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At least 127 records · Page 7Linked to original sources
PubMed2005

Assessment of experimental osteoporosis using CT-scanning, quantitative X-ray analysis and impact test in calcium deficient ovariectomized rats.

INTRODUCTION: Osteoporosis is a major health problem in the elderly population particularly in postmenopausal women. Various techniques are currently available for detection and diagnosis of osteoporosis in humans, but not all of these can be used for evaluation of osteoporosis in animals. We assessed the feasibility and applicability of a spiral CT-scanning technique for use in evaluating bone loss in rats. In addition, we also tested the applicability of dispersive quantitative X-ray analysis (QXRA) coupled with scanning electron microscopy (SEM), and impact test to detect bone mineral content and biomechanical strength, respectively. METHODS: Twenty female Sprague Dawley rats were randomly assigned to sham operated or bilaterally ovariectomized groups and fed with a calcium-deficient diet for 16 weeks. Femurs and tibias were collected at termination. Using a spiral CT-scanner various cortical bone morphometric indices were measured in femurs. SEM-QXRA was used to quantify the calcium to phosphorus ratio (Ca:P) in regions of high bone turnover both in sham and CD-OVX rats. Tibias were subjected to the impact test for evaluation of biomechanical strength. RESULTS: Compared to sham operated rats, the CD-OVX animals had decreased combined cortical thickness (CCT), cortical area (CA), cortical area/periosteal area and radial density (RD), with increased medullary width and cross sectional areas as determined by CT-Scanning technique. SEM-QXR analysis indicates a decreased Ca:P ratio in the metaphyseal regions of distal femurs in CD-OVX rats when compared to sham-operated rats. The results of the impact test demonstrate lower threshold energy in tibias of CD-OVX rats compared to sham operated rats. DISCUSSION: The ability of these techniques to distinguish the bone characteristics of sham-operated rats from CD-OVX rats provides a methodological opportunity to assess osteoporosis in small animals like rats.

Absorptiometry, Photon↗
PubMed1992

Do metastases in vertebrae begin in the body or the pedicles? Imaging study in 45 patients.

We analyzed CT scans of the spine obtained in patients with vertebral metastases to determine what specific portion of the vertebra is initially involved by metastasis. The CT findings were then correlated with the abnormalities seen on plain films. Forty-five patients with histologically proved metastases in 95 vertebrae were included in the study. In all patients, CT scans and plain films of the spine were obtained within 1 week of each other. Analysis of the CT scans showed that the vertebral body was the portion of the vertebra that was most frequently destroyed by the metastases. Destruction of a pedicle was never identified in the absence of involvement of the body. The opposite was true on plain films, in which the most common finding was destruction of the pedicles. CT showed that the position of the metastases in the vertebra correlated with the sites of entry of the vertebral vessels. Our results show that the initial anatomic location of metastases within vertebrae is in the posterior portion of the body. Analysis of CT scans shows that the body is involved before the pedicles, although destruction of the pedicles is the most common finding on plain films. The pedicles are not the primary site of metastatic involvement. Destruction of the pedicles occurs only in combination with involvement of the vertebral body.

Adult↗
PubMed1995

Assessment of the dentate alveolar process with high resolution computed tomography.

The present study was undertaken to determine quantitatively the accuracy of modern high-resolution computed tomography (HR-CT) in imaging periodontal defects in vitro by means of comparative radiological and histological studies. The soft tissue and metallic restorations were removed from four mandibular and maxillary jaw segments. Eighteen lingual and buccal defects of different dimensions were artificially created over the roots of the teeth. Dental radiographs and 1.0 mm contiguous axial and coronal HR-CT scans were obtained. Histological specimens were prepared in the same plane as the CT scans. A quantitative analysis of the periodontal regions on the CT scans was feasible when the alveolar bone was 0.5 mm thick. A visible periodontal ligament space was found to improve the reliability of the measurement of buccal or lingual bone plates up to 0.2 mm thick or of the artificial dehiscences. In the axial HR-CT scans, 70% of the artificial defects could be identified. and in the coronal scans, 50%. In contrast, none of the defects could be evaluated on conventional dental radiographs. It is concluded that HR-CT scanning could be useful in assessing buccal and lingual alveolar bone morphology and in diagnosing larger dehiscences.

