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Sample records for contrast-enhanced power doppler

  1. Improved Contrast-Enhanced Power Doppler Using a Coherence-Based Estimator.

    PubMed

    Tremblay-Darveau, Charles; Bar-Zion, Avinoam; Williams, Ross; Sheeran, Paul S; Milot, Laurent; Loupas, Thanasis; Adam, Dan; Bruce, Matthew; Burns, Peter N

    2017-09-01

    While plane-wave imaging can improve the performance of power Doppler by enabling much longer ensembles than systems using focused beams, the long-ensemble averaging of the zero-lag autocorrelation R(0) estimates does not directly decrease the mean noise level, but only decreases its variance. Spatial variation of the noise due to the time-gain compensation and the received beamforming aperture ultimately limits sensitivity. In this paper, we demonstrate that the performance of power Doppler imaging can be improved by leveraging the higher lags of the autocorrelation [e.g., R(1), R(2),…] instead of the signal power (R(0)). As noise is completely uncorrelated from pulse-to-pulse while the flow signal remains correlated significantly longer, weak signals just above the noise floor can be made visible through the reduction of the noise floor. Finally, as coherence decreases proportionally with respect to velocity, we demonstrate how signal coherence can be targeted to separate flows of different velocities. For instance, we show how long-time-range coherence of microbubble contrast-enhanced flow specifically isolates slow capillary perfusion (as opposed to conduit flow).

  2. Echo contrast-enhanced three-dimensional power Doppler of intracranial arteries.

    PubMed

    Postert, T; Braun, B; Pfundtner, N; Sprengelmeyer, R; Meves, S; Przuntek, H; Büttner, T

    1998-09-01

    The purpose of this study was to evaluate the potential of contrast-enhanced three-dimensional (3-D) power Doppler (CE3DPD) in the assessment of intracranial vascular structures, and to compare the results with unenhanced 3-D power Doppler (3DPD) and magnetic resonance angiography (MRA) findings. We insonated 25 patients without cerebrovascular diseases through the temporal bone window using 3DPD and CE3DPD; for comparison, 13 patients underwent MRA. Identification rates of vascular segments and of small branches of intracranial vessels were evaluated by two independent investigators blinded to MRA results. In 21 patients with adequate insonation conditions, CE3DPD significantly improved identification rates compared to 3DPD for the complete visualization of the P1 segment (80.9 vs. 19.0%, p < 0.005, P2 segment (80.9 vs. 42.8%, p < 0.05 and A1 segment (85.7 vs. 38.1%, p < 0.005). Furthermore, CE3DPD depicted, in significantly more examinations, branches of the middle (MCA) and posterior cerebral artery (PCA). Interobserver agreement was higher than 95% for the main intracranial segments and branches of the MCA, but relatively low (80.1-85.7%) for branches of the PCA. In comparison to CE3DPD, MRA identified only parieto-occipital branches of the PCA, temporal branches of the MCA, frontal branches of the anterior cerebral artery and the MCA bifurcation more frequently and accurately. In 4 patients with inadequate acoustic temporal bone windows, the application of a galactose-based microbubble suspension allowed clear 3-D visualization of almost all major intracranial vascular segments and some branches of the large arteries. In conclusion, CE3DPD is a more sensitive ultrasonic tool compared to unenhanced 3-D reconstructions. It makes 3-D ultrasound imaging of the basal cerebral circulation easier to perform and interpret, by providing an improved spatially oriented display of image position. As such, this method may increase operator diagnostic confidence level under

  3. Contrast-enhanced power Doppler US in the diagnosis of renal pseudotumors.

    PubMed

    Ascenti, G; Zimbaro, G; Mazziotti, S; Gaeta, M; Lamberto, S; Scribano, E

    2001-01-01

    The term "pseudotumor" is used to refer to several anatomic variants that can simulate a renal mass, the most frequent of which are hypertrophied column of Bertin, persistence of fetal lobation, and the dromedary or splenic hump. We describe the findings of power Doppler US after the ultrasound contrast agent (Levovist, Schering, Berlin, Germany) administration in 4 patients with a renal focal lesion in whom gray-scale and baseline power Doppler US was not able to certainly differentiate pseudotumor from neoplasm.

  4. Hepatocellular Carcinoma Treated with Chemoembolization: Assessment with Contrast-Enhanced Doppler Ultrasonography

    SciTech Connect

    Catalano, Orlando; Esposito, Maria; Lobianco, Roberto; Cusati, Bianca; Altei, Francesco; Siani, Alfredo

    1999-11-15

    Purpose: To report our preliminary experience concerning the use of Doppler ultrasonography (DUS) techniques after intravenous injection of the galactose-based contrast agent Levovist in the assessment of hepatocellular carcinoma (HCC) treated with transcatheter arterial chemoembolization (TACE). The sonographic findings are correlated with those obtained using iodized oil (Lipiodol) helical computed tomography (CT). Methods: For 7 months we studied 28 patients with cirrhosis and HCC (a total of 43 nodules) who had undergone TACE between 18 and 30 days previously. The lesions were investigated with color Doppler ultrasonography (CDUS) and power Doppler ultrasonography (PDUS), before and after infusion of the echo-contrast agent (300 mg/ml, maximum 1 injection for each nodule, administered at constant velocity within 60-90 sec), and with helical Lipiodol-CT (0-7 days after DUS). In the retrospective analysis, special attention was given to the Doppler signals related to pulsatile intra- and perinodular flow and to the detection of new vessels after contrast agent injection. The signal intensity was graded as 0 (absent), 1 (low), 2 (medium), or 3 (high), while its distribution was classified as peripheral, central, or diffuse. Oily agent retention on CT scans was assessed as 0 (absent), I (<10%), II (<50%), III (>50%), or IV (homogeneous). These scores were awarded separately, without knowledge of the other judgments. Results: An hepatic global echo-enhancing effect was identified in all cases and always lasted long enough to allow an accurate analysis of all parenchymal lesions (at least 8 min). The signal scores could be evaluated in 39 of 43 HCCs, as follows: basal CDUS: grade 0 in 17 lesions, grade 1 in 16, grade 2 in 6; contrast-enhanced CDUS: grade 0 in 12 lesions, grade 1 in 10, grade 2 in 14, grade 3 in 3; basal PDUS: grade 0 in 15 lesions, grade 1 in 13, grade 2 in 9, grade 3 in 2; contrast-enhanced PDUS: grade 0 in 11 lesions, grade 1 in 9, grade 2 in 15

  5. Assessment of changes in vascularity and blood volume in canine sarcomas and squamous cell carcinomas during fractionated radiation therapy using quantified contrast-enhanced power Doppler ultrasonography: a preliminary study.

    PubMed

    Ohlerth, Stefanie; Bley, Carla Rohrer; Laluhová, Dagmar; Roos, Malgorzata; Kaser-Hotz, Barbara

    2010-10-01

    Radiation therapy does not only target tumour cells but also affects tumour vascularity. In the present study, changes in tumour vascularity and blood volume were investigated in five grade 1 oral fibrosarcomas, eight other sarcomas (non-oral soft tissue and bone sarcomas) and 12 squamous cell carcinomas in dogs during fractionated radiation therapy (total dose, 45-56 Gy). Contrast-enhanced power Doppler ultrasound was performed before fraction 1, 3, 6, 8, 10, 12, 14 and 15 or 16 (sarcomas) or 17 (squamous cell carcinomas). Prior to treatment, median vascularity and blood volume were significantly higher in squamous cell carcinomas (P=0.0005 and 0.001), whereas measurements did not differ between oral fibrosarcomas and other sarcomas (P=0.88 and 0.999). During the course of radiation therapy, only small, non-significant changes in vascularity and blood volume were observed in all three tumour histology groups (P=0.08 and P=0.213), whereas median tumour volume significantly decreased until the end of treatment (P=0.04 for fibrosarcomas and other sarcomas, P=0.008 for squamous cell carcinomas). It appeared that there was a proportional decrease in tumour volume, vascularity and blood volume. Doppler measurements did not predict progression free interval or survival in any of the three tumour groups (P=0.06-0.86). However, the number of tumours investigated was small and therefore, the results can only be considered preliminary.

  6. Review of ultrasonography of malignant neck nodes: greyscale, Doppler, contrast enhancement and elastography

    PubMed Central

    Ying, M.; Bhatia, K.S.S.; Lee, Y.P.; Yuen, H.Y.

    2013-01-01

    Abstract Assessment of neck lymph nodes is essential in patients with head and neck cancers for predicting the patient’s prognosis and selecting the appropriate treatment. Ultrasonography is a useful imaging tool in the assessment of neck lymph nodes. Greyscale ultrasonography assesses the size, distribution, and internal architecture of lymph nodes. Doppler ultrasonography evaluates the intranodal vascular pattern and resistance of lymph nodes. Contrast-enhanced ultrasonography provides information on lymph node parenchymal perfusion. Elastography allows qualitative and quantitative assessment of lymph node stiffness. This article reviews the value of greyscale, Doppler and contrast-enhanced ultrasonography as well as elastography in the assessment of malignant nodes in the neck. PMID:24434158

  7. Concepts and trade-offs in velocity estimation with plane-wave contrast-enhanced Doppler.

    PubMed

    Tremblay-Darveau, Charles; Williams, Ross; Sheeran, Paul; Milot, Laurent; Bruce, Matthew; Burns, Peter

    2016-07-29

    While long Doppler ensembles are, in principle, beneficial for velocity estimates, short acoustic pulses must be used in microbubble contrast-enhanced Doppler to mitigate microbubble destruction. This introduces inherent trade-offs in velocity estimates with autocorrelators, which are studied here. A model of the autocorrelation function adapted to the microbubble Doppler signal, accounting for transit time, the echo frequency uncertainty and contrast-agent destruction is derived and validated in vitro. It is further demonstrated that a local measurement of the center frequency of the microbubble echo is essential in order to avoid significant bias in velocity estimates arising from the linear and nonlinear frequency-dependent scattering of microbubbles, and compensate the inherent speckle nature of the received echo frequency. For these reasons, broadband Doppler estimators (2D autocorrelator, Radon projection) are better suited than simpler narrowband estimators (1D autocorrelator, 1D Fourier transform) for contrast-enhanced flow assessment. A case study of perfusion in a VX-2 carcinoma using contrast-enhanced planewave Doppler is also shown. We demonstrate that even when considering all uncertainties associated with microbubble-related decorrelation (destruction, pulse bandwidth, transit time, flow gradient) and the need for real-time imaging, a coefficient of variation of 4% on the an axial velocity is achievable with planewave imaging.

  8. Concepts and Tradeoffs in Velocity Estimation With Plane-Wave Contrast-Enhanced Doppler.

    PubMed

    Tremblay-Darveau, Charles; Williams, Ross; Sheeran, Paul S; Milot, Laurent; Bruce, Matthew; Burns, Peter N

    2016-11-01

    While long Doppler ensembles are, in principle, beneficial for velocity estimates, short acoustic pulses must be used in microbubble contrast-enhanced (CE) Doppler to mitigate microbubble destruction. This introduces inherent tradeoffs in velocity estimates with autocorrelators, which are studied here. A model of the autocorrelation function adapted to the microbubble Doppler signal accounting for transit time, the echo frequency uncertainty, and contrast-agent destruction is derived and validated in vitro. It is further demonstrated that a local measurement of the center frequency of the microbubble echo is essential in order to avoid significant bias in velocity estimates arising from the linear and nonlinear frequency-dependent scattering of microbubbles and compensate for the inherent speckle nature of the received echo frequency. For these reasons, broadband Doppler estimators (2-D autocorrelator and Radon projection) are better suited than simpler narrow-band estimators (1-D autocorrelator and 1-D Fourier transform) for CE flow assessment. A case study of perfusion in a VX-2 carcinoma using CE plane-wave Doppler is also shown. We demonstrate that even when considering all uncertainties associated with microbubble-related decorrelation (destruction, pulse bandwidth, transit time, and flow gradient) and the need for real-time imaging, a coefficient of variation of 4% on the axial velocity is achievable with plane-wave imaging.

  9. Sonographic imaging of extra-testicular focal lesions: comparison of grey-scale, colour Doppler and contrast-enhanced ultrasound

    PubMed Central

    Rafailidis, Vasileios; Robbie, Hasti; Konstantatou, Eleni; Huang, Dean Y; Deganello, Annamaria; Sellars, Maria E; Cantisani, Vito; Isidori, Andrea M

    2016-01-01

    Extra-testicular lesions are usually benign but present with nonspecific grey-scale sonography findings. This study assesses conventional sonographic characteristics in the differentiation of extra-testicular tumoural from inflammatory lesions and whether contrast-enhanced ultrasound has a role. A retrospective database analysis was performed. All patients were examined by experienced sonographers employing standard techniques combining grey-scale, colour Doppler sonography and contrast-enhanced ultrasound. Features recorded were: clinical symptoms, size, location, echogenicity, colour Doppler sonography and contrast-enhanced ultrasound enhancement. Vascularity on colour Doppler sonography and contrast-enhanced ultrasound was graded and compared. The lesions were classified as tumoural or inflammatory. The Chi-square test was used to analyse the sonographic patterns and kappa coefficient to measure the agreement between colour Doppler sonography and contrast-enhanced ultrasound. A total of 30 lesions were reviewed (median diameter 12 mm, range 5–80 mm, median age 52 years, range 18–86 years), including 13/30 tumoural and 17/30 inflammatory lesions. Lesions were hypoechoic (n = 12), isoechoic (n = 6), hyperechoic (n = 2) or mixed (n = 10). Grey-scale characteristics of tumoural vs. inflammatory lesions differed significantly (P = 0.026). On colour Doppler sonography, lesions had no vessels (n = 16), 2–3 vessels (n = 10) and ≥4 vessels (n = 4). On contrast-enhanced ultrasound, lesions showed no vascularity (n = 17), perfusion similar to testis (n = 7) and higher (n = 6). All abscesses identified (n = 9) showed no vascularity on both colour Doppler sonography and contrast-enhanced ultrasound. There was good agreement between these techniques in evaluating vascularity (κ = 0.719) and no significant difference between colour Doppler sonography and contrast-enhanced ultrasound of tumoural vs. inflammatory

  10. Monitoring of hepatocellular carcinoma, following proton radiotherapy, with contrast-enhanced color Doppler ultrasonography.

    PubMed

    Niizawa, Gaku; Ikegami, Tadashi; Matsuzaki, Yasushi; Saida, Yukihisa; Tohno, Eriko; Kurosawa, Takashi; Saito, Yoshifumi; Chiba, Toshiya; Kita, Yasuyo; Tokuuye, Koichi; Akine, Yasuyuki; Tanaka, Naomi

    2005-03-01

    We have reported that proton radiotherapy for hepatocellular carcinoma (HCC) is a safe and effective therapeutic option. However, it is difficult to evaluate its effect in certain cases. Recently, it has been reported that the usage of contrast-enhanced color Doppler ultrasonography (CECDU) can improve diagnostic accuracy, both in terms of the presence of hepatic tumor and in the evaluation of treatment. The aim of this study was to determine the usefulness of CECDU in assessing the therapeutic response of HCC treated with proton radiotherapy. Twenty-two patients treated with the proton radiotherapy were studied. We inspected HCC lesions by CECDU, before and after the irradiation, over time. The magnitude of blood flow in the HCC was quantified on still images by CECDU. The ratio of the number of color pixels against that of the total number of pixels in the tumor area was defined as the tumor blood flow ratio (TBFR). Immediately after the proton treatment, a transient increase of blood flow in the tumor was recognized in more than half of the patients, while the TBFR was unchanged or decreased in the remaining patients. At longer periods after irradiation, the TBFR in all HCCs gradually decreased, and this reduction of TBFR was statistically significant from 9 months after irradiation. These findings are consistent with those obtained previously by computed tomography (CT) as well as magnetic resonance imaging (MRI). We propose CECDU as a useful diagnostic option for the evaluation of HCC treated with proton radiotherapy.

  11. Can Doppler or contrast-enhanced ultrasound analysis add diagnostically important information about the nature of breast lesions?

    PubMed Central

    Stanzani, Daniela; Chala, Luciano F.; de Barros, Nestor; Cerri, Giovanni G.; Chammas, Maria Cristina

    2014-01-01

    OBJECTIVES: Despite evidence suggesting that Doppler ultrasonography can help to differentiate between benign and malignant breast lesions, it is rarely applied in clinical practice. The aim of this study was to determine whether certain vascular features of breast masses observed by duplex Doppler and color Doppler ultrasonography (before and/or after microbubble contrast injection) add information to the gray-scale analysis and support the Breast Imaging-Reporting and Data System (BI-RADS) classification. METHODS: Seventy solid lesions were prospectively evaluated with gray-scale ultrasonography, color Doppler ultrasonography, and contrast-enhanced ultrasonography. The morphological analysis and lesion vascularity were correlated with the histological results. RESULTS: Percutaneous core biopsies revealed that 25/70 (17.5%) lesions were malignant, while 45 were benign. Hypervascular lesions with tortuous and central vessels, a resistive index (RI)≥0.73 before contrast injection, and an RI≥0.75 after contrast injection were significantly predictive of malignancy (p<0.001). CONCLUSION: The combination of gray-scale ultrasonography data with unenhanced or enhanced duplex Doppler and color Doppler US data can provide diagnostically useful information. These techniques can be easily implemented because Doppler devices are already present in most health centers. PMID:24519198

  12. Transmission grating stretcher for contrast enhancement of high power lasers.

    PubMed

    Tang, Yunxin; Hooker, Chris; Chekhlov, Oleg; Hawkes, Steve; Collier, John; Rajeev, P P

    2014-12-01

    We propose, for the first time, a transmission grating stretcher for high power lasers and demonstrate its superiority over conventional, reflective gold grating stretchers in terms of pulse temporal quality. We show that, compared to a conventional stretcher with the same stretching factor, the transmission-grating based stretcher yields more than an order of magnitude improvement in the contrast pedestal. We have also quantitatively characterized the roughness of the grating surfaces and estimated its impact on the contrast pedestal.

  13. Diagnostic vascular ultrasonography with the help of color Doppler and contrast-enhanced ultrasonography

    PubMed Central

    2016-01-01

    The use of ultrasonography and especially of contrast-enhanced ultrasonography (CEUS) in the diagnosis of vascular pathologies before and after interventions has significantly increased over the past years due to the broader availability of modern ultrasound systems with CEUS capabilities and more trained user experience in this imaging modality. For the preinterventional and postinterventional work-up of carotid diseases, duplex ultrasound as well as CEUS have been established as the standard-of-care examination procedures for diagnosis, evaluation, and follow-up. In addition to its use for carotid arterial diseases, ultrasonography has also become the primary modality for the screening of vascular pathologies. This review describes the most common pathologies found in ultrasonography of the carotid arteries, the abdominal aorta, and the femoral arteries. PMID:27669962

  14. Power constrained contrast enhancement based on brightness compensated contrast-tone mapping operation

    NASA Astrophysics Data System (ADS)

    Jung, Cheolkon; Su, Haonan; Wang, Lu; Ke, Peng

    2016-09-01

    We propose power constrained contrast enhancement based on brightness compensated contrast-tone mapping operation (BCCTMO). We adopt brightness compensation to restore the original perceptual luminance and combine tone mapping with contrast enhancement to improve image quality. First, we increase pixel values to compensate for the reduced brightness caused by backlight dimming while maintaining the perceived luminance. Then we perform a contrast-tone mapping operation to reduce the information loss caused by the brightness compensation and enhance contrast in images. Finally, we conduct color scaling to reproduce natural colors. We implement BCCTMO on an Android tablet with an LCD display using mathematical approximation. Experimental results demonstrate that BCCTMO produces high-quality images while minimizing distortions and saving power compared with state-of-the-art methods.

  15. Comparison of dynamic contrast enhanced MRI and Doppler ultrasound in the pre-operative assessment of the portal venous system.

    PubMed

    Naik, K S; Ward, J; Irving, H C; Robinson, P J

    1997-01-01

    The purpose of this study was to compare dynamic contrast enhanced MRI (DCEMR) with Doppler ultrasound (US) in the assessment of portal venous anatomy and to analyse the causes of discrepancy. Over a 1 year period, 97 patients undergoing assessment prior to hepatic surgery underwent imaging of the liver and portal venous system using US with colour and spectral Doppler and MRI with axial T2 weighted spin echo (SE) and coronal oblique T1 weighted rapid gradient echo (GRE) imaging before and immediately after bolus injection of Gd-DTPA (0.1 mmol kg-1). When the US and MRI findings were discrepant, the images were reviewed by two observers and compared with surgical findings. US and DCEMR were concordant in 90 patients (portal vein patent in 80, occluded in 10). In three patients with cirrhosis and gross ascites the portal vein was reported as occluded on US and patent on MRI; surgery confirmed the MRI findings. In one patient the portal vein was patient on US but not on MRI, but there was a 3 week interval between the examinations. In three patients the portal vein was patent on US, but MRI detected occlusion of intrahepatic portal vein branches in two, and encasement of an intrahepatic branch in the third case. Spontaneous splenorenal shunts were seen in 15 patients only on MRI; varices were seen in 39 patients on MRI and in 22 patients on US. Both US and DCEMR contribute to the pre-operative assessment of the portal venous system. MRI provides additional information over US in assessing intrahepatic portal branches and detecting varices and splenorenal shunts, and is recommended for all surgical candidates and in patients with abnormal portal venous anatomy and equivocal US findings.

  16. Power-constrained contrast enhancement algorithm using multiscale retinex for OLED display.

    PubMed

    Nam, Yeon-Oh; Choi, Dong-Yoon; Song, Byung Cheol

    2014-08-01

    This paper presents a power-constrained contrast enhancement algorithm for organic light-emitting diode display based on multiscale retinex (MSR). In general, MSR, which is the key component of the proposed algorithm, consists of power controllable log operation and subbandwise gain control. First, we decompose an input image to MSRs of different sub-bands, and compute a proper gain for each MSR. Second, we apply a coarse-to-fine power control mechanism, which recomputes the MSRs and gains. This step iterates until the target power saving is accurately accomplished. With video sequences, the contrast levels of adjacent images are determined consistently using temporal coherence in order to avoid flickering artifacts. Finally, we present several optimization skills for real-time processing. Experimental results show that the proposed algorithm provides better visual quality than previous methods, and a consistent power-saving ratio without flickering artifacts, even for video sequences.

  17. Global testicular infarction in the presence of epididymitis: clinical features, appearances on grayscale, color Doppler, and contrast-enhanced sonography, and histologic correlation.

    PubMed

    Yusuf, Gibran; Sellars, Maria E; Kooiman, Gordon G; Diaz-Cano, Salvador; Sidhu, Paul S

    2013-01-01

    Epididymitis is common, presenting indolently with unilateral scrotal pain and swelling. Diagnosis is based on clinical assessment and resolves with antibiotic therapy. Recognized complications are abscess formation and segmental infarction. Global testicular infarction is rare. Diagnosis is important and requires surgical management. On grayscale sonography, global infarction may be difficult to establish. The addition of color Doppler imaging is useful but is observer experience dependent with limitations in the presence of low flow. Contrast-enhanced sonography is useful for unequivocally establishing the diagnosis. We report global testicular infarction in 2 patients with epididymitis clearly depicted on contrast-enhanced sonography, allowing immediate surgical management.

  18. In vivo imaging of melanoma-implanted magnetic nanoparticles using contrast-enhanced magneto-motive optical Doppler tomography

    NASA Astrophysics Data System (ADS)

    Wijesinghe, Ruchire Eranga; Park, Kibeom; Kim, Dong-Hyeon; Jeon, Mansik; Kim, Jeehyun

    2016-06-01

    We conducted an initial feasibility study using real-time magneto-motive optical Doppler tomography (MM-ODT) with enhanced contrast to investigate the detection of superparamagnetic iron oxide (SPIO) magnetic nanoparticles implanted into in vivo melanoma tissue. The MM-ODT signals were detected owing to the phase shift of the implanted magnetic nanoparticles, which occurred due to the action of an applied magnetic field. An amplifier circuit-based solenoid was utilized for generating high-intensity oscillating magnetic fields. The MM-ODT system was confirmed as an effective in vivo imaging method for detecting melanoma tissue, with the performance comparable to those of conventional optical coherence tomography and optical Doppler tomography methods. Moreover, the optimal values of the SPIO nanoparticles concentration and solenoid voltage for obtaining the uppermost Doppler velocity were derived as well. To improve the signal processing speed for real-time imaging, we adopted multithread programming techniques and optimized the signal path. The results suggest that this imaging modality can be used as a powerful tool to identify the intracellular and extracellular SPIO nanoparticles in melanoma tissues in vivo.

  19. Splanchnic Hemodynamics and Intestinal Vascularity in Crohn's Disease: An In Vivo Evaluation Using Doppler and Contrast-Enhanced Ultrasound and Biochemical Parameters.

    PubMed

    Maconi, Giovanni; Asthana, Anil K; Bolzacchini, Elena; Dell'Era, Alessandra; Furfaro, Federica; Bezzio, Cristina; Salvatore, Veronica; Maier, Jeanette A M

    2016-01-01

    Crohn's disease (CD) is characterized by inflammation and angiogenesis of affected bowel. We evaluated the correlation among vascularity of intestinal wall in CD, splanchnic hemodynamics, clinical activity and biochemical parameters of inflammation and angiogenesis. Sixteen patients with ileal CD and 10 healthy controls were investigated by means of Doppler ultrasound of the superior mesenteric artery and color Doppler and contrast-enhanced ultrasound of the ileal wall. In parallel, serum levels of vascular endothelial growth factor, tumor necrosis factor-α (TNF-α) and nitric oxide, before and 30 min after a standard meal, were evaluated. In CD patients, there was a significant post-prandial reduction in the resistance index and pulsatility index of the superior mesenteric artery, associated with increased levels of nitric oxide and decreased amounts of TNF-α. A correlation was observed between vascular endothelial growth factor and contrast-enhanced ultrasound parameters of intestinal wall vascularity (r = 0.63-0.71, p < 0.05) and between these parameters and superior mesenteric artery blood flow after fasting (resistance and pulsatility indexes: r = -0.64 and -0.72, p < 0.05). Our results revealed a post-prandial increase in nitric oxide and decrease in TNF-α in CD patients in vivo. They also confirm the role of vascular endothelial growth factor in angiogenesis and in pathologic vascular remodeling of CD and its effect on splanchnic blood flow.

  20. [Detection of an intrapulmonary shunt in patients with liver cirrhosis through contrast-enhanced transcranial Doppler. A study of prevalence, pattern characterization, and diagnostic validity].

    PubMed

    Ramírez Moreno, José María; Millán Núñez, María Victoria; Rodríguez Carrasco, Marta; Ceberino, David; Romaskevych-Kryvulya, Olena; Constantino Silva, Ana Belén; Muñoz-Vega, Pedro; García-Corrales, Carmen; Guiberteau-Sánchez, Ana; Roa Montero, Ana; Márquez-Lozano, Patricia; Narváez Rodríguez, Isidoro

    2015-10-01

    Intrapulmonary vascular dilatations (IPVD) are considered a complication of cirrhosis. The technique of choice for their diagnosis is contrast-enhanced echocardiography (CEE). The aim of this study was to determine the usefulness of contrast-enhanced transcranial Doppler (CETD) in the diagnosis of IPVD. We consecutively included patients evaluated for liver transplantation. A cross-sectional study was conducted. The investigator interpreting CETD was blind to the results of the gold standard (CEE). The accuracy of the diagnostic test was evaluated through sensitivity, specificity, positive and negative predictive values, and likelihood ratio. CETD (n=43) showed a right-to-left shunt in 23 patients (62.2%): 4 early, 2 indeterminate and 17 late. Nineteen (51,4%) cases were classified as IPVD. With CEE (n=37), 10 procedures (27%) were negative for shunt, 27 (73%) were positive, and 21 (56.8%) were compatible with IPVD. Patients with and without IPVD showed no differences in age, sex, etiology, severity, or MELD score, independently of the diagnostic test. In the diagnostic validity study (n=37) of CETD versus CEE, the AUC for diagnostic yield was 0.813% (95%CI: 0.666-0.959; P=.001), sensitivity was 76.2% (95%CI: 54.9-89.4) and specificity was 90% (95%CI: 63.9-96.5). The positive likelihood ratio was 6.095. We found a high prevalence of IPVD in candidates for liver transplantation. When a late right-to-left shunt with recirculation is observed, CETD has a high probability of detecting IPVD, with few false-positive results. Because this technique has not previously been described in this indication, similar studies are needed for comparison. Copyright © 2015 Elsevier España, S.L.U. and AEEH y AEG. All rights reserved.

  1. Assessment of peripheral skeletal muscle microperfusion in a porcine model of peripheral arterial stenosis by steady-state contrast-enhanced ultrasound and Doppler flow measurement.

    PubMed

    Naehle, Claas P; Steinberg, Verena A; Schild, Hans; Mommertz, Gottfried

    2015-05-01

    Noninvasive measurement of peripheral muscle microperfusion could potentially improve diagnosis, management, and treatment of peripheral arterial disease (PAD) and thus improve patient care. Contrast-enhanced ultrasound (CEUS) as a noninvasive diagnostic tool allows quantification of muscle perfusion. Increasing data on bolus technique CEUS reflecting microperfusion are becoming available, but only limited data on steady-state CEUS for assessment of muscle microperfusion are available. Therefore, the aim of this study was to evaluate steady-state CEUS for assessment of peripheral muscle microperfusion in a PAD animal model. In a porcine animal model, peripheral muscle microperfusion was quantified by steady-state CEUS replenishment kinetics (mean transit time [mTT] and wash-in rate [WiR]) of the biceps femoris muscle during intravenous steady-state infusion of INN-sulfur hexafluoride (SonoVue; Bracco, Geneva, Switzerland). In addition, macroperfusion was quantified at the external femoral artery with a Doppler flow probe. Peripheral muscle microperfusion and Doppler flow measurements were performed bilaterally at rest and under adenosine stress (70 μg/kg body weight) before and after unilateral creation of a moderate external iliac artery stenosis. All measurements could be performed completely in 10 pigs. Compared with baseline measurements, peripheral muscle microperfusion decreased significantly during adenosine stress (rest vs adenosine stress: mTT, 7.8 ± 3.3 vs 21.2 ± 17.8 s, P = .0006; WiR, 58.4 ± 38.1 vs 25.3 ± 15.6 arbitrary units [a.u.]/s, P < .0001; Doppler flow, 122.3 ± 31.4 vs 83.6 ± 28.1 mL/min, P = .0067) and after stenosis creation (no stenosis vs stenosis: mTT, 8.1 ± 3.1 vs 29.2 ± 18.0 s, P = .0469; WiR, 53.0 ± 22.7 vs 13.6 ± 8.4 a.u./s, P = .0156; Doppler flow, 124.2 ± 41.8 vs 65.9 ± 40.0 mL/min, P = .0313). After stenosis creation, adenosine stress led to a further significant decrease of peripheral muscle microperfusion but had no

  2. Right-to-left shunt detection using contrast-enhanced transcranial Doppler: A comparison of provocation maneuvers between coughing and a modified Valsalva maneuver

    PubMed Central

    Wang, Si-Bo; Wang, Xiao-Cong; Ma, Yan; Liu, Kang-Ding

    2017-01-01

    Contrast-enhanced transcranial Doppler (c-TCD) has been used to detect right-to-left shunts (RLS) because it is highly sensitive and cost-effective. The use of provocation maneuvers, such as physiologic maneuvers (e.g., coughing) and the Valsalva maneuver (VM) to transiently increase right atrial pressure and induce RLS increases the sensitivity of RLS detection. In this study, we sought to determine whether coughing is as effective as the VM in aiding the detection of RLS. We evaluated 162 subjects for RLS, using c-TCD under three different conditions: (i) resting state, (ii) coughing, and (iii) modified VM (m-VM), which involved blowing into a tube connected to a sphygmomanometer at 40 mmHg for 10 s. The positive rate of RLS detection with the m-VM was significantly higher than that with coughing. In addition, a difference between the two maneuvers was observed in terms of the degree of RLS seen. The m-VM should be widely used to detect RLS, because it is reliable, standardized, and cost-effective. PMID:28384297

  3. Contrast-enhanced ultrasound in combination with color Doppler ultrasound can improve the diagnostic performance of focal nodular hyperplasia and hepatocellular adenoma.

    PubMed

    Kong, Wen-Tao; Wang, Wen-Ping; Huang, Bei-Jian; Ding, Hong; Mao, Feng; Si, Qin

    2015-04-01

    The aim of our study was to evaluate the value of combining color Doppler ultrasound (CDUS) with contrast-enhanced ultrasound (CEUS) in identifying and comparing features of focal nodular hyperplasia (FNH) and hepatocellular adenoma (HCA). Thirty-eight patients with FNH (n = 28) or HCA (n = 10), whose diagnoses were later confirmed by pathology, were examined with conventional ultrasonography and CEUS between 2010 and 2013. Two doctors blinded to the pathology results independently reviewed the conventional ultrasound and CEUS images and then reached a consensus through discussion. The following parameters evaluated for all lesions included vascularity pattern on CDUS or CEUS, enhancement characteristics on CEUS and the presence of a central scar. Statistical analysis was performed with the independent sample t-test and Fisher exact test. On CDUS, FNH was characterized by the presence of abundant blood flow signals exhibiting dendritic (53.6%, 15/28) and spoke-wheel (28.6%, 8/28) patterns, whereas blood flow signal of HCA was slightly less than FNH and often showed subcapsular short rod-like (50%, 5/10) appearance. On CEUS, the most common arterial enhancement pattern was centrifugal or homogeneous enhancement in FNH (both, 12/28, 42.9%) and homogeneous enhancement in HCA (6/10, 60%). Spoke-wheel arteries, feeding artery and central scar were detected in 5 (17.9%), 8 (28.6%) and 5 (17.9%) of 28 FNHs. Hypo-echogenic pattern during delayed phase was more common in HCA (60%, 6/10) than in FNH (3/28, 10.7%) (p = 0.010). A total of 25 (25/38, 65.8%) lesions were correctly assessed using CDUS in combination with CEUS, whereas the number decreased to 15 (15/38, 39.5%) when CDUS was used alone (p = 0.038). The areas under the ROC curves before and after CEUS administration were 0.768 and 0.879, respectively. In conclusion, CEUS in combination with CDUS improve the diagnostic performance of FNH and HCA. Blood signal of HCA was less than FNH on CDUS. The differences of

  4. Value of contrast-enhanced ultrasound in rheumatic disease.

    PubMed

    Klauser, Andrea Sabine

    2005-12-01

    Ultrasound (US) is a useful tool in the assessment of rheumatic disease. It permits assessment of early erosive changes and vascularity detection in synovial proliferation, caused by inflammatory activity by using colour/power Doppler US (CDUS/PDUS). In the detection of slow flow and flow in small vessels, the CDUS/PDUS technique is limited. Contrast enhanced US can improve the detection of inflammatory vascularity but is not yet included in routine diagnosis of this condition. However, contrast enhanced US shows promising results in diagnosis, assessment of disease activity and follow up of inflammatory rheumatic diseases.

  5. Contrast-enhanced harmonic ultrasonography of medial iliac lymph nodes in healthy dogs.

    PubMed

    Gaschen, Lorrie; Angelette, Nik; Stout, Rhett

    2010-01-01

    Herein, we describe the normal contrast-enhanced harmonic, color, and power Doppler ultrasonographic characteristics of the medial iliac lymph nodes in healthy dogs. Contrast-enhanced harmonic ultrasonography of the medial iliac lymph nodes was performed on 14 healthy dogs after intravenous administration of the lipoprotein-bound inert gas-filled microbubble contrast media Definity. Time-pixel intensity curves were generated for 1-min postinjection. Quantification of these curves was performed using Philips QLab software. Non-contrast-enhanced power and color Doppler examinations were performed in each node to assess vascular patterns subjectively. Normal lymph nodes exhibited a mean contrast wash-in phase beginning at 6.3 s from the time of injection with mean peak pixel intensity at 12.1s. Angioarchitecture was best visualized with contrast-enhanced harmonic ultrasound compared with power and color Doppler. Normal lymph nodes in dogs have a central artery with a centrifugal and uniform branching pattern. Contrast-enhanced harmonic ultrasonography is a noninvasive examination that demonstrates improved visibility of the intranodal architecture of healthy medial iliac lymph nodes in dogs compared with conventional, non-contrast-enhanced Doppler methods that may have future clinical applications.

  6. [Power Doppler e mezzi di contrasto nello studio della membrana sinoviale reumatoide].

    PubMed

    Carotti, M; Filippucci, E; Salaffi, F

    2002-01-01

    Pannus formation is a fundamental event in the pathogenesis of rheumatoid arthritis and its hypervascularisation seems to be crucial to the development of joint damage. High-resolution greyscale ultrasonography is a safe, quick, and inexpensive imaging tool that allows an accurate detection of even minimal morphostructural changes in patients with rheumatoid arthritis, including joint effusion, thickening of synovial membrane and bone erosions. More recently, power Doppler sonography has proved to be a reliable tool for semiquantitative assessment of the vascularity of the synovial tissue. The contrast-enhanced power Doppler sonography seems to be a helpful adjunct in assessing synovitis and the therapeutic response to the different therapies in patients with rheumatoid arthritis. The aim of this radiological vignette was to show a representative example of use of power Doppler sonography with contrast agent in assessing rheumatoid synovitis.

  7. Power modulation contrast enhanced ultrasound for postoperative perfusion monitoring following free tissue transfer in head and neck surgery.

    PubMed

    Sharma, S; Anand, R; Hickman, M; Senior, R; Walji, S; Ramchandani, P L; Culliford, D; Ilankovan, V; Greaves, K

    2010-12-01

    This feasibility study evaluated whether contrast enhanced ultrasound (CEU) was able to assess free flap perfusion following free tissue transfer in the head and neck region. Thirty-six patients underwent standard clinical monitoring (SCM) and CEU postoperatively. The time taken for each technique to detect flap failure was recorded. Qualitative CEU analysis by visual assessment predicted survival in 30/30 (100%) and failure in 5/6 (83%) flaps with sensitivity, specificity, positive (PPV) and negative (NPV) predictive values of 100, 86, 97 and 100%, respectively. Quantitative CEU measurement of blood volume (α) values within healthy perfused flaps was over 60 times higher than in failing flaps (8.25±2.82dB vs. 0.12±0.17dB, respectively, P<0.0001). If a cut-off α value of <1.5dB was used to predict future flap failure, the accuracy of the test was 100% (sensitivity, specificity, PPV, NPV). If a cut-off α value of >1.9dB indicated flap success, the PPV and NPV are 100%. Following surgery, SCM took 76 (±15) h to detect flap failure compared with 18 (±38) h with CEU (P<0.05). CEU is highly accurate in its ability to distinguish between perfused and failing flaps. The technique is quick (<10min) and capable of imaging all flap types.

  8. Effect of Peripheral Artery Sympathetic Denervation on Muscle Microperfusion and Macroperfusion in an Animal Peripheral Artery Disease Model Using Contrast-Enhanced Ultrasound and Doppler Flow Measurement.

    PubMed

    Steinberg, Verena A; Mommertz, Gottfried; Thiesler, Thore; Kristiansen, Glen; Schild, Hans; Naehle, Claas P

    2015-09-01

    To determine the effects of catheter-based peripheral sympathetic denervation (CPSD) on peripheral artery sympathetic tone and peripheral microperfusion (PMP). The effects of bilateral CPSD in common iliac arteries on PMP of the biceps femoris were determined in pigs using contrast-enhanced ultrasound, and mean transit time (mTT) and wash-in rate (WiR) were calculated during steady-state infusion of INN-sulfur-hexafluoride. Measurements were performed bilaterally at rest and during infusion of adenosine 70 μg/kg/min after unilateral moderate left external iliac artery stenosis. Before CPSD, PMP decreased significantly (P < .05) under adenosine stress compared with resting conditions, with right mTT of 7.5 seconds ± 3.6 versus 16.9 seconds ± 11.9 and WiR of 63.1 arbitrary units (AU) ± 49.0 versus 25.0 AU ± 17.5 and left mTT of 29.2 seconds ± 18.0 versus 56.3 seconds ± 38.7 and WiR of 13.6 AU ± 8.4 versus 6.0 AU ± 4.1. After CPSD, PMP did not differ significantly (P > .05) between conditions of adenosine stress and rest, with right mTT of 19.9 seconds ± 24.7 versus 23.2 seconds ± 21.0 and WiR of 16.2 AU ± 25.0 versus 20.5 AU ± 19.7 and left mTT of 23.3 seconds ± 23.1 versus 25.8 seconds ± 21.7 and WiR of 12.5 AU ± 6.2 versus 20.0 AU ± 12.1. CPSD reduced peripheral artery sympathetic tone and may be an alternative to surgical or computed tomography-guided sympathectomy for the treatment of end-stage peripheral artery disease and Raynaud phenomenon. Copyright © 2015 SIR. Published by Elsevier Inc. All rights reserved.

  9. Measurement of the Doppler power of flowing blood using ultrasound Doppler devices.

    PubMed

    Huang, Chih-Chung; Chou, Hung-Lung; Chen, Pay-Yu

    2015-02-01

    Measurement of the Doppler power of signals backscattered from flowing blood (henceforth referred to as the Doppler power of flowing blood) and the echogenicity of flowing blood have been used widely to assess the degree of red blood cell (RBC) aggregation for more than 20 y. Many studies have used Doppler flowmeters based on an analogue circuit design to obtain the Doppler shifts in the signals backscattered from flowing blood; however, some recent studies have mentioned that the analogue Doppler flowmeter exhibits a frequency-response problem whereby the backscattered energy is lost at higher Doppler shift frequencies. Therefore, the measured Doppler power of flowing blood and evaluations of RBC aggregation obtained using an analogue Doppler device may be inaccurate. To overcome this problem, the present study implemented a field-programmable gate array-based digital pulsed-wave Doppler flowmeter to measure the Doppler power of flowing blood, in the aim of providing more accurate assessments of RBC aggregation. A clinical duplex ultrasound imaging system that can acquire pulsed-wave Doppler spectrograms is now available, but its usefulness for estimating the ultrasound scattering properties of blood is still in doubt. Therefore, the echogenicity and Doppler power of flowing blood under the same flow conditions were measured using a laboratory pulser-receiver system and a clinical ultrasound system, respectively, for comparisons. The experiments were carried out using porcine blood under steady laminar flow with both RBC suspensions and whole blood. The experimental results indicated that a clinical ultrasound system used to measure the Doppler spectrograms is not suitable for quantifying Doppler power. However, the Doppler power measured using a digital Doppler flowmeter can reveal the relationship between backscattering signals and the properties of blood cells because the effects of frequency response are eliminated. The measurements of the Doppler power and

  10. Ultrasound imaging for the rheumatologist. XVII. Role of colour Doppler and power Doppler.

    PubMed

    Iagnocco, A; Epis, O; Delle Sedie, A; Meenagh, G; Filippucci, E; Riente, L; Scirè, C A; Montecucco, C; Bombardieri, S; Grassi, W; Valesini, G

    2008-01-01

    The use of Doppler ultrasound in rheumatology has grown in recent years. This is partly due to the increasing number of rheumatologists who perform US in their daily clinical practise and also to the technological advances of US systems. Both colour Doppler and power Doppler are used to evaluate the degree of intra- and peri-articular soft tissue inflammation. Moreover, Doppler US has been found to be of help in the assessment of vascular pathologies such as the vasculitides. In this review we provide an update of the data regarding the use of colour Doppler and power Doppler in rheumatology.

  11. Prototype vein contrast enhancer

    NASA Astrophysics Data System (ADS)

    Zeman, Herbert D.; Lovhoiden, Gunnar; Vrancken, Carlos

    2004-07-01

    A proof-of-principle prototype Vein Contrast Enhancer (VCE) has been designed and constructed. The VCE is an instrument that makes vein access easier by capturing an infrared image of peripheral veins, enhancing the vein-contrast using software image processing, and projecting the enhanced vein-image back onto the skin using a modified commercial projector. The prototype uses software alignment to achieve alignment accuracy between the captured infrared image and the projected visible image of better than 0.06 mm. Figure 1 shows the prototype demonstrated in our laboratory.

  12. Echo-power estimation from log-compressed video data in dynamic contrast-enhanced ultrasound imaging.

    PubMed

    Payen, Thomas; Coron, Alain; Lamuraglia, Michele; Le Guillou-Buffello, Delphine; Gaud, Emmanuel; Arditi, Marcel; Lucidarme, Olivier; Bridal, S Lori

    2013-10-01

    Ultrasound (US) scanners typically apply lossy, non-linear modifications to the US data for visualization purposes. The resulting images are then stored as compressed video data. Some system manufacturers provide dedicated software for quantification purposes to eliminate such processing distortions, at least partially. This is currently the recommended approach for quantitatively assessing changes in contrast-agent concentration from clinical data. However, the machine-specific access to US data and the limited set of analysis functionalities offered by each dedicated-software package make it difficult to perform comparable analyses with different US systems. The objective of this work was to establish if linearization of compressed video images obtained with an arbitrary US system can provide an alternative to dedicated-software analysis of machine-specific files for the estimation of echo-power. For this purpose, an Aplio 50 system (Toshiba Medical Systems, Tochigi, Japan), coupled with dedicated CHI-Q (Contrast Harmonic Imaging Quantification) software by Toshiba Medical Systems, was used. Results were compared with two approaches that apply algorithms to estimate relative echo-power from compressed video images: commercially available VueBox software by Bracco Suisse SA (Geneva, Switzerland) and in-laboratory software called PixPower. The echo-power estimated by CHI-Q analysis indicated a strong linear relationship versus agent concentration in vitro (R(2) ≥ 0.9996) for dynamic range (DR) settings of DR60 and DR80, with slopes between 9.22 and 9.57 dB/decade (p = 0.05). These values approach the theoretically predicted dependence of 10.0 dB/decade (equivalent to 3 dB for each concentration doubling). Echo-power estimations obtained from compressed video images with VueBox and PixPower also exhibited strong linear proportionality with concentration (R(2) ≥ 0.9996), with slopes between 9.30 and 9.68 dB/decade (p = 0.05). On an independent in vivo data set (N

  13. Combined assessment of myocardial perfusion and regional left ventricular function by analysis of contrast-enhanced power modulation images.

    PubMed

    Mor-Avi, V; Caiani, E G; Collins, K A; Korcarz, C E; Bednarz, J E; Lang, R M

    2001-07-17

    Echocardiographic contrast media have been used to assess myocardial perfusion and to enhance endocardial definition for improved assessment of left ventricular (LV) function. These methodologies, however, have been qualitative or have required extensive offline image analysis. Power modulation is a recently developed imaging technique that provides selective enhancement of microbubble-generated reflections. Our goal was to test the feasibility of using power modulation for combined quantitative assessment of myocardial perfusion and regional LV function in an animal model of acute ischemia. Coronary balloon occlusions were performed in 18 anesthetized pigs. Transthoracic power modulation images (Agilent 5500) were obtained during continuous intravenous infusion of the contrast agent Definity (DuPont) at baseline and during brief coronary occlusion and reperfusion and were analyzed with custom software. At each phase, myocardial perfusion was assessed by calculation, in 6 myocardial regions of interest, of mean pixel intensity and the rate of contrast replenishment after high-power ultrasound impulses. LV function was assessed by calculation of regional fractional area change from semiautomatically detected endocardial borders. All ischemic episodes caused detectable and reversible changes in perfusion and function. Perfusion defects, validated with fluorescent microspheres, were visualized in real time and confirmed by a significant decrease in pixel intensity in the left anterior descending coronary artery territory after balloon inflation and reduced rate of contrast replenishment. Fractional area change decreased significantly in ischemic segments and was restored with reperfusion. Power modulation allows simultaneous online assessment of myocardial perfusion and regional LV wall motion, which may improve the echocardiographic diagnosis of myocardial ischemia.

  14. Ultrasonography with color Doppler and power Doppler in the diagnosis of periapical lesions

    PubMed Central

    Goel, Sumit; Nagendrareddy, Suma Gundareddy; Raju, Manthena Srinivasa; Krishnojirao, Dayashankara Rao Jingade; Rastogi, Rajul; Mohan, Ravi Prakash Sasankoti; Gupta, Swati

    2011-01-01

    Aim: To evaluate the efficacy of ultrasonography (USG) with color Doppler and power Doppler applications over conventional radiography in the diagnosis of periapical lesions. Materials and Methods: Thirty patients having inflammatory periapical lesions of the maxillary or mandibular anterior teeth and requiring endodontic surgery were selected for inclusion in this study. All patients consented to participate in the study. We used conventional periapical radiographs as well as USG with color Doppler and power Doppler for the diagnosis of these lesions. Their diagnostic performances were compared against histopathologic examination. All data were compared and statistically analyzed. Results: USG examination with color Doppler and power Doppler identified 29 (19 cysts and 10 granulomas) of 30 periapical lesions accurately, with a sensitivity of 100% for cysts and 90.91% for granulomas and a specificity of 90.91% for cysts and 100% for granulomas. In comparison, conventional intraoral radiography identified only 21 lesions (sensitivity of 78.9% for cysts and 45.4% for granulomas and specificity of 45.4% for cysts and 78.9% for granulomas). There was definite correlation between the echotexture of the lesions and the histopathological features except in one case. Conclusions: USG imaging with color Doppler and power Doppler is superior to conventional intraoral radiographic methods for diagnosing the nature of periapical lesions in the anterior jaws. This study reveals the potential of USG examination in the study of other jaw lesions. PMID:22223940

  15. Quantification of left ventricular size and function using contrast-enhanced real-time 3D imaging with power modulation: comparison with cardiac MRI.

    PubMed

    Coon, Patrick D; Pollard, Heidi; Furlong, Kathleen; Lang, Roberto M; Mor-Avi, Victor

    2012-11-01

    In patients with optimal images, real-time 3-D echocardiography (RT3DE) allows accurate evaluation of left ventricular (LV) volumes and ejection fraction (EF). However, in patients with poor acoustic windows, lower correlations were reported despite the use of contrast. We hypothesized that power modulation (PM) RT3DE imaging that uses low mechanical indices and provides uniform LV opacification could overcome this problem. Accordingly, we sought to: (i) Test the feasibility of quantification of LV volumes and EF from contrast-enhanced (CE) PM RT3DE images, (ii) validate this technique against cardiac magnetic resonance (CMR) reference and (iii) test its clinical value by quantifying the improvement in accuracy and reproducibility. We studied 20 patients who underwent CMR, harmonic nonenhanced RT3DE and CE PM RT3DE imaging on the same day. All images were analyzed to obtain end-systolic and end-diastolic LV volumes (EDV, ESV) and calculate EF. To determine the reproducibility of each RT3DE technique, imaging was repeated in the same setting by a second sonographer. In addition, patients were divided according to the quality of their RT3DE images into two groups, for which agreement with CMR and reproducibility were calculated separately. CE PM RT3DE imaging improved the accuracy of EDV, ESV and EF measurements in patients with poor acoustic windows without significantly affecting those in patients with optimal images. In addition, CE PM RT3DE imaging improved the reproducibility of the measurements, as reflected by a twofold decrease in intermeasurement variability. Importantly, the variability in CE PM RT3DE-derived volumes and EF was under 10%, irrespective of image quality. This methodology may become the new standard for LV size and function, which will be particularly important in patients with poor acoustic windows or contraindications to CMR. Copyright © 2012 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights

  16. Ultrasound Despeckling for Contrast Enhancement

    PubMed Central

    Tay, Peter C.; Garson, Christopher D.; Acton, Scott T.; Hossack, John A.

    2010-01-01

    Images produced by ultrasound systems are adversely hampered by a stochastic process known as speckle. A despeckling method based upon removing outlier is proposed. The method is developed to contrast enhance B-mode ultrasound images. The contrast enhancement is with respect to decreasing pixel variations in homogeneous regions while maintaining or improving differences in mean values of distinct regions. A comparison of the proposed despeckling filter is compared with the other well known despeckling filters. The evaluations of despeckling performance are based upon improvements to contrast enhancement, structural similarity, and segmentation results on a Field II simulated image and actual B-mode cardiac ultrasound images captured in vivo. PMID:20227984

  17. Complete penile corporeal septation: evaluation with contrast enhanced US.

    PubMed

    Bertolotto, Michele; Bucci, Stefano; Quaia, Emilio; Coss, Matteo; Liguori, Giovanni

    2008-01-01

    Complete penile corporeal septation is a rare malformation in which the corpora cavernosa are completely isolated. We describe a new method to reach the diagnosis of this malformation using contrast enhanced US. Two patients with complete penile corporeal septation underwent color Doppler and contrast enhanced US after bilateral cavernosal injection of 10 microg prostaglandin E1. Contrast enhanced US was performed using a contrast specific software (Contrast-Tuned imaging, EsaOte, Genoa, Italy) and a linear transducer designed to evaluate superficial structures. Microbubbles of SonoVue (Bracco, Milan, Italy) were injected in one corpus cavernosum. After cavernosal injection of microbubbles no adverse events were observed. Contrast enhanced US showed unilateral enhancement of the corpus cavernosum in which microbubbles were injected. Cavernosography confirmed unilateral corporeal opacification. Contrast enhanced US can be used effectively to diagnose complete penile corporeal septation.

  18. Fuzzy-Contextual Contrast Enhancement.

    PubMed

    Parihar, Anil; Verma, Om; Khanna, Chintan

    2017-02-08

    This paper presents contrast enhancement algorithms based on fuzzy contextual information of the images. We introduce fuzzy similarity index and fuzzy contrast factor to capture the neighborhood characteristics of a pixel. A new histogram, using fuzzy contrast factor of each pixel is developed, and termed as the fuzzy dissimilarity histogram (FDH). A cumulative distribution function (CDF) is formed with normalized values of FDH and used as a transfer function to obtain the contrast enhanced image. The algorithm gives good contrast enhancement and preserves the natural characteristic of the image. In order to develop a contextual intensity transfer function, we introduce a fuzzy membership function based on fuzzy similarity index and coefficient of variation of the image. The contextual intensity transfer function is designed using the fuzzy membership function to achieve final contrast enhanced image. The overall algorithm is referred as the fuzzy contextual contrast-enhancement (FCCE) algorithm. The proposed algorithms are compared with conventional and state-of-art contrast enhancement algorithms. The quantitative and visual assessment of the results is performed. The results of quantitative measures are statistically analyzed using t-test. The exhaustive experimentation and analysis show the proposed algorithm efficiently enhances contrast and yields in natural visual quality images.

  19. Power Doppler evaluation of revascularization in childhood moyamoya.

    PubMed

    Perren, F; Meairs, S; Schmiedek, P; Hennerici, M; Horn, P

    2005-02-08

    Moyamoya disease is generally recognized in young children. One potential treatment is direct extra-intracranial bypass combined with indirect revascularization using encephalo-myo-synangiosis. Standard follow-up to assess neoangiogenesis includes repeat cerebral angiography, which is invasive. The authors studied whether noninvasive power Doppler imaging could evaluate the patency of the bypass and the degree of indirect revascularization. They found that transcranial power Doppler imaging is a valid noninvasive alternative to cerebral angiography.

  20. Intraluminal ultrasound intensity distribution and backscattered Doppler power.

    PubMed

    Thompson, Rosemary S; Bambi, Giacomo; Steel, Robin; Tortoli, Piero

    2004-11-01

    Ultrasound (US) incident obliquely on a cylindrical vessel is redistributed in space when the propagation path includes walls with acoustic impedance different from that of the surrounding media. We investigated this using low-density polyethylene (PE) as the vessel wall material. Both simulations and experiments were carried out. Direct hydrophone measurements of the acoustic field were made within a half section of the PE tube, and the distribution of backscattered Doppler power along a scan line was obtained using a range-Doppler instrument. Both simulation and hydrophone results demonstrate lateral shadow regions within the lumen. In every one of various Doppler flow experiments conducted, the backscattered Doppler power, compensated for on-axis transducer behaviour, increased with depth. Simulation results for an incident continuous-wave (CW) plane wave show that it tends to be focused by the curvature of the PE tube walls. The wall interactions are, however, angle-dependent and so the behaviour of a focused US beam depends on the beam as well as the walls. This study demonstrates alterations in the spatial distribution of US within a cylindrical vessel as a result of known vessel wall properties. It also provides evidence that local intensity variations within the lumen affect the relative Doppler power backscattered from small sample volumes.

  1. Power Doppler ultrasound appearances of neonatal ischaemic brain injury.

    PubMed

    Steventon, D M; John, P R

    1997-02-01

    Following neonatal ischaemic brain injury, irregular vessels increase in size owing to luxury perfusion. These may be demonstrated by conventional colour flow Doppler (CFD) imaging at the periphery of the infarcted area. We present a case in which power Doppler imaging (PDI) was performed in addition to CFD in a neonate with unexplained seizures and which proved more sensitive than CFD in demonstrating luxury perfusion. Ultrasound appearances were compared with those seen on cranial CT. PDI can be a useful adjunct to conventional CFD examination of the neonatal brain in cerebral infarction.

  2. Renal power Doppler ultrasonographic evaluation of children with acute pyelonephritis.

    PubMed

    Shajari, Ahmad; Nafisi-Moghadam, Reza; Malek, Mahrooz; Smaili, Agha; Fallah, Mahmud; Pahlusi, Ali

    2011-01-01

    Urinary tract infections are common in children. The available gold standard method for diagnosis, Tc-99m dimercaptosuccinic acid scan is expensive and exposes patients to considerable amount of radiation. This study was performed to compare and assess the efficacy of Power Doppler Ultrasound versus Tc-99m DMSA scan for diagnosis of acute pyelonephritis. A quasi experimental study was conducted on 34 children with mean age of 2.8 ± 2.7 years who were hospitalized with their first episode of febrile urinary tract infection. All children were evaluated in the first 3 days of admission by Doppler Ultrasound and Tc-99m DMSA scan. Patients with congenital structural anomalies were excluded. Each kidney was divided into three zones. The comparison between efficacy of Doppler Ultrasound and DMSA scan was carried out based on number of patients and on classified renal units. Based on the number of patients enrolled; the sensitivity, specificity, positive and negative predictive values and accuracy of Doppler Ultrasound were 89%, 53%, 70%, 80% and 74%, respectively but based on the renal units, it was 66%, 81%, 46%, 91% and 79% , respectively. Although Doppler Ultrasound has the potential for identifying acute pyelonephritis in children, but it is still soon to replace DMSA scan.

  3. Commercialization of vein contrast enhancement

    NASA Astrophysics Data System (ADS)

    Lovhoiden, Gunnar; Deshmukh, Harshal; Vrancken, Carlos; Zhang, Yong; Zeman, Herbert D.; Weinberg, Devin

    2003-07-01

    An ongoing clinical study of an experimental infrared (IR) device, the Vein Contrast Enhancer (VCE) that visualizes surface veins for medical access, indicates that a commercial device with the performance of the existing VCE would have significant clinical utility for even a very skilled phlebotomist. A proof-of-principle prototype VCE device has now been designed and constructed that captures IR images of surface veins with a commercial CCD camera, transfers the images to a PC for real-time software image processing to enhance the vein contrast, and projects the enhanced images back onto the skin with a modified commercial LCD projector. The camera and projector are mounted on precision slides allowing for precise mechanical alignment of the two optical axes and for measuring the effects of axes misalignment. Precision alignment of the captured and projected images over the entire field-of-view is accomplished electronically by software adjustments of the translation, scaling, and rotation of the enhanced images before they are projected back onto the skin. This proof-of-principle prototype will be clinically tested and the experience gained will lead to the development of a commercial device, OnTarget!, that is compact, easy to use, and will visualize accessible veins in almost all subjects needing venipuncture.

  4. Comparison of harmonic and conventional power Doppler ultrasonography for assessment of slow flow in hyperechoic tissue: experimental study using a Doppler phantom.

    PubMed

    Kim, A Y; Kim, T K; Kim, Y H; Han, J K; Choi, B I

    2000-02-01

    Despite the advantages of depicting slow flow in small vessels, conventional power Doppler ultrasound (US) has a basic limitation, specifically that artifactual power Doppler signals mimic blood flow, especially in hyperechoic tissue. The purpose of this study was to compare harmonic power Doppler US with power Doppler US using a Doppler phantom under various parameter settings, focusing on the assessment of slow flow in the hyperechoic tissue. While controlling the flow velocity (5 and 10 cm/s), pulse repetition frequency (500, 700, and 1,000 Hz), wall filter (low and medium), and Doppler gain (90%, 96%, and 100%), the authors performed both harmonic Doppler US and power Doppler US by using a Doppler phantom/flow control system. We measured and compared the relative intensities of the Doppler signals (0-250 scale) in both the vessels and hyperechoic tissue-mimicking materials with the two different imaging modalities. Power Doppler US with any combination of the four parameters evaluated depicted strong flow signals (mean, 213) that were superior to harmonic Doppler US (mean, 61). Relatively strong artifactual signals within the hyperechoic tissue-mimicking materials were noted on all power Doppler US studies (mean, 106) but nearly none on harmonic Doppler US (mean, 3). The contrast-to-noise ratio of harmonic Doppler US was significantly greater than that of power Doppler US. Harmonic Doppler US is more useful in assessing slow flow in hyperechoic tissue than power Doppler US because it produces fewer artifactual Doppler signals originating from stationary hyperechoic tissues, which can be misjudged as true signals on power Doppler US.

  5. Power Doppler ultrasonography of painful Achilles tendons and entheses in patients with and without spondyloarthropathy: a comparison with clinical examination and contrast-enhanced MRI.

    PubMed

    Wiell, Charlotte; Szkudlarek, Marcin; Hasselquist, Maria; Møller, Jakob M; Nørregaard, Jesper; Terslev, Lene; Ostergaard, Mikkel

    2013-03-01

    The objective of this study was to describe ultrasonography (US) and magnetic resonance imaging (MRI) findings at painful Achilles tendons and entheses in patients with and without spondyloarthropathy (SpA and non-SpA) and healthy control persons (CTRLs). Particularly, we aimed to investigate if any changes differentiate SpA from non-SpA. Finally, we investigated the reliability of US compared to clinical examination of Achilles tendinopathy, using MRI as gold standard reference. Twelve SpA patients and 15 non-SpA patients with pain and tenderness at at least one Achilles tendon and/or enthesis due to sports-related causes and 10 CTRLs were examined at the Achilles tendons and entheses with US, MRI and clinical assessment. Intratendinous changes, entheseal changes, bursitis and peritendonitis were assessed. An US interobserver substudy was performed in nine persons. US findings showed high agreement between observers (median 89 %, κ = 0.64) and with MRI (median 89 %, κ = 0.74). All inflammatory intratendinous changes were less frequent in SpA than non-SpA patients (p < 0.05). Entheseal changes and bursitis were found equally frequent in both patient groups except for enthesophytes, which were most common in the SpA group (p < 0.01). No findings were exclusively found in SpA. When MRI was considered gold standard, US showed higher sensitivity for intratendinous and entheseal changes than clinical examination (median sensitivity 0.83 versus 0.66). Especially, entheseal changes had higher sensitivity than clinical examination without loss of specificity. In conclusion, US performed by a trained operator can be a useful adjunct to clinical examination for improved assessment of Achilles tendons and entheses.

  6. Dynamic Contrast-Enhanced Digital Breast Tomosynthesis

    DTIC Science & Technology

    2012-03-01

    11-1-0229 TITLE: Dynamic Contrast-Enhanced Digital Breast Tomosynthesis PRINCIPAL INVESTIGATOR: Dr. Andrew Maidment...5 Introduction We propose a new technique for obtaining 4D dynamic contrast-enhanced (DCE) digital breast tomosynthesis (DBT) im...seconds. One com plete tomosynthesis projection series consists of a set of projection im ages acquired at distinct angles. In the proposed m ethod

  7. Contrast enhanced ultrasound by real-time spatiotemporal filtering of ultrafast images

    NASA Astrophysics Data System (ADS)

    Desailly, Yann; Tissier, Anne-Marie; Correas, Jean-Michel; Wintzenrieth, Frédéric; Tanter, Mickaël; Couture, Olivier

    2017-01-01

    Contrast enhanced ultrasound (CEUS) takes advantage of the nonlinear behaviour of injected microbubbles. If these contrast techniques yield good specificity between bubbles and tissues, they suffer some drawbacks, inherently linked to their dependence on nonlinear content. In recent years, plane-wave ultrasound reached frame rates of up to 20 000 fps. In this study we propose a linear technique for CEUS that takes advantage of these very high frame rates to separate bubbles from tissue without requiring nonlinearities. Data-driven spatiotemporal filtering operations are used to separate different features in the image on the basis of coherence both in space and time. Such filter recently proved to improve Doppler sensitivity (Demene et al 2015 IEEE Trans. Med. Imaging 34 2271-85). In contrast with bubbles, even slow moving ones, tissues are highly coherent both in space and time. Therefore, singular value decomposition (SVD) seems to be a powerful tool for the separation of contrast agents and tissues. In this paper, we apply SVD processing to linear ultrafast ultrasound images for CEUS Doppler. The contrast levels reached by this technique were compared to those of a nonlinear gold standard sequence (PMPI Doppler) through a flow phantom study. The SVD technique reached contrast-to-tissue ratios (CTR) up to 10 dB higher in vitro, and proved to be robust in terms of probe motion and slow flow. A trial was also conducted on a transplanted human kidney, already imaged by means of power Doppler (Claudon et al 1999 Am. J. Roentgenol. 173 41-6) and microbubbles (Kay et al 2009 Clin. Radiol. 64 1081-7). Contrast levels yielded by the SVD technique measured up to 13 dB higher than those of PMPI Doppler.

  8. Contrast-enhanced endoscopic ultrasonography in digestive diseases.

    PubMed

    Hirooka, Yoshiki; Itoh, Akihiro; Kawashima, Hiroki; Ohno, Eizaburo; Itoh, Yuya; Nakamura, Yosuke; Hiramatsu, Takeshi; Sugimoto, Hiroyuki; Sumi, Hajime; Hayashi, Daijiro; Ohmiya, Naoki; Miyahara, Ryoji; Nakamura, Masanao; Funasaka, Kohei; Ishigami, Masatoshi; Katano, Yoshiaki; Goto, Hidemi

    2012-10-01

    Contrast-enhanced endoscopic ultrasonography (CE-EUS) was introduced in the early 1990s. The concept of the injection of carbon dioxide microbubbles into the hepatic artery as a contrast material (enhanced ultrasonography) led to "endoscopic ultrasonographic angiography". After the arrival of the first-generation contrast agent, high-frequency (12 MHz) EUS brought about the enhancement of EUS images in the diagnosis of pancreatico-biliary diseases, upper gastrointestinal (GI) cancer, and submucosal tumors. The electronic scanning endosonoscope with both radial and linear probes enabled the use of high-end ultrasound machines and depicted the enhancement of both color/power Doppler flow-based imaging and harmonic-based imaging using second-generation contrast agents. Many reports have described the usefulness of the differential diagnosis of pancreatic diseases and other abdominal lesions. Quantitative evaluation of CE-EUS images was an objective method of diagnosis using the time-intensity curve (TIC), but it was limited to the region of interest. Recently developed Inflow Time Mapping™ can be generated from stored clips and used to display the pattern of signal enhancement with time after injection, offering temporal difference of contrast agents and improved tumor characterization. On the other hand, three-dimensional CE-EUS images added new information to the literature, but lacked positional information. Three-dimensional CE-EUS with accurate positional information is awaited. To date, most reports have been related to pancreatic lesions or lymph nodes. Hemodynamic analysis might be of use for diseases in other organs: upper GI cancer diagnosis, submucosal tumors, and biliary disorders, and it might also provide functional information. Studies of CE-EUS in diseases in many other organs will increase in the near future.

  9. Power Doppler ultrasound phenotyping of expanding versus collapsed popliteal lymph nodes in murine inflammatory arthritis.

    PubMed

    Bouta, Echoe M; Ju, Yawen; Rahimi, Homaira; de Mesy-Bentley, Karen L; Wood, Ronald W; Xing, Lianping; Schwarz, Edward M

    2013-01-01

    Rheumatoid arthritis is a chronic inflammatory disease manifested by episodic flares in affected joints that are challenging to predict and treat. Longitudinal contrast enhanced-MRI (CE-MRI) of inflammatory arthritis in tumor necrosis factor-transgenic (TNF-Tg) mice has demonstrated that popliteal lymph nodes (PLN) increase in volume and contrast enhancement during the pre-arthritic "expanding" phase of the disease, and then suddenly "collapse" during knee flare. Given the potential of this biomarker of arthritic flare, we aimed to develop a more cost-effective means of phenotyping PLN using ultrasound (US) imaging. Initially we attempted to recapitulate CE-MRI of PLN with subcutaneous footpad injection of US microbubbles (DEFINITY®). While this approach allowed for phenotyping via quantification of lymphatic sinuses in PLN, which showed a dramatic decrease in collapsed PLN versus expanding or wild-type (WT) PLN, electron microscopy demonstrated that DEFINITY® injection also resulted in destruction of the lymphatic vessels afferent to the PLN. In contrast, Power Doppler (PD) US is innocuous to and efficiently quantifies blood flow within PLN of WT and TNF-Tg mice. PD-US demonstrated that expanding PLN have a significantly higher normalized PD volume (NPDV) versus collapsed PLN (0.553 ± 0.007 vs. 0.008 ± 0.003; p<0.05). Moreover, we define the upper (>0.030) and lower (<0.016) quartile NPDVs in this cohort of mice, which serve as conservative thresholds to phenotype PLN as expanding and collapsed, respectively. Interestingly, of the 12 PLN phenotyped by the two methods, there was disagreement in 4 cases in which they were determined to be expanding by CE-MRI and collapsed by PD-US. Since the adjacent knee had evidence of synovitis in all 4 cases, we concluded that the PD-US phenotyping was correct, and that this approach is currently the safest and most cost-effective in vivo approach to phenotype murine PLN as a biomarker of arthritic flare.

  10. Contrast-Enhanced Image of Bellicia Crater

    NASA Image and Video Library

    2013-11-06

    In this contrast-enhanced infrared image of Bellicia Crater on the giant asteroid Vesta, scientists from NASA Dawn mission can see signs of the mineral olivine. Olivine was not expected to be found at Bellicia.

  11. Assessment of subclinical atherosclerosis using contrast-enhanced ultrasound.

    PubMed

    van den Oord, Stijn C H; ten Kate, Gerrit L; Akkus, Zeynettin; Renaud, Guillaume; Sijbrands, Eric J G; ten Cate, Folkert J; van der Lugt, Aad; Bosch, Johan G; de Jong, Nico; van der Steen, Antonius F W; Schinkel, Arend F L

    2013-01-01

    The sensitivity of standard carotid ultrasound and colour Doppler for the detection of subclinical atherosclerotic plaques is suboptimal. The aim of this study is to assess whether contrast-enhanced ultrasound (CEUS) added to standard carotid ultrasound improves the detection of subclinical atherosclerosis. Carotid intima-media thickness (CIMT) measurement, standard carotid ultrasound including colour Doppler imaging, and CEUS were performed in 100 asymptomatic patients with one or more risk factors for atherosclerosis. CEUS was performed using intravenous administration of SonoVue™ contrast agent (Bracco S.p.A., Milan, Italy). CIMT, standard ultrasound, colour Doppler, and CEUS were reviewed by two independent observers. Standard ultrasound, colour Doppler, and CEUS were scored for the presence of atherosclerotic plaques. Subclinical atherosclerosis was diagnosed if patients had a CIMT above their age-corrected threshold value or if atherosclerotic plaques were present on standard carotid ultrasound clips or CEUS clips. McNemar's test was performed to compare between groups. Twenty-one patients (21%) had a thickened CIMT value and were considered to have subclinical atherosclerosis. Standard carotid ultrasound including colour Doppler demonstrated atherosclerotic plaques in 77 patients (77%). The addition of CEUS to the standard ultrasound protocol demonstrated atherosclerotic plaques in 88 patients (88%). The incorporation of CEUS into the standard carotid ultrasound protocol resulted in a significantly improved detection of patients with subclinical atherosclerosis (P < 0.01). CEUS has an incremental value for the detection of subclinical atherosclerosis in the carotid arteries. Atherosclerotic plaques which were only detected with CEUS and not with standard carotid ultrasound and colour Doppler imaging were predominantly hypoechoic.

  12. Short-Term Wind Power Forecasts using Doppler Lidar

    NASA Astrophysics Data System (ADS)

    Magerman, Beth

    With a ground-based Doppler lidar on the upwind side of a wind farm in the Tehachapi Pass of California, radial wind velocity measurements were collected for repeating sector sweeps, scanning up to 10 kilometers away. This region consisted of complex terrain, with the scans made between mountains. The dataset was utilized for techniques being studied for short-term forecasting of wind power by correlating changes in energy content and of turbulence intensity by tracking spatial variance, in the wind ahead of a wind farm. A ramp event was also captured and its propagation was tracked. Orthogonal horizontal wind vectors were retrieved from the radial velocity using a sector Velocity Azimuth Display method. Streamlines were plotted to determine the potential sites for a correlation of upstream wind speed with wind speed at downstream locations near the wind farm. A "virtual wind turbine" was "placed" in locations along the streamline by using the time-series velocity data at the location as the input to a modeled wind turbine, to determine the extractable energy content at that location. The relationship between this time-dependent energy content upstream and near the wind farm was studied. By correlating the energy content with each upstream location based on a time shift estimated according to advection at the mean wind speed, several fits were evaluated. A prediction of the downstream energy content was produced by shifting the power output in time and applying the best-fit function. This method made predictions of the power near the wind farm several minutes in advance. Predictions were also made up to an hour in advance for a large ramp event. The Magnitude Absolute Error and Standard Deviation are presented for the predictions based on each selected upstream location.

  13. Dual-energy contrast-enhanced mammography.

    PubMed

    Travieso Aja, M M; Rodríguez Rodríguez, M; Alayón Hernández, S; Vega Benítez, V; Luzardo, O P

    2014-01-01

    The degree of vascularization in breast lesions is related to their malignancy. For this reason, functional diagnostic imaging techniques have become important in recent years. Dual-energy contrast-enhanced mammography is a new, apparently promising technique in breast cancer that provides information about the degree of vascularization of the lesion in addition to the morphological information provided by conventional mammography. This article describes the state of the art for dual-energy contrast-enhanced mammography. Based on 15 months' clinical experience, we illustrate this review with clinical cases that allow us to discuss the advantages and limitations of this technique.

  14. Power Doppler ultrasonography in the diagnosis of acute childhood pyelonephritis.

    PubMed

    Halevy, Raphael; Smolkin, Vladislav; Bykov, Sergey; Chervinsky, Leonid; Sakran, Waheeb; Koren, Ariel

    2004-09-01

    In the absence of specific symptomatology in children, the early diagnosis of acute pyelonephritis (APN) is a challenge, particularly during infancy. In an attempt to differentiate APN from lower urinary tract infection (UTI), we evaluated the ability of power Doppler ultrasonography (PDU) to predict renal parenchymal involvement, as assessed by dimercaptosuccinic acid ((99m )Tc-DMSA) scintigraphy. The study comprised 62 patients, 46 girls and 16 boys, aged 2 weeks to 5 years, admitted to the pediatric department with febrile UTI. All children were examined by PDU and DMSA scintigraphy within the first 3 days of admission. In the group of 31 patients with one or more DMSA scan abnormalities, the PDU showed a matching perfusion defect in 27 (87%). Of 26 children with normal DMSA scintigraphy, the PDU evaluation was also normal in 24. The sensitivity and specificity of PDU for the detection of affected kidneys were 87% and 92.3%, and the positive predictive value and negative predictive value were 93.1% and 85.7%, respectively. These data indicate the PDU has a high sensitivity and specificity for differentiating APN from lower UTI and may be a useful and practical tool for the diagnosis of APN in infants and children.

  15. Breast tumor angiogenesis analysis using 3D power Doppler ultrasound

    NASA Astrophysics Data System (ADS)

    Chang, Ruey-Feng; Huang, Sheng-Fang; Lee, Yu-Hau; Chen, Dar-Ren; Moon, Woo Kyung

    2006-03-01

    Angiogenesis is the process that correlates to tumor growth, invasion, and metastasis. Breast cancer angiogenesis has been the most extensively studied and now serves as a paradigm for understanding the biology of angiogenesis and its effects on tumor outcome and patient prognosis. Most studies on characterization of angiogenesis focus on pixel/voxel counts more than morphological analysis. Nevertheless, in cancer, the blood flow is greatly affected by the morphological changes, such as the number of vessels, branching pattern, length, and diameter. This paper presents a computer-aided diagnostic (CAD) system that can quantify vascular morphology using 3-D power Doppler ultrasound (US) on breast tumors. We propose a scheme to extract the morphological information from angiography and to relate them to tumor diagnosis outcome. At first, a 3-D thinning algorithm helps narrow down the vessels into their skeletons. The measurements of vascular morphology significantly rely on the traversing of the vascular trees produced from skeletons. Our study of 3-D assessment of vascular morphological features regards vessel count, length, bifurcation, and diameter of vessels. Investigations into 221 solid breast tumors including 110 benign and 111 malignant cases, the p values using the Student's t-test for all features are less than 0.05 indicating that the proposed features are deemed statistically significant. Our scheme focuses on the vascular architecture without involving the technique of tumor segmentation. The results show that the proposed method is feasible, and have a good agreement with the diagnosis of the pathologists.

  16. Accuracy of velocity and power determination by the Doppler method

    NASA Technical Reports Server (NTRS)

    Rottger, J.

    1984-01-01

    When designing a Mesosphere-Stratosphere-Troposphere (MST) radar antenna one has to trade between the choices to optimize the effective aperture or to optimize the sidelobe suppression. An optimization of the aperture increases the sensitivity. Suppression of side-lobes by tapering attenuates undesirable signals which spoil the estimates of reflectivity and velocity. Generally, any sidelobe effects are equivalent to a broadening of the antenna beam. The return signal is due to a product of the antenna pattern with the varying atmospheric reflectivity structures. Thus, knowing the antenna pattern, it is in principle possible to find the signal spectra, which, however, may be a tedious computational and ambiguous procedure. For vertically pointing main beams the sidelobe effects are efficiently suppressed because of the aspect sensitivity. It follows that sidelobes are a minor problem for spaced antenna methods. However, they can be crucial for Doppler methods, which need off-vertical beams. If a sidelobe is pointing towards the zenith a larger power may be received from the vertical than off-vertical directions, but quantitative estimates of this effect are not yet known. To get an error estimate of sidelobe effects with an off-vertical main beam a 1-dimensional example is considered.

  17. Acute Effects of Lateral Thigh Foam Rolling on Arterial Tissue Perfusion Determined by Spectral Doppler and Power Doppler Ultrasound.

    PubMed

    Hotfiel, Thilo; Swoboda, Bernd; Krinner, Sebastian; Grim, Casper; Engelhardt, Martin; Uder, Michael; Heiss, Rafael U

    2017-04-01

    Hotfiel, T, Swoboda, B, Krinner, S, Grim, C, Engelhardt, M, Uder, M, and Heiss, R. Acute effects of lateral thigh foam rolling on arterial tissue perfusion determined by spectral Doppler and power Doppler ultrasound. J Strength Cond Res 31(4): 893-900, 2017-Foam rolling has been developed as a popular intervention in training and rehabilitation. However, evidence on its effects on the cellular and physiological level is lacking. The aim of this study was to assess the effect of foam rolling on arterial blood flow of the lateral thigh. Twenty-one healthy participants (age, 25 ± 2 years; height, 177 ± 9 cm; body weight, 74 ± 9 kg) were recruited from the medical and sports faculty. Arterial tissue perfusion was determined by spectral Doppler and power Doppler ultrasound, represented as peak flow (Vmax), time average velocity maximum (TAMx), time average velocity mean (TAMn), and resistive index (RI), and with semiquantitative grading that was assessed by 4 blindfolded investigators. Measurement values were assessed under resting conditions and twice after foam rolling exercises of the lateral thigh (0 and 30 minutes after intervention). The trochanteric region, mid portion, and distal tibial insertion of the lateral thigh were representative for data analysis. Arterial blood flow of the lateral thigh increased significantly after foam rolling exercises compared with baseline (p ≤ 0.05). We detected a relative increase in Vmax of 73.6% (0 minutes) and 52.7% (30 minutes) (p < 0.001), in TAMx of 53.2% (p < 0.001) and 38.3% (p = 0.002), and in TAMn of 84.4% (p < 0.001) and 68.2% (p < 0.001). Semiquantitative power Doppler scores at all portions revealed increased average grading of 1.96 after intervention and 2.04 after 30 minutes compared with 0.75 at baseline. Our results may contribute to the understanding of local physiological reactions to self-myofascial release.

