Gastrointestinal stromal tumors treated with imatinib: monitoring response with contrast-enhanced sonography

State-of-the-art mass spectrometry imaging applications in biomedical research

Mass spectrometry imaging has advanced from a niche technique to a widely applied spatial biology tool operating at the forefront of numerous fields, most notably making a significant impact in biomedical pharmacological research. The growth of the field has gone hand in hand with an increase in publications and usage of the technique by new laboratories, and consequently this has led to a shift from general MSI reviews to topic-specific reviews. Given this development, we see the need to recapitulate the strengths of MSI by providing a more holistic overview of state-of-the-art MSI studies to provide the new generation of researchers with an up-to-date reference framework. Here we review scientific advances for the six largest biomedical fields of MSI application (oncology, pharmacology, neurology, cardiovascular diseases, endocrinology, and rheumatology). These publications thereby give examples for at least one of the following categories: they provide novel mechanistic insights, use an exceptionally large cohort size, establish a workflow that has the potential to become a high-impact methodology, or are highly cited in their field. We finally have a look into new emerging fields and trends in MSI (immunology, microbiology, infectious diseases, and aging), as applied MSI is continuously broadening as a result of technological breakthroughs.

Quantitative evaluation of colorectal tumour vasculature using contrast-enhanced ultrasound: Correlation with angiogenesis and prognostic significance

BACKGROUND

Ultrasound is a vital tool for the diagnosis and management of colorectal cancer (CRC). Contrast-enhanced ultrasound (CEUS) is a non-invasive, safe, and cost-effective method for evaluating tumour blood vessels, that play a crucial role in tumour growth and progression.

AIM

To explore CEUS's role in the quantitative evaluation of CRC blood vessels and their correlation with angiogenesis markers and prognosis.

METHODS

This study prospectively enrolled 100 patients with CRC confirmed by histopathology. All patients received preoperative CEUS examinations. Quantitative parameters, such as peak intensity (PI), time to peak (TTP), and area under the curve (AUC), were derived from time-intensity curve (TIC) analysis. Tumour tissue samples were obtained during surgery and examined immunohistochemically to assess the expression of angiogenesis markers, including vascular endothelial growth factor (VEGF) and microvessel density (MVD). The correlation between CEUS parameters, angiogenesis markers, and clinicopathological features was evaluated using appropriate statistical tests.

RESULTS

Quantitative CEUS parameters (PI, TTP, and AUC) showed significant correlations with VEGF expression (P < 0.001) and MVD (P < 0.001), indicating a strong link between tumour blood vessels and angiogenesis. Increased PI, reduced TTP, and expanded AUC values were significantly related to higher tumour stage (P < 0.001), lymph node metastasis (P < 0.001), and distant metastasis (P < 0.001). Furthermore, these parameters were recognized as independent predictors of overall survival and disease-free survival in multivariate analysis (P < 0.001).

CONCLUSION

CEUS has a high potential in guiding treatment planning and predicting patient outcomes. However, more comprehensive, multicentre studies are required to validate the clinical utility of CEUS in CRC management.

New calibration setup for quantitative DCE-US imaging protocol: Toward standardization

BACKGROUND

The DCE-US (Dynamic Contrast-Enhanced Ultrasonography) imaging protocol predicts the vascular modifications compared with Response Evaluation Criteria in Solid Tumors (RECIST) based mainly on morphological changes. A quantitative biomarker has been validated through the DCE-US multi-centric study for early monitoring of the efficiency of anti-angiogenic cancer treatments. In this context, the question of transposing the use of this biomarker to other types of ultrasound scanners, probes and settings has arisen to maintain the follow-up of patients under anti-angiogenic treatments. As a consequence, radiologists encounter standardization issues between the different generations of ultrasound scanners to perform quantitative imaging protocols.

PURPOSE

The aim of this study was to develop a new calibration setup to transpose the DCE-US imaging protocol to the new generation of ultrasound scanners using both abdominal and linear probes.

METHODS

This calibration method has been designed to be easily reproducible and optimized, reducing the time required and cost incurred. It is based on an original set-up that includes using a concentration splitter to measure the variation of the harmonic signal intensity, obtained from the Area Under the time-intensity Curve (AUC) as a function of various contrast-agent concentrations. The splitter provided four different concentrations simultaneously ranging from 12.5% to 100% of the initial concentration of the SonoVue contrast agent (Bracco Imaging S.p.A., Milan, Italy), therefore, measuring four AUCs in a single injection. The plot of the AUC as a function of the four contrast agent concentrations represents the intensity variation of the harmonic signal: the slope being the calibration parameter. The standardization through this method implied that both generations of ultrasound scanners had to have the same slopes to be considered as calibrated. This method was tested on two ultrasound scanners from the same manufacturer (Aplio500, Aplioi900, Canon Medical Systems, Tokyo, Japan). The Aplio500 used the settings defined by the initial multicenter DCE-US study. The Mechanical Index (MI) and the Color Gain (CG) of the Aplioi900 have been adjusted to match those of the Aplio500. The reliability of the new setup was evaluated in terms of measurement repeatability, and reproducibility with the agreement between the measurements obtained once the two ultrasound scanners were calibrated.

RESULTS

The new setup provided excellent repeatability measurements with a value of 96.8%. Once the two ultrasound scanners have been calibrated for both types of probes, the reproducibility was excellent with the agreement between their respective quantitative measurement was at the lowest 95.4% and at the best 98.8%. The settings of the Aplioi900 (Canon Medical Systems) were adjusted to match those of the Aplio500 (Canon Medical Systems) and these validated settings were for the abdominal probe: MI = 0.13 and CG = 34 dB; and for the linear probe: MI = 0.10 and CG = 38 dB.

CONCLUSION

This new calibration setup provided reliable measurements and enabled the rapid transfer and the use of the DCE-US imaging protocol on new ultrasound scanners, thus permitting a continuation of the therapeutic evaluation of patients through quantitative imaging.

Outcomes of Patients with Gastrointestinal Stromal Tumors in the Past Decade

BACKGROUND

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal neoplasms of the gastrointestinal tract (GIT) that represent approximately 1 to 2 percent of primary gastrointestinal (GI) cancers. Owing to their rarity, very little is known about their overall epidemiology, and the prognostic factors of their pathology. The current study aimed to evaluate the independent determinants of mortality in patients diagnosed with GISTs over the past decade.

METHODS

Our study comprised 2374 patients diagnosed with GISTs from 2000 to 2017 from the Surveillance, Epidemiology, and End Results (SEER) database. We analyzed the baseline characteristics, and overall mortality (OM), as well as the cancer-specific mortality (CSM) of GISTs. Variables with a p value < 0.01 in the univariate Cox regression were incorporated into the multivariate Cox model, to determine the independent prognostic factors.

RESULTS

Multivariate Cox proportional hazard regression analyses of factors affecting the all-cause mortality and GIST-related mortality among US patients between 2010 and 2017 revealed a higher overall mortality in non-Hispanic Black patients (HR = 1.516, 95% CI 1.172-1.961, p = 0.002), patients aged 80+ (HR = 9.783, 95% CI 4.185-22.868, p = 0), followed by those aged 60-79 (HR = 3.408, 95% CI 1.488-7.807, p = 0.004); male patients (HR = 1.795, 95% CI 1.461-2.206, p < 0.001); patients with advanced disease with distant metastasis (HR = 3.865, 95% CI 2.977-5.019, p < 0.001), followed by cases with regional involvement via both direct extension and lymph node involvement (HR = 3.853, 95% CI 1.551-9.57, p = 0.004); and widowed patients (HR = 1.975, 95% CI 1.494-2.61, p < 0.001), followed by single patients (HR = 1.53, 95% CI 1.154-2.028, p = 0.003). The highest CSM was observed in the same groups, except widowed patients and patients aged 60-79. The highest CSM was also observed among patients that underwent chemotherapy (HR = 1.687, 95% CI 1.19-2.392, p = 0.003).

CONCLUSION

In this updated study on the outcomes of patients with GISTs, we found that non-Hispanic Black patients, male patients, and patients older than 60 years have a higher mortality with GISTs. Furthermore, patients who have received chemotherapy have a higher GIST-specific mortality, and married patients have a lower mortality. However, we do not know to what extent these independent prognostic factors interact with each other to influence mortality. This study paves the way for future studies addressing these interactions. The results of this study may help treating clinicians to identify patient populations associated with a dismal prognosis, as those may require closer follow-up and more intensive therapy; furthermore, with married patients having a better survival rate, we hope to encourage clinicians to involve family members of the affected patients early in the disease course, as the social support might impact the prognosis.

