Posterior bladder layering of excreted 18F-FDG on PET/CT.
OBJECTIVE
This study was carried out to determine the frequency, characteristics and possible causes and clinical significance of occasionally observed posterior layering of excreted 2-deoxy-2-[F]fluoro-D-glucose (F-FDG) in the bladder.


METHODS
A review of 567 consecutive patients referred for positron emission tomography/computerized tomography studies was performed. Urinary bladder size was measured in patients with and without layering. Urine samples from two patients with layering were imaged ex vivo.


RESULTS
Twenty-four of 567 studies (4%) showed F-FDG posterior bladder layering. Mean volume+/-SD of the bladder was 175+/-161 ml in patients with layering and 93+/-83 ml in patients without layering. Urine samples collected from two randomly chosen patients with layering in vivo failed to show layering ex vivo.


CONCLUSIONS
Posterior F-FDG layering occurs in 4% of positron emission tomography/computerized tomography cases and highly correlates with bladder volume. The mechanism is hypothesized to be because of slow F-FDG excretion in patients with a distended urinary bladder resulting in delayed mixing with urine, but needs to be further investigated with a more comprehensive study.
Zeng
Wanzhen
W
Department of Radiology, Emory School of Medicine, Atlanta, Georgia, USA. Wanzhenzeng@gmail.com
Sepulveda
Julio N
JN
Nye
Jonathan
J
Votaw
John R
JR
Nieh
Peter T
PT
Carew
John
J
Schuster
David M
DM
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D001743:Urinary Bladder / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000503:physiopathology; D014556:Urine; D055815:Young Adult
D019788:Fluorodeoxyglucose F18