This paper provides a new design of 12-element array ultrasound transducer. By modeling the beam field model of single element and array and comparing simulated and real ultrasound beam field test data, it can be demonstrated that 12-element array ultrasound transducer has a much better field performance than the 8-element transducer.
Equipment Design ; Ultrasonography, Doppler ; instrumentation ; Ultrasonography, Prenatal ; instrumentation

In this paper the theory of autocorrelation algorithm for color flow mapping is analyzed and a new way for ultrasound color flow velocity estimation and real-time display is proposed. The method sets up a mapping table which directly relates to the dynamic display range and has only 256 entries using an inverse mapping method instead of calculating the arctangent value directly. This method is ideal for software implementation and offers an interactive way to the user for changing the dynamic range of flow velocity and thus to increasing the display resolution.
Algorithms ; Blood Flow Velocity ; Humans ; Pulsatile Flow ; physiology ; Rheology ; instrumentation ; Ultrasonography, Doppler, Color ; instrumentation ; methods

To evaluate the possibility and accuracy of Doppler tissue image (DTI) on assessment of normal and abnormal ventricular activation and contraction sequence, 9 open chest canine hearts were analyzed by acceleration mode, M-mode, and spectrum mode DTI. Our results showed that: (1) Acceleration mode DTI could show the origin of activation and conduction sequence on line; (2) M-mode DTI revealed that the activation in mid-interventricular septum was earlier than that in mid-left ventricular posterior wall at sinus activation; (3) Spectrum DTI showed the ventricular endocardium was activated earlier than the ventricular epicardium in all segments at sinus rhythm. The earliest site of activation of the normal ventricular wall was at middle interventricular septum; the latest site was at basal-posterior wall; the contraction sequence was different at the different walls; (4) During abnormal ventricular activation, mid-left ventricular posterior wall was activated earliest in accordance with the pacing sites. Abnormal ventricular activation was slower than sinus activation, and the contraction sequence varied at different sites of ventricular wall. It is concluded that DTI can be used to localize the origin of normal or abnormal myocardial activation and to assess the contraction sequence conveniently, accurately and non-invasively.
Echocardiography, Doppler/instrumentation ; Echocardiography, Doppler/*methods ; Heart Ventricles/*ultrasonography ; Myocardial Contraction/*physiology ; Sinoatrial Node/physiology ; Tachycardia/physiopathology ; Tachycardia/ultrasonography

BACKGROUNDS/AIMS: Doppler ultrasongraphy is used to evaluate hemodynamic alternations in patients with liver cirrhosis. Purpose of this study was to determine the interequipment variability of Doppler indices in portal and splenic vein in cirrhosis. METHODS: Blood velocity, diameter, flow and congestive index in portal and splenic vein were measured by Doppler ultrasonography in 30 patients with cirrhosis using two different machines. RESULTS: Portal venous velocities measured by HDI-5000 and SSD-5000 were 8.72+/-3.69 cm/sec, 12.21+/-2.84 cm/sec, respectively which showed significant difference (P<0.001). Measured portal blood flows and congestive indices also had significant difference between HDI-5000 and SSD-5000 (P<0.01). Splenic venous velocity by HDI-5000 was 8.55+/-2.71 cm/sec, which was lower than that of 12.32+/-3.11 cm/sec by SSD-5000 (P<0.001). Splenic blood flows measured by HDI-5000 and SSD-5000 were 390.73+/-260.98 mL/min, 595.01+/-346.53 mL/min, respectively, showing significant difference (P=0.015). However, no differences were in the diameters of portal and splenic vein between HDI-5000 and SSD-5000. CONCLUSION: Doppler indices in portal and splenic vein showed significant interequipment variability. Therefore, in liver cirrhosis, hemodynamic investigations using different Doppler ultrasonographic machines is inappropriate.
Adult ; Aged ; Blood Flow Velocity ; Female ; Humans ; Liver Cirrhosis/*ultrasonography ; Male ; Middle Aged ; Ultrasonography, Doppler/*instrumentation

OBJECTIVETo evaluate the diagnostic value of ultrasonography in combination with mammography for breast cancer within 2 cm.

METHODSThe PubMed, the Cochrane Library, CNKI, CBM and Wanfang databases (2003/01/01-2013/04/30) were searched for studies of the diagnostic value of ultrasonography in combination with mammography for breast cancer within 2 cm. The quality of the included studies was evaluated according to QUADAS items. The pooled sensitivity (SEN), pooled specificity (SPE), pooled diagnostic odds ratio (DOR), and area under summary receiver operating characteristic curve (AUC) were calculated using Review Manager 5.2 and Meta-DiSc 1.4 software.

RESULTSNine articles were included in the final analysis. The pooled SEN of ultrasonography, mammography and their combination were 0.75, 0.66, and 0.92, the pooled SPE 0.75, 0.83, and 0.82, the pooled DOR 7.11, 8.67, and 60.82, and the AUC 0.7902, 0.8120, and 0.9469, respectively.

CONCLUSIONThe combination of ultrasonography and mammography can increase the diagnostic accuracy for breast cancer within 2 cm.