VEGFR2 targeted microbubble-based ultrasound molecular imaging improving the diagnostic sensitivity of microinvasive cervical cancer

BACKGROUND

The current diagnostic methods of microinvasive cervical cancer lesions are imaging diagnosis and pathological evaluation. Pathological evaluation is invasive and imaging approaches are of extremely low diagnostic performance. There is a paucity of effective and noninvasive imaging approaches for these extremely early cervical cancer during clinical practice. In recent years, ultrasound molecular imaging (USMI) with vascular endothelial growth factor receptor type 2 (VEGFR2) targeted microbubble (MB_VEGFR2) has been reported to improve the early diagnosis rates of breast cancer (including ductal carcinoma in situ), pancreatic cancer and hepatic micrometastases. Herein, we aimed to assess the feasibility of MB_VEGFR2-based USMI in extremely early cervical cancer detection to provide an accurate imaging modality for microinvasive cervical cancer (International Federation of Gynecology and Obstetrics (FIGO) Stage IA1 and IA2).

RESULTS

We found MB_VEGFR2-based USMI could successfully distinguish extremely early lesions in diameter < 3 mm from surrounding normal tissues (all P < 0.05), and the sensitivity gradually decreased along with increasing tumor diameter. Moreover, normalized intensity difference (NID) values showed a good linear correlation with microvessel density (MVD) (R² = 0.75). In addition, all tumors could not be identified from surrounding muscles in subtracted ultrasound images when mice were administered MB_Con.

CONCLUSIONS

Overall, MB_VEGFR2-based USMI has huge potential for clinical application for the early detection of microinvasive cervical cancer (FIGO Stage IA1 and IA2), providing the foothold for future studies on the imaging screening of this patient population.

Contrast-Enhanced Ultrasound for Monitoring Treatment Response in Different Stages of Hepatocellular Carcinoma

Simple Summary

The evaluation of tumor response to anti-cancer therapy is critical in oncology for the prompt determination of subsequent treatment and follow-up strategies. Historically, response criteria have been based on tumor size changes; however, since the development of locoregional and molecular-targeted therapies in HCC (which act by disrupting tumor vascularization rather than tumor cells), changes in tumor vascularity and enhancement patterns have been considered to be more reliable. Contrast-enhanced ultrasound (CEUS) and dynamic CEUS, which allow microvessel perfusion studies, are emerging as promising tools for early tumor response evaluation. This article provides a general review of the current literature regarding the usefulness of CEUS in monitoring HCC response to therapy, highlighting the role of the procedure at different stages of the disease.

Abstract

The capacity of contrast-enhanced ultrasound (CEUS) to detect microvessel perfusion has received much attention in cancer imaging since it can be used to evaluate the enhancement patterns of the lesions during all vascular phases in real time, with higher temporal resolution as compared other imaging modalities. A rich body of literature has demonstrated the potential usefulness of CEUS in the assessment of HCC in response to both locoregional and systemic therapies. It is useful to evaluate the efficacy of ablation immediately after treatment to provide guidance for the retreatment of residual unablated tumors. In patients treated with transarterial chemoembolization (TACE), CEUS showed a high degree of concordance with computed tomography and magnetic resonance for the differentiation of responders from non-responders. Dynamic CEUS (D-CEUS) has emerged as a promising tool for the depicting changes in tumor perfusion during anti-angiogenetic treatment that can be associated with tumor response and clinical outcome. This article provides a general review of the current literature regarding the usefulness of CEUS in monitoring HCC response to therapy, highlighting the role of the procedure in different stages of the disease.

Contrast-enhanced ultrasonography in dogs with inflammatory bowel disease

Background

Contrast‐enhanced ultrasonography (CEUS) is used to evaluate vascularity of the gastrointestinal wall in neoplastic and inflammatory diseases.

Objective

To assess the feasibility of CEUS for the evaluation of duodenal perfusion in dogs with inflammatory bowel disease (IBD).

Animals

Forty‐two dogs with IBD and 20 clinically healthy dogs.

Methods

All CEUS studies of the duodenum were analyzed to obtain time‐intensity curves and perfusion parameters. The procedure was repeated in 12 IBD dogs 2 months after a standardized treatment.

Results

On CEUS, the duodenal wall showed a typical perfusion pattern characterized by a radial and simultaneous enhancement of the wall in all dogs. On qualitative assessment, no differences were observed in contrast medium distribution between healthy and affected dogs, or between dogs with IBD before and after treatment. Peak intensity (PI) and area under the curve (AUC) significantly differed between healthy (PI = 3.58 arbitrary units [au; 1.86‐4.93 au] and AUC = 47.63 au seconds [aus, 22.68‐62.15]) and affected dogs (PI = 5.10 au [0.63‐15.16 au] and AUC = 63.62 aus [5.31‐212.20 aus]; P = .03 and .03, respectively). No significant differences were found for the perfusion parameters before and after treatment.

Conclusions and Clinical Importance

We showed that CEUS allows discrimination between IBD affected dogs and healthy dogs by evaluation of time‐intensity curves, but did not provide useful information for monitoring therapeutic response. The qualitative assessment identified no significant differences between healthy and affected dogs, or between dogs before and after treatment.

Guidelines and Good Clinical Practice Recommendations for Contrast Enhanced Ultrasound (CEUS) in the Liver - Update 2020 - WFUMB in Cooperation with EFSUMB, AFSUMB, AIUM, and FLAUS

The present, updated document describes the fourth iteration of recommendations for the hepatic use of contrast enhanced ultrasound (CEUS), first initiated in 2004 by the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB). The previous updated editions of the guidelines reflected changes in the available contrast agents and updated the guidelines not only for hepatic but also for non-hepatic applications.The 2012 guideline requires updating as previously the differences of the contrast agents were not precisely described and the differences in contrast phases as well as handling were not clearly indicated. In addition, more evidence has been published for all contrast agents. The update also reflects the most recent developments in contrast agents, including the United States Food and Drug Administration (FDA) approval as well as the extensive Asian experience, to produce a truly international perspective.These guidelines and recommendations provide general advice on the use of ultrasound contrast agents (UCA) and are intended to create standard protocols for the use and administration of UCA in liver applications on an international basis to improve the management of patients.

Guidelines and Good Clinical Practice Recommendations for Contrast-Enhanced Ultrasound (CEUS) in the Liver-Update 2020 WFUMB in Cooperation with EFSUMB, AFSUMB, AIUM, and FLAUS

The present, updated document describes the fourth iteration of recommendations for the hepatic use of contrast-enhanced ultrasound, first initiated in 2004 by the European Federation of Societies for Ultrasound in Medicine and Biology. The previous updated editions of the guidelines reflected changes in the available contrast agents and updated the guidelines not only for hepatic but also for non-hepatic applications. The 2012 guideline requires updating as, previously, the differences in the contrast agents were not precisely described and the differences in contrast phases as well as handling were not clearly indicated. In addition, more evidence has been published for all contrast agents. The update also reflects the most recent developments in contrast agents, including U.S. Food and Drug Administration approval and the extensive Asian experience, to produce a truly international perspective. These guidelines and recommendations provide general advice on the use of ultrasound contrast agents (UCAs) and are intended to create standard protocols for the use and administration of UCAs in liver applications on an international basis to improve the management of patients.

Single-center study: dynamic contrast-enhanced ultrasound in the diagnostic assessment of carotid body tumors

Background

Carotid body tumors (CBTs) depict the most common paraganglioma of the head and neck that can metastasize in up to 15% of cases. They develop either sporadically or hereditarily and may produce catecholamines ("functioning CBTs") resulting in associated symptoms like headache, palpitations or flush. Non-functioning CBTs usually present as slowly and often tender growing mass which may affect adjacent cranial nerves. CBTs can be visualized by ultrasound, CT, MRI or angiography. Pre-surgical interventional embolization, surgical resection and radiation therapy are therapeutical options. The aim of this retrospective single-center study is to assess the safe and real-time evaluation of CBTs by contrast-enhanced ultrasound (CEUS).

Methods

Ten patients with CBT were included in this study on whom CEUS was performed between 2007-2018 (mean age: 62 years). In 6/10 patients, results were confirmed by MRI, 4/12 patients underwent subsequent angiography. CEUS was performed and interpreted by a single consultant radiologist with experience since 2000 (EFSUMB level 3). VueBox^® software was used for standardized perfusion quantification.

