Stercoral colitis: CT imaging findings and clinical risk factors.

PURPOSE: To describe and update stercoral colitis clinical risk factors, relative frequency, location, and CT imaging features correlated with surgical and pathological results. METHODS: CT reports over a 5-year period (05/2017-05/2022) at a single medical center were searched. Main inclusion criteria were luminal distention with formed stool, wall thickening, and surrounding inflammation. Positive cases were graded as mild (early or developing stercoral colitis) versus moderate-to-severe based on CT findings. Medical records were reviewed for risk factors and outcome data in moderate-to-severe cases. P-values were tabulated for comparison. RESULTS: 545 total cases (71 (60, 82) years, 278 males) were identified on CT, including 452 mild (82.9%) and 93 moderate-to-severe cases (17%, 67 (55, 79) years, 48 females). Twenty cases showed evidence of perforation (3.7% total cohort, 22% moderate-to-severe cohort). Diagnosis as an incidental finding was frequent (46.0% of mild cases). Most cases involved the rectum (97.6% of mild cohort and 69% of moderate-to-severe cohort). The sigmoid was involved in 31% of moderate-to-severe cases, but 95% of the perforated subcohort (19/20, 13/20 without rectal involvement). Among the moderate-to-severe cohort, perforation was associated with slightly increased wall thickness (6.4 vs. 5.7 mm, p = 0.03), opioid use (50 vs. 23%, p = 0.04), and disease-specific mortality (11 vs. 0%, p =0.04). Perforation was less associated with major neurocognitive disorders (20 vs. 60%, p = 0.003), institutionalized status (5 vs. 38%, p = 0.005), and a prescribed bowel regimen (30 vs. 63%, p = 0.01). CONCLUSION: Stercoral colitis may be under-reported. Perforation tends to favor sigmoid involvement and a less traditional patient cohort.

Small bowel neuroendocrine neoplasm: what surgeons want to know.

Neuroendocrine neoplasms of the small bowel are a diverse group of tumors with a broad spectrum of imaging findings and clinical implications. Most tumors originate in close proximity to the ileocecal valve and most commonly metastasize to the mesentery and liver. This review will highlight the imaging findings of primary and metastatic small bowel neuroendocrine neoplasm that are most relevant to the surgical team.

Hydride transfer reaction dynamics of OD+ +C3H6.

The hydride transfer reaction between OD+ and C3H6 has been studied experimentally and theoretically over the center of mass collision energy range from 0.21 to 0.92 eV using the crossed beam technique and density functional theory calculations. The center of mass flux distributions of the product ions at three different energies are highly asymmetric, with maxima close to the velocity and direction of the precursor propylene beam, characteristic of direct reactions. In the hydride transfer process, the entire reaction exothermicity is transformed into product internal excitation, consistent with mixed energy release in which the hydride ion is transferred with both the breaking and forming bonds extended. At higher collision energies, at least 85% of the incremental translational energy appears in product translation, providing a clear example of induced repulsive energy release. Compared to the related reaction of OD+ with C2H4, reaction along the pathway initiated by addition of OD+ to the C=C bond in propylene has a critical bottleneck caused by the torsional motion of the methyl substituent on the double bond. This bottleneck suppresses reaction through an intermediate complex in favor of direct hydride abstraction. Hydride abstraction appears to be a sequential process initiated by electron transfer in the triplet manifold, followed by rapid intersystem crossing and subsequent hydrogen atom transfer to form ground state allyl cation and HOD.