Convex Array Probe Research Articles

Convex array vector velocity imaging using transverse oscillation and its optimization.

A method for obtaining vector flow images using the transverse oscillation (TO) approach on a convex array is presented. The paper presents optimization schemes for TO fields and evaluates their performance using simulations and measurements with an experimental scanner. A 3-MHz 192-element convex array probe (pitch 0.33 mm) is used in both simulations and measurements. A parabolic velocity profile is simulated at a beam-to-flow angle of 90°. The optimization routine changes the lateral oscillation period λ࠭ as a function of depth to yield the best possible estimates based on the energy ratio between positive and negative spatial frequencies in the ultrasound field. The energy ratio is reduced from -17.1 dB to -22.1 dB. Parabolic profiles are estimated on simulated data using 16 emissions. The optimization gives a reduction in standard deviation from 8.81% to 7.4% for 16 emissions, with a reduction in lateral velocity bias from -15.93% to 0.78% at 90° (transverse flow) at a depth of 40 mm. Measurements have been performed using the experimental ultrasound scanner and a convex array transducer. A bias of -0.93% was obtained at 87° for a parabolic velocity profile along with a standard deviation of 6.37%. The livers of two healthy volunteers were scanned using the experimental setup. The in vivo images demonstrate that the method yields realistic estimates with a consistent angle and mean velocity across three heart cycles.

Safety Assessment of Advanced Imaging Sequences I: Measurements.

A method for rapid measurement of intensities (I(spta)), mechanical index (MI), and probe surface temperature for any ultrasound scanning sequence is presented. It uses the scanner's sampling capability to give an accurate measurement of the whole imaging sequence for all emissions to yield the true distributions. The method is several orders of magnitude faster than approaches using an oscilloscope, and it also facilitates validating the emitted pressure field and the scanner's emission sequence software. It has been implemented using the experimental synthetic aperture real-time ultrasound system (SARUS) scanner and the Onda AIMS III intensity measurement system (Onda Corporation, Sunnyvale, CA, USA). Four different sequences have been measured: a fixed focus emission, a duplex sequence containing B-mode and flow emissions, a vector flow sequence with B-mode and flow emissions in 17 directions, and finally a SA duplex flow sequence. A BK8820e (BK Medical, Herlev, Denmark) convex array probe is used for the first three sequences and a BK8670 linear array probe for the SA sequence. The method is shown to give the same intensity values within 0.24% of the AIMS III Soniq 5.0 (Onda Corporation, Sunnyvale, CA, USA) commercial intensity measurement program. The approach can measure and store data for a full imaging sequence in 3.8-8.2 s per spatial position. Based on I(spta), MI, and probe surface temperature, the method gives the ability to determine whether a sequence is within U.S. FDA limits, or alternatively indicate how to scale it to be within limits.

Value of linear array ultrasonic with high-frequency in the diagnosis of renal artery stenosis

Objective To evaluate the value of linear array ultrasonic with high-frequency in the diagnosis of renal artery stenosis(RAS). Methods 1 828 patients who were doubted with RAS were studied. All of them were checked by ultrasonic with convex array probe and linear array probe. Results The sensitivity, specificity, false positive rate, false negative rate of convex array probe were 8.20%,97.10%,2.90%,21.80%. The sensitivity, specificity, false positive rate, false negative rate of linear array probe were 91.13%, 99.80%, 0.20%, 8.87%. Conclusion Linear array with high- frequency can keep the measurement angle less than 60°, and can show the plaque, nature of the plaque and narrow rate of renal artery. It may be more helpful in the diagnosis of RAS. Key words: Ultrasonography; Renal Artery Obstruction

