 15.27) ml/min in group Ⅰ, respectively. There was no statistically significant difference between the GFR of different renography type groups and that of the controls (group Ⅰ: (79.35 ±13.31) ml

  7. [Preoperative fasting. An update].

    Science.gov (United States)

    Spies, C D; Breuer, J P; Gust, R; Wichmann, M; Adolph, M; Senkal, M; Kampa, U; Weissauer, W; Schleppers, A; Soreide, E; Martin, E; Kaisers, U; Falke, K J; Haas, N; Kox, W J

    2003-11-01

    In Germany the predominant standard of preoperative care for elective surgery is fasting after midnight, with the aim of reducing the risk of pulmonary aspiration. However, for the past several years the scientific evidence supporting such a practice has been challenged. Experimental and clinical studies prove a reliable gastric emptying within 2 h suggesting that, particularly for limited intake of clear fluids up to 2 h preoperatively, there would be no increased risk for the patient. In addition, the general incidence of pulmonary aspiration during general anaesthesia (before induction, during surgery and during recovery) is extremely low, has a good prognosis and is more a consequence of insufficient airway protection and/or inadequate anaesthetic depth rather than due to the patient's fasting state. Therefore, primarily to decrease perioperative discomfort for patients, several national anaesthesia societies have changed their guidelines for preoperative fasting. They recommend a more liberal policy regarding per os intake of both liquid and solid food, with consideration of certain conditions and contraindications. The following article reviews the literature and gives an overview of the scientific background on which the national guidelines are based. The intention of this review is to propose recommendations for preoperative fasting regarding clear fluids for Germany as well.

  8. Artificial neural network aided non-invasive grading evaluation of hepatic fibrosis by duplex ultrasonography

    Directory of Open Access Journals (Sweden)

    Zhang Li

    2012-06-01

    Full Text Available Abstract Background Artificial neural networks (ANNs are widely studied for evaluating diseases. This paper discusses the intelligence mode of an ANN in grading the diagnosis of liver fibrosis by duplex ultrasonogaphy. Methods 239 patients who were confirmed as having liver fibrosis or cirrhosis by ultrasound guided liver biopsy were investigated in this study. We quantified ultrasonographic parameters as significant parameters using a data optimization procedure applied to an ANN. 179 patients were typed at random as the training group; 60 additional patients were consequently enrolled as the validating group. Performance of the ANN was evaluated according to accuracy, sensitivity, specificity, Youden’s index and receiver operating characteristic (ROC analysis. Results 5 ultrasonographic parameters; i.e., the liver parenchyma, thickness of spleen, hepatic vein (HV waveform, hepatic artery pulsatile index (HAPI and HV damping index (HVDI, were enrolled as the input neurons in the ANN model. The sensitivity, specificity and accuracy of the ANN model for quantitative diagnosis of liver fibrosis were 95.0%, 85.0% and 88.3%, respectively. The Youden’s index (YI was 0.80. Conclusions The established ANN model had good sensitivity and specificity in quantitative diagnosis of hepatic fibrosis or liver cirrhosis. Our study suggests that the ANN model based on duplex ultrasound may help non-invasive grading diagnosis of liver fibrosis in clinical practice.

  9. Interventions for preoperative smoking cessation

    DEFF Research Database (Denmark)

    Møller, A; Villebro, N

    2005-01-01

    Smokers have a substantially increased risk of intra- and postoperative complications. Preoperative smoking intervention may be effective in decreasing this incidence. The preoperative period may be a well chosen time to offer smoking cessation interventions due to increased patient motivation....

  10. Diagnostic Ultrasound in Colorectal Cancer

    DEFF Research Database (Denmark)

    Rafaelsen, Søren Rafael

    2014-01-01

    SUMMARYBackground and purpose Colorectal cancer is a common disease in Denmark with considerable morbidity and mortality. Although survival in recent years has improved, Denmark still has the lowest 5-year survival compared to the other Nordic countries. The treatment of patients depends on local...... the potential to contribute to the staging of colorectal cancer. The purpose of these studies was to determine the usefulness of ultrasound diagnostics in patients with colorectal cancer.The purpose of the TRUS studies was to compare staging of rectal carcinomas using digital rectal exploration...... of 295 patients with primary colorectal cancer we found a sensitivity of preoperative ultrasound, surgical exploration, and intraoperative ultrasound of 70%, 84%, and 97%, respectively, based on a patient-by-patient comparison (p

  11. Relationships between duplex findings and quality of life in long-term follow-up of patients treated for chronic venous disease.

    Science.gov (United States)

    Huang, Ying; Gloviczki, Peter

    2016-03-01

    Relationships between duplex findings and data on health-related quality of life (QoL) to assess long-term results of treatment of varicose veins and chronic venous insufficiency (CVI) are not well known. The goal of this review was to correlate duplex findings and QoL assessments in clinical studies with long-term follow-up. A review of the English language literature on PUBMED revealed 17 clinical studies, including 9 randomized controlled trials (RCTs), 6 prospective, and 2 retrospective studies that included patients with at least 5-year follow-up after endovenous laser ablation (EVLA), radiofrequency ablation (RFA), ultrasound-guided foam sclerotherapy (UGFS), and traditional superficial venous surgery. At 5 years, great saphenous vein (GSV) occlusion rate on duplex ultrasound ranged from 66% to 82% for EVLA, from 62% to 92% for RFA, from 41% to 58% for UGFS and from 54% to 85% for surgery. Freedom from GSV reflux rates were 82% and 84%, respectively for EVLA and surgery, and ranged between 84% and 95% for RFA. Significant improvements were observed in several domains of generic QoL and in most domains of venous disease-specific QoL, irrespective of the treatment. In at least one RCT, CIVIQ scores correlated well with abnormal duplex findings in patients who underwent treatment with UGFS. In another RCT, long-term AVVQ was significantly better after surgery as compared with UGFS similar to results of duplex findings. Analysis of the available literature confirmed that all four techniques were effective in the abolishment of reflux or obliteration of the GSV. Moreover, well-designed RCTs with large sample size are needed to produce robust long-term data on clinical outcome after treatment of varicose veins and CVI and to better understand the relationships between duplex-derived data and QoL assessments. © The Author(s) 2016.

  12. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... internal organs, as well as blood flowing through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. ...

  13. Preoperative bone scans

    International Nuclear Information System (INIS)

    Charkes, N.D.; Malmud, L.S.; Caswell, T.; Goldman, L.; Hall, J.; Lauby, V.; Lightfoot, W.; Maier, W.; Rosemond, G.

    1975-01-01

    Strontium nitrate Sr-87m bone scans were made preoperatively in a group of women with suspected breast cancer, 35 of whom subsequently underwent radical mastectomy. In 3 of the 35 (9 percent), the scans were abnormal despite the absence of clinical or roentgenographic evidence of metastatic disease. All three patients had extensive axillary lymph node involvement by tumor, and went on to have additional bone metastases, from which one died. Roentgenograms failed to detect the metastases in all three. Occult bone metastases account in part for the failure of radical mastectomy to cure some patients with breast cancer. It is recommended that all candidates for radical mastectomy have a preoperative bone scan. (U.S.)

  14. Ultrasound and multidetector computed tomography of mandibular ...

    African Journals Online (AJOL)

    Because of local invasivity and high metastatic potential, preoperative imaging evaluation of mandibular region and tumoral staging is essential along with biopsy sampling. The present manuscript describes the ultrasound and computed tomographic imaging findings of mandibular gland adenocarcinoma in two dogs and ...

  15. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... inserted into a man's rectum to view the prostate. Transvaginal ultrasound. The transducer is inserted into a ... Stenting Ultrasound-Guided Breast Biopsy Obstetric Ultrasound Ultrasound - Prostate Biopsies - Overview Images related to General Ultrasound Videos ...

  16. General Ultrasound Imaging

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    Full Text Available ... News Physician Resources Professions Site Index A-Z General Ultrasound Ultrasound imaging uses sound waves to produce ... the limitations of General Ultrasound Imaging? What is General Ultrasound Imaging? Ultrasound is safe and painless, and ...

  17. Thermal ageing of duplex stainless steels

    International Nuclear Information System (INIS)

    Massoud, J.P.; Van Duysen, J.C.; Zacharie, G.; Auger, P.; Danoix, F.

    1992-03-01

    The evolution of the mechanical properties of Mobearing anf Mo-free cast duplex stainless steels, induced by long term ageing in the range 300-400 deg C, has been studied in relation with the evolution of their microstructure. The unmixing of the ferritic Fe-Cr-Ni, solid solution by three-dimensional (sponge-like) spinodal decomposition and the precipitation of intermetallic G-phase particles are the main characteristics of this microstructural evolution

  18. Development of a lean duplex stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Liljas, M.; Johansson, P.; Liu Hui-Ping; Olsson, C.O.A. [Avesta Research Centre, Avesta (Sweden). Outokumpu Stainless

    2008-06-15

    The classic series of duplex stainless steels shows very high corrosion resistance and can be used for very demanding applications. A new lean duplex steel, LDX 2101 {sup registered} (EN 1.4162, UNS S32101), has been developed with corrosion resistance on a par with standard austenitic grades. Application areas include: structural components, chemical industry, tanks and containers. The steel was designed to have equal amounts of ferrite and austenite in annealed condition and with an austenite that is stable against strain-induced martensite. Thanks to its high nitrogen content, the steel has a fast austenite reformation when subjected to thermal cycling, e.g. welding. Unlike conventional duplex grades, the formation of intermetallic phase is very sluggish, although precipitation of nitrides and carbides has a certain impact on material properties after exposure in the temperature range 600 to 800 C. The precipitation behaviour after different isothermal treatments is described and its influence on different product properties is shown. A good agreement was found between impact toughness and corrosion resistance for a wide range of thermal treatments. (orig.)

  19. Joint duplex mode selection, channel allocation, and power control for full-duplex cognitive femtocell networks

    Directory of Open Access Journals (Sweden)

    Mingjie Feng

    2015-02-01

    Full Text Available In this paper, we aim to maximize the sum rate of a full-duplex cognitive femtocell network (FDCFN as well as guaranteeing the quality of service (QoS of users in the form of a required signal to interference plus noise ratios (SINR. We first consider the case of a pair of channels, and develop optimum-achieving power control solutions. Then, for the case of multiple channels, we formulate joint duplex model selection, power control, and channel allocation as a mixed integer nonlinear problem (MINLP, and propose an iterative framework to solve it. The proposed iterative framework consists of a duplex mode selection scheme, a near-optimal distributed power control algorithm, and a greedy channel allocation algorithm. We prove the convergence of the proposed iterative framework as well as a lower bound for the greedy channel allocation algorithm. Numerical results show that the proposed schemes effectively improve the sum rate of FDCFNs.

  20. Characterization of thermal aging of duplex stainless steel by SQUID

    International Nuclear Information System (INIS)

    Isobe, Y.; Kamimura, A.; Aoki, K.; Nakayasu, F.

    1995-01-01

    Thermal aging is a growing concern for long-term-aged duplex stainless steel piping in nuclear power plants. Superconducting QUantum Interference Device (SQUID) was used for the detection of thermal aging of SUS329 rolled duplex stainless steel and SCS16 cast duplex stainless steel. It was found that the SQUID output signal pattern in the presence of AC magnetic field applied to the specimen was sensitive to the changes in electromagnetic properties due to thermal aging

  1. Full-Duplex MIMO Small-Cell Networks: Performance Analysis

    OpenAIRE

    Atzeni, Italo; Kountouris, Marios

    2015-01-01

    Full-duplex small-cell relays with multiple antennas constitute a core element of the envisioned 5G network architecture. In this paper, we use stochastic geometry to analyze the performance of wireless networks with full-duplex multiple-antenna small cells, with particular emphasis on the probability of successful transmission. To achieve this goal, we additionally characterize the distribution of the self-interference power of the full-duplex nodes. The proposed framework reveals useful ins...

  2. Electron Beam Welding of Duplex Steels with using Heat Treatment

    Science.gov (United States)

    Schwarz, Ladislav; Vrtochová, Tatiana; Ulrich, Koloman

    2010-01-01

    This contribution presents characteristics, metallurgy and weldability of duplex steels with using concentrated energy source. The first part of the article describes metallurgy of duplex steels and the influence of nitrogen on their solidification. The second part focuses on weldability of duplex steels with using electron beam aimed on acceptable structure and corrosion resistance performed by multiple runs of defocused beam over the penetration weld.

  3. Prostate Ultrasound

    Medline Plus

    Full Text Available ... be able to give a clearer picture of soft tissues that do not show up well on x-ray images. Ultrasound causes no health problems and may be repeated as often as is necessary if medically indicated. Ultrasound provides real-time imaging, making it a good tool for guiding ...

  4. Prostate Ultrasound

    Science.gov (United States)

    ... be able to give a clearer picture of soft tissues that do not show up well on x-ray images. Ultrasound causes no health problems and may be repeated as often as is necessary if medically indicated. Ultrasound provides real-time imaging, making it a good tool for guiding ...

  5. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Ultrasound - Pelvis Ultrasound imaging of the pelvis uses sound waves to ...

  6. Interventional ultrasound

    International Nuclear Information System (INIS)

    VanSonnenberg, E.

    1987-01-01

    This book contains 12 chapters and several case studies. Some of the chapter titles are: The Interplay of Ultrasound and Computed Tomography in the Planning and Execution of Interventional Procedures: Ulltrasound Guided Biopsy; Interventioal Genitourinary Sonography; Diagnosis and Treatment of Pericardial Effusion Using Ultrasonic Guidance; and New Ultrasound-Guided Interventional Procedures--Cholecystostomy, Pancreatography, Gastrostomy

  7. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Ultrasound - Pelvis Ultrasound imaging ...

  8. Prostate Ultrasound

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    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Ultrasound - Prostate Ultrasound of ...

  9. Ultrasound stethoscopy

    NARCIS (Netherlands)

    E.C. Vourvouri (Eleni)

    2002-01-01

    textabstractIn this thesis we repmi the many evaluation studies with the hand-held ultrasound device in the assessment of different cardiac pathologies and in different clinical settings. The reason for using the tetm "ultrasound stethoscopy" is that these devices are augmenting our

  10. Ultrasound -- Pelvis

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    Full Text Available ... to-use and less expensive than other imaging methods. Ultrasound imaging is extremely safe and does not use any ionizing radiation. Ultrasound scanning gives a clear picture of soft tissues that do not show up well on ...

  11. Prostate Ultrasound

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    Full Text Available ... the best way to see if treatment is working or if a finding is stable or changed over time. top of page What are the benefits vs. risks? Benefits Ultrasound is widely available, easy-to-use and less expensive than other imaging methods. Ultrasound imaging uses ...

  12. Prostate Ultrasound

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    Full Text Available ... the patient. Because ultrasound images are captured in real-time, they can show the structure and movement of ... blood test result. difficulty urinating. Because ultrasound provides real-time images, it also can be used to guide ...

  13. On the Performance of In-Band Full-Duplex Cooperative Communications

    KAUST Repository

    Khafagy, Mohammad Galal

    2016-01-01

    -duplex potentials. Full-duplex relaying (FDR), where intermediate nodes may now support source-destination communication via simultaneous listening/forwarding, represents one of two full-duplex settings currently recommended for deployment in future fifth

  14. Pre-operative localization of parathyroid adenoma by Tc-99m-sestamibi scintigraphy (MIBI)

    International Nuclear Information System (INIS)

    Ramadan, Edward; Vishne, Tal H; Koren, Romelia; Lerner, Igor; Melloul, Moshe; Dreznik, Zeev

    2002-01-01

    The use of pre-operative imaging for localization of primary parathyroid adenoma may influence the duration and results of parathyroidectomy. The current study was aimed to evaluate the efficiency of localization of parathyroid adenoma by Tc-99m-sestamibi (MIBI) scintigraphy and compare the results with those achieved by the use of preoperative ultrasound. Seventy five patients, aged 25 to 83 years with primary hyperparathyroidism were operated due to primary adenoma in Rabin Medical Center from January 1995 to April 1997. Fifty of them had a preoperative MIBI scintigraphy and ultrasound for localization of parathyroid adenoma, while 25 had a preoperative ultrasound alone. Ultrasound identified correctly the adenoma in 84 percent of the cases, as compared to 96 percent identified by MIBI scintigraphy (p<0.01). MIBI scintigraphy shortened operation length from 120±20 min to 80±15 min (p<0.05) and reduced the number of frozen sections from 2.2±0.4 to 1.1±0.3 (p<0.001). MIBI scintigraphy is the most efficient modality for preoperative localization of parathyroid adenoma as compared to other imaging procedures, and can shorten operative time (Au)

  15. Ultrasound determination of rotator cuff tear repairability

    Science.gov (United States)

    Tse, Andrew K; Lam, Patrick H; Walton, Judie R; Hackett, Lisa

    2015-01-01

    Background Rotator cuff repair aims to reattach the torn tendon to the greater tuberosity footprint with suture anchors. The present study aimed to assess the diagnostic accuracy of ultrasound in predicting rotator cuff tear repairability and to assess which sonographic and pre-operative features are strongest in predicting repairability. Methods The study was a retrospective analysis of measurements made prospectively in a cohort of 373 patients who had ultrasounds of their shoulder and underwent rotator cuff repair. Measurements of rotator cuff tear size and muscle atrophy were made pre-operatively by ultrasound to enable prediction of rotator cuff repairability. Tears were classified following ultrasound as repairable or irreparable, and were correlated with intra-operative repairability. Results Ultrasound assessment of rotator cuff tear repairability has a sensitivity of 86% (p tear size (p tear size ≥4 cm2 or anteroposterior tear length ≥25 mm indicated an irreparable rotator cuff tear. Conclusions Ultrasound assessment is accurate in predicting rotator cuff tear repairability. Tear size or anteroposterior tear length and age were the best predictors of repairability. PMID:27582996

  16. Harvesting full-duplex rate gains in cellular networks with half-duplex user terminals

    KAUST Repository

    AlAmmouri, Ahmad

    2016-07-26

    Full-Duplex (FD) transceivers may be expensive in terms of complexity, power consumption, and price to be implemented in all user terminals. Therefore, techniques to exploit in-band full-duplex communication with FD base stations (BSs) and half-duplex (HD) users\\' equipment (UEs) are required. In this context, 3-node topology (3NT) has been recently proposed for FD BSs to reuse the uplink (UL) and downlink (DL) channels with HD terminals within the same cell. In this paper, we present a tractable mathematical framework, based on stochastic geometry, for 3NT in cellular networks. To this end, we propose a design paradigm via pulse-shaping and partial overlap between UL and DL channels to maximize the harvested rate gains in 3NT. The results show that 3NT achieves a close performance to networks with FD BSs and FD UEs, denoted by 2-node topology (2NT) networks. A maximum of 5% rate loss is reported when 3NT is compared to 2NT with efficient self-interference cancellation (SIC). If the SIC in 2NT is not efficient, 3NT highly outperforms 2NT. Consequently, we conclude that, irrespective to the UE duplexing scheme, it is sufficient to have FD BSs to harvest FD rate gains.

  17. Assessment of extracranial ICA stenosis with color ultrasound and CEMRA

    International Nuclear Information System (INIS)

    Zhao Wenyuan; Liu Jianmin; Xu Yi; Hong Bo; Huang Qinghai; Zhang Long; Zhou Xiaoping

    2003-01-01

    Objective: To evaluate the color ultrasound and CEMRA in assessment of extracranial ICA stenosis. Methods: The preoperation assessment of color ultrasound and CEMRA were reviewed in 93 cases who underwent interventional treatment for severe extracranial ICA stenosis. Results: Ultrasonic examination could reveal the nature and severity of the stenosis, while CEMRA could explore full length of carotid artery and find tandem stenosis. They both possessed a trend for overestimating the stenosis and could hardly show plaque ulceration. Conclusions: Up to the moment, neither color ultrasound nor CEMRA can substitute DSA. A combination of DSA, color ultrasound, and CEMRA could provide details of the stenotic ICA drawing an appropriate operation plan

  18. Structural Properties of G,T-Parallel Duplexes

    Directory of Open Access Journals (Sweden)

    Anna Aviñó

    2010-01-01

    Full Text Available The structure of G,T-parallel-stranded duplexes of DNA carrying similar amounts of adenine and guanine residues is studied by means of molecular dynamics (MD simulations and UV- and CD spectroscopies. In addition the impact of the substitution of adenine by 8-aminoadenine and guanine by 8-aminoguanine is analyzed. The presence of 8-aminoadenine and 8-aminoguanine stabilizes the parallel duplex structure. Binding of these oligonucleotides to their target polypyrimidine sequences to form the corresponding G,T-parallel triplex was not observed. Instead, when unmodified parallel-stranded duplexes were mixed with their polypyrimidine target, an interstrand Watson-Crick duplex was formed. As predicted by theoretical calculations parallel-stranded duplexes carrying 8-aminopurines did not bind to their target. The preference for the parallel-duplex over the Watson-Crick antiparallel duplex is attributed to the strong stabilization of the parallel duplex produced by the 8-aminopurines. Theoretical studies show that the isomorphism of the triads is crucial for the stability of the parallel triplex.

  19. Criteria for the Segmentation of Vowels on Duplex Oscillograms.

    Science.gov (United States)

    Naeser, Margaret A.

    This paper develops criteria for the segmentation of vowels on duplex oscillograms. Previous vowel duration studies have primarily used sound spectrograms. The use of duplex oscillograms, rather than sound spectrograms, permits faster production (real time) at less expense (adding machine paper may be used). The speech signal can be more spread…

  20. Zoster duplex: a clinical report and etiologic analysis.

    Science.gov (United States)

    Zhang, Feng; Zhou, Jin

    2015-01-01

    Herpes zoster (HZ) duplex is a rare disease presentation. The mechanisms of varicella zoster virus (VZV) reactivation in multiple dermal regions are unknown. To present a HZ duplex case occurring in an immunocompetent woman and to analyze the possible underlying causes of HZ duplex. We present a HZ duplex case in an immunocompetent woman and analyzed the possible contributing factors in 36 HZ duplex cases. Continuously distributed variables were categorized by numbers and percentages. In our study, 24 cases (66.7%) were from Asia, 16 cases (44.4%) were in individuals ≥ 50 years of age, and 17 cases (47.2%) occurred in immunocompromised patients. Of the 36 cases, 23 involved women (63.9%) and 13 involved men. Eighteen patients suffering from HZ duplex, 13 of which were women (72.2%), did not suffer from any chronic systemic disease or have a long history of taking drugs. HZ duplex is a rare event that can occur in both immunocompetent and immunosuppressed individuals. HZ duplex might be associated with the Asia region, advanced age, immunosuppression, and being female.

  1. Thermal stability of DNA quadruplex-duplex hybrids.

    Science.gov (United States)

    Lim, Kah Wai; Khong, Zi Jian; Phan, Anh Tuân

    2014-01-14

    DNA has the capacity to adopt several distinct structural forms, such as duplex and quadruplex helices, which have been implicated in cellular processes and shown to exhibit important functional properties. Quadruplex-duplex hybrids, generated from the juxtaposition of these two structural elements, could find applications in therapeutics and nanotechnology. Here we used NMR and CD spectroscopy to investigate the thermal stability of two classes of quadruplex-duplex hybrids comprising fundamentally distinct modes of duplex and quadruplex connectivity: Construct I involves the coaxial orientation of the duplex and quadruplex helices with continual base stacking across the two components; Construct II involves the orthogonal orientation of the duplex and quadruplex helices with no base stacking between the two components. We have found that for both constructs, the stability of the quadruplex generally increases with the length of the stem-loop incorporated, with respect to quadruplexes comprising nonstructured loops of the same length, which showed a continuous drop in stability with increasing loop length. The stability of these complexes, particularly Construct I, can be substantially influenced by the base-pair steps proximal to the quadruplex-duplex junction. Bulges at the junction are largely detrimental to the adoption of the desired G-quadruplex topology for Construct I but not for Construct II. These findings should facilitate future design and prediction of quadruplex-duplex hybrids.

