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T Vehmas

Publications and source records attributed to T Vehmas.

At least 19 recordsLinked to original sources
PubMed2006

Chest CT screening of asbestos-exposed workers: lung lesions and incidental findings.

The objective of the present study is to determine the feasibility of chest computed tomography (CT) in screening for lung cancer among asbestos-exposed workers. In total, 633 workers were included in the present study and were examined with chest radiography and high-resolution CT (HRCT). A total of 180 current and ex-smokers (cessation within the previous 10 yrs) were also screened with spiral CT. Noncalcified lung nodules were considered positive findings. The incidental CT findings not related to asbestos exposure were registered and further examined when needed. Noncalcified lung nodules were detected in 86 workers. Five histologically confirmed lung cancers were found. Only one of the five cancers was also detected by plain chest radiography and three were from the group of patients with a pre-estimated lower cancer probability. Two lung cancers were stage Ia and were radically operated. In total, 277 individuals presented 343 incidental findings of which 46 required further examination. Four of these were regarded as clinically important. In conclusion, computed tomography and high-resolution computed tomography proved to be superior to plain radiography in detecting lung cancer in asbestos-exposed workers with many confounding chest findings. The numerous incidental findings are a major concern for future screenings, which should be considered for asbestos-exposed ex-smokers and current smokers.

Aged↗
PubMed2006

Aggrecan core protein of a certain length is protective against hand osteoarthritis.

OBJECTIVE: To study the contribution of aggrecan VNTR (variable number of tandem repeats) polymorphism to clinically differing manifestations of hand osteoarthritis (OA). DESIGN: Five hundred thirty Finnish females representing two academically similar occupations with completely diverse exposure to hand load were included. Radiographs of hands were analysed, the OA findings were graded and the subjects were divided into categories. Aggrecan VNTR alleles were identified by Southern hybridization. Statistical analyses were used to compare joint involvement and pathological findings with the prevalences of the alleles and genotypes. RESULTS: Subjects homozygous for the most common aggrecan VNTR allele, A27 with 27 repeats, had a significantly lower risk of hand OA, with OR 0.46 (95% CI 0.27-0.78) for OA of grade 2 or more. Our results suggest that carrying two copies of the alleles with less than 27 repeats could predispose a subject to a severe hand OA (OR 2.45, 95% CI 1.17-5.12) and carrying two copies of the alleles with more than 27 repeats also increases the risk of the disease (OR 1.73, 95% CI 1.03-2.89). CONCLUSIONS: These findings indicate that allele A27 provides protection from hand OA and that alleles shorter or longer than this may predispose subjects to the disease. Furthermore, they suggest that a certain number of tandem repeats provide for optimal functioning of the aggrecan molecule and that the contribution of genetic factors to the development of hand OA may be even more important than that of environmental factors.

Aggrecans↗
PubMed2006

Selection of reference films based on reliability assessment of a classification of high-resolution computed tomography for pneumoconioses.

OBJECTIVE: Worldwide demand has increased for the development of a computed tomography (CT) classification system that supplements the ILO classification of radiographs for pneumoconioses. The authors aimed to show preliminary reliability test results for selected referent films for the CT classification system developed through an international effort by researchers from seven countries. METHODS: Reading trials by eight physicians who have considerable experience in pneumoconioses using a total of 114 lung zones consisting of 6 lung zones of 19 CT films of dust-exposed workers were performed to assess reliability of the classification system by weighted kappa. The results were also utilized for selecting reference films. RESULTS: A good agreement was observed for both first and second reading trials for rounded opacities (weighted kappa=0.76, 0.74, first and second trial results, respectively), irregular opacities (0.60, 0.48), emphysema (0.56, 0.70) and honeycombing (0.72, 0.79). Ground glass opacities, on the other hand, showed moderate agreement (0.43, 0.38). Intra-reader agreements among eight readers were shown in the same table as the mean and standard deviation of weighted kappa statistics. The inter-reader agreement for pleural thickening was not as good as for parenchymal lesions. DISCUSSION: The CT classification development may pioneer noble and sensitive medical screening for dust-exposed workers in selected settings. This system may be applied to radiographic borderline cases of profusion 0/1 and 1/0 by the ILO classification, in a setting that assures the occupational safety and health of workers exposed to some newly developed chemical compounds.

