scholarly journals Quantitative analysis of concrete on the basis of fuzzy set and computerised tomography number

2020 ◽  
Vol 24 (6 Part B) ◽  
pp. 3907-3913
Author(s):  
Jian-Yin Fang ◽  
Na Li ◽  
Fei Qu ◽  
Zhan-Shuang Dou ◽  
Shu-Tian Li
Keyword(s):  
Uniaxial Compression ◽  
Ct Scanning ◽  
Spiral Ct ◽  
Hardened Cement ◽  
Ct Scanner ◽  
Ct Number ◽  
Portable Power ◽  
Power Loading ◽  
Aggregate Rate ◽  
Ct Test

In this study, the portable power loading device and medical Marconi M8000 spiral CT scanner are used to conduct the uniaxial compression CT scanning test of the concrete. The concrete porosity, hardened cement rate, and aggregate rate are defined, and the variation law of the concrete is analyzed in the uniaxial compression CT test. The proposed method is considered to utilize the value of each CT number, to realize the quantitative partition of the various components of concrete, and to quantitatively evaluate the damage evolution law of the concrete and strain localization during stress. It is shown that damage at the middle section increased from inside to the outside in the uniaxial compression CT test of the concrete.

scholarly journals Numerical Reconstruction Model and Simulation Study of Concrete Based on Damaged Partition Theory and CT Number

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4070
Author(s):  
Jianyin Fang ◽  
You Pan ◽  
Faning Dang ◽  
Xiyuan Zhang ◽  
Jie Ren ◽  
...  
Keyword(s):  
Uniaxial Compression ◽  
Hardened Cement ◽  
Shear Cracks ◽  
Ct Scanner ◽  
Ct Number ◽  
Static Compression ◽  
Partition Theory ◽  
Compression Load ◽  
Ct Test ◽  
Concrete Model

The applicability of mesoscopic models plays an important role in studying the mesoscopic mechanical properties of concrete. In this study, the computerized tomography (CT) test of concrete under uniaxial compression conditions is conducted using a portable dynamic loading equipment developed by Xi’an University of Technology and a medical Marconi M8000 spiral CT scanner. On the basis of damage partition theory, a probabilistic statistical method for determining threshold values is proposed, and a CT test images is obtained and divided into aggregate, hardened cement and hole-crack areas. A ‘structural random numerical concrete model’ is also established on the basis of the coordinates of each pixel unit in CT images. Uniaxial static compression and tensile numerical simulation tests are conducted. Results show that the structural random numerical concrete model can not only reflect the microscopic composition of concrete but also the interfacial transition zone (ITZ) between aggregate and mortar. The ITZ thickness is approximately 0.04 mm, which is close to the real concrete sample ITZ thickness (approximately 10–50 μm). In the two tests, the specimen damage starts from the initial defects, and the damage crack expands through the weaker ITZ around the aggregate. No matter under the action of static tension or compression load, the damage cracks of the sample almost never pass through the aggregate. Most of the many cracks in uniaxial compression are shear cracks. However, many cracks form at the beginning of uniaxial tension, and only one main crack, which is roughly perpendicular to the loading direction, exists in the end.

1522: Utility of Preoperative 3-D Reconstruction of Pelvic Vasculature using Multi-Detector Spiral CT Scanning in Treatment Planning for Robotic Prostatectomy

2005 ◽  
Vol 173 (4S) ◽  
pp. 412-412
Author(s):  
Ashutosh Tewari ◽  
Assaad El-Hakim ◽  
Peter N. Schlegel ◽  
Mani Menon ◽  
Deirdre M. Coll
Keyword(s):  
Treatment Planning ◽  
Ct Scanning ◽  
Spiral Ct ◽  
Robotic Prostatectomy

Endoluminal Graft Exclusion of a Proximal Para-Anastomotic Pseudoaneurysm following Aortobifemoral Bypass

1997 ◽  
Vol 4 (1) ◽  
pp. 88-94 ◽  
Author(s):  
Rodney A. White ◽  
Carlos E. Donayre ◽  
Irwin Walot ◽  
Eric Wilson ◽  
George Jackson ◽  
...  
Keyword(s):  
Medical Condition ◽  
Ct Scanning ◽  
Abdominal Ultrasound ◽  
Spiral Ct ◽  
Aortobifemoral Bypass ◽  
Anastomotic Pseudoaneurysm ◽  
Left Limb ◽  
Work Up ◽  
Abdominal Ultrasound Examination

