Magnetic resonance measurements of the deviation of the angle of force generated by contraction of the quadriceps muscle in dogs with congenital patellar luxation

OBJECTIVE

To measure the quadriceps angle (Q-angle) in dogs with congenital patellar luxation using magnetic resonance (MR) methods.

STUDY DESIGN

Prospective clinical study.

ANIMALS

Thirty-eight client-owned dogs.

METHODS

Thirty-eight dogs were examined and placed into the following groups based on the degree of patellar instability: normal, grade I, grade II, and grade III. MR images of 37 pelvic limbs without patellar instability, 33 pelvic limbs with patellar luxation, and 6 limbs with cranial cruciate ligament (CrCL) rupture were made. The Q-angle was calculated using trigonometric methods based on MR images. Limbs with patellar luxation were compared with normal stifles and stifle with other disorders.

RESULTS

The average Q-angle of the normal group was 10.5 degrees (24.9 degrees to -2.0 degrees ). The grade I group had an average Q-angle of 12.2 degrees (28.8 degrees to 2 degrees ), the grade II group 24.3 degrees (44.6 degrees to 7.7 degrees ), and the grade III group 36.6 degrees (51.4 degrees to 15.6 degrees ). The average Q-angle of limbs with an isolated CrCL rupture was 19.3 degrees (34.7 degrees to 3.9 degrees ).

CONCLUSION

MR images can be used to make exact calculations of the Q-angle.

CLINICAL RELEVANCE

MR images can be used to quantify the degree of patellar luxation.

Positron emission tomography and lymphoma therapy

FDG-PET is both able to provide information of lymphomatous organ involvement not available by conventional imaging techniques (US, CT, MRI) and to give reliable data otherwise obtainable only by using invasive procedures. As a whole body-screening technique, PET reduces diagnostic requirements and potential complications. Nevertheless the conventional imaging techniques are essential for the exact localisation and correct interpretation of PET findings. A number of factors that may produce false-positive results have to be taken into consideration, including post-treatment inflammatory changes and the sensitivity of the method in the setting of minimal residual disease. Despite its potential of a screening method being performed prior to other imaging procedures, PET is not yet established as a routine element for the primary staging of Hodgkin's disease and non-Hodgkin's lymphoma. Its value for re-staging is less doubtful due to the frequency of stage migration and possible changes in therapy related to the use of PET. Detailed cost-effectiveness studies are needed to assess the economic implications of an expanded use of PET in lymphoma therapy.

[Body structure and radiation exposure in dynamic X-ray studies. A contribution to determining national reference values]

PURPOSE

To contribute data on radiation exposure in dynamic X-ray procedures and to compare them with anthropometric parameters.

METHODS

50 venographies of the lower extremity, 51 abdominal arteriographies, and 121 double contrast examinations of the small bowel were carried out and the dose-area product (DAP) measured for each of the procedures. Additionally, fluoroscopy time, number of shots, body height, body weight, and the sagittal diameter of the examined region were recorded. Dose measurements were statistically evaluated and the following data determined: Frequency distribution, mean, median, 25%- and 75 percentiles as well as correlations with sex, body weight, and diameters.

RESULTS

Median DAP was 587 (men: 540; women: 636) cGycm2 with venography of the lower extremities. DAP/min was better correlated with body weight (r = 0.663) than with diameters of the thigh (r = 0.611). Mean DAP was 14,869 (18,070; 10,980) cGycm2 with abdominal arteriography. DAP/min was badly correlated both with body weight (r = 0.285) and diameters of the abdomen (r = 0.249). Mean DAP was 4527 (5096; 4114) cGycm2 with enteroclysis. DAP/min was well correlated with both body weight (r = 0.621) and diameters of the abdomen (r = 0.628).

CONCLUSION

DAP of venography of the lower extremity and enteroclysis is greatly influenced by the constitution of the patient. The differences between men and women are, however, not as striking as with static X-ray procedures. By contrast, in abdominal arteriography body weight and diameter play a limited role for radiation exposure.