  18. Quantitative analysis of vascular heterogeneity in breast lesions using contrast-enhanced 3-D harmonic and subharmonic ultrasound imaging.

    PubMed

    Sridharan, Anush; Eisenbrey, John R; Machado, Priscilla; Ojeda-Fournier, Haydee; Wilkes, Annina; Sevrukov, Alexander; Mattrey, Robert F; Wallace, Kirk; Chalek, Carl L; Thomenius, Kai E; Forsberg, Flemming

    2015-03-01

    Ability to visualize breast lesion vascularity and quantify the vascular heterogeneity using contrast-enhanced 3-D harmonic (HI) and subharmonic (SHI) ultrasound imaging was investigated in a clinical population. Patients (n = 134) identified with breast lesions on mammography were scanned using power Doppler imaging, contrast-enhanced 3-D HI, and 3-D SHI on a modified Logiq 9 scanner (GE Healthcare). A region of interest corresponding to ultrasound contrast agent flow was identified in 4D View (GE Medical Systems) and mapped to raw slice data to generate a map of time-intensity curves for the lesion volume. Time points corresponding to baseline, peak intensity, and washout of ultrasound contrast agent were identified and used to generate and compare vascular heterogeneity plots for malignant and benign lesions. Vascularity was observed with power Doppler imaging in 84 lesions (63 benign and 21 malignant). The 3-D HI showed flow in 8 lesions (5 benign and 3 malignant), whereas 3-D SHI visualized flow in 68 lesions (49 benign and 19 malignant). Analysis of vascular heterogeneity in the 3-D SHI volumes found benign lesions having a significant difference in vascularity between central and peripheral sections (1.71 ± 0.96 vs. 1.13 ± 0.79 dB, p < 0.001, respectively), whereas malignant lesions showed no difference (1.66 ± 1.39 vs. 1.24 ± 1.14 dB, p = 0.24), indicative of more vascular coverage. These preliminary results suggest quantitative evaluation of vascular heterogeneity in breast lesions using contrast-enhanced 3-D SHI is feasible and able to detect variations in vascularity between central and peripheral sections for benign and malignant lesions.

  19. Quantitative Analysis of Vascular Heterogeneity in Breast Lesions Using Contrast-Enhanced 3-D Harmonic and Subharmonic Ultrasound Imaging

    PubMed Central

    Sridharan, Anush; Eisenbrey, John R.; Machado, Priscilla; Ojeda-Fournier, Haydee; Wilkes, Annina; Sevrukov, Alexander; Mattrey, Robert F.; Wallace, Kirk; Chalek, Carl L.; Thomenius, Kai E.; Forsberg, Flemming

    2015-01-01

    Ability to visualize breast lesion vascularity and quantify the vascular heterogeneity using contrast-enhanced 3-D harmonic (HI) and subharmonic (SHI) ultrasound imaging was investigated in a clinical population. Patients (n = 134) identified with breast lesions on mammography were scanned using power Doppler imaging, contrast-enhanced 3-D HI, and 3-D SHI on a modified Logiq 9 scanner (GE Healthcare). A region of interest corresponding to ultrasound contrast agent flow was identified in 4D View (GE Medical Systems) and mapped to raw slice data to generate a map of time-intensity curves for the lesion volume. Time points corresponding to baseline, peak intensity, and washout of ultrasound contrast agent were identified and used to generate and compare vascular heterogeneity plots for malignant and benign lesions. Vascularity was observed with power Doppler imaging in 84 lesions (63 benign and 21 malignant). The 3-D HI showed flow in 8 lesions (5 benign and 3 malignant), whereas 3-D SHI visualized flow in 68 lesions (49 benign and 19 malignant). Analysis of vascular heterogeneity in the 3-D SHI volumes found benign lesions having a significant difference in vascularity between central and peripheral sections (1.71 ± 0.96 vs. 1.13 ± 0.79 dB, p < 0.001, respectively), whereas malignant lesions showed no difference (1.66 ± 1.39 vs. 1.24 ± 1.14 dB, p = 0.24), indicative of more vascular coverage. These preliminary results suggest quantitative evaluation of vascular heterogeneity in breast lesions using contrast-enhanced 3-D SHI is feasible and able to detect variations in vascularity between central and peripheral sections for benign and malignant lesions. PMID:25935933

  20. Screening for rheumatoid arthritis with finger joint power Doppler ultrasonography: quantification of conventional power Doppler ultrasonographic scoring.

    PubMed

    Fukae, Jun; Shimizu, Masato; Kon, Yujiro; Tanimura, Kazuhide; Matsuhashi, Megumi; Kamishima, Tamotsu; Koike, Takao

    2009-01-01

    Power Doppler ultrasonography (PD-US) has proved to be a useful technique to measure synovial vascularity due to its capability to provide data that can be used to evaluate the level of joint inflammation and assess rheumatoid arthritis (RA). We have developed a novel PD-US finger joint scoring method that introduces quantitative measurements into the conventional PD-US assessment method. A comparison of the two methods revealed that our novel PD-US method strongly correlates with the conventional method in terms of RA assessment. We performed finger joint PD-US on 69 patients with RA and 70 patients who had multiple joint pain but showed no evidence of inflammatory diseases (non-inflammatory disease, NI) and measured the synovial vascularity of the metacarpophalangeal joints 1-5 and proximal interphalangeal (PIP) joints 1-5 for each patient. We analyzed the data with receiver operating characteristic analysis and, based on the results for the total vascularity of 20 finger joints, defined a cut-off value of 36% as discriminating between RA and NI. This cut-off value was found to be a valuable tool in screening for RA. We conclude that our finger joint PD-US scoring system is both useful and applicable for diagnosing RA.

  1. Clinical evaluation of contrast-enhanced digital mammography and contrast enhanced tomosynthesis--Comparison to contrast-enhanced breast MRI.

    PubMed

    Chou, Chen-Pin; Lewin, John M; Chiang, Chia-Ling; Hung, Bao-Hui; Yang, Tsung-Lung; Huang, Jer-Shyung; Liao, Jia-Bin; Pan, Huay-Ben

    2015-12-01

    To compare the diagnostic accuracy of contrast-enhanced digital mammography (CEDM) and contrast-enhanced tomosynthesis (CET) to dynamic contrast enhanced breast MRI (DCE-MRI) using a multireader-multicase study. Institutional review board approval and informed consents were obtained. Total 185 patients (mean age 51.3) with BI-RADS 4 or 5 lesions were evaluated before biopsy with mammography, tomosynthesis, CEDM, CET and DCE-MRI. Mediolateral-oblique and cranio-caudal views of the target breast CEDM and CET were acquired at 2 and 4 min after contrast agent injection. A mediolateral-oblique view of the non-target breast was taken at 6 min. Each lesion was scored with forced BI-RADS categories by three readers. Each reader interpreted lesions in the following order: mammography, tomosynthesis, CEDM, CET, and DCE-MRI during a single reading session. Histology showed 81 cancers and 144 benign lesions in the study. Of the 81 malignant lesions, 44% (36/81) were invasive and 56% (45/81) were non-invasive. Areas under the ROC curve, averaged for the 3 readers, were as follows: 0.897 for DCE-MRI, 0.892 for CET, 0.878 for CEDM, 0.784 for tomosynthesis and 0.740 for mammography. Significant differences in AUC were found between the group of contrast enhanced modalities (CEDM, CET, DCE-MRI) and the unenhanced modalities (all p<0.05). No significant differences were found in AUC between DCE-MRI, CET and CEDM (all p>0.05). CET and CEDM may be considered as an alternative modality to MRI for following up women with abnormal mammography. All three contrast modalities were superior in accuracy to conventional digital mammography with or without tomosynthesis. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  2. The effect of foot position on Power Doppler Ultrasound grading of Achilles enthesitis.

    PubMed

    Zappia, Marcello; Cuomo, Giovanna; Martino, Maria Teresa; Reginelli, Alfonso; Brunese, Luca

    2016-06-01

    The aim of this study was to determine whether foot position could modify power Doppler grading in evaluation of the Achilles enthesis. Eighteen patients with clinical Achilles enthesitis were studied with power Doppler ultrasound (PDUS) in five different positions of the foot: active and passive dorsiflexion, neutral position, active and passive plantar flexion. The Doppler signal was graded in any position and compared with the others. The Doppler signal was higher with the foot in plantar flexion and decreased gradually, sometimes till to disappear, while increasing dorsiflexion. The Doppler signal was always less during the active keeping of the position of the joint, than during the passive. The PDUS examination of the Achilles enthesis should be performed also with the foot in passive plantar flexion, in order not to underestimate the degree of vascularization.

  3. Settings and artefacts relevant in colour/power Doppler ultrasound in rheumatology.

    PubMed

    Torp-Pedersen, S T; Terslev, L

    2008-02-01

    The paper explains the most important parameters for the use of colour and power Doppler in rheumatology. Recommendations for machine settings are given. The commonly encountered artefacts and their importance for image interpretation are explained.

  4. Adaptive overlapped sub-blocks contrast enhancement

    NASA Astrophysics Data System (ADS)

    Chen, Anqiu; Yuan, Fei; Liu, Jing; Liu, Siqi; Li, An; Zheng, Zhenrong

    2016-09-01

    In this paper, an overlapped sub-block gray-level average method for contrast enhancement is presented. The digital image correction of uneven illumination under microscope transmittance is a problem in image processing, also sometimes the image in the dark place need to correct the uneven problem. A new correction method was proposed based on the mask method and sub-blocks gray-level average method because Traditional mask method and background fitting method are restricted due to application scenarios, and the corrected image brightness is low by using background fitting method, so it has some limitations of the application. In this paper, we introduce a new method called AOSCE for image contrast enhancement. The image is divided into many sub-blocks which are overlapped, calculate the average gray-level of the whole image as M and the calculate the average gray-level of each one as mi, next for each block it can get d = mi - m, each block minus d to get a new image, and then get the minimum gray-level of each block into a matrix DD to get the background, and use bilinearity to get the same scale of the image. over fitting the image in matlab in order to get smoother image, then minus the background to get the contrast enhancement image.

  5. Low-frequency high-definition power Doppler in visualizing and defining fetal pulmonary venous connections.

    PubMed

    Liu, Lin; He, Yihua; Li, Zhian; Gu, Xiaoyan; Zhang, Ye; Zhang, Lianzhong

    2014-07-01

    The use of low-frequency high-definition power Doppler in assessing and defining pulmonary venous connections was investigated. Study A included 260 fetuses at gestational ages ranging from 18 to 36 weeks. Pulmonary veins were assessed by performing two-dimensional B-mode imaging, color Doppler flow imaging (CDFI), and low-frequency high-definition power Doppler. A score of 1 was assigned if one pulmonary vein was visualized, 2 if two pulmonary veins were visualized, 3 if three pulmonary veins were visualized, and 4 if four pulmonary veins were visualized. The detection rate between Exam-1 and Exam-2 (intra-observer variability) and between Exam-1 and Exam-3 (inter-observer variability) was compared. In study B, five cases with abnormal pulmonary venous connection were diagnosed and compared to their anatomical examination. In study A, there was a significant difference between CDFI and low-frequency high-definition power Doppler for the four pulmonary veins observed (P < 0.05). The detection rate of each pulmonary vein when employing low-frequency high-definition power Doppler was higher than that when employing two-dimensional B-mode imaging or CDFI. There was no significant difference between the intra- and inter-observer variabilities using low-frequency high-definition power Doppler display of pulmonary veins (P > 0.05). The coefficient correlation between Exam-1 and Exam-2 was 0.844, and the coefficient correlation between Exam-1 and Exam-3 was 0.821. In study B, one case of total anomalous pulmonary venous return and four cases of partial anomalous pulmonary venous return were diagnosed by low-frequency high-definition power Doppler and confirmed by autopsy. The assessment of pulmonary venous connections by low-frequency high-definition power Doppler is advantageous. Pulmonary venous anatomy can and should be monitored during fetal heart examination.

  6. Doppler spectroscopy, a powerful tool for studying molecular collision dynamics

    SciTech Connect

    Mestdagh, J.M.; Visticot, J.P.

    1994-12-31

    The present review describes the application of Doppler spectroscopy to studies in collision dynamics. The method was originally introduced by Kinsey (J. Chem. Phys. 66, 2560 (1976)). The authors used it to obtain angular and velocity distributions of Ba(6s6p{sup 1}P{sub 1}) atoms scattered in the 6s6p{sup 3}P{sub 2} level by collisions with argon and simple molecules. After a short review of their recent work, the authors outline those areas where Doppler spectroscopy is a valuable tool (sometimes the only tool) for exploring gas phase collision dynamics. In particular they make clear that Doppler spectroscopy should not be considered as alternative but rather as complementary to the standard way of measuring differential cross sections where a rotating mass spectrometer rather than laser induced fluorescence is used to detect the scattered particles.

  7. Contrast-enhanced B-mode US angiography in the assessment of experimental in vivo and in vitro atherosclerotic disease.

    PubMed

    Sirlin, C B; Lee, Y Z; Girard, M S; Peterson, T M; Steinbach, G C; Baker, K G; Mattrey, R F

    2001-02-01

    This study was performed to (a) test the hypothesis that filling the arterial lumen with echoes at B-mode ultrasound (US) enables the assessment of wall and luminal abnormalities and (b) compare contrast material-enhanced B-mode US with color and power Doppler US angiography. Atherosclerotic lesions were created in 14 rabbit aortas and imaged with color Doppler and B-mode US before and after the intravenous administration of 0.3 mL of AF0150, a US contrast agent. In addition, four replicas of diseased human carotid arteries were immersed in a tissue-mimicking phantom and imaged with B-mode and color and power Doppler US before and after the administration of 1 mL of AF0150 per liter of porcine blood. Radiopaque plastic casts of the rabbit aortas and contact radiographs of the plastic replicas served as standards. Although color and power Doppler US allowed immediate localization of the lumen, precise estimation of stenoses and reliable visualization of surface irregularities were not possible. After AF0150 administration, angiogram-like images of the lumen were created with B-mode US, allowing rapid assessment of the entire vessel lumen and wall. Consequently, luminal stenoses were more accurately measured than with unenhanced B-mode US (r2 = 0.94, P < .0001 vs r2 = 0.21, P = .25) or Doppler (r2 = 0.42, P < .03). In addition, plaques and ulcerations were visible only with contrast-enhanced B-mode US. Microbubbles fill the arterial lumen with echoes at B-mode US, creating an angiogram-like image. The ability to visualize the inner and outer surfaces of the vascular wall improved the evaluation of luminal and wall abnormalities.

  8. Color and power Doppler combined with Fetal Intelligent Navigation Echocardiography (FINE) to evaluate the fetal heart.

    PubMed

    Yeo, L; Romero, R

    2017-08-14

    To evaluate the performance of color and bidirectional power Doppler ultrasound combined with Fetal Intelligent Navigation Echocardiography (FINE) in examining the fetal heart. A prospective cohort study was conducted of fetuses in the second and third trimesters with a normal heart or with congenital heart disease (CHD). One or more spatiotemporal image correlation (STIC) volume datasets, combined with color or bidirectional power Doppler (S-flow) imaging, were acquired in the apical four-chamber view. Each successfully obtained STIC volume was evaluated by STICLoop™ to determine its appropriateness before applying the FINE method. Visualization rates for standard fetal echocardiography views using diagnostic planes and/or Virtual Intelligent Sonographer Assistance (VIS-Assistance®) were calculated for grayscale (removal of Doppler signal), color Doppler and S-flow Doppler. In four cases with CHD (one case each of tetralogy of Fallot, hypoplastic left heart and coarctation of the aorta, interrupted inferior vena cava with azygos vein continuation and asplenia, and coarctation of the aorta with tricuspid regurgitation and hydrops), the diagnostic potential of this new technology was presented. A total of 169 STIC volume datasets of the normal fetal heart (color Doppler, n = 78; S-flow Doppler, n = 91) were obtained from 37 patients. Only a single STIC volume of color Doppler and/or a single volume of S-flow Doppler per patient were analyzed using FINE. Therefore, 60 STIC volumes (color Doppler, n = 27; S-flow Doppler, n = 33) comprised the final study group. Median gestational age at sonographic examination was 23 (interquartile range, 21-27.5) weeks. Color Doppler FINE generated nine fetal echocardiography views (grayscale) using (1) diagnostic planes in 73-100% of cases, (2) VIS-Assistance in 100% of cases, and (3) a combination of diagnostic planes and/or VIS-Assistance in 100% of cases. The rate of generating successfully eight fetal echocardiography views

  9. Laser backscattering analytical model of Doppler power spectra about rotating convex quadric bodies of revolution

    NASA Astrophysics Data System (ADS)

    Gong, YanJun; Wu, ZhenSen; Wang, MingJun; Cao, YunHua

    2010-01-01

    We propose an analytical model of Doppler power spectra in backscatter from arbitrary rough convex quadric bodies of revolution (whose lateral surface is a quadric) rotating around axes. In the global Cartesian coordinate system, the analytical model deduced is suitable for general convex quadric body of revolution. Based on this analytical model, the Doppler power spectra of cones, cylinders, paraboloids of revolution, and sphere-cones combination are proposed. We analyze numerically the influence of geometric parameters, aspect angle, wavelength and reflectance of rough surface of the objects on the broadened spectra because of the Doppler effect. This analytical solution may contribute to laser Doppler velocimetry, and remote sensing of ballistic missile that spin.

  10. Contrast enhanced ultrasound of breast cancer

    PubMed Central

    Cassano, E; Rizzo, S; Bozzini, A; Menna, S; Bellomi, M

    2006-01-01

    The importance of ultrasound examination in the diagnosis of breast cancer has been widely demonstrated. During the last few years, the introduction of ultrasound contrast media has been considered a promising tool for studying the vascular pattern of focal lesions within the breast. Our purpose was to assess whether contrast-enhanced (CE) ultrasound examination, performed using specific contrast imaging modes, can be helpful for detection and characterization of breast lesions, and for prediction of the response of breast cancer to therapy. PMID:16478698

  11. Contrast enhanced ultrasound of sentinel lymph nodes.

    PubMed

    Cui, XinWu; Ignee, Andre; Nielsen, Michael Bachmann; Schreiber-Dietrich, Dagmar; De Molo, Chiara; Pirri, Clara; Jedrzejczyk, Maciej; Christoph, Dietrich F

    2013-03-01

    Sentinel lymph nodes are the first lymph nodes in the region that receive lymphatic drainage from a primary tumor. The detection or exclusion of sentinel lymph node micrometastases is critical in the staging of cancer, especially breast cancer and melanoma because it directly affects patient's prognosis and surgical management. Currently, intraoperative sentinel lymph node biopsies using blue dye and radioisotopes are the method of choice for the detection of sentinel lymph node with high identification rate. In contrast, conventional ultrasound is not capable of detecting sentinel lymph nodes in most cases. Contrast enhanced ultrasound with contrast specific imaging modes has been used for the evaluation and diagnostic work-up of peripherally located suspected lymphadenopathy. The method allows for real-time analysis of all vascular phases and the visualization of intranodal focal "avascular" areas that represent necrosis or deposits of neoplastic cells. In recent years, a number of animal and human studies showed that contrast enhanced ultrasound can be also used for the detection of sentinel lymph node, and may become a potential application in clinical routine. Several contrast agents have been used in those studies, including albumin solution, hydroxyethylated starch, SonoVue(®), Sonazoid(®) and Definity(®). This review summarizes the current knowledge about the use of ultrasound techniques in detection and evaluation of sentinel lymph node.

  12. Fast contrast enhanced imaging with projection reconstruction

    NASA Astrophysics Data System (ADS)

    Peters, Dana Ceceilia

    The use of contrast agents has lead to great advances in magnetic resonance angiography (MRA). Here we present the first application of projection reconstruction to contrast enhanced MRA. In this research the limited angle projection reconstruction (PR) trajectory is implemented to acquire higher resolution images per unit time than with conventional Fourier transform (FT) imaging. It is well known that as FOV is reduced in conventional spin- warp imaging, higher resolution per unit time can be obtained, but aliasing may appear as a replication of outside material within the FOV. The limited angle PR acquisition also produces aliasing artifacts. This method produced artifacts which were unacceptable in X-ray CT but which appear to be tolerable in MR Angiography. Resolution throughout the FOV is determined by the projection readout resolution and not by the number of projections. As the number of projections is reduced, the resolution is unchanged, but low intensity artifacts appear. Here are presented the results of using limited angle PR in phantoms and contrast-enhanced angiograms of humans.

  13. Quantitative contrast-enhanced optical coherence tomography

    PubMed Central

    Winetraub, Yonatan; SoRelle, Elliott D.; Liba, Orly; de la Zerda, Adam

    2016-01-01

    We have developed a model to accurately quantify the signals produced by exogenous scattering agents used for contrast-enhanced Optical Coherence Tomography (OCT). This model predicts distinct concentration-dependent signal trends that arise from the underlying physics of OCT detection. Accordingly, we show that real scattering particles can be described as simplified ideal scatterers with modified scattering intensity and concentration. The relation between OCT signal and particle concentration is approximately linear at concentrations lower than 0.8 particle per imaging voxel. However, at higher concentrations, interference effects cause signal to increase with a square root dependence on the number of particles within a voxel. Finally, high particle concentrations cause enough light attenuation to saturate the detected signal. Predictions were validated by comparison with measured OCT signals from gold nanorods (GNRs) prepared in water at concentrations ranging over five orders of magnitude (50 fM to 5 nM). In addition, we validated that our model accurately predicts the signal responses of GNRs in highly heterogeneous scattering environments including whole blood and living animals. By enabling particle quantification, this work provides a valuable tool for current and future contrast-enhanced in vivo OCT studies. More generally, the model described herein may inform the interpretation of detected signals in modalities that rely on coherence-based detection or are susceptible to interference effects. PMID:26869724

  14. Optimization of subcutaneous vein contrast enhancement

    NASA Astrophysics Data System (ADS)

    Zeman, Herbert D.; Lovhoiden, Gunnar; Deshmukh, Harshal

    2000-05-01

    A technique for enhancing the contrast of subcutaneous veins has been demonstrated. This techniques uses a near IR light source and one or more IR sensitive CCD TV cameras to produce a contrast enhanced image of the subcutaneous veins. This video image of the veins is projected back onto the patient's skin using a n LCD video projector. The use of an IR transmitting filter in front of the video cameras prevents any positive feedback from the visible light from the video projector from causing instabilities in the projected image. The demonstration contrast enhancing illuminator has been tested on adults and children, both Caucasian and African-American, and it enhances veins quite well in all cases. The most difficult cases are those where significant deposits of subcutaneous fat are present which make the veins invisible under normal room illumination. Recent attempts to see through fat using different IR wavelength bands and both linearly and circularly polarized light were unsuccessful. The key to seeing through fat turns out to be a very diffuse source of RI light. Results on adult and pediatric subjects are shown with this new IR light source.

  15. Quantitative contrast-enhanced optical coherence tomography

    SciTech Connect

    Winetraub, Yonatan; SoRelle, Elliott D.; Liba, Orly; Zerda, Adam de la

    2016-01-11

    We have developed a model to accurately quantify the signals produced by exogenous scattering agents used for contrast-enhanced Optical Coherence Tomography (OCT). This model predicts distinct concentration-dependent signal trends that arise from the underlying physics of OCT detection. Accordingly, we show that real scattering particles can be described as simplified ideal scatterers with modified scattering intensity and concentration. The relation between OCT signal and particle concentration is approximately linear at concentrations lower than 0.8 particle per imaging voxel. However, at higher concentrations, interference effects cause signal to increase with a square root dependence on the number of particles within a voxel. Finally, high particle concentrations cause enough light attenuation to saturate the detected signal. Predictions were validated by comparison with measured OCT signals from gold nanorods (GNRs) prepared in water at concentrations ranging over five orders of magnitude (50 fM to 5 nM). In addition, we validated that our model accurately predicts the signal responses of GNRs in highly heterogeneous scattering environments including whole blood and living animals. By enabling particle quantification, this work provides a valuable tool for current and future contrast-enhanced in vivo OCT studies. More generally, the model described herein may inform the interpretation of detected signals in modalities that rely on coherence-based detection or are susceptible to interference effects.

  16. MRI contrast enhancement using Magnetic Carbon Nanoparticles

    NASA Astrophysics Data System (ADS)

    Chaudhary, Rakesh P.; Kangasniemi, Kim; Takahashi, Masaya; Mohanty, Samarendra K.; Koymen, Ali R.; Department of Physics, University of Texas at Arlington Team; University of Texas Southwestern Medical Center Team

    2014-03-01

    In recent years, nanotechnology has become one of the most exciting forefront fields in cancer diagnosis and therapeutics such as drug delivery, thermal therapy and detection of cancer. Here, we report development of core (Fe)-shell (carbon) nanoparticles with enhanced magnetic properties for contrast enhancement in MRI imaging. These new classes of magnetic carbon nanoparticles (MCNPs) are synthesized using a bottom-up approach in various organic solvents, using the electric plasma discharge generated in the cavitation field of an ultrasonic horn. Gradient echo MRI images of well-dispersed MCNP-solutions (in tube) were acquired. For T2 measurements, a multi echo spin echo sequence was performed. From the slope of the 1/T2 versus concentration plot, the R2 value for different CMCNP-samples was measured. Since MCNPs were found to be extremely non-reactive, and highly absorbing in NIR regime, development of carbon-based MRI contrast enhancement will allow its simultaneous use in biomedical applications. We aim to localize the MCNPs in targeted tissue regions by external DC magnetic field, followed by MRI imaging and subsequent photothermal therapy.

  17. Quantitative contrast-enhanced optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Winetraub, Yonatan; SoRelle, Elliott D.; Liba, Orly; de la Zerda, Adam

    2016-01-01

    We have developed a model to accurately quantify the signals produced by exogenous scattering agents used for contrast-enhanced Optical Coherence Tomography (OCT). This model predicts distinct concentration-dependent signal trends that arise from the underlying physics of OCT detection. Accordingly, we show that real scattering particles can be described as simplified ideal scatterers with modified scattering intensity and concentration. The relation between OCT signal and particle concentration is approximately linear at concentrations lower than 0.8 particle per imaging voxel. However, at higher concentrations, interference effects cause signal to increase with a square root dependence on the number of particles within a voxel. Finally, high particle concentrations cause enough light attenuation to saturate the detected signal. Predictions were validated by comparison with measured OCT signals from gold nanorods (GNRs) prepared in water at concentrations ranging over five orders of magnitude (50 fM to 5 nM). In addition, we validated that our model accurately predicts the signal responses of GNRs in highly heterogeneous scattering environments including whole blood and living animals. By enabling particle quantification, this work provides a valuable tool for current and future contrast-enhanced in vivo OCT studies. More generally, the model described herein may inform the interpretation of detected signals in modalities that rely on coherence-based detection or are susceptible to interference effects.

  18. Doppler lidar power, aperture diameter, and FFT size trade-off study

    NASA Astrophysics Data System (ADS)

    Chester, David B.; Budge, Scott E.

    2017-05-01

    In the design or selection of a Doppler lidar instrument for a spacecraft landing system, it is important to evaluate the balance between performance requirements and cost, weight, and power consumption. Leveraging the capability of LadarSIM, a trade-off study was performed to evaluate the interaction between the laser transmission power, aperture diameter, and FFT size in a Doppler lidar system. For this study the probabilities of detection and false alarm were calculated using LadarSIM to simulate FMCW lidar systems with varying power, aperture diameter, and FFT size. This paper reports the results of this trade-off study.

  19. Contrast-enhanced ultrasound (CEUS) in nephrology: Has the time come for its widespread use?

    PubMed

    Granata, Antonio; Zanoli, Luca; Insalaco, Monica; Valentino, Massimo; Pavlica, Pietro; Di Nicolò, Pier Paolo; Scuderi, Mario; Fiorini, Fulvio; Fatuzzo, Pasquale; Bertolotto, Michele

    2015-08-01

    Grey-scale ultrasound has an important diagnostic role in nephrology. The absence of ionizing radiations and nephrotoxicity, rapidity of execution, excellent repeatability, the possibility to perform the test at the patient's bed and the low cost represent important advantages of this technique. Paired with real-time sonography and colour-power-Doppler contrast-enhanced ultrasound (CEUS) reduces the diagnostic gap with computed tomography (CT) and magnetic resonance (MR) and represents a major step in the evolution of clinical ultrasound. Although there are several situations in which contrast-enhanced CT and MR are indicated (i.e. evaluation of cystic or ischemic lesions, traumatisms and ablative therapies of the native and transplanted kidney), the use of CT contrast media presents a high risk of contrast-induced nephropathy (i.e. in elderly people, subjects with comorbidities and those with renal dysfunction), while gadolinium-based RM contrast agents are contraindicated for the risk of nephrogenic systemic fibrosis (i.e. in patients with severe renal dysfunction). In these situations, CEUS may be a viable alternative, however, as any technique associated with the infusion of pharmacological substances, the potential advantages and risks of CEUS should be critically evaluated. In this regard, the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) has published the guidelines for the use of CEUS for the kidney imaging and the International Contrast Ultrasound Society (ICUS) has been recently founded. The aim of this review is to offer an updated overview of the potential applications of CEUS in nephrology, reporting some indications and possible risks associated to its use.

  20. Power and color Doppler ultrasound settings for inflammatory flow: impact on scoring of disease activity in patients with rheumatoid arthritis.

    PubMed

    Torp-Pedersen, Søren; Christensen, Robin; Szkudlarek, Marcin; Ellegaard, Karen; D'Agostino, Maria Antonietta; Iagnocco, Annamaria; Naredo, Esperanza; Balint, Peter; Wakefield, Richard J; Torp-Pedersen, Arendse; Terslev, Lene

    2015-02-01

    To determine how settings for power and color Doppler ultrasound sensitivity vary on different high- and intermediate-range ultrasound machines and to evaluate the impact of these changes on Doppler scoring of inflamed joints. Six different types of ultrasound machines were used. On each machine, the factory setting for superficial musculoskeletal scanning was used unchanged for both color and power Doppler modalities. The settings were then adjusted for increased Doppler sensitivity, and these settings were designated study settings. Eleven patients with rheumatoid arthritis (RA) with wrist involvement were scanned on the 6 machines, each with 4 settings, generating 264 Doppler images for scoring and color quantification. Doppler sensitivity was measured with a quantitative assessment of Doppler activity: color fraction. Higher color fraction indicated higher sensitivity. Power Doppler was more sensitive on half of the machines, whereas color Doppler was more sensitive on the other half, using both factory settings and study settings. There was an average increase in Doppler sensitivity, despite modality, of 78% when study settings were applied. Over the 6 machines, 2 Doppler modalities, and 2 settings, the grades for each of 7 of the patients varied between 0 and 3, while the grades for each of the other 4 patients varied between 0 and 2. The effect of using different machines, Doppler modalities, and settings has a considerable influence on the quantification of inflammation by ultrasound in RA patients, and this must be taken into account in multicenter studies. Copyright © 2015 by the American College of Rheumatology.

  1. Coherent Flow Power Doppler (CFPD): Flow Detection using Spatial Coherence Beamforming

    PubMed Central

    Li, You Leo; Dahl, Jeremy J.

    2015-01-01

    Power Doppler imaging is a widely used method of flow detection for tissue perfusion monitoring, inflammatory hyperemia detection, deep vein thrombosis diagnosis, and other clinical applications. However, thermal noise and clutter limit its sensitivity and ability to detect slow flow. In addition, large ensembles are required to obtain sufficient sensitivity, which limits frame rate and yields flash artifacts during moderate tissue motion. We propose an alternative method of flow detection using the spatial coherence of backscattered ultrasound echoes. The method enhances slow flow detection and frame rate, while maintaining or improving the signal quality of conventional power Doppler techniques. The feasibility of this method is demonstrated with simulations, flow-phantom experiments, and an in-vivo human thyroid study. In comparison to conventional power Doppler imaging, the proposed method can produce Doppler images with 15-30 dB SNR improvement. Therefore, it is able to detect flow with velocities approximately 50% lower than conventional power Doppler, or improve the frame rate by a factor of 3 with comparable image quality. The results show promise for clinical applications of the method. PMID:26067037

  2. Contrast-Enhanced Digital Mammography and Angiogenesis

    SciTech Connect

    Rosado-Mendez, I.; Palma, B. A.; Villasenor, Y.; Benitez-Bribiesca, L.; Brandan, M. E.

    2007-11-26

    Angiogenesis could be a means for pouring contrast media around tumors. In this work, optimization of radiological parameters for contrast-enhanced subtraction techniques in mammography has been performed. A modification of Lemacks' analytical formalism was implemented to model the X-ray absorption in the breast with contrast medium and detection by a digital image receptor. Preliminary results of signal-to-noise ratio analysis show the advantage of subtracting two images taken at different energies, one prior and one posterior to the injection of contrast medium. Preliminary experimental results using a custom-made phantom have shown good agreement with calculations. A proposal is presented for the clinical application of the optimized technique, which aims at finding correlations between angiogenesis indicators and dynamic variables of contrast medium uptake.

  3. Role of 3D power Doppler sonography in early prenatal diagnosis of Galen vein aneurysm

    PubMed Central

    Ergenoğlu, Mete Ahmet; Yeniel, Ahmet Özgür; Akdemir, Ali; Akercan, Fuat; Karadadaş, Nedim

    2013-01-01

    Vein of Galen aneurysm malformation (VGAM) is a rare congenital vascular anomaly. Although the cause of VGAM remains to be elucidated, the current hypothesis is persistence of the embryonic vascular supply, which leads to progressive enlargement and formation of the aneurysmal component of a typical VGAM. Here, we present a 36-year-old woman at 23 weeks’ gestation (gravida 3, para 2) who was evaluated using 3D power Doppler sonography for the prenatal diagnosis of a vein of Galen aneurysm. Investigation using 3D power Doppler sonography allowed for a non-invasive yet diffuse and detailed prenatal assessment of VGAM. Thus, we suggest that prenatal sonography with 3D power Doppler may be an option in cases of VGAM. PMID:24592100

  4. Local adaptive contrast enhancement for color images

    NASA Astrophysics Data System (ADS)

    Dijk, Judith; den Hollander, Richard J. M.; Schavemaker, John G. M.; Schutte, Klamer

    2007-04-01

    A camera or display usually has a smaller dynamic range than the human eye. For this reason, objects that can be detected by the naked eye may not be visible in recorded images. Lighting is here an important factor; improper local lighting impairs visibility of details or even entire objects. When a human is observing a scene with different kinds of lighting, such as shadows, he will need to see details in both the dark and light parts of the scene. For grey value images such as IR imagery, algorithms have been developed in which the local contrast of the image is enhanced using local adaptive techniques. In this paper, we present how such algorithms can be adapted so that details in color images are enhanced while color information is retained. We propose to apply the contrast enhancement on color images by applying a grey value contrast enhancement algorithm to the luminance channel of the color signal. The color coordinates of the signal will remain the same. Care is taken that the saturation change is not too high. Gamut mapping is performed so that the output can be displayed on a monitor. The proposed technique can for instance be used by operators monitoring movements of people in order to detect suspicious behavior. To do this effectively, specific individuals should both be easy to recognize and track. This requires optimal local contrast, and is sometimes much helped by color when tracking a person with colored clothes. In such applications, enhanced local contrast in color images leads to more effective monitoring.

  5. Power doppler ultrasonography guided and random prostate biopsy in prostate cancer diagnosis - a comparative study.

    PubMed

    Sohail, Shahzada Khalid; Sarfraz, Rahat; Imran, Muhammad; Khan, Naeem Ahmed; Yusuf, Noshin Wasim

    2015-01-01

    To compare the diagnostic accuracy of power Doppler-guided targeted prostate biopsy and random sextant biopsy in the diagnosis of prostate cancer. The prospective study was carried out at the Allama Iqbal Medical College and Jinnah Hospital, Lahore, Pakistan, from January to December, 2012, and comprised clinically suspected cases of carcinoma prostate. Power Doppler-guided biopsies using automatic biopsy gun were obtained from the suspected targeted site. One to three cores per suspected site were obtained. Subsequently random sextant biopsies were performed in the same sitting. Six cores were obtained from 6 random sites using the same gun. Biopsies from both sources were processed for routine haematoxylin and eosin stainstained sections for histopathological examination. Of the 50 patients in the study, 30(60%) were diagnosed with power Doppler-guided biopsy as malignant, whereas random sextant biopsy could pick up 22(44%) cases. For benign prostatic hyperplasia, random sextant biopsy labelled 28(56%)as benign, whereas only 20 (40%) were labelled as benign with power Doppler-guided biopsy. Discrepancy in the results between the two procedures was observed in 14(28%) cases, and of them, 1 1(22%) were labelled as malignant on power Doppler-guided biopsy while histopathology of sextant biopsies labelled these as benign.The sextant biopsies rendered a specificity, sensitivity, negative predictive value, positive predictive value and diagnostic accuracy of 60.71%, 86.36%, 85%, 63.33% and 72% respectively. Random sextant biopsy in combination with power Doppler-guided targeted biopsy increases the rate of detection of prostate cancer whereas both procedures in isolation have low sensitivity and specificity for cancer detection.

  6. Comparison between ultrasonographic findings of benign and malignant canine mammary gland tumours using B-mode, colour Doppler, power Doppler and spectral Doppler.

    PubMed

    Soler, Marta; Dominguez, Elisabet; Lucas, Xiomara; Novellas, Rosa; Gomes-Coelho, Kassia Valeria; Espada, Yvonne; Agut, Amalia

    2016-08-01

    The aim of this study was to evaluate whether the comparison between the ultrasonographic features of canine mammary tumours, assessed by B-Mode, colour Doppler, power Doppler, spectral Doppler, and histopathologic features, would help to differentiate if a tumour is benign or malignant. Ultrasonographic examinations of 104 tumours were performed. Volume, margins, presence of a capsule, echotexture and presence and distribution of the vascular flow of the tumours were evaluated. All the tumours were surgically removed, submitted for histopathologic examination and classified in two groups: Group I (benign tumours) and Group II (malignant tumours). Echotexture was the only parameter evaluated by B-Mode ultrasonography where significant differences were found (p<0.01), with tumours in Group I being homogeneous and tumours in Group II presenting greater heterogeneity. Presence of vascular flow was observed in most of the tumours from both groups and no differences between them were found. Regarding flow distribution, significant differences were observed between groups (p<0.05). In benign tumours, the most common vascular pattern was the peripheral, showing significant differences (p<0.05) compared to mixed and central patterns. In malignant tumours the mixed pattern was the most frequent. Also significant differences among other patterns (peripheral and central) were found. Concerning vascular resistivity and pulsatility indexes, there were no significant differences between the two groups. The echotexture and type of vascular flow pattern of canine mammary gland tumours may help, in a first examination of the tumour, to differentiate between benign and malignant tumours; however to reach a definitive diagnosis histological study is required. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Role of contrast-enhanced ultrasound (CEUS) in the diagnosis of endometrial pathology

    PubMed Central

    POP, CIPRIAN MIHAITA; MIHU, DAN; BADEA, RADU

    2015-01-01

    Ultrasound is the reference imaging procedure used for the exploration of endometrial pathology. As medical procedures improve and the requirements of modern medicine become more demanding, gray-scale ultrasound is insufficient in establishing gynecological diagnosis. Thus, more complex examination techniques are required: Doppler ultrasound, contrast-enhanced ultrasound (CEUS), 3D ultrasound, etc. Contrast-enhanced ultrasound is a special examination technique that gains more and more ground. This allows a detailed real-time evaluation of microcirculation in a certain territory, which is impossible to perform by Doppler ultrasound. The aim of this review is to synthesize current knowledge regarding CEUS applications in endometrial pathology, to detail the technical aspects of endometrial CEUS and the physical properties of the equipment and contrast agents used, as well as to identify the limitations of the method. PMID:26733740

  8. Value of superb microvascular imaging ultrasonography in the diagnosis of carpal tunnel syndrome: Compared with color Doppler and power Doppler.

    PubMed

    Chen, Jie; Chen, Li; Wu, Lei; Wang, Rui; Liu, Ji-Bin; Hu, Bing; Jiang, Li-Xin

    2017-05-01

    The aim of this study was to compare the value of superb microvascular imaging (SMI) in carpal tunnel syndrome (CTS) with that of color Doppler ultrasonography (CDUS) and power Doppler ultrasonography (PDUS).Fifty patients with symptomatic CTS and 25 healthy volunteers were enrolled. The cross-sectional area (CSA), CDUS score, PDUS score, and SMI score of the median nerve (MN) at the carpal tunnel were recorded. The value of different ultrasonography (US) diagnostic strategies was calculated.The blood flow display ratio in the MN of the healthy volunteers had no statistical difference between CDUS, PDUS, and SMI (20%, 32%, and 48%, respectively, P >.05). The blood flow display ratio for SMI in patients was significantly higher than that of CDUS and PDUS (90%, 52%, and 60%, respectively, P <.005). The accuracy of SMI score ≥2 (79%) was much higher than that of CDUS and PDUS (61% and 63%, respectively, P <.05). Comprehensive consideration of SMI and CSA, CSA≥10.5 mm, and/or SMI score ≥2 has the highest accuracy (83%), significantly higher than that of CSA combination with CDUS or PDUS (68% and 69%, respectively, P <.05).SMI is more sensitive to display the blood flow in the MN with CTS than CDUS and PDUS. It might significantly improve the diagnosis value for CTS.

  9. Remote Electromagnetic Vibration of Steerable Needles for Imaging in Power Doppler Ultrasound.

    PubMed

    Cabreros, Sarah S; Jimenez, Nina M; Greer, Joseph D; Adebar, Troy K; Okamura, Allison M

    2015-05-01

    Robotic needle steering systems for minimally invasive medical procedures require complementary medical imaging systems to track the needles in real time. Ultrasound is a promising imaging modality because it offers relatively low-cost, real-time imaging of the needle. Previous methods applied vibration to the base of the needle using a voice coil actuator, in order to make the needle visible in power Doppler ultrasound. We propose a new method for needle tip vibration, using electromagnetic actuation of small permanent magnets placed inside the needle to improve needle tip visibility in power Doppler imaging. Robotic needle insertion experiments using artificial tissue and ex vivo porcine liver showed that the electromagnetic tip vibration method can generate a stronger Doppler response compared to the previous base vibration method, resulting in better imaging at greater needle depth in tissue. It also eliminates previous issues with vibration damping along the shaft of the needle.

  10. Remote Electromagnetic Vibration of Steerable Needles for Imaging in Power Doppler Ultrasound

    PubMed Central

    Cabreros, Sarah S.; Jimenez, Nina M.; Greer, Joseph D.; Adebar, Troy K.; Okamura, Allison M.

    2015-01-01

    Robotic needle steering systems for minimally invasive medical procedures require complementary medical imaging systems to track the needles in real time. Ultrasound is a promising imaging modality because it offers relatively low-cost, real-time imaging of the needle. Previous methods applied vibration to the base of the needle using a voice coil actuator, in order to make the needle visible in power Doppler ultrasound. We propose a new method for needle tip vibration, using electromagnetic actuation of small permanent magnets placed inside the needle to improve needle tip visibility in power Doppler imaging. Robotic needle insertion experiments using artificial tissue and ex vivo porcine liver showed that the electromagnetic tip vibration method can generate a stronger Doppler response compared to the previous base vibration method, resulting in better imaging at greater needle depth in tissue. It also eliminates previous issues with vibration damping along the shaft of the needle. PMID:26413379

  11. Investigation of the acute plantar fasciitis with contrast-enhanced ultrasound and shear wave elastography - first results.

    PubMed

    Putz, Franz Josef; Hautmann, Matthias G; Banas, Miriam; Jung, Ernst Michael

    2017-09-04

    The plantar fasciitis is a common disease with a high prevalence in public and a frequent cause of heel pain. In our pilot study, we wanted to characterise the feasibility of shear-wave elastography and contrast-enhanced ultrasound (CEUS) in the assessment of the plantar fasciitis. 23 cases of painful heels were examined by B-Mode ultrasound, Power Doppler (PD), shear wave elastography and contrast-enhanced ultrasound before anti-inflammatory radiation. Time-intensity-curves were analysed by the integrated software. The results for area-under-the-curve (AUC), peak, time-to-peak (TTP) and mean-transit-time (MTT) were compared between the plantar fascia and the surrounding tissue. All cases showed thickening of the plantar fascia, in most cases with interstitial oedema (87.0%). Shear wave elastography showed inhomogeneous stiffness of the plantar fascia. 83.3% of cases showed a visible hyperperfusion in CEUS at the proximal plantar fascia in comparison to the surrounding tissue. This hyperperfusion could also be found in 75.0% of cases with no signs of vascularisation in PD. AUC (p = 0.0005) and peak (p = 0.037) were significantely higher in the plantar fascia than in the surrounding tissue. CEUS and shear wave elastography are new diagnostic tools in the assessment of plantar fasciitis and can provide quantitative parameters for monitoring therapy.

  12. Contrast Enhancement Based on Intrinsic Image Decomposition.

    PubMed

    Yue, Huanjing; Yang, Jingyu; Sun, Xiaoyan; Wu, Feng; Hou, Chunping

    2017-05-10

    In this paper, we propose to introduce intrinsic image decomposition priors into decomposition models for contrast enhancement. Since image decomposition is a highly ill-posed problem, we introduce constraints on both reflectance and illumination layers to yield a highly reliable solution. We regularize the reflectance layer to be piecewise constant by introducing a weighted `1 norm constraint on neighboring pixels according to the color similarity, so that the decomposed reflectance would not be affected much by the illumination information. The illumination layer is regularized by a piecewise smoothness constraint. The proposed model is effectively solved by the Split Bregman algorithm. Then, by adjusting the illumination layer, we obtain the enhancement result. To avoid potential color artifacts introduced by illumination adjusting and reduce computing complexity, the proposed decomposition model is performed on the value channel in HSV space. Experiment results demonstrate that the proposed method performs well for a wide variety of images, and achieves better or comparable subjective and objective quality compared with state-of-the-art methods.

  13. Contrast-enhanced and targeted ultrasound

    PubMed Central

    Postema, Michiel; Gilja, Odd Helge

    2011-01-01

    Ultrasonic imaging is becoming the most popular medical imaging modality, owing to the low price per examination and its safety. However, blood is a poor scatterer of ultrasound waves at clinical diagnostic transmit frequencies. For perfusion imaging, markers have been designed to enhance the contrast in B-mode imaging. These so-called ultrasound contrast agents consist of microscopically small gas bubbles encapsulated in biodegradable shells. In this review, the physical principles of ultrasound contrast agent microbubble behavior and their adjustment for drug delivery including sonoporation are described. Furthermore, an outline of clinical imaging applications of contrast-enhanced ultrasound is given. It is a challenging task to quantify and predict which bubble phenomenon occurs under which acoustic condition, and how these phenomena may be utilized in ultrasonic imaging. Aided by high-speed photography, our improved understanding of encapsulated microbubble behavior will lead to more sophisticated detection and delivery techniques. More sophisticated methods use quantitative approaches to measure the amount and the time course of bolus or reperfusion curves, and have shown great promise in revealing effective tumor responses to anti-angiogenic drugs in humans before tumor shrinkage occurs. These are beginning to be accepted into clinical practice. In the long term, targeted microbubbles for molecular imaging and eventually for directed anti-tumor therapy are expected to be tested. PMID:21218081

  14. Contrast-enhanced and targeted ultrasound.

    PubMed

    Postema, Michiel; Gilja, Odd Helge

    2011-01-07

    Ultrasonic imaging is becoming the most popular medical imaging modality, owing to the low price per examination and its safety. However, blood is a poor scatterer of ultrasound waves at clinical diagnostic transmit frequencies. For perfusion imaging, markers have been designed to enhance the contrast in B-mode imaging. These so-called ultrasound contrast agents consist of microscopically small gas bubbles encapsulated in biodegradable shells. In this review, the physical principles of ultrasound contrast agent microbubble behavior and their adjustment for drug delivery including sonoporation are described. Furthermore, an outline of clinical imaging applications of contrast-enhanced ultrasound is given. It is a challenging task to quantify and predict which bubble phenomenon occurs under which acoustic condition, and how these phenomena may be utilized in ultrasonic imaging. Aided by high-speed photography, our improved understanding of encapsulated microbubble behavior will lead to more sophisticated detection and delivery techniques. More sophisticated methods use quantitative approaches to measure the amount and the time course of bolus or reperfusion curves, and have shown great promise in revealing effective tumor responses to anti-angiogenic drugs in humans before tumor shrinkage occurs. These are beginning to be accepted into clinical practice. In the long term, targeted microbubbles for molecular imaging and eventually for directed anti-tumor therapy are expected to be tested.

  15. Triple-energy contrast enhanced digital mammography

    NASA Astrophysics Data System (ADS)

    Puong, Sylvie; Milioni de Carvalho, Pablo; Muller, Serge

    2010-04-01

    With the injection of iodine, Contrast Enhanced Digital Mammography (CEDM) provides functional information about breast tumour angiogenesis that can potentially help in cancer diagnosis. In order to generate iodine images in which the gray level is proportional to the iodine thickness, temporal and dual-energy approaches have already been considered. The dual-energy method offers the advantage of less patient motion artifacts and better comfort during the exam. However, this approach requires knowledge of the breast thickness at each pixel. Generally, as compression is applied, the breast thickness at each pixel is taken as the compression thickness. Nevertheless, in the breast border region, this assumption is not correct anymore and this causes inaccuracies in the iodine image. Triple-Energy CEDM could overcome these limitations by providing supplemental information in the form of a third image acquired with a different spectrum than the other two. This precludes the need of a priori knowledge of the breast thickness. Moreover, with Triple-Energy CEDM, breast thickness and glandularity maps could potentially be derived. In this study, we first focused on the method to recombine the three images in order to generate the iodine image, analyzing the performance of either quadratic, cubic or conic recombination functions. Then, we studied the optimal acquisition spectra in order to maximize the iodine SDNR in the recombined image for a given target total glandular dose. The concept of Triple-Energy CEDM was validated on simulated textured images and poly-energetic images acquired with a conventional X-ray mammography tube.

  16. Use of power Doppler ultrasound-guided biopsies to locate regions of tumour hypoxia.

    PubMed Central

    Evans, S. M.; Laughlin, K. M.; Pugh, C. R.; Sehgal, C. M.; Saunders, H. M.

    1997-01-01

    The purpose of this study was to determine whether power Doppler ultrasound techniques could be used to direct biopsies into tumour regions with relatively low red blood cell flux, and therefore preferentially sample regions that were relatively hypoxic. Subcutaneous 9L glioma rat tumours were biopsied using power Doppler ultrasound guidance. Immunohistochemical detection of the 2-nitroimidazole EF5 was performed to determine the presence and level of hypoxia in the biopsy samples. Comparisons between the power Doppler-determined red blood cell flux and EF5 binding were made. In seven out of eight tumours studied, power Doppler ultrasound allowed differentiation of a relatively hypoxic region from a relatively oxic region by localizing relatively low vs high red blood cell flux areas respectively. In one of these seven tumours, RBC flux was high in both biopsied sites and hypoxia was not present in either. In two of these seven tumours, hypoxia was present in each biopsy and both of the red blood cell flux measurements were low. In the eighth tumour, both the EF5 binding and the red blood cell flux measurements were low. In this tumour, low EF5 binding was due to the dominance of necrotic cells, which will not reduce or bind EF5 in the biopsy specimen. Using EF5-binding techniques, we have confirmed that regions of relatively low red blood cell flux are more hypoxic than those with relatively high red blood cell flux. Counterstaining specimens with haematoxylin and eosin allows differentiation of low EF5-binding regions due to oxia vs necrosis. These methods have clinical implications for the expanded use of power Doppler ultrasound as a means to direct tissue sampling when it is important to identify the presence of hypoxia. Images Figure 1 Figure 2 Figure 4 Figure 5 PMID:9374376

  17. Power Doppler imaging in detection of surgically induced indirect neoangiogenesis in adult moyamoya disease.

    PubMed

    Perren, Fabienne; Horn, Peter; Vajkoczy, Peter; Schmiedek, Peter; Meairs, Stephen

    2005-11-01

    Moyamoya is a rare, chronic disease that leads to the progressive narrowing and/or occlusion of the distal internal carotid and proximal cerebral arteries. Chronic cerebral ischemia ensues due to insufficient collateral blood supply. One potential treatment consists of the restoration of regional cerebral blood flow by direct or indirect revascularization surgery. The extent of neovascularization, especially in indirect procedures such as encephalomyosynangiosis (EMS), is currently evaluated with conventional angiography. Because this method is invasive and carries some risks, the authors investigated power Doppler imaging as an alternative noninvasive bedside procedure that can be used to assess surgically induced indirect revascularization in adult patients with moyamoya disease. Twelve symptomatic patients with adult moyamoya disease (seven women and five men, mean age 38 +/- 17 years) underwent combined (direct and indirect) revascularization. They were then examined using conventional angiography and power Doppler imaging to assess the extent of revascularization within 120 days postsurgery. According to the number of intracranial vessels demonstrating opacification on conventional angiography and power Doppler imaging studies, EMS was graded as follows: 1, absent (0 vessels); 2, moderate (one-four vessels); and 3, extensive (> four vessels) for both methods. Examiners were blinded to the classification results for the procedure that they did not grade. All 24 hemispheres were examined. The visual grading of EMS revealed a highly significant agreement between conventional angiography and power Doppler imaging (Spearman rank coefficient, r = 0.92; p < 0.001) and there was 100% agreement of patency of the bypass between the direct and indirect methods. The authors found excellent agreement between the two methods. Therefore, power Doppler imaging is a valid noninvasive alternative to carotid artery angiography in evaluating direct and indirect revascularization.

  18. Signal losses with real-time three-dimensional power Doppler imaging.

    PubMed

    Garcia, Damien; Fenech, Marianne; Qin, Zhao; Soulez, Gilles; Cloutier, Guy

    2007-10-01

    Power Doppler imaging (PDI) has been shown to be influenced by the wall filter when assessing arterial stenoses. Real-time 3-D Doppler imaging may likely become a widespread practice in the near future, but how the wall filter could affect PDI during the cardiac cycle has not been investigated. The objective of the study was to demonstrate that the wall filter may produce unexpected major signal losses in real-time 3-D PDI. To test our hypothesis, we first validated binary images obtained from analytical simulations with in vitro PDI acquisitions performed in a tube under pulsatile flow conditions. We then simulated PDI images in the presence of a severe stenosis, considering physiological conditions by finite element modeling. Power Doppler imaging simulations revealed important signal losses within the lumen area at different instants of the flow cycle, and there was a very good concordance between measured and predicted PDI binary images in the tube. Our results show that the wall filter may induce severe PDI signal losses that could negatively influence the assessment of vascular stenosis. Clinicians should therefore be aware of this cause of signal loss to properly interpret power Doppler angiographic images.

  19. The role of transvaginal power Doppler ultrasound in the differential diagnosis of benign intrauterine focal lesions.

    PubMed

    Cogendez, Ebru; Eken, Meryem Kurek; Bakal, Nuray; Gun, Ismet; Kaygusuz, Ecmel Isik; Karateke, Ates

    2015-10-01

    The purpose of this prospective study was to assess the role of power Doppler imaging in the differential diagnosis of benign intrauterine focal lesions such as endometrial polyps and submucous myomas using the characteristics of power Doppler flow mapping. A total of 480 premenopausal patients with abnormal uterine bleeding were evaluated by transvaginal ultrasonography (TVS) searching for intrauterine pathology. Sixty-four patients with a suspicious focal endometrial lesion received saline infusion sonography (SIS) after TVS. Fifty-eight patients with focal endometrial lesions underwent power Doppler ultrasound (PDUS). Three different vascular flow patterns were defined: Single vessel pattern, multiple vessel pattern, and circular flow pattern. Finally, hysteroscopic resection was performed in all cases, and Doppler flow characteristics were then compared with the final histopathological findings. Histopathological results were as follows: endometrial polyp: 40 (69 %), submucous myoma: 18 (31 %). Of the cases with endometrial polyps, 80 % demonstrated a single vessel pattern, 7.5 % a multiple vessel pattern, and 0 % a circular pattern. Vascularization was not observed in 12.5 % of patients with polyps. Of the cases with submucousal myomas, 72.2 % demonstrated a circular flow pattern, 27.8 % a multiple vessel pattern, and none of them showed a single vessel pattern. The sensitivity, specificity, and positive and negative predictive values of the single vessel pattern in diagnosing endometrial polyps were 80, 100, 100, and 69.2 %, respectively; and for the circular pattern in diagnosing submucous myoma, these were 72.2, 100, 100, and 88.9 %, respectively. Power Doppler blood flow mapping is a useful, practical, and noninvasive diagnostic method for the differential diagnosis of benign intrauterine focal lesions. Especially in cases of recurrent abnormal uterine bleeding, recurrent abortion, and infertility, PDUS can be preferred as a first-line diagnostic method.

  20. Acute segmental testicular infarction at contrast-enhanced ultrasound: early features and changes during follow-up.

    PubMed

    Bertolotto, Michele; Derchi, Lorenzo E; Sidhu, Paul S; Serafini, Giovanni; Valentino, Massimo; Grenier, Nicolas; Cova, Maria A

    2011-04-01

    The purpose of this retrospective study was to assess whether contrast-enhanced ultrasound is useful for characterization of acute segmental testicular infarction. Twenty men with acute scrotal pain and suspected segmental testicular infarction underwent contrast-enhanced ultrasound. Three patients underwent orchiectomy. For the other patients, the final diagnosis was based on the absence of tumor markers and a change in the size or shape of the tumor during follow-up. Forty-nine color Doppler ultrasound studies (16 within 24 hours of the onset of pain; 14, 2-17 days after pain onset; 19 after 1 month or more), and 38 contrast-enhanced ultrasound studies (13 within 24 hours after pain onset; nine, 2-17 days; 16 after 1 month or more) were performed. Fourteen of 16 lesions examined within 24 hours were oval, and two were wedge shaped. Eight lesions were isoechoic to the testis, six were hypoechoic, and two had mixed echogenicity. Twelve lesions were avascular and four were hypovascular at color Doppler examination. Contrast-enhanced ultrasound showed avascular parenchymal lobules in all cases and without perilesional rim enhancement in 12 of 13 studies. Two to 17 days after the symptoms appeared, contrast-enhanced ultrasound showed avascular lobules in all cases and perilesional rim enhancement in eight examinations. After 1 month or more, contrast-enhanced ultrasound depicted intralesional vascular spots in 12 of 14 infarcts. Perilesional enhancement was absent. Recognition of lobular morphologic characteristics and the presence of perilesional rim enhancement at contrast-enhanced ultrasound can increase confidence in the diagnosis of segmental testicular infarction compared with reliance on gray-scale and color Doppler findings. Changes in lesion features during follow-up confirm the differential diagnosis from other testicular lesions and allow conservative management.

  1. Effect of power Doppler and digital subtraction techniques on the comparison of myocardial contrast echocardiography with SPECT.

    PubMed

    Haluska, B; Case, C; Short, L; Anderson, J; Marwick, T H

    2001-05-01

    To compare the accuracy and feasibility of harmonic power Doppler and digitally subtracted colour coded grey scale imaging for the assessment of perfusion defect severity by single photon emission computed tomography (SPECT) in an unselected group of patients. Cohort study. Regional cardiothoracic unit. 49 patients (mean (SD) age 61 (11) years; 27 women, 22 men) with known or suspected coronary artery disease were studied with simultaneous myocardial contrast echo (MCE) and SPECT after standard dipyridamole stress. Regional myocardial perfusion by SPECT, performed with (99m)Tc tetrafosmin, scored qualitatively and also quantitated as per cent maximum activity. Normal perfusion was identified by SPECT in 225 of 270 segments (83%). Contrast echo images were interpretable in 92% of patients. The proportion of normal MCE by grey scale, subtracted, and power Doppler techniques were respectively 76%, 74%, and 88% (p < 0.05) at > 80% of maximum counts, compared with 65%, 69%, and 61% at < 60% of maximum counts. For each technique, specificity was lowest in the lateral wall, although power Doppler was the least affected. Grey scale and subtraction techniques were least accurate in the septal wall, but power Doppler showed particular problems in the apex. On a per patient analysis, the sensitivity was 67%, 75%, and 83% for detection of coronary artery disease using grey scale, colour coded, and power Doppler, respectively, with a significant difference between power Doppler and grey scale only (p < 0.05). Specificity was also the highest for power Doppler, at 55%, but not significantly different from subtracted colour coded images. Myocardial contrast echo using harmonic power Doppler has greater accuracy than with grey scale imaging and digital subtraction. However, power Doppler appears to be less sensitive for mild perfusion defects.

  2. Monolithic high peak-power coherent Doppler lidar system

    NASA Astrophysics Data System (ADS)

    Kotov, Leonid V.; Töws, Albert; Kurtz, Alfred; Bobkov, Konstantin K.; Aleshkina, Svetlana S.; Bubnov, Mikhail M.; Lipatov, Denis S.; Guryanov, Alexey N.; Likhachev, Mikhail

    2016-03-01

    In this work we present a monolithic lidar system, based on a newly-developed double-clad large mode area (LMA) polarization-maintaining Er-doped fiber and specially designed LMA passive components. Optimization of the fiber designs resulted in as high as 100 W of SBS limited peak power. The amplifier and its passive components (circulator and collimator) were integrated in an existing lidar system. The enhanced lidar system provides three times increase of scanning range compared to one based on standard telecom-grade amplifiers.

  3. Contrast-enhanced ultrasound in ovarian tumors – diagnostic parameters: method presentation and initial experience

    PubMed Central

    MAXIM, ANITA-ROXANA; BADEA, RADU; TAMAS, ATILLA; TRAILA, ALEXANDRU

    2013-01-01

    The aim of this paper is to discuss and illustrate the use of contrast-enhanced ultrasound in evaluating ovarian tumors compared to conventional ultrasound, Doppler ultrasound and the histopathological analysis and suggest how this technique may best be used to distinguish benign from malignant ovarian masses. We present the method and initial experience of our center by analyzing the parameters used in contrast-enhanced ultrasound in 6 patients with ovarian tumors of uncertain etiology. For examination we used a Siemens ultrasound machine with dedicated contrast software and the contrast agent SonoVue, Bracco. The patients underwent conventional ultrasound, Doppler ultrasound and i.v. administration of the contrast agent. The parameters studied were: inflow of contrast (rise time), time to peak enhancement, mean transit time. The series of patients is part of an extensive prospective PhD study aimed at elaborating a differential diagnosis protocol for benign versus malignant ovarian tumors, by validating specific parameters for contrast-enhanced ultrasound. Although the method is currently used with great success in gastroenterology, urology and senology, its validation in gynecology is still in the early phases. Taking into consideration that the method is minimally invasive and much less costly that CT/MRI imaging, demonstrating its utility in oncologic gynecology would be a big step in preoperative evaluation of these cases. PMID:26527912

  4. Contrast-enhanced ultrasound with perfusion analysis for the identification of malignant and benign tumours of the thyroid gland.

    PubMed

    Wendl, C M; Janke, M; Jung, W; Stroszczysnski, C; Jung, E M

    2015-10-27

    The aim of our study was to evaluate, whether the analysis of time intensity curves (TIC) of contrast enhanced ultrasound (CEUS) could help to differentiate between thyroid adenomas and carcinomas in daily clinical routine.B-mode, Colour Coded Doppler Sonography (CCDS), Power Doppler (PD) and CEUS were applied for 50 patients (27 men, 23 women; mean age 51 years, range 16-81 years).CEUS cine-sequences were analysed using time intensity curves (TIC) and calculating time to peak (TTP) as well as the area under the curve (AUC).All 20 patients with carcinomas presented with a complete wash-out in the late phase of CEUS while this occurred only in three out of the 30 patients with adenomas.Marked differences were observed between adenomas and carcinomas concerning the mean AUC in the surrounding thyroid tissue (p = 0.041). In addition, TTP differed clearly between the centre and the surrounding of the carcinomas (p < 0.05) as well as between TTP in the border area and the surrounding tissue (p = 0.01). CEUS in combination with TIC analysis allows a dynamic evaluation of the microvascularisation of thyroid nodules and is helpful for the differentiation of benign and malignant nodules.

  5. Enhanced Doppler reflectometry power response: physical optics and 2D full wave modelling

    NASA Astrophysics Data System (ADS)

    Pinzón, J. R.; Happel, T.; Blanco, E.; Conway, G. D.; Estrada, T.; Stroth, U.

    2017-03-01

    The power response of a Doppler reflectometer is investigated by means of the physical optics model; a simple model which considers basic scattering processes at the reflection layer. Apart from linear and saturated scattering regimes, non-linear regimes with an enhanced backscattered power are found. The different regimes are characterized and understood based on analytical calculations. The power response is also studied with two-dimensional full wave simulations, where the enhanced backscattered power regimes are also found in qualitative agreement with the physical optics results. The ordinary and extraordinary modes are compared for the same angle of incidence, with the conclusion that the ordinary mode is better suited for Doppler reflectometry turbulence level measurements due to the linearity of its response. The scattering efficiency is studied and a first approximation to describe it is proposed. At the end, the application of the physical optics results to experimental data analysis is discussed. In particular, a formula to assess the linearity of Doppler reflectometry measurements is provided.

  6. Three-dimensional ultrasound power Doppler assessment of the cervix: comparison between nulliparas and multiparas.

    PubMed

    Basgul, Alin; Kavak, Zehra Nese; Bakirci, Nadi; Gokaslan, Husnu

    2007-01-01

    To assess the sonographic cervical characteristics between nulliparous and multiparous women. Transvaginal three-dimensional ultrasound and power Doppler using the virtual organ computer-aided analysis (VOCAL) program were performed on 71 nulliparas and 59 multiparas at a mean gestational age of 25.3+/-7.9 weeks. We compared the cervical volume and power Doppler vascularization index (VI), flow index (FI), and vascularization-flow index (VFI) between nulliparas and multiparas. The mean cervical volume and mean VI, VFI, FI measurements were not significantly different between multiparas and nulliparas. Our observations suggest that the morphological changes in the cervix of parous women are merely configurational without a change in cervical mass and vascularization. These configurational changes might result from the inevitable cervical stretching during labor and represent a healing process that does not involve a subsequent change in mass or vascularity.

  7. Relative blood flow changes measured using calibrated frequency-weighted Doppler power at different hematocrit levels.

    PubMed

    Wallace, Sean; Logallo, Nicola; Faiz, Kashif W; Lund, Christian; Brucher, Rainer; Russell, David

    2014-04-01

    In theory, the power of a trans-cranial Doppler signal may be used to measure changes in blood flow and vessel diameter in addition to velocity. In this study, a flow index (FI) of relative changes in blood flow was derived from frequency-weighted Doppler power signals. The FI, plotted against velocity, was calibrated to the zero intercept with absent flow to reduce the effects of non-uniform vessel insonation. An area index was also calculated. FIs were compared with actual flow in four silicone tubes of different diameter at increasing flow rates and increasing hematocrit (Hct) in a closed-loop phantom model. FI values were strongly correlated with actual flow, at constant Hct, but varied substantially with changes in Hct. Percentage changes in area indexes, relative to the 4-mm tube, were strongly correlated with tube cross-sectional area. The implications of these results for in vivo use are discussed.

  8. Vascular applications of contrast-enhanced ultrasound imaging.

    PubMed

    Mehta, Kunal S; Lee, Jake J; Taha, Ashraf A; Avgerinos, Efthymios; Chaer, Rabih A

    2017-07-01

    Contrast-enhanced ultrasound (CEUS) imaging is a powerful noninvasive modality offering numerous potential diagnostic and therapeutic applications in vascular medicine. CEUS imaging uses microbubble contrast agents composed of an encapsulating shell surrounding a gaseous core. These microbubbles act as nearly perfect intravascular reflectors of ultrasound energy and may be used to enhance the overall contrast and quality of ultrasound images. The purpose of this narrative review is to survey the current literature regarding CEUS imaging and discuss its diagnostic and therapeutic roles in current vascular and selected nonvascular applications. The PubMed, MEDLINE, and Embase databases were searched until July 2016 using the PubMed and Ovid Web-based search engines. The search terms used included contrast-enhanced, microbubble, ultrasound, carotid, aneurysm, and arterial. The diagnostic and therapeutic utility of CEUS imaging has grown exponentially, particularly in the realms of extracranial carotid arterial disease, aortic disease, and peripheral arterial disease. Studies have demonstrated that CEUS imaging is diagnostically superior to conventional ultrasound imaging in identifying vessel irregularities and measuring neovascularization to assess plaque vulnerability and end-muscle perfusion. Groups have begun to use microbubbles as agents in therapeutic applications for targeted drug and gene therapy delivery as well as for the enhancement of sonothrombolysis. The emerging technology of microbubbles and CEUS imaging holds considerable promise for cardiovascular medicine and cancer therapy given its diagnostic and therapeutic utility. Overall, with proper training and credentialing of technicians, the clinical implications are innumerable as microbubble technology is rapidly bursting onto the scene of cardiovascular medicine. Copyright © 2017 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  9. Influence of Pulse Repetition Frequency on 3-D Power Doppler Quantification.

    PubMed

    Soares, Carlos A M; Pavan, Theo Z; Miyague, Andre H; Kudla, Marek; Martins, Wellington P

    2016-12-01

    Three-dimensional power Doppler quantification has limited application because of its high dependency on attenuation. The purpose of the study described here was to assess if different degrees of attenuation, depending on pulse repetition frequency (PRF) adjustment, alter 3-D power Doppler quantification in a region of 100% moving blood when using vascularization index, flow index and vascularization flow index (VFI). A cubic-shaped gelatin phantom with a 1.8-mm-internal-diameter silicon tube was used. The tube, placed at 45° to the phantom's surface, was filled with blood-mimicking fluid with as constant maximum velocity of 30 cm/s. Two different attenuation blocks (low and high attenuation) were alternatively placed between the phantom and the transvaginal transducer. One single observer acquired 10 data sets for each PRF level from 0.3 to 7.5 kHz, using the high- and low-attenuation blocks, for a total of 200 3-D power Doppler data sets. We assessed VFI from 1.5-mm-diameter spherical samples, virtually placed inside the tube, always at the same position. No difference was noted between high- and low-attenuation VFI values when using a PRF of 0.3 kHz. As PRF increased, it was observed that VFI quantification progressively differed between low and high attenuation. Also, a slope on VFI values for both high- and low-attenuation models could be observed when increasing PRF, particularly above 4.0 kHz. We concluded that PRF adjustment is very relevant when using VFI to quantify 3-D power Doppler signal.

  10. Color and power Doppler ultrasonography for characterization of splenic masses in dogs.

    PubMed

    Sharpley, Jenelle L; Marolf, Angela J; Reichle, Jean K; Bachand, Annette M; Randall, Elissa K

    2012-01-01

    Benign and malignant splenic masses can appear similar on B-mode imaging, making ultrasound sensitive but not specific in their diagnosis. Our goal was to characterize color and/or power Doppler characteristics of vasculature within and adjacent to a splenic mass, which would distinguish benign vs. malignant lesions. The hypothesis was that malignant splenic masses will have altered vascular patterns compared with benign masses. Color and power Doppler cineloops evaluating the vasculature within the mass and normal splenic parenchyma were obtained in sagittal and transverse planes using a standardized protocol. Categories of evaluation included presence of peritoneal effusion, a large aberrant or tortuous vessel within the mass, relative blood flow within the mass compared with normal parenchyma, and path of vessels in the adjacent parenchyma entering into the mass. All patients had histopathologic or definitive cytologic diagnosis. Thirty-one dogs were included. There were 13 malignant masses and 18 were benign. Peritoneal effusion was significantly associated with malignancy (P = 0.0007). Presence of an aberrant or tortuous vessel within the mass was nearly significant (P = 0.059). There was no significant difference in any of the color or power Doppler blood flow evaluations. Ultrasonographic findings of a splenic mass and peritoneal effusion may indicate malignancy. The presence of an aberrant vessel within a splenic mass could suggest malignancy; however more data are needed. © 2012 Veterinary Radiology & Ultrasound.

  11. The effectiveness of power Doppler vocal fremitus imaging in the diagnosis of breast hamartoma.

    PubMed

    Yildiz, Seyma; Bakan, Ayse Ahsen; Aydın, Sinem; Kadıoglu, Huseiyn; Serter, Asli; Bilgin, Sennur; Alkan, Alpay

    2014-09-01

    To evaluate the usefulness of power Doppler vocal fremitus (PDVF) breast sonography for differentiation of hamartomas from other breast (malign or benign) masses. Two hundred and six breast masses in 180 women were evaluated. The breast lesions were scanned first by mammography (MG), then by ultrasonography (US) with PDVF imaging. Finally, biopsy was performed on lesions suspicious for malignancy (n=172). We used PDVF imaging to evaluate whether the Power acoustic Doppler artifact existed in all breast lesions. Pathology results of 172 biopsied lesions showed that 83 were malign and 89 masses were benign. Totally 39 breast hamartomas were diagnosed radiologically (n=25) or histopathologically (n=14). All hamartomas (n=39) produced the power acoustic Doppler artifact as the surrounding tissue at the same depth in PDVF imaging. On the other hand, none of the malign or benign lesions, apart from hamartomas, evidenced a similar vibrational artifact as the surrounding tissue at the same depth in the PDVF imaging. PDVF imaging during breast sonography is an invaluable technique in the identification of breast hamartomas from other benign or malign breast masses.

  12. Quantification of blood perfusion using 3D power Doppler: an in-vitro flow phantom study

    NASA Astrophysics Data System (ADS)

    Raine-Fenning, N. J.; Ramnarine, K. V.; Nordin, N. M.; Campbell, B. K.

    2004-01-01

    Three-dimensional (3D) power Doppler data is increasingly used to assess and quantify blood flow and tissue perfusion. The objective of this study was to assess the validity of common 3D power Doppler ‘vascularity’ indices by quantification in well characterised in-vitro flow models. A computer driven gear pump was used to circulate a steady flow of a blood mimicking fluid through various well characterised flow phantoms to investigate the effect of the number of flow channels, flow rate, depth dependent tissue attenuation, blood mimic scatter particle concentration and ultrasound settings. 3D Power Doppler data were acquired with a Voluson 530D scanner and 7.5 MHz transvaginal transducer (GE Kretz). Virtual Organ Computer-aided Analysis software (VOCAL) was used to quantify the vascularisation index (VI), flow index (FI) and vascularisation-flow index (VFI). The vascular indices were affected by many factors, some intuitive and some with more complex or unexpected relationships (e.g. VI increased linearly with an increase in flow rate, blood mimic scatter particle concentration and number of flow channels, and had a complex dependence on pulse repetition frequency). Use of standardised settings and appropriate calibration are required in any attempt at relating ‘vascularity indices’ with flow.

  13. Contrast-enhanced MR Imaging versus Contrast-enhanced US: A Comparison in Glioblastoma Surgery by Using Intraoperative Fusion Imaging.

    PubMed

    Prada, Francesco; Vitale, Valerio; Del Bene, Massimiliano; Boffano, Carlo; Sconfienza, Luca Maria; Pinzi, Valentina; Mauri, Giovanni; Solbiati, Luigi; Sakas, Georgios; Kolev, Velizar; D'Incerti, Ludovico; DiMeco, Francesco

    2017-10-01

    Purpose To compare contrast material enhancement of glioblastoma multiforme (GBM) with intraoperative contrast-enhanced ultrasonography (US) versus that with preoperative gadolinium-enhanced T1-weighted magnetic resonance (MR) imaging by using real-time fusion imaging. Materials and Methods Ten patients with GBM were retrospectively identified by using routinely collected, anonymized data. Navigated contrast-enhanced US was performed after intravenous administration of contrast material before tumor resection. All patients underwent tumor excision with navigated intraoperative US guidance with use of fusion imaging between real-time intraoperative US and preoperative MR imaging. With use of fusion imaging, glioblastoma contrast enhancement at contrast-enhanced US (regarding location, morphologic features, margins, dimensions, and pattern) was compared with that at gadolinium-enhanced T1-weighted MR imaging. Results Fusion imaging for virtual navigation enabled matching of real-time contrast-enhanced US scans to corresponding coplanar preoperative gadolinium-enhanced T1-weighted MR images in all cases, with a positional discrepancy of less than 2 mm. Contrast enhancement of gadolinium-enhanced T1-weighted MR imaging and contrast-enhanced US was superimposable in all cases with regard to location, margins, dimensions, and morphologic features. The qualitative analysis of contrast enhancement pattern demonstrated a similar distribution in contrast-enhanced US and gadolinium-enhanced T1-weighted MR imaging in nine patients: Seven lesions showed peripheral inhomogeneous ring enhancement, and two lesions showed a prevalent nodular pattern. In one patient, the contrast enhancement pattern differed between the two modalities: Contrast-enhanced US showed enhancement of the entire bulk of the tumor, whereas gadolinium-enhanced T1-weighted MR imaging demonstrated peripheral contrast enhancement. Conclusion Glioblastoma contrast enhancement with contrast-enhanced US is

  14. Contrast-enhanced ultrasonography: usefulness in the assessment of postoperative recurrence of Crohn's disease.

    PubMed

    Paredes, José María; Ripollés, Tomás; Cortés, Xavier; Moreno, Nadia; Martínez, María Jesús; Bustamante-Balén, Marco; Delgado, Fructuoso; Moreno-Osset, Eduardo

    2013-04-01

    The aim of this study was to assess whether the contrast-enhanced ultrasonography (CEUS) can increase the value of the ultrasonography in the study of postoperative recurrence of Crohn's disease (CD). 60 patients with CD who had previously undergone ileocolic resection underwent prospectively both CEUS and colonoscopy within a 3-day period. The sonographic examination included evaluation of bowel wall thickness, transmural complications, colour Doppler grade and contrast-enhanced US. In addition a sonographic score was established. The capacity of CEUS to diagnose endoscopic recurrence, as well as its severity, was assessed by calculating the sensitivity, specificity and positive and negative predictive values, accuracy and odds ratio, with their respective 95% confidence intervals. The areas under the receiver operating characteristic (ROC) curves were also calculated. 49 out of 60 patients showed endoscopic postoperative recurrence. Severe endoscopic recurrence was present in 34 patients (57%). Classic ultrasound parameters (wall thickness >3mm and colour Doppler flow) revealed an accuracy of 88.3% for the diagnosis of recurrence. Sonographic score 2, including thickness >5mm or contrast enhancement >46%, improved the results with a sensitivity, specificity and accuracy of 98%, 100% and 98.3%, respectively, in the diagnosis of endoscopic recurrence. The area under the ROC curve was 0.99, in remarkable agreement with endoscopy (k: 0.946). Sonographic score 3, including thickness >5mm, contrast enhancement >70% or fistula identified 32 out of 34 (94.1%) severe endoscopic recurrences. The area under the ROC curve was 0.836, in good agreement with endoscopy (k: 0.688). CEUS shows excellent sensitivity and specificity for the diagnosis of postoperative recurrence in CD and can also detect severe recurrences. Copyright © 2012 European Crohn's and Colitis Organisation. Published by Elsevier B.V. All rights reserved.

  15. Transcranial power M-mode Doppler ultrasound for diagnosis of patent foramen ovale

    NASA Astrophysics Data System (ADS)

    Moehring, Mark; Spencer, Merrill

    2005-04-01

    Patent foramen ovale (PFO) is a right-to-left shunt (RLS) which communicates blood from the right to left atrium of the heart. PFO has been associated with stroke and, more recently, with migraine headache. Diagnosis of RLS can be accomplished effectively with transcranial power M-mode Doppler ultrasound (PMD). PMD is a modality which can be performed without the sedation required by the more invasive diagnostic technique using transesophageal echocardiography. PMD for this application consists of 2 MHz pulse Doppler ultrasound with placement of sample gates at 2 mm intervals along the single-transducer beam axis, and 8 kHz pulse repetition rate (PMD100M, Spencer Technologies). Doppler power versus depth is constructed every 4ms, using 33 sample gates. Bubble microemboli injected in the venous system and moving across a PFO present as high intensity tracks on a PMD image, as emboli transit from the heart to the brain and through the observed cerebral vasculature. Use of PMD in this context has been reported in the clinical literature [M. P. Spencer, M. A. Moehring, J. Jesurum et al, J. Neuroimaging 14, 342-349 (2004)]. This talk surveys the basic technical features of PMD for sensing PFO-related showers of bubble microemboli, and how these features provide clues to the severity of PFO.

  16. Solid focal liver lesions indeterminate by contrast-enhanced CT or MR imaging: the added diagnostic value of contrast-enhanced ultrasound.

