D-galactose-based signal-enhanced color Doppler sonography of breast tumors and tumorlike lesions

Diagnostic value of a power Doppler ultrasound-based malignancy index for differentiating malignant and benign solid breast lesions

Background

Power Doppler ultrasound (PDUS) can provide useful information regarding the vascularity of breast lesions. The aim of this study was to investigate the diagnostic performance of a new PDUS-driven malignancy index in differentiating between malignant and benign causes of solid breast lesions.

Materials and Methods

Patients with solid breast lesions were enrolled consecutively and evaluated first by PDUS and subsequently by histopathologic assessment after undergoing surgical biopsy. A custom-made software was used to extract data from images for calculating malignancy index formula.

Results

A total of 87 patients with solid breast lesions were enrolled. Histopathologic evaluation identified 49 patients as benign and 38 patients as malignant. Malignancy index was significantly higher in the malignant group as compared to benign tumors (6.31 vs 0.30,P < 0.001). Area under the receiver operating characteristics (ROC) curve (AUC) was 0.98 (95% confidence interval (CI) 0.95-1.00). According to the ROC curve analysis, the cut-off point of 1.23 for malignancy index had a sensitivity and specificity of 94.7% (95% CI 82.2-99.3) and 94.0% (95% CI 83.1-98.7), respectively.

Conclusion

Comparing with the histopathologic evaluation as the gold standard for diagnosing breast lesions, PDUS-driven malignancy index was shown to have a high discriminative performance in identifying malignant lesions with high sensitivity, specificity, and diagnostic accuracy. The noninvasive nature of PDUS is an important advantage that could prevent unnecessary biopsies.

Diagnostic Value of Contrast-Enhanced Sonography for Differentiation of Breast Lesions: A Meta-analysis

OBJECTIVES

The purpose of this study was to systematically review and evaluate the diagnostic accuracy of contrast-enhanced sonography in the differential diagnosis of benign and malignant breast lesions.

METHODS

The scientific literature databases PubMed and Embase were comprehensively searched for relevant studies before January 2015. Data were pooled to yield the summary sensitivity, specificity, and diagnostic odds ratio using meta-analysis software.

RESULTS

A total of 29 studies with 2296 lesions were included in the analysis. The pooled sensitivity and specificity were 0.88 (95% confidence interval [CI], 0.86-0.90; inconsistency index [I(2)] = 77.9%) and 0.80 (95% CI, 0.78-0.83; I(2) = 84.0%), respectively. The pooled diagnostic odds ratio was 30.35 (95% CI, 15.75-58.48; I(2)= 82.1%), and the area under the summary receiver operating characteristic curve was 0.9115 (SE, 0.0243).

CONCLUSIONS

The comprehensive results suggest that contrast-enhanced sonography could be a potentially effective method for differential diagnosis of benign and malignant breast lesions.

Diagnosis of solid breast tumors using vessel analysis in three-dimensional power Doppler ultrasound images

This study aims to evaluate whether the distribution of vessels inside and adjacent to tumor region at three-dimensional (3-D) power Doppler ultrasonography (US) can be used for the differentiation of benign and malignant breast tumors. 3-D power Doppler US images of 113 solid breast masses (60 benign and 53 malignant) were used in this study. Blood vessels within and adjacent to tumor were estimated individually in 3-D power Doppler US images for differential diagnosis. Six features including volume of vessels, vascularity index, volume of tumor, vascularity index in tumor, vascularity index in normal tissue, and vascularity index in surrounding region of tumor within 2 cm were evaluated. Neural network was then used to classify tumors by using these vascular features. The receiver operating characteristic (ROC) curve analysis and Student's t test were used to estimate the performance. All the six proposed vascular features are statistically significant (p < 0.001) for classifying the breast tumors as benign or malignant. The A Z (area under ROC curve) values for the classification result were 0.9138. Accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of the diagnosis performance based on all six proposed features were 82.30 (93/113), 86.79 (46/53), 78.33 (47/60), 77.97 (46/59), and 87.04 % (47/54), respectively. The p value of A Z values between the proposed method and conventional vascularity index method using z test was 0.04.