[Body build and radiation exposure in static roentgen studies (I): A contribution for determining a national reference dose value. Promoted by the Federal Office for Radiation Protection (St.Sch 4163)]

PURPOSE

To contribute data on radiation exposure in static x-ray procedures and to compare them with anthropometric parameters.

METHOD

121 chest x-rays and 100 lumbar spine examinations were carried out and the dose-area product (DAP) measured for each of the projections. Additionally, body height, body weight and the sagittal and transversal diameters of the examined regions were recorded. Dose measurements were statistically evaluated and the following data determined: Frequency distribution, median, 25%- and 75%-percentiles as well as correlations with sex, body weight and diameters.

RESULTS

Median DAP was 13 (men: 16; women: 11) resp. 50 (62; 37) cGycm2 with pa resp lateral chest x-ray. Values were closely correlated with body weight (r = 0.704/0.659) and diameter of the chest (r = 0.657/0.579). Median DAP was 175 (239; 126) resp 531 (670; 361) cGycm2 with ap resp lateral lumbar spine examinations. Values were closely correlated with body weight (r = 0.678/0.666) and diameter of the abdomen (r = 0.664/0.658).

CONCLUSIONS

DAP of chest x-rays and lumbar spine examinations is strongly influenced by the constitution of the patients. Men are nearly twice as largely exposed to radiation as women.

[Non-neoplastic hypertrophic osteoarthropathy due to infected aortic prosthesis. Diagnostic imaging aspects]

Secondary hypertrophic osteoarthropathy of the legs is a rare complication of arterial graft surgery. The syndrome is composed of arthralgias, clubbing of the toes and periostosis of the long bones and is usually associated with an infected aortic prosthesis. Often a CT-guided biopsy is performed in order to identify the graft as the primary focus. In addition to the lamellar periostosis demonstrable by conventional radiographs, a vast edema of the bone marrow and surrounding soft tissue is disclosed by MRI. Imaging promotes the early surgical reintervention.

The correlation of canine patellar luxation and the anteversion angle as measured using magnetic resonance images

Measurements from magnetic resonance (MR) images can be used to examine the anteversion angle (AT-angle) and its influence on the lateromedial or mediolateral luxating forces on the patella. The AT-angle of the femoral neck was measured with the aid of MR imaging in 45 pelvic limbs without patellar instability, in 33 limbs with patellar luxation and in 6 limbs with rupture of the cranial cruciate ligament. The limbs with medial patellar luxation were divided into three groups based on clinical examination. The mean (range) AT-angle was 7.6 degrees (0 degrees to 24 degrees) in the "normal" group, 8.6 degrees (-10 degrees to 29 degrees) in the group "grade II," and -0.4 degrees in the group "grade III" (-28 degrees to 12 degrees). A mean (range) AT-angle of 4.8 (-4 degrees to 11 degrees) was measured in the pelvic limbs with rupture of the cranial cruciate ligament. Compared to literature that described AT-angles based on radiographs of normal limbs, reduced AT-angles were found in this study due to different lines of measurement of the femoral neck. This study documents that the AT-angle of the femoral neck does not influence patellar instability. This study also demonstrates that MR images can be used to make exact measurements of the canine AT-angle that represent the true anatomy of the femoral neck.

Craniosynostosis in cherubism

Cherubism is a rare autosomal dominant fibro-osseous disorder that affects almost exclusively maxilla and mandible. Extracranial skeletal involvement is rare. We report on three affected males in three generations. The youngest affected relative was examined at age 4 months. He also had craniosynostosis. His affected father and grandfather had cherubism and clubbing of the fingers. Cherubism was mapped to region 4p16. Because of the associated cranio-synostosis, we excluded the FGFR3 gene as a candidate gene for cherubism.

