Evolution of two unusual radiological findings in a patient with mesenteric ischemia.

Portal pneumatosis has been considered an ominous sign associated with intestinal ischemia, with a mortality rate of up to 90% as long as it is associated with sepsis. However, the prognosis of mesenteric ischemia depends on the etiology rather than the presence of portal pneumatosis. We present a patient with portal pneumatosis that disappeared 24 hours after the first surgery, but irreversible ischemic lesions were established in the terminal ileum. It should be noted that the excretion of the intravenous contrast is mainly through the kidneys, and it can be eliminated through alternative routes such as the bile duct or the mucosa of the small intestine (vicariant excretion), especially in patients with renal pathology.

The value of metabolic imaging to predict tumour response after chemoradiation in locally advanced rectal cancer.

BACKGROUND: We aim to investigate the possibility of using 18F-positron emission tomography/computer tomography (PET-CT) to predict the histopathologic response in locally advanced rectal cancer (LARC) treated with preoperative chemoradiation (CRT). METHODS: The study included 50 patients with LARC treated with preoperative CRT. All patients were evaluated by PET-CT before and after CRT, and results were compared to histopathologic response quantified by tumour regression grade (patients with TRG 1-2 being defined as responders and patients with grade 3-5 as non-responders). Furthermore, the predictive value of metabolic imaging for pathologic complete response (ypCR) was investigated. RESULTS: Responders and non-responders showed statistically significant differences according to Mandard's criteria for maximum standardized uptake value (SUVmax) before and after CRT with a specificity of 76,6% and a positive predictive value of 66,7%. Furthermore, SUVmax values after CRT were able to differentiate patients with ypCR with a sensitivity of 63% and a specificity of 74,4% (positive predictive value 41,2% and negative predictive value 87,9%); This rather low sensitivity and specificity determined that PET-CT was only able to distinguish 7 cases of ypCR from a total of 11 patients. CONCLUSIONS: We conclude that 18-F PET-CT performed five to seven weeks after the end of CRT can visualise functional tumour response in LARC. In contrast, metabolic imaging with 18-F PET-CT is not able to predict patients with ypCR accurately.