Contrast-enhanced Power Doppler Research Articles

Super-resolution ultrasound localization microscopy based on a high frame-rate clinical ultrasound scanner: an in-human feasibility study

Non-invasive detection of microvascular alterations in deep tissues in vivo provides critical information for clinical diagnosis and evaluation of a broad-spectrum of pathologies. Recently, the emergence of super-resolution ultrasound localization microscopy (ULM) offers new possibilities for clinical imaging of microvasculature at capillary level. Currently, the clinical utility of ULM on clinical ultrasound scanners is hindered by the technical limitations, such as long data acquisition time, high microbubble (MB) concentration, and compromised tracking performance associated with low imaging frame-rate. Here we present a robust in-human ULM on a high frame-rate (HFR) clinical ultrasound scanner to achieve super-resolution microvessel imaging using a short acquisition time (<10 s). Ultrasound MB data were acquired from different human tissues, including a healthy liver and a diseased liver with acute-on-chronic liver failure, a kidney, a pancreatic tumor, and a breast mass using an HFR clinical scanner. By leveraging the HFR and advanced processing techniques including sub-pixel motion registration, MB signal separation, and Kalman filter-based tracking, MBs can be robustly localized and tracked for ULM under the circumstances of relatively high MB concentration associated with standard clinical MB administration and limited data acquisition time in humans. Subtle morphological and hemodynamic information in microvasculature were shown based on data acquired with single breath-hold and free-hand scanning. Compared with contrast-enhanced power Doppler generated based on the same MB dataset, ULM showed a 5.7-fold resolution improvement in a vessel based on a linear transducer, and provided a wide-range blood flow speed measurement that is Doppler angle-independent. Microvasculatures with complex hemodynamics can be well-differentiated at super-resolution in both normal and pathological tissues. This preliminary study implemented the ultrafast in-human ULM in various human tissues based on a clinical scanner that supports HFR imaging, indicating the potentials of the technique for various clinical applications. However, rigorous validation of the technique in imaging human microvasculature (especially for those tiny vessel structure), preferably with a gold standard, is still required.

Hypoxia-Related Marker GLUT-1, CAIX, Proliferative Index and Microvessel Density in Canine Oral Malignant Neoplasia.

For various types of tumor therapy, it is suggested that co-targeting of tumor microenvironment, mainly tumor vasculature, mediates tumor response mechanisms. Immunohistochemistry for glucose transporter-1 (GLUT-1), carbonic anhydrase-IX (CAIX), Ki-67, and von Willebrand factor VIII for microvessel density (MVD) were performed on formalin-fixed paraffin-embedded samples of canine oral malignant neoplasms. Polarographic oxygen measurements (median pO2) and perfusion data via contrast-enhanced power Doppler ultrasound (median vascularity, median blood volume) provided additional information. Ninety-two samples were analyzed: sarcomas (n = 32), carcinomas (n = 30), and malignant melanomas (n = 30). Polarographic oxygen and perfusion data was available in 22.8% (sarcomas n = 9, carcinomas n = 7, melanomas n = 5), and 27.1% (sarcomas n = 10, carcinomas n = 8, melanomas n = 7) of cases, respectively. GLUT-1 expression was detected in 46.7% of all samples, and was generally weak. CAIX expression was found in 34.8% of all samples. Median Ki-67 score and MVD count was 19% and 17, respectively. The evaluation of the GLUT-1 score and continuous data showed significantly lower GLUT-1 levels in sarcomas (mean 5.1%, SD 6.2) versus carcinomas and melanomas (mean 16.5%/ 19.0%, SD 17.3/ 20.9, p = 0.001). The expression of CAIX correlated mildly positively with GLUT-1 (p = 0.018, rho = 0.250) as well as with Ki-67 (p = 0.014, rho = 0.295). MVD showed a significantly lower level in melanomas (mean 12.6, SD 7.7) versus sarcomas and carcinomas (mean 21.8/ 26.9, SD 13.0/20.4, p = 0.001). Median vascularity and blood volume were significantly lower in sarcomas (mean 10.4%, SD 11.0, and mean 6.3%, SD 6.5, respectively) versus carcinomas (mean 39.2%, SD 16.4 and mean 33.0%, SD 25.6, respectively) and melanomas (mean 36.0%, SD 18.3, and 31.5%, SD 24.5). Between the 3 histological groups, there was neither a significant difference in the GLUT-1 and CAIX score and continuous data, nor the Ki67 score, or polarographic oxygen measurements. GLUT-1 continuous data and Ki-67 (p<0.001, rho = 0.403), as well as Ki-67 and MVD (p = 0.029, rho = 0.228) correlated positively and a mild correlation was found between vascularity and GLUT-1 (p = 0.043, rho = 0.408). GLUT-1, CAIX, proliferative index and MVD levels were established as microenvironmental descriptors with the purpose of creating a baseline in order to follow changes seen in the tumor microenvironment after hypofractionated radiation with high doses.

