The Interobserver Agreement between Residents and Experienced Radiologists for Detecting Pulmonary Embolism and DVT with Using CT Pulmonary Angiography and Indirect CT Venography

Ulas Savas Yavas,Cuneyt Calisir,Ibrahim Ragip Ozkan 대한영상의학회 2008 Korean Journal of Radiology Vol.9 No.6

Objective: We wanted to prospectively evaluate the interobserver agreement between radiology residents and expert radiologists for interpreting CT images for making the diagnosis of pulmonary embolism (PE). Materials and Methods: We assessed 112 consecutive patients, from April 2007 to August 2007, who were referred for combined CT pulmonary angiography and indirect CT venography for clinically suspected acute PE. CT scanning was performed with a 64×0.5 collimation multi-detector CT scanner. The CT studies were initially interpreted by the radiology residents alone and then the CT images were subsequently interpreted by a consensus of the resident plus an experienced general radiologist and an experienced chest radiologist. Results: Two of the 112 CTs were unable to be interpreted (1.7%). Pulmonary artery clots were seen on 36 of the thoracic CT angiographies (32%). The interobserver agreement between the radiology residents and the consensus interpretation was good (a kappa index of 0.73). All of the disagreements (15 cases) were instances of overcall by the resident on the initial interpretation. Deep venous thrombosis was detected in 72% (26 of 36) of the patients who had PE seen on thoracic CT. The initial and consensus interpretations of the CT venography images disagreed for two cases (kappa statistic: 0.96). Conclusion: It does not seem adequate to base the final long-term treatment of PE on only the resident’s reading, as false positives occurred in 13% of such cases. Timely interpretation of the CT pulmonary angiography and CT venography images should be performed by experienced radiologists for the patients with suspected PE. Objective: We wanted to prospectively evaluate the interobserver agreement between radiology residents and expert radiologists for interpreting CT images for making the diagnosis of pulmonary embolism (PE). Materials and Methods: We assessed 112 consecutive patients, from April 2007 to August 2007, who were referred for combined CT pulmonary angiography and indirect CT venography for clinically suspected acute PE. CT scanning was performed with a 64×0.5 collimation multi-detector CT scanner. The CT studies were initially interpreted by the radiology residents alone and then the CT images were subsequently interpreted by a consensus of the resident plus an experienced general radiologist and an experienced chest radiologist. Results: Two of the 112 CTs were unable to be interpreted (1.7%). Pulmonary artery clots were seen on 36 of the thoracic CT angiographies (32%). The interobserver agreement between the radiology residents and the consensus interpretation was good (a kappa index of 0.73). All of the disagreements (15 cases) were instances of overcall by the resident on the initial interpretation. Deep venous thrombosis was detected in 72% (26 of 36) of the patients who had PE seen on thoracic CT. The initial and consensus interpretations of the CT venography images disagreed for two cases (kappa statistic: 0.96). Conclusion: It does not seem adequate to base the final long-term treatment of PE on only the resident’s reading, as false positives occurred in 13% of such cases. Timely interpretation of the CT pulmonary angiography and CT venography images should be performed by experienced radiologists for the patients with suspected PE.

Discrete singular convolution for buckling analyses of plates and columns

Civalek, Omer,Yavas, Altug Techno-Press 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.29 No.3

In the present study, the discrete singular convolution (DSC) method is developed for buckling analysis of columns and thin plates having different geometries. Regularized Shannon's delta (RSD) kernel is selected as singular convolution to illustrate the present algorithm. In the proposed approach, the derivatives in both the governing equations and the boundary conditions are discretized by the method of DSC. The results obtained by DSC method were compared with those obtained by the other numerical and analytical methods.