  2. Fetal Ultrasound

    Science.gov (United States)

    ... isn't recommended simply to determine a baby's sex. Similarly, fetal ultrasound isn't recommended solely for the purpose of producing keepsake videos or pictures. If your health care provider doesn' ...

  3. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... and movement of the body's internal organs, as well as blood flowing through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. ...

  4. Prostate Ultrasound

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    Full Text Available ... and movement of the body's internal organs, as well as blood flowing through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. ...

  5. Prostate Ultrasound

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    Full Text Available ... nodule felt by a physician during a routine physical exam or prostate cancer screening exam. an elevated blood test result. difficulty urinating. Because ultrasound provides real-time ...

  6. Prostate Ultrasound

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    Full Text Available ... requested the exam. Usually, the referring physician or health care provider will share the results with you. ... well on x-ray images. Ultrasound causes no health problems and may be repeated as often as ...

  7. Ultrasound -- Pelvis

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    Full Text Available ... ultrasound exams are also used to monitor the health and development of an embryo or fetus during ... requested the exam. Usually, the referring physician or health care provider will share the results with you. ...

  8. Prostate Ultrasound

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    Full Text Available ... probe) and ultrasound gel placed directly on the skin. High-frequency sound waves are transmitted from the ... the transducer (the device placed on the patient's skin to send and receive the returning sound waves), ...

  9. Ultrasound -- Pelvis

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    Full Text Available ... probe) and ultrasound gel placed directly on the skin. High-frequency sound waves are transmitted from the ... the transducer (the device placed on the patient's skin to send and receive the returning sound waves), ...

  10. Prostate Ultrasound

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  11. Ultrasound -- Pelvis

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    Full Text Available ... use different transducers (with different capabilities) during a single exam. The transducer sends out high-frequency sound ... modality for the diagnosis and monitoring of pregnant women and their unborn babies. Ultrasound provides real-time ...

  12. Ultrasound -- Pelvis

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    Full Text Available ... collects the sounds that bounce back and a computer then uses those sound waves to create an ... Ultrasound scanners consist of a console containing a computer and electronics, a video display screen and a ...

  13. Prostate Ultrasound

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  14. Prostate Ultrasound

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  15. Prostate Ultrasound

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    Full Text Available ... is located directly in front of the rectum, so the ultrasound exam is performed transrectally in order ... A follow-up examination may also be necessary so that any change in a known abnormality can ...

  16. Prostate Ultrasound

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    Full Text Available ... the rectal wall is relatively insensitive to the pain in the region of the prostate. A biopsy ... needle biopsies and fluid aspiration. Risks For standard diagnostic ultrasound , there are no known harmful effects on ...

  17. Prostate Ultrasound

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    Full Text Available ... diagnose symptoms such as difficulty urinating or an elevated blood test result. It’s also used to investigate ... physical exam or prostate cancer screening exam. an elevated blood test result. difficulty urinating. Because ultrasound provides ...

  18. Ultrasound -- Pelvis

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    Full Text Available ... The principles are similar to sonar used by boats and submarines. The ultrasound image is immediately visible ... principles involved in the sonar used by bats, ships and fishermen. When a sound wave strikes an ...

  19. Ultrasound -- Pelvis

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    Full Text Available ... areas of the body while other areas, especially air-filled lungs, are poorly suited for ultrasound. For ... make secure contact with the body and eliminate air pockets between the transducer and the skin that ...

  20. Prostate Ultrasound

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    Full Text Available ... a follow-up exam is done because a potential abnormality needs further evaluation with additional views or ... of soft tissues that do not show up well on x-ray images. Ultrasound causes no health ...

  1. Ultrasound -- Pelvis

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    Full Text Available ... a follow-up exam is done because a potential abnormality needs further evaluation with additional views or ... of soft tissues that do not show up well on x-ray images. Ultrasound is the preferred ...

  2. Ultrasound -- Pelvis

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    Full Text Available ... is smaller than the standard speculum used when performing a Pap test . A protective cover is placed ... of soft tissues that do not show up well on x-ray images. Ultrasound is the preferred ...

  3. Prostate Ultrasound

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    Full Text Available ... scanning or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on ... to do the scanning. The transducer is a small hand-held device that resembles a microphone, attached ...

  4. Ultrasound -- Pelvis

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    Full Text Available ... scanning or sonography , involves the use of a small transducer (probe) and ultrasound gel placed directly on ... the child prior to the exam. Bringing books, small toys, music or games can help to distract ...

  5. Prostate Ultrasound

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    Full Text Available ... less than 20 minutes. top of page What will I experience during and after the procedure? Ultrasound ... in the region of the prostate. A biopsy will add time to the procedure. Rarely, a small ...

  6. Ultrasound -- Pelvis

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    Full Text Available ... ultrasound images are reviewed. top of page What will I experience during and after the procedure? For ... in the region of the prostate. A biopsy will add time to the procedure. If a Doppler ...

  7. Ultrasound -- Pelvis

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    Full Text Available ... arteries and veins in the abdomen, arms, legs, neck and/or brain (in infants and children) or ... diagnose symptoms experienced by women such as: pelvic pain abnormal vaginal bleeding other menstrual problems Ultrasound exams ...

  8. Prostate Ultrasound

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    Full Text Available ... gel. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... the best way to see if treatment is working or if a finding is stable or changed ...

  9. Ultrasound -- Pelvis

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    Full Text Available ... and development of an embryo or fetus during pregnancy. See the Obstetrical Ultrasound page for more information . ... move through vessels. The movement of blood cells causes a change in pitch of the reflected sound ...

  10. Ultrasound -- Pelvis

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    Full Text Available ... abdomen, arms, legs, neck and/or brain (in infants and children) or within various body organs such ... and monitoring of pregnant women and their unborn babies. Ultrasound provides real-time imaging, making it a ...

  11. Ultrasound -- Pelvis

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    Full Text Available ... to-use and less expensive than other imaging methods. Ultrasound imaging is extremely safe and does not ... barium exams, CT scanning , and MRI are the methods of choice in such a setting. Large patients ...

  12. Ultrasound -- Pelvis

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    Full Text Available ... insertion. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... move through vessels. The movement of blood cells causes a change in pitch of the reflected sound ...

  13. Prostate Ultrasound

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    Full Text Available ... gel. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... requested the exam. Usually, the referring physician or health care provider will share the results with you. ...

  14. Ultrasound -- Pelvis

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    Full Text Available ... insertion. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... requested the exam. Usually, the referring physician or health care provider will share the results with you. ...

  15. Ultrasound imaging

    International Nuclear Information System (INIS)

    Wells, P.N.T.

    1983-01-01

    Ultrasound is a form of energy which consists of mechanical vibrations the frequencies of which are so high that they are above the range of human hearing. The lower frequency limit of the ultrasonic spectrum may generally be taken to be about 20 kHz. Most biomedical applications of ultrasound employ frequencies in the range 1-15 MHz. At these frequencies, the wavelength is in the range 1.5 - 0.1 mm in soft tissues, and narrow beams of ultrasound can be generated which propagate through such tissues without excessive attenuation. This chapter begins with brief reviews of the physics of diagnostic ultrasound pulse-echo imaging methods and Doppler imaging methods. The remainder of the chapter is a resume of the applications of ultrasonic imaging to physiological measurement

  16. Ultrasound -- Pelvis

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    Full Text Available ... be necessary. Your doctor will explain the exact reason why another exam is requested. Sometimes a follow- ... Ultrasound provides real-time imaging, making it a good tool for guiding minimally invasive procedures such as ...

  17. Prostate Ultrasound

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    Full Text Available ... be necessary. Your doctor will explain the exact reason why another exam is requested. Sometimes a follow- ... Ultrasound provides real-time imaging, making it a good tool for guiding minimally invasive procedures such as ...

  18. Ultrasound -- Pelvis

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    Full Text Available ... frequently used to evaluate the reproductive and urinary systems. Ultrasound is safe, noninvasive and does not use ... and evaluate a variety of urinary and reproductive system disorders in both sexes without x-ray exposure. ...

  19. Ultrasound -- Pelvis

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    Full Text Available ... be asked to drink water prior to the examination to fill your bladder. Leave jewelry at home ... those sound waves to create an image. Ultrasound examinations do not use ionizing radiation (as used in ...

  20. Prostate Ultrasound

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    Full Text Available ... top of page Additional Information and Resources RTAnswers.org Radiation Therapy for Prostate Cancer top of page ... to Ultrasound - Prostate Sponsored by Please note RadiologyInfo.org is not a medical facility. Please contact your ...

  1. Prostate Ultrasound

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    Full Text Available ... with measurements acquired as needed for any treatment planning. detect an abnormal growth within the prostate. help ... end of their bowel (rectum) removed during prior surgery are not good candidates for ultrasound of the ...

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    Full Text Available ... tip of the transducer is smaller than the standard speculum used when performing a Pap test . A ... both sexes without x-ray exposure. Risks For standard diagnostic ultrasound , there are no known harmful effects ...

  3. Prostate Ultrasound

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    Full Text Available ... prostate gland and to help diagnose symptoms such as difficulty urinating or an elevated blood test result. ... image. Ultrasound examinations do not use ionizing radiation (as used in x-rays ), thus there is no ...

  4. Ultrasound -- Pelvis

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    Full Text Available ... in the abdomen, arms, legs, neck and/or brain (in infants and children) or within various body organs ... or uterine cancers A transvaginal ultrasound is usually performed to view ...

  5. Prostate Ultrasound

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    Full Text Available ... is enlarged, also known as benign prostatic hyperplasia (BPH) , with measurements acquired as needed for any treatment ... caption Related Articles and Media Benign Prostatic Hyperplasia (BPH) (Enlargement of the Prostate) Prostate Cancer Ultrasound- and ...

  6. Ultrasound -- Pelvis

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    Full Text Available ... the exam. Bringing books, small toys, music or games can help to distract the child and make ... modality for the diagnosis and monitoring of pregnant women and their unborn babies. Ultrasound provides real-time ...

  7. Ultrasound -- Pelvis

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    Full Text Available ... uterine cavity . Three-dimensional (3-D) ultrasound permits evaluation of the uterus and ovaries in planes that ... a special study usually done to provide detailed evaluation of the prostate gland, involves inserting a specialized ...

  8. Ultrasound -- Pelvis

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    Full Text Available ... the examination process. To ensure a smooth experience, it often helps to explain the procedure to the ... on the amplitude (loudness), frequency (pitch) and time it takes for the ultrasound signal to return from ...

  9. Prostate Ultrasound

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    Full Text Available ... difficulty urinating or an elevated blood test result. It’s also used to investigate a nodule found during ... difficulty urinating. Because ultrasound provides real-time images, it also can be used to guide procedures such ...

  10. Prostate Ultrasound

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    Full Text Available ... needle biopsies and fluid aspiration. Risks For standard diagnostic ultrasound , there are no known harmful effects on ... and Resources RTAnswers.org Radiation Therapy for Prostate Cancer top of page This page was reviewed on ...

  11. Ultrasound -- Pelvis

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    Full Text Available ... sexes without x-ray exposure. Risks For standard diagnostic ultrasound , there are no known harmful effects on ... and Resources RTAnswers.org Radiation Therapy for Gynecologic Cancers Radiation Therapy for Prostate Cancer top of page ...

  12. Prostate Ultrasound

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    Full Text Available ... rectum. top of page What are some common uses of the procedure? A transrectal ultrasound of the ... is done because a potential abnormality needs further evaluation with additional views or a special imaging technique. ...

  13. Ultrasound -- Pelvis

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    Full Text Available ... legs, neck and/or brain (in infants and children) or within various body organs such as the ... tumors other disorders of the urinary bladder In children, pelvic ultrasound can help evaluate: pelvic masses pelvic ...

  14. Ultrasound -- Pelvis

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    Full Text Available ... uterus). Sonohysterography allows for a more in-depth investigation of the uterine cavity . Three-dimensional (3-D) ... to-use and less expensive than other imaging methods. Ultrasound imaging is extremely safe and does not ...

  15. Ultrasound -- Pelvis

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    Full Text Available ... is Pelvic Ultrasound Imaging? What are some common uses of the procedure? How should I prepare? What does the equipment look like? How does the procedure work? How is the procedure performed? What will I ...

  16. Ultrasound -- Pelvis

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    Full Text Available ... quickly. The ultrasound exam room may have a television. Feel free to ask for your child's favorite ... display screen that looks like a computer or television monitor. The image is created based on the ...

  17. Prostate Ultrasound

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    Full Text Available ... Images related to Ultrasound - Prostate Sponsored by Please note RadiologyInfo.org is not a medical facility. Please ... is further reviewed by committees from the American College of Radiology (ACR) and the Radiological Society of ...

  18. Ultrasound -- Pelvis

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    Full Text Available ... Images related to Ultrasound - Pelvis Sponsored by Please note RadiologyInfo.org is not a medical facility. Please ... is further reviewed by committees from the American College of Radiology (ACR) and the Radiological Society of ...

  19. Ultrasound -- Pelvis

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    Full Text Available ... symptoms experienced by women such as: pelvic pain abnormal vaginal bleeding other menstrual problems Ultrasound exams also ... endometrial polyps fibroids cancer, especially in patients with abnormal uterine bleeding Some physicians also use 3-D ...

  20. Ultrasound -- Pelvis

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    Full Text Available ... The ultrasound exam room may have a television. Feel free to ask for your child's favorite channel. ... performed over an area of tenderness, you may feel pressure or minor pain from the transducer. Once ...

  1. Prostate Ultrasound

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    Full Text Available ... also known as benign prostatic hyperplasia (BPH) , with measurements acquired as needed for any treatment planning. detect ... areas of the body while other areas, especially air-filled lungs, are poorly suited for ultrasound. For ...

  2. Ultrasound -- Pelvis

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    Full Text Available ... ovarian cysts and uterine fibroids ovarian or uterine cancers A transvaginal ultrasound is usually performed to view ... detect: uterine anomalies uterine scars endometrial polyps fibroids cancer, especially in patients with abnormal uterine bleeding Some ...

  3. Prostate Ultrasound

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    Full Text Available ... rectum. top of page What are some common uses of the procedure? A transrectal ultrasound of the ... community, you can search the ACR-accredited facilities database . This website does not provide cost information. The ...

  4. Ultrasound -- Pelvis

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    Full Text Available ... kidneys. top of page What are some common uses of the procedure? In women, a pelvic ultrasound ... community, you can search the ACR-accredited facilities database . This website does not provide cost information. The ...

  5. Ultrasound -- Pelvis

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    Full Text Available ... of the reflected sound waves (called the Doppler effect). A computer collects and processes the sounds and ... standard diagnostic ultrasound , there are no known harmful effects on humans. top of page What are the ...

  6. Ultrasound -- Pelvis

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    Full Text Available ... sends out high-frequency sound waves (that the human ear cannot hear) into the body and then ... ultrasound , there are no known harmful effects on humans. top of page What are the limitations of ...

  7. Ultrasound -- Pelvis

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    Full Text Available ... various body organs such as the liver or kidneys. top of page What are some common uses ... women, a pelvic ultrasound exam can help identify: kidney stones bladder tumors other disorders of the urinary ...

  8. Ultrasound -- Pelvis

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    Full Text Available ... the ovaries. Transvaginal ultrasound also evaluates the myometrium (muscular walls of the uterus). Sonohysterography allows for a ... and evaluate a variety of urinary and reproductive system disorders in both sexes without x-ray exposure. ...

  9. Prostate Ultrasound

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    Full Text Available ... echoes from the tissues in the body. The principles are similar to sonar used by boats and ... work? Ultrasound imaging is based on the same principles involved in the sonar used by bats, ships ...

  10. Ultrasound -- Pelvis

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    Full Text Available ... echoes from the tissues in the body. The principles are similar to sonar used by boats and ... work? Ultrasound imaging is based on the same principles involved in the sonar used by bats, ships ...

  11. Prostate Ultrasound

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    Full Text Available ... is at high risk for cancer. In this case, a biopsy is performed and an ultrasound probe ... will share the results with you. In some cases, the radiologist may discuss results with you at ...

  12. Ultrasound -- Pelvis

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    Full Text Available ... ovaries. Transvaginal ultrasound also evaluates the myometrium (muscular walls of the uterus). Sonohysterography allows for a more ... needle insertion) is usually minimal because the rectal wall is relatively insensitive to the pain in the ...

  13. Prostate Ultrasound

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    Full Text Available ... uses sound waves to produce pictures of a man’s prostate gland and to help diagnose symptoms such ... also called transrectal ultrasound, provides images of a man's prostate gland and surrounding tissue. The exam typically ...

  14. Ultrasound -- Pelvis

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    Full Text Available ... pain ambiguous genitalia and anomalies of pelvic organs early or delayed puberty in girls Pelvic ultrasound is ... sensitive to motion, and an active or crying child can prolong the examination process. To ensure a ...

  15. Ultrasound -- Pelvis

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    Full Text Available ... consist of a console containing a computer and electronics, a video display screen and a transducer that ... the preferred imaging modality for the diagnosis and monitoring of pregnant women and their unborn babies. Ultrasound ...

  16. Ultrasound -- Pelvis

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    Full Text Available ... insertion. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... the transducer is pressed against the skin, it directs small pulses of inaudible, high-frequency sound waves ...

  17. Prostate Ultrasound

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    Full Text Available ... gel. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... the transducer is pressed against the skin, it directs small pulses of inaudible, high-frequency sound waves ...

  18. Duplex tube steam reformer development program

    International Nuclear Information System (INIS)

    Lewe, C.K.; Nieto, J.M.; Papadopoulos, A.

    1978-09-01

    Work done in partial fulfillment of Task 7 of the Duplex Steam Reformer Development Program is described. The DSR concept acts as a double barrier between a process heat high temperature reactor plant (PNP) and a closed loop chemical heat pipe (CHP) for the long distance transport of chemical energy to a remote industrial user. The current state of the DSR design is described as well as related systems and equipment. The PNP concept presented is based upon work currently underway in the Federal Republic of Germany

  19. Full Duplex Communications in 5G Small Cells

    DEFF Research Database (Denmark)

    Mahmood, Nurul Huda; Gatnau, Marta; Berardinelli, Gilberto

    2017-01-01

    Full duplex communication promises system performance improvement over conventional half duplex communication by allowing simultaneous transmission and reception. However, such concurrent communication results in strong self interference and an increase in the overall network interference, and can...... only be exploited when traffic is available in both directions. The potential throughput gains of full duplex communication over conventional half duplex transmission in a small cell network with asymmetric traffic conditions is investigated in this contribution. The throughput performance gains...... are analysed using tools from stochastic geometry, and further confirmed through extensive system level simulations. Our findings explicitly quantify how the gains from full duplex communication depend on the traffic profile and the inter-cell interference coupling. The demonstrated throughput gains and delay...

  20. Adopting preoperative fasting guidelines.

    Science.gov (United States)

    Anderson, Megan; Comrie, Rhonda

    2009-07-01

    In 1999, the American Society of Anesthesiologists adopted preoperative fasting guidelines to enhance the quality and efficiency of patient care. Guidelines suggest that healthy, non-pregnant patients should fast six hours from solids and two hours from liquids. Although these guidelines are in place, studies suggest that providers are still using the blanket statement "NPO after midnight" without regard to patient characteristics, the procedure, or the time of the procedure. Using theory to help change provider's beliefs may help make change more successful. Rogers' Theory of Diffusion of Innovations can assist in changing long-time practice by laying the groundwork for an analysis of the benefits and disadvantages of proposed changes, such as changes to fasting orders, while helping initiate local protocols instead of additional national guidelines.

  1. Carotid Consensus Panel duplex criteria can replace modified University of Washington criteria without affecting accuracy.

    Science.gov (United States)

    Kim, Ann H; Augustin, Gener; Shevitz, Andrew; Kim, Hannah; Trivonovich, Michael R; Powell, Alexis R; Kumins, Norman; Tarr, Robert; Kashyap, Vikram S

    2018-04-01

    The decision to intervene for internal carotid stenosis often depends on the degree of stenosis seen on duplex ultrasound (US). The aim of this study is to compare the diagnostic accuracy of two criteria: modified University of Washington (UW) and 2003 Carotid Consensus Panel (CCP). All patients undergoing US in an accredited (IAC) vascular laboratory from January 2010 to June 2015 were reviewed ( n=18,772 US exams). Patients receiving a neck computed tomography angiography (CTA) within 6 months of the US were included in the study ( n=254). The degree of stenosis was determined by UW/CCP criteria and confirmed on CTA images using North American Symptomatic Carotid Endarterectomy Trial (NASCET)/European Carotid Surgery Trial (ECST) schema. Kappa analysis with 95% confidence intervals (CIs) were utilized to determine duplex-CTA agreement. A total of 417 carotid arteries from 221 patients were assessed in this study. The modified UW criteria accurately classified 266 (63.9%, kappa = 0.321, 95% CI 0.255 to 0.386) cases according to NASCET-derived measurements. The sensitivity, specificity, and accuracy at ≥ 60% stenosis were 65.7%, 81.3%, and 81.9%. The CCP criteria resulted in 296 (70.9%) accurate diagnoses (kappa = 0.359, 95% CI 0.280 to 0.437). At ≥ 70% stenosis, the sensitivity, specificity and accuracy were 38.8%, 91.6%, and 87.1% for NASCET. Comparison of the duplex results to ECST-derived CTA measurements revealed a similar trend (UW 53.1%, κ = 0.301 vs CCP 62.1%, κ = 0.315). The CCP criteria demonstrate a higher concordance rate with measurements taken from CTAs. The CCP criteria may be more sensitive in classifying clinically significant degrees of stenosis without a loss in diagnostic accuracy.

  2. Dextranomer/hyaluronic acid endoscopic injection is effective in the treatment of intermediate and high grade vesicoureteral reflux in patients with complete duplex systems.

    Science.gov (United States)

    Hunziker, Manuela; Mohanan, Nochiparambil; Puri, Prem

    2013-05-01

    Endoscopic subureteral injection of dextranomer/hyaluronic acid has become an established alternative to long-term antibiotic prophylaxis or surgical treatment for vesicoureteral reflux. We evaluated the effectiveness of endoscopic injection of dextranomer/hyaluronic acid in intermediate and high grade vesicoureteral reflux in patients with complete duplex collecting systems. A total of 123 children underwent endoscopic correction of intermediate or high grade vesicoureteral reflux using injection of dextranomer/hyaluronic acid into complete duplex systems between 2001 and 2010. Vesicoureteral reflux was diagnosed by voiding cystourethrogram, and dimercapto-succinic acid scan was performed to evaluate the presence of renal scarring. Followup ultrasound and voiding cystourethrogram were performed 3 months after the outpatient procedure and renal ultrasound thereafter every 2 years. Mean followup was 6.7 years. Complete duplex systems were unilateral in 110 patients and bilateral in 13. Reflux severity in the 136 refluxing units was grade II in 1 (0.7%), III in 52 (38.2%), IV in 61 (44.9%) and V in 22 (16.2%). Dimercapto-succinic acid scan revealed renal functional abnormalities in 63 children (51.2%). Vesicoureteral reflux resolved after the first endoscopic injection of dextranomer/hyaluronic acid in 93 ureters (68.4%), after a second injection in 35 (25.7%) and after a third injection in 8 (5.9%). Febrile urinary tract infection developed in 5 patients (4.1%) during followup. No patient required ureteral reimplantation or experienced significant complications. Our results confirm the safety and efficacy of endoscopic injection of dextranomer/hyaluronic acid in eradicating intermediate and high grade vesicoureteral reflux in patients with complete duplex systems. We recommend this minimally invasive, 15-minute outpatient procedure as a viable option for treating intermediate and high grade vesicoureteral reflux in patients with complete duplex collecting systems

  3. Cranial Ultrasound/Head Ultrasound

    Science.gov (United States)

    ... used to screen for brain conditions associated with prematurity, such as bleeding or brain tissue damage as ... or crying child will slow the examination process. Large patients are more difficult to image by ultrasound, ...