Color Doppler ultrasonography evaluation for chemotherapy treatment response of osteogenic sarcoma

The aim of this study was to evaluate the vascular parameters of the proximal peripheral arteries of limbs by color Doppler ultrasonography (CDUS) in individuals with osteogenic sarcoma (OGS) after neoadjuvant chemotherapy and their relation to the tumor necrosis rate. We recruited 50 individuals with osteogenic sarcoma who were scheduled for neoadjuvant chemotherapy before elective surgery from 2003 to 2010. Once enrolled, we evaluated these 50 subjects using color Doppler sonography to identify vascular parameters of tumor vessels before and after neoadjuvant therapy. The vascular parameters of the proximal peripheral arteries of limbs (peak systolic velocity [PSV], end-diastolic velocity [EDV], resistive index [RI]) and tumor neovascularity were compared before and after neoadjuvant chemotherapy using CDUS. Before chemotherapy, the PSV, EDV and RI differed significantly between the diseased and contralateral normal limbs (p < 0.001). Among the factors relating to the tumor necrosis rate before chemotherapy, the EDV of the diseased limb (p = 0.047) and tumor neovascularity (p = 0.027) showed significant differences. After chemotherapy, the PSV of the diseased limb (p = 0.022) and the difference in PSV between the diseased and contralateral limbs (p = 0.003) showed significant differences. The vascular parameters of the proximal peripheral arteries of limbs owing to tumor burden differ significantly between the diseased and contralateral normal limbs. For individuals with osteogenic sarcoma who still have a higher difference in PSV between the diseased and contralateral limbs after chemotherapy, another course of chemotherapy after surgery and close follow-up should be considered.

Soft-tissue tumor differentiation using 3D power Doppler ultrasonography with echo-contrast medium injection

BACKGROUND

We aimed to evaluate the ability of 3-dimensional power Doppler ultrasonography to differentiate soft-tissue masses from blood flow and vascularization with contrast medium.

METHODS

Twenty-five patients (mean age, 44.1 years; range, 12-77 years) with a palpable mass were enrolled in this study. Volume data were acquired using linear and convex 3-dimensional probes and contrast medium injected manually by bolus. Data were stored and traced slice by slice for 12 slices. All patients were scanned by the same senior sonologist. The vascular index (VI), flow index (FI), and vascular-flow index (VFI) were automatically calculated after the tumor was completely traced. All tumors were later confirmed by pathology.

RESULTS

The study included 8 benign (mean, 36.5 mL; range, 2.4-124 mL) and 17 malignant (mean, 319.4 mL; range, 9.9-1,179.6 mL) tumors. Before contrast medium injection, mean VI, FI and VFI were, respectively, 3.22, 32.26 and 1.07 in benign tumors, and 1.97, 29.33 and 0.67 in malignant tumors. After contrast medium injection, they were, respectively, 20.85, 37.33 and 8.52 in benign tumors, and 40.12, 41.21 and 17.77 in malignant tumors. The mean differences between with and without contrast injection for VI, FI and VFI were, respectively, 17.63, 5.07 and 7.45 in benign tumors, and 38.15, 11.88 and 16.55 in malignant tumors. Tumor volume, VI, FI and VFI were not significantly different between benign and malignant tumors before and after echo-contrast medium injection. However, VI, FI and VFI under self-differentiation (differences between with and without contrast injection) were significantly different between malignant and benign tumors.

CONCLUSION

Three-dimensional power Doppler ultrasound is a valuable tool for differential diagnosis of soft-tissue tumors, especially with the injection of an echo-contrast medium.

Microvascular architecture of breast lesions: evaluation with contrast-enhanced ultrasonographic micro flow imaging

OBJECTIVE

The purpose of this study was to evaluate the effectiveness of micro flow imaging (MFI) of the microvascular architecture with contrast-enhanced ultrasonography for classification of breast lesions as benign or malignant and the microvascular architectural patterns.

METHODS

Contrast-enhanced ultrasonography and MFI were performed in 61 women with breast lesions. The microvascular morphologic and distribution features of the breast tumors were evaluated with MFI. Receiver operating characteristic curve analysis was used to evaluate the diagnostic value of MFI, and the microvascular architectural patterns were analyzed.