Alveolar Bone Loss↗
PubMed1991

[The role of the central nervous system in lupus erythematosus].

Central nervous system involvement of systemic lupus erythematosus was observed in 34 (36%) of the 94 patients studied between 1970-1990. A review of the diagnostic methods and therapy for central nervous system lupus is presented. The diagnosis of primary cerebral lupus was based on the history, physical examination and on the results of the cerebrospinal fluid analysis, CT-scan and EEG. Intractable headache (22/34), behavioural abnormalities (18/34), cranial neuropathy (16/34) occurred most frequently among neuropsychiatric symptoms. Immunoglobulin analysis of the cerebrospinal fluid proved to be the most sensitive method for detecting clinical activity (in 20/23). Central nervous system involvement was suggested by conventional serological test to a lesser degree. Alterations on CT scan and EEG were found in 17/27 and 14/26 of cases, respectively. IgM, IgA, and IgG indexes (indicators of intratechal immunglobulin synthesis) decreased when the central nervous system events subsided after successful treatment but the CT abnormalities (e. g. atrophy) were not altered.

Electroencephalography↗
PubMed1993

The role of three-dimensional computed tomography in the evaluation of acute craniofacial trauma.

Three-dimensional computed tomographic (3-D CT) reformations together with their corresponding conventional axial two-dimensional (2-D) CT images of 20 patients with facial fractures were compared with 2-D CT alone to define their usefulness in the determination of facial skeletal fracture patterns. Nine surgeons with three different levels of experience and training evaluated the presence and spatial arrangement of fractures in all 2-D CT and 3-D CT scans. Comparisons were made between their evaluations of 2-D CT alone and 2-D CT plus 3-D CT scans. Statistical analysis with Friedman's test were performed. The addition of 3-D CT did not alter the interpretation of 2-D CT in 75% of evaluations. The number and accuracy of the changes made with the aid of 3-D CT reflected the experience of the observers. Overall, there was no improvement in the accuracy of interpretations with the addition of 3-D CT.

Facial Bones↗
PubMed1990

Computed tomography of metastatic cervical lymph nodes. A clinical, computed tomographic, pathologic correlative study.

A retrospective comparative study of 63 neck dissections was undertaken to evaluate further the accuracy of high-resolution computed tomography (CT) in the detection of nodal metastases, as previous studies have indicated a trend toward the superiority of CT scanning over palpation. The respective values of neck examination, CT scanning, and histopathologic examination were assessed in 51 patients with head and neck cancer who underwent a total of 63 neck dissections. The overall agreement between clinical examination findings and histopathologic findings was 92% vs 81% for CT scanning. A retrospective analysis of the CT findings failed to reveal greater accuracy. We found nodes measuring 10 mm or more with central low density always to be malignant. Because CT scanning seems to offer little advantage over palpation in the nonirradiated neck, it should not be regarded as an essential tool in the staging of nodal disease. After radiation therapy, as neck dissection is only performed because of clinical or radiologic suspicion, CT scanning is of utmost importance.

False Negative Reactions↗
PubMed2001

Value of chest CT scans in routine ovarian carcinoma follow-up.

OBJECTIVE: The purpose of our study was to examine the role of chest CT scans in routine follow-up of patients who had been treated for ovarian carcinoma. MATERIALS AND METHODS: The radiologic follow-up of 127 women with metatastic ovarian carcinoma who had undergone surgery and chemotherapy between 1985 and 1996 was reviewed. In reviewing each patient's medical record, we determined whether a chest CT scan had been obtained, and if so, how many had been obtained during the patient's follow-up period. For patients with a chest CT scan, an analysis of the presence of disease in the thorax and its relation to disease in the abdomen and pelvis, as revealed on CT images, was performed. RESULTS: Of the patients whose cases were examined, 82 (65%) had had at least one chest CT scan obtained, with more than 50% having had three or more scans. Thirty-two (39%) patients had no radiologic evidence of disease. Twenty-eight (34%) showed disease in the abdomen or pelvis but no disease in the chest. Eighteen (22%) had both chest and abdominal or pelvic CT scans that indicated disease. In all of these patients, abdominal or pelvic disease had appeared on scans before spreading to the chest. Four (5%) of the patients had isolated chest disease. The rate of lung metastases from ovarian carcinoma in our series was 6%. In all of these patients, pulmonary metastases were preceded either by abdominal or pelvic disease or by a rise in tumor markers. CONCLUSION: Pulmonary metastases in ovarian carcinoma are rare and usually preceded by recurrence of carcinoma in the abdomen or pelvis. We suggest that chest CT scanning could be eliminated in the routine follow-up of patients who have been treated for ovarian carcinoma; yet it should be performed for those patients with elevated serum tumor markers but without evidence of abdominal or pelvic disease.