    PubMed

    Quaia, Emilio

    2012-08-01

    The main clinically recognized application of contrast-enhanced US (CEUS) with microbubble contrast agents is the characterization of incidental focal liver lesions. CEUS with low transmit power insonation allows the real-time assessment of contrast enhancement in a focal liver lesion after microbubble contrast agent injection, during the arterial (10-25 s), portal venous (from 35 s up to 2 min) and late phase (4-6 min after microbubble injection). During the portal venous and late phase benign lesions appear hyper or iso-enhancing in comparison to the adjacent liver parenchyma, while malignant lesions prevalently present contrast washout with hypo-enhancing appearance. CEUS may provide an added diagnostic value in those incidental focal liver lesions in which contrast-enhanced CT or MR imaging are not conclusive. In particular, CEUS may provide an added diagnostic value in those focal liver lesions appearing indeterminate on single-phase CT scan, or on CT scans performed by an incorrect delay time or also after injection of a low dose of iodinated contrast agent, or also in those focal liver lesions revealing equivocal enhancement patterns on contrast-enhanced CT or MR imaging. CEUS may have an added diagnostic value also in hepatocellular nodules in a cirrhotic liver and can be considered a complementary imaging technique to CT.

  17. Image analysis of placental issues using three-dimensional ultrasound and color power doppler

    NASA Astrophysics Data System (ADS)

    Wang, Qi; Cheng, Qiong; Liu, J. G.

    2007-12-01

    With the development of birthing-process medical science, and insurance requirement of prepotency, the ultrasound technique is widely used in the application of obstetrics realm, especially on the monitoring of embryo's growth. In the recent decade, the introduction of high resolution three-dimensional ultrasonic and color power Doppler scanner provides a much more direct, sensitive, forerunner method for the monitoring of embryo and gravida's prediction. A novel method that depends on examining images of vasculature of placenta to determine the growth of embryo is introduced in this paper. First, get a set of placenta vascularity images of the pregnant woman, taken by Color Doppler Ultrasonic Scanner, then mark some points in these images, where we get a section image, thus we can observe the internal blood vessel distribution at those points. This method provides an efficient tool for doctors.

  18. Understanding quantification of microvascularity with high-frequency power Doppler ultrasound

    NASA Astrophysics Data System (ADS)

    Pinter, Stephen Z.; Lacefield, James C.

    2009-02-01

    High-frequency power Doppler imaging of angiogenesis can be challenging given the presence of small blood vessels and slow flow velocities. In the presence of substantial Doppler artifacts such as false-positive color pixels or undetected vessels, color pixel density (CPD) and related vascularity metrics do not provide accurate estimates of vascular volume fraction. As a step towards improved microvascular quantification, flow-phantom experiments were performed to establish relationships between CPD and wall filter cut-off velocity for various combinations of vessel size (160, 200, 250, 300, and 360 μm), flow velocity (4, 3, 2, 1, and 0.5 mm/s), and transducer frequency (30 and 40 MHz). Three distinct regions were observed in plots of CPD versus wall filter cut-off velocity: overestimation of CPD at low cut-offs, underestimation of CPD at high cut-offs, and a plateau at intermediate cut-offs. The CPD at the plateau closely matched the phantom's actual vascular volume fraction. The length of the plateau corresponded with the flow-detection performance of the Doppler system, which was assessed using receiver operating characteristic analysis. Color pixel density versus wall filter cut-off curves from analogous in vivo experiments exhibited the same shape, including a distinct CPD plateau. The similar shape of the flow-phantom and in vivo curves suggests that the presence of a plateau can be used to identify the best-estimate CPD value in an in vivo experiment. The ability to identify the best CPD estimate is expected to improve quantification of angiogenesis and anti-angiogenic treatment responses with power Doppler.

  19. Non-contrast-enhanced magnetic resonance angiography: techniques and applications.

    PubMed

    Blankholm, Anne Dorte; Ringgaard, Steffen

    2012-01-01

    Non-contrast-enhanced magnetic resonance angiography has gained renewed interest since the discovery of the association between gadolinium-based contrast agents and nephrogenic systemic fibrosis. The following article is an overview of the different magnetic resonance angiography sequences, the technical possibilities and new developments. Clinical options and recent advancements will be highlighted, and recommendations for non-contrast-enhanced magnetic resonance angiography techniques in different anatomical regions will be given. Furthermore, the authors seek to predict the future of non-contrast-enhanced magnetic resonance angiography, with special focus on patients at risk.

  20. Contrast Enhanced Maximum Intensity Projection Ultrasound Imaging for Assessing Angiogenesis in Murine Glioma and Breast Tumor Models: A Comparative Study

    PubMed Central

    Forsberg, Flemming; Ro, Raymond J.; Fox, Traci B; Liu, Ji-Bin; Chiou, See-Ying; Potoczek, Magdalena; Goldberg, Barry B

    2010-01-01

    The purpose of this study was to prospectively compare noninvasive, quantitative measures of vascularity obtained from 4 contrast enhanced ultrasound (US) techniques to 4 invasive immunohistochemical markers of tumor angiogenesis in a large group of murine xenografts. Glioma (C6) or breast cancer (NMU) cells were implanted in 144 rats. The contrast agent Optison (GE Healthcare, Princeton, NJ) was injected in a tail vein (dose: 0.4ml/kg). Power Doppler imaging (PDI), pulse-subtraction harmonic imaging (PSHI), flash-echo imaging (FEI), and Microflow imaging (MFI; a technique creating maximum intensity projection images over time) was performed with an Aplio scanner (Toshiba America Medical Systems, Tustin, CA) and a 7.5 MHz linear array. Fractional tumor neovascularity was calculated from digital clips of contrast US, while the relative area stained was calculated from specimens. Results were compared using a factorial, repeated measures ANOVA, linear regression and z-tests. The tortuous morphology of tumor neovessels was visualized better with MFI than with the other US modes. Cell line, implantation method and contrast US imaging technique were significant parameters in the ANOVA model (p<0.05). The strongest correlation determined by linear regression in the C6 model was between PSHI and percent area stained with CD31 (r=0.37, p<0.0001). In the NMU model the strongest correlation was between FEI and COX-2 (r=0.46, p<0.0001). There were no statistically significant differences between correlations obtained with the various US methods (p>0.05). In conclusion, the largest study of contrast US of murine xenografts to date has been conducted and quantitative contrast enhanced US measures of tumor neovascularity in glioma and breast cancer xenograft models appear to provide a noninvasive marker for angiogenesis; although the best method for monitoring angiogenesis was not conclusively established. PMID:21144542

  1. Detection for processing history of seam insertion and contrast enhancement

    NASA Astrophysics Data System (ADS)

    Li, Jianwei; Zhao, Yao; Ni, Rongrong

    2014-11-01

    With the development of manipulations techniques of digital images, digital image forensic technology is becoming more and more necessary. However, the determination of processing history of multi-operation is still a challenge problem. In this paper, we improve the traditional seam insertion algorithm, and propose corresponding detection method. Then an algorithm that focuses on detecting the processing history of seam insertion and contrast enhancement is proposed, which can be widely used in practical image forgery. Based on comprehensive analysis, we have discovered the inherent relationship between seam insertion and contrast enhancement. Different orders of processing make different impacts on images. By using the newly proposed algorithm, both contrast enhancement followed by seam insertion and seam insertion followed by contrast enhancement can be detected correctly. Plenty of experiments have been implemented to prove the accuracy.

  2. Technology Insight: the role of color and power Doppler ultrasonography in rheumatology.

    PubMed

    Schmidt, Wolfgang A

    2007-01-01

    An increasing number of rheumatologists have access to ultrasound equipment that provide both color and power Doppler modes, which can be used to investigate musculoskeletal and vascular pathologies. Musculoskeletal Doppler ultrasonography can be used to estimate levels of inflammation, to document the anti-inflammatory effect of agents such as corticosteroids and tumor necrosis factor inhibitors, to differentiate between inflammatory and degenerative disease, and to distinguish between normal and inflamed joints in cases of minor synovial swelling. Vascular Doppler ultrasonography can be used to determine organ involvement in small-vessel vasculitides, to delineate aneurysms in vasculitides of medium-sized arteries, and to assess the characteristic findings in large-vessel vasculitis. Numerous studies, including a meta-analysis, have been published on the use of temporal-artery ultrasonography for the diagnosis of giant cell arteritis. Duplex ultrasonography is a sensitive approach for detecting characteristic edematous wall swellings in active temporal arteritis and for assessing vasculitis of the axillary arteries (large-vessel giant cell arteritis) in patients with suspected temporal arteritis, polymyalgia rheumatica, or fever of unknown origin. Duplex ultrasonography can also be used to assess vasculitis of subclavian and carotid arteries in younger patients with Takayasu's arteritis and acute finger artery occlusions in patients with small-vessel vasculitides.

  3. Real-time clinically oriented array-based in vivo combined photoacoustic and power Doppler imaging

    NASA Astrophysics Data System (ADS)

    Harrison, Tyler; Jeffery, Dean; Wiebe, Edward; Zemp, Roger J.

    2014-03-01

    Photoacoustic imaging has great potential for identifying vascular regions for clinical imaging. In addition to assessing angiogenesis in cancers, there are many other disease processes that result in increased vascularity that present novel targets for photoacoustic imaging. Doppler imaging can provide good localization of large vessels, but poor imaging of small or low flow speed vessels and is susceptible to motion artifacts. Photoacoustic imaging can provide visualization of small vessels, but due to the filtering effects of ultrasound transducers, only shows the edges of large vessels. Thus, we have combined photoacoustic imaging with ultrasound power Doppler to provide contrast agent- free vascular imaging. We use a research-oriented ultrasound array system to provide interlaced ultrasound, Doppler, and photoacoustic imaging. This system features realtime display of all three modalities with adjustable persistence, rejection, and compression. For ease of use in a clinical setting, display of each mode can be disabled. We verify the ability of this system to identify vessels with varying flow speeds using receiver operating characteristic curves, and find that as flow speed falls, photoacoustic imaging becomes a much better method for identifying blood vessels. We also present several in vivo images of the thyroid and several synovial joints to assess the practicality of this imaging for clinical applications.

  4. Dual-energy contrast-enhanced spectral mammography (CESM).

    PubMed

    Daniaux, Martin; De Zordo, Tobias; Santner, Wolfram; Amort, Birgit; Koppelstätter, Florian; Jaschke, Werner; Dromain, Clarisse; Oberaigner, Willi; Hubalek, Michael; Marth, Christian

    2015-10-01

    Dual-energy contrast-enhanced mammography is one of the latest developments in breast care. Imaging with contrast agents in breast cancer was already known from previous magnetic resonance imaging and computed tomography studies. However, high costs, limited availability-or high radiation dose-led to the development of contrast-enhanced spectral mammography (CESM). We reviewed the current literature, present our experience, discuss the advantages and drawbacks of CESM and look at the future of this innovative technique.

  5. Potential Cost Savings of Contrast-Enhanced Digital Mammography.

    PubMed

    Patel, Bhavika K; Gray, Richard J; Pockaj, Barbara A

    2017-06-01

    The purpose of this article is to discuss whether the sensitivity and specificity of contrast-enhanced digital mammography (CEDM) render it a viable diagnostic alternative to breast MRI. That CEDM couples low-energy images (comparable to the diagnostic quality of standard mammography) and subtracted contrast-enhanced mammograms make it a cost-effective modality and a realistic substitute for the more costly breast MRI.

  6. Power spectrum and blood flow velocity images obtained by dual-beam backscatter laser Doppler velocimetry

    NASA Astrophysics Data System (ADS)

    Ishida, Hiroki; Yasue, Youichi; Hachiga, Tadashi; Andoh, Tsugunobu; Akiguchi, Shunsuke; Kuraishi, Yasushi; Shimizu, Tadamichi

    2014-07-01

    We developed a micro multipoint laser Doppler velocimeter (μ-MLDV) for noninvasive in-vivo measurements of blood flow and we presented the results of demonstrations performed on experimental animals. In this paper, we investigate the validity of power spectrum analysis for determining the flow velocity and the minimum power of the semiconductor laser in the μ-MLDV. Although average velocity is generally estimated from a peak position ( f peak) in the power spectrum, the power spectrum of blood flow included an additional component in the high-frequency region. The conventional method for determining the average velocity of flows of transparent artificial fluids, which involves determining the average velocity from f peak, is unsuitable for in-vivo measurements of blood flow. The laser power was reduced from 140 to 30mW since 30mW was the minimum power at which images of blood flow velocity in microvessels could be obtained. About 30mW (power density of 15mW/mm2) is the maximum power which can be irradiated to humans. Further reduction in the laser power is necessary before this technique can be applied to humans.

  7. Dynamic contrast-enhanced ultrasound (CEUS) after open and minimally invasive locked plating of proximal humerus fractures.

    PubMed

    Fischer, Christian; Frank, Marion; Kunz, Pierre; Tanner, Michael; Weber, Marc-André; Moghaddam, Arash; Schmidmaier, Gerhard; Hug, Andreas

    2016-08-01

    Closed reduction and locked plate fixation of proximal humerus fractures with the minimally invasive deltoid-splitting approach intends to minimize soft tissue damage although axillary nerve injury has been reported. The aim of this study was to assess the deltoid muscle perfusion with dynamic contrast-enhanced ultrasound (CEUS) as novel technique and evaluate its relation to the functional and neurologic outcome after open (ORIF) and minimally invasive (MIPO) fracture fixation. 50 patients, 30 with deltopectoral ORIF and 20 with deltoid-splitting MIPO approach were examined 6-49 months after surgery. Only patients with a healthy, contralateral shoulder were selected. Shoulder function, satisfaction as well as psychosocial outcome were assessed with established scores (Constant, DASH, Simple Shoulder Test, ASES, SF-12). Electromyography (EMG) of the deltoid muscle was performed to determine axillary nerve damage. Ultrasound of both shoulders included CEUS and Power Doppler after deltoid muscle activation via active abduction for two minutes. None of the examinations and scores showed significant differences between ORIF and MIPO patients, the psychosocial outcome was similar. The fracture types were equally distributed in both groups. The normalized Constant Score was 76.3±18.6 in the ORIF and 81.6±16.1 in the MIPO group (p=0.373). Deltoid muscle perfusion in CEUS and Power Doppler revealed no differences between both approaches. EMG excluded functionally relevant axillary nerve injuries. Compared with the contralateral shoulder, Constant- and ASES-Scores (p≤0.001 for both ORIF and MIPO) as well as the deltoid CEUS perfusion (ORIF p=0.035; MIPO p=0.030) were significantly worse for both approaches. Convincing consensus of functional, ultrasonographic and neurologic examinations demonstrated comparable outcomes after deltopectoral and deltoid-splitting approach. The quantification of the deltoid muscle perfusion with CEUS indicates that the proclaimed benefits

  8. Contrast-enhanced harmonic endoscopic ultrasound in solid lesions of the pancreas: results of a pilot study.

    PubMed

    Napoleon, B; Alvarez-Sanchez, M V; Gincoul, R; Pujol, B; Lefort, C; Lepilliez, V; Labadie, M; Souquet, J C; Queneau, P E; Scoazec, J Y; Chayvialle, J A; Ponchon, T

    2010-07-01

    Distinguishing pancreatic adenocarcinoma from other pancreatic masses remains challenging with current imaging techniques. This prospective study aimed to evaluate the accuracy of a new procedure, imaging the microcirculation pattern of the pancreas by contrast-enhanced harmonic endoscopic ultrasound (CEH-EUS) with a new Olympus prototype echo endoscope. 35 patients presenting with solid pancreatic lesions were prospectively enrolled. All patients had conventional B mode and power Doppler EUS. After an intravenous bolus injection of 2.4 ml of a second-generation ultrasound contrast agent (SonoVue) CEH-EUS was then performed with a new Olympus prototype echo endoscope (xGF-UCT 180). The microvascular pattern was compared with the final diagnosis based on the pathological examination of specimens from surgery or EUS-guided fine-needle aspiration (EUS-FNA) or on follow-up for at least 12 months. The final diagnoses were: 18 adenocarcinomas, 9 neuroendocrine tumors, 7 chronic pancreatitis, and 1 stromal tumor. Power Doppler failed to display microcirculation, whereas harmonic imaging demonstrated it in all cases. Out of 18 lesions with a hypointense signal on CEH-EUS, 16 were adenocarcinomas. The sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), and accuracy of hypointensity for diagnosing pancreatic adenocarcinoma were 89 %, 88 %, 88 %, 89 %, and 88.5 %, compared with corresponding values of 72 %, 100 %, 77 %, 100 %, and 86 % for EUS-FNA. Of five adenocarcinomas with false-negative results at EUS-FNA, four had a hypointense echo signal at CEH-EUS. CEH-EUS with the new Olympus prototype device successfully visualizes the microvascular pattern in pancreatic solid lesions, and may be useful for distinguishing adenocarcinomas from other pancreatic masses.

  9. Temporal subtraction contrast-enhanced dedicated breast CT

    NASA Astrophysics Data System (ADS)

    Gazi, Peymon M.; Aminololama-Shakeri, Shadi; Yang, Kai; Boone, John M.

    2016-09-01

    The development of a framework of deformable image registration and segmentation for the purpose of temporal subtraction contrast-enhanced breast CT is described. An iterative histogram-based two-means clustering method was used for the segmentation. Dedicated breast CT images were segmented into background (air), adipose, fibroglandular and skin components. Fibroglandular tissue was classified as either normal or contrast-enhanced then divided into tiers for the purpose of categorizing degrees of contrast enhancement. A variant of the Demons deformable registration algorithm, intensity difference adaptive Demons (IDAD), was developed to correct for the large deformation forces that stemmed from contrast enhancement. In this application, the accuracy of the proposed method was evaluated in both mathematically-simulated and physically-acquired phantom images. Clinical usage and accuracy of the temporal subtraction framework was demonstrated using contrast-enhanced breast CT datasets from five patients. Registration performance was quantified using normalized cross correlation (NCC), symmetric uncertainty coefficient, normalized mutual information (NMI), mean square error (MSE) and target registration error (TRE). The proposed method outperformed conventional affine and other Demons variations in contrast enhanced breast CT image registration. In simulation studies, IDAD exhibited improvement in MSE (0-16%), NCC (0-6%), NMI (0-13%) and TRE (0-34%) compared to the conventional Demons approaches, depending on the size and intensity of the enhancing lesion. As lesion size and contrast enhancement levels increased, so did the improvement. The drop in the correlation between the pre- and post-contrast images for the largest enhancement levels in phantom studies is less than 1.2% (150 Hounsfield units). Registration error, measured by TRE, shows only submillimeter mismatches between the concordant anatomical target points in all patient studies. The algorithm was

  10. Temporal subtraction contrast-enhanced dedicated breast CT

    PubMed Central

    Gazi, Peymon M.; Aminololama-Shakeri, Shadi; Yang, Kai; Boone, John M.

    2016-01-01

    Purpose To develop a framework of deformable image registration and segmentation for the purpose of temporal subtraction contrast-enhanced breast CT is described. Methods An iterative histogram-based two-means clustering method was used for the segmentation. Dedicated breast CT images were segmented into background (air), adipose, fibroglandular and skin components. Fibroglandular tissue was classified as either normal or contrast-enhanced then divided into tiers for the purpose of categorizing degrees of contrast enhancement. A variant of the Demons deformable registration algorithm, Intensity Difference Adaptive Demons (IDAD), was developed to correct for the large deformation forces that stemmed from contrast enhancement. In this application, the accuracy of the proposed method was evaluated in both mathematically-simulated and physically-acquired phantom images. Clinical usage and accuracy of the temporal subtraction framework was demonstrated using contrast-enhanced breast CT datasets from five patients. Registration performance was quantified using Normalized Cross Correlation (NCC), Symmetric Uncertainty Coefficient (SUC), Normalized Mutual Information (NMI), Mean Square Error (MSE) and Target Registration Error (TRE). Results The proposed method outperformed conventional affine and other Demons variations in contrast enhanced breast CT image registration. In simulation studies, IDAD exhibited improvement in MSE(0–16%), NCC (0–6%), NMI (0–13%) and TRE (0–34%) compared to the conventional Demons approaches, depending on the size and intensity of the enhancing lesion. As lesion size and contrast enhancement levels increased, so did the improvement. The drop in the correlation between the pre- and post-contrast images for the largest enhancement levels in phantom studies is less than 1.2% (150 Hounsfield units). Registration error, measured by TRE, shows only submillimeter mismatches between the concordant anatomical target points in all patient studies

  11. Contrast-enhanced ultrasound with SonoVue in the evaluation of postoperative complications in pediatric liver transplant recipients

    PubMed Central

    Bonini, G.; Pezzotta, G.; Morzenti, C.; Agazzi, R.; Nani, R.

    2007-01-01

    Purpose To evaluate the utility of contrast-enhanced sonography in the study of pediatric liver transplant recipients and its potential impact in reducing the need for invasive diagnostic procedures. Materials and methods From October 2002 to December 2003 we performed routine color Doppler ultrasound and contrast-enhanced ultrasound studies on 30 pediatric patients who had undergone liver transplantation. Findings indicative of complications were confirmed with invasive studies (angiography, computed tomography, and PTC). Results Contrast-enhanced sonography correctly identified four of the five cases of hepatic artery thrombosis and all those involving the portal (n = 6) and hepatic vein (n = 3) thrombosis. It failed to identify one case of hepatic artery thrombosis characterized by collateral circulation arising from the phrenic artery and the single case of hepatic artery stenosis. The latter was more evident on color Doppler, which revealed a typical tardus parvus waveform. The use of contrast offered no significant advantages in the study of biliary complications although it did provide better visualization of bile leaks. Conclusions Contrast-enhanced sonography improves diagnostic confidence and reduces the need for more invasive imaging studies in the postoperative follow-up of pediatric liver transplant recipients. PMID:23396596

  12. Effect of Precompression on the Power Doppler Assessment of Breast Lesion Vascularity.

    PubMed

    DeVita, Robert; Barr, Richard G

    2017-02-01

    To evaluate the effect of precompression on power Doppler visualization of blood flow in breast masses. This Institutional Review Board-approved and Health Insurance Portability and Accountability Act-compliant study evaluated 30 patients with breast masses (16 benign and 14 malignant) undergoing ultrasound-guided breast biopsy. A computational mathematics program was used to calculate the number of color pixels in a region of interest at various degrees of compression of the breast by the transducer. The amount of precompression was calculated as previously described. The percentage of color pixels compared to minimal compression was plotted against the percentage of precompression. The amount of precompression needed to decrease the number of color pixels by 50% and 100% was calculated. The differences between benign and malignant lesions were compared. The mean percentages of precompression ± SD needed to decrease the number of color voxels by 50% in were 15.9% ± 6.43% (range, 8%-30%) for benign lesions and 14.0% ± 4.17% (range, 8%-20%) for malignant lesions (P = .35). The percentages of precompression needed to decrease the number of color pixels by 100% in were 34.7% ± 12.33% (range, 23%-62%) for benign lesions and for malignant lesions 26.7% ± 3.89% (range, 18%-31%), which were statistically significant (P = .027). The amount of precompression normally used when obtaining B-mode images can substantially decrease the number of color voxels on power Doppler sonography. When performing quantitative work on Doppler evaluation of breast lesions, precompression needs to be controlled. © 2016 by the American Institute of Ultrasound in Medicine.

  13. Dynamic contrast enhanced magnetic resonance imaging in chronic Achilles tendinosis.

    PubMed

    Gärdin, Anna; Brismar, Torkel B; Movin, Tomas; Shalabi, Adel

    2013-11-22

    Chronic Achilles tendinosis is a common problem. When evaluating and comparing different therapies there is a need for reliable imaging methods. Our aim was to evaluate if chronic Achilles tendinosis affects the dynamic contrast-enhancement in the tendon and its surroundings and if short-term eccentric calf-muscle training normalizes the dynamic contrast-enhancement. 20 patients with chronic Achilles tendinopathy were included. Median duration of symptoms was 31 months (range 6 to 120 months). Both Achilles tendons were examined with dynamic contrast enhanced MRI before and after a 12- week exercise programme of eccentric calf-muscle training. The dynamic MRI was evaluated in tendon, vessel and in fat ventrally of tendon. Area under the curve (AUC), time to peak of signal, signal increase per second (SI/s) and increase in signal between start and peak as a percentage (SI%) was calculated. Pain and performance were evaluated using a questionnaire. In the fat ventrally of the tendon, dynamic contrast enhancement was significantly higher in the symptomatic leg compared to the contralateral non-symptomatic leg before but not after treatment. Despite decreased pain and improved performance there was no significant change of dynamic contrast enhancement in symptomatic tendons after treatment. In Achilles tendinosis there is an increased contrast enhancement in the fat ventrally of the tendon. The lack of correlation with symptoms and the lack of significant changes in tendon contrast enhancement parameters do however indicate that dynamic enhanced MRI is currently not a useful method to evaluate chronic Achilles tendinosis.

  14. Dynamic contrast enhanced magnetic resonance imaging in chronic Achilles tendinosis

    PubMed Central

    2013-01-01

    Background Chronic Achilles tendinosis is a common problem. When evaluating and comparing different therapies there is a need for reliable imaging methods. Our aim was to evaluate if chronic Achilles tendinosis affects the dynamic contrast-enhancement in the tendon and its surroundings and if short-term eccentric calf-muscle training normalizes the dynamic contrast-enhancement. Methods 20 patients with chronic Achilles tendinopathy were included. Median duration of symptoms was 31 months (range 6 to 120 months). Both Achilles tendons were examined with dynamic contrast enhanced MRI before and after a 12- week exercise programme of eccentric calf-muscle training. The dynamic MRI was evaluated in tendon, vessel and in fat ventrally of tendon. Area under the curve (AUC), time to peak of signal, signal increase per second (SI/s) and increase in signal between start and peak as a percentage (SI%) was calculated. Pain and performance were evaluated using a questionnaire. Results In the fat ventrally of the tendon, dynamic contrast enhancement was significantly higher in the symptomatic leg compared to the contralateral non-symptomatic leg before but not after treatment. Despite decreased pain and improved performance there was no significant change of dynamic contrast enhancement in symptomatic tendons after treatment. Conclusion In Achilles tendinosis there is an increased contrast enhancement in the fat ventrally of the tendon. The lack of correlation with symptoms and the lack of significant changes in tendon contrast enhancement parameters do however indicate that dynamic enhanced MRI is currently not a useful method to evaluate chronic Achilles tendinosis. PMID:24261480

  15. Differentiating between septate and bicornuate uterus: bi-dimensional and 3-dimensional power Doppler findings.

    PubMed

    Nazzaro, Giovanni; Locci, Mariavittoria; Marilena, Miranda; Salzano, Emilia; Palmieri, Teresa; De Placido, Giuseppe

    2014-01-01

    To assess if any difference could be found in uterine vascularization between septate and bicornuate uterus. Pilot study (Canadian Task Force classification II-2). University hospital infertility clinic. One hundred nine women with complete duplication of the uterine cavity. All had already received the final diagnosis of the type of uterine malformation, either septate uterus or bicornuate uterus, via diagnostic hysteroscopy and laparoscopy. Another group of 10 patients with uterine anomalies and affected by ovarian mass were also evaluated via intravenous contrast medium-enhanced ultrasound examination. Patients were evaluated using 2-dimensional and 3-dimensional power Doppler imaging of the uterus. Seventy-three patients with septate uterus, with or without cervical and vaginal duplication, and 36 patients with bicornuate uterus were selected for inclusion in the study. Irregular vascular networks were detected between the 2 hemicavities in the patients with septate uterus. All bicornuate uteri showed a peculiar vascular network between the 2 hemicavities: the main recognizable vessels formed a network depicting the Greek letter γ at the level of the uterine midline. Detection of the γ sign can be used to differentiate septate from bicornuate uterus. This finding was also confirmed in patients who underwent intravenous contrast medium-enhanced ultrasound examination. power Doppler provides a new and uninvasive tool for differentiation of septate from bicornuate uterus. Copyright © 2014 AAGL. Published by Elsevier Inc. All rights reserved.

  16. Enhanced Doppler ultrasound imaging of interstitial laser therapy in rat mammary tumors

    NASA Astrophysics Data System (ADS)

    Zasuly, James M.; Fan, Ming; Dowlatshahi, Kambiz

    1997-05-01

    In order to better develop ultrasonography for use in monitoring interstitial laser therapy (ILT), we imaged rat mammary tumors using power Doppler ultrasound in conduction with intravenous contrast agent (Albunex) before and after laser therapy. Small vessel perfusion throughout a variable portion of the tumor could be detected by power Doppler ultrasound. Lesions created with diode laser by delivery of 500 to 3000 J appeared as perfusion defects on post-treatment images. Image topography and lesion size correlated with gross histologic findings. We conclude that ultrasonographic monitoring of local changes in blood flow using contrast enhancing agent can be useful in characterizing lesions created with ILT.

  17. Contrast-enhanced ultrasound for imaging of adrenal masses.

    PubMed

    Dietrich, C F; Ignee, A; Barreiros, A P; Schreiber-Dietrich, D; Sienz, M; Bojunga, J; Braden, B

    2010-04-01

    The number of incidentally discovered adrenal masses is growing due to the increased use of modern high-resolution imaging techniques. However, the characterization and differentiation of benign and malignant adrenal lesions is challenging. This study aimed to evaluate contrast-enhanced ultrasound for the characterization of adrenal masses. We studied 58 patients with adrenal masses detected with computed tomography, magnetic resonance imaging, or ultrasound. 7 patients had bilateral adrenal lesions. Contrast-enhanced ultrasound was performed using high-resolution ultrasound (3.5 - 7 MHz) and intravenous injection of 2.4 ml SonoVue. The contrast enhancement pattern of all adrenal lesions was documented. The 18 malignant adrenal tumors were significantly larger at the time of diagnosis compared to the 40 benign lesions (p < 0.03). The majority of benign adrenal lesions (37 / 40) had a nonspecific type of contrast enhancement (24 / 40) or a peripheral to central contrast filling (13 / 40) described as the iris phenomenon. Similar findings were observed in malignant adrenal tumors: most malignant lesions also showed nonspecific (6 / 18) or peripheral to central contrast filling (9 / 18). Peripheral to central contrast filling had 50 % sensitivity (26 - 74 %) and 68 % specificity (51 - 81 %) for indicating malignancy. Contrast-enhanced ultrasound facilitates the visualization of vascularization even in small adrenal masses, but it does not help to distinguish malignant and benign lesions. Georg Thieme Verlag KG Stuttgart . New York.

  18. [Contrast-enhanced ultrasound findings of breast cancer].

    PubMed

    Zhang, Jian-xing; Shen, Qiang; Cai, Li-shan; Gao, Lei; Song, Guang-hui; Xie, Xiao-yan; Huang, Jie-xin

    2009-04-01

    To study the manifestation of breast cancers of different sizes in contrast-enhanced sonography. Eighty-four patients with breast cancers were examined by contrast-enhanced ultrasound. Among them, the tumor diameter was beyond 2.0 cm in 50 cases, and no greater than 2.0 cm in the rest cases. The time-intensity curve (TIC) on the enhanced images was analyzed quantitatively, and the relations between the type of TIC and the enhancement patterns of the tumors were analyzed. The enhancement patterns of the breast cancers showed significant difference between patients with tumor diameter beyond 2.0 cm and those with smaller tumors (P<0.01), but the other parameters were comparable between the two groups (P>0.05). The enhancement patterns of breast cancers differ between tumors with sizes over 2.0 cm and smaller tumors, and differential analysis is suggested in the diagnosis of breast cancer using contrast-enhanced ultrasound.

  19. MRI of the human eye using magnetization transfer contrast enhancement.

    PubMed

    Lizak, M J; Datiles, M B; Aletras, A H; Kador, P F; Balaban, R S

    2000-11-01

    To determine the feasibility of using magnetization transfer contrast-enhanced magnetic resonance imaging (MRI) to track cataractous lens changes. A fast spin-echo sequence was modified to include a magnetization transfer contrast (MTC) preparation pulse train. This consisted of twenty 8.5-msec sinc pulses, 1200 Hz upfield from the water resonance and 1.2-Hz power. The MTC preparation pulse was followed by acquisition through fast spin-echo imaging. The imaging parameters were number of excitations (NEX) = 1, echo time (TE) = 14 msec, recovery time (TR) = 2 sec, echo train length of eight echos, and a matrix size of 256 x 160. To reduce motion artifacts, the volunteers were asked to fixate on a blinking LED. Normal and MTC-enhanced images were acquired from normal volunteers and volunteers with nuclear or cortical cataracts. The eye was adequately imaged, with few motion artifacts appearing. The lens was well resolved, despite the short T(2). The cornea and ciliary body were also clearly visible. In the lens, resolution of the epithelium and cortex were enhanced with MTC. In addition, contrast-to-noise ratios were measured for each image. Examination of the contrast-to-noise ratio confirmed that MTC increased the contrast between the nucleus and cortex. Unenhanced MRIs showed significant differences between the cortex of normal volunteers and volunteers with cataracts. MTC-enhanced images improved the sensitivity to changes in the nucleus. In this preliminary study, we were able to use MTC-enhanced MRI to obtain high-contrast images of the human lens. Regular and enhanced MRIs detected statistically significant differences between normal and cataractous lenses.

  20. Visualization of Small-Diameter Vessels by Reduction of Incoherent Reverberation With Coherent Flow Power Doppler.

    PubMed

    Li, You Leo; Hyun, Dongwoon; Abou-Elkacem, Lotfi; Willmann, Juergen Karl; Dahl, Jeremy J

    2016-11-01

    Power Doppler (PD) imaging is a widely used technique for flow detection. Despite the wide use of Doppler ultrasound, limitations exist in the ability of Doppler ultrasound to assess slow flow in the small-diameter vasculature, such as the maternal spiral arteries and fetal villous arteries of the placenta and focal liver lesions. The sensitivity of PD in small vessel detection is limited by the low signal produced by slow flow and the noise associated with small vessels. The noise sources include electronic noise, stationary or slowly moving tissue clutter, reverberation clutter, and off-axis scattering from tissue, among others. In order to provide more sensitive detection of slow flow in small diameter vessels, a coherent flow imaging technique, termed coherent flow PD (CFPD), is characterized and evaluated with simulation, flow phantom experiment studies, and an in vivo animal small vessel detection study. CFPD imaging was introduced as a technique to detect slow blood flow. It has been demonstrated to detect slow flow below the detection threshold of conventional PD imaging using identical pulse sequences and filter parameters. In this paper, we compare CFPD with PD in the detection of blood flow in small-diameter vessels. The results from the study suggest that CFPD is able to provide a 7.5-12.5-dB increase in the signal-to-noise ratio (SNR) over PD images for the same physiological conditions and is less susceptible to reverberation clutter and thermal noise. Due to the increase in SNR, CFPD is able to detect small vessels in high channel noise cases, for which PD was unable to generate enough contrast to observe the vessel.

  1. Understanding the Influence of Flow Velocity, Wall Motion Filter, Pulse Repetition Frequency, and Aliasing on Power Doppler Image Quantification.

    PubMed

    Martins, Maricy R; Martins, Wellington P; Soares, Carlos A M; Miyague, Andre H; Kudla, Marek J; Pavan, Theo Z

    2017-07-24

    Although power Doppler imaging has been used to quantify tissue and organ vascularity, many studies showed that limitations in defining adequate ultrasound machine settings and attenuation make such measurements complex to be achieved. However, most of these studies were conducted by using the output of proprietary software, such as Virtual Organ computer-aided analysis (GE Healthcare, Kretz, Zipf, Austria); therefore, many conclusions may not be generalizable because of unknown settings and parameters used by the software. To overcome this limitation, our goal was to evaluate the impact of the flow velocity, pulse repetition frequency (PRF), and wall motion filter (WMF) on power Doppler image quantification using beam-formed ultrasonic radiofrequency data. The setup consisted of a blood-mimicking fluid flowing through a phantom. Radiofrequency signals were collected using PRFs ranging from 0.6 to 10 kHz for 6 different flow velocities (5-40 cm/s). Wall motion filter cutoff frequencies were varied between 50 and 250 Hz. The power Doppler magnitude was deeply influenced by the WMF cutoff frequency. The effect of using different WMF values varied with the PRF; therefore, the power Doppler signal intensity was dependent on the PRF. Finally, we verified that power Doppler quantification can be affected by the aliasing effect, especially when using a PRF lower than 1.3 kHz. The WMF and PRF greatly influenced power Doppler quantification, mainly when flow velocities lower than 20 cm/s were used. Although the experiments were conducted in a nonclinical environment, the evaluated parameters are equivalent to those used in clinical practice, which makes them valuable for aiding the interpretation of related data in future research. © 2017 by the American Institute of Ultrasound in Medicine.

  2. In vitro evaluation of volumetric flow from Doppler power-weighted and amplitude-weighted mean velocities.

    PubMed

    Minich, L L; Snider, A R; Meliones, J N; Yanock, C

    1993-01-01

    Ultrasound theory suggests that the volume of flow is directly related to the power and amplitude of the backscattered Doppler signals. To evaluate the accuracy of volume flow calculated with power-weighted and amplitude-weighted mean velocities (PWMV and AWMV), volume flows were measured in a pulsatile flow-tank system equipped with a 1.25 cm diameter simulated femoral artery. Analyses were performed throughout a range of physiologic flows, mean driving pressures, and pulse rates. At each hemodynamic setting, volume flow in the simulated artery was measured with an electromagnetic flow probe and with pulsed Doppler echocardiography by use of 7.0 and 3.5 MHz transducers. In addition, to determine the effects of vessel size and parabolic flow on the accuracy of the Doppler volumes, volume flow was evaluated in several differently sized vessels at sampling distances of 20 times the vessel diameter downstream from the orifice. On the ultrasound system, PWMV was calculated as the sum of the individual velocities multiplied by their respective power fractions (the fraction of the total instantaneous power represented by the individual signal power). The instantaneous PWMV was plotted continuously in time and superimposed on the spectral recording. Similarly, AWMV was calculated with amplitudes measured as the square root of the signal power. The PWMV and AWMV were integrated over the flow period and multiplied by the known cross-sectional area of flow to obtain the Doppler volume. In all analyses performed, volumetric flows calculated with Doppler echocardiography with PWMV and AWMV correlated extremely well with those measured with the electromagnetic flow probe. Thus, over a wide range of physiologic conditions, transducers frequencies, and vessel sizes, volume flow can be accurately calculated from PWMV and AWMV Doppler data. This technique provides an accurate, automatic method for on-line determination of volumetric flow.

  3. Could contrast-enhanced CT detect STEMI prior to electrocardiogram?

    PubMed

    Sabbagh, Chadi; Rahi, Mayda; Baz, Maria; Haddad, Fadi; Helwe, Omar; Aoun, Noel; Ibrahim, Tony; Abdo, Lynn

    2015-01-01

    We present here a case in which contrast-enhanced computed tomography (CT) was the first diagnostic tool to detect myocardial hypoperfusion in a patient with atypical symptoms and normal electrocardiogram (ECG) on admission. An ST-segment elevation was detected thereafter on a second ECG realized several minutes after CT with raised troponin levels. Percutaneous coronary intervention was performed after failure of thrombolysis and confirmed occlusion of the left anterior descending artery. Further studies are needed to evaluate the role of high-resolution contrast-enhanced CT with or without coronary angiography in the workup of suspected myocardial infarction in the setting of a normal ECG.

  4. Dynamic contrast-enhanced endoscopic ultrasound: A quantification method

    PubMed Central

    Dietrich, Christoph F.; Dong, Yi; Froehlich, Eckhart; Hocke, Michael

    2017-01-01

    Dynamic contrast-enhanced ultrasound (DCE-US) has been recently standardized by guidelines and recommendations. The European Federation of Societies for US in Medicine and Biology position paper describes the use for DCE-US. Comparatively, little is known about the use of contrast-enhanced endoscopic US (CE-EUS). This current paper reviews and discusses the clinical use of CE-EUS and DCE-US. The most important clinical use of DCE-US is the prediction of tumor response to new drugs against vascular angioneogenesis. PMID:28218195

  5. Determining radiated sound power of building structures by means of laser Doppler vibrometry

    NASA Astrophysics Data System (ADS)

    Roozen, N. B.; Labelle, L.; Rychtáriková, M.; Glorieux, C.

    2015-06-01

    This paper introduces a methodology that makes use of laser Doppler vibrometry to assess the acoustic insulation performance of a building element. The sound power radiated by the surface of the element is numerically determined from the vibrational pattern, offering an alternative for classical microphone measurements. Compared to the latter the proposed analysis is not sensitive to room acoustical effects. This allows the proposed methodology to be used at low frequencies, where the standardized microphone based approach suffers from a high uncertainty due to a low acoustic modal density. Standardized measurements as well as laser Doppler vibrometry measurements and computations have been performed on two test panels, a light-weight wall and a gypsum block wall and are compared and discussed in this paper. The proposed methodology offers an adequate solution for the assessment of the acoustic insulation of building elements at low frequencies. This is crucial in the framework of recent proposals of acoustic standards for measurement approaches and single number sound insulation performance ratings to take into account frequencies down to 50 Hz.

  6. Spatial entropy-based global and local image contrast enhancement.

    PubMed

    Celik, Turgay

    2014-12-01

    This paper proposes a novel algorithm, which enhances the contrast of an input image using spatial information of pixels. The algorithm introduces a new method to compute the spatial entropy of pixels using spatial distribution of pixel gray levels. Different than the conventional methods, this algorithm considers the distribution of spatial locations of gray levels of an image instead of gray-level distribution or joint statistics computed from the gray levels of an image. For each gray level, the corresponding spatial distribution is computed using a histogram of spatial locations of all pixels with the same gray level. Entropy measures are calculated from the spatial distributions of gray levels of an image to create a distribution function, which is further mapped to a uniform distribution function to achieve the final contrast enhancement. The method achieves contrast improvement in the case of low-contrast images; however, it does not alter the image if the image’s contrast is high enough. Thus, it always produces visually pleasing results without distortions. Furthermore, this method is combined with transform domain coefficient weighting to achieve both local and global contrast enhancement at the same time. The level of the local contrast enhancement can be controlled. Several experiments on effects of contrast enhancement are performed. Experimental results show that the proposed algorithms produce better or comparable enhanced images than several state-of-the-art algorithms.

  7. Power Doppler ultrasonographic assessment of the ankle in patients with inflammatory rheumatic diseases.

    PubMed

    Suzuki, Takeshi

    2014-11-18

    Ankle involvement is frequent in patients with inflammatory rheumatic diseases, but accurate evaluation by physical examination is often difficult because of the complex anatomical structures of the ankle. Over the last decade, ultrasound (US) has become a practical imaging tool for the assessment of articular and periarticular pathologies, including joint synovitis, tenosynovitis, and enthesitis in rheumatic diseases. Progress in power Doppler (PD) technology has enabled evaluation of the strength of ongoing inflammation. PDUS is very useful for identifying the location and kind of pathologies in rheumatic ankles as well as for distinguishing between inflammatory processes and degenerative changes or between active inflammation and residual damage. The aim of this paper is to illustrate the US assessment of ankle lesions in patients with inflammatory rheumatic diseases, including rheumatoid arthritis, spondyloarthritis, and systemic lupus erythematosus, focusing on the utility of PDUS.

  8. Power Doppler ultrasonographic assessment of the ankle in patients with inflammatory rheumatic diseases

    PubMed Central

    Suzuki, Takeshi

    2014-01-01

    Ankle involvement is frequent in patients with inflammatory rheumatic diseases, but accurate evaluation by physical examination is often difficult because of the complex anatomical structures of the ankle. Over the last decade, ultrasound (US) has become a practical imaging tool for the assessment of articular and periarticular pathologies, including joint synovitis, tenosynovitis, and enthesitis in rheumatic diseases. Progress in power Doppler (PD) technology has enabled evaluation of the strength of ongoing inflammation. PDUS is very useful for identifying the location and kind of pathologies in rheumatic ankles as well as for distinguishing between inflammatory processes and degenerative changes or between active inflammation and residual damage. The aim of this paper is to illustrate the US assessment of ankle lesions in patients with inflammatory rheumatic diseases, including rheumatoid arthritis, spondyloarthritis, and systemic lupus erythematosus, focusing on the utility of PDUS. PMID:25405085

  9. Power Doppler myocardial contrast echocardiography using an improved multiple frame triggered Harmonic Angio technique.

    PubMed

    Murthy, T H; Locricchio, E; Kuersten, B; Li, P; Baisch, C; Vannan, M A

    2001-04-01

    Although B-mode harmonic, intermittent-triggered myocardial contrast echocardiography (MCE) is a well-established technique, a variety of MCE techniques have been introduced recently to improve myocardial opacification. One such technique uses a power Doppler method in conjunction with multiple frame triggering (MFT), but has been limited by nonuniform microbubble destruction and blooming as well as motion artifacts. Utilizing two different contrast agents, Definity and Optison, we tested the feasibility of an improved version of Harmonic Angio MFT that utilizes a lower transmit frequency, reduced packet size, and more stringent wall filter in normal volunteers and in patients with known perfusion defects. The results showed that Harmonic Angio MFT produced fill frames with readily visible opacification and destruction frames with little visible opacification. The patterns of opacification also correlated with the expected perfusion patterns in both groups of subjects. Thus, Harmonic Angio MFT appears to be a promising new MCE technique.

  10. Derivation of power M-mode transcranial Doppler criteria for angiographic proven MCA occlusion.

    PubMed

    Saqqur, Maher; Hill, Michael D; Alexandrov, Andrei V; Roy, Jayanta; Schebel, Marcia; Krol, Andrea; Garami, Zsolt; Shuaib, Ashfaq; Demchuk, Andrew M

    2006-10-01

    Stringent transcranial Doppler (TCD) criteria for diagnosing occlusion are needed for more reliable TCD performance at bedside in the acute stroke setting. At three academic stroke centers, we performed TCD examination for patients with symptoms of cerebral ischemia who underwent digital subtraction angiography (DSA). We used a standard insonation protocol with power M-mode Doppler (PMD) TCD (TCD 100 M, Spencer Technologies Inc., Seattle, WA). We collected mean flow velocity (MFV), pulsatility indices (PI), and power M-mode resistance signature (absent, high, or low) in symptomatic middle (MCA), anterior (ACA), posterior (PCA), and in affected (a), ipsilateral (i), and contralateral (c-lat) cerebral arteries. Ratios of aMCA/c-lat MCA, aMCA/iACA, and aMCA/iPCA MFV were subsequently calculated. PMD-TCD flow findings were evaluated with a receiver-operating characteristic (ROC) analysis for angiographically proven MCA occlusion. We studied 120 patients with acute cerebral ischemia with PMD-TCD examinations prior to or immediately after DSA. Lower aMCA velocities pointed to higher probability of occlusion (P= .055). The aMCA/iPCA MFV ratio was superior to the aMCA/iACA ratio and strongly predictive of occlusion at a threshold ratio of 0.5 (RR 2.31 CI(95) 2.13-2.51). High resistance or absent M-mode flow signatures in the proximal MCA were present in 87% of M1 and M2 MCA occlusions (probability 87%). In the presence of a low-resistance PMD signature, obtaining the aMCA/iPCA MFV ratio <0.5 increases probability of occlusion to 87%. Normal MFV ratios and low-resistance M-mode signatures are highly predictive of a negative angiogram for MCA occlusion. In acute cerebral ischemia, reliable criteria for proximal MCA occlusion have been developed based on combination of MFV ratios and M-mode flow resistance signatures. Validation of these criteria will require multicenter studies.

  11. Power and pulsed Doppler evaluation of ovarian hemodynamic changes during diestrus in pregnant and nonpregnant bitches.

    PubMed

    Polisca, A; Zelli, R; Troisi, A; Orlandi, R; Brecchia, G; Boiti, C

    2013-01-15

    The aim of the study was to further characterize the relationship between hemodynamic changes in the ovary and luteal function in pregnant and nonpregnant bitches. Fourteen German Shepherd bitches were monitored three times a week from the first day of cytological diestrus (D1) until parturition or the end of diestrus (progesterone <2 ng/mL) by color Doppler, pulsed wave spectral Doppler, and power Doppler (PD) ultrasonography. By means of PD the total number of color pixels were calculated. The Doppler parameters evaluated were: peak systolic velocity (PSV), end diastolic velocity (EDV), and both resistive and pulsatility indices. Blood samples were collected three times a week throughout the experiment to determine progesterone (P4) concentrations. The length of diestrus in pregnant versus nonpregnant group was significantly shorter (P < 0.01; 57 ± 1 vs. 63 ± 1, respectively). By means of pulsed wave spectral Doppler the waveform showed a typical pattern of a low-resistive vessel characterized by a rapid systolic peak followed by a slow telediastolic decrease with a relatively high end-diastolic velocity. Blood flow parameters did not differ between left and right ovary. In both groups PSV and EDV showed a gradual decrease with the progress of diestrus; however, the values of PSV and EDV were significantly higher (P < 0.05) in the pregnant group versus nonpregnant group from D31 to D61 and from D49 to D58 respectively. Moreover, a significantly decrease (P < 0.05) of PSV and EDV in the pregnant group was observed from D46 to D58 and from D49 to D55, respectively. The resistive and pulsatility indices showed an increase during diestrus and the values were significantly lower (P < 0.05) in the pregnant group from D49 to D61. By means of PD, the pixel number was significantly higher (P < 0.05) in the pregnant versus nonpregnant group from D40 to D61. In particular, a significant decrease (P < 0.05) in the pixel number in the pregnant group was observed from D46 to

  12. Transvaginal 3-d power Doppler ultrasound evaluation of the fetal brain at 10-13 weeks' gestation.

    PubMed

    Hata, Toshiyuki; Tanaka, Hirokazu; Noguchi, Junko

    2012-03-01

    The objective of this study was to measure the fetal brain volume (FBV) and vascularization and blood flow using transvaginal 3-D power Doppler (3DPD) ultrasound late in the first trimester of pregnancy. 3DPD ultrasound examinations with the VOCAL imaging analysis program were performed on 36 normal fetuses from 10-13 weeks' gestation. FBV and 3DPD indices related to the fetal brain vascularization (vascularization index [VI], flow index [FI] and vascularization flow index [VFI]) were calculated in each fetus. Intra- and interclass correlation coefficients and intra- and interobserver agreements of measurements were assessed. FBV was curvilinearly correlated well with the gestational age (R2 = 0.861, p < 0.0001). All 3-D power Doppler indices (VI, FI and VFI) showed no change at 10-13 weeks' gestation. FBV and all 3-D power Doppler indices (VI, FI and VFI) showed a correlation > 0.82, with good intra- and interobserver agreement. Our findings suggest that 3-D ultrasound is a superior means of evaluating the FBV in utero, and that 3-D power Doppler ultrasound histogram analysis may provide new information on the assessment of fetal brain perfusion.

  13. Prostate vascular flow: The effect of the ejaculation on the power doppler ultrasonographic examination.

    PubMed

    Alonge, S; Melandri, M; Fanciullo, L; Lacalandra, G M; Aiudi, G

    2017-09-11

    Power Doppler sonography (PD) can accurately depict tissue perfusion, recognize slow flows, and is relatively angle independent. The monitoring of local blood flow by Doppler ultrasonography is helpful in differentiating prostatic physio-pathological conditions, but the recognizing of physiological variables that could affect it is crucial to apply this technique in clinical practice. This study aimed to evaluate if ejaculation affects blood flow to the prostate and to state how long this effect lasts. Serial PD examinations of prostate were performed in 18 dogs (1-5 years, 6-40 kg) immediately before (T0) and after (T1) the ejaculation, and repeated 6 (T2), 18 (T3) and 24 (T4) hours later. For each examination, two representative PD images were chosen and ranked by two independent observers according to the following scoring system: 0 = mild subcapsular (S) vascularization without clear evidence of parenchymal (P) vascularization; 1 = moderate P and S vascularization; 2 = severe S and moderate P vascularization; 3 = severe P and moderate S vascularization; 4 = severe P and S vascularization. Interobserver agreement was assessed using Kappa of Cohen. Ranked data, grouped according to time, were compared by ANOVA and Tukey HSD test (p < .05). Variations in the vascular flow pattern at different times were observed for all dogs. The statistical analysis evidenced a significant difference for T0 vs T1 and vs T2 and vs T3 (p < .01), with no significant difference for T0 vs T4 (p > .05). Interobserver agreement was very good (Kappa of Cohen = 0.86). This study demonstrated a definite increase in vascular flow to the prostate after ejaculation. The present results suggest a minimum of 24 hr sexual rest before the PD examination of the gland. This result should be taken into account whenever Doppler sonography is used to evaluate potential hyperaemia in dogs suspected of having prostate abnormalities. © 2017 Blackwell Verlag GmbH.

  14. Changes of renal blood flow after ESWL: assessment by ASL MR imaging, contrast enhanced MR imaging, and renal resistive index.

    PubMed

    Abd Ellah, Mohamed; Kremser, Christian; Pallwein, Leo; Aigner, Friedrich; Schocke, Michael; Peschel, Reinhard; Pedross, Florian; Pinggera, Germar-Michael; Wolf, Christian; Alsharkawy, Mostafa A M; Jaschke, Werner; Frauscher, Ferdinand

    2010-10-01

    The annual incidence of stone formation is increased in the industrialised world. Extracorporeal shockwave lithotripsy is a non-invasive effective treatment of upper urinary tract stones. This study is aimed to evaluate changes of renal blood flow in patients undergoing extracorporeal shock wave lithotripsy (ESWL) by arterial spin labeling (ASL) MR imaging, contrast enhanced dynamic MR imaging, and renal resistive index (RI). Thirteen patients with nephrolithiasis were examined using MR imaging and Doppler ultrasound 12h before and 12h after ESWL. ASL sequence was done for both kidneys and followed by contrast enhanced MR imaging. In addition RI Doppler ultrasound measurements were performed. A significant increase in RI (p<0.001) was found in both treated and untreated kidneys. ASL MR imaging also showed significant changes in both kidneys (p<0.001). Contrast enhanced dynamic MR imaging did not show significant changes in the kidneys. ESWL causes changes in RI and ASL MR imaging, which seem to reflect changes in renal blood flow.

  15. Ultrasound resistive index, power Doppler, and clinical parameters in established rheumatoid arthritis.

    PubMed

    Bisi, Melissa Cláudia; do Prado, Aline Defaveri; Piovesan, Deise Marcela; Bredemeier, Markus; da Silveira, Inês Guimarães; de Mendonça, José Alexandre; Staub, Henrique Luiz

    2017-04-01

    Ultrasonography (US) is a useful tool for the evaluation of sinovial vascularization and proliferation in rheumatoid arthritis (RA). Accordingly, resistive index (RI) on spectral Doppler (sD) US provides a quantitative analysis of vascular inflammation, but its utility in the evaluation of RA activity has not been established. Our objective was to determine the association of RI with other US parameters of synovitis and with clinical disease activity in established RA. Patients with positive power Doppler (pD) were included in a prospective cross-sectional study. Disease activity and disability were evaluated using the Disease Activity Score in 28-joints (DAS28) and Health Assessment Questionnaire (HAQ), respectively. Gray scale (GS) synovitis, pD, and sD analyses were performed by one of two examiners in wrists and the second and third metacarpophalangeal and proximal interphalangeal joints. The 10-joint GS and 10-joint pD scores and mean RI were then calculated. Weighted kappa (WK) values were employed to assess interobserver reability, and correlations were tested using the Spearman coefficient. Ninety-five RA patients (median duration of disease of 7 years and mean DAS28 of 4.32 ± 1.66) were included. WK values in real-time US were 0.77 for synovitis, 0.87 for pD, and 0.68 for RI. There were no significant correlations of RI with 10-joint GS, 10-joint pD, DAS28, joint counts, or HAQ (P > 0.10 for all tests). Patients in remission had a mean RI similar to those with high disease activity (0.62 ± 0.10, n = 15 versus 0.63 ± 0.13, n = 34, respectively). The addition of the RI score did not seem to improve US performance in patients with established RA.

  16. Insonation method and diagnostic flow signatures for transcranial power motion (M-mode) Doppler.

    PubMed

    Alexandrov, Andrei V; Demchuk, Andrew M; Burgin, W Scott

    2002-07-01

    Power motion mode Doppler (PMD) simultaneously displays flow signal intensity and direction over several centimeters of intracranial space. Insonation protocol for PMD and spectral transcranial Doppler (TCD) with typical PMD flow signatures is described in serial patients with acute stroke symptoms examined via conventional windows with a PMD/TCD unit. Thirty-five patients were studied within 12 hours after stroke onset (age 64 +/- 15 years; 8 received intravenous and 3 intra-arterial thrombolysis). One patient had no temporal window, and 3 patients had suboptimal windows. In 90% of patients, PMD showed more than 1 ipsilateral temporal windows. In 63% of patients (n = 22), PMD simultaneously displayed the entire M1 (65-45 mm) and proximal M2 (45-30 mm) flows, leading to spectral TCD examination of the proximal M2 middle cerebral artery (MCA) in 28 of 35 patients (80%). All patients had sufficient foraminal (depth display = 60-110 mm) and orbital (depth display = 30-80 mm) windows. PMD displayed the entire basilar artery stem (75-100+ mm) in 69% (n = 24) of patients, and the distal basilar flow was detected in all patients by both PMD and TCD. TCD results were normal (12), proximal intracranial stenosis (5), large vessel occlusion (17), and cerebral circulatory arrest (1). Compared to spectral TCD, PMD signatures of similar diagnostic significance were low resistance (vessel identification and recanalization), high resistance (ophthalmic artery identification and distal obstruction), collateral (communicating arteries and leptomeningeal flow), reverberating (circulatory arrest), and branch embolization. PMD is a window-finding tool and a guide for spectral TCD gate placement. PMD facilitates flow detection in the M2 branches and the distal basilar artery. PMD can demonstrate recanalization of the entire MCA main stem and proximal branches, increase the yield of embolus detection and procedure monitoring, and facilitate abnormal flow pattern recognition.

  17. Contrast-enhanced photoacoustic tomography of human joints

    NASA Astrophysics Data System (ADS)

    Tian, Chao; Keswani, Rahul K.; Gandikota, Girish; Rosania, Gus R.; Wang, Xueding

    2016-03-01

    Photoacoustic tomography (PAT) provides a unique tool to diagnose inflammatory arthritis. However, the specificity and sensitivity of PAT based on endogenous contrasts is limited. The development of contrast enhanced PAT imaging modalities in combination with small molecule contrast agents could lead to improvements in diagnosis and treatment of joint disease. Accordingly, we adapted and tested a PAT clinical imaging system for imaging the human joints, in combination with a novel PAT contrast agent derived from an FDA-approved small molecule drug. Imaging results based on a photoacoustic and ultrasound (PA/US) dual-modality system revealed that this contrast-enhanced PAT imaging system may offer additional information beyond single-modality PA or US imaging system, for the imaging, diagnosis and assessment of inflammatory arthritis.

  18. Contrast enhanced exposure strategy in multi-beam mask writing

    NASA Astrophysics Data System (ADS)

    Belic, Nikola; Hofmann, Ulrich; Klikovits, Jan; Martens, Stephan

    2013-03-01

    Since multi electron beam exposure has become a serious contender for next generation mask making, proximity- and process effect corrections (PEC) need to be adapted to this technology. With feature sizes in the order of the short-range blurs (resist and tool), contrast enhancements need to be combined with standard linearity corrections. Different PEC strategies are reviewed and compared with respect to their suitability for multi-beam exposure. This analysis recommends a hybrid approach that combines the benefits of shape- and dose PEC and is optimally applicable for multibeam exposure. Exposure results on the proof-of-concept 50keV electron multi-beam mask exposure tool (eMET POC) and a standard 50 kV vector shaped beam tool (VSB) are shown to verify that the combined PEC with overdose contrast enhancement covers the whole pattern range from isolated to opaque.

  19. Gasserian ganglion: appearance on contrast-enhanced MR.

    PubMed

    Downs, D M; Damiano, T R; Rubinstein, D

    1996-02-01

    To characterize the appearance of the gasserian ganglion on contrast-enhanced MR images. We retrospectively reviewed the MR images from 57 patients with suspected pituitary disease. These patients had undergone unenhanced and contrast-enhanced MR imaging of the sella, including evaluation of Meckel's cave. None of the patients had clinical signs or symptoms referable to the fifth cranial nerve or ganglion. Correlation was made with a previous study that compared gross anatomy with high-resolution CT scans of cadaveric specimens. A discrete semilunar enhancing structure within the inferolateral aspect of Meckel's cave was identified in 100 of the 114 caves examined; the other 14 caves had a thickened area of enhancement that blended with the dura inferolaterally. A small semilunar structure within the inferolateral aspect of Meckel's cave was also identified on CT scans of the cadaveric specimens. The gasserian ganglion enhances on MR images and should not be confused with a pathologic process.

  20. Diffeomorphic Registration of Images with Variable Contrast Enhancement

    PubMed Central

    Janssens, Guillaume; Jacques, Laurent; Orban de Xivry, Jonathan; Geets, Xavier; Macq, Benoit

    2011-01-01

    Nonrigid image registration is widely used to estimate tissue deformations in highly deformable anatomies. Among the existing methods, nonparametric registration algorithms such as optical flow, or Demons, usually have the advantage of being fast and easy to use. Recently, a diffeomorphic version of the Demons algorithm was proposed. This provides the advantage of producing invertible displacement fields, which is a necessary condition for these to be physical. However, such methods are based on the matching of intensities and are not suitable for registering images with different contrast enhancement. In such cases, a registration method based on the local phase like the Morphons has to be used. In this paper, a diffeomorphic version of the Morphons registration method is proposed and compared to conventional Morphons, Demons, and diffeomorphic Demons. The method is validated in the context of radiotherapy for lung cancer patients on several 4D respiratory-correlated CT scans of the thorax with and without variable contrast enhancement. PMID:21197460

  1. Diffeomorphic registration of images with variable contrast enhancement.

    PubMed

    Janssens, Guillaume; Jacques, Laurent; Orban de Xivry, Jonathan; Geets, Xavier; Macq, Benoit

    2011-01-01

    Nonrigid image registration is widely used to estimate tissue deformations in highly deformable anatomies. Among the existing methods, nonparametric registration algorithms such as optical flow, or Demons, usually have the advantage of being fast and easy to use. Recently, a diffeomorphic version of the Demons algorithm was proposed. This provides the advantage of producing invertible displacement fields, which is a necessary condition for these to be physical. However, such methods are based on the matching of intensities and are not suitable for registering images with different contrast enhancement. In such cases, a registration method based on the local phase like the Morphons has to be used. In this paper, a diffeomorphic version of the Morphons registration method is proposed and compared to conventional Morphons, Demons, and diffeomorphic Demons. The method is validated in the context of radiotherapy for lung cancer patients on several 4D respiratory-correlated CT scans of the thorax with and without variable contrast enhancement.

  2. Fundamentals of tracer kinetics for dynamic contrast-enhanced MRI.

    PubMed

    Koh, Tong San; Bisdas, Sotirios; Koh, Dow Mu; Thng, Choon Hua

    2011-12-01

    Tracer kinetic methods employed for quantitative analysis of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) share common roots with earlier tracer studies involving arterial-venous sampling and other dynamic imaging modalities. This article reviews the essential foundation concepts and principles in tracer kinetics that are relevant to DCE MRI, including the notions of impulse response and convolution, which are central to the analysis of DCE MRI data. We further examine the formulation and solutions of various compartmental models frequently used in the literature. Topics of recent interest in the processing of DCE MRI data, such as the account of water exchange and the use of reference tissue methods to obviate the measurement of an arterial input, are also discussed. Although the primary focus of this review is on the tracer models and methods for T(1) -weighted DCE MRI, some of these concepts and methods are also applicable for analysis of dynamic susceptibility contrast-enhanced MRI data.

  3. Contrast enhancement of high-energy radiotherapy films.

    PubMed

    Reinstein, L E; Orton, C G

    1979-11-01

    An order-of-magnitude improvment in the contrast of high-energy localization and verification films has been achieved through the application of a simple, inexpensive, contrast enhancement technique. The method involves making reversal contact "prints" of the original film onto ordinary X-ray fi-m with equipment commonly available in any radiotherapy department. This results in "gamma multiplication". The theory as well as several applications of this effect are presented.

  4. Sequential contrast-enhanced MR imaging of the penis.

    PubMed

    Kaneko, K; De Mouy, E H; Lee, B E

    1994-04-01

    To determine the enhancement patterns of the penis at magnetic resonance (MR) imaging. Sequential contrast material-enhanced MR images of the penis in a flaccid state were obtained in 16 volunteers (12 with normal penile function and four with erectile dysfunction). Subjects with normal erectile function showed gradual and centrifugal enhancement of the corpora cavernosa, while those with erectile dysfunction showed poor enhancement with abnormal progression. Sequential contrast-enhanced MR imaging provides additional morphologic information for the evaluation of erectile dysfunction.

  5. Effects of transducer beam geometry and flow velocity profile on the Doppler power spectrum: a theoretical study.

    PubMed

    Bascom, P A; Cobbold, R S

    1990-01-01

    A theoretical model is used to show how the Doppler spectrum for various axisymmetric velocity profiles is affected by beam misalignment and incomplete insonation. Results are presented for both circular and square beam geometries. Moreover, a closed-form expression is derived for the power spectral density received by an on-axis transducer with a Gaussian beam profile. It is shown that the error incurred in measuring the mean Doppler frequency with such a profile will generally be bounded by the results for the circular and square beam geometries. The effects of an ideal high-pass filter on the mean Doppler frequency and the backscattered Doppler power are examined. It is shown that such a filter can introduce large differences in the measured systolic to diastolic power ratios. Finally, theoretical expressions and results are presented for the spectral broadening index (SBI), normalized spectral variance (NSV), coefficient of kurtosis (CK), the coefficient of skewness (CS) as functions of the axisymmetric velocity profile shape assuming complete uniform insonation.

  6. Contrast Enhancement Algorithm Based on Gap Adjustment for Histogram Equalization

    PubMed Central

    Chiu, Chung-Cheng; Ting, Chih-Chung

    2016-01-01

    Image enhancement methods have been widely used to improve the visual effects of images. Owing to its simplicity and effectiveness histogram equalization (HE) is one of the methods used for enhancing image contrast. However, HE may result in over-enhancement and feature loss problems that lead to unnatural look and loss of details in the processed images. Researchers have proposed various HE-based methods to solve the over-enhancement problem; however, they have largely ignored the feature loss problem. Therefore, a contrast enhancement algorithm based on gap adjustment for histogram equalization (CegaHE) is proposed. It refers to a visual contrast enhancement algorithm based on histogram equalization (VCEA), which generates visually pleasing enhanced images, and improves the enhancement effects of VCEA. CegaHE adjusts the gaps between two gray values based on the adjustment equation, which takes the properties of human visual perception into consideration, to solve the over-enhancement problem. Besides, it also alleviates the feature loss problem and further enhances the textures in the dark regions of the images to improve the quality of the processed images for human visual perception. Experimental results demonstrate that CegaHE is a reliable method for contrast enhancement and that it significantly outperforms VCEA and other methods. PMID:27338412

  7. Visual Contrast Enhancement Algorithm Based on Histogram Equalization

    PubMed Central

    Ting, Chih-Chung; Wu, Bing-Fei; Chung, Meng-Liang; Chiu, Chung-Cheng; Wu, Ya-Ching

    2015-01-01

    Image enhancement techniques primarily improve the contrast of an image to lend it a better appearance. One of the popular enhancement methods is histogram equalization (HE) because of its simplicity and effectiveness. However, it is rarely applied to consumer electronics products because it can cause excessive contrast enhancement and feature loss problems. These problems make the images processed by HE look unnatural and introduce unwanted artifacts in them. In this study, a visual contrast enhancement algorithm (VCEA) based on HE is proposed. VCEA considers the requirements of the human visual perception in order to address the drawbacks of HE. It effectively solves the excessive contrast enhancement problem by adjusting the spaces between two adjacent gray values of the HE histogram. In addition, VCEA reduces the effects of the feature loss problem by using the obtained spaces. Furthermore, VCEA enhances the detailed textures of an image to generate an enhanced image with better visual quality. Experimental results show that images obtained by applying VCEA have higher contrast and are more suited to human visual perception than those processed by HE and other HE-based methods. PMID:26184219

  8. Integration of Fuzzy and Wavelet Approaches towards Mammogram Contrast Enhancement

    NASA Astrophysics Data System (ADS)

    Khehra, B. S.; Pharwaha, A. P. S.

    2012-06-01

    Mammography is the most reliable, effective, low cost and high sensitive method for early detection of breast cancer. In breast cancer diagnosis, it is difficult for radiologists to detect the typical diagnostic signs because mammograms are low contrast and noisy images. In order to improve diagnosis accuracy, mammogram contrast enhancement technique is often used to enhance the contrast of mammogram and aid the radiologists. In this paper, a combined approach with fuzzy and wavelet towards improved enhancement of details and subtle features in digital mammogram images. The proposed contrast enhancement approach utilizes wavelet transform to decompose the mammogram, and then approximation coefficients are modified by fuzzy contrast enhancement approach and detail coefficients are by non-linear transformation. After that, inverse wavelet transform is applied on modified coefficients to obtain the enhanced mammogram. The proposed algorithm has been tested on a number of images in Digital Database for Screening Mammography (DDSM), comparing the results with histogram equalization which is a well-established image enhancement technique and Cheng's enhancement algorithm based on wavelet transform. In order to accurately assess the proposed approach, enhanced mammogram images are evaluated through objective image quality assessment parameters: information entropy, contrast and peak signal-to-noise ratio (PSNR). Experimental results of the proposed approach are quite promising.

  9. Contrast enhancement via texture region based histogram equalization

    NASA Astrophysics Data System (ADS)

    Singh, Kuldeep; Vishwakarma, Dinesh K.; Singh Walia, Gurjit; Kapoor, Rajiv

    2016-08-01

    This paper presents two novel contrast enhancement approaches using texture regions-based histogram equalization (HE). In HE-based contrast enhancement methods, the enhanced image often contains undesirable artefacts because an excessive number of pixels in the non-textured areas heavily bias the histogram. The novel idea presented in this paper is to suppress the impact of pixels in non-textured areas and to exploit texture features for the computation of histogram in the process of HE. The first algorithm named as Dominant Orientation-based Texture Histogram Equalization (DOTHE), constructs the histogram of the image using only those image patches having dominant orientation. DOTHE categories image patches into smooth, dominant or non-dominant orientation patches by using the image variance and singular value decomposition algorithm and utilizes only dominant orientation patches in the process of HE. The second method termed as Edge-based Texture Histogram Equalization, calculates significant edges in the image and constructs the histogram using the grey levels present in the neighbourhood of edges. The cumulative density function of the histogram formed from texture features is mapped on the entire dynamic range of the input image to produce the contrast-enhanced image. Subjective as well as objective performance assessment of proposed methods is conducted and compared with other existing HE methods. The performance assessment in terms of visual quality, contrast improvement index, entropy and measure of enhancement reveals that the proposed methods outperform the existing HE methods.

  10. Effect of laparoscopic ovarian drilling on vascular endothelial growth factor and ovarian stromal blood flow using 3-dimensional power Doppler.

    PubMed

    El Behery, Manal M; Diab, Abdalla E; Mowafy, Hala; Ebrahiem, Moustafa A; Shehata, Amal E

    2011-02-01

    To determine, by using 3-dimensional power Doppler ultrasonography, the effect of laparoscopic ovarian drilling (LOD) on the serum level of vascular endothelial growth factor (VEGF) and ovarian stromal blood flow changes in polycystic ovary syndrome (PCOS). A prospective controlled clinical study was conducted on 26 clomiphene-resistant women with PCOS who were scheduled for LOD and a control group of 22 fertile regularly menstruating women. VEGF and 3 ovarian Doppler indices-vascularization index, flow index, and vascularization flow index-were measured and compared between the 2 groups, and before and after LOD in the PCOS group. Serum VEGF and the Doppler indices of ovarian stromal blood flow were significantly higher in the PCOS group than in the control group. Serum VEGF and the ovarian stromal blood flow Doppler indices were significantly reduced in the PCOS group after LOD. Increased vascularity in PCOS demonstrated by Doppler blood flow measurements might be explained by the high level of VEGF. LOD reduced ovarian vascularization and serum VEGF. Copyright © 2010 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

  11. Distal aortic intramural hematoma: clinical importance of focal contrast enhancement on CT images.

    PubMed

    Park, Gyung-Min; Ahn, Jung-Min; Kim, Dae-Hee; Kang, Joon-Won; Song, Jong-Min; Kang, Duk-Hyun; Lim, Tae-Hwan; Song, Jae-Kwan

    2011-04-01

    To investigate the prevalence, fate, and effect of focal contrast enhancement lesion within the hematoma on contrast material-enhanced computed tomographic (CT) images in patients with distal aortic intramural hematoma (IMH). This retrospective study was approved by the institutional review board; informed consent was waived. Clinical and CT data in 107 patients with distal IMH who received medical treatment were analyzed, including remodeling processes of IMH at follow-up CT. IMH progression was defined as development of aortic dissection (AD) and aneurysm or hematoma increase. The frequency of focal contrast enhancement was 39.3%, and hematoma was thicker in patients with focal contrast enhancement than in those without (12.3 mm ± 3.6 [standard deviation] vs 10.1 mm ± 4.1, P = .006). Although development of AD occurred more frequently in patients with focal contrast enhancement (21% vs 3%, P = .006), hematoma resorption (57% vs 71%) was the most common pattern of remodeling in both groups without any significant difference (P = .148). The frequency of development of aortic aneurysm (17% vs 14%, P = .690) and increase of hematoma (0% vs 5%, P = .278) was not significantly different between groups. The 1-, 3-, 5-, and 7-year survival rates were 96.3% ± 1.8, 95.2% ± 2.1, 87.9% ± 3.4, and 80.7% ± 4.4, respectively. Patients with IMH progression showed lower survival rates than those without (P = .028). While no significant difference in the overall survival rates could be demonstrated in patients with and those without focal contrast enhancement (P = .442), our study had only 17% power to detect a difference of 10%. Initial maximal aortic diameter was the only factor associated with survival rates (hazard ratio = 1.129; 95% confidence interval: 1.063, 1.199). The optimal cutoff for prediction of mortality within 7 years was 41 mm. Urgent intervention for patients with focal contrast enhancement is not necessary during the acute stage, and long-term close

  12. A high-frequency Doppler feature in the power spectra of simulated GRMHD black hole accretion disks

    SciTech Connect

    Wellons, Sarah; Zhu, Yucong; Narayan, Ramesh; McClintock, Jeffrey E.; Psaltis, Dimitrios

    2014-04-20

    Black hole binaries exhibit a wide range of variability phenomena, from large-scale state changes to broadband noise and quasi-periodic oscillations, but the physical nature of much of this variability is poorly understood. We examine the variability properties of three GRMHD simulations of thin accretion disks around black holes of varying spin, producing light curves and power spectra as would be seen by observers. We find that the simulated power spectra show a broad feature at high frequency, which increases in amplitude with the inclination of the observer. We show that this high-frequency feature is a product of the Doppler effect and that its location is a function of the mass and spin of the black hole. This Doppler feature demonstrates that power spectral properties of the accretion disk can be tied to, and potentially used to determine, physical properties of the black hole.

  13. Value of transrectal power Doppler sonography in the detection of low-risk prostate cancers.

    PubMed

    Sauvain, J-L; Sauvain, E; Rohmer, P; Louis, D; Nader, N; Papavero, R; Bremon, J-M; Jehl, J

    2013-01-01

    To evaluate the risk of low-risk prostate cancer or prostate cancer that may benefit from surveillance in patients with a PSA level less than 10 ng/ml, a normal digital rectal examination (DRE) and a transrectal power Doppler sonography (PDS) without anomaly. Two hundred and forty-three consecutive patients with a PSA level less than 10 ng/ml and a DRE without anomaly had PDS-guided biopsies: 12 to 15 samples were systematically taken and echo-guided in the suspect areas. The PDS results were rated from 1 to 4: 1: normal, 2: slightly hypoechogenic avascular area in which the hypo-echogenicity disappears after compression by probe, 3: hypoechogenic avascular area, 4: hypoechogenic vascularised area with power Doppler sonography. Patients rated 3 or 4 were considered to be pathological. D'Amico's criteria were used to assess the risk of a biological recurrence after treatment and those of Dall'Era were used to select the patients that could benefit from active surveillance (AS). The PDS was considered to be a true positive if at least one biopsy was positive in the same sextant as the suspect image. In a prospective manner, 106 cancers were diagnosed that could be qualified as low-risk in 84% of the cases (89% with a normal PDS and 79% with an abnormal PDS). Sixty-nine percent of the cases could be subject to AS (86% of the normal PDS cases and 47% of the abnormal PDS cases; P<0.001). The PDS was normal in 159 of the 243 patients (65%). With a normal PDS, there was a 96% probability of not having a high-risk cancer. With an abnormal PDS, at least one biopsy was positive in 57% of the cases and the probability of having a significant cancer was 30% according to the Dall'Era criteria. A significant reduction was noted with a normal PDS, to 36% and 5%, respectively (VPN=95%) (P=0.015). A normal PDS in patients presenting a PSA level less than 10 ng/ml and a DRE without anomaly may be used to put off the indication for a biopsy in order to reduce their number as well as

  14. Measurement of the Stopping Power of Water for Carbon Ions Using Inverted Doppler Shift Attenuation

    SciTech Connect

    Rahm, J.M.; Baek, W.Y.; Rabus, H.; Hofsaess, H.

    2015-07-01

    Carbon ion therapy has gained importance in cancer treatment due to its locally well confined dose distribution, but there is a significant lack of experimental data which is needed for dose calculations and estimation of biological damage. Since tissue is mainly comprised of water, the energy-dependent stopping power of water is the critical measure. Importantly, previous data gathered from experiments with light ions has been limited to water vapour and ice and neglected water in its liquid phase. Additionally, theoretical models regarding the stopping power cannot yet describe the complex charge transfer interactions of the projectile at velocities in the range of the mean velocity of the valence electrons of the traversed medium. There are also discrepancies in the amount of phase effects concerning water and water vapour cross sections. Despite its importance there exists no experimental data for the stopping power of water for carbon ions in the energy region between 1 MeV and 5 MeV. This may be due to the short track length of carbon ions which makes traditional transmission experiments unfeasible. Therefore a project was launched to measure the stopping power of liquid water for carbon ions in the vicinity of the Bragg peak which corresponds to the energy regime of the maximum stopping power. For this measurement the inverted Doppler shift attenuation method was used. This uses the gamma quanta emitted from excited carbon nuclei which are produced by means of the {sup 12}C(α,α'){sup 12}C* reaction. The recorded γ-spectra contain the information of the projectiles velocity at the time they decay to their ground state and an internal clock provided by the exponential decay law. The deceleration of the projectile is directly connected to the stopping power which can be determined with this method as a function of the projectiles kinetic energy. Further measurements have been carried out to improve the experimental method. The setup and the preliminary

  15. Accurate evaluation of axillary sentinel lymph node metastasis using contrast-enhanced ultrasonography with Sonazoid in breast cancer: a preliminary clinical trial.

    PubMed

    Matsuzawa, Fumihiko; Omoto, Kiyoka; Einama, Takahiro; Abe, Hironori; Suzuki, Takashi; Hamaguchi, Jun; Kaga, Terumi; Sato, Mami; Oomura, Masako; Takata, Yumiko; Fujibe, Ayako; Takeda, Chie; Tamura, Etsuya; Taketomi, Akinobu; Kyuno, Kenichi

    2015-01-01

    Breast cancer is the most common type of cancer in women. The 5-year survival rate in patients with breast cancer ranges from 74 to 82 %. Sentinel lymph node biopsy has become an alternative to axillary lymph node dissection for nodal staging. We evaluated the detection of the sentinel lymph node and metastasis of the lymph node using contrast enhanced ultrasonography with Sonazoid. Between December 2013 and May 2014, 32 patients with operable breast cancer were enrolled in this study. We evaluated the detection of axillary sentinel lymph nodes and the evaluation of axillary lymph nodes metastasis using contrast enhanced computed tomography, color Doppler ultrasonography and contrast enhanced ultrasonography with Sonazoid. All the sentinel lymph nodes were identified, and the sentinel lymph nodes detected by contrast enhanced ultrasonography with Sonazoid corresponded with those detected by computed tomography lymphography and indigo carmine method. The detection of metastasis based on contrast enhanced computed tomography were sensitivity 20.0 %, specificity 88.2 %, PPV 60.0 %, NPV 55.6 %, accuracy 56.3 %. Based on color Doppler ultrasonography, the results were sensitivity 36.4 %, specificity 95.2 %, PPV 80.0 %, NPV 74.1 %, accuracy 75.0 %. Based on contrast enhanced ultrasonography with Sonazoid, the results were sensitivity 81.8 %, specificity 95.2 %, PPV 90.0 %, NPV 90.9 %, accuracy 90.6 %. The results suggested that contrast enhanced ultrasonography with Sonazoid was the most accurate among the evaluations of these modalities. In the future, we believe that our method would take the place of conventional sentinel lymph node biopsy for an axillary staging method.