  4. General Ultrasound Imaging

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    Full Text Available ... guide biopsy of breast cancer ( see the Ultrasound-Guided Breast Biopsy page . diagnose a variety of heart ... Articles and Media Angioplasty and Vascular Stenting Ultrasound-Guided Breast Biopsy Obstetric Ultrasound Ultrasound - Prostate Biopsies - Overview ...

  5. General Ultrasound Imaging

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    Full Text Available ... of an ultrasound examination. Doppler ultrasound , also called color Doppler ultrasonography, is a special ultrasound technique that ... kidneys. There are three types of Doppler ultrasound: Color Doppler uses a computer to convert Doppler measurements ...

  6. General Ultrasound Imaging

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    Full Text Available ... Index A-Z General Ultrasound Ultrasound imaging uses sound waves to produce pictures of the inside of ... pictures of the inside of the body using sound waves. Ultrasound imaging, also called ultrasound scanning or ...

  7. General Ultrasound Imaging

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    Full Text Available ... those sound waves to create an image. Ultrasound examinations do not use ionizing radiation (as used in ... ultrasound study may be part of an ultrasound examination. Doppler ultrasound , also called color Doppler ultrasonography, is ...

  8. General Ultrasound Imaging

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    Full Text Available ... What are the limitations of General Ultrasound Imaging? What is General Ultrasound Imaging? Ultrasound is safe and ... be heard with every heartbeat. top of page What are some common uses of the procedure? Ultrasound ...

  9. Importance of Preoperative Rectal Ultrasound and CT in Rectal Tumors

    International Nuclear Information System (INIS)

    Schnellyova, T.

    2011-01-01

    Introduction: The reason of high mortality of colorectal carcinoma is above all the fact, that majority of diseases are detected in progressive stage. Radical change in this unfavorable mortality rate can be achieved only by targeted search for early stages of the disease. Early diagnostics consists in rectoscopy and colonoscopy. Regarding X-ray methods it is X-ray irigography. Regarding CT examinations it is CT irigography, virtual colonoscopy. Another examination can be USG examination of abdomen and endo sonographic examination of rectum. Materials and methods: In the period from June 2006 to December 2010, in 60 patients out of the total number 106 examined patients, tumorous affection of rectum CT examination of pelvis and abdomen separately or pelvisand abdomen at one session was made in 3186 patients. In 115 patients we discovered malign tumorous illness of colon. Metastatic affection in the form of distant metastases was proven n 63 patients. 403 patients had CT irigography examination. In 77 out of them we diagnosed colon carcinoma. CT colonoscopy did not discover in our group of 30 patients examined the presence of colon carcinoma. Results: In the group of 60 patients who were diagnosed rectal carcinoma, in 29 patients expansive infiltrative affection was evaluated in endorectal sonography, histologically confirmed in 28 patients - 96,5 %, expansive affection in 41 patients with histological verification in 100 %. With CT we diagnosed 52 expansive tumorous processes, histologically confirmed in 47 patients - 90,38 %. In 63 patients expansive infiltrative process was evaluated, histologically confirmed in 52 patients 82,53 %. In total of 115 examinations there was conformance with histological examination in 99 patients - 86,08 %. In CT irigography we diagnosed colon tumour in 77 patients. Expansive growth was evaluated in 40 patients, histologically confirmed in 37 patients - 92,5 %. Expansive infiltrative expansion was evaluated in 37 patients, with histological verification in 9 patients - 78,3 %. In total we marked conformance of CT irigography with histological examination in 85,71 examinations. In CT virtual colonoscopy we did not diagnose any case of malign colon affection. Conclusion: Early diagnostics of primary colorectal carcinoma is the only possibility how to improve the prognosis of the patients. Endorectal sonography should serve as a complement to other examination methods. It assesses the principal expansion of the tumour in the rectal wall, infiltration in the surroundings. MSCT of abdomen and pelvis brings excellent results and the surgeon can evaluate in selecting the appropriate type of operation. The benefits of this methodology is high in assessing the local finding as well as in assessing the presence of metastases in parenchyma organs or lymphatic nods. CT irigography better evaluated intestinal wall, its thickness, bordering or infiltration to the surroundings. A part of the examination is also evaluation of the state of the organs of abdominal cavity, pelvis, LU. Virtual colonoscopy is an excellent screening method to search for polyps of colorectum, which are considered pre-cancerosis. (author)

  10. Corrosion behavior of 2205 duplex stainless steel.

    Science.gov (United States)

    Platt, J A; Guzman, A; Zuccari, A; Thornburg, D W; Rhodes, B F; Oshida, Y; Moore, B K

    1997-07-01

    The corrosion of 2205 duplex stainless steel was compared with that of AISI type 316L stainless steel. The 2205 stainless steel is a potential orthodontic bracket material with low nickel content (4 to 6 wt%), whereas the 316L stainless steel (nickel content: 10 to 14 wt%) is a currently used bracket material. Both stainless steels were subjected to electrochemical and immersion (crevice) corrosion tests in 37 degrees C, 0.9 wt% sodium chloride solution. Electrochemical testing indicates that 2205 has a longer passivation range than 316L. The corrosion rate of 2205 was 0.416 MPY (milli-inch per year), whereas 316L exhibited 0.647 MPY. When 2205 was coupled to 316L with equal surface area ratio, the corrosion rate of 2205 reduced to 0.260 MPY, indicating that 316L stainless steel behaved like a sacrificial anode. When 316L is coupled with NiTi, TMA, or stainless steel arch wire and was subjected to the immersion corrosion test, it was found that 316L suffered from crevice corrosion. On the other hand, 2205 stainless steel did not show any localized crevice corrosion, although the surface of 2205 was covered with corrosion products, formed when coupled to NiTi and stainless steel wires. This study indicates that considering corrosion resistance, 2205 duplex stainless steel is an improved alternative to 316L for orthodontic bracket fabrication when used in conjunction with titanium, its alloys, or stainless steel arch wires.

  11. Electrolytic pickling of duplex stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Ipek, N.; Holm, B.; Pettersson, R. [Swedish Institute for Metals Research, Drottning Kristinas vaeg 48, 11428 Stockholm (Sweden); Runnsjoe, G.; Karlsson, M. [Outokumpu Stainless AB, 77422 Avesta (Sweden)

    2005-08-01

    Pickling of duplex stainless steels has proved to be much more difficult than that of standard austenitic grades. Electrolytic pre-pickling is shown to be a key process towards facilitating the pickling process for material annealed both in the production-line and in laboratory experiments. The mechanism for the neutral electrolytic process on duplex 2205 and austenitic 316 steels has been examined and the oxide scale found to become thinner as a function of electrolytic pickling time. Spallation or peeling of the oxide induced by gas evolution did not play a decisive role. A maximum of about 20% of the current supplied to the oxidised steel surface goes to dissolution reactions whereas about 80% of the current was consumed in oxygen gas production. This makes the current utilisation very poor, particularly against the background of reports that in indirect electrolytic pickling only about 30% of the total current, supplied to the process, actually goes into the strip. A parametric study was therefore carried out to determine whether adjustment of process variables could improve the current utilisation. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

  12. On phase equilibria in duplex stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Wessman, S. [Swerea KIMAB AB, Stockholm (Sweden); Pettersson, R. [Outokumpu Stainless AB, Avesta Research Centre, Avesta (Sweden); Hertzman, S. [Outokumpu Stainless Research Foundation, Stockholm (Sweden)

    2010-05-15

    The equilibrium conditions of four duplex stainless steels; Fe-23Cr-4.5Ni-0.1N, Fe-22Cr-5.5Ni-3Mo-0.17N, Fe-25Cr-7Ni-4Mo-0.27N and Fe-25Cr-7Ni-4Mo-1W-1.5Cu-0.27N were studied in the temperature region from 700 to 1000 C. Phase compositions were determined with SEM EDS and the phase fractions using image analysis on backscattered SEM images. The results showed that below 1000 C the steels develop an inverse duplex structure with austenite and sigma phase, of which the former is the matrix phase. With decreasing temperature, the microstructure will be more and more complex and finely dispersed. The ferrite is, for the higher alloyed steels, only stable above 1000 C and at lower temperatures disappears in favour of intermetallic phases. The major intermetallic phase is sigma phase with small amounts of chi phase, the latter primarily in high Mo and W grades. Nitrides, not a focus in this investigation, were present as rounded particles and acicular precipitates at lower temperatures. The results were compared to theoretical predictions using the TCFE5 and TCFE6 databases. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  13. [Ultrasound diagnosis of aneurysm of the vein of Galen in children].

    Science.gov (United States)

    Gazikalović, S; Kosutić, J; Komar, P; Vukomanović, V; Mogić, M

    2001-01-01

    Aneurysm of the vein of Galen is rare and complex vascular disorder that develops during embriogenesis and provokes significant haemodynamic changes. Boys are more frequently involved. During the foetal period Ballantyne syndrome may develop, and postnatal clinical presentation vary with ages. Serious haemodynamic changes are followed by congestive heart failure and, if not treated, with lethal exitus. Fast and correct diagnosis is very important. Ultrasound examination of central nervous system supported with Duplex-Doppler and Colour-Doppler examination of the head and heart enables the diagnosis. This text comments ultrasound presentation of the malformation and ultrasound diagnostic possibilities.

  14. Rietveld and impedance analysis of cold and hot rolled duplex and lean duplex steels for application in paper and pulp industry

    Energy Technology Data Exchange (ETDEWEB)

    Esteves, Luiza; Lins, Vanessa de Freitas Cunha, E-mail: luizaeq@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Quimica; Paiva, Paulo Renato Perdigao [Centro Federal de Educacao Tecnologica de Minas Gerais (CEFET), Belo Horizonte, MG (Brazil); Viana, Adolfo Kalergis do Nascimento [APERAM South America, Timoteo, MG (Brazil)

    2017-01-15

    In this study, X-Ray Diffraction (XRD) and Rietveld Refinement were performed to identify and quantify the ferrite and austenite phase of cold and hot rolled duplex stainless steels (UNS S31803) and lean duplex stainless steels (UNS S32304). Electrochemical impedance spectroscopy (EIS) was applied to evaluate the chemical behavior of duplex and lean duplex stainless steels in white, green, and black liquors of paper and pulp industry. Rietveld analysis results showed a higher austenite content than the standard limit for duplex steels in the hot rolled condition. The hot rolling condition plays a major role in improving corrosion resistance in white liquor mainly for the lean duplex steel. (author)

  15. Rietveld and impedance analysis of cold and hot rolled duplex and lean duplex steels for application in paper and pulp industry

    International Nuclear Information System (INIS)

    Esteves, Luiza; Lins, Vanessa de Freitas Cunha; Viana, Adolfo Kalergis do Nascimento

    2017-01-01

    In this study, X-Ray Diffraction (XRD) and Rietveld Refinement were performed to identify and quantify the ferrite and austenite phase of cold and hot rolled duplex stainless steels (UNS S31803) and lean duplex stainless steels (UNS S32304). Electrochemical impedance spectroscopy (EIS) was applied to evaluate the chemical behavior of duplex and lean duplex stainless steels in white, green, and black liquors of paper and pulp industry. Rietveld analysis results showed a higher austenite content than the standard limit for duplex steels in the hot rolled condition. The hot rolling condition plays a major role in improving corrosion resistance in white liquor mainly for the lean duplex steel. (author)

  16. Transvaginal ultrasound assessment of myometrial and cervical stroma invasion in women with endometrial cancer -interobserver reproducibility among ultrasound experts and gynaecologists

    DEFF Research Database (Denmark)

    Eriksson, LS; Lindqvist, PG; Flöter Rådestad, A

    2014-01-01

    OBJECTIVES: To assess interobserver reproducibility among ultrasound experts and gynaecologists in the prediction of deep myometrial- and cervical stroma invasion by transvaginal ultrasound in women with endometrial cancer. METHODS: Video-clips of the corpus- and cervix uteri of 53 women...... with endometrial cancer, examined preoperatively by the same ultrasound expert, were integrated in a digitalized survey. Nine ultrasound experts and 9 gynaecologists evaluated presence or absence of deep myometrial- and cervical stroma invasion. Histopathology from hysterectomy specimen was used as gold standard.......001). CONCLUSION: Preoperative ultrasound assessment of deep myometrial- and cervical stroma invasion in endometrial cancer is best performed by ultrasound experts, as they show a higher degree of agreement to histopathology and higher interobserver reproducibility in the assessment of cervical stromal invasion....

  17. Therapeutic ultrasound

    International Nuclear Information System (INIS)

    Crum, Lawrence A

    2004-01-01

    The use of ultrasound in medicine is now quite commonplace, especially with the recent introduction of small, portable and relatively inexpensive, hand-held diagnostic imaging devices. Moreover, ultrasound has expanded beyond the imaging realm, with methods and applications extending to novel therapeutic and surgical uses. These applications broadly include: tissue ablation, acoustocautery, lipoplasty, site-specific and ultrasound mediated drug activity, extracorporeal lithotripsy, and the enhancement of natural physiological functions such as wound healing and tissue regeneration. A particularly attractive aspect of this technology is that diagnostic and therapeutic systems can be combined to produce totally non-invasive, imageguided therapy. This general lecture will review a number of these exciting new applications of ultrasound and address some of the basic scientific questions and future challenges in developing these methods and technologies for general use in our society. We shall particularly emphasize the use of High Intensity Focused Ultrasound (HIFU) in the treatment of benign and malignant tumors as well as the introduction of acoustic hemostasis, especially in organs which are difficult to treat using conventional medical and surgical techniques. (amum lecture)

  18. Buffer management in wireless full-duplex systems

    KAUST Repository

    Bouacida, Nader

    2015-10-19

    Wireless full-duplex radios can simultaneously transmit and receive using the same frequency. In theory, this can double the throughput. In fact, there is only little work addressing aspects other than throughput gains in full-duplex systems. Over-buffering in today\\'s networks or the so-called “bufferbloat” phenomenon creates excessive end-to-end delays resulting in network performance degradation. Our analysis shows that full-duplex systems may suffer from high latency caused by bloated buffers. In this paper, we address the problem of buffer management in full-duplex networks by using Wireless Queue Management (WQM), which is an active queue management technique for wireless networks. Our solution is based on Relay Full-Duplex MAC (RFD-MAC), an asynchronous media access control protocol designed for relay full-duplexing. We compare the performance of WQM in full-duplex environment to Drop Tail mechanism over various scenarios. Our solution reduces the end-to-end delay by two orders of magnitude while achieving similar throughput in most of the cases.

  19. Target motion predictions for pre-operative planning during needle-based interventions

    NARCIS (Netherlands)

    op den Buijs, J.; Abayazid, Momen; de Korte, Chris L.; Misra, Sarthak

    During biopsies, breast tissue is subjected to displacement upon needle indentation, puncture, and penetration. Thus, accurate needle placement requires pre-operative predictions of the target motions. In this paper, we used ultrasound elastography measurements to non-invasively predict elastic

  20. Capturing a DNA duplex under near-physiological conditions

    Science.gov (United States)

    Zhang, Huijuan; Xu, Wei; Liu, Xiaogang; Stellacci, Francesco; Thong, John T. L.

    2010-10-01

    We report in situ trapping of a thiolated DNA duplex with eight base pairs into a polymer-protected gold nanogap device under near-physiological conditions. The double-stranded DNA was captured by electrophoresis and covalently attached to the nanogap electrodes through sulfur-gold bonding interaction. The immobilization of the DNA duplex was confirmed by direct electrical measurements under near-physiological conditions. The conductance of the DNA duplex was estimated to be 0.09 μS. We also demonstrate the control of DNA dehybridization by heating the device to temperatures above the melting point of the DNA.

  1. Value of venous color flow duplex scan as initial screening test for geriatric inpatients with clinically suspected pulmonary embolism

    Directory of Open Access Journals (Sweden)

    Kreidy R

    2011-09-01

    Full Text Available Raghid Kreidy1, Elias Stephan2, Pascale Salameh3, Mirna Waked4 1Department of Vascular Surgery, Saint George Hospital, University Medical Center, University of Balamand, Beirut, Lebanon; 2Department of Geriatrics, Saint George Hospital, University Medical Center, University of Balamand, Beirut, Lebanon; 3Laboratory of Clinical and Epidemiological Research, Faculty of Pharmacy, Lebanese University, 4Department of Pulmonary Medicine, Saint George Hospital, University Medical Center, University of Balamand, Beirut, Lebanon Aim: The contribution of lower extremity venous duplex scan to the diagnostic strategy for pulmonary embolism has been demonstrated by many authors. However, the positive diagnostic value of this noninvasive test in clinically suspected pulmonary embolism is not very high (10%–18%. Since thromboembolic risks increase considerably in hospitalized patients with advanced age, this study aims to determine the importance of lower extremity venous color flow duplex scan in this particular subgroup of patients with clinically suspected pulmonary embolism. The effects of clinical presentation and risk factors on the results of duplex scan have been also studied. Methods: Between July 2007 and January 2010, 95 consecutive Lebanese geriatric ($60 years of age inpatients with clinically suspected pulmonary embolism assessed in an academic tertiary-care center for complete lower extremity venous color flow duplex scan were retrospectively reviewed. Age varied between 60 and 96 years (mean, 79.9 years. Forty patients were males and 55 females. Absence of compressibility was the most important criteria for detecting acute venous thrombosis. Results: Out of 95 patients, 33 patients (34.7% were diagnosed with recent deep venous thrombosis of lower extremities (14 proximal and 19 distal using complete venous ultrasound. Nine of these 33 patients (27.2% had a history of venous thromboembolism and eleven (33.3% presented with edema of lower

  2. Apparent diffusion coefficient of renal parenchyma and color Doppler ultrasound of intrarenal arteries in patients with cirrhosis related renal dysfunction

    Directory of Open Access Journals (Sweden)

    Mohamed M Hefeda

    2014-12-01

    Conclusion: Liver cirrhosis, even in the presence of refractory ascites, did not affect the ADC value of renal parenchyma, however ADC value is affected in renal parenchyma of patients with hepato-renal syndrome. Duplex-Doppler ultrasound of intrarenal arteries enables the early detection of renal hemodynamic disturbances in patients with liver cirrhosis.

  3. Corrosion behavior of sensitized duplex stainless steel.

    Science.gov (United States)

    Torres, F J; Panyayong, W; Rogers, W; Velasquez-Plata, D; Oshida, Y; Moore, B K

    1998-01-01

    The present work investigates the corrosion behavior of 2205 duplex stainless steel in 0.9% NaCl solution after various heat-treatments, and compares it to that of 316L austenitic stainless steel. Both stainless steels were heat-treated at 500, 650, and 800 degrees C in air for 1 h, followed by furnace cooling. Each heat-treated sample was examined for their microstructures and Vickers micro-hardness, and subjected to the X-ray diffraction for the phase identification. Using potentiostatic polarization method, each heat-treated sample was corrosion-tested in 37 degrees C 0.9% NaCl solution to estimate its corrosion rate. It was found that simulated sensitization showed an adverse influence on both steels, indicating that corrosion rates increased by increasing the sensitization temperatures.

  4. Duplex stainless steel surface bay laser cladding

    International Nuclear Information System (INIS)

    Amigo, V.; Pineda, Y.; Segovia, F.; Vicente, A.

    2004-01-01

    Laser cladding is one of the most promising techniques to restore damaged surfaces and achieve properties similar to those of the base metal. In this work, duplex stainless steels have been cladded by a nickel alloy under different processing conditions. The influence of the beam speed and defocusing variables ha been evaluated in the microstructure both of the cladding and heat affected zone, HAZ. These results have been correlated to mechanical properties by means of microhardness measurements from cladding area to base metal through the interface. This technique has shown to be very appropriate to obtain controlled mechanical properties as they are determined by the solidification microstructure, originated by the transfer of mass and heat in the system. (Author) 21 refs

  5. Duplex quantum communication through a spin chain

    Science.gov (United States)

    Wang, Zhao-Ming; Bishop, C. Allen; Gu, Yong-Jian; Shao, Bin

    2011-08-01

    Data multiplexing within a quantum computer can allow for the simultaneous transfer of multiple streams of information over a shared medium thereby minimizing the number of channels needed for requisite data transmission. Here, we investigate a two-way quantum communication protocol using a spin chain placed in an external magnetic field. In our scheme, Alice and Bob each play the role of a sender and a receiver as two states, cos((θ1)/(2))0+sin((θ1)/(2))eiφ11 and cos((θ2)/(2))0+sin((θ2)/(2))eiφ21, are transferred through one channel simultaneously. We find that the transmission fidelity at each end of a spin chain can usually be enhanced by the presence of a second party. This is an important result for establishing the viability of duplex quantum communication through spin chain networks.

  6. Numerical Simulation of Duplex Steel Multipass Welding

    Directory of Open Access Journals (Sweden)

    Giętka T.

    2016-12-01

    Full Text Available Analyses based on FEM calculations have significantly changed the possibilities of determining welding strains and stresses at early stages of product design and welding technology development. Such an approach to design enables obtaining significant savings in production preparation and post-weld deformation corrections and is also important for utility properties of welded joints obtained. As a result, it is possible to make changes to a simulated process before introducing them into real production as well as to test various variants of a given solution. Numerical simulations require the combination of problems of thermal, mechanical and metallurgical analysis. The study presented involved the SYSWELD software-based analysis of GMA welded multipass butt joints made of duplex steel sheets. The analysis of the distribution of stresses and displacements were carried out for typical welding procedure as during real welding tests.

  7. Minimum training requirement in ultrasound imaging of peripheral arterial disease.

    Science.gov (United States)

    Eiberg, J P; Hansen, M A; Grønvall Rasmussen, J B; Schroeder, T V

    2008-09-01

    To demonstrate the minimum training requirement when performing ultrasound of peripheral arterial disease. Prospective and blinded comparative study. 100 limbs in 100 consecutive patients suffering from peripheral arterial disease, 74% suffering critical limb ischemia, were enrolled during a 9 months period. One physician with limited ultrasound experience performed all the ultrasound examinations of the arteries of the most symptomatic limb. Before enrolling any patients 15 duplex ultrasound examinations were performed supervised by an experienced vascular technologist. All patients had a digital subtraction arteriography performed by an experienced vascular radiologist, unaware of the ultrasound result. The number of insufficiently insonated segments (non-diagnostic segments) was significantly reduced during the study; from 9% among the initial 50 limbs to 2% among the last 50 limbs (Pultrasound and arteriography from the initial 50 patients (overall Kappa=0.66, (95%-CI: 0.60-0.72); supragenicular Kappa=0.73 (95%-CI: 0.64-0.82); infragenicular Kappa=0.61 (95%-CI: 0.54-0.69)) to the last 50 patients (overall Kappa=0.66 (95%-CI: 0.60-0.72), supragenicular Kappa=0.67 (95%-CI: 0.57-0.76); infragenicular Kappa=0.66 (95%-CI: 0.58-0.73)). The minimum training requirement in ultrasound imaging of peripheral arterial disease appears to be less than 50 ultrasound examinations (probably only 15 examinations) for the supragenicular segments and 100 examinations for the infragenicular segments.

  8. Prostate Ultrasound

    Medline Plus

    Full Text Available ... the prostate. help diagnose the cause of a man's infertility. A transrectal ultrasound of the prostate gland is typically used to help diagnose symptoms such as: a nodule felt by a physician during a routine physical exam or prostate cancer screening exam. an elevated ...

  9. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... and Resources RTAnswers.org Radiation Therapy for Gynecologic Cancers Radiation Therapy for Prostate Cancer top of page This page was reviewed on ... with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. ... Images related to Ultrasound - Pelvis Sponsored by Please ...