RESULTS

Surgical pathologic analysis showed 29 benign and 32 malignant lesions. For MFI, the area under the receiver operating characteristic curve (A(z)) value for the overall features of the blood vessels for classification of breast lesions was 0.94. The accuracy, sensitivity, and specificity were 90.2% (55/61), 93.8% (30/32), and 86.2% (25/29), respectively. The A(z) value for the morphologic and distribution features of peripheral blood vessels was 0.91, which was significantly higher than the A(z) value for the morphologic and distribution features of interior vessels (P= .019). The microvascular architecture of the 61 lesions was categorized into 3 patterns: treelike, root hair-like, and crab claw-like. Benign lesions mainly displayed the treelike pattern (17 [58.6%]); malignant lesions tended to display the crab claw-like pattern (20 [62.5%]); and the root hair-like pattern was shown in both benign and malignant lesions (11 [37.9%] and 8 [25%], respectively). The microvascular architecture showed significant differences between benign and malignant lesions (P< .001).

CONCLUSIONS

Micro flow imaging can clearly delineate the microvascular architecture of breast lesions and can aid in discrimination between benign and malignant breast lesions.

Solid breast masses: neural network analysis of vascular features at three-dimensional power Doppler US for benign or malignant classification

PURPOSE

To retrospectively evaluate the accuracy of neural network analysis of tumor vascular features at three-dimensional (3D) power Doppler ultrasonography (US) for classification of breast tumors as benign or malignant, with histologic findings as the reference standard.

MATERIALS AND METHODS

This study was approved by the local ethics committee; informed consent was waived. Three-dimensional power Doppler US images of 221 solid breast masses (110 benign, 111 malignant) were obtained in 221 women (mean age, 46 years; range, 25-71 years). After narrowing down vessels to skeletons with a 3D thinning algorithm, six vascular feature values--vessel-to-volume ratio, number of vascular trees, total vessel length, longest path length, number of bifurcations, and vessel diameter-were computed. A neural network was used to classify tumors by using these features. Independent-samples t test and receiver operating characteristic (ROC) curve analysis were used.

RESULTS

Mean values of vessel-to-volume ratio, number of vascular trees, total vessel length, longest path length, number of bifurcations, and vessel diameter were 0.0089 +/- 0.0073 (standard deviation), 26.41 +/- 14.73, 23.02 cm +/- 19.53, 8.44 cm +/- 10.38, 36.31 +/- 37.06, and 0.088 cm +/- 0.021 in malignant tumors, respectively, and 0.0028 +/- 0.0021, 9.69 +/- 6.75, 5.17 cm +/- 4.78, 1.68 cm +/- 1.79, 6.05 +/- 7.55, and 0.064 cm +/- 0.028 in benign tumors, respectively (P < .001 for all six features). Area under ROC curve (A(z)) values of the six features were 0.84, 0.87, 0.87, 0.82, 0.84, and 0.75, respectively. Accuracy, sensitivity, specificity, and positive and negative predictive values were 85% (187 of 221), 83% (96 of 115), 86% (91 of 106), 86% (96 of 111), and 83% (91 of 110), respectively, with A(z) of 0.92 based on all six feature values.

CONCLUSION

Three-dimensional power Doppler US images and neural network analysis of features can aid in classification of breast tumors as benign or malignant.

Applications of Doppler Imaging in the Musculoskeletal System

Pathological conditions affecting the musculoskeletal system often result in alterations of regional blood flow. The assessment of a Doppler signal in inflammatory or infective processes complements the grayscale findings, helping to evaluate the severity of disease. Doppler imaging can also be used to determine therapeutic response or help guide injections. In addition, Doppler interrogation enables vascular characterization of solid masses. The presence of a Doppler signal can also help differentiate solid from cystic lesions. This article reviews the wide range of applications for Doppler imaging of the musculoskeletal system.

Computer-assisted quantitative assessment of power Doppler US: effects of microbubble contrast agent in the differentiation of breast tumors

RATIONALE AND OBJECTIVES

To objectively quantify the effects of a microbubble contrast agent to differentiate breast tumors with power doppler ultrasound and to compare these results with color doppler ultrasound (CD US).

METHODS

In 47 patients a microbubble contrast agent was injected intravenously. Computer-assisted quantitative assessment of the color pixel density was performed to evaluate the increase in Doppler signals. Results were compared to previously published results of a color Doppler ultrasound study.

