Published in:
01-05-2019 | Urography | Classics in Abdominal Radiology
The “phantom” calyx
Published in: Abdominal Radiology | Issue 5/2019
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A “phantom” calyx refers to the imaging finding of lack of contrast opacification of a calyx or portion of the collecting system, where one should be, within an otherwise well-opacified pelvicalyceal system [1]. This appearance most often reflects a process that has infiltrated or obliterated the collecting system element [1]. The appearance was initially described on excretory urography (EXU) [1], but it may also be appreciated on retrograde pyelography (Fig. 1), and CT and MR urography (Fig. 2). The phantom calyx may be caused by tumor (especially urothelial carcinoma of the renal pelvis), infection (especially renal tuberculosis), edema from acute pyelonephritis, stricture related to renal calculus disease or trauma, renal ischemia, renal contusion, a congenital anomaly of the collecting system, or technical under filling during a procedure[1‐3].
Fig. 1
An image from a left retrograde pyelogram showing no opacification of the upper pole calyx, a “phantom calyx” (red arrow), caused by an urothelial neoplasm
Fig. 2
Coronal reformatted image from the excretory phase of a CT urogram in another patient showing the absence of filling of the upper pole calyx (red arrow) from an infiltrating urothelial neoplasm
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