Anzeige
Erschienen in:
01.08.2015 | Classics in Abdominal Imaging
The “bear paw” sign
Erschienen in: Abdominal Radiology | Ausgabe 6/2015
Einloggen, um Zugang zu erhaltenExcerpt
The “bear paw” (Fig. 1A, B) metaphorically describes the CT appearance of a kidney diffusely involved with xanthogranulomatous pyelonephritis (XGP), a chronic inflammatory process arising from an incomplete immune response to chronic infection [1, 2]. The bear’s paw pattern reflects replacement of the renal parenchyma by hypoattentuting masses arranged in a “hydronephrotic” pattern (Fig. 2) [3].
Fig. 1
A “Bear paws”! The grizzly bear; the narrative of a hunter naturalist, historical, scientific and adventurous (1909) by Wright, William H. (William Henry), 1856–1934, published by New York, C. Scribner’s sons (http://commons.wikimedia.org/wiki/File:Bear_paws.jpg), accessed 30 December 2014. B Brown Bear, U.S. Fish and Wildlife Service (http://digitalmedia.fws.gov/cdm/singleitem/collection/natdiglib/id/5778/rec/1), accessed 30 December 2014.
Fig. 2
Unenhanced axial CT image at the level of the mid right kidney reveals a centrally obstructing stone, with replacement of the renal parenchyma by hypoattenutating collections in a “hydronephrotic” pattern. The appearance is characteristic of XGP, and resembles the bear paws in Fig. 1.
× ![]()
× ![]()
…