RESULTS

Peak color pixel density at contrast-enhanced power Doppler ultrasound was higher for carcinomas than for benign tumors (P < 0.03). Time to peak enhancement was shorter in carcinomas than in benign tumors (P < 0.01). For both parameters, diagnostic accuracy of power Doppler ultrasound was 69 and 78%, and for color Doppler ultrasound 62 and 76%, respectively.

CONCLUSIONS

Quantitative assessment of contrast-enhanced power Doppler ultrasound showed significant differences in malignant and benign breast tumors. Diagnostic accuracy of contrast-enhanced power Doppler ultrasound was higher compared to color Doppler ultrasound.

Power Doppler sonography of invasive breast carcinoma: does tumor vascularization contribute to prediction of axillary status?

PURPOSE

To prospectively compare unenhanced power Doppler sonographic findings of arterial vascularization of invasive breast carcinoma with histopathologic and immunohistochemical parameters and to determine whether tumor arterial vascularization contributes to prediction of axillary node status.

MATERIALS AND METHODS

Ethics committee approval and informed consent were obtained. A total of 97 invasive breast carcinomas were prospectively studied with unenhanced power Doppler sonography before surgery. Lumpectomy or mastectomy with full axillary nodal dissection was performed. Sonographic tumor size and number of tumor arteries were correlated with axillary nodal status by means of logistic regression analysis. Tumor microvascularization was immunohistochemically assessed in a subset of 55 carcinomas. Sonographic variables were correlated with tumor arteries with a diameter larger than 300 mum and with the density and area of microvascularization. The kappa statistic and Bland-Altman agreement limits were used to measure agreement between techniques.

RESULTS

Good agreement of sonographic and histologic findings regarding number of tumor arteries (kappa= 0.66, P < .001) and tumor size (P = .012) was observed. Multivariate analysis showed an independent relationship between probability of axillary metastasis, number of tumor arteries (P = .016), and sonographic tumor size (P = .035). A predictive model of axillary status was developed. The receiver operating characteristic curve was used to determine 0.2324 as the score to classify axillary nodal status. This score indicated high sensitivity (96.1%), low specificity (53.0%), and high negative predictive value (96.1%).

CONCLUSION

The number of arteries in invasive breast carcinoma detected with unenhanced power Doppler sonography and sonographic tumor size are independent predictors of axillary nodal status; these variables could contribute to reliable prediction of absence of axillary involvement on the basis of a mathematic model.

Contrast-enhanced power Doppler sonography in breast lesions: effect on differential diagnosis after mammography and gray scale sonography

OBJECTIVE

To evaluate the efficacy of contrast-enhanced power Doppler sonography in the differential diagnosis of breast lesions after a mammography-gray scale sonography combination.

METHODS

Sixty-eight patients with 69 breast masses underwent power Doppler sonography before and after intravenous injection of a contrast agent. The lesions were diagnosed as "highly suggestive of malignancy" (category 5; n = 32), "suspicious" (category 4; n = 21), and "probably benign" (category 3; n = 16) by mammography and gray scale sonography, modeled on the American College of Radiology Breast Imaging Reporting and Data System classification. Power Doppler findings did not affect patient treatment. The authors subjectively evaluated the estimated area of vascularity, degree of enhancement following contrast agent administration, morphologic features, and distribution of vessels within the lesions.

RESULTS

The final diagnoses were malignant in 28 lesions and benign in 41. Significant enhancement after contrast agent injection was detected in both the malignant and benign groups. Only 2 criteria, estimated area of vascularity and degree of enhancement following contrast agent administration, proved to be significant diagnostic determinants for contrast-enhanced power Doppler sonography (P < .001; interobserver agreements, 74.4 and 77.8, respectively). Contrast-enhanced power Doppler sonography provided a higher specificity, positive predictive value, and negative predictive value than power Doppler sonography but a lower sensitivity and negative predictive value than mammography-gray scale sonography. Only in the category 4 lesions could the combination of mammography-gray scale sonography and contrast-enhanced power Doppler sonography accomplish a higher specificity (71%) and positive predictive value (70%) than mammography-gray scale sonography (39% and 53%, respectively).

