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PubMedDate not supplied

Cost-benefit analysis in screening. Unexplained visual loss.

Cost-effectiveness analysis (CEA) and cost-benefit analysis (CBA) are accounting techniques that have been applied to medical decision-making. These techniques are applied here to two alternative diagnostic strategies in the work-up of patients with "unexplained visual loss." The first uses the results of visual field examination to decide if patients should have a CT scan ("visual field strategy"), the second bypasses visual fields and orders a CT scan on all patients ("CT strategy"). The analysis reveals that the visual field strategy is cost-effective only if perimetrists are able to identify hemianopic field defects in more than 80% of cases. It is doubtful that perimetrists are presently as accurate as that. These conclusions must be considered tentative since the epidemiologic data that support them are often weak. Another drawback in applying such an analysis to medical problem-solving is that costs may not accurately reflect patient valuations and choices. Nevertheless, in forcing a more comprehensive consideration of the effects of medical decisions, CEA/CBA is likely to promote increased cost-consciousness and epidemiologic research.

Cost-Benefit Analysis↗
PubMed2001

Failed medialization laryngoplasty: management by revision surgery.

OBJECTIVE: The purpose of this study was to evaluate the cause of immediate and late medialization laryngoplasty failures and to describe their management. METHODS: A retrospective analysis was performed in 20 patients who underwent revision surgery after failed medialization laryngoplasty. Analysis was based on preoperative spiral CT scan, preoperative and postoperative videostrobolaryngoscopy, and phonatory function measures. RESULTS: Three major types of failures were identified. The most common problem was arytenoid rotation with a persistent posterior glottic gap (11 of 20). Malposition or wrong size of the implants resulted in a lateralized vocal fold or false vocal fold medialization (6 of 20). Three patients had implants that were extruding. Late atrophy and bowing resulted in a glottal gap (2 of 20). One patient had fibrosis around the implant requiring removal. Spiral CT scan of the larynx located the implant precisely and showed the degree of arytenoid rotation. Patients with arytenoid rotation and posterior gap had revision medialization combined with arytenoid adduction. Revision medialization was performed in 11 patients, arytenoid adduction in 12 patients, lipoinjection in 2 patients, and 4 implants were removed. The voice was improved in 15 patients. Improved voice was correlated with improved phonation time and reduced phonatory airflow rates. CONCLUSION: Immediate and late failures of medialization laryngoplasty are due to several possible causes. Revision surgery is feasible and highly successful. To select between the surgical alternatives work up should include preoperative analysis of vocal function, videostrobolaryngoscopic analysis, and spiral CT of the larynx.

Adult↗
PubMed2001

Automated detection of lung nodules in CT scans: preliminary results.

We have developed a fully automated computerized method for the detection of lung nodules in helical computed tomography (CT) scans of the thorax. This method is based on two-dimensional and three-dimensional analyses of the image data acquired during diagnostic CT scans. Lung segmentation proceeds on a section-by-section basis to construct a segmented lung volume within which further analysis is performed. Multiple gray-level thresholds are applied to the segmented lung volume to create a series of thresholded lung volumes. An 18-point connectivity scheme is used to identify contiguous three-dimensional structures within each thresholded lung volume, and those structures that satisfy a volume criterion are selected as initial lung nodule candidates. Morphological and gray-level features are computed for each nodule candidate. After a rule-based approach is applied to greatly reduce the number of nodule candidates that corresponds to nonnodules, the features of remaining candidates are merged through linear discriminant analysis. The automated method was applied to a database of 43 diagnostic thoracic CT scans. Receiver operating characteristic (ROC) analysis was used to evaluate the ability of the classifier to differentiate nodule candidates that correspond to actual nodules from false-positive candidates. The area under the ROC curve for this categorization task attained a value of 0.90 during leave-one-out-by-case evaluation. The automated method yielded an overall nodule detection sensitivity of 70% with an average of 1.5 false-positive detections per section when applied to the complete 43-case database. A corresponding nodule detection sensitivity of 89% with an average of 1.3 false-positive detections per section was achieved with a subset of 20 cases that contained only one or two nodules per case.

Adult↗
PubMed2005

Transthoracic endosonography for the intraoperative localization of lung nodules.

