Keywords:
Gastrointestinal tract, MR, Experimental, Experimental investigations, Ischaemia / Infarction
Authors:
D. Berritto1, F. Iacobellis1, M. P. Belfiore1, M. A. Mazzei2, L. Saba3, R. Di Mizio4, S. Cappabianca1, A. Rotondo1, R. Grassi1; 1Naples/IT, 2Siena/IT, 3Cagliari/IT, 4Penne/IT
DOI:
10.1594/ecr2013/B-0057
Results
In the first hour it was not possible to detect MRI findings that helped in distinguishing these two conditions: in both groups hyper-intense signal in T2-W sequences in the intestinal wall was detected,
as well as the presence of free fluid. These findings are concordant with the pathological analysis that showed chromatic change (from pink to dark red) of the bowel (Fig.
1).
Histological analysis showed a patchy inflammatory pattern and vascular congestion with the development of supepithelial edema (Grunhagen’s space).
In the second hour,
the hypotonic reflex ileus (HRI) (average diameter of intestinal lumen of 4.2 mm) represented the first sign helping to identify the I\R and to distinguish it from the SMV occlusionin the Group II (I\R): in the 100% of the rats after I/R,
the HRI was found whereas this finding was not present after SMV occlusion.
In both cases there was the hyper-intense signal in T2-W sequences in the intestinal wall,
the free fluid and the bowel wall thickening (Fig.
2).
The pathological and histological analysis confirmed these MRI findings with the early loss of the normal shape of villi with the destruction of the free portion and spared glandular structures and dilated and congested vessels.
In the fourth hour the congested mesentery was detectable only in those rats with SMV occlusion while the paralytic ileus (PI) was visible in both groups from the sixth hour.
Only in 1 case of VMI was observed wall pneumatosis after eighth hours (Fig 3).
In the Group I,
at the fourth hour hemorrhage and congestion were evident at histological analysis both in the basal glandular area and in the mesentery.
In the sixth and eight hour histological findings were similar with an intense structural wrecking of the villi leaded to the replacement of the free portion of the villi with a large amount of inflammatory and necrotic material. In the tissue samples taken at the fourth,
sixth and eighth hours of the reperfusion the mucosa was characterized by development of subepithelial Gruenhagen’s space,
usually at the apex of the villus,
often with capillary congestion.