CONCLUSIONS

Power Doppler and contrast-enhanced power Doppler sonography cannot be recommended as confirmatory tests in Breast Imaging Reporting and Data System category 3 and category 5 lesions. Although contrast-enhanced power Doppler sonography may help reduce unnecessary biopsies in Breast Imaging Reporting and Data System category 4 lesions, recommendation of its use has many drawbacks, such as imperfectly established criteria, lack of absolute certainty, and high cost.

Spectral Doppler sonography of musculoskeletal soft tissue masses

OBJECTIVE

To determine whether resistive indices obtained from spectral Doppler waveforms can be used to distinguish benign from malignant musculoskeletal soft tissue masses.

METHODS

A retrospective review of Doppler sonograms was performed for 52 patients with 53 soft tissue masses. All masses showed internal flow on color or power Doppler sonography, and spectral Doppler sonography yielded waveforms from which resistive indices were calculated. This information was analyzed along with the histologic diagnosis of each lesion with significance set at P > .05.

RESULTS

There were 19 benign lesions and 34 malignancies. The resistive indices of the benign masses ranged from 0.44 to 1.0 (mean +/- SD, 0.72 +/- 0.42), whereas the malignant masses had resistive indices ranging from 0.28 to 1.0 (mean, 0.62 +/- 0.36). There was no statistically significant (P > .05) difference between the resistive indices of benign and malignant lesions.

CONCLUSIONS

Resistive indices cannot be used to distinguish benign from malignant musculoskeletal soft tissue masses.

Value of contrast-enhanced power Doppler sonography using a microbubble echo-enhancing agent in evaluation of small breast lesions

PURPOSE

The purpose of this study was to prospectively evaluate the usefulness of contrast-enhanced power Doppler sonography (PDUS) using a microbubble echo-enhancing agent in differentiating between malignant and benign small breast lesions.

PATIENTS AND METHODS

Between July 1, 2000, and September 30, 2001, we performed gray-scale sonographic examination of patients in whom diagnostic sonography or screening mammography had revealed solid breast lesions measuring less than 2 cm in the largest dimension. The patients were then examined on PDUS before and after injection of a microbubble contrast agent. The sonographic findings for all 3 techniques, as well as the morphologic features of the Doppler signals for each patient before and after injection of the contrast agent on PDUS, were independently assessed. Each lesion was classified as "benign" or "malignant" on the basis of specific criteria for sonographic interpretation. A hemodynamic study was performed in which time-transit profiles of the Doppler signals on contrast-enhanced PDUS were generated using a computer-assisted program, and the results for each patient were compared with the findings of a histopathologic examination of surgical specimens.

RESULTS

Thirty-six patients (35 women and 1 man) with a mean age of 43.5 years (range, 18-69 years) were evaluated. The tumors ranged from 4 to 19 mm in the largest dimension. Histopathologic examination revealed that 19 tumors were benign and 17 were malignant. For morphologic diagnosis of the malignant lesions, the sensitivity of gray-scale sonography was 100%, compared with 29% for PDUS without contrast enhancement. The specificity of gray-scale sonography was 47%, compared with 74% for PDUS without contrast enhancement. Contrast-enhanced PDUS had a sensitivity of 71% and a specificity of 58%. The diagnostic accuracy was 72% for gray-scale sonography, 53% for PDUS without contrast enhancement, and 64% for contrast-enhanced PDUS. The time-transit profiles of the hemodynamic study did not reveal a statistically significant difference in the accuracy rates of contrast-enhanced PDUS between benign and malignant breast lesions.

CONCLUSIONS

Compared with PDUS without contrast enhancement, contrast-enhanced PDUS provides better visualization of the morphology of vascular Doppler signals that is characteristic of malignancy and therefore has a higher sensitivity and diagnostic accuracy, albeit a lower specificity. In differentiating between benign and malignant small breast lesions, contrast-enhanced PDUS can be helpful when used with gray-scale sonography and PDUS without contrast enhancement.