Results

CEUS allowed to detect all CBTs and visualize intratumoral microcirculation. Perfusion quantification was performed in 6/10 cases. CBTs showed significantly reduced peak-enhancement (PE), reduced wash-in perfusion index (WiPI) and significantly elevated time to peak (TTP) compared to common carotid arteries (CCA).

Conclusions

CEUS is a useful and safe tool for identifying CBTs and evaluating intratumoral microperfusion at high spatial and temporal resolutions in real-time. In addition to conventional ultrasound, CT, MRI and digital substraction angiography (DSA), CEUS may be implemented in the future diagnostic work-up and follow-up of CBT patients.

Perfusion Quantification of Liver Metastases of Colorectal Cancer Treated with Anti-angiogenic-Based Therapy: Assessment of Intra- and Inter-observer Reproducibility of Parameters in Three Regions of Interest Outlining Lesions

This study evaluated the reproducibility of dynamic contrast-enhanced ultrasound (DCEUS) parameters outlining liver metastases of colorectal cancer in 45 patients, before and after anti-angiogenic-based therapy. Tumor enhancement was quantified by drawing three regions of interest (ROIs): (i) outlining the tumor based on portal phase DCEUS images, (ii) in the hypo-enhanced center of the lesion and (iii) outlining the lesion using parametric imaging. Perfusion parameters were extracted from time-intensity curves. Another ROI was drawn in healthy liver parenchyma for normalization. Intra- and inter-observer reproducibility of these parameters was evaluated using intra-class correlation coefficients (ICCs). For the three ROIs, both intra- and inter-observer reproducibility were excellent (ICCs ≥0.9) for 50.8% absolute parameters and were moderate to good (0.7 ≤ ICC < 0.9) for 26.7% of them. In healthy liver parenchyma and for normalized parameters, reproducibility was moderate to excellent for 59.4% of intensity parameters and was low (ICC <0.7) for almost all temporal parameters. This study indicates that DCEUS is a reproducible tool for evaluating perfusion parameters.

Quantitative Mass Spectrometry Imaging Reveals Mutation Status-independent Lack of Imatinib in Liver Metastases of Gastrointestinal Stromal Tumors

Mass spectrometry imaging (MSI) is an enabling technology for label-free drug disposition studies at high spatial resolution in life science- and pharmaceutical research. We present the first extensive clinical matrix-assisted laser desorption/ionization (MALDI) quantitative mass spectrometry imaging (qMSI) study of drug uptake and distribution in clinical specimen, analyzing 56 specimens of tumor and corresponding non-tumor tissues from 27 imatinib-treated patients with the biopsy-proven rare disease gastrointestinal stromal tumors (GIST). For validation, we compared MALDI-TOF-qMSI with conventional UPLC-ESI-QTOF-MS-based quantification from tissue extracts and with ultra-high resolution MALDI-FTICR-qMSI. We introduced a novel generalized nonlinear calibration model of drug quantities based on computational evaluation of drug-containing areas that enabled better data fitting and assessment of the inherent method nonlinearities. Imatinib tissue spatial maps revealed striking inefficiency in drug penetration into GIST liver metastases even though the corresponding healthy liver tissues in the vicinity showed abundant imatinib levels beyond the limit of quantification (LOQ), thus providing evidence for secondary drug resistance independent of mutation status. Taken together, these findings underscore the important application of MALDI-qMSI in studying the spatial distribution of molecularly targeted therapeutics in oncology, namely to serve as orthogonal post-surgical approach to evaluate the contribution of anticancer drug disposition to resistance against treatment.

Imaging pediatric gastrointestinal stromal tumor (GIST)

BACKGROUND

Gastrointestinal stromal tumors (GIST) are extremely rare in children. Imaging plays a key role in staging and monitoring therapy (surgical and with tyrosine kinase inhibitors). The vast majority of articles addressing imaging of GIST base on adults and are based on CT. The subtype "pediatric GIST" - if at all - is only mentioned in a dependent clause. Although the imaging features in children and adults are similar, histology, clinical course and thus imaging approach are different.

METHODS

A PubMed search using the search terms "Gastrointestinal stromal tumor, GIST, WT GIST, children, pediatric, carney's triad, imaging, staging, follow-up, MRI, CEUS, ultrasonography, Positron emission tomography" was conducted. Studies that reported on laparoscopy, endoscopy and surgical techniques only were excluded.

RESULTS

Based on our selective literature review, we present alternative radiological imaging strategies using MRI, contrast enhanced ultrasound (CEUS) and PET-CT to stage and follow-up pediatric GIST patients. As pediatric GIST often is a chronic disease, minimizing exposure to ionizing radiation is mandatory.

CONCLUSION

MRI, contrast enhanced ultrasound and PET-CT instead of CT are the imaging modalities to evaluate pediatric GIST.

TYPE OF STUDY

Systematic review LEVEL OF EVIDENCE: III.

Dynamic Three-Dimensional Contrast-Enhanced Ultrasound to Predict Therapeutic Response of Radiofrequency Ablation in Hepatocellular Carcinoma: Preliminary Findings

BACKGROUND & AIMS

To investigate the value of dynamic three-dimensional contrast-enhanced ultrasound (3D-CEUS) in the assessment of therapeutic response of hepatocellular carcinoma (HCC) treated with radiofrequency ablation (RFA).

METHODS

Forty-two patients (31 men and 11 women; mean age (52.1 ± 13.1 years)) with 42 clinical diagnosed HCC lesions (size range 14-48 mm; mean size 28.4 ± 9.9 mm) treated by RFA were included. All patients underwent two-dimensional contrast-enhanced ultrasound (2D-CEUS) and 3D-CEUS 1 month after treatment. Two radiologists assessed the absence (complete response, CR) or presence (residual tumor, RT) of any arterially hyperenhancing nodules within or along the margin of the treated HCC lesions. Complete response on magnetic resonance (MR) imaging acted as standard of reference (SOR).

RESULTS

After RFA treatment, 3D-CEUS was successfully conducted in 34 HCC lesions. CR was observed on both 2D-CEUS and 3D-CEUS in 25/42 (59.5%) HCC and RT in 6/42 (14.3%) HCC lesions. In 3/42 (7.1%) HCC lesion, RT was documented by SOR and 3D-CEUS, but it was not appreciable at 2D-CEUS. In 3/42 (7.1%) HCC lesion, the presence of peripheral RT was suspected by both 2D-CEUS and 3D-CEUS, but it was not confirmed by SOR. No statistically significant difference between 2D-CEUS and 3D-CEUS in depicting either CR or RT was found (P = 0.25). Combined with dynamic 3D-CEUS, the diagnostic accuracy was improved from 85.7% to 92.9%.

CONCLUSIONS

3D-CEUS might be helpful in better diagnostic performance in the assessment of therapeutic response of HCC treated after RFA.

Comparison of Contrast-Enhanced Ultrasound and Positron Emission Tomography/Computed Tomography (PET/CT) in Lymphoma

Background

This study aimed to assess the value of contrast-enhanced ultrasound (CEUS) in the diagnosis and prognosis of lymphoma based on PET-CT.

Material/Methods

Our study included 88 superficial lymph nodes and 63 patients who underwent ultrasound-guided biopsy or surgery for pathology from October 2015 to March 2017. All lymph nodes were assessed by CEUS and PET-CT. CEUS and PET-CT parameters were recorded, including arrive time (AT), time to peak (TTP), base intensity (BI), peak intensity (PI), ascending slope (AS), descending slope (DS), area under the TIC curve (AUC), maximum standardized uptake value (SUVmax), and mean standardized uptake value (SUVmean). Pearson’s correlation was used to assess the associations of CEUS and PET-CT parameters.

Results

Of the 88 lymph nodes examined,12 were Hodgkin’s lymphoma (HL) and76 were non-Hodgkin’s lymphoma (NHL). The variations of CEUS dose parameters (ΔI, AUC, and AS) were positively correlated with PET-CT results (SUVmax and TLG). Correlation coefficients were 0.609, 0.518, 0.456, 0.630, 0.593, and 0. 532, respectively. The remaining time values (AT, TP, and ΔT) were negatively associated with PET-CT results. Correlation coefficients were −0.239, −0.272, −0.284and −0.377, −0.391, and −0.320, respectively.

Conclusions

Quantitative CEUS data were correlated with PET-CT values, with potential use in the diagnosis of lymphoma.