Doppler ultrasound study of portal hemodynamics in patients with Gaucher disease

Gaucher disease is a lysosomal storage disorder caused by a deficiency of the enzyme glucocerebrosidase and characterized by the presence of pathological macrophages laden with glucosylceramide. Hepatosplenomegaly is a common manifestation of Gaucher disease, but symptomatic portal hypertension is rarely seen. The study included 20 untreated adult patients with Gaucher disease (non-neuronopathic type 1) diagnosed with the presence of Gaucher cells in the bone marrow, and 20 healthy subjects as controls. The examination of patients included color Doppler ultrasonography (pulsed Doppler mode), resistive index (RI) and Doppler perfusion index (DPI) using a Toshiba Xario ultrasound machine and a convex array probe PVT-375AX (1.9-6 MHz) with the objective of analyzing portal hemodynamics. Results showed that all patients had enlarged liver and spleen, and their average sizes were significantly larger than those in the healthy controls (liver: 17.04 vs.14.02 cm; spleen: 22.2 vs. 10.74 cm). DPI values were significantly different between patients and controls (0.15 vs. 0.21). Considering DPI <0.15 indicates arterial liver hypoperfusion and hypoxia, it can be concluded that a number of patients had a problem with liver oxygenation, which may be linked to the high angiotensin-converting enzyme (ACE) levels obtained in the patients (339.42 U/L), 10 times greater than in control subjects. Since ACE is a potent vasoconstrictor produced by spleen macrophages in Gaucher disease, we can suppose that elevated ACE is associated with effects on the blood vessels of the liver and spleen.

Transverse spectral velocity estimation.

A transverse oscillation (TO)-based method for calculating the velocity spectrum for fully transverse flow is described. Current methods yield the mean velocity at one position, whereas the new method reveals the transverse velocity spectrum as a function of time at one spatial location. A convex array probe is used along with two different estimators based on the correlation of the received signal. They can estimate the velocity spectrum as a function of time as for ordinary spectrograms, but they also work at a beam-to-flow angle of 90°. The approach is validated using simulations of pulsatile flow using the Womersly-Evans flow model. The relative bias of the mean estimated frequency is 13.6% and the mean relative standard deviation is 14.3% at 90°, where a traditional estimator yields zero velocity. Measurements have been conducted with an experimental scanner and a convex array transducer. A pump generated artificial femoral and carotid artery flow in the phantom. The estimated spectra degrade when the angle is different from 90°, but are usable down to 60° to 70°. Below this angle the traditional spectrum is best and should be used. The conventional approach can automatically be corrected for angles from 0° to 70° to give fully quantitative velocity spectra without operator intervention.

Application of Real-Time Tissue Elastography with a Low Frequency Convex Array Probe: A Noninvasive Approach to Differential Diagnosis of Liver Tumors

To evaluate diagnostic performance of real-time tissue elastography (RTE) with a low frequency convex array probe for distinguishing benign from malignant hepatic tumors through trans-abdominal examination, elasticity images of 210 liver tumors were obtained by EUB-7500 (Hitachi Medical Systems and 3.5 MHz probe) and eventually 121 liver tumors were analyzed in the study. Elasticity images were classified into four types, from type a to d. Regarding type a or b as benign tumors and type c or d as malignant ones, sensitivity, specificity, and accuracy were calculated and the consistency between the findings of RTE and the pathohistological diagnosis was evaluated. The sensitivity, specificity, and accuracy were separately 97.2%, 88.0%, and 93.4% (P < 0.001). Moreover, there was a good consistency between the findings of RTE and the pathological diagnosis (kappa value 0.86). Among elasticity images of all the malignant tumors, the hepatocellular carcinomas (HCCs) mainly appeared in type c, and liver metastatic cancers in type d. Thus, RTE utilized as a novel noninvasive imaging examination method enables us to distinguish benign from malignant liver tumors. Moreover, it provides certain information for the differential diagnosis between HCCs and liver metastatic cancers.

A novel noninvasive assessment of hepatic venous pressure gradient and portal pressure computed from computed tomography angiography.

