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PubMed1984

Discrimination between thorotrast and iodine contrast medium by means of dual-energy CT scanning.

A dual-energy CT scanning method is proposed to discriminate between thorotrast and iodine contrast medium in patients suspected of having thorotrast deposits in the spinal canal as a consequence of myelography injections. The ratio of CT numbers at two X-ray tube voltages was used to distinguish the two materials in the analysis of dual-energy CT scanning. The K-edge of thorium was used to enhance the discrimination sensitivity. Theoretical analysis predicted the feasibility of the method and this was verified by experiment. The sensitivity for the discrimination between thorium and iodine is much higher than that achieved by the gamma-ray counting technique using a whole-body counter. This method, the ratio of CT numbers at two kV values, may be useful in other clinical applications.

Body Burden↗
PubMed1996

Analysis of interobserver disagreement in the assessment of subarachnoid blood and acute hydrocephalus on CT scans.

The purpose of this study was to analyse factors for interobserver disagreements in two scales used for the assessments of the amount of blood in subarachnoid space (Fisher grading) and of acute hydrocephalus on computerized tomographic (CT) scans. The assessments made by four neuroradiologists on 59 CT scans obtained in the acute stage after subarachnoid hemorrhage were analysed by a statistical method by Svensson and Holm. This method permits the separation of the inter-observer disagreements in their random and systematic components. The overall consistency of the assessments was significant (p < 0.0005) but the neuroradiologists disagreed on half of the CT-scans. The kappa values were 0.50-0.63. The analysis showed that the main reason for disagreements was systematic inter-observer differences in their use of the clinically most important parts of staging, i.e. subarachnoid clot or intraventricular blood (Fisher grading) and too low categories (hydrocephalus). The main conclusion from this study is that the proper remedy for Fisher grading and for grading of hydrocephalus is a sharpening of the criteria of specific category levels and given this improvement both grading systems will show a high level of reliability.

Data Interpretation, Statistical↗
PubMed2005

Radiograph-based femur morphing method.

Many applications in orthopaedic surgery require the creation of personalised design models that can serve as the basis for navigation in computer aided surgery systems or be used to create a personalised model to perform structural analysis during pre-operative planning or post-operative follow-up. The paper introduces a method for developing a three-dimensional (3D) patient-specific model of a femur bone from an antero-posterior radiograph. A generic femur was employed and was altered on the basis of bone boundaries visible on radiographs. Morphological errors were evaluated against 3D models obtained from computed tomography (CT) scans. When only the antero-posterior radiograph was used, the average radius estimation error was 4.8 mm, the average percentage area estimation error was 14%, and the average percentage estimation error for inertial moments was 15%. If both the medial-lateral and the anterior-posterior radiographs were used, these errors were 2.0 mm, 5% and 7%, respectively. The procedure described can be profitably employed whenever CT scans are not available, such as during a retrospective analysis, or when CT scans cannot be justified because of X-ray exposure and cost considerations.

Femur↗
PubMedDate not supplied

Comparison between magnetic resonance imaging and other techniques in 39 multiple sclerosis patients.

Till now there are no specific laboratory tests to confirm the diagnosis of Multiple Sclerosis (MS). For this reason the diagnosis of MS is based on the clinical evidence of central nervous system white matter disease with temporal and spatial dissemination of the lesions. Recent advances in neurophysiology and imaging techniques can provide more objective criteria towards more accurate and earlier diagnosis, detecting clinically unsuspected lesions. We evaluated 39 MS patients (23 definite, 7 probable, 9 possible) by Magnetic Resonance Imaging (MRI), CT scan, Evoked Potentials (EPs) testing and Cerebrospinal Fluid analysis. MRI was abnormal in 34 cases (87%) and CT scan in 14 (36%); EPs were also abnormal in 34 cases. 30 patients had both EPs and MRI alterated and 4 patients had alterated only one of the two investigations. The frequency of EPs alterations was: VEP 74%, Median SEP 44%, Tibial SEP 59% and BAEP 54%. The BAEP was more sensitive than MRI in detecting brainstem involvement. On the other hand MRI was more sensitive than SEPs in detecting somatosensory pathways involvement. The combined use of the two techniques allowed a reclassification of 10 out of 16 possible or probable MS cases.

Adult↗
PubMed2006

An unusual case of bowel perforation due to fish fin ingestion.