The Relationship between the Breast Arterial Calcification Detected by Mammography and the Hypertensive Retinopathy in Hypertensive Women

Cuneyt Calisir,Ulas Savas Yavas,Nazmiye Erol 대한영상의학회 2008 Korean Journal of Radiology Vol.9 No.4

Objective: The purpose of this study was to investigate the relationship between the breast arterial calcification (BAC) detected by mammograms and the hypertensive retinopathy (HR) in hypertensive women who underwent ophthalmologic examination. Materials and Methods: Screening mammography was performed in 99 hypertensive women and these women also underwent an ophthalmologic examination. The presence of arterial calcification and the number of calcified blood vessels in each breast were evaluated. The grade of HR was determined. The presence of BAC and the number of blood vessels involved was compared according to the presence of HR and the grade of HR. Results: Among the 99 patients, HR was detected in 70 patients, and of these 70 patients, 42 patients had grade I HR and 28 had grade II HR. BAC was detected in 54 cases. Forty-six patients with HR (66%) and eight patients without HR (27%) were diagnosed with BAC after they underwent mammographic examination. The prevalence of BAC in the subjects who had HR was statistically higher than that in those subjects who did not have HR (p < 0.01). The grade of HR was not significantly associated with BAC (p > 0.05). The positive predictive value of the BAC detected on mammography for HR was 0.80 in those subjects who were 60 years old. Conclusion: The detection of BAC by mammography is associated with an increased risk of HR, and particularly for patients after the age of 60. The findings of BAC may be related to hypertensive end-organ damage, and performing mammograms might contribute to predicting the presence of ophthalmologic hypertensive complications in these patients. Objective: The purpose of this study was to investigate the relationship between the breast arterial calcification (BAC) detected by mammograms and the hypertensive retinopathy (HR) in hypertensive women who underwent ophthalmologic examination. Materials and Methods: Screening mammography was performed in 99 hypertensive women and these women also underwent an ophthalmologic examination. The presence of arterial calcification and the number of calcified blood vessels in each breast were evaluated. The grade of HR was determined. The presence of BAC and the number of blood vessels involved was compared according to the presence of HR and the grade of HR. Results: Among the 99 patients, HR was detected in 70 patients, and of these 70 patients, 42 patients had grade I HR and 28 had grade II HR. BAC was detected in 54 cases. Forty-six patients with HR (66%) and eight patients without HR (27%) were diagnosed with BAC after they underwent mammographic examination. The prevalence of BAC in the subjects who had HR was statistically higher than that in those subjects who did not have HR (p < 0.01). The grade of HR was not significantly associated with BAC (p > 0.05). The positive predictive value of the BAC detected on mammography for HR was 0.80 in those subjects who were 60 years old. Conclusion: The detection of BAC by mammography is associated with an increased risk of HR, and particularly for patients after the age of 60. The findings of BAC may be related to hypertensive end-organ damage, and performing mammograms might contribute to predicting the presence of ophthalmologic hypertensive complications in these patients.

Experimental Investigation of the Explosive Evaporation of Liquids on a Solid Surface Heated by Pulsed Ultraviolet Laser Irradiation

H. K. Park,C. P. Grigoropoulos,O. Yavas,W. P. Leung,C. Poon,A. C. Tam 대한기계학회 1993 International Symposium on Transport Phenomena in Vol.2 No.1

Mazabraud’s Syndrome Coexisting with a Uterine Tumor Resembling an Ovarian Sex Cord Tumor (UTROSCT): a Case Report

Cuneyt Calisir,Ulukan Inan,Ulas Savas Yavas,Serap Isiksoy,Tamer Kaya 대한영상의학회 2007 Korean Journal of Radiology Vol.8 No.5

The association of intramuscular myxoma and fibrous dysplasia is a rare disease known as Mazabraud's syndrome. We present a case of Mazabraud's syndrome coexisting with a uterine tumor and resembling an ovarian sex cord tumor (UTROSCT). This uterine tumor showed a high mitotic index and cytological atypia. To the best of our knowledge, the coexistence of the two different entities has not been reported in the literature.