Adult↗
PubMed1987

Imaging-based stereotaxic serial biopsies in untreated intracranial glial neoplasms.

Forty patients with previously untreated intracranial glial neoplasms underwent stereotaxic serial biopsies assisted by computerized tomography (CT) and magnetic resonance imaging (MRI). Tumor volumes defined by computer reconstruction of contrast enhancement and low-attenuation boundaries on CT and T1 and T2 prolongation on MRI revealed that tumor volumes defined by T2-weighted MRI scans were larger than those defined by low-attenuation or contrast enhancement on CT scans. Histological analysis of 195 biopsy specimens obtained from various locations within the volumes defined by CT and MRI revealed that: contrast enhancement most often corresponded to tumor tissue without intervening parenchyma; hypodensity corresponded to parenchyma infiltrated by isolated tumor cells or in some instances to tumor tissue in low-grade gliomas or to simple edema; and isolated tumor cell infiltration extended at least as far as T2 prolongation on magnetic resonance images. This information may be useful in planning surgical procedures and radiation therapy in patients with intracranial glial neoplasms.

Adolescent↗
PubMed2004

Surgeon-directed ultrasound for trauma is a predictor of intra-abdominal injury in children.

This study investigated the efficacy of surgeon-directed focused assessment with sonography for trauma (FAST) in conjunction with physical exam (PEx) as a predictor of intra-abdominal injury in children. Injured children (ages < or = 17) presenting to a level I trauma center with abdominal trauma were evaluated in the emergency department (ED) by the trauma team of surgical attendings and residents. PEx and FAST were performed immediately upon arrival to the ED and results compared to CT, the standard exam for presence of intra-abdominal injury. Data was collected prospectively from July 1, 2000, until April 30, 2002. One hundred and twenty injured children underwent evaluation of abdominal trauma with PEx, FAST, and abdominal CT. Two patients had false-negative CT scans. Bayesian analysis was applied to the results of the remaining 118 patients. FAST compared with CT findings revealed sensitivity 70 per cent, specificity 100 per cent, positive predictive value 100 per cent, and negative predictive value 92 per cent. FAST results were combined with PEx findings such that either suggestive of intra-abdominal injury was regarded as a "positive exam." Sensitivity was 100 per cent, specificity 74 per cent, positive predictive value 53 per cent, and negative predictive value 100 per cent. Surgeon-directed FAST with consideration of PEx is a predictor of intra-abdominal injury in children.

Abdominal Injuries↗
PubMed2005

Reduction of organ motion in lung tumors with respiratory gating.

