Segmentation of subtraction images for the measurement of lesion change in multiple sclerosis.

BACKGROUND AND PURPOSE: Lesion volume change (LVC) assessment is essential in monitoring MS progression. LVC is usually measured by independently segmenting serial MR imaging examinations. Subtraction imaging has been proposed for improved visualization and characterization of lesion change. We compare segmentation of subtraction images (SSEG) with serial single time-point conventional segmentation (CSEG) by assessing the LVC relationship to brain atrophy and disease duration, as well as scan-rescan reproducibility and annual rates of lesion accrual. MATERIALS AND METHODS: Pairs of scans were acquired 1.5 to 4.7 years apart in 21 patients with multiple sclerosis (MS). Scan-rescan MR images were acquired within 30 minutes in 10 patients with MS. LVC was measured with CSEG and SSEG after coregistration and normalization. Coefficient of variation (COV) and Bland-Altman analyses estimated method reproducibility. Spearman rank correlations probed associations between LVC and other measures. RESULTS: Atrophy rate and net LVC were associated for SSEG (R = -0.446; P < .05) but not when using CSEG (R = -0.180; P = .421). Disease duration did not show an association with net lesion volume change per year measured by CSEG (R = -0.360; P = .11) but showed an inverse correlation with SSEG-derived measurements (R = -0.508; P < .05). Scan-rescan COV was lower for SSEG (0.98% +/- 1.55%) than for CSEG (8.64% +/- 9.91%). CONCLUSION: SSEG unveiled a relationship between T2 LVC and concomitant brain atrophy and demonstrated significantly higher measurement reproducibility. SSEG, a promising tool providing detailed analysis of subtle alterations in lesion size and intensity, may provide critical outcome measures for clinical trials of novel treatments, and may provide further insight into progression patterns in MS.

["Open abdomen" in the treatment of necrosis in acute pancreatitis]. / Az akut pancreatitist kísérö necrosisok kezelése "nyitott has" módszerével.

Eleven cases of acute necrotic pancreatitis had been treated by "open abdomen" at the author's departments. Nine patients survived, but 2 patients had been lost in MOF. Indication, technics and complications are discussed. The author's opinion is, that--on the basis of a suitable indication--"open abdomen" is a good method in the treatment of the necrosis in acute pancreatitis.

Alteration in the reactivity of hamster cheek pouch arterioles to prostaglandin E2 and noradrenaline during pregnancy or sex steroid treatment.

Dioestrous and pregnant, or ovariectomized hamsters treated with sunflower oil, oestradiol or progesterone were anesthetized with pentobarbital and the arterioles of the cheek pouch membrane were prepared for microcirculatory study. Prostaglandin E2 (PGE2) or noradrenaline (NA) were topically applied and changes of the arteriolar diameter were measured on the screen of a closed-circuit television. PGE2 induced arteriolar dilatation in dioestrous or ovariectomized hamsters, but induced vasoconstriction in pregnant or in oestrogen-treated animals. Vasoconstriction induced by PGE2 in oestrogen-treated animals disappeared after administration of alpha-adrenergic blockers. In this situation, PGE2 induced vasodilatation once again. NA elicited arteriolar constriction in each experimental group. In ovariectomized hamsters treated with oestrogen the constriction was more pronounced than in progesterone treated animals. In pregnant animals it was significantly greater on day 14 than in dioestrous animals. Progesterone treatment blunted the vascular effect of both PGE2 and NA. It was concluded that the reverse effect of PGE2 and the increased sensitivity to NA induced by high oestradiol levels may have roles in the regulation of local blood flow during the ovarian cycle and pregnancy.