  16. Limitations of three-dimensional power Doppler angiography in preoperative evaluation of ovarian tumors.

    PubMed

    Silvestre, Liliane; Martins, Wellington P; Candido-Dos-Reis, Francisco J

    2015-07-29

    This study describes the accuracy of three-dimensional power Doppler (3D-PD) angiography as secondary method for differential diagnosis of ovarian tumors. Seventy-five women scheduled for surgical removal of adnexal masses were assessed by transvaginal ultrasound. Ovarian tumors were classified by IOTA simple rules and two three-dimensional blocks were recorded. In a second step analyses, a 4 cm(3) spherical sample was obtained from the highest vascularized solid area of each stored block. Vascularization index (VI), flow index (FI) and vascularization-flow index (VFI) were calculated. The repeatability was assessed by concordance correlation coefficient (CCC) and limits of agreement (LoA), and diagnostic accuracy by area under ROC curve. IOTA simple rules classified 26 cases as benign, nine as inconclusive and 40 as malignant. There were eight false positive and no false negative. Among the masses classified as inconclusive or malignant by IOTA simple rules, the CCCs were 0.91 for VI, 0.70 for FI, and 0.86 for VFI. The areas under ROC curve were 0.82 for VI, 0.67 for FI and 0.81 for VFI. 3D-PD angiography presented considerable intraobserver variability and low accuracy for identifying false positive results of IOTA simple rules.

  17. Power Doppler ultrasonography in the evaluation of infliximab treatment for sacroiliitis in patients with ankylosing spondylitis.

    PubMed

    Jiang, Yeqing; Chen, Ling; Zhu, Jiaan; Xue, Qin; Wang, Niansong; Huang, Yunxia; Liu, Fang; Hu, Yizhou; Hu, Bing

    2013-08-01

    The aim of this study was to evaluate the feasibility of using power Doppler ultrasound (PDUS) to detect changes in the sacroiliac joint regions after infliximab (an anti-TNF-α blocker) treatment in active axial ankylosing spondylitis (AS) patients. A total of 110 sacroiliac joints in 55 patients with active AS were detected by PDUS before and after the infliximab treatment. The color flow signals inside the sacroiliac joints were observed, and the resistance index (RI) was measured. The clinical condition of the AS patients was improved compared with their condition before the infliximab treatment. Before the treatment, color flow signals were observed in 103 joints, and the mean RI value was 0.56 ± 0.06. Three months after the first infliximab treatment, color flow signals were observed in 50 joints, and the mean RI value was 0.87 ± 0.11. There were more blood flow signals in the sacroiliac joints before the infliximab treatment in patients with active AS (p < 0.01), and the mean RI value was higher after the infliximab treatment (p < 0.01). The blood flow signals in the sacroiliac joints became weaker or even disappeared and the RI values increased in patients with active sacroiliitis after infliximab treatment. This result shows that PDUS can be used in the follow-up of patients with axial AS.

  18. Time-resolved measurement of bubble cavitation by using power Doppler ultrasound image

    NASA Astrophysics Data System (ADS)

    Koda, Ren; Izumi, Yosuke; Nagai, Hayato; Yamakoshi, Yoshiki

    2017-04-01

    In this study, a novel measurement method for a secondary ultrasound wave irradiated by microbubble cavitation is proposed. High-intensity ultrasound (h-US, 1.0-1.5 MPa), which produces bubble cavitation, is irradiated with a fixed time delay after introducing imaging US, whose frequency is different from that of the h-US. The bubble cavitation signal (BCS) is detected by the signal-processing unit of an ultrasound power Doppler imaging instrument. By this method, both a spatially resolved bubble image (S-image) and the temporal transition of the BCS (T-image) are monitored simultaneously. A feature of the method is that the BCS is observed in situ with sub-µs time resolution. The accuracy of the method is evaluated and it is found that the maximum deviation of the amplitude of the simulated BCS is 4.80%. This method is applied to measure the BCS of ultrasound contrast agent microbubbles. As a result, the dependence of the inherent temporal transition of the BCS on the sound pressure of the h-US (0.6-1.2 MPa) is observed.

  19. Medial tibial pain: a dynamic contrast-enhanced MRI study.

    PubMed

    Mattila, K T; Komu, M E; Dahlström, S; Koskinen, S K; Heikkilä, J

    1999-09-01

    The purpose of this study was to compare the sensitivity of different magnetic resonance imaging (MRI) sequences to depict periosteal edema in patients with medial tibial pain. Additionally, we evaluated the ability of dynamic contrast-enhanced imaging (DCES) to depict possible temporal alterations in muscular perfusion within compartments of the leg. Fifteen patients with medial tibial pain were examined with MRI. T1-, T2-weighted, proton density axial images and dynamic and static phase post-contrast images were compared in ability to depict periosteal edema. STIR was used in seven cases to depict bone marrow edema. Images were analyzed to detect signs of compartment edema. Region-of-interest measurements in compartments were performed during DCES and compared with controls. In detecting periosteal edema, post-contrast T1-weighted images were better than spin echo T2-weighted and proton density images or STIR images, but STIR depicted the bone marrow edema best. DCES best demonstrated the gradually enhancing periostitis. Four subjects with severe periosteal edema had visually detectable pathologic enhancement during DCES in the deep posterior compartment of the leg. Percentage enhancement in the deep posterior compartment of the leg was greater in patients than in controls. The fast enhancement phase in the deep posterior compartment began slightly slower in patients than in controls, but it continued longer. We believe that periosteal edema in bone stress reaction can cause impairment of venous flow in the deep posterior compartment. MRI can depict both these conditions. In patients with medial tibial pain, MR imaging protocol should include axial STIR images (to depict bone pathology) with T1-weighted axial pre and post-contrast images, and dynamic contrast enhanced imaging to show periosteal edema and abnormal contrast enhancement within a compartment.

  20. Using Dynamic Contrast Enhanced MRI to Quantitatively Characterize Maternal Vascular Organization in the Primate Placenta

    PubMed Central

    Frias, A.E.; Schabel, M.C.; Roberts, V.H.J.; Tudorica, A.; Grigsby, P.L.; Oh, K.Y.; Kroenke, C. D.

    2015-01-01

    Purpose The maternal microvasculature of the primate placenta is organized into 10-20 perfusion domains that are functionally optimized to facilitate nutrient exchange to support fetal growth. This study describes a dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) method for identifying vascular domains, and quantifying maternal blood flow in them. Methods A rhesus macaque on the 133rd day of pregnancy (G133, term=165 days) underwent Doppler ultrasound (US) procedures, DCE-MRI, and Cesarean-section delivery. Serial T1-weighted images acquired throughout intravenous injection of a contrast reagent (CR) bolus were analyzed to obtain CR arrival time maps of the placenta. Results Watershed segmentation of the arrival time map identified 16 perfusion domains. The number and location of these domains corresponded to anatomical cotyledonary units observed following delivery. Analysis of the CR wave front through each perfusion domain enabled determination of volumetric flow, which ranged from 9.03 to 44.9 mL/sec (25.2 ± 10.3 mL/sec). These estimates are supported by Doppler US results. Conclusions The DCE-MRI analysis described here provides quantitative estimates of the number of maternal perfusion domains in a primate placenta, and estimates flow within each domain. Anticipated extensions of this technique are to the study placental function in nonhuman primate models of obstetric complications. PMID:24753177

  1. How to Develop a Contrast-Enhanced Ultrasound Program.

    PubMed

    Barr, Richard G

    2017-02-02

    With the recent Food and Drug Administration approval of Lumason (sulfur hexafluoride lipid-type A microsphere, Bracco Diagnostics Inc, Monroe Township, NJ) for contrast-enhanced ultrasound (CEUS) to characterize focal liver lesions in both adult and pediatric patients, widespread use of CEUS is expected in the United States. This paper provides guidance in setting up a CEUS program, and reviews the practical details that will need to be instituted in a standard ultrasound department to provide both safe and efficient use of CEUS. A review of the indications, contraindications, adverse events, instructions for performing the exam, and image interpretation are discussed.

  2. Neovascularity in patellar tendinopathy and the response to eccentric training: a case report using Power Doppler ultrasound.

    PubMed

    McCreesh, Karen M; Riley, Sara J; Crotty, James M

    2013-12-01

    This report describes the case of an amateur soccer player with chronic patellar tendinopathy who underwent ultrasound imaging before and after engaging in an 8-week programme of eccentric exercise. On initial assessment, greyscale ultrasound imaging demonstrated tendon thickening and reduced echogenicity, while Power Doppler imaging demonstrated a large amount of neovascularity. After 8 weeks of an eccentric loading programme, the patient reported significantly improved symptoms and functional scores, while follow-up imaging demonstrated improvement in the echo appearance of the tendon and complete resolution of the neovascularity. The association between neovascularity and symptoms in tendinopathy research is conflicting, with a paucity of research in the area of patellar tendinopathy. While further research is needed to clarify the significance of greyscale and Power Doppler ultrasound changes in relation to symptoms in patellar tendinopathy, ultrasound imaging was shown to be a useful adjunct to diagnosis and outcome assessment in this case.

  3. Adaptive sigmoid function bihistogram equalization for image contrast enhancement

    NASA Astrophysics Data System (ADS)

    Arriaga-Garcia, Edgar F.; Sanchez-Yanez, Raul E.; Ruiz-Pinales, Jose; Garcia-Hernandez, Ma. de Guadalupe

    2015-09-01

    Contrast enhancement plays a key role in a wide range of applications including consumer electronic applications, such as video surveillance, digital cameras, and televisions. The main goal of contrast enhancement is to increase the quality of images. However, most state-of-the-art methods induce different types of distortion such as intensity shift, wash-out, noise, intensity burn-out, and intensity saturation. In addition, in consumer electronics, simple and fast methods are required in order to be implemented in real time. A bihistogram equalization method based on adaptive sigmoid functions is proposed. It consists of splitting the image histogram into two parts that are equalized independently by using adaptive sigmoid functions. In order to preserve the mean brightness of the input image, the parameter of the sigmoid functions is chosen to minimize the absolute mean brightness metric. Experiments on the Berkeley database have shown that the proposed method improves the quality of images and preserves their mean brightness. An application to improve the colorfulness of images is also presented.

  4. Fuzzy pulmonary vessel segmentation in contrast enhanced CT data

    NASA Astrophysics Data System (ADS)

    Kaftan, Jens N.; Kiraly, Atilla P.; Bakai, Annemarie; Das, Marco; Novak, Carol L.; Aach, Til

    2008-03-01

    Pulmonary vascular tree segmentation has numerous applications in medical imaging and computer-aided diagnosis (CAD), including detection and visualization of pulmonary emboli (PE), improved lung nodule detection, and quantitative vessel analysis. We present a novel approach to pulmonary vessel segmentation based on a fuzzy segmentation concept, combining the strengths of both threshold and seed point based methods. The lungs of the original image are first segmented and a threshold-based approach identifies core vessel components with a high specificity. These components are then used to automatically identify reliable seed points for a fuzzy seed point based segmentation method, namely fuzzy connectedness. The output of the method consists of the probability of each voxel belonging to the vascular tree. Hence, our method provides the possibility to adjust the sensitivity/specificity of the segmentation result a posteriori according to application-specific requirements, through definition of a minimum vessel-probability required to classify a voxel as belonging to the vascular tree. The method has been evaluated on contrast-enhanced thoracic CT scans from clinical PE cases and demonstrates overall promising results. For quantitative validation we compare the segmentation results to randomly selected, semi-automatically segmented sub-volumes and present the resulting receiver operating characteristic (ROC) curves. Although we focus on contrast enhanced chest CT data, the method can be generalized to other regions of the body as well as to different imaging modalities.

  5. Contrast enhanced imaging with a stationary digital breast tomosynthesis system

    NASA Astrophysics Data System (ADS)

    Puett, Connor; Calliste, Jabari; Wu, Gongting; Inscoe, Christina R.; Lee, Yueh Z.; Zhou, Otto; Lu, Jianping

    2017-03-01

    Digital breast tomosynthesis (DBT) captures some depth information and thereby improves the conspicuity of breast lesions, compared to standard mammography. Using contrast during DBT may also help distinguish malignant from benign sites. However, adequate visualization of the low iodine signal requires a subtraction step to remove background signal and increase lesion contrast. Additionally, attention to factors that limit contrast, including scatter, noise, and artifact, are important during the image acquisition and post-acquisition processing steps. Stationary DBT (sDBT) is an emerging technology that offers a higher spatial and temporal resolution than conventional DBT. This phantom-based study explored contrast-enhanced sDBT (CE sDBT) across a range of clinically-appropriate iodine concentrations, lesion sizes, and breast thicknesses. The protocol included an effective scatter correction method and an iterative reconstruction technique that is unique to the sDBT system. The study demonstrated the ability of this CE sDBT system to collect projection images adequate for both temporal subtraction (TS) and dual-energy subtraction (DES). Additionally, the reconstruction approach preserved the improved contrast-to-noise ratio (CNR) achieved in the subtraction step. Finally, scatter correction increased the iodine signal and CNR of iodine-containing regions in projection views and reconstructed image slices during both TS and DES. These findings support the ongoing study of sDBT as a potentially useful tool for contrast-enhanced breast imaging and also highlight the significant effect that scatter has on image quality during DBT.

  6. Contrast-enhanced magnetic resonance imaging of hypoperfused myocardium.

    PubMed

    Schaefer, S; Lange, R A; Gutekunst, D P; Parkey, R W; Willerson, J T; Peshock, R M

    1991-06-01

    Contrast-enhanced magnetic resonance (MR) imaging can define myocardial perfusion defects due to acute coronary occlusion. However, since most clinically important diagnostic examinations involve coronary arteries with subtotal stenoses, we investigated the ability of MR imaging with a manganese contrast agent to detect perfusion abnormalities in a canine model of partial coronary artery stenosis. The contrast agent was administered after the creation of a partial coronary artery stenosis with the addition of the coronary vasodilator dipyridamole in six of 12 animals. The hearts were imaged ex situ using gradient reversal and spin-echo sequences, and images were analyzed to determine differences in signal intensity between hypoperfused and normally perfused myocardium. Comparison of MR images with regional blood flow and thallium-201 measurements showed good concordance of hypoperfused segments in those animals given dipyridamole, with 75% of the abnormal segments correctly identified. In those animals not given dipyridamole, 48% of segments were correctly identified. Thus, ex vivo MR imaging with a paramagnetic contrast enhancement can be used to detect acute regional myocardial perfusion abnormalities due to severe partial coronary artery stenoses.

  7. Contrast-enhanced harmonic endoscopic ultrasonography for assessment of lymph node metastases in pancreatobiliary carcinoma

    PubMed Central

    Miyata, Takeshi; Kitano, Masayuki; Omoto, Shunsuke; Kadosaka, Kumpei; Kamata, Ken; Imai, Hajime; Sakamoto, Hiroki; Nisida, Naoshi; Harwani, Yogesh; Murakami, Takamichi; Takeyama, Yoshifumi; Chiba, Yasutaka; Kudo, Masatoshi

    2016-01-01

    AIM: To assess the usefulness of contrast-enhanced harmonic endoscopic ultrasonography (CH-EUS) for lymph node metastasis in pancreatobiliary carcinoma. METHODS: All patients suspected of pancreatobiliary carcinoma with visible lymph nodes after standard EUS between June, 2009 and January, 2012 were enrolled. In the primary analysis, patients with successful EUS-fine needle aspiration (FNA) were included. The lymph nodes were assessed by several standard EUS variables (short and long axis lengths, shape, edge characteristic and echogenicity), color Doppler EUS variable [central intranodal blood vessel (CIV) presence] and CH-EUS variable (heterogeneous/homogeneous enhancement patterns). The diagnostic accuracy relative to EUS-FNA was calculated. In the second analysis, N-stage diagnostic accuracy of CH-EUS was compared with EUS-FNA in patients who underwent surgical resection. RESULTS: One hundred and nine patients (143 lymph nodes) fulfilled the criteria. The short axis cut-off ≥ 13 mm predicted malignancy with a sensitivity and specificity of 72% and 85%, respectively. These values were 72% and 63% for the long axis cut-off ≥ 20 mm, 62% and 75% for the round shape variable, 81% and 30% for the sharp edge variable, 66% and 61% for the hypoechogenicity variable, 70% and 72% for the CIV-absent variable, and 83% and 91% for the heterogeneous CH-EUS-enhancement variable, respectively. CH-EUS was more accurate than standard and color Doppler EUS, except the short axis cut-off. Notably, three patients excluded because of EUS-FNA failure were correctly N-staged by CH-EUS. CONCLUSION: CH-EUS complements standard and color Doppler EUS and EUS-FNA for assessment of lymph node metastases. PMID:27022220

  8. Echocolor Power Doppler with contrast medium to evaluate vascularization in lesions of the soft tissues of the limbs.

    PubMed

    De Marchi, A; De Petro, P; Faletti, C; Brach del Prever, E M; Gino, G; Albertini, U; Piana, R; Marone, S; Mellano, D; Linari, A; Forni, M; Bertoldo, U; Comandone, A; Boglione, A; Brach del Prever, A

    2003-01-01

    Echocolor Power Doppler with contrast medium forms a non-invasive vascular image; the purpose of the study is to evaluate the effectiveness in differentiating benign and malignant tumors in the soft tissues of the limbs. Echocolor Power Doppler with contrast medium was used to study 80 patients with swelling in the soft tissues of the limbs: there were 54 benign lesions, 22 sarcomas, and 4 aggressive desmoid fibromatoses. Were identified 4 patterns of wash-in and wash-out curves that could be correlated to the histological diagnosis: type I was present in 85% of benign lesions, type III in 91% of malignant lesions and in 3.7% of the benign ones, type II in aggressive fibromatoses, anomalous type in 4 benign lesions and 2 sarcomas; the curve was absent in 2 benign lesions. Power Doppler Echocolor with contrast medium can become a useful method to be associated with traditional imaging methods in the differential diagnosis of swelling of the soft tissues of the limbs.

  9. Focal Liver Lesions: Real-time 3-Dimensional Contrast-Enhanced Ultrasonography Compared With 2-Dimensional Contrast-Enhanced Ultrasonography and Magnetic Resonance Imaging.

    PubMed

    Lee, Jung-Chieh; Yan, Kun; Lee, San-Kan; Yang, Wei; Chen, Min-Hua

    2017-06-24

    This study sought to evaluate the application of real-time 3-dimensional (3D) contrast-enhanced ultrasonography (US) to diagnose focal liver lesions and to compare these results with those from 2-dimensional (2D) contrast-enhanced US and contrast-enhanced magnetic resonance imaging (MRI). Patients with focal liver lesions were examined by 2D contrast-enhanced US, 3D contrast-enhanced US, and contrast-enhanced MRI for lesion characterization, and biopsies and comprehensive clinical diagnoses served as reference standards. The sensitivity, specificity, area under the receiver operating characteristic curve, and intermodality agreement were assessed. The number of contrast agent injections and lesions observed per injection were calculated for 3D and 2D contrast-enhanced US. The number and display quality of the feeding arteries observed with 3D and 2D contrast-enhanced US were assessed. A total of 117 patients with 151 focal liver lesions were enrolled, including 67 cases of hepatocellular carcinoma, 51 cases of liver metastasis, and 33 cases of benign liver lesions. No significant differences were found among the modalities. The sensitivity values for 3D contrast-enhanced US, 2D contrast-enhanced US, and contrast-enhanced MRI were 96%, 95%, and 93%, respectively; the specificity values were 87%, 84%, and 89%; and the area under the receiver operating characteristic curve values were 0.92, 0.90, and 0.92. The intermodality agreement was excellent (κ > 0.77). Fewer contrast agent injections were needed, and more lesions and feeding arteries were more clearly displayed on 3D than 2D contrast-enhanced US (P < .001). Real-time 3D contrast-enhanced US is useful for diagnosing focal liver lesions and for observing feeding arteries with fewer contrast agent injections. © 2017 by the American Institute of Ultrasound in Medicine.

  10. Comparison of dynamic contrast-enhanced MR, ultrasound and optical imaging modalities to evaluate the antiangiogenic effect of PF-03084014 and sunitinib

    PubMed Central

    Zhang, Cathy C; Yan, Zhengming; Giddabasappa, Anand; Lappin, Patrick B; Painter, Cory L; Zhang, Qin; Li, Gang; Goodman, James; Simmons, Brett; Pascual, Bernadette; Lee, Joseph; Levkoff, Ted; Nichols, Tim; Xie, Zhiyong

    2014-01-01

    Noninvasive imaging has been widely applied for monitoring antiangiogenesis therapy in cancer drug discovery. In this report, we used different imaging modalities including high-frequency ultrasound (HFUS), dynamic contrast enhanced-MR (DCE-MR), and fluorescence molecular tomography (FMT) imaging systems to monitor the changes in the tumor vascular properties after treatment with γ-secretase inhibitor PF-03084014. Sunitinib was tested in parallel for comparison. In the MDA-MB-231Luc model, we demonstrated that antiangiogenesis was one of the contributing mechanisms for the therapeutic effect of PF-03084014. By immunohistochemistry and FITC-lectin perfusion assays, we showed that the vascular defects upon treatment with PF-03084014 were associated with Notch pathway modulation, evidenced by a decrease in the HES1 protein and by the changes in VEGFR2 and HIF1α levels, which indicates down-stream effects. Using a 3D power Doppler scanning method, ultrasound imaging showed that the% vascularity in the MDA-MB-231Luc tumor decreased significantly at 4 and 7 days after the treatment with PF-03084014. A decrease in the tumor vessel function was also observed through contrast-enhanced ultrasound imaging with microbubble injection. These findings were consistent with the PF-03084014-induced functional vessel changes measured by suppressing the Ktrans values using DCE-MRI. In contrast, the FMT imaging with the AngioSence 680EX failed to detect any treatment-associated tumor vascular changes. Sunitinib demonstrated an outcome similar to PF-03084014 in the tested imaging modalities. In summary, ultrasound and DCE-MR imaging successfully provided longitudinal measurement of the phenotypic and functional changes in tumor vasculature after treatment with PF-03084014 and sunitinib. PMID:24573979

  11. Staging of Macular Telangiectasia: Power-Doppler Optical Coherence Tomography and Macular Pigment Optical Density

    PubMed Central

    Chin, Eric K.; Kim, Dae Yu; Hunter, Allan A.; Pilli, Suman; Wilson, Machelle; Zawadzki, Robert J.; Werner, John S.; Park, Susanna S.

    2013-01-01

    Purpose. Two methods were used to study the stages of macular telangiectasia (MacTel): Power-Doppler optical coherence tomography (PD-OCT), which allows imaging of the retinal circulation in three dimensions, and macular pigment optical density (MPOD), which quantifies the distribution of macular carotenoids. Methods. Among 49 patients with MacTel identified, 12 eyes (6 patients) with MacTel and 7 age-matched control eyes (7 patients) were imaged with a custom-built Fourier-domain OCT instrument to acquire PD-OCT images. MPOD was measured using heterochromatic flicker photometry in 10 eyes (5 patients) with MacTel and compared with 44 age-matched control eyes (44 patients). Clinical staging of MacTel was based on best-corrected visual acuity, fundus biomicroscopy, fluorescein angiography, and OCT. Results. Stage 1 eyes (n = 2) had subtle punctate vascular signal confined to the inner portion of the outer plexiform layer (OPL) on PD-OCT. Stage 2 (n = 2) showed larger oblique vascular signal extending into deeper OPL. Stage 3 (n = 5) had disruption of outer retinal layers with abnormal vasculature extending into the outer nuclear layer. Stage 4 (n = 3) showed diffuse blurring of the retinal layers with vascular channels extending the full thickness of the retina. MPOD values in four eyes with stage 1 or 2 MacTel correlated well with age-matched controls. Six eyes with stage 3 or 4 MacTel had loss of MPOD especially at the fovea. Conclusions. PD-OCT shows penetration of the retinal capillaries into the deeper retinal layers in early stages of MacTel, with full thickness vascular proliferation in advanced disease. MPOD is commonly depleted but may appear normal in early stage MacTel. PMID:23716628

  12. Anti-CCP status determines the power Doppler oscillation pattern in rheumatoid arthritis: a prospective study.

    PubMed

    Gadeholt, Ottar; Wech, Tobias; Schuh, Sebastian; Scharbatke, Eva; Ostermeier, Eva; Tony, Hans-Peter; Schmalzing, Marc

    2016-12-01

    Rheumatoid arthritis (RA) is a chronic inflammatory disease leading to joint destruction. Serologically, it can be differentiated according to rheumatoid factor (RF), anti-cyclic citrullinated peptide antibodies (anti-CCP), or both. This differentiation is prognostically and therapeutically relevant. No method has been described to separate the two forms phenotypically. We hypothesize that a differentiation is possible by evaluating oscillation patterns in power Doppler sonography (PDS). In a prospective study, 20 patients with anti-CCP-positive RA and 20 patients with anti-CCP-negative RA with active wrist synovitis were examined. A PDS scan was performed, and perfusion maxima (P max) and minima (P min) as well as the amplitude (ΔP) were determined by a blinded study member. The amplitude was standardized (sΔP) by dividing by P max, and the anti-CCP-positive and anti-CCP-negative patients as well as the RF-positive and RF-negative were compared to each other. In the ultrasonographic evaluation, we found a highly significant difference in sΔP between CCPp and CCPn patients (median 19.0 vs. 42.9 %, p < 0.0001). sΔP is independent of disease activity. The absolute amplitude ΔP did not differ between the groups. Also, in anti-CCP-positive patients there was a completely linear correlation between P max and P min, and this was far less marked in anti-CCP-negative patients. Anti-CCP-positive and anti-CCP-negative RA display different PDS oscillation patterns. This constitutes a nonserological parameter to differentiate between the two forms. The difference in PDS oscillation patterns suggests that the underlying pathological process differs between the forms.

  13. Three-dimensional power Doppler ultrasound in cervical carcinoma: monitoring treatment response to radiotherapy.

    PubMed

    Huang, Y-F; Cheng, Y-M; Wu, Y-P; Chen, H H W; Hsu, K-F; Wu, Y-H; Chou, C-Y

    2013-07-01

    To investigate, using three-dimensional power Doppler ultrasound (3D-PDU), alterations in cervical intratumoral vascularization during and after radiotherapy. Between 2004 and 2009 we enrolled into the study 37 patients with FIGO Stages IB1-IIB cervical carcinoma who were undergoing radiotherapy. Serial 3D-PDU scans were performed during treatment, providing ultrasonographic measurement of tumor size, vascularization index, flow index and vascularization flow index, as well as monthly for 3 months post-treatment and tri-monthly thereafter, until vascularity was undetectable on two consecutive occasions. Physical examination, cervical cytology and serum marker evaluation were performed every 3-6 months for the first 5 years following treatment. Patients evaluated after a 2-year tumor-free interval and those with clinically assessed positive findings at follow-up underwent 3D-PDU to detect possible local disease. A total of 329 3D-PDU scans were performed in the 37 women. Cervical tumors and intratumoral vascularization disappeared within 3 months following radiotherapy, except in one patient with persistent disease. Nine patients had disease relapse, in four of whom the recurrence was local. In three of these four, there was recurrence of tumor and vascularization after a complete response. At follow-up, 3D-PDU detected local disease with 75.0% sensitivity and 98.5% specificity, while serum markers detected local disease among 34 patients with squamous cell carcinoma with 20.0% sensitivity and 77.3% specificity. Compared with serum markers in cervical squamous cell carcinoma, 3D-PDU has higher sensitivity and specificity for detecting local recurrence or persistence in cervical carcinoma. Thus, 3D-PDU combined with clinical assessment may be a new and safe method for monitoring radiotherapy treatment response and detecting local recurrence. Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.

  14. Arthrofibrosis associated with total knee arthroplasty: gray-scale and power Doppler sonographic findings.

    PubMed

    Boldt, Jens G; Munzinger, Urs K; Zanetti, Marco; Hodler, Juerg

    2004-02-01

    The objective of this study was to determine gray-scale and power Doppler sonographic findings in patients with arthrofibrosis associated with total knee arthroplasty. SUBJECTS AND METHODS. From a consecutive cohort of more than 3000 mobilebearing total knee arthroplasties, 44 cases (1.5%) with arthrofibrosis were identified, of which 38 were recruited for a clinical and sonographic investigation. A control group of 38 patients with a well-functioning total knee arthroplasty was matched. Synovial hypertrophy, presence of neovascularity, patellar tendon thickness, and extent of effusion were assessed. Synovial membrane thickness was significantly (p < 0.001) increased in the arthrofibrosis group (medial, 3.4 mm; lateral, 3.0 mm; suprapatellar, 3.1 mm) when compared with the control group (medial, 2.0 mm; lateral, 2.0 mm; suprapatellar, 1.9 mm). When a cutoff of 3.0 mm was used, sonography had a sensitivity of 84% and a specificity of 82% for detecting arthrofibrosis. Neovascularity (rated as grades 0-3) of the synovial membrane and Hoffa's fat pad was significantly (p

  15. The usefulness of power Doppler ultrasonography in differentiating primary and secondary Raynaud's phenomenon.

    PubMed

    Lee, Sang Il; Lee, Sang Yong; Yoo, Wan Hee

    2006-11-01

    The objectives of this study were to assess a usefulness of power Doppler ultrasonography (PDU) and compare the diagnostic value of PDU to nailfold capillaroscopy (NFC) in the patients with clinically diagnosed Raynaud's phenomenon (RP) and healthy controls. Forty-one patients with primary (n=19), secondary RP (n=22), and ten healthy controls underwent PDU and NFC examinations on the same day. Microvascularity was evaluated using PDU before and after cold challenges, and the PDU signals were qualitatively graded on a scale of 1-4. According to the change of microvascularity before and after cold challenges, the findings of PDU were classified into three groups: (1) 'pattern I' (normal microvascularity over grade 3 both before and after cold challenges), (2) 'pattern II' (decreased microvascularity to grade 1 or 2 only after cold challenge), and (3) 'pattern III' (decreased microvascularity of grade 1 or 2 both before and after cold challenges). PDU confirmed the presence of RP in all patients with clinically diagnosed RP and yielded a correct classification in 88.9% of the all persons analyzed (normal=100%, primary RP=89.5%, secondary RP=77.3%). The analysis was performed to assess the degree of agreement between the final diagnoses obtained by PDU and NFC. A good correlation rate was observed between PDU and NFC examinations in differentiating primary from secondary RP (Kappa=0.658, p<0.01). In conclusion, PDU examination with a cold challenge is a useful and reliable method to diagnose RP and discriminate between primary and secondary RP.

  16. [Management of salivary gland diseases with contrast-enhanced ultrasound].

    PubMed

    Zengel, P; Schrötzlmair, F; Kramer, M; Paprottka, P; Clevert, D-A

    2011-06-01

    Obstructive diseases of the salivary glands are a common problem in otorhinolaryngology. They are mostly due to sialolithiasis followed by duct stenosis and other rarer causes. Several diagnostic modalities exist which allow classification of the disease; however, in 5-10% of all cases ultrasound and conventional radiological imaging do not provide a clear diagnosis. Ultrasound examination with contrast material injected into the duct (IA-CEUS, intraductal administered contrast-enhanced ultrasound) enables improved evaluation of obstructive diseases of the salivary glands and at the same time an evaluation of the parenchyma of the glands is possible. As a complementary method to conventional investigation techniques IA-CEUS is an economic and rapid method with low side-effects which improves the diagnostic assessment of ultrasound and results in a better treatment for patients.

  17. Contrast enhancing solution for use in confocal microscopy

    DOEpatents

    Tannous, Zeina; Torres, Abel; Gonzalez, Salvador

    2006-10-31

    A method of optically detecting a tumor during surgery. The method includes imaging at least one test point defined on the tumor using a first optical imaging system to provide a first tumor image. The method further includes excising a first predetermined layer of the tumor for forming an in-vivo defect area. A predetermined contrast enhancing solution is disposed on the in-vivo defect area, which is adapted to interact with at least one cell anomaly, such as basal cell carcinoma, located on the in-vivo defect area for optically enhancing the cell anomaly. Thereafter the defect area can be optically imaged to provide a clear and bright representation of the cell anomaly to aid a surgeon while surgically removing the cell anomaly.

  18. Contrast-enhanced imaging of cerebral vasculature with laser speckle

    NASA Astrophysics Data System (ADS)

    Murari, K.; Li, N.; Rege, A.; Jia, X.; All, A.; Thakor, N.

    2007-08-01

    High-resolution cerebral vasculature imaging has applications ranging from intraoperative procedures to basic neuroscience research. Laser speckle, with spatial contrast processing, has recently been used to map cerebral blood flow. We present an application of the technique using temporal contrast processing to image cerebral vascular structures with a field of view a few millimeters across and approximately 20 μm resolution through a thinned skull. We validate the images using fluorescent imaging and demonstrate a factor of 2-4 enhancement in contrast-to-noise ratios over reflectance imaging using white or spectrally filtered green light. The contrast enhancement enables the perception of approximately 10%-30% more vascular structures without the introduction of any contrast agent.

  19. Contrast agents in dynamic contrast-enhanced magnetic resonance imaging

    PubMed Central

    Yan, Yuling; Sun, Xilin; Shen, Baozhong

    2017-01-01

    Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is a noninvasive method to assess angiogenesis, which is widely used in clinical applications including diagnosis, monitoring therapy response and prognosis estimation in cancer patients. Contrast agents play a crucial role in DCE-MRI and should be carefully selected in order to improve accuracy in DCE-MRI examination. Over the past decades, there was much progress in the development of optimal contrast agents in DCE-MRI. In this review, we describe the recent research advances in this field and discuss properties of contrast agents, as well as their advantages and disadvantages. Finally, we discuss the research perspectives for improving this promising imaging method. PMID:28415647

  20. Contrast-Enhanced Ultrasonography in Crohn's Disease Diagnostics.

    PubMed

    Białecki, Marcin; Białecka, Agnieszka; Laskowska, Katarzyna; Liebert, Ariel; Kłopocka, Maria; Serafin, Zbigniew

    2015-06-01

    The chronic nature of Crohn's disease (CD) implicates necessity of multiple control assessments throughout patient's life. It is accepted that in patients with CD requiring disease monitoring, magnetic resonance enterography (MRE) and computed tomography enterography (CTE) are--apart from endoscopy--imaging studies of first choice. In practice, diagnostic imaging of patients with CD is troublesome, since MRE is an expensive and complicated study, and CTE exposes patients to high doses of ionizing radiation. Therefore, there is a need for new, both non-invasive and effective, methods of imaging in CD. Contrast-Enhanced Ultrasonography (CEUS) is a relatively new method using gas-filled microbubbles serving as contrast agent. It allows for detailed assessment of blood perfusion within intestine wall and peri-intestinal tissues, which enables detection and monitoring of inflammation and its qualitative assessment. The purpose of this paper is to describe CEUS examination technique and its clinical applications in patients with Crohn's disease.

  1. Microvascular contrast enhancement in optical coherence tomography using microbubbles

    NASA Astrophysics Data System (ADS)

    Assadi, Homa; Demidov, Valentin; Karshafian, Raffi; Douplik, Alexandre; Vitkin, I. Alex

    2016-07-01

    Gas microbubbles (MBs) are investigated as intravascular optical coherence tomography (OCT) contrast agents. Agar + intralipid scattering tissue phantoms with two embedded microtubes were fabricated to model vascular blood flow. One was filled with human blood, and the other with a mixture of human blood + MB. Swept-source structural and speckle variance (sv) OCT images, as well as speckle decorrelation times, were evaluated under both no-flow and varying flow conditions. Faster decorrelation times and higher structural and svOCT image contrasts were detected in the presence of MB in all experiments. The effects were largest in the svOCT imaging mode, and uniformly diminished with increasing flow velocity. These findings suggest the feasibility of utilizing MB for tissue hemodynamic investigations and for microvasculature contrast enhancement in OCT angiography.

  2. When to Order a Contrast-Enhanced CT.

    PubMed

    Rawson, James V; Pelletier, Allen L

    2013-09-01

    Family physicians often must determine the most appropriate diagnostic tests to order for their patients. It is essential to know the types of contrast agents, their risks, contraindications, and common clinical scenarios in which contrast-enhanced computed tomography is appropriate. Many types of contrast agents can be used in computed tomography: oral, intravenous, rectal, and intrathecal. The choice of contrast agent depends on route of administration, desired tissue differentiation, and suspected diagnosis. Possible contraindications for using intravenous contrast agents during computed tomography include a history of reactions to contrast agents, pregnancy, radioactive iodine treatment for thyroid disease, metformin use, and chronic or acutely worsening renal disease. The American College of Radiology Appropriateness Criteria is a useful online resource. Clear communication between the physician and radiologist is essential for obtaining the most appropriate study at the lowest cost and risk to the patient.

  3. Design of a clinical vein contrast enhancing projector

    NASA Astrophysics Data System (ADS)

    Zeman, Herbert D.; Lovhoiden, Gunnar; Deshmukh, Harshal

    2001-06-01

    A clinical study has been initiated to compare an experimental IR device, the Vein Contrast Enhancer (VCE), with standard techniques for finding veins for venipuncture. The aims of this proposal are (1) to evaluate the performance of the VCE in a clinical setting, specifically by comparing its sensitivity of detection with existing vein-finding techniques used by experienced nurses or phlebotomists, (2) to study its usefulness in subjects who are obese, who have difficult venous access or thrombosed veins, or whose veins are not visible or difficult to palpate, and (3) to show that it performs as well on subjects with darkly pigmented skin as on subjects with lightly pigmented skin. The VCE will first be studied in adult subjects, and then in pediatric subjects.

  4. Contrast enhanced ultrasound (CEUS) in blunt abdominal trauma.

    PubMed

    Cagini, Lucio; Gravante, Sabrina; Malaspina, Corrado Maria; Cesarano, Elviro; Giganti, Melchiorre; Rebonato, Alberto; Fonio, Paolo; Scialpi, Michele

    2013-07-15

    In the assessment of polytrauma patient, an accurate diagnostic study protocol with high sensitivity and specificity is necessary. Computed Tomography (CT) is the standard reference in the emergency for evaluating the patients with abdominal trauma. Ultrasonography (US) has a high sensitivity in detecting free fluid in the peritoneum, but it does not show as much sensitivity for traumatic parenchymal lesions. The use of Contrast-Enhanced Ultrasound (CEUS) improves the accuracy of the method in the diagnosis and assessment of the extent of parenchymal lesions. Although the CEUS is not feasible as a method of first level in the diagnosis and management of the polytrauma patient, it can be used in the follow-up of traumatic injuries of abdominal parenchymal organs (liver, spleen and kidneys), especially in young people or children.

  5. Contrast enhanced ultrasound (CEUS) in blunt abdominal trauma

    PubMed Central

    2013-01-01

    In the assessment of polytrauma patient, an accurate diagnostic study protocol with high sensitivity and specificity is necessary. Computed Tomography (CT) is the standard reference in the emergency for evaluating the patients with abdominal trauma. Ultrasonography (US) has a high sensitivity in detecting free fluid in the peritoneum, but it does not show as much sensitivity for traumatic parenchymal lesions. The use of Contrast-Enhanced Ultrasound (CEUS) improves the accuracy of the method in the diagnosis and assessment of the extent of parenchymal lesions. Although the CEUS is not feasible as a method of first level in the diagnosis and management of the polytrauma patient, it can be used in the follow-up of traumatic injuries of abdominal parenchymal organs (liver, spleen and kidneys), especially in young people or children. PMID:23902930

  6. Denoising in Contrast-Enhanced X-ray Images

    NASA Astrophysics Data System (ADS)

    Jeon, Gwanggil

    2016-12-01

    In this paper, we propose a denoising and contrast-enhancement method for medical images. The main purpose of medical image improvement is to transform lower contrast data into higher contrast, and to reduce high noise levels. To meet this goal, we propose a noise-level estimation method, whereby the noise level is estimated by computing the standard deviation and variance in a local block. The obtained noise level is then used as an input parameter for the block-matching and 3D filtering (BM3D) algorithm, and the denoising process is then performed. Noise-level estimation step is important because the BM3D algorithm does not perform well without correct noise-level information. Simulation results confirm that the proposed method outperforms other benchmarks with respect to both their objective and visual performances.

  7. Role of contrast-enhanced endoscopic ultrasound in lymph nodes

    PubMed Central

    Hocke, Michael; Ignee, Andre; Dietrich, Christoph

    2017-01-01

    Diagnosing unclear lymph node (LN) enlargements in the mediastinum and abdomen is the most important indication of endoscopic ultrasound (EUS)-fine needle aspiration (FNA) after the diagnosis and treatment of pancreatic diseases. Investigating LNs in these areas can happen in different clinical settings. Mostly, it is the first modality in general LN diseases without any peripheral LN enlargements. On the other hand, it can be the question of LN involvement in a known or suspected primary tumor. Due to EUS-FNA cytology, those questions can be answered highly, accurately. However, a primary discrimination of LNs might be helpful to increase the diagnostic value of the FNA cytology, especially in cases with multiple LN enlargements and hard to reach enlarged LNs for example by vessel interposition. Because of the unreliability of B-mode criteria, further diagnostic improvements such as elastography and contrast-enhanced EUS are investigated to increase the accuracy of the initial diagnosis. PMID:28218194

  8. Image contrast enhancement based on a local standard deviation model

    SciTech Connect

    Chang, Dah-Chung; Wu, Wen-Rong

    1996-12-31

    The adaptive contrast enhancement (ACE) algorithm is a widely used image enhancement method, which needs a contrast gain to adjust high frequency components of an image. In the literature, the gain is usually inversely proportional to the local standard deviation (LSD) or is a constant. But these cause two problems in practical applications, i.e., noise overenhancement and ringing artifact. In this paper a new gain is developed based on Hunt`s Gaussian image model to prevent the two defects. The new gain is a nonlinear function of LSD and has the desired characteristic emphasizing the LSD regions in which details are concentrated. We have applied the new ACE algorithm to chest x-ray images and the simulations show the effectiveness of the proposed algorithm.

  9. Contrast enhancement in natural scenes using multiband polarization methods

    NASA Astrophysics Data System (ADS)

    Duggin, Michael J.; Kinn, Gerald J.; Bohling, Edward H.

    1997-10-01

    Relatively little work has been performed to investigate the potential of polarization techniques to provide contrast enhancement in natural scenes. Largely, this is because film is less accurate radiometrically than digital CCD FPA sensing devices. Such enhancement is additional to that provided by between-band differences for multiband data. Recently, Kodak has developed several digital imaging cameras which were intended for professional photographers. The variant we used obtained images in the green, red and near infrared, simulating CIR film. However, the application of linear drivers to rad the data from the camera into the computer has resulted in a device which can be used as a multiband imaging polarimeter. Here we examine the potential of digital image acquisition as a potential quantitative method to obtain new information additional to that obtained by multiband or even hyperspectral imaging methods. We present an example of an active on-going research program.

  10. Unilateral versus bilateral middle cerebral artery detection of right-to-left shunt by power M-mode transcranial doppler.

    PubMed

    Jesurum, Jill T; Fuller, Cindy J; Moehring, Mark A; Renz, Joshua; Harley, Meryl; Spencer, Merrill P

    2009-07-01

    Comparison was performed between unilateral and bilateral power M-mode transcranial Doppler to detect right-to-left circulatory shunt (RLS). Recorded Doppler data from 87 patients with confirmed RLS referred for transcatheter closure of patent foramen ovale were reanalyzed for embolic tracks (ET) counted from left and right temporal bone windows during bubble study. Unilateral counts were obtained by multiplying each side by 2; bilateral counts were obtained by summing left and right ET. Both unilateral and bilateral ET were converted to a 6-point logarithmic grade. Sex and age group subanalyses were performed. At rest, significantly more ET were detected with bilateral versus unilateral detection (P= .01), but not following Valsalva (P= .13). Unilateral and bilateral detection were equally able to detect large RLS (grades IV or V) following Valsalva (P= 1.00). For the group aged > or =55 years, the right-hand side yielded greater ET than the left-hand side (mean difference 9%+/- 37; 95% confidence interval -3 to 21%) at rest (P= .01), but not following Valsalva (mean difference 1%+/- 25; 95% confidence interval -7 to 9%, P= .10). Unilateral detection of ET by power M-mode transcranial Doppler is equivalent to bilateral detection to assess RLS.

  11. Contrast-enhanced ultrasonography to diagnose complicated acute cholecystitis.

    PubMed

    Sagrini, Elisabetta; Pecorelli, Anna; Pettinari, Irene; Cucchetti, Alessandro; Stefanini, Federico; Bolondi, Luigi; Piscaglia, Fabio

    2016-02-01

    Gangrenous cholecystitis and perforation are severe complications of acute cholecystitis, which have a challenging preoperative diagnosis. Early identification allows better surgical management. Contrast-enhanced computed tomography (ceCT) is the current diagnostic gold standard. Contrast-enhanced ultrasonography (CEUS) is a promising tool for the diagnosis of gallbladder perforation, but data from the literature concerning efficacy are sparse. The aim of the study was to evaluate CEUS findings in pathologically proven complicated cholecystitis (gangrenous, perforated gallbladder, pericholecystic abscess). A total of 8 patients submitted to preoperative CEUS, and with subsequent proven acute complicated cholecystitis at surgical inspection and pathological analysis, were retrospectively identified. The final diagnosis was gangrenous/phlegmonous cholecystitis (n. 2), phlegmonous/ulcerative changes plus pericholecystic abscess (n. 2), perforated plus pericholecystic abscess (n. 3), or perforated plus pericholecystic biliary collection (n. 1). Conventional US findings revealed irregularly thickened gallbladder walls in all 8 patients, with vaguely defined walls in 7 patients, four of whom also had striated wall thickening. CEUS revealed irregular enhancing gallbladder walls in all patients. A distinct wall defect was seen in six patients, confirmed as gangrenous/phlegmonous cholecystitis at pathology in all six, and in four as perforation at macroscopic surgical inspection. CEUS is a non-invasive easily repeatable technique that can be performed at the bedside, and is able to accurately diagnose complicated/perforated cholecystitis. Despite the limited sample size in the present case series, CEUS appears as a promising tool for the management of patients with the clinical possibility of having an acute complicated cholecystitis.

  12. Contrast-enhanced microwave detection and treatment of breast cancer

    NASA Astrophysics Data System (ADS)

    Gao, Fuqiang

    Contrast agents and heating agents have been proposed for microwave breast tumor imaging and treatment, respectively. The dielectric properties of the tumor are altered with contrast agents or heating agents that locally accumulate in the tumor. The resulting change in dielectric properties of the tumor has the potential to enhance the sensitivity of microwave imaging of breast tumors and increase the efficiency and selectivity of microwave thermal therapy of breast tumors. This dissertation addresses several key challenges in contrast-enhanced microwave imaging and treatment of breast tumors. Carbon nanotubes (CNTs) have been shown to enhance both the relative permittivity and effective conductivity of the host medium, and are promising as theranostic (integrated therapeutic and diagnostic) agents. Thus, our properties characterization work focuses on CNT dispersions. We performed in vitro microwave dielectric properties and heating response characterization of dispersions of CNTs treated by different functionalization methods and identified a CNT formulation that is very promising as a microwave theranostic agent. Stable dispersions of CNTs with concentrations up to 20 mg/ml are obtained with this formulation, and the enhanced microwave properties of these dispersions are extraordinary compared to the control. We also conducted in vivo dielectric properties characterization of mouse tumors with intra-tumoral injections of CNT dispersions and confirmed that the presence of CNTs increases the dielectric properties of the tumor. In parallel, we developed a contrast-enhanced microwave breast tumor imaging algorithm using sparse reconstruction methods. We demonstrated that this algorithm accurately localizes small tumors in 3D numerical breast phantoms. We also demonstrated the experimental feasibility of this method using physical breast phantoms. Lastly, we studied the sensitivity of the distorted Born iterative method (DBIM) to initial guesses and developed a

  13. Contrast-enhanced ultrasound (CEUS) in blunt abdominal trauma

    PubMed Central

    Piccolo, Claudia Lucia; Galluzzo, Michele; Ianniello, Stefania; Sessa, Barbara; Trinci, Margherita

    2016-01-01

    Baseline ultrasound is essential in the early assessment of patients with a huge haemoperitoneum undergoing an immediate abdominal surgery; nevertheless, even with a highly experienced operator, it is not sufficient to exclude parenchymal injuries. More recently, a new ultrasound technique using second generation contrast agents, named contrast-enhanced ultrasound (CEUS) has been developed. This technique allows all the vascular phase to be performed in real time, increasing ultrasound capability to detect parenchymal injuries, enhancing some qualitative findings, such as lesion extension, margins and its relationship with capsule and vessels. CEUS has been demonstrated to be almost as sensitive as contrast-enhanced CT in the detection of traumatic injuries in patients with low-energy isolated abdominal trauma, with levels of sensitivity and specificity up to 95%. Several studies demonstrated its ability to detect lesions occurring in the liver, spleen, pancreas and kidneys and also to recognize active bleeding as hyperechoic bands appearing as round or oval spots of variable size. Its role seems to be really relevant in paediatric patients, thus avoiding a routine exposure to ionizing radiation. Nevertheless, CEUS is strongly operator dependent, and it has some limitations, such as the cost of contrast media, lack of panoramicity, the difficulty to explore some deep regions and the poor ability to detect injuries to the urinary tract. On the other hand, it is timesaving, and it has several advantages, such as its portability, the safety of contrast agent, the lack to ionizing radiation exposure and therefore its repeatability, which allows follow-up of those traumas managed conservatively, especially in cases of fertile females and paediatric patients. PMID:26607647

  14. Initial Clinical Experience with Contrast-Enhanced Digital Breast Tomosynthesis

    PubMed Central

    Chen, Sara C.; Carton, Ann-Katherine; Albert, Michael; Conant, Emily F.; Schnall, Mitchell D.; Maidment, Andrew D. A.

    2007-01-01

    RATIONALE and OBJECTIVES Contrast-enhanced digital mammography and digital breast tomosynthesis are 2 imaging techniques that attempt to increase malignant breast lesion conspicuity. The combination of these into a single technique, contrast-enhanced digital breast tomosynthesis (CE-DBT), could potentially integrate the strengths of both. The objectives of this study were to assess the clinical feasibility of CE-DBT as an adjunct to digital mammography, and to correlate lesion enhancement characteristics and morphology obtained with CE-DBT to digital mammography, ultrasound, and magnetic resonance (MR). MATERIALS and METHODS CE-DBT (GE Senographe 2000D, Milwaukee, WI) was performed as a pilot study in an ongoing NCI-funded grant (P01 CA85484) studying multimodality breast imaging. 13 patients with ACR BI-RADS category 4 or 5 breast lesions underwent imaging with digital mammography, ultrasound, MR, and CE-DBT. CE-DBT was performed at 45-49 kVp with a rhodium target and a 0.27 mm copper (Alfa Aesar, Ward Hill, MA) filter. Pre- and post-injection DBT image sets were acquired in the MLO projection with slight compression. Each image set consists of 9 images acquired over a 50° arc and was obtained with a mean glandular x-ray dose comparable to two conventional mammographic views. Between the pre- and post-contrast DBT image sets, a single bolus of iodinated contrast agent (1 ml/kg at 2 ml/s; Omnipaque-300, Amersham Health Inc., Princeton, NJ) was administered. Images were reconstructed using filtered-backprojection in 1 mm increments, and transmitted to a clinical PACS workstation. RESULTS Initial experience suggests that CE-DBT provides morphologic and vascular characteristics of breast lesions qualitatively concordant with that of digital mammography and MR. CONCLUSION As an adjunct to digital mammography, CE-DBT may be a potential alternative tool for breast lesion morphologic and vascular characterization. PMID:17236995

  15. Contrast-enhanced ultrasound in differentiating malignant from benign portal vein thrombosis in hepatocellular carcinoma

    PubMed Central

    Tarantino, Luciano; Ambrosino, Pasquale; Di Minno, Matteo Nicola Dario

    2015-01-01

    Portal vein thrombosis (PVT) may occur in liver cirrhosis patients. Malignant PVT is a common complication in cirrhotic patients with concomitant hepatocellular carcinoma (HCC) and, in some cases, it may be even the initial sign of an undetected HCC. Detection of malignant PVT in a patient with liver cirrhosis heavily affects the therapeutic strategy. Gray-scale ultrasound (US) is widely unreliable for differentiating benign and malignant thrombi. Although effective for this differential diagnosis, fine-needle biopsy remains an invasive technique. Sensitivity of color-doppler US in detection of malignant thrombi is highly dependent on the size of the thrombus. Contrast-enhanced computed tomography (CT) and contrast-enhanced magnetic resonance (MRI) can be useful to assess the nature of portal thrombus, while limited data are currently available about the role of positron emission tomography (PET) and PET-CT. In contrast with CT, MRI, PET, and PET-CT, contrast-enhanced ultrasound (CEUS) is a fast, effective, well tolerated and cheap technique, that can be performed even in the same session in which the thrombus has been detected. CEUS can be performed bedside and can be available also in transplanted patients. Moreover, CT and MRI only yield a snapshot analysis during contrast diffusion, while CEUS allows for a continuous real-time imaging of the microcirculation that lasts several minutes, so that the whole arterial phase and the late parenchymal phase of the contrast diffusion can be analyzed continuously by real-time US scanning. Continuous real-time monitoring of contrast diffusion entails an easy detection of thrombus maximum enhancement. Moreover, continuous quantitative analyses of enhancement (wash in - wash out studies) by CEUS during contrast diffusion is nowadays available in most CEUS machines, thus giving a more sophisticated and accurate evaluation of the contrast distribution and an increased confidence in diagnosis in difficult cases. In conclusion

  16. Image analysis of placental issues using three-dimensional ultrasound and color power Doppler based on Support Vector Machine

    NASA Astrophysics Data System (ADS)

    Wang, Qi; Xu, Diyun; Liu, Jianguo

    2009-10-01

    With the development of medical science, three-dimensional ultrasound and color power Doppler tomography shooting placenta is widely used. To determine whether the fetus's development is abnormal or not is mainly through the analysis of the capillary's distribution of the obtained images which are shot by the Doppler scanner. In this classification process, we will adopt Support Vector Machine classifier. SVM achieves substantial improvements over the statistical learning methods and behaves robustly over a variety of different learning tasks. Furthermore, it is fully automatic, eliminating the need for manual parameter tuning and can solve the small sample problem wonderfully well. So SVM classifier is valid and reliable in the identification of placentas and is more accurate with the lower error rate.

  17. Ray tracing model for the estimation of power spectral properties in laser Doppler velocimetry of retinal vessels and its potential application to retinal vessel oximetry

    NASA Astrophysics Data System (ADS)

    Petrig, Benno L.; Follonier, Lysianne

    2005-12-01

    A new model based on ray tracing was developed to estimate power spectral properties in laser Doppler velocimetry of retinal vessels and to predict the effects of laser beam size and eccentricity as well as absorption of laser light by oxygenated and reduced hemoglobin. We describe the model and show that it correctly converges to the traditional rectangular shape of the Doppler shift power spectrum, given the same assumptions, and that reduced beam size and eccentric alignment cause marked alterations in this shape. The changes in the detected total power of the Doppler-shifted light due to light scattering and absorption by blood can also be quantified with this model and may be used to determine the oxygen saturation in retinal arteries and veins. The potential of this approach is that it uses direct measurements of Doppler signals originating from moving red blood cells. This may open new avenues for retinal vessel oximetry.

  18. Dynamic Contrast-Enhanced MRI of Cervical Cancers: Temporal Percentile Screening of Contrast Enhancement Identifies Parameters for Prediction of Chemoradioresistance

    SciTech Connect

    Andersen, Erlend K.F.; Hole, Knut Hakon; Lund, Kjersti V.; Sundfor, Kolbein; Kristensen, Gunnar B.; Lyng, Heidi; Malinen, Eirik

    2012-03-01

    Purpose: To systematically screen the tumor contrast enhancement of locally advanced cervical cancers to assess the prognostic value of two descriptive parameters derived from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Methods and Materials: This study included a prospectively collected cohort of 81 patients who underwent DCE-MRI with gadopentetate dimeglumine before chemoradiotherapy. The following descriptive DCE-MRI parameters were extracted voxel by voxel and presented as histograms for each time point in the dynamic series: normalized relative signal increase (nRSI) and normalized area under the curve (nAUC). The first to 100th percentiles of the histograms were included in a log-rank survival test, resulting in p value and relative risk maps of all percentile-time intervals for each DCE-MRI parameter. The maps were used to evaluate the robustness of the individual percentile-time pairs and to construct prognostic parameters. Clinical endpoints were locoregional control and progression-free survival. The study was approved by the institutional ethics committee. Results: The p value maps of nRSI and nAUC showed a large continuous region of percentile-time pairs that were significantly associated with locoregional control (p < 0.05). These parameters had prognostic impact independent of tumor stage, volume, and lymph node status on multivariate analysis. Only a small percentile-time interval of nRSI was associated with progression-free survival. Conclusions: The percentile-time screening identified DCE-MRI parameters that predict long-term locoregional control after chemoradiotherapy of cervical cancer.

  19. Prospective comparison of use of contrast-enhanced ultrasound and contrast-enhanced computed tomography in the Bosniak classification of complex renal cysts

    PubMed Central

    Ragel, Matthew; Nedumaran, Anbu

    2016-01-01

    Aim To compare contrast-enhanced ultrasound and contrast-enhanced computed tomography in the evaluation of complex renal cysts using the Bosniak classification. Methods Forty-six patients with 51 complex renal cysts were prospectively examined using contrast-enhanced ultrasound and contrast-enhanced computed tomography and images analysed by two observers using the Bosniak classification. Adverse effects and patients’ preference were assessed for both modalities. Results There was complete agreement in Bosniak classification between both modalities and both observers in six cysts (11.8%). There was agreement of Bosniak classification on both modalities in 21 of 51 cysts (41.2%) for observer 1 and in 17 of 51 cysts (33.3%) for observer 2. Contrast-enhanced ultrasound gave a higher Bosniak classification than corresponding contrast-enhanced computed tomography in 31 % of cysts by both observers. Histological correlation was available in three lesions, all of which were malignant and classified as such simultaneously on both modalities by at least one observer, with remaining patients followed up with US or CT for 6–24 months. No adverse or side effects were reported following the use of US contrast, whilst 63.6% of patients suffered minor side effects following the use of CT contrast. 81.8% of the surveyed patients preferred contrast-enhanced ultrasound to contrast-enhanced computed tomography. Conclusion Contrast-enhanced ultrasound is a feasible tool in the evaluation of complex renal cysts in a non-specialist setting. Increased contrast-enhanced ultrasound sensitivity to enhancement compared to contrast-enhanced computed tomography, resulting in upgrading the Bosniak classification on contrast-enhanced ultrasound, has played a role in at best moderate agreement recorded by the observers with limited experience, but this would be overcome as the experience grows. To this end, we propose a standardised proforma for the contrast-enhanced ultrasound report. The

  20. Evaluation of the effect of machine settings on quantitative three-dimensional power Doppler angiography: an in-vitro flow phantom experiment.

    PubMed

    Raine-Fenning, N J; Nordin, N M; Ramnarine, K V; Campbell, B K; Clewes, J S; Perkins, A; Johnson, I R

    2008-09-01

    Three-dimensional (3D) ultrasound is being used increasingly to acquire and subsequently quantify power Doppler data within the clinical setting. One proprietary software package calculates three 3D vascular indices: the vascularization index (VI), the flow index (FI), and the vascularization flow index (VFI). Our aim was to evaluate how different settings affect the Doppler signal in terms of its quantification by these three indices within a 3D dataset. A computer-driven 'flow phantom' was used to continuously pump a nylon particle-based blood mimic (Orgasol(trade mark)) around a closed system through a C-flex(trade mark) tube embedded in an agar-based tissue mimic. The test tanks were insonated with a modified 3D transvaginal 4-8-MHz ultrasound transducer (V530D) and power Doppler data were acquired over a series of different settings. Each experiment involved the manipulation of just one Doppler setting in order to study it in isolation. As expected, all of the power Doppler settings, when altered, were found to effect significant changes (P < 0.05) in the VI, FI and VFI. The gain and signal power had the greatest effect, producing no Doppler signals at the lowest settings and the highest recordable indices at the maximum settings. The pulse repetition frequency (PRF) was the next most influential setting but a Doppler signal was seen and measurable at all of the different settings. The other Doppler settings had a much less profound effect on the vascular indices, with subtle but significantly different measures across the full range of settings. The speed of data acquisition was also found to affect the vascular indices, all of which were reduced when the fast mode was used although the only significant effect was on the VFI. The VI, FI and VFI are all affected significantly by variations in power Doppler settings and by the speed of acquisition. The gain and signal power have the greatest effect on the power Doppler signal, followed closely by the PRF. The

  1. Hepatic Fibrosis: Evaluation with Semiquantitative Contrast-enhanced CT

    PubMed Central

    Varenika, Vanja; Fu, Yanjun; Maher, Jacquelyn J.; Gao, Dongwei; Kakar, Sanjay; Cabarrus, Miguel C.

    2013-01-01

    Purpose: To evaluate the feasibility of using contrast material–enhanced computed tomographic (CT) measurements of hepatic fractional extracellular space (fECS) and macromolecular contrast material (MMCM) uptake to measure severity of liver fibrosis. Materials and Methods: All procedures were approved by and executed in accordance with University of California, San Francisco, institutional animal care and use committee regulations. Twenty-one rats that received intragastric CCl4 for 0–12 weeks were imaged with respiratory-gated micro-CT by using both a conventional contrast material and a novel iodinated MMCM. Histopathologic hepatic fibrosis was graded qualitatively by using the Ishak fibrosis score and quantitatively by using morphometry of the fibrosis area. Hepatic fECS and MMCM uptake were calculated for each examination and correlated with histopathologic findings by using uni- and multivariate linear regressions. Results: Ishak fibrosis scores ranged from a baseline of 0 in untreated animals to a maximum of 5. Histopathologic liver fibrosis area increased from 0.46% to 3.5% over the same interval. Strong correlations were seen between conventional contrast-enhanced CT measurements of fECS and both the Ishak fibrosis scores (R2 = 0.751, P < .001) and the fibrosis area (R2 = 0.801, P < .001). Strong negative correlations were observed between uptake of MMCM in the liver and Ishak fibrosis scores (R2 = 0.827, P < .001), as well as between uptake of MMCM in the liver and fibrosis area (R2 = 0.643, P = .001). Multivariate linear regression analysis showed a trend toward independence for fECS and MMCM uptake in the prediction of Ishak fibrosis scores, with an R2 value of 0.86 (P = .081 and P = .033, respectively). Conclusion: Contrast-enhanced CT measurements of fECS and MMCM uptake are individually capable of being used to estimate the degree of early hepatic fibrosis in a rat model. © RSNA, 2012 Supplemental material: http

  2. Contrast-enhanced fluorodeoxyglucose positron emission tomography/contrast-enhanced computed tomography in mediastinal T-cell lymphoma with superior vena cava syndrome.

    PubMed

    Santhosh, Sampath; Gorla, Arun Kumar Reddy; Bhattacharya, Anish; Varma, Subhash Chander; Mittal, Bhagwant Rai

    2016-01-01

    Positron emission tomography-computed tomography (PET/CT) is a routine investigation for the staging of lymphomas. Contrast-enhanced computed tomography is mandatory whenever parenchymal lesions, especially in the liver and spleen are suspected. We report a rare case of primary mediastinal T-cell lymphoma evaluated with contrast-enhanced PET/CT that showed features of superior vena cava syndrome.

  3. Severe Portal Hypertension in Cirrhosis: Evaluation of Perfusion Parameters with Contrast-Enhanced Ultrasonography

    PubMed Central

    Sohn, Joo Hyun; Kim, Yongsoo; Kim, Jinoo

    2015-01-01

    Objective To investigate the role of contrast-enhanced ultrasonography (CEUS) and Doppler ultrasonography (DUS) in the diagnosis of severe portal hypertension (PH) in patients with liver cirrhosis (LC). Methods Patients with PH scheduled to receive hepatic venous pressure gradient (HVPG) measurement were recruited for this study. Hepatic DUS and CEUS were performed successively. Several Doppler and CEUS parameters were explored for correlation with HVPG values and their association with severe PH (≥ 12 mmHg of HVPG). Comparison of the parameters between the severe and non-severe PH groups and their correlation with HVPG values was evaluated. A receiver operating characteristic (ROC) curve analysis was also performed to investigate the performance in order to diagnose severe PH. Results Fifty-three consecutive patients were enrolled in this study. Among them, 43 patients did not have significant ascites. Compared with the non-severe PH group, portal venous velocity and intrahepatic transit time (ITT) were significantly reduced in the severe PH group (all p<0.05). Difference between inspiratory and expiratory hepatic venous damping indices (ΔHVDI), hepatic venous arrival time (HVAT) and ITT moderately correlated with HVPG (r = -0.358, -0.338, and -0.613, respectively). Areas under the curves for severe PH were 0.94 of ITT and 0.72 of HVAT, respectively (all p<0.05). ITT under 6 seconds indicated severe PH with a sensitivity of 92% and a specificity of 89%. Conclusions Hepatic CEUS may be more useful in estimating the HVPG value and determining the presence of severe PH compared to DUS, and ITT was the most accurate parameter to diagnose severe PH. PMID:25798930

  4. Nanoparticles and nanostructured carriers for drug delivery and contrast enhancement

    NASA Astrophysics Data System (ADS)

    Godage, Olga S.; Bucharskaya, Alla B.; Navolokin, Nikita A.; German, Sergey V.; Zuev, Viktor V.; Terentyuk, Georgy S.; Maslyakova, Galina N.; Gorin, Dmitry A.

    2016-04-01

    Currently, nanotechnologies are widely used in science and industry. It is known that the application of drug delivery nanostructured carriers for biomedicine is one of the promising areas of nanotechnology. Nanostructured carriers can be used in the diagnosis process for detecting a neoplastic tumor cells in peripheral blood, for contrast enhancement on magnetic resonance imaging (MRI), as well as for targeted drug delivery to tumor tissues. Agents for the targeted delivery (nanoparticles, liposomes, microcapsules, and etc) can affect the healthy tissues and organs, cause side effects and have a toxic effect. Therefore, it necessary to study the morphological changes that occur not only in the "target", such as a tumor, but also the internal organs, taking place under the influence of both the agents for targeted drug delivery and physical impact induced remote controlled drug release. Thus , the aim of our work is selection of the most promising agents for targeted drug delivery to tumor and contrast agents for in vivo visualization of tumor tissue boundaries , as well as their impact on the organs and tissues as results of nanostructured object biodistribution.

  5. Motion correction of dynamic contrast enhanced MRI of the liver

    NASA Astrophysics Data System (ADS)

    Jansen, Mariëlle J. A.; Veldhuis, Wouter B.; van Leeuwen, Maarten S.; Pluim, Josien P. W.

    2017-02-01

    Motion correction of dynamic contrast enhanced magnetic resonance images (DCE-MRI) is a challenging task, due to changes in image appearance. In this study a groupwise registration, using a principle component analysis (PCA) based metric, is evaluated for clinical DCE MRI of the liver. The groupwise registration transforms the images to a common space, rather than to a reference volume as conventional pairwise methods do, and computes the similarity metric on all volumes simultaneously. This groupwise registration method is compared to a pairwise approach using a mutual information metric. Clinical DCE MRI of the abdomen of eight patients were included. Per patient one lesion in the liver was manually segmented in all temporal images (N=16). The registered images were compared for accuracy, spatial and temporal smoothness after transformation, and lesion volume change. Compared to a pairwise method or no registration, groupwise registration provided better alignment. In our recently started clinical study groupwise registered clinical DCE MRI of the abdomen of nine patients were scored by three radiologists. Groupwise registration increased the assessed quality of alignment. The gain in reading time for the radiologist was estimated to vary from no difference to almost a minute. A slight increase in reader confidence was also observed. Registration had no added value for images with little motion. In conclusion, the groupwise registration of DCE MR images results in better alignment than achieved by pairwise registration, which is beneficial for clinical assessment.

  6. Contrast-enhanced ultrasound of histologically proven hepatic epithelioid hemangioendothelioma

    PubMed Central

    Dong, Yi; Wang, Wen-Ping; Cantisani, Vito; D’Onofrio, Mirko; Ignee, Andre; Mulazzani, Lorenzo; Saftoiu, Adrian; Sparchez, Zeno; Sporea, Ioan; Dietrich, Christoph F

    2016-01-01

    AIM: To analyze contrast-enhanced ultrasound (CEUS) features of histologically proven hepatic epithelioid hemangioendothelioma (HEHE) in comparison to other multilocular benign focal liver lesions (FLL). METHODS: Twenty-five patients with histologically proven HEHE and 45 patients with histologically proven multilocular benign FLL were retrospectively reviewed. Four radiologists assessed the CEUS enhancement pattern in consensus. RESULTS: HEHE manifested as a single (n = 3) or multinodular (n = 22) FLL. On CEUS, HEHE showed rim-like (18/25, 72%) or heterogeneous hyperenhancement (7/25, 28%) in the arterial phase and hypoenhancement (25/25, 100%) in the portal venous and late phases (PVLP), a sign of malignancy. Eighteen patients showed central unenhanced areas (18/25, 72%); in seven patients (7/25, 28%), more lesions were detected in the PVLP. In contrast, all patients with hemangioma and focal nodular hyperplasia showed hyperenhancement as the most distinctive feature (P < 0.01). CONCLUSION: CEUS allows for characterization of unequivocal FLL. By analyzing the hypoenhancement in the PVLP, CEUS can determine the malignant nature of HEHE. PMID:27217705

  7. Cumulative phase delay imaging for contrast-enhanced ultrasound tomography

    NASA Astrophysics Data System (ADS)

    Demi, Libertario; van Sloun, Ruud J. G.; Wijkstra, Hessel; Mischi, Massimo

    2015-11-01

    Standard dynamic-contrast enhanced ultrasound (DCE-US) imaging detects and estimates ultrasound-contrast-agent (UCA) concentration based on the amplitude of the nonlinear (harmonic) components generated during ultrasound (US) propagation through UCAs. However, harmonic components generation is not specific to UCAs, as it also occurs for US propagating through tissue. Moreover, nonlinear artifacts affect standard DCE-US imaging, causing contrast to tissue ratio reduction, and resulting in possible misclassification of tissue and misinterpretation of UCA concentration. Furthermore, no contrast-specific modality exists for DCE-US tomography; in particular speed-of-sound changes due to UCAs are well within those caused by different tissue types. Recently, a new marker for UCAs has been introduced. A cumulative phase delay (CPD) between the second harmonic and fundamental component is in fact observable for US propagating through UCAs, and is absent in tissue. In this paper, tomographic US images based on CPD are for the first time presented and compared to speed-of-sound US tomography. Results show the applicability of this marker for contrast specific US imaging, with cumulative phase delay imaging (CPDI) showing superior capabilities in detecting and localizing UCA, as compared to speed-of-sound US tomography. Cavities (filled with UCA) which were down to 1 mm in diameter were clearly detectable. Moreover, CPDI is free of the above mentioned nonlinear artifacts. These results open important possibilities to DCE-US tomography, with potential applications to breast imaging for cancer localization.

  8. Image fusion for dynamic contrast enhanced magnetic resonance imaging

    PubMed Central

    Twellmann, Thorsten; Saalbach, Axel; Gerstung, Olaf; Leach, Martin O; Nattkemper, Tim W

    2004-01-01

    Background Multivariate imaging techniques such as dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) have been shown to provide valuable information for medical diagnosis. Even though these techniques provide new information, integrating and evaluating the much wider range of information is a challenging task for the human observer. This task may be assisted with the use of image fusion algorithms. Methods In this paper, image fusion based on Kernel Principal Component Analysis (KPCA) is proposed for the first time. It is demonstrated that a priori knowledge about the data domain can be easily incorporated into the parametrisation of the KPCA, leading to task-oriented visualisations of the multivariate data. The results of the fusion process are compared with those of the well-known and established standard linear Principal Component Analysis (PCA) by means of temporal sequences of 3D MRI volumes from six patients who took part in a breast cancer screening study. Results The PCA and KPCA algorithms are able to integrate information from a sequence of MRI volumes into informative gray value or colour images. By incorporating a priori knowledge, the fusion process can be automated and optimised in order to visualise suspicious lesions with high contrast to normal tissue. Conclusion Our machine learning based image fusion approach maps the full signal space of a temporal DCE-MRI sequence to a single meaningful visualisation with good tissue/lesion contrast and thus supports the radiologist during manual image evaluation. PMID:15494072

  9. Contrast-enhanced ultrasound: clinical applications in patients with atherosclerosis.

    PubMed

    Schinkel, Arend F L; Kaspar, Mathias; Staub, Daniel

    2016-01-01

    Contrast-enhanced ultrasound (CEUS) is increasingly being used to evaluate patients with known or suspected atherosclerosis. The administration of a microbubble contrast agent in conjunction with ultrasound results in an improved image quality and provides information that cannot be assessed with standard B-mode ultrasound. CEUS is a high-resolution, noninvasive imaging modality, which is safe and may benefit patients with coronary, carotid, or aortic atherosclerosis. CEUS allows a reliable assessment of endocardial borders, left ventricular function, intracardiac thrombus and myocardial perfusion. CEUS results in an improved detection of carotid atherosclerosis, and allows assessment of high-risk plaque characteristics including intraplaque vascularization, and ulceration. CEUS provides real-time bedside information in patients with a suspected or known abdominal aortic aneurysm or aortic dissection. The absence of ionizing radiation and safety of the contrast agent allow repetitive imaging which is particularly useful in the follow-up of patients after endovascular aneurysm repair. New developments in CEUS-based molecular imaging will improve the understanding of the pathophysiology of atherosclerosis and may in the future allow to image and directly treat cardiovascular diseases (theragnostic CEUS). Familiarity with the strengths and limitations of CEUS may have a major impact on the management of patients with atherosclerosis.

  10. Cerebellar dermoid cyst with contrast enhancement mural nodule: case report.

    PubMed

    Morina, Arsim; Kelmendi, Fatos; Morina, Qamile; Morina, Dukagjin

    2014-12-01

    Typical dermoid cysts are well-circumscribed fat-density masses with no associated contrast enhancement; rarely, they may appear hyperattenuating on CT scan. CT hyperattenuating dermoid cyst (CHADC) is very uncommon, with only nine case reports in the literature update, which occurs exclusively in the posterior fossa. CHADC with mural nodule is extremely rare and, to the best of our knowledge, only two cases have been documented previously in the literature. A 49-year-old farmer had a 2-month history of occipital headaches, which were not suggestive of raised intracranial pressure. During the last month, he experienced loss of balance, frequent falls, anorexia and loss of weight. Magnetic resonance imaging (MRI) showed a huge mass from the tentorium to the foramen occipitale magnum with obliteration of the fourth ventricle; the lesion was well circumscribed. We completely removed the tumor and postoperative MRI showed no residual tumor. Epidermoid tumors with enhancing mural nodule on MRI and with hyperattenuating lesion on CT are extremely rare. Dermoid cysts are never associated with edema and extremely rarely cause obstructive hydrocephalus. MRI investigations are mandatory to diagnose these cases. The best curative treatment is total removal of the lesion.

  11. Dynamic Contrast-Enhanced CT in Patients with Pancreatic Cancer

    PubMed Central

    Eriksen, Rie Ø.; Strauch, Louise S.; Sandgaard, Michael; Kristensen, Thomas S.; Nielsen, Michael B.; Lauridsen, Carsten A.

    2016-01-01

    The aim of this systematic review is to provide an overview of the use of Dynamic Contrast-enhanced Computed Tomography (DCE-CT) in patients with pancreatic cancer. This study was composed according to the PRISMA guidelines 2009. The literature search was conducted in PubMed, Cochrane Library, EMBASE, and Web of Science databases to identify all relevant publications. The QUADAS-2 tool was implemented to assess the risk of bias and applicability concerns of each included study. The initial literature search yielded 483 publications. Thirteen articles were included. Articles were categorized into three groups: nine articles concerning primary diagnosis or staging, one article about tumor response to treatment, and three articles regarding scan techniques. In exocrine pancreatic tumors, measurements of blood flow in eight studies and blood volume in seven studies were significantly lower in tumor tissue, compared with measurements in pancreatic tissue outside of tumor, or normal pancreatic tissue in control groups of healthy volunteers. The studies were heterogeneous in the number of patients enrolled and scan protocols. Perfusion parameters measured and analyzed by DCE-CT might be useful in the investigation of characteristic vascular patterns of exocrine pancreatic tumors. Further clinical studies are desired for investigating the potential of DCE-CT in pancreatic tumors. PMID:27608045

  12. Diagnosis of liver cirrhosis with contrast-enhanced ultrasound

    PubMed Central

    Liu, Guang-Jian; Lu, Ming-De

    2010-01-01

    The assessment of the extent of liver fibrosis is very important for the prognosis and clinical management of chronic liver diseases. Although liver biopsy is the gold standard for the assessment of liver fibrosis, new non-invasive diagnostic methods are urgently needed in clinical work due to certain limitations and complications of biopsy. Noninvasive imaging studies play an important role in the diagnosis of focal liver disease and diffuse liver diseases. Among them, ultrasonography is the first choice for study of the liver in clinical work. With the development of ultrasound contrast agents and contrast specific imaging techniques, contrast-enhanced ultrasound (CEUS) shows good performance and great potential in the evaluation of liver fibrosis. Researchers have tried different kinds of contrast agent and imaging method, such as arrival time of contrast agent in the hepatic vein, and quantitative analysis of the enhancement level of liver parenchyma, to evaluate the degree of liver fibrosis during the past 10 years. This review mainly summarizes the clinical studies concerning the assessment of liver fibrosis using CEUS. PMID:21160737

  13. Dynamic Contrast-Enhanced CT in Patients with Pancreatic Cancer.

    PubMed

    Eriksen, Rie Ø; Strauch, Louise S; Sandgaard, Michael; Kristensen, Thomas S; Nielsen, Michael B; Lauridsen, Carsten A

    2016-09-06

    The aim of this systematic review is to provide an overview of the use of Dynamic Contrast-enhanced Computed Tomography (DCE-CT) in patients with pancreatic cancer. This study was composed according to the PRISMA guidelines 2009. The literature search was conducted in PubMed, Cochrane Library, EMBASE, and Web of Science databases to identify all relevant publications. The QUADAS-2 tool was implemented to assess the risk of bias and applicability concerns of each included study. The initial literature search yielded 483 publications. Thirteen articles were included. Articles were categorized into three groups: nine articles concerning primary diagnosis or staging, one article about tumor response to treatment, and three articles regarding scan techniques. In exocrine pancreatic tumors, measurements of blood flow in eight studies and blood volume in seven studies were significantly lower in tumor tissue, compared with measurements in pancreatic tissue outside of tumor, or normal pancreatic tissue in control groups of healthy volunteers. The studies were heterogeneous in the number of patients enrolled and scan protocols. Perfusion parameters measured and analyzed by DCE-CT might be useful in the investigation of characteristic vascular patterns of exocrine pancreatic tumors. Further clinical studies are desired for investigating the potential of DCE-CT in pancreatic tumors.

  14. Simultaneous segmentation and registration of contrast-enhanced breast MRI.

    PubMed

    Xiaohua, Chen; Brady, Michael; Lo, Jonathan Lok-Chuen; Moore, Niall

    2005-01-01

    Breast Contrast-Enhanced MRI (ce-MRI) requires a series of images to be acquired before, and repeatedly after, intravenous injection of a contrast agent. Breast MRI segmentation based on the differential enhancement of image intensities can assist the clinician detect suspicious regions. Image registration between the temporal data sets is necessary to compensate for patient motion, which is quite often substantial. Although segmentation and registration are usually treated as separate problems in medical image analysis, they can naturally benefit a great deal from each other. In this paper, we propose a scheme for simultaneous segmentation and registration of breast ce-MRI. It is developed within a Bayesian framework, based on a maximum a posteriori estimation method. A pharmacokinetic model and Markov Random Field model have been incorporated into the framework in order to improve the performance of our algorithm. Our method has been applied to the segmentation and registration of clinical ce-MR images. The results show the potential of our methodology to extract useful information for breast cancer detection.

