Duodenum: MDCT of acute conditions.

Multidetector computed tomography (MDCT) is the technique of choice for evaluating patients with acute abdominal pain. As the jejunum, ileum, and colon comprise the majority of the gastrointestinal tract, radiologists may potentially neglect the duodenum. However, the duodenum is a complex structure that can be affected by both intraperitoneal and extraperitoneal processes due to its central location and proximity to numerous upper abdominal structures.

Neoplastic and proliferative disorders of the perinephric space.

The perinephric space is a well-marginated central compartment of the retroperitoneum, located between the anterior and posterior pararenal spaces. Various neoplastic and proliferative disorders can affect the perinephric space, and there is a wide array of imaging findings. Although many perinephric lesions may extend directly from the kidney and adrenal gland, other lesions occur in the perinephric space due to haematogenous spread, as part of a systemic disease, or by extension from an adjacent retroperitoneal compartment.

Acute conditions affecting the perinephric space: imaging anatomy, pathways of disease spread, and differential diagnosis.

The perinephric space is an important, central compartment of the retroperitoneum which may host various acute conditions. Imaging evaluation of the perinephric space requires an understanding of its anatomy and the pathways of disease spread to and from other retroperitoneal compartments. Numerous acute conditions can affect the perinephric space and may occur in isolation, extend from nearby retroperitoneal structures, or be part of a systemic condition.