Purpose: To describe a case of endoluminal graft exclusion of a proximal para-anastomotic pseudoaneurysm that occurred 17 years following aortobifemoral bypass for occlusive disease. Methods and Results: The lesion was found on abdominal ultrasound examination as part of a work-up for acute abdominal pain and upper gastrointestinal bleeding in a 67-year-old male. A 5-cm saccular pseudoaneurysm was confirmed by preintervention aortography and spiral computed tomography (CT) scanning. Because of the patient's acute symptoms and high-risk medical condition (cardiomyopathy), he was deemed a candidate for endoluminal bypass. At the time of intervention, intravascular ultrasound (IVUS) interrogation identified a 3.5-cm-long separation of the existing aortic graft from the proximal aortic stump with a large pseudoaneurysm. The lesion was isolated and repaired by placement of an aortic-to-right iliac endoluminal bypass, ligation of the left limb of the aortofemoral graft, and femorofemoral bypass to restore blood flow to the lower extremities. Spiral CT scans at 48 hours and 3 months following the procedure confirmed complete isolation of the lesion. Conclusions: This case illustrates the feasibility of endografting for repair of aortic para-anastomotic pseudoaneurysms, and it also highlights the potential role of IVUS imaging in endoluminal graft deployment.

scholarly journals Time-Enhancement Curve of Four-Dimensional Computed Tomography Predicts Aneurysm Enlargement with Type-II Endoleak after Endovascular Aneurysm Repair

Aorta ◽  
2020 ◽  
Vol 08 (02) ◽  
pp. 029-034
Author(s):  
Yunosuke Nishihara ◽  
Kota Mitsui ◽  
Shinya Azama ◽  
Daisuke Okamoto ◽  
Manabu Sato ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Equilibrium Phase ◽  
Endovascular Aneurysm Repair ◽  
Three Dimensional ◽  
Type Ii ◽  
Ct Scanner ◽  
Stable Group ◽  
Ct Number ◽  
4D Ct ◽  
Aneurysm Repair

Abstract Objective We investigated the hemodynamic features of Type-II endoleaks after endovascular aneurysm repair (EVAR) using four-dimensional (4D) computed tomography (CT) to identify patients with aneurysm enlargement. Methods During a 13-month period (January 2017–January 2018) at our institution, we performed 4D-CT examinations in 13 patients after EVAR because of suspected Type-II endoleaks. Three patients were excluded from the study because of other endoleaks or absence of detectable endoleaks. The ramaining 10 patients were divided into two groups: enlargement group (n = 4), in which the aneurysm volume increased, and stable group (n = 6), in which the aneurysm remained stable or shrank. A CT scanner and three-dimensional workstation were used. All images were obtained using a consistent protocol (22 phase scans using the test bolus tracking method). We analyzed the hemodynamics of the endoleak cavity (EC) relative to those of the aorta and evaluated the time-enhancement curves (TECs) using measurement protocols. The strengths of correlations between these factors in the two groups were analyzed statistically. Results TECs in the enlargement group showed a more gradual curve, and the upslope, the gradient of TEC in the ascending phase and the upslope index were significantly more gradual than those in the stable group (p = 0.0247, 0.0243). The EC washout and the EC washout index were also more gradual than in the stable group's (p = 0.019, 0.019). The enhancement duration was longer in the former than in the latter (80%, p = 0.0195; 70%, p = 0.0159; 60%, p = 0.0159). The CT number in the equilibrium phase was larger in the enlargement group than in the stable group (p = 0.019). Conclusion The 4D-CT is useful for predicting aneurysm enlargement with Type-II endoleaks after EVAR.

scholarly journals CT lymphography for sentinel lymph node mapping of clinically N0 early oral cancer