  15. Delineation of Tumor Habitats based on Dynamic Contrast Enhanced MRI.

    PubMed

    Chang, Yu-Cherng Channing; Ackerstaff, Ellen; Tschudi, Yohann; Jimenez, Bryan; Foltz, Warren; Fisher, Carl; Lilge, Lothar; Cho, HyungJoon; Carlin, Sean; Gillies, Robert J; Balagurunathan, Yoganand; Yechieli, Raphael L; Subhawong, Ty; Turkbey, Baris; Pollack, Alan; Stoyanova, Radka

    2017-08-29

    Tumor heterogeneity can be elucidated by mapping subregions of the lesion with differential imaging characteristics, called habitats. Dynamic Contrast Enhanced (DCE-)MRI can depict the tumor microenvironments by identifying areas with variable perfusion and vascular permeability, since individual tumor habitats vary in the rate and magnitude of the contrast uptake and washout. Of particular interest is identifying areas of hypoxia, characterized by inadequate perfusion and hyper-permeable vasculature. An automatic procedure for delineation of tumor habitats from DCE-MRI was developed as a two-part process involving: (1) statistical testing in order to determine the number of the underlying habitats; and (2) an unsupervised pattern recognition technique to recover the temporal contrast patterns and locations of the associated habitats. The technique is examined on simulated data and DCE-MRI, obtained from prostate and brain pre-clinical cancer models, as well as clinical data from sarcoma and prostate cancer patients. The procedure successfully identified habitats previously associated with well-perfused, hypoxic and/or necrotic tumor compartments. Given the association of tumor hypoxia with more aggressive tumor phenotypes, the obtained in vivo information could impact management of cancer patients considerably.

  16. Contrast-enhanced MRI of murine myocardial infarction - part II.

    PubMed

    Coolen, Bram F; Paulis, Leonie E M; Geelen, Tessa; Nicolay, Klaas; Strijkers, Gustav J

    2012-08-01

    Mouse models are increasingly used to study the pathophysiology of myocardial infarction in vivo. In this area, MRI has become the gold standard imaging modality, because it combines high spatial and temporal resolution functional imaging with a large variety of methods to generate soft tissue contrast. In addition, (target-specific) MRI contrast agents can be employed to visualize different processes in the cascade of events following myocardial infarction. Here, the MRI sequence has a decisive role in the detection sensitivity of a contrast agent. However, a straightforward translation of clinically available protocols for human cardiac imaging to mice is not feasible, because of the small size of the mouse heart and its extremely high heart rate. This has stimulated intense research in the development of cardiac MRI protocols specifically tuned to the mouse with regard to timing parameters, acquisition strategies, and ECG- and respiratory-triggering methods to find an optimal trade-off between sensitivity, scan time, and image quality. In this review, a detailed analysis is given of the pros and cons of different mouse cardiac MR imaging methodologies and their application in contrast-enhanced MRI of myocardial infarction. Copyright © 2012 John Wiley & Sons, Ltd.

  17. Development of contrast-enhanced rodent imaging using functional CT

    NASA Astrophysics Data System (ADS)

    Liang, Yun; Stantz, Keith M.; Krishnamurthi, Ganapathy; Steinmetz, Rosemary; Hutchins, Gary D.

    2003-05-01

    Micro-computed tomography (microCT) is capable of obtaining high-resolution images of skeletal tissues. However its image contrast among soft tissues remains inadequate for tumor detection. High speed functional computed tomography will be needed to image tumors by employing x-ray contrast medium. The functional microCT development will not only facilitate the image contrast enhancement among different tissues but also provide information of tumor physiology. To demonstrate the feasibility of functional CT in mouse imaging, sequential computed tomography is performed in mice after contrast material administration using a high-speed clinical CT scanner. Although the resolution of the clinical scanner is not sufficient to dissolve the anatomic details of rodents, bulky physiological parameters in major organs such as liver, kidney, pancreas, and ovaries (testicular) can be examined. For data analysis, a two-compartmental model is employed and implemented to characterize the tissue physiological parameters (regional blood flow, capillary permeability, and relative compartment volumes.) The measured contrast dynamics in kidneys are fitted with the compartmental model to derive the kidney tissue physiology. The study result suggests that it is feasible to extract mouse tissue physiology using functional CT imaging technology.

  18. A no-reference perceptual based contrast enhancement metric for ocean scenes in fog.

    PubMed

    Gibson, Kristofor Boyd; Nguyen, Truong Q

    2013-10-01

    In this paper, we develop a perceptually based contrast enhancement metric as a means to solve the problem of autonomously enhancing images degraded by fog that are perceptually pleasing to humans. A learning based approach is considered to develop the contrast enhancement using human observations and low-level contrast enhancement metrics based on the human vision system. In addition, we provide new low-level metrics based on the physics of the scene to improve the performance of existing contrast enhancement metrics. This paper shows that a contrast enhancement metric can be designed to mimic human preference.

  19. Wearable blood flowmeter appcessory with low-power laser Doppler signal processing for daily-life healthcare monitoring.

    PubMed

    Kuwabara, K; Higuchi, Y; Ogasawara, T; Koizumi, H; Haga, T

    2014-01-01

    A new appcessory for monitoring peripheral blood flow in daily life consists of a wearable laser Doppler sensor device and a cooperating smart phone application. Bluetooth Low Energy connects them wirelessly. The sensor device features ultralight weight of 15 g and an intermittent signal processing technique that reduces power consumption to only 7 mW at measurement intervals of 0.1 s. These features enable more than 24-h continuous monitoring of peripheral blood flow in daily life, which can provide valuable vital-sign information for healthcare services.

  20. The diagnostic value of contrast-enhanced ultrasound in differentiating small renal carcinoma and angiomyolipoma.

    PubMed

    Chen, Lin; Wang, Ling; Diao, Xuehong; Qian, Weiqing; Fang, Liang; Pang, Yun; Zhan, Jia; Chen, Yue

    2015-08-01

    The aim of this study was to explore the value of contrast-enhanced ultrasound (CEUS) in differentiating small renal masses. A total of 102 small renal masses (≤ 3 cm) in 99 patients were examined using conventional ultrasound (CUS) and CEUS, and the findings were reviewed and evaluated in comparison to pathology. Significant differences between renal cell carcinomas (RCCs) and angiomyolipomas (AMLs) were noted in terms of the orientation and echogenicity on CUS (p < 0.05 for both), but the location, shape, margins, homogeneity, and blood flow signals of RCCs on color Doppler flow imaging (CDFI) were similar to those of AMLs (p > 0.05 for all). On CEUS, however, the enhancement intensity, washout in the late phase, and perilesional rim-like enhancement differed significantly for RCCs and AMLs (p = 0.000 for all). Significant differences between CEUS and CUS in terms of sensitivity (88.9% vs. 55.6%), the negative predictive value (68.0% vs. 29.5%), the false negative rate (9.9% vs. 44.5%), and accuracy (88.3% vs. 58.9%) were noted (p < 0.05 for all). CEUS, with its unique features, has value in diagnosing small RCCs and AMLs and outperforms CUS in differentiation of small RCCs and AMLs.

  1. The antiangiogenic effects of a vascular endothelial growth factor decoy receptor can be monitored in vivo using contrast-enhanced ultrasound imaging.

    PubMed

    Forsberg, Flemming; Ro, Raymond J; Marshall, Andrew; Liu, Ji-Bin; Chiou, See-Ying; Merton, Daniel A; Machado, Priscilla; Dicker, Adam P; Nazarian, Levon N

    2014-01-01

    The development of antiangiogenic therapies has stimulated interest in noninvasive imaging methods to monitor response. We investigated whether the effects of a vascular endothelial growth factor decoy receptor (VEGF Trap, Regeneron Pharmaceuticals, Tarrytown, NY) could be monitored in vivo using contrast-enhanced ultrasonography (CEUS). Twenty nude mice (in two groups) were implanted with a human melanoma cell line (DB-1). The active group received VEGF Trap (4 × 25 mg/kg over 2 weeks), whereas the control group received an inactive protein. An ultrasound contrast agent was injected followed by power Doppler imaging (PDI) and pulse inversion harmonic imaging (PIHI; regular and intermittent). Specimens were sectioned in the same planes as the images and stained for endothelial cells (CD31), cyclooxygenase-2 (COX-2), VEGF, and hypoxia (Glut1). Measures of tumor vascularity obtained with the different imaging modes were compared to immunohistochemical markers of angiogenesis. Mean tumor volume was smaller in the active group than in the control group (656 ± 225 vs 1,160 ± 605 mm3). Overall, PDI and VEGF correlated (r  =  .34; p =  .037). Vascularity decreased from control to treated mice with intermittent PIHI, as did the expression of CD31 and COX-2 (p ≤ .02), whereas VEGF increased (p  =  .05). CEUS appears to allow in vivo monitoring of the antiangiogenic effects of VEGF Trap in the DB-1 human melanoma xenograft model.

  2. Dynamic contrast-enhanced MRI evaluation of cerebral cavernous malformations.

    PubMed

    Hart, Blaine L; Taheri, Saeid; Rosenberg, Gary A; Morrison, Leslie A

    2013-10-01

    The aim of this study is to quantitatively evaluate the behavior of CNS cavernous malformations (CCMs) using a dynamic contrast-enhanced MRI (DCEMRI) technique sensitive for slow transfer rates of gadolinium. The prospective study was approved by the institutional review board and was HIPPA compliant. Written informed consent was obtained from 14 subjects with familial CCMs (4 men and 10 women, ages 22-76 years, mean 48.1 years). Following routine anatomic MRI of the brain, DCEMRI was performed for six slices, using T1 mapping with partial inversion recovery (TAPIR) to calculate T1 values, following administration of 0.025 mmol/kg gadolinium DTPA. The transfer rate (Ki) was calculated using the Patlak model, and Ki within CCMs was compared to normal-appearing white matter as well as to 17 normal control subjects previously studied. All subjects had typical MRI appearance of CCMs. Thirty-nine CCMs were studied using DCEMRI. Ki was low or normal in 12 lesions and elevated from 1.4 to 12 times higher than background in the remaining 27 lesions. Ki ranged from 2.1E-6 to 9.63E-4 min(-1), mean 3.55E-4. Normal-appearing white matter in the CCM patients had a mean Ki of 1.57E-4, not statistically different from mean WM Ki of 1.47E-4 in controls. TAPIR-based DCEMRI technique permits quantifiable assessment of CCMs in vivo and reveals considerable differences not seen with conventional MRI. Potential applications include correlation with biologic behavior such as lesion growth or hemorrage, and measurement of drug effects.

  3. Cumulative phase delay imaging - A new contrast enhanced ultrasound modality

    SciTech Connect

    Demi, Libertario Sloun, Ruud J. G. van; Mischi, Massimo; Wijkstra, Hessel

    2015-10-28

    Recently, a new acoustic marker for ultrasound contrast agents (UCAs) has been introduced. A cumulative phase delay (CPD) between the second harmonic and fundamental pressure wave field components is in fact observable for ultrasound propagating through UCAs. This phenomenon is absent in the case of tissue nonlinearity and is dependent on insonating pressure and frequency, UCA concentration, and propagation path length through UCAs. In this paper, ultrasound images based on this marker are presented. The ULA-OP research platform, in combination with a LA332 linear array probe (Esaote, Firenze Italy), were used to image a gelatin phantom containing a PVC plate (used as a reflector) and a cylindrical cavity measuring 7 mm in diameter (placed in between the observation point and the PVC plate). The cavity contained a 240 µL/L SonoVueO{sup ®} UCA concentration. Two insonating frequencies (3 MHz and 2.5 MHz) were used to scan the gelatine phantom. A mechanical index MI = 0.07, measured in water at the cavity location with a HGL-0400 hydrophone (Onda, Sunnyvale, CA), was utilized. Processing the ultrasound signals backscattered from the plate, ultrasound images were generated in a tomographic fashion using the filtered back-projection method. As already observed in previous studies, significantly higher CPD values are measured when imaging at a frequency of 2.5 MHz, as compared to imaging at 3 MHz. In conclusion, these results confirm the applicability of the discussed CPD as a marker for contrast imaging. Comparison with standard contrast-enhanced ultrasound imaging modalities will be the focus of future work.

  4. Dynamic Contrast-Enhanced MRI Evaluation of Cerebral Cavernous Malformations

    PubMed Central

    Hart, B. L.; Taheri, S.; Rosenberg, G. A.; Morrison, L. A.

    2013-01-01

    The aim of this study is to quantitatively evaluate the behavior of CNS cavernous malformations (CCMs) using a dynamic contrast-enhanced MRI (DCEMRI) technique sensitive for slow transfer rates of gadolinium. The prospective study was approved by the institutional review board and was HIPPA compliant. Written informed consent was obtained from 14 subjects with familial CCMs (4 men and 10 women, ages 22–76 years, mean 48.1 years). Following routine anatomic MRI of the brain, DCEMRI was performed for six slices, using T1 mapping with partial inversion recovery (TAPIR) to calculate T1 values, following administration of 0.025 mmol/kg gadolinium DTPA. The transfer rate (Ki) was calculated using the Patlak model, and Ki within CCMs was compared to normal-appearing white matter as well as to 17 normal control subjects previously studied. All subjects had typical MRI appearance of CCMs. Thirty-nine CCMs were studied using DCEMRI. Ki was low or normal in 12 lesions and elevated from 1.4 to 12 times higher than background in the remaining 27 lesions. Ki ranged from 2.1E–6 to 9.63E–4 min−1, mean 3.55E–4. Normal-appearing white matter in the CCM patients had a mean Ki of 1.57E–4, not statistically different from mean WM Ki of 1.47E–4 in controls. TAPIR-based DCEMRI technique permits quantifiable assessment of CCMs in vivo and reveals considerable differences not seen with conventional MRI. Potential applications include correlation with biologic behavior such as lesion growth or hemorrage, and measurement of drug effects. PMID:24323376

  5. Cumulative phase delay imaging - A new contrast enhanced ultrasound modality

    NASA Astrophysics Data System (ADS)

    Demi, Libertario; van Sloun, Ruud J. G.; Wijkstra, Hessel; Mischi, Massimo

    2015-10-01

    Recently, a new acoustic marker for ultrasound contrast agents (UCAs) has been introduced. A cumulative phase delay (CPD) between the second harmonic and fundamental pressure wave field components is in fact observable for ultrasound propagating through UCAs. This phenomenon is absent in the case of tissue nonlinearity and is dependent on insonating pressure and frequency, UCA concentration, and propagation path length through UCAs. In this paper, ultrasound images based on this marker are presented. The ULA-OP research platform, in combination with a LA332 linear array probe (Esaote, Firenze Italy), were used to image a gelatin phantom containing a PVC plate (used as a reflector) and a cylindrical cavity measuring 7 mm in diameter (placed in between the observation point and the PVC plate). The cavity contained a 240 µL/L SonoVueO® UCA concentration. Two insonating frequencies (3 MHz and 2.5 MHz) were used to scan the gelatine phantom. A mechanical index MI = 0.07, measured in water at the cavity location with a HGL-0400 hydrophone (Onda, Sunnyvale, CA), was utilized. Processing the ultrasound signals backscattered from the plate, ultrasound images were generated in a tomographic fashion using the filtered back-projection method. As already observed in previous studies, significantly higher CPD values are measured when imaging at a frequency of 2.5 MHz, as compared to imaging at 3 MHz. In conclusion, these results confirm the applicability of the discussed CPD as a marker for contrast imaging. Comparison with standard contrast-enhanced ultrasound imaging modalities will be the focus of future work.

  6. Contrast-enhanced ultrasound for liver imaging: recent advances.

    PubMed

    Salvatore, Veronica; Borghi, Alberto; Piscaglia, Fabio

    2012-01-01

    Contrast-enhanced ultrasonography (CEUS), providing relevant informations not available with non-enhanced ultrasonography, greatly impacted the practice of liver imaging. The characterization of focal liver lesions (FLLs), is obtained in a rapid, accurate and safe way and is considered the main hepatic indication; however CEUS offers other established or emergent relevant applications. Metastases detection and assessment of response to locoregional tumor treatment are accepted applications with specific indications. Needle guidance in case of poorly or non visible target lesions at conventional ultrasound is also accepted. The early assessment of response to systemic treatment, and in particular to antiangiogenic ones, by quantification software is an emergent application. The manageability of CEUS determined also its use in the operating theatre, improving the accuracy of intraoperatory US with a significant impact on final surgical strategy. In cirrhotic patients, the role of CEUS was proven highly accurate and sensitive in the characterization of portal vein thrombosis, by identification of contrast arterial enhancement inside the thrombus, that occurs only in case of neoplastic origin. In recent years microbubbles taken up by Kupffer cells, thus possessing a "postvascular" phase, were registered as ultrasound contrast agent in Japan (Sonazoid). During the post-vascular phase tumoral tissue tend to appear as a contrast defect image due to the lack of Kupffer cells, strongly contributing to tumor staging beside characterization. Newly developed techniques, such as fusion imaging or real-time three dimensional US, in addition to other applications of CEUS, in terms of post-transplantation or cholecystitis-related complications, have been recently proposed and will be discussed.

  7. Contrast-enhanced Ultrasound Imaging of Antiangiogenic Tumor Therapy.

    PubMed

    Klotz, Laura V; Clevert, Dirk-Andre; Scheckinger, Siiri; Strieth, Sebastian; Eichhorn, Martin E

    2015-05-01

    Anti-angiogenic treatment is a promising strategy for cancer therapy and is currently evaluated in clinical trials. The aim of the present study was to further investigate the effects of an anti-angiogenic therapy, inhibiting vascular endothelial growth factor (VEGF) and endothelial growth factor (EGF) using a tyrosine kinase inhibitor for blocking tumor angiogenesis and tumor progression in vivo. Experiments were performed using C57/Bl6 mice (25 ± 5 g of body weight (b.w.)) implanted with subcutaneous Lewis lung carcinoma (LLC-1). From day 7 till 21 after tumor cell implantation, animals (n=7 per group) were treated by monotherapy using ZD6474 (50 mg/kg b.w. per os (p.o.)) daily. A control group received only the solvent polysorbate 80. Using contrast enhanced ultrasound (CE-US) parameters of intra-tumoral microcirculation animals were examined 24 h after the last application of ZD6474. Moreover, subcutaneous tumor growth was measured over the whole therapy period. Finally, histological analyses were performed to analyze the functional vessel density in the tumor tissue. ZD6474 reduced tumor growth of LLC-1 in C57/Bl6 mice significantly. A significant difference of maximal signal intensity (ΔSImax) and area below the intensity time curve (AUC) after antiangiogenic therapy was recorded in the tumor center by CE-US. Vessel density after hematoxyline and eosin, as well as CD31, staining showed no significant difference in both groups. Anti-angiogenic effects can be quantitatively demonstrated using CE-US imaging, which represents the spreading of efficient vessels in the tumor tissue, especially in the tumor center. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  8. Contrast-enhanced photoacoustic imaging of live lobster nerve cord

    NASA Astrophysics Data System (ADS)

    Witte, Russell S.; Huang, S.; Ashkenazi, S.; Kim, K.; O'Donnell, M.

    2007-02-01

    Photoacoustic imaging provides optical contrast with good penetration and high spatial resolution, making it an attractive tool for noninvasive neural applications. We chose a commercial dye (NK2761) commonly used for optical imaging of membrane potential to enhance photoacoustic images of the live lobster nerve cord. The abdominal segment of the nerve cord was excised, stained and positioned in a custom neural recording system, enabling electrical stimulation and recording of compound action potentials. Photoacoustic and pulse echo images were also collected using a commercial ultrasound scanner and a 10-MHz linear probe. A wavelength-tunable pulsed laser source (Surelite TM, 5 ns, ~15 mJ, 30 mJ/cm2) operating at 20 Hz produced photoacoustic waves. Longitudinal photoacoustic scans of a 25-mm segment of the excised nerve cord, including ganglionic and axonal processes, were collected and displayed every 7 seconds. Without the contrast agent, an average of 10 scans produced a peak photoacoustic signal 6 dB over background noise. An additional 29 dB was obtained after the nerve was submerged in the dye for 20 minutes. The gain decreased to 23 dB and 14 dB at 810 nm and 910 nm, respectively - consistent with the dye's optical absorbance measured using a portable spectrometer. The contrast-enhanced photoacoustic signal had a broad spectrum peaking at 4 MHz, and, after high pass filtering, images approached 200-μm spatial resolution. The hybrid imaging system, which provided several hours of electrical stimulation and recording, represents a robust testbed to develop novel photoacoustic contrast for neural applications.

  9. Sizing of Emboli in Flowing Blood Using Pulse Doppler Ultrasound and the Embolus-To Power Ratio.

    NASA Astrophysics Data System (ADS)

    Moehring, Mark Alan

    The embolus to blood ratio (EBR) theoretical model describing pulse Doppler ultrasound observations of emboli in flowing blood is summarized. The EBR model uses the backscattered signal power from blood in the Doppler sample volume as a reference from which to assess embolus size and composition. This EBR is independent of attenuation and reflection loss in intervening tissues between probe and bloodflow. An in vitro investigation is presented that tests the validity of the EBR model. The experimental apparatus includes a novel phantom for Doppler observation of circulating emboli and a Doppler system which uses 1.6 and 2.4 MHz concurrently for interrogation of an embolus. The phantom contains a tubeless flow conduit inside a polyacrylamide gel and a blood-mimicking fluid flowing in the conduit. Time series Doppler shift data which are gathered while polystyrene microsphere "emboli" transit the sample volume are post -processed to calculate the EBR on each embolic signature. EBR measurements from microspheres of three different diameters are summarized and shown to contain pronounced and systematic variability. The hypothesis is presented that this variability is due to a small speed of sound mismatch between the gel and the blood-mimicking fluid, a phenomenon anticipated in vivo. This speed of sound mismatch results in beam refraction and a non-uniformly insonated sample volume (thereby causing variability in embolus signatures). A three dimensional theoretical study is presented that models beam refraction resulting from speed of sound mismatch between the blood mimicking fluid and the surrounding gel. A Monte Carlo study of the EBR behavior in the presence of beam refraction is performed and yields similar results to the data obtained in vitro. This study is evidence that the experimental signal variability is due to speed of sound mismatch between blood-mimicking fluid and gel. A method of extracting embolus size from the dual frequency EBR data based on the

  10. The role of tissue harmonic imaging ultrasound combined with power Doppler ultrasound in the diagnosis of childhood febrile urinary tract infections.

    PubMed

    İlarslan, Nisa Eda Çullas; Fitöz, Ömer Suat; Öztuna, Derya Gökmen; Küçük, Nuriye Özlem; Yalçınkaya, Fatma Fatoş

    2015-06-01

    This study assessed the ability of tissue harmonic imaging ultrasound combined with power Doppler ultrasound in the detection of childhood febrile urinary tract infections in comparison with the gold standard reference method: Tc-99m dimercaptosuccinicacid renal cortical scintigraphy. This prospective study included 60 patients who were hospitalized with a first episode of febrile urinary tract infections. All children were examined with dimercaptosuccinicacid scan and tissue harmonic imaging ultrasound combined with power Doppler ultrasound within the first 3 days of admission. Signs indicative of acute infection were observed in 29 patients according to the results of tissue harmonic imaging ultrasound combined with power Doppler ultrasound while dimercaptosuccinicacid scan revealed abnormal findings in 33 patients. The sensitivity, specificity, positive predictive value and negative predictive value of tissue harmonic imaging combined with power Doppler ultrasound using dimercaptosuccinicacid scintigraphy as the reference method in patients diagnosed with first episode febrile urinary tract infections were calculated as 57.58% (95% confidence interval: 40.81%-72.76%); 62.96% (95% confidence interval: 44.23%-78.47%); 65.52% (95% confidence interval: 52.04%-77%); 54.84% (95% confidence interval: 41.54%-67.52%); respectively. Although current results exhibit inadequate success of power Doppler ultrasound, this practical and radiation-free method may soon be comprise a part of the routine ultrasonographic evaluation of febrile urinary tract infections of childhood if patients are evaluated early and under appropriate sedation.

  11. The role of tissue harmonic imaging ultrasound combined with power Doppler ultrasound in the diagnosis of childhood febrile urinary tract infections

    PubMed Central

    İlarslan, Nisa Eda Çullas; Fitöz, Ömer Suat; Öztuna, Derya Gökmen; Küçük, Nuriye Özlem; Yalçınkaya, Fatma Fatoş

    2015-01-01

    Aim: This study assessed the ability of tissue harmonic imaging ultrasound combined with power Doppler ultrasound in the detection of childhood febrile urinary tract infections in comparison with the gold standard reference method: Tc-99m dimercaptosuccinicacid renal cortical scintigraphy. Material and Methods: This prospective study included 60 patients who were hospitalized with a first episode of febrile urinary tract infections. All children were examined with dimercaptosuccinicacid scan and tissue harmonic imaging ultrasound combined with power Doppler ultrasound within the first 3 days of admission. Results: Signs indicative of acute infection were observed in 29 patients according to the results of tissue harmonic imaging ultrasound combined with power Doppler ultrasound while dimercaptosuccinicacid scan revealed abnormal findings in 33 patients. The sensitivity, specificity, positive predictive value and negative predictive value of tissue harmonic imaging combined with power Doppler ultrasound using dimercaptosuccinicacid scintigraphy as the reference method in patients diagnosed with first episode febrile urinary tract infections were calculated as 57.58% (95% confidence interval: 40.81%–72.76%); 62.96% (95% confidence interval: 44.23%–78.47%); 65.52% (95% confidence interval: 52.04%–77%); 54.84% (95% confidence interval: 41.54%–67.52%); respectively. Conclusions: Although current results exhibit inadequate success of power Doppler ultrasound, this practical and radiation-free method may soon be comprise a part of the routine ultrasonographic evaluation of febrile urinary tract infections of childhood if patients are evaluated early and under appropriate sedation. PMID:26265892

  12. Comparison of power Doppler and thermography for the selection of thyroid nodules in which fine-needle aspiration biopsy is indicated*

    PubMed Central

    Alves, Maria Lucia D'Arbo; Gabarra, Manoel Henrique Cintra

    2016-01-01

    Objective To compare two methods-power Doppler and thermography-for the analysis of nodule vascularization and subsequent selection of nodules to be biopsied. Materials and Methods A total of 510 subjects with thyroid nodules were analyzed by power Doppler and submitted to fine-needle aspiration biopsy (FNAB). Thirty-seven patients were submitted to nodule excision (29 due to carcinoma or suspected carcinoma and 8 by patient choice). Among those patients, power Doppler had raised the suspicion of malignancy in 39 lesions, compared with 48 for FNAB. Another group, comprising 110 patients, underwent thermography, which raised the suspicion of malignancy in 124 thyroid nodules, as did FNAB. Malignant nodules were excised in all 110 of those patients (95 underwent nodulectomy and 15 underwent thyroidectomy), malignancy being confirmed by intraoperative examination of frozen biopsy samples. Results In relation to the FNAB findings, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of power Doppler were 95.16%, 23.52%, 96.22%, 16.70%, and 89.51%, respectively, compared with 100%, 58.06%, 87.73%, 100%, and 89.51%, respectively, for thermography. Conclusion Thermography was more precise than was power Doppler for the selection of thyroid nodules to be biopsied. PMID:27818545

  13. Very different performance of the power Doppler modalities of several ultrasound machines ascertained by a microvessel flow phantom.

    PubMed

    Ten Cate, David F; Luime, Jolanda J; van der Ven, Myrthe; Hazes, Johanna M W; Kooiman, Klazina; de Jong, Nico; Bosch, Johannes G

    2013-10-24

    In many patients with rheumatoid arthritis (RA) subclinical disease activity can be detected with ultrasound (US), especially using power Doppler US (PDUS). However, PDUS may be highly dependent on the type of machine. This could create problems both in clinical trials and in daily clinical practice. To clarify how the PDUS signal differs between machines we created a microvessel flow phantom. The flow phantom contained three microvessels (150, 1000, 2000 microns). A syringe pump was used to generate flows. Five US machines were used. Settings were optimised to assess the lowest detectable flow for each US machine. The minimal detectable flow velocities showed very large differences between the machines. Only two of the machines may be able to detect the very low flows in the capillaries of inflamed joints. There was no clear relation with price. One of the lower-end machines actually performed best in all three vessel sizes. We created a flow phantom to test the sensitivity of US machines to very low flows in small vessels. The sensitivity of the power Doppler modalities of 5 different machines was very different. The differences found between the machines are probably caused by fundamental differences in processing of the PD signal or internal settings inaccessible to users. Machines considered for PDUS assessment of RA patients should be tested using a flow phantom similar to ours. Within studies, only a single machine type should be used.

  14. Very different performance of the power Doppler modalities of several ultrasound machines ascertained by a microvessel flow phantom

    PubMed Central

    2013-01-01

    Introduction In many patients with rheumatoid arthritis (RA) subclinical disease activity can be detected with ultrasound (US), especially using power Doppler US (PDUS). However, PDUS may be highly dependent on the type of machine. This could create problems both in clinical trials and in daily clinical practice. To clarify how the PDUS signal differs between machines we created a microvessel flow phantom. Methods The flow phantom contained three microvessels (150, 1000, 2000 microns). A syringe pump was used to generate flows. Five US machines were used. Settings were optimised to assess the lowest detectable flow for each US machine. Results The minimal detectable flow velocities showed very large differences between the machines. Only two of the machines may be able to detect the very low flows in the capillaries of inflamed joints. There was no clear relation with price. One of the lower-end machines actually performed best in all three vessel sizes. Conclusions We created a flow phantom to test the sensitivity of US machines to very low flows in small vessels. The sensitivity of the power Doppler modalities of 5 different machines was very different. The differences found between the machines are probably caused by fundamental differences in processing of the PD signal or internal settings inaccessible to users. Machines considered for PDUS assessment of RA patients should be tested using a flow phantom similar to ours. Within studies, only a single machine type should be used. PMID:24286540

  15. Modeling solar oscillation power spectra. II. Parametric model of spectral lines observed in Doppler-velocity measurements

    SciTech Connect

    Vorontsov, Sergei V.; Jefferies, Stuart M. E-mail: stuartj@ifa.hawaii.edu

    2013-11-20

    We describe a global parametric model for the observed power spectra of solar oscillations of intermediate and low degree. A physically motivated parameterization is used as a substitute for a direct description of mode excitation and damping as these mechanisms remain poorly understood. The model is targeted at the accurate fitting of power spectra coming from Doppler-velocity measurements and uses an adaptive response function that accounts for both the vertical and horizontal components of the velocity field on the solar surface and for possible instrumental and observational distortions. The model is continuous in frequency, can easily be adapted to intensity measurements, and extends naturally to the analysis of high-frequency pseudomodes (interference peaks at frequencies above the atmospheric acoustic cutoff).

  16. Contrast-enhanced optical coherence microangiography with acoustic-actuated microbubbles

    NASA Astrophysics Data System (ADS)

    Liu, Yu-Hsuan; Zhang, Jia-Wei; Yeh, Chih-Kuang; Wei, Kuo-Chen; Liu, Hao-Li; Tsai, Meng-Tsan

    2017-04-01

    In this study, we propose to use gas-filled microbubbles (MBs) simultaneously actuated by the acoustic wave to enhance the imaging contrast of optical coherence tomography (OCT)-based angiography. In the phantom experiments, MBs can result in stronger backscattered intensity, enabling to enhance the contrast of OCT intensity image. Moreover, simultaneous application of low-intensity acoustic wave enables to temporally induce local vibration of particles and MBs in the vessels, resulting in time-variant OCT intensity which can be used for enhancing the contrast of OCT intensitybased angiography. Additionally, different acoustic modes and different acoustic powers to actuate MBs are performed and compared to investigate the feasibility of contrast enhancement. Finally, animal experiments are performed. The findings suggest that acoustic-actuated MBs can effectively enhance the imaging contrast of OCT-based angiography and the imaging depth of OCT angiography is also extended.

  17. Contrast-enhanced fluorodeoxyglucose positron emission tomography/contrast-enhanced computed tomography in mediastinal T-cell lymphoma with superior vena cava syndrome

    PubMed Central

    Santhosh, Sampath; Gorla, Arun Kumar Reddy; Bhattacharya, Anish; Varma, Subhash Chander; Mittal, Bhagwant Rai

    2016-01-01

    Positron emission tomography-computed tomography (PET/CT) is a routine investigation for the staging of lymphomas. Contrast-enhanced computed tomography is mandatory whenever parenchymal lesions, especially in the liver and spleen are suspected. We report a rare case of primary mediastinal T-cell lymphoma evaluated with contrast-enhanced PET/CT that showed features of superior vena cava syndrome. PMID:26917907

  18. Contrast-enhanced endobronchial ultrasound: Potential value of a new method

    PubMed Central

    Dietrich, Christoph F.

    2017-01-01

    Endobronchial ultrasound (EBUS) has gained importance for mediastinal lymph node staging. Contrast-enhanced EBUS is so far not a discussed technique including contrast-enhanced high mechanical index (MI)-EBUS and potentially contrast-enhanced low MI-EBUS. Possible use could include characterization of mediastinal lymph nodes for better selection of biopsies, differential diagnosis of the primary tumor, and evaluation of thrombosis or tumor in vein infiltration. PMID:28218200

  19. Tissue Doppler imaging in cardiac sarcoidosis.

    PubMed

    Smedema, J P

    2008-07-01

    A middle-aged African lady, who presented with ventricular tachycardias, mitral valve regurgitation and congestive heart failure, was diagnosed with cardiac sarcoidosis. Tissue Doppler imaging demonstrated abnormalities suggestive of myocardial scar, which was confirmed by contrast-enhanced cardiac magnetic resonance.

  20. [Contrast-enhanced sonography. Therapy control of radiofrequency ablation and transarterial chemoembolization of hepatocellular carcinoma].

    PubMed

    Jung, E M; Uller, W; Stroszczynski, C; Clevert, D-A

    2011-06-01

    Due to the imaging of dynamic perfusion, hepatocellular carcinoma can be detected with a sensitivity of >90% using contrast-enhanced sonography. The characterization of liver tumors with contrast-enhanced sonography is comparable to the diagnostic accuracy of contrast-enhanced computed tomography. The dynamic detection of microvascularization with contrast-enhanced sonography allows the differentiation between vascularized tumors and non-vascularized necrotic lesions before, during and after transarterial chemoembolization or percutaneous radiofrequency ablation. Image fusion with volume navigation can be useful in the followup control.

  1. Fusion imaging of contrast-enhanced ultrasound and contrast-enhanced CT or MRI before radiofrequency ablation for liver cancers.

    PubMed

    Bo, Xiao-Wan; Xu, Hui-Xiong; Wang, Dan; Guo, Le-Hang; Sun, Li-Ping; Li, Xiao-Long; Zhao, Chong-Ke; He, Ya-Ping; Liu, Bo-Ji; Li, Dan-Dan; Zhang, Kun

    2016-11-01

    To investigate the usefulness of fusion imaging of contrast-enhanced ultrasound (CEUS) and CECT/CEMRI before percutaneous ultrasound-guided radiofrequency ablation (RFA) for liver cancers. 45 consecutive patients with 70 liver lesions were included between March 2013 and October 2015, and all the lesions were identified on CEMRI/CECT prior to inclusion in the study. Planning ultrasound for percutaneous RFA was performed using conventional ultrasound, ultrasound-CECT/CEMRI and CEUS and CECT/CEMRI fusion imaging during the same session. The numbers of the conspicuous lesions on ultrasound and fusion imaging were recorded. RFA was performed according to the results of fusion imaging. Complete response (CR) rate was calculated and the complications were recorded. On conventional ultrasound, 25 (35.7%) of the 70 lesions were conspicuous, whereas 45 (64.3%) were inconspicuous. Ultrasound-CECT/CEMRI fusion imaging detected additional 24 lesions thus increased the number of the conspicuous lesions to 49 (70.0%) (70.0% vs 35.7%; p < 0.001 in comparison with conventional ultrasound). With the use of CEUS and CECT/CEMRI fusion imaging, the number of the conspicuous lesions further increased to 67 (95.7%, 67/70) (95.7% vs 70.0%, 95.7% vs 35.7%; both p < 0.001 in comparison with ultrasound and ultrasound-CECT/CEMRI fusion imaging, respectively). With the assistance of CEUS and CECT/CEMRI fusion imaging, the confidence level of the operator for performing RFA improved significantly with regard to visualization of the target lesions (p = 0.001). The CR rate for RFA was 97.0% (64/66) in accordance to the CECT/CEMRI results 1 month later. No procedure-related deaths and major complications occurred during and after RFA. Fusion of CEUS and CECT/CEMRI improves the visualization of those inconspicuous lesions on conventional ultrasound. It also facilitates improvement in the RFA operators' confidence and CR of RFA. Advances in knowledge: CEUS and CECT/CEMRI fusion imaging

  2. Individually tailored contrast enhancement in CT pulmonary angiography

    PubMed Central

    Hendriks, Babs M F; Kok, Madeleine; Mihl, Casper; Bekkers, Sebastiaan C A M; Wildberger, Joachim E

    2016-01-01

    Objective: The purpose was to evaluate individually shaped contrast media (CM) delivery in CT pulmonary angiography (CTPA) for suspected pulmonary embolism (PE). Methods: 100 consecutive emergency patients with clinical suspicion of PE were evaluated. High-pitch CTPA was performed on a second-generation dual-source CT using the following parameters: 100 kV, 200–250 mAsref, rotation time 0.28 s, 128 × 0.6 mm col. and image reconstruction 1.0/0.8 mm (B30f). Group 1 (n = 50) then received a fixed CM bolus (300 = mgI ml−1, volume = 90 ml and flow rate = 6 ml s−1); Group 2 (n = 50) received a body weight-adapted CM bolus determined by dedicated contrast injection software. For analysis, groups were further subdivided into low-weight (40–75 kg) and high-weight (76–117 kg) groups. Technical image quality was graded using a four-point Likert scale (1 = non-diagnostic; 2 = diagnostic; 3 = good and 4 = excellent image quality) at the level of the pulmonary trunk and pulmonary arteries. Objective image quality analysis was performed by measuring contrast enhancement in Hounsfield units (HU) at the same levels. Attenuation levels > 180 HU were considered diagnostic. Results: All examinations were graded as diagnostic at each level. The individual minimum pulmonary attenuation was 184 and 270 HU for Group 1 and 2, respectively. Mean attenuation was as follows: Group 1: 475 ± 105 HU (40–75 kg) and 402 ± 115 HU (76–117 kg), p < 0.03. Group 2: 424 ± 76 HU (40–75 kg) and 418 ± 100 HU (76–117 kg), p = 0.8. For Group 2, CM volumes were: 55 ± 5 ml (40–75 kg) and 66 ± 5 ml (76–117 kg), leading to 16–51% CM reduction. Conclusion: Even under emergency conditions, individualized CM protocols can provide diagnostic and robust image quality in CTPA for PE with a substantial reduction of CM volume for lower weight patients, compared with

  3. Imaging features of hepatic angiomyolipomas on real-time contrast-enhanced ultrasound

    PubMed Central

    Wang, Z; Xu, H-X; Xie, X-Y; Xie, X-H; Kuang, M; Xu, Z-F; Liu, G-J; Chen, L-D; Lin, M-X; Lu, M-D

    2010-01-01

    The aim of this study was to evaluate the imaging features of hepatic angiomyolipoma (AML) on contrast-enhanced ultrasound (CEUS). The imaging features of 12 pathologically proven hepatic AML lesions in 10 patients who had undergone baseline ultrasound (BUS) and CEUS examinations were evaluated retrospectively. The enhancement extent, pattern and dynamic change, along with the enhancement process, on CEUS were analysed. The diagnostic results of BUS and CEUS before pathological examination were also recorded. The results showed that 75% (9/12) of the AML lesions exhibited mixed echogenicity on BUS and most showed remarkable hyperechogenicity in combination with a hypoechoic or anechoic portion. Arterial flow signals were detected in 75% (9/12) of the lesions on colour Doppler imaging. On CEUS, 66.7% (n = 8) of the 12 lesions exhibited hyperenhancement in the arterial phase, slight hyperenhancement (n = 2) or isoenhancement (n = 6) in the portal phase, and slight hyperenhancement (n = 1) or isoenhancement (n = 7) in the late phase. Three (25%) lesions exhibited hyperenhancement in the arterial phase and hypoenhancement in both portal and late phases. One (8.3%) lesion exhibited hypoenhancement throughout the CEUS process. Before pathological examination with BUS, only 3 (25%) lesions were correctly diagnosed as hepatic AML. Conversely, on CEUS, correct diagnoses were made for 66.8% (8/12) of hepatic AMLs. Therefore, arterial hyperenhancement and subsequent sustained enhancement on CEUS were found in the majority of hepatic AMLs. The combination of BUS and CEUS leads to the correct diagnosis in the majority of hepatic AMLs, and is higher than the success rate achieved by BUS alone. PMID:19723766

  4. Impact of contrast-enhanced ultrasound in patients with renal function impairment

    PubMed Central

    Girometti, Rossano; Stocca, Tiziano; Serena, Elena; Granata, Antonio; Bertolotto, Michele

    2017-01-01

    AIM To investigate the role of contrast enhanced ultrasound (CEUS) in evaluating patients with renal function impairment (RFI) showing: (1) acute renal failure (ARF) of suspicious vascular origin; or (2) suspicious renal lesions. METHODS We retrospectively evaluated patients addressed to CEUS over an eight years period to rule-out vascular causes of ARF (first group of 50 subjects) or assess previously found suspicious renal lesions (second group of 41 subjects with acute or chronic RFI). After preliminary grey-scale and color Doppler investigation, each kidney was investigated individually with CEUS, using 1.2-2.4 mL of a sulfur hexafluoride-filled microbubble contrast agent. Image analysis was performed in consensus by two readers who reviewed digital clips of CEUS. We calculated the detection rate of vascular abnormalities in the first group and performed descriptive statistics of imaging findings for the second group. RESULTS In the first group, CEUS detected renal infarction or cortical ischemia in 18/50 patients (36%; 95%CI: 23.3-50.9) and 1/50 patients (2%; 95%CI: 0.1-12), respectively. The detection rate of infarction was significantly higher (P = 0.0002; McNemar test) compared to color Doppler ultrasonography (10%). No vascular causes of ARF were identified in the remaining 31/50 patients (62%). In the second group, CEUS detected 41 lesions on 39 patients, allowing differentiation between solid lesions (21/41; 51.2%) vs complex cysts (20/41; 48.8%), and properly addressing 15/39 patients to intervention when feasible based on clinical conditions (surgery and cryoablation in 13 and 2 cases, respectively). Cysts were categorized Bosniak II, IIF, III and IV in 8, 5, 4 and 3 cases, respectively. In the remaining two patients, CEUS found 1 pseudolesion and 1 subcapsular hematoma. CONCLUSION CEUS showed high detection rate of renal perfusion abnormalities in patients with ARF, influencing the management of patients with acute or chronic RFI and renal masses

  5. Contrast-enhanced transrectal ultrasonography for the detection of diffuse prostate cancer.

    PubMed

    Gao, Y; Liao, X H; Lu, L; Wang, L; Ma, Y; Qin, H Z; Yan, X; Guo, P

    2016-03-01

    To evaluate the diagnostic accuracy of contrast-enhanced transrectal ultrasonography (CE-TRUS) versus baseline TRUS (combination of grey-scale and colour Doppler imaging) for diffuse prostate cancer. Forty-six patients without an obvious focal mass on baseline TRUS (grey-scale and colour Doppler), underwent additional CE-TRUS and TRUS-guided biopsy due to elevated levels of prostate-specific antigen (PSA ≥4 ng/ml) and/or abnormal digital rectal examination (DRE). In all patients, CE-TRUS was performed with intravenous injection of a contrast agent (sulphur hexafluoride microbubble; SonoVue, 2.4 ml) before biopsy. TRUS-guided biopsy targeted suspicious areas detected on CE-TRUS imaging or sampled the outer gland of the normal prostate. The final diagnosis was based on results of the TRUS-guided biopsy. The diagnostic accuracy of baseline TRUS and CE-TRUS for diffuse prostatic lesions was evaluated using receiver operating characteristic (ROC) curve analysis. Diffuse prostate cancer was present in 32 (69.5%) patients and absent in 14 (30.5%) patients. Nineteen patients had diffuse prostate cancer that was not detected by baseline TRUS, whereas 15 cases were identified using CE-TRUS. Conversely, five patients had benign prostatic hypertrophy (BPH) that was diagnosed as cancer by CE-TRUS, and two of these patients were diagnosed with BPH by baseline TRUS. The combined sensitivity, specificity, and accuracy were 87.5%, 64.2%, and 80.4%, respectively, for CE-TRUS, and 40.6%, 78.5%, and 52.1%, respectively, for baseline TRUS. The area under the ROC curve (AUC) values for the diagnostic accuracy of baseline CE-TRUS versus TRUS for diffuse prostate cancer differed significantly at 0.904 and 0.667, respectively (Z=4.098, p<0.0001). CE-TRUS exhibited greater diagnostic accuracy for diffuse prostate cancer than baseline TRUS. CE-TRUS may improve cancer detection over baseline TRUS imaging for the diagnosis of diffuse prostate cancer in patients with an elevated PSA level. CE

  6. Quantitative Evaluation of Vascularity Using 2-D Power Doppler Ultrasonography May Not Identify Malignancy of the Thyroid.

    PubMed

    Yoon, Jung Hyun; Shin, Hyun Joo; Kim, Eun-Kyung; Moon, Hee Jung; Roh, Yun Ho; Kwak, Jin Young

    2015-11-01

    The purpose of this study was to evaluate the usefulness of a quantitative vascular index in predicting thyroid malignancy. A total of 1309 thyroid nodules in 1257 patients (mean age: 50.2 y, range: 18-83 y) were included. The vascularity pattern and vascular index (VI) measured by quantification software for each nodule were obtained from 2-D power Doppler ultrasonography (US). Gray-scale US + vascularity pattern was compared with gray-scale US + VI with respect to diagnostic performance. Of the 1309 thyroid nodules, 927 (70.8%) were benign and 382 (29.2%) were malignant. The area under the receiver operating characteristics curve (Az) for gray-scale US (0.82) was significantly higher than that for US combined with vascularity pattern (0.77) or VI (0.70, all p < 0.001). Quantified VIs were higher in benign nodules, but did not improve the performance of 2-D US in diagnosing thyroid malignancy.

  7. Three-dimensional power Doppler ultrasound diagnosis and laparoscopic management of a pregancy in a previous cesarean scar.

    PubMed

    Wang, Chin-Jung; Yuen, Leung-To; Yen, Chih-Feng; Lee, Chyi-Long; Soong, Yung-Kuei

    2004-12-01

    An ectopic pregnancy developing in a previous Cesarean section scar is a rare event, and there is still a lack of information concerning the adequacy of management strategies. So far, no modality can guarantee the integrity of the uterus. We report the case of a 29-year-old woman with three Cesarean deliveries who was transferred to our hospital with a diagnosis of cervical pregnancy. Transvaginal three-dimensional power Doppler ultrasound revealed a well-encapsulated bulging mass displacing anteriorly over the lower anterior uterine wall sounding with an irregular course and branching vessels. The diagnosis of pregnancy in a previous Cesarean scar was made. Laparoscopic ligation of bilateral uterine arteries followed by excision of the ectopic pregnant mass was undertaken, and the patient's uterus was successfully preserved. Conservative management with the laparoscopic approach may be a safe and effective alternative to hysterectomy in patients with a pregnacy in a previous Cesarean scar.

  8. Imaging of myocardial infarction using carbon nanotube micro-computed tomography and delayed contrast enhancement

    NASA Astrophysics Data System (ADS)

    Burk, Laurel M.; Wang, Kohan; Kang, Eunice; Rojas, Mauricio; Willis, Monte; Lee, Yueh Z.; Lu, Jianping; Zhou, Otto

    2011-03-01

    We demonstrate the application of our cardiac- and respiratory-gated carbon nanotube (CNT) micro-CT system by evaluating murine myocardial infarction models with a delayed contrast enhancement technique. Myocardial infarction was induced in 8 wild-type male mice. The ischemia reperfusion model was achieved by surgical occlusion of the LAD artery for 30 minutes followed by 24 hours of reperfusion. Free-breathing subjects were anesthetized with isoflurane during imaging. Respiratory and cardiac signals were monitored externally to gate the scan. Micro-CT data was obtained at 50kV, 3mA cathode current for 15ms per projection. All images were acquired during end exhalation at either 0msec or 55msec after the R-wave (diastole or systole, respectively). Following administration of Omnipaque 300mgI/mL at 0.1ml/5g, images were obtained at 0msec after the R-wave. Fenestra VC was then administered at a 0.1ml/5g dose, followed by images 0 and 55msec after the R-wave. Hearts were then harvested, sliced 1mm thick and stained with TTC. All animals survived surgery and imaging; all demonstrated obvious delayed contrast enhancement in the left ventricular wall in Omnipaque images. Fenestra VC revealed cardiac functional changes quantified by low ejection fractions. All subjects demonstrated areas of myocardial infarct in the LAD distribution on both TTC staining and micro-CT imaging. CNT enabled gated cardiac micro-CT imaging demonstrates the ability to consistently identify areas of myocardial infarct in mice, providing a powerful tool for the study of cardiovascular biology. Further work is ongoing to streamline the imaging protocol and perform more quantitative analysis of the images.

  9. Automated assessment of joint synovitis activity from medical ultrasound and power doppler examinations using image processing and machine learning methods.

    PubMed

    Cupek, Rafal; Ziębiński, Adam

    2016-01-01

    Rheumatoid arthritis is the most common rheumatic disease with arthritis, and causes substantial functional disability in approximately 50% patients after 10 years. Accurate measurement of the disease activity is crucial to provide an adequate treatment and care to the patients. The aim of this study is focused on a computer aided diagnostic system that supports an assessment of synovitis severity. This paper focus on a computer aided diagnostic system that was developed within joint Polish-Norwegian research project related to the automated assessment of the severity of synovitis. Semiquantitative ultrasound with power Doppler is a reliable and widely used method of assessing synovitis. Synovitis is estimated by ultrasound examiner using the scoring system graded from 0 to 3. Activity score is estimated on the basis of the examiner's experience or standardized ultrasound atlases. The method needs trained medical personnel and the result can be affected by a human error. The porotype of a computer-aided diagnostic system and algorithms essential for an analysis of ultrasonic images of finger joints are main scientific output of the MEDUSA project. Medusa Evaluation System prototype uses bone, skin, joint and synovitis area detectors for mutual structural model based evaluation of synovitis. Finally, several algorithms that support the semi-automatic or automatic detection of the bone region were prepared as well as a system that uses the statistical data processing approach in order to automatically localize the regions of interest. Semiquantitative ultrasound with power Doppler is a reliable and widely used method of assessing synovitis. Activity score is estimated on the basis of the examiner's experience and the result can be affected by a human error. In this paper we presented the MEDUSA project which is focused on a computer aided diagnostic system that supports an assessment of synovitis severity.

  10. Automated assessment of joint synovitis activity from medical ultrasound and power doppler examinations using image processing and machine learning methods

    PubMed Central

    Ziębiński, Adam

    2016-01-01

    Objectives Rheumatoid arthritis is the most common rheumatic disease with arthritis, and causes substantial functional disability in approximately 50% patients after 10 years. Accurate measurement of the disease activity is crucial to provide an adequate treatment and care to the patients. The aim of this study is focused on a computer aided diagnostic system that supports an assessment of synovitis severity. Material and methods This paper focus on a computer aided diagnostic system that was developed within joint Polish–Norwegian research project related to the automated assessment of the severity of synovitis. Semiquantitative ultrasound with power Doppler is a reliable and widely used method of assessing synovitis. Synovitis is estimated by ultrasound examiner using the scoring system graded from 0 to 3. Activity score is estimated on the basis of the examiner’s experience or standardized ultrasound atlases. The method needs trained medical personnel and the result can be affected by a human error. Results The porotype of a computer-aided diagnostic system and algorithms essential for an analysis of ultrasonic images of finger joints are main scientific output of the MEDUSA project. Medusa Evaluation System prototype uses bone, skin, joint and synovitis area detectors for mutual structural model based evaluation of synovitis. Finally, several algorithms that support the semi-automatic or automatic detection of the bone region were prepared as well as a system that uses the statistical data processing approach in order to automatically localize the regions of interest. Conclusions Semiquantitative ultrasound with power Doppler is a reliable and widely used method of assessing synovitis. Activity score is estimated on the basis of the examiner’s experience and the result can be affected by a human error. In this paper we presented the MEDUSA project which is focused on a computer aided diagnostic system that supports an assessment of synovitis severity

  11. Nanoparticle Based Contrast Enhancement for Discriminating Indolent From Aggressive Prostate Cancer

    DTIC Science & Technology

    2016-06-01

    AWARD NUMBER: W81XWH-15-1-0102 TITLE: Nanoparticle -Based Contrast Enhancement for Discriminating Indolent From Aggressive Prostate Cancer...2016 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Nanoparticle -Based Contrast Enhancement for Discriminating Indolent From Aggressive Prostate Cancer 5b...followed through watchful waiting or active surveillance management. Specifically, we aim to image metallic and polymer nanoparticles as they

  12. Development of contrast enhancing agents in magnetic resonance imaging.

    PubMed

    Lex, L

    1989-01-01

    Magnetic Resonance Imaging (MRI) is a powerful new diagnostic tool in medicine. In MRI there is a great need to improve the specific identification of different tissues i.e. to enhance the contrast between them. This review tries to cover most of the approaches known for solving this problem.

  13. [Value of quantitative measurement of placenta with three-dimensional power Doppler ultrasonography in pregnant women with pregnancy-induced hypertension].

    PubMed

    Yang, Ruiqi; Zhang, Jialing; Zhu, Chonglei; Wang, Fei; Fan, Limei

    2015-08-18

    To evaluate the intrauterine state of fetuses with pregnancy-induced hypertension (PIH) through quantitative measurement of placenta by three-dimensional power Doppler ultrasonography, and to judge the value of three-dimensional power Doppler in PIH fetuses. A total of 50 pregnant women with PIH in our hospital from November 2012 to August 2014 were enrolled into the observation group, while 50 cases were randomly selected into the control group to match the former group's gestational week (GA). The placental vascularization index (VI), flow index (FI) and vascularization flow index (VFI) were quantitatively measured by three-dimensional power Doppler ultrasonography in the two groups. SPSS 19 statistics software was used to do the linear regression for the above parameters.And those parameters of the two groups were compared by t test. P<0.05 was deemed significant. The detection ratio of fetal placental VI, FI and VFI of the whole 100 cases was 100%. The regression equation of VI and GA was: Y=0.394X-5.358, R² = 0.694, P<0.05; the regression equation of FI and GA was: Y=0.801X+5.61, R² = 0.807, P<0.05; the regression equation of VFI and GA was: Y=0.225X-4.148, R² = 0.691, P<0.05. t tests showed the differences of the means of placental VI, FI and VFI between the observation group and the control group were statistically significant (all P<0.05). VI, FI and VFI of placenta measured by three-dimensional power Doppler examination increase with the increase of GA, and the means of placental VI, FI and VFI in PIH patients are less than those in normal cases. Quantitative measurement of placenta with three-dimensional power Doppler ultrasound has its own advantages, and can evaluate the status of placenta of PIH fetus accurately.

  14. Renal Masses With Equivocal Enhancement at CT: Characterization With Contrast-Enhanced Ultrasound.

    PubMed

    Bertolotto, Michele; Cicero, Calogero; Perrone, Rosaria; Degrassi, Ferruccio; Cacciato, Francesca; Cova, Maria A

    2015-05-01

    The purpose of this article is to retrospectively investigate in two radiology centers the role of contrast-enhanced ultrasound in the characterization of renal masses with equivocal enhancement at CT (i.e., with a density increase of 10-20 HU between unenhanced and contrast-enhanced scans) not characterized with conventional ultrasound modes. Forty-seven renal lesions (range, 0.8-7.7 cm; average, 2.6 cm) with equivocal enhancement at CT underwent contrast-enhanced ultrasound using sulfur hexafluoride-filled microbubbles. Examinations were digitally recorded for retrospective blinded evaluation by two radiologists with 20 and 10 years' experience in urologic imaging. Histologic results were available for 30 of 47 (64%) lesions (25 primary malignant tumors, two metastases, and three primary benign lesions). Two lesions increased in size and complexity during the follow-up and were considered malignant. One Bosniak category III and 14 category IIF cysts were stable after a follow-up of at least 3 years and were considered benign. ROC curve analysis was used to assess the capability of contrast-enhanced ultrasound to differentiate benign from malignant lesions. Twelve likely complex cystic lesions at gray-scale ultrasound were cystic also on contrast-enhanced ultrasound and reference procedures. Eleven of 34 lesions that appeared solid at gray-scale ultrasound were cystic on contrast-enhanced ultrasound and reference procedures. One lesion considered likely solid by one radiologist and possibly cystic by the other was a solid tumor at contrast-enhanced ultrasound and histologic analysis. The diagnostic performance of contrast-enhanced ultrasound to characterize the lesions as benign or malignant was high for both readers (AUC, 0.958 and 0.966, respectively). Contrast-enhanced ultrasound is effective for characterizing renal lesions presenting with equivocal enhancement at CT.

  15. Evaluation of Acoustic Doppler Current Profiler to Measure Discharge at New York Power Authority's Niagara Power Project, Niagara Falls, New York

    USGS Publications Warehouse

    Zajd, Henry J.

    2007-01-01

    The need for accurate real-time discharge in the International Niagara River hydro power system requires reliable, accurate and reproducible data. The U.S. Geological Survey has been widely using Acoustic Doppler Current Profilers (ADCP) to accurately measure discharge in riverine channels since the mid-1990s. The use of the ADCP to measure discharge has remained largely untested at hydroelectric-generation facilities such as the New York Power Authority's (NYPA) Niagara Power Project in Niagara Falls, N.Y. This facility has a large, engineered diversion channel with the capacity of high volume discharges in excess of 100,000 cubic feet per second (ft3/s). Facilities such as this could benefit from the use of an ADCP, if the ADCP discharge measurements prove to be more time effective and accurate than those obtained from the flow-calculation techniques that are currently used. Measurements of diversion flow by an ADCP in the 'Pant Leg' diversion channel at the Niagara Power Project were made on November 6, 7, and 8, 2006, and compared favorably (within 1 percent) with those obtained concurrently by a conventional Price-AA current-meter measurement during one of the ADCP measurement sessions. The mean discharge recorded during each 2-hour individual ADCP measurement session compared favorably with (3.5 to 6.8 percent greater than) the discharge values computed by the flow-calculation method presently in use by NYPA. The use of ADCP technology to measure discharge could ultimately permit increased power-generation efficiency at the NYPA Niagara Falls Power Project by providing improved predictions of the amount of water (and thus the power output) available.

  16. Confident diagnosis of bronchobiliary fistula using contrast-enhanced magnetic resonance cholangiography.

    PubMed

    Karabulut, Nevzat; Cakmak, Vefa; Kiter, Göksel

    2010-01-01

    We report the utility of contrast-enhanced magnetic resonance cholangiography (MRC) using gadoxetic acid (Gd-EOB-DTPA) in the diagnosis of bronchobiliary fistula associated with liver hydatid cyst. Contrast-enhanced MRC clearly delineated the leakage of contrast agent from the biliary duct and its communication with the bronchial tree. Providing functional information about physiologic or pathologic biliary flow in addition to the display of biliary anatomy, contrast-enhanced MRC stands as a robust technique in confidently detecting bronchobiliary fistula and bile leaks.

  17. Assessment of mass detection performance in contrast enhanced digital mammography

    NASA Astrophysics Data System (ADS)

    Carton, Ann-Katherine; de Carvalho, Pablo M.; Li, Zhijin; Dromain, Clarisse; Muller, Serge

    2015-03-01

    We address the detectability of contrast-agent enhancing masses for contrast-agent enhanced spectral mammography (CESM), a dual-energy technique providing functional projection images of breast tissue perfusion and vascularity using simulated CESM images. First, the realism of simulated CESM images from anthropomorphic breast software phantoms generated with a software X-ray imaging platform was validated. Breast texture was characterized by power-law coefficients calculated in data sets of real clinical and simulated images. We also performed a 2-alternative forced choice (2-AFC) psychophysical experiment whereby simulated and real images were presented side-by-side to an experienced radiologist to test if real images could be distinguished from the simulated images. It was found that texture in our simulated CESM images has a fairly realistic appearance. Next, the relative performance of human readers and previously developed mathematical observers was assessed for the detection of iodine-enhancing mass lesions containing different contrast agent concentrations. A four alternative-forced-choice (4 AFC) task was designed; the task for the model and human observer was to detect which one of the four simulated DE recombined images contained an iodineenhancing mass. Our results showed that the NPW and NPWE models largely outperform human performance. After introduction of an internal noise component, both observers approached human performance. The CHO observer performs slightly worse than the average human observer. There is still work to be done in improving model observers as predictors of human-observer performance. Larger trials could also improve our test statistics. We hope that in the future, this framework of software breast phantoms, virtual image acquisition and processing, and mathematical observers can be beneficial to optimize CESM imaging techniques.

  18. Assessment of arterial stenosis in a flow model with power Doppler angiography: accuracy and observations on blood echogenicity.

    PubMed

    Cloutier, G; Qin, Z; Garcia, D; Soulez, G; Oliva, V; Durand, L G

    2000-11-01

    The objective of the project was to study the influence of various hemodynamic and rheologic factors on the accuracy of 3-D power Doppler angiography (PDA) for quantifying the percentage of area reduction of a stenotic artery along its longitudinal axis. The study was performed with a 3-D power Doppler ultrasound (US) imaging system and an in vitro mock flow model containing a simulated artery with a stenosis of 80% area reduction. Measurements were performed under steady and pulsatile flow conditions by circulating, at different flow rates, four types of fluid (porcine whole blood, porcine whole blood with a US contrast agent, porcine blood cell suspension and porcine blood cell suspension with a US contrast agent). A total of 120 measurements were performed. Computational simulations of the fluid dynamics in the vicinity of the axisymmetrical stenosis were performed with finite-element modeling (FEM) to locate and identify the PDA signal loss due to the wall filter of the US instrument. The performance of three segmentation algorithms used to delineate the vessel lumen on the PDA images was assessed and compared. It is shown that the type of fluid flowing in the phantom affects the echoicity of PDA images and the accuracy of the segmentation algorithms. The type of flow (steady or pulsatile) and the flow rate can also influence the PDA image accuracy, whereas the use of US contrast agent has no significant effect. For the conditions that would correspond to a US scan of a common femoral artery (whole blood flowing at a mean pulsatile flow rate of 450 mL min(-1)), the errors in the percentages of area reduction were 4.3 +/- 1.2% before the stenosis, -2.0 +/- 1.0% in the stenosis, 11.5 +/- 3.1% in the recirculation zone, and 2.8 +/- 1.7% after the stenosis, respectively. Based on the simulated blood flow patterns obtained with FEM, the lower accuracy in the recirculation zone can be attributed to the effect of the wall filter that removes low flow velocities. In

  19. Power M-Mode Doppler and single-gate spectral analysis using a 2-MHz pulsed-wave Doppler transducer to directly detect cervical internal carotid artery stenosis: use of the continuity principle: report of a novel technique.

    PubMed

    Popa, Vasile N; Spencer, Merrill P; Lion, Charlene L; Felberg, Robert A

    2007-06-01

    We hypothesized that direct cervical investigation with Power M-Mode Doppler (PMD) combined with single-gate Doppler spectral analysis (SGDSA) using a 2-MHz pulsed-wave Doppler transducer would show reasonable accuracy parameters when compared with standard color-coded carotid duplex ultrasound (CDU). We prospectively screened for cervical internal carotid artery (ICA) stenosis by direct observation using a 2 MHz PMD/SGDSA device. PMD identified the artery (location, depth, flow direction) and SGDSA assessed waveform; peak systolic, end diastolic, and mean flow velocities (MFV) of the common carotid artery; cervical ICA proximally and distally; and external carotid artery. Diagnostic accuracy was compared with concurrent carotid duplex ultrasound. The continuity principle was applied using the proximal/distal cervical ICA MFV ratio. We examined 456 vessels (228 patients). Using ICA proximally/ICA distally MFV ratio of 1.5 or greater or absence of ICA signature, for 40% to 59% or greater stenosis (including occlusions), sensitivity was 75.4%, specificity 99.8%, positive predictive value 97.7%, negative predictive value 96.6%, and accuracy 96.7%. For MFV ratio 1.6 or greater or absence of ICA signature and 60% to 79% or greater stenosis (including occlusions), sensitivity was 92.3%, specificity 98.1%, positive predictive value 81.8%, negative predictive value 99.3%, and accuracy 97.6%. Use of combined PMD and SGDSA to directly observe the extracranial ICA is reasonably accurate compared with carotid duplex ultrasound. Using the MFV ratio of proximal/distal extracranial ICA improves accuracy parameters and provides a quick and effective bedside screen for ICA stenosis. This novel technique should be considered part of the standard PMD/transcranial Doppler examination.

  20. Application of contrast-enhanced ultrasound before inferior vena cava filter recovery.

    PubMed

    Yan, Ji-Ping; Li, Wei-Qin; Wang, Zhen-Feng; Guo, Bian-Lian

    2017-10-01

    This study aims to investigate the clinical value of contrast-enhanced ultrasound (CEU) before temporary inferior vena cava filter (IVCF) recovery in patients with deep venous thrombosis, in order to provide ultrasound signs for the recovery of IVCF in clinical practice. The CEU manifestations of patients with deep vein thrombosis before temporary IVCF recovery were retrospectively analyzed. With the manifestations of digital subtraction angiography (DSA) or results of the surgical recovery of IVCF as the standard, the detection rate of a thrombus in IVCF was compared between conventional ultrasound and CEU, and the role of CEU in detecting complications of IVCF was analyzed. In the 103 patients with IVCF, conventional ultrasound and CEU did not reveal any filter displacement and deformation, as well as infection. In 86 patients, filters were successfully recovered under DSA. In one patient, the filter was removed surgically. In 16 patients, recovery failed or was given up, and inferior vena cava (IVC) angiography was performed. The recovery rate of IVCF was 84.5%. Among all cases, thrombi were found within the filters or around the filter in 23 patients. The detection rate of thrombi was 47.8% (11/23) by conventional ultrasound and 82.6% (19/23) by CEU, and the difference between these two methods was statistically significant (P<0.05). CEU drew a misdiagnosis of thrombus within the filter in one patient, and the diagnosis was not confirmed after the recovery of the filter. The diagnostic coincidence rate of CEU for thrombus in the IVCF was 95.1%, and the positive predictive value was 95%. In another case, the foot of the IVCF pierced out of the wall of the IVC into the intestinal wall; and this was confirmed by DSA. Hence, recovery was given up. Thrombosis is the main complication after IVCF placement. CEU revealed typical manifestations of thrombi in the IVC, and has overcome the shortcoming of color Doppler ultrasound such as angular dependence. Its detection

  1. Combined Contrast-Enhanced MRI and Fluorescence Molecular Tomography for Breast Tumor Imaging

    DTIC Science & Technology

    2007-03-01

    accomplishments follows. Imaging system 4 The fluorescence imaging system is coupled into a Philips 3T MRI and is shown schematically in Fig. 1, which...AD_________________ Award Number: W81XWH-06-1-0367 TITLE: Combined Contrast-Enhanced MRI and...CONTRACT NUMBER Combined Contrast-Enhanced MRI and Fluorescence Molecular Tomography for Breast Tumor Imaging 5b. GRANT NUMBER W81XWH-06-1-0367 5c

  2. Emerging role of contrast-enhanced MRI in diagnosing vascular malformations.

    PubMed

    Turley, Ryan S; Lidsky, Michael E; Markovic, Jovan N; Shortell, Cynthia K

    2014-07-01

    Vascular malformations comprise a diverse and rare group of lesions which generally pose a formidable treatment challenge. Requisite for optimal surgical planning are imaging modalities capable of delineating involved anatomy and malformation flow characteristics. In this regard, we and others have purported the advantages of contrast-enhanced MRI. Here, we review the current body of literature regarding the emerging of role of contrast enhanced MRI for the management of vascular malformations.

  3. Breast contrast-enhanced ultrasound: is a scoring system feasible? A preliminary study in China.

    PubMed

    Xiao, Xiaoyun; Ou, Bing; Yang, Haiyun; Wu, Huan; Luo, Baoming

    2014-01-01

    Although many studies about breast contrast-enhanced ultrasound had been conducted, clear diagnostic criteria for evaluating enhancement patterns are still lacking. This study aims to identify significant indicators for breast contrast-enhanced ultrasound and to establish an initial scoring system. Totally 839 patients were included in the study. This study was divided into two parts. 364 patients were included in part 1 while 475 in part 2. Conventional ultrasound and contrast-enhanced ultrasound were used to examine each lesion. Only the cases in part 2 were also examined by elastography. In part 1, Logistic regression analysis was performed to predict significant variables. A 5-point scoring system was developed based on the results. In part 2, the scoring system was used to evaluate all the breast lesions. To evaluate the diagnostic efficacy of the new scoring system, it was compared with the system established for elastography and conventional ultrasound (BI-RADS). Three independent variables, namely, lesion scope, margin, and shape were selected in the final step of the logistic regression analysis in part 1. In part 2, the area under the ROC (receiver operating characteristic) curve for the contrast-enhanced scoring system was 0.912. The difference in the diagnostic capabilities of the contrast-enhanced scoring system and elastography was not statistically significant (P = 0.17). The difference in the diagnostic capabilities of the contrast-enhanced scoring system and BI-RADS was statistically significant (P<0.001). The contrast-enhanced patterns of benign and malignant breast tumors are different. The application of a 5-point scoring system for contrast-enhanced ultrasound is clinically promising.

  4. Breast Contrast-Enhanced Ultrasound: Is a Scoring System Feasible? ----A Preliminary Study in China

    PubMed Central

    Xiao, Xiaoyun; Ou, Bing; Yang, Haiyun; Wu, Huan; Luo, Baoming

    2014-01-01

    Objectives Although many studies about breast contrast-enhanced ultrasound had been conducted, clear diagnostic criteria for evaluating enhancement patterns are still lacking. This study aims to identify significant indicators for breast contrast-enhanced ultrasound and to establish an initial scoring system. Materials and Methods Totally 839 patients were included in the study. This study was divided into two parts. 364 patients were included in part 1 while 475 in part 2. Conventional ultrasound and contrast-enhanced ultrasound were used to examine each lesion. Only the cases in part 2 were also examined by elastography. In part 1, Logistic regression analysis was performed to predict significant variables. A 5-point scoring system was developed based on the results. In part 2, the scoring system was used to evaluate all the breast lesions. To evaluate the diagnostic efficacy of the new scoring system, it was compared with the system established for elastography and conventional ultrasound (BI-RADS). Results Three independent variables, namely, lesion scope, margin, and shape were selected in the final step of the logistic regression analysis in part 1. In part 2, the area under the ROC (receiver operating characteristic) curve for the contrast-enhanced scoring system was 0.912. The difference in the diagnostic capabilities of the contrast-enhanced scoring system and elastography was not statistically significant (P = 0.17). The difference in the diagnostic capabilities of the contrast-enhanced scoring system and BI-RADS was statistically significant (P<0.001). Conclusions The contrast-enhanced patterns of benign and malignant breast tumors are different. The application of a 5-point scoring system for contrast-enhanced ultrasound is clinically promising. PMID:25133534

  5. Intracranial collateral pathways assessed by contrast-enhanced three-dimensional transcranial color-coded sonography.

    PubMed

    Wessels, Tiemo; Bozzato, Alessandro; Mull, Michael; Klötzsch, Christof

    2004-11-01

    Individual parameter settings of the duplex machine and limited insonation angles may influence the visualization of small intracranial vessels in 2-D transcranial color-coded sonography. The aim of our study was the morphologic assessment of intracranial collateral pathways (first auditory area celiac artery, A(1)CA; anterior communicating artery, AComA; first parental generation celiac artery P(1)CA; posterior communicating artery, PComA) using 3-D transcranial color-coded duplex sonography (3-D TCCS) and digital subtraction angiography (DSA). A total of 41 patients with large vessel disease and 30 patients who had suffered subarachnoidal hemorrhage (mean age 52 +/- 15 years) were involved. In all patients, angiography was performed within 10 days following 3-D sonography. The patients were investigated with a color-coded duplex system using the power mode. Contrast enhancement was achieved by continuous infusion of a galactose-based echo-enhancer using a perfusor pump. The 3-D system consists of an electromagnet that induces a low-intensity magnetic field near the head of the patient. A magnetic position sensor is attached to the ultrasound (US) probe and transmits the spatial orientation to a personal computer, which also receives the corresponding 2-D images from the video port of the duplex machine. Angiography revealed a "complete" circle of Willis in one third of the patients and, in the remaining patients at least one vessel was hypoplastic or absent. Sufficient temporal bone windows allowed the sonographic investigation of 466 (94%) of 497 expected arterial segments. The comparison of both techniques resulted in a weighted kappa value of 0.56 for the A(1)CA and 0.63 for the AComA. In the posterior circulation kappa values of 0.56 for the P(1)CA and 0.43 for the PComA were calculated. In 50 vessels (10%), 3-D sonography misdiagnosed the diameter of a collateral vessel as normal and angiography revealed hypoplasia or aplasia of this vessel. The main

  6. Monte Carlo simulation of contrast-enhanced whole brain radiotherapy on a CT scanner.

    PubMed

    Schultz, Bernd-Joachim; Wust, Peter; Lüdemann, Lutz; Jost, Gregor; Pietsch, Hubertus

    2011-08-01

    To perform a feasibility study of contrast-enhanced whole brain radiotherapy for treating patients with multiple brain metastasis using a conventional computed tomography (CT) scanner. The treatment dose was optimized to be applied in a single run using a maximum tube power of 5200 kWs at 140 kV. CT scans of a large and a small head were used as reference. Irradiation geometry, shielding, axial beam collimation, radial beam collimation, gantry tilt, and tube current for beam modulation were optimized using a Monte Carlo simulation and a contrast agent concentration of 5 mg/ml iodine in the tumor. The statistical uncertainty of the Monte Carlo simulation was corrected using back convolution. Using a CT tube with a beam collimation of 28.8 mm, a mean tumor dose of 1.76 +/- 0.13 Gy was achieved, while the head bone dose was 2.61 +/- 0.18 Gy with a normal brain dose of 0.98 +/- 0.06 Gy, eye dose of 0.19 +/- 0.05 Gy, and lens dose of 0.15 +/- 0.03 Gy, respectively. Using a CT tube with dose modulation and a beam collimation of 40.0 mm, the mean tumor dose was 2.00 +/- 0.11 Gy with a head bone dose of 1.96 +/- 0.14 Gy, normal brain dose of 1.13 +/- 0.08 Gy, eye dose of 0.21 +/- 0.05 Gy, and lens dose of 0.16 +/- 0.02 Gy, respectively. Thus a standard CT scanner enables an effective tumor dose of 37.0 Gy to be administered in 13 fractions, while exposing healthy brain to an effective dose of 17.2 Gy and head bone to 69.3 Gy. Additional radial collimation implemented in the hardware improves the therapeutic tumor dose by 25.2% in relation to the bone dose. Contrast-enhanced total brain radiotherapy is feasible using a conventional CT tube with optimized dose application.

  7. Contrast-enhanced optical coherence tomography with picomolar sensitivity for functional in vivo imaging

    NASA Astrophysics Data System (ADS)

    Liba, Orly; Sorelle, Elliott D.; Sen, Debasish; de La Zerda, Adam

    2016-03-01

    Optical Coherence Tomography (OCT) enables real-time imaging of living tissues at cell-scale resolution over millimeters in three dimensions. Despite these advantages, functional biological studies with OCT have been limited by a lack of exogenous contrast agents that can be distinguished from tissue. Here we report an approach to functional OCT imaging that implements custom algorithms to spectrally identify unique contrast agents: large gold nanorods (LGNRs). LGNRs exhibit 110-fold greater spectral signal per particle than conventional GNRs, which enables detection of individual LGNRs in water and concentrations as low as 250 pM in the circulation of living mice. This translates to ~40 particles per imaging voxel in vivo. Unlike previous implementations of OCT spectral detection, the methods described herein adaptively compensate for depth and processing artifacts on a per sample basis. Collectively, these methods enable high-quality noninvasive contrast-enhanced imaging of OCT in living subjects, including detection of tumor microvasculature at twice the depth achievable with conventional OCT. Additionally, multiplexed detection of spectrally-distinct LGNRs was demonstrated to observe discrete patterns of lymphatic drainage and identify individual lymphangions and lymphatic valve functional states. These capabilities provide a powerful platform for molecular imaging and characterization of tissue noninvasively at cellular resolution, called MOZART.

  8. Quantitative contrast-enhanced ultrasound imaging: a review of sources of variability

    PubMed Central

    Tang, M.-X.; Mulvana, H.; Gauthier, T.; Lim, A. K. P.; Cosgrove, D. O.; Eckersley, R. J.; Stride, E.

    2011-01-01

    Ultrasound provides a valuable tool for medical diagnosis offering real-time imaging with excellent spatial resolution and low cost. The advent of microbubble contrast agents has provided the additional ability to obtain essential quantitative information relating to tissue vascularity, tissue perfusion and even endothelial wall function. This technique has shown great promise for diagnosis and monitoring in a wide range of clinical conditions such as cardiovascular diseases and cancer, with considerable potential benefits in terms of patient care. A key challenge of this technique, however, is the existence of significant variations in the imaging results, and the lack of understanding regarding their origin. The aim of this paper is to review the potential sources of variability in the quantification of tissue perfusion based on microbubble contrast-enhanced ultrasound images. These are divided into the following three categories: (i) factors relating to the scanner setting, which include transmission power, transmission focal depth, dynamic range, signal gain and transmission frequency, (ii) factors relating to the patient, which include body physical differences, physiological interaction of body with bubbles, propagation and attenuation through tissue, and tissue motion, and (iii) factors relating to the microbubbles, which include the type of bubbles and their stability, preparation and injection and dosage. It has been shown that the factors in all the three categories can significantly affect the imaging results and contribute to the variations observed. How these factors influence quantitative imaging is explained and possible methods for reducing such variations are discussed. PMID:22866229

  9. Contrast-enhanced optical coherence tomography with picomolar sensitivity for functional in vivo imaging

    PubMed Central

    Liba, Orly; SoRelle, Elliott D.; Sen, Debasish; de la Zerda, Adam

    2016-01-01

    Optical Coherence Tomography (OCT) enables real-time imaging of living tissues at cell-scale resolution over millimeters in three dimensions. Despite these advantages, functional biological studies with OCT have been limited by a lack of exogenous contrast agents that can be distinguished from tissue. Here we report an approach to functional OCT imaging that implements custom algorithms to spectrally identify unique contrast agents: large gold nanorods (LGNRs). LGNRs exhibit 110-fold greater spectral signal per particle than conventional GNRs, which enables detection of individual LGNRs in water and concentrations as low as 250 pM in the circulation of living mice. This translates to ~40 particles per imaging voxel in vivo. Unlike previous implementations of OCT spectral detection, the methods described herein adaptively compensate for depth and processing artifacts on a per sample basis. Collectively, these methods enable high-quality noninvasive contrast-enhanced imaging of OCT in living subjects, including detection of tumor microvasculature at twice the depth achievable with conventional OCT. Additionally, multiplexed detection of spectrally-distinct LGNRs was demonstrated to observe discrete patterns of lymphatic drainage and identify individual lymphangions and lymphatic valve functional states. These capabilities provide a powerful platform for molecular imaging and characterization of tissue noninvasively at cellular resolution, called MOZART. PMID:26987475

  10. Experimental quantification of lesion detectability in contrast enhanced dual energy digital breast tomosynthesis

    NASA Astrophysics Data System (ADS)

    Hu, Yue-Houng; Zhao, Wei

    2012-03-01

    Digital breast tomosynthesis (DBT) is a three-dimensional (3D) x-ray imaging modality that has recently been employed to increase lesion conspicuity through the removal of overlying tissue. Recently, a great deal of work has been devoted to the development of contrast enhanced (CE) DBT. Radio-opaque contrast agents (e.g. iodine) are injected into patients with suspicious breast lesions, with the goal of differentiating malignant tumors from benign by imaging the contrast uptake signature associated with angiogenesis. Either temporal subtraction (TS) or dual energy (DE) subtraction may be performed to further remove structural noise from the images. The current work quantifies the change in power-law noise after either DE subtraction or TS using structured breast tissue equivalent phantoms. Additionally, iodine contrast filled phantoms were used to determine the effect of x-ray energy and image subtraction technique on the signaldifference- to-noise ratio (SDNR). Finally, we investigate the improvement in imaging performance of an amorphous selenium (a-Se) direct conversion flat panel detector with increased a-Se thickness.