BACKGROUND: Transthoracic ultrasonography has been advocated for the localization of lung nodules during video-assisted thoracoscopic surgery (VATS) for nonperipheral nodules. METHODS: Video-assisted thoracoscopic surgery for lung nodules was performed in 54 consecutive patients. Preoperative computed tomography (CT) diagnosed 65 lesions. Positron emission tomography (PET) identified 2 lesions not revealed by CT. All nodules were judged whether visible and/or palpable. Diameter and distance of the nodule from the anterior, lateral, and posterior chest wall were measured on CT scan and served in a discriminant analysis to predict which nodule would be neither visible nor palpable. The deflectable multifrequency (7.5 to 10 MHz) endosonography probe was used to identify the nonvisible and nonpalpable nodules. RESULTS: Resected nodules were 69; 67 diagnosed preoperatively, and 2 intraoperatively by ultrasonography. At VATS exploration 16 of 65 (25%) of the CT diagnosed nodules were nonvisible and nonpalpable. The discriminant analysis failed to predict correctly whether nodules would be visible and/or palpable in 33% because of surrounding severe emphysema, proximity to a fissure, or to the hylum. The endosonography identified 15 out of 16 of the nonvisible and nonpalpable nodules, thus conversion to thoracotomy was necessary for one nodule. The combination of video, palpatory, and endosonographic inspections had 98% sensitivity and 100% specificity in localizing the nodules. CONCLUSIONS: Intraoperative transthoracic ultrasonography is useful to guide VATS resection of lung nodules. It is a bedside tool, not requiring planning and coordination with the interventional radiology suite, thus you use it if you need it. It has no related morbidity, and may also have a role in revealing lesions occult at preoperative work-up.

Carcinoma, Non-Small-Cell Lung↗
PubMed1988

Computerized tomographic prediction of extraluminal spread and prognostic implications of lesion width in esophageal carcinoma.

The use of preoperative computed tomographic (CT) scans of the chest in carcinoma of the esophagus to associate preoperative staging with postoperative survival is controversial. Thirty-two patients who underwent esophagectomy and reconstruction were examined with respect to a variety of variables available on preoperative evaluation, including lesion width on CT scan, lesion length on CT scan, and barium esophagogram. Each variable was evaluated for its ability to predict the presence of extraesophageal spread of tumor, as determined pathologically by logistic regression analysis. Lesions greater than 3.0 cm in width by CT scan were associated with a significantly higher incidence of extraesophageal spread. Tumor location, gender, histologic grade, presence of in situ lesions, vascular invasion, eosinophilia, nodal metastases, and preoperative chemotherapy had no predictive value for survival. Duration of survival was affected by the presence of esophageal spread of disease and lesion width. These results indicate that preoperative CT scanning can predict extraesophageal spread of tumor, and this is associated with overall survival.

Actuarial Analysis↗
PubMed2006

Colorectal carcinoma, preoperative evaluation by spiral computed tomography.

OBJECTIVES: To assess the capability of spiral computed tomography (CT) scan in preoperative evaluation of colorectal carcinoma (CRC). METHODS: A cross sectional study on 52 patients with recent histopathologic diagnosis of CRC was conducted over a period of one year at the Aga Khan University Hospital, Karachi. All these patients underwent spiral CT with oral and intravenous contrast administration. Surgery was subsequently done in all cases and surgical specimens were sent for detailed pathologic analysis. The radiologic findings on the CT scans were compared with the pathological findings. RESULTS: The results proved that spiral CT had 60% sensitivity and 83% specificity for assessment of local spread of disease, 66% sensitivity and 76% specificity for the evaluation of lymph nodal metastases and 89% sensitivity and 94% specificity for hepatic metastases. In all the cases, the visualized tumour growth with wide zone of resection and regional nodal chains were surgically removed. It was however, the distant metastases which made a difference to the type of curative or palliative surgery planned and in this study spiral CT had 92% accuracy for detection of hepatic metastases. CONCLUSION: With technological advances and improvement in imaging protocols the results for local tumor spread are expected to improve, however based on the accuracy in detecting hepatic metastases in clinically unsuspected patients, this study proves that spiral CT has a significant role in preoperative evaluation and subsequent management of CRC.

