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At least 109 records · Page 6Linked to original sources
PubMed1990

Morphologic changes in the body of the pancreas secondary to a mass in the pancreatic head. Analysis by CT.

CT scans of 279 normal subjects and 78 patients with a pancreatic head mass were reviewed. The mean width of the pancreatic body in normal subjects was 15.8 +/- 2.9 mm, but the width decreased with age. The pancreatic head to body width ratio (H/B ratio) was constant (1.45 +/- 0.03). In 56 patients with carcinoma, the pancreatic body width decreased as tumor size increased and uniform atrophy with continuous beading duct was common in large carcinomas. The H/B ratio in small carcinomas (less than 2 cm), however, was significantly smaller than normal (p less than 0.05) and an enlarged pancreatic body was seen in 55 percent of these cases. The pancreatic body width in focal inflammatory masses was large compared to that in carcinomas of comparable size; the H/B ratio (1.57) was close to normal and the duct caliber to gland width ratio was low (0.16), even with large lesions. Non-uniform pancreatic body with discontinuous duct was most commonly associated with pseudocyst. Characterization of the CT appearance of secondary changes in the pancreatic body may help to improve the diagnosis of pancreatic head mass.

Adult↗
PubMed1990

[CT scans in the diagnosis of cerebellar hemangioblastomas. Analysis of 21 cases].

Computed tomography (CT) scans in 21 patients with pathological verified cerebellar hemangioblastoma were analysed. There were 14 cases of cystic nodular pattern, 4 cases of nodular pattern and 3 cases with the pattern of cyst only in this series. The characteristic features of hemangioblastomas on the CT scans usually consisted of large circumscribed cystic low density lesions with a small enhanced nodule in each of them. On surgical operations 20 cases in this series were classified to be of cystic-nodular pattern. In order to show the cystic-nodular pattern in a better manner on the CT the thin slice CT scan 5 should be recommended in addition to the use of an appropriately increases amount of intravenous contrast medium when hemangioblastoma of the cerebellum would be suspected.

Adolescent↗
PubMed1979

Statistical detection of nonvisible isodense subdural fluid collections.

An analytic method for detecting isodense subdural fluid collections from computed tomography (CT) scan pixel attenuation data is presented. Analysis of 44 CT scan levels from 8 patients with isodense subdural hematomas (ISDH) and 50 CT scan levels from 15 patients without ISDH indicates 6% false positive and 3% false negative errors if the analysis is restricted to noncontrast CT scans that demonstrate subcalvarial bilateral cortical attenuation symmetry in the pictorial display.

Atrophy↗
PubMed1988

Peritumoral brain edema associated with meningiomas.

Although generally benign, meningiomas may be associated with extensive peritumoral brain edema, as visualized on computed tomographic (CT) scans. An analysis of 38 meningiomas indicated that severity of edema on CT scans positively correlated with tumor size and also with evidence of disruption of the cortical layer, which initially separates the tumor from the white matter, in which edema tends to accumulate. The various histological subtypes also seemed to be distinct in their tendency to induce edema, with the transitional and meningotheliomatous subtypes associated with the more severe grades of edema. There was no correlation between grade of edema and location of the tumor. Contact of the edematous area or the tumor itself with the ventricle, which is relevant to the possibility of drainage of edema fluid into the ventricle, seemed to occur in cases of the more severe grades of edema rather than in cases showing slight or no edema.

Brain Edema↗
PubMed2002

The radiological anatomy of the anterior skull base.

Two complications dominate the thoughts of any surgeon undertaking functional endoscopic sinus surgery (FESS), namely damage to orbital structures and fractures of the fovea ethmoidalis. To avoid these complications, a detailed knowledge of the paranasal sinus anatomy of the patient is essential. This is usually assessed using preoperative computerized tomography (CT) scans of the paranasal sinuses. Analysis of 151 CT scans, measuring the height of cribriform plate below a supraorbital horizontal and above the hard palate was performed. Variation of shape and take-off angle of the fovea ethmoidalis was also measured. Comparison between left and right sides, and between scans showing radiological features of sinonasal disease and normal scans, was undertaken. Five patterns of fovea ethmoidalis were identified. No statistically significant difference between left and right sides was demonstrable for any parameter, irrespective of pathological status.

