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Purpose: To quantify left ventricular function derived from retrospectively ECG-gated multislice spiral CT (MSCT) data sets in comparison to MRI. Materials and Methods: In 16 patients (14 males, 2 females, mean age 56.8 #+-# 11.5 years), retrospectively ECG-gated MSCT angiography of the coronary arteries and breath-hold steady state free precession cine MRI were performed. From MSCT data-sets, 20 axial image series were reconstructed every 5% of the RR interval. Multiplanar images were reformatted in the short axis orientation from axial images. End-systolic and end-diastolic images were selected. From these images end-systolic volume (ESV), end-diastolic volume (EDV) and stroke volume (SV) as well as the ejection fraction (EF) and myocardial mass (MM) were determined using the Simpson's method and compared with MRI. Furthermore, image quality was assessed for both imaging modalities using a four point grading scale. ...

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The standard protocol in multislice spiral CT (MSCT) angiography for coronary arteries with fixed tube current-time settings leads to an overexposure and thus to an unnecessary high radiation dose in patients with lower weight when compared to heavier patients. The purpose of this study was to estimate the effect of reducing the radiation dose by adapting the tube current-time settings individually. Fifty patients underwent retrospectively ECG-gated MSCT of the heart. In 25 patients (group A_1) a standard protocol with constant tube current-time settings was used (4 x 1-mm collimation, 120 kV, 400 mAs_e_f_f). Subsequently, artificial image noise was added to the data of these patients simulating a directive for weight-adapted tube current-time settings (group A_2). In the other 25 patients (group B) an alternative protocol with individually weight-adapted tube current-time settings was applied. The data of all groups were evaluated by a ...

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Purpose: For planning the therapeutic strategies and estimating the prognosis in esophageal cancer, N-staging is very important. To date, MRI still is of minor importance as imaging modality of the mediastinum despite promising developments in the past, like ECG-gating or 'averaging' sequences, e.g. LOTA (Long-term averaging), which facilitate mediastinal and thoracic MR-imaging. In a prospective approach, the value of MRI based N-staging was examined with respect to LOTA-sequences. Material and Methods: Within from weeks prior to esophagectomy, standardized MRI of the esophagus was performed in 15 patients (10 squamous-cell-carcinomas and 5 adenocarcinomas) using a 1.5 T whole body scanner. Imaging quality was classified based on depiction of aortic wall or tracheal wall layers. Criteria for malignant infiltration were a diameter of more than 15 mm or a round appearance of a lymph node together with GD-DTPA enhancement. All data were blinded and separately read by ...

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A 65-year-old woman who was diagnosed as having psoitis by CT findings, which disclosed non-symmetrical dilation of the psoas muscle and gaseous image. Pus from the psoas muscle seen at surgery corresponded to CT findings. Preoperative CT examination was useful in the establishment of diagnosis. (Namekawa, K.).

UK PubMed Central (United Kingdom)

Multimodality imaging with PET/CT and SPECT/CT has become commonplace in clinical practice and in preclinical and basic medical research. Do other combinations of imaging modalities have a similar...Full Text Available

UK PubMed Central (United Kingdom)

AIM: To improve the diagnosis of heterotopic pancreas by the use of contrast-enhanced computed tomography (CT) imaging and CT virtual endoscopy (CTVE).METHODS: A total of six patients with heterotopic...Full Text Available

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Purpose: To assess the new method of 3-dimensional echocardiography in comparison to the 'gold standard' MRI as to its ability to calculate left ventricular volumes in patients with congenital heart disease. Materials and methods: Eighteen patients between the ages of 3.9 to 37.3 years (mean: 12.8{+-}9.7) with a geometrically abnormal left ventricle were examined using a 1.5 T scanner with a fast gradient-echo sequence (TR=14 ms, TE=2.6-2.9 ms, FOV=300-400 mm, flip angle=20 , matrix=128:256, slice thickness=5 mm, retrospective gating) in multislice-multiphase technique. Transthoracic 3D-echocardiography was performed with a 3.5 MHz transducer and a Tomtec {sup trademark} (Munich, Germany) system for 3D reconstruction. Results: Volume calculation was possible in all patients with 3D-echocardiography, but the muscle mass calculation only succeeded in 11 to 18 patients (61%) due to inadequate visualization of the entire ...

British Library Electronic Table of Contents (United Kingdom)

This manuscript reviews some of the more controversial dose-related issues in cardiac CT imaging. Discussion covers the relative merits of cardiac CT versus MR, advantages and concerns regarding gated versus nongated cardiac CT and advantages and concerns regarding the use of breast shields in girls undergoing cardiac CT imaging.

UK PubMed Central (United Kingdom)

PurposeAuto-propagation of anatomical region-of-interests (ROIs) from the planning CT to daily CT is an essential step in image-guided adaptive radiotherapy. The...Full Text Available

UK PubMed Central (United Kingdom)

Low kVp settings provide high conspicuity of contrast materials at CT but may result in high image noise, particularly in larger patients. Material decomposition at dual energy CT can differentiate...Full Text Available

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Purpose: To evaluate contrast-enhanced CT scan in the diagnosis of intrahepatic cholangiocarcinoma by correlating the CT appearance with pathologic specimens. Materials and methods: Twenty-eight patients with pathologically proven intrahepatic cholangiocarcinoma were examined. Unenhanced abdominal CT study were performed in 28 patients; conventional contrast-enhanced CT in 27 patients. Enhanced CT scan including fast injection, fast scan and delayed scan at the largest section of the lesion was done in 7 patients. Contiguous 10 mm CT scans of the surgical specimens were also obtained in 8 patients. The preoperative and specimen CT scans in these 8 patients were compared with the corresponding pathological sections. A total of 103 areas of the pathological sections was compared with the CT appearances. Results: All ...

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70 patients with squamouscell carcinoma of larynx and hypopharynx were examined by computed tomography; the TNM staging of tumors by CT, by endoscopy and by surgical operation was reviewed. CT proved to be reliable both to recognize the presence of neoplasms, with the exception of those very superficial, and their deep spreading to preepiglottic and paralaryngeal spaces, to the soft tissues of the neck and to the cartilages. Therefore CT is the examination of choice in laryngeal neoplasms staging, because it precisely completes the clinical and endoscopical informations.

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Several recently introduced 'new' techniques in computed tomography - iterative reconstruction, gated cardiac CT, multiple-source, and dual-energy CT - actually date back to the early days of CT. We review the historic origins and evolution of these techniques, which may provide some insight into the latest innovations in commercial CT systems. (orig.)

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The CT colonography or virtual coloscopy is a new diagnostic method that allows the presentation of the whole colon using minimal invasive procedures. The method allows the detection of colorectal polyps and colorectal carcinomas. The book includes the following chapters: indications for CT colonography, diagnostic procedures, data processing and interpretation, diagnostic findings, preparation of the diagnostic result description and documentation, screening.

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The authors present a comparison between the diagnostic accuracy of Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) in the articular pathologies of the knee. CT and MRI were performed in 30 patients who subsequently underwent surgery. CT and MRI results were compared on three bases: technique, definition of normal anatomy, and diagnostic accuracy. CT allowed a standardization of the technique, while MRI was superior in defining normal anatomy - especially in the study of capsulo-ligamentous structures. In all cases the use of both CT and MRI allowed a correct diagnosis, showing the site, extent and gravity of the lesion. CT proved to be superior to MRI in 4 cases, while MRI corrected CT diagnosis in 11 cases; in 15 patients both techniques had the same diagnostic accuracy. Meniscal tears were better identified by ...

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Variation of CT units, in organs, before and after using contrast enhancing medium was reviewed and personal experience was presented. In the normal brain CT units was little changed by contrast enhancement (CE), whereas remarkable change was observed at lesions. No difference of CT units was observed between the normal liver and hepatomas. The normal kidney had higher CE effect than hypernephromas suggesting an increase of the sensitivity. CE was not found in cysts or necrosis. The changes of CT units in the cases of cerebral diseases are tabled with various contrast medium and scanners.

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In order to stress the role of computed tomography (CT) in the evaluation of benign spinal osteoblastoma, the authors examined by CT 10 patients with surgically and histologically proved osteoblastomas of the spine. Basing on surgical and histopathological findings CT proved to be a very important method for attesting the presence of the tumors (usually showed by radiographic examination), and specially for their staging and follow-up. CT in fact showed the real extent of the tumor into the spinal canal and towards the paraspinal soft tissues, and allowed the aerly detection of post surgical relapses. The authors conclude that CT is a primary diagnostic modality for preoperative planning and follow-up of benign osteoblastoma.

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A study on brain CT was made in 120 patients of human cysticercosis, which is a rare disease in Japan and clinical symptoms and laboratory data for the diagnosis were also discussed. From the point of therapeutic view, we proposed a new differentiation on brain CT of human cysticercosis, which is divided into two groups according to the alve or dead parasite. Furthermore, we proposed a new type named multiple large and small cysts type on brain CT. The idea of diagnostic standard was made integrating brain CT image, clinical symptoms and labolatory data. (author).

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CT-Expo is a novel MS Excel application for assessing the radiation doses delivered to patients undergoing CT examinations, based on computational methods that were used to analyze the data collected in the German survey on CT practice in 1999. The program enables the calculation of all dose quantities of practical value, such as axial dose free-in-air, weighted CTDI, dose-length product, effective dose and uterine dose. In contrast to existing programs for CT dose assessment, CT-Expo offers a number of unique features, such as gender-specific dose calculation for all age groups (adults, children, newborns), applicability to all existing scanner models including correction of scanner-specific influences, and the possibility of comparison with the results from the German CT survey on CT practice. Three different application modules offer free ...

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Lipiodol CT is a important modality for the diagnosis of hepatocellular carcinoma and compared is usually performed at 2-3 week after Lipiodol injection. Therefore, we assessed and the diagnostic value and merits of immediate CT after chemoembolization from there of 2-3 week delayed Lipiodol CT. Thirty three cases of chemoembolization which were performed both immediate CT after chemoembolization and 2-3 week delayed Lipiodol CT were reviewed retrospectively. They were divided into four grades according to pattern of lipiodol uptake by three radiologists. The diagnostic value of immediate Lipiodol CT was compared to delayed Lipiodol CT. Grade 0 was two cases(3.0%) and Grade 1 was seven cases(21.2%). In the cases of Grade 2(23/33, 69.7%), tumor uptake could be dishing wished from parenchymal uptake of Lipiodol by its density and pattern, ...

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CT-Expo is a novel MS Excel application for assessing the radiation doses delivered to patients undergoing CT examinations, based on computational methods that were used to analyze the data collected in the German survey on CT practice in 1999. The program enables the calculation of all dose quantities of practical value, such as axial dose free-in-air, weighted CTDI, dose-length product, effective dose and uterine dose. In contrast to existing programs for CT dose assessment, CT-Expo offers a number of unique features, such as gender-specific dose calculation for all age groups (adults, children, newborns), applicability to all existing scanner models including correction of scanner-specific influences, and the possibility of comparison with the results from the German CT survey on CT practice. Three different application modules offer free ...

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In a retrospective study of 21 patients, in whom the acetabular fractures were suspected on initial radiographs, we compared and analysed the computed tomographic findings and plain radiographic findings. The results were as follow: 1. In patients with multiple trauma, no further change in position was required during CT examinations. 2. CT showed intraarticular loose bodies, which were invisible on plain radiographs. 3. CT was useful in detecting the fractures of acetabular rims, medial wall of acetabulum, and femoral head. 4. CT permitted better evaluation of shape, extent, and degree of separation of fracture fragments. 5. CT was helpful in detecting the associated fractures and soft tissue injuries. 6. CT also demonstrated the adequacy of reduction, the position of metallic fixation devices, and the presence or absence of remaining intraarticular osseous ...

UK PubMed Central (United Kingdom)

Advances in laboratory animal imaging have provided new resources for noninvasive biomedical research. Among these technologies is microcomputed tomography (microCT) which is widely used to obtain high...Full Text Available

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In the Department of Radiology of Catholic University S. Cuore in Rome, a review was made of 342 CT examinations with a view towards optimizing the therapeutic planning in patients affected by bone metastases. All patients were submitted to radiological positioning and then to CT evaluation in order to assess the volume to be treated. In 224 cases it was not necessary to perform wide CT examination (3-5 standard tomograms being enough, 2 of which at the superior and inferior margins of the planned field). In the second group of 118 patients it was necessary to perform CT (serial axial scans) - increasing by 1-1.5 cm - up to the superior and inferior margins of the lesion. The existence of 2 types of lesions was confirmed: those involving mainly bony structures and those infiltrating the soft tissues. CT evaluation allowed the definition of the target volume to the real extension of ...

UK PubMed Central (United Kingdom)

Adaptive radiation therapy (ART) is the incorporation of daily images in the radiotherapy treatment process so that the treatment plan can be evaluated and modified to maximize the amount of radiation...Full Text Available

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Ten patients with suspected islet cell tumors (seven with possible gastrinomas, three with insulinomas) underwent diagnostic evaluation with dynamic CT scanning, routine CT scanning, angiography, and sonography. Venous sampling was also performed in selected instances. Nine sites of gastrinoma and three insulinomas were confirmed surgically in eight patients. Two patients had negative surgical explorations. Routine CT demonstrated five of the nine gastrinomas and one of two insulinomas. Angiography was positive in six of nine gastrinomas and all three insulinomas. Sonography showed only two of the nine gastrinomas and two of the three insulinomas. Dynamic CT scanning demonstrated three additional lesions (two gastrinomas, on insulinoma) not visible on routine CT scanning. Although most of these lesions were visible arteriographically, dynamic CT scans at the ...

UK PubMed Central (United Kingdom)

Objective. For the multislice CT (MSCT) systems with a larger number of detector rows, it is essential to employ dose-reduction techniques. As...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundThe purpose of our study was to evaluate the clinical value of hybrid SPECT/CT for the assessment of patients with painful total knee arthroplasty (TKA).MethodsTwenty-three...Full Text Available

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Twenty-five patients with ovarian carcinoma who had been operated and treated with chemotherapy underwent clinical examination and CT before reintervention (second-look laparotomy) to detect the presence of eventual recurrences. The prediction of recurrence based on CT and clinical findings was compared with the surgical findings at reintervention. CT proved to be more accurate than clinical examination in detecting recurrences; this was especially true for masses in the abdominal cavity, with the exception of small peritoneal nodules. The authors suggest the use of CT for staging the patients candidate to reintervention. This might help to avoid reintervantion in patients with persistent disease and to plan treatment.

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Positron emission tomography (PET) and X-ray computed tomography (CT) performed with PET/CT cameras allow us to obtain concurrently information on the presence and degree of alterations of myocardial perfusion and metabolism and on coronary arteries calcification. Furthermore, by gated myocardial perfusion studies, PET may provide crucial information on regional coronary blood flow reserve and endothelial dysfunction. A number of recent papers provide some insight on the potential of PET/CT in cardiology and in the assessment of various cardiovascular diseases including various types of vasculitis and metabolic diseases.

