Shah, Amar S

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.

Abstract Variants of the shoulder are commonly encountered and may occasionally be confused with pathological conditions. Our goal is to provide an overview of common normal variants of the shoulder’s anatomical structures as well as any associated clinical or surgical relevance. Following a literature search of common variants of the shoulder and supporting structures, this review provides a summary of variants related to the scapular body, acromion, glenoid, coracoid, labrum, long head biceps tendon, glenohumeral ligamentous complex, and rotator cuff. The shoulder is composed of the glenohumeral, acromioclavicular, sternoclavicular, and scapulothoracic joints and their associated osseous, ligamentous, cartilaginous, and musculotendinous stabilizers. Anatomic variants about the shoulder, especially in the adolescent and young adult populations, are frequently encountered. An awareness of associated pathological conditions and an understanding of when variants might be clinically significant is important in interpreting radiological exams.