Ethmoid Bone↗
PubMed2004

Lung cancer screening--where we are in 2004 (take home messages).

The best prognosis for lung cancer can be expected by diagnosis at an early stage of the disease. Long-term survival may be improved by increasing the number of early-stage diagnoses. At the present time, three different screening tools for lung cancer are available: Low-dose CT scanning, sputum analysis and fluorescence bronchoscopy. Each of these tools has a different screening target. Low-dose CT scanning focusses on small pulmonary nodules, sputum analysis has the potential of detecting lung cancer of the central airways, and fluorescence bronchoscopy can identify pre-malignancy, carcinoma in situ and minimally invasive squamous cell carcinoma. The best way forward appears to be a combination of all techniques. Sputum analysis can be used to define a better-characterised risk population, and subsequently this population can undergo low-dose CT and fluorescence bronchoscopy.

Bronchoscopy↗
PubMed2001

Predictive value of bone mineral density and morphology determined by peripheral quantitative computed tomography for cancellous bone strength of the proximal femur.

Peripheral quantitative computed tomography (pQCT) is an established diagnostic method for assessment of bone mineral density in the diagnosis of osteoporosis. However, the capacity of structural parameters of cancellous bone measured by high-resolution computed tomography remains to be explored. In 33 patients, bone mineral density (BMD) of the proximal femur was measured in vitro by pQCT using cylindrical biopsies from the intertrochanteric region harvested before the implantation of an artificial hip joint. By digital image analysis of CT scans, parameters derived from histomorphometry describing the microarchitecture of cancellous bone were measured. The biopsies were also loaded to failure by an uniaxial compression test to determine the biomechanical parameters, Young's modulus, strength, and maximum energy absorption (E(max)). Strong correlations were found for BMD vs. mechanical parameters (r = 0.73 for Young's modulus, r = 0.82 for strength, and r = 0.79 for E(max); p < 0.001, n = 29). The morphological parameters, bone volume per trabecular volume (BV/TV), apparent trabecular thickness (app.Tb.Th), apparent trabecular separation (app.Tb.Sp), and trabecular number (Tb.N), correlated significantly with all mechanical parameters. The combination of morphological parameters with BMD in a multivariate regression model led to an overall, but only moderate, increase in R(2) in all cases. Our data confirm the high predictive value of BMD for the mechanical competence of cancellous bone of the intertrochanteric region. However, quantification of cancellous bone structure by image analysis of CT scans may provide additional qualitative information for the analysis of bone strength.

Aged↗
PubMed2005

[Development and study of three-dimensional CT scanning system for dental cast measurement and analysis].

OBJECTIVE: To develop a computer assisted CT scanning system for 3D dental cast measurement and to study its reliability. METHODS: 20 dental stone casts were scanned by helical CT and captured a series digital sliced radiographs of them. The program which was developed by Visual C 6.0 language and run under the Windows surroundings rebuilt the 3D graphics and measured the coordinate of the dental cast. These dental casts were scanned and measured to test the reliability of the system, contrasting with manual measurement. RESULTS: There was no significant difference between 3D CT scanning and manual measurement (P > 0.05). CONCLUSION: The system is a valuable computer assisted system for clinical diagnosis and treatment of malocclusion.

Humans↗
PubMed1997

Computed tomography scanning and delirium in elder patients.