We reported the case of an 85-year-old woman who presented with an acutely tender abdomen and underwent abdominal computed tomography (CT) scanning initially reported as showing diverticulitis. After failed conservative management, this patient was taken to theatre, and laparotomy revealed a punctate perforation of the ileum due to a 4 x 3 cm fish fin, which was removed through enterotomy. Retrospective analysis of the initial CT scans showed a foreign body consistent with that removed. This is the first case documented in the literature of perforation of bowel due to fish fin ingestion, as opposed to fish bone. It highlights firstly how common presentations may have an uncommon cause and secondly, how easily a small foreign body can be missed on CT scan. It also highlights and the importance of (i) eliciting a full history of eating habits in those presenting with abdominal pain and (ii) basing intervention on clinical findings. In this case report, we review the wider medical literature on perforation due to foreign body ingestion.

Aged, 80 and over↗
PubMed2002

Early prediction of acute pancreatitis: prospective study comparing computed tomography scans, Ranson, Glascow, Acute Physiology and Chronic Health Evaluation II scores, and various serum markers.

The aim of this study was to assess the predictability of the outcome of acute pancreatitis using the Ranson, Glascow, and Acute Physiology and Chronic Health Evaluation (APACHE) II scores, the computed tomography (CT) scan, and several serum markers. Altogether, 137 consecutive patients with acute pancreatitis confirmed by CT scan were prospectively included. Blood samples were obtained daily for 6 days. The predictive value of each parameter was studied by univariate and multivariate analyses comparing mild and severe pancreatitis. A total of 111 attacks were graded as mild (81%) and 26 as severe (19%). Ranson (p = 0.3) and APACHE II (p = 0.049) scores appeared insufficiently predictive in the univariate analysis. Pancreatic imaging by CT scan was insufficiently predictive (p > 0.05), whereas the presence of extrapancreatic fluid collections was more indicative of outcome (p <0.05). With the univariate analysis, the four most reliable serum markers were pancreatic amylase (p <0.001), neutrophil elastase (p <0.05), albumin (p <0.002), and C-reactive protein (p <0.001). Results became homogeneous when the CT results were added; serum albumin plus extrapancreatic fluid collections (negative predictive value 92%-96% and positive predictive value 67%-100%) comprised the best indicator of severity. None of the parameters tested achieved sufficient predictability when used alone. Serum albumin plus extrapancreatic fluid collections comprise the best indicator of severity at the time of admission.

APACHE↗
PubMed1990

Knowledge-based analysis and understanding of medical images.

Knowledge-based image analysis and interpretation of radiological images is of significant interest for several reasons including a means to identify and label each part of the image for further automated diagnostic analysis. Also, there is a need to develop a knowledge-based biomedical image analysis system which can analyze and interpret the anatomical images (such as those obtained from X-ray computed tomography (CT) scanning) in order to help analysis of functional images (such as those obtained from positron emission tomography (PET) scanning) of the organ of the same patient. This paper deals with the design and implementation of a knowledge-based system to analyze and interpret CT anatomical images of the human chest. In the approach presented here, the emphasis has been on the development of a strong low-level analysis system with the capability of analyzing in both bottom-up and top-down modes; and on the use of hierarchical relational, spatial, and structural knowledge of human anatomy in the process of high-level analysis and recognition.

Artificial Intelligence↗
PubMed2000

Computed tomography in endometrial carcinoma.

OBJECTIVE: To determine the value of computed tomography (CT) scans for preoperatively detecting extrauterine-nodal disease and postoperative recurrent disease in patients with endometrial cancer. METHODS: We reviewed records of 702 women with primary endometrial carcinoma that was diagnosed between 1979 and 1993. Preoperative CT findings were compared with pathologic findings to assess nodal disease. The yield of postoperative CT was reviewed in clinically suspicious and routine settings. RESULTS: Among 492 women eligible for analysis, 178 (36%) had a total 326 CT scans. Among 56 women who had preoperative CT scans and lymph node samplings, positive and negative predictive values for nodal involvement were 50% and 94%, respectively, and sensitivity and specificity were 57% and 92%, respectively. Preoperative CT findings altered treatment plans in only six patients (8%). Forty-five asymptomatic women had 73 routine CT scans, and recurrence was diagnosed by CT in only two (4.4%). Thirty-seven women had CT scans for suspicion of recurrence, which was confirmed in 17 (46%). Kaplan-Meyer analysis showed no survival advantage in women with subclinical recurrences diagnosed by CT scan. CONCLUSION: Routine preoperative CT scanning rarely alters treatment and is a poor predictor of nodal disease. Computed tomography in the postoperative period might be helpful for detection and follow-up of recurrent disease, but there was no difference in survival when subclinical recurrence was found by CT. Thus, CT scanning of any woman with endometrial cancer should be discouraged unless it is to evaluate symptoms.