Cirrhosis is a severe and common digestive disease worldwide and is associated with a poor outcome. Portal hypertension (PHT) is a frequently encountered complication in cirrhotic patients [1–3]. Therefore, evaluation of portal pressure (PP) is urgently needed for the grading and staging of PHT. Direct measurement of PP is rarely performed due to significant invasiveness and potential complications. Hepatic venous pressure gradient (HVPG) is currently treated as the “gold standard” [1–4]. However, the invasiveness and technical difficulty greatly restrict its repeatable application. An index computed from computed tomography angiography (CTA) has recently demonstrated its diagnostic value compared with the “gold standard” [5, 6]. For instance, fractional flow reserve from coronary CTA showed good performance in the diagnosis of functional coronary stenosis in a multicenter randomized clinical controlled trial on 159 vessels in 103 patients [6]. On the basis of our previous study of noninvasive measurement of coronary stenosis by fractional flow reserve [7], this study, for the first time, introduces a novel noninvasive assessment of HVPG (HVPGni) and PP (PPni) computed from three dimensional (3D) hepatic portal venous models reconstructed from CTA to diagnose the severity of PHT in cirrhotic patients. The patient enrolled in the pilot study was a 50-year-old man who showed visible clinical manifestations of PHT, such as ascites and splenomegaly, and was diagnosed with cirrhosis in the decompensated stage. Approval was obtained from the ethical committees of Tongji Hospital and the participant gave written informed consent in advance. The CTA was performed with multi-detector CT scanners (GE Light-Speed Ultra, 120 kV, 220 mA). Original images were spilt into thin layers and exported into imaging control software MIMICS10.0. 3D hepatic portal venous models were reconstructed from surrounding tissues by different CT values, which were then meshed with 3D Flotran elements in the software ANSYS11.0. Given boundary conditions including average velocity of hepatic venous and portal venous flow were measured by color Doppler ultrasound (CDUS) (Philips iU22 x MATRIX Ultrasound System, convex array probe C5-2). Afterwards, finite element analysis and computational fluid dynamics were applied to compute the pressure distribution in the hepatic portal vein in vitro. Clinical data of the decompensated cirrhotic patient were calculated to test the feasibility and accuracy of the novel noninvasive assessment with the clinical diagnosis, CTA and CDUS as reference standards. The CTA images showed that the diameter of the portal vein was 1.6 cm while the normal diameter is ≤ 1.3 cm [2, 3]. Besides, the average velocity of portal venous flow was 12.5 cm/s, which was obviously slower than 22.62 cm/s in normal patients [1, 3, 4] and indicated severe PHT. According to the calculation by the novel assessment, HVPGni and PPni were computed as 65.2 Pa (Figure 1) and 3535.0 Pa (Figure 2), which generally corresponded to the diagnosis of PHT. Furthermore, the pressure and velocity distribution of different sections could be simultaneously obtained. Figure 1 Noninvasive assessment of hepatic ve- 702.835 1493.68 2284.52 3075.36 3866.2 nous pressure gradient in decompensated cirrhosis. Hepatic venous pressure gradient was calculated in vitro with the value of 65.2 Pa Figure 2 Noninvasive assessment of portal pressure in decompensated cirrhosis. Portal pressure was quantified in vitro as 3535.0 Pa and was generally consistent with the clinical diagnosis of portal hypertension The PHT is known as a frequent complication of cirrhosis worldwide which significantly reduces the patient's quality of life. The HVPG is currently considered as the “gold standard” to identify PHT. However, shortcomings, such as invasiveness and technical difficulty, limit its diagnostic worth greatly. In the pilot study, finite element analysis and computational fluid dynamics over the 3D hepatic portal venous model were applied, which potentially developed a novel noninvasive assessment of HVPGni and PPni to evaluate the severity of PHT. Besides, the novel assessment was successfully applied and the diagnostic performance of HVPGni and PPni was overall consistent with the clinical diagnosis, CTA and CDUS. This study introduces, for the first time, a novel noninvasive assessment of HVPGni and PPni computed from hepatic portal venous models, which might be a potential diagnostic tool to evaluate the severity of PHT, grading of cirrhosis and choice of treatment in the future. However, large randomized clinical controlled trials evaluated by both the novel assessment and invasive “gold standard” are needed before the application from bench to bedside.

