Interpretation Of Sonograms Research Articles

Clinical utility of carotid and transcranial ultrasound in cerebrovascular diseases

Clinical utility of carotid and transcranial ultrasound in cerebrovascular diseases Lívia Figueiredo, Viviane F Zétola, Marcos C Lange Neurology Division, Hospital de Clínicas, Universidade Federal do Paraná, Curitiba, Brazil Abstract: Carotid and transcranial (CTU) ultrasound is a useful tool in a number of clinical settings, particularly in cerebrovascular diseases. CTU is the only method that provides real-time determination of velocity and the spectral waveform of blood flow in the extracranial and basal intracranial arteries, and is effective in the detection of stenosis and occlusion. When transcranial ultrasound is considered, CTU is the only method that allows visualization of microembolic signals in the intracranial arteries. CTU makes a rapid differential diagnosis possible, improving therapeutic decision-making in acute stroke and determining the risk of recurrence and prognosis based on its findings. It is also the standard of care in children with sickle cell disease, when selecting patients for chronic blood transfusion, and for reducing the risk of ischemic stroke in these patients. CTU has some advantages, ie, relative simplicity in terms of interpretation and performance, and affordability, noninvasiveness, and portability. The main concern with ultrasound is that it is an operator-dependent tool and requires a high level of expertise and knowledge of three-dimensional cerebrovascular anatomy for correct interpretation of sonograms. The most significant limitation of intracranial evaluation by transcranial ultrasound is the absence of a suitable bone window in approximately 10% of patients. This paper gives an overview of the current utility and importance of CTU in the prevention and evaluation of ischemic cerebrovascular disease. Keywords: transcranial Doppler ultrasonography, Doppler ultrasonography duplex, cerebrovascular disorders, stroke

Compensation for phase and amplitude imbalance in quadrature Doppler signals

Quadrature phase detection is widely used in ultrasound Doppler systems to obtain directional information about flow velocities in blood vessels. The presence of phase and/or gain imbalance between the quadrature outputs produces crosstalk between the forward and reverse channels which may introduce errors into mean and maximum velocity estimates and hamper the interpretation of sonograms. This technical note describes the assessment of the crosstalk in a commercial pulsed-wave Doppler system, and suggests methods of compensation for the causative imbalance which can be implemented using digital signal processing techniques. Examples of applying these methods to the outputs of the commercial system are given.

Scrotal Sonography in Normal Subjects

To document the frequency of epididymal and testicular abnormalities in asymptomatic men, scrotal sonography was performed on 75 men ranging in age from 10 to 84 years. Epididymal cysts larger than 3 mm in size were found in 23% of the patients, hydroceles in 23%, varicoceles (tortuous vessels ×3 mm in diameter) in 11%, testicular cysts in 4%, atrophy in 3%, and calcifications in 3%. The high prevalence of these findings can complicate the interpretation of sonograms of the symptomatic scrotum.

Pathologic Basis of the Sonographic Appearance of the Normal and Malignant Prostate

The hypoechoic nature of prostatic cancer is now well recognized. In fact, not all cancers are purely hypoechoic; many are isoechoic, and some have a mixed echogenicity. Rarely, we have seen a cancer that was predominantly hyperechoic. Other signs of disturbance of the normal internal anatomy of the prostate may suggest the diagnosis of prostate cancer and are particularly valuable in assessing patients with more advanced disease. Approximately one third of early-stage cancers detected by palpation or transurethral resection are isoechoic. These tumors are anteriorly located, small, and well differentiated and infiltrate among normal glands or are composed of malignant glands similar in size to normal acini. Not all hypoechoic areas within the prostate are cancer; both normal anatomic structures and various benign conditions may appear less echogenic than the normal prostatic parenchyma. A comprehensive understanding of normal prostatic anatomy and the morphology of prostate cancer is essential to the accurate interpretation of the sonogram. Precise interpretation of prostatic sonograms requires detailed correlations of high-quality images with pathologic examinations of the whole prostate. The development of accurate criteria for the sonographic diagnosis of both malignant and benign prostatic diseases can be achieved only by such studies. As the possibilities and limitations of transrectal ultrasonography become apparent from pathologic correlation, the role of ultrasound in the diagnosis of prostate cancer will be placed on a more rational basis.

Detection of arterial defects by real-time ultrasound scanning during vascular surgery: An experimental study

Real-time ultrasound B-mode scanning was used experimentally to detect vascular defects resembling those which might occur in arterial reconstructive surgery. The lesions established were arterial strictures, subintimal hematomas, intimal flaps, and thrombi attached to the arterial wall. All types of lesions were readily identified by direct contact ultrasonography. Ultrasonography was evaluated in terms of qualitative and quantitative assessment. Qualitatively, 68% of 1 × 5-mm flaps and 100% of all larger flaps were detected. There were no false positive ultrasound diagnoses in the interpretation of sonograms from normal arterial segments. Quantitatively, ultrasonic estimation of flap size correlated with actual flap dimensions with a coefficient of correlation of 0.84 ( P < 0.001). This study indicates that operative ultrasound to detect relatively small vascular defects at arterial operative sites is a feasible procedure which should be evaluated in clinical application.