Bowel sonography in sepsis with pathological correlation: an experimental study.
BACKGROUND
Sepsis predisposes full-term infants to necrotizing enterocolitis (NEC). As such, experimental induction of NEC was applied to a sepsis model to evaluate the potential role of US in the early diagnosis of NEC in full-term infants.


OBJECTIVE
To evaluate the resistive index (RI) of the superior mesenteric artery (SMA) on Doppler sonography in experimentally induced sepsis and correlate it with the pathological findings.


METHODS
Fifteen 1-week-old New Zealand white rabbits (control group n = 3, sepsis group n = 12) were used in this study. We injected 1 mg/kg of E. coli O55-B5 lipopolysaccharide (LPS) into 12 rabbits to induce sepsis. Then we conducted grayscale evaluation of the caliber of the abdominal aorta as well as bowel wall thickness and echogenicity. In addition, we measured peak systolic and end-diastolic velocities and SMA RI on Doppler sonography. Pathological findings were analyzed and correlated with RI readings. Peak systolic and end-diastolic velocities and SMA RI values were analyzed statistically at each hour using the Wilcoxon rank sum test; the control and sepsis groups were compared using the Mann-Whitney test.


RESULTS
The bowel wall thickness in the sepsis group was significantly increased after LPS injection. The caliber of the abdominal aorta in the sepsis group was significantly decreased after LPS injection. There were echogenic foci (<10 in axial plane) in the bowel wall after LPS injection. Peak systolic velocity in the sepsis group was not significantly changed, but end-diastolic velocity was decreased. SMA RIs in the sepsis group were significantly increased post-LPS injection from baseline. In the control group there were no significant changes in bowel wall thickness, abdominal aorta caliber, bowel wall echogenicity or peak systolic and end-diastolic velocities and RIs. Pathologically, eight of the 12 rabbits in the sepsis group showed grade 1 intestinal injury, three showed grade 2 injury and one showed grade 3 injury. SMA RIs were higher in grades 2 and 3 than in grade 1 when measured at 2 h and 4 h.


CONCLUSIONS
Sepsis caused necrotic injury in the animal models, and these findings were accompanied by significant changes on Doppler US. These findings could facilitate early detection of intestinal injury in septic infants with NEC.
Kim
Hwa-Young
HY
Department of Radiology, Seoul National University College of Medicine and Institute of Radiation Medicine, 101 Daehangno, Jongno-Gu, Seoul, 110-744, South Korea.
Kim
In-One
IO
Kim
Woo Sun
WS
Kang
Gyeong Hoon
GH
D000818:Animals; D004195:Disease Models, Animal; D020345:Enterocolitis, Necrotizing / Q000150:complications* / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D011817:Rabbits; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018805:Sepsis / Q000150:complications* / Q000000981:diagnostic imaging* / Q000473:pathology; D013223:Statistics as Topic; D014463:Ultrasonography / Q000379:methods*