The Effect of Dead Elements on the Accuracy of Doppler Ultrasound Measurements

The objective of this study is to investigate the effect of multiple dead elements in an ultrasound probe on the accuracy of Doppler ultrasound measurements. For this work, we used a specially designed ultrasound imaging system, the Ultrasonix Sonix RP, that provides the user with the ability to disable selected elements in the probe. Using fully functional convex, linear, and phased array probes, we established a performance baseline by measuring the parameters of a laminar parabolic flow profile. These same parameters were then measured using probes with 1 to 10 disabled elements. The acquired velocity spectra from the functional probes and the probes with disabled elements were then analyzed to determine the overall Doppler power, maximum flow velocity, and average flow velocity. Color Flow Doppler images were also evaluated in a similar manner. The analysis of the Doppler spectra indicates that the overall Doppler power as well as the detected maximum and average velocities decrease with the increasing number of disabled elements. With multiple disabled elements, decreases in the detected maximum and average velocities greater than 20% were recorded. Similar results were also observed with Color Flow Doppler measurements. Our results confirmed that the degradation of the ultrasound probe through the loss of viable elements will negatively affect the quality of the Doppler-derived diagnostic information. We conclude that the results of Doppler measurements cannot be considered accurate or reliable if there are four or more contiguous dead elements in any given probe.

New Adaptive Clutter Rejection Based on Spectral Analysis for Ultrasound Color Doppler Imaging: Phantom and In Vivo Abdominal Study

Effective rejection of time-varying clutter originating from slowly moving vessels and surrounding tissues is important for depicting hemodynamics in ultrasound color Doppler imaging (CDI). In this paper, a new adaptive clutter rejection method based on spectral analysis (ACR-SA) is presented for suppressing nonstationary clutter. In ACR-SA, tissue and flow characteristics are analyzed by singular value decomposition and tissue acceleration of backscattered Doppler signals to determine an appropriate clutter filter from a set of clutter filters. To evaluate the ACR-SA method, 20 frames of complex baseband data were acquired by a commercial ultrasound system equipped with a research package (Accuvix V10, Samsung Medison, Seoul, Korea) using a 3.5-MHz convex array probe by introducing tissue movements to the flow phantom (Gammex 1425 A LE, Gammex, Middleton, WI, USA). In addition, 20 frames of in vivo abdominal data from five volunteers were captured. From the phantom experiment, the ACR-SA method provided 2.43 dB (p <; 0.001) and 1.09 dB ( ) improvements in flow signal-to-clutter ratio (SCR) compared to static (STA) and down-mixing (ACR-DM) methods. Similarly, it showed smaller values in fractional residual clutter area (FRCA) compared to the STA and ACR-DM methods (i.e., 2.3% versus 5.4% and 3.7%, respectively, ). The consistent improvements in SCR from the proposed ACR-SA method were obtained with the in vivo abdominal data (i.e., 4.97 dB and 3.39 dB over STA and ACR-DM, respectively). The ACR-SA method showed less than 1% FRCA values for all in vivo abdominal data. These results indicate that the proposed ACR-SA method can improve image quality in CDI by providing enhanced rejection of nonstationary clutter.

The Value of Small Bowel Wall Contrast Enhancement After Sulfur Hexafluoride-Filled Microbubble Injection to Differentiate Inflammatory from Fibrotic Strictures in Patients with Crohn's Disease

We analysed the value of contrast-enhanced ultrasound to differentiate inflammatory from fibrotic ileal strictures in patients with Crohn's disease (CD). Twenty-eight patients (17 male and 11 female; mean age ± SD, 48.5 ± 17.17 years) with a biopsy-proven diagnosis of CD were included. In each patient, the terminal ileal loop was scanned by a convex-array probe (2–5 MHz) before and after sulphur hexafluoride-filled microbubble injection. The digital cine-clip registered after microbubble injection during the first-pass dynamic enhancement was quantified in gray-scale levels by a dedicated software through manually drawn regions-of-interest (ROIs) encompassing the anterior bowel wall. Time-intensity curves from patients with inflammatory and fibrotic ileal strictures, fitted according to the theoretical gamma variate curve, were compared. Inflammatory vs. fibrotic ileal strictures differed in the percentage of maximal enhancement (45.86 ± 5.32 vs. 37.33 ± 16.24%; p < 0.05) and area under the enhancement curve (1168.25 ± 437.65 vs. 570.47 ± 323.08; p < 0.05), whereas the difference in time to peak enhancement was found not significant (9.25 ± 4.21 vs. 12.01 ± 7.34 s; p > 0.05). The quantitative analysis of small bowel wall contrast enhancement after microbubble contrast agent injection may differentiate inflammatory from fibrotic ileal strictures in patients with CD.