  10. Prostate Ultrasound

    Medline Plus

    Full Text Available ... body tissue through which the sound travels. A small amount of gel is put on the skin to allow the sound waves to travel from the transducer to the examined area within the body and then back again. Ultrasound ...

  11. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... body tissue through which the sound travels. A small amount of gel is put on the skin to allow the sound waves to travel from the transducer to the examined area within the body and then back again. Ultrasound ...

  12. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... ultrasound exams are also used to monitor the health and development of an embryo or fetus during pregnancy. See the ... can help to identify and evaluate a variety of urinary and reproductive system disorders in both sexes without x-ray exposure. ...

  13. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... of the reflected sound waves (called the Doppler effect). A computer collects and processes the sounds and creates graphs ... Ultrasound provides real-time imaging, making it a good tool for guiding minimally ... known harmful effects on humans. top of page What are the ...

  14. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician ... blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. ...

  15. Prostate Ultrasound

    Medline Plus

    Full Text Available ... symptoms such as difficulty urinating or an elevated blood test result. It’s also used to investigate a nodule ... exam or prostate cancer screening exam. an elevated blood test result. difficulty urinating. Because ultrasound provides real-time ...

  16. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... in which needles are used to extract a sample of cells from organs for laboratory testing. Doppler ultrasound images can help the physician to see and evaluate: blockages to blood flow (such as clots) narrowing of vessels tumors ...

  17. Prostate Ultrasound

    Medline Plus

    Full Text Available ... exam or prostate cancer screening exam. an elevated blood test result. difficulty urinating. Because ultrasound provides real-time images, it also can be used to guide procedures such as needle biopsies , in which a needle is used to sample cells (tissue) from an abnormal area in the ...

  18. Prostate Ultrasound

    Medline Plus

    Full Text Available ... do not use ionizing radiation (as used in x-rays ), thus there is no radiation exposure to the ... tissues that do not show up well on x-ray images. Ultrasound causes no health problems and may ...

  19. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... do not use ionizing radiation (as used in x-rays ), thus there is no radiation exposure to the ... tissues that do not show up well on x-ray images. Ultrasound is the preferred imaging modality for ...

  20. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... the amplitude (loudness), frequency (pitch) and time it takes for the ultrasound signal to return from the area within the patient that is being examined to the transducer (the device placed on the patient's skin to send and ...

  1. Prostate Ultrasound

    Medline Plus

    Full Text Available ... the amplitude (loudness), frequency (pitch) and time it takes for the ultrasound signal to return from the area within the patient that is being examined to the transducer (the device placed on the patient's skin to send and ...

  2. Ultrasound -- Pelvis

    Medline Plus

    Full Text Available ... the patient. Because ultrasound images are captured in real-time, they can show the structure and movement of ... by a computer, which in turn creates a real-time picture on the monitor. One or more frames ...

  3. Obstetrical ultrasound

    International Nuclear Information System (INIS)

    Bundy, A.L.

    1988-01-01

    The use of diagnostic ultrasound in obstetrics may provide fuel for legal action. While most legal implications of this relatively new imaging modality are purely speculative, some have already given rise to legal action. Several situations will likely provide a basis for the courts to find against the physician. The failure to perform a sonogram when clinically indicated will most likely be the strongest plaintiff argument. Other major concerns include the use and availability of state-of-the-art equipment, as well as interpretation of the scans by a trained physician. Obstetrical ultrasound is usually performed by a radiologist or obstetrician. However, many physicians performing these examinations have had little or no formal training in the field. While this is now being remedied by the respective board examines who require a certain amount of training, it may not be enough. When ultrasound-related cases reach the courts, the involved physicians will most likely be regarded as experts in the field and, therefore, will be held to a very high standard of care. This would be difficult to achieve without formal training. At the present time, the American Board of Radiology requires more training time in ultrasound than the American Board of Obstetrics and Gynecology

  4. Sonography of intrathyroid parathyroid adenomas: Are there distinctive features that allow for preoperative identification?

    International Nuclear Information System (INIS)

    Heller, Matthew T.; Yip, Linwah; Tublin, Mitchell E.

    2013-01-01

    Objective: The purpose of our study was to determine if intra-thyroid parathyroid adenomas can be accurately identified by applying proposed criteria to preoperative ultrasound examinations in patients with primary hyperparathyroidism. Materials/methods: Fifty-three patients with pathology proven intra-thyroid parathyroid adenomas and pre-operative ultrasounds were identified from a surgical database for a blinded, retrospective review. A contemporary, age-matched cohort of 54 patients with extra-thyroid parathyroid adenomas was identified as a control. A total of 64 patients within these cohorts had co-existing thyroid nodules. Proposed ultrasound criteria for identifying a parathyroid adenoma included solid composition, profound hypoechogenicity, and presence of a feeding polar vessel. Parathyroid adenomas were classified as extra-thyroid or intra-thyroid (partial or complete) based on their relationship with the thyroid gland during ultrasound evaluation and results were compared to surgical and histopathology reports as the gold standard. The results from the blinded, retrospective review during which the proposed, specific ultrasound criteria were applied were compared to the initial, pre-operative reports during which the proposed criteria were not applied. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of the blinded, retrospective review and initial, pre-operative reports were calculated. Additionally, in patients with co-existing thyroid nodules, an attempt was made to differentiate parathyroid adenomas from the thyroid nodules. Results: Application of the proposed ultrasound criteria during blinded retrospective review yielded a sensitivity and specificity for detecting intra-thyroid parathyroid adenomas of 76% and 92%, respectively. The sensitivity and specificity of ultrasound for detecting intra-thyroid parathyroid adenomas on the initial reports was 29% and 95%, respectively. The sensitivity and

  5. Venous duplex and pathologic differences in thrombus characteristics between de novo deep vein thrombi and endovenous heat-induced thrombi.

    Science.gov (United States)

    Santin, Brian J; Lohr, Joanne M; Panke, Thomas W; Neville, Patrick M; Felinski, Melissa M; Kuhn, Brian A; Recht, Matthew H; Muck, Patrick E

    2015-04-01

    Superficial venous reflux disease has been treated with endovenous ablation techniques for more than 15 years. Thrombi discovered in the postoperative period are referred to as endovenous heat-induced thrombi (EHIT). In spite of the few studies of the ultrasound differentiation between EHIT and deep vein thrombi (DVT), there remains a paucity of literature regarding the evaluation of ultrasound examination and pathologic differentiation. Six Yorkshire cross swine underwent femoral vein thrombosis by suture ligation or endovenous radiofrequency ablation. At 1 week after the procedure, each femoral vein was imaged by color Duplex ultrasound and sent for histologic interpretation for differentiation between EHIT and DVT. Five blinded vascular surgery faculty, two vascular surgery fellows, and three vascular surgery residents reviewed the ultrasound images. Thrombi associated with radiofrequency ablation demonstrated a greater degree of hypercellular response, fibroblastic reaction, and edema (3.42 vs 2.92; 3.75 vs 2.42; 2.83 vs 1.33). Specimens harvested from the iatrogenic-induced DVT swine demonstrated a more prolific response to trichrome staining (3.42 vs 2.67). Evidence of revascularization was found in all of the EHIT specimens but in 33% of DVT specimens. On the basis of histologic findings, the pathologist predicted correct modality 92% of the time. Subgroup analysis comparing paired specimens from each swine failed to demonstrate any marked pathologic differences. Recorded ultrasound images from EHIT and DVT samples were reviewed by fellows, residents, and vascular surgery staff to determine whether clot was stationary or free-floating (n = 111; 93%), evidence of retracted or adherent vein (n = 105; 88%), and absence of color flow (n = 102; 85%). The degree of occlusion (partial vs total) and degree of distention of a visualized vein were least likely to be agreed on by reviewers (n = 95; 79% each, respectively). In subgroup (DVT vs EHIT) analyses, the

  6. Preoperative diagnosis of carcinoma within fibroadenoma on screening mammograms

    International Nuclear Information System (INIS)

    Borecky, N.; Rickard, M.

    2008-01-01

    Three cases of fibroadenoma associated with carcinoma are reported. These cases were diagnosed within a screening programme as a result of suspicious mammographic findings, and the diagnosis of malignancy was confirmed preoperatively by core biopsy in all cases. The mammographic findings suggestive of carcinoma within fibroadenoma were irregularity of margins in one case and associated new suspicious pleomorphic and linear calcifications in the two other cases. The preoperative diagnosis of carcinoma within fibroadenoma was provided by ultrasound-guided core biopsy in two cases and core biopsy under stereotactic guidance in one case. Whereas asymptomatic fibroadenoma with benign imaging appearances usually does not require further investigation, fibroadenoma with atypical imaging features requires a triple test investigation.

  7. Answer to preoperative chemie radiation in locally advanced rectum cancer

    International Nuclear Information System (INIS)

    Villegas Mendez, Silvia

    2006-01-01

    Study the pre-operative combined therapy effect in the treatment of the rectum cancer cases of the Servicio de Cirugia General 2 of the Hospital Mexico. The study covers since January of 2003 until December of 2005. It has like specific objectives to analyze the effect in the tumour stages, the sphincters preservation and the recurrence. In the conclusions, it notes that the pre-operative chemie-radiation in the rectum cancer is indicated in II and III stages, in which it has showed most advantages for the patient. It describes that the time between the end of pre-operative combined treatment and the surgery must has at least six weeks to guarantee the effect in the tumour and to reduce the treatment toxicity. It concludes besides, that the complication rate after the pre-operative combined therapy and the total meso rectum excision is approximately of 33%; however, the pelvic septic complications can reduce with an ostomy of protection. It focus that the technique of sphincters preservation has showed to be effective and secure if it does a previous selection to the patients in appropriate form. To get an suitable stages must count with trans rectum endoscopic ultrasound and a tomography of suitable quality. It concludes, also, in intervened tumours after of neo-adjuvancy they don't need free distal margins of illness higher to 2 cm. The total meso rectum excision is the updated surgical recommendation in the rectum cancer [es

  8. Preoperative alcoholism and postoperative morbidity

    DEFF Research Database (Denmark)

    Tonnesen, H; Kehlet, H

    1999-01-01

    BACKGROUND: Preoperative risk assessment has become part of daily clinical practice, but preoperative alcohol abuse has not received much attention. METHODS: A Medline search was carried out to identify original papers published from 1967 to 1998. Relevant articles on postoperative morbidity...... in alcohol abusers were used to evaluate the evidence. RESULTS: Prospective and retrospective studies demonstrate a twofold to threefold increase in postoperative morbidity in alcohol abusers, the most frequent complications being infections, bleeding and cardiopulmonary insufficiency. Wound complications...... to postoperative morbidity. CONCLUSION: Alcohol consumption should be included in the preoperative assessment of likely postoperative outcome. Reduction of postoperative morbidity in alcohol abusers may include preoperative alcohol abstinence to improve organ function, or perioperative alcohol administration...

  9. Development of oxide dispersion strengthened 2205 duplex stainless steel composite

    Directory of Open Access Journals (Sweden)

    Oladayo OLANIRAN

    2015-05-01

    Full Text Available Composites of duplex stainless steel were produced by oxide dispersion strengthening with comparatively improved mechanical properties by hot press sintering of partially stabilized Zirconia (PSZ, 3% yttria, mole fraction dispersion in 2205 duplex stainless steels. Ceramic oxide was added as reinforcement, while chromium (Cr and Nickel (Ni were incorporated to maintain the austenitic/ferritic phase balance of the duplex stainless steel. The powders and sintered were characterized in detail using scanning electron microscopy (SEM and X-ray diffraction (XRD. The microstructural evolution and phase formation during oxide dispersion strengthening of duplex stainless steel composites were investigated. The influence of composition variation of the reinforcements on the microstructural and corrosion behaviour in simulated mine water of the composites were investigated. In this manuscript, it was established that composition has great influence on the structure/properties relationship of the composites developed.

  10. Improper Signaling for Virtual Full-Duplex Relay Systems

    KAUST Repository

    Gaafar, Mohamed

    2017-02-14

    Virtual full-duplex (VFD) is a powerful solution to compensate the rate loss of half-duplex relaying without the need to full-duplex capable nodes. Inter-relay interference (IRI) challenges the operation of VFD relaying systems. Recently, improper signaling is employed at both relays of the VFD to mitigate the IRI by imposing the same signal characteristics for both relays. To further boost the achievable rate performance, asymmetric time sharing VFD relaying system is adopted with different improper signals at the half-duplex relays. The joint tuning of the three design parameters improves the achievable rate performance at different ranges of IRI and different relays locations. Extensive simulation results are presented and analyzed to show the achievable rate gain of the proposed system and understand the system behavior.

  11. Improper Signaling for Virtual Full-Duplex Relay Systems

    KAUST Repository

    Gaafar, Mohamed; Amin, Osama; Schaefer, Rafael F.; Alouini, Mohamed-Slim

    2017-01-01

    Virtual full-duplex (VFD) is a powerful solution to compensate the rate loss of half-duplex relaying without the need to full-duplex capable nodes. Inter-relay interference (IRI) challenges the operation of VFD relaying systems. Recently, improper signaling is employed at both relays of the VFD to mitigate the IRI by imposing the same signal characteristics for both relays. To further boost the achievable rate performance, asymmetric time sharing VFD relaying system is adopted with different improper signals at the half-duplex relays. The joint tuning of the three design parameters improves the achievable rate performance at different ranges of IRI and different relays locations. Extensive simulation results are presented and analyzed to show the achievable rate gain of the proposed system and understand the system behavior.

  12. Aortoiliac reconstructive surgery based upon the results of duplex scanning

    NARCIS (Netherlands)

    van der Zaag, E. S.; Legemate, D. A.; Nguyen, T.; Balm, R.; Jacobs, M. J.

    1998-01-01

    OBJECTIVE: To evaluate whether duplex scanning can replace angiography in patients operated for aortoiliac obstructive disease. DESIGN: Retrospective. MATERIALS AND METHODS: Between January 1995 and October 1996, 44 patients underwent vascular surgery of the aortoiliac tract. The study population

  13. A retrospective analysis of preoperative staging modalities for oral squamous cell carcinoma.

    Science.gov (United States)

    Kähling, Ch; Langguth, T; Roller, F; Kroll, T; Krombach, G; Knitschke, M; Streckbein, Ph; Howaldt, H P; Wilbrand, J-F

    2016-12-01

    An accurate preoperative assessment of cervical lymph node status is a prerequisite for individually tailored cancer therapies in patients with oral squamous cell carcinoma. The detection of malignant spread and its treatment crucially influence the prognosis. The aim of the present study was to analyze the different staging modalities used among patients with a diagnosis of primary oral squamous cell carcinoma between 2008 and 2015. An analysis of preoperative staging findings, collected by clinical palpation, ultrasound, and computed tomography (CT), was performed. The results obtained were compared with the results of the final histopathological findings of the neck dissection specimens. A statistical analysis using McNemar's test was performed. The sensitivity of CT for the detection of malignant cervical tumor spread was 74.5%. The ultrasound obtained a sensitivity of 60.8%. Both CT and ultrasound demonstrated significantly enhanced sensitivity compared to the clinical palpation with a sensitivity of 37.1%. No significant difference was observed between CT and ultrasound. A combination of different staging modalities increased the sensitivity significantly compared with ultrasound staging alone. No significant difference in sensitivity was found between the combined use of different staging modalities and CT staging alone. The highest sensitivity, of 80.0%, was obtained by a combination of all three staging modalities: clinical palpation, ultrasound and CT. The present study indicates that CT has an essential role in the preoperative staging of patients with oral squamous cell carcinoma. Its use not only significantly increases the sensitivity of cervical lymph node metastasis detection but also offers a preoperative assessment of local tumor spread and resection borders. An additional non-invasive cervical lymph node examination increases the sensitivity of the tumor staging process and reduces the risk of occult metastasis. Copyright © 2016 European

  14. The role of duplex stainless steels for downhole tubulars

    International Nuclear Information System (INIS)

    Francis, R.

    1993-01-01

    In sour conditions there is an increasing trend to turn to corrosion resistant alloys for downhole tubulars. The most commonly used CRA tubular is 13Cr, and there are thousands of feet in service. However, there are limits to the use of 13Cr, ie., the risk of sulphide stress corrosion cracking at high H 2 S levels, and the possibility of pitting or high corrosion rates in waters with high chloride contents. Where the service conditions are felt to be too severe for 13Cr alloys it has been traditional to switch to nickel base alloys such as alloys 825 and C-276 (UNS N08825 and N10276). The alloys are much more expensive than 13Cr, and in recent years the duplex stainless steels have been selected as alloys with superior corrosion and SSCC resistance compared with 13Cr, and having lower cost than nickel alloys. Originally the 22Cr duplex alloy (UNS 31803) was used, but more recently the 25Cr super duplex alloys (UNS S32760 and S32750) have become more available. The present paper reviews the data available for 13Cr and the limits of applicability. Data is also presented for laboratory tests for both the 22Cr and 25Cr super duplex alloys. There is extensive service experience with both 22Cr and 25Cr super duplex in the North Sea, covering both downhole tubulars, manifold and post wellhead equipment. Data is presented showing some of the sour condition being experienced in the North Sea by super duplex alloys. These results show that there is a substantial gap between the limits of use for 13Cr and the 25Cr super duplex stainless steel alloys. This means that in many sour environments super duplex stainless steel provides a cost effective alternative to nickel-base alloys

  15. Magnetic resonance urography in duplex kidney with ectopic ureteral insertion

    Directory of Open Access Journals (Sweden)

    Conjeevaram Rajendrarao Thambidorai

    2011-01-01

    Full Text Available This is a report on the use of magnetic resonance urography (MRU in a 6-year-old girl who presented with urinary incontinence. She had a left duplex kidney with poorly functioning upper moiety and ectopic insertion of the dilated upper pole ureter. MRU has been shown to be superior to conventional imaging techniques in delineating poorly functioning moieties of duplex kidneys and ectopic ureters.

  16. Transcranial Duplex Sonography Predicts Outcome following an Intracerebral Hemorrhage.

    Science.gov (United States)

    Camps-Renom, P; Méndez, J; Granell, E; Casoni, F; Prats-Sánchez, L; Martínez-Domeño, A; Guisado-Alonso, D; Martí-Fàbregas, J; Delgado-Mederos, R

    2017-08-01

    Several radiologic features such as hematoma volume are related to poor outcome following an intracerebral hemorrhage and can be measured with transcranial duplex sonography. We sought to determine the prognostic value of transcranial duplex sonography in patients with intracerebral hemorrhage. We conducted a prospective study of patients diagnosed with spontaneous intracerebral hemorrhage. Transcranial duplex sonography examinations were performed within 2 hours of baseline CT, and we recorded the following variables: hematoma volume, midline shift, third ventricle and lateral ventricle diameters, and the pulsatility index in both MCAs. We correlated these data with the CT scans and assessed the prognostic value of the transcranial duplex sonography measurements. We assessed early neurologic deterioration during hospitalization and mortality at 1-month follow-up. We included 35 patients with a mean age of 72.2 ± 12.8 years. Median baseline hematoma volume was 9.85 mL (interquartile range, 2.74-68.29 mL). We found good agreement and excellent correlation between transcranial duplex sonography and CT when measuring hematoma volume ( r = 0.791; P duplex sonography measurements showed that hematoma volume was an independent predictor of early neurologic deterioration (OR, 1.078; 95% CI, 1.023-1.135) and mortality (OR, 1.089; 95% CI, 1.020-1.160). A second regression analysis with CT variables also demonstrated that hematoma volume was associated with early neurologic deterioration and mortality. When we compared the rating operation curves of both models, their predictive power was similar. Transcranial duplex sonography showed an excellent correlation with CT in assessing hematoma volume and midline shift in patients with intracerebral hemorrhage. Hematoma volume measured with transcranial duplex sonography was an independent predictor of poor outcome. © 2017 by American Journal of Neuroradiology.

  17. On the Secrecy Degrees of Freedom with Full-Duplex Communication

    DEFF Research Database (Denmark)

    Mahmood, Nurul Huda; Mogensen, Preben Elgaard

    2017-01-01

    of such an application. The potential of full duplex nodes in improving the physical layer security of a communication link is investigated in this contribution. We specifically derive the information theoretic secrecy degrees of freedom measure for a pair of nodes communicating in full duplex mode. Moreover, closed...... and the delay reduction of full duplex communication are somewhat limited in realistic network settings, leading researchers to study other possible applications of full duplex communication which can provide significantly higher gains over half duplex communication. Physical layer security is an example...... form expressions for the instantaneous and ergodic throughput gain of full duplex communication over conventional half duplex is derived. The secrecy degrees of freedom with full duplex is shown to be two as opposed to that of zero in half duplex mode....

  18. EFFECT OF INTERMETALLIC PHASES ON CORROSION BEHAVIOR AND MECHANICAL PROPERTIES OF DUPLEX STAINLESS STEEL AND SUPER-DUPLEX STAINLESS STEEL

    OpenAIRE

    Prabhu Paulraj; Rajnish Garg

    2015-01-01

    Duplex Stainless Steels (DSS) and Super Duplex Stainless Steel (SDSS) have excellent integration of mechanical and corrosion properties. However, the formation of intermetallic phases is a major problem in their usage. The mechanical and corrosion properties are deteriorated due to the presence of intermetallic phases. These phases are induced during welding, prolonged exposure to high temperatures, and improper heat treatments. The main emphasis of this review article is on intermetallic pha...

  19. Predictors of diagnostic success with renal artery duplex ultrasonography.

    Science.gov (United States)

    Hedayati, Nasim; Del Pizzo, David J; Harris, Sean E; Kuskowski, Michael; Pevec, William C; Lee, Eugene S; Pifer, Christy; Dawson, David L

    2011-05-01

    Renal artery duplex ultrasonography (RA-DUS) is commonly used for the evaluation and follow-up of renal artery atherosclerotic disease. In a complete study, renal artery flow is evaluated from the vessel origin to the intraparenchymal branches. The quality of RA-DUS is in part technologist-dependent, but many factors may affect the ability to complete a diagnostic examination. This study evaluated the clinical and technical factors that predict the ability to obtain a complete RA-DUS examination. A prospective evaluation of all patients undergoing RA-DUS between July 2008 and February 2009 was performed. Factors such as patient age, gender, body mass index, technologists' years of experience, patient care setting (inpatient vs. outpatient), bedside examination, smoking before the examination, fasting status, and recent abdominal surgery were all recorded. Multivariate logistic regression analysis was performed. A p value of ≤ 0.05 was considered significant. During the study period, 250 patients underwent RA-DUS (mean age: 59.9 ± 17.8 years, 57% [143] female). A total of 87 (35%) examinations were incomplete. This included nondiagnostic examinations which did not exhibit any segment of the renal artery. Factors that were associated with an incomplete examination included technologists' years of experience (OR = 0.92, p = 0.042), bedside examination (OR = 4.17, p = 0.016), and recent abdominal surgery (OR = 3.45, p = 0.047). Body mass index, fasting status, and smoking before the examination did not affect the ability to obtain a complete study. One-third of the RA-DUS studies were classified as incomplete by the strict criteria used in this prospective study. An experienced ultrasound technologist is more likely to obtain a complete RA-DUS examination. Recent abdominal surgery and bedside examinations were predictive of a limited examination as well. Vascular laboratories should consider these factors when scheduling examinations so as to obtain complete RA

  20. Phase Transformations in Cast Duplex Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yoon-Jun [Iowa State Univ., Ames, IA (United States)

    2004-01-01

    Duplex stainless steels (DSS) constitute both ferrite and austenite as a matrix. Such a microstructure confers a high corrosion resistance with favorable mechanical properties. However, intermetallic phases such as σ and χ can also form during casting or high-temperature processing and can degrade the properties of the DSS. This research was initiated to develop time-temperature-transformation (TTT) and continuous-cooling-transformation (CCT) diagrams of two types of cast duplex stainless steels, CD3MN (Fe-22Cr-5Ni-Mo-N) and CD3MWCuN (Fe-25Cr-7Ni-Mo-W-Cu-N), in order to understand the time and temperature ranges for intermetallic phase formation. The alloys were heat treated isothermally or under controlled cooling conditions and then characterized using conventional metallographic methods that included tint etching, and also using electron microscopy (SEM, TEM) and wavelength dispersive spectroscopy (WDS). The kinetics of intermetallic-phase (σ + χ) formation were analyzed using the Johnson-Mehl-Avrami (MA) equation in the case of isothermal transformations and a modified form of this equation in the case of continuous cooling transformations. The rate of intermetallic-phase formation was found to be much faster in CD3MWCuN than CD3MN due mainly to differences in the major alloying contents such as Cr, Ni and Mo. To examine in more detail the effects of these elements of the phase stabilities; a series of eight steel castings was designed with the Cr, Ni and Mo contents systematically varied with respect to the nominal composition of CD3MN. The effects of varying the contents of alloying additions on the formation of intermetallic phases were also studied computationally using the commercial thermodynamic software package, Thermo-Calc. In general, σ was stabilized with increasing Cr addition and χ by increasing Mo addition. However, a delicate balance among Ni and other minor elements such as N and Si also exists. Phase equilibria in DSS can be affected by

  1. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... of page How is the procedure performed? For most ultrasound exams, you will be positioned lying face- ... Ultrasound examinations are painless and easily tolerated by most patients. Ultrasound exams in which the transducer is ...

