Perirenal fat stranding on CT: is there an association with bladder outlet obstruction?
OBJECTIVE
To determine the association between perirenal fat stranding (PFS) on CT and bladder outlet obstruction (BOO).


METHODS
CT scans from 122 patients who had undergone urodynamic study for lower urinary tract symptoms (LUTS) were registered after exclusion of patients with renal or retroperitoneal disease. Images were independently reviewed by two radiologists and compared with those of 244 age- and sex-matched control patients without LUTS. The PFS severity was scored on a four-point scale, and the interobserver agreement was assessed with kappa statistics. The severity score and incidence was compared between the groups, and the association with baseline characteristics was analyzed. For the LUTS group, an association between PFS severity and urodynamic and laboratory data was evaluated.


RESULTS
PFS was more frequent and more severe in the LUTS group than in the control group (p-value < 0.001); its presence was significantly associated with male gender and older age (p-value < 0.001). PFS was predominantly bilateral in both groups (80.1-93.2%). In the LUTS group, PFS severity scores were significantly correlated with the maximum flow rate, maximum detrusor pressure and estimated glomerular filtration rate (p-value < 0.001). Interobserver agreements were excellent for PFS presence (κ = 0.883) and severity (κ = 0.816).


CONCLUSIONS
Severe PFS was observed in older, male patients with LUTS. PFS severity was associated with the degree of BOO and impaired renal function.


CONCLUSIONS
Recognition of PFS on the CT scan may warrant further evaluation of BOO and appropriate management to prevent renal impairment.
Department of Radiology, Anam Hospital, Korea University College of Medicine, Seoul, Republic of Korea.
Na Y
NY
Han
Department of Radiology, Anam Hospital, Korea University College of Medicine, Seoul, Republic of Korea.
Deuk J
DJ
Sung
Department of Radiology, Anam Hospital, Korea University College of Medicine, Seoul, Republic of Korea.
Min J
MJ
Kim
Department of Radiology, Anam Hospital, Korea University College of Medicine, Seoul, Republic of Korea.
Beom J
BJ
Park
Department of Radiology, Anam Hospital, Korea University College of Medicine, Seoul, Republic of Korea.
Ki C
KC
Sim
Department of Radiology, Anam Hospital, Korea University College of Medicine, Seoul, Republic of Korea.
Sung B
SB
Cho
D000273:Adipose Tissue / Q000000981:diagnostic imaging*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007668:Kidney / Q000000981:diagnostic imaging*; D059411:Lower Urinary Tract Symptoms / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011856:Radiographic Image Enhancement; D012189:Retrospective Studies; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed; D001743:Urinary Bladder / Q000000981:diagnostic imaging; D001748:Urinary Bladder Neck Obstruction / Q000000981:diagnostic imaging*; D014563:Urodynamics; D055815:Young Adult
D003287:Contrast Media