Quantitative 3-dimensional contrast echocardiographic determination of myocardial mass at risk and residual infarct mass after reperfusion: experimental canine studies with intravenous contrast agent NC100100

Contrast-Enhanced Intraoperative Ultrasonography with Kupffer Phase May Change Treatment Strategy of Metastatic Liver Tumors - A Single-Centre Prospective Study

Aim

To compare the diagnostic performance of contrast-enhanced intraoperative ultrasonography (CE-IOUS) with Kupffer phase in metastatic liver tumours.

Methods

Twenty-seven consecutive patients with liver metastasis were prospectively recruited from November 2019 to July 2020 in the Department of HPB, Beijing Hospital. MRI and Contrast Enhanced Ultrasonography (CEUS) were obtained preoperatively, and the diagnosis was made by radiologists independently and blindly. Intraoperative ultrasonography (IOUS) and CE-IOUS with Sonazoid were done by the same sophisticated surgeon and sonographer and Kupffer phase was used to detect lesions. The sensitivity and specificity to detect lesions were compared between different radiologic methods. Then, the changes in treatment strategy due to CE-IOUS with Sonazoid were analysed.

Results

Twenty-seven patients were included. In MRI, 91 lesions were detected with sensitivity 93.3% (70/75) and specificity 68.8% (11/16). In CEUS, it was 97.1% (68/70) and 86.7% (13/15) in 85 lesions. Meanwhile, in the Kupffer phase in CE-IOUS, 99 lesions were found and 8 new lesions were discovered in 7 cases, with sensitivity 97.5% (80/82) and specificity 94.1% (16/17). The four imaging methods showed no statistic significance in sensitivity and specificity in detecting lesions (Cochran’s Q 10.825, P=0.055). Treatment strategies were altered in 7 patients, 6 achieved R0 resection or ablation, and 1 patient changed from planned R0 resection to palliative surgery.

Conclusion

CE-IOUS may play a similar or even better role than other radiological methods in diagnosing liver metastasis. The CE-IOUS using Sonazoid demonstrated a high sensitivity and specificity for finding occult metastases intraoperatively and changing the treatment strategy.

New malignant grading system for hepatocellular carcinoma using the Sonazoid contrast agent for ultrasonography

BACKGROUND

The ultrasonography contrast agent Sonazoid provides parenchyma-specific contrast imaging (Kupffer imaging) based on its accumulation in Kupffer cells. This agent also facilitates imaging of the fine vascular architecture in tumors through maximum intensity projection (MIP). We examined the clinical utility of the malignancy grading system for hepatocellular carcinoma (HCC) using a combination of 2 different contrast-enhanced ultrasonography images.

METHODS

We studied 121 histologically confirmed cases of HCC (well-differentiated, 45; moderately differentiated, 70; poorly differentiated, 6). The results of Kupffer imaging were classified as (1) iso-echoic pattern or (2) hypo-echoic pattern. The MIP patterns produced were classified into one of the following categories: fine, tumor vessels were not clearly visualized and only fine vessels were visualized; vascular, tumor vessels were visualized clearly; irregular, tumor vessels were thick and irregular. Based on the combined assessment of Kupffer imaging and the MIP pattern, the samples were classified into 4 grades: Grade 1 (iso-fine/vascular), Grade 2 (hypo-fine), Grade 3 (hypo-vascular), and Grade 4 (hypo-irregular).

RESULTS

The distribution of moderately and poorly differentiated HCCs was as follows: Grade 1, 4 % (1/24); Grade 2, 52 % (15/29); Grade 3, 85 % (44/52); and Grade 4, 100 % (16/16). The grading system also predicted portal vein invasion in 72 resected HCCs: Grade 1, 0 % (0/4); Grade 2, 13 % (1/8); Grade 3, 23 % (11/48); and Grade 4, 67 % (8/12).

CONCLUSIONS

This new malignant grading system is useful for estimation of histological differentiation and portal vein invasion of HCC.

Usefulness of Sonazoid contrast-enhanced ultrasonography for hepatocellular carcinoma: comparison with pathological diagnosis and superparamagnetic iron oxide magnetic resonance images

OBJECTIVE

We investigated the usefulness of Sonazoid contrast-enhanced ultrasonography (Sonazoid-CEUS) in the diagnosis of hepatocellular carcinoma (HCC). The examination was performed by comparing the images during the Kupffer phase of Sonazoid-CEUS with superparamagnetic iron oxide magnetic resonance (SPIO-MRI).

METHODS

The subjects were 48 HCC nodules which were histologically diagnosed (well-differentiated HCC, n=13; moderately differentiated HCC, n=30; poorly differentiated HCC, n=5). We performed Sonazoid-CEUS and SPIO-MRI on all subjects. In the Kupffer phase of Sonazoid-CEUS, the differences in the contrast agent uptake between the tumorous and non-tumorous areas were quantified as the Kupffer phase ratio and compared. In the SPIO-MRI, it was quantified as the SPIO-intensity index. We then compared these results with the histological differentiation of HCCs.