Classification↗
PubMed2006

Factors influencing the detection of abnormalities in barium enemas performed by junior radiologists.

AIM: To study the effects of patient variability, technical examination and radiologist-related factors on the radiological diagnosis of barium enema studies. MATERIALS AND METHODS: Twenty-one residents (12 women and nine men, age 26-39 years) performed 523 double contrast barium enemas in a university hospital. Diagnoses were classified as normal (n = 203), diverticulosis (n = 224), polyps (n = 25), tumours (n = 20) and other (n = 46); five were missing diagnoses. Binary and multinomial logistic regressions were used to study the relations between the independent variables and the radiological diagnoses. RESULTS: Patients' advanced age (p < 0.001) and obesity (p = 0.041) were significant positive predictors for the detection of any abnormalities, as was good or moderate study quality (p = 0.023). However, patients' obesity was negatively associated with the detection of polyps (p = 0.037). Pathological findings were associated with higher dose-area products (p = 0.047) than normal cases. Residents' advanced age (p = 0.029) and experience (a high number of previously performed barium enemas; p = 0.009) were negative predictors for the detection of pathological findings. CONCLUSION: Patients' obesity hampers polyp detection, possibly due to decreased image quality or coexisting diverticula. The most experienced and oldest residents missed positive findings, possibly due to insufficient consultation of supervising radiologists, emphasizing the need for their optimal cooperation.

Adult↗
PubMed2006

Effect of computer-aided detection on mammographic performance: experimental study on readers with different levels of experience.

PURPOSE: To evaluate the effect of computer-aided detection (CAD) on the reader's performance. MATERIAL AND METHODS: Four screening radiologists, two novice radiologists, and two residents with no prior experience in CAD read films of 200 women without and with CAD. The films, including 16 screen-detected cancers and 35 cancers "missed" on prior screening, were divided into two rollers: A (free time schedule) and B (prompted time schedule). Reading times were noted. Individual readings without and with CAD were compared, sensitivities and specificities were calculated. RESULTS: The sensitivity of CAD was 70.6% and specificity 15.8%. In 408 cancer readings, the screeners found 10 and other readers 7 new cancers with the aid of CAD. The screeners changed their opinion four times and others six times from true positive to false negative when CAD was negative. CAD output produced 12 versus 13 new false-positive findings respectively after 2352 readings. CAD did not significantly affect the reader's sensitivities/specificities regardless of the time limit (P = not significant). The use of CAD increased mean time for roller reading from 56 to 63 min (P = 0.053). CONCLUSION: Screening radiologists benefited slightly more from CAD than other readers did, but no statistical significant difference was found in personal readings without and with CAD.

Breast Neoplasms↗
PubMed2006

Impact of the number of readers on mammography interpretation.

PURPOSE: To evaluate the impact of the number of readers on sensitivity and specificity, and compare it with conference consensus reading. MATERIAL AND METHODS: Eight readers read mammography films of 200 women (including 35 false-negative and 16 screen-detected cancers). The sensitivities and specificities of the two methods were calculated: either at least a single cancer-positive opinion within the group (summarized independent reading) or the cancer-positive opinion of the reader majority (conference consensus reading) was considered decisive. RESULTS: The mean sensitivity for summarized independent readings of different groups was 64.7% as compared to the 43.1% mean sensitivity of conference consensus readings. The mean specificities were 92.4% and 97.7%, respectively. The greatest sensitivity of 74.5% was achieved when the readings of the four best-performing readers were combined. CONCLUSION: The sensitivity of reading is maximal when any positive opinion within a pair or a group of readers is taken into consideration. Discordant double reading may best be judged as screening positive, and the value of a third opinion should be questioned.