Experimental and numerical aerodynamic investigation of a prototype vehicle

Akansu, Selahaddin Orhan,Akansu, Yahya Erkan,Dagdevir, Toygun,Daldaban, Ferhat,Yavas, Feridun Techno-Press 2015 Wind and Structures, An International Journal (WAS Vol.20 No.6

This study presents experimental and numerical aerodynamic investigation of a prototype vehicle. Aerodynamics forces examined which exerted on a prototype. This experimental study was implemented in a wind tunnel for the Reynolds number between $10^5-3.1{\times}10^5$. Numerical aerodynamic analysis of the vehicle is conducted for different Reynolds number by using FLUENT CFD software, with the k-$\varepsilon$ realizable turbulence model. The studied model aims at verifying the aerodynamic forces between experimental and numerical results. After the Reynolds number of $2.8{\times}10^5$, the drag coefficient obtained experimentally becomes independent of Reynolds number and has a value of 0.25.

Experimental and numerical aerodynamic investigation of a prototype vehicle

Selahaddin Orhan Akansu,Yahya Erkan Akansu,Toygun Dagdevir,Ferhat Daldaban,Feridun Yavas 한국풍공학회 2015 Wind and Structures, An International Journal (WAS Vol.20 No.6

This study presents experimental and numerical aerodynamic investigation of a prototype vehicle. Aerodynamics forces examined which exerted on a prototype. This experimental study was implemented in a wind tunnel for the Reynolds number between 105-3.1x105. Numerical aerodynamic analysis of the vehicle is conducted for different Reynolds number by using FLUENT CFD software, with the k-ε realizable turbulence model. The studied model aims at verifying the aerodynamic forces between experimental and numerical results. After the Reynolds number of 2.8x105, the drag coefficient obtained experimentally becomes independent of Reynolds number and has a value of 0.25.

A multi-institutional analysis of sequential versus ‘sandwich’ adjuvant chemotherapy and radiotherapy for stage IIIC endometrial carcinoma

Cem Onal,Sezin Yuce Sari,Berna Akkus Yildirim,Guler Yavas,Melis Gultekin,Ozan Cem Guler,Serap Akyurek,Ferah Yildiz 대한부인종양학회 2019 Journal of Gynecologic Oncology Vol.30 No.3

Objective: To analyze the outcomes of sequential or sandwich chemotherapy (ChT) and radiotherapy (RT) in patients with node-positive endometrial cancer (EC). Methods: Data from 4 centers were collected retrospectively for 179 patients with stage IIIC EC treated with postoperative RT and ChT (paclitaxel and carboplatin). Patients were either treated with 6 cycles of ChT followed by RT (sequential arm; 96 patients) or with 3 cycles of ChT, RT, and an additional 3 cycles of ChT (sandwich arm; 83 patients). Prognostic factors affecting overall survival (OS) and progression-free survival (PFS) were analyzed. Results: The 5-year OS and PFS rates were 64% and 59%, respectively, with a median followup of 41 months (range, 5–167 months). The 5-year OS rates were significantly higher in the sandwich than sequential arms (74% vs. 56%; p=0.03) and the difference for 5-year PFS rates was nearly significant (65% vs. 54%; p=0.05). In univariate analysis, treatment strategy, age, International Federation of Gynecology and Obstetrics (FIGO) stage, pathology, rate of myometrial invasion, and grade were prognostic factors for OS and PFS. In multivariate analysis, non-endometrioid histology, advanced FIGO stage, and adjuvant sequential ChT and RT were negative predictors for OS, whereas only non-endometrioid histology was a prognostic factor for PFS. Conclusion: Postoperative adjuvant ChT and RT for stage IIIC EC patients, either given sequentially or sandwiched, offers excellent clinical efficacy and acceptably low toxicity. Our data support the superiority of the sandwich regimen compared to the sequential strategy in stage IIIC EC patients for OS.

Discrete singular convolution for buckling analyses of plates and columns

Ömer Civalek,Altu Yava 국제구조공학회 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.29 No.3

In the present study, the discrete singular convolution (DSC) method is developed for buckling analysis of columns and thin plates having different geometries. Regularized Shannon’s delta (RSD) kernel is selected as singular convolution to illustrate the present algorithm. In the proposed approach, the derivatives in both the governing equations and the boundary conditions are discretized by the method of DSC. The results obtained by DSC method were compared with those obtained by the other numerical and analytical methods.