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At least 253 records · Page 14Linked to original sources
PubMed1997

Premature coronary artery disease associated with a disruptive mutation in the estrogen receptor gene in a man.

BACKGROUND: While estrogens protect against coronary artery disease in women, it is unclear whether they influence cardiovascular function in men. The present report describes coronary vascular abnormalities and the lipoprotein profile of a male patient with estrogen insensitivity caused by a disruptive mutation in the estrogen-receptor gene. METHODS AND RESULTS: Stress thallium scintigraphy, echocardiography, and electron-beam computed tomography (CT) scanning of the coronary arteries and detailed lipoprotein analysis were performed. Electron-beam CT scanning of the coronary arteries showed calcium in the left anterior descending artery. Lipoprotein analysis showed relatively low levels of total (130 mg/dL), LDL (97 mg/dL), and HDL (34 mg/dL) cholesterol; apolipoprotein A-I (91.7 mg/dL); and lipoprotein(a) (4.1 nmol/L), but normal levels of triglycerides (97 mg/dL) and pre-beta-1-HDL cholesterol (61 microg/mL). CONCLUSIONS: The absence of functional estrogen receptors may be a novel risk factor for coronary artery disease in men.

Adult↗
PubMed2006

A rural CT scanner: evaluating the effect on local health care.

OBJECTIVE: The first small rural hospital in Ontario to propose a computed tomography (CT) scanner was in Walkerton, a town 160 km north of London. The Ontario Ministry of Health approved the proposal as a pilot project to evaluate the effect on local health care of a rural scanner. This evaluation study had 3 parts: a survey of physicians, a survey of patients, and an analysis of population CT scanning rates. METHOD: The physicians in the area served by the scanner were asked about its impact on their care of their patients in a mailed questionnaire and in semistructured interviews. Scanner outpatients were given a questionnaire in which they rated the importance of its advantages. The analysis of scanning rates--the ratio of number of scans to estimated population--compared rates in the area with other Ontario rates before and after the scanner was introduced. RESULTS: The physicians reported that local CT allowed them to diagnose and treat patients sooner, closer to home, and with greater confidence. On average, 75% of the patients ranked faster and closer access as very important. Scanning rates in the area rose, although they did not match urban rates. CONCLUSIONS: The study confirms that the rural scanner changed the area's health care in significant ways and that it helped to narrow the gap between rural and urban service levels. We recommend that CT be expanded to other rural regions.

Attitude of Health Personnel↗
PubMed1999

Risk factors predicting recurrence in patients operated on for intracranial meningioma. A multivariate analysis.

The authors undertook a follow-up study of 286 patients who underwent surgical treatment for intracranial meningioma between 1973 and 1994, in order to analyse clinical, radiological, topographic, histopathological and therapeutic factors significantly influencing tumour recurrence. All patients were followed by using either computed tomography (CT) or magnetic resonance from 3 months to 17 years since first surgery (mean follow-up: 4.1 years). Forty-four (15.4%) recurrences were detected during this time period. Overall recurrence rates were 14%, 37% and 61% at 5, 10 and 15 years, respectively. Factors significantly associated with tumour relapse in bivariate analysis were: tumour location at petroclival and parasagittal (middle third) regions, incomplete surgical resection (assessed by Simpson's classification), atypical and malignant histological types (WHO classification), presence of nucleolar prominence, presence of more than 2 mitosis per 10 high-power fields, and heterogeneous tumour contrast enhancement on the CT scan. The multivariate analysis using the Cox's proportional hazards model identified the following risk factors for recurrence: incomplete surgical resection (Relative risk: 2.2; 95% Confidence interval: 1.33-3.64), non conventional histological type (RR: 2.13; 95%CI: 1-4.53), heterogeneous contrast enhancement on the CT scan (RR: 2.25; 95%CI: 1.1-4.72) and presence of more than 2 mitosis per 10 high-power fields (RR: 2.28; 95%CI: 0.99-5.27). Patients without any of these features showed low recurrence rates (4% and 18% at 5 and 10 years), and thus, they need less clinical and radiological controls through the follow-up than patients with some of these risk factors.

Adolescent↗
PubMed2006

Computer analysis of computed tomography scans of the lung: a survey.