Adult↗
PubMed2001

A population-based study on brain atrophy and motor performance in elderly women.

BACKGROUND: Brain atrophy is a common neuroimaging finding in healthy elderly individuals as well as in patients with movement-related disorders. The relationship between brain atrophy and motor changes has not been frequently reported. This study investigates this relationship. METHODS: A population-based sample of women (N = 238), aged 70, 74, and 78 years, living in Göteborg, Sweden, participated in this study. Motor performance was measured by a laboratory test, the Postural-Locomotion-Manual test, which precisely measures the subject's mobility of lower and upper extremities using an optoelectronic technique. Cortical and central atrophy were rated on computerized tomographic (CT) scans of the brain. RESULTS: In bivariate analysis, temporal lobe atrophy, high sylvian fissure ratio, and high bicaudate ratio were correlated with impaired mobility. The association between temporal lobe atrophy and high sylvian fissure ratio and poor mobility remained after controlling for age, smoking, coronary heart disease, diabetes mellitus, hypertension, and white matter lesions on CT scans. CONCLUSIONS: Our results suggest that temporal lobe atrophy, which is often seen on brain imaging in elderly persons, might be an important brain abnormality related to motor impairments in elderly women. Further studies to investigate this relationship and its underlying mechanisms are needed.

Age Distribution↗
PubMed2005

Computer-assisted image analysis of bronchioloalveolar carcinoma.

In clinical trials, response rate is an important endpoint for assessing the efficacy of an anticancer drug. The Response Evaluation Criteria for Solid Tumors (RECIST) has been widely used as a standard method to assess response. The RECIST requires only 1-dimensional measurement of tumor size. However, bronchioloalveolar carcinoma (BAC), which commonly presents as infiltrative or micronodular lesions, is not always readily assessable by RECIST. During the past 2 years, we have been developing computer-based programs to more accurately measure tumor size on chest computed tomography (CT) scans. In a first-generation computer-assisted image analysis (CAIA) system, we were able to capture and quantify lesions on CT scans by linking the software programs of eFilm, HyperSnap, and Scion. We have applied this CAIA approach to measuring BAC response to gefitinib in the Southwest Oncology Group (S0126) trial. However, this first-generation CAIA system involves multiple manual steps and is therefore labor intensive. We are now developing a fully automated CAIA program based on a versatile software platform, ImageJ, created at the National Institutes of Health. Taking theoretical and physical considerations into account, Java plug-in programs for ImageJ are created to automatically analyze CT scans in the Digital Imaging and Communications in Medicine format. We have demonstrated the feasibility of an ImageJ-based automated CAIA program for measuring BAC bidimensionally on CT scans. This automated CAIA system will be applied in a prospective clinical trial of the GVAX vaccine in patients with BAC.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed1997

A CT scan technique for quantitative volumetric assessment of the mandible after distraction osteogenesis.

Distraction osteogenesis has become an accepted method of treatment for patients requiring reconstruction of hypoplastic mandibles. We present a quantitative analysis of volumetric changes after distraction osteogenesis in a series of 10 patients. Group I (n = 5 patients, 3 unilateral craniofacial microsomia, 1 Goldenhaar syndrome, and 1 bilateral craniofacial microsomia) underwent unilateral distraction of the mandible. Group II (n = 5 patients, 1 Nager syndrome, 1 bilateral craniofacial microsomia, 1 developmental micrognathia, and 2 Treacher Collins syndrome) underwent bilateral distraction of the mandible. Predistraction and postdistraction axial and three-dimensional computed tomographic (CT) scans were digitized and transferred to a computer for analysis with image-processing software to determine the changes in volume of the mandible and bony regenerate. The CT-derived volume method was validated by scanning three dry cadaver mandible specimens and comparing the volume data with those derived from a water-displacement method. The difference between the two methods was less than 5 percent. The mean distracted length, as recorded from the calibrated device, was 22.6 mm in the 10 patients. In the unilateral distraction group, the mean increase in hemimandibular bone volume was 2.8 cc, with a mean percentage increase of 27 percent in the distracted hemimandible. In the bilaterally distracted patients, the mean increase in total mandibular volume was 7.9 cc, with a mean percentage increase in bone volume of 25 percent. This study represents the first attempt to quantify the increase in bone volume resulting from distraction osteogenesis. Quantitative volumetric analysis of CT scans is an accurate method to measure the amount of bone regenerate in patients undergoing distraction osteogenesis of the mandible or the extremities. The concept and utility of quantifying the volumetric changes in bone following distraction osteogenesis may become more important as multiplanar devices are developed and used in other areas of the craniofacial skeleton.

