[CEUS-diagnosis of benign liver lesions]

Novel high-resolution contrast agent ultrasound techniques HiFR CEUS and SR CEUS in combination with shear wave elastography, fat assessment and viscosity of liver parenchymal changes and tumors

BACKGROUND

The continuous development of ultrasound techniques increasingly enables better description and visualization of unclear lesions. New ultrasound systems must be evaluated with regard to all these diagnostic possibilities.

METHODS

A multifrequency C1-7 convex probe (SC7-1M) with the new high-end system Resona A20 Series was used. Modern technologies, including HiFR CEUS, SR CEUS and multimodal tissue imaging with shear wave elastography (SWE), fat evaluation and viscosity measurements (M-Ref) were applied.

RESULTS

Of n = 70 (mean value 48,3 years±20,3 years, range 18-84 years) cases examined, a definitive diagnosis could be made in n = 67 cases, confirmed by reference imaging and/or follow-up. Of these, n = 22 cases were malignant changes (HCC (hepatocellular carcinoma) n = 9, CCC (cholangiocellular carcinoma) n = 3, metastases of colorectal carcinomas or recurrences of HCC n = 10). In all 12 cases of HCC or CCC, the elastography measurements using the shear wave technique (with values >2 m/s to 3.7 m/s) showed mean values of 2.3±0.31 m/s and a degree of fibrosis of F2 to F4. In n = 14 cases, changes in the fat measurement (range 0.51 to 0.72 dB/cm/MHz, mean values 0.58±0.12 dB/cm/MHz) in the sense of proportional fatty changes in the liver were detected. In the 4 cases of localized fat distribution disorders, the values were >0.7 dB/cm/MHz in the sense of significant fatty deposits in the remaining liver tissue. Relevant changes in the viscosity measurements with values >1.8 kPa were found in n = 31 cases, in n = 5 cases of cystic lesions with partially sclerosing cholangitis, in n = 13 cases of malignant lesions and in n = 9 cases post-interventionally, but also in n = 4 cases of benign foci with additional systemic inflammation.

CONCLUSIONS

The results are promising and show a new quality of ultrasound-based liver diagnostics. However, there is a need for further investigations with regard to the individual aspects, preferably on a multi-center basis.

Application of Quantitative Parameters of Contrast-Enhanced Ultrasound in Common Benign and Malignant Lesions in Pediatric Livers: A Preliminary Study

We aimed to investigate the diagnostic utility of quantitative parameters of contrast-enhanced ultrasound (CEUS) for benign and malignant liver lesions in pediatric patients. This was a single-center retrospective analysis of children with liver lesions who underwent CEUS at our hospital between July 2019 and February 2023. The CEUS perfusion patterns for all lesions were qualitatively analyzed using histopathology, contrast-enhanced magnetic resonance imaging, contrast-enhanced computed tomography, or long-term clinical follow-up as reference standards. The CEUS images were quantitatively analyzed using SonoLiver® software (TomTec Imaging Systems, Munich, Germany) to obtain data regarding quantitative parameters and dynamic vascular pattern (DVP) parametric images, including rise time (RT), time to peak (TTP), mean transit time (mTT), and maximum intensity (IMAX). Statistical analysis was carried out using Student's t-test and receiver operating characteristic (ROC) curve analysis to evaluate the diagnostic value of quantitative parameters. A total of 53 pediatric cases were included in this study, and 88.57% (31/35) of malignant lesions exhibited hyper-enhancement with rapid washout patterns; the same proportion of DVP parametric images exhibited washout patterns. Conversely, 94.44% (17/18) of benign lesions showed hyper-enhancement with slow washout patterns, and the same proportion of DVP parametric images showed no-washout patterns. RT, TTP, and mTT were significantly shorter in the malignant group than in the benign group (p < 0.05), while IMAX showed no significant difference (p > 0.05). ROC analysis indicated that mTT < 113.34 had the highest diagnostic value, with an area under the curve of 0.82. CEUS quantitative analysis had an accuracy of 98.11%, while qualitative analysis had an accuracy of 92.45%, with no statistically significant difference (p > 0.05). Quantitative analysis of CEUS provides valuable assistance in differentiating benign and malignant liver lesions in children. Among all quantitative parameters, mTT holds promise as a potentially valuable tool for identifying liver tumors.

Modified contrast-enhanced ultrasonography with the new high-resolution examination technique of high frame rate contrast-enhanced ultrasound (HiFR-CEUS) for characterization of liver lesions: First results

AIM

To examine to what extent the high frame rate contrast-enhanced ultrasound (HiFR) diagnostic enables the conclusive diagnosis of liver changes with suspected malignancy.

MATERIAL/METHODS

Ultrasound examinations were performed by an experienced examiner using a multifrequency probe (SC6-1) on a high-end ultrasound system (Resona 7, Mindray) to clarify liver changes that were unclear on the B-scan. A bolus of 1-2.4 ml of the Sulphur hexafluoride ultrasound microbubbles contrast agent SonoVue™ (Bracco SpA, Italy) was administered with DICOM storage of CEUS examinations from the early arterial phase (5-15 s) to the late phase (5-6 min). Based on the image files stored in the PACS, an independent reading was performed regarding image quality and finding-related diagnostic significance (0 not informative/non-diagnostic to 5 excellent image quality/confident diagnosis possible). References were clinical follow-up, if possible, comparison to promptly performed computed tomography or magnetic resonance imaging, in some cases also to histopathology.