We evaluated the ability of a commercial respiratory gating system to assure the reproducibility of internal anatomy in respiration synchronized CT (RS-CT) scans. This passive system uses an infrared sensitive camera to track the motion of reflective markers mounted on the abdomen. Eighteen patients, nine with lung tumors and nine with liver tumors, were selected for evaluation of the Varian Real-Time Position Monitor respiratory gating system. Liver tumors were chosen as surrogate for lower lobe tumors. Each patient underwent at least two identical RS-CT scans, at end-inspiration (EI) or end-expiration (EE), to assess intra-fraction reproducibility. Twelve patients also underwent a free breathing scan and an opposed-respiration phase synchronized scan (EI if the two first were an EE and vice versa). On each CT, a physician contoured the liver, the kidneys, the spleen, and the diaphragms for the liver patients; and similarly, the lungs, the gross tumor volume (GTV), the trachea, the heart and the diaphragms for the lung patients. After registering the different CT images using bony anatomy, the changes of each structure between the respective data sets were quantified in terms of its volume, the displacement of its center of mass (COM), and an "index" coefficient of reproducibility. An analysis of the CT scans obtained at EI and EE phases yielded an average superior-inferior (SI) difference of the diaphragm position of 14.4 mm (range: 45.9-0.9). A similar analysis of CT scans acquired at the same breathing phase yielded 0.7 mm (range: 3.1-0, p=0.0001). Similar conclusions were derived in analysis of COM positions of the following structures: lungs, heart, lung's GTV, liver, spleen and kidneys. Evaluation of volume changes for lungs, liver, and spleen confirmed reproducibility of RS-CT while the "index" coefficient confirmed reproducibility of RS-CT of all organs. A commercial gating system using external markers for RS-CT significantly improves the positional reproducibility of thoracic and upper abdominal structures. This reproducible decrease in organ motion will allow a reduction of the margin of expansion facilitating increase in target dose beyond that allowed by conventional radiation treatments.

Adult↗
PubMed1994

Surgical management of hepatoma.

For the majority patients with HCC, the prognosis is poor. Only a fraction of patients will be resectable at the time of their diagnosis. For the oncologic surgeon caring for such patients, the challenges are multifaceted. First, he or she must have a familiarity with current imaging techniques and reliable support from a radiologist to determine whether a given patient can be technically resectable. We rely most heavily upon the initial diagnostic CT scan followed by the staging CTAP in order to define the resectable patient as clearly as possible. Additionally, the risk of postoperative hepatic failure must be assessed. Careful physical exam, blood chemistries, and volumetric analysis of CT scans demand much judgment on the part of the surgeon. While some patients are clearly capable of undergoing a resection, and others are clearly inoperable due to poor hepatic function, a large group of patients exist in a "gray area" where resection can be entertained but the risk of hepatic failure looms large. In this group the use of the ICG retention test or the 14C-aminopyrine breath test are occasionally useful. Further research into better assessment of hepatic reserve is clearly needed. Once a laparotomy is undertaken, IOUS is a key component of intraoperative staging and the final determinant of resectability. Resection itself must be performed with three goals: Resection of all disease with negative surgical margins, retention of as much hepatic parenchyma as possible in keeping with oncologic principles, and maintenance of hemodynamic stability with minimal transfusion requirements in an effort to minimize the stress of surgery. The combination of vascular control and the porta hepatis (and IVC where necessary), segmental hepatic resection where appropriate, and ultrasonic dissection can accomplish these goals. Intrahepatic recurrence, despite adequate resection, can be expected in many patients, and few will be candidates for a second resection. For this reason, and because most patients are unresectable at presentation, the oncologic surgeon must be familiar with palliative options available for his patients, as well as the surgical management of operable tumors. Close collaboration with one's colleagues in medical oncology, invasive radiology, and gastroenterology are critical to the optimal care of this difficult patient population.

Carcinoma, Hepatocellular↗
PubMed1995

[Diagnosis of cystadenomas and cystadenocarcinomas of the pancreas. Study of 35 cases].

OBJECTIVES: The aims of this study were to assess the circumstances of diagnosis and accuracy of imaging procedures in patients with cystic pancreatic tumours. METHODS: Thirty-five consecutive patients with cystic pancreatic tumours (serous cystadenomas: n = 19, mucinous cystadenomas: n = 9, cystadenocarcinomas: n = 7) were studied from 1988 to 1993. Respective diagnostic values of ultrasonography, endoscopic ultrasonography, CT scan and analysis of cyst fluid were evaluated. RESULTS: The circumstances of diagnosis were abdominal pain (74%), weight loss (23%), jaundice (8%), abdominal mass (6%), asymptomatic (6%). Initial diagnosis of cystadenoma was correctly made by ultrasonography, CT scan and endoscopic ultrasonography in 63%, 77% and 84%, and the type of cystadenoma was correctly diagnosed in 20%, 51% and 55%. A pseudocyst was falsely diagnosed in 28%, 12% and 3%, respectively. After blind review of CT scans and endoscopic ultrasonography records, the type of cystadenoma was correctly diagnosed in 82% by both procedures. Cytological examination of cyst fluid of 18 cystic tumours gave correct diagnosis in 10 cases with sufficient material. A low CEA (P < 0.002), Ca 19.9 (P < 0.003) and absence of mucins (P < 0.002) in cyst fluid was evocative of serous cystadenoma. CONCLUSIONS: Abdominal pain was the main circumstance of diagnosis in cases of pancreatic cystadenomas. The type of cystadenoma was correctly diagnosed in 82% by CT scan and endoscopic ultrasonography. Cytological examination, tumoural marker and mucin levels in cyst fluid were helpful for an accurate diagnosis of cystic tumours.

