Journal of Medical Ultrasonics最新文献

Sonazoid, an ultrasound contrast agent, has been covered by insurance in Japan since January 2007 for the diagnosis of hepatic mass lesions and is widely used for diagnosing not only primary liver cancer but also liver metastases such as those from breast cancer and colorectal cancer. Contrast-enhanced ultrasound for breast mass lesions has been covered by insurance since August 2012 after phase II and phase III clinical trials showed that the diagnostic performance was significantly superior to that of B-mode and contrast-enhanced magnetic resonance imaging. This paper describes the principles of imaging techniques in contrast-enhanced ultrasonography including the filter, pulse inversion, amplitude modulation, and amplitude-modulated pulse inversion methods. The pulse inversion method, which visualizes the second-harmonic component using the nonlinear scattering characteristics of the contrast agent, is widely used regardless of the contrast agent and target organ because of its high resolution. Sonazoid has a stiffer shell and requires a higher acoustic amplitude than Sonovue to generate nonlinear vibrations. The higher transmitted sound pressure generates more tissue harmonic components. Since pulse inversion allows visualization of the tissue harmonic components, amplitude modulation and amplitude-modulated pulse inversion, which include few tissue harmonic components, are primarily used. Amplitude modulation methods detect nonlinear signals from the contrast agent in the fundamental band. The mechanism of the amplitude modulation is considered to be changes in the echo signal's phase depending on the sound pressure. Since the tissue-derived component is minor in amplitude modulation methods, good contrast sensitivity can be obtained.

This narrative review aims to describe the current status of contrast-enhanced ultrasound (CEUS) in characterizing renal cystic lesion. The imaging techniques usually performed for their evaluation are ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI) with different criteria of application based on the individual case and the purpose of the examination. Generally, US, as a non-ionizing examination, is the first imaging modality performed and therefore the one that incidentally detects cystic lesions. CT is the most performed imaging modality for cystic lesion assessment before MRI evaluation. It provides better characterization and management and has been introduced into the Bosniak classification. In this context, CEUS is making its way for its characteristics and represents the emerging technique in this field. With these premises, the authors analyze the role of CEUS in the evaluation of renal cysts, starting with an explanation of the technique, describe its main advantages and limitations, and end with a discussion of its application in the Bosniak classification and management, following the current major guidelines.

Purpose: This study aimed to establish criteria for defining "large" subchorionic hematoma (SCH) and assess its association with pregnancy complications.

Method: This was a retrospective cohort study conducted at our institution between 2019 and 2020. We compared the size of SCH between the pregnancy-related complication and non-complication groups, using two measurement methods. Receiver operating characteristic (ROC) curve analysis determined cutoff values. Additionally, we compared the occurrence of pregnancy complications among three groups: large SCH group (above the cutoff value), non-large SCH group (below the cutoff value), and non-SCH group.

Results: Of 1305 singleton pregnancies managed during the study, 80 cases were diagnosed with SCH. Pregnancy complications occurred in 15 patients. The patients with pregnancy complications had significantly larger SCH sizes with both measurement methods. For each method, the cutoff values calculated from the ROC curve analysis were as follows: Method 1, 25% (area under the ROC curve [AUC], 0.662); Method 2, 30% (AUC, 0.624). In Method 1, we found a significantly higher occurrence of preterm delivery in the large SCH group (24.1%) than in the non-large SCH (4.2%) and non-SCH groups (5.3%; all p < 0.01). In Method 2, there was a significantly higher occurrence of preterm delivery in the large SCH group (33.3%) than in the non-large SCH (6.5%) and non-SCH groups (5.3%; all p < 0.01).

Conclusion: Large SCHs may indicate a high risk of pregnancy-related complications. Among these, recognizing and managing cases that exceed the aforementioned cutoff value as high-risk cases may be beneficial for reducing pregnancy complications.

Advances in various imaging modalities for breast lesions have improved diagnostic capabilities not only for tumors but also for non-tumorous lesions. Contrast-enhanced ultrasound (CEUS) plays a crucial role not only in the differential diagnosis of breast lesions, identification of sentinel lymph nodes, and diagnosis of lymph node metastasis but also in assessing the therapeutic effects of neoadjuvant chemotherapy (NAC). In CEUS, two image interpretation approaches, i.e., qualitative analysis and quantitative analysis, are employed and applied in various clinical settings. In this paper, we review CEUS for breast lesions, including its various applications.