RESULTS

We examined 100 patients (42 women, 58 men, from 18 years to 90 years, mean 63±13 years) with different entities of focal and diffuse liver parenchymal changes, which could be detected in all cases with sufficient image quality with CEUS and with high image quality with HiFR-CEUS. Proportionally septate cysts were found in n = 19 cases, scars after hemihepatectomy with local reduced fat in n = 5 cases, scars after microwave ablation in n = 19 cases, hemangiomas in n = 9 cases, focal nodular hyperplasia in n = 8 cases, colorectal metastases in n = 15 cases, hepatocellular carcinoma (HCC) in n = 11 cases, Osler disease in n = 8 cases. The size of lesions ranged from 5 mm to 200 mm with a mean value of 33.1±27.8 mm. Conclusive diagnoses could be made by the experienced investigator in 97/100 cases with CEUS, confirmed by reference imaging, in parts by histopathology or follow-up. The image quality for HiFR CEUS was rated with a score of 3 to 5; 62 cases were assessed with an average of good (4 points), 27 cases with very good (5 points), and in 11 cases (3 points) still satisfactory despite aggravated acoustic conditions. The specificity of HIFR-CEUS was 97%, the sensitivity 97%, the positive predictive value 94%, the negative predictive value 99% and the accuracy 97%.

CONCLUSION

HIFR-CEUS has demonstrated has demonstrated an improved image quality resulting in a high diagnostic accuracy. In the hands of an experienced investigator, HiFR-CEUS allows the assessment of focal and diffuse unclear liver parenchymal changes on B-scan and dynamic assessment of microcirculation in solid and vascular changes.

Multimodal Imaging under Artificial Intelligence Algorithm for the Diagnosis of Liver Cancer and Its Relationship with Expressions of EZH2 and p57

Objective

It aimed to explore the diagnostic efficacy of multimodal ultrasound images based on mask region with convolutional neural network (M-RCNN) segmentation algorithm for small liver cancer and analyze the expression of zeste gene enhancer homolog 2 (EZH2) and p57 (P57 Kip2) genes in cancer cells.

Methods

A total of 100 patients suspected of small liver cancer were randomly divided into Doppler group (color Doppler ultrasound examination), contrast group (contrast ultrasound examination), elastic group (ultrasound elastography examination), and multimodal group (combined examination of the three methods), with 25 patients in each group. Images were processed by the M-RCNN segmentation algorithm. The results of the pathological biopsy were used to evaluate the diagnostic efficacy of the four methods. The liver tissues were then extracted and divided into observation group 1 (lesion tissue specimen), observation group 2 (liver tissue around cancer lesion), and control group (normal liver tissue), and the expression activities of EZH2 and p57 genes in the three groups were analyzed.

Results

The accuracy of M-RCNN (97.23%) and average precision (AP) (71.90%) were higher than other methods (P < 0.05). Sensitivity (88.87%), specific degree of consistency (90.91%), accuracy (89.47%), and consistence (0.68) of the multimodal group were better than the other three groups (P < 0.05). Low and medium differentiated cancer tissues had an irregular shape, unclear boundary, uneven internal echo, unchanged/enhanced posterior echo, blood flow level 1∼2, elastic score 4∼5, and enhancement mode fast in and fast out. The positive expression rate of EZH2 in observation group 1 (75.95%) was higher than that in the other two groups, the positive expression rate of p57 in observation group 1 (80.79%) was lower than that in the other two groups, and the positive expression rate of p57 in the highly differentiated cancer foci (80.79%) was significantly lower than that in the middle and low differentiated cancer foci (P < 0.05).

Conclusions

M-RCNN segmentation algorithm had a better segmentation effect. Multimodal ultrasound had a good effect on the benign and malignant diagnosis of small liver cancer and had a high clinical application value. The high expression of EZH2 and the decreased expression of p57 can promote the occurrence of small hepatocellular carcinoma, and the deficiency of the P57 gene was related to the low differentiation of cancer cells.

Contrast-enhanced ultrasound perfusion imaging of organs

In multimodal radiologic imaging, contrast-enhanced ultrasound (CEUS) is increasingly used. One of the advantages of CEUS is the possibility of repeated application of contrast media without decreasing renal function or affecting the thyroid gland. Small solid liver lesions can be diagnosed and detected with high accuracy. Moreover, solid lesions in other abdominal organs can also be characterized. Frequent applications for solid lesions in the near field concern thyroid tumors and lymph nodes. For prostate diagnostics, CEUS can be used with an endorectal probe and perfusion imaging. This review explains how the additional (semi-)quantitative perfusion analysis, especially time-intensity curve (TIC) analyses, and wash-in/wash-out kinetics of integrated or external perfusion software programs facilitate new options in dynamic assessment of microvascularization during tumor follow-up care and even minimally invasive tumor therapy.

[Benign liver tumors : Diagnostics and treatment]

Benign liver tumors are often detected during routine ultrasound examinations or as an incidental finding in radiological imaging. Only very few benign liver tumors are at risk of becoming malignant. In the majority of cases the differentiation from malignant tumors is currently carried out using imaging procedures. In a few cases of diagnostic uncertainty, a transcutaneous liver biopsy can lead to clarification. If the suspicion of malignancy is substantiated or this cannot be excluded with absolute certainty, the tumor should be removed by partial liver resection.

[Benign liver tumors : Diagnostics and treatment]

Benign liver tumors are often detected during routine ultrasound examinations or as an incidental finding in radiological imaging. Only very few benign liver tumors are at risk of becoming malignant. In the majority of cases the differentiation from malignant tumors is currently carried out using imaging procedures. In a few cases of diagnostic uncertainty, a transcutaneous liver biopsy can lead to clarification. If the suspicion of malignancy is substantiated or this cannot be excluded with absolute certainty, the tumor should be removed by partial liver resection.