Adolescent↗
PubMedDate not supplied

Comparison of 18FDG-PET with CT scans in the evaluation of patients with residual and recurrent Hodgkin's lymphoma.

The reliable assessment of residual masses after treatment as well as of new lesions suspected for relapse remains a diagnostic problem in patients with Hodgkin's disease (HD). The current study compares the results obtained by CT scan to FDG-PET imaging in a blind analysis with respect to the viability of residual masses and in case of suspected relapse. Between 1/94 and 10/99, 47 comparisons of PET and corresponding CT scans - 26 comparisons in 24 patients with residual tumors and 21 comparisons in 20 patients with suspected relapse of HD - were evaluated by independent reviewers blinded to he results of each other. Patients with primary diagnosis had been treated within trials of the German HD Trial study group. Relapsed patients received intensified salvage chemotherapy regimens. PET was assessed visually and by quantifying glucose uptake (SUV). Changes in size of tumor lesions as well as contrast medium enhancement served as criteria for assessment by CT scans. Results were validated either by histologic examination of a resected mass or biopsy (n=17) or by a clinical follow-up over 6 months following treatment (n=30). In 26 cases with residual lesions FDG-PET showed an increased tracer uptake in 8, 7 of which were true positive (TP) and 1 false positive (FP). Eighteen cases were classified as being negative (no viable HD), 17 true negative (TN) and 1 FN. In the blinded reading of the corresponding CT scans, 10 cases with residual lesions were considered to contain vital lymphoma (2 TP, 8 FP). Sixteen CT scans were classified as negative (10 TP, 6 FN). The resulting sensitivity and specificity of PET were 87.5% and 94.4% in contrast to only 25% and 56% for CT scans. The positive and negative predictive values of PET and CT scans were 87.5% and 94.4% and 20% and 62.5%, respectively. In patients with suspected relapse, sensitivity and positive predictive value for the diagnosis of the relapse were 100% and 86%, respectively, yielding the same results for both methods. FDG-PET performed in HD patients with residual masses appears to offer important additional information regarding the presence of viable HD in these residual lesions. In patients with suspected relapse of HD, FDG-PET seems not to offer any information over CT scans. Using SUVs is not superior to visual assessment of PET alone.

Adult↗
PubMed1998

[Intraoperative ultrasound study of thoracolumbar spinal fractures with spinal canal fragments. Determining canal width and anatomic control of decompression: comparative analysis with CT].

Intraoperative ultrasonography is recommended for operations on the thoracolumbar spine to complement the information provided by standard X-ray, intensifier screen or myelography. There are no unanimates opinions concerning the impaction or exeresis of these fragments. The aim of this study was to show the advantages of intraoperative ultrasonography for anatomic determination and control of the maneuvers used. This study included 46 cases with fractures from T11 to L2. Ultrasonography was performed during the intraoperative reduction provided by the installation and the pedicular instruments. The authors stress the limits of the anatomic and geographic determination, as well as tilting of the fragments because of the size of the ultrasonographic head. The quality of the exeresis may be falsely interpreted in the presence of fragments with a section of less than 4 mm, lateralized, double fragments or in the presence of massive intraoperative haemorrhage. Analysis of the impaction results is more complicated because all of these fragments displaced themselves secondarily. The ligamentum communis vertebralis posterior has no anatomical containing role. The tilting before the impaction and the state of the overlying intervertebral disk represent essential factors for failures. Ultrasonography is better than intraoperative myelography. Nevertheless, it still needs to be complemented by intraoperative profile X-rays and a very precise preoperative CT scan of the intervertebral disk lesions analysis of complicated cases (fragments with residual pedicular attachments--type A 3.1.2.; T-like fractures--type A 3.2.1.).

