Ruddy, Liane

Interlobular septal thickening (ILST) is a feature on chest computed tomography (CT) that is characterized by abnormal widening of the interlobular septa, which are thin connective tissues that separate secondary pulmonary lobules within the lung parenchyma. They contain pulmonary venules and lymphatic vessels. On CT, these septa are normally not visible in healthy patients. However, various pulmonary pathologic conditions can lead to ILST. If present, ILST can be categorized into 3 different patterns based on its morphologic appearance: smooth, nodular, and irregular/fibrotic. Each pattern occurs from different disease processes with little overlap. In this pictorial essay, we review common and rare etiologies for each type of ILST. For each disease, we discuss relevant pathophysiology, epidemiology, risk factors, symptoms, physical exam findings, labs, and management. Subsequently, we present the ILST features along with the distribution (eg, unilateral, bilateral, central, peripheral) and ancillary imaging findings that can support the diagnosis. Finally, characteristic and high-resolution figures are presented.

AbstractAn in-depth understanding of portal venous anatomy, particularly its variants, is essential for interventional radiologists performing complex hepatobiliary procedures such as transjugular intrahepatic portosystemic shunt (TIPS) creation. Anatomical variations in the portal venous system occur in approximately 35% of the population, and failure to identify these variants can result in significant procedural complications including vascular injury and postprocedural liver failure. This article discusses the most common (types I–V) portal vein variants and the importance of their preprocedural identification, their potential impact on procedural outcomes, and the role of advanced imaging techniques in mitigating risks associated with these anatomical variations.