OBJECTIVE: 1) To examine the ordering of head CT scans in elder patients with delirium and cognitive impairment; and 2) to report CT scan findings associated with these conditions. METHODS: This was a 2-part study. Part 1 was a prospective, observational study of 560 adults > 70 years of age evaluated at 3 separate EDs using a 200-hour stratified sampling process at each ED. During Part 1, the frequencies of specific findings (i.e., delirium, impaired consciousness, and impaired cognition) and CT scan rates for these groups were determined. Part 2 was a retrospective analysis of CT scan reports and medical records (n = 279) for patients > 70 years of age in the prospective sample (n = 79) and from a sample (n = 200) of CT scans obtained at a fourth ED. Part 2 examined clinical findings detected in the ED to determine those factors that were associated with acute findings on CT scan. RESULTS: Part 1: There were 333 (59.4%) patients prospectively classified as having impaired cognition, impaired consciousness, or delirium; 79 (23.7%) of these patients had a head CT scan. Of these 3 groups, delirious patients were more frequently scanned (p < 0.001). Part 2: Of 279 CT scans, 42 (15.0%) were positive for an acute condition (hemorrhage, hematoma, space-occupying lesion, infarct). Of 42 positive scans, 40 (95.1%) were found in the 102 (36.6%) patients with either impaired consciousness or a new focal neurologic finding detected in the ED. CONCLUSIONS: Considerable variability in ED CT scan ordering exists for elder patients with neurologic findings. Impaired consciousness and/or new focal neurologic signs are associated with acute findings on CT scan in elder patients. Acute CT abnormalities are uncommon in elder ED patients with other neurologic findings. Additional prospective evaluation is warranted prior to guideline development for CT scans in this patient population.

Acute Disease↗
PubMed1981

Low-dose CT scanning for quantitative spinal mineral analysis.

The effect of x-ray exposure on the precision of quantitative CT bone mineral measurements was determined using excised vertebrae and phantoms. Specimens were scanned at 80 kVp with exposures ranging from 23 to 380 mAs using the UCSF/GE research scanner, a modified GE CT/T 7800. Dose was measured using thermoluminescent dosimeters. A patient exposure of 100 mrem (10(-3) Sv) was judged adequate to provide useful quantitative vertebral mineral measurements with this scanner.

Humans↗
PubMed1981

Improved confidence of outcome prediction in severe head injury. A comparative analysis of the clinical examination, multimodality evoked potentials, CT scanning, and intracranial pressure.

An analysis of clinical signs, singly or in combination, multimodality evoked potentials (MEP's), computerized tomography scans, and intracranial pressure (ICP) data was undertaken prospectively in 133 severely head-injured patients to ascertain the accuracy, reliability, and relative value of these indicants individually, or in various combinations, in predicting one of two categories of outcome. Erroneous predictions, either falsely optimistic (FO) or falsely pessimistic (FP), were analyzed to gain pathophysiological insights into the disease process. Falsely optimistic predictions occurred because of unpredictable complications, whereas FP predictions were due to intrinsic weakness of the indicants as prognosticators. A combination of clinical data, including age, Glasgow Coma Scale (GCS) score, pupillary response, presence of surgical mass lesions, extraocular motility, and motor posturing predicted outcome with 82% accuracy, 43% with over 90% confidence. Nine percent of predictions were FO and 9% FP. The GCS score alone was accurate in 80% of predictions, but at a lower level of confidence (25% at the over-90% level), with 7% FO and 13% FP. Computerized tomography and ICP data in isolation proved to be poor prognostic indicants. When combined individually with clinical data, however, they increased the number of predictions made with over 90% confidence to 52% and 55%, respectively. Data from MEP's represented the most accurate single prognostic indicant, with 91% correct predictions, 25% at the over-90% confidence level. There were no FP errors associated with this indicant. Supplementation of the clinical examination with MEP data yielded optimal prognostic power, an 89% accuracy rate, with 64% over the 90% confidence level and only 4% FP errors. The clinical examination remains the strongest basis for prognosticating outcome in severe head injury, but additional studies enhance the reliability of such predictions.

Adult↗
PubMed2003

Hematuria as an indicator for the presence or absence of urinary calculi.

The purpose of this study was to determine whether the presence of hematuria or its absence can predict the presence or absence of urinary calculi as determined by computed tomography (CT) scan in patients presenting to the ED with acute abdominal colic. We reviewed the urine analysis and CT scans of all patients presenting to the ED over a 12-month period with acute colic and a clinical suspicion of urinary calculi. Urine samples were drawn on arrival in the ED before CT scanning. Two hundred seventy-seven patients were included in the study. The prevalence of urinary stones as detected by CT was 57.4%. The positive predictive value, negative predictive value, and accuracy for hematuria as a marker for stone disease was 60.9%, 72.4%, and 62.1%, respectively. A total of 3.24% of patients had some degree of obstruction, all of whom had hematuria. The absence of hematuria is not a reliable exclusion criterion for urinary calculi. The detection of urinary stones without hematuria does not imply obstruction.

