Contrast-enhanced ultrasound of pancreatic tumours

Power-Doppler-based NH002 microbubble sonoporation with chemotherapy relieves hypoxia and enhances the efficacy of chemotherapy and immunotherapy for pancreatic tumors

Pancreatic ductal adenocarcinoma (PDAC) poses challenges due to late-stage diagnosis and limited treatment response, often attributed to the hypoxic tumor microenvironment (TME). Sonoporation, combining ultrasound and microbubbles, holds promise for enhancing therapy. However, additional preclinical research utilizing commercially available ultrasound equipment for PDAC treatment while delving into the TME's intricacies is necessary. This study investigated the potential of using a clinically available ultrasound system and phase 2-proven microbubbles to relieve tumor hypoxia and enhance the efficacy of chemotherapy and immunotherapy in a murine PDAC model. This approach enables early PDAC detection and blood-flow-sensitive Power-Doppler sonoporation in combination with chemotherapy. It significantly extended treated mice's median survival compared to chemotherapy alone. Mechanistically, this combination therapy enhanced tumor perfusion and substantially reduced tumor hypoxia (77% and 67%, 1- and 3-days post-treatment). Additionally, cluster of differentiation 8 (CD8) T-cell infiltration increased four-fold afterward. The combined treatment demonstrated a strengthening of the anti-programmed death-ligand 1(αPDL1) therapy against PDAC. Our study illustrates the feasibility of using a clinically available ultrasound system with NH-002 microbubbles for early tumor detection, alleviating hypoxic TME, and improving chemotherapy and immunotherapy. It suggests the development of an adjuvant theragnostic protocol incorporating Power-Doppler sonoporation for pancreatic tumor treatment.

Imaging of pancreatic serous cystadenoma and common imitators

Pancreatic cystic neoplasms are lesions comprised of cystic components that show different biological behaviors, epidemiology, clinical manifestations, imaging features, and malignant potential and management. Benign cystic neoplasms include serous cystic neoplasms (SCAs). Other pancreatic cystic lesions have malignant potential, such as intraductal papillary mucinous neoplasms and mucinous cystic neoplasms. SCAs can be divided into microcystic (classic appearance), honeycomb, oligocystic/macrocystic, and solid patterns based on imaging appearance. They are usually solitary but may be multiple in von Hippel-Lindau disease, which may depict disseminated involvement. The variable appearances of SCAs can mimic other types of pancreatic cystic lesions, and cross-sectional imaging plays an important role in their differential diagnosis. Endoscopic ultrasonography has helped in improving diagnostic accuracy of pancreatic cystic lesions by guiding tissue sampling (biopsy) or cyst fluid analysis. Immunohistochemistry and newer techniques such as radiomics have shown improved performance for preoperatively discriminating SCAs and their mimickers.

Comments on and Illustrations of the EFSUMB CEUS Guidelines: Transabdominal and Endoscopic Ultrasound Features of Intrapancreatic Metastases and the Role of Multiparametric Imaging and EUS-Guided Sampling in Rare Pancreatic Tumors

A definite pathologic diagnosis of intrapancreatic metastasis is crucial for the management decision, i.e., curative or palliative surgery versus chemotherapy or conservative/palliative therapy. This review focuses on the appearance of intrapancreatic metastases on native and contrast-enhanced transabdominal ultrasound and endoscopic ultrasound. Differences and similarities in relation to the primary tumor, and the differential diagnosis from pancreatic carcinoma and neuroendocrine neoplasms are described. The frequency of intrapancreatic metastases in autopsy studies and surgical resection studies will be discussed. Further emphasis is placed on endoscopic ultrasound-guided sampling to confirm the diagnosis.

Cavernous hemangioma of an intrapancreatic accessory spleen mimicking a pancreatic tumor: A case report

BACKGROUND

Intrapancreatic accessory spleen (IPAS) is an uncommon condition, with the majority of cases presenting as solid lesions. Thus, this condition is frequently misdiagnosed as pancreatic solid neoplasm. Moreover, splenic cavernous hemangioma is a rare disorder, whereas lesions with a cystic appearance arising from IPAS have not been reported.

CASE SUMMARY

Herein, we present a case involving a 32-year-old male who had a complex cystic lesion in the tail of the pancreas revealed by conventional ultrasound. The lesion was misdiagnosed as a pancreatic cystadenoma because of its confusing anatomic location, as well as due to its peripheral nodular and internal septal enhancement patterns on contrast-enhanced ultrasound. After multidisciplinary discussion, the patient finally underwent laparoscopic pancreatic body and tail resections. Postoperative pathology demonstrated the lesion to be a cavernous hemangioma arising from the IPAS.

CONCLUSION

Cavernous hemangioma in the intrapancreatic accessory spleen may mimic pancreatic cystadenoma, which is a condition with the potential to be malignant. Imaging follow-ups or surgical interventions may be helpful for the exclusion of malignant risks in complicated cystic lesions, especially those with parietal and septal enhancements.

