Quantitative assessment of pancreatic fat by using unenhanced CT: pathologic correlation and clinical implications.
OBJECTIVE
To assess the relationship between computed tomographic (CT) indexes and histologically measured pancreatic fat in surgical specimens and to evaluate patients with impaired glucose metabolism in a clinical setting.


METHODS
This retrospective study was institutional review board approved and informed consent was waived. The hospital database was searched for records from November 2008 to April 2009, and 62 patients (42 men and 20 women; mean age, 61.4 years; age range, 21-81 years) who underwent CT within 1 month before pancreatectomy were identified. The histologic pancreatic fat fraction (area ratio of fat to total tissue times 100%) was measured in nontumorous pancreatic tissue. Attenuation was measured in three regions of interest in the pancreas and the spleen on nonenhanced CT images. The difference between pancreatic and splenic attenuation and the pancreas-to-spleen attenuation ratio were calculated. Visceral fat area at the level of the umbilicus was measured on the CT images. Spearman correlation coefficients (ρ) were calculated to examine the correlation between the CT indexes or visceral fat area and the histologic pancreatic fat fraction. A multivariate logistic regression model was used to determine whether CT attenuation indexes and patient age, sex, and visceral fat correlated with impaired glucose metabolism (ie, impaired glucose tolerance, impaired fasting glucose, or presence of diabetes).


RESULTS
The histologic pancreatic fat fraction ranged from 0% to 65.3% and was significantly correlated with the difference between pancreatic and splenic attenuation (ρ = -0.622, P < .01) and the pancreas-to-spleen attenuation ratio (ρ = -0.616, P < .01). The visceral fat area was not correlated with the histologic pancreatic fat fraction (ρ = 0.09, P = .50). The CT attenuation indexes were significant and independent variables predictive of impaired glucose metabolism after adjusting for age, sex, and visceral fat.


CONCLUSIONS
Pancreatic fat can be quantified by using CT, and CT attenuation indexes that are applied to the quantification of pancreatic fat are significantly associated with clinical assessment of impaired glucose metabolism.
From the Departments of Radiology (S.Y.K., K.H.L., Y.H.K., H.S.K.), Pathology (H.K.), Surgery (J.Y.C., J.H.K., Y.S.Y., H.S.H.), and Internal Medicine (S.L.), Seoul National University College of Medicine, Seoul National University Bundang Hospital, 300 Gumi-dong, Bundang-gu, Seongnam-si, Gyeonggi-do 463-707, Korea; and Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pa (K.C.).
So Yeon
SY
Kim
Haeryoung
H
Kim
Jai Young
JY
Cho
Soo
S
Lim
Kyusun
K
Cha
Kyoung Ho
KH
Lee
Young Hoon
YH
Kim
Ji Hoon
JH
Kim
Yoo-Seok
YS
Yoon
Ho-Seong
HS
Han
Heung Sik
HS
Kang
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D005260:Female; D006801:Humans; D050152:Intra-Abdominal Fat / Q000000981:diagnostic imaging* / Q000473:pathology; D007472:Iohexol / Q000031:analogs & derivatives; D008297:Male; D008875:Middle Aged; D010180:Pancreatectomy; D010182:Pancreatic Diseases / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*
D003287:Contrast Media; D007472:Iohexol; C038192:iopromide