Breast Neoplasms↗
PubMed2006

Finger osteoarthritis and differences in dental work tasks.

Mechanical load has been proposed as a risk factor for hand osteoarthritis. Dentists produce high manual forces in their work tasks. We studied whether the pattern of dental work tasks was associated with finger osteoarthritis. Radiographs of both hands of 291 middle-aged female dentists were examined for the presence of osteoarthritis. Patterns of dental work tasks during work history were empirically defined by cluster analysis. Three patterns emerged reflecting high, moderate, and mild task variation. Age, specialization, years in clinical work, various activities requiring hand use, family history of Heberden's nodes, body mass index, and smoking were accounted for in logistic regression analyses. The dentists with a history of low task variation had a greater prevalence of osteoarthritis in the thumb, index, and middle fingers compared with dentists with high variation (OR 2.22; 95%CI 1.04-4.91). The pattern of dental work task history is associated with the localization of osteoarthritis in the fingers.

Cluster Analysis↗
PubMed2005

Hand use and patterns of joint involvement in osteoarthritis. A comparison of female dentists and teachers.

OBJECTIVES: To investigate the effect of mechanical stress on finger osteoarthritis (OA) by comparing women from two occupations with different hand load but the same socio-economic grade, and to investigate whether hand load may affect the pattern of joint involvement in OA. METHODS: Radiographs of both hands of 295 dentists and 248 teachers were examined. Each interphalangeal (distal, proximal and thumb interphalangeal) and the metacarpophalangeal joints were graded (0 = no OA, 4 = severe OA) separately by using reference images. The co-involvement of different hand joints was analysed by logistic regression. RESULTS: The distal interphalangeal joints were the most frequently involved joints. The non-dominant hand was more frequently affected by OA of grade 2 or more than the dominant hand. The prevalence of OA of grade 2 or more in any finger joint and also in any distal interphalangeal joint was higher among the teachers compared with the dentists (59 vs 48%, P = 0.020 and 58 vs 47%, P < 0.010 respectively). Finger OA showed more clustering in the ring and little fingers and more row clustering and symmetry in the teachers than in the dentists [age-adjusted odds ratio (OR) = 1.57, 95% confidence interval (CI) 1.10-2.23, OR = 1.84, 95% CI 1.28-2.64, and OR = 1.98, 95% CI 1.38-2.86 respectively]. The OR of more severe OA (grade 3 or more) in the right-hand thumb and the index and middle fingers was significantly elevated among the dentists compared with the teachers (OR 2.61, 95% CI 1.03-6.59). CONCLUSION: Our findings indicate that finger OA in middle-aged women is highly prevalent and often polyarticular. Hand use may have a protective effect on finger joint OA, whereas continuing joint overload may lead to joint impairment.

Dentists↗
PubMed2004

Scoring CT/HRCT findings among asbestos-exposed workers: effects of patient's age, body mass index and common laboratory test results.

We studied the effects of age, body mass index (BMI) and some common laboratory test results on several pulmonary CT/HRCT signs. Five hundred twenty-eight construction workers (age 38-80, mean 63 years) were imaged with spiral and high resolution CT. Images were scored by three radiologists for solitary pulmonary nodules, signs indicative of fibrosis and emphysema, ground glass opacities, bronchial wall thickness and bronchiectasis. Multivariate statistical analyses were adjusted for smoking and asbestos exposure. Increasing age, blood haemoglobin value and erythrocyte sedimentation rate correlated positively with several HRCT signs. Increasing BMI was associated with a decrease in several signs, especially parenchymal bands, honeycombing, all kinds of emphysema and bronchiectasis. The latter finding might be due to the suboptimal image quality in obese individuals, which may cause suspicious findings to be overlooked. Background data, including patient's age and body constitution, should be considered when CT/HRCT images are interpreted.

Adult↗
PubMed2004

Revascularization decreases 8-isoprostaglandin F2alpha excretion in chronic lower limb ischemia.