  11. Dose and image quality measurements for contrast-enhanced dual energy mammography systems

    NASA Astrophysics Data System (ADS)

    Oduko, J. M.; Homolka, P.; Jones, V.; Whitwam, D.

    2015-03-01

    The results of patient dose surveys of two contrast-enhanced dual energy mammography systems are presented, showing mean glandular doses for both low and high energy components of the exposures. For one system the distribution of doses is of an unusual pattern, very different from that normally measured in patient dose surveys. The contribution of the high energy component of the exposure to the total is shown to be about 20% of that of the low energy component for this system. It is about 33% for the other system, for which the distribution of doses is similar to previously published surveys . A phantom containing disks with a range of different iodine content was used, with tissue-equivalent materials, to investigate the properties of one dual energy system. The iodine signal difference to noise ratio is suggested as a measure of image quality. It was found to remain practically constant as phantom thickness was varied, and increased only slowly (with a power relationship) as air kerma increased. Other measurements showed good reproducibility of the iodine signal difference, and that it was proportional to iodine concentration in the phantom. The iodine signal difference was found to be practically the same for a wide range of phantom thickness and glandularity.

  12. Role of contrast-enhanced harmonic endoscopic ultrasound in submucosal tumors

    PubMed Central

    Alvarez-Sanchez, Maria Victoria; Gincul, Rodica; Lefort, Christine; Napoleon, Bertrand

    2016-01-01

    With the widespread use of endoscopy, gastrointestinal submucosal lesions are now more commonly discovered. Although endoscopic ultrasound (EUS) is superior to all other imaging techniques for the diagnosis of submucosal tumors (SMTs), it is still suboptimal for differentiating hypoechoic lesions arising from the fourth sonographic gastrointestinal wall layer, which encompass tumors with very different prognosis. EUS tissue acquisition has provided with the unique opportunity to obtain histological confirmation, but it is not accurate enough to evaluate the malignant potential of gastrointestinal stromal tumors (GISTs). In the last years, contrast-enhanced harmonic EUS (CH-EUS) emerged as a powerful imaging modality to assess the microperfusion patterns of pancreatic tumors. Based on the distinct microvascularity of malignant SMTs, it was hypothesized that CH-EUS might also assist in the differential diagnosis of SMTs. Preliminary experience in this field is now available and suggests CH-EUS as a performant modality to distinguish between benign SMTs and GISTs and to evaluate the malignant potential of GISTs. High expectations are also relied on CH-EUS for the monitoring of antiangiogenic treatments of GISTs and the evaluation of gastrointestinal neuroendocrine tumors (NETs). PMID:28000626

  13. Role of contrast-enhanced harmonic endoscopic ultrasound in submucosal tumors.

    PubMed

    Alvarez-Sanchez, Maria Victoria; Gincul, Rodica; Lefort, Christine; Napoleon, Bertrand

    2016-01-01

    With the widespread use of endoscopy, gastrointestinal submucosal lesions are now more commonly discovered. Although endoscopic ultrasound (EUS) is superior to all other imaging techniques for the diagnosis of submucosal tumors (SMTs), it is still suboptimal for differentiating hypoechoic lesions arising from the fourth sonographic gastrointestinal wall layer, which encompass tumors with very different prognosis. EUS tissue acquisition has provided with the unique opportunity to obtain histological confirmation, but it is not accurate enough to evaluate the malignant potential of gastrointestinal stromal tumors (GISTs). In the last years, contrast-enhanced harmonic EUS (CH-EUS) emerged as a powerful imaging modality to assess the microperfusion patterns of pancreatic tumors. Based on the distinct microvascularity of malignant SMTs, it was hypothesized that CH-EUS might also assist in the differential diagnosis of SMTs. Preliminary experience in this field is now available and suggests CH-EUS as a performant modality to distinguish between benign SMTs and GISTs and to evaluate the malignant potential of GISTs. High expectations are also relied on CH-EUS for the monitoring of antiangiogenic treatments of GISTs and the evaluation of gastrointestinal neuroendocrine tumors (NETs).

  14. Dynamic contrast enhancement in widefield microscopy using projector-generated illumination patterns

    NASA Astrophysics Data System (ADS)

    Carlo Samson, Edward; Mar Blanca, Carlo

    2007-10-01

    We present a simple and cost-effective optical protocol to realize contrast-enhancement imaging (such as dark-field, optical-staining and oblique illumination microscopy) of transparent samples on a conventional widefield microscope using commercial multimedia projectors. The projector functions as both light source and mask generator implemented by creating slideshows of the filters projected along the illumination planes of the microscope. The projected optical masks spatially modulate the distribution of the incident light to selectively enhance structures within the sample according to spatial frequency thereby increasing the image contrast of translucent biological specimens. Any amplitude filter can be customized and dynamically controlled so that switching from one imaging modality to another involves a simple slide transition and can be executed at a keystroke with no physical filters and no moving optical parts. The method yields an image contrast of 89 96% comparable with standard enhancement techniques. The polarization properties of the projector are then utilized to discriminate birefringent and non-birefringent sites on the sample using single-shot, simultaneous polarization and optical-staining microscopy. In addition to dynamic pattern generation and polarization, the projector also provides high illumination power and spectral excitation selectivity through its red-green-blue (RGB) channels. We exploit this last property to explore the feasibility of using video projectors to selectively excite stained samples and perform fluorescence imaging in tandem with reflectance and polarization reflectance microscopy.

  15. Doppler and the Doppler Effect.

    DTIC Science & Technology

    1984-06-01

    Doppler Applications Doppler Effect Roemer Doppler Principle Bradley Relative motion Velocity History Light Velocity 20. ABSTRACT (Continue on reverse...of Colorado, Boulder, CO 11-14 Jan 1984 5 1. Historical Background The astronomer Olaf Roemer determined the velocity of light in 1676 from time...approached Jupiter and longer when it receded from Jupiter. In effect, Roemer used a Doppler method in determining the velocity of light . [2 ] In 1727

  16. A new hardware-efficient algorithm and reconfigurable architecture for image contrast enhancement.

    PubMed

    Huang, Shih-Chia; Chen, Wen-Chieh

    2014-10-01

    Contrast enhancement is crucial when generating high quality images for image processing applications, such as digital image or video photography, liquid crystal display processing, and medical image analysis. In order to achieve real-time performance for high-definition video applications, it is necessary to design efficient contrast enhancement hardware architecture to meet the needs of real-time processing. In this paper, we propose a novel hardware-oriented contrast enhancement algorithm which can be implemented effectively for hardware design. In order to be considered for hardware implementation, approximation techniques are proposed to reduce these complex computations during performance of the contrast enhancement algorithm. The proposed hardware-oriented contrast enhancement algorithm achieves good image quality by measuring the results of qualitative and quantitative analyzes. To decrease hardware cost and improve hardware utilization for real-time performance, a reduction in circuit area is proposed through use of parameter-controlled reconfigurable architecture. The experiment results show that the proposed hardware-oriented contrast enhancement algorithm can provide an average frame rate of 48.23 frames/s at high definition resolution 1920 × 1080.

  17. Clustered breast microcalcifications: Evaluation by dynamic contrast-enhanced subtraction MRI

    SciTech Connect

    Gilles, R.; Tardivon, A.A.; Vanel, D.; Guinebretiere, J.M.; Arriagada, R.

    1996-01-01

    Our goal was to evaluate dynamic contrast-enhanced subtraction MRI in the diagnosis of isolated clustered calcifications of the breast. One hundred seventy-two patients underwent surgical biopsy for isolated clustered breast calcifications. Their mammograms showed round (n = 88) or linear/irregular (n = 84) microcalcifications. All patients had a preoperative Gd-DOTA-enhanced subtraction dynamic study. Any early contrast enhancement in the breast parenchyma concomitant with early enhancement of normal vessels was considered positive. Fifty-eight in situ carcinomas, 22 invasive carcinomas, and 92 benign lesions were found at histological analysis. Dynamic MR sequences showed early contrast enhancement in 76 of 80 malignant lesions (sensitivity 95%) and in 45 of 92 benign lesions (specificity 51%). Two invasive and two intraductal carcinomas did not show early contrast enhancement. Three independent observers agreed in rating early contrast enhancement in 143 of 172 lesions. Poor specificity limits the diagnostic accuracy of dynamic contrast-enhanced subtraction MRI in distinguishing benign from malignant microcalcifications on mammography. 8 refs., 2 figs., 2 tabs.

  18. Usefulness of enhanced power Doppler imaging in monitoring acral microcirculation in type 2 diabetes mellitus and its complications.

    PubMed

    Ma, Fang; Zhao, Baozhen; Zhang, Huiping; Li, Wei-Ping; Liu, Yuan-Yuan; Dang, Yuan-Yuan; Wu, Rong; Guo, Le Hang; Lu, Chen

    2011-11-01

    This study compared hemodynamic changes of acral arterioles (pulps and nail beds of fingers and toes) and the microcirculatory status of acra between patients with uncomplicated (n = 45) or complicated (n = 36) type 2 diabetic mellitus (type 2 DM) and healthy subjects (n = 40). Enhanced power Doppler imaging (e-Flow) was used to display the nail bed arterioles and distal branches of pulp arterioles (digitales palmares propriea and digitales plantares propriea) in the end knuckle of the right middle finger and right big toe. Arteriolar density (AD) was assessed by vascular pixel percentage. Compared to healthy subjects, in patients with DM the end diastolic velocity (EDV) of the nail bed arterioles of both finger and toe was diminished, while the vascular resistance index (RI) was increased. These changes became more prominent with a longer duration of the disease. Furthermore, both the peak systolic velocity (PSV) and AD were decreased in patients with DM. These hemodynamic changes were also evident in the pulp arterioles of fingers and toes, although they appeared at more advanced stages of the disease. Overall, the abnormal changes were more pronounced in patients with complications. In conclusion, hemodynamic changes (e.g. decrease in the number of acral arterioles) progress with a longer duration of the disease. The acral arteriolar damage is more pronounced in patients with a complicated type 2 DM.

  19. Detection of Leptomeningeal Metastasis by Contrast-Enhanced 3D T1-SPACE: Comparison with 2D FLAIR and Contrast-Enhanced 2D T1-Weighted Images

    PubMed Central

    Gil, Bomi; Hwang, Eo-Jin; Lee, Song; Jang, Jinhee; Jung, So-Lyung; Ahn, Kook-Jin; Kim, Bum-soo

    2016-01-01

    Introduction To compare the diagnostic accuracy of contrast-enhanced 3D(dimensional) T1-weighted sampling perfection with application-optimized contrasts by using different flip angle evolutions (T1-SPACE), 2D fluid attenuated inversion recovery (FLAIR) images and 2D contrast-enhanced T1-weighted image in detection of leptomeningeal metastasis except for invasive procedures such as a CSF tapping. Materials and Methods Three groups of patients were included retrospectively for 9 months (from 2013-04-01 to 2013-12-31). Group 1 patients with positive malignant cells in CSF cytology (n = 22); group 2, stroke patients with steno-occlusion in ICA or MCA (n = 16); and group 3, patients with negative results on MRI, whose symptom were dizziness or headache (n = 25). A total of 63 sets of MR images are separately collected and randomly arranged: (1) CE 3D T1-SPACE; (2) 2D FLAIR; and (3) CE T1-GRE using a 3-Tesla MR system. A faculty neuroradiologist with 8-year-experience and another 2nd grade trainee in radiology reviewed each MR image- blinded by the results of CSF cytology and coded their observations as positives or negatives of leptomeningeal metastasis. The CSF cytology result was considered as a gold standard. Sensitivity and specificity of each MR images were calculated. Diagnostic accuracy was compared using a McNemar’s test. A Cohen's kappa analysis was performed to assess inter-observer agreements. Results Diagnostic accuracy was not different between 3D T1-SPACE and CSF cytology by both raters. However, the accuracy test of 2D FLAIR and 2D contrast-enhanced T1-weighted GRE was inconsistent by the two raters. The Kappa statistic results were 0.657 (3D T1-SPACE), 0.420 (2D FLAIR), and 0.160 (2D contrast-enhanced T1-weighted GRE). The 3D T1-SPACE images showed the highest inter-observer agreements between the raters. Conclusions Compared to 2D FLAIR and 2D contrast-enhanced T1-weighted GRE, contrast-enhanced 3D T1 SPACE showed a better detection rate of

  20. Contrast-enhanced MR angiography of cavopulmonary connections in adult patients with congenital heart disease.

    PubMed

    Wagner, Moritz; Nguyen, Kim-Lien; Khan, Sarah; Mirsadraee, Saeed; Satou, Gary M; Aboulhosn, Jamil; Finn, J Paul

    2012-11-01

    The purpose of this study is to evaluate combined time-resolved and high-spatial resolution contrast-enhanced MR angiography (MRA) for assessment of cavopulmonary connections in adult patients with congenital heart disease. Twenty-eight adults with various surgical cavopulmonary connections (Glenn shunt and Fontan connection) underwent high-spatial-resolution contrast-enhanced MRA (voxel size, 1.95 mm(3); temporal resolution, 22 seconds) and time-resolved contrast-enhanced MRA (voxel size, 6.5-9.3 mm(3); temporal resolution, < 1.2 seconds). Ten patients had 2D phase contrast flow quantification measurements performed at the same setting. Two readers independently assessed anatomic dimensions of cavopulmonary connections (using high-spatial-resolution contrast-enhanced MRA) and pulmonary artery (PA) perfusion patterns (using time-resolved contrast-enhanced MRA). High-spatial-resolution contrast-enhanced MRA yielded diagnostic-quality images for morphologic assessment of cavopulmonary connections in 27 of 28 (96%) patients. The anatomic dimensions (cross-sectional area) of the PA and cavopulmonary connections showed a wide variation (right PA, 0.99-5.67 cm(2); left PA, 0.80-5.69 cm(2); Glenn shunt, 0.93-6.94 cm(2); and Fontan connection, 1.25-6.67 cm(2)). The anatomic dimensions could be assessed with excellent interobserver agreement on high-spatial-resolution contrast-enhanced MRA (r = 0.895). Time-resolved contrast-enhanced MRA yielded diagnostic-quality images in all patients and enabled characterization of PA perfusion via the superior vena cava as follows: preferential inflow to the right PA (n = 12), preferential inflow to the left PA (n = 5), and balanced inflow to the right and left PA (n = 11). In those patients who had technically successful flow quantification measurements, phase contrast data confirmed patency of the cavopulmonary connections. Combined time-resolved contrast-enhanced MRA and high-spatial-resolution contrast-enhanced MRA allowed detailed

  1. Feasibility of Antegrade Contrast-enhanced US Nephrostograms to Evaluate Ureteral Patency.

    PubMed

    Chi, Thomas; Usawachintachit, Manint; Mongan, John; Kohi, Maureen P; Taylor, Andrew; Jha, Priyanka; Chang, Helena C; Stoller, Marshall; Goldstein, Ruth; Weinstein, Stefanie

    2017-04-01

    Purpose To demonstrate the feasibility of contrast material-enhanced ulrasonographic (US) nephrostograms to assess ureteral patency after percutaneous nephrolithotomy (PCNL) in this proof-of-concept study. Materials and Methods For this HIPAA-compliant, institutional review board-approved prospective blinded pilot study, patients undergoing PCNL provided consent to undergo contrast-enhanced US and fluoroscopic nephrostograms on postoperative day 1. For contrast-enhanced US, 1.5 mL of Optison (GE Healthcare, Oslo, Norway) microbubble contrast agent solution (perflutren protein-type A microspheres) was injected via the nephrostomy tube. Unobstructed antegrade ureteral flow was defined by the presence of contrast material in the bladder. Contrast-enhanced US results were compared against those of fluoroscopic nephrostograms for concordance. Results Ten studies were performed in nine patients (four women, five men). Contrast-enhanced US demonstrated ureteral patency in eight studies and obstruction in two. One patient underwent two studies, one showing obstruction and the second showing patency. Concordance between US and fluoroscopic assessments of ureteral patency was evaluated by using a Clopper-Pearson exact binomial test. These results were perfectly concordant with fluoroscopic nephrostogram results, with a 95% confidence interval of 69.2% and 100%. No complications or adverse events related to contrast-enhanced US occurred. Conclusion Contrast-enhanced US nephrostograms are simple to perform and are capable of demonstrating both patency and obstruction of the ureter. The perfect concordance with fluoroscopic results across 10 studies demonstrated here is not sufficient to establish diagnostic accuracy of this technique, but motivates further, larger scale investigation. If subsequent larger studies confirm these preliminary results, contrast-enhanced US may provide a safer, more convenient way to evaluate ureteral patency than fluoroscopy. (©) RSNA, 2016 Online

  2. Three-dimensional ultrasonography and power Doppler for discrimination between benign and malignant endometrium in premenopausal women with abnormal uterine bleeding.

    PubMed

    El-Sharkawy, Mohamed; El-Mazny, Akmal; Ramadan, Wafaa; Hatem, Dina; Abdel-Hafiz, Aly; Hammam, Mohamed; Nada, Adel

    2016-03-16

    Ultrasonography has been extensively used in women suspected of having a gynecological malignancy. The aim of this study is to evaluate the efficacy of 3D ultrasonography and power Doppler for discrimination between benign and malignant endometrium in premenopausal women with abnormal uterine bleeding. This cross-sectional study included 78 premenopausal women with abnormal uterine bleeding scheduled for hysteroscopy and endometrial curettage. The endometrial thickness (ET), uterine artery pulsatility index (PI) and resistance index (RI), and endometrial volume (EV) and 3D power Doppler vascularization index (VI), flow index (FI), and vascularization flow index (VFI) were measured and compared with hysteroscopic and histopathologic findings. The ET (P <0.001), EV (P <0.001), and endometrial VI (P <0.001) and VFI (P = 0.043) were significantly increased in patients with atypical endometrial hyperplasia and endometrial carcinoma (n = 10) than those with benign endometrium (n = 68); whereas, the uterine artery PI and RI and endometrial FI were not significantly different between the two groups. The best marker for discrimination between benign and malignant endometrium was the VI with an area under the ROC curve of 0.88 at a cutoff value of 0.81%. 3D ultrasonography and power Doppler, especially endometrial VI, may be useful for discrimination between benign and malignant endometrium in premenopausal women with abnormal uterine bleeding.

  3. Internal carotid artery stenosis: accuracy of subjective visual impression for evaluation with digital subtraction angiography and contrast-enhanced MR angiography.

    PubMed

    U-King-Im, Jean Marie; Graves, Martin J; Cross, Justin J; Higgins, Nicholas J; Wat, Josephine; Trivedi, Rikin A; Tang, Tjun; Howarth, Simon P S; Kirkpatrick, Peter J; Antoun, Nagui M; Gillard, Jonathan H

    2007-07-01

    To prospectively determine, for both digital subtraction angiography (DSA) and contrast material-enhanced magnetic resonance (MR) angiography, the accuracy of subjective visual impression (SVI) in the evaluation of internal carotid artery (ICA) stenosis, with objective caliper measurements serving as the reference standard. Local ethics committee approval and written informed patient consent were obtained. A total of 142 symptomatic patients (41 women, 101 men; mean age, 70 years; age range, 44-89 years) suspected of having ICA stenosis on the basis of Doppler ultrasonographic findings underwent both DSA and contrast-enhanced MR angiography. With each modality, three independent neuroradiologists who were blinded to other test results first visually estimated and subsequently objectively measured stenoses. Diagnostic accuracy and percentage misclassification for correct categorization of 70%-99% stenosis were calculated for SVI, with objective measurements serving as the reference standard. Interobserver variability was determined with kappa statistics. After exclusion of arteries that were unsuitable for measurement, 180 vessels remained for analysis with DSA and 159 vessels remained for analysis with contrast-enhanced MR angiography. With respect to 70%-99% stenosis, SVI was associated with average misclassification of 8.9% for DSA (8.9%, 7.8%, and 10.0% for readers A, B, and C, respectively) and of 11.7% for contrast-enhanced MR angiography (11.3%, 8.8%, and 15.1% for readers A, B, and C, respectively). Negative predictive values were excellent (92.3%-100%). Interobserver variability was higher for SVI (DSA, kappa = 0.62-0.71; contrast-enhanced MR angiography, kappa = 0.57-0.69) than for objective measurements (DSA, kappa = 0.75-0.80; contrast-enhanced MR angiography, kappa = 0.66-0.72). SVI alone is not recommended for evaluation of ICA stenosis with both DSA and contrast-enhanced MR angiography. SVI may be acceptable as an initial screening tool to exclude the

  4. An improved coverage and spatial resolution--using dual injection dynamic contrast-enhanced (ICE-DICE) MRI: a novel dynamic contrast-enhanced technique for cerebral tumors.

    PubMed

    Li, Ka-Loh; Buonaccorsi, Giovanni; Thompson, Gerard; Cain, John R; Watkins, Amy; Russell, David; Qureshi, Salman; Evans, D Gareth; Lloyd, Simon K; Zhu, Xiaoping; Jackson, Alan

    2012-08-01

    A new dual temporal resolution-based, high spatial resolution, pharmacokinetic parametric mapping method is described--improved coverage and spatial resolution using dual injection dynamic contrast-enhanced (ICE-DICE) MRI. In a dual-bolus dynamic contrast-enhanced-MRI acquisition protocol, a high temporal resolution prebolus is followed by a high spatial resolution main bolus to allow high spatial resolution parametric mapping for cerebral tumors. The measured plasma concentration curves from the dual-bolus data were used to reconstruct a high temporal resolution arterial input function. The new method reduces errors resulting from uncertainty in the temporal alignment of the arterial input function, tissue response function, and sampling grid. The technique provides high spatial resolution 3D pharmacokinetic maps (voxel size 1.0 × 1.0 × 2.0 mm(3)) with whole brain coverage and greater parameter accuracy than that was possible with the conventional single temporal resolution methods. High spatial resolution imaging of brain lesions is highly desirable for small lesions and to support investigation of heterogeneity within pathological tissue and peripheral invasion at the interface between diseased and normal brain. The new method has the potential to be used to improve dynamic contrast-enhanced-MRI techniques in general.

  5. Medical image visual appearance improvement using bihistogram Bezier curve contrast enhancement: data from the Osteoarthritis Initiative.

    PubMed

    Gan, Hong-Seng; Swee, Tan Tian; Abdul Karim, Ahmad Helmy; Sayuti, Khairil Amir; Abdul Kadir, Mohammed Rafiq; Tham, Weng-Kit; Wong, Liang-Xuan; Chaudhary, Kashif T; Ali, Jalil; Yupapin, Preecha P

    2014-01-01

    Well-defined image can assist user to identify region of interest during segmentation. However, complex medical image is usually characterized by poor tissue contrast and low background luminance. The contrast improvement can lift image visual quality, but the fundamental contrast enhancement methods often overlook the sudden jump problem. In this work, the proposed bihistogram Bezier curve contrast enhancement introduces the concept of "adequate contrast enhancement" to overcome sudden jump problem in knee magnetic resonance image. Since every image produces its own intensity distribution, the adequate contrast enhancement checks on the image's maximum intensity distortion and uses intensity discrepancy reduction to generate Bezier transform curve. The proposed method improves tissue contrast and preserves pertinent knee features without compromising natural image appearance. Besides, statistical results from Fisher's Least Significant Difference test and the Duncan test have consistently indicated that the proposed method outperforms fundamental contrast enhancement methods to exalt image visual quality. As the study is limited to relatively small image database, future works will include a larger dataset with osteoarthritic images to assess the clinical effectiveness of the proposed method to facilitate the image inspection.

  6. [Detection and quantification of myocardial fibrosis in hypertrophic cardiomyopathy by contrast-enhanced cardiovascular magnetic resonance].

    PubMed

    Pujadas, Sandra; Carreras, Francesc; Arrastio, Xabier; Leta, Rubén; Vila, Montserrat; Subirana, María Teresa; Bayés-Genís, Antoni; Pons-Lladó, Guillem

    2007-01-01

    Severity of hypertrophic cardiomyopathy has been associated with the amount of myocardial fibrosis in autopsy studies. Cardio-vascular magnetic resonance allows, by means of the delayed contrast-enhancement technique, an in vivo detection of focal myocardial fibrosis. Our aim was to study myocardial fibrosis in patients with hypertrophic cardiomyopathy by means of contrast-enhance cardio-vascular magnetic resonance. 43 patients (30 males; mean age 47 [18] years) were studied by cardio-vascular magnetic resonance. In all patients left ventricular function and mass was analyzed. Total mass of myocardial fibrosis, as identified by delayed contrast-enhancement, was also calculated. In 63% of patients some degree of myocardial delayed contrast-enhancement was observed, total mass of myocardial fibrosis ranging between 1 and 59 g (mean: 17 g). There was a positive correlation between the amount of myocardial fibrosis and the degree of hypertrophy. Maximal wall thickness was higher in patients with myocardial fibrosis (23 [7] vs 18 [4] mm, respectively, P=.04). Familial cases were also more prevalent among this group (48% vs 13%, respectively), as well as conventional clinical risk factors. Myocardial fibrosis as detected by contrast-enhanced cardio-vascular magnetic resonance is highly prevalent in hypertrophic cardiomyopathy patients, particularly in familial cases with severe hypertrophy and associated risk factors.

  7. Determination of contrast media administration to achieve a targeted contrast enhancement in CT

    NASA Astrophysics Data System (ADS)

    Sahbaee, Pooyan; Li, Yuan; Segars, Paul; Marin, Daniele; Nelson, Rendon; Samei, Ehsan

    2015-03-01

    Contrast enhancement is a key component of CT imaging and offer opportunities for optimization. The design and optimization of new techniques however requires orchestration with the scan parameters and further a methodology to relate contrast enhancement and injection function. In this study, we used such a methodology to develop a method, analytical inverse method, to predict the required injection function to achieve a desired contrast enhancement in a given organ by incorporation of a physiologically based compartmental model. The method was evaluated across 32 different target contrast enhancement functions for aorta, kidney, stomach, small intestine, and liver. The results exhibited that the analytical inverse method offers accurate performance with error in the range of 10% deviation between the predicted and desired organ enhancement curves. However, this method is incapable of predicting the injection function based on the liver enhancement. The findings of this study can be useful in optimizing contrast medium injection function as well as the scan timing to provide more consistency in the way that the contrast enhanced CT examinations are performed. To our knowledge, this work is one of the first attempts to predict the contrast material injection function for a desired organ enhancement curve.

  8. Effect of pregestational diabetes mellitus on first trimester placental characteristics: three-dimensional placental volume and power Doppler indices.

    PubMed

    Gonzalez Gonzalez, N L; Gonzalez Davila, E; Castro, A; Padron, E; Plasencia, W

    2014-03-01

    To investigate whether pregestational diabetes mellitus (DM) induces changes in vascular placental development detectable at first trimester. This was a prospective case-control study in 69 women with pregestational DM and 94 controls undergoing first-trimester combined screening for aneuploidies. Maternal characteristics, fetal nuchal translucency thickness, maternal serum pregnancy-associated plasma protein A (PAPP-A) and free β human chorionic gonadotrophin (β-hCG) were evaluated. Three-dimensional ultrasound was used to measure placental volume and three dimensional power Doppler (3D-PD) placental vascular indices including: vascularization index (VI), flow index (FI) and vascularization flow index (VFI). Pregnancy-associated hypertensive complications (PAHC) and perinatal outcomes were analyzed. The total group of diabetic women and the group of diabetic women without PAHC were compared separately with the control group. 3D-PD placental vascular indexes were significantly lower in women with DM than in controls (VI p = 0.007, FI p = 0.003 and VFI p = 0.04). These differences remained on excluding cases with PAHC in the DM group. No differences were found in placental volumes between the DM group and controls. Serum PAPP-A levels were also lower in diabetic women (p < 0.02) and negatively correlated with the degree of maternal metabolic control at first trimester. Pregestational DM induces demonstrable alterations in first trimester placental development, with significantly reduced placental vascularization indices and PAPP-A values. This effect is independent of the later development of PAHC. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. The value of power Doppler ultrasound in patients with rheumatoid arthritis in clinical remission: Reclassifying disease activity?

    PubMed

    Vergara, Facundo; Ruta, Santiago; Rosa, Javier; Marín, Josefina; García-Mónaco, Ricardo; Soriano, Enrique R

    2017-03-18

    The aim of the present study was to describe the ultrasound (US) findings in patients with rheumatoid arthritis (RA) in clinical remission, and to evaluate the ability of power Doppler (PD) US to reclassify disease activity in these patients. We included consecutive patients with RA according to 2010 American College of Rheumatology/European League Against Rheumatism criteria, who were in clinical remission by the Disease Activity Score (DAS28<2.6). Twenty joints of both hands were assessed by US. PD signal was evaluated on a semi-quantitative scale from 0 to 3. Three different US-modified DAS28 (US-DAS28) were constructed, replacing the clinical swollen joint count by the PD US joint count using PD score ≥1, ≥2 or ≥3, respectively. Eighty-six patients were included. Twenty-three (26.7%) patients had at least one joint with abnormal US-positive PD signal. Thirteen percent of patients were reclassified to low disease activity by applying the US-DAS28 when joints were considered active with a PD signal ≥1; 12%, when a PD signal ≥2 was considered, and 2% of the patients were reclassified when a PD score of 3 was considered. No patients were reclassified to a level of moderate or high activity applying US-DAS28. Although around a quarter of patients with RA in clinical remission showed PD US features indicating residual activity, only a small percentage were reclassified to a state of low activity and none to a level of moderate or high activity, applying the proposed US-DAS28. Copyright © 2017 Elsevier España, S.L.U. and Sociedad Española de Reumatología y Colegio Mexicano de Reumatología. All rights reserved.

  10. Power Doppler sonography versus Tc-99m DMSA scintigraphy for diagnosing acute pyelonephritis in children: are these two methods comparable?

    PubMed

    Bykov, Sergey; Chervinsky, Leonid; Smolkin, Vladislav; Halevi, Rafi; Garty, Izak

    2003-03-01

    PURPOSE This study assessed the role of renal power Doppler ultrasonography (PDU) to identify acute pyelonephritis (APN) and to determine whether PDU can replace Tc-99m DMSA renal scintigraphy in the diagnosis of APN in children. METHODS A prospective study was conducted in 40 infants and young children (78 kidneys were evaluated) with a mean age of 25.9 months (range, 1 to 68 months) who were hospitalized with a first episode of high fever and bacteruria, possibly APN. All children were examined by PDU and Tc-99m DMSA within the first 3 days after admission. Patients with congenital abnormalities, hydronephrosis, and urinary reflux were excluded. RESULTS Twenty-seven of the 78 kidneys appeared abnormal on Tc-99m DMSA, and 20 of them were abnormal on PDU. Fifty-one of 78 kidneys were normal on Tc-99m DMSA, and 3 of 51 appeared diseased on PDU. The accuracy of PDU was 87%, sensitivity was 74%, and specificity was 94%. The positive predictive and negative predictive values were both 87%. When considering the numbers of lesions in 27 kidneys with positive Tc-99m DMSA studies (38 lesions), PDU did not disclose 16 lesions (false-negative results). Thus, the sensitivity of PDU for diagnosing lesions of APN decreased to 58%. CONCLUSIONS A positive PDU finding should obviate the use of Tc-99m DMSA in patients thought to have possible APN. However, because of a large number of false-negative results (26%) and underestimation of the number of pyelonephritic lesions (low sensitivity of 58%), PDU cannot replace Tc-99m DMSA in the diagnosis of APN in children.

  11. Haemodynamic Optimization by Oesophageal Doppler and Pulse Power Wave Analysis in Liver Surgery: A Randomised Controlled Trial.

    PubMed

    Feldheiser, Aarne; Pavlova, Velizara; Weimann, Karin; Hunsicker, Oliver; Stockmann, Martin; Koch, Mandy; Giebels, Alexander; Wernecke, Klaus-Dieter; Spies, Claudia D

    2015-01-01

    Liver surgery is still associated with a high rate of morbidity and mortality. We aimed to compare different haemodynamic treatments in liver surgery. In a prospective, blinded, randomised, controlled pilot trial patients undergoing liver resection were randomised to receive haemodynamic management guided by conventional haemodynamic parameters or by oesophageal Doppler monitor (ODM, CardioQ-ODM) or by pulse power wave analysis (PPA, LiDCOrapid) within a goal-directed algorithm adapted for liver surgery. The primary endpoint was stroke volume index before intra-operative start of liver resection. Secondary endpoints were the haemodynamic course during surgery and postoperative pain levels. Due to an unbalance in the extension of the surgical procedures with a high rate of only minor procedures the conventional group was dropped from the analysis. Eleven patients in the ODM group and 10 patients in the PPA group were eligible for statistical analysis. Stroke volume index before start of liver resection was 49 (37; 53) ml/m2 and 48 (41; 56) ml/m2 in the ODM and PPA group, respectively (p=0.397). The ODM guided group was haemodynamically stable as shown by ODM and PPA measurements. However, the PPA guided group showed a significant increase of pulse-pressure-variability (p=0.002) that was not accompanied by a decline of stroke volume index displayed by the PPA (p=0.556) but indicated by a decline of stroke volume index by the ODM (p<0.001). The PPA group had significantly higher postoperative pain levels than the ODM group (p=0.036). In conclusion, goal-directed optimization by ODM and PPA showed differences in intraoperative cardiovascular parameters indicating that haemodynamic optimization is not consistent between the two monitors. ISRCTN.com ISRCTN64578872.

  12. Haemodynamic Optimization by Oesophageal Doppler and Pulse Power Wave Analysis in Liver Surgery: A Randomised Controlled Trial

    PubMed Central

    Feldheiser, Aarne; Pavlova, Velizara; Weimann, Karin; Hunsicker, Oliver; Stockmann, Martin; Koch, Mandy; Giebels, Alexander; Wernecke, Klaus-Dieter; Spies, Claudia D.

    2015-01-01

    Liver surgery is still associated with a high rate of morbidity and mortality. We aimed to compare different haemodynamic treatments in liver surgery. In a prospective, blinded, randomised, controlled pilot trial patients undergoing liver resection were randomised to receive haemodynamic management guided by conventional haemodynamic parameters or by oesophageal Doppler monitor (ODM, CardioQ-ODM) or by pulse power wave analysis (PPA, LiDCOrapid) within a goal-directed algorithm adapted for liver surgery. The primary endpoint was stroke volume index before intra-operative start of liver resection. Secondary endpoints were the haemodynamic course during surgery and postoperative pain levels. Due to an unbalance in the extension of the surgical procedures with a high rate of only minor procedures the conventional group was dropped from the analysis. Eleven patients in the ODM group and 10 patients in the PPA group were eligible for statistical analysis. Stroke volume index before start of liver resection was 49 (37; 53) ml/m2 and 48 (41; 56) ml/m2 in the ODM and PPA group, respectively (p=0.397). The ODM guided group was haemodynamically stable as shown by ODM and PPA measurements. However, the PPA guided group showed a significant increase of pulse-pressure-variability (p=0.002) that was not accompanied by a decline of stroke volume index displayed by the PPA (p=0.556) but indicated by a decline of stroke volume index by the ODM (p<0.001). The PPA group had significantly higher postoperative pain levels than the ODM group (p=0.036). In conclusion, goal-directed optimization by ODM and PPA showed differences in intraoperative cardiovascular parameters indicating that haemodynamic optimization is not consistent between the two monitors. Trial Registration ISRCTN.com ISRCTN64578872 PMID:26186702

  13. Subclinical enthesopathy in patients with psoriasis and its association with other disease parameters: a power Doppler ultrasonographic study

    PubMed Central

    Moshrif, Abdelhafeez; Mosallam, Ahmed; Mohamed, Essam elden M.; Gouda, Wesam; Doma, Mostafa

    2017-01-01

    Objective This study aimed to determine the prevalence of subclinical enthesopathy in patients with psoriasis using power Doppler ultrasonography (PDUS) and its association with other disease parameters. Material and Methods A total of 50 patients with psoriasis (31 females) aged 19–70 years underwent a thorough clinical examination that included assessment of body mass index (BMI) and psoriasis area and severity index (PASI) score. Measurements of inflammatory markers, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), serum uric acid, and plain radiography of the heels, knees, and sacroiliac joints were performed for all patients. Patients without clinical evidence of arthritis or enthesitis underwent an ultrasonographic (US) examination. According to the US examination, patients were classified into group I (patients with enthesitis) and group II (patients without enthesitis). Results In group I, Achilles enthesis was the most common site of US enthesitis (33.3%), followed by distal patellar enthesis (22.2%), proximal patellar enthesis (16.7%), quadriceps enthesis (16.7%), and plantar aponeurosis enthesis (11.1%). There was a statistically significant positive correlation between the occurrence of enthesitis and the patient’s age, disease duration, PASI score, BMI, and hyperuricemia (p<0.05 for each). In contrast, there was no significant correlation between enthesitis and sex or radiographic sacroiliitis (p>0.05 for each). Conclusion In addition to the importance of PDUS as a complimentary tool for examining enthesis in patients with psoriasis, the presence of high PASI score, increased BMI and hyperuricemia, and a long disease duration can be considered as predictive parameters for the presence of psoriatic enthesitis. PMID:28293449

  14. Intrinsic subtypes and tumor grades in breast cancer are associated with distinct 3-D power Doppler sonographic vascular features.

    PubMed

    Chang, Yeun-Chung; Huang, Yao-Sian; Huang, Chiun-Sheng; Chen, Jeon-Hor; Chang, Ruey-Feng

    2014-08-01

    This study aimed to investigate the three-dimensional (3-D) power Doppler ultrasonographic (PDUS) vascular features of breast carcinoma according to intrinsic subtypes, nodal stage, and tumor grade. Total 115 receiving mastectomy breast carcinomas (mean size, 2.5 cm; range, 0.7-6.5 cm), including 102 invasive ductal carcinomas (IDC), 10 ductal carcinomas in situ (DCIS), and 3 invasive lobular carcinomas (ILC) diagnosed after mastectomy, were used in this retrospective study. Sixty IDC had nodal status and histopathologic tumor grades available for analysis. Vascular features, including number of vascular trees (NV), longest path length (LPL), total vessel length (TVL), number of bifurcations (NB), distance metric (DM), inflection count metric (ICM), vessel diameter (VD), and vessel-to-volume ratio (VVR) were extracted using 3-D thinning method. The Mann-Whitney U test, Student's t-test, one-way ANOVA, and Kruskal-Wallis test were performed as appropriate. There was no significant difference of vascular features among IDC, DCIS and ILC. Except VD, vascular features in luminal type were significantly lower compared to HER2-enriched or triple negative types (p<0.05). Compared to ER+ (estrogen receptor positive) tumors, all features in ER- (estrogen receptor negative) tumors were significantly higher (p<0.01). Despite some significantly higher vascular features in high grade IDC compared to low and intermediate grade, there was no significant correlation between vascular features and nodal stages. Differences in 3-D PDUS vascular features among intrinsic types of IDC are attributed to their ER status. Vascular features extracted by 3-D PDUS correlate with tumor grades but not nodal stage in IDC. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  15. Evaluation of solid breast lesions with power Doppler: value of penetrating vessels as a predictor of malignancy

    PubMed Central

    Ibrahim, Rositaa; Rahmat, Kartini; Fadzli, Farhana; Rozalli, Faizatul Izza; Westerhout, Caroline Judy; Alli, Kasumawati; Vijayananthan, Anushya; Moosa, Fatimah

    2016-01-01

    INTRODUCTION This study aimed to evaluate the vascular pattern of solid breast lesions using power Doppler ultrasonography (PDUS) and assess whether the presence of intratumoural penetrating vessels can predict breast cancer malignancy. METHODS Greyscale ultrasonography (US) and PDUS were prospectively performed on 91 women in Malaysia with histopathologically proven breast lesions. The diagnostic accuracy of greyscale US, PDUS, and both greyscale US and PDUS was calculated and compared. RESULTS The 91 women had 102 breast lesions (55 benign, 47 malignant). Of the 47 malignant lesions, 36 demonstrated intratumoural penetrating vessels. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of greyscale US findings in diagnosing malignancy were 100.0%, 71.4%, 74.1% and 100.0%, respectively. The presence of calcification in the breast lesion and the margin, shape and posterior acoustic features of the lesion were significant parameters in predicting malignancy (p < 0.01). The sensitivity, specificity, PPV and NPV of the presence of intratumoural penetrating vessels in predicting malignancy were 76.5%, 80.0%, 76.5% and 80.0%, respectively. When both greyscale US and PDUS were used, there was a significant correlation in predicting malignancy (p < 0.05). The specificity and PPV values of the combined greyscale US and PDUS method (89.0% and 85.7%, respectively) were higher than those of greyscale US or PDUS alone. CONCLUSION Flow patterns revealed by PDUS can be useful for differentiating benign and malignant breast lesions. The visualisation of penetrating vessels in solid breast lesions can be used to complement greyscale US findings in predicting malignancy. PMID:27872938

  16. The relationship of patient-reported joints with active synovitis detected by power Doppler ultrasonography in rheumatoid arthritis.

    PubMed

    Cheung, Peter P; Gossec, Laure; Ruyssen-Witrand, Adeline; Le Bourlout, Catherine; Mézières, Maryse; Dougados, Maxime

    2013-01-01

    This paper aims to evaluate the relationship of patient-reported tender and swollen joints with active inflammation as detected by power Doppler (PDUS) and whether this relationship is affected by significant joint damage. Fifty rheumatoid arthritis patients self-assessed 28 tender and swollen joints and were followed by PDUS assessment. Relationship of tender and swollen joints with active synovitis (PDUS 'gold standard') was assessed at the joint level by: a) percentage agreement at each PDUS semiquantitative grade (grade 1 to 3), b) positive likelihood ratio (LR) of agreement with PDUS, and c) LR of agreement with PDUS according to radiographic damage (significant erosive disease vs. non-erosive disease). Correlation of tender and swollen joint counts with disease activity markers was analysed by Spearman's. Sensitivity analyses examined the influence of disease activity or global pain on level of agreement at the joint level. Of joints with significant active inflammation (e.g. grade 3 PDUS), patients identified 75% as tender and 63% as swollen. Swollen joints showed strong association at the joint level with active synovitis when there was no significant radiographic damage (LR 2.54, 95%CI 1.93-3.34), but with no significant radiographic damage (LR 1.32, 95%CI 0.75-2.32). Swollen joint counts were statistically correlated with PDUS-DAS28 and CRP, but not PDUS score. Sensitivity analysis showed better agreement of tender and swollen joints with active synovitis when DAS28 was ≤ 3.2 and when patient global pain was <50mm on visual analogue scale. The relationship between patient-reported joints and active synovitis is stronger in the setting of low disease activity without erosive disease, affected also by degree of reported global pain. Further longitudinal studies of patient-reported joints are needed.

  17. Hürthle cell neoplasm: correlation of gray-scale and power Doppler sonographic findings with gross pathology.

    PubMed

    Lee, Sang Kwon; Rho, Byung Hak; Woo, Seong-Ku

    2010-05-01

    To describe gray-scale and power Doppler (PD) sonographic (US) findings of Hürthle cell neoplasms (HCNs) of the thyroid gland, and to determine if there is any correlation between US and gross pathologic features. This retrospective study included 30 pathologically proven HCNs in 30 subjects who underwent preoperative gray-scale and PD US examinations. The size, shape, margin, echogenicity, echotexture, presence or absence of cystic change, calcifications and halo sign, and vascularity at PD US were evaluated. The longest diameter of HCNs ranged from 12 mm to 63 mm. The shape and margins of the mass were ovoid and smooth, respectively, in all cases. The echogenicity was hypoechoic, isoechoic, hyperechoic, or mixed in 43.3%, 33.3%, 10.0%, and 13.3%, respectively. The echotexture was heterogeneous in 73.3% and homogeneous in 26.7%. Cystic change was present in 56.7% and involved less than 25% of the volume of the mass in 50.0% and 26-50% of the volume in 6.7%. Coarse calcifications were present in 20.0%. Halo sign was present in all cases. The vascularity was combined peri- and intranodular in all cases: predominantly intranodular in 50.0%, predominantly perinodular in 46.7%, and of the "inferno" type in 3.3%. All HCNs were encapsulated on gross pathologic examination. Although many of the US features we observed were nonspecific, HCNs tend to have a halo sign and combined peri- and intranodular vascularity on US, which raises the possibility of an association. The US halo sign corresponds to tumor capsule ongross pathologic examination.

  18. Contrast-enhanced ultrasonography in the diagnosis of upper urinary tract urothelial cell carcinoma: a preliminary study.

    PubMed

    Drudi, F M; Di Candio, G; Di Leo, N; Malpassini, F; Gnecchi, M; Cantisani, V; Iori, F; Liberatore, M

    2013-02-01

    The main objective was to assess the effectiveness of contrast-enhanced ultrasonography (CEUS) in the diagnosis of upper urinary tract malignancies by comparing with multidetector computed tomographic urography (MDCTU) and magnetic resonance urography (MRU). Secondary objectives were to compare the tumor size measured with CEUS, MDCTU and MRU and to assess the usefulness of CEUS in distinguishing high-grade tumors from low-grade ones. In connection with this prospective study carried out from January 2009 to September 2011, 18 patients underwent MDCTU or MRU, grayscale ultrasonography (US), color Doppler ultrasonography and CEUS followed by surgery and histological examination of the specimen. Quantitative analysis was performed using perfusion software. Time intensity curves were extracted and the following parameters were considered: wash-in time, time-to-peak, maximum signal intensity and wash-out time. Grayscale US identified 15/18 lesions; color Doppler showed no flow signal in 8 lesions, low color signal in 9 lesions and an intense color signal in 1 lesion; CEUS identified 17/18 lesions with the undetected lesion being the smallest one (1.2 cm) located in the upper pelvicalyceal system. Semi-quantitative analysis produced different data for high-grade and low-grade urothelial cell carcinoma (UCC). All detected upper urinary tract masses were UCCs. MRU, MDCTU and grayscale US overestimated the tumor size, while CEUS was the most accurate. CEUS is useful for evaluating upper urinary tract masses as this method permits differentiation between high-grade and low-grade tumors as well as distinction of the tumor from the adjacent structures and accurate mass measurements. © Georg Thieme Verlag KG Stuttgart · New York.

  19. Quantitative characterization of inertial confinement fusion capsules using phase contrast enhanced x-ray imaging

    SciTech Connect

    Kozioziemski, B.J.; Koch, J.A.; Barty, A.; Martz, H.E. Jr.; Lee, Wah-Keat; Fezzaa, Kamel

    2005-03-15

    Current designs for inertial confinement fusion capsules for the National Ignition Facility consist of a solid deuterium-tritium (D-T) fuel layer inside of a copper doped beryllium, Be(Cu), shell. Phase contrast enhanced x-ray imaging is shown to render the D-T layer visible inside the Be(Cu) shell. Phase contrast imaging is experimentally demonstrated for several surrogate capsules and validates computational models. Polyimide and low density divinyl benzene foam shells were imaged at the Advanced Photon Source synchrotron. The surrogates demonstrate that phase contrast enhanced imaging provides a method to characterize surfaces when absorption imaging cannot be used. Our computational models demonstrate that a rough surface can be accurately characterized using phase contrast enhanced x-ray images.

  20. Quantitative Characterization of Inertial Confinement Fusion Capsules Using Phase Contrast Enhanced X-Ray Imaging

    SciTech Connect

    Kozioziemski, B J; Koch, J A; Barty, A; Martz, H E; Lee, W; Fezzaa, K

    2004-05-07

    Current designs for inertial confinement fusion capsules for the National Ignition Facility (NIF) consist of a solid deuterium-tritium (D-T) fuel layer inside of a copper doped beryllium capsule. Phase contrast enhanced x-ray imaging is shown to render the D-T layer visible inside the Be(Cu) capsule. Phase contrast imaging is experimentally demonstrated for several surrogate capsules and validates computational models. Polyimide and low density divinyl benzene foam capsules were imaged at the Advanced Photon Source synchrotron. The surrogates demonstrate that phase contrast enhanced imaging provides a method to characterize surfaces when absorption imaging cannot be used. Our computational models demonstrate that a rough surface can be accurately reproduced in phase contrast enhanced x-ray images.

  1. Dual-frequency transducer with a wideband PVDF receiver for contrast-enhanced, adjustable harmonic imaging

    NASA Astrophysics Data System (ADS)

    Kim, Jinwook; Lindsey, Brooks D.; Li, Sibo; Dayton, Paul A.; Jiang, Xiaoning

    2017-04-01

    Acoustic angiography is a contrast-enhanced, superharmonic microvascular imaging method. It has shown the capability of high-resolution and high-contrast-to-tissue-ratio (CTR) imaging for vascular structure near tumor. Dual-frequency ultrasound transducers and arrays are usually used for this new imaging technique. Stacked-type dual-frequency transducers have been developed for this vascular imaging method by exciting injected microbubble contrast agent (MCA) in the vessels with low-frequency (1-5 MHz), moderate power ultrasound burst waves and receiving the superharmonic responses from MCA by a high-frequency receiver (>10 MHz). The main challenge of the conventional dual-frequency transducers is a limited penetration depth (<25 mm) due to the insufficient receiving sensitivity for highfrequency harmonic signal detection. A receiver with a high receiving sensitivity spanning a wide superharmonic frequency range (3rd to 6th) enables selectable bubble harmonic detection considering the required penetration depth. Here, we develop a new dual-frequency transducer composed of a 2 MHz 1-3 composite transmitter and a polyvinylidene fluoride (PVDF) receiver with a receiving frequency range of 4-12 MHz for adjustable harmonic imaging. The developed transducer was tested for harmonic responses from a microbubble-injected vessel-mimicking tube positioned 45 mm away. Despite the long imaging distance (45 mm), the prototype transducer detected clear harmonic response with the contrast-to-noise ratio of 6-20 dB and the -6 dB axial resolution of 200-350 μm for imaging a 200 um-diameter cellulose tube filled with microbubbles.

  2. Management of incidental renal masses: Time to consider contrast-enhanced ultrasonography.

    PubMed

    Di Vece, Francesca; Tombesi, Paola; Ermili, Francesca; Sartori, Sergio

    2016-02-01

    Proliferation of imaging studies for different clinical purposes and continuous improvement of imaging technology have led to an increasing number of incidental findings of renal masses. It is estimated that over 50% of patients older than 50 years have at least one renal mass. The majority of incidental renal masses are simple cysts that can be easily diagnosed by conventional ultrasonography. However, some incidental renal masses are not simple cysts, and differentiation between benign and malignant entities requires further imaging modalities. In the past, multiphase contrast-enhanced computed tomography and magnetic resonance imaging were considered the primary imaging modalities used to characterize and stage complex cystic and solid renal lesions. Currently, contrast-enhanced ultrasonography represents a novel alternative to contrast-enhanced computed tomography and magnetic resonance imaging. Contrast-enhanced ultrasonography employs microbubble contrast agents that allow the study of different enhancement phases of the kidney without risk of nephrotoxicity and radiation exposure. The diagnostic accuracy of contrast-enhanced ultrasonography in the characterization of complex renal cysts is comparable to that of computed tomography and magnetic resonance imaging, and several studies have demonstrated its reliability also in identifying solid lesions such as pseudotumors, typical angiomyolipomas, and clear cell renal carcinomas. Considering the high incidence of incidental renal masses and the need for rapid and reliable diagnosis, contrast-enhanced ultrasonography could be proposed as the first step in the diagnostic work-up of renal masses because of its safety and cost effectiveness. In this paper, we propose a diagnostic algorithm for the characterization of cystic and solid renal masses.

  3. Targeted contrast-enhanced ultrasound imaging of angiogenesis in an orthotopic mouse tumor model of renal carcinoma.

    PubMed

    Wei, Shuping; Fu, Ninghua; Sun, Yu; Yang, Zhijian; Lei, Li; Huang, Pengfei; Yang, Bin

    2014-06-01

    Previous studies have reported that microbubbles bearing targeting ligands to molecular markers of angiogenesis can be successfully detected by ultrasound imaging in various animal models of solid cancer. In the present study, we sought to investigate the activity of microbubbles targeted to vascular endothelial growth factor receptor 2 (VEGFR2) in an orthotopic model of renal cell carcinoma (RCC). Microbubbles conjugated to an anti-VEGFR2 antibody (MBV) were compared with microbubbles conjugated to an isotype control antibody (MBC) or naked microbubbles (MBN). An orthotopic mouse model of human RCC was established by surgically implanting an established tumor within the renal capsule in mice. Tumor growth and blood flow were verified by B-mode and color Doppler ultrasound imaging. VEGFR2 expression within the tumor and renal parenchyma was detected by immunohistochemistry. The duration of contrast enhancement of MBV was much longer than those of MBN and MBC when assessed over 10 min. The baseline-subtracted contrast intensity within the tumor was higher for MBV than for MBC and MBN (p < 0.01). Additionally, the contrast intensity for MBV was significantly higher in the tumor region than in normal parenchyma (p < 0.01). Microbubbles targeting VEGFR2 exhibit suitable properties for imaging angiogenesis in orthotopic models of renal cell carcinoma, with potential applications in life science research and clinical medicine. Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  4. Contrast-enhanced cardiac MRI before coronary artery bypass surgery: impact of myocardial scar extent on bypass flow.

    PubMed

    Hunold, Peter; Massoudy, Parwis; Boehm, Claudia; Schlosser, Thomas; Nassenstein, Kai; Knipp, Stephan; Eggebrecht, Holger; Thielmann, Matthias; Erbel, Raimund; Jakob, Heinz; Barkhausen, Jörg

    2008-12-01

    The aim of the study was to relate the extent of myocardial late gadolinium enhancement (LGE) in cardiac MRI to intraoperative graft flow in patients undergoing coronary artery bypass graft (CABG) surgery. Thirty-three CAD patients underwent LGE MRI before surgery using an inversion-recovery GRE sequence (turboFLASH). Intraoperative graft flow in Doppler ultrasonography was compared with the scar extent in each coronary vessel territory. One hundred and fourteen grafts were established supplying 86 of the 99 vessel territories. A significant negative correlation was found between scar extent and graft flow (r = -0.4, p < 0.0001). Flow in grafts to territories with no or small subendocardial scar was significantly higher than in grafts to territories with broad nontransmural or transmural scar (75 +/- 39 vs. 38 +/- 26 cc min(-1); p < 0.0001). In summary, the extent of myocardial scar as defined by contrast-enhanced MRI predicts coronary bypass graft flow. Beyond the probability of functional recovery, preoperative MRI might add value to surgery planning by predicting midterm bypass graft patency.

  5. Prostate cancer transrectal HIFU ablation: detection of local recurrences using T2-weighted and dynamic contrast-enhanced MRI.

    PubMed

    Rouvière, Olivier; Girouin, Nicolas; Glas, Ludivine; Ben Cheikh, Alexandre; Gelet, Albert; Mège-Lechevallier, Florence; Rabilloud, Muriel; Chapelon, Jean-Yves; Lyonnet, Denis

    2010-01-01

    The objective was to evaluate T2-weighted (T2w) and dynamic contrast-enhanced (DCE) MRI in detecting local cancer recurrences after prostate high-intensity focused ultrasound (HIFU) ablation. Fifty-nine patients with biochemical recurrence after prostate HIFU ablation underwent T2-weighted and DCE MRI before transrectal biopsy. For each patient, biopsies were performed by two operators: operator 1 (blinded to MR results) performed random and colour Doppler-guided biopsies ("routine biopsies"); operator 2 obtained up to three cores per suspicious lesion on MRI ("targeted biopsies"). Seventy-seven suspicious lesions were detected on DCE images (n = 52), T2w images (n = 2) or both (n = 23). Forty patients and 41 MR lesions were positive at biopsy. Of the 36 remaining MR lesions, 20 contained viable benign glands. Targeted biopsy detected more cancers than routine biopsy (36 versus 27 patients, p = 0.0523). The mean percentages of positive cores per patient and of tumour invasion of the cores were significantly higher for targeted biopsies (p < 0.0001). The odds ratios of the probability of finding viable cancer and viable prostate tissue (benign or malignant) at targeted versus routine biopsy were respectively 3.35 (95% CI 3.05-3.64) and 1.38 (95% CI 1.13-1.63). MRI combining T2-weighted and DCE images is a promising method for guiding post-HIFU biopsy towards areas containing recurrent cancer and viable prostate tissue.

  6. Regions of low density in the contrast-enhanced pituitary gland: normal and pathologic processes

    SciTech Connect

    Chambers, E.F.; Turski, P.A.; LaMasters, D.; Newton, T.H.

    1982-07-01

    The incidence of low-density regions in the contrast-enhanced pituitary gland and the possible causes of these regions were investigated by a retrospective review of computed tomographic (CT) scans of the head in 50 patients and autopsy specimens of the pituitary in 100 other patients. It was found that focal areas of low density within the contrast enhanced pituitary gland can be caused by various normal and pathologic conditions such as pituitary microadenomas, pars intermedia cysts, foci of metastasis, infarcts, epidermoid cysts, and abscesses. Although most focal low-density regions probably represent pituitary microadenomas, careful clinical correlation is needed to establish a diagnosis.

  7. Photonic crystal slabs for surface contrast enhancement in microscopy of transparent objects.

    PubMed

    Nazirizadeh, Yousef; Becker, Tim; Reverey, Julia; Selhuber-Unkel, Christine; Rapoport, Daniel H; Lemmer, Uli; Gerken, Martina

    2012-06-18

    In optical microscopy the contrast of transparent objects achieved with conventional methods is often not satisfactory, for example for the automated recognition of cells. In this paper we present a nano-optical label-free approach for contrast enhancement based on photonic crystal slabs (PCS) as the specimen holder. Quasi-guided modes inside these structures cause an intrinsic color of the PCS, which strongly depends on the wavelength and the quality factor of the optical mode. Objects on the surface of the PCS experience a significant color and intensity contrast enhancement, as they change properties of the optical modes.

  8. Evolution of pulmonary perfusion defects demonstrated with contrast-enhanced dynamic MR perfusion imaging.

    PubMed

    Howarth, N R; Beziat, C; Berthezène, Y

    1999-01-01

    Pulmonary perfusion defects can be demonstrated with contrast-enhanced dynamic MR perfusion imaging. We present the case of a patient with a pulmonary artery sarcoma who presented with a post-operative pulmonary embolus and was followed in the post-operative period with dynamic contrast-enhanced MR perfusion imaging. This technique allows rapid imaging of the first passage of contrast material through the lung after bolus injection in a peripheral vein. To our knowledge, this case report is the first to describe the use of this MR technique in showing the evolution of peripheral pulmonary perfusion defects associated with pulmonary emboli.

  9. Contrast enhanced-magnetic resonance imaging as a surrogate to map verteporfin delivery in photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Samkoe, Kimberley S.; Bryant, Amber; Gunn, Jason R.; Pereira, Stephen P.; Hasan, Tayyaba; Pogue, Brian W.

    2013-12-01

    The use of in vivo contrast-enhanced magnetic resonance (MR) imaging as a surrogate for photosensitizer (verteporfin) dosimetry in photodynamic therapy of pancreas cancer is demonstrated by correlating MR contrast uptake to ex vivo fluorescence images on excised tissue. An orthotopic pancreatic xenograft mouse model was used for the study. A strong correlation (r=0.57) was found for bulk intensity measurements of T1-weighted gadolinium enhancement and verteporfin fluorescence in the tumor region of interest. The use of contrast-enhanced MR imaging shows promise as a method for treatment planning and photosensitizer dosimetry in human photodynamic therapy (PDT) of pancreas cancer.

  10. Coherence based contrast enhancement in x-ray radiography with a photoelectron microscope

    NASA Astrophysics Data System (ADS)

    Hwu, Y.; Lai, B.; Mancini, D. C.; Je, J. H.; Noh, D. Y.; Bertolo, M.; Tromba, G.; Margaritondo, G.

    1999-10-01

    We show that a photoelectron spectromicroscope of the photoelectron emission microscope type can be used as an x-ray imaging detector for radiology. Using high penetration hard-x-ray photons (wavelength <0.1 nm), samples as thick as a few millimeters can be imaged with submicron resolution. The high imaging resolution enables us to substantially decrease the object-detector distance needed to observe coherent based contrast enhancement with respect to the standard film-based detection technique. Our result implies several advantages, the most important being a marked reduction of the required source emittance for contrast enhanced radiology.

  11. Noninvasive assessment of pulmonary emphysema using dynamic contrast-enhanced magnetic resonance imaging.

    PubMed

    Morino, Shigeyuki; Toba, Toshinari; Araki, Masato; Azuma, Takashi; Tsutsumi, Sadami; Tao, Hiroyuki; Nakamura, Tatsuo; Nagayasu, Takeshi; Tagawa, Tsutomu

    2006-01-01

    Emphysema tends to be complicated by diffuse abnormalities in the pulmonary peripheral microvasculature. The aim of this study was to evaluate whether dynamic contrast-enhanced magnetic resonance imaging (MRI) could provide a valid assessment of pulmonary blood flow as an indicator of the severity of emphysema. To do this, the authors compared MRI data with the pathological findings in lung tissue. Dynamic contrast-enhanced MRI is a noninvasive method and can be used to repeatedly monitor clinicopathological severity. Using MRI clear pulmonary vascular information can be obtained easily, and the relative pulmonary blood flow in the lung parenchyma can be quantified.

  12. Role of intra-operative contrast-enhanced ultrasound (CEUS) in robotic-assisted nephron-sparing surgery.

    PubMed

    Alenezi, Ahmad N; Karim, Omer

    2015-03-01

    This review examines studies of intra-operative contrast-enhanced ultrasound (CEUS) and its emerging role and advantages in robotic-assisted nephron-sparing surgery. Contrast-enhanced ultrasound is a technology that combines the use of second-generation contrast agents consisting of microbubbles with existent ultrasound techniques. Until now, this novel technology has aided surgeons with procedures involving the liver. However, with recent advances in the CEUS technique and the introduction of robotics in nephron-sparing surgery, CEUS has proven to be efficacious in answering several clinical questions with respect to the kidneys. In addition, the introduction of the microbubble-based contrast agents has increased the image quality and signal uptake by the ultrasound probe. This has led to better, enhanced scanning of the macro and microvasculature of the kidneys, making CEUS a powerful diagnostic modality. This imaging method is capable of further lowering the learning curve and warm ischemia time (WIT) during robotic-assisted nephron-sparing surgery, with its increased level of capillary perfusion and imaging. CEUS has the potential to increase the sensitivity and specificity of intra-operative images, and can significantly improve the outcome of robotic-assisted nephron-sparing surgery by increasing the precision and diagnostic insight of the surgeon. The purpose of this article is to review the practical and potential uses of CEUS as an intra-operative imaging technique during robotic-assisted nephron-sparing surgery.

  13. Comparison between survey radiography, B-mode ultrasonography, contrast-enhanced ultrasonography and contrast-enhanced multi-detector computed tomography findings in dogs with acute abdominal signs.

    PubMed

    Shanaman, Miriam M; Schwarz, Tobias; Gal, Arnon; O'Brien, Robert T

    2013-01-01

    Contrast-enhanced multi-detector computed tomography (CE-MDCT) is used routinely in evaluating human patients with acute abdominal symptoms. Contrast-enhanced ultrasound (CEUS) continues to be in its infancy as it relates to evaluation of the acute abdomen. The purpose of this study was to compare survey radiography, B-mode ultrasound, CEUS, and CE-MDCT findings in canine patients presenting with acute abdominal signs; with a focus on the ability to differentiate surgical from non-surgical conditions. Nineteen dogs were prospectively enrolled. Inclusion required a clinical diagnosis of acute abdominal signs and confirmed surgical or non-surgical causes for the clinical signs. Agreement for the majority of recorded imaging features was at least moderate. There was poor agreement in the identification of pneumoperitoneum and in the comparison of pancreatic lesion dimensions for B-mode vs. CEUS. The CT feature of fat stranding was detected in cases including, but not limited to, gastric neoplasia with perforation, pancreatitis, and small intestinal foreign body. Ultrasound underestimated the size and number of specific lesions when compared with CE-MDCT. Contrast-enhanced ultrasound was successful in detecting bowel and pancreatic perfusion deficits that CE-MDCT failed to identify. Accuracy for differentiation of surgical vs. non-surgical conditions was high for all modalities; 100%, 94%, and 94% for CE-MDCT, ultrasonography and survey radiography respectively. Findings indicated that CE-MDCT is an accurate screening test for differentiating surgical from non-surgical acute abdominal conditions in dogs. Focused CEUS following CE-MDCT or B-mode ultrasonography may be beneficial for identifying potentially significant hypoperfused lesions. © 2013 Veterinary Radiology & Ultrasound.

  14. Evaluation of liver parenchyma and perfusion using dynamic contrast-enhanced computed tomography and contrast-enhanced ultrasonography in captive green iguanas (Iguana iguana) under general anesthesia

    PubMed Central

    2014-01-01

    Background Contrast-enhanced diagnostic imaging techniques are considered useful in veterinary and human medicine to evaluate liver perfusion and focal hepatic lesions. Although hepatic diseases are a common occurrence in reptile medicine, there is no reference to the use of contrast-enhanced ultrasound (CEUS) and contrast-enhanced computed tomography (CECT) to evaluate the liver in lizards. Therefore, the aim of this study was to evaluate the pattern of change in echogenicity and attenuation of the liver in green iguanas (Iguana iguana) after administration of specific contrast media. Results An increase in liver echogenicity and density was evident during CEUS and CECT, respectively. In CEUS, the mean ± SD (median; range) peak enhancement was 19.9% ± 7.5 (18.3; 11.7-34.6). Time to peak enhancement was 134.0 ± 125.1 (68.4; 59.6-364.5) seconds. During CECT, first visualization of the contrast medium was at 3.6 ± 0.5 (4; 3-4) seconds in the aorta, 10.7 ± 2.2 (10.5; 7-14) seconds in the hepatic arteries, and 15 ± 4.5 (14.5; 10-24) seconds in the liver parenchyma. Time to peak was 14.1 ± 3.4 (13; 11-21) and 31 ± 9.6 (29; 23-45) seconds in the aorta and the liver parenchyma, respectively. Conclusion CEUS and dynamic CECT are practical means to determine liver hemodynamics in green iguanas. Distribution of contrast medium in iguana differed from mammals. Specific reference ranges of hepatic perfusion for diagnostic evaluation of the liver in iguanas are necessary since the use of mammalian references may lead the clinician to formulate incorrect diagnostic suspicions. PMID:24885935

  15. Non-contrast enhanced MRI for evaluation of breast lesions: comparison of non-contrast enhanced high spectral and spatial resolution (HiSS) images vs. contrast enhanced fat-suppressed images

    PubMed Central

    Medved, Milica; Fan, Xiaobing; Abe, Hiroyuki; Newstead, Gillian M.; Wood, Abbie M.; Shimauchi, Akiko; Kulkarni, Kirti; Ivancevic, Marko K.; Pesce, Lorenzo L.; Olopade, Olufunmilayo I.; Karczmar, Gregory S.

    2011-01-01

    RATIONALE AND OBJECTIVES To evaluate high spectral and spatial resolution (HiSS) MRI for diagnosis of breast cancer without injection of contrast media: to compare the performance of pre-contrast HiSS images to conventional contrast-enhanced fat-suppressed T1-weighted images, based on image quality and in the task of classifying benign and malignant breast lesions. MATERIALS AND METHODS Ten benign and 44 malignant lesions were imaged at 1.5T with HiSS (pre-contrast administration) and conventional fat-suppressed imaging (3–10 min post-contrast). This set of 108 images, after randomization, was evaluated by three experienced radiologists blinded to the imaging technique. BIRADS morphologic criteria (lesion shape; lesion margin; internal signal intensity pattern) and final assessment were used to measure reader performance. Image quality was evaluated based on boundary delineation and quality of fat suppression. An overall probability of malignancy was assigned to each lesion for HiSS and conventional images separately. RESULTS On boundary delineation and quality of fat-suppression, pre-contrast HiSS scored similarly to conventional post-contrast MRI. On benign vs. malignant lesion separation, there was no statistically significant difference in ROC performance between HiSS and conventional MRI, and HiSS met a reasonable non-inferiority condition. CONCLUSION Pre-contrast HiSS imaging is a promising approach for showing lesion morphology without blooming and other artifacts caused by contrast agents. HiSS images could be used to guide subsequent dynamic contrast-enhanced MRI scans, to maximize spatial and temporal resolution in suspicious regions. HiSS MRI without contrast agent injection may be particularly important for patients at risk for contrast-induced nephrogenic systemic fibrosis, or allergic reactions. PMID:21962476

  16. Medical Image Visual Appearance Improvement Using Bihistogram Bezier Curve Contrast Enhancement: Data from the Osteoarthritis Initiative

    PubMed Central

    Gan, Hong-Seng; Swee, Tan Tian; Abdul Karim, Ahmad Helmy; Sayuti, Khairil Amir; Abdul Kadir, Mohammed Rafiq; Tham, Weng-Kit; Wong, Liang-Xuan; Chaudhary, Kashif T.; Yupapin, Preecha P.

    2014-01-01

    Well-defined image can assist user to identify region of interest during segmentation. However, complex medical image is usually characterized by poor tissue contrast and low background luminance. The contrast improvement can lift image visual quality, but the fundamental contrast enhancement methods often overlook the sudden jump problem. In this work, the proposed bihistogram Bezier curve contrast enhancement introduces the concept of “adequate contrast enhancement” to overcome sudden jump problem in knee magnetic resonance image. Since every image produces its own intensity distribution, the adequate contrast enhancement checks on the image's maximum intensity distortion and uses intensity discrepancy reduction to generate Bezier transform curve. The proposed method improves tissue contrast and preserves pertinent knee features without compromising natural image appearance. Besides, statistical results from Fisher's Least Significant Difference test and the Duncan test have consistently indicated that the proposed method outperforms fundamental contrast enhancement methods to exalt image visual quality. As the study is limited to relatively small image database, future works will include a larger dataset with osteoarthritic images to assess the clinical effectiveness of the proposed method to facilitate the image inspection. PMID:24977191

  17. Contrast-enhanced ultrasonography in Takayasu arteritis: watching and monitoring the arterial inflammation.

    PubMed

    Herlin, Bastien; Baud, Jean-Michel; Chadenat, Marie-Laure; Pico, Fernando

    2015-10-09

    A 43-year-old man was diagnosed with Takayasu arteritis, and treated with methotrexate and corticosteroids. While under treatment and with normal biological inflammatory parameters, he experienced an ischaemic stroke, successfully treated with intravenous thrombolysis (alteplase). The B-mode ultrasound examination revealed circumferential wall thickening of the left common carotid artery. Contrast-enhanced ultrasonography showed a progressive arterial wall enhancement of the left common carotid artery. This pathological enhancement indicates neovascularisation of the arterial wall, which is supposed to correlate with active vascular inflammation. After an increase in immunosuppressive treatment, follow-up contrast-enhanced ultrasonography no longer showed artery wall enhancement. Contrast-enhanced ultrasound examination is an inexpensive, reproducible and minimally invasive method, providing dynamic information on arterial wall neovascularisation and thus inflammation. This case illustrates that contrast-enhanced ultrasonography can be a useful tool for the management and follow-up of Takayasu arteritis, and its use as a marker of disease activity and arterial inflammation in Takayasu arteritis should be evaluated in further studies.

  18. Comparison of the Specificity of MREIT and Dynamic Contrast-Enhanced MRI in Breast Cancer

    DTIC Science & Technology

    2007-05-01

    Method; EIS, Electrical Impedance Scanning; OPAMP, Operational Amplifier; SVD, Singular Value Decomposition; NEX, Number of Excitations ; CE- MRI ... simulate a low conductivity region (Fig. 1). The plane of the disk was placed perpendicular to the main static MRI field. Four copper electrodes each...and Dynamic Contrast-Enhanced MRI in Breast Cancer PRINCIPAL INVESTIGATOR: Ozlem Birgul, Ph.D. CONTRACTING ORGANIZATION

  19. Two improved forensic methods of detecting contrast enhancement in digital images

    NASA Astrophysics Data System (ADS)

    Lin, Xufeng; Wei, Xingjie; Li, Chang-Tsun

    2014-02-01

    Contrast enhancements, such as histogram equalization or gamma correction, are widely used by malicious attackers to conceal the cut-and-paste trails in doctored images. Therefore, detecting the traces left by contrast enhancements can be an effective way of exposing cut-and-paste image forgery. In this work, two improved forensic methods of detecting contrast enhancement in digital images are put forward. More specifically, the first method uses a quadratic weighting function rather than a simple cut-off frequency to measure the histogram distortion introduced by contrast enhancements, meanwhile the averaged high-frequency energy measure of his- togram is replaced by the ratio taken up by the high-frequency components in the histogram spectrum. While the second improvement is achieved by applying a linear-threshold strategy to get around the sensitivity of threshold selection. Compared with their original counterparts, these two methods both achieve better performance in terms of ROC curves and real-world cut-and-paste image forgeries. The effectiveness and improvement of the two proposed algorithms are experimentally validated on natural color images captured by commercial camera.

  20. Detection of anomalous splenic artery aneurysms with three-dimensional contrast-enhanced MR angiography.

    PubMed

    Liu, Qi; Lu, Jian Ping; Wang, Fei; Wang, Li; Jin, Ai Guo; Wang, Jian; Tian, Jian Min

    2009-11-01

    Aneurysms of the splenic artery which arise anomalously from the superior mesenteric artery are extremely rare but clinically important because of their life-threatening hemorrhage. Diagnostic imaging plays an important role in the diagnosis and conducting treatment strategy. The aim of this study was to evaluate the detection of anomalous splenic artery aneurysms with 3D contrast-enhanced MR angiography. 3D contrast-enhanced MR angiography was performed in six patients with anomalous splenic artery aneurysms. The mean diameter of six aneurysms was 3.9 cm. All of them were saccular and located at the origin of the splenic artery that arose anomalously from the root of the superior mesenteric artery. 3D contrast-enhanced MR angiography clearly demonstrated the aneurysm's location, size, morphology, visceral arterial variations, and was superior to DSA in three-dimensional display of the aneurysm and its relationship with surrounding vessels and organs. Two patients underwent open vascular surgery and three endovascular procedure. 3D contrast-enhanced MR angiography is a noninvasive and accurate technique for diagnosis of anomalous splenic artery aneurysms. Its 3D anatomic information is very helpful for treatment planning. It can be used as one of the first choice examinations for anomalous splenic artery aneurysms.

  1. Standardized perfusion value: universal CT contrast enhancement scale that correlates with FDG PET in lung nodules.

    PubMed

    Miles, K A; Griffiths, M R; Fuentes, M A

    2001-08-01

    The standardized enhancement value and standardized perfusion value allow comparison between different methods for quantification of contrast enhancement during computed tomography (CT). Standard perfusion values calculated from CT measurements of perfusion within pulmonary nodules compared favorably with those derived from previously reported enhancement data and correlated with standardized uptake values obtained from positron emission tomographic images (r = 0.8, P <.01).

  2. Regularized Reconstruction of Dynamic Contrast-Enhanced MR Images for Evaluation of Breast Lesions

    DTIC Science & Technology

    2010-09-01

    V. Knopp, E. Weiss, H. P. Sinn, J. Mattern, H. Junkermann, J. Radeleff, A. Magener, G. Brix , S. Delorme, I. Zuna, and G. . Kaick, “Pathophysiologic...basis of contrast enhancement in breast tumors,” J. Mag. Res. Im., vol. 10, no. 3, pp. 260–6, Sept. 1999. [11] P. S. Tofts, G. Brix , D. L. Buckley, J. L

  3. Successful diagnosis of pulmonary artery sarcoma by contrast-enhanced computed tomography.

    PubMed

    Panfeng, Xu; Zheying, Zhang; Jie, Wang; Jianying, Zhou; Xiaodong, Teng

    2008-07-01

    Pulmonary artery sarcoma is a rare tumor of the cardiovascular system. We reported a case of primary pulmonary artery sarcoma. In this case, the patient was misdiagnosed with tuberculosis for nearly 1 year and diagnosed by contrast-enhanced computed tomography and histopathologic examination at last.

  4. Attenuation Correction and Normalisation for Quantification of Contrast Enhancement in Ultrasound Images of Carotid Arteries.

    PubMed

    Cheung, Wing Keung; Gujral, Dorothy M; Shah, Benoy N; Chahal, Navtej S; Bhattacharyya, Sanjeev; Cosgrove, David O; Eckersley, Robert J; Harrington, Kevin J; Senior, Roxy; Nutting, Christopher M; Tang, Meng-Xing

    2015-07-01

    An automated attenuation correction and normalisation algorithm was developed to improve the quantification of contrast enhancement in ultrasound images of carotid arteries. The algorithm first corrects attenuation artefact and normalises intensity within the contrast agent-filled lumen and then extends the correction and normalisation to regions beyond the lumen. The algorithm was first validated on phantoms consisting of contrast agent-filled vessels embedded in tissue-mimicking materials of known attenuation. It was subsequently applied to in vivo contrast-enhanced ultrasound (CEUS) images of human carotid arteries. Both in vitro and in vivo results indicated significant reduction in the shadowing artefact and improved homogeneity within the carotid lumens after the correction. The error in quantification of microbubble contrast enhancement caused by attenuation on phantoms was reduced from 55% to 5% on average. In conclusion, the proposed method exhibited great potential in reducing attenuation artefact and improving quantification in contrast-enhanced ultrasound of carotid arteries. Copyright © 2015 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  5. Correlations in photoacoustic estimates of tumor oxygenation during novel cancer therapies with power Doppler measurements (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Hysi, Eno; Wirtzfeld, Lauren A.; Al-Mahrouki, Azza; Elfarnawany, Mai; Lacefield, James C.; Czarnota, Gregory J.; Kolios, Michael C.

    2017-03-01

    Photoacoustic (PA) imaging of tumor oxygenation can be used to monitor vascular-targeted novel therapies. This study examines how a combination treatment, ultrasound-microbubbles (USMB)/radiation-therapy (XRT) alters oxygen saturation (sO2) estimates, which are then compared to power Doppler (PD) assessments of tumor vascularity. SCID mice were inoculated with subcutaneous, hind-leg PC3 tumors. The treatment consisted of XRT/MB (XRT: 8Gy/single-fraction; USMB: 3%/500 kHz/570kPa; n=3), USMB (n=3) and XRT (n=5) alone and untreated control (n=5). PA/PD imaging was acquired pre-treatment and 2h/24h post-treatment using the VevoLAZR (21 MHz, 750/850 nm). The volumetric tumor sO2 was quantified using histogram distributions and the average mode was computed. The vascularization index (VI), a PD metric of tumor vessel density, was studied along with the sO2 mode by comparing changes at 2h with pre-treatment. Mice whose pre-treatment sO2 levels were over 65%, exhibited a 15% drop in oxygenation at 2h, remaining unchanged by 24h. Examining the sO2 and VI relationships revealed differences between the groups. All groups (except control) exhibited a positive correlation when the ∆VI was plotted as a function of ∆sO2 (r2≥0.85). Mice in the XRT/MB group had the largest slope (11.7) suggesting that a change in sO2 was accompanied by the largest change in vessel density. The slope of the USMB and XRT treatments was 5.6 and 2.9, respectively. The combination treatment induced the largest changes in vessel density and sO2. Early PA estimates of tumor oxygenation appear to correlate with the treatment-induced vascular changes. Such measure could potentially be used for predicting treatment outcome.

  6. Pulse subtraction Doppler

    NASA Astrophysics Data System (ADS)

    Mahue, Veronique; Mari, Jean Martial; Eckersley, Robert J.; Caro, Colin G.; Tang, Meng-Xing

    2010-01-01

    Recent advances have demonstrated the feasibility of molecular imaging using targeted microbubbles and ultrasound. One technical challenge is to selectively detect attached bubbles from those freely flowing bubbles and surrounding tissue. Pulse Inversion Doppler is an imaging technique enabling the selective detection of both static and moving ultrasound contrast agents: linear scatterers generate a single band Doppler spectrum, while non-linear scatterers generate a double band spectrum, one being uniquely correlated with the presence of contrast agents and non-linear tissue signals. We demonstrate that similar spectrums, and thus the same discrimination, can be obtained through a Doppler implementation of Pulse Subtraction. This is achieved by reconstructing a virtual echo using the echo generated from a short pulse transmission. Moreover by subtracting from this virtual echo the one generated from a longer pulse transmission, it is possible to fully suppress the echo from linear scatterers, while for non-linear scatterers, a signal will remain, allowing classical agent detection. Simulations of a single moving microbubble and a moving linear scatterer subject to these pulses show that when the virtual echo and the long pulse echo are used to perform pulsed Doppler, the power Doppler spectrum allows separation of linear and non-linear moving scattering. Similar results are obtained on experimental data acquired on a flow containing either microbubble contrast agents or linear blood mimicking fluid. This new Doppler method constitutes an alternative to Pulse Inversion Doppler and preliminary results suggest that similar dual band spectrums could be obtained by the combination of any non-linear detection technique with Doppler demodulation.