  2. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... ultrasound. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... modality for the diagnosis and monitoring of pregnant women and their unborn babies. Ultrasound provides real-time ...

  3. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... medical test that helps physicians diagnose and treat medical conditions. Conventional ultrasound displays the images in thin, flat sections of the body. Advancements in ultrasound technology include three-dimensional (3-D) ultrasound that formats ...

  4. Ultrasound guided supraclavicular block.

    LENUS (Irish Health Repository)

    Hanumanthaiah, Deepak

    2013-09-01

    Ultrasound guided regional anaesthesia is becoming increasingly popular. The supraclavicular block has been transformed by ultrasound guidance into a potentially safe superficial block. We reviewed the techniques of performing supraclavicular block with special focus on ultrasound guidance.

  5. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... D images. A Doppler ultrasound study may be part of an ultrasound examination. Doppler ultrasound , also called ... terms of the distance traveled per unit of time, rather than as a color picture. It can ...

  6. The Role of Airway and Endobronchial Ultrasound in Perioperative Medicine

    Directory of Open Access Journals (Sweden)

    Jiri Votruba

    2015-01-01

    Full Text Available Recent years have witnessed an increased use of ultrasound in evaluation of the airway and the lower parts of the respiratory system. Ultrasound examination is fast and reliable and can be performed at the bedside and does not carry the risk of exposure to ionizing radiation. Apart from use in diagnostics it may also provide safe guidance for invasive and semi-invasive procedures. Ultrasound examination of the oral cavity structures, epiglottis, vocal cords, and subglottic space may help in the prediction of difficult intubation. Preoperative ultrasound may diagnose vocal cord palsy or deviation or stenosis of the trachea. Ultrasonography can also be used for confirmation of endotracheal tube, double-lumen tube, or laryngeal mask placement. This can be achieved by direct examination of the tube inside the trachea or by indirect methods evaluating lung movements. Postoperative airway ultrasound may reveal laryngeal pathology or subglottic oedema. Conventional ultrasound is a reliable real-time navigational tool for emergency cricothyrotomy or percutaneous dilational tracheostomy. Endobronchial ultrasound is a combination of bronchoscopy and ultrasonography and is used for preoperative examination of lung cancer and solitary pulmonary nodules. The method is also useful for real-time navigated biopsies of such pathological structures.

  7. Corrosion behaviour of sintered duplex stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Utrilla, M. Victoria; Urena, Alejandro; Otero, Enrique; Munez, Claudio Jose [Escuela Superior de Ciencias Experimentales y Tecnologia, Universidad Rey Juan Carlos, C/ Tulipan s/n, 28933 Mostoles, Madrid (Spain)

    2004-07-01

    Duplex austenite-ferrite stainless steels were prepared by mixing austenitic (316L) and ferritic (434L) atomized powders. Although different 316L/434L ratios were prepared, present work centred its study on 50% ferrite - 50% austenite sintered steel. The powders were mixed and pressed at 700 MPa and sintered at 1250 deg. C for 30 min in vacuum. The cooling rate was 5 deg. C/min. Solution treatment was carried out to homogenize the microstructure at 1100 deg. C during 20 min. A microstructural study of the material in solution was performed, evaluating the microstructure, proportion and shape of porosity, and ferrite percentage. This last was measured by two methods, quantitative metallography and Fischer ferrito-metry. The materials were heat treated in the range of 700 to 1000 deg. C, for 10, 30 and 60 min and water quenched, to study the microstructural changes and the influence on the intergranular corrosion resistance. The method used to evaluate the sensitization to the intergranular corrosion was the electrochemical potentio-kinetic reactivation procedure (EPR). The test solution was 0.5 M H{sub 2}SO{sub 4} + 0,01 M KSCN at 30 deg. C. The criterion used to evaluate the sensitization was the ratio between the maximum reactivation density (Ir) and the maximum activation density (Ia). The results of the electrochemical tests were discussed in relation with the microstructures observed at the different heat treatments. (authors)

  8. Interventions for preoperative smoking cessation

    DEFF Research Database (Denmark)

    Thomsen, Thordis; Villebro, Nete; Møller, Ann Merete

    2014-01-01

    BACKGROUND: Smokers have a substantially increased risk of postoperative complications. Preoperative smoking intervention may be effective in decreasing this incidence, and surgery may constitute a unique opportunity for smoking cessation interventions. OBJECTIVES: The objectives of this review...... are to assess the effect of preoperative smoking intervention on smoking cessation at the time of surgery and 12 months postoperatively, and on the incidence of postoperative complications. SEARCH METHODS: We searched the Cochrane Tobacco Addiction Group Specialized Register in January 2014. SELECTION CRITERIA......: Randomized controlled trials that recruited people who smoked prior to surgery, offered a smoking cessation intervention, and measured preoperative and long-term abstinence from smoking or the incidence of postoperative complications or both outcomes. DATA COLLECTION AND ANALYSIS: The review authors...

  9. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. Conventional ultrasound displays the images in thin, ...

  10. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... and treat medical conditions. Conventional ultrasound displays the images in thin, flat sections of the body. Advancements in ultrasound technology include three-dimensional (3- ...

  11. Preoperative staging of rectal cancer.

    Science.gov (United States)

    Smith, Neil; Brown, Gina

    2008-01-01

    Detailed preoperative staging using high resolution magnetic resonance imaging (MRI) enables the selection of patients that require preoperative therapy for tumour regression. This information can be used to instigate neoadjuvant therapy in those patients with poor prognostic features prior to disturbing the tumour bed and potentially disseminating disease. The design of trials incorporating MR assessment of prognostic factors prior to therapy has been found to be of value in assessing treatment modalities and outcomes that are targeted to these preoperative prognostic subgroups and in providing a quantifiable assessment of the efficacy of particular chemoradiation treatment protocols by comparing pre-treatment MR staging with post therapy histology assessment. At present, we are focused on achieving clear surgical margins of excision (CRM) to avoid local recurrence. We recommend that all patients with rectal cancer should undergo pre-operative MRI staging. Of these, about half will have good prognosis features (T1-T3b, N0, EMVI negative, CRM clear) and may safely undergo primary total mesorectal excision. Of the remainder, those with threatened or involved margins will certainly benefit from pre-operative chemoradiotherapy with the aim of downstaging to permit safe surgical excision. In the future, our ability to recognise features predicting distant failure, such as extramural vascular invasion (EMVI) may be used to stratify patients for neo-adjuvant systemic chemotherapy in an effort to prevent distant relapse. The optimal pre-operative treatment regimes for these patients (radiotherapy alone, systemic chemotherapy alone or combination chemo-radiotherapy) is the subject of current and future trials.

  12. Preoperative fasting: a clinical audit.

    Science.gov (United States)

    Roberts, Stuart

    2013-01-01

    This clinical audit examines the adherence to guidelines suggested by the Royal College of Nursing (2005); the results uphold previous studies of a preoperative starving period for patients undergoing elective surgical procedures. Patients excessively starved of food or fluids report problems relating to their health. These include hunger, distress and complaints of nausea.

  13. MRI, CT, and sonography in the preoperative evaluation of primary tumor extension in malignant pleural mesothelioma

    International Nuclear Information System (INIS)

    Layer, G.; Steudel, A.; Schild, H.H.; Schmitteckert, H.; Tuengerthal, S.; Schirren, J.; Kaick, G. van

    1999-01-01

    Purpose: Evaluation of the diagnostic value of the imaging modalities computed tomography (CT), magnetic resonance imaging (MRI), and thoracic sonography in the preoperative staging of malignant pleural mesothelioma. Results: The accuracy rates for CT were 85%, 98%, 83%, 73%, 71%, and 83%. MRI had an accuracy of 71%, 92%, 71%, 83%, 71%, and 96%, the thoracic ultrasound examinations of 76%, 63%, 51%, 60%, 71% and 89%. Conclusions: According to these results CT remains the method of choice in the preoperative assessment of T-stage of malignant pleural mesothelioma. MRI is of nearly the same value, but is not a must. Sonography may be supplementary method for operation planning. (orig./AJ) [de

  14. THE INFLUENCE OF POSTHEAT TREATMENT ON FERRITE REDISTRIBUTION IN DUPLEX STEELS ELECTRON BEAM WELDS

    OpenAIRE

    Zita Iždinská; František Kolenič

    2009-01-01

    The duplex stainless steel is two-phase steel with the structure composed of austenite and ferrite with optimum austenite/ferrite proportion 50%. At present, classical arc processes for welding duplex steels are generally regarded as acceptable. On the other hand electron and laser beam welding is up to now considered less suitable for welding duplex steels. The submitted work presents the results of testing various thermal conditions at welding duplex stainless steel with electron beam. It w...

  15. [Design of a preoperative predictive score for choledocholithiasis].

    Science.gov (United States)

    Bueno Lledó, Jose; Ibáñez Cirión, Jose Luis; Torregrosa Gallud, Antonio; López Andújar, Rafael

    2014-11-01

    Choledocholithiasis is the most common cause of obstructive jaundice and occurs in 5-10% of patients with cholelithiasis. To design a preoperative predictive score for choledocholithiasis. A prospective study was carried out in 556 patients admitted to our department for biliary disease. Preoperative clinical, laboratory, and ultrasound variables were compared between patients without choledocholithiasis and 65 patients with this diagnosis. A multivariate logistic analysis was performed to obtain a predictive model of choledocholithiasis, determining sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Predictors of choledocholithiasis were the presence of a prior history of biliary disease (history of biliary colic, acute cholecystitis, choledocholithiasis or acute biliary pancreatitis) (p=0.021, OR=2.225, 95% CI: 1.130-4.381), total bilirubin values >4mg/dl (p=0.046, OR=2.403, 95% CI: 1.106-5.685), alkaline phosphatase values >150mg/dl (p=0.022 income, OR=2.631, 95%: 1.386-6.231), gamma-glutamyltransferase (GGT) values >100mg/dl (p=0.035, OR=2.10, 95% CI: 1.345-5.850), and an ultrasound finding of biliary duct >8mm (p=0.034, OR=3.063 95% CI: 1086-8649). A score superior to 5 had a specificity and PPV of 100% for detecting choledocholithiasis and a score less than 3 had a sensitivity and NPV of 100% for excluding this diagnosis. The preoperative score can exclude or confirm the presence of choledocholithiasis and allows patients to directly benefit from laparoscopic cholecystectomy (LC) or prior endoscopic retrograde cholangiopancreatography (ERCP). Copyright © 2014 Elsevier España, S.L.U. and AEEH y AEG. All rights reserved.

  16. Accuracy of Carotid Duplex Criteria in Diagnosis of Significant Carotid Stenosis in Asian Patients.

    Science.gov (United States)

    Dharmasaroja, Pornpatr A; Uransilp, Nattaphol; Watcharakorn, Arvemas; Piyabhan, Pritsana

    2018-03-01

    Extracranial carotid stenosis can be diagnosed by velocity criteria of carotid duplex. Whether they are accurately applied to define severity of internal carotid artery (ICA) stenosis in Asian patients needs to be proved. The purpose of this study was to evaluate the accuracy of 2 carotid duplex velocity criteria in defining significant carotid stenosis. Carotid duplex studies and magnetic resonance angiography were reviewed. Criteria 1 was recommended by the Society of Radiologists in Ultrasound; moderate stenosis (50%-69%): peak systolic velocity (PSV) 125-230 cm/s, diastolic velocity (DV) 40-100 cm/s; severe stenosis (>70%): PSV greater than 230 cm/s, DV greater than 100 cm/s. Criteria 2 used PSV greater than 140 cm/s, DV less than 110 cm/s to define moderate stenosis (50%-75%) and PSV greater than 140 cm/s, DV greater than 110 cm/s for severe stenosis (76%-95%). A total of 854 ICA segments were reviewed. There was moderate stenosis in 72 ICAs, severe stenosis in 50 ICAs, and occlusion in 78 ICAs. Criteria 2 had slightly lower sensitivity, whereas higher specificity and accuracy than criteria 1 were observed in detecting moderate stenosis (criteria 1: sensitivity 95%, specificity 83%, accuracy 84%; criteria 2: sensitivity 92%, specificity 92%, and accuracy 92%). However, in detection of severe ICA stenosis, no significant difference in sensitivity, specificity, and accuracy was found (criteria 1: sensitivity 82%, specificity 99.57%, accuracy 98%; criteria 2: sensitivity 86%, specificity 99.68%, and accuracy 99%). In the subgroup of moderate stenosis, the criteria using ICA PSV greater than 140 cm/s had higher specificity and accuracy than the criteria using ICA PSV 125-230 cm/s. However, there was no significant difference in detection of severe stenosis or occlusion of ICA. Copyright © 2018 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  17. Analysing Self Interference Cancellation in Full Duplex Radios

    DEFF Research Database (Denmark)

    Mahmood, Nurul Huda; Shafique Ansari, Imran; Berardinelli, Gilberto

    2016-01-01

    Full duplex communication promises a theoretical $100\\%$ throughput gain by doubling the number of simultaneous transmissions. Such compelling gains are conditioned on perfect cancellation of the self interference power resulting from simultaneous transmission and reception. Generally, self...... interference power is modelled as a noise-like constant level interference floor. However, experimental validations have shown that the self interference power is in practice a random variable depending on a number of factors such as the surrounding wireless environment and the degree of interference...... cancellation. In this study, we derive an analytical model for the residual self interference power, and demonstrate various applications of the derived model in analysing the performance of a Full Duplex radio. In general, full duplex communication is found to provide only modest throughput gains over half...

  18. CMOS serial link for fully duplexed data communication

    Science.gov (United States)

    Lee, Kyeongho; Kim, Sungjoon; Ahn, Gijung; Jeong, Deog-Kyoon

    1995-04-01

    This paper describes a CMOS serial link allowing fully duplexed 500 Mbaud serial data communication. The CMOS serial link is a robust and low-cost solution to high data rate requirements. A central charge pump PLL for generating multiphase clocks for oversampling is shared by several serial link channels. Fully duplexed serial data communication is realized in the bidirectional bridge by separating incoming data from the mixed signal on the cable end. The digital PLL accomplishes process-independent data recovery by using a low-ratio oversampling, a majority voting, and a parallel data recovery scheme. Mostly, digital approach could extend its bandwidth further with scaled CMOS technology. A single channel serial link and a charge pump PLL are integrated in a test chip using 1.2 micron CMOS process technology. The test chip confirms upto 500 Mbaud unidirectional mode operation and 320 Mbaud fully duplexed mode operation with pseudo random data patterns.

  19. Features of residual stresses in duplex stainless steel butt welds

    Science.gov (United States)

    Um, Tae-Hwan; Lee, Chin-Hyung; Chang, Kyong-Ho; Nguyen Van Do, Vuong

    2018-04-01

    Duplex stainless steel finds increasing use as an alternative to austenitic stainless steel, particularly where chloride or sulphide stress corrosion cracking is of primary concern, due to the excellent combination of strength and corrosion resistance. During welding, duplex stainless steel does not create the same magnitude or distribution of weld-induced residual stresses as those in welded austenitic stainless steel due to the different physical and mechanical properties between them. In this work, an experimental study on the residual stresses in butt-welded duplex stainless steel is performed utilizing the layering technique to investigate the characteristics of residual stresses in the weldment. Three-dimensional thermos-mechanical-metallurgical finite element analysis is also performed to confirm the residual stress measurements.

  20. Blood velocity estimation using ultrasound and spectral iterative adaptive approaches

    DEFF Research Database (Denmark)

    Gudmundson, Erik; Jakobsson, Andreas; Jensen, Jørgen Arendt

    2011-01-01

    -mode images are interleaved with the Doppler emissions. Furthermore, the techniques are shown, using both simplified and more realistic Field II simulations as well as in vivo data, to outperform current state-of-the-art techniques, allowing for accurate estimation of the blood velocity spectrum using only 30......This paper proposes two novel iterative data-adaptive spectral estimation techniques for blood velocity estimation using medical ultrasound scanners. The techniques make no assumption on the sampling pattern of the emissions or the depth samples, allowing for duplex mode transmissions where B...

  1. Comparison of simulated and measured quantities of a duplex reactor

    Energy Technology Data Exchange (ETDEWEB)

    Koskela, M.; Kajava, M. [ABB Marine, Helsinki (Finland)

    1997-12-31

    The purpose of this article is to illustrate the use of an analog simulator as a design tool when designing new power electric equipment. The purpose of simulation is to predict the functionality of electrical equipment to be constructed. Duplex reactor is an electromagnetic device designed to reduce voltage harmonics and short circuit currents in the ship electrical network. In this report a comparison between simulated and measured electrical quantities of a duplex reactor has been made. The purpose of the measurements was to show the correct functioning of the reactor. The simulation results and the measured waveforms corresponds well to each other. (orig.) 4 refs.

  2. Mechanical properties of welded joints of duplex steels

    International Nuclear Information System (INIS)

    Kawiak, M.; Nowacki, J.

    2003-01-01

    The paper presents the study results of mechanical properties of duplex steels UNS S31803 welded joints as well as duplex and NV A36 steels welded joints. They have ben welded by FCAW method in CO 2 using FCW 2205-H flux-cored wire. The joints have been subjected: tensile tests, impact tests, bending tests, hardness tests and metallographic investigations. The influence of welding parameters and mechanical properties of the joints was appreciated. The welding method assured high tensile strength of the joints (approximately 770 MPa) and high impact strength of the welds (approximately 770 J). All samples were broken outside of welds. (author)

  3. Duplex sonography of the near-surface leg veins

    International Nuclear Information System (INIS)

    Mendoza, E.

    2007-01-01

    The book contains the following contributions: The ultrasonograph, selection of the ultrasonic transducer, anatomy of the near-surface vein system, physiology of the near-surface vein system, varicose status classification, systematics of the duplex sonography of near-surface leg veins, provocational maneuver for the duplex sonographic varicose diagnostics, exploration of vena saphena parva, perforans veins, side branches, phlebitis, sonography for varicose therapy, postsurgical sonography, deep leg veins, examination of near-surface leg veins for the pathology of the deep vein system, differential diagnostic clarification of leg oedema from the phlebologic-lymphological view, diagnostic side features along the near-surface leg veins

  4. Pre-operative evaluation for thorax surgery

    International Nuclear Information System (INIS)

    Silva Luis, Saenz; Morales, Oscar Alberto

    2002-01-01

    A pre-operative analysis of the function of the breathing system is made in the patient that will be taken to thorax surgery. The paper includes risk factors, pre-operative clinical evaluation and of breathing and cardiovascular system

  5. Ultrasound in Space Medicine

    Science.gov (United States)

    Dulchavsky, Scott A.; Sargsyan, A.E.

    2009-01-01

    This slide presentation reviews the use of ultrasound as a diagnostic tool in microgravity environments. The goals of research in ultrasound usage in space environments are: (1) Determine accuracy of ultrasound in novel clinical conditions. (2) Determine optimal training methodologies, (3) Determine microgravity associated changes and (4) Develop intuitive ultrasound catalog to enhance autonomous medical care. Also uses of Ultrasound technology in terrestrial applications are reviewed.

  6. Comparison of ultrasound and computed tomography in staging of bladder cancer

    International Nuclear Information System (INIS)

    Suyama, Bunzo

    1982-01-01

    Preoperative staging of bladder cancer is very important for decision of treating methods and prognostication. The present author used ultrasound via the abdominal wall in the diagnosis of 83 patients with bladder cancer. I estimated the extent of bladder tumor infiltration by ultrasound via the abdominal wall according to Shiraishi's criteria. Ultrasound scans, pelvic angiograms and CT scans were reviewed to determine their accuracy in staging of bladder tumors. Ultrasound scans were excellent in staging of non-infiltrated bladder tumors, while pelvic angiograms and CT scans were excellent in staging of infiltrated bladder tumors. (author)

  7. The role of contrast-enhanced ultrasound in risk assessment of carotid atheroma

    Directory of Open Access Journals (Sweden)

    Silviu Stanciu

    2016-07-01

    Full Text Available Background and objective: Contrast-enhanced ultrasound, used to assess atherosclerotic carotid plaques, improves visualization of vessel wall irregularities and depicts intraplaque neovascularization. This article illustrates the use of contrast-enhanced ultrasound in the risk assessment of carotid atherosclerotic lesions, especially in challenging plaques evaluation. Materials and methods: For 23 patients with difficult duplex ultrasound examination due to carotid tortuosity or calcifications we assessed plaque morphology (contour, echogenicity and stenosis degree using contrast substance (Sonovue, Braco with dedicated vascular low mechanical index CPC software. Conclusion: Contrast-enhanced ultrasound is a new, noninvasive, and safe procedure for imaging carotid atherosclerotic lesions. It is a valuable tool for evaluating the vulnerable plaque at risk for rupture and for the diagnostic of the development and severity of systemic atherosclerotic disease

  8. Preoperative staging of rectal cancer

    International Nuclear Information System (INIS)

    Schaefer, A.O.; Baumann, T.; Pache, G.; Langer, M.; Wiech, T.

    2007-01-01

    Accurate preoperative staging of rectal cancer is crucial for therapeutic decision making, as local tumor extent, nodal status, and patterns of metastatic spread are directly associated with different treatment strategies. Recently, treatment approaches have been widely standardized according to large studies and consensus guidelines. Introduced by Heald, total mesorectal excision (TME) is widely accepted as the surgical procedure of choice to remove the rectum together with its enveloping tissues and the mesorectal fascia. Neoadjuvant radiochemotherapy also plays a key role in the treatment of locally advanced stages, while the use of new drugs will lead to a further improvement in oncological outcome. Visualization of the circumferential resection margin is the hallmark of any preoperative imaging and a prerequisite for high-quality TME surgery. The aim of this article is to present an overview on current cross-sectional imaging with emphasis on magnetic resonance imaging. Future perspectives in rectal cancer imaging are addressed. (orig.)

  9. Interventions for preoperative smoking cessation

    DEFF Research Database (Denmark)

    Thomsen, Thordis; Villebro, N.; Møller, Ann Merete

    2010-01-01

    Background Smokers have a substantially increased risk of postoperative complications. Preoperative smoking intervention may be effective in decreasing this incidence, and surgery may constitute a unique opportunity for smoking cessation interventions. Objectives The objective of this review...... was to assess the effect of preoperative smoking intervention on smoking cessation at the time of surgery and 12 months postoperatively and on the incidence of postoperative complications. Search strategy The specialized register of the Cochrane Tobacco Addiction Group was searched using the free text...... and keywords (surgery) or (operation) or (anaesthesia) or (anesthesia). MEDLINE, EMBASE and CINAHL were also searched, combining tobacco- and surgery-related terms. Most recent search April 2010. Selection criteria Randomized controlled trials that recruited people who smoked prior to surgery, offered...