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Twenty rheumatoid arthritis (RA) patients with involvement of the cranio-cervical junction (CCJ) were given CT scan. In most cases the myelo-CT technique with the lumbar injection of small quantities of non-ionic contrast medium was adopted; CT easily diagnosed the horizontal and vertical dislocations on the CCJ, the bone strcture lesions and the inflammatory masses. A high frequency of medullary compressions was also found in these patients. Myelo-CT appears to be the technique of choice for the precise definition of the various factors responsible for the neurological complications found in RA of the CCJ.

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In Spiral CT, the pitch is the ratio of the distance to tabletop travels per 360 degrees rotation to nominal slice width, expressed in mm. Performing Spiral CT examination with pitch 2 allows to reduce examination time, exposure and contrast dose, and X-ray tube overload. The authors investigated the yield of pitch 2 in lung parenchyma studies, particular relative to diagnostic image quality.

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The experiences are described of the examination of orbita in children using computer tomography (CT). Over a period of four years 42 examinations were performed of children in the age ranging between 7 months and 15 years, i.e., 2.7 percent of all CT examinations performed. The highest diagnostic yield was in orbita tumours. The possibilities of CT are demonstrated on examples.

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As a self-teaching tool, this illustrated guide facilitates home study of the complexities of thoracic CT's. Over 400 illustrations and accompanying copy are used to provide a basis for understanding the CT appearances of disease processes and a comparison of CT lookalikes. It updates new and interesting developments in the format of case presentations.

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Ileal dysgenesis is an uncommon condition of unknown etiology occurring in the distal ileum in the region of the vitelline duct. The CT appearance of this lesion, although not previously described to our knowledge, is characteristic. We report a patient with ileal dysgenesis who had an abdominal CT scan to evaluate chronic iron deficiency anemia and protein-losing enteropathy. Recognition of this lesion by pediatric radiologists is important; so that surgical treatment, which is simple and effective, can be initiated quickly. (orig.)

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Chest computed tomography (CT) was valuable in detecting extrinsic tracheal compression by mediastinal masses in two pediatric patients. This prompted an independent evaluation by CT of 14 children with masses involving the middle mediastinum and possible intrathoracic tracheal narrowing. Computer programs permit precise calculation of tracheal cross-sectional areas. Any apparent decrease in tracheal area may be compared with CT-derived data in normal children. Chest CT not only demonstrates the presence of extrinsic airway compression in pediatric patients with mediastinal masses, but also is capable of precisely measuring the extent of this narrowing. This method identifies children at potential risk for respiratory compromise and may aid in subsequent therapy.

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Six patients with diskitis following lumbar disk surgery were investigated by Computed Tomography (CT). Four patients underwent CT in a rather early phase of the disease (5-37 days after the onset of the symptoms): a posterior paravertebral fluid collection was always recognized, while the plain film was normal. Later on (2-4 months), the classical signs of diskitis were evident, with both CT and the plain film. The collection was always present at CT. A reintervention, performed on 3 patients, revealed the purulent content of the collections. It seems reasonable to suggest a relationship between the collection and the subsequent diskitis; the collection is probably an early sign of the disease. Its detection is of grat value, because it could allow an immediate and adequate therapy. The authors stress the usefulness of performing CT in an early phase on this kind of symptomatic ...

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The two main aspects of the concept proposed by the ICRP in recommendation 26 for the radiation risk, the differentiation of stochastic and non stochastic damages and the qualification of the stochastic risk, are discussed in its consequences for radiation protection in X-ray diagnostics. Quantitative results from the literature serve to demonstrate the risk factors for the various organs and their sum concerning the position of the layer. As special points of somatic risk appeared the mamma and the pelvic region. The particular risk of CT examination is determined by number and position of the layers and the scan parameters of the system. For typical CT examination the resulting risk factors are estimated in comparison with conventional X-ray diagnostics. The somatic risk of CT examination is relatively high and comparable to conventional examination with the highest risk, while the genetic risk - as in conventional ...

International Nuclear Information System (INIS)

The two main aspects of the concept proposed by the ICRP in recommendation 26 for the radiation risk, the differentiation of stochastic and non stochastic damages and the qualification of the stochastic risk, are discussed in its consequences for radiation protection in X-ray diagnostics. Quantitative results from the literature serve to demonstrate the risk factors for the various organs and their sum concerning the position of the layer. As special points of somatic risk appeared the mamma and the pelvic region. The particular risk of CT examination is determined by number and position of the layers and the scan parameters of the system. For typical CT examination the resulting risk factors are estimated in comparison with conventional X-ray diagnostics. The somatic risk of CT examination is relatively high and comparable to conventional examination with the highest risk, while the genetic risk - as in conventional ...

International Nuclear Information System (INIS)

There are many differences between industrial CT and industrial radiography, such as imaging principle, inspection time, radiation dose and the requirements for operators etc. The national standards for radiation protection of industrial detection are not applicable to the requirements of protection and safety for #gamma#-ray industrial CT to some extent now. In order to standardize the production and use for #gamma#-ray industrial CT, protect the safety of operators and the public, and to promote the popularization and application of #gamma#-ray industrial CT, it is significant to establish the national standards for radiation protection of #gamma#-ray industrial CT as soon as possible. The purpose of this paper is to introduce the contents of this standard, and specify some important terms. Then there is a brief discussion on the existing problems during establishing such ...

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The growth of a middle ear cholesteatoma behind a normal tympanic membrane is a rate though possible event. In such cases, CT may provide useful information for diagnosis. The results are presented of a CT study carried out on 14 patients affected with unilateral conductive hearing loss and with normal tympanic membrane. CT allowed the diagnosis of meddle ear cholesteatoma to be made in all cases. All patients were treated with surgery: 8 of them underwent tympanoplasty and 6 explorative tympanotomy. While the diagnosis of cholesteatoma was confirmed in 13 patients, in 1 case tympanosclerosis was diagnosed. CT diagnosis of middle ear cholesteatoma is based on the demonstration of a low-density soft-tissue mass, in association with bone erosion or ossicular dislocation. The author emphasizes the difficulty of a CT diagnosis of cholesteatoma in the patients with middle ear soft-tissue ...

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The enhancements described of high-performance CT systems of latest design have again confirmed the importance of CT systems for acute and selective diagnostic imaging. Higher availability, shorter exposure times, and better applicability and handling for examination of poly-traumata patients or patients of intensive care departments are some of the advantages achieved with CT systems which demonstrate CT system efficiency in addition to MRI, which for specific examinations will remain the modality of first choice for diagnostic evaluation. The Tomoscan Av-E presented here was able to answer all relevant diagnostic questions appearing in routine diagnostics and scientific work. For patients, examinations using the spiral CT technique also offers significant advantages. (orig./CB) [Deutsch] Durch die dargestellten Verbesserungen bei Hochleistungs-CT-Systemen ...

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Purpose: To evaluate micro computed tomography (micro-CT) for the assessment of osteochondritis dissecans in comparison with histology. Material and Methods: Osteochondritis dissecans lesions of 3 patients were evaluated using micro-CT (0.125 mA, 40 keV, 60 m slice thickness, 60 m isotropic resolution, entire sample) and light microscopy (toluidine blue, 3-5 m slice thickness). The methods were compared regarding preparation time, detectability of tissue types and morphologic features of bone and cartilage. Results: Non-destructive micro-CT imaging of the entire sample was faster than histologic preparation of a single slice for light microscopy. Morphologic features of bone and cartilage could be imaged in a comparable way to histology. It was not possible to image cells or different tissue types of bone and cartilage with micro-CT. Conclusion: Micro-CT is a fast, non-destructive ...

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In a prospective study, 58 patients with carcinomas of the bladder were examined by CT and MRI; in 48, gadolinium-DTPA was administered intravenously. MRI provided exact staging in 89%, compared with 80% with CT. There was 13% over-staging with CT and 11% with MRI. MRI, unlike CT did not result in any under-staging. In 36 patients a quotient could be calculated from the signal intensity of the tumour and surrounding soft tissues both before and after the intravenous contrast medium and the increased quotient after contrast administration could be estimated. There was a significant increase in the tumour/muscle quotient with a mean of 72#+-#22% (minimum 43%, maximum 153%), corresponding to a marked increase of the signal form the tumour when compared with the precontrast images. This had the following advantages compared with CT: Accurate differentiation between superficial and ...

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Purpose: To determine the value of MRI in the preoperative evaluation of chronic paranasal sinusitis and to compare the results with CT and intraoperative findings. Method/Materials: 42 patients with clinical signs of chronic paranasal sinusitis underwent MRI after CT evaluation on one day, with subsequent functional endoscopic sinus surgery on the next day. Coronary CT was obtained with 5-mm slices and table-feed in the prone position, while MRI was performed in the supine position with coronary T_2-TSE+pd and coronary and transverse HASTE, each with 5-mm slice thickness. Aquisition time in MRI was less than 8 minutes. Two radiologists reviewed the CT and MRI scans for signs of sinusitis and detection of anatomical landmarks. The results were correlated with the intraoperative findings. Results: MRI offered no artifacts of dental work and showed more often high quality pictures than ...

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Purpose: To describe CT appearances in patients with unilateral cleft lip and palate (CLP) 20 years after bone graft surgery. Material and Methods: Eighteen consecutive patients with unilateral CLP were examined. All patients had been treated with primary closure, both in infancy and early childhood, supplemented with bone grafting at the age of around 10 years. The CT examination of the upper jaw included a dental CT program. The CT appearances of the cleft side were compared with those of the untreated non-cleft side. Results: Abnormal CT appearances included skew nasal aperture (n=17), nasal septal deviation (n=17), low floor of nasal aperture (n=15) at or towards the cleft side, and deviation of anterior nasal spine towards the non-cleft side (n=18). The posterior part of the bone cleft was visible in all patients, and the dental arch was V-shaped in 8. Conclusion: Although ...

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The main purpose of this work is to report the personal experience with addition of contrast-enhanced multiphase helical CT to unenhanced CT (Lipiodol CT) in the evaluation of patients with hepatocellular carcinoma treated with chemoembolization and to analyze the present role of oily agent CT. It has been retrospectively reviewed the examinations of 42 consecutive patients submitted to globla chemoembolization over a 2-year period. CT was performed 18-30 days after the treatment. The Lipiodol CT study was carried out with volume acquisitions. It has been considered as nodules all well-defined areas with dense oily agent uptake; uptake itself was classified as: 0=absent, I=lower tha 10% of the tumor volume; II=lower than 50%, III=50%, IV=homogeneous. Contrast-enhanced helical CT was performed with the 2-phase technique in 28 patients and ...

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To evaluate the role of positron emission tomography-computed tomography (PET-CT) in staging and determining early treatment response to chemotherapy in children with neuroblastoma (NB) and its correlation with the final outcome. Patients and Methods: Seventeen patients of NB with mean age of 51.5 months (age range 2-132 months; 14 males, 3 females) underwent serial "1"8F-fluorodeoxyglucose (FDG) PET-CT imaging. All 17 patients were for staging before any treatment. Twelve of 17 patients underwent "1"3"1I meta-iodobezylguanidine (MIBG) scan and bone scan. MIBG uptake was seen in the primary lesion in 11/12 patients. MIBG uptake in bones was seen in 3/12 patients. All bone lesions were concordant on MIBG and bone scan. Early response to chemotherapy was evaluated after two cycles using PET-CT. A 30% reduction in longest diameter was taken as cut-off value for response on CT based on the response ...

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Thirty-five patients with temporal bone fractures were examined; the fractures were sometimes associated with dislocation of the assicular chain caused by road fatalities. Computed Tomography (CT) was performed either because of the presence of clinical symptoms associated with trauma of the temporal bone, because of a hemotympanum discovered during a CT scan of the brain. Thirty-three fractures were detected: 19 longitudinal, 6 transverse, and 8 complex. An incudostapedial dislocation was also detected, together with a displacement of a stapedial prosthesis from the lenticular process of incus, and 3 incus-malleus dislocation associated with fractures. High resolution CT allows the precise definition of the course of the fractures, of the associated dislocation of the ossicular chain, and of facial nerve lesion, thus allowing a more accurate surgical intervention. In the examination of the temporal bone, high resolution ...

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CT scans were performed on 25 patients suspected of sustaining ranal trauma. The utility of CT in both detecting renal damage and appraising the gravity of injuries was assessed. Nowadays, in fact, nephrectomy or reserved for lesions devastanting the kidney parenchyma or rupturing the renal pedicle; so it is very important to identyfy both the purposes of a better planned therapeutic approach. CT does both, being more accurate than urography in the detection of renal fractures, intra or extraparenchymal hematomas and contrast media extravasation. Urography very often shows aspecific lesion patterns and sometimes it is also falsely negative. In the present series CT was more reliable than angiography itself, particulary in the diagnosis of extra-renal hematic collections, contrast media extravasation and injuries to the other abdominal organs. Although CT may arouse the suspicion of ...

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This study was aimed at evaluating CT sensitivity in identifying the signs of pulmonary cystic fibrosis (CF). The chests of 39 patients (16 males and 23 females, mean age 19.1 years) were examined by CT: all patients had been given a clinical score according to Schwachman and Kulckzycki criteria. Thickened bronchial walls were observed in all cases, which are typical of peribronchitis. Bronchiectases were present in 87% of cases; their extent, pattern and localization were exactly shown on CT scans. Bronchoceles were seen on CT scans in 64% of patients; less frequent was the finding of atelectases and subpleural bullous emphysema. In a great number of patients (64% and 82%, respectively) pleural thickening and hilar adenopathy were demonstrated on CT scans. In conclusion, our results confirm CT as a more sensitive method than conventional radiography to identify ...

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Snapping or grating scapula is a condition of the shoulder girdle in which the patient complains of pain and an audible snapping sound which may be associated with pain. We evaluated the diagnostic value of the computed tomography (CT) scans using the clinical diagnosis of a grating scapula as the gold standard. This retrospective study reports the sensitivity, specificity, likelihood ratio and receiver operator characteristic curve for the CT scans and the k value as a measure of the interobserver agreement. None of the parameters validated the examination. We therefore concluded that CT scans are inappropriate for differentiation between a grating scapula and a normally functioning shoulder except in cases where bony abnormalities are present. (orig.)

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Twenty-seven patients with symptoms or clinical findings suggesting joint or bone disorders of the anterior chest wall (ACW) were evaluated by spiral CT with 3-dimensional (3-D) and multiplanar reconstructions. Preceding conventional ACW tomography was performed in 10 patients. ACW joint and bone changes were visualized more adequately by coronal 2-D reconstructions based on spiral CT than by conventional tomography. In addition, nonossified costal cartilages and soft tissue lesions were demonstrated. 3-D reconstructions sometimes added information, especially in patients with fracture and dislocation. (orig.).