Carcinoma↗
PubMed2005

[Contribution of computed tomography in experimental sinus surgery].

OBJECTIVES: To study the contribution of computed tomography (CT) to evaluate the intensity of the sinus mucosa's response to an inflammatory stimulus. MATERIAL AND METHODS: Eight New-Zealand white rabbits where used. Rabbit n degrees 1 was the control. CT, macroscopic examination with analysis of secretion volumes, and histological examination were used to study the response of the sinuses to inflammation. RESULTS: There was perfect match between the CT scan aspect and the quantity of secretions (kappa and Cohen's coefficient=1). The CT scan aspect well correlated with inflammatory cell infiltration (kappa and Cohen's coefficients=0.8). CONCLUSION: The CT scan contributes usefully to the analysis of sinus contents and can be used to assess the intensity of the sinus mucosal inflammatory reaction. Consequently, the CT scan can be used not only to validate an animal model of acute or chronic sinusitis, but can also be used to evaluate medical or surgical treatments in such an animal model.

Animals↗
PubMed1999

Biliary imaging by spiral CT cholangiography--a retrospective analysis.

CT cholangiography employs spiral CT scanning after the administration of biliary contrast medium to generate three-dimensional images of the biliary tract. A retrospective review of 61 patients who had undergone CT cholangiography was performed to determine the technical efficacy and the clinical utility of the technique. The results of CT cholangiography were analysed retrospectively to determine technical success rate of the imaging procedure and to correlate imaging diagnosis with results of other diagnostic procedures and with clinical follow-up. 60 of the 61 examinations produced technically satisfactory images. 21 of these examinations showed bile duct abnormalities. (12 stones, 6 duct dilatation to papillary level, 2 post-operative strictures and 1 case of sclerosing cholangitis). The remaining 39 cases showed no bile duct abnormality. In 59 of the 60 cases, subsequent investigations and follow-up supported the CT cholangiographic diagnosis. CT cholangiography is a robust technique for imaging of the biliary tract and is a valuable addition to the battery of non-invasive biliary investigations.

Adolescent↗
PubMed2006

Morphological segmentation and partial volume analysis for volumetry of solid pulmonary lesions in thoracic CT scans.

Volumetric growth assessment of pulmonary lesions is crucial to both lung cancer screening and oncological therapy monitoring. While several methods for small pulmonary nodules have previously been presented, the segmentation of larger tumors that appear frequently in oncological patients and are more likely to be complexly interconnected with lung morphology has not yet received much attention. We present a fast, automated segmentation method that is based on morphological processing and is suitable for both small and large lesions. In addition, the proposed approach addresses clinical challenges to volume assessment such as variations in imaging protocol or inspiration state by introducing a method of segmentation-based partial volume analysis (SPVA) that follows on the segmentation procedure. Accuracy and reproducibility studies were performed to evaluate the new algorithms. In vivo interobserver and interscan studies on low-dose data from eight clinical metastasis patients revealed that clinically significant volume change can be detected reliably and with negligible computation time by the presented methods. In addition, phantom studies were conducted. Based on the segmentation performed with the proposed method, the performance of the SPVA volumetry method was compared with the conventional technique on a phantom that was scanned with different dosages and reconstructed with varying parameters. Both systematic and absolute errors were shown to be reduced substantially by the SPVA method. The method was especially successful in accounting for slice thickness and reconstruction kernel variations, where the median error was more than halved in comparison to the conventional approach.

Algorithms↗
PubMed1997

Radical radiotherapy for medically inoperable non-small cell lung cancer in clinical stage I: a retrospective analysis of 149 patients.

PURPOSE: In order to obtain the standard treatment results of medically inoperable non-small cell lung cancer (NSCLC) in Stage I in the post-CT scan era, a retrospective analysis of patients who were treated by radical radiotherapy was performed. METHODS AND MATERIALS: 149 cases treated between 1980 and 1989 were accumulated from ten large hospitals in Japan. All patients received a total dose of 55-75 Gy (mean 64.7 Gy) with conventional fractionation. For evaluation of treatment results, complete response (CR) rate, median survival period and long-termed survival rates were used. RESULTS: The median survival of the all cases was 27.2 months and the actuarial 3- and 5-year survival rates were 34.2% and 22.2%, respectively. CR was obtained in 57 cases (38%). The CR rate was strongly correlated with the long-term survival (5-year survival rate in CR group: 35.1% compared with PR + NC group: 14.1% (P < 0.0001)). The size of tumor was also of prognostic importance. In 116 patients who died within 5 years after treatment, 66 patients (57%) died of local tumor regrowth. CONCLUSION: Although the medically inoperable NSCLC patients in Stage I should be offered curative radiation therapy, development of some new steps to increase the CR rate and local control rate is urgently needed.

