To develop an optimized interpretation strategy of dynamic contrast enhanced breast MRI based on a combination of quantitative and qualitative criteria, the features of 120 histopathologically verified lesions were retrospectively analysed on contrast enhanced dynamically acquired (before and 1, 2, 4 and 7 min following injection of 0.2 mmol kg-1 gadolinium-DOTA) three-dimensional gradient echo images. Quantitative criteria, based on relative signal intensity measurements and qualitative morphological features, including lesion shape, margins and enhancement patterns were analysed in regard to differentiating malignant (n = 70) from benign (n = 50) lesions. Quantitative assessment of enhancement profiles was most accurate when analysis was based on early 1 min measurements. Using a 90% threshold, sensitivity and specificity in detecting breast cancer were 83% and 66%, respectively. When based on qualitative morphological analysis alone, sensitivity and specificity were 83% and 54%. Combined quantitative and qualitative assessment yielded a considerably higher sensitivity, specificity and accuracy of 93%, 74% and 85%, respectively. In conclusion, results from dynamic contrast enhanced breast MRI can be improved by basing the interpretation on both quantitative and qualitative criteria.

The detection of characteristic radiographic signs in CAPD patients presenting with symptoms of intestinal obstruction may suggest the presence of severe SP and should lead to cautious surgical interventions.

The aim of this study was to compare the diagnostic performance of conventional mammography and dynamic contrast-enhanced fast 3D gradient-echo (GRE) MRI regarding the detection and characterization of breast lesions relative to histopathologic analysis and to assess the results of a combined evaluation of both methods. fifty consecutive patients with 63 histopathologically verified breast lesions underwent dynamic contrast-enhanced GRE MRI in addition to routine conventional mammography. All lesions were classified by both methods on a five-point scale as benign or malignant, and the results were correlated to histopathology. Conventional mammography and dynamic MRI yielded a sensitivity and specificity of 82 and 64 %, and 92 and 76 %, respectively. The difference between the results was statistically not significant (p > 0.05) with areas under the receiver-operating-characteristics curves of 0.807 for mammography and 0.906 for MR imaging. Combination of the results of both methods slightly increased the sensitivity for detection of breast cancer to 95 % but decreased specificity to 52 %. In this selected patient subset, including only patients referred for excisional biopsy, contrast-enhanced dynamic MRI proved more sensitive and specific than conventional mammography regarding the detection of malignancy. While a combination of both methods yields a slightly improved sensitivity, specificity is vastly reduced.

No abstract

Dynamic contrast-enhanced 3D MRA of the pulmonary arteries can be used to delineate pulmonary arterial angiosarcomas preoperatively. Considerable variability of contrast agent uptake reflects the wide histologic behavior of these masses in differentiation from central pulmonary embolism.

The purpose of this study was to evaluate and compare the diagnostic performance of stereolithography vs workstation-based three-dimensional (3D) reformations in intra-articular calcaneal fractures. A total of 30 intra-articular calcaneal fractures were examined using standard radiographs, coronal CT scans, and 2D and 3D reformations. The CT data were transferred to an outside institution, and stereolithograms were produced from photopolymer resin employing a laser beam system. 3D reformations and stereolithograms were analyzed in a blinded fashion by two staff radiologists. Receiver-operating-characteristic (ROC) curves were obtained for six clinically significant fracture components. Standard radiographs, coronal CT scans, and 2D reformations served as the standard of reference. The area under the ROC curves for 3D reformations and stereolithograms were 1.0 and 0.98 for abnormal tuber angles, 0.91 and 0.91 for anterior and middle talo-calcaneal joint involvement, 0. 90 and 0.95 for involvement of the posterior talo-calcaneal joint, 0. 65 and 0.78 for the presence of a lateral bulge, 0.80 and 0.81 for the involvement of the calcaneocuboidal joint, and 0.62 and 0.67 for the presence of a "tongue-type" fracture. No statistically significant difference was demonstrated for the two methods (Wilcoxon signed-rank test, p = 0.138). Based on our results stereolithograms did not prove to be statistically superior to workstation-based 3D reformations. Stereolithograms may still be useful for teaching purposes and for surgical planning at a thinking-efficacy level.

No abstract

Basal serum thyroxine (T 4 ) concentration and the thyrotropin-releasing hormone (TRH) stimulation test were used to assess thyroid function in 36 critically ill cats examined between July 1996 and October 1998. Of the 36 cats, hyperthyroidism (as underlying or complicating disease) was suspected in 22 based on clinical signs, palpable thyroid nodules, and abnormal thyroid gland histology (study group). Hyperthyroidism was not suspected in the remaining 14 cats, which served as the control group. Based on serum T 4 concentrations, suppression of thyroid function was documented in 14 (64%) cats of the study group and in 10 (71%) cats of the control group. The TRH stimulation test revealed an increase in serum T 4 of less than 50% of the baseline concentration in 18 (82%) cats of the study group, and in 6 (43%) cats of the control group. In conclusion, based on the results of serum T 4 determinations and the TRH stimulation tests, it was not possible to differentiate between cats with clinical and histologic evidence of thyroid dysfunction (hyperthyroidism) and cats with severe nonthyroidal illnesses.Key words: Hyperthyroidism; Nonthyroidal illness; Thyroid function tests. The influence of severe nonthyroidal illness on the hypothalamic-pituitary-thyroid axis and thyroid hormone metabolism has been studied extensively in humans.1-5 A variety of alterations in the hypothalamic-pituitary-thyroid axis function including subnormal serum thyroxine (T 4 ) or triiodothyronine (T 3 ) concentrations or both, subnormal or high free T 4 concentrations, and subnormal thyroid-stimulating hormone (TSH) occur in critically ill euthyroid humans; this condition was termed ''euthyroid sick syndrome.'' 1,2,6-8 Typically these changes abate once the underlying illness resolves. A similar condition was recently reported in cats; T 4 concentrations were subnormal in 21-59% of euthyroid cats with nonthyroidal illnesses. 9,10 Overt hyperthyroidism in humans is generally easy to diagnose and is evidenced by high T 4 and T 3 , and low TSH concentrations. 6,8,11 However, in some clinical situations, results of either test may fall within the reference range. 15 Therefore, it has been postulated that in cats with nonthyroidal disease, T 4 concentrations in the low-normal or in the subnormal range are sufficient to exclude hyperthyroidism. 9,16 To date, no assay is available for feline TSH and, thus, changes in T 4 concentrations during function tests are used to determine thyroid status in the cat. Administration of TRH has been shown consistently to increase T 4 concentrations in healthy cats and the TRH stimulation test has been advocated to discriminate healthy cats and sick euthyroid cats from mildly hyperthyroid cats with normal T 4 concentration. 16 For differentiation of hyperthyroid and euthyroid cats, absolute changes of T 4 concentration were of limited value compared to relative changes. A relative increase in T 4 greater than 60% of the baseline concentration was considered consistent with euthyroidism, whereas increase in T ...