RESULTS

The Kupffer phase ratio decreased as the HCCs became less differentiated (P<0.0001; Kruskal-Wallis test). The SPIO-intensity index also decreased as HCCs became less differentiated (P<0.0001). A positive correlation was found between the Kupffer phase ratio and the SPIO-MRI index (r=0.839). In the Kupffer phase of Sonazoid-CEUS, all of the moderately and poorly differentiated HCCs appeared hypoechoic and were detected as a perfusion defect, whereas the majority (9 of 13 cases, 69.2%) of the well-differentiated HCCs had an isoechoic pattern. The Kupffer phase images of Sonazoid-CEUS and SPIO-MRI matched perfectly (100%) in all of the moderately and poorly differentiated HCCs.

CONCLUSION

Sonazoid-CEUS is useful for estimating histological grading of HCCs. It is a modality that could potentially replace SPIO-MRI.

Contrast-enhanced intraoperative ultrasonography equipped with late Kupffer-phase image obtained by sonazoid in patients with colorectal liver metastases

AIM: To find occult metastases during hepatectomy in patients with colorectal cancer liver metastases (CRCLM), contrast-enhanced intraoperative ultrasonography (CE-IOUS) was performed using a new microbubble agent, sonazoid, which provides a parenchyma-specific contrast image based on its accumulation in the Kupffer cells.

METHODS: Eight patients with CRCLM underwent CE-IOUS using sonazoid before hepatectomy. The liver was investigated during a late Kupffer-phase imaging, which is a valuable characteristic of sonazoid.

RESULTS: CE-IOUS using sonazoid provided the early vascular- and sinusoidal-phase images for

10 min followed by the late Kupffer-phase image up to 30 min after the injection of sonazoid. IOUS did not provide new findings of metastatic lesion in the 8 patients. However, during the late Kupffer-phase image of sonazoid, a metastatic lesion was newly found in two of the 8 patients. These newly detected lesions were removed by an additional hepatectomy and histopathologically diagnosed as a metastasis.

CONCLUSION: CE-IOUS using sonazoid can allow surgeons to investigate the whole liver with enough time and to find new metastases intraoperatively.

Characterization of tumor imaging with microbubble-based ultrasound contrast agent, sonazoid, in rabbit liver

In order to investigate improvement of hepatic tumor detectability by Sonazoid with phase inversion imaging, the contrast effects on the liver of metastatic carcinoma-model rabbits were evaluated by videodensitometry and visual assessment. Correlation between the contrast enhancement of Sonazoid and histopathology was examined using the same animals. Electron microscopy was performed on hepatic tissue from another healthy rabbits to identify the distribution of Sonazoid microbubbles. As a result, all tumors were smaller than 12 mm in diameter, and after intravenous injection of Sonazoid, they were surrounded with a ring of enhanced signal during the early phase (up to 30 s), followed by a clear contrast defect during the delayed phase (after 10 min). Histopathologic observation revealed that the ring-enhancement was caused by neovasculature in the tumor, and the contrast defects corresponded to living and dead parts of tumors, which lack Kupffer cells. Videodensitometric differences between tumor and healthy tissue markedly increased at delayed phase, and visual detectability of tumors was improved when Sonazoid was used. Ultrastructural analysis showed microbubble-like structures in Kupffer cells, which indicated that Sonazoid microbubbles were taken up with these cells. In conclusion, Sonazoid, used with phase inversion imaging, greatly increases the detectability of small hepatic tumors by highlighting neovascularity at early phase and providing clear contrast defects due to absence of Kupffer cells, which take up Sonazoid microbubbles, at delayed phase.

Live Real-time Three-dimensional Echocardiography for the Visualization of Myocardial Perfusion–A Pilot Study in Open-chest Pigs

Visualization of myocardial perfusion is possible in both 2-dimensional and from reconstructive 3-dimensional echocardiography. We present the findings of our experimental pilot study of myocardial perfusion detection using live real-time 3-dimensional echocardiography in an animal model.

Gray-scale liver enhancement with Sonazoid (NC100100), a novel ultrasound contrast agent; detection of hepatic tumors in a rabbit model

The liver contrast effects of Sonazoid in two ultrasonographic imaging modes, gray-scale conventional and harmonic, were examined as a time-related study in normal rabbits, and evaluated quantitatively and visually with tumor-model rabbits to estimate the diagnostic potential. Peak enhancement of vessels and parenchyma was observed 1 min after injection in both modes, although signal enhancement in the parenchyma lasted for 120 min compared with rapid decay (5-10 min) in vessels. When Sonazoid was intravenously injected into metastatic carcinoma-model (VX-2) rabbits, all hepatic tumors showed ring enhancement in the early phase followed by clear contrast defects in the delayed phase, because signal enhancement remained only in normal parenchyma. Visual analysis scores for the diagnosis of tumors were improved by Sonazoid injection, and the videodensitometric differences between tumor and normal tissues were significantly greater after injection. Although the harmonic mode tended to show better contrast effects, the conventional mode provided significant contrast enhancement in this hepatic tumor-model. Sonazoid might be useful for the detection of undifferentiated tumors in the liver by making it possible to visualize neovascularity in the early phase and clear contrast defects in the delayed phase, not only in the harmonic but also in the conventional mode.

