Contrast-enhanced ultrasound using the ultrasound contrast agent Sonazoid has been covered by insurance for focal breast mass lesions since August 2012. Sonazoid is based on microbubbles (diameter of 2-3 μm) containing perflubutane. Imaging of nonlinear signals generated by the resonance of the bubbles due to ultrasound irradiation of middle or low pressure creates a contrast effect, which yields an excellent real-time contrast image. According to the diagnostic criteria, a lesion is likely to be benign if it is stained uniformly or not at all, and it is likely to be malignant if it is stained unevenly. It is also a finding of malignancy if it is accompanied by a staining defect or if it is stained beyond the range of the lesion determined by the B-mode image. We also discuss imaging methods and clinical applications of contrast-enhanced ultrasound for breast lesions.

Improvements in ultrasound diagnostic devices and ultrasound probes have enabled the widespread use of ultrasonography for assessments of the body surface area. Ultrasonography is minimally invasive, and therefore scrotal ultrasonography has been used since its development to examine testicular diseases. Recently, however, improvements in ultrasound image quality have enabled closer observation of the inside of the scrotum. In this article, I present scrotal ultrasound findings and points of differentiation in scrotal (e.g.,testis, epididymis, spermatic cord) diseases with the aim of further advancing scrotal ultrasonography from its current state.

Point-of-care ultrasound (POCUS) is useful for initial management of shock. Focused assessment with sonography for trauma (FAST) is performed for the rapid detection of cardiac tamponade, hemothorax, and hemoperitoneum, which can cause shock. Many clinical studies have shown the effectiveness and feasibility of cardiac POCUS performed by clinicians who are not specialized in echocardiography, which is now called focused cardiac ultrasound (FOCUS). Rapid ultrasound in shock (RUSH) is a comprehensive assessment method based on the classification of shock. POCUS is also useful for the rapid assessment of dyspnea and the confirmation and guidance of procedures in acute care settings. A POCUS framework based on the airway, breathing, and circulation approach (ABC-POCUS) systematically lays out all POCUS applications that are useful for the initial management of shock and dyspnea. It is appropriate to select POCUS applications from the framework or to use the framework as a protocol based on the clinical reasoning.

Purpose: We evaluated the efficacy of fusion imaging combining contrast-enhanced ultrasonography (CEUS) images and arterial phase contrast-enhanced CT (CECT) or hepatobiliary phase magnetic resonance imaging with gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (EOB-MRI) images for the early evaluation of the effectiveness of radiofrequency ablation (RFA) for small hypervascular hepatocellular carcinoma (HCC) with iso-echoic or unclear margins on conventional US. Methods: Forty HCCs (22 iso-echoic and 18 unclear margin lesions) with mean diameters of 13.7 mm were treated using RFA under the guidance of fusion imaging with CEUS. The adequacy of RFA was evaluated using fusion imaging with CEUS 1 day after RFA. CECT or EOB-MRI was performed 1 month after RFA. We reviewed the images obtained using both modalities. Results: When the 1-month CECT or EOB-MRI scans were used as the reference standard, the sensitivity, specificity, and accuracy of the 1-day fusion imaging for the diagnosis of the adequate ablation of these HCCs were 97, 100, and 98%, respectively; the kappa value for the agreement between the findings using the two modalities was 0.655. Conclusion: Fusion imaging with CEUS appears to be a useful method for the early evaluation of the efficacy of RFA for the treatment of HCCs with iso-echoic or unclear margins on conventional US.

A woman in her 50s presented to our clinic with a low-density area detected in hepatic segment 6 on unenhanced computed tomography. A low-echoic nodule with a clear border was observed on ultrasonography. Contrast-enhanced ultrasonography (CEUS) showed a meandering linear contrast enhancement pattern flowing into the nodule on vascular imaging in the arterial phase and a strong homogeneous enhancement pattern on perfusion imaging. The contrast enhancement pattern was relatively prolonged in the portal phase, and washout was not observed. In accumulation imaging, a blood vessel structure with a spoke-wheel pattern was identified. In the post-vascular phase, a clear defect with an irregular border measuring 17 mm was noted. After partial hepatectomy, a neuroendocrine tumor (NET) (G2) was diagnosed. The typical B-mode findings of NET-associated liver metastatic tumors are known to be uniform and slightly echogenic masses. CEUS findings consist of a uniformly strong enhancement pattern in the arterial phase, washout pattern in the portal phase, and a clear defect in the post-vascular phase. Differential diagnosis between metastatic NET and hepatocellular carcinoma (HCC) or focal nodular hyperplasia (FNH) is essential. Features that can be used to differentiate these are that HCC shows a relatively late washout and FNH often shows a spoke-wheel pattern on color Doppler and accumulation imaging in CEUS. However, some cases of FNH show a defect enhancement pattern in the post-vascular phase. We report a case of hepatic metastasis of NET that showed a spoke-wheel enhancement pattern on CEUS.