  10. FFTF preoperational survey. Program report

    International Nuclear Information System (INIS)

    Twitty, B.L.; Bicehouse, H.J.

    1980-12-01

    The FFTF will become operational with criticality early in 1980. This facility is composed of the test reactor, fuel examination cells, expended fuel storage systems and fuel handling systems. The reactor and storage systems are sodium-cooled with the heat load dumped to the ambient air through heat exchangers. In order to assure that the operation of the FFTF has minimal impact on the environment, a monitoring program has been established. Prior to operation of a new facility, a preoperational environmental survey is required. It is the purpose of this report to briefly describe the environmental survey program and to provide the background data obtained during the preoperational phase of the survey program. Nine stations in the program of particular importance to FFTF are discussed in detail with results of monitoring given. No unexplained trends were noted

  11. The value of preoperative planning.

    Science.gov (United States)

    Graves, Matt L

    2013-10-01

    "Better to throw your disasters into the waste paper basket than to consign your patients to the scrap heap" has been a proverb of Jeff Mast, one of the greatest fracture and deformity surgeons in the history of our specialty. Stated slightly more scientifically, one of the major values of simulation is that it allows one to make mistakes in a consequence-free environment. Preoperative planning is the focus of this article. The primary goal is not to provide you with a recipe of how to steps. Rather, the primary goal of this article is to explain why preoperative planning should be standard, to clarify what should be included, and to provide examples of what can happen when planning is ignored. At the end of this, we should all feel the need to approach fracture care more intellectually with forethought, both in our own practices and in our educational system.

  12. [Preoperative fasting guidelines: an update].

    Science.gov (United States)

    López Muñoz, A C; Busto Aguirreurreta, N; Tomás Braulio, J

    2015-03-01

    Anesthesiology societies have issued various guidelines on preoperative fasting since 1990, not only to decrease the incidence of lung aspiration and anesthetic morbidity, but also to increase patient comfort prior to anesthesia. Some of these societies have been updating their guidelines, as such that, since 2010, we now have 2 evidence-based preoperative fasting guidelines available. In this article, an attempt is made to review these updated guidelines, as well as the current instructions for more controversial patients such as infants, the obese, and a particular type of ophthalmic surgery. Copyright © 2014 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

  13. Preoperative nutrition therapy - novel developments

    OpenAIRE

    Ljungqvist, Olle; Nygren, Jonas; Hausel, Jonatan; Thorell, Anders

    2000-01-01

    Elective surgery has until recently been performed in the overnight fasted state in order to reduce the risk of aspiration of gastric content during the induction of anaesthesia. However, in order to increase the preoperative well-being of surgical patients, most western countries have changed their routines during the last 10-15 years, allowing intake of clear fluids up to 2 hours before anaesthesia in most patients. Animal studies have demonstrated that undergoing different situations of st...

  14. Robot-assisted laparoscopic pyeloureterostomy in infants with duplex systems and upper pole hydronephrosis: Variations in double-J ureteral stenting techniques.

    Science.gov (United States)

    Baek, Minki; Au, Jason; Huang, Gene O; Koh, Chester J

    2017-04-01

    We describe our experience with robot-assisted laparoscopic (RAL) pyeloureterostomy in infants with duplex systems and upper pole hydronephrosis with an emphasis on the various double J (DJ) ureteral stent placement techniques. We used our RAL pyeloureterostomy technique in two female infants with duplex systems and upper pole hydronephrosis. For case 1, we introduced the DJ stent and placed it in the recipient lower pole ureter during the robotic operation in an antegrade fashion. For case 2, we inserted the DJ stent during retrograde pyelography prior to the robotic procedure in a retrograde fashion, and the proximal portion of the stent was placed across the anastomosis into the upper pole renal pelvis. Postoperatively, each of the patients were discharged on postoperative day 1 without complications. The postoperative renal ultrasound at 3 months demonstrated marked improvement of the right upper pole hydronephrosis in both patients. RAL pyeloureterostomy represents a minimally invasive option for upper tract reconstruction of duplex systems with upper pole hydronephrosis in infants. The DJ stent can be placed at the beginning or during the procedure. The stent can be placed in the lower pole ureter or across the anastomosis into the upper pole renal pelvis. Copyright © 2017 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

  15. Optimisation of welding procedures for duplex and superduplex stainless steels

    International Nuclear Information System (INIS)

    Westin, Elin M.

    2014-01-01

    Austenitic stainless steels are increasingly being replaced by duplex grades that can offer similar corrosion resistance with far higher strength. This increased strength makes it possible to reduce material consumption whilst also decreasing transport and construction costs. Although established welding methods used for austenitic steels can be used for duplex steels, modification of the procedures can lead to improved results. This paper reviews the welding of duplex stainless steel and examines precautions that may be required. The advantages and disadvantages of different welding methods are highlighted and some high productivity solutions are presented. The application of a more efficient process with a high deposition rate (e.g. flux- cored arc welding) can decrease labour costs. Further close control of heat input and interpass temperature can result in more favourable microstructures and final properties. Although welding adversely affects the corrosion resistance of austenitic and duplex stainless steels, particularly the pitting resistance, relative to the parent material, this problem can be minimised by proper backing gas protection and subsequent pickling.

  16. A most spectrum-efficient duplexing system: CDD

    Science.gov (United States)

    Lee, William C. Y.

    2001-10-01

    The game to play in wireless communications when it comes to increasing spectrum efficiency is to eliminate interference. Currently, all cellular systems use FDD (Frequency Division Duplexing) in an attempt to eliminate the interference from the adjacent cells. Through the use of many technologies only one type of interference remains and that is the adjacent base-tohome mobile interference. TDD (Time Division Duplexing) has not been used for mobile cellular systems, not only because of the adjacent base-to-home mobile interference, but also because of the additional adjacent base-to-home base interference, and adjacent mobile-to-home mobile interference. Therefore, TDD can only be used for small, confined area systems. CDD (Code Division Duplexing) can eliminate all three kinds of interference; the adjacent base-to-home mobile, the adjacent baseto-home base, and the adjacent mobile- to- home in cellular systems. Eliminating each of these interferences makes CDD the most spectrum efficient duplexing system. This talk will elaborate on a set of smart codes, which will make an efficient CDD system a reality.

  17. Increased Y-chromosome detection by SRY duplexing

    DEFF Research Database (Denmark)

    Hansen, Morten Høgh; Clausen, Frederik Banch; Dziegiel, Morten Hanefeld

    2012-01-01

    Determining fetal sex noninvasively is dependent of a robust assay. We designed a novel SRY assay and combined it with a SRY assay from literature forming a duplex assay with the same fluorescent dye to increase detection of Y-chromosome at low cell-free fetal DNA or chimeric DNA concentrations....

  18. Full-Duplex Relay Selection in Cognitive Underlay Networks

    KAUST Repository

    Khafagy, Mohammad Galal

    2017-09-30

    In this work, we analyze the performance of full-duplex relay selection (FDRS) in spectrum-sharing networks. Contrary to half-duplex relaying, full-duplex relaying (FDR) enables simultaneous listening/forwarding at the secondary relay(s), thereby allowing for a higher spectral efficiency. However, since the source and relay simultaneously transmit in FDR, their superimposed signal at the primary receiver should now satisfy the existing interference constraint, which can considerably limit the secondary network throughput. In this regard, relay selection can offer an adequate solution to boost the secondary throughput while satisfying the imposed interference limit. We first analyze the performance of opportunistic FDRS with residual self-interference (RSI) by deriving the exact cumulative distribution function of its end-to-end signal-to-interference-plus-noise ratio under Nakagami-m fading. We also evaluate the offered diversity gain of relay selection for different full-duplex cooperation schemes in the presence/absence of a direct source-destination link. When the adopted RSI link gain model is sublinear in the relay power, which agrees with recent research findings, we show that remarkable diversity gain can be recovered even in the presence of an interfering direct link. Second, we evaluate the end-to-end performance of FDRS with interference constraints due to the presence of a primary receiver. Finally, the presented exact theoretical findings are verified by numerical simulations.

  19. ON SECURE FULL DUPLEX COMMUNICATION IN MOBILE AD HOC NETWORK

    OpenAIRE

    S. C. Dutta; Sudha Singh; D. K. Singh

    2013-01-01

    This paper is to establish Ad Hoc network in mobile phones and start fully secured full duplex communication in any situation. This type of communication will be cost effective and it will be fastest way of communication in case of any server failure or server error.

  20. Micromechanics of base pair unzipping in the DNA duplex

    International Nuclear Information System (INIS)

    Volkov, Sergey N; Paramonova, Ekaterina V; Yakubovich, Alexander V; Solov’yov, Andrey V

    2012-01-01

    All-atom molecular dynamics (MD) simulations of DNA duplex unzipping in a water environment were performed. The investigated DNA double helix consists of a Drew-Dickerson dodecamer sequence and a hairpin (AAG) attached to the end of the double-helix chain. The considered system is used to examine the process of DNA strand separation under the action of an external force. This process occurs in vivo and now is being intensively investigated in experiments with single molecules. The DNA dodecamer duplex is consequently unzipped pair by pair by means of the steered MD. The unzipping trajectories turn out to be similar for the duplex parts with G⋅C content and rather distinct for the parts with A⋅T content. It is shown that during the unzipping each pair experiences two types of motion: relatively quick rotation together with all the duplex and slower motion in the frame of the unzipping fork. In the course of opening, the complementary pair passes through several distinct states: (i) the closed state in the double helix, (ii) the metastable preopened state in the unzipping fork and (iii) the unbound state. The performed simulations show that water molecules participate in the stabilization of the metastable states of the preopened base pairs in the DNA unzipping fork. (paper)

  1. Reliability Capacity of Half-Duplex Channels with Strict Deadlines

    DEFF Research Database (Denmark)

    Costa, Rui; Roetter, Daniel Enrique Lucani; Vinhoza, Tiago

    2015-01-01

    A fundamental characterization of a half-duplex wireless system with packet losses under traffic with hard deadlines is instrumental to understanding and developing efficient, coding aware policies for real-time applications. We set forth the concept of reliability capacity with a limited number ...

  2. Corrosion behavior of duplex and reference cladding in NPP Grohnde

    International Nuclear Information System (INIS)

    Besch, O.A.; Yagnik, S.K.; Eucken, C.M.; Bradley, E.R.

    1996-01-01

    The Nuclear Fuel Industry Research (NFIR) Group undertook a lead test assembly (LTA) program in NPP Grohnde PWR in Germany to assess the corrosion performance of duplex and reference cladding. Two identical 16 by 16 LTAs, each containing 32 peripheral test rods, completed four reactor cycles, reaching a peak rod burnup of 46 MWd/kgU. The results from poolside examinations performed at the end of each cycle, together with power histories and coolant chemistry, are reported. Five different cladding materials were characterized during fabrication. The corrosion performance of the cladding materials was tracked in long-term tests in high-pressure, high-temperature autoclaves. The relative ranking of corrosion behavior in such tests corresponded well with the in-reactor corrosion performance. The extent and distribution of hydriding in duplex and reference specimens during the autoclave testing has been characterized. The in-reactor corrosion data indicate that the low-tin Zircaloy-4 reference cladding, R2, had an improved corrosion resistance compared to high-tin Zircaloy-4 reference cladding, R1. Two types of duplex cladding, D1 (Zr-2.5% Nb) and D2 (Zr-0.4% Fe-0.5% Sn), showed an even further improvement in corrosion resistance compared to R2 cladding. The third duplex cladding, D3 (Zr-4 + 1.0% Nb), had significantly less corrosion resistance, which was inferior to R1. The in-reactor and out-reactor corrosion performances have been ranked

  3. Comprehensive Educational Assessment for the States: The Duplex Design.

    Science.gov (United States)

    Bock, R. Darrell; Mislevy, Robert

    State testing programs often attempt to provide annual information for use in student guidance and qualification, school and program evaluation, and broad policy decisions. With the development of a new type of assessment instrument, the "duplex design," the several functions of state testing programs can be served in a single test…

  4. Full-duplex wireless communications systems self-interference cancellation

    CERN Document Server

    Le-Ngoc, Tho

    2017-01-01

    This book introduces the development of self-interference (SI)-cancellation techniques for full-duplex wireless communication systems. The authors rely on estimation theory and signal processing to develop SI-cancellation algorithms by generating an estimate of the received SI and subtracting it from the received signal. The authors also cover two new SI-cancellation methods using the new concept of active signal injection (ASI) for full-duplex MIMO-OFDM systems. The ASI approach adds an appropriate cancelling signal to each transmitted signal such that the combined signals from transmit antennas attenuate the SI at the receive antennas. The authors illustrate that the SI-pre-cancelling signal does not affect the data-bearing signal. This book is for researchers and professionals working in wireless communications and engineers willing to understand the challenges of deploying full-duplex and practical solutions to implement a full-duplex system. Advanced-level students in electrical engineering and computer ...

  5. Perancangan dan Implementasi Duplexer Mikrostrip untuk Frekuensi LTE pada band ke-7

    Directory of Open Access Journals (Sweden)

    ENCENG SULAEMAN

    2013-07-01

    The necessary of mobile communication has increased in technology, now it released the new of technology is Long Term Evolution (LTE. Type of duplex is Frequency Division Duplex (FDD, designed a duplexer which it is capable for transmitting and receiving process at the same time with the different of frequency between uplink and downlink. Research of designed and implemented a duplexer using Hybrid Coupler and Bandstop filters based on Split Ring Resonators for the frequency band 7th on LTE technology at Base Transceiver Station (BTS. Duplexer is made by combining two coupler and two bandstop filter. The results of duplexer measurements, when Tx port transmit the signal to antenna port with attenuation at the downlink frequency center at 3.168 dB. Attenuation from antenna port to Rx port about 6 dB. Isolation between Tx port and Rx port about 15 dB. Keywords: Duplexer, Bandstop Filter, Split Ring Resonator, Hybrid Coupler, and Long Term Evolution.

  6. An evaluation of nuclear design characteristics of duplex burnable poison rods for extended cycle core

    International Nuclear Information System (INIS)

    Lee, D. J.; Kim, M. H.; Song, K. W.

    2003-01-01

    Nuclear design characteristics of duplex burnable poison rod were evaluated for three integral type burnable absorbers; Gadolinia, Erbia and IFBA. Inter-comparison was done for both 12 and 24 month cycle for Korean Standard Nuclear Plant. Fuel assemblies with duplex BP was designed to the equivalent assembly with 8 and 16 gadolinia BP 2 . Duplex BP is composed of inner region of natural U-Gd 2 O 3 , and outer shell of, UO 2 -Er2O 3 . In order to evaluate the duplex BP, assemblies with erbia and IFBA were compared with alternative options. A sensitivity studies were performed to the size of region, compositions and location of duplex BPs. It was shown that duplex BP gave favorable k-infinite curve to burnup, but IFBA provided the least residual reactivity penalty as EOC. Erbia was good for more negative MTCs. IFBA and erbia had better neutronic performance than gadolinia od duplex BP in the aspect of pin power peaking

  7. Renal pelvis urothelial carcinoma of the upper moiety in complete right renal duplex: a case report.

    Science.gov (United States)

    Zhang, Yiran; Yu, Quanfeng; Zhang, Zhihong; Liu, Ranlu; Xu, Yong

    2015-01-01

    Urothelial carcinoma (UC) originated from renal pelvis is the common tumor of the urinary system, however, neoplasia of the renal pelvis in duplex kidneys is extremely rare, especially in the complete renal and ureteral duplex cases. We present the first case of renal pelvis UC of the upper moiety in a complete right renal duplex. This male patient has bilateral complete renal and ureteral duplex. To the best of our knowledge, this is the first reported case of renal pelvis UC in a complete renal duplex system. After this experience we feel that the diagnosis of renal pelvis UC in duplex kidneys is not so easy, and once the diagnosis is determined, the whole renal duplex units and bladder cuff or ectopic orifice should be excised radically.

  8. Ultrasound imaging of the nose in septorhinoplasty patients.

    Science.gov (United States)

    Stenner, Markus; Rudack, Claudia

    2015-10-01

    Detailed preoperative planning based on available clinical information is an essential component of determining septorhinoplasty outcome. In addition to rhinoscopy and airway measurements, preoperative photographs are the only image modalities that are regularly used in septorhinoplasty patients and contribute to the preoperative planning of the surgery. The aim of this study was to evaluate the use of high-resolution ultrasonography in septorhinoplasty patients before surgery and during follow-up. We examined 35 patients before and after open septorhinoplasty using 12- and 15-MHz B-mode, linear array transducer ultrasound in noncontact mode. The patients presented with a variety of different functional and aesthetic problems, and all underwent septorhinoplasty for septal modification, and tip and dorsum refinement. The mean follow-up time for ultrasound after surgery was 4.5 weeks. Soft tissue, cartilaginous, and bony structures of the nose could be well-visualised. In the untreated nose, functional and aesthetic characteristics as well as preoperative anatomy relevant for the planning of the surgery could be documented. Surgical modifications of the treated nose postoperatively, that is, osteotomies, inserted spreader grafts, diced cartilage in fascia, and tip sutures could be visualized and followed. Ultrasonography of the nose with a high-frequency transducer may be a helpful tool during preoperative planning and postoperative follow-up in septorhinoplasty patients and might be a reasonable completion to the common photographic and functional diagnostic.

  9. Assessment of ureterovesical jet dynamics in obstructed ureter by urinary stone with color Doppler and duplex Doppler examinations.

    Science.gov (United States)

    Jandaghi, Ali Babaei; Falahatkar, Siavash; Alizadeh, Ahmad; Kanafi, Alireza Rajabzadeh; Pourghorban, Ramin; Shekarchi, Babak; Zirak, Amin Keshavarz; Esmaeili, Samaneh

    2013-04-01

    This study was designed to evaluate ureterovesical jet dynamics in obstructed ureter and to compare it with those of contralateral unobstructed side. Forty-six patients with diagnosis of ureteral stone, based on imaging findings in computed tomography were enrolled in this study. The gray-scale ultrasound exam from both kidneys and urinary bladder was performed. Then, ureterovesical jet characteristics including ureteral jet frequency, duration and peak velocity were assessed by color Doppler and duplex Doppler studies in both obstructed and unobstructed ureters by a radiologist, 15-30 min after oral hydration with 750-1,000 mL of water. When compared with contralateral normal side, the ureterovesical jet in obstructed ureter showed less frequency (0.59 vs. 3.04 jets/min; P < 0.05), shorter duration (1.24 vs. 5.26 s; P < 0.05) and lower peak velocity (5.41 vs. 32.09 cm/s; P < 0.05). The cut-off points of 1.5 jets/min, 2.5 s and 19.5 cm/s for difference of ureteral jet frequency, duration and peak velocity between obstructed and contralateral normal ureters yielded sensitivities of 97.8, 95.6 and 100 % and specificities of 87, 87.9 and 97.8 %, respectively for diagnosis of ureteral obstruction. Given the safety of Doppler study and significant differences in flow dynamics of obstructed versus unobstructed ureters, our findings demonstrated the utility of Doppler ultrasound examination as a useful adjunct to gray-scale ultrasound by improving the accuracy of ultrasound exam in diagnosis of ureteral obstruction.

  10. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... size, shape and consistency (whether the object is solid or filled with fluid). In medicine, ultrasound is ... ultrasound, measures the direction and speed of blood cells as they move through vessels. The movement of ...

  11. General Ultrasound Imaging

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    Full Text Available ... procedure? Ultrasound examinations can help to diagnose a variety of conditions and to assess organ damage following ... the Ultrasound-Guided Breast Biopsy page . diagnose a variety of heart conditions, including valve problems and congestive ...

  12. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... 3-D) ultrasound that formats the sound wave data into 3-D images. A Doppler ultrasound study ... at these links. About Us | Contact Us | FAQ | Privacy | Terms of Use | Links | Site Map Copyright © 2018 ...

  13. General Ultrasound Imaging

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    Full Text Available ... 3-D) ultrasound that formats the sound wave data into 3-D images. A Doppler ultrasound study ... to do the scanning. The transducer is a small hand-held device that resembles a microphone, attached ...

  14. General Ultrasound Imaging

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    Full Text Available ... in infections With knowledge about the speed and volume of blood flow gained from a Doppler ultrasound ... the body while other areas, especially air-filled lungs, are poorly suited for ultrasound. top of page ...

  15. General Ultrasound Imaging

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    Full Text Available ... flat sections of the body. Advancements in ultrasound technology include three-dimensional (3-D) ultrasound that formats ... color picture. It can also convert blood flow information into a distinctive sound that can be heard ...

  16. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... flat sections of the body. Advancements in ultrasound technology include three-dimensional (3-D) ultrasound that formats ... care physician, or to the physician or other healthcare provider who requested the exam. Usually, the referring ...

  17. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... flat sections of the body. Advancements in ultrasound technology include three-dimensional (3-D) ultrasound that formats ... at these links. About Us | Contact Us | FAQ | Privacy | Terms of Use | Links | Site Map Copyright © 2018 ...

  18. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... top of page What are the benefits vs. risks? Benefits Most ultrasound scanning is noninvasive (no needles ... procedures such as needle biopsies and fluid aspiration. Risks For standard diagnostic ultrasound , there are no known ...

  19. General Ultrasound Imaging

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    Full Text Available ... ultrasound. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... move through vessels. The movement of blood cells causes a change in pitch of the reflected sound ...

  20. General Ultrasound Imaging

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    Full Text Available ... ultrasound. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... requested the exam. Usually, the referring physician or health care provider will share the results with you. ...

  1. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... flat sections of the body. Advancements in ultrasound technology include three-dimensional (3-D) ultrasound that formats ... possible charges you will incur. Web page review process: This Web page is reviewed regularly by a ...

  2. General Ultrasound Imaging

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    Full Text Available ... need to be returned to the transducer for analysis. Ultrasound has difficulty penetrating bone and, therefore, can ... ultrasound procedure View full size with caption Pediatric Content Some imaging tests and treatments have special pediatric ...

  3. General Ultrasound Imaging

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    Full Text Available ... flat sections of the body. Advancements in ultrasound technology include three-dimensional (3-D) ultrasound that formats ... legs, neck and/or brain (in infants and children) or within various body organs such as the ...

  4. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... flat sections of the body. Advancements in ultrasound technology include three-dimensional (3-D) ultrasound that formats ... sonography is performed using the same transducer. Rarely, young children may need to be sedated in order ...

  5. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... image. Ultrasound examinations do not use ionizing radiation (as used in x-rays ), thus there is no ... structure and movement of the body's internal organs, as well as blood flowing through blood vessels. Ultrasound ...

  6. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... testing. image the breasts and guide biopsy of breast cancer ( see the Ultrasound-Guided Breast Biopsy page . diagnose ... Ultrasound is the preferred imaging modality for the diagnosis and monitoring of pregnant women and their unborn ...

  7. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... Ultrasound is the preferred imaging modality for the diagnosis and monitoring of pregnant women and their unborn ... needle biopsies and fluid aspiration. Risks For standard diagnostic ultrasound , there are no known harmful effects on ...

  8. General Ultrasound Imaging

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    Full Text Available ... More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z General Ultrasound Ultrasound ... computer or television monitor. The image is created based on the amplitude (loudness), frequency (pitch) and time ...

  9. General Ultrasound Imaging

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    Full Text Available ... ultrasound. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... more extensive exams may take up to an hour. When the examination is complete, you may be ...

  10. General Ultrasound Imaging

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    Full Text Available ... Imaging? Ultrasound waves are disrupted by air or gas; therefore ultrasound is not an ideal imaging technique ... with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy bear denotes ...

  11. General Ultrasound Imaging

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    Full Text Available ... may produce minimal discomfort. If a Doppler ultrasound study is performed, you may actually hear pulse-like sounds that change in pitch as the blood flow is monitored and measured. Most ultrasound examinations ...