Primary and secondary Sjögren's syndrome in children--a comparative study

Sjögren's syndrome is a chronic inflammatory systemic autoimmune disease mainly affecting the exocrine and, particularly, the salivary and lacrimal glands. The condition usually occurs in adults. In 1994, the criteria for this syndrome were redefined in a multicenter European study. In children, Sjögren's syndrome is a rare and probably underdiagnosed disease. To date, Sjögren's syndrome in children has only been described in case reports and in the comparative presentation of various study results. So far, no study of a comparative classification into primary and secondary Sjögren's syndrome has been carried out in a patient population of any size. Sjögren's syndrome should be considered in the differential diagnosis of children with recurrent parotitis, keratoconjunctivitis sicca, or pronounced and early tooth decay associated with xerostomia. In this study of 23 children and adolescents under the age of 16 with the clinical symptoms and laboratory findings of Sjögren's syndrome, we differentiate between primary and secondary Sjögren's syndrome. The value of the individual methods of assessing the oral and the ophthalmological components and the manifestation of the underlying rheumatic condition are discussed on the basis of the EULAR criteria. The EULAR diagnostic criteria are of limited applicability in children because reliable anamnestic data are frequently lacking. Another problem in diagnosing Sjögren's syndrome is the short-term detection of serological alterations and clinical symptoms. Even if young patients do not completely fulfill the required criteria, Sjögren's syndrome can be assumed or confirmed in the presence of positive testing for oral and ocular manifestations and recurrent salivary gland enlargement.

Successful treatment of active ankylosing spondylitis with the anti-tumor necrosis factor alpha monoclonal antibody infliximab

OBJECTIVE

Tumor necrosis factor alpha (TNFalpha) has been detected in sacroiliac joint biopsy specimens from patients with spondylarthropathy. The present open pilot study was undertaken to test the efficacy of the anti-TNFalpha monoclonal antibody infliximab in the treatment of active ankylosing spondylitis (AS).

METHODS

Eleven patients with AS of short duration (median 5 years, range 0.5-13 years) that had been active for at least 3 months (range 3-72 months) were treated with 3 infusions of infliximab (at weeks 0, 2, and 6), in a dosage of 5 mg/kg. Ten of the 11 patients had elevated C-reactive protein (CRP) levels (>6 mg/liter) before treatment; these elevations were known to have had persisted > 1 year in at least 3 patients. The Bath AS Disease Activity Index (BASDAI), the Bath AS Functional Index (BASFI), pain as measured on a visual analog scale, and the Bath AS Metrology Index (BASMI) were assessed. Quality of life was assessed using the Short Form 36 instrument. Laboratory markers of disease activity, including interleukin-6 (IL-6) levels, were determined. Dynamic magnetic resonance imaging (MRI) of the spine was performed in 5 patients.

RESULTS

One patient withdrew from the study due to the occurrence of urticarial xanthoma 8 days after the first infusion. At study enrollment, 3 of 5 patients had evidence of spinal inflammation (spondylitis and spondylodiscitis) as detected by MRI; followup MRI 2-6 weeks after the third infusion revealed improvement in 2. Improvement of > or = 50% in activity, function, and pain scores was documented in 9 of 10 patients; the median improvement in the BASDAI after 4 weeks was 70% (range 41-94%). This clear-cut benefit lasted for 6 weeks after the third infusion in 8 of 10 patients. The median CRP level decreased from 15.5 mg/liter (range <6-90.8) to normal, and the median IL-6 level from 12.4 mg/liter (range 0-28.4) to normal (<5). There was improvement in all 9 SF-36 concepts; the improvement was significant for 6 concepts.

CONCLUSION

These data suggest that anti-TNFalpha therapy is very effective for several weeks in AS. Whether this therapy, in addition to its antiinflammatory effect, prevents ankylosis remains to be determined.

[Decision analysis in radiology using Markov models]

Markov models (Multistate transition models) are mathematical tools to simulate a cohort of individuals followed over time to assess the prognosis resulting from different strategies. They are applied on the assumption that persons are in one of a finite number of states of health (Markov states). Each condition is given a transition probability as well as an incremental value. Probabilities may be chosen constant or varying over time due to predefined rules. Time horizon is divided into equal increments (Markov cycles). The model calculates quality-adjusted life expectancy employing real-life units and values and summing up the length of time spent in each health state adjusted for objective outcomes and subjective appraisal. This sort of modeling prognosis for a given patient is analogous to utility in common decision trees. Markov models can be evaluated by matrix algebra, probabilistic cohort simulation and Monte Carlo simulation. They have been applied to assess the relative benefits and risks of a limited number of diagnostic and therapeutic procedures in radiology. More interventions should be submitted to Markov analyses in order to elucidate their cost-effectiveness.