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The value of CT in respect of preoperative determination of tumour status and of tumour classification was studied using 127 histologically identified ovarial tumours as basis in a blind study via mutual image classification by the two participating institutes. The medium accuracy of diagnosis was 82%, but the results were found to be greatly dependent on tumour histology. Quotas of more than 90% were obtained in case of functional cysts, cystomas, cystadeno-carcinomas and dermoids, whereas classification was less successful with the other types of tumours such as germ cell tumours, tumours of the sexually differentiated stroma, metastases and tubo-ovarial abscesses.

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The main purpose of this paper is to stress the importance of CT depiction of the mandibular incisive canal. This anatomical structure contains a major neurovascular bundle and is thus very important in the planning of mandibular implants in the canine-incisive area. The importance of careful assessment of the mandibular canal course before implantology is now widely recognized. The same holds true for the canine-incisive region in the jaw, to detect the incisive canal if present and prevent any complications from its accidental damage. CT with a dedicated software showed the incisive canal in a large number of patients, which calls for precise reporting of its presence, course, and relationships with teeth.

British Library Electronic Table of Contents (United Kingdom)

Objectives Clinical PET/MR requires the use of patient positioning aids to immobilize and support patients for the duration of the combined examination. Ancillary immobilization devices contribute to overall attenuation of the PET signal, but are not detected with conventional MR sequences and, hence, are ignored in standard MR-based attenuation correction (MR-AC). We report on the quantitative effect of not accounting for the attenuation of patient positioning aids in combined PET/MR imaging. Methods We used phantom and patient data acquired with positioning aids on a PET/CT scanner (Biograph 16, HI-REZ) to mimic PET/MR imaging conditions. Reference CT-based attenuation maps were generated from measured (original) CT transmission images (origCT-AC). We also created MR-like attenuation map...

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Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired disease involving multiple hematopoietic cell lines. Characteristics of PNH are intrinsic hemolytic anemia, iron deficiency anemia and venous thrombosis. We report a case of PNH with characterostoc MR and CT findings. The signal intensity of renal cortex was lower than that of medulla on both T1-and T2-weighted MR imaging. On T2 weighted MR images, the liver showed very low signal intensity but the signal intensity of the spleen was normal. On precontrast CT the attenuation of renal cortex was higher than that of renal medulla and the attenuation of liver was higher than that of the spleen. These findings of MR imaging and CT were the result from the deposition of hemosiderin in the cells of proximal convoluted tubules and transfusional hemosiderosis of liver.

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1980. p. 94. Bulgaria Stargardt, A. Institut fuer Roentgendiagnostik, Charite,

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It is often necessary to estimate the dose of radiation to a fetus from a series of CT scans. To assist in making this process easier and more accurate, we measured fetal doses in an adult anthropomorphic phantom for four CT scanners: Picker 1200, Siemens DRH, GE 9800, and GE 8800. Measurements were made at four kilovoltages (100, 120, 130, and 140 kVp), for 2-, 5-, 8-, and 10-mm thicknesses, for two scanning angles (360 degrees and 398 degrees) and for two patient orientations (prone and supine). The fetal-dose estimates are based on the CT dose index measured by using a pencil ionization chamber at the center position of a 16-cm-diameter cylindrical phantom. Comparison with data from other investigators shows reasonable agreement when phantom differences, X-ray tube output, and equipment calibration are considered.

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Bowel infarction is a rare and typical condition of the elderly; despite improvements in diagnostic imaging and vascular surgery, bowel infarction remains a major cause of acute abdomen, with mortality rates ranging 70-80%. Diagnosis on often late because clinical sings, laboratory data and radiologic findings are a specific. The authors investigated radiographic and particular CT patterns of intestinal infraction in 56 patients submitted to surgery within 12 hours of admission. We also report the CT findings of 5 of these patients who had reversible mesenteric ischemia. CT is more sensitive than radiography and does not exhibit the limitations of angiography (i.e., invasiveness, radiation exposure an complex organization. Therefore CT can presently be considered the method of choice in patients with suspected bowel infarction.

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The evaluate the signs of aortic intramural hematoma with helical CT and the diagnostic role of this technique in patients with this condition. It was reviewed the CT findings of 396 patients submitted to emergency examinations for suspected aortic dissection from 1995 to 1999. Only 18 patients (6 women and 12 men) had CT signs of aortic intramural hematoma. Helical CT studies were carried out with the following parameters: slice thickness 10 mm, reconstruction index 10, feed 1.5 mm, conventional algorithm with minimum values of 130 kV and 125mA. All patients were examined with dynamic contrast-enhanced CT, before and after a power injection of 130 mL ionic contrast material. It was studied: hematoma localization and longitudinal extension; thickness and density of aortic wall; presence and location of intimal calcifications; integrity of intimal wall; hemo mediastinum and/or hemo ...

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To assess the variability and systematic differences in polyp measurements on optical colonoscopy and CT colonography. Gastroenterologists measured 51 polyps by visual estimation, forceps comparison and linear probe. CT colonography observers randomly assessed polyp size two-dimensionally (abdominal and intermediate window) and three-dimensionally (manually and semi-automatically). Linear mixed models were used to assess the variability and systematic differences between CT colonography and optical colonoscopy techniques. The variability of forceps and linear probe measurements was comparable and both showed less variability than measurement by visual assessment. Measurements by linear probe were 0.7 mm smaller than measurements by visual assessment or by forceps. The variability of all CT colonography techniques was lower than for measurements by forceps or visual assessment and sometimes lower (only ...

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The introduction of CT scan and, more recently, magnetic resonance imaging, has radically changed the diagnostic approach to tumors developed in the internal auditory canal and cerebellopontine angle. CT scan with intravenous injection visualizes tumors lying in the cerebellopontine angle. Magnetic resonance imaging, especially using gadolinium, is a very accurate means for diagnosing tumors of both the auditory canal and cerebellopontine angle.

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(1) To determine the accuracy of computed tomography (CT) in the evaluation of ligament tear and avulsion in patients with tibial plateau fracture. (2) To evaluate whether the presence or severity of fracture gap and articular depression can predict meniscal injury. A fellowship-trained musculoskeletal radiologist retrospectively reviewed knee CT and MRI examinations of 41 consecutive patients presenting to a level 1 trauma center with tibial plateau fractures. Fracture gap, articular depression, ligament tear and footprint avulsions were assessed on CT examinations. The MRI studies were examined for osseous and soft tissue injuries, including meniscal tear, meniscal displacement, ligament tear, and ligament avulsion. CT demonstrated torn ligaments with 80% sensitivity and 98% specificity. Only 2% of ligaments deemed intact on careful CT evaluation had partial or complete tears on ...

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Primary peritoneal malignant mixed mullerian tumors are very rare. We report the case of a patient presenting with pain in the right upper quadrant of the abdomen and in whom the physical examination demonstrated a peritoneal mass. Computed tomography (CT) confirmed the presence of a mass, with invasion of adjacent organs.

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Objective was to assess the accuracy of a single versus combined use of ultrasound (US) or computed tomography (CT) in the localization of diseased parathyroid glands. Forty-one patients with hyper-parathyroidism treated surgically between January 2000 to December 2005 at Jordan University Hospital, Amman, Jordan were included in this study. Preoperative ultrasonographic and CT findings were reviewed and compared to the intraoperative and pathologic diagnosis of diseased parathyroid glands. The mean age of patients was 46 years (range 16-70; 15 males and 26 females). Parathyroid adenoma was confirmed in 33 patients and hyperplasia of the parathyroid glands in 8 patients. Preoperative evaluation was carried out in 32 patients (CT scan) and in 23 patients (US). In 18 cases, the diagnosis of parathyroid disease was based on CT findings alone and in 9 patients the diagnosis was based on a single US finding. ...

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Differentiating a benign from a malignant lesion by information such as density data, or signal intensities or echo gradients, is not possible with CT, nor MRI, nor ultrasonography. Only some lesions show characteristic signs. Inflammations cannot be difscriminated from malignant tumors. CTs of small tumors in particular are so poor in contrast that it is much more difficult to detect tumors or discriminate them from other lesions, as compared to MR images or ultrasonographs. CT does not detect surface tumors, but is more sensitive than MRI or US in detecting discrete cortical bone lesions. The same applies to small calcified tumors. MRI however is most sensitive in detecting tumor volumes in the yellow marrow, and is the best modality for evaluation of extraossal extension of tumors. CT yields better results than MRI if applied for simultaneous screening of lymph node metastases in the lower neck. MRI frequently is spoilt ...

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Purpose: The aim of this study was to demonstrate the typical appearance of ganglioneuromas in computer-assisted tomography (CT), and magnetic resonance imaging (MRI). Material and methods: Retrospective analysis of diagnostic imaging (9 CT, 6 MRI) in 9 children aged 3 to 15 years with the histological diagnosis of ganglioneuroma. Results: The tomographies showed large (max. 13.4 cm in diameter) round or oval tumors with sharp delineation. The sites of the tumors were the retroperitoneum (5), the mediastinum (3), and the adrenal gland (1). Intraspinal tumor involvement occurred in 4 cases. On comparing CT with MRI, MRI was more accurate in defining the intraspinal involvement. The ganglioneuromas were of hypodense appearance in the native CT scan and showed moderate enhancement upon administration of contrast media. In five patients tumor calcifications with a disseminated sprinkled pattern were seen in ...

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Differentiating a benign from a malignant lesion by information such as density data, or signal intensities or echo gradients, is not possible with CT, nor MRI, nor ultrasonography. Only some lesions show characteristic signs. Inflammations cannot be difscriminated from malignant tumors. CTs of small tumors in particular are so poor in contrast that it is much more difficult to detect tumors or discriminate them from other lesions, as compared to MR images or ultrasonographs. CT does not detect surface tumors, but is more sensitive than MRI or US in detecting discrete cortical bone lesions. The same applies to small calcified tumors. MRI however is most sensitive in detecting tumor volumes in the yellow marrow, and is the best modality for evaluation of extraossal extension of tumors. CT yields better results than MRI if applied for simultaneous screening of lymph node metastases in the lower neck. MRI frequently is spoilt ...

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We used computerized tomography (CT) in the study of eight patients with macronodular splenic tuberculosis prior to the microbiological diagnosis. These patients underwent additional CT controls during and after tuberculostatic therapy. All the patients studed presented the acquired immunodeficiency syndrome (AIDS). Splenomegaly and numerosous round, hypodense lesions that showed no contrast uptake were found in all the subjects. Only three patients presented evidence of tuberculosis in plain radiography and/or chest X-ray. Two patients presented abdominal lymph nodes. None of them showed evidence of hepatic lesions or ascites. follow-up CT scans revealed a progressive reduction of the lesions, which eventually disappeared completely, and splenomegaly was considerably reduced. Anthough it is uncommon, we should suspect splenic involvement in tuberculosis if the clinical and radiological contexts are appropriate. ...

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The dose distribution in a Rando phantom has been measured for typical EMI 5005 CT scans of the head, chest, abdomen and pelvis. These dose distributions have been used to generate quantitative estimates of the somatic and genetic radiation risks associated with these CT examinations and also to measure the total energy imparted during each scan. A comparison has been made between the radiation risk estimates and the energy imparted measurements. The energy imparted measurements are not a good indicator of the somatic and/or genetic risks when one type of CT scan is compared with another. However, for a given type of scan, the energy imparted may be a reasonable indicator of the relative somatic risks associated with different CT examinations. Considerable care should be taken when interpreting and using any measured value of energy imparted in a radiological examination since published values of the ...

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In less than a decade computed tomography (CT scanning) had a profound impact on diagnostic radiology. Radiology of the orbit is no exception. As early as 1973, reports published in the radiological literature indicated that this new noninvasive imaging method was a highly effective way of demonstrating intraorbital mass lesions. As CT scanners became widely available, computed tomography became a significant adjunct to ophthalmological diagnosis. Today the main indications for CT scanning of the orbit are: (1) suspected mass lesions, most frequently presenting as exophthalmos, (2) orbital trauma, including foreign bodies, (3) some congenital anomalies, and (4) suspicion of extension into the orbit of extraorbital disease processes. Along with ultrasonography, another new noninvasive imaging technique, CT has replaced a number of more invasive and often less effective diagnostic methods, such as orbital ...

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Background. A change in practice at our institution resulted in increased use of anesthesia for CT scan of the chest in children who required sedation. Objective. To determine whether there is a difference in the frequency or severity of pulmonary atelectasis on CT scan in children sedated by anesthesiologists compared with children sedated by radiologists using intravenous pentobarbital. Materials and methods. Retrospective blinded review of 60 CT scans of the chest performed in 41 children. Forty-one studies in children sedated by radiologists (median age 29 months) were compared with 19 studies in children sedated by anesthesiologists (median age 25 months). Results. Atelectasis sufficient to obscure pulmonary metastases was shown in 5 of 41 (12 %) radiology sedations and 13 of 19 (68 %) anesthesiology sedations (P < 0.01). Higher grades of atelectasis were recorded in children under anesthesia (P < 0.01). ...

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We investigated the efficacy of combined FDG-PET/CT imaging for the diagnosis of small-size uveal melanomas and the feasibility of combining separate, high-resolution (HR) FDG-PET with MRI for its improved localization and detection. Patients, methods: 3 patients with small-size uveal melanomas (0.2-1.5 ml) were imaged on a combined whole-body PET/CT, a HR brain-PET, and a 1.5 T MRI. Static, contrast-enhanced FDG-PET/CT imaging was performed of head and torso with CT contrast enhancement. HR PET imaging was performed in dynamic mode 0-180 min post-injection of FDG. MRI imaging was performed using a high-resolution small-loop-coil placed over the eye in question with T2-3D-TSE and T1-3D-SE with 18 ml Gd-contrast. Patients had their eyes shaded during the scans. Lesion visibility on high-resolution FDGPET images was graded for confidence: 1: none, 2: suggestive, 3: clear. Mean tumour activity was ...

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Purpose: Evaluation of the diagnostic efficacy and cost-benefit of contrast enhanced CT (CT) and MRI pre- and post-SPIO-particles in focal hepatic disease with consideration of therapeutic outcome. Results: In 34/52 (65.4%) of the cases the correct diagnosis was primarily stated by CT (sensitivity [se.] 85.2%, specificity [sp.] 44.0%). In additional 10/52 of the cases unenhanced MRI (se. 91.4%, sp. 75.0%) enabled correct diagnoses, and in another 6 cases the diagnosis was established only by SPIO-MRI (se. 100%, sp. 86.7%). Considering the possible therapeutic recommendation arising from each modality, CT would have induced needless therapy costs of 191,042 DM, unenhanced MRI of 171,035 DM, and SPIO-MRI of 7,311 DM. In comparison to the real therapy costs of 221,873 DM, this would have corresponded to an unnecessary increase of therapy costs of 86.1%, 77.1%, and 3.3%, respectively. In two cases (91 ...