Pediatric gastrointestinal stromal tumors-a review of diagnostic modalities

Gastrointestinal stromal tumors are exceedingly rare tumors in the pediatric population, as a result many clinicians either may never see this diagnosis or will encounter it only a few times throughout their careers. It is imperative in the pediatric population to follow appropriate steps to ensure a swift diagnosis and referral to specialized centers that are equipped with the multidisciplinary teams accustomed to treating rare diseases. This review aims to discuss the most recent data available on the diagnostic modalities utilized in cases of suspected Pediatric GIST.

Role of contrast-enhanced ultrasound in evaluation of the bowel

Contrast-enhanced ultrasound (CEUS) of the gastrointestinal tract provides vascular information helpful for characterizing masses and other pathologies in and around the bowel, similar to contrast applications in other solid organs. However, the use of microbubble contrast agents for the bowel provides additional unique contributions as it gives both subjective and objective information about mural and mesenteric blood flow, invaluable for the determination of disease activity in those many patients affected by inflammatory bowel disease (IBD). IBD is a lifelong chronic disease and has its peak age of onset in adolescence or young adult life. Today, we have moved away from treating patient’s symptoms and strive instead to alter the course of disease by obtaining mucosal healing. Expensive and aggressive biologic therapies and lack of agreement of patient’s symptoms with their disease activity and complications necessitate frequent imaging surveillance, which must be safe, readily available, inexpensive, and effective. Ultrasound with the benefit of contrast enhancement meets these requirements and is shown in meta-analysis to be equivalent to CT and MRI scans for these indications.

Dynamic Contrast-Enhanced Ultrasound of Colorectal Liver Metastases as an Imaging Modality for Early Response Prediction to Chemotherapy

Our aim was to investigate whether dynamic contrast-enhanced ultrasound (DCE-US) can detect early changes in perfusion of colorectal liver metastases after initiation of chemotherapy. Newly diagnosed patients with colorectal cancer with liver metastases were enrolled in this explorative prospective study. Patients were treated with capecitabine or 5-fluorouracil-based chemotherapy with or without bevacizumab. DCE-US was performed before therapy (baseline) and again 10 days after initiation of treatment. Change in contrast-enhancement in one liver metastasis (indicator lesion) was measured. Treatment response was evaluated with a computed tomography (CT) scan after three cycles of treatment and the initially observed DCE-US change of the indicator lesion was related to the observed CT response. Eighteen patients were included. Six did not complete three series of chemotherapy and the evaluation CT scan, leaving twelve patients for analysis. Early changes in perfusion parameters using DCE-US did not correlate well with subsequent CT changes. A subgroup analysis of eight patients receiving bevacizumab, however, demonstrated a statistically significant correlation (p = 0.045) between early changes in perfusion measures of peak enhancement at DCE-US and tumor shrinkage at CT scan. The study indicates that early changes in DCE-US perfusion measures may predict subsequent treatment response of colorectal liver metastases in patients receiving bevacizumab.

Characteristics and Echogenicity of Clinical Ultrasound Contrast Agents: An In Vitro and In Vivo Comparison Study

OBJECTIVES

To compare physicochemical characteristics and in vitro and in vivo contrast-enhanced ultrasound imaging performance of 3 commercially available ultrasound contrast agents: SonoVue (Bracco Imaging SpA, Colleretto Giacosa, Italy; also marketed as Lumason in the USA), Definity (Lantheus Medical Imaging, North Billerica, MA) and Optison (GE Healthcare AS, Oslo, Norway).

METHODS

Physicochemical characteristics were measured with a Multisizer Coulter Counter (Beckman Coulter, Fullerton, CA). Two ultrasound systems (Aplio 500; Toshiba Medical Systems Corp, Tochigi-ken, Japan; and Logiq E9; GE Healthcare, Little Chalfont, England) were used with different transducers. Contrast enhancement was measured in vitro by dose-ranging measurements using a custom-built beaker setup; in vivo imaging performances were compared in pigs (heart and liver) and rabbits (liver). Quantitative analyses were performed with VueBox quantification software (Bracco Suisse SA, Plan-les-Ouates, Switzerland).

RESULTS

Measured physicochemical characteristics were in agreement with those provided by the manufacturers. In vitro data demonstrated that the performance of SonoVue was similar to or better than that of Definity but superior to Optison (normalized scattered power 2- to 10-fold higher with SonoVue). Similar results were obtained in vivo, although the duration of enhancement in the pig heart was longer for SonoVue compared to Definity, and quantitative analysis revealed higher enhancement for SonoVue (1.5-fold increase). For liver imaging, SonoVue and Definity showed similar contrast enhancement and duration of enhancement, but compared to Optison, both peak enhancement and duration of enhancement were superior for SonoVue (up to 2-fold increase).

CONCLUSIONS

Imaging performance of SonoVue was similar to or slightly better than that of Definity, but it was superior to Optison for the conditions used in this study.

Contrast-Enhanced Ultrasound with VEGFR2-Targeted Microbubbles for Monitoring Regorafenib Therapy Effects in Experimental Colorectal Adenocarcinomas in Rats with DCE-MRI and Immunohistochemical Validation

OBJECTIVES

To investigate contrast-enhanced ultrasound (CEUS) with VEGFR2-targeted microbubbles for monitoring therapy effects of regorafenib on experimental colon carcinomas in rats with correlation to dynamic contrast-enhanced MRI (DCE-MRI) and immunohistochemistry.

MATERIALS AND METHODS

Human colorectal adenocarcinoma xenografts (HT-29) were implanted subcutaneously in n = 21 (n = 11 therapy group; n = 10 control group) female athymic nude rats (Hsd: RH-Foxn1rnu). Animals were imaged at baseline and after a one-week daily treatment with regorafenib or a placebo (10 mg/kg bodyweight), using CEUS with VEGFR2-targeted microbubbles and DCE-MRI. In CEUS tumor perfusion was assessed during an early vascular phase (wash-in area under the curve = WiAUC) and VEGFR2-specific binding during a late molecular phase (signal intensity after 8 (SI8min) and 10 minutes (SI10min)), using a conventional 15L8 linear transducer (transmit frequency 7 MHz, dynamic range 80 dB, depth 25 mm). In DCE-MRI functional parameters plasma flow (PF) and plasma volume (PV) were quantified. For validation purposes, CEUS parameters were correlated with DCE-MRI parameters and immunohistochemical VEGFR2, CD31, Ki-67 and TUNEL stainings.

RESULTS

CEUS perfusion parameter WiAUC decreased significantly (116,989 ± 77,048 a.u. to 30,076 ± 27,095a.u.; p = 0.005) under therapy with no significant changes (133,932 ± 65,960 a.u. to 84,316 ± 74,144 a.u.; p = 0.093) in the control group. In the therapy group, the amount of bound microbubbles in the late phase was significantly lower in the therapy than in the control group on day 7 (SI8min: 283 ± 191 vs. 802 ± 460 a.u.; p = 0.006); SI10min: 226 ± 149 vs. 645 ± 461 a.u.; p = 0.009). PF and PV decreased significantly (PF: 147 ± 58 mL/100 mL/min to 71 ± 15 mL/100 mL/min; p = 0.003; PV: 13 ± 3% to 9 ± 4%; p = 0.040) in the therapy group. Immunohistochemistry revealed significantly fewer VEGFR2 (7.2 ± 1.8 vs. 17.8 ± 4.6; p < 0.001), CD31 (8.1 ± 3.0 vs. 20.8 ± 5.7; p < 0.001) and Ki-67 (318.7 ± 94.0 vs. 468.0 ± 133.8; p = 0.004) and significantly more TUNEL (672.7 ± 194.0 vs. 357.6 ± 192.0; p = 0.003) positive cells in the therapy group. CEUS parameters showed significant (p < 0.05) correlations to DCE-MRI parameters and immunohistochemistry.

CONCLUSIONS

CEUS with VEGFR2-targeted microbubbles allowed for monitoring regorafenib functional and molecular therapy effects on experimental colorectal adenocarcinomas with a significant decline of CEUS and DCE-MRI perfusion parameters as well as a significant reduction of specifically bound microbubbles under therapy, consistent with a reduced expression of VEGFR2.

Ultrasound contrast agents

Endoscopic ultrasound (EUS) plays an important role in imaging of the mediastinum and abdominal organs. Since the introduction of US contrast agents (UCA) for transabdominal US, attempts have been made to apply contrast-enhanced US techniques also to EUS. Since 2003, specific contrast-enhanced imaging was possible using EUS. Important studies have been published regarding contrast-enhanced EUS and the characterization of focal pancreatic lesions, lymph nodes, and subepithelial tumors. In this manuscript, we describe the relevant UCA, their application, and specific image acquisition as well as the principles of image tissue characterization using contrast-enhanced EUS. Safety issues, potential future developments, and EUS-specific issues are reviewed.