Aged↗
PubMed2002

Computed tomography screening for lung cancer in asbestos-exposed workers.

We conducted a computed tomography (CT) screening for lung cancer in a high-risk population. Six hundred and two workers (38-81 years, 97% smokers) with asbestos-related occupational disease were screened using spiral CT and chest radiography. The national cancer registry was checked for possible false negative cases. The screening detected 111 patients with non-calcified nodules >0.5 cm in diameter and 66 of them were referred for further hospital examination. We found five lung cancers (106 false positive cases) with a histological spectrum similar to the national, natural occurrence of the disease (two adeno, one squamous cell, one anaplastic and one metastatic carcinoma) and one peritoneal mesothelioma. Three cases were potentially operable (stage I-II). Unfortunately there was one false negative fine-needle aspiration biopsy (FNAB) with misinterpretation of the follow-up CT scan and another patient who refused further investigations after an inadequate FNAB. In the end only one patient with adenocarcinoma underwent surgery. After 3 years of follow-up two new lung cancers were reported to the cancer registry with no evidence of tumour in the retrospective analysis of the screening CT scan. The sensitivity of CT screening was 100%. CT was capable of detecting early lung cancer in asbestos-exposed patients with a lot of confusing pulmonary and pleural pathology. Due to the high number of positive findings attention should be paid to patient compliance and the follow-up protocols and patient selection in future screening programmes.

Adenocarcinoma↗
PubMed1989

[Utilization of findings from computerized tomography of the brain in psychiatric diagnosis].

The application and critical evaluation of brain-computed tomography (CT) to psychiatry are presented primarily in relation to the cerebral atrophies and organic brain syndromes. It can be observed, that clinical diagnosis of brain atrophy is frequently made only upon findings of diffuse cortical atrophy. The attention is directed to the non-consistent CT scan measures and diagnostic criteria of brain atrophy on CT scan due to non-consistent methodologies of sulcus and ventricular measurements. The linear and planimetric measurements and difficulties in exact analysis of cerebral atrophy on CT scanning are discussed. The nosology, clinical criteria and etiology of chronic organic brain syndromes, the clinical conditions and diseases connected with diffuse cerebral atrophy noticeable on CT scan are reported. The conclusion is, that diffuse cerebral atrophy on CT scan without clinical symptoms and criteria of cerebral atrophy cannot be considered as basis for making psychiatric diagnosis, respectively, that such finding needs other exact clinical, psychiatric and psychological examinations.

Atrophy↗
PubMed1996

Measurement of the total body fat content of growing rabbits by X-ray computerised tomography and direct chemical analysis.

The total body fat content of growing rabbits was determined by X-ray computerised tomography (CT) and direct chemical analysis. Serial scans were taken on Pannon White rabbits at the age of 6, 8, 10, 12, 14 and 16 weeks (10 animals per group). A total of seven scans per animal were evaluated, two from the scapular arch, three from the region of the kidney, and two from the pelvic region. The variables of the prediction equations were derived from the X-ray density values of the Houndsfield scale interval between -140 and -50, by adding up the frequencies within intervals of 10. Different models were developed on the basis of the MGLH stepwise procedure and Principal Component analysis. The R2 values of the estimations varied between 0.76 and 0.90. The costs of the CT procedure were reduced by scanning three animals at a time.

Adipose Tissue↗
PubMedDate not supplied

Characteristics and outcome of acute stroke patients not investigated with computerised tomography scan.