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Technical innovations such as the availability of movable patient platforms and the introduction of 32-channel systems have made whole-body MRI for tumor staging feasible. In addition, the development of dual-modality PET/CT systems offers the opportunity to perform anatometabolic tumor staging with whole-body coverage in a single session. Based on an increase in patient survival when applying a stage-adapted therapy in different malignant diseases the relevant question relates to the accuracies of whole-body MRI and whole-body PET/CT for TNM staging. This review article addresses whole-body tumor staging with MRI and FDG-PET/CT with special emphasis on diagnostic accuracies for staging different malignant diseases. (orig.) [German] Technische Neuerungen, wie die Verfuegbarkeit beweglicher Tischaufsaetze oder die Einfuehrung von 32-Kanal-Systemen, haben die Ganzkoerperbildgebung mit der MRT ermoeglicht. Die Entwicklung ...

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Our objective was to evaluate the feasibility of ultra-low-dose scanning for multislice CT colonography in the detection of colorectal lesions. Twenty-seven patients (14 men, 13 women) with clinical indication for conventional colonoscopy were recruited. Multislice spiral CT (Somatom Plus 4 Volume Zoom, Siemens, Germany) examinations were performed after standard oral colonoscopic preparation and colonic distension with room air. Images were acquired using 2.5-mm collimation, 3.0-mm slice thickness, standard reconstruction kernel, 140 kVp, and 10 mAs. Supine and prone acquisitions were obtained in all patients. Images were analyzed on a workstation by two gastrointestinal radiologists. Conventional colonoscopy was performed on the same day in all patients and represented the standard of reference. Total radiation exposure was also calculated. All colorectal cancers were correctly identified at CT colonography (9 of 9, ...

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Each disease affecting the bile ducts tends to produce characteristic pattern of biliary dilatation: recurrent pyogenic cholangitis causes dilatation and straightening of the larger (central) intrahepatic ducts: clonorchiasis causes dilatation of the smaller (peripheral) intrahepatic ducts; and carcinoma along the extrahepatic ducts causes (proportional) dilatation and tortuosity of both larger and smaller intrahepatic ducts. To evaluate the specificity of the pattern and morphology of the dilated biliary tree on CT scans (CT characterization) three independent radiologists who were unifamiliar with the cases were asked to classify 62 CT scans in patients with obstructive jaundice. The case population consisted of 14 cases with recurrent pyogenic cholangitis, 18 cases with clonorchiasis and 30 cases with carcinoma along the extrahepatic ducts, which were intermixed randomly. Classification was made only on the basis of ...

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Free form fabrication and high resolution imaging techniques enable the creation of biomimetic tissue engineering scaffolds. A 3D CAD model of canine trabecular bone was produced via micro CT and exported to a fused deposition modeler, to produce polybutylene terephthalate (PBT) trabeculated scaffolds and four other scaffold groups of varying pore structures. The five scaffold groups were divided into subgroups (n=6) and compression tested at two load rates (49?N/s and 294?N/s). Two groups were soaked in a 25??C saline solution for 7?days before compression testing. Micro CT was used to compare porosity, connectivity density, and trabecular separation of each scaffold type to a canine trabecular bone sample. At 49?N/s the dry trabecular scaffolds had a compressive stiffness of 4.94?1.19?MP...

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MRI findings in 13 patients with monolateral parotid tumor were compared with US, sialographic and CT findings. MRI did not allow an accurate diagnosis in 2 patients with diffuse chronic parotitis. MRI was superior to CT in 1 case in defining the intraglandular site of the lesion, and in 2 patients in showing the extraglandular involvement. MRI proved to be superior to CT thanks to its contrast resolution and to multiplanar imaging. MRI high contrast resolution made it possible to demonstrate neoplastic lesions of 4 mm in diameter. The lesion has low signal intensity on T1-weighted images and high signal intensity on T2-weighted. Parotid tumors cannot be characterized by signal intensity alone: only morphology allows to discriminate between benign and malignant lesions. To conclude, US is a screening method, while MRI is helpful in detecting multifocal lesions and in evaluating the tumor extent.

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Dynamic CT and MRT were performed in 21 patients who had undergone prosthetic replacement of the aorta because of dissection of the thoracic aorta. There is no difference between MRI and dynamic CT in the demonstration of a persistent intimal flap, the formation of a thrombus and the assessment of the aortic diameter in patients who underwent surgery for thoraco-abdominal aortic dissection. MRI, however, is superior in the identification of the true and false lumen and the demonstration of the distal anastomotic site. The major advantages of MRI are that there is no need for intravenous contrast agents, that it is high sensitive to flow phenomena, and that it can demonstrate the aortic arch and the ascending aorta on sagittal oblique sections. The major disadvantages of MRI are the limited access to the patient during the procedure, and the inability to examine patients fitted with pacemakers or who are on assisted ventilation. Today, MRI is ...

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CT findings were compared retrospectively between 9 cases with malignant lymphoma of the anterior mediastinum and 8 cases with invasive thymoma. CT findings of malignant lymphoma were as follows: (1) The majority of the tumors were bilateral and extended beyond the anterior mediastinum to the other mediastinum compartments. (2) Their margin was either smooth or lobulated. (3) Their density was either homogeneous or heterogeneous. In the case with heterogeneous density, ring, triangle and/or band-like low density areas, just like interspace of fused lymph nodes, were demonstrated. Calcification or cysts could not be shown. (4) Patent inherent vessels without deviation were occasionally demonstrated running through the tumors. (5) The tumors faced and contacted widely to anterior chest wall and often pressed the lung laterally at the anterior parietomediastinal pleural reflection. (6) Pleural implants were not demonstrated. (author).

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Bone mineral content as determined by computerized tomography (CT) and mechanical strength on axial loading were compared in 36 cadaveric femur specimens. Based on the CT measurements of density and area, the mass of a transverse slice of the femur was estimated. Highly significant correlations were demonstrated between strength and cancellous bone density. Even higher correlations were revealed when the bone masses of the proximal and distal femoral areas were calculated. Based on these findings, an equal distribution of the effective mass of the femur was postulated. This hypothesis was confirmed in an experimental rotational model. The CT attenuation values were also correlated to direct measurements of bone mineral content, i.e. calcium. Moreover, the strength of different metal implants, commonly used in femoral neck fractures, were assessed in cadaver specimens. 134 refs., 13 figs., 12 tabs.

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A prospective comparative study with pathology was performed to assess the clinical value of Computed Tomography (CT) and endoscopic ultrasound (EUS) for nodal staging in lung cancer. A total of 329 nodal stations were dissected or sampled and 755 lymph nodes were examined at histology. On a pre-station basis, CT had greater sensitivity (74%) than EUS (56%), but EUS was more specific (83% versus 93%). The accuracy rates of the two techniques were similar. In conclusion, endoscopic ultrasound should be part of a routine preoperative diagnostic approach to non-small-cell lung cancer., because of its high specificity. Results can be improved when EUS and CT are combined., which suggests that these imaging modalities should be used together in selected patients for the noninvasive staging of non-small-cell lung cancer to identify local lymphatic spread.

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Tridimensional localization of bone and soft tissue injuries in complex facial trauma is fundamental for treatment. The face can be conceptualized as 3 groups of interconnected osseous struts that are oriented in the horizontal, sagittal and coronal planes. Each group of struts is closely related to specific soft tissue structures that are susceptible to injury. Any single CT section in the coronal plane or in the axial plane contains parts of one or more these struts. Facial CT in biplane were performed in 32 patients of facial trauma. The most common site of facial fractures is found in middle part of horizontal struts, geometrically in anteromedial portion of the inferior orbital fissure of the face. The most common soft tissue injury combined with facial fracture is hematoma and/or herniated orbital contents into the maxillary sinus. The serious combined soft tissue injuries were ocular rupture, retroorbital hematoma and optic nerve injury ...

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... CT angiograph for the peripheral rteries. a beautiful 3D-vision on the structures inside e chest. Okay. ... have an angled camera here. This is a 3D camera, and the surgeon has got th What ...

UK PubMed Central (United Kingdom)

Four-dimensional (4D) radiotherapy is the explicit inclusion of the temporal changes in anatomy during the imaging, planning, and delivery of radiotherapy. One key component of 4D radiotherapy planning...Full Text Available

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W. Wayne Scott. ABSTRClCT. Primary proton and secondary particle doses (both .... W. Wayne Scott and R. G. Alsmiller, Jr., Comparisons of Results Ob- ...

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The MRI and CT appearances in 48 patients with histologically confirmed benign and malignant pleural abnormalities were compared retrospectively. Abnormal pleural changes were shown in 47 out of the 48 patients by high signal intensity of the pleura in T_2-weighted sequences and in contrast enhanced T_1-weighted sequences on MRI. CT showed abnormalities in 45 out of 48 patients. Delineation of pleural and pulmonary changes by CT was possible in 13 out of 23 cases, and pleural disease from effusions in 15 out of 28 cases. T_2-weighted MRI was successful in 14 out of 23 and 4 out of 28 cases, respectively. T_1-weighted images after contrast were successful in 20 out of 23 and 22 out of 28 cases, respectively. Indications of malignant pleural disease were the presence of mediastinal or circumferential involvement or involvement of the entire pleura, thickness of more than 10 mm and nodular changes. The most reliable sign of ...

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BackgroundCavernous hemangiomas are the most frequent neoplasms of the liver and in routine clinical practice they often need to be differentiated from malignant tumors and other...Full Text Available

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Correct ortopedic therapy for traumas of the cervical rachis requires perfect knowledge of the spatial balance of the fracture focus. The authors belive Computed Tomography (CT) to be the most suitable, and often indispensable, method for this purpose. Twenty-four patients were examined for traumatic pathology of the cervical rachis. In 7 cases with clinically minor traumas, the negative outcome of the traditional traumas, the negative outcome of the traditional exam was considered reliable and sufficient for therapeutic purposes. The extant 17 patients were examined also by means of CT, either to better dermine the characteristics of skeletal lesions already ascertained with traditional techniques or to asses the presence of clinically-suspected osteo-articular lesions, even with negative conventional X-rays. For 9 of these patients orthopedic treatment was considered sufficient, whereas 8 patients underwent surgery and were subsequently ...

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Bone metastases of an Ewing's sarcoma were detected by magnetic resonance imaging (MRI), when bone scan, CT and plain films were still normal. This is due to the ability of MRI to detect intramedullary metastases before involvement of the cortex. (Auth.).

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Spinal Ewing's sarcomas are rare and cause problems in differential diagnosis. The radiologic, nuclear medicine and CT findings in two children with histologically proven Ewing's sarcoma are presented and problems in differential diagnosis discussed. Biopsy should be done early. (orig.).

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Forty-one cases of mediastinal tumor examined by computed tomography were reviewed. CT findings of the mediastinal malignancy were as follows: 1) inhomogeneous density on contrast CT, 2) equivocaton of fat plane surrounding the tumor, 3) irregular margin. Benign teratoma had smooth margin and included fat or calcification density. Mediastinal seminoma was observed as a lobulated mass with no calcification on CT. These findings were similar to the patterns of malignant thymoma or lymphoma. Consequently, it was very difficult to differentiate between malignant thymoma and malignant lymphoma by CT. According to our data, malignant thymoma tended to expand to only one side of the anterior mediastinum and to invade the anterior chest wall. On the other hand, malignant lymphoma of anterior medistinal type expanded into the trachea and the superior vena cava. In patients with sarcoidosis, the enlargement of ...

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Small bowel obstructions can be distinguished into more simple and closed loop obstructions. The latter is a more severe condition which is often complicated by strangulation with vascular impairment, edema and intramural and mesenteric hemorrhage. Consequent arterial insufficiency rapidly leads to ischemia, infarction and necrosis. The radiologist plays a role in the early recognition of the closed loop obstruction and of any sign of strangulation. The role of CT in the diagnosis and workup of patients with suspected intestinal occlusion has been analyzed in the literature with reported 63% sensitivity, 78% specificity and 66% accuracy. CT is also capable of revealing the causes of occlusion in 73-95% of cases. The above CT signs allow to identify closed loop obstruction and also small bowel strangulation, thus supplying a valuable contribution to diagnosis and accurate preoperative evaluation. The conclusion is that ...

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While there have been many experimental and calculational investigations on absorbed dose distribution in the patient resulting from conventional X-ray procedures, such data for computerized tomography (CT) are still sparse. As this diagnostic procedure has shown a rapid increase in application during recent years, we have determined absorbed dose to body organs in a human phantom resulting from CT examinations. The exposure model consists of the heterogeneous MIRD-5 phantom and a suitable Monte-Carlo method to calculate absorbed dose to organs of interest. The exposure conditions are specified according to the exposure specifications of a CT-scanner currently in use. The calculations cover the range of body tissues of interest in terms of organ absorbed doses as well as a risk weighted absorbed dose. A detailed example showing the calculation of red bone marrow dose is given and a somatic effective dose equivalent Hsub(ES) ...

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Commercially available CT devices reconstruct cross-sectional slices of the human body. A sequence of such abutting cross-sectional slices can be, and usually is, used to obtain information about the region of the head, which requires several slices to cover it. However, there are situations for which such asequence of displays is far from optimal - for example, when one would like to see the anatomic relationship between two features appearing in different slices or the shape of a particular region or tumor. The Computer Aided Three-Dimensional Reconstruction and Imaging System (CATRIS), developed at our university, can build up a three-dimensional image from a series of CT cross-sections and can display its stereoscopic image on a three-dimensional graphic display system, thus providing helpful information for clinical use in recognizing the anatomic relationship between two features appearing in different slices or the shape of particular ...

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The objective of this study was to develop a method for 3D subtraction CT angiography and to optimize the visualization after semiautomatic segmentation. Ten patients with aneurysms of the abdominal aorta were examined using spiral CT. To reconstruct the vessels, as well as adjacent organs such as the liver and kidneys, one image data volume was acquired before and after injection of the contrast agent. The CT scans were obtained with a Siemens Somatom Plus 4. To improve the results of automatic segmentation, as well as visualization by maximum intensity projection (i.e. removal of bony structures), subtraction of both image volumes is necessary. However, small translation shifts disturb the subtraction process and produce artificial contours. To calculate the disparities along the three coordinate axes of two corresponding image volumes, a cepstrum filter is applied to a pair of image volumes. After detection of the ...

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As a consequence of the expanded use of long term hemodialysis and continuous ambulatory peritoneal dialysis (CAPD) treatments and extended life spans, complications of end-stage renal disease and dialysis treatments are being encountered with increasing frequency in these patients. Computed tomography can accurately depict many of the potential complications of end-stage renal disease on dialysis. This article presents the abdominal CT findings of 429 end-stage renal disease patients who are on either hemodialysis or continuous ambulatory peritoneal dialysis treatment.

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Purpose: To assess the role of CT in the evaluation of traumatic and spontaneous oesophageal perforation. Materials and methods: From March 2001 to May 2003, we studied 12 patients (7 males and 5 females; age range: 25-66 years, mean age: 43.5 years) with suspected oesophageal perforation due to motor-vehicle accidents (4 cases), stab wound (one case), post-intubation (2 cases), foreign body ingestion (2 cases) and spontaneous (3 cases). Five patients underwent standard chest and cervical radiography; two patients with suspected foreign body ingestion also underwent a gastrografin swallow study; all of the 12 patients underwent CT of the neck, chest and abdomen before and after intravenous, and in four cases oral, administration of contrast material. Results: In 5 patients with cervical, thoracic and abdominal trauma, the CT examination showed the presence of pleuroparenchymal injury (pneumothorax, pleural effusion and ...

