Ultrasonography (US) is often the initial imaging modality employed in the evaluation of renal diseases. Despite improvements in B-mode and Doppler imaging, US still faces limitations in the assessment of focal renal masses and complex cysts as well as the microcirculation. The applications of contrast-enhanced US (CEUS) in the kidneys have dramatically increased to overcome these shortcomings with guidelines underlining their importance. This article describes microbubble contrast agents and their role in renal imaging. Microbubble contrast agents consist of a low solubility complex gas surrounded by a phospholipid shell. Microbubbles are extremely safe and well-tolerated pure intravascular agents that can be used in renal failure and obstruction, where computed tomographic (CT) and magnetic resonance (MR) imaging contrast agents may have deleterious effects. Their intravascular distribution allows for quantitative perfusion analysis of the microcirculation, diagnosis of vascular problems, and qualitative assessment of tumor vascularity and enhancement patterns. Low acoustic power real-time prolonged imaging can be performed without exposure to ionizing radiation and at lower cost than CT or MR imaging. CEUS can accurately distinguish pseudotumors from true tumors. CEUS has been shown to be more accurate than unenhanced US and rivals contrast material-enhanced CT in the diagnosis of malignancy in complex cystic renal lesions and can upstage the Bosniak category. CEUS can demonstrate specific enhancement patterns allowing the differentiation of benign and malignant solid tumors as well as focal inflammatory lesions. In conclusion, CEUS is useful in the characterization of indeterminate renal masses and cysts.
Treatments for gynecologic cancer usually result in loss of fertility due to surgery or radical radiation therapy in the pelvis. In countries with an established screening program for cervical cancer, the majority of gynecologic malignancies occur in postmenopausal women. However, a substantial number of affected women are of childbearing age and have not completed their families. In these younger women, consideration of fertility preservation may be important. This article describes the fertility-sparing treatment options that are currently available and outlines the role of imaging in the selection of eligible patients on the basis of a review of the literature. In the setting of cervical cancer, magnetic resonance (MR) imaging is used to delineate the size, position, and stage of the tumor for selection of patients who are suitable for radical trachelectomy. In patients with solitary complex adnexal masses, diffusion- and perfusion-weighted MR imaging sequences are used to categorize the likelihood of invasive or borderline malignancy for consideration of unilateral ovarian resection, with fertility preservation when possible. In patients with endometrial cancer, MR imaging is used to rule out signs of invasive disease before hormone therapy is considered. Imaging is also used at patient follow-up to detect recurrent disease; however, evidence to support this application is limited. In conclusion, imaging is an essential tool in the care of patients with gynecologic malignancies who are considering fertility-preserving treatment options. RSNA, 2016.
Locally advanced and node-positive cervical cancers are usually treated with external beam radiation therapy and intracavitary brachytherapy with concomitant chemotherapy. In patients with locally advanced cervical cancer, imaging plays a vital role in pretreatment planning, assessment of primary tumor response to treatment, follow-up, and evaluation of treatment-related complications. Radiation therapy planning is crucial to successful local and regional control of disease. Patient selection criteria for radiation therapy with concomitant chemotherapy are described, as is assessment of treatment response of the primary cervical tumor at magnetic resonance (MR) imaging. Image interpretation can be challenging because of radiation therapy-related changes in the pelvic organs. Expected changes in the bladder, bowel, and bone marrow after radiation therapy are described, and multimodality imaging findings at computed tomography, MR imaging, and fluorine 18 fluorodeoxyglucose positron emission tomography are illustrated. Complications after radiation therapy have declined over recent years because of targeted radiation therapy. These complications can be divided into acute and chronic effects, where acute toxic effects occur within weeks of treatment. Chronic complications include cervical stenosis, small bowel stricture, fistula formation, and insufficiency fractures. Imaging is an essential tool in the care of patients with cervical cancer treated with chemotherapy and radiation therapy. The reporting radiologist should be familiar with the expected imaging appearances of the pelvic organs after radiation therapy, as well as potential complications, to avoid pitfalls in image interpretation.
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