  12. General Ultrasound Imaging

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    Full Text Available ... ultrasound. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media Angioplasty and ...

  13. General Ultrasound Imaging

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    Full Text Available ... ultrasound. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... about this beforehand and be made aware of food and drink restrictions that may be needed prior ...

  14. General Ultrasound Imaging

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    Full Text Available ... Ultrasound is safe, noninvasive, and does not use ionizing radiation. This procedure requires little to no special preparation. ... create an image. Ultrasound examinations do not use ionizing radiation (as used in x-rays ), thus there is ...

  15. General Ultrasound Imaging

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    Full Text Available ... flat sections of the body. Advancements in ultrasound technology include three-dimensional (3-D) ultrasound that formats ... American College of Radiology (ACR) and the Radiological Society of North America (RSNA), comprising physicians with expertise ...

  16. Medical Ultrasound Imaging.

    Science.gov (United States)

    Hughes, Stephen

    2001-01-01

    Explains the basic principles of ultrasound using everyday physics. Topics include the generation of ultrasound, basic interactions with material, and the measurement of blood flow using the Doppler effect. (Author/MM)

  17. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... ultrasound. top of page How does the procedure work? Ultrasound imaging is based on the same principles ... the transducer is pressed against the skin, it directs small pulses of inaudible, high-frequency sound waves ...

  18. Diagnostic imaging in liver transplantation. Preoperative evaluation and postoperative complications

    International Nuclear Information System (INIS)

    Schroeder, T.; Ruehm, S.G.

    2005-01-01

    Complimentary to orthotopic liver transplantation (OLT), living donor liver transplantation (LDLT) is increasingly considered a therapeutic option in the therapy of end-stage liver disease. Accurate pre- and postoperative imaging is crucial for the transplantation success and represents an established part of the current evaluation algorithms. This article summarizes the most important requirements and the current imaging standards. Preoperative imaging is important for exclusion of transplantation contraindications in the recipient and for reliable assessment of anatomical variants in the donor. The main purpose of postoperative imaging is the early detection and characterization of complications. In both instances, multislice CT currently represents the most versatile and reliable imaging modality, still superior to MRI. For postoperative follow-up, the imaging modality of first choice is still bedside ultrasound; however, unclear findings usually need to be further assessed by CT. (orig.) [de

  19. Full-Duplex Communications in Large-Scale Cellular Networks

    KAUST Repository

    AlAmmouri, Ahmad

    2016-04-01

    In-band full-duplex (FD) communications have been optimistically promoted to improve the spectrum utilization and efficiency. However, the penetration of FD communications to the cellular networks domain is challenging due to the imposed uplink/downlink interference. This thesis presents a tractable framework, based on stochastic geometry, to study FD communications in multi-tier cellular networks. Particularly, we assess the FD communications effect on the network performance and quantify the associated gains. The study proves the vulnerability of the uplink to the downlink interference and shows that the improved FD rate gains harvested in the downlink (up to 97%) comes at the expense of a significant degradation in the uplink rate (up to 94%). Therefore, we propose a novel fine-grained duplexing scheme, denoted as α-duplex scheme, which allows a partial overlap between the uplink and the downlink frequency bands. We derive the required conditions to harvest rate gains from the α-duplex scheme and show its superiority to both the FD and half-duplex (HD) schemes. In particular, we show that the α-duplex scheme provides a simultaneous improvement of 28% for the downlink rate and 56% for the uplink rate. We also show that the amount of the overlap can be optimized based on the network design objective. Moreover, backward compatibility is an essential ingredient for the success of new technologies. In the context of in-band FD communication, FD base stations (BSs) should support HD users\\' equipment (UEs) without sacrificing the foreseen FD gains. The results show that FD-UEs are not necessarily required to harvest rate gains from FD-BSs. In particular, the results show that adding FD-UEs to FD-BSs offers a maximum of 5% rate gain over FD-BSs and HD-UEs case, which is a marginal gain compared to the burden required to implement FD transceivers at the UEs\\' side. To this end, we shed light on practical scenarios where HD-UEs operation with FD-BSs outperforms the

  20. Downlink Error Rates of Half-duplex Users in Full-duplex Networks over a Laplacian Inter-User Interference Limited and EGK fading

    KAUST Repository

    Soury, Hamza; Elsawy, Hesham; Alouini, Mohamed-Slim

    2017-01-01

    This paper develops a mathematical framework to study downlink error rates and throughput for half-duplex (HD) terminals served by a full-duplex (FD) base station (BS). The developed model is used to motivate long term pairing for users that have

  1. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... transducer sends out high-frequency sound waves (that the human ear cannot hear) into the body and then ... ultrasound , there are no known harmful effects on humans. top of page What are the limitations of General Ultrasound Imaging? Ultrasound waves are ...

  2. Clinical diagnostic ultrasound

    International Nuclear Information System (INIS)

    Barnett, E.; Morley, P.

    1986-01-01

    This textbook on diagnostic ultrasound covers the main systems, with emphasis being placed on the clinical application of diagnostic ultrasound in everyday practice. It provides not only a textbook for postgraduates (particularly FRCR candidates), but also a reference work for practitioners of clinical ultrasound and clinicians generally

  3. Preoperative fasting time in children.

    LENUS (Irish Health Repository)

    Adeel, S

    2012-02-01

    The aim of preoperative fasting is to prevent regurgitation and pulmonary aspiration while limiting potential problems of thirst, dehydration and hypoglycaemia. The American Society of Anaesthesiologists (ASA) has suggested guidelines for preoperative fasting for children undergoing elective surgery. We did a postal survey to determine the current practice regarding these guidelines amongst all specialist registrars in anaesthesia in Ireland. A questionnaire was sent to all specialist registrars in anaesthesia (90 in total), 60 (67%) were returned and analysed. The question asked was how long children should be kept fasting before elective surgery. The results of our survey suggest that most of the respondents are following the ASA guidelines for clear fluids and solids however there were differing opinion regarding the duration of fasting for formula milk and breast milk. In conclusion, we would recommend greater awareness and collaboration between anaesthetists, nurses and surgeons to ensure that fasting instructions are consistent with the ASA guidelines and that patient and their parents understand these directives as well.

  4. Preoperative irradiation of hypernephroid carcinoma

    International Nuclear Information System (INIS)

    Akbar, D.

    1982-01-01

    Since 1969, preoperative irradiation of hypernephiroid carcinoma has been a routine measure at the Steglitz medical clinic: It consists in the application of a focal dose of 30 Gy, fractionated into doses of 2.5 Gy, as Betatron pendulum irradiation (42 MeV photons) covering the para-aortic lymph nodes. After a treatment-free interval of 3 weeks, radical nephrectomy is carried through. Of 178 patients, 47 were in tumor stage I, 15 in stage II, 83 in stage III and 33 in stage IV. In 99 patients the treatment dated back longer than 5 years; the survival rate was 52%. 67% of the patients had survived longer than 3 years. Operation lethality was 3%. The preoperative irradiation pursues the following aims: 1. Devitalization of potentially proliferating cells in the tumor periphery, and thus prevention of displaced tumor cells growing on and postoperative local recidivations; 2. Shrinking of the tumor, facilitating the surgical intervention. In a third of the cases a measurable alteration of the tumor was confirmed by X-ray. The low operation lethality of 3% is attributed to this. (orig./MG) [de

  5. Preoperative embolization of gigantic meningioma

    International Nuclear Information System (INIS)

    Wang Hongsheng; Chen Huaqun; Dong Congsong; Li Wenhui; Dai Zhenyu; Chen Guozhi

    2006-01-01

    Objective: To evaluate the clinical efficacy of preoperative embolization in treatment of patients with gigantic meningioma. Methods: Fourteen cases of gigantic meningioma diameter from 6 to 11 cm were measured by CT and MRI scan. DSA manifested that they are vascularizd meningioma and showed the mainly feeding arteries. We used getation sponge to superselectively embilized the feeding arteries. All tumors were performed surgical excision 3-7 days after the embolization. Results: DSA showed the blood supplies in the tumors in 9 cases were completely blocked, and that in 5 cases were dramatically eliminated. All patients were operated 3-7 days after the embolization. During the operations the bleeding were dramatically decreased and the operation time was shortened compared with those in unembolized cases. It helps us remove the tumors easy and quickly from the attachments. No complication occurred during and after the operations. Conclusion: Preoperative embolization of gigantic meningioma is a useful and relatively safe method in helping surgicaly and completely excised of tumor with significant reduction of blood loss and operation time. (authors)

  6. Preoperative embolization of facial angiomas

    International Nuclear Information System (INIS)

    Causmano, F.; Bruschi, G.; De Donatis, M.; Piazza, P.; Bassi, P.

    1988-01-01

    Preoperative embolization was performed on 27 patients with facial angiomas supplied by the external carotid branches. Sixteen were males and 11 females; 13 of these angiomas were high-flow arterio-venous (A-V), 14 were low-flow capillary malformations. Fourteen patients underwent surgical removal after preoperative embolization; in this group embolization was carried out with Spongel in 3 cases and with Lyodura in 11 cases. In 12 of these patients the last angiographic examination was performed 3-6 years later: angiography evidenced no recurrence in 8 cases (67%), while in 3 cases (25%) there was capillary residual angioma of negligible size. Treatment was unsuccessful in one patient only, due to the large recurrent A-V angioma. Thirteen patients underwent embolization only, which was carried out with Lyodura in 10 cases, and with Ivalon in 3 cases. On 12 of these patients the last angiographic study was performed 2-14 months later: there was recurrent A-V angioma in 5 patients (42%), who underwent a subsequent embolization; angiography evidenced no recurrence in the other 7 patients (58%). In both series, the best results were obtained in the patients with low-flow capillary angiomas. Embolization and subsequent surgical removal are the treatment of choice for facial angiomas; embolization alone is useful in the management of surgically inacessible vascular malformations, and it can be the only treatment in patients with small low-flow angiomas when distal occlusion of the feeding vessel with Lyodura or Ivalon particles is performed

  7. Tensile properties of duplex UNS S32205 and lean duplex UNS S32304 steels and the influence of short duration 475 ºC aging

    Directory of Open Access Journals (Sweden)

    Sérgio Souto Maior Tavares

    2012-12-01

    Full Text Available Duplex stainless steels are high strength and corrosion resistant steels extensively used in the petrochemical and chemical industries. The aging at 475 ºC for long periods of time provokes embrittlement and deterioration of corrosion resistance. However, short duration aging at 475 ºC may be used as heat treatment to improve mechanical resistance with small decrease in the other properties. In this work the flow stress curves of lean duplex UNS S32304 and duplex UNS S32205 steels were modeled with Hollomon's equation and work hardening exponents (n were determined. The analyses were conducted in specimens annealed and heat treated at 475 ºC for short periods of time. The aging at 475 ºC for 4 hours, 8 hours and 12 hours promoted significant hardening with small decrease of ductility. The work hardening exponents of both steels were compared, being higher in the duplex steel than in the lean duplex grade.

  8. Mechanical Deformation Behavior of Lean Duplex 329LA Steel

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Byung-Jun [Research Institute of Industrial Science and Technology, Pohang (Korea, Republic of); Choi, Jeom-Yong [POSCO Technical Research Lab., Pohang (Korea, Republic of); Park, Kyung-Tae [Hanvat National University, Daejeon (Korea, Republic of); Lee, Ho Seong [Kyungpook National University, Daegu (Korea, Republic of)

    2015-09-15

    The tensile response of Lean Duplex 329LA stainless steel was investigated over various strain rates. It was observed that the mechanical response, including in particular the total elongation of the tested alloy, was strongly affected by the strain rate. As the strain rate decreased from 10-1 s-1 to 10-4 s-1, the elongation increased. As the strain rate increased, the deformation mode in an austenite phase was dominated by dislocation glide, resulting in deterioration of the elongation. The substructure of the ferritic phase showed a dislocation cell structure, independent of the applied strain rate. The optimum mechanical properties of lean duplex stainless steel thus can be obtained by controlling the deformation mode in the austenitic phase.

  9. Mechanical Deformation Behavior of Lean Duplex 329LA Steel

    International Nuclear Information System (INIS)

    Yoon, Byung-Jun; Choi, Jeom-Yong; Park, Kyung-Tae; Lee, Ho Seong

    2015-01-01

    The tensile response of Lean Duplex 329LA stainless steel was investigated over various strain rates. It was observed that the mechanical response, including in particular the total elongation of the tested alloy, was strongly affected by the strain rate. As the strain rate decreased from 10-1 s-1 to 10-4 s-1, the elongation increased. As the strain rate increased, the deformation mode in an austenite phase was dominated by dislocation glide, resulting in deterioration of the elongation. The substructure of the ferritic phase showed a dislocation cell structure, independent of the applied strain rate. The optimum mechanical properties of lean duplex stainless steel thus can be obtained by controlling the deformation mode in the austenitic phase.

  10. Duplex-tube sodium-indication steam generator

    International Nuclear Information System (INIS)

    Matal, O.; Martoch, J.

    1984-01-01

    The steam generator with duplex tubes and sodium indication is connected to the main sodium input and output via the inlet and outlet chambers and has indication spaces connected to the interspaces of the duplex tubes. The first indication space is linked with the auxiliary inlet pipe to the inlet chamber and the second indication space is connected with the auxiliary pipe to the outlet chamber. Mounted to the auxiliary inlet pipe is at least one closure, i.e., a valve or electromagnetic stop. Mounted on the auxiliary outlet pipe is an indication sensor, e.g., a sodium flow sensor. At least one indication space is provided with an alarm sensor, e.g., a thermocouple, a pressure gauge and one sensor to monitor the hydrogen content of sodium. (J.P.)

  11. Comments on process of duplex coatings on aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    Samir H.A.; QIAN Han-cheng(钱翰城); XIA Bo-cai(夏伯才); WU Shi-ming(吴仕明)

    2004-01-01

    Despite the great achievements made in improvement of wear resistance properties of aluminum alloys,their applications in heavy surface load-bearing are limited. Single coating is insufficient to produce the desired combination of surface properties. These problems can be solved through the duplex coatings. The aim of the present study is to overview the research advances on processes of duplex coatings on aluminum alloys combined with micro plasma oxidation process and with other modern processes such as physical vapour deposition and plasma assisted chemical vapour deposition and also to evaluate the performance of micro plasma oxidation coatings in improving the load-bearing, friction and wear resistance properties of aluminum alloys in comparison with other coatings. Wherein, a more detailed presentation of the processes and their performances and disadvantages are given as well.

  12. Weld oxide formation on lean duplex stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Westin, E.M. [Outokumpu Stainless, Avesta Research Centre, P.O. Box 74, SE-774 22 Avesta (Sweden)], E-mail: elin.westin@outokumpu.com; Olsson, C.-O.A. [Outokumpu Stainless, Avesta Research Centre, P.O. Box 74, SE-774 22 Avesta (Sweden); Hertzman, S. [Outokumpu Stainless Research Foundation, Brinellvaegen 23, SE-100 44 Stockholm (Sweden)

    2008-09-15

    Weld oxides have a strong influence on corrosion resistance, but have hitherto only been studied to a limited extent for duplex stainless steels. X-ray photoelectron spectroscopy (XPS) has here been used to study heat tint formed on gas tungsten arc (GTA) welds on the commercial duplex grades LDX 2101 (EN 1.4162/UNS S32101) and 2304 (EN 1.4362/UNS S32304) welded with and without nitrogen additions to the shielding gas. The process of heat tint formation is discussed in terms of transport phenomena to explain the effect of atmosphere, temperature and composition. The oxides formed were found to be enriched in manganese and corrosion testing shows that nitrogen has a strong influence on the weld oxide. A mechanism is proposed including evaporation from the weld pool and subsequent redeposition.

  13. Listen and talk full-duplex cognitive radio networks

    CERN Document Server

    Liao, Yun; Han, Zhu

    2016-01-01

    This brief focuses on the use of full-duplex radio in cognitive radio networks, presenting a novel spectrum sharing protocol that allows the secondary users to simultaneously sense and access the vacant spectrum. This protocol, called “Listen-and-talk” (LAT), is evaluated by both mathematical analysis and computer simulations in comparison with other existing protocols, including the listen-before-talk protocol. In addition to LAT-based signal processing and resource allocation, the brief discusses techniques such as spectrum sensing and dynamic spectrum access. The brief proposes LAT as a suitable access scheme for cognitive radio networks, which can support the quality-of-service requirements of these high priority applications. Fundamental theories and key techniques of cognitive radio networks are also covered. Listen and Talk: Full-duplex Cognitive Radio Networks is designed for researchers, developers, and professionals involved in cognitive radio networks. Advanced-level students studying signal pr...

  14. Standard test methods for characterizing duplex grain sizes

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2002-01-01

    1.1 These test methods provide simple guidelines for deciding whether a duplex grain size exists. The test methods separate duplex grain sizes into one of two distinct classes, then into specific types within those classes, and provide systems for grain size characterization of each type. 1.2 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns associated with its use. It is the responsibility of the user of this standard to consult appropriate safety and health practices and determine the applicability of regulatory limitations prior to its use.

  15. Weld oxide formation on lean duplex stainless steel

    International Nuclear Information System (INIS)

    Westin, E.M.; Olsson, C.-O.A.; Hertzman, S.

    2008-01-01

    Weld oxides have a strong influence on corrosion resistance, but have hitherto only been studied to a limited extent for duplex stainless steels. X-ray photoelectron spectroscopy (XPS) has here been used to study heat tint formed on gas tungsten arc (GTA) welds on the commercial duplex grades LDX 2101 (EN 1.4162/UNS S32101) and 2304 (EN 1.4362/UNS S32304) welded with and without nitrogen additions to the shielding gas. The process of heat tint formation is discussed in terms of transport phenomena to explain the effect of atmosphere, temperature and composition. The oxides formed were found to be enriched in manganese and corrosion testing shows that nitrogen has a strong influence on the weld oxide. A mechanism is proposed including evaporation from the weld pool and subsequent redeposition

  16. Preoperative patient education: evaluating postoperative patient outcomes.

    Science.gov (United States)

    Meeker, B J

    1994-04-01

    Preoperative teaching is an important part of patient care and can prevent complications, as well as promote patient fulfillment during hospitalization. A study was conducted at Alton Ochsner Medical Foundation in New Orleans, LA, in 1989, to determine the impact of a preoperative teaching program on the incidence of postoperative atelectasis and patient satisfaction. Results showed no significant difference of postoperative complications and patient gratification after participating in a structured preoperative teaching program. As part of this study, it was identified that a patient evaluation tool for a preoperative teaching class needed to be developed. The phases of this process are explained in the following article.

  17. Internal stresses in an austeno-ferritic duplex stainless steel

    International Nuclear Information System (INIS)

    Verhaeghe, B.; Brechet, Y.; Louchet, F.; Massoud, J.P.; Touzeau, D.

    1996-04-01

    Austeno-ferritic duplex steels possess microstructures containing comparable volume fractions of hard and soft phases which are bi-percolated. They are therefore liable to develop large internal stresses during straining. The evolution and the relaxation of these stresses and the occurrence of damage are characterized using Bauschinger tests. Thermally aged and non-aged material behaviour are compared. Plastic flow in the hard phase is shown to be significantly efficient in releasing these internal stresses. (authors). 15 refs., 8 figs

  18. Investigation of hot cracking resistance of 2205 duplex steel

    Energy Technology Data Exchange (ETDEWEB)

    Adamiec, J; Scibisz, B, E-mail: janusz.adamiec@polsl.pl [Silesian University of Technology, Faculty of Materials Science and Metallurgy, ul. Krasinskiego 8, PL-40019 Katowice (Poland)

    2010-02-15

    Austenitic duplex steel of the brand 2205 according to Avesta Sheffield is used for welded constructions (pipelines, tanks) in the petrol industry, chemical industry and food industry. It is important to know the range of high-temperature brittleness in designing welding technology for constructions made of this steel type. There is no data in literature concerning this issue. High-temperature brittleness tests using the simulator of heat flow device Gleeble 3800 were performed. The tests results allowed the evaluation of the characteristic temperatures in the brittleness temperature range during the joining of duplex steels, specifically the nil-strength temperature (NST) and nil-ductility temperatures (NDT) during heating, the strength and ductility recovery temperatures (DRT) during cooling, the R{sub f}parameter (R{sub f} = (T{sub liquidus} - NDT)/NDT) describing the duplex steel inclination for hot cracking, and the brittleness temperature range (BTR). It has been stated that, for the examined steel, this range is wide and amounts to ca. 90 deg. C. The joining of duplex steels with the help of welding techniques creates a significant risk of hot cracks. After analysis of the DTA curves a liquidus temperature of T{sub L} = 1465 deg. C and a solidus temperature of T{sub S} = 1454 deg. C were observed. For NST a mean value was assumed, in which the cracks appeared for six samples; the temperature was 1381 deg. C. As the value of the NDT temperature 1367 deg. C was applied while for DRT the assumed temperature was 1375 deg. C. The microstructure of the fractures was observed using a Hitachi S-3400N scanning electron microscope (SEM). The analyses of the chemical composition were performed using an energy-dispersive X-ray spectrometer (EDS), Noran System Six of Thermo Fisher Scientific. Essential differences of fracture morphology type over the brittle temperature range were observed and described.

  19. Investigation of hot cracking resistance of 2205 duplex steel

    Science.gov (United States)

    Adamiec, J.; Ścibisz, B.

    2010-02-01

    Austenitic duplex steel of the brand 2205 according to Avesta Sheffield is used for welded constructions (pipelines, tanks) in the petrol industry, chemical industry and food industry. It is important to know the range of high-temperature brittleness in designing welding technology for constructions made of this steel type. There is no data in literature concerning this issue. High-temperature brittleness tests using the simulator of heat flow device Gleeble 3800 were performed. The tests results allowed the evaluation of the characteristic temperatures in the brittleness temperature range during the joining of duplex steels, specifically the nil-strength temperature (NST) and nil-ductility temperatures (NDT) during heating, the strength and ductility recovery temperatures (DRT) during cooling, the Rfparameter (Rf = (Tliquidus - NDT)/NDT) describing the duplex steel inclination for hot cracking, and the brittleness temperature range (BTR). It has been stated that, for the examined steel, this range is wide and amounts to ca. 90 °C. The joining of duplex steels with the help of welding techniques creates a significant risk of hot cracks. After analysis of the DTA curves a liquidus temperature of TL = 1465 °C and a solidus temperature of TS = 1454 °C were observed. For NST a mean value was assumed, in which the cracks appeared for six samples; the temperature was 1381 °C. As the value of the NDT temperature 1367 °C was applied while for DRT the assumed temperature was 1375 °C. The microstructure of the fractures was observed using a Hitachi S-3400N scanning electron microscope (SEM). The analyses of the chemical composition were performed using an energy-dispersive X-ray spectrometer (EDS), Noran System Six of Thermo Fisher Scientific. Essential differences of fracture morphology type over the brittle temperature range were observed and described.