Three-dimensional Contrast-enhanced Ultrasound in Response Assessment for Breast Cancer: A Comparison with Dynamic Contrast-enhanced Magnetic Resonance Imaging and Pathology

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.

Mathematical Models of Contrast Transport Kinetics for Cancer Diagnostic Imaging: A Review

Angiogenesis plays a fundamental role in cancer growth and the formation of metastasis. Novel cancer therapies aimed at inhibiting angiogenic processes and/or disrupting angiogenic tumor vasculature are currently being developed and clinically tested. The need for earlier and improved cancer diagnosis, and for early evaluation and monitoring of therapeutic response to angiogenic treatment, have led to the development of several imaging methods for in vivo noninvasive assessment of angiogenesis. The combination of dynamic contrast-enhanced imaging with mathematical modeling of the contrast agent kinetics enables quantitative assessment of the structural and functional changes in the microvasculature that are associated with tumor angiogenesis. In this paper, we review quantitative imaging of angiogenesis with dynamic contrast-enhanced magnetic resonance imaging, computed tomography, and ultrasound.

Indications for surgery in advanced/metastatic GIST

Gastrointestinal stromal tumours (GISTs) are a relatively rare entity and often present as a locally advanced tumour or with metastatic disease. Complete surgical resection is the only means of cure in localised disease; however, imatinib therapy has greatly advanced the management of GIST and is established as both an adjunct to surgery in high-risk cases and as principle therapy in metastatic disease. Surgery in advanced GIST has undergone a renaissance in recent years with the potential for a combined treatment approach with either neoadjuvant imatinib in locally advanced primary disease or as an adjunct to imatinib in those with metastases or recurrent disease. Neoadjuvant imatinib can render a locally advanced primary GIST resectable, allow less invasive procedures or promote preservation of function, especially if the tumour is located in an anatomically difficult position. The role of surgery in metastatic or recurrent disease is more controversial and case selection is critical. The potential benefit is difficult to quantify, although surgery may have a limited favourable impact on progression-free survival and overall survival for those patients whose disease is responding to imatinib or those with limited focal progression. Patients with imatinib resistant disease should not be offered surgery unless as an emergency where palliative intervention may be justified.

Markers of Response to Antiangiogenic Therapies in Colorectal Cancer: Where Are We Now and What Should Be Next?

Despite advances in the treatment of colorectal cancer (CRC), it remains the second most common cause of cancer-related death in the Western world. Angiogenesis is a complex process that involves the formation of new blood vessels from preexisting vessels. It is essential for promoting cancer survival, growth, and dissemination. The inhibition of angiogenesis has been shown to prevent tumor progression experimentally, and several chemotherapeutic targets of tumor angiogenesis have been identified. These include anti-vascular endothelial growth factor (VEGF) treatments, such as bevacizumab (a VEGF-specific binding antibody) and anti-VEGF receptor tyrosine kinase inhibitors, although antiangiogenic therapy has been shown to be effective in the treatment of several cancers, including CRC. However, it is also associated with its own side effects and financial costs. Therefore, the identification of biomarkers that are able to identify patients who are more likely to benefit from antiangiogenic treatment is very important. This article intends to be a concise summary of the potential biomarkers that can predict or prognosticate the benefit of antiangiogenic treatments in CRC, and also what we can expect in the near future.

Use of Quantitative Dynamic Contrast-Enhanced Ultrasound to Assess Response to Antiangiogenic Therapy in Children and Adolescents With Solid Malignancies: A Pilot Study

OBJECTIVE

The purpose of this study was to investigate contrast-enhanced ultrasound assessment of tumor response to antiangiogenic therapy in children and adolescents with solid malignancies.

SUBJECTS AND METHODS

Children with recurrent solid tumors who were enrolled in an institutional phase 1 study of antiangiogenic therapy underwent contrast-enhanced ultrasound of target lesions before therapy, on therapy days 3 and 7, and at the end of course 1. Acoustic data from target lesion ROIs were used to measure peak enhancement, time to peak, rate of enhancement, total AUC, AUC during wash-in (AUC1), and AUC during washout (AUC2). The Cox regression model was used to assess the association between changes in parameters from baseline to follow-up time points and time to tumor progression. Values of p ≤ 0.050 were considered significant.

RESULTS

Target lesion sites included liver (n = 3), pleura (n = 2), and supraclavicular mass, soft-tissue component of bone metastasis, lung, retroperitoneum, peritoneum, lymph node, muscle mass, and perineum (n = 1 each). Hazard ratios for changes from baseline to end of course 1 for peak enhancement (1.17, p = 0.034), rate of enhancement (3.25, p = 0.029), and AUC1 (1.02, p = 0.040) were significantly associated with time to progression. Greater decreases in these parameters correlated with longer time to progression.

CONCLUSION

Contrast-enhanced ultrasound measurements of tumor peak enhancement, rate of enhancement, and AUC1 were early predictors of time to progression in a cohort of children and adolescents with recurrent solid tumors treated with antiangiogenic therapy. Further investigation of these findings in a larger population is warranted.

Evolution of contrast agents for ultrasound imaging and ultrasound-mediated drug delivery

Ultrasound (US) is one of the most frequently used diagnostic methods. It is a non-invasive, comparably inexpensive imaging method with a broad spectrum of applications, which can be increased even more by using bubbles as contrast agents (CAs). There are various different types of bubbles: filled with different gases, composed of soft- or hard-shell materials, and ranging in size from nano- to micrometers. These intravascular CAs enable functional analyses, e.g., to acquire organ perfusion in real-time. Molecular analyses are achieved by coupling specific ligands to the bubbles' shell, which bind to marker molecules in the area of interest. Bubbles can also be loaded with or attached to drugs, peptides or genes and can be destroyed by US pulses to locally release the entrapped agent. Recent studies show that US CAs are also valuable tools in hyperthermia-induced ablation therapy of tumors, or can increase cellular uptake of locally released drugs by enhancing membrane permeability. This review summarizes important steps in the development of US CAs and introduces the current clinical applications of contrast-enhanced US. Additionally, an overview of the recent developments in US probe design for functional and molecular diagnosis as well as for drug delivery is given.

Ultrasound imaging of breast tumor perfusion and neovascular morphology

A novel image processing strategy is detailed for simultaneous measurement of tumor perfusion and neovascular morphology parameters from a sequence of dynamic contrast-enhanced ultrasound (DCE-US) images. After normalization and tumor segmentation, a global time-intensity curve describing contrast agent flow was analyzed to derive surrogate measures of tumor perfusion (i.e., peak intensity, time-to-peak intensity, area under the curve, wash-in rate, wash-out rate). A maximum intensity image was generated from these same segmented image sequences, and each vascular component was skeletonized via a thinning algorithm. This skeletonized data set and collection of vessel segments were then investigated to extract parameters related to the neovascular network and physical architecture (i.e., vessel-to-tissue ratio, number of bifurcations, vessel count, average vessel length and tortuosity). An efficient computation of local perfusion parameters was also introduced and operated by averaging time-intensity curve data over each individual neovascular segment. Each skeletonized neovascular segment was then color-coded by these local measures to produce a parametric map detailing spatial properties of tumor perfusion. Longitudinal DCE-US image data sets were collected in six patients diagnosed with invasive breast cancer using a Philips iU22 ultrasound system equipped with a L9-3 transducer and Definity contrast agent. Patients were imaged using US before and after contrast agent dosing at baseline and again at weeks 6, 12, 18 and 24 after treatment started. Preliminary clinical results suggested that breast tumor response to neoadjuvant chemotherapy may be associated with temporal and spatial changes in DCE-US-derived parametric measures of tumor perfusion. Moreover, changes in neovascular morphology parametric measures may also help identify any breast tumor response (or lack thereof) to systemic treatment. Breast cancer management from early detection to therapeutic monitoring is currently undergoing profound changes. Novel imaging techniques that are sensitive to the unique biological conditions of each individual tumor represent valuable tools in the pursuit of personalized medicine.

Imaging of Tumor Angiogenesis for Radiologists--Part 2: Clinical Utility

Angiogenesis is a key cancer hallmark involved in tumor growth and metastasis development. Angiogenesis and tumor microenvironment significantly influence the response of tumors to therapies. Imaging techniques have changed our understanding of the process of angiogenesis, the resulting vascular performance, and the tumor microenvironment. This article reviews the status and potential clinical value of the imaging modalities used to assess the status of tumor vasculature in vivo, before, during, and after treatment.