Current computed tomography (CT) technology allows for near isotropic, submillimeter resolution acquisition of the complete chest in a single breath hold. These thin-slice chest scans have become indispensable in thoracic radiology, but have also substantially increased the data load for radiologists. Automating the analysis of such data is, therefore, a necessity and this has created a rapidly developing research area in medical imaging. This paper presents a review of the literature on computer analysis of the lungs in CT scans and addresses segmentation of various pulmonary structures, registration of chest scans, and applications aimed at detection, classification and quantification of chest abnormalities. In addition, research trends and challenges are identified and directions for future research are discussed.

Algorithms↗
PubMed1990

A comparison of in-house and regionalized computerized tomography scanning: clinical impact and cost.

Over a two-year interval, computerized tomography (CT) scans at an urban, 400-bed Department of Veterans Affairs medical center (VAMC) were obtained in three ways. First, an in-house low-efficiency machine was used. Then, scans were done at another area hospital, in effect duplicating some aspects of regionalizing services. Finally, a high-efficiency in-house machine was used. Clinical outcomes and costs of diagnosing 181 bronchogenic cancer patients were compared across the three time periods to identify any differences associated with regionalization of CT services. Patient groups were homogeneous with respect to sociodemographic characteristics, clinical presentation, and severity of disease. The first part of the analysis investigated whether the site of CT scanning affected clinical outcomes. Diagnostic procedures, surgical results, mortality, and length of stay were compared using one-way analysis of variance. Significant differences were found only for conventional tomography and CT utilization rates. While conventional tomography declined across the periods, CT utilization increased, exceeding national trends. The second part of the analysis examined the costs of CT scanning. During the regionalized period, the hospital paid a fixed fee of $519 per scan. Estimated costs of in-house scans were $285 in the low-efficiency and $141 in the high-efficiency periods. Charge-based payments made to the external facility and differences in the volumes of patients scanned internally account for the cost differences. The analysis showed that while regionalized CT scanning did not compromise the quality of care for these VA patients, it was more costly. Results suggest that VA hospital administrators should carefully consider ownership and payment arrangements when comparing regionalized and in-house provision of services.

Aged↗
PubMed1981

Correlations between CT scan and sensorimotor EEG rhythms in patients with cerebrovascular disorders.

Fifty subjects with cerebrovascular disorders and motor deficits, all able to perform a voluntary hand movement and aged between 33 and 78 years, were involved in this study. CT scan and computerized analysis of sensorimotor rhythms (mu rhythm and central beta rhythm) were performed for all patients. From the mu rhythm, the hemispheric asymmetry in amplitude and ERD during movement (ERD = event-related desynchronization) was measured and referred to a group of 38 neurologically normal subjects. Comparisons of CT scan data and EEG findings indicate a high correlation between morphological and functional findings. This correlation can be used to predict the localization of a lesion in the territory of the middle cerebral artery (MCA) based only on the amplitude and reactivity pattern of the mu rhythm. Thus, for example, an ipsilaterally enhanced mu rhythm in connection with a symmetric ERD indicates with a probability of 95% a deep, and with only 5%, a superficial lesion. Hemispheric mu amplitude symmetry and asymmetric ERD indicate a superficial cortical ischemia with a probability of 81%. An ipsilaterally attenuated mu rhythm accompanied by an asymmetric or abolished ERD indicates with 62% and 55%, respectively, a large extension of the infarct over the whole territory of the MCA.

Adult↗
PubMed1987

Pericerebellar fluid collections in infancy, sequelae of birth injury? A retrospective CT study.

Retrospective analysis of axial CT scans from 600 consecutive pediatric patients revealed 37 patients (6%) with abnormal low density pericerebellar spaces. Fourteen of these 37 patients (38%) were diagnosed as cerebellar atrophy, whereas 23 of the 37 patients (62%) were diagnosed as mass-like pericerebellar fluid collections. Detailed analysis of the morphology of these spaces suggests that the CT criteria proposed in this paper distinguish between (a) those low attenuation pericerebellar spaces that represent cisternal dilatation caused by cerebellar atrophy (Group I - Atrophy) and (b) those low attenuation pericerebellar spaces that represent low density mass-like collections of fluid which distort a relatively normal cerebellum (Group II - Collections). Analysis of the medical records of the patients in Group II - Collections reveal a high incidence of prematurity, developmental delay, difficult birth and head trauma, possibly indicating that such collections represent sequelae of birth.