Combined perfusion and doppler imaging using plane-wave nonlinear detection and microbubble contrast agents.

Plane-wave imaging offers image acquisition rates at the pulse repetition frequency, effectively increasing the imaging frame rates by up to two orders of magnitude over conventional line-by-line imaging. This form of acquisition can be used to achieve very long ensemble lengths in nonlinear modes such as pulse inversion Doppler, which enables new imaging trade-offs that were previously unattainable. We first demonstrate in this paper that the coherence of microbubble signals under repeated exposure to acoustic pulses of low mechanical index can be as high as 204 ± 5 pulses, which is long enough to allow an accurate power Doppler measurement. We then show that external factors, such as tissue acceleration, restrict the detection of perfusion at the capillary level with linear Doppler, even if long Doppler ensembles are considered. Hence, perfusion at the capillary level can only be detected with ultrasound through combined microbubbles and Doppler imaging. Finally, plane-wave contrast-enhanced power and color Doppler are performed on a rabbit kidney in vivo as a proof of principle. We establish that long pulse-inversion Doppler sequences and conventional wall-filters can create an image that simultaneously resolves both the vascular morphology of veins and arteries, and perfusion at the capillary level with frame rates above 100 Hz.

Application of Contrast-Enhanced Sonography With Time-Intensity Curve Analysis to Explore Hypervascularity in Achilles Tendinopathy by Using a Rabbit Model

The purpose of this study was to investigate the ability of contrast-enhanced sonography in staging and grading hypervascularity in tendinopathic tissues by using a rabbit model. Fourteen rabbits were injected with 100 and 50 μL of collagenase in their left and right Achilles tendons, respectively. The vascularity was assessed by non-contrast-enhanced and contrast-enhanced power Doppler sonography on day 0 (baseline) and days 1, 7, and 14 after collagenase injections. Color pixels within targeted areas were plotted according to time and analyzed by a curve-fitting method. Non-contrast-enhanced power Doppler sonography failed to differentiate vascularity at various stages or between bilateral tendons, whereas contrast-enhanced sonography showed that the peak color pixel amount reached its maximum on day 1 and declined over time in tendons treated with 100 μL of collagenase. A similar trend was observed in tendons receiving 50 μL of collagenase. For comparisons between bilateral tendons, higher vascularity was detected in those treated with more collagenase on day 1 or 7. Time-intensity curve analysis revealed rapid microbubble replenishment in both tendons during their initial phase after collagenase injections. Contrast-enhanced sonography discriminated the vascularity of various injury grades at different time points after collagenase injections. Time-intensity curve analysis detailed the hemodynamics in tendinopathic tissues, which helped differentiate vascularity in acute inflammatory from later degenerative phases.

Value of three‐dimensional contrast‐enhanced power Doppler ultrasound for characterizing adnexal masses

The aim of this study was to assess the diagnostic performance of 3-D contrast-enhanced power Doppler ultrasonography (3-D CEPDUS) for differentiating benign and malignant adnexal masses. Consecutive patients with adnexal masses were included prospectively and underwent 2-D ultrasonography and 3-D CEPDUS in a tertiary centre in Paris, France. The main outcome measure was the diagnostic accuracy of 3-D CEPDUS to diagnose malignant and borderline adnexal masses. The reference standard was the final histological examination. Two-dimensional ultrasonography and 3-D CEPDUS were compared using semiquantitative scores. Three-dimensional CEPDUS assessed vessel density, vessel pattern, and three vascular indexes in a 5-mL region of interest (vascularization index [VI], flow index [FI], and vascularization flow index [VFI]). The 2-D and 3-D examinations were done by different sonographers who were blinded to the other test. The pathologist was blinded to ultrasonography findings. Of 99 patients, 88 had benign tumors and were compared to the 11 patients with borderline (n = 5) or malignant (n = 6) tumors. The sensitivity of the subjective 2-D score was 55% (95% confidence interval [CI], 25-84) and specificity 94% (95%CI, 89-99). The sensitivity of the subjective 3-D score was 82% (95%CI, 58-100) and specificity 90% (95%CI, 83-96). Improvement of detection of malignant or borderline tumors by subjective 3-D score was 150%. Vessel density and patterns were not more efficient than the subjective 3-D score. The mean vascular index values were significantly different between benign and borderline/malignant groups: VI, 7.2 versus 35.5 (P < 0.0001); FI, 37.0 versus 48.2 (P = 0.003); and VFI, 2.9 versus 17.6 (P < 0.0001), respectively. 3-D CEPDUS improves detection of malignant and borderline adnexal masses.