Dynamic contrast-enhanced ultrasound for quantification of tissue perfusion

Dynamic contrast-enhanced ultrasound (US) imaging, a technique that uses microbubble contrast agents with diagnostic US, has recently been technically summarized and reviewed by a European Federation of Societies for Ultrasound in Medicine and Biology position paper. However, the practical applications of this imaging technique were not included. This article reviews and discusses the published literature on the clinical use of dynamic contrast-enhanced US. This review finds that dynamic contrast-enhanced US imaging is the most sensitive cross-sectional real-time method for measuring the perfusion of parenchymatous organs noninvasively. It can measure parenchymal perfusion and therefore can differentiate between benign and malignant tumors. The most important routine clinical role of dynamic contrast-enhanced US is the prediction of tumor responses to chemotherapy within a very short time, shorter than using Response Evaluation Criteria in Solid Tumors criteria. Other applications found include quantifying the hepatic transit time, diabetic kidneys, transplant grafts, and Crohn disease. In addition, the problems involved in using dynamic contrast-enhanced US are discussed.

Comparison of photoacoustically derived hemoglobin and oxygenation measurements with contrast-enhanced ultrasound estimated vascularity and immunohistochemical staining in a breast cancer model

In this preliminary study, we compared two noninvasive techniques for imaging intratumoral physiological conditions to immunohistochemical staining in a murine breast cancer model. MDA-MB-231 tumors were implanted in the mammary pad of 11 nude rats. Ultrasound and photoacoustic (PA) scanning were performed using a Vevo 2100 scanner (Visualsonics, Toronto, Canada). Contrast-enhanced ultrasound (CEUS) was used to create maximum intensity projections as a measure of tumor vascularity. PAs were used to determine total hemoglobin signal (HbT), oxygenation levels in detected blood (SO2 Avg), and oxygenation levels over the entire tumor area (SO2 Tot). Tumors were then stained for vascular endothelial growth factor (VEGF), cyclooxygenase-2 (Cox-2), and the platelet endothelial cell adhesion molecule CD31. Correlations between findings were analyzed using Pearson's coefficient. Significant correlation was observed between CEUS-derived vascularity measurements and both PA indicators of blood volume (r = 0.49 for HbT, r = 0.50 for SO2 Tot). Cox-2 showed significant negative correlation with SO2 Avg (r = -0.49, p = 0.020) and SO2 Tot (r = -0.43, p = 0.047), while CD31 showed significant negative correlation with CEUS-derived vascularity (r = -0.47, p = 0.036). However, no significant correlation was observed between VEGF expression and any imaging modality (p > 0.08). Photoacoustically derived HbT and SO2 Tot may be a good indicator of tumor fractional vascularity. While CEUS correlates with CD31 expression, photoacoustically derived SO2 Avg appears to be a better predictor of Cox-2 expression.

Validation of dynamic contrast-enhanced ultrasound in predicting outcomes of antiangiogenic therapy for solid tumors: the French multicenter support for innovative and expensive techniques study

OBJECTIVES

Dynamic contrast-enhanced ultrasound (DCE-US) has been used in single-center studies to evaluate tumor response to antiangiogenic treatments: the change of area under the perfusion curve (AUC), a criterion linked to blood volume, was consistently correlated with the Response Evaluation Criteria in Solid Tumors response. The main objective here was to do a multicentric validation of the use of DCE-US to evaluate tumor response in different solid tumor types treated by several antiangiogenic agents. A secondary objective was to evaluate the costs of the procedure.

MATERIALS AND METHODS

This prospective study included patients from 2007 to 2010 in 19 centers (8 teaching hospitals and 11 comprehensive cancer centers). All patients treated with antiangiogenic therapy were eligible. Dynamic contrast-enhanced ultrasound examinations were performed at baseline as well as on days 7, 15, 30, and 60. For each examination, a perfusion curve was recorded during 3 minutes after injection of a contrast agent. Change from baseline at each time point was estimated for each of 7 fitted criteria. The main end point was freedom from progression (FFP). Criterion/time-point combinations with the strongest correlation with FFP were analyzed further to estimate an optimal cutoff point.

RESULTS

A total of 1968 DCE-US examinations in 539 patients were analyzed. The median follow-up was 1.65 years. Variations from baseline were significant at day 30 for several criteria, with AUC having the most significant association with FFP (P = 0.00002). Patients with a greater than 40% decrease in AUC at day 30 had better FFP (P = 0.005) and overall survival (P = 0.05). The mean cost of each DCE-US was 180&OV0556;, which corresponds to $250 using the current exchange rate.

CONCLUSIONS

Dynamic contrast-enhanced ultrasound is a new functional imaging technique that provides a validated criterion, namely, the change of AUC from baseline to day 30, which is predictive of tumor progression in a large multicenter cohort. Because of its low cost, it should be considered in the routine evaluation of solid tumors treated with antiangiogenic therapy.

Recent developments in dynamic contrast-enhanced ultrasound imaging of tumor angiogenesis

Angiogenesis is a critical process for tumor growth and metastatic dissemination. There is tremendous interest in the development of noninvasive methods for imaging tumor angiogenesis, and ultrasound (US) is an emerging platform technology to address this challenge. The introduction of intravascular microbubble contrast agents not only allows real-time visualization of tumor perfusion during an US examination, but they can be functionalized with specific ligands to permit molecular US imaging of angiogenic biomarkers that are overexpressed on the tumor endothelium. In this article, we will review current concepts and developing trends for US imaging of tumor angiogenesis, including relevant preclinical and clinicsal findings.

Early prediction of response to sorafenib in patients with advanced hepatocellular carcinoma: the role of dynamic contrast enhanced ultrasound

BACKGROUND & AIMS

Sorafenib has become the standard first-line treatment for patients with advanced HCC and acts by inducing alterations in tumor vascularity. We wanted to evaluate the feasibility of dynamic CEUS (D-CEUS) as a predictor of early tumor response to sorafenib and to correlate functional parameters with clinical efficacy end points.

METHODS

Twenty-eight HCC patients treated with sorafenib 400mg bid were prospectively enrolled. CEUS was performed at baseline (T0) and after 15 (T1) and 30 (T2) days of treatment. Tumor vasculature was assessed in a specific harmonic mode associated with a perfusion and quantification software (Q-Lab, Philips). Variations between T1/T2 and T0 were calculated for five D-CEUS functional parameters (peak intensity, PI; time to PI, TP; area under the curve, AUC; slope of wash in, Pw; mean transit time, MTT) and were compared for responders and non-responders. The correlation between D-CEUS parameters, overall survival (OS), and progression-free survival (PFS) was also assessed. A p value <0.05 was considered statistically significant.

RESULTS

The percentage variation at T1 significantly correlated with response in three D-CEUS parameters (AUC, PI and Pw; p=0.002, <0.001, and 0.003, respectively). A decrease of AUC (p=0.045) and an increased/unchanged value of TP (p=0.029) and MTT (p=0.010) were associated with longer survival. Three D-CEUS parameters (AUC, TP, Pw) were significantly associated with PFS.

CONCLUSIONS

D-CEUS provides a reliable and early measure of efficacy for anti-angiogenic therapies and could be an excellent tool for selecting patients who will benefit from treatment.

Role of dynamic contrast-enhanced sonography for characterization and monitoring of extramedullary myeloma: comparison with serologic data

OBJECTIVE

To measure blood perfusion in extramedullary myeloma by contrast-enhanced sonography, correlate it with specific hematologic parameters, and determine their utility for local and systemic response monitoring.

METHODS

Twenty-five consecutive patients (14 male and 11 female; median age, 68 years) with extramedullary myeloma were included. After intravenous administration of 2.4 mL of sulfur hexafluoride, extramedullary myeloma masses were examined for 60 seconds. All patients underwent contrast-enhanced sonography at baseline, and 15 were monitored additionally (3 weeks during therapy). Average peak perfusion, regional blood flow (RBF), and regional blood volume (RBV) were calculated. Baseline perfusion parameters were compared with short-term follow-up sonographic data and serologic biomarkers (M gradient). For validation of extramedullary myeloma and systemic myeloma, patients underwent midterm (<3 months) imaging and serologic diagnosis.

