Pancreatic surgery is considered one of the most technically challenging surgical procedures, despite the evolution of modern techniques. Neoplasms remain the most common indication for pancreatic surgery, although inflammatory conditions may also prompt surgical evaluation. The choice of surgical procedure depends on the type and location of the pathologic finding because different parts of the pancreas have separate vascular supplies that may be shared by adjacent organs. The surgical approach could be conventional or minimally invasive (laparoscopic, endoscopic, or robotic assisted). Because of the anatomic complexity of the pancreatic bed, perioperative complications may be frequently encountered and commonly involve the pancreatic-biliary, vascular, lymphatic, or bowel systems, irrespective of the surgical technique used. Imaging plays an important role in the assessment of suspected postoperative complications, with CT considered the primary imaging modality, while MRI, digital subtraction angiography, and molecular imaging are considered ancillary diagnostic tools. Accurate diagnosis of postoperative complications requires a solid understanding of pancreatic anatomy, surgical indications, normal postoperative appearance, and expected postsurgical changes. The practicing radiologist should be familiar with the most common perioperative complications, such as anastomotic leak, abscess, and hemorrhage, and be able to differentiate these entities from normal anticipated postoperative changes such as seroma, edema and fat stranding at the surgical site, and perivascular soft-tissue thickening. In addition to evaluation of the primary operative fossa, imaging plays a fundamental role in assessment of the adjacent organ systems secondarily affected after pancreatic surgery, such as vascular, biliary, and enteric complications. Published under a CC BY 4.0 license. Test Your Knowledge questions are available in the supplemental material. See the invited commentary by Winslow in this issue.

Disease spread in the abdomen and pelvis generally occurs in a predictable pattern in relation to anatomic landmarks and fascial planes. Anatomically, the abdominopelvic cavity is subdivided into several smaller spaces or compartments by key ligaments and fascial planes. The abdominal cavity has been traditionally divided into peritoneal, retroperitoneal, and pelvic extraperitoneal spaces. Recently, more clinically relevant classifications have evolved. Many pathologic conditions affect the abdominal cavity, including traumatic, inflammatory, infectious, and neoplastic processes. These abnormalities can extend beyond their sites of origin through various pathways. Identifying the origin of a disease process is the first step in formulating a differential diagnosis and ultimately reaching a final diagnosis. Pathologic conditions differ in terms of pathways of disease spread. For example, simple fluid tracks along fascial planes, respecting anatomic boundaries, while fluid from acute necrotizing pancreatitis can destroy fascial planes, resulting in transfascial spread without regard for anatomic landmarks. Furthermore, neoplastic processes can spread through multiple pathways, with a propensity for spread to noncontiguous sites. When the origin of a disease process is not readily apparent, recognizing the spread pattern can allow the radiologist to work backward and ultimately arrive at the site or source of pathogenesis. As such, a cohesive understanding of the peritoneal anatomy, the typical organ or site of origin for a disease process, and the corresponding pattern of disease spread is critical not only for initial diagnosis but also for establishing a road map for staging, anticipating further disease spread, guiding search patterns and report checklists, determining prognosis, and tailoring appropriate follow-up imaging studies. ^©RSNA, 2024 Supplemental material is available for this article.

Cholecystectomy is one of the most performed surgical procedures. The safety of this surgery notwithstanding, the sheer volume of operations results in a notable incidence of post-cholecystectomy complications. Early and accurate diagnosis of such complications is essential for timely and effective management. Imaging techniques are critical for this purpose, aiding in distinguishing between expected postsurgical changes and true complications. This review highlights current knowledge on the indications for cholecystectomy, pertinent surgical anatomy and surgical technique, and the recognition of anatomical variants that may complicate surgery. The article also outlines the roles of various imaging modalities in identifying complications, the spectrum of possible postsurgical anatomical changes, and the implications of such findings. Furthermore, we explore the array of complications that can arise post-cholecystectomy, such as biliary system injuries, gallstone-related issues, vascular complications, and the formation of postsurgical collections. Radiologists should be adept at identifying normal and abnormal postoperative findings to guide patient management effectively. Graphical abstract

Primary liver cancer is among the most common cancers globally. It is the sixth-most common malignancy encountered and the third-most common cause of cancer-related death. Hepatocellular carcinoma (HCC) is the most common primary liver malignancy, accounting for about 90% of primary liver cancers. The majority of HCCs occur in patients with underlying cirrhosis, which results from chronic liver diseases such as fatty liver, hepatitis B and hepatitis C infections, and chronic alcohol use, which are the leading causes. The obesity pandemic has led to an increased prevalence of nonalcoholic fatty liver disease (NAFLD), which leads to nonalcoholic steatohepatitis and could progress to cirrhosis. As HCC is among the most common cancers and occurs in the setting of chronic liver disease in most patients, screening the population at risk could help in early diagnosis and management, leading to improved survival. Screening for HCC is performed using biochemical marker testing such as α-fetoprotein (AFP) and cross-sectional imaging. It is critical to emphasize that HCC could potentially occur in patients without cirrhosis (non-cirrhotic HCC), which can account for almost 20% of all HCCs. The lack of cirrhosis can cause a delay in surveillance, which could potentially lead to diagnosis at a later stage, worsening the prognosis for such patients. In this article, we discuss the diagnosis of cirrhosis in at-risk populations with details on the different modalities available for screening HCC in patients with cirrhosis, emphasizing the role of abdominal ultrasounds, the primary imaging modality in HCC screening.

The corpus callosum (CC) is the largest interhemispheric commissure connecting the neocortical areas of the two cerebral hemispheres. The spectrum of anomalies of the CC includes agenesis, which may be complete or partial, and hypoplasia. The callosal agenesis may be isolated or may be associated with other abnormalities. Nonvisualization of cavum septum pellucidum and colpocephaly are important signs in the axial view which aid in the diagnosis. Demonstrating the absence of CC in mid-sagittal plane is the gold standard. We report a case of isolated complete corpus callosal agenesis diagnosed antenatally in the third trimester with a brief review of ultrasound findings in corpus callosal agenesis.

Sirenomelia is a rare congenital anomaly characterized by a single lower extremity which is associated with abnormalities in other organ systems, commonly affecting the gastrointestinal and the urogenital systems. It is sporadic with no increased risk in subsequent pregnancies. In almost all the cases of sirenomelia, a single umbilical artery (SUA) is present which arises from the abdominal aorta. Sirenomelia can be confidently diagnosed in the first trimester while the diagnosis in the second and third trimesters is rendered difficult due to the lack of amniotic fluid in the later gestation. Transvaginal ultrasound and color Doppler have a key role in making the diagnosis and 3D ultrasound helps in better demonstrating the abnormality.