Adult↗
PubMedDate not supplied

Threshold analysis using diagnostic tests with multiple results.

Clinical problems represented by decision trees can be analyzed in terms of the probability threshold model, which provides management recommendations based on the prior probability of disease, the test threshold, and the test-treatment threshold. As originally proposed, the threshold model assumes that diagnostic tests provide information about a single event that is relevant to the decision. For some problems, however, a diagnostic test may provide information about more than one such event (e.g., a computed tomography [CT] scan gives information about both mediastinal and hilar metastases in lung cancer). The authors extend the probability threshold model to cases in which a single test provides information about two events that are relevant to the decision. They derive four thresholds that determine the best strategy for any combination of test results. The approach is illustrated for the decision to use a CT scan to stage lung cancer. The analysis reveals that: 1) the range of prior probabilities for which testing is optimal increases; 2) for some prior probabilities only test results about one event are important; 3) for some prior probabilities test results about both events are important; and 4) failure to account fully for information provided by a test can lead to erroneous test and treatment recommendations.

Bayes Theorem↗
PubMed1996

Comparison of electron beam computed tomography scanning and magnetic resonance imaging quantification of right ventricular mass: validation with autopsy weights.

RATIONALE AND OBJECTIVES: We compared, in the same human hearts, the ability of magnetic resonance (MR) imaging and electron beam computed tomography (CT) scanning to accurately quantify the free wall and septal components of right ventricular (RV) mass. METHODS: Eleven hearts extracted at autopsy were subjected to MR imaging and electron beam CT scanning in short-axis projections. Regression analyses of mass determinations obtained by manual planimetry MR imaging and electron beam CT scanning and autopsy weights were performed. RESULTS: RV free wall mass by both MR imaging (53.4 +/- 19.1 g) and electron beam CT scanning (53.9 +/- 20.4 g) correlated well with autopsy weight (57.7 +/- 20.2 g). Regression analysis showed a strong correlation for MR imaging (r = .88, slope = .88, standard error the estimate [SEE] = 7.2 g, p < .001) and electron beam CT scanning (r = .95, slope = .95, SEE = 6.6 g, p < .001). RV septal mass by MR imaging (10.8 +/- 3.5 g) and electron beam CT scanning (7.1 +/- 2.4 g) correlated less well with the autopsy weight (12.5 +/- 6.5 g). Regression analysis showed a fair correlation for MR imaging (r = .45, slope = .83, SEE = 2.05 g, p = .001) and a poor correlation for electron beam CT scanning (r = .46, slope = .17, SEE = 2.25 g, p = .57). CONCLUSION: Both MR imaging and electron beam CT scanning accurately predict RV free wall mass but have difficulty predicting the septal component. Because the septal component constitutes only a small proportion of the total RV mass, determinations of RV mass should be based solely on the free wall component.

Autopsy↗
PubMed2003

Assessment of severity of ovine smoke inhalation injury by analysis of computed tomographic scans.

BACKGROUND: Our goal was to evaluate computed tomographic (CT) scans of the chest as a means of stratifying smoke inhalation injury (SII) severity. METHODS: Twenty anesthetized sheep underwent graded SII: group I, no smoke; group II, 5 smoke units; group III, 10 units; and group IV, 16 units. CT scans were obtained at 6, 12, and 24 hours after injury. Each quadrant of each slice was scored subjectively: 0 = normal, 1 = interstitial markings, 2 = ground-glass appearance, and 3 = consolidation. The sum of all scores was the radiologist's score (RADS) for that scan. Computerized analysis of three-dimensional reconstructed scans was also performed, based on Hounsfield unit ranges: hyperinflated, -1,000 to -900; normal, -899 to -500; poorly aerated, -499 to -100; and nonaerated, -99 to +100. The fraction of abnormal lung tissue (FALT) was computed from poorly aerated, nonaerated, and total volumes. Mean gray-scale density (DENS) was also computed. RESULTS: SII resulted in severity- and time-related changes in oxygenation (alveolar-arterial gradient), ventilation (respiratory rate-pressure product), DENS, FALT, and RADS. Ordinal logistic regression generated a predictive model for severity of injury (r2 = 0.623, p = 0.001), retaining RADS at 24 hours and rejecting the other variables. CONCLUSION: At 24 hours, CT scanning enabled SII severity stratification; qualitative evaluation (RADS) outperformed current semiautomated methods (DENS, FALT).