Yield of Contrast-Enhanced Power Doppler Endoscopic Ultrasonography and Strain Ratio Obtained by EUS-Elastography in the Diagnosis of Focal Pancreatic Solid Lesions.

Objective:Although endoscopic ultrasonography-guided fine needle aspiration (EUS-FNA) is the gold standard for diagnosing pancreatic lesions, its negative predictive value is suboptimal. Our aim was to evaluate the yield of contrast-enhanced EUS (CED-EUS) and of strain ratio EUS-elastography (SR-E-EUS) for differentiating pancreatic solid lesions.Methods:Forty-seven patients (27 men, 20 women, 70 ± 11 years) were consecutively involved in this single-center, prospective study. They were submitted to EUS, SR-E-EUS, CED-EUS with Sonovue®, and EUS-FNA. The final diagnosis was based on the histological assessment of EUS-FNA and/or surgical specimens when available, and on follow-up of at least 6 months.Results:From the 47 focal pancreatic lesions included, 13 (28%) were benign and 34 (72%) malignant. Patients with malignancy were older (70 ± 11 vs. 61 ± 8, P = 0.003), and had larger lesions (34 ± 12 mm vs. 22 ± 11 mm, P = 0.03). Malignant lesions had higher SR-E-EUS (31 ± 32 vs. 8 ± 9, P = 0.001) and more hypovascular pattern (93% vs. 33%, P < 0.001). Logistic regression determined that only hypovascularity (OR = 2.6, 95%CI: 1.5-130, P = 0.02) was independently predictive of malignancy. ROC analysis for SR-E-EUS yielded an optimal cutoff of 8 (AUC 0.91, 95%CI: 0.74-0.98) for the best power distinction for malignancy. There was no significant difference concerning sensitivity (79%, 90%, 93%) and specificity rates (85%, 75%, 67%) of EUS-FNA, SR-E-EUS, and CED-EUS, respectively. By analysis of the inconclusive EUS-FNA subset (9 patients, 19%), SR-E-EUS > 8 and hypovascularity showed sensitivity of 80% and 100%, and specificity of 67% and 67%, respectively.Conclusion:The clinical utility of CED-EUS and SR-E-EUS remains questionable. The accuracies of CED-EUS and SR-E-EUS are similar to EUS-FNA. Hypovascularity was independently predictive of malignancy. Patients with inconclusive EUS-FNA could benefit from CED-EUS due to the high sensitivity of hypovascularity for diagnosing malignancy.

Yield of contrast-enhanced power doppler endoscopic ultrasonography and strain ratio obtained by eus-elastography in the diagnosis of focal pancreatic solid lesions

Objective: Although endoscopic ultrasonography-guided fine needle aspiration (EUS-FNA) is the gold standard for diagnosing pancreatic lesions, its negative predictive value is suboptimal. Our aim was to evaluate the yield of contrast-enhanced EUS (CED-EUS) and of strain ratio EUS-elastography (SR-E-EUS) for differentiating pancreatic solid lesions. Methods: Forty-seven patients (27 men, 20 women, 70 ± 11 years) were consecutively involved in this single-center, prospective study. They were submitted to EUS, SR-E-EUS, CED-EUS with Sonovue®, and EUS-FNA. The final diagnosis was based on the histological assessment of EUS-FNA and/or surgical specimens when available, and on follow-up of at least 6 months. Results: From the 47 focal pancreatic lesions included, 13 (28%) were benign and 34 (72%) malignant. Patients with malignancy were older (70 ± 11 vs. 61 ± 8, P = 0.003), and had larger lesions (34 ± 12 mm vs. 22 ± 11 mm, P = 0.03). Malignant lesions had higher SR-E-EUS (31 ± 32 vs. 8 ± 9, P = 0.001) and more hypovascular pattern (93% vs. 33%, P < 0.001). Logistic regression deter­mined that only hypovascularity (OR = 2.6, 95%CI: 1.5-130, P = 0.02) was independently predictive of malignancy. ROC analysis for SR-E-EUS yielded an optimal cutoff of 8 (AUC 0.91, 95%CI: 0.74-0.98) for the best power distinction for malignancy. There was no significant difference concerning sensitivity (79%, 90%, 93%) and specificity rates (85%, 75%, 67%) of EUS-FNA, SR-E-EUS, and CED-EUS, respectively. By analysis of the inconclusive EUS-FNA subset (9 patients, 19%), SR-E-EUS > 8 and hypovas­cularity showed sensitivity of 80% and 100%, and specificity of 67% and 67%, respectively. Conclusion: The clinical utility of CED-EUS and SR-E-EUS remains questionable. The accuracies of CED-EUS and SR-E-EUS are similar to EUS-FNA. Hypovascularity was independently predictive of malignancy. Patients with inconclusive EUS-FNA could benefit from CED-EUS due to the high sensitivity of hypovascularity for diagnosing malignancy.