Adult↗
PubMedDate not supplied

Artifacts and thresholding in X-ray CT of a cortical bone and titanium composite.

PURPOSE: X-Ray CT has the potential to provide precise and accurate data from which the mechanical properties of bone can be calculated. Such data would be useful in understanding the response of bone tissue to implants. Various artifacts can, however, degrade accuracy of the data. The aim of this study was to measure the artifactual errors produced in CT of a simulated femoral bone-titanium composite and to propose a method to correct for them. METHOD: A composite phantom that simulates cortical bone and a titanium implant was designed and constructed. The phantom was scanned and the image data were analyzed over a range of thresholds with image analysis software developed for this study. The outer (OD) and inner (ID) diameter and the CT number of the cortical bone, with and without titanium, were measured over a range of cortical thicknesses. RESULTS: While ID can be accurately measured by choosing the proper threshold (800 HU), OD, even at optimal threshold, will be underestimated by approximately 2%. If a proper threshold is selected, CT number can also be accurately determined. Errors of up to 5%, however, are produced by titanium unless corrected by proper threshold selection. CONCLUSION: Intramedullary titanium is not a deterrent to obtaining accurate measurements of cortical bone dimensions and properties. Proper choice of thresholds for image analysis of CT scan data can yield accuracy and precision of < or = 2%.

Artifacts↗
PubMed2003

Smoking status, occupational asbestos exposure and bronchial location of lung cancer.

The objective of this study was to determine the factors associated with central airway versus peripheral bronchial location of lung cancer. All patients diagnosed with lung cancer from 1997 through 2000 in the Respiratory Disease Department of Rouen University Hospital were prospectively interviewed about their smoking and occupational history using a standardized questionnaire. All patients underwent white-light bronchial endoscopy using a 4.5 mm flexible endoscope. Tumors were classified as central when they were accessible and visible using this technique. Out of 217 cases of lung cancer included in this study, 155 (71%) were central. Histological type of lung cancer was strongly associated with bronchial location as central location was observed in 48, 82 and 92% of Adenocarcinoma (AC), Squamous Cell (SqC), and Small Cell Carcinoma (SCC), respectively (P<0.0001). Among non asbestos-exposed patients, location varied little with smoking status, with central location frequency ranging from 74 to 80%. In contrast, lung cancer was recorded central in 41% of long-term (> or =10 years) ex-smokers, 67% of short-term (<10 years) ex-smokers and 75% of current smokers (P=0.04) among patients exposed to asbestos, suggesting an interaction between duration of smoking cessation and occupational asbestos exposure with respect to lung cancer location. These findings were confirmed after adjustment for sex, age and histologic type in multivariate analysis. These results suggest that individually-tailored multimodality screening strategies relying on various combinations of low-dose CT scan, sputum analysis and fluorescence endoscopy according to each patient's profile may be more effective than standard strategies based on a single approach for all patients.

Adenocarcinoma↗
PubMedDate not supplied

Determining lung volume with three-dimensional reconstructions of CT scan data: A pilot study to evaluate the effects of expansion thoracoplasty on children with severe spinal deformities.

A retrospective review of a cohort of five patients who had been treated with a new technique for expansion thoracoplasty was performed. This study was designed to demonstrate that measurement of the volume of the lungs by three-dimensional reconstruction of CT scan data from children with complex spinal and thoracic deformities is a useful method for determining lung volumes in children who are too young to cooperate with pulmonary function testing. The authors' results indicate that lung volume by analysis of CT scan data is also a means of evaluating and quantifying the effects of expansion thoracoplasty. The authors were able to show that expansion thoracoplasty and stabilization with a titanium rib was able to increase the volume of lung parenchyma in the five patients in the study group by approximately 25% to 90% after surgical intervention.