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CT is the most accurate method to detect pulmonary emphysema in vivo. They compared prospectively two different methods for emphysema quantitation in 5 normal volunteers and 20 consecutive patients with chronic obstructive pulmonary disease (COPD). All subjects were submitted to function tests and HRCT; three scans were acquired at preselected levels during inspiration. The type and extent of pulmonary emphysema were defined by two independent observers under blind conditions. Disagreements were subsequently settled by consent. All subjects were also examined with expiratory spiral CT using a density mask program, at two different cut-off levels (-850,-900 HU). Visual score and expiratory spiral density mask values (-850 HU) were significantly correlated (r = 0.86), but the visual extent of emphysema was always higher than shown by expiratory spiral CT. The emphysema extent assessed with both CT methods ...

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Thirty-seven patients with histologic proof of cholangiocarcinoma at the confluence were examined by computed tomography (CT) to determine whether this examination is of value in the assessment of these patients for surgery and whether there are any features specific to this type of tumor. Thirty-two patients showed intrahepatic duct dilatation; six of these showed dilatation of ducts in one lobe only. Eighteen patients had intrahepatic low-attenuation areas, while eight had a mass lesion in the porta hepatis. The results of this study show that CT provides useful anatomic information preoperatively but that the appearances are nonspecific. Lobar atrophy is highly suggestive of hilar cholangiocarcinoma, either of long-standing or with unilateral portal venous involvement.

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We report the cranial CT and MRI findings in three children with Lyme disease (neuroborreliosis). The neuroimaging findings in children have been rarely reported. We found cranial MRI far superior to cranial CT. Ring-enhancing lesions have been described in acute disseminating encephalomyelitis and multiple sclerosis but not in neuroborreliosis. Although other infectious and inflammatory diseases cannot be excluded, Lyme disease should be included in the differential diagnosis and put forward as being the most likely diagnosis in the appropriate clinical setting. Gadopentetate dimeglumine is helpful in assessing the response to antibiotic treatment. (orig.)

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The usefulness of helical CT early phase images optimized by the SmartPrep method for evaluation of wall invasion by colorectal cancer was investigated. Between August 1997 and September 1998, CT was performed to evaluate the primary tumor and local extension in 10 consecutive patients with colorectal cancer confirmed by barium enema- and/or colonoscopy. Early-phase images were acquired by using SmartPrep application software. This method allows the optimal scan delay time to be obtained by continuous monitoring of increases in CT values after injection of contrast medium. Sections of the surgical specimens, close to the same plane as the CT images, and of the same slice thickness, were analyzed histopathologically. All 10 cancers, regardless of size, showed strong enhancement on the early-phase images (81.4-112 HU, mean: 95.1 HU). The strongly enhanced image areas on CT ...

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Purpose: Evaluation of the diagnostic efficacy and cost-benefit of contrast enhanced CT (CT) and MRI pre- and post-SPIO-particles in focal hepatic disease with consideration of therapeutic outcome. Results: In 34/52 (65.4%) of the cases the correct diagnosis was primarily stated by CT (sensitivity [se.] 85.2%, specificity [sp.] 44.0%). In additional 10/52 of the cases unenhanced MRI (se. 91.4%, sp. 75.0%) enabled correct diagnoses, and in another 6 cases the diagnosis was established only by SPIO-MRI (se. 100%, sp. 86.7%). Considering the possible therapeutic recommendation arising from each modality, CT would have induced needless therapy costs of 191,042 DM, unenhanced MRI of 171,035 DM, and SPIO-MRI of 7,311 DM. In comparison to the real therapy costs of 221,873 DM, this would have corresponded to an unnecessary increase of therapy costs of 86.1%, 77.1%, and 3.3%, respectively. In two cases (91 ...

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Fracture toughness data of pre-cracked Charpy single-edge bend, SE(B), specimens are compared with those of standard compact, C(T), specimens in the upper shelf and ductile-to-brittle transition regimes. Charpy sized SE(B) specimens provide ductile fracture toughness data, which are compatible with those of standard C(T) specimens. Statistical methods such as the exponential curve fitting method (ECF), the engineering lower bound toughness method (ELB), and the Master Curve method (MC) are used to provide meaningful lower bound cleavage fracture toughness estimates from the toughness scatter of the Charpy sized SE(B) specimens in the ductile-to-brittle transition regime. In this regime, according to the ELB and MC methods, SE(B) specimens provide cleavage toughness data, which tend to be non-conservative compared to those of standard C(T) specimens. However, analyses based on the exponential curve fitting method show good ...

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This paper presented a technique to compensate for distorted secondary currents. Since current distortion can cause operating time delays in protective relays, attempts are made to minimize current transformer (CT) saturation by choosing a CT with a voltage rating that is at least twice that required for the maximum steady-state symmetrical fault current. However, the possibility of saturation still exists because of the DC component of an asymmetrical fault current and the remanent flux in a CT core. An advanced algorithm for the compensation of the distorted signal due to CT saturation was proposed. The secondary current can be expressed as the linear combination of sinusoidal and exponential signals, if no saturation occurs. In this study, the algorithm first utilized the third difference function for detecting the start and end of saturation in real-time. The AR model-based FIR filter and the least ...

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January, 1992, to October, 1995, sixty-four patients with advanced head and neck cancer underwent head and neck reconstructive surgery using myocutaneous or revascularized flaps; in the same period, all patients were consecutively examined with CT and MRI. Myocutaneous flaps were used in 26 patients: 12 flaps were tubular and 14 linear. Revascularized flaps were used in 38 patients: to repair a large defect in 26 patients (14 latissimus dorsi flaps and 12 temporal muscle flaps) and to repair an oral damage in 12 patients (5 revascularized radial and 7 jejunal flaps). CT and MR images of myocutaneous flaps showed the flaps as fatty areas, repairing large surgical defects, hypodense at CT and hyperintense at MRI, with no post-contrast enhancement. The appearance of revascularized flaps at CT and MRI depends on the characteristics of the structure used to repair the surgical defect: jejunal and radial ...

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Purpose of this work is to investigate the role of Helical CT and the usefulness of three-dimensional (3D) imaging for pre-operative planning and follow-up of reconstructive maxillofacial surgery with alloplastic material in neoplastic disease involving this region. From 1996 to 1999 eleven patients were examined with Helical CT and 3D images for planning of maxillofacial plastic and reconstructive surgery for advanced cancer of this anatomically complex region. A 3D-modulated titanium mesh (100%) or micro nets was used to rebuild the anterior surface of maxillary bone and the orbital floor. The mesh was cut to the appropriate size and shape and curved where necessary. Within the residual sinusal cavity a siliconed filling was used surmounting an acrylic prosthesis with dental arch to rebuild the palate. A rehydrated bovine pericardium was affixed and moduled on the borders in two cases only. Three-dimensionally reconstructed ...

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Aim: To evaluate the role of computed tomography (CT) in needle placement for ganglion impar blocks, and to determine the efficacy of CT-guided ganglion impar blocks in the management of coccydynia. Materials and methods: The results of ganglion impar blockade in eight patients with coccydynia secondary to trauma or unknown cause were reviewed. The diagnosis of coccydynia was based on clinical history, location of pain, and response to previous diagnostic and therapeutic procedures. The eight patients were treated with CT-guided ganglion impar blocks to manage their coccyx pain after conservative procedures, including oral medication and cushions, failed to provide relief. All patients were subjected to ganglion impar blocks under a thin-section CT-guided technique for needle placement, using a mixture of bupivacaine and triamcinolone. The patients were followed-up for a period of 6-months. Results: ...

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The accurate staging of rectal carcinoma is very important for treatment planning. The histological data obtained from surgical specimens of 22 patients with rectal carcinoma were compared with pre-and postoperative endorectal US findings and with preoperative CT results. According to an adapted version of Astler and Coller classification, the different degrees of tumor spread into the rectal wall were represented as follows: stage A: 1 patient; stage B1: 5 patients; stage B2: 6 patients; stage C1: 1 patient; stage C2: 8 patients and stage D: 1 patient. Preoperative staging, based on the overall results of CT and US, was in agreement with histology in 19 of 22 cases. Individual analysis of US and CT results, in comparison with histological data, showed US staging accuracy to be 77.3% (17/22 patients). US accuracy in demonstrating tumor spread into the rectal wall (stages A, B1, C1) was 100% (7/7 patients); US was 70% ...

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To elucidate the dynamic features of CT scans in peripheral cholangiocarcinoma for the differentiation of this tumor from various primary hepatic neoplasms. Materials were 24 cases of pathologically confirmed peripheral cholangiocarcinoma. Contrast enhancement patterns of central and peripheral portion of the masses were analyzed at three phases including arterial dominant(22), tissue equilibria(24), and postequilibria(9). Other associated CT findings and laboratory data were analyzed. Serum total bilirubin was mostly below 2 mg/dl(22/24), hepatitis B surface antigen was positive in only 9%, serum alphafetoprotein was elevated in 18%, carcinoembryonic antigen in 47%, cancer antigen 19-9 in 60%. In the arterial dominant image(22), 50% of the cases showed peripheral hyperdensity and 50% total hypodensity. In the tissue equilibrial images(24), 63% showed total hypodensity, 25% peripheral hyperdensity, and 13% total isodensity. In the ...

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Non-destructive Evaluation (NDE) plays a major role in ensuring the safe and reliable operation of PHWRs which are the mainstay of India's nuclear power programme. An important in-service inspection (ISI) requirement in these reactors is carried out through Eddy Current Testing (ECT) of the pressure tube (PT)/calandria tube (CT) assemblies. The material of construction of these assemblies is zircaloy-2. The two main objectives of this ISI are the detection of garter spring between CT and PT and the profiling of gap between CT and PT. The paper discusses the work carried out at the authors' laboratory on the development of ECT probes for ISI of PT/CT assemblies. Emphasis has been given on the work done on the design and optimisation of the probes using computer modeling. A 2-D finite element code has been developed for this purpose. The code is developed around a diffusion equation which can be derived ...

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The authors carried out a retrospective study on 4 years' work on a series of patients with proved active tuberculosis examined in the Departments of Bronchopneumology and Infectious Disease of the Arezzo Civil Hospital. The population was heterogenerous from the immunologic viewpoint. This paper compared the effectiveness of Computed Tomography (CT) with that of conventional chest radiography (CR) in the diagnosis and prognosis of tuberculosis. All patients underwent chest CR in double projection and conventional CT studies of the chest; 16 patients were also submitted to high resolution CT (HRCT). Consolidation was the most frequent parenchymal lesion in immunocompetent patients; it was often associated with cavitation, with no clear topographic prevalence in the upper lobes. Pleural effusion, as the only sign of disease and with empyema features, was found in 10 immunocompetent patients. No predominant pattern was found ...

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A noninvasive, simplified method using inhalation of stable xenon (Xe"s) and computed tomographic (CT) scanning to estimate regional cerebral blood flow (rCBF) and regional partition coefficient (r#lambda#) is described. Twenty-four patients with cerebrovascular occlusive disease and six volunteer controls inhaled 30% Xe"s and 70% oxygen for 180 seconds and exhaled for 144 seconds during serial CT scanning without denitrogenation. The end-tidal Xe"s concentration was continuously monitored with a thermoconductivity analyzer to determine the build-up range (A value) and build-up rate constant (K value) for arteries with the curve fitting method. The time-CT number (Hounsfield unit) curve for cerebral tissue during the Xe"s washin and washout phases was used to calculate r#lambda# and rCBF using least squares curve fitting analysis. The resultant r#lambda# and rCBF map demonstrated a reliable distribution between the gray and ...

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To assess the CT findings of intrahepatic cholangiocarcinoma associated with hepatolithiasis. The CT features of 26 patients with cholangiocarcinoma and hepatolithiasis were reviewed and compared with those of 23 patients with intrahepatic stones alone, acting as control subjects. CT findings were analyzed for tumor appearance and adjacency to hepatolithiasis. We studied clinical findings, noting the presence or absence of wall thickening or soft tissue attenuation within the bile duct, the luminal diameter of dilated bile duct, and the presence of periductal enhancement, and compared these with the findings for control groups. CT images of the tumor revealed a hepatic low-attenuating mass with peripheral rim enhancement(n = 14,54 %), or periductal thickening, or low-attenuating lesions in segmental dilatation of intrahepataic bile ducts(n = 12, 46 %). Most hepatic tumors were seen in areas adjacent to ...

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To illustrate frequently encountered anatomic variations on PNS computed tomography(CT) and to assess their clinical significance. CT findings of 1523 patients, who underwent PNS CT with no history of sinus surgery, were reviewed, and prevalence of each anatomic variation and its relationship with mucociliary clearance pathway was evaluated. Two categories of anatomic variations were encountered. The first group included variations of the turbinates, such as concha bullosa(28.6%), paradoxical middle turbinate(31.5%), of the uncinate process, such as medially bent or folded(36.3%), laterally bent(3.7%) or uncinate bulla(0.5%), of the ethmoidal sinus, such as Haller's cell(28.2%), large agger nasi cell(9.6%) or large ethmoidal bulla(23.5%) and nasal septal deviation(24.1%), which might cause obstruction of mucociliary clearance pathway and thus give rise to secondary obstructive sinusitis. The second group included ...

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Mycobacterium xenopi is one of the most common agents responsible for nontubercolar mycobacterial pulmonary disease on AIDS patients. These lesions have been studied with conventional radiography while CT has been used in patients with a specific mycobacterioses or non-AIDS pulmonary conditions from Mycobacterium xenopi. 12 AIDS patients were examined. They had pulmonary lesions from Mycobacterium xenopi, patients age ranged 30 to 46 years. All patients had CD4 blood levels lower than 250 cells/mL and Mycobacterium xenopi in the sputum. All patients underwent a standard chest radiograph and a CT examination. CT images were evaluated by three radiologists independently and the definitive diagnosis was made in the presence of a fourth radiologist. Chest CT showed parenchymal consolidation in 66% of cases, associated with bilateral basal bands in 16% of cases. Consolidation was unilateral in 41% of cases ...

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Aim of this study was to evaluate the sensitivity of virtual colonoscopy (CT colonography) in the identification of colorectal cancer and to define the limitations and the advantages of this imaging modality, as well as indications to the examination. It was examined prospectively 62 symptomatic patients aged 36 to 82 years (28 women and 34 men). All patients underwent both conventional and virtual colonoscopy on the same day; the conventional examination allowed exploration of the entire colon. Conventional colonoscopy identified 89 lesions 3-50 mm in diameter, namely 84 benign and 5 malignant lesions. No lesions were identified in 12 patients. CT colonography identified 52 of the 89 lesions, with 57.1% diagnostic accuracy. They were 11 false positives (82.5% positive predictive value and 52.2% specificity) and 37 false negatives (24.5% negative predictive value and 58.4% sensitivity). Sensitivity was significantly higher (85.7%) for polyps ...