Biomarkers↗
PubMed2005

Computerized analysis of mesothelioma on CT scans.

Computed tomography (CT) has become an essential tool for monitoring the progression of mesothelioma tumor or a patient's response to treatment. Despite the accepted role of CT for the evaluation of mesothelioma, however, the current standard practice remains the manual measurement of tumor extent on CT scans. The process of manual measurement acquisition is tedious and subject to inconsistency. We have quantitatively assessed the variability of manual mesothelioma measurements both in baseline CT scans and in the context of tumor response classification across temporally sequential scans. To facilitate the acquisition of mesothelioma measurements, we have developed and evaluated computerized methods for the assessment of mesothelioma tumor thickness on CT scans; we anticipate that such computer-assisted approaches will make the radiologic assessment of mesothelioma more efficient, thus facilitating the establishment of improved clinical protocols.

Body Weights and Measures↗
PubMed2006

Prediction of torsional failure in 22 cadaver femora with and without simulated subtrochanteric metastatic defects: a CT scan-based finite element analysis.

BACKGROUND: In metastatic bone disease, prophylactic fixation of impending long bone fracture is preferred over surgical treatment of a manifest fracture. There are no reliable guidelines for prediction of pathological fracture risk, however. We aimed to determine whether finite element (FE) models constructed from quantitative CT scans could be used for predicting pathological fracture load and location in a cadaver model of metastatic bone disease. MATERIAL AND METHODS: Subject-specific FE models were constructed from quantitative CT scans of 11 pairs of human femora. To simulate a metastatic defect, a transcortical hole was made in the subtrochanteric region in one femur of each pair. All femora were experimentally loaded in torsion until fracture. FE simulations of the experimental set-up were performed and torsional stiffness and strain energy density (SED) distribution were determined. RESULTS: In 15 of the 22 cases, locations of maximal SED fitted with the actual fracture locations. The calculated torsional stiffness of the entire femur combined with a criterion based on the local SED distribution in the FE model predicted 82% of the variance of the experimental torsional failure load. INTERPRETATION: In the future, CT scan-based FE analysis may provide a useful tool for identification of impending pathological fractures requiring prophylactic stabilization.

Aged↗
PubMed1990

Hyperdense middle cerebral artery sign on CT: efficacy in detecting middle cerebral artery thrombosis.

The hyperdense middle cerebral artery sign is a CT predictor of the development of a large cerebral infarct. The limits of detectability were tested in a blinded, then unblinded analysis of CT scans from 25 acute stroke patients. In the initial blinded analysis, sign detection exhibited the following mean values: sensitivity, 78.5%; specificity, 93.4%; positive predictive value, 66%; negative predictive value, 96.4%; accuracy, 91.3%. Kappa statistics analysis indicated poor interobserver agreement (k = .38). Results of unblinded analysis were as follows: sensitivity, 69%; specificity, 94.4%; positive predictive value, 82.8%; negative predictive value, 88.7%; accuracy, 87.3%. There was fair unblinded interobserver agreement (k = .53). Unblinded analysis had a lower false-positive frequency and did not increase the number of true-positive determinations. We conclude that detection of the hyperdense middle cerebral artery sign on CT scans by multiple observers is a sensitive, accurate, and predictive indicator of middle cerebral artery thromboembolism.

Acute Disease↗
PubMed1990

Neurotoxicity of iohexol vs iopamidol in lumbar myelography. Clinical, electrophysiological and brain CT scan correlations.

The potential neurotoxicity of iohexol and iopamidol in lumbar myelography was investigated in 20 patients using three criteria: clinical symptoms, EEG recordings with spectral analysis and CT scans of the brain. There was no significant difference in clinical side-effects between the two groups (Iopaminol, Iohexol). In 10 patients (iopaminol 4, iohexol 6) CT scans revealed an important penetration of the contrast media into the subarachnoid spaces at 3 hours and into the cerebral cortex at 24 hours. This cerebral contamination was unrelated to the headaches experienced by the patients or to the electrophysiological disturbances observed. Spectral analysis in brain-contaminated subjects showed a reduction of delta, beta 1 and beta 2 bands with iohexol. This reduction suggests that EEG activation is less pronounced with this agent than with iopaminol.