8-Isoprostaglandin F2alpha is one of a series of isoprostanes formed by free radical catalysed peroxidation of arachidonic acid. Urinary 8-isoprostaglandin F2alpha is a new marker which reflects oxidative stress in vivo and can be utilized as a diagnostic tool to assess the extent of oxidative stress in various disease states associated with lipid peroxidation. Increased levels of 8-isoprostaglandin F2alpha in cardiac ischemia/reperfusion provide evidence for oxidative stress during coronary perfusion. In animal studies, the restoration of blood flow after lower limb ischemia is followed by reperfusion syndrome. In this study we investigated whether lower limb ischemia/reperfusion is associated with oxidative stress, as reflected by urinary levels of 8-isoprostaglandin F2alpha. Ten patients (mean age 72 years, range 61-82 years) suffering from chronic lower limb ischemia and 10 healthy volunteers (mean age 69 years, range 60-79 years) participated in the study. In all patients, diagnostic angiography had revealed stenosis or occlusion either in the aortoiliac or femoropopliteal region. Surgical revascularization consisted of femoropopliteal reconstruction, femorofemoral reconstruction, aortobifemorial reconstruction, or femoral endartectomy. Urine samples from patients were collected a day before surgery and in the second postoperative day. Urinary 8-isoprostaglandin F2alpha was extracted on a C2 silica cartridge and determinated by radioimmunoassay. After revascularization, 8-isoprostaglandin F2alpha excretion (pg/micromol creatinine, mean +/- SD) was decreased by 2.5-fold (preoperative 48.9 +/- 8.9, postoperative 19.1 +/- 9.5, P < 0.001). The postoperative values were similar to the concentrations measured in healthy volunteers (18.0 +/- 11.0). All revascularizations were successful, and the increase in ankle-brachial index (preoperative 0-0.6, postoperative 0.4-0.8) revealed improved blood flow in the ischemic lower limb. We suggest that, as assessed by the quantitation of urinary 8-isoprostaglandin F2alpha, chronic lower limb ischemia is associated with increased oxidative stress, which is decreased by revascularization.

Aged↗
PubMed2004

Role of radiology in occupational medicine.

This review discusses the contribution of radiology to occupational medicine as well as work-related problems in radiology departments. Research issues are emphasized. Radiology has been used especially when diagnosing occupational respiratory and locomotive system problems and solvent-induced encephalo- and hepatopathy. The aim of research in these areas is usually to characterize occupational diseases and to identify physico-chemical hazards in the work place by comparing between groups of workers and non-exposed controls. Radiological imaging allows an objective characterization of the disease, and it may clarify the pathogenesis of the process and provide a useful epidemiological tool. Advanced statistical methods are often needed to adjust analyses for confounding variables. As the diagnostic requirements are increasing, more sensitive and sophisticated radiological methods, such as high-resolution computed tomography, magnetic resonance imaging and magnetic resonance spectroscopy, may be required for the early recognition of occupational health risks. This necessitates good cooperation between occupational health units and well-equipped imaging departments. Considering occupational problems in radiology departments, the increasing use of digital radiology requires ergonomic measures to control and prevent locomotive problems caused by work with computers. Radiation protection measures are still worth concern, especially in interventional radiology.

Cumulative Trauma Disorders↗
PubMed2003

Effects of tobacco smoking on findings in chest computed tomography among asbestos-exposed workers.

This study examined the effects of smoking on the findings in chest computed tomography (CT) in 587 asbestos-exposed construction workers (11 females, 576 males, mean age 62 yrs; 18 never-smokers, 406 exsmokers and 163 current smokers). The workers were imaged with spiral CT and high-resolution CT. A total of 13 radiological signs were scored by three radiologists independently. The workers' medical data, smoking habits and occupational exposures were collected at an interview. The effects of smoking status and smoked pack-yrs (0-87.5) on the CT signs were studied using multivariate analysis adjusted for confounding factors. Smoking increased all emphysema signs and contributed to bronchial wall thickening. Smoking was negatively associated with curvilinear and septal lines as well as with parenchymal bands. In persons who had smoked <10 pack-yrs, smoking was positively related to paraseptal emphysema and to bronchial wall thickening and negatively related to septal lines, subpleural nodules and honeycombing. Smoking was related to several abnormal computed tomography signs even among those with relatively small exposure. Computed tomography can detect changes due to smoking at an early stage.