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Both x-ray and optical cone-beam CT (CBCT) scanners are limited by scattered photons that contaminate the primary images. Transparent radiochromic gels and plastics are anticipated to produce less scattering than polymerization gels and hence result in reconstructed dose distributions with greater contrast and dynamic range. Four methods of scatter measurement were investigated to quantify scatter fractions using an in-house optical CBCT scanner. The methods consisted of generating either 'coin' shadows or primary beamlets in transmission images. The four methods generated similar results of 10% scatter fractions in gel transmission images for this particular scanner configuration with both leuco crystal violet and carbon black micelle gels. The scatter contributions were distributed as 5% from micelle gel, 2% from Teflon wall, 2% from refractive index matching liquid and 1% other sources. Applying a uniform background subtraction of 2% of open ...

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Open pit oil sands mining involves the disturbance of thin overburden covers of Boreal forest lands that must be returned to equivalent land capability after mining activities have ceased. Before mining starts, any wetlands are drained, timber is harvested, and peat, topsoils and subsoils are stockpiled for later use. This article discussed wetland reclamation activities conducted by Suncor Energy at its open pit mining operations. Research facilities were constructed in order to determine if wetlands constructed with consolidated tailings (CT) and pond effluent water (PEW) were able to support a sustainable vegetation community. Thirty-three cat-tail plots were established at the facility as well as unplanted plots in order to determine how quickly natural establishment occurred. Shoreline plug transplants and transplants from a natural saline lake were also introduced. Within 5 years, over 23 plant species had naturally colonized the CT ...

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A Real-Time Neutron Radiography (RTNR) system and a high speed X-ray Computed Tomography (X-CT) system are used to determine the flow regime, the instantaneous cross-sectional averaged void fraction, and the time averaged void fraction in a vertical annulus flow channel. A standard optical video system is also used to observe the flow regime. The annulus flow channel is operated as a bubble column and measurements are obtained for gas flow rates form 0.0 to 30.0 l/min. The flow regimes observed by all three measurement systems via image analysis shows that the results agree well with each other. Both the RTNR and the X-CT systems show that the time averaged and cross-sectional averaged void fraction increases with increasing superficial gas velocity. Time and cross-sectional averaged void fractions determined by the RTNR system agree within 4% with those determined by the high speed X-ray CT technique. (orig.).

International Nuclear Information System (INIS)

The combination of functional and morphological imaging technologies such as positron emission tomography (PET) and X-ray computed tomography (CT) has shown its value in the clinical and preclinical field. However, CT provides only very limited soft-tissue contrast and exposes the examined patient or laboratory animal to a high X-ray radiation dose. In comparison to CT, magnetic resonance tomography (MRI) provides excellent soft-tissue contrast and allows for nuclear magnetic resonance spectroscopy (NMRS) or functional MRI (fMRI). Thus, the combination of PET and MRI has been pursued for several years. First approaches have succeeded using conventional photo multiplier tube (PMT) technology together with light fibers to transfer scintillation light away from the high magnetic field. Latest PET/MRI developments use solid-state light detectors that can be operated even at high magnetic fields. Initial pilot studies with ...

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We investigated a method of analyzing the hemodynamics of the lung mass by contrast enhanced dynamic computed tomography (dynamic CT) to determine the difference in vascular supply between the pulmonary artery and bronchial artery using an experimental model. Our experimental model consisted of two injectors connected to two tubes, representing the pulmonary artery and bronchial artery, which were further connected to a chamber representing the lung mass. Following infusion of contrast medium into each tube with some delay time, dynamic CT scans were performed to obtain time density curves of the two tubes and the chamber. Using the time-density curve of contrast passage, flow rates from the two tubes into the chamber were calculated by the curve fitting method. Calculated values correlated well with the adopted flow rates of fluid from the injectors (r=0.893) in the experiment. The results indicate our method of individually measuring flow ...

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We reported three cases of acute intracranial tuberculosis including miliary tuberculosis, basal meningitis, tuberculomas and neuritis of cranial nerves. All patients had native and contrast enhanced CT and MRI scans. MRI revealed more granulomas and a better imaging contrast in the detection of basal meningitis. Neuritis was diagnosed only with the MRI. MRI scans should be prefered as the imaging procedure in clinically presumed intracranial tuberculosis. (orig.) [Deutsch] Die Befunde von drei Patienten mit intrakranieller Tuberkulose (intrakranielle Miliartuberkulose, Meningitis tuberculosa, Neuritis und Tuberkulome) in der Magnetresonanztomographie (MRT) wurden mit der Computertomographie (CT) verglichen. Sowohl die MRT als auch die CT wurden nativ und nach Kontrastmittelgabe durchgefuehrt. Die MRT zeigte sich im Nachweis von Granulomen insbesondere im Bereich des Hirnstamms ueberlegen. Ebenso wurde ein hoeherer ...

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Iodixanol is a new nonionic dimer, isotonic with blood at all clinically relevant concentrations. Iodixanol (270 mg I/ml) was compared in a double-blind, randomized, parallel-group, phase-III study to the monomeric nonionic iohexol (300 mg I/ml) for evaluation of safety, tolerability and radiographic efficacy during cerebral CT. One hundred adult patients scheduled to undergo contrast-enhanced cerebral CT were randomly allocated to receive either iodixanol or iohexol. All completed the trial. Safety was evaluated by recording discomfort and other adverse events, tolerance by assessing intensity and incidence of discomfort. Radiographic efficacy was assessed from the diagnostic information and the radiographic density. No serious adverse events occurred. One patient (2 %) in the iodixanol group and one patient (2 %) in the iohexol group experienced a transient reddening at the neck and lower neck-line, respectively. Both contrast agents were ...

International Nuclear Information System (INIS)

The effect of fetal distress on the neonatal brain was investigated by neonatal CT brain scan, FHR monitoring and mode of delivery. This study involved 11 cases of full term vertex delivery in which FHR was recorded by fetal direct ECG during the second stage labor. All infants weighed 2,500 g or more. FHR monitoring was evaluated by Hon's classification. Neonatal brain edema was evaluated by cranial CT histgraphic analysis (Nakada's method). 1) Subdural hemorrhage was noted in 6 of 7 infants delivered by vacuum extraction or fundal pressure (Kristeller's method). 2) Intracranial hemorrhage was demonstrated in all of 3 infants with 5-min. Apgar score 7 or less. 3) Two cases with prolonged bradycardia and no variability had intraventricular or intracerebral hemorrhage which resulted in severe central nervous system damage. 4) The degree of neonatal brain edema correlated with 5-min. Apgar score. 5) One case with prolonged bradycardia and no ...

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Selective alveolo-bronchography (SAB) has been routinely used to evaluate anatomical changes in the bronchiole and its distal air spaces. A narrowing of the bronchiole and abnormal pooling of contrast medium in the destroyed air space are the prime findings. Since the object of radiography is extremely thin, direct magnification radiography is mandatory to obtain radiologic details. However, the problem with this technique is that radiographic quality varies depending upon the size of the patient and the concentration of contrast medium to be introduced in the lung. This study had two goals. One was to improve the image quality of SAB by Fuji Computed Radiography (FCR). FCR provides radiographs with a good contrast and stable density throughout a wide range of exposure factors which occur in the use of SAB. The other goal was to separately evaluate morphological abnormalities in the outer and inner zones of the lung using X-ray CT. This idea was derived from our ...

International Nuclear Information System (INIS)

Forty resected cases of intrahepatic cholangiocarcinoma were classified into four types according to the gross appearance; type I: mass forming type (n=8), type II: mass forming with periductal infiltrating type (n=20), type III: periductal infiltrating type (n=9) and type IV: intraductal growth type (n=3). Diagnostic features of these four types were studied. Peripheral enhancement was a common angiographic feature and tumor stains were recognized in 88%, 20%, 0%, 33%, respectively. Angiography and dynamic computed tomography (D-CT) were useful in differential diagnosis with hepatocellular carcinoma. Accuracy rate in diagnosis of portal vein involvement by angiography and D-CT was 82% and 91%, respectively. MRI was more useful in tumor detection than D-CT in cases with attenuation difference, in 55% of type II and in 75% of type III. Increase of arterial involvement, biliary tract involvement and portal vein involvement, ...

International Nuclear Information System (INIS)

Computed tomography (CT) of the thorax shows early promise of important diagnostic advances. We believe that CT often provides information superior to that provided by standard roentgenographic techniques, is capable of significantly influencing patient management, and in selected instances, offers unique information not available by other methods. Computed tomography permits the imaging of mediastinal structures not possible with conventional roentgenographic methods and can diagnose with certainty benign mediastinal conditions such as pericardial cysts and focal or diffuse accumulations of fat. It is ideal for detecting pleural abnormalities and for displaying underlying parenchymal disease in patients with complex pleuroparenchymal shadows on conventional films. Pulmonary metastases unseen on the plain chest film can be detected with greater sensitivity than by any other method. Future applications of CT include the ...

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Cholangiocarcinoma may be associated with recurrent pyogenic cholangitis as a complication of longstanding proliferative cholangitis in the presence of intrahepatic stones. Sonographic and CT findings of six patients with cholangiocarcinoma of the liver associated with recurrent pyogenic cholangitis are presented. The cases were among 128 patients who underwent partial resection of the liver because of recurrent pyogenic cholangitis and its complication. On sonogram the mass was depicted in four patients as an ill-defined heterogenously echogenic mass and in one patient as a bulging contour; in the remaining one case the mass was not detected. There were small or large, shadowing or non shadowing stones within the tumor in five cases. In one case, the stone was in the duct proximal to the tumor. On CT scans of four patients, the tumors were depicted as an ill-defined, irregular low attenuation masses with variable contrast enhancement, the ...

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The paper studies subphrenic inflammatory abscesses and splenic fluid collections after splenectomy for trauma. These complications may appear early or late postoperatively; they are easily demonstrated with computerized tomography, which permits accurate spatial assessment of the lesions and appropriate treatment with percutaneous drainage. It has been also investigates the diagnostic accuracy of the CT in subphrenic inflammatory conditions after emergency splenectomy for traumatic spleen rupture and found that CT is a precious tool for rapid and easy diagnosis and follow-up of subphrenic abscesses treated with percutaneous drainage. [Italian] Scopo del lavoro e' di valutare il ruolo della tomografia computerizzata nelle flogrosi subfreniche secondarie a splenectomia d'urgenza per rottura traumatica della milza, documentando come tale metodica risulti accurata nel diagnosticare e monitorare in modo semplice e rapido ...

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T_2 weighted ultra-short turbo spin echo sequences were used in five individuals with variations in echo times, delayed triggering and echo intervals. To reduce movement artifacts all examinations were carried out with ECG and respiratory triggering. The sequences giving optimal image quality were then employed in 19 patients having various pulmonary abnormalities. Image resolutions, artifacts, image contrasts and diagnostic value were then judged by two observers and compared with CT. In the first study, a diastole-triggered UTSE sequence with the shortest echo proved optimal (T_E=90 ms, T_R=2-4 s, echo=9 ms, turbo factor=19). In the patient series studied, MRT was inferior to CT with regard to resolution and number of artifacts, but better in respect of contrast and diagnostic value. Using UTSE of the lung, MRT can produce images of good quality. Compared with CT, contrast is better with MRT, offering diagnostic ...

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During their life, intervertebral discs undergo degenerative changes which need not necessarily become lesions. Conventional X-rays do not provide information on the condition of the intervertebral discs, so MRT or CT are recommended as primary techniques as they are non-invasive. Invasive methods like myelography and especially discography should not be used unless a case is highly problematic. In infants with pains in the back, MRT should be carried out as early as possible as there is nearly always an organic cause. (orig.) [German] Die Bandscheibe ist im Laufe des Lebens degenerativen Veraenderungen unterworfen, die klinisch zu Beschwerden fuehren koennen, aber nicht fuehren muessen. Konventionlle Roentgenaufnahmen lassen zwar die Hoehenminderung des Bandscheibenfachs und begleitende knoecherne Veraenderungen erkennen, nicht aber den Zustand der Bandscheibe selbst. Die Beurteilung der Bandscheibe und des Knochens gelingt mit der CT, die ...

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Patients with heterotaxy syndrome often have complex cardiac and extracardiac anomalies requiring further detailed diagnostic evaluation. They often present severe cardiac failure early in life. Newer radiological modalities in the form of spiral computed tomography (CT) and three-dimensional reconstruction of spiral CT allow clear definition of the anatomy of these anomalies. A 59-year-old woman was diagnosed with polysplenia and multiple anomalies in an abdominal ultrasonography (US) during a control medical examination due to a trivial dietary mistake. She was then referred to our institution for further examination of these anomalies and an additional thoraco-abdominal computed tomography (CT) examination. The patient was totally asymptomatic at the time of admission. There was no significant past history and no abnormal laboratory data. We performed abdominal, pelvic and thoracic CT examinations ...

International Nuclear Information System (INIS)

In spite of the improved imaging techniques currently available, mortality for pancreatic cancer is still high, and pancreatics is often diagnosed only in its advanced stages. The authors investigated the value of different imaging techniques - i.e., US, CT, and ERCP - for an early diagnosis, when a more effective (curative?) treatment can be suggested. Fifty-six cases of pancreatic cancer and 36 cases of chronic pancreatitis were evaluated. The results indicate that ERCP, with the help of statistical methods, is superior to US and CT not only in evaluating early neoplastic or inflammatory lesions, but also for their differential diagnosis. In the letter case, ERCP can sometimes be used as a valid alternative to fine-needle aspiration biopsy.

British Library Electronic Table of Contents (United Kingdom)

Study Type - Therapy (case series)Level of Evidence 4 OBJECTIVE To present our experience of retroperitoneoscopic partial adrenalectomy (RPA) for small adrenal tumours, as with modern imaging methods small adrenal lesions are being diagnosed more commonly, and retroperitoneoscopic adrenal surgery for small adrenal tumours (PATIENTS AND METHODS We retrospectively reviewed the records of 389 consecutive retroperitoneoscopic adrenalectomies from September 2005 to December 2008, 88 of which were small adrenal tumours and treated by RPA. Ultrasonography and computed tomography (CT) were used in all patients before RPA, and magnetic resonance imaging or positron emission tomography/CT in some patients. We used RPA for adrenal tumours and total adrenalectomy for adrenal cancer. During the surgery...

International Nuclear Information System (INIS)

Computed tomography (CT) of the neck and mediastinum was performed in 16 patients with renal osteodystrophy. Thirty out of 34 excised parathyroid glands weighing more than 500mg were diagnosed preoperatively (88.2%). Scintigraphy of the neck with _2_0_1TlCl and sup(99m)TcOsub(4-) was also performed in 15 patients. The introduction of subtraction method with a mini-computor in the scintigraphy has remarkably improved the visualization rate of parathyroid glands. Ultrasonic echography (US) of the neck which is able to obtain not only transverse butalso longitudinal imaging was done in 7 patients. It has about same detection rate of the glands with CT. The visualization of enlarged parathyroid glands is valuable not only for localization but also for undeniable evidence of hyperparathyroidism. Also, repeated follow-up examination can determine the effectiveness of conservative treatment. (author).