Animals↗
PubMed1993

Chest tumor response during lung cancer chemotherapy. Computed tomography vs fiberoptic bronchoscopy.

Tumor response is one of the most important criteria in the analysis of chemotherapy. A chest computed tomographic (CT) scan and fiberoptic bronchoscopy (FOB) might give different results, as they analyze different aspects of the effects of chemotherapy on lung cancer. The response of the chest tumor in 103 patients with stage III or IV lung cancer (35 with small-cell lung cancer [SCLC] and 68 with non-small-cell lung cancer [NSCLC]) who prospectively entered chemotherapy trials was studied in order to determine the concordance between the chest CT scan and FOB. The chest CT scan allowed an assessment of tumor response in almost all patients, whereas FOB was not able to evaluate this response in 15 of the 103. The frequency of an evaluable endobronchial lesion did not depend on histology (SCLC, 97 percent; NSCLC, 93 percent; chi 2 = 0.85; not significant [NS]) or tumor T classification (T1-2, 83 percent; T3, 94 percent; T4, 97 percent; chi 2 = 1.49; NS). Tumor location in the bronchial airway did not differ when SCLC and NSCLC were compared. Thus, it is not possible to predict a subgroup of patients in whom FOB may be optional. In the group of 88 patients who were evaluable for response using both FOB and CT scan, a statistical concordance of the response classification was observed. The response was overevaluated by CT scan in 22 patients for whom data obtained by FOB appeared to be critical in the evaluation of tumor response. The concordance of response data obtained when the 2 methods were used was lower in NSCLC in comparison with SCLC. Thus, the use of FOB in the analysis of tumor response might be important, especially for NSCLC, inasmuch as FOB modulates the CT-evaluated response.

Adult↗
PubMed2002

Role of chest computed tomography at diagnosis in the management of Wilms' tumor: a study by the United Kingdom Children's Cancer Study Group.

PURPOSE: This study sought to determine whether the identification of minimal pulmonary metastatic disease by chest computed tomography (CT) performed at diagnosis in patients with Wilms' tumor and normal chest x-rays (CXR) could predict a subgroup of children at increased risk of pulmonary relapse. PATIENTS AND METHODS: A retrospective analysis was carried out of the records of 449 children entered onto the United Kingdom Childrens' Cancer Study Group Second Wilms' Tumor Study between July 1986 and September 1991. The imaging protocol did not stipulate chest CT at diagnosis, but 141 children who had normal frontal and lateral CXRs and a chest CT scan performed at diagnosis were eligible for analysis. After surgery, children with stage I Wilms' tumor received single-agent chemotherapy (vincristine), whereas children with stages II, III, and bilateral Wilms' tumor received combination chemotherapy. Most children with stage III tumors were also treated with abdominal radiotherapy (20 Gy). RESULTS: In 31 patients (22%), pulmonary nodules were visible on chest CT; eight experienced relapse, four (15%) in the lungs. When only stage I patients were analyzed, there was a significant difference between the pulmonary relapse rate of 43% (three of seven) in the CT-positive group and 10% (five of 48) in the CT-negative group (P =.02). Four of eight patients with stage I disease with pulmonary relapse died. CONCLUSION: CT seemed to identify a subgroup of stage I patients who were at increased risk of pulmonary relapse. These children had received only single-agent chemotherapy. A prospective randomized trial is needed to clarify whether these children would benefit from combination chemotherapy.

Antineoplastic Agents, Phytogenic↗
PubMed1980

Chest computed tomography in infants and children. An analysis of 50 patients.

Chest computed tomography (CT) scans were performed in 50 pediatric patients. The techniques and inherent problems are presented. CT provides detailed anatomic information about the chest wall, mediastinum, and lungs. Pediatric chest CT is particularly valuable in the evaluation of extrapleural masses, parenchymal metastatic disease, and posterior mediastinal tumors.

Adolescent↗