Power Doppler sonography and ultrasound contrast agent in assessing rheumatoid synovitis

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.

NEW TECHNIQUES AND FUTURE PERSPECTIVE OF EUS FOR THE DIFFERENTIAL DIAGNOSIS OF PANCREATIC MALIGNANCIES: CONTRAST HARMONIC IMAGING

Although endoscopic ultrasonography (EUS) has the advantage over other imaging methods in that it is possible to obtain high resolution images of the pancreas, it is limited in its ability to characterize pancreatic masses. Contrast-enhanced power Doppler ultrasonography suffers from several limitations such as blooming artifacts, poor spatial resolution, low sensitivity to slow flow and high sensitivity to motion artifacts. Recently, EUS system specific for contrast harmonic imaging has been developed. The use of this EUS system enabled us to observe images of microcirculation and parenchymal perfusion without Doppler-related artifacts in the pancreas. Contrast-enhanced harmonic EUS could diagnose pancreatic carcinomas as hypovascular masses with a high sensitivity (89-96%) and specificity (64-88%). Contrast-enhanced harmonic EUS also discriminates mural nodules from mucous clots in the intraductal papillary mucinous neoplasms.

Results of Vardenafil Mediated Power Doppler Ultrasound, Contrast Enhanced Ultrasound and Systematic Random Biopsies to Detect Prostate Cancer

We evaluated the ability of the phosphodiesterase-5 inhibitor vardenafil to increase prostate microcirculation during power Doppler ultrasound. We also evaluated the results of contrast and vardenafil enhanced targeted biopsies compared to those of standard 12-core random biopsies to detect cancer. Between May 2008 and January 2010, 150 consecutive patients with prostate specific antigen more than 4 ng/ml at first diagnosis with negative digital rectal examination and transrectal ultrasound, and no clinical history of prostatitis underwent contrast enhanced power Doppler ultrasound (bolus injection of 2.4 ml SonoVue® contrast agent), followed by vardenafil enhanced power Doppler ultrasound (1 hour after oral administration of vardenafil 20 mg). All patients underwent standard 12-core transrectal ultrasound guided random prostate biopsy plus 1 further sampling from each suspected hypervascular lesion detected by contrast and vardenafil enhanced power Doppler ultrasound. Prostate cancer was detected in 44 patients (29.3%). Contrast and vardenafil enhanced power Doppler ultrasound detected suspicious, contrast enhanced and vardenafil enhanced areas in 112 (74.6%) and 110 patients (73.3%), and was diagnostic for cancer in 32 (28.5%) and 42 (38%), respectively. Analysis of standard technique, and contrast and vardenafil enhanced power Doppler ultrasound findings by biopsy core showed significantly higher detection using vardenafil vs contrast enhanced power Doppler ultrasound and standard technique (41.2% vs 22.7% and 8.1%, p <0.005 and <0.001, respectively). The detection rate of standard plus contrast or vardenafil enhanced power Doppler ultrasound was 10% and 11.7% (p not significant). Vardenafil enhanced power Doppler ultrasound enables excellent visualization of the microvasculature associated with cancer and can improve the detection rate compared to contrast enhanced power Doppler ultrasound and the random technique.

Mo1511 Feasibility Study of Tridimensional Co-Registration of Endoscopic Ultrasound and Dynamic Spiral Computer Tomography Procedures for Real-Time Evaluation of Tumor Angiogenesis

Mo1511 Feasibility Study of Tridimensional Co-Registration of Endoscopic Ultrasound and Dynamic Spiral Computer Tomography Procedures for Real-Time Evaluation of Tumor Angiogenesis

CONTRAST-ENHANCED HARMONIC ULTRASONOGRAPHY OF MEDIAL ILIAC LYMPH NODES IN HEALTHY DOGS

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.