Atrophy↗
PubMed1997

Localization of lesion in denial of hemiplegia after acute stroke.

BACKGROUND AND PURPOSE: Previous studies of lesion localization in dental of hemiplegia have often been confounded by factors such as the cerebral etiology, which aspects of the disorder are denied, and whether delusions are present. Our investigation focuses on denial of hemiplegia, without concomitant delusions, after cerebrovascular accident (CVA). METHODS: The CT scans of 30 patients with denial of hemiplegia after acute stroke were compared with those from 10 CVA patients with hemiplegia and visuospatial neglect but no denial. Lesion sites were detailed using the templates of Damasio and Damasio and, for the deep structures, those of Talairach and Tournoux. RESULTS: Analysis of the CT scans demonstrated that 26 of 30 denial patients had unilateral right-sided lesions and that this group showed a significantly higher incidence of lesions in deep white matter and the basal ganglia. CONCLUSIONS: The results are discussed in relation to recent ideas regarding the role of the basal ganglia and subcortical circuits in movement and executive function.

Aged↗
PubMed1995

Are pelvic computed tomography, bone scan and pelvic lymphadenectomy necessary in the staging of prostatic cancer?

OBJECTIVE: To investigate the effectiveness and economy of pelvic computed tomography (CT), bone scan and pelvic lymphadenectomy as staging modalities in patients undergoing radical prostatectomy. The use of prostate specific antigen (PSA) and Gleason's score as adjuncts to predict extracapsular disease were also evaluated and their economic implications examined. PATIENTS AND METHODS: Between January 1990 and June 1993, 861 men were newly diagnosed with prostate cancer, of whom 409 underwent surgery. All patients underwent pelvic CT scans and PSA analysis. Patients undergoing surgery had pre-operative bone scans and Gleason's scoring of their pathological tissue. RESULTS: Only 13 (1.5%) of 861 men had positive pelvic CT scans. Of the 409 patients who underwent surgery, all had negative pelvic CT and bone scans, and all underwent a modified pelvic lymphadenectomy; 192 (47%) had extracapsular disease. Only 15 (3.7%) patients who underwent surgery were found to have positive nodes. CONCLUSIONS: The use of pelvic CT and bone scans for clinical staging in patients with a PSA level of < or = 20 ng/mL should not be advocated because they have a very low yield and are not cost effective. We question the role of a modified pelvic lymphadenectomy for staging purposes, either by an open or laparoscopic procedure, because the yield of positive diagnoses is very low.

Bone Neoplasms↗
PubMed2004

De novo sarcoma of donor origin in a liver allograft determined by microsatellite analysis: a short report.

This case report describes a patient who underwent liver transplantation for HBV cirrhosis for hepatocellular carcinoma [corrected]. At 3.5 years post transplant, 6 cm tumor was found with CT scanning. With microsatellite analysis it was determined that the tumor was of donor origin. The patient underwent successful right hepatectomy of the tumor that proved to be sarcoma. The patient is doing well without recurrence 1.5 years after resection and 5 years post transplant.

Humans↗
PubMed2003

Clinical evaluation of a breathing protocol for PET/CT.

The aim of this study was to assess the frequency and severity of respiration-induced curvilinear respiration artifacts (RICA) on co-registered positron emission tomography/computed tomography (PET/CT) images acquired on a combined PET/CT scanner before and after modifying the respiration protocol for CT scanning, with retrospective analysis of two groups of 100 patients each, before and after implementing a respiration protocol with breath-hold (BH) in the normal expiration position for the acquisition of the CT images. The CT data were used as attenuation map and for image co-registration. A ranking of co-registered PET/CT and PET images (including maximum intensity projection) was done by two observers in consensus using a scale from 0 to 3. Zero indicated that no RICA was visible and 1, 2, and 3 described artifact with increasing severity. A significant difference in RICA occurrence was found between the two groups ( p<0.0001). There was a 45% decrease of artifact frequency when using the normal expiration protocol and a 68% decrease of grade-2 and grade-3 artifacts ( p=0.004). The results of this study suggest that BH during the normal expiration position for CT scanning can be recommended to reduce the occurrence and the severity of RICA on PET/CT.

