Dual-energy computed tomographic (DECT) technology offers enhanced capabilities that may benefit oncologic imaging in the abdomen. By using two different energies, dual-energy CT allows material decomposition on the basis of energy-dependent attenuation profiles of specific materials. Although image acquisition with dual-energy CT is similar to that with single-energy CT, comprehensive postprocessing is able to generate not only images that are similar to single-energy CT (SECT) images, but a variety of other images, such as virtual unenhanced (VUE), virtual monochromatic (VMC), and material-specific iodine images. An increase in the conspicuity of iodine on low-energy VMC images and material-specific iodine images may aid detection and characterization of tumors. Use of VMC images of a desired energy level (40-140 keV) improves lesion-to-background contrast and the quality of vascular imaging for preoperative planning. Material-specific iodine images enable differentiation of hypoattenuating tumors from hypo- or hyperattenuating cysts and facilitate detection of isoattenuating tumors, such as pancreatic masses and peritoneal disease, thereby defining tumor targets for imaging-guided therapy. Moreover, quantitative iodine mapping may serve as a surrogate biomarker for monitoring effects of the treatment. Dual-energy CT is an innovative imaging technique that enhances the capabilities of CT in evaluating oncology patients.

extrinsic ureteric compression in nine cases (8.3%), benign extrinsic ureteric compression in two cases (1.9%), pelvic-ureteric junction obstruction in two cases (1.9%), vesicoureteric junction (VUJ) obstruction in one case (0.9%), bladder outlet obstruction in one case (0.9%) and iatrogenic causes in four cases (3.7%).• No definitive cause was found in nine cases (8.3%). For patients in whom a ureteric stone was the cause of forniceal rupture, the level of obstruction was proximal ureter in 24.3% of cases, distal ureter in 17.6% of cases and VUJ in 58.1% of cases.• Mean ( SD ) stone size was 4.09 (2.0) mm. Mean ( SD ) stone size was 5.34 (1.87) mm for proximal stones, 4.08 (1.69) mm for distal stones and 3.53 (1.96) mm for VUJ stones ( P = 0.005).• Urinary tract infection was present in five out of 97 patients (5.2%) in whom data were available for analysis. CONCLUSION• The most common aetiology of renal forniceal rupture is obstruction caused by distal ureteric stones followed by malignant extrinsic ureteric compression.

In advanced HCC, CTP is a more sensitive image biomarker for monitoring early antiangiogenic treatment effects as well as in predicting outcome at the end of treatment and progression-free survival as compared with RECIST and tumor density.

Image quality improvements with ASIR at reduced radiation dose of 1.8 mGy enabled effective evaluation of urinary calculi without substantially affecting diagnostic confidence. © RSNA, 2012.