Brain↗
PubMed2001

Volumetric computerized tomography as a measurement of periprosthetic acetabular osteolysis and its correlation with wear.

Osteolysis, which is considered to be a major source of morbidity following total hip joint replacement, has been notoriously difficult to measure accurately, particularly in the acetabular area. In order to study periacetabular osteolysis, specialized software for computerized tomography (CT) scan image analysis has been developed. This software (3D-CT) eliminates metal artifacts, allows three-dimensional segmentation of the CT image, and reconstructs the segmented image to provide an accurate representation and measurement of volume for osteolytic lesions. In the present study, 20 patients underwent periacetabular osteolytic volume determination using 3D-CT, functional assessment (using the Harris Hip Scale, the Western Ontario and McMaster University Osteoarthritis Index, and the short form 36 questionnaire), and two-dimensional analysis of volumetic polyethylene wear using digitalized plain films. Periacetabular osteolysis correlated directly with the polyethylene wear rate (relative risk [RR] = 0.494, P = 0.027). If one patient with an acetabular revision, one patient with recurrent dislocation, and one patient with a Biomet prosthesis are excluded, then the correlation between wear and osteolysis is improved (RR = 0.685, P = 0.002). In summary, the current study demonstrates both the feasibility of CT imaging of periacetabular osteolysis and the correlation between polyethylene wear and osteolytic volume, providing a potential outcome measure for clinical trials that are designed to examine interventions in this complex disease process.

Acetabulum↗
PubMed2003

Botulinum toxin type A treatment for contouring of the lower face.

BACKGROUND: Since type A botulinum toxin was first reported for the treatment of masseter muscle hypertrophy in 1994, there have been few reports about cosmetic indications for contouring procedures of the lower face with injection of botulinum toxin type A, and this procedure remains unpredictable. OBJECTIVES: This study attempted a quantitative prospective analysis of reduction of masseter muscle hypertrophy after Botox injection, using ultrasound and computerized tomography (CT) scans to analyze the possible use of botulinum toxin type A as a contouring procedure for the lower face. METHODS: Forty-five patients consented to the study and received a contouring procedure of the lower face from November 2001 to April 2002. Twenty five to 30 U of Botox per side was injected at five to six points into the prominent portions of the mandibular angle. Serial measurements were made of the thickness of the masseter muscle by ultrasound and CT before the injections and at 1 and 3 months thereafter. A quantitative analysis for the masseter thickness changes was performed on just one patient who underwent all ultrasound and CT scans. Statistical analysis of the masseter thickness change was by two-way and multiple comparison analysis. To evaluate clinical long-term effects, the patient's satisfaction with the procedure and any side effects after injections were monitored during 4 to 10 months of follow-up. RESULTS: Among the total of 45 patients, 15 underwent the three ultrasound measurements, and 14 had the three CT measurements. With regard to quantitative analysis of the thickness change to the masseter on both sides of the face according to time points, this was gradually reduced by both the ultrasound and CT measurements during the first 3 months. By ultrasound, the maximum reduction in masseter thickness was seen 1 month after the injections, with a slight increase being observed at 3 months after injection. A continued reduction of masseteric muscle thickness was seen on the CT up to 3 months after injection. In terms of patient satisfaction for up to 10 months of follow-up, the results were as follows: very satisfied, 1; satisfied, 36; slight improvement, 3; no change or dissatisfied, 5. Main local side effects included masticatory difficulties, muscle aching at injection sites, and speech disturbance. However, these side effects were transitory, usually lasting from 1 to 4 weeks after the injections. CONCLUSIONS: Preliminary results from this study suggest that an injection of Botox resulted in relatively satisfactory clinical effects, although there was only a short-term follow-up. It is suggested that the use of botulinum toxin type A for contouring of the lower face can be established as a simple, predictable, alternative facial contouring procedure without a prolonged recovery time.

Adult↗