Adolescent↗
PubMed1991

Correlation of early MRI with CT scan, EEG, and CSF: analyses in a case of biopsy-proven herpes simplex encephalitis.

Herpes simplex encephalitis (HSE) carries a high mortality rate. Therefore, an early diagnosis and institution of acyclovir are essential. We report a case of biopsy-proven HSE with 2 negative cerebrospinal fluid (CSF) analyses and 2 normal CT scans. However, MRI together with EEG were abnormal early in the disease stressing their significant role in any suspected case of HSE. Although brain biopsy remains controversial, CSF herpes simplex antigen detection offers hope in providing an early or retrospective diagnosis while specific antiviral therapy with acyclovir is initiated. Overdependency on routine CSF analysis or head CT scan can result in unnecessary delays in diagnosis and treatment.

Acyclovir↗
PubMed1993

Imaging strategies in the detection and evaluation of ARDS.

Considerable evidence has accumulated indicating that the chest radiograph is the most reliable imaging technique to evaluate the severity of lung edema in patients with established ARDS. Recently, the radiographic approach has been validated by direct comparison of an x-ray score of edema with the densitometric analysis of lung CT scan images. CT scanning may prove useful in quantitating the amount of residual healthy lung and in evaluating the effectiveness of PEEP in patients with acute respiratory failure. The application of CT scanning in these patients should be further expanded. Special effort should be made to evaluate unanesthetized, spontaneously breathing patients and to correlate CT quantitative data with the simultaneous analysis of portable chest radiographs in order to enhance the physician's ability to extract valuable, physiologic information from the chest film in critically ill patients. In order to improve the survival rate of patients with ARDS, methods are needed which detect ARDS at its earliest clinical stage. A number of radioisotopic techniques have been developed, based on the evaluation of the leakiness of the alveolar-capillary barrier either from the vascular or from the airspace side. Clearance of aerosolized DTPA from airspaces, although extremely sensitive, is not specific for ARDS in as much as factors other than lung injury may equally affect the rate of DTPA clearance from the lung. External detection of transvascular protein flux may serve as noninvasive means to assess the integrity of the lung microvascular endothelial barrier.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood-Air Barrier↗
PubMed2006

Regression and correlation analysis of preoperative versus intraoperative assessment of axes during navigated total knee arthroplasty.

OBJECTIVE: Modern computer assisted surgery (CAS) systems allow accurate positioning of the implants in navigated Total Knee Arthroplasty (TKA). However, when an operation is performed with a navigation system, it is important to know if the anatomical situation of the knee is reflected equally in both the preoperative image (e.g., CT) and the intraoperative navigation setup. In this study, we compared the preoperative anatomical situation to the virtual intraoperative situation of the navigation setup. MATERIAL AND METHODS: We analyzed 24 navigated operations. Intraoperatively, the condylar twist angle (CTA) was documented with the navigation system by measuring the angle between the transepicondylar axis (TEA) and posterior condyle axis (PCA). This data was compared with the preoperative data from the CT scan. RESULTS: Statistical analysis revealed that there was no correlation between the pre- and intraoperative data (r = 0.095). CONCLUSIONS: Statistically, there is no possibility of collecting the same angles and axes when using the two different methods (CT and navigation) on the same knee. It is not possible to copy the preoperative anatomical situation exactly with the virtual intraoperative data. Reasons for this include systematic errors, as well as inter- and intraobserver errors in both methods.

Arthroplasty, Replacement, Knee↗
PubMed1985

Detection of pulmonary metastases in patients with osteogenic and soft-tissue sarcomas: the superiority of CT scans compared with conventional linear tomograms using dynamic analysis.

A prospective serial evaluation in 19 patients with soft-tissue and osteogenic sarcomas was performed to determine whether computerized tomography (CT) or conventional linear tomography (LT) detected pulmonary metastases earlier. Analysis of the metastatic nodules was performed radiographically with histologic confirmation by obtaining serial CTs and LTs followed by metastasectomy. Nodules were classified as stable, growing, or developing and by detection on CT and/or LT. CT was the first positive study in a significantly greater number of patients (13 CT, 1 LT; P less than .005), and CT detected the nodules earlier than LT (56 CT first v 7 LT first; P less than .0001). Ninety of 166 nodules resected were detected by CT, LT, or both (54%). The median size of metastatic nodules documented at surgical exploration and first detected by CT was significantly smaller than that first detected by LT (7.6 mm for CT v 13.2 mm for LT; P less than .05). Of 55 histologically documented metastases detected initially either by CT or LT, CT was markedly superior to LT with 50 (91%) first detected only by CT (P less than .001). These data reveal that CT detects more pulmonary metastases earlier than LT and that developing or growing nodules in patients with sarcomas are usually metastases. Decisions regarding metastasis resection in sarcoma patients, therefore, should be based primarily on CT findings.