Tissue oxygenation and perfusion in inferior pedicle reduction mammaplasty by near-infrared reflection spectroscopy and color-coded duplex sonography

Near-infrared reflection spectroscopy has been used in various experimental and clinical settings to investigate tissue perfusion and oxygenation noninvasively. Its application in plastic surgery has only recently been reported. The current study used near-infrared reflection spectroscopy to monitor cutaneous microcirculation in breast skin flaps after inferior pedicle reduction mammaplasty. Thirty patients underwent bilateral reduction mammaplasty by a modified Robbins technique. Near-infrared reflection spectroscopy measurements were performed preoperatively and postoperatively at several defined positions of the breast. The reflection spectroscopy system was capable of detecting absolute values of total hemoglobin in milligrams per milliliter of tissue and tissue hemoglobin oxygen saturation in percent. Color-coded duplex sonography was used to visualize nutrient vessels of the inferior dermoglandular pedicle and to measure systolic peak flow in the arteries supplying the nipple-areola complex. Reflection spectroscopy values were examined for changes during the postoperative course. Reflection spectroscopy and duplex sonography values were analyzed for differences between patients with normal and compromised skin flap perfusion and wound healing, which was assessed clinically and by ultrasound. Preoperative reflection spectroscopy values demonstrated local, regional, and interindividual variations. Postoperatively, characteristic changes of tissue hemoglobin oxygen saturation and total hemoglobin were observed in all patients during the 2-week follow-up. Reflection spectroscopy values differed significantly between breast and nipple-areola skin. Tissue hemoglobin oxygen saturation was significantly lower, and total hemoglobin significantly higher, in patients with impaired wound healing compared with patients having normal wound healing. However, systolic peak flow in arteries of the inferior dermoglandular pedicle did not reveal differences between patients with impaired or normal wound healing of the nipple-areola complex. Near-infrared reflection spectroscopy allows the detection of hemoglobin content and oxygenation in skin flaps. Changes in tissue hemoglobin oxygen saturation and total hemoglobin reflect hemodynamic changes in skin flaps during normal and pathological wound healing. Because of considerable intraindividual and interindividual variations, trend values seem to be superior to single measurements. Although in this study, near-infrared reflection spectroscopy was capable of distinguishing between normal and impaired perfusion in skin flaps in a clinical model, its future implication may be the early detection of vascular compromise in free flaps.

Differentiation of malignant and benign musculoskeletal tumors: combined color and power Doppler US and spectral wave analysis

PURPOSE

To assess the use of combined color Doppler ultrasonography (US), power Doppler US, and spectral wave analysis (SWA) in differentiating malignant and benign musculoskeletal tumors.

MATERIALS AND METHODS

Seventy-nine musculoskeletal tumors (34 malignant, 45 benign) were examined with color and power Doppler US and SWA. Two radiologists independently assessed US images and SWA findings. Echotexture and vessel characteristics such as stenoses, occlusions, loops, shunts, trifurcations, vascular pattern, and resistive index were evaluated. All tumors were subject to US-guided or open biopsy for histologic correlation.

RESULTS

Combined color and power Doppler US and SWA revealed four major (stenosis, occlusion, trifurcation, vascular pattern) and three minor (shunt, self loop, resistive index) vessel characteristics, which proved helpful in differentiating benign from malignant lesions. Echotexture showed moderate sensitivity (82% [28 of 34 tumors]) and low specificity (38% [17 of 45 tumors]). When comparing several combinations of vessel characteristics, a combination of any two major characteristics demonstrated the best results (sensitivity, 94% [33 of 39 tumors]; specificity, 93% [three of 45 tumors]). Combining more than two characteristics resulted in lower sensitivity.

CONCLUSION

Combined color and power Doppler US and SWA may enable assessment of vascular architecture and altered flow of musculoskeletal tumors. Vascular architecture analysis enables differentiation of benign and malignant lesions and evaluation of musculoskeletal tumors.

