Quantitative Assessment of Circumferential Enhancement along the Wall of Cerebral Aneurysms Using MR Imaging.

BACKGROUND AND PURPOSE: The incidence of wall enhancement of cerebral aneurysms on vessel wall MR imaging has been described as higher in ruptured intracranial aneurysms than in unruptured intracranial aneurysms, but the difference in the degree of enhancement between ruptured and unruptured aneurysms is unknown. We compared the degree of enhancement between ruptured and unruptured intracranial aneurysms by using quantitative MR imaging measures. MATERIALS AND METHODS: We performed quantitative analyses of circumferential enhancement along the wall of cerebral aneurysms in 28 ruptured and 76 unruptured consecutive cases by using vessel wall MR imaging. A 3D-T1-weighted fast spin-echo sequence was obtained before and after contrast media injection, and the wall enhancement index was calculated. We then compared characteristics between ruptured and unruptured aneurysms. RESULTS: The wall enhancement index was significantly higher in ruptured than in unruptured aneurysms (1.70 ± 1.06 versus 0.89 ± 0.88, respectively; P = .0001). The receiver operating characteristic curve analysis found that the most reliable cutoff value of the wall enhancement index to differentiate ruptured from unruptured aneurysms was 0.53 (sensitivity, 0.96; specificity, 0.47). The wall enhancement index remained significant in the multivariate logistic regression analysis (P < .0001). CONCLUSIONS: Greater circumferential enhancement along the wall of cerebral aneurysms correlates with the ruptured state. A quantitative evaluation of circumferential enhancement by using vessel wall MR imaging could be useful in differentiating ruptured from unruptured intracranial aneurysms.

[Experimental minute gastric cancer induced by N-ethyl-N'-nitro-N-nitrosoguanidine in dogs].

150 micrograms/day of N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) was administered to a total of 8 dogs, (4 mongrels at age of 4 months and 4 beagles at age of 6 months) over a period of 8 months by Kurihara 's method. As a result of the administration, we found development of minute cancer as follows: In 3 animals, male beagle killed at 575th day, male mongrel at 1, 105th days and male mongrel at 1, 245th days, a total of 20 neoplasms of the stomach was found (18 early cancers and 2 advanced cancers). 13 of which being the minute cancer measuring less than 0.5 cm. There were 11 mucosal cancers and 2 submucosal cancers. When classified by the macroscopic pathological type, none was classified as the elevated type (I, IIa types), 5 lesions as the flat type (IIb type), and 8 lesions as the depression type (IIc type). Two lesions of submucosal cancer belonged to IIc type. When classified by the histological type, 2 were classified as papillary adenocarcinoma, 2 as well differentiated tubular adenocarcinoma, 1 as moderately differentiated tubular adenocarcinoma, 5 as poorly differentiated adenocarcinoma and 3 as signet-ring cell carcinoma.