Calibration procedure for performance evaluation of clinical Pulsed Doppler Systems

This paper describes the analysis of an experimental setup for the performances evaluation of Pulsed Doppler feature in clinical ultrasound scanners. The equipment basically consist on a commercial flow phantom made by a straight tube having a known and constant cross sectional area in which a blood mimicking fluid is forced to flow at laminar conditions. Given the accuracy declared by the manufacturer (±0.7cm/s), unsatisfactory for low flow rates, we calibrated the phantom using the gravimetric method. From the digitized images of the Pulsed Doppler spectra over time, the mean velocities have been computed with the software package developed by the authors. Moreover, to test the calibration procedure in effective conditions, we carried out performance test on five different ultrasound platforms, equipped with phased array and convex array probes with a nominal mean velocity of the blood mimicking fluid ranging from 1.1cm/s to 12.7cm/s. The pooled data showed an overestimation of the mean velocity, from over 200% down to about 50%, depending on nominal flow rate and ultrasound equipment. The same data, corrected via the calibration curve, showed a sensible recovery of the estimated accuracy of the tested platforms at low flow rates (<3cm/s).

Renal volume assessment with 3D ultrasound

This study was undertaken to determine the accuracy of 3D ultrasound (US) in assessing renal volume, with multislice computed tomography (MSCT) considered as the gold standard. Forty-nine patients (30 men, 19 women; age range 30-82 years) underwent abdominal contrast-enhanced MSCT and 3D-US performed with a 3.5-MHz 3D/4D convex-array probe. The results of the two modalities were compared with the Wilcoxon test. Variability between the two measurements was determined with the Bland-Altman method and reported in terms of bias and coefficient of repeatability (CoR). Mean values obtained were 210 ml with MSCT and 192 ml with 3D-US (p<0.001). Analysis of variability per patient between MSCT and 3D-US showed a bias of 19 ml, a CoR of 47 ml and an accuracy of 78%, with an average 3D-US underestimation of 19 ml (9%). Analysis of variability per kidney showed a bias of 9 ml, a CoR of 34 ml and an accuracy of 80%. Three-dimensional US is a valuable technique for monitoring renal volume, whereas MSCT may be reserved for assessing renal anatomy and relationships with neighbouring organs.

Blood Flow Measurement by the Counter-Crossed Beam Contrast Echo Method

We propose a new contrast-echo method using the counter-crossed beams of two ultrasonic frequencies for ultrasound diagnosis of cancer and call it the counter-cross beam contrast echo (C-CBCE) method. In this C-CBCE method, the sum- or difference-frequency components generated by the nonlinear vibration of microbubbles driven by dual-frequency ultrasound are used for measuring flow velocity. The C-CBCE method has the potential to measure low blood flow velocities, since the echo from the blood flow is efficiently separated from the echo from the biological soft tissues using the sum- or difference-frequency component. Sonazoid is used as microbubbles, and the sum frequency is used in the experiments. We prototyped the measurement system, which consists of commercially available ultrasound diagnostic equipment with a convex array probe and another ultrasonic probe, in order to determine the feasibility of the C-CBCE method in clinical diagnosis. In this study, we employ the C-CBCE method to measure the flow velocity of microbubbles in a channel using the sum-frequency component generated by the nonlinear vibration of microbubbles. We demonstrate theoretically the relationship between the Doppler-shift frequency of the sum-frequency component and the flow velocity in a channel. In order to confirm the theory on which this method is based, we then determine flow velocities on the basis of the sum-frequency component, fundamental component, and second-harmonic component.