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Satomi Sugiyama ◽  
Toshinori Iwai ◽  
Toshiharu Izumi ◽  
Keita Ishiguro ◽  
Junichi Baba ◽  
...  
Keyword(s):  
Lymph Node ◽  
Sentinel Lymph Node ◽  
Oral Cancer ◽  
Lymph Nodes ◽  
Contrast Medium ◽  
Sentinel Lymph Node Mapping ◽  
Ct Scanning ◽  
Optimal Timing ◽  
Ct Scanner ◽  
Lymph Node Mapping

Abstract Background The objectives of this retrospective study were to evaluate the usefulness of computed tomography lymphography (CTL) and to clarify the optimal timing of CTL in sentinel lymph node (SLN) mapping of clinically N0 early oral cancer. Methods Twenty patients with clinically N0 early oral cancer underwent CTL with a 128 multi-detector row CT scanner to detect SLN the day before resection of primary tumor and SLN biopsy with indocyanine green (ICG) fluorescence guidance. CT scanning was performed in the first 10 patients at 2, 5, and 10 min after submucosal injection of iopamidol and in the remaining 10 patients at 2, 3.5, 5, and 10 min after the injection of contrast medium. We evaluated the SLN detection rate at each scan timing and the number and location of SLNs. We evaluated whether CTL-enhanced SLNs could be identified intraoperatively as ICG fluorescent lymph nodes. Results SLNs were detected by CTL in 19 of the 20 patients (95.0%), and the mean number of SLNs was 2 (range, 1–4). All SLNs were located on the ipsilateral side; 35 of 37 SLNs were located at level I and II, and 2 SLNs were lingual lymph nodes. All SLNs could be detected 2 min and 3.5–5 min after contrast medium injection, and CTL-enhanced SLNs could be identified intraoperatively as fluorescent lymph nodes. Conclusions CTL could facilitate the detection of SLNs in early oral cancer, and the optimal timing of CT scanning was at 2 and 5 min after injection of contrast medium.

Traumatically Induced Brain Stem Hemorrhage and the Computerized Tomographic Scan

Neurosurgery ◽  
1979 ◽  
Vol 4 (2) ◽  
pp. 115-124 ◽  
Author(s):  
Paul R. Cooper ◽  
Kenneth Maravilla ◽  
Joel Kirkpatrick ◽  
Sarah F. Moody ◽  
Frederick H. Sklar ◽  
...  
Keyword(s):  
Ct Scan ◽  
Brain Stem ◽  
Thin Section ◽  
Ex Vivo ◽  
Ct Scanning ◽  
Volume Effect ◽  
Brain Parenchyma ◽  
Ct Scanner ◽  
Cross Sectional ◽  
The Brain

Abstract The computerized tomographic (CT) scan has revolutionized the management of cerebral trauma. Nevertheless, visualization of traumatically induced lesions of the brain stem by the CT scanner remains difficult. Seven patients with autopsy or CT evidence of brain stem hemorrhage were identified over a 1-year period. In six of these patients, brain stem hemorrhage could be defined by CT scan. As part of a prospective study of CT changes after head injury, we performed serial CT scans on six of the seven patients. Clinical experience shows that timing is important for identification of these lesions and that inability to visualize brain stem hematomas may occur because of the development of hematomas after CT scanning, evolution of hemorrhagic lesions that makes them isodense with the surrounding brain stem, patient movement, and technical factors such as the partial volume effect. Experimental injection of fresh blood into the pons and midbrain of cadavers shows that lesions as small as 0.1 ml in volume may be visualized by ex vivo thin section CT scanning techniques. However, the character and anatomical configuration of the hemorrhage may be as important in determining CT visualization as is the volume of the hemorrhage. For example, a hematoma displacing the brain parenchyma was visualized, but a similar-sized small hemorrhage that had diffused through the brain stem tissues was not. Although many of the experimentally placed lesions extended over a rostral-caudal length of 15 mm or more in the brain stem, no lesion was seen on more than three thin section scans. This is explained by the presence of lesions that, although extensive in a rostral-caudal direction, had relatively small cross sectional areas available for identification by the CT scanner. The small size of traumatic lesions of the brain stem and their proximity to bony structures at the base of the skull are not insurmountable obstacles to visualization of brain stem hemorrhages. Serial scanning and the application of thin section computed tomography will lead to identification of most of these lesions.