Diagnosing Pancreatic Adenocarcinoma With Contrast-Enhanced Ultrasonography: A Literature Review of Research in Europe and Asia

The National Cancer Institute names pancreatic cancer the 11^th most common type of cancer in the United States. However, even with a somewhat low prevalence, in 2017, the American Cancer Society reported pancreatic cancer as the fourth leading cause of cancer-related death. With a lack of symptomology and a broad range of risk factors, pancreatic cancer is frequently diagnosed in a later phase than many other types of cancers, thus resulting in higher metastasis along with a poorer prognosis. This highlights the need for early detection and diagnosis. Currently, abdominal ultrasound or contrast-enhanced CT imaging of the abdomen are standard of care. A new technology: contrast-enhanced ultrasound (CEUS), which employs contrast agents to act as acoustic enhancers for ultrasound, has FDA approval for use in hepatic and renal lesions, but not pancreatic. By examining seven individual studies from Europe and Asia, this review aims to examine the diagnostic value of CEUS to initially diagnose pancreatic adenocarcinomas, potentially followed by a biopsy to confirm, when compared against modalities currently used such as conventional ultrasound and CT imaging. CEUS would potentially be more accurate when compared to conventional ultrasound due to the addition of contrast, and when compared against CT and MRI, CEUS would be advantageous in its low cost, similar sensitivities, and specificities, limited renal toxicity, lack of ionizing radiation, short half-life, and its safe use in both adult and pediatric patients. Due to this, additional research is warranted for further FDA approval and future clinical implementation.

Intraoperative Characterization of Pancreatic Tumors Using Contrast-Enhanced Ultrasound and Shear Wave Elastography for Optimization of Surgical Strategies

OBJECTIVES

To evaluate intraoperative contrast-enhanced ultrasound (IoCEUS) and intraoperative shear wave elastography (IoSWE) for characterization of focal pancreatic lesions (FPLs) in correlation with postoperative histologic results. Thereby, the impact of intraoperative ultrasound (US) on pancreas surgery was evaluated.

METHODS

Intraoperative CEUS and SWE data from 54 patients, who underwent pancreas surgery between 2017 and 2019, were analyzed retrospectively. Ultrasound examinations were performed with multifrequency linear/T-shaped transducers (3-9 MHz) on a high-end US device (LOGIQ E9; GE Healthcare, Chicago, IL). To analyze FPL stiffness by SWE, regions of interest were placed to measure the shear wave speed (meters per second) and stiffness (kilopascals). After intravenous bolus injections of 2.4 to 10 mL of sulfur hexafluoride microbubbles, a dynamic analysis of FPL microvascularization from arterial to late phases was performed using IoCEUS considering hypoenhancement/irregular vascularization of macrocystic/small solid FPL malignancy criteria. Ultrasound findings were correlated with postoperative histologic results. The impact of intraoperative US on surgery was documented in each case.

RESULTS

Of 54 FPLs, IoCEUS could correctly characterize 39 of 39 malignant and 6 of 15 benign FPLs; IoSWE 29 of 39 as malignant and 7 of 15 as benign. Intraoperative CEUS's sensitivity was 100%; specificity, 40%; accuracy, 83.3%; positive predictive value, 81.3%; and negative predictive value, 100% (P < .05). Applying cutoff values of 3 m/s and 28.7 kPa, SWE's sensitivity was 74.4%; specificity, 46.7%; accuracy, 66.7%; positive predictive value; 78.4%; and negative predictive value, 41.2% for cancer detection (P < .05). The combined use of both techniques showed an accuracy rate of 76%, sensitivity of 74.4%, and specificity of 33.3%. In 29.6%, US results had an immediate impact on surgery.

CONCLUSIONS

Intraoperative SWE and CEUS are highly valuable techniques for intraoperative characterization of FPLs. Although IoCEUS proved to be superior to IoSWE, the combined use can be helpful in particular cases.

Feline abdominal ultrasonography: What's normal? What's abnormal? The pancreas

PRACTICAL RELEVANCE

Abdominal ultrasound plays a vital role in the diagnostic work-up of many cats presenting to general and specialist practitioners. Ultrasound examination of the pancreas is a vital part of the investigation into feline pancreatic disease.

CLINICAL CHALLENGES

Despite ultrasonography being a commonly used modality, many practitioners are not comfortable performing an ultrasound examination or interpreting the resulting images. Even for the experienced ultrasonographer, differentiating between incidental findings such as nodular hyperplasia and pathological changes such as neoplasia can be challenging.

AIM

This review, part of an occasional series on feline abdominal ultrasonography, discusses the ultrasonographic examination and appearance of the normal and diseased pancreas. Aimed at general practitioners who wish to improve their knowledge of and confidence in feline abdominal ultrasound, this review is accompanied by high-resolution images and videos available online as supplementary material.

EQUIPMENT

Ultrasound facilities are readily available to most practitioners, although use of ultrasonography as a diagnostic tool is highly dependent on operator experience.

EVIDENCE BASE

Information provided in this article is drawn from the published literature and the author's own clinical experience.

Pancreatic Ultrasound: State of the Art

An ultrasound (US) study is often the first imaging approach in patients with abdominal symptoms or signs related to abdominal diseases, and it is often part of the routine workup. The pancreatic gland, despite its retroperitoneal site, can be efficiently examined with US thanks to advances in US technologies. Nowadays, a pancreatic US study could be considered complete if multiparametric, including the use of Doppler imaging, US elastography, and contrast-enhanced imaging for the study of a pancreatic mass. A complete US examination could contribute to a faster diagnosis, especially if the pancreatic lesion is incidentally detected, addressing second-step imaging modalities correctly.

Management of Autoimmune Pancreatitis

Type 1 autoimmune pancreatitis (AIP) is an IgG-4-related systemic disease that can manifest as a pancreatic disorder or another disorder of presumed autoimmune origin. Type 2 disease is typically characterized by absent IgG-4-positive cells. As patients often present with acute pancreatitis, obstructive jaundice, or pancreatic mass, it is imperative to exclude malignancy, a more common diagnosis. AIP may respond to corticosteroids, and has a strong association with other immune-mediated diseases. Recent literature suggests the benefit of immune-modulating therapy, including rituximab, although no consensus exists. This review covers the essentials of diagnosis, but focuses primarily on management of AIP.