Tumor vascularization in experimental melanomas: correlation between unenhanced and contrast enhanced power Doppler imaging and histological grading

The purpose of this study was to evaluate the reliability of unenhanced and enhanced power Doppler sonography in visualization of intratumoral angioneogenesis. Thirty-seven malignant melanomas, which had been implanted intra- or subcutaneously in 22 mice, were examined. Various B-mode criteria, power Doppler criteria and spectral Doppler parameters were evaluated before and after IV-application of the d-galactose-based contrast agent Levovist. After sonographic examination, all tumors were analyzed histologically with semiquantitative grading of tumoral vascularization. Unenhanced, in 70% of the tumors, no intratumoral vessels were visible using power Doppler, but only in 11% of the intracutaneous and in 0% of the subcutaneous after injection of the contrast agent. The enhanced mode was definitely superior to unenhanced Doppler in showing the intratumoral vascularity. The intratumoral vascular structure could be sufficiently analyzed in 30% of all tumors by unenhanced Doppler, but in 92% enhanced. The mean percentage vessel area increased about 433% after application of Levovist (intracutaneous: 485%, subcutaneous: 280%). Despite the missing direct correlation between the sonographically and histologically determined grade of tumor vascularization (Pearson's correlation unenhanced 0,356, p <.05/enhanced 0.395, p <.05), the correlation between the percentage vessel area and the histologic grade of vascularization was improved after application of the contrast agent (Pearson's correlation unenhanced 0.347, p <.05/enhanced 0.686, p <.01). We did not find a significant direct correlation between histologically and sonographically determined degree of vascularization. However, the correlation was improved using a d-galactose-based signal-enhancing agent in power Doppler sonography.

A review of contrast media research in 1999-2000

Contrast media research published during the years 1999 and 2000 is reviewed in this article, in terms of relevance to developments within the field of diagnostic radiology. The primary focus is on publications from the journal Investigative Radiology, which publishes much of the clinical and laboratory research performed in this field. The journals Radiology and the American Journal of Roentgenology are dominant in the field of diagnostic radiology and together publish more than 10 times the number of articles as appear each year in Investigative Radiology. However, in 1999 for example, these two journals together published fewer articles than did Investigative Radiology alone that concerned basic (animal) research with contrast media. Thirty-six percent of the articles in Investigative Radiology in 1999 had a primary focus on contrast media and 18% on basic (animal) research with contrast media. To make this review more complete, articles from other major journals are cited and discussed, as needed, to provide supplemental information in the few areas not well covered by articles in Investigative Radiology. The safety of contrast media is always an important topic and research continues to be performed in this area, both to explore fundamental issues regarding iodinated contrast media and also to establish the overall safety profile of new magnetic resonance (MR) and ultrasound agents. In regard to preclinical investigations, most of the work performed in the last 2 years has been with MR and ultrasound. In MR, research efforts continue to be focused on the development of targeted agents. In ultrasound, research efforts are split between studies looking at new imaging methods and early studies of targeted agents. In regard to the clinical application of contrast media, the published literature continues to be dominated by MR. Investigations include the study of disease in clinical trials and in animal models. A large number of studies continue to be published in regard to new techniques and applications within the field of contrast-enhanced magnetic resonance angiography. This field represents the single, largest new clinical application of contrast media in MR to emerge in the last decade. New clinical research continues to be published regarding the use of contrast media in computed tomography (CT), ultrasound, and x-ray angiography. The introduction of spiral CT (together with the multidetector scanners) has led to greater utilization of this modality, as well as intravenous iodinated contrast media. The number of publications regarding clinical applications of intravenously injected ultrasound contrast agents remains low, with the high expectations in regard to growth (in terms of number of exams using contrast) of the last decade yet to be fulfilled.

New developments in the sonographic assessment of ovarian, uterine, and breast vascularity

Recent developments in ultrasound have presented new opportunities for assessing tissue vascularity and blood flow with ultrasound. These new methods include 3D imaging, power Doppler sonography, a variety of harmonic imaging techniques, ultrasound contrast agents, electronic compounding, and pulse sequencing methods that improve the signal-to-noise relationship as well as structural conspicuity. By using these technological advances, it is now possible to assess macroscopic blood flow in organs and tumors, and to assess changes in flow and vascularity that occur in response to therapeutic efforts. This review article describes and illustrates the concepts and methods used to evaluate vascularity and blood flow in tissues with ultrasound. It describes some of the potential clinical applications of these new techniques in the ovary, uterus, endometrium, adnexal vessels, and breast.

Nonpalpable breast lesions: evaluation with power Doppler US and a microbubble contrast agent-initial experience

PURPOSE

To evaluate power Doppler ultrasonography (US) performed with a microbubble US contrast agent in the differentiation of nonpalpable breast lesions.