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Twenty-two out of 31 patients with chronic renal failure and secondary hyperparathyroidism who underwent parathyroidectomy before operation underwent non-invasive image diagnosis of parathyroid glands by computed tomography (CT), scintigraphy with /sup 201/TlCl and /sup 99m/TcO/sup 4 +/, and/or ultrasonography. CT visualized 39 of 45 parathyroid glands (86.7%), weighing more than 500 mg. Scintigraphy with a subtraction method using a computer performed the diagnosis in 19 of 27 glands (70.4%). Ultrasonography detected 21 of 27 glands (77.8%). Image diagnosis was also useful in the postoperative follow-up study. The non-invasive image diagnosis of parathyroid glands in patients with chronic renal failure is thus valuable for 1) definite diagnosis of secondary hyperparathyroidism, 2) localization, and 3) diagnosis for effectiveness of conservative treatment.

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Two cases of focal nodular hyperplasia (FNH), in which ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MR) studies detected an atypical hemorrhagic pattern associated with an intrahepatic arterio venous malformation (AVM) around the growths, are presented. In both cases, histology demonstrated a very early regenerative stage and necrotic-hemorrhagic areas within the lesions. In these cases, the analysis of radiological findings, surgical specimens and histology seemed to confirm the pathogenetic hypothesis suggested by Wanless: in normal liver parenchyma, a ``blood steal`` phenomenon due to congenital or acquired intrahepatic AVM could cause ischemic damage, appearing as a hemorrhagic necrotic area, the extent of which depends on the degree of residual portal supply. (orig.)

British Library Electronic Table of Contents (United Kingdom)

Abstract Crouzon syndrome is characterized by premature fusion of sutures and synchondroses. Recently, the first mouse model of the syndrome was generated, having the mutation Cys342Tyr in Fgfr2c, equivalent to the most common human Crouzon/Pfeiffer syndrome mutation. In this study, a set of micro-computed tomography (CT) scannings of the skulls of wild-type mice and Crouzon mice were analysed with respect to the dysmorphology caused by Crouzon syndrome. A computational craniofacial atlas was built automatically from the set of wild-type mouse micro-CT volumes using (1) affine and (2) non-rigid image registration. Subsequently, the atlas was deformed to match each subject from the two groups of mice. The accuracy of these registrations was measured by a comparison of manually placed landma...

International Nuclear Information System (INIS)

Surgical resection is the only curative treatment strategy for intrahepatic cholangiocarcinoma (CC). Therefore, accurate staging is essential for appropriate management of patients with CC. We assessed the usefulness of 2-["1"8F]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) in the staging of CC. We undertook a retrospective review of FDG PET images in 21 patients (10 female, 11 male; mean age 57 years) diagnosed with CC. Ten patients had hilar CC and 11, peripheral CC. Patients underwent abdominal magnetic resonance imaging (MRI) (n=20) and computed tomography (CT) (n=12) for the evaluation of primary tumours, and chest radiography and whole-body bone scintigraphy for work-up of distant metastases. For semi-quantitative analysis, the maximum voxel standardised uptake value (SUV_m_a_x) was obtained from the primary tumour. All peripheral CCs showed intensely increased FDG uptake, and some demonstrated ring-shaped uptake corresponding to ...

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A solid pseudopapillary tumor is an uncommon tumor of the pancreas that rarely metastasizes to other organs and usually shows good prognosis. An extrapancreatic tumor arising from a solid pseudopapillary tumor is very rare. We report a case of an atypical extrapancreatic solid pseudopapillary tumor that arose from the great omentum and disseminated to the peritoneum, and discuss the radiologic findings, including the CT, US, and MRI.

UK PubMed Central (United Kingdom)

Eilatin-containing ruthenium complexes bind to a broad range of different nucleic acids including: calf thymus (CT) DNA, tRNA^Phe, polymeric RNAs and DNAs, and viral RNAs including the HIV-1...Full Text Available

International Nuclear Information System (INIS)

During their life, intervertebral discs undergo degenerative changes which need not necessarily become lesions. Conventional X-rays do not provide information on the condition of the intervertebral discs, so MRT or CT are recommended as primary techniques as they are non-invasive. Invasive methods like myelography and especially discography should not be used unless a case is highly problematic. In infants with pains in the back, MRT should be carried out as early as possible as there is nearly always an organic cause. (orig.)

International Nuclear Information System (INIS)

To analyze the enhancement patterns and morphology of peripheral cholangiocar-cinomas (CCs), as seen on three-phase helical CT. Three-phase helical CT scans of 25 cases of 24 patients with pathologically-proven CCs were retrospectively reviewed. After intravenous administration of contrast media, scans of the hepatic arterial phase (HAP) were obtained at 30 seconds, of the portal venous phase (PVP) at 70 seconds, and of the delayed phase (DP) at 3 minutes. Linear, dense, marginal enhancement was seen in 17 CCs (68%), mainly on HAP images (64%) while thick, band-like, peripheral enhancement was seen in 18 (72%), on either PVP (52%) or DP (44%). Internal enhancement was observed in 23 CCs (92%) on PVP (68%) and/or DP (88%), and 19 CCs (76%) among them showed incomplete enhancement of stippled and/or septated patterns. Most (76%) were seen throughout all three phases to be hypoattenuating, as compared to the surrounding parenchyma. On HAP, ...

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AIM: To compare the adequacy and acceptability of Picolax and Citramag bowel cleansing agents for CT colonography. MATERIALS AND METHODS: Multidetector row CT colonography was performed in 124 subjects; 43 had been prepared with Picolax and 81 with Citramag. Datasets were assessed for retained fluid and solid residue, and overall adequacy of segmental visualization. Preparation acceptability was also assessed. RESULTS: There was significantly less retained fluid with Picolax. The odds of being in the next higher category for retained fluid when using Picolax were 0.33 (CI: 0.22-0.50, p<0.0001) when compared with Citramag, for all segments combined. However there was significantly more retained solid residue with Picolax. The odds of being in the next higher category for retained residue when using Picolax were 2.44 (CI: 1.41-4.24, p=0.002) when compared with Citramag, for all segments combined. There was no significant difference with ...

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Objective: To investigate the value ofMSCT in observing the direct findings of hilar cholangiocarcinoma1Methods Multislice helical CT studies were performed on the upper abdomen in 19 consecutive patientswith painless jaundice1 Precontrast and dynamic contrast enhanced (25 s phase and 60 s phase) scanswere conducted, and 3D imageswere reconstructed using enhanced raw data in 15 cases1 The direct CT findings of hilar cholangiocarcinoma were studied by three radiologists respectively in a 32scale strategy1 The morphological features and extension of bile duct involvement by hilar cholangiocarcinoma were analyzed1 All the 19 caseswere pathologically p roved as hilar cholangiocarcinoma by surgery (15 cases) and ERCP ( 4 cases) 1 Results The direct findings and extension of hilar cholangiocarcinoma could be demonstrated in 14 out of 15 3D reconstruction images, 8 out of 19 in 25 s phase, and 7 out of 19 in 60 s phase of contrast enhancement scans, ...

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This study by CTES, L.C. meets two main objectives. First, evaluate the feasibility of using coiled tubing (CT) to drill 1.0 inches-2.5 inches diameter directional holes in hard rocks. Second, develop a conceptual design for a micro borehole drilling platform (MBDP) meeting specific size, weight, and performance requirements. The Statement of Work (SOW) in Appendix A contains detailed specifications for the feasibility study and conceptual design.

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Magnetic resonance imaging can be used in the trauma setting to detect fractures and associated soft tissue injuries of the musculoskeletal system. Magnetic resonance imaging complements plain radiography and CT for evaluating cancellous bone, cartilage and growth-plate injuries, and intra- and extraarticular supporting soft tissue structures. This review outlines typical applications and imaging consideration for injuries of the pelvis and lower extremity. (orig.) With 12 figs., 78 refs.

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The intrasphenoid form of basal cephalocele is uncommon. We describe the clinical, CT and MRI findings in two cases presenting in middle age with persistent cerebrospinal fluid rhinorrhoea. Emphasis is placed upon the imaging findings which aid in discrimination of intrasphenoidal cephalocele from more common causes of a sphenoid sinus mass. (orig.)

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The purpose of this study was to correlate MR imaging findings with pathology in experimental hyperoxia-induced acute lung injury, which has similar pathology to diffuse alveolar damage (DAD). Seventeen Yorkshire pigs were studied. These animals were exposed to more than 80% oxygen for 24, 48, 72, and 96 hours in a sealed cage. The lungs were removed and inflated with air infused through the trachea, and then examined by both MRI and high-resolution CT (HRCT). T1-weighted spin-echo (T1WSE), T2-weighted fast (T2WFSE), and half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequences were performed. Severity in MR findings and signal-to-noise ratios (SNR) on MR images were well correlated with pathological scores. CT values were also correlated well with pathologic scores. Abnormal SNR values were obtained from a pathological score of 5, whereas abnormal CT values were obtained from a pathological score of 15. ...

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To evaluate injury patterns of facet joints and associated soft tissue injuries in patients with acute traumatic cervical facet joint injuries. From among patients with cervical spine trauma, 27 with facet joint injuries, as seen on CT and MRI, were chosen for this study. CT scans were analyzed with regard to the location of facet joint injury, the presence or absence of facet dislocation or fracture, and other associated fractures. MR images were analyzed with regard to ligament injury, intervertebral disc injury, intervertebral disc herniation, and spinal cord injury. The most common location of facet joint injury was C6-7 level(n=10), followed by C5-6(n=8). Among these 27 patients with facet joint injuries, 12(44%) had bilateral injuries and 15(56%) unilateral injuries. Facet fractures were present in 17 cases(63%) and the fracture of inferior facet was more frequent than superior. Patterns of fracture were vertical, transverse, or ...

Science.gov (United States)

The objectives of this study were to evaluate the performance of the NucliSens easyMAG platform for nucleic acid extraction from different clinical specimens compared to NucliSens miniMAG platform and manual QIAGEN extraction. The NucliSens easyMAG and the NucliSens miniMAG showed equal performance on 215 throat swabs since real-time nucleic acid sequence-based amplification scored the same samples positive for Mycoplasma pneumoniae (n=9) and Chlamydia pneumoniae (n=5) RNAs, although internal control RNA was slightly better detected with the NucliSens easyMAG (99.3% versus 96.8%). NucliSens easyMAG extracted nucleic acids more efficiently (higher recovery and/or fewer inhibitors) compared to QIAGEN extraction by showing, on average, lower Ct values in real-time LightCycler PCR, although 4 individual specimen out of 45 were found positive only with QIAGEN. For nine M. pneumoniae-positive throat swabs, the mean difference in Ct values between ...

International Nuclear Information System (INIS)

The risks from radiation exposure during radiological diagnosis has usually been estimated in relation to genetic changes. Relevant information has been expressed as the genetically significant dose. In this paper we attempt to produce an analogous measure for evaluating the somatic risk in the form of a somatically significant dose index for radiological and CT examinations. It is shown that, for both types of examination, the two risk factors may be entirely different. (orig.).

UK PubMed Central (United Kingdom)

PurposeTo describe clinical data and to characterize mutations in the transforming growth factor beta-induced (TGFBI) gene in patients from three unrelated Chilean...Full Text Available

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Intrahepatic cholangiocarcinoma is an uncommon tumor as primary hepatic neoplasm. Five cases of cholangiocarcinoma, mass forming peripheral type, are reported about its CT findings. They were manifested as a poorly marginated low density mass with a irregular stellate area. In one case, a cut section of the gross specimen following surgery showed a central callagenous scar and vessels within the necrotic tumor. (author).

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Forty-four patients with small cell carcinoma of the bronchus underwent CT and MR studies of the brain to detect cerebral metastases. All patients were studied with contrast-enhanced CT scans, short (T1-weighted) and long (T2-weighted), spin-echo (SE) and FLASH 90 grades sequences were also obtained. A quantitative comparison of the results was carried out to assess the sensitivity of the different techniques in the detection of brain metastases according to lesion diameter. Metastases were identified in 19/44 patients (43%). All techniques detected the lesions >2 cm; of the metastases <2 cm, 63/124 (51%) were detected only by GdDTPA SE-T1 and FLASH sequences and 11 more (9%) only by Gd-DTPA SE-T1 scans. All the lesions identified oh enhanced CT scans or on T2-weighted images were easily detected by Gd-DTPA scans. CT sensitivity was higher than that of pre-contrast SE-T1 and FLASH studies and only ...

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Bowel infarction is a rare and typical condition of the elderly; despite improvements in diagnostic imaging and vascular surgery, bowel infarction remains a major cause of acute abdomen, with mortality rates ranging 70-80%. Diagnosis on often late because clinical signs, laboratory data and radiologic findings are a specific. The authors investigated radiographic and particular CT patterns of intestinal infraction in 56 patients submitted to surgery within 12 hours of admission. We also report the CT findings of 5 of these patients who had reversible mesenteric ischemia. CT is more sensitive than radiography and does not exhibit the limitations of angiography (i.e., invasiveness, radiation exposure and complex organization). Therefore CT can presently be considered the method of choice in patients with suspected bowel infarction. [Italian] L'infarto intestinale rappresenta una malattia rara e ...

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CT and MRI of acquired abnormalities of the inner ear and cerebello-pontine angle present themselves with very typical findings. The imaging should be adapted to the pathology looked for and either CT or MRI should be used alone or in combination.CT, especially high resolution CT (HRCT), provides an excellent bone contrast, while MRI has a much superior soft tissue contrast. Acute inflammatory changes of the inner ear are solely depicted by contrast-enhanced MRI. HRCT excellently depicts osseous changes of the inner ear and cerebellopontine angle such as chronic ossifying labyrinthitis occurring after acute labyrinthitis, otosclerotic or traumatic changes. Tumorous changes not yielding to bony changes are best delineated by MRI. Posttraumatic hemorrhage and chronic fibrotic changes within the labyrinth are depicted by MRI, only. In conclusion HRCT and MRI are excellent methods to delineate acquired ...

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Purpose of this work is to evaluate the effectiveness and role of CT in blunt diaphragmatic injuries by reviewing our 8-year experience. It is reviewed the preoperative CT findings of 35 patients with surgically confirmed diaphragmatic rupture. Surgical repair was performed in the acute setting (within 12 hours of trauma) in 22 cases, and late (8 months-5 years) in 13 cases. Twenty-eight patients (80%) were examined with conventional CT and 7 (20%) with Helical CT. Of the 13 patients examined long after trauma, the left hemi diaphragm was ruptured in 12 cases (with visceral herniation in 4), and the right hemi diaphragm in 1, with no herniation. The diaphragmatic rent was found in the dome (15 cases, 43%), muscolotendinous junction (11 cases, 31%), muscular portion (8 cases, 23%), and at the muscular attachments on the ribs (1 case, 3%). As for the site of diaphragmatic injury, CT ...