頚動脈狭窄における収縮期加速時間の有用性

The aim of this study was to investigate the usefulness of acceleration time (AcT) determined by sonography for evaluation of severe stenosis in the internal carotid artery (iCA). We evaluated 127 ICAs and common carotid arteries (CCAs). Linear- and convex-array probes were used for sonographic assessment, and the peak systolic flow velocity (PSV) at the carotid bulb was evaluated by the pulsed Doppler method. The linear-array probe was set in the CCA 2cm above the carotid sinus, and the convex-array probe was set in the ICA 3cm above its origin to measure the Doppler waveform. The Act ratio was calculated as ICA/AcT of the ipsilateral CCA and correlated with the PSV. Simple regression analysis and the receiver operating characteristic curve were used to examine the relationship between the AcT ratio and PSV. There was a significant relationship between the PSV and AcT ratio. Based on the receiver operating characteristic curve, the sensitivity and specificity of the AcT ratio using a cutoff level of 2.0 were 90.0% and 96.6%, respectively, for diagnosis of a PSV exceeding 200cm/s. These results suggest that an AcT ratio of 2.0 reflects a degree of stenosis exceeding 70%.

Contrast-enhanced ultrasound in diagnosing liver malignancy

The use of contrast enhancers has widened the possibilities of sonographic imaging, and allows the differentiation of characteristic enhancement patterns leading to diagnosis in focal liver lesions. The aim of our study was to evaluate contrast ultrasound signs in diagnosing malignant liver lesions. 86 patients with 100 solid liver lesions were enrolled. A baseline gray-scale sonogram was obtained with a multifrequency 4 C convex array probe, followed by contrast-enhanced sonography with a low mechanical index (<0.2) over 300 seconds. Final diagnosis was confirmed by histology or in case of haemangioma by CT/NMR and quantitative contrast harmonic imaging (CHI) with perfusion analysis (contrast). 55 malignant (6 HCC, 46 secondary malignant lesions - 3 of them lymphoma, 3 cholangiocarcinoma), and 45 benign lesions (8 FNH, 1 von Meyenburg complex, 1 granuloma, 3 adenoma, 21 hemangioma, 2 focal fat storage imbalances, 7 abscesses, one scar, and in one case normal liver) were found. 51/55 malignant (all but one filia and three HCC), but also 17/45 benign lesions showed hypoperfusion in the late phase. The ultrasound pattern in the arterial phase differed in malignant lesions: 22 lesions were initially hypervascular, 20 had rim enhancement and in 13 lesions there was a non-specific vascularisation. In all but one malignant lesion a diminishing of contrast agent in the late phase compared to the arterial phase with respect to the surrounding liver tissue was observed. Only three benign lesions with this later sign were falsely diagnosed as malignant: one adenoma, one epitheloid granuloma, and a scar. Quantitative perfusion pattern was analyzed exemplary. Diminishing of contrast agent in the late phase compared to the arterial phase with respect to the surrounding liver tissue as a sign for malignancy had a positive predictive value of 95%, a sensitivity of 98%, a negative predictive value of 98%, and a specificity of 93%. Diminishing of contrast agent in the late phase compared to the arterial phase with respect to the surrounding liver tissue is a helpful sign in contrast enhanced ultrasound to diagnose malignancies.

Ultrasonographic study of gallbladder motility in patients with diabetes mellitus and autonomic neuropathy

Aim: Ultrasonographic assessment of gallbladder motility in patients with diabetes mellitus and autonomic neuropathy, having treatment with gabapentinum. Patients and methods: 30 patients with type II diabetes mellitus with various symptoms of autonomic neuropathy undertook this clinical study consisting of treatment with gabapentinum with initial dose of 3×300mg/day, with increasing doses till 3600mg/day for 6 months. They've got no previous gastric surgery, vagal denervation, or gallstones, sex ratio was:M/W=19/11, mean age=65.32±9.78 years, body mass index=33.44±5.51kg/m2. They also didn't receive associated treatment with prokinetic agents. We assess the gallbladder motility response related to this medication. Patients were examined by transabdominal ultrasonography with a 3.5MHz convex array probe, before and after the treatment. We calculated the gallbladder initial and residual volume with ellipsoid method and gallbladder ejection fraction. in fasting state and 30 minutes after a cholecystokinetic meal. An ejection fraction bellow 60% was considered pathological. Results: Before therapy the group of diabetic patients with neuropathy had a mean gallbladder ejection fraction=31.10%±3.98, showing a constant low rate of gallbladder emptying. After treatment the mean gallbladder ejection fraction was 49.59%±5.11, representing an elevation of gallbladder ejection fraction with 18.49%±1.13%, and an improving of gallbladder motility. Conclusions: Ultrasonography examination provided us with data concerning gallbladder motility disorders, represented by delaying of gallbladder emptying and decreasing the gallbladder ejection fraction. According to our results after treatment with gabapentinum diabetic patients showed a slightly improvement of gallbladder motility with promising clinical outcome regarding the dyspeptic complains and other related risk factors.

