Dual energy CT allows for improved characterization of response to antiangiogenic treatment in patients with metastatic renal cell cancer.

OBJECTIVES: To evaluate the potential role of dual energy CT (DECT) to visualize antiangiogenic treatment effects in patients with metastatic renal cell cancer (mRCC) while treated with tyrosine-kinase inhibitors (TKI). METHODS: 26 patients with mRCC underwent baseline and follow-up single-phase abdominal contrast enhanced DECT scans. Scans were performed immediately before and 10 weeks after start of treatment with TKI. Virtual non-enhanced (VNE) and colour coded iodine images were generated. 44 metastases were measured at the two time points. Hounsfield unit (HU) values for VNE and iodine density (ID) as well as iodine content (IC) in mg/ml of tissue were derived. These values were compared to the venous phase DECT density (CTD) of the lesions. Values before and after treatment were compared using a paired Student's t test. RESULTS: Between baseline and follow up, mean CTD and DECT-derived ID both showed a significant reduction (p < 0.005). The relative reduction measured in percent was significantly greater for ID than for CTD (49.8 ± 36,3 % vs. 29.5 ± 20.8 %, p < 0.005). IC was also significantly reduced under antiangiogenic treatment (p < 0.0001). CONCLUSIONS: Dual energy CT-based quantification of iodine content of mRCC metastases allows for significantly more sensitive and reproducible detection of antiangiogenic treatment effects. KEY POINTS: • A sign of tumour response to antiangiogenic treatment is reduced tumour perfusion. • DECT allows visualizing iodine uptake, which serves as a marker for vascularization. • More sensitive detection of antiangiogenic treatment effects in mRCC is possible.

Can single-phase dual-energy CT reliably identify adrenal adenomas?

PURPOSE: To evaluate whether single-phase dual-energy-CT-based attenuation measurements can reliably differentiate lipid-rich adrenal adenomas from malignant adrenal lesions. MATERIALS AND METHODS: We retrospectively identified 51 patients with adrenal masses who had undergone contrast-enhanced dual-energy-CT (140/100 or 140/80 kVp). Virtual non-contrast and colour-coded iodine images were generated, allowing for measurement of pre- and post-contrast density on a single-phase acquisition. Adrenal adenoma was diagnosed if density on virtual non-contrast images was ≤10 HU. Clinical follow-up, true non-contrast CT, PET/CT, in- and opposed-phase MRI, and histopathology served as the standard of reference. RESULTS: Based on the standard of reference, 46/57 (80.7%) adrenal masses were characterised as adenomas or other benign lesions; 9 malignant lesions were detected. Based on a cutoff value of 10 HU, virtual non-contrast images allowed for correct identification of adrenal adenomas in 33 of 46 (71%), whereas 13/46 (28%) adrenal adenomas were lipid poor with a density ≥10 HU. Based on the threshold of 10 HU on the virtual non-contrast images, the sensitivity, specificity, and accuracy for detection of benign adrenal lesions was 73%, 100%, and 81% respectively. CONCLUSION: Virtual non-contrast images derived from dual-energy-CT allow for accurate characterisation of lipid-rich adrenal adenomas and can help to avoid additional follow-up imaging. KEY POINTS: • Adrenal adenomas are a common lesion of the adrenal glands. • Differentiation of benign adrenal adenomas from malignant adrenal lesions is important. • Dual-energy based virtual non-contrast images help to evaluate patients with adrenal adenomas.

Non specific serological reactions in the diagnosis of bovine brucellosis: experimental oral infection of cattle with repeated doses of Yersinia enterocolitica O:9.

Eight heifers were orally infected with 4 x 10(9) colony forming units of a field cattle strain of Yersinia enterocolitica O:9 in a capsule, 5 days a week, for about 9 weeks (day 0-day 64 (D0-D64). The faecal shedding of Y. enterocolitica O:9 began on D5 for seven out of the eight challenged cattle with a high level of excretion during the first month, followed by a decrease till the day of slaughter (D76). Y. enterocolitica O:9 was not isolated from organs collected at slaughter. No clinical symptoms were observed. Hyperplasia of intestinal lymph formations was the sole microscopic lesions observed. Five animals showed a serological reaction against Brucella antigens in at least one of the following tests: Rose-Bengal test, complement fixation test, tube agglutination test or indirect ELISA (iELISA) tests. Only one animal showed a high level of serological response and a positive reaction in the dithiothreitol-microagglutination test. The observed variability in terms of individual sensitivity to the Y. enterocolitica O:9 infection is in agreement with the low individual prevalence rate and the transient serological reaction and faecal Y. entercolitica O:9 shedding observed in herds showing false positive serological reactions in brucellosis.