Combined contrast-enhanced power Doppler and real-time sonoelastography performed during EUS, used in the differential diagnosis of focal pancreatic masses (with videos)

Contrast-enhanced power Doppler (CEPD) and real-time sonoelastography (RTSE) performed during EUS were previously described to be useful for the differential diagnosis between chronic pseudotumoral pancreatitis and pancreatic cancer. To prospectively assess the accuracy of the combination of CEPD and RTSE to differentiate pancreatic focal masses. Cross-sectional feasibility study. A tertiary-care academic referral center. The study group included 54 patients with chronic pancreatitis (n = 21) and pancreatic adenocarcinoma (n = 33). Both imaging methods (CEPD and RTSE) were performed sequentially during the same EUS examination. Power Doppler mode examination was performed after intravenous injection of a second-generation contrast agent (2.4 mL of SonoVue), and the data were digitally recorded, comprising both the early arterial phase and venous/late phase. Three 10-second sonoelastographic videos were also digitally recorded that included the focal mass and the surrounding pancreatic parenchyma. Postprocessing analyses based on specially designed software were used to analyze the CEPD and RTSE videos. A power Doppler vascularity index was used to characterize CEPD videos, the values being averaged during a 10-second video in the venous phase. Hue histogram analysis was used to characterize RTSE videos, with the mean hue histogram values being also averaged during a 10-second video. To differentiate chronic pancreatitis and pancreatic cancer. The sensitivity, specificity, and accuracy of combined information provided by CEPD and RTSE to differentiate hypovascular hard masses suggestive of pancreatic carcinoma were 75.8%, 95.2%, and 83.3%, respectively, with a positive predictive value and negative predictive value of 96.2% and 71.4%, respectively. A single-center, average size of study population. A combination of CEPD and RTSE performed during EUS seems to be a promising method that allows characterization and differentiation of focal pancreatic masses.

CONTRAST-ENHANCED ULTRASOUND OF THE FELINE KIDNEY

Contrast-enhanced ultrasound offers a noninvasive means of subjectively and quantitatively evaluating renal perfusion in cats with renal disease, or in renal transplant patients. In this study, we characterized the pattern of ultrasonographic contrast enhancement in 16 normal feline kidneys in eight cats using contrast-enhanced power Doppler and contrast-enhanced harmonic ultrasound techniques. Mean time to peak contrast enhancement for the whole kidney was longer using contrast-enhanced harmonic ultrasound (16.8s, SD 4.7s) than contrast-enhanced power Doppler ultrasound (12.2s, SD 1.8s). The time to peak enhancement for the cortex alone in contrast-enhanced harmonic ultrasound was 13s (SD 3.2s), and for the renal medulla was 25.5s (SD 8.7s). The half time for washout of contrast agent was 39s (SD 14.5s) for contrast-enhanced harmonic ultrasound. The pattern of contrast enhancement in these normal feline kidneys can be used as normal reference values for the evaluation of clinical patients. Contrast-enhanced harmonic ultrasound may allow the differentiation between cortical and medullary perfusion patterns.

Correlation of Pretreatment Polarographically Measured Oxygen Pressures with Quantified Contrast-Enhanced Power Doppler Ultrasonography in Spontaneous Canine Tumors and their Impact on Outcome After Radiation Therapy

To evaluate the use of noninvasive quantified contrast-enhanced power Doppler ultrasonography as a surrogate in the estimation of tumor hypoxia measured by invasive pO(2) histography in canine tumors. Data of pretreatment tumor oxygenation status, tumor vascularity and blood volume, and tumor response after radiation therapy was collected in 48 spontaneous malignant oral tumors (Table 1). Tumor oxygenation status was correlated to vascularity and blood volume, and influences on outcome after treatment were analyzed. Although vascularity and blood volume correlated moderately with median pO(2) (r = 0.51 and 0.61; p = 0.001 and < 0.0001) and percentage of pO(2) readings < or = 2.5, 5, and 10 mmHg (r = -0.37 to -0.42; p < 0.01-0.03) for all tumors, they did not correlate within the different histology groups (p = 0.06-0.9). For all tumors, pretreatment oxygenation status, vascularity and blood volume were not found to be of prognostic value (Tables 2 and 3). These analyses show that quantified contrast-enhanced power Doppler ultrasonography does not represent a noninvasive indirect method to assess tumor hypoxia measured by invasive pO(2) histography. Both technologies were nonprognostic indicators in spontaneous malignant canine oral tumors.