2370: Assessment of the vascularity of small pancreatic carcinomas by intraoperative contrast US

Objectives: Evaluation of tumor vascularity by contrast-enhanced US is not necessarily satisfactory in the case of small pancreatic carcinomas. In this study, we used intraoperative contrast US to assess the vascularity of small pancreatic carcinomas less than 2 cm in diameter.Methods: Six patients with small invasive carcinomas of the pancreas were evaluated. During surgery, a convex array probe was placed on the tumor surface. Observation was performed using an Aplio device (Toshiba Co., Ltd.) with Levovist.Results: Tumor vascularity could be classified into three patterns. (1) Diffuse enhancement with spotty and/or linear vessel signals throughout the lesion. (2) Peripheral spotty enhancement. (3) No enhancement. In the tumors with no enhancement, histological specimens revealed massive tumor cell invasion with dense fibrosis. In the tumors with diffuse enhancement, invasion was less prominent and some pancreatic parenchyma and vessels remained between the tumor cell nests.Conclusions: When the carcinoma is small and invasion is less prominent, both pancreatic parenchyma and vessels that remain inside the tumor border are enhanced. As tumor growth progresses, enhancement decreases from the center outward. We conclude that, even in patients with small pancreatic carcinomas, tumor vascularity may not only demonstrate the extent of the lesion but also indicate the prognosis. Objectives: Evaluation of tumor vascularity by contrast-enhanced US is not necessarily satisfactory in the case of small pancreatic carcinomas. In this study, we used intraoperative contrast US to assess the vascularity of small pancreatic carcinomas less than 2 cm in diameter. Methods: Six patients with small invasive carcinomas of the pancreas were evaluated. During surgery, a convex array probe was placed on the tumor surface. Observation was performed using an Aplio device (Toshiba Co., Ltd.) with Levovist. Results: Tumor vascularity could be classified into three patterns. (1) Diffuse enhancement with spotty and/or linear vessel signals throughout the lesion. (2) Peripheral spotty enhancement. (3) No enhancement. In the tumors with no enhancement, histological specimens revealed massive tumor cell invasion with dense fibrosis. In the tumors with diffuse enhancement, invasion was less prominent and some pancreatic parenchyma and vessels remained between the tumor cell nests. Conclusions: When the carcinoma is small and invasion is less prominent, both pancreatic parenchyma and vessels that remain inside the tumor border are enhanced. As tumor growth progresses, enhancement decreases from the center outward. We conclude that, even in patients with small pancreatic carcinomas, tumor vascularity may not only demonstrate the extent of the lesion but also indicate the prognosis.

Sonographic assessment of changes in thickness of different abdominal fat layers in response to diet in obese women.