Aged↗
PubMed2003

Do radiologists' radiation-related opinions predict their fluoroscopy doses?

The influence of radiologists' radiation-related opinions to fluoroscopy doses was studied. Dose-area products (DAP), screening times and the number of exposures per patient were recorded in 528 barium enema examinations performed by 23 residents (14 female, 9 male). The residents' scored opinions (on the general radiation risk in radiology, the importance of radiation protection in radiology and their estimate of their own dose level on which they operate when compared with their colleagues) were correlated with these radiation variables. Residents' opinion on the importance of radiation protection correlated positively with screening time (r=0.402, p=0.008) and with DAP (r=0.333, p=0.028). The female residents (score 8.3) considered radiation protection more important than the males (score 7.4, p=0.029). The stability of these opinions was suggested by finding them not to correlate with residents' age or radiological experience. Residents could not reliably estimate their true dose levels, which were compared with the estimated dose levels. Fluoroscopy behaviour and doses seem to be affected by psychological factors. Further psychologically oriented studies might assist in revealing such factors and in developing proper teaching methods for radiologists to control their doses.

Attitude of Health Personnel↗
PubMed2002

Computed tomography of asbestos-related pleural abnormalities.

OBJECTIVES: To study the observer agreement in several asbestos-related pleural abnormalities and to define criteria to discriminate between pleural changes in workers with occupational disease, and those in controls. METHODS: Pleural abnormalities in spiral computed tomography of 602 construction workers with asbestosis or bilateral pleural plaques and 49 controls were reviewed by three radiologists using structured forms. RESULTS: Intra- and inter-observer agreement (weighted kappa) was 0.4 or better with regard to the calcification, extent and thickness of pleural disease. These factors all correlated positively with the duration of asbestos exposure. There were significant differences in these pleural changes between the workers (mean extent per side 83 cm(2)) and controls (mean extent per side 40 cm(2)). Of the controls, 84% showed pleural lesions with an estimated extent of 10 cm(2) or more, bilateral in 64%. The extent of 45 cm(2) in pleural disease was the best value for discriminating between the controls and diseased workers, with a sensitivity of 82% and a specificity of 66%. The degree of pleural calcification, however, was the best discriminator between these groups, but quantitative methods are necessary for its use in the diagnostics of individuals. CONCLUSIONS: The extent, calcification and thickness were well-repeatable indicators of benign pleural pathology and thus their use in future classification systems in computed tomography is recommended. In our material, the extent of 45 cm(2) and the degree of calcification were helpful in discriminating between pleural changes in workers with occupational disease, and those in controls who also presented marked pleural pathology.

Adult↗
PubMed2001

Disc height and signal intensity of the nucleus pulposus on magnetic resonance imaging as indicators of lumbar disc degeneration.

STUDY DESIGN: A cross-sectional magnetic resonance imaging (MRI) study of degeneration of the lumbar spine. OBJECTIVES: To compare the usefulness of disc height and that of T2-weighted signal intensity as indicators of disc degeneration. SUMMARY OF BACKGROUND DATA: Disc height and signal intensity have been used as indicators for disc degeneration. Their relation to each other and to early degeneration has not been well documented. There is evidence that physical load can affect disc height. METHODS: Forty-one machine operators, 41 construction carpenters, and 46 office workers, aged 40-45 years, and 22 students aged 18-20 years were examined with sagittal magnetic resonance imaging. All study participants were men. The mean value of the anterior and posterior disc height and the relative T2-weighted signal intensity of the nucleus pulposus of discs L2-L3 to L5-S1 were measured. RESULTS: Young men showed the lowest disc height but the highest relative signal intensity. Disc height showed an increasing trend from the office workers (sedentary) to blue-collar workers (more physical work) at all disc levels but L5-S1. Relative signal intensity showed a decreasing trend for these same worker types at all levels. In generalized linear modeling, signal intensity and the occupations, in reference to the young students, showed a significant effect on disc height. CONCLUSIONS: Relative signal intensity was lower in the middle-aged men than in the young men, indicating age-related disc degeneration. Despite the general positive association between disc narrowing and decreased relative signal intensity, disc narrowing may behave unexpectedly in relation to signal intensity and age. Signal intensity may be a more sensitive measure of disc degeneration. The validity of disc height as an indicator of early degeneration seems questionable.