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The purpose of this paper is to report the personal experience with helical CT evaluation of hepatocellular carcinoma treated with various percutaneous interventional procedures. From December 1996 to September 1998 it were examined with helical CT 41 patients (73 nodules in all) with hepatocellular carcinoma treated with percutaneous ablation therapies: conventional ethanol injection in 18 subjects (31 nodules), one-shot ethanol injection 3 (8 nodules), radiofrequency thermal ablation in 16 (25 nodules), and combined chemo embolization and ethanol injection in 4 (9 nodules). CT performed was 4-27 days after the last session, acquiring biphasic volumetric images in 14 patients and triphasic volumetric images in 27. A second treatment with subsequent CT study was performed for 28 lesions; 15 underwent 3 serial studies and 6 underwent 4 studies. Compared with pretreatment findings, the diameter was ...

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The main purpose of this work is to report the personal experience with addition of contrast-enhanced multiphase helical CT to unenhanced CT (Lipiodol CT) in the evaluation of patients with hepatocellular carcinoma treated with chemoembolization and to analyze the present role of oily agent CT. It has been retrospectively reviewed the examinations of 42 consecutive patients submitted to global chemoembolization over a 2-year period. CT was performed 18-30 days after the treatment. The Lipiodol CT study was carried out with volume acquisitions. It has been considered as nodules all well-defined areas with dense oily agent uptake; uptake itself was classified as: 0=absent, I=lower than 10% of the tumor volume; II=lower than 50%, III=50%, IV=homogeneous. Contrast-enhanced helical CT was performed with the 2-phase technique in 28 patients and ...

Science.gov (United States)

The knowledge of wound ballistics and of wounding mechanisms is mandatory for the radiologist to interpret the CT findings of gunshot wounds. The severity of a bullet wound depends on the characteristics of the tissue it goes through, i.e., tissue elasticity, density, thickness of the wounded body part, the type of tissue, its specific gravity, internal cohesiveness and anatomical relationships, as well as on missile characteristics, i.e., mass, shape, fragmentation and deformation. Bullet velocity is certainly a major factor in wounding, but it is only one factor. Two major wounding mechanisms exist the crushing of the bullet-struck tissue (forming the permanent cavity) and radial stretching (forming a temporary cavity). Bullet "yaw" is defined as the angle between the long axis of the bullet and its flight path. The yaw is directly proportional to tissue crushing and stretching: the wider the yaw, the most severe tissue crushing and stretching and, therefore, the ...

International Nuclear Information System (INIS)

For the evaluation of diseases of salivary origin, ultrasound and/or sialography is recommended instead of MRI. In cases of salivary tumor, ultrasound may be helpful in delineating superficial tumors. For small tumors no further imaging is needed. When dealing with a large tumor or a tumor in the deep lobe of the parotid gland, MRI is the preferred imaging method. Not only does MRI provide a large variety of soft tissue signal differences, but also the multiplanar facilities are helpful in delineating the extent of the tumor, whether located in the submandibular, sublingual, or parotid gland. Skull base invasion is often well seen by MRI. Subtle changes may be missed and in those cases CT is recommended to exclude or prove destruction of the skull base. For the evaluation of patients presenting with a recurrent pleomorphic adenoma, MRI is recommended in all patients. MRI delineates the extent and number of recurrent tumors better than palpation in most cases. No ...

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Purpose: In an experimental study, the correlation between the trabecular bone density of the different regions of the proximal femur and the fracture load in the setting of femoral neck fractures was examined. Methods: The bone mineral density 41 random proximal human femora was estimated by single-energy quanitative CT (SE-QCT). The trabecular bone density was measured at the greatest possible extracortical volume at midcapital, midneck and intertrochanteric level and in the 1 cm"3 volumes of the centres of these regions in a standardised 10 mm thick slice in the middle of the femoral neck axis (in mg/ml Ca-hydroxyl apatite). The proximal femora were then isolated and mounted on a compression/bending device under two-legged stand conditions and loaded up to the point when a femoral neck fracture occurred. Results: Statistical analysis revealed a linear correlation between the trabecular bone density and the fracture load for the greater regions, with the highest ...

International Nuclear Information System (INIS)

Sonography, subtraction scintigraphy, computed tomography and MRI were compared in 100 patients who had surgery 105 times for hyperparathyroidism (HPT). Surgical and pathological data were available for all operations. A total of 105 MR, 77 CT, 84 sonograms and 70 subtraction scintigrams were performed. The ability of the imaging modalities, individually and in combination, to detect HPT, histology, size, concomitant thyroid disease and location of the diseased glands has been evaluated. For primary HPT, sensitivity ranged from 68% for MRI to 40% for scintigraphy but was much lower for tertiary HPT with all modalities. The ability to identify diseased glands was strongly size dependent for all methods. If patients had had previous neck surgery, the most sensitive methods were MRI and scintigraphy and this also held true for patients with concomitant thyroid disease and ectopically located glands. The findings presented suggest that while sonography may be the only ...

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Experiments were conducted to confirm the isotropic spatial resolution of multislice CT with a 0.5 mm slice thickness. Isotropic spatial resolution means that the spatial resolution in the transaxial plane (X-Y plane) and that in the longitudinal direction (Z direction) are equivalent. To obtain point spread function (PSF) values in the X-Y-Z directions, three-dimensional voxel data were obtained by helical scanning of a bead phantom. The modulation transfer function (MTF) values were then obtained by three-dimensional Fourier transform of the PSF. Evaluation of the spatial resolution in the X-Y-Z directions by the MTF values showed that the spatial resolution in the Z direction does not depend on the reconstruction kernel used. It was also found that the spatial resolution in the Z direction, as compared with that in the X-Y plane, is superior with the standard kernel for the abdomen and is inferior with the high-definition kernel for the ears/bones. By performing ...

International Nuclear Information System (INIS)

In the case of injuries of the ankle joint, an imaging technique is expected to reveal the state of the bones, ligaments, and articular cartilage. Irrespective of novel imaging techniques, a plain radiography will be made in order to obtain a first picture of the injury. Examples are given, showing that further orientation along the Lauge-Hansen classification scheme of this type of injury helps to completely ascertain the damage to the Articulatio talocruralis. Further examinations applying specific methods such as arthrography will detect possible, isolated syndesmosis ruptures; lesions of the ligaments can also be directly detected by CT or MRT. The articular cartilage and its lesions can be visualized by a combination of CT and arthrography, but are better shown by the completely non-invasive MRT. This latter method also gives insight into pathological processes with the bone. It allows to detect necrotic bone regions and their ...

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Functional imaging of the pharynx used to be the domain of cineradiography, CT and ultrafast CT. The development of modern MRI techniques led to new access to functional disorders of the pharynx. The aim of this study was to implement a new MRI technique to examine oropharyngeal obstructive mechanisms in patients with obstructive sleep apnea (OSA). Sixteen patients suffering from OSA and 6 healthy volunteers were examined on a 1.5 T whole-body imager ('Vision', Siemens, Erlangen Medical Engineering, Germany) using a circular polarized head coil. Imaging was performed with 2D flash sequences in midsagittal and axial planes. Patients and volunteers were asked to breathe normally through the nose and to simulate snoring and the Mueller maneuver during magnetic resonance imaging (MRI). Prior to MRI, all patients underwent an ear, nose and throat (ENT) examination, functional fiberoptic nasopharyngoscopy and polysomnography. A temporal resolution of ...

International Nuclear Information System (INIS)

Tris(8-quinolinolato)aluminum(III) (Alq3) shows electronic absorption bands at 378, 360 (in a 1:1 mixed solvent of methanol and ethanol (ME) at 77 K), 334, 316, 300, 263, 255.8, and 233 nm in ethanol at room temperature. According to the polarized fluorescence excitation spectrum together with MO calculations, for instance, the 360 nm band is assigned to an LL CT transition (an intramolecular charge transfer transition between two ligands), and the 378 nm band to an LM/ML CT one (an intramolecular charge transfer transition between ligand and metal). Alq3 shows a broad fluorescence band peaking at around 478 nm in the ME matrix at 77 K. The emission spectrum measured with a phosphoroscope has two emission bands at 567 and 478 nm. The 567 nm band accompanies vibronic bands at 578 and 605 nm, being safely assigned to a phosphorescence of Alq3. The lifetimes of the 478 and 567 nm bands are both 5.4 ms. The lifetime of the 478 nm band together with ...

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Described is the diagnosis for the cancer extension of cholangiocarcinoma by various imaging techniques and processes to support the current surgical procedure based on preoperative biliary drainage. The cancer tends to locally extend horizontally and/or vertically and its diagnosis is important for surgical indication. For the indication, multi-detector raw CT (MDCT) and MR cholangio-pancreatography (MRCP) are useful and particularly, the former can give multi-phase (arterial, portal and delayed) images to reconstruct multiplanar (MPR) and CT angiographic 3D images, which have made the previous invasive examinations like angiography and percutaneous transportal contrasting unnecessary. MDCT and MRCP can almost complete the diagnosis of the extension. The operative procedure is decided dependently on the site of the lesion, and of which diagnosis, whether it is hepatic hilar/on upper bile duct or middle/lower ductal, is different. MDCT-MPR and ...

International Nuclear Information System (INIS)

A Real-Time Neutron Radiography (RTNR) system and a high speed X-ray Computed tomography (X-CT) system are compared for measurement of two-phase flow. Each system is used to determine the flow regime, and the void fraction distribution in a vertical annulus flow channel. A standard optical video system is also used to observe the flow regime. The annulus flow channel is operated as a bubble column and measurements obtained for gas flow rates from 0.0 to 30.01/min. The flow regimes observed by all three measurement systems through image analysis shows that the two-dimensional void fraction distribution can be obtained. The X-CT system is shown to have a superior temporal resolution capable of resolving the void fraction distribution in an (r,#theta#) plane in 33.0 ms. Void fraction distribution for bubbly flow and slug flow is determined.

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Image registrations that are based on similarity measures simply adjust the parameters of an appropriate spatial transformation model until the similarity measure reaches an optimum. The numerous similarity measures that have been proposed in the past are differently sensitive to imaging modality, image content and differences in the image content, selection of the floating and target image, partial image overlap, etc. In this paper, we evaluate and compare 12 similarity measures for the rigid registration. To study the impact of different imaging modalities on the behavior of similarity measures, we have used 16 CT/MR and 6 PET/MR image pairs with known 'gold standard' registrations. The results for the PET/MR registration and for the registration of CT to both rectified and unrectified MR images indicate that mutual information, normalized mutual information and the entropy correlation coefficient are the most accurate ...

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In our evaluation we utilized the Asahi Mark-J NMR-CT system, with a resistive vertical quadrupolar electromagnet (0.1 Tesla) and a proton resonance frequency of 4.5 MHz. Our main imaging methods are the inversion-recovery or IR, saturation-recovery, or SR, and calculated T/sub 1/. Difference, or D images, constructed by subtracting the data of the IR signal from that of the SR signal, have also been obtained in some cases. The system allows averaging of raw data. Hybrid images were constructed from two or more images to obtain clear definition of areas of interest. By using the hybrid image, several tissues of different relaxation times can be shown in the same image. Application in our study of the newly developed hybrid image indicates its importance in the detection and diagnosis of lesion, especially the detection of the differentiation of an edematous lesion from a tumor, and also abnormal fluid collection such as the pleural effusion or ascites. We hope that ...

International Nuclear Information System (INIS)

To evaluate the diagnostic accuracy of Fuji computed radiography (FCR) in the detection of interstitial pulmonary infiltrates, FCR life-size images at a pixel size of 0.1 mm were compared with conventional radiographs taken on the same day. Seventeen radiologists assessed the radiographs and FCR images of 56 cases, including 39 cases of various interstitial lung diseases such as interstitial pneumonia, pulmonary abnormalities associated with collagen disease, sarcoidosis, multiple pulmonary metastases, diffuse panbronchiolitis and pulmonary emphysema, and 17 normal controls. All of the pulmonary abnormalities were confirmed by high resolution CT. Observer performance tests were carried out using receiver operating characteristic analysis. In 21 cases of increased pulmonary density revealed by high resolution CT, FCR was significantly superior to conventional radiographs in the detection of reticular or linear shadows. In 11 cases of subtle ...

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Sixty-six cases of histologically proven hepatocellular carcinomas (HCC) were studied by MRI. Detectability was better by MRI than by CT, especially in the tumor under 2 cm in diameter. The capsule was detected in all cases of HCC over 3 cm in diameter. The capsule was able to be diagnosed only by dynamic MRI study in some cases. High intensity on the T1-weighted image and iso or low intensity on the T2-weighted image suggested that the nodule was adenomatous hyperplasi (AH) or well differentiated HCC. MRI is concluded to be an essential modality in the diagnosis of HCC. (author).

Science.gov (United States)

The aortovenous fistulas are rare, most of them are aortocaval fistula. The non-caval communication of the fistula is sparse. Herein we report a 47-year-old female diagnosed as traumatic aorto-superior mesenteric vein (Ao-SMV) fistula. The abdominal pain, fullness, and frank bruit on abdominal auscultation suggested the diagnosis of an intra-abdominal arteriovenous fistula. The diagnosis of Ao-SMV was further confirmed by the computed tomography (CT) and aortography. The fistula was successfully treated with transcatheter coil embolization. This is the first case of Ao-SMV fistula. It provides an alternative option of treatment other than conventional surgery. PMID:19327940

International Nuclear Information System (INIS)

Periosteal Ewing's sarcoma is an uncommon, but well documented origin of this malignant condition with radiography signs, different from intramedullary growing tumours. Imaging modalities like CT or MRI supply proof of macroscopically intact endosteal cortical surface and free medullary cavity in long bones affected by this periosteal type of malignancy. Definite confirmation is valid after a careful microscopic investigation of the resected specimen. The prognosis of this type of Ewing's sarcoma may be favourable than that of the central type. Early diagnosis and therapy are thus essential. A clinical survey of six observations is given. (orig.).

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Magnetic resonance imaging (MRI) of the lung is challenging because of substantial drawbacks. However, lung pathologies that are associated with increased attenuation values in CT enhance visualization in MRI: proton density is increased and tissue-air interfaces, resulting in susceptibility artifacts, are reduced in pneumonia, pneumonitis, edema, and carcinoma. On the other hand, many lung diseases result in shortness of breath, so that patients cannot hold their breath for long periods. Therefore, fast imaging techniques are required which should also allow for high spatial resolution so that small lesions can be detected. Calcifications and air pockets within lesions are not readily recognized with MRI. Thin section CT is standard for the diagnosis of pneumonia. With parallel imaging techniques, MRI examination of the lungs can be performed with short periods of breath holding, which allow for sub-centimeter resolution in the z-axis. ...