We evaluated the potential application of sonography to monitor alterations in abdominal fat thickness in obese women before and after dieting. This study included 40 obese women (mean age, 42.2 +/- 9.4 years; mean body mass index [BMI], 36.0 +/- 5.9 kg/m2) who underwent a 3-month low-calorie diet. Height, weight, waist circumference (WC), and hip circumference (HC) were measured. BMI and waist-to-hip ratio (WHR) were calculated. Abdominal subcutaneous (S) and intra-abdominal preperitoneal (P) fat were measured at their maximum (max) and minimum (min) thickness sites using a 7.5-MHz linear-array probe. Intra-abdominal visceral (V) fat was measured using a 3.5-MHz convex-array probe. Measurements were taken before and after caloric restriction. The mean weight was reduced from 88.6 +/- 17.1 kg to 83.0 +/- 15.9 kg (p < 0.0001). The mean changes in S(min) (r = 0.376, p = 0.017), S(max) (r = 0.508, (p = 0.001), P(min) (r = 0.439, p = 0.005), and V (r = 0.365, p = 0.022) fat thicknesses were positively correlated with change in weight; the change in P(max) fat thickness showed the best and most significant correlation (r = 0.591, p < 0.0001). BMI (r = 0.969, p < 0.0001), WC (r = 0.510, p = 0.001), and HC (r = 0.422, p = 0.007) changes were also positively correlated with weight change, but the WHR change (r = 0.019, p > 0.05) was not. All the abdominal fat layers, particularly the intra-abdominal P fat, will decrease in response to loss of body fat by dieting. Sonography seems to be useful in monitoring small variations in the thicknesses of abdominal S and intra-abdominal P and V fat.

Correlation of abdominal fat accumulation and liver steatosis: importance of ultrasonographic and anthropometric measurements

Purpose: This study has two objectives: (1) using ultrasound (US) as a tool for measuring subcutaneous (S) and intra-abdominal; preperitoneal (P) and visceral (V) fat thickness. (2) Assessing the relationship between selected anthropometrical variables and US-measured S, P and V fat also evaluating the contribution of abdominal fat accumulation in development of liver steatosis. Methods and materials: Sixty-eight obese patients (aged 43.9±9.3 years) and 40 non-obese subjects (aged 34.03±9.0 years) were recruited to this study. Height, weight (W), waist (WC) and hip circumferences were measured. Body mass index (BMI) and waist to hip ratio (WHR) were calculated. A linear-array probe (7.5 MHz) was used to measure S and P. A convex-array probe (3.5 MHz) was used for measuring V and assessing liver fatty infiltration. Results: In 45 (66%) patients, there were diffuse liver fatty changes. Liver steatosis showed significant correlation with V ( r=0.57), P ( r=0.38) and S ( r=0.37). It also correlated with W ( r=0.52), BMI ( r=0.6), WC ( r=0.45) ( P<0.0001). V positively correlated with BMI ( r=0.62), W ( r=0.55), WC ( r=0.52) and WHR ( r=0.33). P correlated with WC ( r=0.29), WHR ( r=0.36) and W ( r=0.34), but not with BMI, height and age. A significant correlation was found between S and BMI ( r=0.73), W ( r=0.65), and WC ( r=0.57) ( P<0.0001). Conclusion: Obese patients showed thicker S, P, and V. Liver steatosis correlates significantly with both anthropometrical data; BMI, WHR, WC, and W, and with abdominal V, P, and S fat. V fat can be used as a good predictor for the possibility of different metabolic disorders and liver disturbances as steastosis.

Laparoscopic ultrasonography in the management of ectopic pregnancy: is there a possible role?

Objective Ectopic pregnancy is a potentially serious condition. The standard methods of diagnosis include estimation of the beta subunit of human chorionic gonadotrophin (β‐hCG), transvaginal ultrasonography (TVUS), and laparoscopy. Diagnostic laparoscopy yields up to 2% false‐positive and 4.5% false‐negative results with potentially serious consequences. Two cases where the technique of laparoscopic ultrasonography was used in the diagnosis of unruptured ectopic pregnancies are described. Subjects Laparoscopic ultrasonography was used in cases of suspected ectopic pregnancy to confirm the diagnosis. A 60° convex array probe with multifrequency (5, 6.5 and 7.5 MHz) and a radius of curvature of 20 mm was used. The probe was introduced through a 10‐mm port. Results The laparoscopic ultrasound probe could clearly detect early ectopic pregnancy. This technique is also superior to transvaginal ultrasonography in identifying an early intrauterine pregnancy. Conclusion Our results suggest that laparoscopic ultrasonography may assist in the diagnosis of ectopic pregnancy when the findings at laparoscopy are uncertain.