Adolescent↗
PubMed1998

Quantification of fracture healing with three-dimensional computed tomography.

Quantitative methods are necessary for an objective evaluation of fracture healing. Three-dimensional computed tomography (CT) for the measurement of callus volume and density could be such a method and was investigated in an animal model. In 23 goats a closed tibial fracture was created and stabilized with a cast. The animals were killed at 2, 4 and 6 weeks for radiographical, CT and biomechanical analysis. From the CT scans a three-dimensional reconstruction of the callus was made to measure its volume and mean density. At 2 weeks the callus volume had already reached its maximum. In contrast, callus density, torsional strength and torsional stiffness increased over time (P < 0.0001, analysis of variance, ANOVA). Multiple regression analysis showed that the callus volume was not related to the torsional properties. However, callus density was a significant explanatory variable for both torsional strength (R2 = 0.72, P < 0.0001) and torsional stiffness (R2 = 0.82, P < 0.0001). Therefore, callus density as measured by three-dimensional CT is a predictor of the extent of fracture consolidation. CT with three-dimensional reconstruction of the callus seems a valid technique for the quantification of fracture healing.

Analysis of Variance↗
PubMed1998

[Biomechanical analysis of occlusal splint therapy].

OBJECTIVE: The changes of the location and force of the condyle influenced by occlusal splint were investigated in order to know the biomechanical mechanism of occlusal splint therapy. METHODS: Auto-CAD technology, CT scanning, computer imaging analysis measurement and finite element method were separately used to comparatively analyze condylar position and its stress distribution in patients with temporomandibular joint disorders (TMD) treated with or without occlusal splint. RESULTS: Occlusal splint could lessen anterior space, in crease posterior and upper space in the temporomandibular joint (TMJ), so the condylar position move anterioinferiorly; the stress on condylar surface was lowered, mainly in anterior oblique surface or lateral side of condylar loading position; and the stress symmetry was bilaterally improved. OCCLUSION: The study suggests that regulating condylar position and improving the stress distribution is considered one of biomechanical mechanism of occlusal splint treatment.

Adult↗
PubMed2000

Computed tomography in the determination of transarticular C1-C2 screw length.

This study evaluated the significance of computed tomographic (CT) measurements of the upper cervical vertebrae and their clinical implications in transarticular C1-C2 screw placement. In the first part of the study, analysis of axial CT scans of the atlas of 46 patients who had a normal C1-C2 region was performed. Measurements included the vertical distance between the middle of the ventral cortex of the lateral mass and the anterior-most point of the anterior tubercle, and the angle of the anterior ring of C1 relative to the frontal plane. In the second part, axial CT scans of the upper cervical spine were performed in seven cadaveric cervical spines and analyzed using the same criteria. Using the Magerl technique of transarticular C1-C2 screw placement, one screw was placed in each cervical spine. Following each placement, a strict lateral radiograph was taken and the distance between the tip of the screw and the anterior-most point of the anterior tubercle of C1 was measured. Analysis of the cervical cadaveric specimens showed the vertical distance between the middle of the ventral cortex and the anterior-most part of the anterior tubercle when measured on CT scan corresponded to the distance measured on lateral radiographs after placement of the C1-C2 transarticular screw. The study of the 46 patients with normal C1-C2 region had shown the mean values of linear and angular measurements to be greater in males than in females, although no significant difference was found between the two groups (P>.05). The mean distance between the anterior-most point of the anterior tubercle and the middle of the ventral cortex of the lateral mass was 6.5+/-1 mm, and the mean transverse angle of the anterior ring relative to the frontal plane was 22 degrees+/-3.1 degrees. Axial CT evaluation of the individual anatomic relationships of the atlas is simple and may be a useful guide in the determination of the length of the transarticular screw when performed during surgery under lateral fluoroscopic control.

Adolescent↗