  20. Investigation of hot cracking resistance of 2205 duplex steel

    International Nuclear Information System (INIS)

    Adamiec, J; Scibisz, B

    2010-01-01

    Austenitic duplex steel of the brand 2205 according to Avesta Sheffield is used for welded constructions (pipelines, tanks) in the petrol industry, chemical industry and food industry. It is important to know the range of high-temperature brittleness in designing welding technology for constructions made of this steel type. There is no data in literature concerning this issue. High-temperature brittleness tests using the simulator of heat flow device Gleeble 3800 were performed. The tests results allowed the evaluation of the characteristic temperatures in the brittleness temperature range during the joining of duplex steels, specifically the nil-strength temperature (NST) and nil-ductility temperatures (NDT) during heating, the strength and ductility recovery temperatures (DRT) during cooling, the R f parameter (R f = (T liquidus - NDT)/NDT) describing the duplex steel inclination for hot cracking, and the brittleness temperature range (BTR). It has been stated that, for the examined steel, this range is wide and amounts to ca. 90 deg. C. The joining of duplex steels with the help of welding techniques creates a significant risk of hot cracks. After analysis of the DTA curves a liquidus temperature of T L = 1465 deg. C and a solidus temperature of T S = 1454 deg. C were observed. For NST a mean value was assumed, in which the cracks appeared for six samples; the temperature was 1381 deg. C. As the value of the NDT temperature 1367 deg. C was applied while for DRT the assumed temperature was 1375 deg. C. The microstructure of the fractures was observed using a Hitachi S-3400N scanning electron microscope (SEM). The analyses of the chemical composition were performed using an energy-dispersive X-ray spectrometer (EDS), Noran System Six of Thermo Fisher Scientific. Essential differences of fracture morphology type over the brittle temperature range were observed and described.

  1. On full duplex Gaussian relay channels with self-interference

    KAUST Repository

    Behboodi, Arash

    2016-08-15

    Self interference (SI) in full duplex (FD) systems is the interference caused by the transmission stream on the reception stream. Being one of the main restrictive factors for performance of practical full duplex systems, however, not too much is known about its effect on the fundamental limits of relaying systems. In this work, we consider the full duplex three-node relay channel with SI where SI is modeled as an additive Gaussian noise whose variance is dependent on instantaneous input power. The classical achievable rates and upper bounds for the single three-node relay channel no longer apply due to the structure of SI. Achievable rates for Decode-and-Forward (DF) and Compress-and-Forward (CF) and upper bounds on the capacity are derived assuming Gaussian inputs and SI. The deterministic model is also introduced and its capacity is characterized. The optimal joint source-relay distributions is discussed. Numerical results are provided comparing the achievable rates and upper bound. © 2016 IEEE.

  2. Duplex Schemes in Multiple Antenna Two-Hop Relaying

    Directory of Open Access Journals (Sweden)

    Anja Klein

    2008-04-01

    Full Text Available A novel scheme for two-hop relaying defined as space division duplex (SDD relaying is proposed. In SDD relaying, multiple antenna beamforming techniques are applied at the intermediate relay station (RS in order to separate downlink and uplink signals of a bi-directional two-hop communication between two nodes, namely, S1 and S2. For conventional amplify-and-forward two-hop relaying, there appears a loss in spectral efficiency due to the fact that the RS cannot receive and transmit simultaneously on the same channel resource. In SDD relaying, this loss in spectral efficiency is circumvented by giving up the strict separation of downlink and uplink signals by either time division duplex or frequency division duplex. Two novel concepts for the derivation of the linear beamforming filters at the RS are proposed; they can be designed either by a three-step or a one-step concept. In SDD relaying, receive signals at S1 are interfered by transmit signals of S1, and receive signals at S2 are interfered by transmit signals of S2. An efficient method in order to combat this kind of interference is proposed in this paper. Furthermore, it is shown how the overall spectral efficiency of SDD relaying can be improved if the channels from S1 and S2 to the RS have different qualities.

  3. Duplex geometry: an example from the Moine Thrust Belt

    Science.gov (United States)

    Bowler, S.

    1987-04-01

    The geometry and microstructure of a small duplex formed in one bed from the Moine Thrust Belt of northwest Scotland is reported. The structure is seen in oblique section, within the Cambrian Pipe-rock, in an area of low strain. A range of movement direction indicators are present in the structure. An early grain shape fabric developed close to the roof thrust is taken as the best estimate of the overall movement direction towards 287°. Slickensides in the gouge developed on movement planes within the duplex show varied orientations on a given plane, and are not considered useful indicators of thrust transport direction. Branch lines exposed converge and diverge, suggesting little lateral continuity of the exposed structure. The microstructures present within the structure indicate an increase in localised deformation, and in cataclastic behavior as the duplex evolved. Early layer parallel shear is ubiquitous, giving rise to an elongate grain shape fabric close to bedding surfaces. In early formed horses, a layer-parallel, oblate grain shape fabric, which shows localised slip zones, is overprinted by gouge formation. Later formed horses show only fracturing and gouge development. This sequence is attributed to stick-slip behavior in the propagation or displacement of the original fault, now the floor thrust.

  4. Microstructures and mechanical properties of duplex low carbon steel

    Science.gov (United States)

    Alfirano; Eben, U. S.; Hidayat, M.

    2018-04-01

    The microstructures behavior of duplex cold-rolled low carbon steel for automotive applications has been investigated. Intercritical annealing treatment is commonly used to develop a duplex low carbon steel containing ferrite and martensite. To get a duplex phase ferrite and martensite, the specimens were heated at inter-critical annealing temperature of 775°C - 825°C, for heating time up to 20 minutes, followed by water-quenched. The hardness of specimens was studied. The optical microscopy was used to analyze the microstructures. The optimal annealing conditions (martensite volume fraction approaching 20%) at 775°C with a heating time of 10 minutes was achieved. The highest hardness value was obtained in cold-rolled specimens of 41% in size reduction for intercritical annealing temperature of 825°C. In this condition, the hardness value was 373 HVN. The correlation between intercritical annealing temperature and time can be expressed in the transformation kinetics as fγ/fe = 1-exp(-Ktn) wherein K and n are grain growth rate constant and Avrami’s exponent, respectively. From experiment, the value of K = 0.15 and n = 0.461. Using the relationship between temperatures and heating time, activation energy (Q) can be calculated that is 267 kJ/mol.

  5. Development and test evaluation of duplex steam reformer tube

    International Nuclear Information System (INIS)

    Allen, D.C.; Meyer, D.J.; Pflasterer, G.R.

    1980-01-01

    For HTR applications involving a steam reformer (SR), it is uncertain whether an intermediate heat exchanger (IHX) is required. There are several system configurations that could be developed for the application of nuclear heat using the steam reformer reaction. The considerations (advantages vs. disadvantages) for each of the system configurations are summarized. The approach that technically and economically appears to be the most attractive, in studies conducted by General Electric, combines the SR process heat exchanger and the IHX in a single component using a duplex tube. A central question concerning the duplex tube concept is whether the design would provide adequate leak monitoring capability and significant reduction in tritium and hydrogen diffusion, while introducing only a small increase in overall temperature difference from the helium to the process gas. A cooperative GE-KFA effort was undertaken to develop, fabricate, test, and evaluate a duplex steam reformer tube. GE was responsible for the development and fabrication of the tube, and KFA was responsible for testing the tube in the EVA I facility at Juelich. Both GE and KFA are evaluating the thermochemical and metallurgical test data. Actual fabrication of the tube was performed by Foster-Wheeler in accordance with the GE design. This paper reviews the highlights of the fabrication development and preliminary evaluation of the test data

  6. Interventions for preoperative smoking cessation

    DEFF Research Database (Denmark)

    Thomsen, Thordis; Villebro, Nete; Møller, Ann Merete

    2010-01-01

    a smoking cessation intervention, and measured preoperative and long-term abstinence from smoking and/or the incidence of postoperative complications. Data collection and analysis The authors independently assessed studies to determine eligibility. Results were discussed between the authors. Main results...... Eight trials enrolling a total of 1156 people met the inclusion criteria. One of these did not report cessation as an outcome. Two trials initiated multisession face to face counselling at least 6 weeks before surgery whilst six used a brief intervention. Nicotine replacement therapy (NRT) was offered......; pooled RR 10.76 (95% confidence interval (CI) 4.55 to 25.46, two trials) and RR 1.41 (95% CI 1.22 to 1.63, five trials) respectively. Four trials evaluating the effect on long-term smoking cessation found a significant effect; pooled RR 1.61 (95% CI 1.12 to 2.33). However, when pooling intensive...

  7. Qualitative comparison of duplex Stirling and absorption refrigerators in domestic applications

    Energy Technology Data Exchange (ETDEWEB)

    Shao, H. [Global Cooling BV, Zutphen (Netherlands)

    2000-07-01

    A qualitative comparison has been carried out between the duplex Stirling and the absorption refrigerator for domestic applications. The duplex Stirling has many advantages over the absorption refrigerator on efficiency, modulation, suitability, operating costs, pollution reduction. Based on the state of the art of free-piston gas-bearing and linear-motor Stirling engines and coolers, it appears technically and economically feasible to develop the duplex Stirling to compete with the absorption refrigerator for heat-driven domestic refrigeration. (orig.)

  8. Characterization of duplex stainless steel weld metals obtained by hybrid plasma-gas metal arc welding

    OpenAIRE

    Yurtisik,Koray; Tirkes,Suha; Dykhno,Igor; Gur,C. Hakan; Gurbuz,Riza

    2013-01-01

    Despite its high efficiency, autogenous keyhole welding is not well-accepted for duplex stainless steels because it causes excessive ferrite in as-welded duplex microstructure, which leads to a degradation in toughness and corrosion properties of the material. Combining the deep penetration characteristics of plasma arc welding in keyhole mode and metal deposition capability of gas metal arc welding, hybrid plasma - gas metal arc welding process has considered for providing a proper duplex mi...

  9. Skull registration for prone patient position using tracked ultrasound

    Science.gov (United States)

    Underwood, Grace; Ungi, Tamas; Baum, Zachary; Lasso, Andras; Kronreif, Gernot; Fichtinger, Gabor

    2017-03-01

    PURPOSE: Tracked navigation has become prevalent in neurosurgery. Problems with registration of a patient and a preoperative image arise when the patient is in a prone position. Surfaces accessible to optical tracking on the back of the head are unreliable for registration. We investigated the accuracy of surface-based registration using points accessible through tracked ultrasound. Using ultrasound allows access to bone surfaces that are not available through optical tracking. Tracked ultrasound could eliminate the need to work (i) under the table for registration and (ii) adjust the tracker between surgery and registration. In addition, tracked ultrasound could provide a non-invasive method in comparison to an alternative method of registration involving screw implantation. METHODS: A phantom study was performed to test the feasibility of tracked ultrasound for registration. An initial registration was performed to partially align the pre-operative computer tomography data and skull phantom. The initial registration was performed by an anatomical landmark registration. Surface points accessible by tracked ultrasound were collected and used to perform an Iterative Closest Point Algorithm. RESULTS: When the surface registration was compared to a ground truth landmark registration, the average TRE was found to be 1.6+/-0.1mm and the average distance of points off the skull surface was 0.6+/-0.1mm. CONCLUSION: The use of tracked ultrasound is feasible for registration of patients in prone position and eliminates the need to perform registration under the table. The translational component of error found was minimal. Therefore, the amount of TRE in registration is due to a rotational component of error.

  10. EFFECT OF INTERMETALLIC PHASES ON CORROSION BEHAVIOR AND MECHANICAL PROPERTIES OF DUPLEX STAINLESS STEEL AND SUPER-DUPLEX STAINLESS STEEL

    Directory of Open Access Journals (Sweden)

    Prabhu Paulraj

    2015-08-01

    Full Text Available Duplex Stainless Steels (DSS and Super Duplex Stainless Steel (SDSS have excellent integration of mechanical and corrosion properties. However, the formation of intermetallic phases is a major problem in their usage. The mechanical and corrosion properties are deteriorated due to the presence of intermetallic phases. These phases are induced during welding, prolonged exposure to high temperatures, and improper heat treatments. The main emphasis of this review article is on intermetallic phases and their effects on corrosion and mechanical properties. First the effect of various alloying elements on DSS and SDSS has been discussed followed by formation of various intermetallic phases. The intermetallic phases affect impact toughness and corrosion resistance significantly. Their deleterious effect on weldments has also been reviewed.

  11. Validation of subclavian duplex velocity criteria to grade severity of subclavian artery stenosis.

    Science.gov (United States)

    Mousa, Albeir Y; Morkous, Ramez; Broce, Mike; Yacoub, Michael; Sticco, Andrew; Viradia, Ravi; Bates, Mark C; AbuRahma, Ali F

    2017-06-01

    Validation of subclavian duplex ultrasound velocity criteria (SDUS VC) to grade the severity of subclavian artery stenosis has not been established or systematically studied. Currently, there is a paucity of published literature and lack of practitioner consensus for how subclavian duplex velocity findings should be interpreted in patients with subclavian artery stenosis. The objective of the present study was to validate SDUS measurements using subclavian conventional or computed tomography angiogram (subclavian angiogram [SA])-derived measurements. Secondary objectives included measuring the correlation between SDUS peak systolic velocities and SA measurements, and to determine the optimal cutoff value for predicting significant stenosis (>70%). This is a retrospective review of all patients with suspected subclavian artery stenosis and a convenience sample of carotid artery patients who underwent SDUS and SA from May 1999 to July 2013. SA reference vessel and intralesion minimal lumen diameters were measured and compared with SDUS velocities obtained within 3 months of the imaging study. Percent stenosis was calculated using the North American Symptomatic Carotid Endarterectomy Trial method for detecting stenosis in a sufficiently large cohort. Receiver operating characteristic curves was generated for SDUS VC to predict >70% stenosis. Velocity cutoff points were determined with equal weighting of sensitivity and specificity. We examined 268 arteries for 177 patients. The majority of the arteries were for female patients (52.5%) with a mean age of 66.7 ± 11.1 years. Twenty-three arteries had retrograde vertebral artery flow and excluded from further analysis. For the remaining 245 arteries, the average peak systolic velocity was 212.6 ± 110.7 cm/s, with a range of 45-626 cm/s. Average stenosis was 25.8% ± 28.2%, with a range of 0% to 100%. Following receiver operating characteristic analysis, we found a cutoff value of >240 cm/s to be most predictive

  12. Endovascular aneurysm repair: state-of-art imaging techniques for preoperative planning and surveillance

    DEFF Research Database (Denmark)

    Truijers, M; Resch, T; Van Den Berg, J C

    2009-01-01

    and dual-source CT could reduce radiation dose and obviate the need for nephrotoxic contrast. Up-to-date knowledge of non-invasive vascular imaging and image processing is crucial for EVAR planning and is essential for the development of follow-up programs involving reduced risk of harmful side effects....... dynamic CTA and MRA, provide valuable information on dynamic changes in aneurysm morphology that might have an important impact on endograft selection. During follow-up, imaging of the graft and aneurysm is of utmost importance to identify patients in need of secondary intervention. This has led...... to rigorous follow-up protocols including duplex ultrasound and regular CT examinations. The use of these intense follow-up protocols has recently been questioned because of high radiation dose and the frequent use of nephrotoxic contrast agents. New imaging modalities like contrast enhanced DUS, dynamic MR...

  13. Externally Delivered Focused Ultrasound for Renal Denervation.

    Science.gov (United States)

    Neuzil, Petr; Ormiston, John; Brinton, Todd J; Starek, Zdenek; Esler, Murray; Dawood, Omar; Anderson, Thomas L; Gertner, Michael; Whitbourne, Rob; Schmieder, Roland E

    2016-06-27

    The aim of this study was to assess clinical safety and efficacy outcomes of renal denervation executed by an externally delivered, completely noninvasive focused therapeutic ultrasound device. Renal denervation has emerged as a potential treatment approach for resistant hypertension. Sixty-nine subjects received renal denervation with externally delivered focused ultrasound via the Kona Medical Surround Sound System. This approach was investigated across 3 consecutive studies to optimize targeting, tracking, and dosing. In the third study, treatments were performed in a completely noninvasive way using duplex ultrasound image guidance to target the therapy. Short- and long-term safety and efficacy were evaluated through use of clinical assessments, magnetic resonance imaging scans prior to and 3 and 24 weeks after renal denervation, and, in cases in which a targeting catheter was used to facilitate targeting, fluoroscopic angiography with contrast. All patients tolerated renal denervation using externally delivered focused ultrasound. Office blood pressure (BP) decreased by 24.6 ± 27.6/9.0 ± 15.0 mm Hg (from baseline BP of 180.0 ± 18.5/97.7 ± 13.7 mm Hg) in 69 patients after 6 months and 23.8 ± 24.1/10.3 ± 13.1 mm Hg in 64 patients with complete 1-year follow-up. The response rate (BP decrease >10 mm Hg) was 75% after 6 months and 77% after 1 year. The most common adverse event was post-treatment back pain, which was reported in 32 of 69 patients and resolved within 72 h in most cases. No intervention-related adverse events involving motor or sensory deficits were reported. Renal function was not altered, and vascular safety was established by magnetic resonance imaging (all patients), fluoroscopic angiography (n = 48), and optical coherence tomography (n = 5). Using externally delivered focused ultrasound and noninvasive duplex ultrasound, image-guided targeting was associated with substantial BP reduction without any major safety signals. Further

  14. Characterization of microstructure and texture across dissimilar super duplex/austenitic stainless steel weldment joint by super duplex filler metal

    Energy Technology Data Exchange (ETDEWEB)

    Eghlimi, Abbas, E-mail: a.eghlimi@ma.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Shamanian, Morteza [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Eskandarian, Masoomeh [Department of Materials Engineering, Shiraz University, Shiraz 71348-51154 (Iran, Islamic Republic of); Zabolian, Azam [Department of Natural Resources, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Szpunar, Jerzy A. [Department of Mechanical Engineering, University of Saskatchewan, Saskatoon SK S7N 5A9 (Canada)

    2015-08-15

    In the present paper, microstructural changes across an as-welded dissimilar austenitic/duplex stainless steel couple welded by a super duplex stainless steel filler metal using gas tungsten arc welding process is characterized with optical microscopy and electron back-scattered diffraction techniques. Accordingly, variations of microstructure, texture, and grain boundary character distribution of base metals, heat affected zones, and weld metal were investigated. The results showed that the weld metal, which was composed of Widmanstätten austenite side-plates and allotriomorphic grain boundary austenite morphologies, had the weakest texture and was dominated by low angle boundaries. The welding process increased the ferrite content but decreased the texture intensity at the heat affected zone of the super duplex stainless steel base metal. In addition, through partial ferritization, it changed the morphology of elongated grains of the rolled microstructure to twinned partially transformed austenite plateaus scattered between ferrite textured colonies. However, the texture of the austenitic stainless steel heat affected zone was strengthened via encouraging recrystallization and formation of annealing twins. At both interfaces, an increase in the special character coincident site lattice boundaries of the primary phase as well as a strong texture with <100> orientation, mainly of Goss component, was observed. - Graphical abstract: Display Omitted - Highlights: • Weld metal showed local orientation at microscale but random texture at macroscale. • Intensification of <100> orientated grains was observed adjacent to the fusion lines. • The austenite texture was weaker than that of the ferrite in all duplex regions. • Welding caused twinned partially transformed austenites to form at SDSS HAZ. • At both interfaces, the ratio of special CSL boundaries of the primary phase increased.

  15. THE INFLUENCE OF POSTHEAT TREATMENT ON FERRITE REDISTRIBUTION IN DUPLEX STEELS ELECTRON BEAM WELDS

    Directory of Open Access Journals (Sweden)

    Zita Iždinská

    2009-04-01

    Full Text Available The duplex stainless steel is two-phase steel with the structure composed of austenite and ferrite with optimum austenite/ferrite proportion 50%. At present, classical arc processes for welding duplex steels are generally regarded as acceptable. On the other hand electron and laser beam welding is up to now considered less suitable for welding duplex steels. The submitted work presents the results of testing various thermal conditions at welding duplex stainless steel with electron beam. It was shown, that application of suitable postheat made possible to reduce the ferrite content in weld metal.

  16. Residual stresses and fatigue in a duplex stainless steel

    International Nuclear Information System (INIS)

    Johansson, Johan

    1999-01-01

    Duplex stainless steels, consisting of approximately equal amounts of austenite and ferrite, often combine the best features of austenitic and ferritic stainless steels. They generally have good mechanical properties, including high strength and ductility, and the corrosion resistance is often better than conventional austenitic grades. This has lead to a growing use of duplex stainless steels as a material in mechanically loaded constructions. However, detailed knowledge regarding its mechanical properties and deformation mechanisms are still lacking. In this thesis special emphasis has been placed on the residual stresses and their influence on mechanical behaviour of duplex stainless steels. Due to the difference in coefficient of thermal expansion between the two phases, tensile microstresses are found in the austenitic phase and balancing compressive microstresses in the ferritic phase. The first part of this thesis is a literature survey, which will give an introduction to duplex stainless steels and review the fatigue properties of duplex stainless steels and the influence of residual stresses in two-phase material. The second part concerns the evolution of the residual stress state during uniaxial loading. Initial residual stresses were found to be almost two times higher in the transverse direction compared to the rolling direction. During loading the absolute value of the microstresses increased in the macroscopic elastic regime but started to decrease with increasing load in the macroscopic plastic regime. A significant increase of the microstresses was also found to occur during unloading. Finite element simulations also show stress variation within one phase and a strong influence of both the elastic and plastic anisotropy of the individual phases on the simulated stress state. In the third part, the load sharing between the phases during cyclic loading is studied. X-ray diffraction stress analysis and transmission electron microscopy show that even if

  17. Residual stresses and fatigue in a duplex stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, Johan

    1999-05-01

    Duplex stainless steels, consisting of approximately equal amounts of austenite and ferrite, often combine the best features of austenitic and ferritic stainless steels. They generally have good mechanical properties, including high strength and ductility, and the corrosion resistance is often better than conventional austenitic grades. This has lead to a growing use of duplex stainless steels as a material in mechanically loaded constructions. However, detailed knowledge regarding its mechanical properties and deformation mechanisms are still lacking. In this thesis special emphasis has been placed on the residual stresses and their influence on mechanical behaviour of duplex stainless steels. Due to the difference in coefficient of thermal expansion between the two phases, tensile microstresses are found in the austenitic phase and balancing compressive microstresses in the ferritic phase. The first part of this thesis is a literature survey, which will give an introduction to duplex stainless steels and review the fatigue properties of duplex stainless steels and the influence of residual stresses in two-phase material. The second part concerns the evolution of the residual stress state during uniaxial loading. Initial residual stresses were found to be almost two times higher in the transverse direction compared to the rolling direction. During loading the absolute value of the microstresses increased in the macroscopic elastic regime but started to decrease with increasing load in the macroscopic plastic regime. A significant increase of the microstresses was also found to occur during unloading. Finite element simulations also show stress variation within one phase and a strong influence of both the elastic and plastic anisotropy of the individual phases on the simulated stress state. In the third part, the load sharing between the phases during cyclic loading is studied. X-ray diffraction stress analysis and transmission electron microscopy show that even if

  18. Combined diagnosis of lateral cervical masses by RI-scintigraphy, ultrasound and CT-scanning

    International Nuclear Information System (INIS)

    Yang, Kuang-Tsuong; Yamashita, Toshio; Sasa, Hidehiko

    1984-01-01

    Careful palpation, plain X-rays and angiography are useful in the diagnosis of lateral cervical masses, but accurate preoperative evaluation sometimes needs further examinations. Recently several new auxiliary procedures have become available such as RI-scintigraphy, Ultrasound, and CT-scanning but even these may not be sufficient when used singly. When all these procedures were combined preoperatively in the case of lateral cervical masses and the results were compared with the findings at time of surgery and the pathology of the extirpated masses, acurate preoperative diagnose were possible. (author)

  19. Impaired anastomotic healing after preoperative radiotherapy ...

    African Journals Online (AJOL)

    Background. Patients with rectal carcinoma undergoing total mesorectal excision (TME) have a lower recurrence rate with preoperative radiotherapy (RT). The aim of this study was to assess the side-effects in patients who had preoperative RT compared with those who did not receive it (because of palliative resections, ...

  20. Preoperative Smoking Status and Postoperative Complications

    DEFF Research Database (Denmark)

    Pedersen, Marie Grønkjær; Eliasen, Marie; Skov-Ettrup, Lise Skrubbeltrang

    2014-01-01

    To systematically review and summarize the evidence of an association between preoperative smoking status and postoperative complications elaborated on complication type.......To systematically review and summarize the evidence of an association between preoperative smoking status and postoperative complications elaborated on complication type....