Diagnostic value of sialography with both the conventional and digital subtraction techniques in children with primary and secondary Sjögren's syndrome

OBJECTIVE

The application of anamnestic data on siccative symptoms required for classifying adult Sjögren's syndrome is limited in childhood. Instrumental test procedures are therefore necessary for objectively recording the oral and ophthalmologic manifestations of the disease. The aim of this study was to clarify the sialographic changes that occur in Sjögren's syndrome in children.

STUDY DESIGN

A total of 23 sialograms were obtained with both conventional and digital subtraction techniques in 21 children with primary (10 girls and 1 boy) or secondary Sjögren's syndrome (10 girls). The films were assessed by 3 physicians and submitted for a consensus analysis if necessary.

RESULTS

The pathologic features observed in the children varied from a slightly narrowed ductal system to multiple peripheral ductal ectasias and completely destroyed parenchyma. Sialographic examinations demonstrate that, with progressing disease, regression of acinar dilatations and rarification of the ductal system occur.

CONCLUSION

The results show that the spectrum of sialographically recordable lesions in Sjögren's syndrome in children is greater than is described thus far in the literature.

[Statistical analysis of German radiologic periodicals: developmental trends in the last 10 years]

PURPOSE

To identify which statistical tests are applied in German radiological publications, to what extent their use has changed during the last decade, and which factors might be responsible for this development.

MATERIALS AND METHODS

The major articles published in "ROFO" and "DER RADIOLOGE" during 1988, 1993 and 1998 were reviewed for statistical content. The contributions were classified by principal focus and radiological subspecialty. The methods used were assigned to descriptive, basal and advanced statistics. Sample size, significance level and power were established. The use of experts' assistance was monitored. Finally, we calculated the so-called cumulative accessibility of the publications.

RESULTS

525 contributions were found to be eligible. In 1988, 87% used descriptive statistics only, 12.5% basal, and 0.5% advanced statistics. The corresponding figures in 1993 and 1998 are 62 and 49%, 32 and 41%, and 6 and 10%, respectively. Statistical techniques were most likely to be used in research on musculoskeletal imaging and articles dedicated to MRI. Six basic categories of statistical methods account for the complete statistical analysis appearing in 90% of the articles. ROC analysis is the single most common advanced technique. Authors make increasingly use of statistical experts' opinion and programs.

CONCLUSIONS

During the last decade, the use of statistical methods in German radiological journals has fundamentally improved, both quantitatively and qualitatively. Presently, advanced techniques account for 20% of the pertinent statistical tests. This development seems to be promoted by the increasing availability of statistical analysis software.

[Benefits, costs and analysis in diagnostic radiology: definitions and glossary]

Cost efficiency analyses in clinical radiology require the application of methods and techniques that are not yet part of the academic qualifications of the specialists. The procedures used are borrowed from economics, decision theory, applied social sciences, epidemiology and statistics. Many expressions hail from the angloamerican literature and are presently not yet germanized unequivocally. This survey is intended to present main terms of cost efficiency analysis in the english version as well as a german translation, to give a clear definition and, if necessary, explanatory notes, and to illustrate their application by means of concrete radiologic examples. The selection of the terms is based on the hierarchical models of health technology assessment resp. clinical outcome research by Fryback & Thornbury resp. Maisey & Hutton. In concrete terms, both the differences between benefit, outcomes, and utility and the differences between effectiveness, efficacy and efficiency and the differences between direct, indirect, intangible, and marginal costs are explained. True cost efficiency analysis is compared with cost effectiveness analysis, cost identification analysis, cost minimization analysis, and cost utility analysis. Applied social sciences are represented by the Medical Outcomes Study Short Form-36 and the QALY conception. From decision theory both the analysis of hypothetical alternatives and the Markov model are taken. Finally, sensitivity analysis and the procedures of combined statistical evaluation of comparable results (meta-analysis) are quoted.