Adolescent↗
PubMed2001

MRI abnormalities of foot and ankle in asymptomatic, physically active individuals.

OBJECTIVE: To assess MRI changes in the ankle and foot after physical exercise. DESIGN AND PATIENTS: Nineteen non-professional marathon runners and 19 age- and sex-matched controls volunteered for the study. All had ankle and foot MR images (1.5 T) taken in three perpendicular planes (STIR, T2F and T1FS sequences) within 3 h of running a full-length marathon (42.125 km). Three radiologists independently analysed the groups on a masked basis using a predefined form. RESULTS: Severe bone marrow oedema was seen in one and slight bone marrow oedema in three marathon runners. Slight bone marrow oedema was found in three control subjects. Signal alteration within the soleus muscle, consistent with a grade 1 strain, was found in one marathon runner. Small punctate hyperintensities within the Achilles tendon were seen in 26% of the marathon runners and in 63% of controls (P = 0.016). An increased amount of fluid in the retrocalcaneal bursa was found in one control and in none of the marathon runners. Small amounts of fluid in the retrocalcaneal bursa were seen in 68% of marathon runners and in 53% of controls. Grade 1 or 2 peritendinous joint fluid was found around 22% of tendons, among both marathon runners and controls, most often involving the tendon sheath of the flexor hallucis longus muscle. An increased amount of joint fluid was noted in 34% of the joints of the marathon runners, and in 18% of the controls. CONCLUSION: MRI shows several abnormalities in the ankle and foot both after marathon races and in asymptomatic physically active individuals without any preceding extraordinary strain. Recreational sports may lead to a number of positive MRI findings without correlation with clinical findings.

Adult↗
PubMed2001

Acute paediatric ankle trauma: MRI versus plain radiography.

OBJECTIVE: To evaluate the diagnosis of acute physeal ankle fractures on plain radiographs using MRI as the gold standard. METHODS: Sixty consecutive children, 29 with a clinical diagnosis of lateral ligament injury and 31 with physeal ankle fractures, were examined using both radiographs and MRI in the acute period. The imaging data were reviewed by three "masked" radiologists. The fracture diagnosis and Slater-Harris classification of radiographs were compared with findings on MRI. RESULTS: Plain radiography produced five of 28 (18%) false negative and 12 of 92 (13%) false positive fracture diagnoses compared with MRI. Six of the 12 false positive fractures were due to a misclassification of lateral ligament disruption as SH1 fractures, Altogether a difference was found in 21% of cases in either the diagnosis or the classification of the fractures according to Salter-Harris. All bone bruises in the distal tibia and fibula and 64% of bone bruises in the talus were seen in association with lateral ligament injuries. Talar bone bruises in association with fractures occurred on the same side as the malleolar fracture; talar bone bruises in association with lateral ligament disruption were seen in different locations. The errors identified on radiographs by MRI did not affect the management of the injury. CONCLUSIONS: The incidence of false negative ankle fractures in plain radiographs was small and no complex ankle fractures were missed on radiographs. The total extent of complex fractures was, however, not always obvious on radiographs. In an unselected series of relatively mild ankle injuries, we were unable to show a single case where the treatment or prognosis based on plain radiography should have been significantly altered after having done a routine MRI examination. Plain radiography is still the diagnostic cornerstone of paediatric ankle injuries.

Acute Disease↗