Child, Preschool↗
PubMed1985

Acoustic tumors: preoperative measurement and correlation with postoperative facial nerve function.

The cases of 67 patients consecutively operated on for acoustic tumors are reported. Preoperative records consist of tumor size and the position of the fourth ventricle on computerized tomography (CT) scans. An analysis is made of the immediate postoperative and current function of the facial nerves. There is a statistically significant relationship between the number of weak or paralyzed seventh nerves and displacement of the fourth ventricle (P less than .05). It is now possible to accurately measure acoustic tumors on preoperative CT scans. The position of the fourth ventricle can also be clearly seen. The current standard of diagnosis and management of acoustic tumors should include a cursor measurement of tumor size on CT scan and a notation of the position of the fourth ventricle. Adoption of this method of reporting will permit meaningful evaluation of treatment for acoustic tumors. This analysis illustrates the importance of accurate measurements in reporting and evaluating surgical results.

Facial Nerve↗
PubMed2000

Physician utilization of a portable computed tomography scanner in the intensive care unit.

OBJECTIVE: To determine the utilization of a portable computed tomography (CT) scanner for critically ill adult patients in an intensive care unit (ICU). DESIGN: Survey study and retrospective review. SUBJECTS: Critical care attending staff and fellows and neurosurgery residents. SETTING: A university hospital and Level I trauma center with a multitrauma ICU, a neurotrauma ICU, and a neurosurgical ICU. INTERVENTIONS: We surveyed all physicians who ordered portable CT scans from December 1996 through June 1998. Ordering physicians included critical care attending staff and fellows (anesthesiology, surgery, internal medicine) and neurosurgery residents. Physicians who no longer worked at the institution were contacted by mail or fax. Radiology records were reviewed to determine the actual number and type of scans performed. MEASUREMENTS AND MAIN RESULTS: The survey response was 100%. Most physicians reported ordering portable head CT scans (97%), followed by chest CT (88%), abdominal CT (78%), and pelvic CT (34%) scans. Analysis of the actual number of scans performed correlated with these reports (511 head, 115 chest, 88 abdomen, and 87 pelvis). The indication for portable CT scans (as opposed to a "fixed" or "stationary" scans) cited most often was patient severity of illness (77%). Patients on extracorporeal support (93%), those with cardiovascular instability (70%), followed by those with respiratory instability (57%) and neurologic instability (40%) were deemed too ill to transport. If the portable CT scanner was unavailable, however, most physicians (67%) ordered a fixed helical CT scan and the patient was transported to the radiology suite, regardless of medical condition. CONCLUSIONS: Access to a portable CT scanner impacts the physician ordering patterns for ICU patients. We found that 100% of surveyed physicians used the portable CT scanner for critically ill patients when the patient was unstable. If the diagnostic study was deemed medically necessary, and the portable scanner was unavailable, most surveyed physicians ordered a "fixed" helical scan and the patient was transported by an experienced transport team for the study. The portable CT offered an alternative and potentially safer means of obtaining diagnostic studies.

Attitude of Health Personnel↗
PubMed1998

Clinical significance of acute traumatic intracranial pneumocephalus.

Among 1142 patients with head injuries hospitalized in the Neurosurgery Department of Gazi University Medical School during the period between 1979 and 1992, 583 had initial CT scans. A retrospective analysis of these initial CT images revealed intracranial air on admission in only 21 cases. These were classified as acute traumatic intracranial pneumocephalus: a potentially serious complication of head injury. CT scans were re-evaluated so as to reveal whether air was situated in the epidural, subdural, or subarachnoid spaces or intracerebrally; whether associated space-occupying lesions were present and whether the air bubbles were single or multiple. Clinical data such as the presence of persistent rhinorrhea and/or otorrhea, tension pneumocephalus, severity and type of trauma, and outcome were were also assessed to determine the significance of this rare finding.

Adolescent↗