  7. Effect of metformin treatment on endometrial vascular indices in anovulatory obese/overweight women with polycystic ovarian syndrome using three-dimensional power doppler ultrasonography.

    PubMed

    Mohsen, Iman Abdel; Elkattan, Eman; Nabil, Hala; Khattab, Sherif

    2013-06-01

    Metformin has been shown to be an effective treatment for anovulatory polycystic ovary syndrome (PCOS) patients in terms of menstrual cyclicity, ovulation, and pregnancy, as well as reduction of early miscarriage rate. The aim of the study is to assess the effect of metformin on the endometrial vascular indices in anovulatory obese PCOS women using three-dimensional power Doppler sonography (3DPDUS). A prospective study was set to determine the beneficial effects of metformin on PCOS patients. Fifty anovulatory obese PCOS patients were compared with another 50 healthy volunteers who were age- and body mass index-matched (control group). PCOS patients were treated with metformin (Glucophage; MerckSerono) 850 mg 3 times a day for 6 months. Assessment of the endometrial thickness and volume, uterine Doppler indices, and Doppler vascular indices of the endometrium and subendometrium in the periovulatory and midluteal phases were performed with 3DPDUS. There was a significant increase in the endometrial thickness, endometrial volume, and endometrial and subendometrial vascularity indices (vascularization index, flow index, vascularization flow index) after 6 months of metformin treatment in PCOS women, whereas there was no change in the resistance index and the pulsatility index of the uterine artery in both periovulatory and midluteal phases. Metformin, owing to its metabolic, endocrine, vascular, and anti-inflammatory effects, improves markers of endometrial receptivity. Copyright © 2012 Wiley Periodicals, Inc.

  8. Doppler echocardiography

    SciTech Connect

    Labovitz, A.J.; Williams, G.A.

    1988-01-01

    The authors are successful in presenting a basic book on clinical quantitative Doppler echocardiography. It is not intended to be a comprehensive text, but it does cover clinical applications in a succinct fashion. Only the more common diseases in the adult are considered. The subjects are presented logically and are easy to comprehend. The illustrations are good, and the book is paperbound. The basic principles of Doppler echocardiography are presented briefly. The book ends with chapters on left ventricular function (stroke volume and cardiac output), congenital heart disease, and color Doppler echo-cardiography. There are numerous references and a good glossary and index.

  9. Improvement of image quality of low radiation dose abdominal CT by increasing contrast enhancement.

    PubMed

    Watanabe, Haruo; Kanematsu, Masayuki; Miyoshi, Toshiharu; Goshima, Satoshi; Kondo, Hiroshi; Moriyama, Noriyuki; Bae, Kyongtae T

    2010-10-01

    The purpose of this study was to evaluate the effects of noise index and contrast material dose on radiation dose, contrast enhancement, image noise, and image quality in abdominal CT. Contrast-enhanced abdominal CT with tube current modulation was performed on 195 patients. The patients were prospectively randomized into three groups of equal size (protocol A, noise index of 12 HU and 521 mg I/kg; protocol B, 15 HU and 521 mg I/kg; protocol C, 15 HU and 600 mg I/kg). Scanning was initiated 5 and 45 seconds after aortic enhancement reached 100 HU. Attenuation was measured in the aorta, portal vein, and liver. Transverse CT images were qualitatively graded for diagnostic acceptability and image noise. Arterial phase volume-rendered and multiplanar reformatted (MPR) images and portal venous phase MPR CT angiograms were qualitatively graded for depiction of vessels. Contrast enhancement, objective image noise, radiation dose, and qualitative grades were analyzed and compared among the three groups. The contrast enhancement values of the aorta, portal vein, and liver were higher in protocol C than in protocols A and B (p < 0.05). Objective image noise was greater in protocols B and C than in protocol A (p < 0.05). The radiation dose in protocols B and C was 31-32% lower than in protocol A (p < 0.001). Depiction of vessels, diagnostic acceptability, and subjective image noise were comparable in protocols A and C. Use of higher contrast enhancement can compensate for the degradation of image quality resulting from use of a low radiation dose for CT.

  10. Contrast-enhanced endoscopic ultrasound in discrimination between benign and malignant mediastinal and abdominal lymph nodes.

    PubMed

    Hocke, Michael; Menges, Markus; Topalidis, Theodor; Dietrich, Christoph F; Stallmach, Andreas

    2008-04-01

    Enlarged lymph nodes in the mediastinum reflect neoplastic, infectious or other diseases. The classification of these nodes is crucial in the management of the patient. Currently, only invasive measures obtaining tissue samples reach satisfying specificity. Contrast-enhanced endoscopic ultrasound (EUS) may offer a non-invasive alternative. A total of 122 patients (age: 63 +/- 15 years, 92 males, 30 females) with enlarged mediastinal and/or paraaortic lymph nodes diagnosed by CT scan were included in the study. EUS-guided fine needle aspiration was performed and cytologic specimens were diagnosed as representing a malignant or benign process in case of Papanicolau IV and V, or Papanicolau I and II, respectively. Based on cytology results, the investigated lymph nodes were classified as neoplastic (n = 48) or non-neoplastic lymph nodes. Using the B-mode criteria the preliminary diagnosis was confirmed in 64 out of 74 benign lymph nodes (specificity 86%). Regarding malignant lymph nodes 33 of 48 were confirmed (sensitivity 68%). Using the advanced contrast-enhanced EUS criteria the diagnosis was confirmed in 68 of 74 benign lymph nodes (specificity 91%). However, in case of malignant lymph nodes the number of correct diagnoses dropped to 29 of 48 lymph nodes (sensitivity 60%). The contrast-enhanced EUS criteria to identify benign lymph nodes and node enlargement in malignant lymphoma do not differ. If those ten patients with malignant lymphoma are excluded, the sensitivity of the contrast enhanced EUS for malignant lymph nodes rises to 73%. Contrast-enhanced EUS improves the specificity in diagnosing benign lymph nodes as compared to B-mode EUS. It does not improve the correct identification of malignant lymph nodes and cannot replace EUS-guided fine-needle aspiration.

  11. Preoperative detection and localization of accessory pudendal artery with contrast-enhanced MR angiography.

    PubMed

    Whang, Shin Young; Sung, Deuk Jae; Lee, Seun Ah; Park, Beom Jin; Kim, Min Ju; Cho, Sung Bum; Kim, Yun Hwan; Cheon, Jun

    2012-03-01

    To evaluate the diagnostic performance of contrast material-enhanced magnetic resonance (MR) angiography for preoperative detection and localization of accessory pudendal arteries (APAs) in patients with prostate cancer. This prospective study was approved by the institutional review board, and informed consent was obtained. Between July 2007 and December 2010, 127 patients underwent contrast-enhanced MR angiography following prostate MR imaging at 3.0 T before robot-assisted laparoscopic radical prostatectomy (RALP). APAs were defined as any arteries located in the periprostatic region and anastomosed with the common penile artery or its branches; they were then subclassified into lateral and apical APAs. For detecting and localizing APAs, MR angiograms were evaluated prospectively by one reader and retrospectively by two independent blinded readers. Diagnostic performance was determined on a per-patient basis by using surgical findings as the reference standard. In addition, the origin of APAs identified at both surgery and contrast-enhanced MR angiography was determined by consensus of two retrospective readers. Interreader agreements were assessed by using k statistics. At surgery, 19 APAs (seven right apical, three left apical, four right lateral, and five left lateral) were detected in 16 patients, and 16 of these APAs were localized in 13 patients at preoperative contrast-enhanced MR angiography. Prospectively, sensitivity, specificity, and accuracy of contrast-enhanced MR angiography for the localization of APAs were 81.3%, 93.7%, and 92.1%, while retrospectively they were 87.5%, 91.9%, and 91.3% for reader 2 and 75.0%, 90.1%, and 88.2% for reader 3, respectively. Overall interreader agreement was substantial (k = 0.795). Nine and seven APAs originated from the obturator artery and the inferior vesical artery, respectively. Contrast-enhanced MR angiography can be used for the preoperative detection of APAs in patients with prostate cancer. © RSNA, 2012.

  12. Contrast-enhanced ultrasonographic evaluation of adrenal glands in dogs with pituitary-dependent hyperadrenocorticism.

    PubMed

    Pey, Pascalline; Daminet, Sylvie; Smets, Pascale Marcel Yvonne; Duchateau, Luc; De Fornel-Thibaud, Pauline; Rosenberg, Dan; Saunders, Jimmy C H

    2013-03-01

    To assess vascular changes induced by hyperadrenocorticism of hyperplastic adrenal glands in dogs via contrast-enhanced ultrasonography. 12 dogs with pituitary-dependent hyperadrenocorticism (PDH) and 7 healthy control dogs ≥ 7 years old. Dogs were assigned to the PDH and control groups and to small-breed (n = 6), medium-breed (4), and large-breed (9) subgroups. Contrast-enhanced ultrasonography of both adrenal glands in each dog was performed with IV injections of contrast agent. Time-intensity curves for the adrenal cortex, adrenal medulla, and ipsilateral renal artery of both adrenal glands were generated. Perfusion variables (time to peak [TTP], upslope of wash-in phase, and downslope of washout phase) were calculated. Contrast-enhanced ultrasonography revealed no qualitative difference between PDH and control groups. Quantitatively, TTPs were longer in the adrenal cortex and adrenal medulla of the PDH group, compared with values for the control group, particularly in the adrenal cortex and adrenal medulla of the small-breed subgroup. Washout downslopes were lower for the renal artery, adrenal cortex, and adrenal medulla of the small-breed subgroup between the PDH and control groups. No other perfusion variables differed between groups. Contrast-enhanced ultrasonography of the adrenal glands in dogs with PDH revealed a delayed TTP in the adrenal cortex and adrenal medulla, compared with values for control dogs. Contrast-enhanced ultrasonography was able to detect vascular changes induced by hyperadrenocorticism. Further studies are needed to evaluate whether reference ranges for clinically normal dogs and dogs with PDH can be determined and applied in clinical settings.

  13. Quantitative assessment of placental perfusion by contrast-enhanced ultrasound in macaques and human subjects.

    PubMed

    Roberts, Victoria H J; Lo, Jamie O; Salati, Jennifer A; Lewandowski, Katherine S; Lindner, Jonathan R; Morgan, Terry K; Frias, Antonio E

    2016-03-01

    The uteroplacental vascular supply is a critical determinant of placental function and fetal growth. Current methods for the in vivo assessment of placental blood flow are limited. We demonstrate the feasibility of the use of contrast-enhanced ultrasound imaging to visualize and quantify perfusion kinetics in the intervillous space of the primate placenta. Pregnant Japanese macaques were studied at mid second trimester and in the early third trimester. Markers of injury were assessed in placenta samples from animals with or without contrast-enhanced ultrasound exposure (n = 6/group). Human subjects were recruited immediately before scheduled first-trimester pregnancy termination. All studies were performed with maternal intravenous infusion of lipid-shelled octofluoropropane microbubbles with image acquisition with a multipulse contrast-specific algorithm with destruction-replenishment analysis of signal intensity for assessment of perfusion. In macaques, the rate of perfusion in the intervillous space was increased with advancing gestation. No evidence of microvascular hemorrhage or acute inflammation was found in placental villous tissue and expression levels of caspase-3, nitrotyrosine and heat shock protein 70 as markers of apoptosis, nitrative, and oxidative stress, respectively, were unchanged by contrast-enhanced ultrasound exposure. In humans, placental perfusion was visualized at 11 weeks gestation, and preliminary data reveal regional differences in intervillous space perfusion within an individual placenta. By electron microscopy, we demonstrate no evidence of ultrastructure damage to the microvilli on the syncytiotrophoblast after first-trimester ultrasound studies. Use of contrast-enhanced ultrasound did not result in placental structural damage and was able to identify intervillous space perfusion rate differences within a placenta. Contrast-enhanced ultrasound imaging may offer a safe clinical tool for the identification of pregnancies that are at

  14. Ultrasound for diagnosis of carpal tunnel syndrome: comparison of different methods to determine median nerve volume and value of power Doppler sonography.

    PubMed

    Dejaco, Christian; Stradner, Martin; Zauner, Dorothea; Seel, Werner; Simmet, Nicole Elisabeth; Klammer, Alexander; Heitzer, Petra; Brickmann, Kerstin; Gretler, Judith; Fürst-Moazedi, Florentine C; Thonhofer, Rene; Husic, Rusmir; Hermann, Josef; Graninger, Winfried B; Quasthoff, Stefan

    2013-12-01

    To compare ultrasound measurement of median nerve cross-sectional area (CSA) at different anatomical landmarks and to assess the value of power Doppler signals within the median nerve for diagnosis of carpal tunnel syndrome (CTS). A prospective study of 135 consecutive patients with suspected CTS undergoing two visits within 3 months. A final diagnosis of CTS was established by clinical and electrophysiological findings. CSA was sonographically measured at five different levels at forearm and wrist; and CSA wrist to forearm ratios or differences were calculated. Intraneural power Doppler signals were semiquantitatively graded. Diagnostic values of different ultrasound methods were compared by receiver operating characteristic curves using SPSS. CTS was diagnosed in 111 (45.5%) wrists; 84 (34.4%) had no CTS and 49 (20.1%) were possible CTS cases. Diagnostic values were comparable for all sonographic methods to determine median nerve swelling, with area under the curves ranging from 0.75 to 0.85. Thresholds of 9.8 and 13.8 mm(2) for the largest CSA of the median nerve yielded a sensitivity of 92% and a specificity of 92%. A power Doppler score of 2 or greater had a specificity of 90% for the diagnosis of CTS. Sonographic median nerve volumetry revealed a good reliability with an intraclass correlation coefficient of 0.90 (95% CI 0.79 to 0.95). Sonographic assessment of median nerve swelling and vascularity allows for a reliable diagnosis of CTS. Determination of CSA at its maximal shape offers an easily reproducible tool for CTS classification in daily clinical practice.

  15. Effect of contrast enhancement prior to iteration procedure on image correction for soft x-ray projection microscopy

    NASA Astrophysics Data System (ADS)

    Jamsranjav, Erdenetogtokh; Shiina, Tatsuo; Kuge, Kenichi; Kinjo, Yasuhito; Nakamura, Yuichi; Shinohara, Kunio; Ito, Atsushi

    2016-01-01

    Soft X-ray microscopy is well recognized as a powerful tool of high-resolution imaging for hydrated biological specimens. Projection type of it has characteristics of easy zooming function, simple optical layout and so on. However the image is blurred by the diffraction of X-rays, leading the spatial resolution to be worse. In this study, the blurred images have been corrected by an iteration procedure, i.e., Fresnel and inverse Fresnel transformations repeated. This method was confirmed by earlier studies to be effective. Nevertheless it was not enough to some images showing too low contrast, especially at high magnification. In the present study, we tried a contrast enhancement method to make the diffraction fringes clearer prior to the iteration procedure. The method was effective to improve the images which were not successful by iteration procedure only.

  16. Effect of contrast enhancement prior to iteration procedure on image correction for soft x-ray projection microscopy

    SciTech Connect

    Jamsranjav, Erdenetogtokh Shiina, Tatsuo Kuge, Kenichi; Kinjo, Yasuhito; Nakamura, Yuichi; Shinohara, Kunio; Ito, Atsushi

    2016-01-28

    Soft X-ray microscopy is well recognized as a powerful tool of high-resolution imaging for hydrated biological specimens. Projection type of it has characteristics of easy zooming function, simple optical layout and so on. However the image is blurred by the diffraction of X-rays, leading the spatial resolution to be worse. In this study, the blurred images have been corrected by an iteration procedure, i.e., Fresnel and inverse Fresnel transformations repeated. This method was confirmed by earlier studies to be effective. Nevertheless it was not enough to some images showing too low contrast, especially at high magnification. In the present study, we tried a contrast enhancement method to make the diffraction fringes clearer prior to the iteration procedure. The method was effective to improve the images which were not successful by iteration procedure only.

  17. Inter- and intra-observer agreement of high-resolution ultrasonography and power Doppler in assessment of joint inflammation and bone erosions in patients with rheumatoid arthritis.

    PubMed

    Chávez-López, Mario Alfredo; Hernández-Díaz, Cristina; Moya, Carlos; Pineda, Carlos; Ventura-Ríos, Lucio; Möller, Ingrid; Naredo, Esperanza; Espinosa, Rolando; Peña, Angélica; Rosas-Cabral, Alejandro; Filippucci, Emilio

    2013-01-01

    To assess the inter- and intra-observer reproducibility of musculoskeletal ultrasonography among rheumatologist in detecting inflammatory and morphostructural changes in small joints of the hands in patients with rheumatoid arthritis (RA). Five members of the "Escuela de Ecografía del Colegio Mexicano de Reumatología" tested their inter- and intra-observer reliabilities in the assessment of basic sonographic findings of joint inflammation and bone erosion. Their results were compared to those obtained by a group of international experts from European League Against Rheumatism. A clinical rheumatologist evaluated eight RA patients. Five Siemens Acuson Antares ultrasound machines (7-13 MHz linear probes) were used. The OMERACT preliminary definitions of joint effusion, synovial hypertrophy, bone erosions and tenosynovitis were adopted. Inter-observer and intra-observer agreement was calculated by overall agreement and kappa statistics. Mean kappa value for joint effusion was good, 0.654 (85%); synovial hypertrophy, 0.550 (77.2%); power Doppler signal, 0.550 (82.5%); bone erosions, 0.549 (81%); and tenosynovitis, 0.500 (91.5%). Mean and overall intra-observer agreement for semiquantitative score was good for joint effusion, 0.630 (77.2%) and bone erosions, 0.605 (56.25%); and moderate to synovial hypertrophy, 0.476 (65%) and power Doppler signal, 0.471 (80%). Mean kappa value for joint effusion was 0.381 (95%), synovial hypertrophy, 0.447 (72%); power Doppler signal, 0.496 (81%); bone erosions, 0.294 (81%); and tenosynovitis, 0.030 (66%). Mean and overall inter-observer agreement for semiquantitative score was poor for joint effusion, 0.325 (57%) and bone erosions, 0.360 (43%); and moderate to synovial hypertrophy, 0.431 (55%) and power Doppler signal, 0.496 (81%). Intra-observer variability reached the highest levels of agreement. Factors related to the experience of the rheumatologist, the time spent in each examination and knowledge of the software ultrasound

  18. Fabrication of a PMN-PT Single Crystal-Based Transcranial Doppler Transducer and the Power Regulation of Its Detection System

    PubMed Central

    Yue, Qingwen; Liu, Dongxu; Wang, Wei; Di, Wenning; Lin, Di; Wang, Xi'an; Luo, Haosu

    2014-01-01

    Doppler sonographic measurement of flow velocity in the basal cerebral arteries through the intact skull was developed using a pulsed Doppler technique and 2 MHz emitting frequency. Relaxor-based ferroelectric single crystals Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) were chosen to be the piezoelectric transducer material due to their ultrahigh piezoelectric coefficients, high electromechanical coupling coefficients and low dielectric loss. The pulse-echo response of the transducer was measured using the conventional pulse-echo method in a water bath at room temperature. The −6 dB bandwidth of the transducer is 68.4% and the sensitivity is −17.4 dB. In order to get a good match between transducer and detection system, different transmission powers have been regulated by changing the impedance of the transmitting electric circuit. In the middle cerebral artery (MCA) measurement photograph results, as the transmission power is increasing, the detection results become clearer and clearer. A comparison at the same transmission power for different transducers shows that the detection photograph obtained by the crystal transducer was clearer than that obtained with a commercial transducer, which should make it easier for doctors to find the cerebral arteries. PMID:25536000

  19. Fabrication of a PMN-PT single crystal-based transcranial Doppler transducer and the power regulation of its detection system.

    PubMed

    Yue, Qingwen; Liu, Dongxu; Wang, Wei; Di, Wenning; Lin, Di; Wang, Xi'an; Luo, Haosu

    2014-12-19

    Doppler sonographic measurement of flow velocity in the basal cerebral arteries through the intact skull was developed using a pulsed Doppler technique and 2 MHz emitting frequency. Relaxor-based ferroelectric single crystals Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) were chosen to be the piezoelectric transducer material due to their ultrahigh piezoelectric coefficients, high electromechanical coupling coefficients and low dielectric loss. The pulse-echo response of the transducer was measured using the conventional pulse-echo method in a water bath at room temperature. The -6 dB bandwidth of the transducer is 68.4% and the sensitivity is -17.4 dB. In order to get a good match between transducer and detection system, different transmission powers have been regulated by changing the impedance of the transmitting electric circuit. In the middle cerebral artery (MCA) measurement photograph results, as the transmission power is increasing, the detection results become clearer and clearer. A comparison at the same transmission power for different transducers shows that the detection photograph obtained by the crystal transducer was clearer than that obtained with a commercial transducer, which should make it easier for doctors to find the cerebral arteries.

  20. Evaluation of a tailored injection profile (TIP) algorithm for uniform contrast-enhanced signal intensity profiles in MR angiography.

    PubMed

    Wilson, Gregory J; Maki, Jeffrey H

    2016-12-01

    To evaluate a contrast agent injection method that provides constant magnetic resonance imaging (MRI) signal intensity throughout a contrast-enhanced MR angiography acquisition. A tailored injection profile (TIP) algorithm was developed that used the signal intensity profile from a test bolus as an impulse response function, and predicted the response to various multiphasic injection profiles. Antecubital vein injections were administered via a commercially available multiphasic power injector. The TIP algorithm evaluated the predicted responses and selected the injection that best matched the desired (20-sec plateau) profile. Resulting signal intensity profiles from tailored and standard injection profiles were compared in 20 subjects (10 each). All subjects received a weight-based single-dose (0.1 mmol/kg) of gadoteridol, and abdominal aorta signal intensities were measured at 3T with a time-resolved, thick-slice, 3D spoiled-gradient-echo MR sequence with parameters approximating contrast-enhanced MR angiography. The single-phase, standard injection was injected at 1.6 mL/sec. Full-width at 80% maximum (FW80M) signal intensity was significantly longer for the tailored injection profiles (23.0 ± 2.2 vs. 9.0 ± 4.2 sec; P < 0.01). Concurrently, the profile peak signal intensity was reduced by 19% for the tailored profiles (12.0 ± 3.1 vs. 14.8 ± 2.8 times baseline; P = 0.058), nearly reaching significance. Multiphasic tailored injections from a power injector produced longer signal intensity profiles (156% increase in FW80M) with an accompanying decrease (19%) in peak signal intensity compared to a standard, single-phase injection. J. Magn. Reson. Imaging 2016. J. Magn. Reson. Imaging 2016;44:1664-1672. © 2016 International Society for Magnetic Resonance in Medicine.

  1. Dynamic Contrast-Enhanced Magnetic Resonance Enterography and Dynamic Contrast-Enhanced Ultrasonography in Crohn’s Disease: An Observational Comparison Study

    PubMed Central

    Wilkens, Rune; Peters, David A.; Nielsen, Agnete H.; Hovgaard, Valeriya P.; Glerup, Henning; Krogh, Klaus

    2017-01-01

    Purpose e Cross-sectional imaging methods are important for objective evaluationof small intestinal inflammationinCrohn’sdisease(CD).The primary aim was to compare relative parameters of intestinal perfusion between contrast-enhanced ultrasonography (CEUS) and dynamic contrast-enhanced magnetic resonance enterography (DCE-MRE) in CD. Furthermore, we aimed at testing the repeatability of regions of interest (ROIs) for CEUS. Methods This prospective study included 25 patients: 12 females (age: 37, range: 19–66) with moderate to severe CD and a bowel wall thickness>3mm evaluated with DCE-MRE and CEUS. CEUS bolus injection was performed twice for repeatability and analyzed in VueBox®. Correlations between modalities were described with Spearman’s rho, limits of agreement(LoA) and intraclass correlation coefficient(ICC). ROIrepeatability for CEUS was assessed. Results s The correlation between modalities was good and very good for bowel wall thickness (ICC=0.71, P<0.001) and length of the inflamed segment (ICC=0.89, P<0.001). Moderate-weak correlations were found for the time-intensity curve parameters: peak intensity (r=0.59, P=0.006), maximum wash-in-rate (r=0.62, P=0.004), and wash-in perfusion index (r=0.47, P=0.036). Best CEUS repeatability for peak enhancement was a mean difference of 0.73 dB (95% CI: 0.17 to 1.28, P=0.01) and 95% LoA from −3.8 to 5.3 dB. Good quality of curve fit improved LoA to −2.3 to 2.8 dB. Conclusion The relative perfusion of small intestinal CD assessed with DCE-MRE and CEUS shows only a moderate correlation. Applying strict criteria for ROIs is important and allows for good CEUS repeatability PMID:28286879

  2. Three-dimensional Contrast-enhanced Ultrasound in Response Assessment for Breast Cancer: A Comparison with Dynamic Contrast-enhanced Magnetic Resonance Imaging and Pathology

    PubMed Central

    Jia, Wan-Ru; Tang, Lei; Wang, Deng-Bin; Chai, Wei-Min; Fei, Xiao-Chun; He, Jian-Rong; Chen, Man; Wang, Wen-Ping

    2016-01-01

    To compare the capabilities of three-dimensional contrast enhanced ultrasound (3D-CEUS) and dynamic contrast-enhanced magnetic resonance (DCE-MRI) in predicting the response to neoadjuvant chemotherapy (NAC) among breast cancer patients, 48 patients with unilateral breast cancer were recruited for 3D-CEUS and DCE-MRI examinations both before and after NAC; pathology was used to validate the results. This study was approved by the institutional review board, and written informed consent was obtained from each patient. Imaging feature changes and pathological vascularity response, including microvessel density (MVD) and vascular endothelial growth factor (VEGF), were calculated. Pathological complete response (pCR) and major histological response (MHR) were used as references. The 3D-CEUS score, DCE-MRI score, MVD and VEGF significantly decreased (P < 0.0001) after NAC. The correlations between Δ3D-CEUS and ΔDCE-MRI with pCR (r = 0.649, P < 0.0001; r = 0.639, P < 0.0001) and MHR (r = 0.863, P < 0.0001; r = 0.836, P < 0.0001) were significant. All scores showed significant differences between the pCR and non-pCR groups with folder changes of 0.1, 0.1, 2.4, and 2.3, respectively (P = 0.0001, <0.0001, <0.0001 and <0.0001). In conclusion, 3D-CEUS is effective in assessing the response of breast cancer patients undergoing NAC. PMID:27652518

  3. A comparative study of contrast enhanced ultrasound and contrast enhanced magnetic resonance imaging for the detection and characterization of hepatic hemangiomas.

    PubMed

    Fang, Liang; Zhu, Zheng; Huang, Beijian; Ding, Hong; Mao, Feng; Li, Chaolun; Zeng, Mengsu; Zhou, Jianjun; Wang, Ling; Wang, Wenping; Chen, Yue

    2015-04-01

    This study aims to compare contrast enhanced ultrasound (CEUS) and contrast enhanced magnetic resonance imaging (CEMRI) for the detection and characterization of hepatic hemangiomas. Included in this retrospective study were 83 histopathologically confirmed lesions of hemangioma in 66 hospitalized patients who underwent both CEUS and CEMRI and received surgery. The enhancement patterns on CEUS and CEMRI in each lesion were compared and analyzed. In addition, data obtained by the two modalities were then compared with the pathological findings to determine their value in differential diagnosis of hepatic hemangiomas. CEUS diagnosed 78 lesions of hemangioma against 80 by CEMRI. There were no statistical significant differences in the diagnostic value between CEUS and CEMRI in terms of sensitivity (88.0% vs. 92.8%), specificity (99.0% vs. 99.4%), accuracy (97.3% vs. 98.4%), positive predictive value (93.6% vs. 96.3%), and negative predictive value (98.0% vs. 98.8%) (p > 0.05, all). In the arterial phase, the main enhancement pattern on both CEUS and CEMRI was peripheral nodular enhancement (73 vs. 76), but lesions with diffuse enhancement on CEUS outnumbered those on CEMRI (3 vs. 1) and lesions with circular enhancement on CEMRI outnumbered those on CEUS (3 vs. 2). In the portal venous phase and delayed phase, the main enhancement pattern was hyperechoic change on CEUS and hyperintense on CEMRI (66 vs. 65), some lesions presented isoechoic change (12 vs. 15). These results suggested CEUS, an equivalent to CEMRI, may have an added diagnostic value in hemangiomas.

  4. Comparison of gray-scale contrast-enhanced ultrasonography with contrast-enhanced computed tomography in different grading of blunt hepatic and splenic trauma: an animal experiment.

    PubMed

    Tang, Jie; Li, Wenxiu; Lv, Faqin; Zhang, Huiqin; Zhang, Lihai; Wang, Yuexiang; Li, Junlai; Yang, Li

    2009-04-01

    To compare the diagnostic value of contrast-enhanced ultrasonography (CEUS) with contrast-enhanced computed tomography (CECT) for the detection of different grading of solid organ injuries in blunt abdominal trauma in animals. A self-made miniature tools were used as models to simulate a blunt hepatic or splenic trauma in 16 and 14 anesthetized dogs, respectively. Baseline ultrasound, CEUS and CECT were used to detect traumatic injuries of livers and spleens. The degree of injuries was determined by CEUS according to the American Association for the Surgery of Trauma (AAST) scale and the results compared with injury scale based on CECT evaluation. CEUS showed 22 hepatic injury sites in 16 animals and 17 splenic injury sites in other 14 animals. According to AAST scale, 2 grade I, 4 grade II, 3 grade III, 5 grade IV and 2 grade V hepatic lesions were present in 16 animals; 2 grade I, 4 grade II, 6 grade III and 2 grade IV splenic lesions in 14 animals. On CECT scan, 21 hepatic and 17 splenic injuries were demonstrated. According to Becker CT scaling for hepatic injury, 1 grade I, 2 grade II, 4 grade III, 5 grade IV and 2 grade V hepatic injuries were present. On the basis of Buntain spleen scaling, 2 grade I, 5 grade II, 5 grade III, 2 grade IV splenic injuries were showed. After Spearman rank correlation analysis, the agreement of CEUS with CECT on the degree of hepatic and splenic injury is 93.3% and 92.9%, respectively. CT is currently considered as the reference method for grading blunt abdominal trauma, according to experiment results, CEUS grading showed high levels of concordance with CECT. CEUS can accurately determine the degree of injury and will play an important role in clinical application.

  5. Detectability of small blood vessels with high-frequency power Doppler and selection of wall filter cut-off velocity for microvascular imaging.

    PubMed

    Pinter, Stephen Z; Lacefield, James C

    2009-07-01

    Power Doppler imaging of physiologic and pathologic angiogenesis is widely used in preclinical studies to track normal development, disease progression and treatment efficacy but can be challenging given the presence of small blood vessels and slow flow velocities. Power Doppler images can be plagued with false-positive color pixels or undetected vessels, thereby complicating the interpretation of vascularity metrics such as color pixel density (CPD). As an initial step toward improved microvascular quantification, flow-phantom experiments were performed to establish relationships between vessel detection and various combinations of vessel size (160, 200, 250, 300 and 360 microm), flow velocity (4, 3, 2, 1 and 0.5 mm/s) and transducer frequency (30 and 40 MHz) while varying the wall filter cut-off velocity. Receiver operating characteristic (ROC) curves and areas under ROC curves indicate that good vessel detection performance can be achieved with a 40-MHz transducer for flow velocities > or =2 mm/s and with a 30-MHz transducer for flow velocities > or =1 mm/s. In the second part of the analysis, CPD was plotted as a function of wall filter cut-off velocity for each flow-phantom data set. Three distinct regions were observed: overestimation of CPD at low cut-offs, underestimation of CPD at high cut-offs and a plateau at intermediate cut-offs. The CPD at the plateau closely matched the phantom's vascular volume fraction and the length of the plateau corresponded with the flow-detection performance of the Doppler system assessed using ROC analysis. Color pixel density vs. wall filter cut-off curves from analogous in vivo experiments exhibited the same shape, including a distinct CPD plateau. The similar shape of the flow-phantom and in vivo curves suggests that the presence of a plateau in vivo can be used to identify the best-estimate CPD value that can be treated as a quantitative vascularity metric. The ability to identify the best CPD estimate is expected to

  6. Imaging of intracranial aneurysm by three-dimensional contrast enhanced duplex sonography-two case reports.

    PubMed

    Delcker; Turowski

    1997-12-01

    We report two cases of intracranial aneurysms to give an impression of the use of three-dimensional (3-D) transcranial duplex sonography in combination with the application of a transpulmonary stable contrast agent. Data acquisition was performed with a free-hand scanning of the transducer (2 MHz) and a prototype of a new magnetic sensor system to track the spatial orientation of the ultrasound probe while scanning the volume of interest. The 3-D data were stored and afterwards 3-D reconstructions performed. Three-dimensional transcranial color duplex system with power Doppler mode showed an exact spatial orientation of the intracranial arteries. The three-dimensional system lets the reader retrospectively choose the section plane through the 3-D data set, and the reconstructions through the data set allowed us to localize aneurysms in both cases. The increased freedom of movement of the transducer allows the sonographer to maintain transducer contact with the skin, while offering the freedom to move the transducer as needed to remain on the acoustic window. Copyright 1997 Elsevier Science Ireland Ltd.

  7. Performance of three-dimensional power Doppler angiography as third-step assessment in differential diagnosis of adnexal masses.

    PubMed

    Utrilla-Layna, J; Alcázar, J L; Aubá, M; Laparte, C; Olartecoechea, B; Errasti, T; Juez, L; Mínguez, J Á; Guerriero, S; Jurado, M

    2015-05-01

    To evaluate the contribution of three-dimensional (3D) power Doppler angiography (3D-PDA) to the differential diagnosis of adnexal masses. This was a prospective study in women diagnosed with a persistent adnexal mass and subsequently scheduled for surgery in a tertiary university hospital. All women were evaluated by transvaginal/transrectal ultrasound according to a predetermined three-step protocol, with transabdominal ultrasound being performed in some cases. First, morphological evaluation of the mass was performed using gray-scale 'pattern recognition' (first step). Lesions diagnosed as having a benign pattern were considered as being at low risk of malignancy whereas tumors with solid components, ascites and/or signs of carcinomatosis were considered as being at high risk of malignancy. In both cases no further test was performed and a decision regarding clinical management, either for follow-up or surgery, was taken. Tumors with solid components but without signs of ascites or carcinomatosis were considered as being at intermediate risk of malignancy. These lesions were assessed by two-dimensional (2D) PDA to evaluate tumor vascularity (color score) (second step). Solid tumors with a color score of 1 or 2 were considered as benign and no further test was performed, while tumors with a color score of 2, 3 or 4 within solid components or a color score of 3 or 4 in the case of a solid tumor were considered as malignant. The latter group underwent 3D-PDA assessment (third step). Vascularization index (VI) was calculated in a 1-mL sphere of the most vascularized area of the tumor. When a VI ≥ 24.015% was found, the tumor was considered as malignant. All masses were removed surgically and definitive histological diagnosis was used as the gold standard. Sensitivity and specificity for each strategy were calculated and compared. In the case of bilateral tumors, only the more suspicious one was used for analysis. A total of 367 adnexal masses diagnosed in 367

  8. Acute kidney injury after contrast-enhanced examination among elderly1

    PubMed Central

    Aoki, Beatriz Bonadio; Fram, Dayana; Taminato, Mônica; Batista, Ruth Ester Sayad; Belasco, Angélica; Barbosa, Dulce Aparecida

    2014-01-01

    OBJECTIVES: to assess renal function in elderly patients undergoing contrast-enhanced computed tomography and identify the preventive measures of acute kidney injury in the period before and after the examination. METHOD: longitudinal cohort study conducted at the Federal University of São Paulo Hospital, from March 2011 to March 2013. All hospitalized elderly, of both sexes, aged 60 years and above, who performed the examination, were included (n=93). We collected sociodemographic data, data related to the examination and to the care provided, and creatinine values prior and post exam. RESULTS: an alteration in renal function was observed in 51 patients (54%) with a statistically significant increase of creatinine values (p<0.04), and two patients (4.0%) required hemodialysis. CONCLUSION: There is an urgent need for protocols prior to and post contrast-enhanced examination in the elderly, and other studies to verify the prognosis of this population. PMID:25296148

  9. Brightness-preserving fuzzy contrast enhancement scheme for the detection and classification of diabetic retinopathy disease

    PubMed Central

    Datta, Niladri Sekhar; Dutta, Himadri Sekhar; Majumder, Koushik

    2016-01-01

    Abstract. The contrast enhancement of retinal image plays a vital role for the detection of microaneurysms (MAs), which are an early sign of diabetic retinopathy disease. A retinal image contrast enhancement method has been presented to improve the MA detection technique. The success rate on low-contrast noisy retinal image analysis shows the importance of the proposed method. Overall, 587 retinal input images are tested for performance analysis. The average sensitivity and specificity are obtained as 95.94% and 99.21%, respectively. The area under curve is found as 0.932 for the receiver operating characteristics analysis. The classifications of diabetic retinopathy disease are also performed here. The experimental results show that the overall MA detection method performs better than the current state-of-the-art MA detection algorithms. PMID:26870750

  10. Morphological image processing for quantitative shape analysis of biomedical structures: effective contrast enhancement.

    PubMed

    Kimori, Yoshitaka

    2013-11-01

    Image processing methods significantly contribute to visualization of images captured by biomedical modalities (such as mammography, X-ray computed tomography, magnetic resonance imaging, and light and electron microscopy). Quantitative interpretation of the deluge of complicated biomedical images, however, poses many research challenges, one of which is to enhance structural features that are scarcely perceptible to the human eye. This study introduces a contrast enhancement approach based on a new type of mathematical morphology called rotational morphological processing. The proposed method is applied to medical images for the enhancement of structural features. The effectiveness of the method is evaluated quantitatively by the contrast improvement ratio (CIR). The CIR of the proposed method is 12.1, versus 4.7 and 0.1 for two conventional contrast enhancement methods, clearly indicating the high contrasting capability of the method.

  11. Gadolinium-free MR in coarctation-can contrast-enhanced MR angiography be replaced?

    PubMed

    Kalmar, Peter I; Koestenberger, Martin; Marterer, Robert; Tschauner, Sebastian; Sorantin, Erich

    2016-01-01

    To determine the difference in vessel measurements, signal-to-noise ratio (SNR), and voxel size between contrast-enhanced and noncontrast magnetic resonance techniques in patients with coarctation of the aorta (CoA). In 39 patients, vessel size, SNR, and voxel size were compared in cine magnetic resonance imaging (MRI), gadolinium-free magnetic resonance angiography (Gd-free MRA), and contrast-enhanced MRA (ce-MRA). There was no significant difference in measurement and SNR, but there was a significant difference in voxel size (P<.001). Our results show that, in CoA patients, monitoring of vessel size using cine MRI and Gd-free MRA is equivalent to ce-MRA while being less invasive. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Optimum wavelet based masking for the contrast enhancement of medical images using enhanced cuckoo search algorithm.

    PubMed

    Daniel, Ebenezer; Anitha, J

    2016-04-01

    Unsharp masking techniques are a prominent approach in contrast enhancement. Generalized masking formulation has static scale value selection, which limits the gain of contrast. In this paper, we propose an Optimum Wavelet Based Masking (OWBM) using Enhanced Cuckoo Search Algorithm (ECSA) for the contrast improvement of medical images. The ECSA can automatically adjust the ratio of nest rebuilding, using genetic operators such as adaptive crossover and mutation. First, the proposed contrast enhancement approach is validated quantitatively using Brain Web and MIAS database images. Later, the conventional nest rebuilding of cuckoo search optimization is modified using Adaptive Rebuilding of Worst Nests (ARWN). Experimental results are analyzed using various performance matrices, and our OWBM shows improved results as compared with other reported literature.

  13. Current consensus and guidelines of contrast enhanced ultrasound for the characterization of focal liver lesions

    PubMed Central

    Jang, Jae Young; Kim, Moon Young; Jeong, Soung Won; Kim, Tae Yeob; Kim, Seung Up; Lee, Sae Hwan; Suk, Ki Tae; Park, Soo Young; Woo, Hyun Young; Kim, Sang Gyune; Heo, Jeong; Baik, Soon Koo; Kim, Hong Soo

    2013-01-01

    The application of ultrasound contrast agents (UCAs) is considered essential when evaluating focal liver lesions (FLLs) using ultrasonography (US). Microbubble UCAs are easy to use and robust; their use poses no risk of nephrotoxicity and requires no ionizing radiation. The unique features of contrast enhanced US (CEUS) are not only noninvasiveness but also real-time assessing of liver perfusion throughout the vascular phases. The later feature has led to dramatic improvement in the diagnostic accuracy of US for detection and characterization of FLLs as well as the guidance to therapeutic procedures and evaluation of response to treatment. This article describes the current consensus and guidelines for the use of UCAs for the FLLs that are commonly encountered in US. After a brief description of the bases of different CEUS techniques, contrast-enhancement patterns of different types of benign and malignant FLLs and other clinical applications are described and discussed on the basis of our experience and the literature data. PMID:23593604

  14. Three-dimensional contrast-enhanced magnetic resonance angiography of the thoracic vasculature.

    PubMed

    Leung, D A; Debatin, J F

    1997-01-01

    Magnetic resonance angiography (MRA) has become a useful non-invasive imaging technique for the assessment of vascular disease. Due to limitations such as respiratory motion artefacts, saturations problems, and long acquisition times, applications of MRA in the thorax have largely been restricted to imaging of the aorta. The recent introduction of breath-hold three-dimensional (3D) contrast-enhanced MRA promises not only to enhance conventional MR protocols for aortic imaging, but to extend the clinical indications of MRI to diseases affecting other vascular structures of the thorax, most notably the pulmonary arteries. This article describes the technical aspects of contrast-enhanced 3D MRA and reviews existing and potential future clinical applications.

  15. Feature and contrast enhancement of mammographic image based on multiscale analysis and morphology.

    PubMed

    Wu, Shibin; Yu, Shaode; Yang, Yuhan; Xie, Yaoqin

    2013-01-01

    A new algorithm for feature and contrast enhancement of mammographic images is proposed in this paper. The approach bases on multiscale transform and mathematical morphology. First of all, the Laplacian Gaussian pyramid operator is applied to transform the mammography into different scale subband images. In addition, the detail or high frequency subimages are equalized by contrast limited adaptive histogram equalization (CLAHE) and low-pass subimages are processed by mathematical morphology. Finally, the enhanced image of feature and contrast is reconstructed from the Laplacian Gaussian pyramid coefficients modified at one or more levels by contrast limited adaptive histogram equalization and mathematical morphology, respectively. The enhanced image is processed by global nonlinear operator. The experimental results show that the presented algorithm is effective for feature and contrast enhancement of mammogram. The performance evaluation of the proposed algorithm is measured by contrast evaluation criterion for image, signal-noise-ratio (SNR), and contrast improvement index (CII).

  16. Feature and Contrast Enhancement of Mammographic Image Based on Multiscale Analysis and Morphology

    PubMed Central

    Wu, Shibin; Xie, Yaoqin

    2013-01-01

    A new algorithm for feature and contrast enhancement of mammographic images is proposed in this paper. The approach bases on multiscale transform and mathematical morphology. First of all, the Laplacian Gaussian pyramid operator is applied to transform the mammography into different scale subband images. In addition, the detail or high frequency subimages are equalized by contrast limited adaptive histogram equalization (CLAHE) and low-pass subimages are processed by mathematical morphology. Finally, the enhanced image of feature and contrast is reconstructed from the Laplacian Gaussian pyramid coefficients modified at one or more levels by contrast limited adaptive histogram equalization and mathematical morphology, respectively. The enhanced image is processed by global nonlinear operator. The experimental results show that the presented algorithm is effective for feature and contrast enhancement of mammogram. The performance evaluation of the proposed algorithm is measured by contrast evaluation criterion for image, signal-noise-ratio (SNR), and contrast improvement index (CII). PMID:24416072

  17. CW-THz image contrast enhancement using wavelet transform and Retinex

    NASA Astrophysics Data System (ADS)

    Chen, Lin; Zhang, Min; Hu, Qi-fan; Huang, Ying-Xue; Liang, Hua-Wei

    2015-10-01

    To enhance continuous wave terahertz (CW-THz) scanning images contrast and denoising, a method based on wavelet transform and Retinex theory was proposed. In this paper, the factors affecting the quality of CW-THz images were analysed. Second, an approach of combination of the discrete wavelet transform (DWT) and a designed nonlinear function in wavelet domain for the purpose of contrast enhancing was applied. Then, we combine the Retinex algorithm for further contrast enhancement. To evaluate the effectiveness of the proposed method in qualitative and quantitative, it was compared with the adaptive histogram equalization method, the homomorphic filtering method and the SSR(Single-Scale-Retinex) method. Experimental results demonstrated that the presented algorithm can effectively enhance the contrast of CW-THZ image and obtain better visual effect.

  18. Preparation of Magnetite Nanoemulsion Stabilized by Tween 81 for MRI Contrast Enhancement

    NASA Astrophysics Data System (ADS)

    Nikolaev, Boris P.; Eliseev, Oleg V.; Marchenko, Yaroslav Yu.; Yakovleva, Liudmila Yu.; Zimina, Tatiana M.; Soloviev, Alexei V.; Luchinin, Victor V.

    2010-12-01

    Magnetite nanoemulsions (NE) were synthesized via procedure of heterophase synthesis in a ternary system: Tween 81/pentadecane/water. Prepared NEs were studied by dynamic light scattering and NMR spectroscopy. Their size was of the order of 10 nm and they revealed superparamagnetic properties. MRI efficiency of the NEs was demonstrated by measuring magnetic spin-spin relaxation rates, which complied with the properties of negative contrast agents. MRI of agar phantom demonstrates high grade of contrast enhancement in vitro. Toxicity of the preparations was studied on murine model. Studies revealed no signs of acute or short-term (within 30 days) toxicity in mice. Synthesized magnetite NEs have potential for in vivo MRI contrast enhancement applications.

  19. Visualisation of contrast-enhanced intraoperative optical coherence tomography with indocyanine green.

    PubMed

    Ehlers, Justis P; McNutt, Stephen; Dar, Suhail; Tao, Yuankai K; Srivastava, Sunil K

    2014-11-01

    Optical coherence tomography (OCT)-based visualisation of ophthalmic anatomy has transformed the clinical practice of ophthalmology. The translation of OCT into the surgical theatre is currently being actively researched and may provide a paradigm shift in surgical practice. Enhanced visualisation of tissues and tissue planes may provide further iterative improvement in surgeon feedback. Contrast-enhanced intraoperative OCT (iOCT) has been previously described with triamcinolone. In this report, we describe the OCT features and contrast enhancement noted with indocyanine green using iOCT in human subjects as well as an ex vivo analysis in porcine eyes. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  20. Automatic Contrast Enhancement of Brain MR Images Using Hierarchical Correlation Histogram Analysis.

    PubMed

    Chen, Chiao-Min; Chen, Chih-Cheng; Wu, Ming-Chi; Horng, Gwoboa; Wu, Hsien-Chu; Hsueh, Shih-Hua; Ho, His-Yun

    Parkinson's disease is a progressive neurodegenerative disorder that has a higher probability of occurrence in middle-aged and older adults than in the young. With the use of a computer-aided diagnosis (CAD) system, abnormal cell regions can be identified, and this identification can help medical personnel to evaluate the chance of disease. This study proposes a hierarchical correlation histogram analysis based on the grayscale distribution degree of pixel intensity by constructing a correlation histogram, that can improves the adaptive contrast enhancement for specific objects. The proposed method produces significant results during contrast enhancement preprocessing and facilitates subsequent CAD processes, thereby reducing recognition time and improving accuracy. The experimental results show that the proposed method is superior to existing methods by using two estimation image quantitative methods of PSNR and average gradient values. Furthermore, the edge information pertaining to specific cells can effectively increase the accuracy of the results.

  1. Digital contrast enhancement of (18)Fluorine-fluorodeoxyglucose positron emission tomography images in hepatocellular carcinoma.

    PubMed

    Pandey, Anil Kumar; Sharma, Sanjay Kumar; Agarwal, Krishan Kant; Sharma, Punit; Bal, Chandrasekhar; Kumar, Rakesh

    2016-01-01

    The role of (18)fluorodeoxyglucose positron emission tomography (PET) is limited for detection of primary hepatocellular carcinoma (HCC) due to low contrast to the tumor, and normal hepatocytes (background). The aim of the present study was to improve the contrast between the tumor and background by standardizing the input parameters of a digital contrast enhancement technique. A transverse slice of PET image was adjusted for the best possible contrast, and saved in JPEG 2000 format. We processed this image with a contrast enhancement technique using 847 possible combinations of input parameters (threshold "m" and slope "e"). The input parameters which resulted in an image having a high value of 2(nd) order entropy, and edge content, and low value of absolute mean brightness error, and saturation evaluation metrics, were considered as standardized input parameters. The same process was repeated for total nine PET-computed tomography studies, thus analyzing 7623 images. The selected digital contrast enhancement technique increased the contrast between the HCC tumor and background. In seven out of nine images, the standardized input parameters "m" had values between 150 and 160, and for other two images values were 138 and 175, respectively. The value of slope "e" was 4 in 4 images, 3 in 3 images and 1 in 2 images. It was found that it is important to optimize the input parameters for the best possible contrast for each image; a particular value was not sufficient for all the HCC images. The use of above digital contrast enhancement technique improves the tumor to background ratio in PET images of HCC and appears to be useful. Further clinical validation of this finding is warranted.

  2. Hydrogen atom donor compounds as contrast enhancers for black-and-white photothermographic and thermographic elements

    DOEpatents

    Harring, Lori S.; Simpson, Sharon M.; Sansbury, Francis H.

    1997-01-01

    Hydrogen atom donor compounds are useful as contrast enhancers when used in combination with (i) hindered phenol developers, and (ii) trityl hydrazide and/or formyl-phenyl hydrazine co-developers, to produce ultra-high contrast black-and-white photothermographic and thermographic elements. The photothermographic and thermographic elements may be used as a photomask in a process where there is a subsequent exposure of an ultraviolet or short wavelength visible radiation-sensitive imageable medium.

  3. Evaluation of the potential utility of flat panel CT for quantifying relative contrast enhancement

    SciTech Connect

    Jones, A. Kyle; Mahvash, Armeen

    2012-07-15

    Purpose: Certain directed oncologic therapies seek to take advantage of the fact that tumors are typically more susceptible to directed therapeutic agents than normal tissue owing to their extensive networks of poorly formed, leaky vasculature. If differences between the vascularity of normal and tumor tissues could be quantified, patients could be selected for or excluded from directed treatments on the basis of this difference. However, angiographic imaging techniques such as digital subtraction angiography (DSA) yield two-dimensional data that may be inadequate for this task. As a first step, the authors evaluated the feasibility of using a commercial implementation of flat panel computed tomography (FPCT) to quantify differences in enhancement of a simulated tumor compared with normal tissue based on differences in CT number measured in precontrast and postcontrast scans. Methods: To evaluate the FPCT scanner studied, the authors scanned several phantoms containing simulated normal and tumor tissues. In the first experiment, the authors used an anthropomorphic phantom containing inclusions representing normal, tumor, and bone tissue to evaluate the constancy of CT numbers in scans repeated at clinically relevant intervals of 1 and 3 min. The authors then scanned gelatin phantoms containing dilutions of iodinated contrast to evaluate the accuracy of relative contrast enhancement measurements for a clinical FPCT system. Data were analyzed using widely available software. Results: CT numbers measured in identical locations were constant over both scan intervals evaluated. Measured relative contrast enhancement values were accurate compared with known relative contrast enhancement values. Care must be taken to avoid artifacts in reconstructed images when placing regions of interest. Conclusions: Despite its limitations, FPCT in the interventional laboratory can be used to quantify relative contrast enhancement in phantoms. This is accomplished by measuring CT

  4. On the Dark Rim Artifact in Dynamic Contrast-Enhanced MRI Myocardial Perfusion Studies

    PubMed Central

    Di Bella, E.V.R.; Parker, D.L.; Sinusas, A.J.

    2008-01-01

    A dark band or rim along parts of the subendocardial border of the left ventricle (LV) and the myocardium has been noticed in some dynamic contrast-enhanced MR perfusion studies. The artifact is thought to be due to susceptibility effects from the gadolinium bolus, motion, or resolution, or a combination of these. Here motionless ex vivo hearts in which the cavity was filled with gadolinium are used to show that dark rim artifacts can be consistent with resolution effects alone. PMID:16200553

  5. High Resolution X-Ray Phase Contrast Imaging With Acoustic Tissue-Selective Contrast Enhancement

    DTIC Science & Technology

    2006-06-01

    microfocus x - ray source. Rev. Sci. Instr. 68, 2774 (1997). 8. Krol, A. et al. Laser-based microfocused x - ray source for mammography: Feasibility study...W81XWH-04-1-0481 TITLE: High Resolution X - ray Phase Contrast Imaging With Acoustic Tissue-Selective Contrast Enhancement PRINCIPAL...REPORT TYPE Annual 3. DATES COVERED (From - To) 1 Jun 2005 – 31 May 2006 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER High Resolution X - ray

  6. Contrast-enhanced ultrasonographic characteristics of adrenal glands in dogs with pituitary-dependent hyperadrenocorticism.

    PubMed

    Bargellini, Paolo; Orlandi, Riccardo; Paloni, Chiara; Rubini, Giuseppe; Fonti, Paolo; Peterson, Mark E; Boiti, Cristiano

    2013-01-01

    A noninvasive method for quantifying adrenal gland vascular patterns could be helpful for improving detection of adrenal gland disease in dogs. The purpose of this retrospective study was to compare the contrast-enhanced ultrasound (CEUS) characteristics of adrenal glands in 18 dogs with pituitary-dependent hyperadrenocorticism (PDH) vs. four clinically healthy dogs. Each dog received a bolus of the contrast agent (SonoVue®, 0.03 ml/kg of body weight) into the cephalic vein, immediately followed by a 5 ml saline flush. Dynamic contrast enhancement was analyzed using time-intensity curves in two regions of interest drawn manually in the caudal part of the adrenal cortex and medulla, respectively. In healthy dogs, contrast enhancement distribution was homogeneous and exhibited increased intensity from the medulla to the cortex. In the washout phase, there was a gradual and homogeneous decrease of enhancement of the adrenal gland. For all dogs with PDH, there was rapid, chaotic, and simultaneous contrast enhancement in both the medulla and cortex. Three distinct perfusion patterns were observed. Peak perfusion intensity was approximately twice as high (P < 0.05) in dogs with PDH compared with that of healthy dogs (28.90 ± 10.36 vs. 48.47 ± 15.28, respectively). In dogs with PDH, adrenal blood flow and blood volume values were approximately two- to fourfold (P < 0.05) greater than those of controls. Findings from the present study support the use of CEUS as a clinical tool for characterizing canine adrenal gland disease based on changes in vascular patterns. © 2013 Veterinary Radiology & Ultrasound.

  7. Contrast-Enhanced Abdominal MRI for Suspected Appendicitis: How We Do It

    PubMed Central

    Kinner, Sonja; Repplinger, Michael D.; Pickhardt, Perry J.; Reeder, Scott B.

    2017-01-01

    OBJECTIVE The purpose of this article is to describe our approach to contrast-enhanced abdominal MRI in patients with nontraumatic abdominal pain and suspected appendicitis. We aim to share our experience on the advantages, pearls, and pitfalls of MRI in this clinical setting, in comparison with CT and ultrasound. CONCLUSION We present some typical cases of appendicitis and alternative diagnoses in patients presenting with acute nontraumatic abdominal pain. PMID:27065072

  8. Soft-Tissue Tumor Contrast Enhancement Patterns: Diagnostic Value and Comparison Between Ultrasound and MRI.

    PubMed

    Gruber, Leonhard; Loizides, Alexander; Luger, Anna K; Glodny, Bernhard; Moser, Patrizia; Henninger, Benjamin; Gruber, Hannes

    2017-02-01

    The purpose of this study was to assess and compare contrast-enhanced ultrasound and MRI patterns in the diagnosis of soft-tissue masses. Two hundred fifty-five consecutively registered patients with histologically confirmed soft-tissue masses were included in this retrospective study. The diagnostic properties of four predefined contrast enhancement (CE) patterns were assessed, and logistic regression analysis was performed to determine the correlation between diagnosis and CE pattern, lesion size, and patient age and sex. The influence of lesion size on the occurrence of inhomogeneous CE patterns in malignancies was also determined. Homogeneous CE patterns were highly specific for benignity, and inhomogeneous CE was moderately specific for malignancy in both ultrasound and MRI. A combination of homogeneous and inhomogeneous CE patterns led to 88.3% and 88.7% sensitivity, 66.7% and 59.7% specificity, 73.4% and 68.2% correct classification, 54.6% and 47.8% positive predictive value, 92.6% and 92.7% negative predictive value, 2.65 and 2.20 positive likelihood ratio, and 0.18 and 0.19 negative likelihood ratio for contrast-enhanced ultrasound and contrast-enhanced MRI. Cases with homogeneous CE in either ultrasound or MRI also were predominantly benign. The occurrence of inhomogeneous CE in malignant lesions increased with size. CE patterns in ultrasound and MRI offer additional information about the differentiation of an unknown soft-tissue mass. The results of this study showed that homogeneous or absent CE was specific for benign differentiation and that heterogeneous CE was linked to malignancy. The routine analysis of CE patterns should increase diagnostic reliability in unclear soft-tissue masses.

  9. An Interventional MRI Technique for the Molecular Characterization of Heterogeneous Intra-Prostatic Dynamic Contrast Enhancement

    DTIC Science & Technology

    2004-10-01

    angiogenesis. Here we demonstrate the feasibility of precisely co-localizing DCE-MRI data with the genomic and proteomic profiles of underlying biopsy tissue...using a novel MRI-guided biopsy technique in a patient with prostate cancer. Abbreviations: DCE-MRI – Dynamic Contrast Enhanced Magnetic...to provide more complete information on a tumor’s microvascular biology, in contrast to information obtained from a biopsy , which may be subject to

  10. Gray scale and contrast-enhanced ultrasound imaging of malignant liver tumors of vascular origin

    PubMed Central

    Schweitzer, Nora; Soudah, Bisharah; Gebel, Michael; Manns, Michael Peter

    2015-01-01

    Objectives Malignant vascular tumors of the liver are rare. The aim of this study was to investigate the applicability of gray scale and contrast-enhanced ultrasonography in patients with epithelioid hemangioendothelioma (EHE) of the liver and hepatic angiosarcoma (HA) and to describe the clinical presentation. Methods We retrospectively analyzed all patients with epithelioid hemangioendothelioma or hemangiosarcoma of the liver from 1998 to 2011, who underwent ultrasound investigation. We describe the findings in gray scale and contrast-enhanced ultrasound and the clinical course of the disease of seven patients with EHE and five patients with HA. Results Ultrasound investigation in EHE showed mostly multiple hypoechoic irregular lesions close to the liver capsule and with a halo in some cases. Contrast enhancement revealed inhomogeneously and through all contrast phases vascularized tumors with a rim enhancement in 50%, with or without early wash out. All tumors had avascular parts. HA presented as multiple and irregular hypo-, iso- or hyperechoic lesions. After contrast enhancement, hypervascularization with individual patterns was evident in all patients. Of five, three had liquid parts. Patients with HA were significantly older (58 vs. 37 years, p = 0.014) and presented with lower thrombocyte counts (84 vs. 264, p = 0.0025) and with higher CEA levels (4.6 vs. 1.5, p = 0.03). Conclusion EHE and HA are inhomogeneous tumors, explaining the high inter-individual variability and heterogeneity in ultrasound examination. The presence of multifocal lesions, heterogeneity and undefined margins may differentiate EHE or HA from hemangioma. A biopsy is essential in the diagnosis of vascular tumors. PMID:25653860

  11. Gadolinium Contrast Enhancement Improves Confidence in Diagnosing Recurrent Soft Tissue Sarcoma by MRI.

    PubMed

    Chou, Shinn-Huey S; Hippe, Daniel S; Lee, Amie Y; Scherer, Kurt; Porrino, Jack A; Davidson, Darin J; Chew, Felix S; Ha, Alice S

    2017-05-01

    To determine how utilization of postgadolinium magnetic resonance imaging (MRI) influenced reader accuracy and confidence at identifying postoperative soft tissue sarcoma (STS) recurrence among readers with various levels of expertise. This retrospective study was institutional review board approved and Health Insurance Portability and Accountability Act compliant. Postoperative MRI from 26 patients with prior STS resection (13 patients with confirmed recurrence, 13 without recurrence) was reviewed. Four blinded readers of varying expertise (radiology resident, fellow, attending, and orthopedic oncologist) initially evaluated only the precontrast images and rated each MRI for recurrence on a 5-point confidence scale. Assessment was repeated with the addition of contrast-enhanced sequences. Diagnostic accuracy based on confidence ratings was evaluated using the area under the receiver operating characteristic curve (AUC). Changes in confidence ratings were calculated using Wilcoxon signed-rank test. All readers demonstrated good diagnostic accuracy both with and without contrast-enhanced images (AUC >0.98 for each reader). When contrast-enhanced images were made available, the resident recorded improved confidence with both assigning (P = 0.031) and excluding recurrence (P = 0.006); the fellow showed improved confidence only with assigning recurrence (P = 0.015); and the surgeon showed improved confidence in excluding recurrence (P = 0.003). The addition of contrast-enhanced images did not significantly influence the diagnostic confidence of the attending radiologist. Diagnostic accuracy of MRI was excellent in evaluating postoperative STS recurrence, and reader confidence improved depending on expertise when postgadolinium imaging was included in the assessment. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  12. Application of FLASH-3D dynamic contrast-enhanced imaging for diagnosis of endometrial carcinoma.

    PubMed

    Du, Lixin; Li, Xiaohu; Qiu, Xixiong; Liu, Xiaolei; Wang, Yuli; Yu, Yongqiang

    2016-10-01

    To investigate the application and value of fast low-angle shot three-dimensional (FLASH-3D) dynamic contrast-enhanced MRI for the pre-operative staging of endometrial carcinoma. This prospective study enrolled 48 patients with complete clinical data and pathologically confirmed endometrial carcinoma from July 2012 to March 2014. After routine MRI examination, subjects underwent FLASH-3D dynamic contrast-enhanced examination. The dynamically enhanced features of the uterine wall and tumours were analyzed. FLASH-3D pre-operative staging and findings in relation to myometrial invasion were compared with post-operative pathological results in a double-blind manner. There were 48 cases of pathologically proven endometrial carcinoma, including 34 patients with Stage I (Stage Ia 22 cases and Stage Ib 12 cases), 9 with Stage II, 3 with Stage III and 2 with Stage IV. The staging accuracy for endometrial carcinoma was 81% (39/48) using FLASH-3D dynamic contrast-enhanced sequences. The sensitivity, specificity and accuracy for the determination of deep myometrial invasion were 84%, 90% and 88%, respectively. There was no significant difference compared with the results of post-operative pathology (p > 0.05). FLASH-3D dynamic contrast-enhanced imaging may be valuable for the early diagnosis and pre-operative staging of endometrial carcinoma. Its high accuracy for assessing deep myometrial invasion makes FLASH-3D imaging an important tool for selecting the optimal therapeutic protocol and for prognosis estimation. FLASH-3D can significantly improve the accurate assessment of the depth of tumour invasion into the myometrium and may thus help to guide clinical surgical choices and post-operative evaluation. FLASH-3D is thus a promising technique for the routine examination of female pelvic tumours.

  13. Digital contrast enhancement of 18Fluorine-fluorodeoxyglucose positron emission tomography images in hepatocellular carcinoma

    PubMed Central

    Pandey, Anil Kumar; Sharma, Sanjay Kumar; Agarwal, Krishan Kant; Sharma, Punit; Bal, Chandrasekhar; Kumar, Rakesh

    2016-01-01

    Purpose: The role of 18fluorodeoxyglucose positron emission tomography (PET) is limited for detection of primary hepatocellular carcinoma (HCC) due to low contrast to the tumor, and normal hepatocytes (background). The aim of the present study was to improve the contrast between the tumor and background by standardizing the input parameters of a digital contrast enhancement technique. Materials and Methods: A transverse slice of PET image was adjusted for the best possible contrast, and saved in JPEG 2000 format. We processed this image with a contrast enhancement technique using 847 possible combinations of input parameters (threshold “m” and slope “e”). The input parameters which resulted in an image having a high value of 2nd order entropy, and edge content, and low value of absolute mean brightness error, and saturation evaluation metrics, were considered as standardized input parameters. The same process was repeated for total nine PET-computed tomography studies, thus analyzing 7623 images. Results: The selected digital contrast enhancement technique increased the contrast between the HCC tumor and background. In seven out of nine images, the standardized input parameters “m” had values between 150 and 160, and for other two images values were 138 and 175, respectively. The value of slope “e” was 4 in 4 images, 3 in 3 images and 1 in 2 images. It was found that it is important to optimize the input parameters for the best possible contrast for each image; a particular value was not sufficient for all the HCC images. Conclusion: The use of above digital contrast enhancement technique improves the tumor to background ratio in PET images of HCC and appears to be useful. Further clinical validation of this finding is warranted. PMID:26917889

  14. Counterclockwise barber-pole sign on prenatal three-dimensional power Doppler sonography in a case of duodenal obstruction without intestinal malrotation.

    PubMed

    Hsu, Chin-Yuan; Chiba, Yoshihide; Fukui, On; Sasaki, Yoshihito; Miyashita, Susumu

    2004-02-01

    Three-dimensional (3D) power Doppler sonographic imaging provides a 3D view of the blood vessels. This technique reportedly has advantages over other forms of sonography in visualizing normal and abnormal fetal vascular anatomy. We report the case of a 36-year-old pregnant woman in whom 3D power Doppler sonography with simultaneous gray-scale imaging was performed at 32 weeks' gestational age to investigate an intestinal obstruction in the fetus that was suspected on the basis of 2-dimensional sonographic findings. The 3D sonograms revealed that the superior mesenteric artery and vein of the fetus were wound counterclockwise, forming the "barber-pole" sign. At 38 weeks' menstrual age, the female infant was delivered vaginally. Only duodenal atresia and annular pancreas, but not intestinal malrotation, were found postnatally. Surgical reconstruction of the duodenum was performed, with no major complications. Previous research suggests that the counterclockwise barber-pole sign is a normal finding. On the basis of our case, we believe that this "negative finding" might be used to exclude the diagnosis of midgut volvulus, a condition that would be expected to cause these vessels to wrap around in a clockwise direction.

  15. DVP parametric imaging for characterizing ovarian masses in contrast-enhanced ultrasound.

    PubMed

    Sha-sha, H; Li, H; Jie, M; Gui, F; Wen-jun, G; Ming, H; Yang, Z; Qing, Y

    2015-01-01

    To evaluate whether parametric imaging with contrast-enhanced ultrasound is an approach capable of for the differential diagnosis of ovarian masses. The authors analysed 50 cases of ovarian masses by routine ultrasound and contrast-enhanced ultrasound with a new dedicated parametric image processing software-Sonoliver. The angiogenesis and blood perfusion mode on a digital video recorder were recorded and the morphological characteristics of time-intensity curve (TIC) and dynamic vascular pattern (DVP) curve were subsequently described. The quantity factor, including time to peak (TTP), maximum intensity (IMAX), rise time, (RT), mean transit time (mTT), generated by Sonoliver software were compared in both histological gradings. There were 24 cases (86%) displaying mainly hypo-enhanced with blue imaging in those with benign masses and 15 cases (68%) displaying mainly hyper-enhanced imaging with red in those with malignant masses. The difference was statistically significant (p < 0.05). DVP curves were unipolar below the baseline in 23 cases (82%) of benign masses and unipolar above the baseline in 15 cases (68%) of malignant masses. IMAX, TTP, and mTT were all significantly higher in those with malignant masses than those with benign ones (all p < 0.05), but, no statistical difference in the RT between the two groups was found (p > 0.05). According to the results, DVP parametric imaging is a new approach capable of differential diagnoses of overian masses with contrast-enhanced ultrasound.

  16. Non-contrast-enhanced renal and abdominal MR angiography using velocity-selective inversion preparation.

    PubMed

    Shin, Taehoon; Worters, Pauline W; Hu, Bob S; Nishimura, Dwight G

    2013-05-01

    Non-contrast-enhanced MR angiography is a promising alternative to the established contrast-enhanced approach as it reduces patient discomfort and examination costs and avoids the risk of nephrogenic systemic fibrosis. Inflow-sensitive slab-selective inversion recovery imaging has been used with great promise, particularly for abdominal applications, but has limited craniocaudal coverage due to inflow time constraints. In this work, a new non-contrast-enhanced MR angiography method using velocity-selective inversion preparation is developed and applied to renal and abdominal angiography. Based on the excitation k-space formalism and Shinnar-Le-Roux transform, a velocity-selective excitation pulse is designed that inverts stationary tissues and venous blood while preserving inferiorly flowing arterial blood. As the magnetization of the arterial blood in the abdominal aorta and iliac arteries is well preserved during the magnetization preparation, artery visualization over a large abdominal field of view is achievable with an inversion delay time that is chosen for optimal background suppression. Healthy volunteer tests demonstrate that the proposed method significantly increases the extent of visible arteries compared with the slab-selective approach, covering renal arteries through iliac arteries over a craniocaudal field of view of 340 mm. Copyright © 2012 Wiley Periodicals, Inc.

  17. Non-contrast-enhanced Peripheral Angiography Using a Sliding Interleaved Cylinder Acquisition

    PubMed Central

    Kwon, Kie Tae; Kerr, Adam B.; Wu, Holden H.; Hu, Bob S.; Brittain, Jean H.; Nishimura, Dwight G.

    2014-01-01

    Purpose To develop a new sequence for non-contrast-enhanced peripheral angiography using a sliding interleaved cylinder (SLINCYL) acquisition. Methods A venous saturation pulse was incorporated into a 3D magnetization-prepared balanced steady-state free precession sequence for non-contrast-enhanced peripheral angiography to improve artery-vein contrast. The SLINCYL acquisition, which consists of a series of overlapped thin slabs for volumetric coverage similar to the original sliding interleaved ky (SLINKY) acquisition, was employed to evenly distribute the venous-suppression effects over the FOV. In addition, the thin-slab-scan nature of SLINCYL and the centric-ordered sampling geometry of its readout trajectory were exploited to implement efficient fluid-suppression and parallel imaging approaches. The sequence was tested in healthy subjects and a patient. Results Compared to a multiple overlapped thin slab acquisition, both SLINKY and SLINCYL suppressed the venetian blind artifacts and provided similar artery-vein contrast. However, SLINCYL achieved this with shorter scan times and less noticeable artifacts from k-space amplitude modulation than SLINKY. The fluid-suppression and parallel imaging schemes were also validated. A patient study using the SLINCYL-based sequence well identified stenoses at the super cial femoral arteries, which were also confirmed with digital subtraction angiography. Conclusion Non-contrast-enhanced angiography using SLINCYL can provide angiograms with improved artery-vein contrast in the lower extremities. PMID:25203505

  18. Selective X-ray contrast enhancement of the spleen of living mice mediated by gold nanorods.

    PubMed

    Wathen, Connor A; Caldwell, Chuck; Chanda, Nripen; Upendran, Anandhi; Zambre, Ajit; Afrasiabi, Zahra; Chapaman, Sarah E; Foje, Nathan; Leevy, W Matthew; Kannan, Raghuraman

    2015-01-01

    Gold nanomaterials (AuNPs) represent a promising new class of contrast agents for X-ray computed tomographic (CT) imaging in both research and clinical settings. These materials exhibit superior X-ray absorption properties compared with other iodinated agents, and thus require lower injection doses. Gold is nonimmunogenic and therefore contributes to safety profile in living specimens. Unfortunately, most reports on the use of AuNPs as X-ray CT enhancers only demonstrate marginal enhancement of the intended anatomical structure. In this study, we demonstrate the dramatic properties of gold nanorods (GNR) to serve as robust X-ray CT contrast-enhancing agent for selective imaging of the spleen. These organ-specific uptake properties were delineated by performing longitudinal CT imaging of living mice that were dosed with GNR at 2 day intervals. Rapid uptake in spleen was noted within 12 h of first systemic administration with a change in contrast enhancement of 90 Hounsfield units (ΔHU = 90) and with two subsequent injections a total contrast enhancement of over 200 HU was observed. The resulting images provide excellent contrast that will enable the detailed anatomical visualization and study of a range of pre-clinical models of spleen disease including infection and cancer. Copyright © 2014 John Wiley & Sons, Ltd.

  19. Contrast-Enhanced Magnetic Resonance Imaging in Pediatric Patients: Review and Recommendations for Current Practice

    PubMed Central

    Bhargava, Ravi; Hahn, Gabriele; Hirsch, Wolfgang; Kim, Myung-Joon; Mentzel, Hans-Joachim; Olsen, Øystein E.; Stokland, Eira; Triulzi, Fabio; Vazquez, Elida

    2013-01-01

    Magnetic resonance imaging (MRI), frequently with contrast enhancement, is the preferred imaging modality for many indications in children. Practice varies widely between centers, reflecting the rapid pace of change and the need for further research. Guide-line changes, for example on contrast-medium choice, require continued practice reappraisal. This article reviews recent developments in pediatric contrast-enhanced MRI and offers recommendations on current best practice. Nine leading pediatric radiologists from internationally recognized radiology centers convened at a consensus meeting in Bordeaux, France, to discuss applications of contrast-enhanced MRI across a range of indications in children. Review of the literature indicated that few published data provide guidance on best practice in pediatric MRI. Discussion among the experts concluded that MRI is preferred over ionizing-radiation modalities for many indications, with advantages in safety and efficacy. Awareness of age-specific adaptations in MRI technique can optimize image quality. Gadolinium-based contrast media are recommended for enhancing imaging quality. The choice of most appropriate contrast medium should be based on criteria of safety, tolerability, and efficacy, characterized in age-specific clinical trials and personal experience. PMID:25114547

  20. Adrenal glands in hypovolemic shock: preservation of contrast enhancement at dynamic computed tomography.

    PubMed

    Ito, Katsuyoshi; Higashi, Hiroki; Kanki, Akihiko; Tamada, Tsutomu; Yamashita, Takenori; Yamamoto, Akira; Watanabe, Shigeru

    2010-07-01

    To evaluate contrast enhancement effects of the adrenal glands at dynamic computed tomography (CT) in adult severe trauma patients with hypovolemic shock in comparison with patients without hypovolemic shock. This study population included a total of 74 patients with (n = 24) and without (n = 50) blunt trauma and hypovolemic shock. Measurement of CT attenuation values of the adrenal gland and calculation of the enhancement washout percentages were performed. The mean +/- SD CT attenuation values of the adrenal glands in the arterial phase of dynamic CT in patients with hypovolemic shock (137.3 +/- 41.7 Hounsfield unit [HU]) were not significantly different (P = 0.16) from those in control subjects (127.3 +/- 19.6 HU). The mean CT attenuation values of the adrenal glands in the delayed phase of dynamic CT in patients with hypovolemic shock (82.0 +/- 14.7 HU) were also not significantly different (P = 0.89) from those in control subjects (82.4 +/- 10.0 HU). The mean percentage (35%) of enhancement washout of the adrenal glands in patients with hypovolemic shock was not significantly different (P = 0.81) from that (34%) in control subjects. Contrast enhancement effects of the adrenal glands at contrast-enhanced dynamic CT in patients with hypovolemic shock were similar to those in control subjects, indicating the preserved enhancement and perfusion of the adrenal gland rather than intense and persistent enhancement in patients with hypovolemic shock.

  1. A preliminary evaluation of self-made nanobubble in contrast-enhanced ultrasound imaging

    NASA Astrophysics Data System (ADS)

    Li, Chunfang; Wu, Kaizhi; Li, Jing; Liu, Haijuan; Zhou, Qibing; Ding, Mingyue

    2014-03-01

    Nanoscale bubbles (nanobubbles) have been reported to improve contrast in tumor-targeted ultrasound imaging due to the enhanced permeation and retention effects at tumor vascular leaks. In this work, a self-made nanobubble ultrasound contrast agent was preliminarily characterized and evaluated in-vitro and in-vivo. Fundamental properties such as morphology appearance, size distribution, zeta potential, bubble concentration (bubble numbers per milliliter contrast agent suspension) and the stability of nanobubbles were assessed by light microscope and particle sizing analysis. Then the concentration intensity curve and time intensity curves (TICs) were acquired by ultrasound imaging experiment in-vitro. Finally, the contrast-enhanced ultrasonography was performed on rat to investigate the procedure of liver perfusion. The results showed that the nanobubbles had good shape and uniform distribution with the average diameter of 507.9 nm, polydispersity index (PDI) of 0.527, and zeta potential of -19.17 mV. Significant contrast enhancement was observed in in-vitro ultrasound imaging, demonstrating that the self-made nanobubbles can enhance the contrast effect of ultrasound imaging efficiently in-vitro. Slightly contrast enhancement was observed in in-vivo ultrasound imaging, indicating that the nanobubbles are not stable enough in-vivo. Future work will be focused on improving the ultrasonic imaging performance, stability, and antibody binding of the nanoscale ultrasound contrast agent.

  2. [Simulation study of scan timing in three-dimensional contrast-enhanced MR angiography].

    PubMed

    Ohkubo, Masaki; Ohgoshi, Yukio; Inoue, Tomoko; Naito, Kenichi; Yagishita, Yuhko; Tsai, Du-Yih

    2002-05-01

    In our study of three-dimensional contrast-enhanced MR angiography, we performed a computer simulation to quantitatively investigate vessel visibility according to scan timing. To construct the simulated MR images, we varied the position (scan timing) and range (enhancement-duration) of k-space data assumed to be acquired during contrast enhancement. In the present study, either the sequential or centric phase-encoding order in k(y) and k(z) on k-space was assumed to be used. When scan timing was shifted from the optimal timing, the visibility of thick vessels decreased, and the signal intensity in thin vessels was higher than that in thick vessels. We found that the appropriate setting of scan timing was an important factor in the visibility of thick vessels. Meanwhile, we also noted that extending the enhancement-duration (or shortening the scan time) could increase the visibility of thin vessels. Our results and the simple technique used for simulation are considered to be useful for the study of three-dimensional contrast-enhanced MR angiography.

  3. Statistical comparison of dynamic contrast-enhanced MRI pharmacokinetic models in human breast cancer.

    PubMed

    Li, Xia; Welch, E Brian; Chakravarthy, A Bapsi; Xu, Lei; Arlinghaus, Lori R; Farley, Jaime; Mayer, Ingrid A; Kelley, Mark C; Meszoely, Ingrid M; Means-Powell, Julie; Abramson, Vandana G; Grau, Ana M; Gore, John C; Yankeelov, Thomas E

    2012-07-01

    By fitting dynamic contrast-enhanced MRI data to an appropriate pharmacokinetic model, quantitative physiological parameters can be estimated. In this study, we compare four different models by applying four statistical measures to assess their ability to describe dynamic contrast-enhanced MRI data obtained in 28 human breast cancer patient sets: the chi-square test (χ(2)), Durbin-Watson statistic, Akaike information criterion, and Bayesian information criterion. The pharmacokinetic models include the fast exchange limit model with (FXL_v(p)) and without (FXL) a plasma component, and the fast and slow exchange regime models (FXR and SXR, respectively). The results show that the FXL_v(p) and FXR models yielded the smallest χ(2) in 45.64 and 47.53% of the voxels, respectively; they also had the smallest number of voxels showing serial correlation with 0.71 and 2.33%, respectively. The Akaike information criterion indicated that the FXL_v(p) and FXR models were preferred in 42.84 and 46.59% of the voxels, respectively. The Bayesian information criterion also indicated the FXL_v(p) and FXR models were preferred in 39.39 and 45.25% of the voxels, respectively. Thus, these four metrics indicate that the FXL_v(p) and the FXR models provide the most complete statistical description of dynamic contrast-enhanced MRI time courses for the patients selected in this study.