RESULTS

Patients with baseline β2-microglobulin (B2M) greater than 3.5 mg/L (n = 17) showed higher perfusion parameters compared with baseline B2M less than 3.5 mg/L (n = 8). At short-term follow-up, patients were classified by serologic criteria as responders (n = 9) and nonresponders (n = 6) and by sonographic criteria as responders (n = 10) and nonresponders (n = 5). In sonographic responders, mean peak, RBV, and RBF dropped from 59.13, 1446.09, and 71.52 (artificial units) at baseline to 29.30, 364.19, and 34.64 at follow-up (P < .05), whereas in nonresponders, perfusion parameters increased from 33.18, 789.82, and 36.92 at baseline to 51.14, 1491.06, and 65.34 at follow-up (P > .05). Prediction of a midterm course of systemic myeloma using serologic data yielded sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 0.66, 0.77, 0.66, and 0.77, whereas sonographic results (judged by RBV) yielded values of 0.66, 0.55, 0.5, and 0.71. Separate prediction of a local (extramedullary myeloma) response by sonography yielded sensitivity, specificity, PPV, and NPV of 0.8, 1.0, 1.0, and 0.71.

CONCLUSIONS

Contrast-enhanced sonography is a valuable tool for short-term monitoring of the treatment response in extramedullary myeloma.

The benefit of using CT-perfusion imaging for reliable response monitoring in patients with gastrointestinal stromal tumor (GIST) undergoing treatment with novel targeted agents

Solely size-based response criteria may be unreliable in patients with gastrointestinal stromal tumors (GIST) treated with tyrosine kinase inhibitors, because they typically underestimate responses to treatment. As GISTs are generally hypervascularized and novel targeted drugs knowingly affect angiogenic signaling pathways, perfusion measurements are expected to deliver important information about their efficacy. This pictorial essay illustrates the benefit of using complementary CT-perfusion-based measurements for more accurate evaluation of response to therapy in GIST.

Correlation of ultrasound contrast agent derived blood flow parameters with immunohistochemical angiogenesis markers in murine xenograft tumor models

PURPOSE

In this study we used temporal analysis of ultrasound contrast agent (UCA) estimate blood flow dynamics and demonstrate their improved correlation to angiogenesis markers relative to previously reported, non-temporal fractional vascularity estimates.

MATERIALS AND METHODS

Breast tumor (NMU) or glioma (C6) cells were implanted in either the abdomen or thigh of 144 rats. After 6, 8 or 10 days, rats received a bolus UCA injection of Optison (GE Healthcare, Princeton, NJ; 0.4 ml/kg) during power Doppler imaging (PDI), harmonic imaging (HI), and microflow imaging (MFI) using an Aplio ultrasound scanner with 7.5 MHz linear array (Toshiba America Medical Systems, Tustin, CA). Time-intensity curves of contrast wash-in were constructed on a pixel-by-pixel basis and averaged to calculate maximum intensity, time to peak, perfusion, and time integrated intensity (TII). Tumors were then stained for four immunohistochemical markers (bFGF, CD31, COX-2, and VEGF). Correlations between temporal parameters and the angiogenesis markers were investigated for each imaging mode. Effects of tumor model and implant location on these correlations were also investigated.

RESULTS

Significant correlation over the entire dataset was only observed between TII and VEGF for all three imaging modes (R=-0.35, -0.54, -0.32 for PDI, HI and MFI, respectively; p<0.0001). Tumor type and location affected these correlations, with the strongest correlation of TII to VEGF found to be with implanted C6 cells (R=-0.43, -0.54, -0.52 for PDI, HI and MFI, respectively; p<0.0002).

CONCLUSIONS

While UCA-derived temporal blood flow parameters were found to correlate strongly with VEGF expression, these correlations were also found to be influenced by both tumor type and implant location.

Standardization of dynamic contrast-enhanced ultrasound for the evaluation of antiangiogenic therapies: the French multicenter Support for Innovative and Expensive Techniques Study

OBJECTIVES

The objectives of this study are to describe the standardization and dissemination of dynamic contrast-enhanced ultrasound (DCE-US) for the evaluation of antiangiogenic treatments in solid tumors across 19 oncology centers in France and to define a quality score to account for the variability of the evaluation criteria used to collect DCE-US data.

MATERIALS AND METHODS

This prospective Soutien aux Techniques Innovantes Coûteuses (Support for Innovative and Expensive Techniques) DCE-US study included patients with metastatic breast cancer, melanoma, colon cancer, gastrointestinal stromal tumors, renal cell carcinoma and patients with primary hepatocellular carcinoma tumors treated with antiangiogenic therapy. The DCE-US method was made available across 19 oncology centers in France. Overall, 2339 DCE-US examinations were performed by 65 radiologists in 539 patients.One target site per patient was studied. Standardized DCE-US examinations were performed before treatment (day 0) and at days 7, 15, 30, and 60. Dynamic contrast-enhanced ultrasound data were transferred from the different sites to the main study center at the Institut Gustave-Roussy for analysis. Quantitative analyses were performed with a mathematical model to determine 7 DCE-US functional parameters using raw linear data. Radiologists had to evaluate 6 criteria that were potentially linked to the precision of the evaluation of these parameters: lesion size, target motion, loss of target, clear borders, total acquisition of wash-in, and vascular recognition imaging window adapted to the lesion size.Eighteen DCE-US examinations were randomly selected from the Soutien aux Techniques Innovantes Coûteuses (Support for Innovative and Expensive Techniques) database. Each examination was quantified twice by 8 engineers/radiologists trained to evaluate the perfusion parameters. The intraobserver variability was estimated on the basis of differences between examinations performed by the same radiologist. The mean coefficient of variability associated with each quality criterion was estimated. The final quality score, ranging from 0 to 5, was defined according to the value of coefficient of variability for each criterion.

RESULTS

A total of 2062 examinations were stored with raw linear data. Five criteria were found to have a major impact on quality: lesion size, motion, loss of target, borders, and total acquisition of wash-in. Only 3% of the examinations were of poor quality (quality of 0); quality was correlated with the radiologists' experience, such that it was significantly higher for radiologists who had performed more than 60 DCE-US examinations (P < 0.0001).

CONCLUSIONS

The DCE-US methodology has been successfully provided to several centers across France together with strict rules for quality assessment. Only 3% of examinations carried out at these centers were considered not interpretable.

Hepatocellular carcinoma treated with sorafenib: early detection of treatment response and major adverse events by contrast-enhanced US

BACKGROUND & AIMS

Early prediction of tumour response and major adverse events (AEs), especially liver failure, in patients with hepatocellular carcinoma (HCC) is essential for maximizing the clinical benefits of sorafenib. To evaluate the usefulness of dynamic contrast-enhanced ultrasound (DCE-US) for the early prediction of tumour response and major AEs in HCC patients.

METHODS

Thirty-seven HCC patients were started on a reduced dosage of sorafenib, subsequently increased to the standard dosage. Tumour response at 1 month was assessed by CT using the Response Evaluation Criteria in Solid Tumors (RECIST). Major AEs were defined as grade 3 or higher. DCE-US was performed before treatment (day 0) and on days 7, 14 and 28. Changes in perfusion parameters in the tumour and liver parenchyma between day 0 and later time points were compared between treatment responders and nonresponders based on RECIST and between patients who experienced major AEs and those who did not. Tumour results were also compared with progression-free survival (PFS) and overall survival (OS).

RESULTS

Tumour perfusion parameters based on the area under the time-intensity curve (AUC) were statistically significant, with AUC during washin on day 14, the most relevant for tumour response (P = 0.0016) and AUC during washin on day 7, the most relevant for both PFS (P = 0.009) and OS (P = 0.037). A decrease in total AUC between days 0 and 7 in the liver parenchyma was strongly correlated with major AEs (P = 0.0002).

CONCLUSION

DCE-US may be useful for the early prediction of tumour response and major AEs in patients with HCC.

Guidelines and good clinical practice recommendations for Contrast Enhanced Ultrasound (CEUS) in the liver - update 2012: A WFUMB-EFSUMB initiative in cooperation with representatives of AFSUMB, AIUM, ASUM, FLAUS and ICUS

Initially, a set of guidelines for the use of ultrasound contrast agents was published in 2004 dealing only with liver applications. A second edition of the guidelines in 2008 reflected changes in the available contrast agents and updated the guidelines for the liver, as well as implementing some non-liver applications. Time has moved on, and the need for international guidelines on the use of CEUS in the liver has become apparent. The present document describes the third iteration of recommendations for the hepatic use of contrast enhanced ultrasound (CEUS) using contrast specific imaging techniques. This joint WFUMB-EFSUMB initiative has implicated experts from major leading ultrasound societies worldwide. These liver CEUS guidelines are simultaneously published in the official journals of both organizing federations (i.e., Ultrasound in Medicine and Biology for WFUMB and Ultraschall in der Medizin/European Journal of Ultrasound for EFSUMB). These guidelines and recommendations provide general advice on the use of all currently clinically available ultrasound contrast agents (UCA). They are intended to create standard protocols for the use and administration of UCA in liver applications on an international basis and improve the management of patients worldwide.