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

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.

0470: Ultrasound in Crohns Disease

High-resolution ultrasonography has greatly improved the diagnostic potential of ultrasound in the assessment of inflammatory bowel disease. Ultrasonography is not only a method used by radiologists, but also a clinical tool that can be applied to evaluate patients with Crohn's disease: both for bed-side tentative diagnosis, pre-operative scanning, and for out-patient follow-up. This lecture reviews some of the principles, common findings and methods that can be used in ultrasonographic scanning of the GI tract in patients with Crohn's disease. Ultrasound of the GI tract has proved to be useful as an imaging modality in patients with symptoms or clinical signs that indicate inflammatory bowel disorder as well as for assessing the anatomical extension of Crohn's lesions at primary diagnosis. Mb. Crohn often starts with symptoms like abdominal pain, diarrhoea or weight loss. Ultrasonography is a very relevant method to rule out different causes of these symptoms and to detect changes compatible with Crohn's disease. A normal bowel wall is considered to have a wall thickness below 2-4mm, depending on the actual localisation. Typical ultrasound findings in Crohn's disease are: Increased GI-wall thickness most often seen in the distal ileum, dilated bowel loops, ulcerations or fistulas, abscesses, reduced motility, decreased Resistive Index, and in some cases ascites. In some cases, full endoscopic examination is not possible due to a stenotic GI segment, e.g. of the colon or pyloric ulceration leading to gastric retention. In such circumstances, transabdominal ultrasound can image the more central part of the intestines and give valuable information about the length of the stenotic part. Ultrasonic determination of the extent of the GI-wall affection will also aid in distinguishing between ulcerative colitis and Crohn's disease. Another indication is the ambulant follow-up of patients who have established Crohn's disease. High-frequency ultrasonography may play a key role in the detection of luminal and mesentery complications or for the evaluation of disease extension during a clinical flare-up. The patients can act as their own controls over time and the effect of treatment can be monitored by ultrasonography. The role of bowel ultrasound in the assessment of disease activity is controversial, but the use of Doppler RI and i.v. contrast agents has the potential to differentiate inflammatory from fibrotic intestinal strictures. Contrast-enhanced power Doppler ultrasound has high sensitivity and specificity in the detection and evaluation of inflammatory abdominal masses associated with Crohn's disease, and compares favourably with computed tomography. The spatial resolution and sensitivity of contrast-enhanced power Doppler ultrasound enables the detection of small inflammatory abdominal masses. The absence of radiation dose to the patient allows multiple and serial examinations to be undertaken. In conclusion, ultrasonography is a very useful clinical tool in the management of patients with Crohn's disease. New ultrasound technologies, such intravenous contrast agents, advanced Doppler methods, and elastography may further increase the diagnostic capability of GI ultrasonography.

Acute Increases in Murine Tumor Echogenicity After Antivascular Ultrasound Therapy

This study was designed to determine whether the echogenicity of neoplastic tissues changed as a result of low-intensity insonation and whether such alterations were related to an anti-vascular effect. In 21 mice, implanted melanomas were insonated at either 1, 2, or 3 MHz using low-intensity ultrasound (spatial-average temporal-average intensity, 2.1 W/cm(2)). B-mode (mean gray scale) and contrast-enhanced power Doppler (percentage area of flow) measurements were made on each tumor before and after therapy. There was an increase in the echogenicity of the tumors with the increase in the frequency of the therapy beam and an accompanying decrease in tumor vascularity. Although the mechanisms responsible for the echogenicity change are not fully understood, it appears that an increase in the tumor mean gray scale was, at least in part, related to tissue inhomogeneities formed after disruption of the tumor neovasculature.

Contrast-Enhanced Power Doppler Endoscopic Ultrasound Used for the Differential Diagnosis of Chronic Pancreatitis and Pancreatic Cancer

Contrast-Enhanced Power Doppler Endoscopic Ultrasound Used for the Differential Diagnosis of Chronic Pancreatitis and Pancreatic Cancer

Follow-up of a self-resolving renal pseudoaneurysm using contrast-enhanced power Doppler ultrasonography

It has been standard practice to embolise a pseudoaneurysm caused by penetrating trauma whenever it is found, even in the absence of overt symptoms. This is a case report of...