  4. Contrast-enhanced digital mammography (CEDM): phantom experiment and first clinical results

    NASA Astrophysics Data System (ADS)

    Marx, Christiane; Facius, Mirijam; Muller, Serge L.; Benali, Karim; Malich, Ansgar; Kaiser, Werner

    2002-05-01

    The introduction of the Full Field Digital Mammography (FFDM) opens the way to a large range of future advanced applications. Among them, Contrast Enhanced Digital Mammography (CEDM) could be a fast and less expensive alternative to Magnetic Resonance Imaging (MRI) for breast lesion characterization. In this work, we have investigated, first on phantom then on patients, the capability of a modified FFDM system to show the contrast enhancement of lesions after intra-venous injection of iodine. The uptake has been estimated from the difference between pre- and post-contrast images. Phantom results showed that 1) detectability thresholds of the contrast media were compatible with clinical conditions; 2) breast radiological thickness has a low impact on uptake detectability; 3) spatial and temporal analysis showed delayed margin contrast uptake of the simulated lesion and slow increase of contrast in the background. Preliminary results on patients have confirmed the phantom results and have shown a contrast uptake in all malignant lesions despite the observed patient motion artifacts, and some moderate signal variability. This study demonstrated the feasibility of the Contrast Enhanced Digital Mammography technique. Further investigations and clinical validations will have to be completed before it can be widely used in a daily routine practice.

  5. Contrast-enhanced ultrasound for blunt hepatic trauma: an animal experiment.

    PubMed

    Yekuo, Li; Shasha, Wang; Xiansheng, Zhu; Qi, Chen; Guoxin, Luo; Feng, Huo

    2010-09-01

    The aim of this study was to study the value of contrast-enhanced ultrasound (CEUS) in the diagnosis of active hemorrhage and intraparenchymal lesions in blunt hepatic trauma versus conventional ultrasound (US). Twenty heparinized and anesthetized domestic pigs have been created to animal models with blunt hepatic trauma by a special impacting device. Conventional US and CEUS were performed to determine if hepatic traumas were present. Active hemorrhage, the presence of intraparenchymal lesions, and sonographic pattern were evaluated for conventional US and CEUS, as compared with laparotomy and pathologic findings. Contrast-enhanced US detected active hemorrhage from the injured livers in all cases, but conventional US did not find that in any case. The sensitivity of CEUS and conventional US in diagnosing intraparenchymal lesions of blunt hepatic trauma were 100% and 60%, respectively. Contrast-enhanced US is more sensitive than conventional US in determining the active hemorrhage and intraparenchymal lesions in blunt hepatic trauma. Crown Copyright © 2010. Published by Elsevier Inc. All rights reserved.

  6. Within-lesion differences in quantitative MRI parameters predict contrast enhancement in multiple sclerosis.

    PubMed

    Jurcoane, Alina; Wagner, Marlies; Schmidt, Christoph; Mayer, Christoph; Gracien, Rene-Maxime; Hirschmann, Marc; Deichmann, Ralf; Volz, Steffen; Ziemann, Ulf; Hattingen, Elke

    2013-12-01

    To investigate the relationship between quantitative magnetic resonance imaging (qMRI) and contrast enhancement in multiple sclerosis (MS) lesions. We compared maps of T1 relaxation time, proton density (PD), and magnetization transfer ratio (MTR) between lesions with and without contrast enhancement as quantified by the amount of T1 shortening postcontrast agent (CA). In 17 patients with relapsing-remitting MS (RRMS), 15 with progressive MS (PMS), and 17 healthy controls, T1, PD, and MTR were measured at 3T and T1-mapping was repeated after CA administration. Manually drawn MS-lesions (3D-FLAIR) were labeled as enhancing if post-CA T1-shortening exceeded mean T1-shortening in normal-appearing white matter (NAWM) by at least 2 standard deviations. Precontrast T1, PD, and MTR were compared in enhancing lesions, nonenhancing lesions, NAWM, and gray matter. Precontrast T1, PD, and MTR differed significantly between enhancing and nonenhancing lesions in RRMS and PMS patients (all P < 0.01). In PMS patients, PD of NAWM, enhancing, and nonenhancing lesions and MTR and T1 of gray matter differed significantly from RRMS and controls. Only MTR of gray matter differed between RRMS and controls. Contrast enhancement in MS quantified by relative T1 shortening may be predicted by precontrast abnormalities of T1, PD, and MTR and likely represents blood-brain barrier damage. Copyright © 2013 Wiley Periodicals, Inc.

  7. Age-related differences in skeletal muscle microvascular response to exercise as detected by contrast-enhanced ultrasound (CEUS)

    PubMed Central

    Hildebrandt, Wulf; Schwarzbach, Hans; Pardun, Anita; Hannemann, Lena; Bogs, Björn; König, Alexander M.; Mahnken, Andreas H.; Hildebrandt, Olaf; Koehler, Ulrich; Kinscherf, Ralf

    2017-01-01

    Background Aging involves reductions in exercise total limb blood flow and exercise capacity. We hypothesized that this may involve early age-related impairments of skeletal muscle microvascular responsiveness as previously reported for insulin but not for exercise stimuli in humans. Methods Using an isometric exercise model, we studied the effect of age on contrast-enhanced ultrasound (CEUS) parameters, i.e. microvascular blood volume (MBV), flow velocity (MFV) and blood flow (MBF) calculated from replenishment of Sonovue contrast-agent microbubbles after their destruction. CEUS was applied to the vastus lateralis (VLat) and intermedius (VInt) muscle in 15 middle-aged (MA, 43.6±1.5 years) and 11 young (YG, 24.1±0.6 years) healthy males before, during, and after 2 min of isometric knee extension at 15% of peak torque (PT). In addition, total leg blood flow as recorded by femoral artery Doppler-flow. Moreover, fiber-type-specific and overall capillarisation as well as fiber composition were additionally assessed in Vlat biopsies obtained from CEUS site. MA and YG had similar quadriceps muscle MRT-volume or PT and maximal oxygen uptake as well as a normal cardiovascular risk factors and intima-media-thickness. Results During isometric exercise MA compared to YG reached significantly lower levels in MFV (0.123±0.016 vs. 0.208±0.036 a.u.) and MBF (0.007±0.001 vs. 0.012±0.002 a.u.). In the VInt the (post-occlusive hyperemia) post-exercise peaks in MBV and MBF were significantly lower in MA vs. YG. Capillary density, capillary fiber contacts and femoral artery Doppler were similar between MA and YG. Conclusions In the absence of significant age-related reductions in capillarisation, total leg blood flow or muscle mass, healthy middle-aged males reveal impaired skeletal muscle microcirculatory responses to isometric exercise. Whether this limits isometric muscle performance remains to be assessed. PMID:28273102

  8. Contrast-Enhanced Ultrasound Differentiation Between Low and High-Grade Bladder Urothelial Carcinoma and Correlation With Tumor Microvessel Density.

    PubMed

    Guo, Suping; Xu, Pan; Zhou, Aiyun; Wang, Gongxian; Chen, Weimin; Mei, Jinhong; Xiao, Fan; Liu, Juan; Zhang, Cheng

    2017-05-27

    Time-intensity curves (TICs) of contrast-enhanced ultrasound (CEUS) were analyzed retrospectively to differentiate between low-grade and high-grade bladder urothelial carcinoma, and to investigate correlation with tumor microvessel density (MVD). The data of 105 patients with pathologically confirmed bladder urothelial carcinoma (55 low-grade and 50 high-grade) were reviewed. Lesions were examined before surgery using conventional ultrasound and CEUS with TIC analysis. The TIC parameters time from peak to one-half the signal intensity (TPH) and the corresponding descending slope (DS) of the low-grade and high-grade groups were compared, and receiver operating characteristic curves constructed. The MVDs of the resectioned tissue specimens were quantified via immunohistochemistry for CD34. Based on conventional ultrasound, the low-grade and high-grade groups were similar in tumor shape, number, topography, internal echo, height, width, and vascularity. The TPH of the high-grade group was significantly longer than that of the low-grade group, and the DS was lower. The cutoff points of TPH and DS for differentiating low-grade and high-grade bladder urothelial carcinoma were 48.06 seconds and 0.15 dB/seconds, respectively (area under the receiver operating characteristic curve = 0.79 for both). The mean MVDs per high-power field of the low-grade and high-grade groups were 41.39 16.65 and 51.03 20.16, respectively (P = .009). The TPH correlated linearly with MVD (P < .01), as did the DS (P < .01). Contrast-enhanced ultrasound can be used to differentiate low from high-grade bladder urothelial carcinoma. The TIC parameters of CEUS reflect the MVD of bladder urothelial tumors and may be helpful for evaluating tumor angiogenesis, with implications for clinical diagnosis, treatment, and prognosis. © 2017 by the American Institute of Ultrasound in Medicine.

  9. Multipurpose contrast enhancement on epiphyseal plates and ossification centers for bone age assessment

    PubMed Central

    2013-01-01

    Background The high variations of background luminance, low contrast and excessively enhanced contrast of hand bone radiograph often impede the bone age assessment rating system in evaluating the degree of epiphyseal plates and ossification centers development. The Global Histogram equalization (GHE) has been the most frequently adopted image contrast enhancement technique but the performance is not satisfying. A brightness and detail preserving histogram equalization method with good contrast enhancement effect has been a goal of much recent research in histogram equalization. Nevertheless, producing a well-balanced histogram equalized radiograph in terms of its brightness preservation, detail preservation and contrast enhancement is deemed to be a daunting task. Method In this paper, we propose a novel framework of histogram equalization with the aim of taking several desirable properties into account, namely the Multipurpose Beta Optimized Bi-Histogram Equalization (MBOBHE). This method performs the histogram optimization separately in both sub-histograms after the segmentation of histogram using an optimized separating point determined based on the regularization function constituted by three components. The result is then assessed by the qualitative and quantitative analysis to evaluate the essential aspects of histogram equalized image using a total of 160 hand radiographs that are implemented in testing and analyses which are acquired from hand bone online database. Result From the qualitative analysis, we found that basic bi-histogram equalizations are not capable of displaying the small features in image due to incorrect selection of separating point by focusing on only certain metric without considering the contrast enhancement and detail preservation. From the quantitative analysis, we found that MBOBHE correlates well with human visual perception, and this improvement shortens the evaluation time taken by inspector in assessing the bone age. Conclusions

  10. Quantifying Intracranial Plaque Permeability with Dynamic Contrast-Enhanced MRI: A Pilot Study

    PubMed Central

    Vakil, P.; Elmokadem, A.H.; Syed, F.H.; Cantrell, C.G.; Dehkordi, F.H.; Carroll, T.J.; Ansari, S.A.

    2016-01-01

    BACKGROUND AND PURPOSE Intracranial atherosclerotic disease plaque hyperintensity and/or gadolinium contrast enhancement have been studied as imaging biomarkers of acutely symptomatic ischemic presentations using single static MR imaging measurements. However, the value in modeling the dynamics of intracranial plaque permeability has yet to be evaluated. The purpose of this study was to use dynamic contrast-enhanced MR imaging to quantify the contrast permeability of intracranial atherosclerotic disease plaques in symptomatic patients and to compare these parameters against existing markers of plaque volatility using black-blood MR imaging pulse sequences. MATERIALS AND METHODS We performed a prospective study of contrast uptake dynamics in the major intracranial vessels proximal and immediately distal to the circle of Willis using dynamic contrast-enhanced MR imaging, specifically in patients with symptomatic intracranial atherosclerotic disease. Using the Modified Tofts model, we extracted the volume transfer constant (Ktrans) and fractional plasma volume (Vp) parameters from plaque-enhancement curves. Using regression analyses, we compared these parameters against time from symptom onset as well as intraplaque hyperintensity and postcontrast enhancement derived from T1 SPACE, a black-blood MR vessel wall imaging sequence. RESULTS We completed analysis in 10 patients presenting with symptomatic intracranial atherosclerotic disease. Ktrans and Vp measurements were higher in plaques versus healthy white matter and similar or less than values in the choroid plexus. Only Ktrans correlated significantly with time from symptom onset (P = .02). Dynamic contrast-enhanced MR imaging parameters were not found to correlate significantly with intraplaque enhancement or intraplaque hyperintensity (P = .4 and P = .17, respectively). CONCLUSIONS Elevated Ktrans and Vp values found in intracranial atherosclerotic disease plaques versus healthy white matter suggest that dynamic

  11. Evaluation of indeterminate renal masses with contrast-enhanced US: a diagnostic performance study.

    PubMed

    Barr, Richard G; Peterson, Cynthia; Hindi, Ammar

    2014-04-01

    To determine the utility of contrast material-enhanced ultrasonography (US) in the characterization of indeterminate renal masses. This retrospective performance study was approved by the institutional review board and was HIPAA compliant, with waiver of informed consent. Patients included 721 individuals referred for contrast-enhanced US with 1018 indeterminate renal masses from 1999 to 2010, identified initially with an imaging study. Three hundred twenty patients (44.4%) were female, and 401 (55.6%) were male. Patient ages ranged from 17 to 95 years (mean ± standard deviation, 70 years ± 15). Lesion size varied from 2 to 161 mm (mean, 26.6 mm ± 19.5). Contrast-enhanced US enhancement patterns were used to characterize masses as benign or malignant. For lesions with a definitive diagnosis, 306 of 1018 (30.0%) were correlated with contrast-enhanced US findings: 167 (54.6%) were benign, and 139 (45.4%) were malignant. For lesions without a pathologic diagnosis, 712 (70.0%) were followed for as long as 10 years. Diagnostic accuracy measures were calculated by using pathologic diagnosis as the reference standard, as well as lesion stability at 3 and 5 years. Contrast-enhanced US had a sensitivity of 100% (126 of 126; 95% confidence interval [CI]: 97.1%, 100%), specificity of 95.0% (132 of 139; 95% CI: 89.9%, 98.0%), positive predictive value (PPV) of 94.7% (126 of 133), and negative predictive value (NPV) of 100% (132 of 132). The five false-positive masses included three oncocytomas and two Bosniak category 3 cystic lesions. Of the 290 lesions that had follow-up of at least 36 months, none of the lesions demonstrated changes that necessitated lesion reclassification. If these lesions were included, assuming lesions classified as malignant were malignant, then of the 596 lesions, sensitivity was 100% (161 of 161), specificity was 96.6% (420 of 435), PPV was 91.5% (161 of 176), and NPV was 100% (420 of 420). Contrast-enhanced US evaluation is a highly sensitive and

  12. Clinical value of classification of venous malformations with contrast-enhanced MR Angiography.

    PubMed

    Abdel Razek, Ahmed Abdel Khalek; Albair, Germeen Ashmalla; Samir, Sieza

    2017-10-01

    Aim To classify venous malformations based on contrast-enhanced MR angiography that may serve as a basis for treatment plan. Patients and methods A retrospective analysis was performed in 58 patients with venous malformations who underwent contrast-enhanced MR angiography. Venous malformations were classified according to their venous drainage into: type I, isolated malformation without peripheral drainage; type II, malformation that drains into normal veins; type III, malformation that drains into dilated veins; and type IV, malformation that represents dysplastic venous ectasia. Image analysis was done by two reviewers. Intra and inter-observer agreement of both reviewers and intra-class correlation was done. Results The intra-observer agreement of contrast-enhanced MR angiography classification of venous malformations was excellent for the first reviewer ( k = 0.83, 95% CI = 0.724-0.951, P = 0.001) and substantial for the second reviewer ( K = 0.79, 95% CI = 0.656-0.931, P = 0.001). The inter-observer agreement of contrast-enhanced MR angiography classification of venous malformations was excellent for both reviewers at the first time ( K = 0.96, 95% CI = 0.933-1.000, P = 0.001) and second time ( k = 0.81, 95% CI = 0.678-0.942, P = 0.001). There was high intra-class correlation of both reviewers for single measure ( ICC = 0.85, 95% CI = 0.776-0.918, P = 0.001) and for average measures ( ICC = 0.96, 95% CI = 0.933-0.978, P = 0.001). Conclusion Contrast-enhanced MR angiography classification of venous malformations may be a useful, simple and reliable tool to accurately classify venous malformation and this topographic classification helps for better management strategy.

  13. Contrast-enhancement influences skeletal muscle density, but not skeletal muscle mass, measurements on computed tomography.

    PubMed

    van Vugt, Jeroen L A; Coebergh van den Braak, Robert R J; Schippers, Henk J W; Veen, Kevin M; Levolger, Stef; de Bruin, Ron W F; Koek, Marcel; Niessen, Wiro J; IJzermans, Jan N M; Willemsen, François E J A

    2017-07-14

    Low skeletal muscle mass and density have recently been discovered as prognostic and predictive parameters to guide interventions in various populations, including cancer patients. The gold standard for body composition analysis in cancer patients is computed tomography (CT). To date, the effect of contrast-enhancement on muscle composition measurements has not been established. The aim of this study was to determine the effect of contrast-enhancement on skeletal muscle mass and density measurements on four-phase CT studies. In this observational study, two observers measured cross-sectional skeletal muscle area corrected for patients' height (skeletal muscle index [SMI]) and density (SMD) at the level of the third lumbar vertebra on 50 randomly selected CT examinations with unenhanced, arterial, and portal-venous phases. The levels of agreement between enhancement phases for SMI and SMD were calculated using intra-class correlation coefficients (ICCs). Mean SMI was 42.5 (±9.9) cm(2)/m(2) on the unenhanced phase, compared with 42.8 (±9.9) and 43.6 (±9.9) cm(2)/m(2) for the arterial and portal-venous phase, respectively (both p < 0.01). Mean SMD was lower for the unenhanced phase (30.9 ± 8.0 Hounsfield units [HU]) compared with the arterial (38.0 ± 9.9 HU) and portal-venous (38.7 ± 9.2 HU) phase (both p < 0.001). No significant difference was found between SMD in the portal-venous and arterial phase (p = 0.161). The ICCs were excellent (≥0.992) for all SMIs and for SMD between the contrast-enhanced phases (0.949). The ICCs for the unenhanced phase compared with the arterial (0.676) and portal-venous (0.665) phase were considered fair to good. Statistically significant differences in SMI were observed between different enhancement phases. However, further work is needed to assess the clinical relevance of these small differences. Contrast-enhancement strongly influenced SMD values. Studies using this measure should therefore use the portal

  14. Anatomical noise in contrast-enhanced digital mammography. Part I. Single-energy imaging

    SciTech Connect

    Hill, Melissa L.; Yaffe, Martin J.; Mainprize, James G.; Carton, Ann-Katherine; Muller, Serge; Ebrahimi, Mehran; Jong, Roberta A.; Dromain, Clarisse

    2013-05-15

    Purpose: The use of an intravenously injected iodinated contrast agent could help increase the sensitivity of digital mammography by adding information on tumor angiogenesis. Two approaches have been made for clinical implementation of contrast-enhanced digital mammography (CEDM), namely, single-energy (SE) and dual-energy (DE) imaging. In each technique, pairs of mammograms are acquired, which are then subtracted with the intent to cancel the appearance of healthy breast tissue to permit sensitive detection and specific characterization of lesions. Patterns of contrast agent uptake in the healthy parenchyma, and uncanceled signal from background tissue create a 'clutter' that can mask or mimic an enhancing lesion. This type of 'anatomical noise' is often the limiting factor in lesion detection tasks, and thus, noise quantification may be useful for cascaded systems analysis of CEDM and for phantom development. In this work, the authors characterize the anatomical noise in CEDM clinical images and the authors evaluate the influence of the x-ray energy used for acquisition, the presence of iodine in the breast, and the timing of imaging postcontrast administration on anatomical noise. The results are presented in a two-part report, with SE CEDM described here, and DE CEDM in Part II. Methods: A power law is used to model anatomical noise in CEDM images. The exponent, {beta}, which describes the anatomical structure, and the constant {alpha}, which represents the magnitude of the noise, are determined from Wiener spectra (WS) measurements on images. A total of 42 SE CEDM cases from two previous clinical pilot studies are assessed. The parameters {alpha} and {beta} are measured both from unprocessed images and from subtracted images. Results: Consistent results were found between the two SE CEDM pilot studies, where a significant decrease in {beta} from a value of approximately 3.1 in the unprocessed images to between about 1.1 and 1.8 in the subtracted images was

  15. Anatomical noise in contrast-enhanced digital mammography. Part I. Single-energy imaging.

    PubMed

    Hill, Melissa L; Mainprize, James G; Carton, Ann-Katherine; Muller, Serge; Ebrahimi, Mehran; Jong, Roberta A; Dromain, Clarisse; Yaffe, Martin J

    2013-05-01

    The use of an intravenously injected iodinated contrast agent could help increase the sensitivity of digital mammography by adding information on tumor angiogenesis. Two approaches have been made for clinical implementation of contrast-enhanced digital mammography (CEDM), namely, single-energy (SE) and dual-energy (DE) imaging. In each technique, pairs of mammograms are acquired, which are then subtracted with the intent to cancel the appearance of healthy breast tissue to permit sensitive detection and specific characterization of lesions. Patterns of contrast agent uptake in the healthy parenchyma, and uncanceled signal from background tissue create a "clutter" that can mask or mimic an enhancing lesion. This type of "anatomical noise" is often the limiting factor in lesion detection tasks, and thus, noise quantification may be useful for cascaded systems analysis of CEDM and for phantom development. In this work, the authors characterize the anatomical noise in CEDM clinical images and the authors evaluate the influence of the x-ray energy used for acquisition, the presence of iodine in the breast, and the timing of imaging postcontrast administration on anatomical noise. The results are presented in a two-part report, with SE CEDM described here, and DE CEDM in Part II. A power law is used to model anatomical noise in CEDM images. The exponent, β, which describes the anatomical structure, and the constant α, which represents the magnitude of the noise, are determined from Wiener spectra (WS) measurements on images. A total of 42 SE CEDM cases from two previous clinical pilot studies are assessed. The parameters α and β are measured both from unprocessed images and from subtracted images. Consistent results were found between the two SE CEDM pilot studies, where a significant decrease in β from a value of approximately 3.1 in the unprocessed images to between about 1.1 and 1.8 in the subtracted images was observed. Increasing the x-ray energy from that used

  16. Temporomandibular joint (TMJ) pain revisited with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI).

    PubMed

    Tasali, N; Cubuk, R; Aricak, M; Ozarar, M; Saydam, B; Nur, H; Tuncbilek, N

    2012-03-01

    We aimed to assess the contrast enhancement patterns of the retrodiscal tissue with dynamic contrast-enhanced MR imaging (DCE-MRI) with respect to different temporomandibular joint disc pathologies. Additionally, we questioned the relationship between the temporomandibular joint (TMJ) pain and the contrast enhancement pattern of the retrodiscal tissue regardless of the TMJ disc position. 52 joints of 26 patients (4 males and 22 females) who have pain in at least at one of their TMJ were included in this study. For the qualitative analysis, the joints were divided into four groups in terms of their disc positions: normal (1), partially displaced with or without reduction (2), totally dislocated with reduction (3) and totally dislocated without reduction (4). Besides, two different joint groups were constituted, namely the painful group and painless group according to the clinical findings without taking the TMJ disc positions into account. Quantitative analyses were made by means of measuring signal intensity ratios (SI) ratio at the retrodiscal tissue (from internal side and external side of the each joint) using DCE-MRI and these measurements were analyzed with paired samples t test to define the difference between the measurements. At the second stage, the time-dependent arithmetical mean values of the SI ratios were calculated for each joint group and significant differences between the groups were questioned using analysis of variance (ANOVA) test. Besides, painful and painless groups which were classified on the basis of the clinical data were compared according to the mean SI ratios found for each joint and the significant differences between these two groups were assessed by means of Student's T test. The results were assessed in 95% confidence interval where the significance level was p<0.05. A significant difference was observed between the internal and external contrast enhancement of the joints with partial displacement. Another significant difference

  17. Imaging Modalities for Assessment of Treatment Response to Nonsurgical Hepatocellular Carcinoma Therapy: Contrast-Enhanced US, CT, and MRI.

    PubMed

    Minami, Yasunori; Kudo, Masatoshi

    2015-03-01

    Tumor response and time to progression have been considered pivotal for surrogate assessment of treatment efficacy for patients with hepatocellular carcinoma (HCC). Recent advancements in imaging modalities such as contrast-enhanced ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI) are playing an important role in assessing the therapeutic effects of HCC treatments. According to some HCC clinical guidelines, post-therapeutic evaluation of HCC patients is based exclusively on contrast-enhanced dynamic imaging criteria. The recommended techniques are contrast-enhanced CT or contrast-enhanced MRI. Contrast-enhanced US is employed more in the positive diagnosis of HCC than in post-therapeutic monitoring. Although contrast enhancement is an important finding on imaging, enhancement does not necessarily depict the same phenomenon across modalities. We need to become well acquainted with the characteristics of each modality, including not only contrast-enhanced CT and MRI but also contrast-enhanced US. Many nonsurgical treatment options are now available for unresectable HCC, and accurate assessment of tumor response is essential to achieve favorable outcomes. For the assessment of successful radiofrequency ablation (RFA), the achievement of a sufficient ablation margin as well the absence of tumor vascular enhancement is essential. To evaluate the response to transcatheter arterial chemoembolization (TACE), enhanced tumor shrinkage is relied on as a measure of antitumor activity. Here, we give an overview of the current status of imaging assessment of HCC response to nonsurgical treatments including RFA and TACE.

  18. Automatic hyperspectral camera for latent fingerprint detection and contrast enhancement. Final report, September 2, 1998 - March 17, 1999

    SciTech Connect

    Paul Shnitser

    1999-06-01

    Physical Optics Corporation demonstrated the feasibility of the contrast enhancement of the latent fingerprint by portable hyperspectral imaging camera. The demonstrated non-contact technology is applicable for observation of the low contrast laser excited fluorescence from latent fingerprints as well as for the contrast enhancement of chemically processed fingerprints. Experiments were conducted with fingerprints on various types of substrates.

  19. Three-dimensional contrast enhanced ultrasound score and dynamic contrast-enhanced magnetic resonance imaging score in evaluating breast tumor angiogenesis: correlation with biological factors.

    PubMed

    Jia, Wan-Ru; Chai, Wei-Min; Tang, Lei; Wang, Yi; Fei, Xiao-Chun; Han, Bao-San; Chen, Man

    2014-07-01

    To explore the clinical value of three-dimensional contrast enhanced ultrasound (3D-CEUS) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) score systems in evaluating breast tumor angiogenesis by comparing their diagnostic efficacy and correlation with biological factors. 3D-CEUS was performed in 183 patients with breast tumors by Esaote Mylab90 with SonoVue (Bracco, Italy), DCE-MRI was performed on a dedicated breast magnetic resonance imaging (DBMRI) system (Aurora Dedicated Breast MRI Systems, USA) with a dedicated breast coil. 3D-CEUS and DCE-MRI score systems were created based on tumor perfusion and vascular characteristics. Microvessel density (MVD), vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMP-2, MMP-9) expression were measured by immunohistochemistry. Pathological results showed 35 benign and 148 malignant breast tumors. MVD (P=0.000, r=0.76), VEGF (P=0.000, r=0.55), MMP-2 (P=0.000, r=0.39) and MMP-9 (P=0.000, r=0.41) expression were all significantly different between benignity and malignancy. Regarding 3D-CEUS 4 points as cutoff value, the sensitivity, specificity and accuracy were 85.1%, 94.3% and 86.9%, respectively, and correlated well with MVD (P=0.000, r=0.50), VEGF (P=0.000, r=0.50), MMP-2 (P=0.000, r=0.50) and MMP-9 (P=0.000, r=0.66). Taking DCE-MRI 5 points as cutoff value, the sensitivity, specificity and accuracy were 86.5%, 94.3% and 88.0%, respectively and also correlated well with MVD (P=0.000, r=0.52), VEGF (P=0.000, r=0.44), MMP-2 (P=0.000, r=0.42) and MMP-9 (P=0.000, r=0.35). 3D-CEUS score system displays inspiring diagnostic performance and good agreement with DCE-MRI scoring. Moreover, both score systems correlate well with MVD, VEGF, MMP-2 and MMP-9 expression, and thus have great potentials in tumor angiogenesis evaluation. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  20. An evaluation of the clinical diagnostic value of contrast-enhanced ultrasound combined with contrast-enhanced computed tomography in space-occupying lesions of the kidney.

    PubMed

    Tian, Wen; Lu, Jianbo; Jiao, Dan; Cong, Zhibin

    2017-01-01

    There are a variety of space-occupying lesions of the kidney, and the benign lesions may be difficult to differentiate from the malignant ones. Therefore, an accurate judgment of the benign and malignant nature of the space-occupying lesions of the kidney is of high importance for the treatment and prognosis of these patients. To evaluate the diagnostic value of contrast-enhanced ultrasound (CEUS) combined with contrast-enhanced computed tomography (CECT) in space-occupying lesions of the kidney. Three hundred and sixty-seven patients with space-occupying lesions of the kidney (378 lesions) were examined by CEUS and CECT, respectively, then, a combined diagnosis was made after the combination of CEUS and CECT by a multidisciplinary team. The diagnoses from the three methods were compared. The pathological results were taken as the gold standard. The sensitivity, specificity, positive and negative predictive values and area under the receiver operating characteristic (ROC) curve were calculated for the three methods. Thus, the diagnostic value of the three methods was assessed. Of the 378 lesions examined, there were 301 malignant lesions and 77 benign lesions. The combined examination revealed 303 malignant lesions, with 9 benign lesions mistakenly diagnosed as malignant ones; thus, the misdiagnosis rate was 11.7%. By using the combined examination, 75 benign lesions were diagnosed, with the missed diagnosis of 7 malignant lesions, so the missed diagnosis rate was 2.3%. The sensitivity, specificity, positive and negative predictive values and area under the ROC curve with the combined examination of CEUS and CECT were 97.67% (0.950-0.989), 88.31% (0.785-0.942), 97.03% (0.942-0.985), 90.67% (0.811-0.958) and 0.930 (0.887-0.973), respectively. As compared with either CEUS or CECT alone, the difference in these indicators was of statistical significance (P<0.05). The combined examination greatly improved the sensitivity, specificity and accuracy of the diagnosis of

  1. Diagnostic value of contrast-enhanced ultrasonography in the characterization of ovarian tumors().

    PubMed

    Sconfienza, L M; Perrone, N; Delnevo, A; Lacelli, F; Murolo, C; Gandolfo, N; Serafini, G

    2010-03-01

    Sommario INTRODUZIONE: La ricchezza della componente vascolare dei tumori ginecologici influenza le caratteristiche dell'imaging diretto, utilizzando metodiche che evidenziano la componente macrovascolare delle lesioni (color e power Doppler), e di quello indiretto, mediante somministrazione di mezzi di contrasto (MdC) per lo studio del microcircolo e della perfusione interstiziale. Lo scopo di questo lavoro è di valutare l'aggiunta di informazioni diagnostiche fornite dalla valutazione ecografica con MdC nello studio delle lesioni ovariche. MATERIALI E METODI: Abbiamo valutato 72 lesioni annessiali in 61 pazienti con lesioni ovariche di incerta interpretazione mediante somministrazione di 4,8 ml di MdC ecoamplificatore di II generazione. Per ogni lesione, abbiamo valutato la morfologia basale, quella contrastografica e le curve intensità/tempo. RISULTATI: La valutazione post-contrasto confrontata con la basale non ha apportato informazioni aggiuntive morfovascolari in 8 pazienti (13,1%); in 38 pazienti (62,3%) ha apportato informazioni senza modifiche del comportamento clinico; in 15 soggetti (24,6%) ha apportato elementi che hanno modificato il comportamento clinico. Le lesioni maligne presentavano valori di tempo massimo di enhancement significativamente minori (11,9 ± 3,1 s vs 19,8 ± 4,0 s p < 0,01) e intensità di picco massimo significativamente maggiore (24,7 ± 4,2 dB vs 17,8 ± 3,3 dB p < 0,01) rispetto alle lesioni benigne. CONCLUSIONI: La CEUS consente di migliorare la confidenza diagnostica nelle lesioni liquide corpuscolate in cui l'indagine convenzionale non risulta dirimente, proponendosi nella diagnosi differenziale di un limitato numero di lesioni complesse, in alternativa a TC ed RM. Le informazioni ottenute influenzano tuttavia il successivo iter diagnostico e terapeutico in una limitata percentuale di casi (24,6%).

  2. Optimization of contrast-enhanced breast imaging: Analysis using a cascaded linear system model.

    PubMed

    Hu, Yue-Houng; Scaduto, David A; Zhao, Wei

    2017-01-01

    Contrast-enhanced (CE) breast imaging involves the injection contrast agents (i.e., iodine) to increase conspicuity of malignant lesions. CE imaging may be used in conjunction with digital mammography (DM) or digital breast tomosynthesis (DBT) and has shown promise in improving diagnostic specificity. Both CE-DM and CE-DBT techniques require optimization as clinical diagnostic tools. Physical factors including x-ray spectra, subtraction technique, and the signal from iodine contrast, must be considered to provide the greatest object detectability and image quality. We developed a cascaded linear system model (CLSM) for the optimization of CE-DM and CE-DBT employing dual energy (DE) subtraction or temporal (TE) subtraction. We have previously developed a CLSM for DBT implemented with an a-Se flat panel imager (FPI) and filtered backprojection (FBP) reconstruction algorithm. The model is used to track image quality metrics - modulation transfer function (MTF) and noise power spectrum (NPS) - at each stage of the imaging chain. In this study, the CLSM is extended for CE breast imaging. The effect of x-ray spectrum (varied by changing tube potential and the filter) and DE and TE subtraction techniques on breast structural noise was measured was studied and included as a deterministic source of noise in the CLSM. From the two-dimensional (2D) and three-dimensional (3D) MTF and NPS, the ideal observer signal-to-noise ratio (SNR), also known as the detectability index (d'), may be calculated. Using d' as a FOM, we discuss the optimization of CE imaging for the task of iodinated contrast object detection within structured backgrounds. Increasing x-ray energy was determined to decrease the magnitude of structural noise and not its correlation. By performing DE subtraction, the magnitude of the structural noise was further reduced at the expense of increased stochastic (quantum and electronic) noise. TE subtraction exhibited essentially no residual structural noise at the

  3. Photon counting CT of the liver with dual-contrast enhancement

    NASA Astrophysics Data System (ADS)

    Muenzel, Daniela; Proksa, Roland; Daerr, Heiner; Fingerle, Alexander A.; Pfeiffer, Franz; Rummeny, Ernst J.; Noël, Peter B.

    2016-03-01

    The diagnostic quality of photon counting computed tomography (PCCT) is one the unexplored areas in medical imaging; at the same time, it seems to offer the opportunity as a fast and highly sensitive diagnostic tool. Today, conventional computed tomography (CT) is the standard imaging technique for diagnostic evaluation of the parenchyma of the liver. However, considerations on radiation dose are still an important factor in CT liver imaging, especially with regard to multi-phase contrast enhanced CT. In this work we report on a feasibility study for multi-contrast PCCT for simultaneous liver imaging at different contrast phases. PCCT images of the liver were simulated for a contrast-enhanced examination performed with two different contrast agents (CA), iodine (CA 1) and gadolinium (CA 2). PCCT image acquisition was performed at the time point with portal venous contrast distribution of CA 1 and arterial contrast phase for CA 2. Therefore, a contrast injection protocol was planned with sequential injection of CA 1 and CA 2 to provide a time dependent difference in contrast distribution of both CAs in the vessels and parenchyma of the liver. Native, arterial, and portal venous contrast enhanced images have been calculated based on the spectral separation of PCCT. In simulated PCCT images, we were able to differentiate between the tissue enhancement of CA 1 and CA 2. The distribution of both CA within the parenchyma of the liver was illustrated with perfusion maps for CA 1 and CA 2. In addition, virtual noncontrast enhanced image were calculated. In conclusion, multi-phase PCCT imaging of the liver based on a single scan is a novel approach for spectral PCCT imaging, offering detailed contrast information in a single scan volume and a significant reduction of radiation dose.

  4. Casein-coated iron oxide nanoparticles for high MRI contrast enhancement and efficient cell targeting.

    PubMed

    Huang, Jing; Wang, Liya; Lin, Run; Wang, Andrew Y; Yang, Lily; Kuang, Min; Qian, Weiping; Mao, Hui

    2013-06-12

    Surface properties, as well as inherent physicochemical properties, of the engineered nanomaterials play important roles in their interactions with the biological systems, which eventually affect their efficiency in diagnostic and therapeutic applications. Here we report a new class of MRI contrast agent based on milk casein protein-coated iron oxide nanoparticles (CNIOs) with a core size of 15 nm and hydrodynamic diameter ~30 nm. These CNIOs exhibited excellent water-solubility, colloidal stability, and biocompatibility. Importantly, CNIOs exhibited prominent T2 enhancing capability with a transverse relaxivity r2 of 273 mM(-1) s(-1) at 3 tesla. The transverse relaxivity is ~2.5-fold higher than that of iron oxide nanoparticles with the same core but an amphiphilic polymer coating. CNIOs showed pH-responsive properties, formed loose and soluble aggregates near the pI (pH ~4.0). The aggregates could be dissociated reversibly when the solution pH was adjusted away from the pI. The transverse relaxation property and MRI contrast enhancing effect of CNIOs remained unchanged in the pH range of 2.0-8.0. Further functionalization of CNIOs can be achieved via surface modification of the protein coating. Bioaffinitive ligands, such as a single chain fragment from the antibody of epidermal growth factor receptor (ScFvEGFR), could be readily conjugated onto the protein coating, enabling specific targeting to MDA-MB-231 breast cancer cells overexpressing EGFR. T2-weighted MRI of mice intravenously administered with CNIOs demonstrated strong contrast enhancement in the liver and spleen. These favorable properties suggest CNIOs as a class of biomarker targeted magnetic nanoparticles for MRI contrast enhancement and related biomedical applications.

  5. [Baseline and contrast-enhanced ultrasound of the liver in tumor patients].

    PubMed

    Oldenburg, A; Albrecht, T

    2008-10-01

    In patients with known malignancy, correct detection and characterization of liver lesions has important therapeutic consequences. Conventional sonography is the most commonly used modality for liver imaging in tumor patients. However, it has a lower sensitivity for the detection of liver metastases compared to contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI). The majority of liver metastases are hypoechoic and well defined in baseline ultrasound (US), while detection of isoechoic or small liver metastases <1 cm is difficult and the differentiation of liver metastases from benign liver lesions and other malignant liver tumors can be impossible with baseline US. The use of microbubble-based ultrasound contrast agents and contrast-specific imaging techniques advanced the accuracy of ultrasound in liver imaging. Levovist and SonoVue are the US contrast agents approved for liver imaging in Europe. Compared to Levovist, SonoVue allows continuous imaging of the liver in real-time over a period of up to 5 minutes. As a result, SonoVue became the preferred contrast agent for liver imaging in the recent years, while Levovist became less important. Important for the detection of liver metastases are the portal venous and late phases in which metastases show a wash-out and can be detected as hypoechoic lesions in homogeneous enhanced liver parenchyma. The detection of hepatic metastases is substantially improved by CEUS compared to conventional B-mode sonography. Several studies showed sensitivity in detecting liver metastases comparable to that of contrast-enhanced CT and MRI. Furthermore, the typical enhancement patterns of the different benign and malignant liver lesions allow reliable characterization and differentiation from liver metastases in the majority of cases. This paper provides information about the advantages and expedient application of contrast-enhanced ultrasound (CEUS) in tumor patients.

  6. Ileal Crohn disease: mural microvascularity quantified with contrast-enhanced US correlates with disease activity.

    PubMed

    De Franco, Antonio; Di Veronica, Alessandra; Armuzzi, Alessandro; Roberto, Italia; Marzo, Manuela; De Pascalis, Barbara; De Vitis, Italo; Papa, Alfredo; Bock, Enrico; Danza, Francesco M; Bonomo, Lorenzo; Guidi, Luisa

    2012-02-01

    To quantitatively assess microvascular activation in the thickened ileal walls of patients with Crohn disease (CD) by using contrast-enhanced ultrasonography (US) and evaluate its correlation with widely used indexes of CD activity. This prospective study was approved by the ethics committee, and written informed consent was obtained from all patients. The authors examined 54 consecutively enrolled patients (mean age, 35.29 years; age range, 18-69 years; 39 men, 15 women) with endoscopically confirmed CD of the terminal ileum. Ileal wall segments thicker than 3 mm were examined with low-mechanical-index contrast-enhanced US and a second-generation US contrast agent. The authors analyzed software-plotted time-enhancement intensity curves to determine the maximum peak intensity (MPI) and wash-in slope coefficient (β) and evaluated their correlation with (a) the composite index of CD activity (CICDA), (b) the CD activity index (CDAI), and (c) the simplified endoscopic score for CD (SES-CD, evaluated in 37 patients) for the terminal ileum. Statistical analysis was performed with the Mann-Whitney test, Spearman rank test, and receiver operating characteristic (ROC) analysis. MPI and β coefficients were significantly increased in the 36 patients with a CICDA indicative of active disease (P<.0001 for both), the 33 patients with a CDAI of at least 150 (P<.032 and P<.0074, respectively), and the 26 patients with an SES-CD of at least 1 (P<.0001 and P<.002, respectively). ROC analysis revealed accurate identification (compared with CICDA) of active CD with an MPI threshold of 24 video intensity (VI) (sensitivity, 97%; specificity, 83%) and a β coefficient of 4.5 VI/sec (sensitivity, 86%; specificity, 83%). Contrast-enhanced US of the ileal wall is a promising method for objective, reproducible assessment of disease activity in patients with ileal CD. © RSNA, 2011

  7. Blunt splenic trauma: can contrast enhanced sonography be used for the screening of delayed pseudoaneurysms?

    PubMed

    Poletti, Pierre-Alexandre; Becker, Christoph D; Arditi, Daniel; Terraz, Sylvain; Buchs, Nicolas; Shanmuganathan, Kathirkamanathan; Platon, Alexandra

    2013-11-01

    To assess the value of contrast-enhanced sonography (CES) for the detection of delayed post-traumatic splenic pseudo-aneurysms, usually considered an indication for angiographic embolization. Sixty-three consecutive hemodynamically stable trauma patients in whom admission CT displayed a splenic injury of grade II or higher (AAST classification), without evidence of vascular involvement, were included in the study. CES of the spleen using a second generation contrast agent was systematically performed within 48-72 h after admission, for the detection of a pooling of contrast media suggestive of pseudoaneurysm. Within 6h after contrast-enhanced sonography, all patients underwent an abdominal CT for control purposes. CES results were compared to CT findings, which were considered the reference standard. This study received approval from the institutional ethical board. CES showed a blush of contrast consistent with a pseudoaneurysm in 6 of the 63 patients. All were confirmed at subsequent control CT. Pooling of contrast was found at CT in 2 patients in whom contrast-enhanced sonography was negative. There was no false positive CES examination for the suspicion of pseudoaneurysms. When compared to CT, the sensitivity, specificity, positive and negative predictive values of CES to suggest a pseudoaneurysms, were 75% (6/8), 100% (55/55), 100% (6/6), and 96% (55/57), respectively. Our data suggest that CES may be useful for the screening of delayed traumatic splenic pseudoaneurysms: if a negative CES does not absolutely rule out a pseudoaneurysm, a positive CES warrants an angiography, without need of control CT. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  8. Automatic segmentation and quantification of the cardiac structures from non-contrast-enhanced cardiac CT scans

    NASA Astrophysics Data System (ADS)

    Shahzad, Rahil; Bos, Daniel; Budde, Ricardo P. J.; Pellikaan, Karlijn; Niessen, Wiro J.; van der Lugt, Aad; van Walsum, Theo

    2017-05-01

    Early structural changes to the heart, including the chambers and the coronary arteries, provide important information on pre-clinical heart disease like cardiac failure. Currently, contrast-enhanced cardiac computed tomography angiography (CCTA) is the preferred modality for the visualization of the cardiac chambers and the coronaries. In clinical practice not every patient undergoes a CCTA scan; many patients receive only a non-contrast-enhanced calcium scoring CT scan (CTCS), which has less radiation dose and does not require the administration of contrast agent. Quantifying cardiac structures in such images is challenging, as they lack the contrast present in CCTA scans. Such quantification would however be relevant, as it enables population based studies with only a CTCS scan. The purpose of this work is therefore to investigate the feasibility of automatic segmentation and quantification of cardiac structures viz whole heart, left atrium, left ventricle, right atrium, right ventricle and aortic root from CTCS scans. A fully automatic multi-atlas-based segmentation approach is used to segment the cardiac structures. Results show that the segmentation overlap between the automatic method and that of the reference standard have a Dice similarity coefficient of 0.91 on average for the cardiac chambers. The mean surface-to-surface distance error over all the cardiac structures is 1.4+/- 1.7 mm. The automatically obtained cardiac chamber volumes using the CTCS scans have an excellent correlation when compared to the volumes in corresponding CCTA scans, a Pearson correlation coefficient (R) of 0.95 is obtained. Our fully automatic method enables large-scale assessment of cardiac structures on non-contrast-enhanced CT scans.

  9. Usefulness of contrast-enhanced intraoperative ultrasound using Sonazoid in patients with hepatocellular carcinoma.

    PubMed

    Arita, Junichi; Takahashi, Michiro; Hata, Shojiro; Shindoh, Junichi; Beck, Yoshifumi; Sugawara, Yasuhiko; Hasegawa, Kiyoshi; Kokudo, Norihiro

    2011-12-01

    To assess the usefulness of contrast-enhanced intraoperative ultrasound (CE-IOUS) using Sonazoid (gaseous perflubutane) in patients with hepatocellular carcinoma (HCC). Contrast-enhanced intraoperative ultrasound using Sonazoid, a novel ultrasonic contrast agent enabling Kupffer imaging, may enable differentiation of HCC among new focal liver lesions found during fundamental intraoperative ultrasound (fundamental-NFLLs). Between February 2007 and February 2009, a total of 192 consecutive patients were enrolled. Fundamental intraoperative ultrasound and CE-IOUS were performed successively after laparotomy. The vascularity of 1 representative lesion was examined in harmonic mode for approximately 1 minute after the intravenous injection of Sonazoid (vascular phase). Approximately 15 minutes after the vascular phase, total liver scanning in the harmonic mode was commenced (Kupffer phase). One additional injection of Sonazoid was allowed to examine the vascularity of another lesion, if necessary. A tentative diagnosis of HCC was made when a lesion was either hypervascular during the vascular phase or hypoechoic during the Kupffer phase. A final diagnosis of HCC was made on the basis of the results of a histological examination or dynamic computed tomography findings obtained during the 12-month postoperative period. Seventy-nine fundamental-NFLLs were found in 50 patients (26%), 17 (22%) of which were finally diagnosed as HCC. The sensitivity, specificity, and accuracy of CE-IOUS for differentiating HCC among fundamental-NFLLs were 65%, 94%, and 87%, respectively. Contrast-enhanced intraoperative ultrasound identified 21 additional new hypoechoic lesions in 16 patients, of which 14 lesions (67%) in 11 patients were finally diagnosed as HCC. This prospective study protocol was approved by the institutional review board of the Tokyo University Hospital. An English-language summary of the protocol was submitted (registration ID: UMIN000003046) to the Clinical Trials

  10. FEASIBILITY AND SAFETY OF CONTRAST-ENHANCED ULTRASOUND IN THE DISTAL LIMB OF SIX HORSES.

    PubMed

    Seiler, Gabriela S; Campbell, Nigel; Nixon, Britton; Tsuruta, James K; Dayton, Paul A; Jennings, Samuel; Redding, W Rich; Lustgarten, Meghann

    2016-05-01

    Vascular alterations play important roles in many orthopedic diseases such as osteoarthritis, tendonitis, and synovitis in both human and equine athletes. Understanding these alterations could enhance diagnosis, prognosis, and treatment. Contrast-enhanced ultrasound (CEUS) could be a valuable method for evaluation of blood flow and perfusion of these processes in the equine distal limb, however no reports were found describing feasibility or safety of the technique. The goal of this prospective, experimental study was to describe the feasibility and safety of distal limb CEUS in a sample of six horses. For each horse, CEUS of the distal limb was performed after intravenous injections of 5 and 10 ml, as well as intra-arterial injections of 0.5 and 1 ml contrast medium. Vital parameters were monitored and CEUS images were assessed qualitatively and quantitatively for degree of contrast enhancement. None of the horses had clinically significant changes in their vital parameters after contrast medium injection. One horse had a transient increase in respiratory rate, and several horses had mild increases of systolic blood pressure of short duration after intravenous, but not after intra-arterial injections. Intra-arterial injection was possible in all horses and resulted in significantly improved contrast enhancement both quantitatively (P = 0.027) and qualitatively (P = 0.019). Findings from this study indicated that CEUS is a feasible and safe diagnostic test for evaluation of the equine distal limb. Future studies are needed to assess the clinical utility of this test for horses with musculoskeletal diseases. © 2016 American College of Veterinary Radiology.

  11. Pituitary Macroadenoma and Visual Impairment: Postoperative Outcome Prediction with Contrast-Enhanced FIESTA.

    PubMed

    Hisanaga, S; Kakeda, S; Yamamoto, J; Watanabe, K; Moriya, J; Nagata, T; Fujino, Y; Kondo, H; Nishizawa, S; Korogi, Y

    2017-09-14

    Contrast-enhanced FIESTA can depict anterior optic pathways in patients with large suprasellar tumors. We assessed whether the degree of kink in the optic nerve at the optic canal orifice on contrast-enhanced FIESTA correlates with the postoperative improvement of visual impairment in patients with pituitary macroadenoma. Thirty-one patients with pituitary macroadenoma who underwent preoperative MR imaging and an operation were evaluated. We measured the optic nerve kinking angle on sagittal oblique contrast-enhanced FIESTA parallel to the optic nerve; the optic nerve kinking angle was defined as the angle between a line parallel to the planum sphenoidale and a line parallel to the intracranial optic nerve at the optic canal orifice. We used logistic regression analyses to determine whether the clinical (sex, age, and duration of symptoms) and imaging (tumor height, chiasmal compression severity, hyperintense optic nerve on T2WI, and optic nerve kinking angle) characteristics were associated with the postoperative improvement (good-versus-little improvement) of visual acuity disturbance and visual field defect. There were 53 impaired sides before the operation: 2 sides with visual acuity disturbance alone, 25 with visual field defect alone, and 26 with both. After the operation, good improvement was found in 17 of the 28 sides with visual acuity disturbance and in 32 of the 51 sides with visual field defects. Only the optic nerve kinking angle was significantly associated with good improvement of the visual acuity disturbance (P = .011) and visual field defect (P = .002). The degree of the optic nerve kinking angle was an independent predictor of postoperative improvement, indicating that irreversible damage to the optic nerve may be associated with its kinking at the optic canal orifice. © 2017 American Society of Neuroradiology.

  12. Dynamic contrast-enhanced MR imaging features of the normal central zone of the prostate.

    PubMed

    Hansford, Barry G; Karademir, Ibrahim; Peng, Yahui; Jiang, Yulei; Karczmar, Gregory; Thomas, Stephen; Yousuf, Ambereen; Antic, Tatjana; Eggener, Scott; Oto, Aytekin

    2014-05-01

    Evaluate qualitative dynamic contrast-enhanced magnetic resonance imaging (MRI) characteristics of normal central zone based on recently described central zone MRI features. Institutional review board-approved, Health Insurance Portability and Accountability Act compliant study, 59 patients with prostate cancer, histopathology proven to not involve central zone or prostate base, underwent endorectal MRI before prostatectomy. Two readers independently reviewed T2-weighted images and apparent diffusion coefficient (ADC) maps identifying normal central zone based on low signal intensity and location. Next, two readers drew bilateral central zone regions of interest on dynamic contrast-enhanced magnetic resonance images in consensus and independently recorded enhancement curve types as type 1 (progressive), type 2 (plateau), and type 3 (wash-out). Identification rates of normal central zone and enhancement curve type were recorded and compared for each reviewer. The institutional review board waiver was approved and granted 05/2010. Central zone identified in 92%-93% of patients on T2-weighted images and 78%-88% on ADC maps without significant difference between identification rates (P = .63 and P = .15 and inter-reader agreement (κ) is 0.64 and 0.29, for T2-weighted images and ADC maps, respectively). All central zones were rated either curve type 1 or curve type 2 by both radiologists. No statistically significant difference between the two radiologists (P = .19) and inter-reader agreement was κ = 0.37. Normal central zone demonstrates either type 1 (progressive) or type 2 (plateau) enhancement curves on dynamic contrast-enhanced MRI that can be potentially useful to differentiate central zone from prostate cancer that classically demonstrates a type 3 (wash-out) enhancement curve. Copyright © 2014 AUR. Published by Elsevier Inc. All rights reserved.

  13. Reproducibility of chronic infarct size measurement by contrast-enhanced magnetic resonance imaging.

    PubMed

    Mahrholdt, Heiko; Wagner, Anja; Holly, Thomas A; Elliott, Michael D; Bonow, Robert O; Kim, Raymond J; Judd, Robert M

    2002-10-29

    The reproducibility of contrast-enhanced MRI has not been established. We compared MRI reproducibility for infarct size determination with that of (99m)Tc-sestamibi (MIBI) single photon emission computed tomography (SPECT). Patients with chronic myocardial infarction defined by enzymes (peak creatine kinase-MB 173+/-119 U/L) were scanned twice by MRI (MRI I and MRI II, n=20) and twice by SPECT (SPECT I and SPECT II, n=15) on the same day. The MRI contrast agent was injected during MRI I but not MRI II to test the effect of imaging time after contrast. Resting Tc-MIBI SPECT images were acquired and infarct size was determined with commercial software. Infarct size in patients scanned by MRI and SPECT was 14+/-6% of left ventricular mass (%LV) by MRI (range 4%LV to 27%LV) and 14+/-7%LV by SPECT (range 4%LV to 26%LV). MRI I and II scans were performed 10+/-2 and 27+/-3 minutes after contrast, respectively. For MRI, the difference in infarct size between scans I and II (bias) was -0.1%LV, and the coefficient of repeatability was +/-2.4%LV. For SPECT, bias was -1.3%LV, and the coefficient of repeatability was +/-4.0%LV. Within individual patients, no systematic differences in infarct size were detected when the 2 MRI scans were compared, the 2 SPECT scans were compared, or MRI was compared to SPECT. The size of healed infarcts measured by contrast-enhanced MRI does not change between 10 and 30 minutes after contrast. The clinical reproducibility of contrast-enhanced MRI for infarct size determination compares favorably with that of routine clinical SPECT.

  14. Journal Club: Comparison of assessment of preoperative pulmonary vasculature in patients with non-small cell lung cancer by non-contrast- and 4D contrast-enhanced 3-T MR angiography and contrast-enhanced 64-MDCT.

    PubMed

    Ohno, Yoshiharu; Nishio, Mizuho; Koyama, Hisanobu; Yoshikawa, Takeshi; Matsumoto, Sumiaki; Seki, Shinichiro; Sugimura, Kazuro

    2014-03-01

    The purpose of this article is to prospectively and directly compare the capabilities of non-contrast-enhanced MR angiography (MRA), 4D contrast-enhanced MRA, and contrast-enhanced MDCT for assessing pulmonary vasculature in patients with non-small cell lung cancer (NSCLC) before surgical treatment. A total of 77 consecutive patients (41 men and 36 women; mean age, 71 years) with pathologically proven and clinically assessed stage I NSCLC underwent thin-section contrast-enhanced MDCT, non-contrast-enhanced and contrast-enhanced MRA, and surgical treatment. The capability for anomaly assessment of the three methods was independently evaluated by two reviewers using a 5-point visual scoring system, and final assessment for each patient was made by consensus of the two readers. Interobserver agreement for pulmonary arterial and venous assessment was evaluated with the kappa statistic. Then, sensitivity, specificity, and accuracy for the detection of anomalies were directly compared among the three methods by use of the McNemar test. Interobserver agreement for pulmonary artery and vein assessment was substantial or almost perfect (κ=0.72-0.86). For pulmonary arterial and venous variation assessment, there were no significant differences in sensitivity, specificity, and accuracy among non-contrast-enhanced MRA (pulmonary arteries: sensitivity, 77.1%; specificity, 97.4%; accuracy, 87.7%; pulmonary veins: sensitivity, 50%; specificity, 98.5%; accuracy, 93.2%), 4D contrast-enhanced MRA (pulmonary arteries: sensitivity, 77.1%; specificity, 97.4%; accuracy, 87.7%; pulmonary veins: sensitivity, 62.5%; specificity, 100.0%; accuracy, 95.9%), and thin-section contrast-enhanced MDCT (pulmonary arteries: sensitivity, 91.4%; specificity, 89.5%; accuracy, 90.4%; pulmonary veins: sensitivity, 50%; specificity, 100.0%; accuracy, 95.9%) (p>0.05). Pulmonary vascular assessment of patients with NSCLC before surgical resection by non-contrast-enhanced MRA can be considered equivalent to

  15. High sensitivity contrast enhanced optical coherence tomography for functional in vivo imaging

    NASA Astrophysics Data System (ADS)

    Liba, Orly; SoRelle, Elliott D.; Sen, Debasish; de la Zerda, Adam

    2017-02-01

    In this study, we developed and applied highly-scattering large gold nanorods (LGNRs) and custom spectral detection algorithms for high sensitivity contrast-enhanced optical coherence tomography (OCT). We were able to detect LGNRs at a concentration as low as 50 pM in blood. We used this approach for noninvasive 3D imaging of blood vessels deep in solid tumors in living mice. Additionally, we demonstrated multiplexed imaging of spectrally-distinct LGNRs that enabled observations of functional drainage in lymphatic networks. This method, which we call MOZART, provides a platform for molecular imaging and characterization of tissue noninvasively at cellular resolution.

  16. Assessment and Monitoring Tumor Vascularity With Contrast-Enhanced Ultrasound Maximum Intensity Persistence Imaging

    PubMed Central

    Pysz, Marybeth A.; Foygel, Kira; Panje, Cedric M.; Needles, Andrew; Tian, Lu; Willmann, Jürgen K.

    2015-01-01

    Objectives Contrast-enhanced ultrasound imaging is increasingly being used in the clinic for assessment of tissue vascularity. The purpose of our study was to evaluate the effect of different contrast administration parameters on the in vivo ultrasound imaging signal in tumor-bearing mice using a maximum intensity persistence (MIP) algorithm and to evaluate the reliability of in vivo MIP imaging in assessing tumor vascularity. The potential of in vivo MIP imaging for monitoring tumor vascularity during antiangiogenic cancer treatment was further evaluated. Materials and Methods In intraindividual experiments, varying contrast microbubble concentrations (5 × 105, 5 × 106, 5 × 107, 5 × 108 microbubbles in 100 µL saline) and contrast injection rates (0.6, 1.2, and 2.4 mL/min) in subcutaneous tumor-bearing mice were applied and their effects on in vivo contrast-enhanced ultrasound MIP imaging plateau values were obtained using a dedicated small animal ultrasound imaging system (40 MHz). Reliability of MIP ultrasound imaging was tested following 2 injections of the same micro-bubble concentration (5 × 107 microbubbles at 1.2 mL/min) in the same tumors. In mice with subcutaneous human colon cancer xenografts, longitudinal contrast-enhanced ultrasound MIP imaging plateau values (baseline and at 48 hours) were compared between mice with and without antiangiogenic treatment (anti-vascular endothelial growth factor antibody). Ex vivo CD31 immunostaining of tumor tissue was used to correlate in vivo MIP imaging plateau values with microvessel density analysis. Results In vivo MIP imaging plateau values correlated significantly (P = 0.001) with contrast microbubble doses. At 3 different injection rates of 0.6, 1.2, and 2.4 mL/min, MIP imaging plateau values did not change significantly (P = 0.61). Following 2 injections with the same microbubble dose and injection rate, MIP imaging plateau values were obtained with high reliability with an intraclass correlation

  17. Optimization Of Phase-Contrast Enhanced X-Ray Imaging Of D-T Layers

    SciTech Connect

    Kozioziemski, B

    2005-06-17

    Phase-contrast enhanced x-ray imaging has been demonstrated for characterization of D-T layers inside of beryllium shells. These first demonstrations used both scintillator and direct-detection imaging. This memo details tradeoffs between the two methods in order to optimize the imaging. The guiding principle for optimization is to minimize the exposure time while maximizing the signal-to-noise ratio at the D-T solid-vapor interface. Direct-detection and scintillator performance are comparable when imaging the full capsule. However, a scintillator allows for higher-resolution images necessary for studying local defects in the D-T layer.

  18. High resolution 3 Tesla contrast-enhanced MR angiography of the hands in Raynaud's disease.

    PubMed

    Walcher, J; Strecker, R; Goldacker, S; Winterer, J; Langer, M; Bley, T A

    2007-04-01

    Raynaud's disease is associated with disorders in blood circulation of the hands. The gold standard to visualise pathology of digital arteries is catheter angiography. Contrast-enhanced MR angiography (CE MRA) has developed even more as an alternative non-invasive method to digital subtraction angiography, mostly for pelvic or lower limb vessels. We report a case of primary Raynaud's disease with high-grade stenosis and an occlusion of the digital arteries. This case illustrates the benefit and efficiency of CE MRA at high fields in depicting location and extension of peripheral arterial alterations.

  19. Optical switching and contrast enhancement in intense laser systems by cascaded optical parametric amplification

    SciTech Connect

    Jovanovic, I; Haefner, C; Wattellier, B; Barty, C J

    2005-09-06

    Optical parametric chirped-pulse amplification (OPCPA) can be used to improve the prepulse contrast in chirped-pulse amplification systems by amplifying the main pulse with a total saturated OPCPA gain, while not affecting the preceding prepulses of the seed oscillator mode-locked pulse train. We show that a simple modification of a multistage OPCPA system into a cascaded optical parametric amplifier (COPA) results in an optical switch and extreme contrast enhancement which can completely eliminate the preceding and trailing oscillator pulses. Instrument-limited measurement of prepulse contrast ratio of 1.4 x 10{sup 11} is demonstrated from COPA at a 30-mJ level.

  20. A novel method for viability assessment by cinematographic and late contrast enhanced MRI

    NASA Astrophysics Data System (ADS)

    Gao, Gang; Cockshott, Paul W.; Martin, Thomas N.; Foster, John E.; Elliott, Alex; Dargie, Henry; Groenning, Bjoern A.

    2004-04-01

    Using cardiac magnetic resonance (MR) imaging, a combination of late contrast enhanced MR (ceMR) and cinematographic (CINE) images, a myocardial viability score can be derived. At present this score is produced by visual evaluation of wall motion abnormalities in combination with presence or absence of late hyper enhancement (LE) on ceMR. We set out to develop and validate image processing techniques derived from stereo vision capable of reducing the observer dependence and improving accuracy in the diagnosis of viable myocardium.

  1. Model-based reconstruction for undersampled dynamic contrast-enhanced MRI

    NASA Astrophysics Data System (ADS)

    Felsted, Ben K.; Whitaker, Ross T.; Schabel, Matthias; DiBella, Edward V. R.

    2009-02-01

    This paper describes a method for estimating, from dynamic contrast-enhanced MRI raw k-space data of the breast, parameter maps that model tissue properties associated with a compartmental model of contrast exchange. The contrast agent kinetics, as represented by these parameter maps, are important in distinguishing benign and malignant tumors. The proposed model-based reconstruction algorithm estimates tissue parameter maps directly from MRI k-space data, thereby allowing a new and improved set of spatiotemporal resolution and noise tradeoffs. Realistic noise levels and an undersampling factor of R=4 appeared to provide reasonable accuracy for the kinetic parameters of interest.

  2. What do we know about brain contrast enhancement patterns in neuromyelitis optica?☆

    PubMed Central

    Pekcevik, Yeliz; Orman, Gunes; Lee, In Ho; Mealy, Maureen A.; Levy, Michael; Izbudak, Izlem

    2016-01-01

    Neuromyelitis optica (NMO) is an autoimmune disorder of the central nervous system that usually presents with acute myelitis and/or optic neuritis. Recently, some brain magnetic resonance imaging findings have been described in NMO that are important in the differential diagnosis. Pencil-thin, leptomeningeal, and cloud-like enhancement may be specific to NMO. These patterns are usually seen during relapses. Recognizing these lesions and enhancement patterns may expedite the diagnosis and allows early effective treatment. The purpose of this article is to review the latest knowledge and to share our experience with the contrast enhancement patterns of NMO brain lesions. PMID:26615899

  3. Benefits of dynamic susceptibility-weighted contrast-enhanced perfusion MRI for glioma diagnosis and therapy

    PubMed Central

    Barajas, Ramon Francisco; Cha, Soonmee

    2014-01-01

    SUMMARY Glioma are the most common supra-tentorial brain tumor in the USA with an estimated annual incidence of 17,000 new cases per year. Dynamic susceptibility-weighted contrast-enhanced (DSC) perfusion MRI noninvasively characterizes tumor biology allowing for the diagnosis and therapeutic monitoring of glioma. This MRI technique utilizes the rapid changes in signal intensity caused by a rapid intravascular bolus of paramagnetic contrast agent to calculate physiologic perfusion metrics. DSC perfusion MRI has increasingly become an integrated part of glioma imaging. The specific aim of this article is to review the benefits of DSC perfusion MRI in the therapy of glioma. PMID:25438812

  4. Contrast-Enhanced Three Dimensional Ultrasonography supporting HIFU treatment of Small Liver Cancer

    NASA Astrophysics Data System (ADS)

    Ohto, Masao; Fukuda, Hiroyuki; Ito, Ryu; Shinohara, Yasushi; Sakamoto, Akio; Karasawa, Eii

    2009-04-01

    HIFU was carried out in the 12 patients with small hepatocellular carcinoma (small HCC) as a extracorporeal ablation therapy, and clinical availability was studied from the results. In carrying out the HIFU therapy, contrast enhanced (CE) three dimensional (3D) ultrasound imaging played an important role to clarify the tumor nature , to monitor the sonication procedure and to assess the tumor ablation and was almost indispensable for the treatment. All the patient had no serious side effects and they are all alive with no local tumor progression for 3 to 14 months after the treatment. Ultrasound supporting HIFU therapy could be usefully available for the treatment of small HCC.

  5. Posterior Urethra Rupture: Contrast-Enhanced Computed Tomography Scan and Urethrocystography Demonstrations

    PubMed Central

    Marks, Wojciech; Dawid, S.; Lasek, J.; Witkowski, Z.; Gołąbek-Dropiewska, K.; Stasiak, M.

    2012-01-01

    In the follow-up study of patients with pelvic fractures, rupture of the posterior urethra is registered in 3–25% of cases (Koraitim et al., 1996). The diagnostic gold standard for the assessment of hemodynamically stable trauma patients is contrast-enhanced CT scan, especially helical CT. Nevertheless, simultaneous suprapubic cystography and ascending urethrograms (the so-called up-and-downogram) are the investigation of choice in assessing the site, severity, and length of urethral injuries. (Carlin and Resnick, 1995) This paper discusses the evaluation and diagnosis of urethral injury in multiple-trauma patient. PMID:22606630

  6. Porcine Ex Vivo Liver Phantom for Dynamic Contrast-Enhanced Computed Tomography: Development and Initial Results

    PubMed Central

    Thompson, Scott M.; Giraldo, Juan C. Ramirez; Knudsen, Bruce; Grande, Joseph P.; Christner, Jodie A.; Xu, Man; Woodrum, David A.; McCollough, Cynthia H.; Callstrom, Matthew R.

    2011-01-01

    Objectives To demonstrate the feasibility of developing a fixed, dual-input, biological liver phantom for dynamic contrast-enhanced computed tomography (CT) imaging and to report initial results of use of the phantom for quantitative CT perfusion imaging. Materials and Methods Porcine livers were obtained from completed surgical studies and perfused with saline and fixative. The phantom was placed in a body-shaped, CT-compatible acrylic container and connected to a perfusion circuit fitted with a contrast injection port. Flow-controlled contrast-enhanced imaging experiments were performed using a 128-slice and 64 slice, dual-source multidetector CT scanners. CT angiography protocols were employed to obtain portal venous and hepatic arterial vascular enhancement, reproduced over a period of four to six months. CT perfusion protocols were employed at different input flow rates to correlate input flow with calculated tissue perfusion, to test reproducibility and demonstrate the feasibility of simultaneous dual input liver perfusion. Histologic analysis of the liver phantom was also performed. Results CT angiogram 3D reconstructions demonstrated homogenous tertiary and quaternary branching of the portal venous system out to the periphery of all lobes of the liver as well as enhancement of the hepatic arterial system to all lobes of the liver and gallbladder throughout the study period. For perfusion CT, the correlation between the calculated mean tissue perfusion in a volume of interest and input pump flow rate was excellent (R2 = 0.996) and color blood flow maps demonstrated variations in regional perfusion in a narrow range. Repeat perfusion CT experiments demonstrated reproducible time-attenuation curves and dual-input perfusion CT experiments demonstrated that simultaneous dual input liver perfusion is feasible. Histologic analysis demonstrated that the hepatic microvasculature and architecture appeared intact and well preserved at the completion of four to six

  7. Application of contrast-enhanced ultrasound after liver transplantation: Current status and perspectives

    PubMed Central

    Ren, Jie; Wu, Tao; Zheng, Bo-Wen; Tan, Ying-Yi; Zheng, Rong-Qin; Chen, Gui-Hua

    2016-01-01

    Liver transplantation is an effective treatment for patients with end-stage liver disease. Accurate imaging evaluation of the transplanted patient is critical for ensuring that the limited donor liver is functioning appropriately. Ultrasound contrast agents (UCAs), in combination with contrast-specific imaging techniques, are increasingly accepted in clinical use for the assessment of the hepatic vasculature, bile ducts and liver parenchyma in pre-, intra- and post-transplant patients. We describe UCAs, their technical requirements, the recommended clinical indications, image interpretation and the limitations for contrast-enhanced ultrasound applications in liver transplantation. PMID:26819526

  8. Cardiac Amyloidosis: Typical Imaging Findings and Diffuse Myocardial Damage Demonstrated by Delayed Contrast-Enhanced MRI

    SciTech Connect

    Sueyoshi, Eijun Sakamoto, Ichiro; Okimoto, Tomoaki; Hayashi, Kuniaki; Tanaka, Kyouei; Toda, Genji

    2006-08-15

    Amyloidosis is a rare systemic disease. However, involvement of the heart is a common finding and is the most frequent cause of death in amyloidosis. We report the sonographic, scintigraphic, and MRI features of a pathologically proven case of cardiac amyloidosis. Delayed contrast-enhanced MR images, using an inversion recovery prepped gradient-echo sequence, revealed diffuse enhancement in the wall of both left and right ventricles. This enhancement suggested expansion of the extracellular space of the myocardium caused by diffuse myocardial necrosis secondary to deposition of amyloid.

  9. A numerical study of gradient-based nonlinear optimization methods for contrast enhanced optical tomography.

    PubMed

    Roy, R; Sevick-Muraca, E

    2001-07-02

    Numerical performance of two gradient-based methods, a truncated-Newton method with trust region (TN) and a nonlinear conjugate gradient (NCG), is studied and compared for a given data set and conditions specific for the contrast enhanced optical tomography problem. Our results suggest that the relative performance of the two methods depends upon the error functions, specific to the problem to be solved. The TN outperforms the NCG when maps of fluorescence lifetime are reconstructed while both methods performed well when the absorption coefficient constitutes the parameter set that is to be recovered.

  10. Resolution and contrast enhancement of subtractive second harmonic generation microscopy with a circularly polarized vortex beam

    PubMed Central

    Tian, Nian; Fu, Ling; Gu, Min

    2015-01-01

    We extend the subtractive imaging method to label-free second harmonic generation (SHG) microscopy to enhance the spatial resolution and contrast. This method is based on the intensity difference between two images obtained with circularly polarized Gaussian and doughnut-shaped beams, respectively. By characterizing the intensity and polarization distributions of the two focused beams, we verify the feasibility of the subtractive imaging method in polarization dependent SHG microscopy. The resolution and contrast enhancement in different biological samples is demonstrated. This work will open a new avenue for the applications of SHG microscopy in biomedical research. PMID:26364733

  11. Nonrigid registration and classification of the kidneys in 3D dynamic contrast enhanced (DCE) MR images

    NASA Astrophysics Data System (ADS)

    Yang, Xiaofeng; Ghafourian, Pegah; Sharma, Puneet; Salman, Khalil; Martin, Diego; Fei, Baowei

    2012-02-01

    We have applied image analysis methods in the assessment of human kidney perfusion based on 3D dynamic contrast-enhanced (DCE) MRI data. This approach consists of 3D non-rigid image registration of the kidneys and fuzzy C-mean classification of kidney tissues. The proposed registration method reduced motion artifacts in the dynamic images and improved the analysis of kidney compartments (cortex, medulla, and cavities). The dynamic intensity curves show the successive transition of the contrast agent through kidney compartments. The proposed method for motion correction and kidney compartment classification may be used to improve the validity and usefulness of further model-based pharmacokinetic analysis of kidney function.

  12. Applications of contrast-enhanced harmonic endoscopic ultrasound on biliary, focal liver lesions and vascular diseases

    PubMed Central

    Choi, Jun-Ho; Seo, Dong-Wan

    2017-01-01

    Over the last decade, the clinical applications of contrast-enhanced harmonic endoscopic ultrasound (CH-EUS) have increased steadily. The development of second-generation ultrasound contrast agents has allowed superior visualization of the microvasculature and tissue perfusion of the target lesion. This methodology has proven useful in the differential diagnosis of solid pancreatic masses and lymph nodes. In addition, the applicability of CH-EUS has expanded to nonpancreas structures such as biliary, focal liver lesions, and vascular disease. This article focuses primarily on the novel applications of CH-EUS in biliary tract and visceral vascular diseases. PMID:28218196

  13. Differentiation between ductal carcinoma in situ and mastopathy using dynamic contrast-enhanced magnetic resonance imaging and a model of contrast enhancement.

    PubMed

    Nishiura, Motoko; Tamaki, Yasuhiro; Murase, Kenya

    2011-12-01

    The purpose of this study was to retrospectively evaluate the feasibility of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to differentiate between ductal carcinoma in situ (DCIS) and mastopathy by analyzing their time-intensity curves (TICs) using the two-compartment pharmacokinetic model with an assumption of instantaneous injection of contrast medium (TCPM). After the pre-contrast MRI was performed using a 1.5 T MRI system, DCE-MRI was performed four times after the intravenous administration of contrast medium. We set the volumes of interest (VOIs) on the tumor and normal mammary gland, and obtained the TICs in these VOIs. We calculated the following parameters by fitting these TICs to the equation derived from TCPM; the initial slope of the TIC (Slopeini), the area under the TIC (AUC), the time to peak enhancement (TTP) and the peak enhancement (PeakE). We calculated these parameters in both the lesion and normal mammary gland and the ratios of the parameters in the lesion to those in the normal gland (rSlopeini, rAUC, rTTP and rPeakE). There were significant differences in Slopeini (P=0.009), PeakE (P=0.019), rSlopeini (P=0.010), and rTTP (P=0.005) between DCIS and mastopathy. The areas under the receiver operating characteristic curve for Slopeini, PeakE, rSlopeini, and rTTP were 0.67±0.06 (P=0.009), 0.65±0.06 (P=0.019), 0.67±0.06 (P=0.01), and 0.68±0.06 (P=0.005), respectively. In conclusion, our results suggest that analysis of TICs obtained by DCE-MRI using TCPM appears to be useful for differentiating between DCIS and mastopathy. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  14. Ovarian size and vascularization as assessed by three-dimensional grayscale and power Doppler ultrasound in asymptomatic women 20-39 years old using combined oral contraceptives.

    PubMed

    Jokubkiene, Ligita; Sladkevicius, Povilas; Valentin, Lil

    2012-09-01

    The aim of this study is to estimate ovarian volume, number and volume of antral follicles, and ovarian power Doppler vascular indices as assessed by three-dimensional (3D) transvaginal grayscale and power Doppler ultrasound in women using combined oral contraceptives (COC). Two hundred thirteen gynecologically asymptomatic women 20-39 years old using COC were examined with transvaginal 3D grayscale and power Doppler ultrasound on cycle day 4-8 (first cycle day is first day of withdrawal bleeding). We used a Voluson E8 ultrasound system with a 6-12-MHz transvaginal transducer. Ovarian volume, number and volume of antral follicles ≥2 mm, vascularization index (VI), flow index (FI) and vascularization flow index (VFI) were calculated using the virtual organ computer-aided analysis (VOCAL™) and sonography-based automated volume calculation (SonoAVC™) software. Results are described separately for women with follicles 2.0-10.0 mm and for those with at least one follicle >10.0 mm for two age groups: 20-29 years (n=166) and 30-39 years (n=47). Results are also compared between women on monophasic (n=151) and triphasic (n=59) COC, and between women using COC with older (n=110) and newer (n=100) progestins and different doses of estrogen. One hundred eighty-nine (89%) women had follicles 2.0-10.0 mm, and 24 (11%) had follicle(s) >10.0 mm. The proportion of women with follicle(s) >10.0 mm did not differ between women with different types of COC. In women with follicles 2.0-10.0 mm, the right ovary was larger (mean difference 0.5 cm(3) [95% confidence interval 0.22-0.82]) and contained more follicles (mean difference 1.5 [0.52-2.56]) than the left one in the age group 20-29 years. The same differences between the right and left ovary were seen in women 30-39 years old, but they were not statistically significant. In both ovaries, the number of antral follicles 2.0-10.0 mm [median (range)] was significantly higher in women 20-29 than in those 30-39 years old [11 (2

  15. Clinical value of dynamic 3-dimensional contrast-enhanced ultrasound imaging for the assessment of hepatocellular carcinoma ablation.

    PubMed

    Wang, Yandong; Jing, Xiang; Ding, Jianmin

    2016-01-01

    The aim of the study was to investigate the performance of dynamic 3-dimensional contrast-enhanced ultrasound (3D-CEUS) on assessment of efficacy of local ablation therapy of hepatocellular carcinoma (HCC) with contrast-enhanced computed tomography (CT) as reference standard. Eighty-nine HCC lesions from 75 patients undergoing ultrasound-guided percutaneous thermal ablation or chemical ablation were studied by both dynamic 3D-CEUS and contrast-enhanced CT 1month after ablation. Imaging results from two imaging modalities were evaluated independently by experienced readers to determine whether the treated lesions were ablated incompletely (residual unablated tumor) or completely. Sensitivity, specificity, positive and negative predictive values, and accuracy to identify incomplete ablation were calculated for dynamic 3D-CEUS imaging with contrast-enhanced CT as reference standard. Contrast-enhanced CT reported that 80.9% (72/89) of all the treated lesions were completely ablated and 19.1% (17/89) were incompletely ablated. The dynamic 3D-CEUS identified 82.0% (73/89) and 18.0% (16/89) of lesions as completely and incompletely ablated, respectively. With contrast-enhanced CT as the reference standard, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of dynamic 3D-CEUS for identifying residual unablated tumor were 88.2% (15/17), 98.6% (71/72), 93.8% (15/16), 97.3% (71/73), and 96.6% (86/89), respectively. The Kappa value for identifying residual unablated tumor between contrast-enhanced CT and dynamic 3D-CEUS was 0.89. Dynamic 3D-CEUS is highly consistent with contrast-enhanced CT in assessment of efficacy of HCC ablation and has potential to serve as an alternative to contrast-enhanced CT in the follow-up assessment after HCC ablation. Published by Elsevier Inc.

  16. Evaluation of contrast enhancement by carbon nanotubes for microwave-induced thermoacoustic tomography.

    PubMed

    Song, Jian; Zhao, Zhiqin; Wang, Jinguo; Zhu, Xiaozhang; Wu, Jiangniu; Nie, Zaiping; Liu, Qing-Huo

    2015-03-01

    Microwave-induced thermoacoustic tomography (MITAT) is a hybrid method which constructs images with ultrasound spatial resolution while exploiting dielectric contrast at microwave frequency. It has great potential in biomedical imaging especially in early breast cancer detection. The detection of early stage breast tumor in MITAT is challenged by the moderate endogenous dielectric contrast between malignant and healthy glandular tissues. In order to overcome this limitation, the performance of using carbon nanotubes (CNTs) as an imaging contrast enhancement agent is evaluated. First, the influences in dielectric and acoustic properties caused by CNTs are measured. Second, based on the measurements and the published data, numerical breast phantom is created and then used to explore the contrast enhancing effect of CNTs for MITAT, by an integrated simulation approach in both electromagnetic and acoustic field. With an experimental MITAT system, the thermoacoustic responses of tissue mimicking materials with different CNTs concentrations are also quantitatively investigated. Finally, the effectiveness of the contrast agent is also validated experimentally by using a MITAT system. The results show that the using of the dielectric contrast agent can effectively enhance the contrast of the MITAT image.