Breast Neoplasms ; diagnostic imaging ; pathology ; Early Detection of Cancer ; Female ; Humans ; Mammography ; instrumentation ; methods ; Molybdenum ; ROC Curve ; Sensitivity and Specificity ; Ultrasonography, Doppler, Color ; Ultrasonography, Doppler, Pulsed ; Ultrasonography, Mammary ; methods

The paper presents the development and design of an ultrasonic Doppler fetal heart rate monitoring system based on DSP, and explains the realization of a algorithm for detecting fetal heart rate. Clinical practice has proved that this system is able to pick up the real-time fetal heart rate correctly and rapidly.
Algorithms ; Fetal Monitoring ; instrumentation ; methods ; Heart Rate, Fetal ; physiology ; Humans ; Sensitivity and Specificity ; Signal Processing, Computer-Assisted ; Ultrasonography, Doppler ; instrumentation ; methods ; Ultrasonography, Prenatal ; instrumentation ; methods

In color flow imaging systems, the ultrasound Doppler signal scattered from blood is heavily corrupted by the strong clutter signal reflected from the slow-moving muscular tissue. Moving target indicator (MTI) is a key technique of rejecting the clutter signal and detecting blood flow. To improve the performance of detecting blood flow, a new MTI scheme is proposed in this paper. It consists of a pre-filter, a clutter weak-rejector and a 2-order AR estimator. After the processing of pre-filtering and clutter weak-rejection, the strong clutter signal is effectively eliminated and its strength is comparable with blood flow. Under such condition, the optimal performance can be attained by the 2-order AR estimator. It is illustrated in the simulation that, compared with the data from traditional methods, the blood flow parameters are estimated with smaller deviation and the lower speed flow is detected.
Blood Flow Velocity ; Equipment Design ; Humans ; Image Interpretation, Computer-Assisted ; instrumentation ; methods ; Ultrasonography, Doppler, Color ; instrumentation ; methods

In order to test the performance of wall filters, we propose a method for simulation of Hybrid Doppler testing signal, which adopts a rectangular power spectrum. In the method, the parameters of clutter, blood flow and system noise can be adjusted with flexibility. The problem about choosing model parameters is discussed as an emphasis. Several reasonable and typical parameter combination patterns are presented. Furthermore, an example is given to explain the process of choosing the parameters and testing the wall filter performance.
Blood Flow Velocity ; physiology ; Computer Simulation ; Humans ; Rheology ; instrumentation ; methods ; Signal Processing, Computer-Assisted ; Ultrasonography, Doppler, Color ; instrumentation ; methods

OBJECTIVETo study the value of contrast-enhanced ultrasound with high-frequency linear-array transducer in the diagnosis of carotid stenosis.

METHODSThe carotid arteries of 31 patients was examined with color Doppler ultrasound (CDU), harmonic contrast ultrasound (HCU) and digital subtractive angiography (DSA), respectively. The result of DSA was used as the golden standard for evaluating the accuracy, sensitivity and specificity of CDU and HCU in the diagnosis of carotid stenosis.

RESULTSSatisfactory images of 62 carotid arteries were obtained from the patients using HCU with high-frequency linear-array transducer. After intravenous injection of contrast agent, densely dotted hyperechogenic signals were found in the vascular lumen, with stronger intensity than that of the vascular walls. The filling defect areas in the lumen indicated vascular stenosis. Thirty carotid stenoses were detected by DSA, and 25 by CDU. The accuracy, sensitivity and specificity of CDU was 83.3%, 82.0% and 84.9%, respectively. HCU identified 29 carotid stenoses with accuracy, sensitivity and specificity of 96.7%, 96.7% and 97.0%, respectively, significantly higher than those of CDU (P<0.05).

CONCLUSIONHCU with high frequency linear-array transducer has better the accuracy than CDU and may serve as a good alternative for diagnosis of carotid stenosis.

Aged ; Angiography, Digital Subtraction ; Carotid Arteries ; diagnostic imaging ; Carotid Stenosis ; diagnosis ; Female ; Humans ; Image Enhancement ; Male ; Middle Aged ; Transducers ; Ultrasonography, Doppler, Color ; instrumentation ; methods

INTRODUCTIONThe purpose of this case series was to determine the sonographic features of neonatal ovarian torsion.

MATERIALS AND METHODSSeven surgically proven cases of neonatal ovarian cysts were included in this retrospective study. The patients were divided into 2 groups, torsion and non-torsion. These 7 patients were evaluated for the clinical presentation, sonographic features, surgical and pathological findings. The findings on follow-up sonography after surgery were also noted.

RESULTSThe sonographic appearance was variable. Of the 4 cases with torsion, 2 lesions had internal echoes with 'fi sh-net appearance'. The other 2 lesions were predominantly cystic on the sonography with internal echoes and echogenic nodule. A calcific focus was present in 1 of these echogenic nodules. One of the cysts had fluid-fluid level. In the non-torsion group, only 1 lesion had mixed echogenic appearance. The other 2 lesions were cystic with low level internal echoes in 1 of the cysts. The surgical procedure performed in the torsion group was salpingo-oophorectomy in 2 patients and oophorectomy in 1 patient. In 1 patient, cystectomy was attempted without success. In the non-torsion group, only cystectomy was performed with preservation of normal ovaries, which was confirmed on follow-up sonography.

CONCLUSIONThe sonographic features of cysts with 'fish-net appearance', fluid-debris level and cysts with echogenic nodule favour torsion. The former sign has so far not been described as a sonographic predictor for neonatal ovarian torsion.

Female ; Humans ; Infant, Newborn ; Ovarian Cysts ; diagnostic imaging ; pathology ; surgery ; Ovary ; diagnostic imaging ; pathology ; Postoperative Period ; Retrospective Studies ; Torsion Abnormality ; diagnostic imaging ; pathology ; surgery ; Ultrasonography, Doppler ; instrumentation