A 32-month follow-up study of nanovesicle concentrations in blood from 12 patients with gastrointestinal stromal tumour treated with imatinib

Clinical studies have indicated that the NV (nanovesicle) concentration in blood samples is a potential indicator of clinical status and can be used to follow the development of the disease. For 32 months, we monitored the effect of imatinib treatment on NV concentrations in blood samples from 12 patients with GIST (gastrointestinal stromal tumour). The NV concentration before the treatment increased with respect to control by a factor of 3.5 on average (range 2.6–9.2). The first week after initiation of the treatment, the NV concentration increased considerably, by a factor of 13 on average (range 5.9–21.2), whereas on average, after 1 month, it decreased to the level of the control and remained at that level for at least 1.5 years. Recent assessment (after 2.5 years) showed a somewhat increased NV concentration, by a factor of 2 on average (range 0.7–3.9). Low NV concentrations in blood samples during the treatment reflect a favourable effect of imatinib in these patients and no remission of the disease was hitherto observed.

Phase II study of sorafenib in combination with cisplatin and 5-fluorouracil to treat recurrent or metastatic nasopharyngeal carcinoma

BACKGROUND

We aimed to investigate the efficacy and tolerability of sorafenib combined with cisplatin and 5-fluorouracil (5-FU) in patients with recurrent or metastatic nasopharyngeal carcinoma (NPC).

PATIENTS AND METHODS

It was a Simon two-stage designed trial. Chemotherapy-naive patients with recurrent or metastatic disease were enrolled. The regimen was sorafenib 400 mg orally b.i.d., cisplatin 80 mg/m(2) i.v. day 1, and 5-FU 1000 mg/m(2)/day CIV for 4 days, repeated every 21 days. After a maximum of six cycles of chemotherapy, patients received maintenance of sorafenib.

RESULTS

In total, 54 patients were enrolled. The objective response rate reached 77.8%, including 1 complete response and 41 partial responses. The median progression-free survival was 7.2 months (95% CI 6.8-8.4 months), and the median overall survival was 11.8 months (95% CI 10.6-18.7 months). Major toxic effects included hand-foot skin reaction, myelosuppression, and gastrointestinal (GI) reaction. The incidence of hemorrhage was 22.2%, and one patient with liver metastases died of GI bleeding. Contrast-enhanced ultrasonography was carried out in a subset of patients with liver metastases.

CONCLUSION

Combination of sorafenib, cisplatin (80 mg/m(2)) and 5-FU (3000 mg/m(2)) was tolerable and feasible in recurrent or metastatic NPC. Further randomized trials to compare sorafenib plus cisplatin and 5-FU with standard dose of cisplatin plus 5-FU in NPC are warranted.

Phase I and clinical pharmacology study of bevacizumab, sorafenib, and low-dose cyclophosphamide in children and young adults with refractory/recurrent solid tumors

PURPOSE

To determine the maximum-tolerated dose (MTD), dose-limiting toxicities (DLT), pharmacokinetics, and pharmacodynamics of sorafenib, bevacizumab, and low-dose oral cyclophosphamide in children and young adults with recurrent/refractory solid tumors.

EXPERIMENTAL DESIGN

Sorafenib dose was escalated from 90 to 110 mg/m(2) twice daily with fixed doses of bevacizumab at 5 mg/kg every 3 weeks and cyclophosphamide at 50 mg/m(2) daily. Once sorafenib's MTD was established, bevacizumab dose was escalated. Each course was of 21 days. Pharmacokinetics and pharmacodynamics studies were conducted during the first course.

RESULTS

Nineteen patients (11 males; median age, 9.2 years) received a median of four courses (range, 1-23). DLTs during course 1 included grade 3 rash (two), increased lipase (one), anorexia (one), and thrombus (one). With an additional 71 courses of therapy, the most common toxicities ≥ grade 3 included neutropenia (nine), lymphopenia (nine), and rashes (four). Five of 17 evaluable patients had partial tumor responses, and five had disease stabilization (>2 courses). Median day 1 cyclophosphamide apparent oral clearance was 3.13 L/h/m(2). Median day 1 sorafenib apparent oral clearance was 44 and 39 mL/min/m(2) at the 2 dose levels evaluated, and steady-state concentrations ranged from 1.64 to 4.8 mg/L. Inhibition of serum VEGF receptor 2 (VEGFR2) was inversely correlated with sorafenib steady-state concentrations (P = 0.019).

CONCLUSION

The recommended phase II doses are sorafenib, 90 mg/m(2) twice daily; bevacizumab, 15 mg/kg q3 weeks; and cyclophosphamide, 50 mg/m(2) once daily. This regimen is feasible with promising evidence of antitumor activity that warrants further investigation.

Dynamic contrast enhanced ultrasound assessment of the vascular effects of novel therapeutics in early stage trials

Imaging is key in the accurate monitoring of response to cancer therapies targeting tumour vascularity to inhibit its growth and dissemination. Dynamic contrast enhanced ultrasound (DCE ultrasound) is a quantitative method with the advantage of being non-invasive, widely available, portable, cost effective, highly sensitive and reproducible using agents that are truly intravascular. Under the auspices of the initiative of the Experimental Cancer Medicine Centre Imaging Network, bringing together experts from the UK, Europe and North America for a 2-day workshop in May 2010, this consensus paper aims to provide guidance on the use of DCE ultrasound in the measurement of tumour vascular support in clinical trials. Key Points • DCE ultrasound can quantify and extract specific blood flow parameters, such as flow velocity, relative vascular volume and relative blood flow rate. • DCE ultrasound can be performed repeatedly and is therefore ideally suited for pharmacokinetic and pharmacodynamic studies evaluating vascular-targeted drugs. • DCE ultrasound provides a reproducible method of assessing the vascular effects of therapy in pre-clinical and early clinical trials, which is easily translatable into routine clinical practice.

Evaluation of sorafenib for hepatocellular carcinoma by contrast-enhanced ultrasonography: A pilot study

AIM: To determine the usefulness of arrival time parametric imaging (AtPI) using contrast-enhanced ultrasonography (CEUS) with Sonazoid in evaluating early response to sorafenib for hepatocellular carcinoma (HCC).

METHODS: Fourteen advanced HCC patients who received sorafenib 400/800 mg/d for at least 4 wk and were followed up by CEUS were enrolled in this study. CEUS was performed before treatment and 2 and 4 wk after treatment, and images of the target lesion in the arterial phase were recorded for each patient. The images were analyzed by AtPI. Color mapping (CM) images obtained by AtPI were compared before and after the treatment. In these CM images, the mean arrival time of the contrast agent in the region of interest from the starting point [mean time (MT)] was calculated. In each patient, differences between MT before and MT 2 and 4 wk after the treatment were compared with responses evaluated 4-8 wk after the treatment by dynamic computed tomography (CT), and statistical analysis was performed. Modified response evaluation criteria in solid tumors was used for the response evaluation.

RESULTS: In CM images both 2 and 4 wk after the treatment, delays in the arrival time of the contrast agent were noted in 8 of the 14 patients. In the other 6 patients, no color changes were observed in the tumor, or red and/or yellow increase, suggesting a decrease in blood flow velocity between images 2 and 4 wk after the treatment and those before the treatment. Dynamic CT could be performed 4-8 wk after the treatment in 13 of the 14 patients. Median differences in the MT were 1.13 s and 1.015 s, 2 and 4 wk after the treatment, respectively, in the 8 patients who showed stable disease (SD)/partial response (PR) on dynamic CT. Median differences in the MT were -0.39 s and -0.95 s, 2 and 4 wk after the treatment, respectively, in the 5 patients who showed progressive disease (PD). Differences in the median MT between SD/PR and PD groups were significant 2 and 4 wk after the treatment with P = 0.019 and P = 0.028, respectively.

CONCLUSION: AtPI by CEUS using Sonazoid is suggested to be useful for evaluating early responses to sorafenib.