scholarly journals Assessment of Hemodynamics in a Rat Model of Liver Cirrhosis with Precancerous Lesions Using Multislice Spiral CT Perfusion Imaging

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Guolin Ma ◽  
Rongjie Bai ◽  
Huijie Jiang ◽  
Xuejia Hao ◽  
Zaisheng Ling ◽  
...  
Keyword(s):  
Liver Cirrhosis ◽  
Rat Model ◽  
Ct Perfusion ◽  
Precancerous Lesions ◽  
Mean Transit Time ◽  
Ct Scanning ◽  
Spiral Ct ◽  
Control Group ◽  
Hemodynamic Changes ◽  
Multislice Spiral Ct

Rationale and Objectives. To develop an optimal scanning protocol for multislice spiral CT perfusion (CTP) imaging to evaluate hemodynamic changes in liver cirrhosis with diethylnitrosamine- (DEN-) induced precancerous lesions.Materials and Methods. Male Wistar rats were randomly divided into the control group (n=80) and the precancerous liver cirrhosis group (n=40). The control group received saline injection and the liver cirrhosis group received 50 mg/kg DENi.p.twice a week for 12 weeks. All animals underwent plain CT scanning, CTP, and contrast-enhanced CT scanning. Scanning parameters were optimized by adjusting the diatrizoate concentration, the flow rate, and the delivery time. The hemodynamics of both groups was further compared using optimized multislice spiral CTP imaging.Results. High-quality CTP images were obtained with following parameters: 150 kV; 150 mAs; 5 mm thickness, 5 mm interval; pitch, 1; matrix,512×512; and FOV, 9.6 cm. Compared to the control group, the liver cirrhosis group had a significantly increased value of the hepatic arterial fraction and the hepatic artery perfusion (P<0.05) but significantly decreased hepatic portal perfusion and mean transit time (P<0.05).Conclusion. Multislice spiral CTP imaging can be used to evaluate the hemodynamic changes in the rat model of liver cirrhosis with precancerous lesions.

Skeletal SPECT/CT of the peripheral extremities -interdisciplinary approach in orthopaedic disorders-first clinical results

Open Medicine ◽  
2007 ◽  
Vol 2 (4) ◽  
pp. 499-510 ◽  
Author(s):  
Wolfgang Wuest ◽  
Torsten Kuwert ◽  
Markus Grunewald ◽  
Werner Bautz ◽  
Raimund Forst ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Hybrid Imaging ◽  
Single Photon ◽  
Photon Emission ◽  
Interdisciplinary Approach ◽  
Spiral Ct ◽  
Emission Computed Tomography ◽  
Main Diagnosis ◽  
Ct Scanner ◽  
Lesion Localization

AbstractBone scintigraphy, although quite sensitive to detect skeletal lesions, has a comparatively low specificity. Hybrid-cameras combining single-photon emission computed tomography (SPECT) and spiral-CT offer the opportunity to correlate scintigraphic information with high-quality visualization of morphology in one session. This may lead to an improvement in diagnostic accuracy and anatomic lesion localization. We present 11 patients, who underwent SPECT/CT of the feet (n=10) and hands (n = 1). The examinations were performed due to pain in foot or hand with the following suspected clinical diagnoses: arthrosis (n=1); fracture (n=3); osteomyelitis (n=4); reflex dystrophia (n=1); and, pain of unclear origin (n=2). All patients underwent SPECT/CT hybrid imaging using a dual-headed SPECT camera integrated with a 2-slice spiral CT scanner in one gantry. SPECT, CT, and SPECT/CT were evaluated independently from each other with respect to main diagnosis, anatomic lesion localization, and detection of a possible additional diagnosis. SPECT/CT improved lesion localization in 8 of 11 patients (73%) in comparison to SPECT alone, and in 4 of 11 patients (36%) in comparison to CT alone. Diagnostic accuracy was improved in 4 of 11 patients (36%) in comparison to either SPECT or CT alone. In conclusion, skeletal SPECT/CT improves diagnostic accuracy and lesion localization of orthopedic disorders in the feet and hands. The obtained results encouraged extensive studies to further investigate the potential gain in diagnostic accuracy brought about by SPECT/spiral-CT hybrid imaging in orthopedic disorders of the peripheral extremities.

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