Quality assurance of ultrasound systems: current status and review of literature.

Diagnostic ultrasound (US) images can be obtained from a quality device, in optimal working conditions, combined with the capable actions of the operator in tweaking the equipment's characteristics. The quality assurance (QA) is the topic of this review article, and it is addressed in an US practice through proper selection of the equipment when purchasing, and through care and preventive maintenance of the machine for ensuring accurate performance. For optimal US system functioning, QA steps carried out on the basis of a scheduled program are needed in any US practice or department. It is critical to confirm in a semiannual or annual basis that the image quality is maintained according to standards and any subtle change in equipment's functioning is detected and amended at an early stage. The use of test objects (also called US testing phantoms) is required above the basic level of QA testing. The scope of this review article is to inform the US user about necessary QA knowledge and at the same time, present the state of the art of the most suitable test methods for US QA. We referred to relevant publications, selected after performing a systematic literature search of the MEDLINE, EMBASE and COCHRANE databases, and also to the standards established by authoritative international societies.

CEUS in the study of bladder, method, administration and evaluation, a technical note.

PURPOSE: Contrast-enhanced ultrasound (CEUS) is the application of ultrasound contrast agents (UCAs) to traditional medical sonography. The development of UCAs allowed to overcome some of the limitations of conventional B-mode and Doppler ultrasound techniques and enabled the display of the parenchymal microvasculature. Purpose of this paper is to delineate the elements of a solid and science-based technique in the execution of urinary bladder CEUS. METHODS: We describe the technical execution of urinary bladder CEUS and the use of perfusion softwares to perform contrast enhancement quantitative analysis with generation of time-intensity curves from regions of interest. RESULTS: During CEUS, normal bladder wall shows a wash-in time of 13 s, a time to peak (TTP) >40 s, a signal intensity (SI) <45 % and a wash-out time >80 s; Low-grade urothelial cell carcinoma (UCC) shows a wash-in time of 13 s, a time to peak TTP >28 s, a SI <45 % and a wash-out time of 40 s; High-grade UCC shows a wash-in time of 13 s, a TTP >28 s, a SI >50 % and a wash-out time of 58 s. CONCLUSIONS: CEUS is a useful tool for an accurate characterization of bladder UCC although it has some drawbacks. To avoid misunderstandings, a widely accepted classification and a standardized terminology about the most significant parameters of this application should be adopted in the immediate future.

Elastographic and contrast-enhanced ultrasound features of a benign schwannoma of the common fibular nerve.

Differential diagnosis of a mass in the popliteal fossa includes a number of pathologies, such as Baker's cyst, extra-articular ganglia cyst, hematoma, proliferation of adipose tissue, aneurysm of the popliteal artery, thrombosed varicose vein, gouty tophi and benign or malignant soft tissue tumors. Schwannoma is the most common benign peripheral nerve tumor. However, only a few authors have so far reported on schwannomas located on the common fibular nerve. The aim of this paper is to present contrast-enhanced ultrasound and ultrasound elastographic features of a rare case of schwannoma of the common fibular nerve as well as imaging features of a schwannoma of the peripheral nerve.