BACKGROUND: It is desirable that all acute stroke patients are investigated with a computerised tomography (CT) scan, but there may be situations when this is not possible. OBJECTIVE: To investigate the characteristics and outcome of acute stroke patients not investigated with a CT scan and whether 'not performing a CT scan' influences mortality. METHODS: Consecutive acute stroke patients admitted to a general hospital were studied for baseline characteristics, previous stroke, pre-stroke Rankin score, post-stroke neurological details, functional disability, complications and acute phase and 3-month mortality. Patients were categorised into two groups depending on whether or not they were investigated with a CT scan. chi(2) and regression analysis were performed to study characteristics and mortality. RESULTS: Ninety-four of the 296 patients did not undergo investigation with a CT scan. These patients were older (p = 0.001), had suffered previous strokes and had a poorer general health prior to admission (p < 0.001). Although there was no difference in clinical stroke syndromes and immediate post-stroke functional impairment, they had a greater impairment of level of consciousness (p = 0.003) and had a higher acute phase and 3-month mortality (p = 0.001). Not being investigated with a CT scan had an adverse influence on 3-month mortality independent of other variables. CONCLUSION: Whilst not investigating with a CT scan in acute stroke patients carries a poor prognosis, a group of patients may be managed without this investigation because of their poor pre-existing general health. These facts may be considered when preparing local guidelines for brain imaging for acute stroke patients.

Adult↗
PubMed1999

Analysis of time management in stroke patients in three French emergency departments: from stroke onset to computed tomography scan.

The aim of this study was to determine and identify the factors associated with shortening or lengthening time interval from stroke onset to performance of computed tomography (CT) scan in stroke patients admitted to three French emergency departments. All suspected stroke patients were eligible (n = 317). The time intervals between stroke onset and presentation to the emergency department and between CT scan request and CT scan performance were determined. Twelve variables likely to influence time interval before presentation to the emergency department, and five variables likely to influence time interval before CT scan performance were evaluated using stepwise regression analysis. Of the 317 patients included in the study, the mean time interval from stroke onset to CT scan performance for 180 patients was 7 hours 46 minutes (466 minutes). The mean time interval between stroke onset and presentation to the emergency department was 4 hours 36 minutes (276 minutes), varying according to the study site, level of initial severity, medical contact before admission, witnesses at stroke onset, and mode of transportation. The mean time interval between request and CT scan performance was 2 hours 14 minutes (134 minutes), varying upon the site, hour of CT scan request, type of stroke and level of severity at admission. It is concluded that current delays in stroke management are often incompatible with early treatment. The public needs to be informed and admission procedures reorganized. Improved response to the urgency of ischaemic stroke is required as well as direct access to the scanner during periods of scheduled use.

Aged↗
PubMed2001

Can we predict poor outcome at presentation in patients with lobar hemorrhage?

OBJECTIVE: Supratentorial lobar hemorrhage can be devastating. Outcome prediction at presentation is important in triage and management decisions as well as appropriate resource utilization. We performed a decision tree analysis combining clinical and CT scan features to predict poor and hopeless outcome at initial presentation in patients with lobar hemorrhage. METHODS: We analyzed 81 patients with spontaneous lobar hemorrhage presenting within 48 hours of initial neurologic symptoms. In the first analysis, poor outcome was defined as Glasgow outcome score (GOS) of 1 (death), 2 (vegetative state) or 3 (dependence) at discharge. A second analysis was based on worst possible outcome (GOS 1-2). Binary recursive partitioning was fitted in a model, and odds ratios with 95% confidence intervals (CI) were calculated. RESULTS: Lobes involved were temporal (36%), parietal (33%), frontal (25%) and occipital (6%). Seventy-three percent of patients presented less than 17 h after initial ictus. The probability of poor outcome was 97% (CI 85-100%) in patients with hemorrhage greater than 40 cm(3). In the subset of patients with a volume less than 40 cm(3), time interval from ictus to presentation (< 17 h) together with a Glasgow coma score (GCS) less than or equal to 13 predicted poor outcome. Eighty-five percent (CI 42-99%) of those presenting early with GCS less than or equal to 13 had a poor outcome. In the second analysis, all patients with GCS less than or equal to 12 and septum pellucidum shift > 6 mm had GOS of 1 or 2 (CI 72-100%). CONCLUSION: Poor outcome in patients with lobar hemorrhage is associated with a hemorrhage size of more than 40 cm(3), GCS less than or equal to 13, but also dependent on time interval between ictus and presentation. This is consistent with prior studies demonstrating deterioration from enlargement may occur when patients present early on. Stupor and septum pellucidum shift greater than 6 mm on CT scan at presentation predict a hopeless outcome in conservatively treated patients. Ninety-one percent of patients were treated medically, thus these outcomes are largely a reflection of the natural history of spontaneous lobar hemorrhage. These signs may influence triage and management decisions.

Adolescent↗