MATERIALS AND METHODS

Fifty nonpalpable breast lesions in 50 patients were prospectively evaluated with power Doppler US before and after injection of the contrast agent SH U 508A. Lesion vascularity and the morphology of vessels on US scans were analyzed and were correlated with histologic results.

RESULTS

Surgical excision revealed 22 cancers and 28 benign lesions. At nonenhanced power Doppler US, eight (36%) of 22 cancers and four (14%) of 28 benign lesions were vascular. At contrast agent-enhanced power Doppler US, 21 (95%) cancers and six (21%) benign lesions were vascular (P <.001). Irregular vessels were seen in three cancers and one benign lesion at nonenhanced power Doppler US and in 11 cancers and one benign lesion at contrast-enhanced power Doppler US. By using the presence of vascularity in the mass as the diagnostic criterion for malignancy, the sensitivity, specificity, and positive and negative predictive values of power Doppler US changed from 36%, 86%, 67%, and 63%, respectively, to 95%, 79%, 78%, and 96% after contrast agent injection.

CONCLUSION

Contrast-enhanced power Doppler US was superior to nonenhanced power Doppler US in the demonstration and characterization of tumor vascularity in nonpalpable breast lesions. Contrast-enhanced power Doppler US may be useful for the differentiation between nonpalpable breast cancers and benign tumors.

Assessment of the vascularization of neuroendocrine tumors by stimulated acoustic emission of SH U 508A ultrasound contrast agent and color or power Doppler sonography

RATIONALE AND OBJECTIVES

To assess the vascularization of neuroendocrine tumors by stimulated acoustic emission (SAE) of SH U 508A during the blood pool phase in comparison with contrast-enhanced Doppler sonography.

METHODS

Thirty-six patients with neuroendocrine tumors received contrast-enhanced Doppler sonography and 21, an additional SAE. To classify tumor perfusion on Doppler sonography, a 4-step rating score was introduced: (1) no vessels (hypoperfusion); (2) one feeding or central vessel (hypoperfusion); (3) some vessels (hyperperfusion); and (4) disseminated vessels (hyperperfusion). In 36 patients, 1 pancreatic primary tumor, 33 liver metastases, 1 splenic metastasis, and 1 lymph node metastasis were examined. Results were correlated with biphasic spiral CT (n = 35) and angiography (n = 2).

RESULTS

Arterial-phase CT and digital subtraction angiography revealed 18 hyper- and 18 hypoperfused lesions. Contrast-enhanced Doppler correctly classified 15 of 18 patients (83%) with hyperperfused lesions as well as 16 of 18 (89%) hypoperfused tumors by applying the rating score. SAE correctly identified 4 of 9 hyperperfused lesions (44%), 2 were isoperfused compared with normal liver tissue (22%), and 3 were hypoperfused (33%). Of 12 hypoperfused lesions, 11 were classified correctly (92%), and 1 showed isoperfusion. Hence, the positive and negative predictive values for SAE were 80% and 69%, respectively. For contrast-enhanced Doppler sonography, positive and negative predictive values were 88% and 84%, respectively.

CONCLUSIONS

Blood pool SAE failed to determine subtle tumor perfusion correctly. The rating score for contrast-enhanced Doppler sonography characterized tumor perfusion with high accuracy. The use of a contrast agent significantly improved perfusion characterization.

Contrast media research

This selective review highlights research in contrast media development and application in the field of diagnostic radiology in 1998 and 1999. The focus is on research published in Investigative Radiology, supplemented with work from other publications in the few areas not extensively covered by the journal. Studies continue to be performed, although at a low level, examining safety issues. Most preclinical investigations have focused on MR and ultrasound agents. In MR, the research effort is concentrated on the development of targeted agents; in ultrasound, work is focused on the characterization of basic contrast mechanisms. The demonstration of clinical applications is still dominated by work with MR, both in disease models and human investigations. The use of extracellular gadolinium chelates to enhance visualization of blood vessels (the field of contrast-enhanced MR angiography) is the largest single new clinical application of contrast media to emerge in several years. New clinical applications continue to be pursued with contrast media in CT, ultrasound, and x-ray angiography. As intravenously injected ultrasound contrast agents come to market, trials demonstrating clinical applications and subsequent scientific publications will increase in number.