Quantitative assessment of left ventricular perfusion defects using real-time three-dimensional myocardial contrast echocardiography

Quantitative assessment of perfusion defects with myocardial contrast echocardiography can be a valuable tool in the evaluation of patients with coronary artery disease. However, the use of 2-dimensional echocardiography for this purpose is limited to a restricted number of imaging planes. Real-time 3-dimensional echocardiography (RT3D) is a novel technique that provides instantaneous volumetric images. The aim of this study was to validate the use of RT3D for the quantitative assessment of myocardial perfusion defects in a model of acute coronary occlusion. To this end, 20 sheep underwent acute ligation of the left anterior descending (n = 14) or the posterior branch of the circumflex (n = 6) artery under general anesthesia. The RT3D images were obtained after left atrial injection of the contrast agent EchoGen (perflenapent emulsion; 0.8-1 mL). Evans blue dye was injected into the occluded coronary artery for subsequent anatomic identification of underperfused myocardium. The mass of the entire left ventricle and of the underperfused myocardial region were measured after death. Blinded off-line calculation of left ventricular (LV) mass and perfusion-defect mass from RT3D images were performed using an interactive aided-manual tracing technique. Total LV mass ranged from 68 to 141 g (mean plus minus SD: 92 +/- 24 g). The mass of the perfusion defect ranged from 0 to 43 g (mean +/- SD: 16 +/- 9 g) or 0 to 36% of total LV mass (mean +/- SD: 18% +/- 9%). The RT3D estimation of total LV mass strongly correlated with the anatomic measurement (r = 0.91; y = -2.54 + 1.04x; standard error of the estimate [SEE] = 11.9 g). The RT3D calculation of the mass of underperfused myocardium also strongly correlated with the anatomic measurement, both in absolute terms (r = 0.96; y = 2.01 + 0.87x; SEE = 2.2 g) and when expressed as percentage of total LV mass (r = 0.96; y = 0.11 + 1.02x; SEE = 2.8%). Hence, RT3D with myocardial contrast opacification accurately predicts the amount of underperfused myocardium in an animal model of acute coronary occlusion. This technique may therefore be useful for the quantitative assessment of myocardial perfusion defects in patients with coronary artery disease.

Improved 3-D-echocardiographic endocardial border delineation using the contrast agent FS069 (Optison) transesophageal studies in a porcine model

3-D echocardiography has the potential for quantitative assessment of regional wall motion. However, the 3-D procedures used to date do not provide the same spatial and temporal resolution as 2-D echocardiography, which results in problems with border delineation of the endocardium. There are, as yet, few studies testing if the use of contrast agent can improve endocardial definition in the 3-D data set. FS069 (Optison) was used for the first time for this purpose in the present study. A total of 12 mechanically-ventilated pigs were examined by transesophageal 3-D echocardiography, 1. using fundamental imaging and 2. following left-atrial injection of FS069 (Optison). The left ventricle was analyzed using an 18-segment model. Score with the value 0 (not visible), 1 (moderately visible) and 2 (well defined) were used to rate endocardial definition. All segments were assessed both end-diastolic and end-systolic. Various LV regions were examined by grouping segments (anterior/lateral/inferior and basal/mid-ventricular/apical). Using the contrast agent, the proportion of nonvisible segments fell diastolic from 40 (18.5%) to 15 (6.9%), and systolic from 26 (12.0%) to 11 (5.1%). The proportion of well defined segments increased diastolic from 62 (28.7%) to 108 (50%) and systolic from 73 (33.8%) to 123 (56.9%). The mean visibility score increased diastolic from 1.10 +/- 0.68 to 1.43 +/- 0.62 (p < 0.001), systolic from 1.22 +/- 0.64 to 1.52 +/- 0.59 (p < 0.001). The benefit was greatest in regions where the visibility score was lowest without contrast: in the area of the lateral wall and systolic near the apex. In conclusion, the use of FS069 (Optison) results in significantly better endocardial delineation in the 3-D data set. This could be important in future for the 3-D echocardiographic assessment of regional wall motion.

Recent advances in myocardial contrast echocardiography

Myocardial contrast echocardiography (MCE) has undergone many advances in the past several years through remarkable developments in contrast agent and ultrasound equipment technology. Microbubble ultrasound contrast agents can now safely transit the pulmonary circulation to provide opacification of the left ventricular cavity, improved endocardial border definition, and detection of myocardial perfusion. The role of contrast echocardiography in enhancing technically difficult images is now well established in clinical practice, and has proven especially useful in the stress and intensive care unit settings. Major progress has been made in the application of MCE for myocardial perfusion assessment in acute and chronic ischemic heart disease syndromes, and comprises the focus of this review. Advances in novel applications of contrast echocardiography, including targeted delivery of genetic and pharmaceutical materials, have also occurred, but remain in a preclinical phase. In summary, the combination of recent innovations in ultrasound equipment, and microbubble acoustics, allows for exciting exploration of the expanding role of contrast echocardiography in clinical practice.